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Sample records for resulting radiation hotspots

  1. Accumulation of radium in ferruginous protein bodies formed in lung tissue: association of resulting radiation hotspots with malignant mesothelioma and other malignancies

    PubMed Central

    Nakamura, Eizo; Makishima, Akio; Hagino, Kyoko; Okabe, Kazunori

    2009-01-01

    While exposure to fibers and particles has been proposed to be associated with several different lung malignancies including mesothelioma, the mechanism for the carcinogenesis is not fully understood. Along with mineralogical observation, we have analyzed forty-four major and trace elements in extracted asbestos bodies (fibers and proteins attached to them) with coexisting fiber-free ferruginous protein bodies from extirpative lungs of individuals with malignant mesothelioma. These observations together with patients’ characteristics suggest that inhaled iron-rich asbestos fibers and dust particles, and excess iron deposited by continuous cigarette smoking would induce ferruginous protein body formation resulting in ferritin aggregates in lung tissue. Chemical analysis of ferruginous protein bodies extracted from lung tissues reveals anomalously high concentrations of radioactive radium, reaching millions of times higher concentration than that of seawater. Continuous and prolonged internal exposure to hotspot ionizing radiation from radium and its daughter nuclides could cause strong and frequent DNA damage in lung tissue, initiate different types of tumour cells, including malignant mesothelioma cells, and may cause cancers. PMID:19644223

  2. BENCHMARKING UPGRADED HOTSPOT DOSE CALCULATIONS AGAINST MACCS2 RESULTS

    SciTech Connect

    Brotherton, Kevin

    2009-04-30

    The radiological consequence of interest for a documented safety analysis (DSA) is the centerline Total Effective Dose Equivalent (TEDE) incurred by the Maximally Exposed Offsite Individual (MOI) evaluated at the 95th percentile consequence level. An upgraded version of HotSpot (Version 2.07) has been developed with the capabilities to read site meteorological data and perform the necessary statistical calculations to determine the 95th percentile consequence result. These capabilities should allow HotSpot to join MACCS2 (Version 1.13.1) and GENII (Version 1.485) as radiological consequence toolbox codes in the Department of Energy (DOE) Safety Software Central Registry. Using the same meteorological data file, scenarios involving a one curie release of {sup 239}Pu were modeled in both HotSpot and MACCS2. Several sets of release conditions were modeled, and the results compared. In each case, input parameter specifications for each code were chosen to match one another as much as the codes would allow. The results from the two codes are in excellent agreement. Slight differences observed in results are explained by algorithm differences.

  3. Drone Detects Hotspots of Radiation and CO2 Outgassing

    NASA Astrophysics Data System (ADS)

    Takac, M.; Kletetschka, G.

    2016-12-01

    Market availability of environmental sensors and drones allow drones to become part of the education activities promoting environmental science both in high schools and grade schools. Here we provide one mode of drone operation for potential use in educational framework.Drone can carry devices that are capable of measuring various parameters of the environment. Commercial radiation and gas (CO2) sensors can be attached to the commercial drone. Our specific drone acquired data set of CO2 measurements over the natural outgassing of CO2 and another set of measurements over old uranium mine. Measurements of CO2 gave a poor signal to noise ratio. Its sensitivity, however, was enough to detect an increase in CO2 in the closed room with humans present compared to the fresh air outside. We could measure an increase of CO2 when directly over the source of natural CO2 outburst. Our data showed that CO2 concentration quickly dilutes in air few meters from the source to concentrations that are within the noise limit. However, the radiation measurements provided a map that correlates well with radiation survey obtained by ground measurements with more sophisticated instrument. We used the most common conventional drone, which is on the market and highly effective personal dosimeter, which can also be used for fire and rescue for its durability. Experimental field measurements were done at Třebsko site, where a map of radioactivity using standard spot measurements was already done. A field experiment was done in winter months when demand for the drone was higher due to cold and wet weather. We tested profiles and height versus the intensity of the recorded signal measurements. We consulted our results and ability to measure radioactivity with the regional fire-fighting units headquarters and verify the applicability and use of this technology for their needs.

  4. Spatial Patterns in Discordant Diagnostic Test Results for Chagas Disease: Links to Transmission Hotspots

    PubMed Central

    Levy, Michael Z.; Bowman, Natalie M.; Kawai, Vivian; Plotkin, Joshua B.; Waller, Lance A.; Cabrera, Lilia; Steurer, Frank; Seitz, Amy E.; Pinedo-Cancino, Viviana V.; Carpio, Juan Geny Cornejo del; Benzaquen, Eleazar Cordova; McKenzie, F. Ellis; Maguire, James H.; Gilman, Robert H.; Bern, Caryn

    2009-01-01

    Diagnosis of Chagas disease is hindered by discordance between screening and confirmatory test results for Trypanosoma cruzi infection. In periurban Arequipa, Peru, spatial analysis revealed that individuals with discordant test results are spatially clustered in hotspots of T. cruzi transmission, suggesting that discordant results likely represent true infections in this setting. PMID:19278335

  5. Spatial patterns in discordant diagnostic test results for Chagas disease: links to transmission hotspots.

    PubMed

    Levy, Michael Z; Bowman, Natalie M; Kawai, Vivian; Plotkin, Joshua B; Waller, Lance A; Cabrera, Lilia; Steurer, Frank; Seitz, Amy E; Pinedo-Cancino, Viviana V; Cornejo del Carpio, Juan Geny; Cordova Benzaquen, Eleazar; McKenzie, F Ellis; Maguire, James H; Gilman, Robert H; Bern, Caryn

    2009-04-15

    Diagnosis of Chagas disease is hindered by discordance between screening and confirmatory test results for Trypanosoma cruzi infection. In periurban Arequipa, Peru, spatial analysis revealed that individuals with discordant test results are spatially clustered in hotspots of T. cruzi transmission, suggesting that discordant results likely represent true infections in this setting.

  6. Juno-JIRAM: Overview of Preliminary Results in the Study of Jupiter Hot-Spots

    NASA Astrophysics Data System (ADS)

    Adriani, A.; Grassi, D.; Sindoni, G.; Mura, A.; Noschese, R.; Cicchetti, A.; Altieri, F.; Dinelli, B. M.; Moriconi, M. L.; Fabiano, F.; Migliorini, A.; Filacchione, G.; Tosi, F.; Piccioni, G.; Turrini, D.; Bolton, S. J.; Levin, S.; Connerney, J. E. P.; Olivieri, A.

    2016-12-01

    The JIRAM instrument on board of the Juno spacecraft includes a spectrometer channel that operates in the range 2-5 μm with a spectral resolution of about 14 nm.Data from this channel are particularly valuable in the study of the hot-spots, regions of the Jupiter atmosphere where the upper cloud decks are relatively thin and the thermal radiation emitted at pressures down to 3-4 bars can be measured by infrared remote-sensing instruments. Previous studies on NIMS-Galileo [1] and VIMS-Cassini [2] data, as well as a specific assessment for the JIRAM instrument [3], have demonstrated the possibility to constraints the content of H2O, NH3 and PH3 from moderate-resolution spectra of hot spots covering the CH4 transparency window at 5 μm.This talk reviews the first results on the retrieval of these species from the JIRAM observations acquired around the first Juno pericenter after the orbit insertion. The specific characteristics of the orbit have made possible a fairly complete latitudinal and longitudinal coverage of the thermal emissions at low emission angles over large portions of the Jupiter disk. Maps of gas content are compared against the previous results derived from NIMS, VIMS and ISO spectra.[1] Irwin et al., 1998, doi:10.1029/98JE00948[2] Giles et al., 2015, doi:10.1016/j.icarus.2015.05.030[3] Grassi et al., 2010, doi:10.1016/j.pss.2010.05.003

  7. Motion of Hawaii and Louisville hotspots: Comparision of modeling results with new age and paleolatitude data

    NASA Astrophysics Data System (ADS)

    Steinberger, B. M.; O'Connor, J. M.; Koppers, A. A.

    2011-12-01

    The bend in the Hawaiian-Emperor Chain is often seen as a consequence of Pacific plate motion change. Alternatively, it may record a change in motion of the Hawaii hotspot, or a combination of both. In order to devise a common reference frame for plate motions and flow in the mantle, which is needed to understand plate-mantle interaction, it is important to resolve that issue. Here we contribute towards that goal by comparing predictions of a geodynamic model of hotspot motion with new age and paleolatitude data from the Hawaiian-Emperor and Louisville chains. These are the two most prominent hotspot tracks on the Pacific plate and hence most suitable to constrain its motion. Comparing the age progression along both tracks can tell about the relative motion or fixity of the two hotspots, whereas paleo-latitude data ideally can resolve hotspot motion relative to the pole. However, their interpretation also needs to consider the possibility of true polar wander -- re-orientation of the entire Earth including the mantle relative to the pole. To model hotspot motion, we first compute large-scale mantle flow. Mantle density anomalies are inferred from seismic tomography models, assuming both density and seismic velocity anomalies are due to temperature anomalies, except in parts of the uppermost mantle (tectosphere) and possibly parts of the lowermost mantle (Large Low Shear Velocity Provinces). Radial mantle viscosity structure is chosen such that it is consistent with mineral physics, and the "Haskell average" inferred from postglacial rebound observations, and the model prediction of the geoid and global heat flux agrees well with observations. Time dependence is achieved by considering changes in plate motions and geometry as mantle flow boundary conditions, and advecting density anomalies back with the flow. Secondly we compute the motion of plume conduits in large-scale flow, assuming conduits are vertical at an initial time, and subsequently move with the flow

  8. Secondary Hotspots in the South Pacific as a Result of Mantle Plumelets and Lithospheric Extension?

    NASA Astrophysics Data System (ADS)

    Koppers, A.; Staudigel, H.; Wijbrans, J.; Pringle, M.

    2003-12-01

    By far the largest number of secondary hotspots (cf. Courtillet et al., 2003) can be found in the "South Pacific Thermal and Isotopic Anomaly" (SOPITA) or "Superswell" region. Its Cretaceous counterpart is preserved in a large range of seamounts and guyots found in the "West Pacific Seamount Province" (WPSP). The seamounts in these regions display very distinct and long-lived isotopic signatures (Staudigel et al., 1991; Koppers et al., 2003) that can be used to combine source region chemistry and seamount geochronology to map out mantle melting anomalies over geological time. These mappings may resolve many important questions regarding the stationary character, continuity and longevity of the melting anomalies in the South Pacific mantle - and its secondary hotspots. Of all secondary hotspots that are currently active in the SOPITA we could identify only two hotspots that appear to be long-lived and that have Cretaceous counterparts in the WPSP. Plate reconstructions show that the "HIMU-type" Southern Wake seamounts may have originated from the Mangaia-Rurutu "hotline" in the Cook-Austral Islands, whereas the "EMI-type" Magellan seamounts may have originated from the Rarotonga hotspot. All other hotspots in the SOPITA and WPSP are short-lived (or intermittently active) as evidenced by the presence of numerous seamount trail "segments" representing no more than 10-40 Myr of volcanism. Our observations violate one or more assumptions of the classical Wilson-Morgan hotspot hypothesis: (1) none of the South Pacific hotspots are continuously active, (2) most are short-lived, (3) some show evidence of hotspot motion, and (4) most of them have poor linear age progressions, if any at all. On top of this we have evidence for volcanism along "hotlines" and the "superposition" of hotspots. The simple and elegant "hotspot" model, therefore, seems insufficient to explain the age distribution and source region characteristics of intra-plate volcanoes in the South Pacific. This

  9. Are there "local hotspots?" When concepts of cognitive psychology do not fit with physiological results.

    PubMed

    Gaucher, Quentin; Edeline, Jean-Marc

    2016-01-01

    Mather and colleagues' arguments require rethinking at the mechanistic level. The arguments on the physiological effects of norepinephrine at the cortical level are inconsistent with large parts of the literature. There is no evidence that norepinephrine induces local "hotspots": Norepinephrine mainly decreases evoked responses; facilitating effects are rare and not localized. More generally, the idea that perception benefits from "local hotspots" is hardly compatible with the fact that neural representations involve largely distributed activation of cortical and subcortical networks.

  10. Correlation Between Interphase Chromatin Structure and - and High-Let Radiation-Induced - and Intra-Chromosome Exchange Hotspots

    NASA Astrophysics Data System (ADS)

    Zhang, Ye; Wu, Honglu; Mangala, Lingegowda; Asaithamby, Aroumougame; Chen, David

    2012-07-01

    CORRELATION BETWEEN INTERPHASE CHROMATIN STRUCTURE AND LOW- AND HIGH-LET RADIATION-INDUCED INTER- AND INTRA-CHROMOSOME EXCHANGE HOTSPOTS Ye Zhang1,2, Lingegowda S. Mangala1,3, Aroumougame Asaithamby4, David J. Chen4, and Honglu Wu1 1 NASA Johnson Space Center, Houston, Texas, USA 2 Wyle Integrated Science and Engineering Group, Houston, Texas, USA 3 University of Houston Clear Lake, Houston, Texas, USA 4 University of Texas, Southwestern Medical Center, Dallas, Texas, USA To investigate the relationship between chromosome aberrations induced by low- and high-LET radiation and chromatin folding, we reconstructed the three dimensional structure of chromosome 3 and measured the physical distances between different regions of this chromosome. Previously, we investigated the location of breaks involved in inter- and intrachromosomal type exchange events in chromosome 3 of human epithelial cells, using the multicolor banding in situ hybridization (mBAND) technique. After exposure to both low- and high-LET radiations in vitro, intra-chromosome exchanges occurred preferentially between a break in the 3p21 and one in the 3q11 regions, and the breaks involved in inter-chromosome exchanges occurred in two regions near the telomeres of the chromosome. In this study, human epithelial cells were fixed in G1 phase and interphase chromosomes hybridized with an mBAND probe for chromosome 3 were captured with a laser scanning confocal microscope. The 3-dimensional structure of interphase chromosome 3 with different colored regions was reconstructed, and the distance between different regions was measured. We show that, in most of the G1 cells, the regions containing 3p21 and 3q11 are colocalized in the center of the chromosome domain, whereas, the regions towards the telomeres of the chromosome are located in the peripherals of the chromosome domain. Our results demonstrate that the distribution of breaks involved in radiation-induced inter and intra-chromosome aberrations depends

  11. APS undulator radiation: First results

    SciTech Connect

    Cai, Z.; Dejus, R.J.; Hartog, P.D.

    1995-12-31

    The first undulator radiation has been extracted from the Advanced Photon Source (APS). The results from the characterization of this radiation are very satisfactory. With the undulator set at a gap of 15.8 mm (K=1.61), harmonics as high as the 17th were observed using a crystal spectrometer. The angular distribution of the third-harmonic radiation was measured, and the source was imaged using a zone plate to determine the particle beam emittance. The horizontal beam emittance was found to be 6.9 {plus_minus} 1.0 nm-rad, and the vertical emittance coupling was found to be less than 3%. The absolute spectral flux was measured over a wide range of photon energies, and it agrees remarkably well with the theoretical calculations based on the measured undulator magnetic field profile and the measured beam emittance. These results indicate that both the emittance of the electron beam and the undulator magnetic field quality exceed the original specifications.

  12. Toad radiation reveals into-India dispersal as a source of endemism in the Western Ghats-Sri Lanka biodiversity hotspot

    PubMed Central

    Van Bocxlaer, Ines; Biju, SD; Loader, Simon P; Bossuyt, Franky

    2009-01-01

    Background High taxonomic level endemism in the Western Ghats-Sri Lanka biodiversity hotspot has been typically attributed to the subcontinent's geological history of long-term isolation. Subsequent out of – and into India dispersal of species after accretion to the Eurasian mainland is therefore often seen as a biogeographic factor that 'diluted' the composition of previously isolated Indian biota. However, few molecular studies have focussed on into-India dispersal as a possible source of endemism on the subcontinent. Using c. 6000 base pairs of mitochondrial and nuclear DNA, we investigated the evolutionary history and biogeography of true toads (Bufonidae), a group that colonized the Indian Subcontinent after the Indo-Asia collision. Results Contrary to previous studies, Old World toads were recovered as a nested clade within New World Bufonidae, indicating a single colonization event. Species currently classified as Ansonia and Pedostibes were both recovered as being non-monophyletic, providing evidence for the independent origin of torrential and arboreal ecomorphs on the Indian subcontinent and in South-East Asia. Our analyses also revealed a previously unrecognized adaptive radiation of toads containing a variety of larval and adult ecomorphs. Molecular dating estimates and biogeographic analyses indicate that the early diversification of this clade happened in the Western Ghats and Sri Lanka during the Late Oligocene to Early Miocene. Conclusion Paleoclimate reconstructions have shown that the Early Neogene of India was marked by major environmental changes, with the transition from a zonal- to the current monsoon-dominated climate. After arrival in the Western Ghats-Sri Lanka hotspot, toads diversified in situ, with only one lineage able to successfully disperse out of these mountains. Consequently, higher taxonomic level endemism on the Indian Subcontinent is not only the result of Cretaceous isolation, but also of invasion, isolation and radiation of

  13. Toad radiation reveals into-India dispersal as a source of endemism in the Western Ghats-Sri Lanka biodiversity hotspot.

    PubMed

    Van Bocxlaer, Ines; Biju, S D; Loader, Simon P; Bossuyt, Franky

    2009-06-11

    High taxonomic level endemism in the Western Ghats-Sri Lanka biodiversity hotspot has been typically attributed to the subcontinent's geological history of long-term isolation. Subsequent out of -- and into India dispersal of species after accretion to the Eurasian mainland is therefore often seen as a biogeographic factor that 'diluted' the composition of previously isolated Indian biota. However, few molecular studies have focussed on into-India dispersal as a possible source of endemism on the subcontinent. Using c. 6000 base pairs of mitochondrial and nuclear DNA, we investigated the evolutionary history and biogeography of true toads (Bufonidae), a group that colonized the Indian Subcontinent after the Indo-Asia collision. Contrary to previous studies, Old World toads were recovered as a nested clade within New World Bufonidae, indicating a single colonization event. Species currently classified as Ansonia and Pedostibes were both recovered as being non-monophyletic, providing evidence for the independent origin of torrential and arboreal ecomorphs on the Indian subcontinent and in South-East Asia. Our analyses also revealed a previously unrecognized adaptive radiation of toads containing a variety of larval and adult ecomorphs. Molecular dating estimates and biogeographic analyses indicate that the early diversification of this clade happened in the Western Ghats and Sri Lanka during the Late Oligocene to Early Miocene. Paleoclimate reconstructions have shown that the Early Neogene of India was marked by major environmental changes, with the transition from a zonal- to the current monsoon-dominated climate. After arrival in the Western Ghats-Sri Lanka hotspot, toads diversified in situ, with only one lineage able to successfully disperse out of these mountains. Consequently, higher taxonomic level endemism on the Indian Subcontinent is not only the result of Cretaceous isolation, but also of invasion, isolation and radiation of new elements after accretion to

  14. The Correlation of Interphase Chromatin Structure with the Radiation-Induced Inter- and Intrachromosome Exchange Hotspots

    NASA Technical Reports Server (NTRS)

    Zhang, Ye; Mangala, Lingegowda S.; Purgason, Ashley M.; Hada, Megumi; Cucinotta, Francis A.; Wu, Honglu

    2011-01-01

    To investigate the relationship between chromosome aberrations induced by radiation and chromatin folding, we reconstructed three dimensional structure of chromosome 3 and measured the physical distances between different regions of the chromosome. Previously, we have investigated the location of breaks involved in inter- and intrachromosomal type exchange events in human chromosome 3, using the multicolor banding in situ hybridization (mBAND) technique. In human epithelial cells exposed to both low- and high-LET radiations in vitro, we reported that intra-chromosome exchanges occurred preferentially between a break in the 3p21 and one in the 3q11 regions, and the breaks involving in inter-chromosome exchanges occurred in two regions towards the telomeres of the chromosome. Exchanges were also observed between a break in 3p21 and one in 3q26, but few exchanges were observed between breaks in 3q11 and 3q26, even though the two regions are located on the same arm of the chromosome. In this study, human epithelial cells were fixed at G1 phase and the interphase cells were hybridized using the XCyte3 mBAND kit from MetaSystems. The z-section images of chromosome 3 were captured with a Leica and an LSM 510 Meta laser scanning confocal microscopes. A total of 100 chromosomes were analyzed. The reconstruction of three dimensional structure of interphase chromosome 3 with six different colored regions was achieved using the Imaris software. The relative distance between different regions was measured as well. We further analyzed fragile sites on the chromosome that have been identified in various types of cancers. The data showed that, in majority of the cells, the regions containing 3p21 and 3q11 are colocalized in the center of the chromosome, whereas, the regions towards the telomeres of the chromosome are either physically wrapping outside the chromosome center or with arms sticking out. Our results demonstrated that the distribution of breaks involved in radiation

  15. Results and analysis of the hot-spot temperature experiment for a cable-in-conduit conductor with thick conduit

    NASA Astrophysics Data System (ADS)

    Sedlak, Kamil; Bruzzone, Pierluigi

    2015-12-01

    In the design of future DEMO fusion reactor a long time constant (∼23 s) is required for an emergency current dump in the toroidal field (TF) coils, e.g. in case of a quench detection. This requirement is driven mainly by imposing a limit on forces on mechanical structures, namely on the vacuum vessel. As a consequence, the superconducting cable-in-conduit conductors (CICC) of the TF coil have to withstand heat dissipation lasting tens of seconds at the section where the quench started. During that time, the heat will be partially absorbed by the (massive) steel conduit and electrical insulation, thus reducing the hot-spot temperature estimated strictly from the enthalpy of the strand bundle. A dedicated experiment has been set up at CRPP to investigate the radial heat propagation and the hot-spot temperature in a CICC with a 10 mm thick steel conduit and a 2 mm thick glass epoxy outer electrical insulation. The medium size, ∅ = 18 mm, NbTi CICC was powered by the operating current of up to 10 kA. The temperature profile was monitored by 10 temperature sensors. The current dump conditions, namely the decay time constant and the quench detection delay, were varied. The experimental results show that the thick conduit significantly contributes to the overall enthalpy balance, and consequently reduces the amount of copper required for the quench protection in superconducting cables for fusion reactors.

  16. Ependymomas: results of radiation treatment

    SciTech Connect

    Garrett, P.G.; Simpson, W.J.K.

    1983-08-01

    Between 1958 and 1980, 102 patients with the diagnosis of ependymoma were seen at the Princess Margaret Hospital. Eleven patients had recurrent disease or were treated elsewhere and 91 patients received radiation therapy following their primary surgical procedure. Fifty patients had cranial tumors and 41 had spinal tumors. The overall survival at five years was 60% and at 10 years was 54%. Those patients with spinal tumors did significantly better with a five year survival of 83% versus 43% for the group with cranial tumors. The other prognostic factors included tumor grade, functional status, age of the patient and interval from surgery to radiation. The most common site of relapse was at the original tumor location, but five patients did show spread through the craniospinal axis. An analysis of dose and the volume treated are made and recommendations for therapy given.

  17. Earth Radiation Budget Experiment - Preliminary seasonal results

    NASA Technical Reports Server (NTRS)

    Barkstrom, Bruce R.; Harrison, Edwin F.; Lee, Robert B., III

    1990-01-01

    Data from the Earth Radiation Budget Satellite (ERBS) and from the operational NOAA-9 satellite being placed in the archive of the earth Radiation Budget Experiment (ERBE) are discussed. The results of the ERBE data validation effort are reviewed along with ERBE solar constant observations and earth-viewing results. The latter include monthly average results for July 1985, annual average clear-sky fluxes, and annual average, zonal, and global results.

  18. Reunion hotspot magma chemistry over the past 65 m. y. : Results from Leg 115 of the Ocean Drilling Program

    SciTech Connect

    Fisk, M.R.; Duncan, R.A. ); Baxter, A.N. ); Greenough, J.D. ); Hargraves, R.B. ); Tatsumi, Yoshiyuki )

    1989-10-01

    Leg 115 of the Ocean Drilling Program recovered basalts from four locations along the hotspot track that leads from the Deccan flood basalts in India to Reunion Island in the western Indian Ocean (Sites 706, 707, 713, and 715). The drilled basalts range in age from 35 Ma (Site 706) to 64 Ma (Site 707), and including the Deccan basalts (66 to 68 Ma), Mauritius Island (0.2 to 8 Ma), and Reunion Island (0 to 2 Ma), seven sites are provided for sampling the volcanic record of the 5,000-km-long hotspot track. Chemical and age comparisons indicate that Site 707 lavas correlate with basalt units near the top of the Deccan flood basalt sequence. The lavas of Site 715 (55 to 60 Ma) are most similar to the islands of Mauritius and Reunion. Site 713 basalts (48 Ma) are similar to the earliest lavas of the Deccan province, and Site 706 basalts are intermediate in chemistry between those of central Indian spreading-ridge basalts and Reunion. Differences in lava compositions along the hotspot track can be related to variable mixing of plume and asthenospheric mantle, depending on the changing position of spreading-ridge segments and the hotspot during the opening of the Indian Ocean. Alternatively, time-dependent changes in the composition of hotspot melts may be due to a decrease in partial melting of a heterogeneous plume or to intrinsic changes in the composition of material supplied by the plume.

  19. Observed climate change hotspots

    NASA Astrophysics Data System (ADS)

    Turco, M.; Palazzi, E.; Hardenberg, J.; Provenzale, A.

    2015-05-01

    We quantify climate change hotspots from observations, taking into account the differences in precipitation and temperature statistics (mean, variability, and extremes) between 1981-2010 and 1951-1980. Areas in the Amazon, the Sahel, tropical West Africa, Indonesia, and central eastern Asia emerge as primary observed hotspots. The main contributing factors are the global increase in mean temperatures, the intensification of extreme hot-season occurrence in low-latitude regions and the decrease of precipitation over central Africa. Temperature and precipitation variability have been substantially stable over the past decades, with only a few areas showing significant changes against the background climate variability. The regions identified from the observations are remarkably similar to those defined from projections of global climate models under a "business-as-usual" scenario, indicating that climate change hotspots are robust and persistent over time. These results provide a useful background to develop global policy decisions on adaptation and mitigation priorities over near-time horizons.

  20. The mQTL hotspot on linkage group 16 for phenolic compounds in apple fruits is probably the result of a leucoanthocyanidin reductase gene at that locus

    PubMed Central

    2012-01-01

    Background Our previous study on ripe apples from a progeny of a cross between the apple cultivars ‘Prima’ and ‘Fiesta’ showed a hotspot of mQTLs for phenolic compounds at the top of LG16, both in peel and in flesh tissues. In order to find the underlying gene(s) of this mQTL hotspot, we investigated the expression profiles of structural and putative transcription factor genes of the phenylpropanoid and flavonoid pathways during different stages of fruit development in progeny genotypes. Results Only the structural gene leucoanthocyanidin reductase (MdLAR1) showed a significant correlation between transcript abundance and content of metabolites that mapped on the mQTL hotspot. This gene is located on LG16 in the mQTL hotspot. Progeny that had inherited one or two copies of the dominant MdLAR1 alleles (Mm, MM) showed a 4.4- and 11.8-fold higher expression level of MdLAR1 respectively, compared to the progeny that had inherited the recessive alleles (mm). This higher expression was associated with a four-fold increase of procyanidin dimer II as one representative metabolite that mapped in the mQTL hotspot. Although expression level of several structural genes were correlated with expression of other structural genes and with some MYB and bHLH transcription factor genes, only expression of MdLAR1 was correlated with metabolites that mapped at the mQTL hotspot. MdLAR1 is the only candidate gene that can explain the mQTL for procyanidins and flavan-3-ols. However, mQTLs for other phenylpropanoids such as phenolic esters, dihydrochalcones and flavonols, that appear to map at the same locus, have so far not been considered to be dependent on LAR, as their biosynthesis does not involve LAR activity. An explanation for this phenomenon is discussed. Conclusions Transcript abundances and genomic positions indicate that the mQTL hotspot for phenolic compounds at the top of LG16 is controlled by the MdLAR1 gene. The dominant allele of the MdLAR1 gene, causing increased

  1. HOTSPOT Health Physics codes for the PC

    SciTech Connect

    Homann, S.G.

    1994-03-01

    The HOTSPOT Health Physics codes were created to provide Health Physics personnel with a fast, field-portable calculation tool for evaluating accidents involving radioactive materials. HOTSPOT codes are a first-order approximation of the radiation effects associated with the atmospheric release of radioactive materials. HOTSPOT programs are reasonably accurate for a timely initial assessment. More importantly, HOTSPOT codes produce a consistent output for the same input assumptions and minimize the probability of errors associated with reading a graph incorrectly or scaling a universal nomogram during an emergency. The HOTSPOT codes are designed for short-term (less than 24 hours) release durations. Users requiring radiological release consequences for release scenarios over a longer time period, e.g., annual windrose data, are directed to such long-term models as CAPP88-PC (Parks, 1992). Users requiring more sophisticated modeling capabilities, e.g., complex terrain; multi-location real-time wind field data; etc., are directed to such capabilities as the Department of Energy`s ARAC computer codes (Sullivan, 1993). Four general programs -- Plume, Explosion, Fire, and Resuspension -- calculate a downwind assessment following the release of radioactive material resulting from a continuous or puff release, explosive release, fuel fire, or an area contamination event. Other programs deal with the release of plutonium, uranium, and tritium to expedite an initial assessment of accidents involving nuclear weapons. Additional programs estimate the dose commitment from the inhalation of any one of the radionuclides listed in the database of radionuclides; calibrate a radiation survey instrument for ground-survey measurements; and screen plutonium uptake in the lung (see FIDLER Calibration and LUNG Screening sections).

  2. Processes Driving the Adaptive Radiation of a Tropical Tree (Diospyros, Ebenaceae) in New Caledonia, a Biodiversity Hotspot

    PubMed Central

    Paun, Ovidiu; Turner, Barbara; Trucchi, Emiliano; Munzinger, Jérôme; Chase, Mark W.; Samuel, Rosabelle

    2016-01-01

    Due to its special geological history, the New Caledonian Archipelago is a mosaic of soil types, and in combination with climatic conditions this results in a heterogeneous environment across relatively small distances. A group of over 20 endemic species of Diospyros (Ebenaceae) has rapidly and recently radiated on the archipelago after a single long-distance dispersal event. Most of the Diospyros species in the radiating group are morphologically and ecologically well differentiated, but they exhibit low levels of DNA variability. To investigate the processes that shaped the diversification of this group we employed restriction site associated DNA sequencing (RADseq). Over 8400 filtered SNPs generally confirm species delimitations and produce a well-supported phylogenetic tree. Our analyses document local introgression, but only a limited potential for gene flow over longer distances. The phylogenetic relationships point to an early regional clustering among populations and species, indicating that allopatric speciation with respect to macrohabitat (i.e., climatic conditions) may have had a role in the initial differentiation within the group. A later, more rapid radiation involved divergence with respect to microhabitat (i.e., soil preference). Several sister species in the group show a parallel divergence in edaphic preference. Searches for genomic regions that are systematically differentiated in this replicated phenotypic divergence pointed to loci potentially involved in ion binding and cellular transport. These loci appear meaningful in the context of adaptations to soil types that differ in heavy-metal and mineral content. Identical nucleotide changes affected only two of these loci, indicating that introgression may have played a limited role in their evolution. Our results suggest that both allopatric diversification and (parapatric) ecological divergence shaped successive rounds of speciation in the Diospyros radiation on New Caledonia. PMID:26430059

  3. Processes Driving the Adaptive Radiation of a Tropical Tree (Diospyros, Ebenaceae) in New Caledonia, a Biodiversity Hotspot.

    PubMed

    Paun, Ovidiu; Turner, Barbara; Trucchi, Emiliano; Munzinger, Jérôme; Chase, Mark W; Samuel, Rosabelle

    2016-03-01

    Due to its special geological history, the New Caledonian Archipelago is a mosaic of soil types, and in combination with climatic conditions this results in a heterogeneous environment across relatively small distances. A group of over 20 endemic species of Diospyros (Ebenaceae) has rapidly and recently radiated on the archipelago after a single long-distance dispersal event. Most of the Diospyros species in the radiating group are morphologically and ecologically well differentiated, but they exhibit low levels of DNA variability. To investigate the processes that shaped the diversification of this group we employed restriction site associated DNA sequencing (RADseq). Over 8400 filtered SNPs generally confirm species delimitations and produce a well-supported phylogenetic tree. Our analyses document local introgression, but only a limited potential for gene flow over longer distances. The phylogenetic relationships point to an early regional clustering among populations and species, indicating that allopatric speciation with respect to macrohabitat (i.e., climatic conditions) may have had a role in the initial differentiation within the group. A later, more rapid radiation involved divergence with respect to microhabitat (i.e., soil preference). Several sister species in the group show a parallel divergence in edaphic preference. Searches for genomic regions that are systematically differentiated in this replicated phenotypic divergence pointed to loci potentially involved in ion binding and cellular transport. These loci appear meaningful in the context of adaptations to soil types that differ in heavy-metal and mineral content. Identical nucleotide changes affected only two of these loci, indicating that introgression may have played a limited role in their evolution. Our results suggest that both allopatric diversification and (parapatric) ecological divergence shaped successive rounds of speciation in the Diospyros radiation on New Caledonia. © The Author

  4. Results of radiation treatment of cerebellar medulloblastoma

    SciTech Connect

    Chin, H.W.; Maruyama, Y.

    1981-06-01

    A review of 20 patients with medulloblastoma who were treated with radiation treatment at the University of Kentucky Medical Center is presented. The age range was 1.5 to 31 years; only five patients were older than 16 years of age. A relationship between radiation dose and survival was obtained. A 5-year disease-free survival of 80% was obtained with a radiation dose of 5000 rad and more whereas only 15% of patients survived five years with a radiation dose of less than 5000. Treatment failures were mainly a result of local recurrence. This occurred in 78% of patients who were treated with radiation dosage of less than 5000 rad. The development of hydrocephalus appeared to be because of advanced disease and no 5-year survivors were noted in five patients who underwent systemic shunting procedure. A review of published data also supports a dose-dependent 5-year survival. Effective radiation treatment methods, along with doses to 5000 to 5500 rad, appear to lead to long term survival, frequent tumor cure and high performance outcome.

  5. A Western Pacific Hotspot?

    NASA Astrophysics Data System (ADS)

    MacPherson, C. G.; Hall, R.

    2003-04-01

    The petrology of volcanic rocks from the St. Andrew Strait and helium isotope ratios of backarc lavas from the Manus Basin have been used to propose the existence of an active hotspot beneath the eastern Bismarck Sea (Johnson et al., 1978; Macpherson et al., 1998). The past influence of this hotspot can be assessed by mapping its present location onto a plate tectonic reconstruction of the western Pacific (Macpherson and Hall, 2001). During the Middle Eocene the nascent Izu-Bonin-Mariana (IBM) arc lay above the hotspot. The volume of magma emplaced at the IBM arc at that time substantially exceeds the average magma production rate for mature island arcs. Furthermore, the ultramafic (boninitic) character of much of this magmatism requires elevated temperatures. The geochemistry of contemporaneous magmatism in the backarc resembles ocean island basalts and much of the backarc region experienced significant uplift at that time. All of these features can be explained by the influx of hot, buoyant, chemically distinct mantle beneath the IBM and its hinterland. The lithosphere lying above the hotspot during the later Eocene was subsequently subducted. During the Oligo-Miocene the hotspot was traversed by parts of the Caroline Plate where the Euripik Rise is found. This is an aseismic rise that possesses the geophysical characteristics of thickened oceanic crust formed by excess, basaltic magmatism and is the type of structure that would result from the passage of relatively young oceanic lithosphere over a mantle hotspot. Plate reconstruction for the western Pacific predicts a hotspot trail that is consistent with the Middle Eocene and Oligo-Miocene geology of the IBM and Caroline Plates, respectively (Macpherson and Hall, 2001). Parts of the trail have been disrupted by subsequent sea-floor spreading or lost through subduction but the remaining vestiges are consistent with the action of a thermal anomaly throughout much of the Cenozoic. More speculatively, buoyancy

  6. Hotspots in Hindsight

    NASA Astrophysics Data System (ADS)

    Julian, B. R.; Foulger, G. R.; Hatfield, O.; Jackson, S.; Simpson, E.; Einbeck, J.; Moore, A.

    2014-12-01

    Torsvik et al. [2006] suggest that the original locations of large igneous provinces ("LIPs") and kimberlites, and current locations of melting anomalies (hot-spots) lie preferentially above the margins of two Large Lower-Mantle Shear Velocity Provinces" (LLSVPs), at the base of the mantle, and that the correlation has a high significance level (> 99.9999%). They conclude the LLSVP margins are Plume-Generation Zones, and deep-mantle plumes cause hotspots and LIPs. This conclusion raises questions about what physical processes could be responsible, because, for example the LLSVPs are likely dense and not abnormally hot [Trampert et al., 2004]. The supposed LIP-hotspot-LLSVP correlations probably are examples of the "Hindsight Heresy" [Acton, 1959], of basing a statistical test upon the same data sample that led to the initial formulation of a hypothesis. In doing this, many competing hypotheses will have been considered and rejected, but this fact will not be taken into account in statistical assessments. Furthermore, probabilities will be computed for many subsets and combinations of the data, and the best-correlated cases will be cited, but this fact will not be taken into account either. Tests using independent hot-spot catalogs and mantle models suggest that the actual significance levels of the correlations are two or three orders of magnitude smaller than claimed. These tests also show that hot spots correlate well with presumably shallowly rooted features such as spreading plate boundaries. Consideration of the kimberlite dataset in the context of geological setting suggests that their apparent association with the LLSVP margins results from the fact that the Kaapvaal craton, the site of most of the kimberlites considered, lies in Southern Africa. These observations raise questions about the distinction between correlation and causation and underline the necessity to take geological factors into account. Fig: Left: Cumulative distributions of distances from

  7. Scaling results for the liquid sheet radiator

    NASA Technical Reports Server (NTRS)

    Chubb, Donald L.; Calfo, Frederick D.

    1989-01-01

    Surface tension forces at the edges of a thin liquid (approx 100 micrometers) sheet flow result in a triangularly shaped sheet. Such a geometry is ideal for an external flow radiator. The experimental investigation of such sheet flows was extended to large sheets (width = 23.5 cm, length = 3.5 m). Experimental L/W results are greater than the calculated results. However, more experimental results are necessary for a complete comparison. The calculated emissivity of a sheet of Dow-Corning 705 silicone oil, which is low temperature (300-400 K) candidate for a liquid sheet radiator (LSR), is greater than 0.8 for sheet thicknesses greater than 100 micrometers.

  8. Scaling results for the liquid sheet radiator

    NASA Astrophysics Data System (ADS)

    Chubb, Donald L.; Calfo, Frederick D.

    Surface tension forces at the edges of a thin liquid (approx 100 micrometers) sheet flow result in a triangularly shaped sheet. Such a geometry is ideal for an external flow radiator. The experimental investigation of such sheet flows was extended to large sheets (width = 23.5 cm, length = 3.5 m). Experimental L/W results are greater than the calculated results. However, more experimental results are necessary for a complete comparison. The calculated emissivity of a sheet of Dow-Corning 705 silicone oil, which is low temperature (300-400 K) candidate for a liquid sheet radiator (LSR), is greater than 0.8 for sheet thicknesses greater than 100 micrometers.

  9. RHUM-RUM, a Large-Scale Effort to Seismologically Image a Mantle Plume Under the Reunion Hotspot: Experiment Presentation and Initial Results

    NASA Astrophysics Data System (ADS)

    Sigloch, K.; Barruol, G.

    2014-12-01

    RHUM-RUM is a German-French geophysical experiment based on the seafloor and on islands surrounding the hotspot of La Réunion, western Indian Ocean. Its primary objective is to clarify the presence or absence of a mantle plume beneath the Reunion hotspot, which is thought to have first pierced the surface 65 million years ago with the eruption of the Deccan Traps on India. RHUM-RUM's central component is a one-year deployment (Oct 2012 - Nov 2013) of 57 broadband ocean-bottom seismometers (OBS) and hydrophones on an area of 2000x2000 km2 surrounding the hotspot. All OBS have been successfully recovered. We also have been operating 37 land seismometers on the islands of La Réunion, Mauritius, Rodrigues, southern Seychelles, îles Eparses, and on Madagascar between 2011 and 2014. As the data collection stage is drawing to a close, we discuss data yield and quality with respect to RHUM-RUM's primary purpose (passive seismological imaging through all depth levels of the mantle) and secondary applications ("environmental seismology" in a sparsely instrumented area, e.g., tracking of tropical cyclones). We give an overview of the research questions investigated by the RHUM-RUM group, and present preliminary results.

  10. Oceanic Hotspots

    NASA Astrophysics Data System (ADS)

    Batiza, Rodey

    2004-10-01

    The Wilson-Morgan hypothesis that fixed mantle plumes rising from deep in Earth's mantle give rise to linear island and seamount chains like Hawaii has been a leading idea in planetary geodynamics for many decades. However, the notion that these ascending columns of buoyant mantle material are fixed relative to each other or to a fixed reference frame has been questioned because the mean regional flow of the mantle (the so-called mantle wind) would be expected to entrain them and waft them about. Lately, even more fundamental questions have been raised regarding the existence of deep mantle conduits. In fact, the subject of plumes has become quite controversial, with important implications for ideas of mantle convection, Earth's differentiation, and planetary magma budgets and cooling. The appearance of Oceanic Hotspots: Intraplate Submarine Magmatism and Tectonics is thus timely. The 14 chapters contained in this nicely produced volume reflect in part the successful Franco-German collaboration spanning more than 17 years (1986 to present) and 15 expeditions to largely uncharted and unexplored regions of the South Pacific Ocean. The editors intended to produce a comprehensive multidisciplinary overview of oceanic plumes in this region, and in this they have succeeded, with both review and research chapters. Most papers document new discoveries and contain new data and/or new and original thinking, whereas others provide a broad overview and synthesis of existing data.

  11. On the Possible Relation of the Louisville Hotspot and Ontong Java Plateau from Integrated Ocean Drilling Program Expedition 330 Results

    NASA Astrophysics Data System (ADS)

    Koppers, A. A.; Yamazaki, T.; Geldmacher, J.; Scientific Party, E. 3; IODP Expedition 330 Scientific Party

    2011-12-01

    It has been hypothesized that the Ontong Java Plateau formed from the plume head of the Louisville mantle plume around 120 Ma. Integrated Ocean Drilling Program (IODP) Expedition 330 drilled five different guyots in the Louisville Seamount Trail ranging in age between 80 and 50 Ma. Paleolatitude estimates, 40Ar/39Ar radiometric ages and geochemical data collected during Expedition 330 will provide the ultimate test of whether the oldest Louisville seamounts were formed close to the 18-28°S (with an average of 24±2°) paleolatitude determined from basalt drilled on the Ontong Java Plateau during ODP Leg 192 and whether this Large Igneous Province (LIP) was genetically linked to the Louisville hotspot. If so, this would allow for the possibility that indeed the preceding plume head of the Louisville mantle upwelling caused the massive LIP volcanism forming the Ontong Java Plateau around 120 Ma. The outcome of such a test is of fundamental importance in our understanding of LIP and hotspot formation and lies at the heart of the mantle plume debate.

  12. SPITZER OBSERVATIONS OF HOTSPOTS IN RADIO LOBES

    SciTech Connect

    Werner, Michael W.; Murphy, David W.; Livingston, John H.; Gorjian, Varoujan; Jones, Dayton L.; Meier, David L.; Lawrence, Charles R.

    2012-11-10

    We have carried out a systematic search with Spitzer Warm Mission and archival data for infrared emission from the hotspots in radio lobes that have been described by Hardcastle et al. These hotspots have been detected with both radio and X-ray observations, but an observation at an intermediate frequency in the infrared can be critical to distinguish between competing models for particle acceleration and radiation processes in these objects. Between the archival and warm mission data, we report detections of 18 hotspots; the archival data generally include detections at all four IRAC bands, the Warm Mission data only at 3.6 {mu}m. Using a theoretical formalism adopted from Godfrey et al., we fit both archival and warm mission spectral energy distributions (SEDs)-including radio, X-ray, and optical data from Hardcastle as well as the Spitzer data-with a synchrotron self-Compton (SSC) model, in which the X-rays are produced by Compton scattering of the radio frequency photons by the energetic electrons which radiate them. With one exception, an SSC model requires that the magnetic field be less or much less than the equipartition value which minimizes total energy and has comparable amounts of energy in the magnetic field and in the energetic particles. This conclusion agrees with those of comparable recent studies of hotspots, and with the analysis presented by Hardcastle et al. We also show that the infrared data rule out the simplest synchrotron-only models for the SEDs. We briefly discuss the implications of these results and of alternate interpretations of the data.

  13. Preliminary results of radiation measurements on EURECA

    SciTech Connect

    Benton, E.V.; Frank, A.L.

    1995-03-01

    The eleven-month duration of the EURECA mission allows long-term radiation effects to be studied similarly to those of the Long Duration Exposure Facility (LDEF). Basic data can be generated for projections to crew doses and electronic and computer reliability on spacecraft missions. A radiation experiment has been designed for EURECA which uses passive integrating detectors to measure average radiation levels. The components include a Trackoscope, which employs fourteen plastic nuclear track detector (PNTD) stacks to measure the angular dependence of high LET (greater than or equal to 6 keV/micro m) radiation. Also included are TLD`s for total absorbed doses, thermal/resonance neutron detectors (TRND`s) for low energy neutron fluences and a thick PNTD stack for depth dependence measurements. LET spectra are derived from the PNTD measurements. Preliminary TLD results from seven levels within the detector array show that integrated dose inside the flight canister varied from 18.8 +/- 0.6 cGy to 38.9 +/- 1.2 cGy. The TLD`s oriented toward the least shielded direction averaged 53% higher in dose than those oriented away from the least shielded direction (minimum shielding toward the least shielded direction varied from 1.13 to 7.9 g/cm(exp 2), Al equivalent). The maximum dose rate on EURECA (1.16 mGy/day) was 37% of the maximum measured on LDEF and dose rates at all depths were less than measured on LDEF. The shielding external to the flight canister covered a greater solid angle about the canister than the LDEF experiments.

  14. A Western Pacific Hotspot?

    NASA Astrophysics Data System (ADS)

    MacPherson, C. G.; Hall, R.

    2002-12-01

    The petrology of volcanic rocks from the St. Andrew Strait and helium isotope ratios of backarc lavas from the Manus Basin have been used to propose the existence of an active hotspot beneath the eastern Bismarck Sea [1,2]. The possible influence of this hotspot can be assessed by mapping its present location onto a plate tectonic reconstruction of the western Pacific [3,4]. During the Middle Eocene the nascent Izu-Bonin-Mariana (IBM) arc lay above the hotspot. The volume of magma emplaced at the IBM arc at that time substantially exceeds the average magma production rate for mature island arcs. Furthermore, the ultramafic (boninitic) character of much of this magmatism requires elevated temperatures in the mantle. The geochemistry of contemporaneous magmatism in the backarc resembles melts usually found at ocean islands and much of the backarc region experienced significant uplift at that time. All of these features can be explained by the influx of hot, buoyant, chemically distinct mantle beneath the IBM and its hinterland. The plates lying above the hotspot during the later Eocene were subsequently subducted, but plate reconstruction suggests that during the Oligo-Miocene it was crossed by parts of the Caroline Plate where the Euripik Rise is found. This is an aseismic rise that possesses the geophysical characteristics of thickened oceanic crust formed by excess, basaltic magmatism and is the type of structure that would result from the passage of relatively young oceanic lithosphere over a mantle hotspot. Plate reconstruction for the western Pacific predicts a hotspot trail that is consistent with the Middle Eocene and Oligo-Miocene geology of the IBM and Caroline Plates, respectively. Parts of the trail have been disrupted by subsequent sea-floor spreading or lost through subduction but the remaining vestiges are consistent with the action of a thermal anomaly throughout much of the Cenozoic. More speculatively, the difference in buoyancy between the IBM

  15. Radiation exposure of LDEF: Initial results

    NASA Technical Reports Server (NTRS)

    Benton, E. V.; Frank, A. L.; Benton, E. R.; Csige, I.; Parnell, T. A.; Watts, John W., Jr.

    1991-01-01

    Initial results from Long Duration Exposure Facility (LDEF) include radiation detector measurements from four experiments; P0006, P0004, M0004, and A0015. The detectors were located on both the leading and trailing edges of the orbiter and also at the Earthside end. This allowed the directional dependence of the incoming radiation to be measured. Total absorbed doses from thermoluminescent detectors (TLDs) verified the predicted spatial east-west dose dependence of a factor of approx. 2.5, due to trapped proton anisotropy in the South Atlantic Anomaly (SAA). On the trailing edge of the orbiter, a range of doses from 664 to 291 rad were measured under nominal shielding of 0.42 to 8.45 g/sq cm. A second set of detectors near this locations results are also given. On the leading edge, doses of 258 to 210 rad were found under shielding of 1.25 to 2.48 g/sq cm. Initial charged particle LET (linear energy transfer) spectra, fluxes, doses, and dose equivalents, for LET in H2O greater than or = 5 keV/micron, were measured with plastic nuclear track detectors located in the four experiments. Also, preliminary data on low energy neutrons were obtained from detectors containing (6)LiF foils.

  16. Radiation exposure of LDEF: Initial results

    NASA Technical Reports Server (NTRS)

    Benton, E. V.; Frank, A. L.; Benton, E. R.; Csige, I.; Parnell, T. A.; Watts, John W., Jr.

    1991-01-01

    Initial results from Long Duration Exposure Facility (LDEF) include radiation detector measurements from four experiments; P0006, P0004, M0004, and A0015. The detectors were located on both the leading and trailing edges of the orbiter and also at the Earthside end. This allowed the directional dependence of the incoming radiation to be measured. Total absorbed doses from thermoluminescent detectors (TLDs) verified the predicted spatial east-west dose dependence of a factor of approx. 2.5, due to trapped proton anisotropy in the South Atlantic Anomaly (SAA). On the trailing edge of the orbiter, a range of doses from 664 to 291 rad were measured under nominal shielding of 0.42 to 8.45 g/sq cm. A second set of detectors near this locations results are also given. On the leading edge, doses of 258 to 210 rad were found under shielding of 1.25 to 2.48 g/sq cm. Initial charged particle LET (linear energy transfer) spectra, fluxes, doses, and dose equivalents, for LET in H2O greater than or = 5 keV/micron, were measured with plastic nuclear track detectors located in the four experiments. Also, preliminary data on low energy neutrons were obtained from detectors containing (6)LiF foils.

  17. Radiation exposure of LDEF: Initial results

    NASA Technical Reports Server (NTRS)

    Benton, E. V.; Frank, A. L.; Benton, E. R.; Csige, I.; Parnell, T. A.; Watts, J. W., Jr.

    1992-01-01

    Initial results from LDEF include radiation detector measurements from four experiments, P0006, P0004, M0004, and A0015. The detectors were located on both the leading and trailing edges of the orbiter and also on the Earthside end. This allowed the directional dependence of the incoming radiation to be measured. Total absorbed doses from thermoluminescent detectors (TLDs) verified the predicted spatial east-west dose ratio dependence of a factor approx. 2.5, due to trapped proton anisotropy in the South Atlantic Anomaly. On the trailing edge of the orbiter a range of doses from 6.64 to 2.91 Gy were measured under Al equivalent shielding of 0.42 to 1.11 g/sq cm. A second set of detectors near this location yielded doses of 6.48 to 2.66 Gy under Al equivalent shielding of 0.48 to 15.4 g/sq cm. On the leading edge, doses of 2.58 to 2.10 Gy were found under Al equivalent shielding of 1.37 to 2.90 g/sq cm. Initial charged particle LET (linear energy transfer) spectra, fluxes, doses and dose equivalents, for LET in H2O greater than or = 8 keV/micron, were measured with plastic nuclear track detectors (PNTDs) located in two experiments. Also preliminary data on low energy neutrons were obtained from detectors containing (6)LiF foils.

  18. New Tests of the Fixed Hotspot Approximation

    NASA Astrophysics Data System (ADS)

    Gordon, R. G.; Andrews, D. L.; Horner-Johnson, B. C.; Kumar, R. R.

    2005-05-01

    We present new methods for estimating uncertainties in plate reconstructions relative to the hotspots and new tests of the fixed hotspot approximation. We find no significant motion between Pacific hotspots, on the one hand, and Indo-Atlantic hotspots, on the other, for the past ~ 50 Myr, but large and significant apparent motion before 50 Ma. Whether this motion is truly due to motion between hotspots or alternatively due to flaws in the global plate motion circuit can be tested with paleomagnetic data. These tests give results consistent with the fixed hotspot approximation and indicate significant misfits when a relative plate motion circuit through Antarctica is employed for times before 50 Ma. If all of the misfit to the global plate motion circuit is due to motion between East and West Antarctica, then that motion is 800 ± 500 km near the Ross Sea Embayment and progressively less along the Trans-Antarctic Mountains toward the Weddell Sea. Further paleomagnetic tests of the fixed hotspot approximation can be made. Cenozoic and Cretaceous paleomagnetic data from the Pacific plate, along with reconstructions of the Pacific plate relative to the hotspots, can be used to estimate an apparent polar wander (APW) path of Pacific hotspots. An APW path of Indo-Atlantic hotspots can be similarly estimated (e.g. Besse & Courtillot 2002). If both paths diverge in similar ways from the north pole of the hotspot reference frame, it would indicate that the hotspots have moved in unison relative to the spin axis, which may be attributed to true polar wander. If the two paths diverge from one another, motion between Pacific hotspots and Indo-Atlantic hotspots would be indicated. The general agreement of the two paths shows that the former is more important than the latter. The data require little or no motion between groups of hotspots, but up to ~10 mm/yr of motion is allowed within uncertainties. The results disagree, in particular, with the recent extreme interpretation of

  19. Pacemaker failure resulting from radiation damage

    SciTech Connect

    Quertermous, T.; Megahy, M.S.; Das Gupta, D.S.; Griem, M.L.

    1983-07-01

    The authors present a case of radiation-induced pacemaker failure. After 2000 rad (20 Gy) of photon irradiation for metastatic bronchogenic carcinoma, the pulse generator circuitry failed, producing a runaway rhythm. This suggests that present pacemaker circuitry may be more susceptible to irradiation than previously believed, and that even modest radiation doses can induce life-threatening arrhythmias.

  20. HotSpot Health Physics Codes

    SciTech Connect

    Homann, S. G.

    2013-04-18

    The HotSpot Health Physics Codes were created to provide emergency response personnel and emergency planners with a fast, field-portable set of software tools for evaluating insidents involving redioactive material. The software is also used for safety-analysis of facilities handling nuclear material. HotSpot provides a fast and usually conservative means for estimation the radiation effects associated with the short-term (less than 24 hours) atmospheric release of radioactive materials.

  1. Hybrid hotspot detection using regression model and lithography simulation

    NASA Astrophysics Data System (ADS)

    Kimura, Taiki; Matsunawa, Tetsuaki; Nojima, Shigeki; Pan, David Z.

    2016-03-01

    As minimum feature sizes shrink, unexpected hotspots appear on wafers. Therefore, it is important to detect and fix these hotspots at design stage to reduce development time and manufacturing cost. Currently, as the most accurate approach, lithography simulation is widely used to detect such hotspots. However, it is known to be time-consuming. This paper proposes a novel aerial image synthesizing method using regression and minimum lithography simulation for only hotspot detection. Experimental results show hotspot detection on the proposed method is equivalent compared with the results on the conventional hotspot detection method which uses only lithography simulation with much less computational cost.

  2. Evolution of a hotspot genus: geographic variation in speciation and extinction rates in Banksia (Proteaceae)

    PubMed Central

    2013-01-01

    Background Hotspots of angiosperm species richness and endemism in Mediterranean-climate regions are among the most striking, but least well-understood, geographic patterns of biodiversity. Recent studies have emphasized the importance of rapid diversification within hotspots, compared to non-hotspot regions, as a major contributor to these patterns. We constructed the first near-complete phylogeny of Banksia (Proteaceae) to test whether diversification rates have differed between lineages confined to the southwest Australian hotspot and those found throughout southern, eastern and northern Australia. We then tested for variation in diversification rates among the bioclimatic zones within the southwest hotspot itself. Results Although Banksia species richness in the southwest is ten times that of the rest of the continent, we find little evidence for more rapid diversification in the southwest, although this result is inconclusive. However, we find firmer support for substantial rate variation within the southwest hotspot, with more rapid diversification in the semi-arid heaths and shrublands, compared to the high-rainfall forests. Most of the Banksia diversity of the southwest appears to be generated in the heaths and shrublands, with a high migration rate out of this zone boosting diversity of the adjacent forest zone. Conclusions The geographic pattern of diversification in Banksia appears more complex than can be characterized by a simple hotspot vs. non-hotspot comparison, but in general, these findings contrast with the view that the high diversity of Mediterranean hotspots is underpinned by rapid radiations. Steady accumulation of species at unexceptional rates, but over long periods of time, may also have contributed substantially to the great botanical richness of these regions. PMID:23957450

  3. Earth Radiation Budget Experiment - Preliminary seasonal results

    NASA Technical Reports Server (NTRS)

    Barkstrom, Bruce R.; Harrison, Edwin F.; Lee, Robert B., III

    1990-01-01

    Over the previous four years the Earth Radiation Budget Experiment (ERBE) instruments have been gathering data on two satellites, the Earth Radiation Budget Satellite and the the operational NOAA-9 satellite. The ERBE science team recently completed the validation of an initial sampling of these data involving intensive examination of data in four months during 1985 and 1986. The data being placed in the National Space Science Data Center to acquaint the scientific community with their availability are discussed. The ERBE archival data products are also presented.

  4. Results from the Martian Radiation Environment Experiment

    NASA Astrophysics Data System (ADS)

    Zeitlin, C.; Cleghorn, T. F.; Cucinotta, F. A.; Saganti, P.

    2003-12-01

    Ionizing radiation in space presents a potentially serious health hazard to astronauts on long-duration missions outside the geomagnetosphere. As a precursor to possible human exploration, the Martian Radiation Environment Experiment, MARIE, is returning the first detailed radiation data from Mars. MARIE is designed to measure the nearly constant flux of energetic Galactic Cosmic Rays (GCR) and intermittent Solar Particle Events (SPE). Despite considerable uncertainties in the normalization of MARIE data, comparisons to model calculations show good agreement, well within the estimated errors. The radiation dose equivalent on Mars from GCR is predicted to be 0.2 - 0.3 Sieverts/yr. (This is approximately 1000 times higher than the cosmic ray dose received on Earth.) In Mars orbit, over the first 16 months of operation, MARIE data show an annual dose equivalent of 0.4 +- 0.1 Sv/yr. That the measured rate is higher than the calculation is expected, since in orbit there is a contribution from low-energy particles that do not survive transport through the atmosphere. Additionally, SPE during this period have contributed about 0.04 Sv/yr to the average annual dose equivalent, a figure that can vary substantially over the course of the solar cycle. The implications of these data for human exploration will be discussed.

  5. Spectral investigation of hot-spot and cavity resonance effects on the terahertz radiation emitted from high-Tc superconducting Bi2Sr2CaCu2O8+δ single crystal mesa structures

    NASA Astrophysics Data System (ADS)

    Kadowaki, Kazuo; Watanabe, Chiharu; Minami, Hidetoshi; Yamamoto, Takashi; Kashiwagi, Takanari; Klemm, Richard

    2014-03-01

    Terahertz (THz) electromagnetic radiation emitted from high-Tc superconducting Bi2Sr2CaCu2O8+δ mesa structures in the case of single mesa and series-connected mesas is investigated by the FTIR spectroscopic technique while observing its temperature distribution simultaneously by a SiC photoluminescence technique. Changing the bias level, sudden jumps of the hot-spot position were clearly observed. Although the radiation intensity changes drastically associated with the jump of the hot spot position, the frequency is unaffected as long as the voltage per junction is kept constant. Since the frequency of the intense radiation satisfies the cavity resonance condition, we confirmed that the cavity resonance is of primarily importance for the synchronization of whole intrinsic Josephson junctions in the mesa for high power radiation. This work was supported in part by the Grant-in-Aid for challenging Exploratory Research, the Ministry of Education, Culture, Sports, Science & Technology (MEXT).

  6. Results from the Martian Radiation Environment Experiment

    NASA Astrophysics Data System (ADS)

    Zeitlin, C.; Cleghorn, T.; Cucinotta, F.; Saganti, P.; Andersen, V.; Lee, K.; Pinsky, L.; Atwell, W.; Turner, R.

    2003-04-01

    One of the three science instruments aboard the 2001 Mars Odyssey spacecraft is the Martian Radiation Environment Experiment, MARIE. The experiment consists of a stack of silicon detectors, augmented by a Cerenkov detector. MARIE is designed to measure a portion of the particle spectrum of the Galactic Cosmic Rays (GCR), as well as the high fluxes of low-energy protons (energies less than about 100 MeV) that are intermittently produced by active regions on the sun in Solar Particle Events (SPE). MARIE is providing the first detailed information about the radiation environment near Mars. The silicon detectors record the ionization energy loss of incident particles. For the particle energies measured by MARIE, the energy depositions in silicon are, to a good approximation, proportional to radiation dose in tissue. Thus pulse-height data from the silicon detectors provide a reliable measurement of the dose. Preliminary comparisons with the HZETRN model of the GCR show good agreement during solar quiet times, although more work is needed to adjust the model for some of the limitations of the detector. Also, several solar particle events of considerable interest have been observed. Detailed comparisons of these events as seen at Mars and as seen by near-Earth detectors such as GOES-8 provide information about the CME-driven shockwaves that accelerate the particles.

  7. Evaluating Temporal Consistency in Marine Biodiversity Hotspots.

    PubMed

    Piacenza, Susan E; Thurman, Lindsey L; Barner, Allison K; Benkwitt, Cassandra E; Boersma, Kate S; Cerny-Chipman, Elizabeth B; Ingeman, Kurt E; Kindinger, Tye L; Lindsley, Amy J; Nelson, Jake; Reimer, Jessica N; Rowe, Jennifer C; Shen, Chenchen; Thompson, Kevin A; Heppell, Selina S

    2015-01-01

    With the ongoing crisis of biodiversity loss and limited resources for conservation, the concept of biodiversity hotspots has been useful in determining conservation priority areas. However, there has been limited research into how temporal variability in biodiversity may influence conservation area prioritization. To address this information gap, we present an approach to evaluate the temporal consistency of biodiversity hotspots in large marine ecosystems. Using a large scale, public monitoring dataset collected over an eight year period off the US Pacific Coast, we developed a methodological approach for avoiding biases associated with hotspot delineation. We aggregated benthic fish species data from research trawls and calculated mean hotspot thresholds for fish species richness and Shannon's diversity indices over the eight year dataset. We used a spatial frequency distribution method to assign hotspot designations to the grid cells annually. We found no areas containing consistently high biodiversity through the entire study period based on the mean thresholds, and no grid cell was designated as a hotspot for greater than 50% of the time-series. To test if our approach was sensitive to sampling effort and the geographic extent of the survey, we followed a similar routine for the northern region of the survey area. Our finding of low consistency in benthic fish biodiversity hotspots over time was upheld, regardless of biodiversity metric used, whether thresholds were calculated per year or across all years, or the spatial extent for which we calculated thresholds and identified hotspots. Our results suggest that static measures of benthic fish biodiversity off the US West Coast are insufficient for identification of hotspots and that long-term data are required to appropriately identify patterns of high temporal variability in biodiversity for these highly mobile taxa. Given that ecological communities are responding to a changing climate and other

  8. Evaluating Temporal Consistency in Marine Biodiversity Hotspots

    PubMed Central

    Barner, Allison K.; Benkwitt, Cassandra E.; Boersma, Kate S.; Cerny-Chipman, Elizabeth B.; Ingeman, Kurt E.; Kindinger, Tye L.; Lindsley, Amy J.; Nelson, Jake; Reimer, Jessica N.; Rowe, Jennifer C.; Shen, Chenchen; Thompson, Kevin A.; Heppell, Selina S.

    2015-01-01

    With the ongoing crisis of biodiversity loss and limited resources for conservation, the concept of biodiversity hotspots has been useful in determining conservation priority areas. However, there has been limited research into how temporal variability in biodiversity may influence conservation area prioritization. To address this information gap, we present an approach to evaluate the temporal consistency of biodiversity hotspots in large marine ecosystems. Using a large scale, public monitoring dataset collected over an eight year period off the US Pacific Coast, we developed a methodological approach for avoiding biases associated with hotspot delineation. We aggregated benthic fish species data from research trawls and calculated mean hotspot thresholds for fish species richness and Shannon’s diversity indices over the eight year dataset. We used a spatial frequency distribution method to assign hotspot designations to the grid cells annually. We found no areas containing consistently high biodiversity through the entire study period based on the mean thresholds, and no grid cell was designated as a hotspot for greater than 50% of the time-series. To test if our approach was sensitive to sampling effort and the geographic extent of the survey, we followed a similar routine for the northern region of the survey area. Our finding of low consistency in benthic fish biodiversity hotspots over time was upheld, regardless of biodiversity metric used, whether thresholds were calculated per year or across all years, or the spatial extent for which we calculated thresholds and identified hotspots. Our results suggest that static measures of benthic fish biodiversity off the US West Coast are insufficient for identification of hotspots and that long-term data are required to appropriately identify patterns of high temporal variability in biodiversity for these highly mobile taxa. Given that ecological communities are responding to a changing climate and other

  9. Latitudinal Shift of the Hawaiian Hotspot: Motion Relative to Other Hotspots or True Polar Wander?

    NASA Astrophysics Data System (ADS)

    Gordon, R. G.; Horner-Johnson, B. C.

    2004-12-01

    Recent results from deep sea drilling confirm a large southward drift of the Hawaiian hotspot since Campanian and Maastrichtian time (ca. 70 to 83 Ma), as was previously found from prior paleomagnetic results from drilling (Kono, 1980; Jackson et al. 1980), from skewness analysis of Pacific magnetic anomalies (Gordon 1982, Petronotis & Gordon 1989, 1999; Petronotis et al. 1992, 1994; Acton & Gordon, 1991; Vasas et al. 1994; Horner-Johnson & Gordon 2003), and from other paleomagnetic and paleolatitude data (Gordon & Cape 1981; Sager & Bleil 1987). This southward drift could have been the result of motion of the Hawaiian hotspot relative to some other hotspots, or of true polar wander, or of both. Tarduno et al. (2003) have recently presented an extreme interpretation of these results as being entirely due to southward motion of the Hawaiian hotspot through the mantle. Here we show that this extreme interpretation is not supported by available data. While the Pacific plate paleomagnetic data are sufficient to show that the Hawaiian hotspot has moved southward relative to the spin axis, alone they cannot be used to demonstrate motion relative to the mantle or relative to other hotspots. To do so, coeval paleomagnetic poles are needed from the continents bordering the Atlantic and Indian Oceans. Here we show that few, if any, of the coeval paleomagnetic poles from the continents incorporated into widely used reference paths pass minimum reliability criteria. Thus, the inference of rapid motion of the Hawaiian hotspot relative to the mantle is surely premature and probably incorrect. We further show that other earlier studies purporting to show motion between hotspots from paleomagnetic data are now invalid because of revisions to paleomagnetic poles from the continents or because of flaws in analysis. Updated paleomagnetic analyses indicate that little motion has occurred between Pacific hotspots and non-Pacific hotspots. Instead, available data are consistent with the

  10. ASAR Revealing Hot-Spots of Internal Solitary Waves in the Arctic: Preliminary Results for the Laptev Sea

    NASA Astrophysics Data System (ADS)

    Kozlov, Igor E.; Zubkova, Evgenia V.; Kudryavtsev, Vladimir N.

    2016-08-01

    In this work we present first preliminary results of internal solitary waves' observations in the Laptev Sea using a set of ENVISAT Advanced Synthetic Aperture Radar (ASAR) images. Analysis of 354 ASAR images acquired between May-October 2011 helped to identify 91 distinct patterns of oceanic internal waves and reveal main regions of their occurrence. As found, the primary regions of IW observations are located north-west to Arctic Cape, over the continental slope regions east to Maly Taymyr Island and north-west to Kotelny Island, and east to the Gulf of Khatanga. Detailed maps of main internal wave parameters are presented, and some features of their propagation and implications for the vertical mixing in the Laptev Sea are also discussed.

  11. Recent Radiation Test Results for Power MOSFETs

    NASA Technical Reports Server (NTRS)

    Lauenstein, Jean-Marie; Topper, Alyson D.; Casey, Megan C.; Wilcox, Edward P.; Phan, Anthony M.; Kim, Hak S.; LaBel, Kenneth A.

    2013-01-01

    Single-event effect (SEE) and total ionizing dose (TID) test results are presented for various hardened and commercial power metal-oxide-semiconductor field effect transistors (MOSFETs), including vertical planar, trench, superjunction, and lateral process designs.

  12. Predictive aging results in radiation environments

    NASA Astrophysics Data System (ADS)

    Gillen, Kenneth T.; Clough, Roger L.

    1993-06-01

    We have previously derived a time-temperature-dose rate superposition methodology, which, when applicable, can be used to predict polymer degradation versus dose rate, temperature and exposure time. This methodology results in predictive capabilities at the low dose rates and long time periods appropriate, for instance, to ambient nuclear power plant environments. The methodology was successfully applied to several polymeric cable materials and then verified for two of the materials by comparisons of the model predictions with 12 year, low-dose-rate aging data on these materials from a nuclear environment. In this paper, we provide a more detailed discussion of the methodology and apply it to data obtained on a number of additional nuclear power plant cable insulation (a hypalon, a silicone rubber and two ethylene-tetrafluoroethylenes) and jacket (a hypalon) materials. We then show that the predicted, low-dose-rate results for our materials are in excellent agreement with long-term (7-9 year) low-dose-rate results recently obtained for the same material types actually aged under bnuclear power plant conditions. Based on a combination of the modelling and long-term results, we find indications of reasonably similar degradation responses among several different commercial formulations for each of the following "generic" materials: hypalon, ethylene-tetrafluoroethylene, silicone rubber and PVC. If such "generic" behavior can be further substantiated through modelling and long-term results on additional formulations, predictions of cable life for other commercial materials of the same generic types would be greatly facilitated.

  13. A Research Agenda for Radiation Oncology: Results of the Radiation Oncology Institute's Comprehensive Research Needs Assessment

    SciTech Connect

    Jagsi, Reshma; Bekelman, Justin E.; Brawley, Otis W.; Deasy, Joseph O.; Le, Quynh-Thu; Michalski, Jeff M.; Movsas, Benjamin; Thomas, Charles R.; Lawton, Colleen A.; Lawrence, Theodore S.; Hahn, Stephen M.

    2012-10-01

    Purpose: To promote the rational use of scarce research funding, scholars have developed methods for the systematic identification and prioritization of health research needs. The Radiation Oncology Institute commissioned an independent, comprehensive assessment of research needs for the advancement of radiation oncology care. Methods and Materials: The research needs assessment used a mixed-method, qualitative and quantitative social scientific approach, including structured interviews with diverse stakeholders, focus groups, surveys of American Society for Radiation Oncology (ASTRO) members, and a prioritization exercise using a modified Delphi technique. Results: Six co-equal priorities were identified: (1) Identify and develop communication strategies to help patients and others better understand radiation therapy; (2) Establish a set of quality indicators for major radiation oncology procedures and evaluate their use in radiation oncology delivery; (3) Identify best practices for the management of radiation toxicity and issues in cancer survivorship; (4) Conduct comparative effectiveness studies related to radiation therapy that consider clinical benefit, toxicity (including quality of life), and other outcomes; (5) Assess the value of radiation therapy; and (6) Develop a radiation oncology registry. Conclusions: To our knowledge, this prioritization exercise is the only comprehensive and methodologically rigorous assessment of research needs in the field of radiation oncology. Broad dissemination of these findings is critical to maximally leverage the impact of this work, particularly because grant funding decisions are often made by committees on which highly specialized disciplines such as radiation oncology are not well represented.

  14. Bayesian inference of shared recombination hotspots between humans and chimpanzees.

    PubMed

    Wang, Ying; Rannala, Bruce

    2014-12-01

    Recombination generates variation and facilitates evolution. Recombination (or lack thereof) also contributes to human genetic disease. Methods for mapping genes influencing complex genetic diseases via association rely on linkage disequilibrium (LD) in human populations, which is influenced by rates of recombination across the genome. Comparative population genomic analyses of recombination using related primate species can identify factors influencing rates of recombination in humans. Such studies can indicate how variable hotspots for recombination may be both among individuals (or populations) and over evolutionary timescales. Previous studies have suggested that locations of recombination hotspots are not conserved between humans and chimpanzees. We made use of the data sets from recent resequencing projects and applied a Bayesian method for identifying hotspots and estimating recombination rates. We also reanalyzed SNP data sets for regions with known hotspots in humans using samples from the human and chimpanzee. The Bayes factors (BF) of shared recombination hotspots between human and chimpanzee across regions were obtained. Based on the analysis of the aligned regions of human chromosome 21, locations where the two species show evidence of shared recombination hotspots (with high BFs) were identified. Interestingly, previous comparative studies of human and chimpanzee that focused on the known human recombination hotspots within the β-globin and HLA regions did not find overlapping of hotspots. Our results show high BFs of shared hotspots at locations within both regions, and the estimated locations of shared hotspots overlap with the locations of human recombination hotspots obtained from sperm-typing studies.

  15. Warfare in biodiversity hotspots.

    PubMed

    Hanson, Thor; Brooks, Thomas M; Da Fonseca, Gustavo A B; Hoffmann, Michael; Lamoreux, John F; Machlis, Gary; Mittermeier, Cristina G; Mittermeier, Russell A; Pilgrim, John D

    2009-06-01

    Conservation efforts are only as sustainable as the social and political context within which they take place. The weakening or collapse of sociopolitical frameworks during wartime can lead to habitat destruction and the erosion of conservation policies, but in some cases, may also confer ecological benefits through altered settlement patterns and reduced resource exploitation. Over 90% of the major armed conflicts between 1950 and 2000 occurred within countries containing biodiversity hotspots, and more than 80% took place directly within hotspot areas. Less than one-third of the 34 recognized hotspots escaped significant conflict during this period, and most suffered repeated episodes of violence. This pattern was remarkably consistent over these 5 decades. Evidence from the war-torn Eastern Afromontane hotspot suggests that biodiversity conservation is improved when international nongovernmental organizations support local protected area staff and remain engaged throughout the conflict. With biodiversity hotspots concentrated in politically volatile regions, the conservation community must maintain continuous involvement during periods of war, and biodiversity conservation should be incorporated into military, reconstruction, and humanitarian programs in the world's conflict zones.

  16. Canopy hot-spot as crop identifier

    SciTech Connect

    Gerstl, S.A.W.; Simmer, C.; Powers, B.J.

    1986-05-01

    Illuminating any reflective rough or structured surface by a directional light source results in an angular reflectance distribution that shows a narrow peak in the direction of retro-reflection. This is called the Heiligenschein or hot-spot of vegetation canopies and is caused by mutual shading of leaves. The angular intensity distribution of the hot-spot, its brightness and slope, are therefore indicators of the plant's geometry. We propose the use of hot-spot characteristics as crop identifiers in satellite remote sensing because the canopy hot-spot carries information about plant stand architecture that is more distinctive for different plant species than, for instance, their spectral reflectance characteristics. A simple three-dimensional Monte Carlo/ray tracing model and an analytic two-dimensional model are developed to estimate the angular distribution of the hot-spot as a function of the size of the plant leaves. The results show that the brightness-distribution and slope of the hot-spot change distinctively for different leaf sizes indicating a much more peaked maximum for the smaller leaves.

  17. Hotspot swells revisited

    NASA Astrophysics Data System (ADS)

    King, Scott D.; Adam, Claudia

    2014-10-01

    The first attempts to quantify the width and height of hotspot swells were made more than 30 years ago. Since that time, topography, ocean-floor age, and sediment thickness datasets have improved considerably. Swell heights and widths have been used to estimate the heat flow from the core-mantle boundary, constrain numerical models of plumes, and as an indicator of the origin of hotspots. In this paper, we repeat the analysis of swell geometry and buoyancy flux for 54 hotspots, including the 37 considered by Sleep (1990) and the 49 considered by Courtillot et al. (2003), using the latest and most accurate data. We are able to calculate swell geometry for a number of hotspots that Sleep was only able to estimate by comparison with other swells. We find that in spite of the increased resolution in global bathymetry models there is significant uncertainty in our calculation of buoyancy fluxes due to differences in our measurement of the swells’ width and height, the integration method (volume integration or cross-sectional area), and the variations of the plate velocities between HS2-Nuvel1a (Gripp and Gordon, 1990) and HS3-Nuvel1a (Gripp and Gordon, 2002). We also note that the buoyancy flux for Pacific hotspots is in general larger than for Eurasian, North American, African and Antarctic hotspots. Considering that buoyancy flux is linearly related to plate velocity, we speculate that either the calculation of buoyancy flux using plate velocity over-estimates the actual vertical flow of material from the deep mantle or that convection in the Pacific hemisphere is more vigorous than the Atlantic hemisphere.

  18. Non-Scanning Radiometer Results for Earth Radiation Budget Investigations

    NASA Technical Reports Server (NTRS)

    Smith, G. Louis; Green, Richard N.; Lee, Robert B., III; Bess, T. Dale; Rutan, David

    1992-01-01

    The Earth Radiation Budget Experiment (ERBE) included non-scanning radiometers (Luther, 1986) flown aboard a dedicated mission of Earth Radiation Budget Satellite, and the NOAA-9 and -10 operational meteorological spacecraft (Barkstrom and Smith, 1986). The radiometers first began providing Earth radiation budget data in November 1984 and have remained operational, providing a record of nearly 8 years of data to date for researchers. Although they do not produce measurements with the resolution given by the scanning radiometers, the results from the non-scanning radiometers are extremely useful for climate research involving long-term radiation data sets. This paper discusses the non-scanning radiometers, their stability, the method of analyzing the data, and brief scientific results from the data.

  19. The effects of acid leaching on 40Ar/39Ar age dating results using samples from the Walvis Ridge hotspot trail

    NASA Astrophysics Data System (ADS)

    Klath, J. F.; Koppers, A. A.; Heaton, D. E.; Schnur, S.

    2013-12-01

    In this study we systematically explore how acid leaching can be used to reduce the negative effects of seawater alteration on the 40Ar/39Ar age dating of submarine basalts. Koppers et al (2000) showed that acid leaching of groundmass samples generated more consistent ages as well as ages more concordant with phenocrystic mineral phases, compared to samples that were left untreated. By studying the effects of progressively increasing the strength and length of acid treatment, we will show how acid leaching of groundmass separates reduces alteration while leaving the initial eruption signature intact. Samples were chosen from the Walvis ridge hotspot trail in the southeast Atlantic. Three samples were selected based on degree and style of alteration. Two samples (basalt and basaltic andesite) appear highly altered in thin section. The basalt contains diffuse iddingsite alteration that is pervasive throughout the groundmass. The basaltic andesite displays focused secondary mineral phases within and around abundant vesicles. The third sample, a trachyte, shows relatively minor degrees of alteration in thin section. These groundmass separates were divided into four splits and treated with a progressively stronger acid and for longer duration. One split from each rock was left untreated to act as a baseline. Of the other three splits from each sample, one was treated with a mild leach (1N HCl and 1N HNO3), one a strong leach (1N HCl, 1N HNO3, 6N HCl, and 3N HNO3), and lastly the strong leach performed twice. The samples were then handpicked to remove any remaining visible alteration. The untreated samples were picked as well, removing the most distinctly altered grains. All splits were analyzed by electron microprobe, x-ray fluorescence (XRF) and the incremental heating 40Ar/39Ar dating method. We will report on the results of an image analysis of microprobe backscatter images and elemental maps taken of individual groundmass grains. This analysis will show the location

  20. Concentrator hot-spot testing, phase 1

    NASA Technical Reports Server (NTRS)

    Gonzalez, C. C.

    1987-01-01

    Results of a study to determine the hot-spot susceptibility of concentrator cells, to provide a hot-spot qualification test for concentrator modules, and to provide guidelines for reducing hot-spot susceptibility are presented. Hot-spot heating occurs in a photovoltaic module when the short-circuit current of a cell is lower than the string operating current forcing the cell into reverse bias with a concurrent power dissipation. Although the basis for the concentrator module hot-spot qualification test is the test developed for flat-plate modules, issues, such as providing cell illumination, introduce additional complexities into the testing procedure. The same general guidelines apply for protecting concentrator modules from hot-spot stressing as apply to flat-plate modules. Therefore, recommendations are made on the number of bypass diodes required per given number of series cells per module or source circuit. In addition, a new method for determining the cell temperature in the laboratory or in the field is discussed.

  1. Acute Radiation Effects Resulting from Exposure to Solar Particle Event-Like Radiation

    NASA Astrophysics Data System (ADS)

    Kennedy, Ann; Cengel, Keith

    2012-07-01

    A major solar particle event (SPE) may place astronauts at significant risk for the acute radiation syndrome (ARS), which may be exacerbated when combined with other space flight stressors, such that the mission or crew health may be compromised. The National Space Biomedical Research Institute (NSBRI) Center of Acute Radiation Research (CARR) is focused on the assessment of risks of adverse biological effects related to the ARS in animal models exposed to space flight stressors combined with the types of radiation expected during an SPE. As part of this program, FDA-approved drugs that may prevent and/or mitigate ARS symptoms are being evaluated. The CARR studies are focused on the adverse biological effects resulting from exposure to the types of radiation, at the appropriate energies, doses and dose-rates, present during an SPE (and standard reference radiations, gamma rays or electrons). The ARS is a phased syndrome which often includes vomiting and fatigue. Other acute adverse biologic effects of concern are the loss of hematopoietic cells, which can result in compromised bone marrow and immune cell functions. There is also concern for skin damage from high SPE radiation doses, including burns, and resulting immune system dysfunction. Using 3 separate animal model systems (ferrets, mice and pigs), the major ARS biologic endpoints being evaluated are: 1) vomiting/retching and fatigue, 2) hematologic changes (with focus on white blood cells) and immune system changes resulting from exposure to SPE radiation with and without reduced weightbearing conditions, and 3) skin injury and related immune system functions. In all of these areas of research, statistically significant adverse health effects have been observed in animals exposed to SPE-like radiation. Countermeasures for the management of ARS symptoms are being evaluated. New research findings from the past grant year will be discussed. Acknowledgements: This research is supported by the NSBRI Center of Acute

  2. Fast dual graph-based hotspot detection

    NASA Astrophysics Data System (ADS)

    Kahng, Andrew B.; Park, Chul-Hong; Xu, Xu

    2006-10-01

    As advanced technologies in wafer manufacturing push patterning processes toward lower-k I subwavelength printing, lithography for mass production potentially suffers from decreased patterning fidelity. This results in generation of many hotspots, which are actual device patterns with relatively large CD and image errors with respect to on-wafer targets. Hotspots can be formed under a variety of conditions such as the original design being unfriendly to the RET that is applied, unanticipated pattern combinations in rule-based OPC, or inaccuracies in model-based OPC. When these hotspots fall on locations that are critical to the electrical performance of a device, device performance and parametric yield can be significantly degraded. Previous rule-based hotspot detection methods suffer from long runtimes for complicated patterns. Also, the model generation process that captures process variation within simulation-based approaches brings significant overheads in terms of validation, measurement and parameter calibration. In this paper, we first describe a novel detection algorithm for hotspots induced by lithographic uncertainty. Our goal is to rapidly detect all lithographic hotspots without significant accuracy degradation. In other words, we propose a filtering method: as long as there are no "false negatives", i.e., we successfully have a superset of actual hotspots, then our method can dramatically reduce the layout area for golden hotspot analysis. The first step of our hotspot detection algorithm is to build a layout graph which reflects pattern-related CD variation. Given a layout L, the layout graph G = (V, E c union E p) consists of nodes V, corner edges E c and proximity edges E p. A face in the layout graph includes several close features and the edges between them. Edge weight can be calculated from a traditional 2-D model or a lookup table. We then apply a three-level hotspot detection: (1) edge-level detection finds the hotspot caused by two close

  3. The Continual Intercomparison of Radiation Codes: Results from Phase I

    NASA Technical Reports Server (NTRS)

    Oreopoulos, Lazaros; Mlawer, Eli; Delamere, Jennifer; Shippert, Timothy; Cole, Jason; Iacono, Michael; Jin, Zhonghai; Li, Jiangnan; Manners, James; Raisanen, Petri; hide

    2011-01-01

    The computer codes that calculate the energy budget of solar and thermal radiation in Global Climate Models (GCMs), our most advanced tools for predicting climate change, have to be computationally efficient in order to not impose undue computational burden to climate simulations. By using approximations to gain execution speed, these codes sacrifice accuracy compared to more accurate, but also much slower, alternatives. International efforts to evaluate the approximate schemes have taken place in the past, but they have suffered from the drawback that the accurate standards were not validated themselves for performance. The manuscript summarizes the main results of the first phase of an effort called "Continual Intercomparison of Radiation Codes" (CIRC) where the cases chosen to evaluate the approximate models are based on observations and where we have ensured that the accurate models perform well when compared to solar and thermal radiation measurements. The effort is endorsed by international organizations such as the GEWEX Radiation Panel and the International Radiation Commission and has a dedicated website (i.e., http://circ.gsfc.nasa.gov) where interested scientists can freely download data and obtain more information about the effort's modus operandi and objectives. In a paper published in the March 2010 issue of the Bulletin of the American Meteorological Society only a brief overview of CIRC was provided with some sample results. In this paper the analysis of submissions of 11 solar and 13 thermal infrared codes relative to accurate reference calculations obtained by so-called "line-by-line" radiation codes is much more detailed. We demonstrate that, while performance of the approximate codes continues to improve, significant issues still remain to be addressed for satisfactory performance within GCMs. We hope that by identifying and quantifying shortcomings, the paper will help establish performance standards to objectively assess radiation code quality

  4. NASA Space Radiation Risk Project: Overview and Recent Results

    NASA Technical Reports Server (NTRS)

    Blattnig, Steve R.; Chappell, Lori J.; George, Kerry A.; Hada, Megumi; Hu, Shaowen; Kidane, Yared H.; Kim, Myung-Hee Y.; Kovyrshina, Tatiana; Norman, Ryan B.; Nounu, Hatem N.; Peterson, Leif E.; Plante, Ianik; Pluth, Janice M.; Ponomarev, Artem L.; Scott Carnell, Lisa A.; Slaba, Tony C.; Sridharan, Deepa; Xu, Xiaojing

    2015-01-01

    The NASA Space Radiation Risk project is responsible for integrating new experimental and computational results into models to predict risk of cancer and acute radiation syndrome (ARS) for use in mission planning and systems design, as well as current space operations. The project has several parallel efforts focused on proving NASA's radiation risk projection capability in both the near and long term. This presentation will give an overview, with select results from these efforts including the following topics: verification, validation, and streamlining the transition of models to use in decision making; relative biological effectiveness and dose rate effect estimation using a combination of stochastic track structure simulations, DNA damage model calculations and experimental data; ARS model improvements; pathway analysis from gene expression data sets; solar particle event probabilistic exposure calculation including correlated uncertainties for use in design optimization.

  5. Yellowstone Hotspot Geodynamics

    NASA Astrophysics Data System (ADS)

    Smith, R. B.; Farrell, J.; Massin, F.; Chang, W.; Puskas, C. M.; Steinberger, B. M.; Husen, S.

    2012-12-01

    The Yellowstone hotspot results from the interaction of a mantle plume with the overriding N. America plate producing a ~300-m high topographic swell centered on the Late Quaternary Yellowstone volcanic field. The Yellowstone area is dominated by earthquake swarms including a deadly M7.3 earthquake, extraordinary high heat flow up to ~40,000 mWm-2, and unprecedented episodes of crustal deformation. Seismic tomography and gravity data reveal a crustal magma reservoir, 6 to 15 km deep beneath the Yellowstone caldera but extending laterally ~20 km NE of the caldera and is ~30% larger than previously hypothesized. Kinematically, deformation of Yellowstone is dominated by regional crustal extension at up to ~0.4 cm/yr but with superimposed decadal-scale uplift and subsidence episodes, averaging ~2 cm/yr from 1923. From 2004 to 2009 Yellowstone experienced an accelerated uplift episode of up to 7 cm/yr whose source is modeled as magmatic recharge of a sill at the top of the crustal magma reservoir at 8-10-km depth. New mantle tomography suggest that Yellowstone volcanism is fed by an upper-mantle plume-shaped low velocity body that is composed of melt "blobs", extending from 80 km to 650 km in depth, tilting 60° NW, but then reversing tilt to ~60° SE to a depth of ~1500 km. Moreover, images of upper mantle conductivity from inversion of MT data reveal a high conductivity annulus around the north side of the plume in the upper mantle to resolved depths of ~300 km. On a larger scale, upper mantle flow beneath the western U.S. is characterized by eastward flow beneath Yellowstone at 5 cm/yr that deflects the plume to the west, and is underlain by a deeper zone of westerly return flow in the lower mantle reversing the deflection of the plume body to the SE. Dynamic modeling of the Yellowstone plume including a +15 m geoid anomaly reveals low excess plume temperatures, up to 150°K, consistent with a weak buoyancy flux of ~0.25 Mg/s. Integrated kinematic modeling of GPS

  6. Identifying species threat hotspots from global supply chains.

    PubMed

    Moran, Daniel; Kanemoto, Keiichiro

    2017-01-04

    Identifying hotspots of species threat has been a successful approach for setting conservation priorities. One important challenge in conservation is that, in many hotspots, export industries continue to drive overexploitation. Conservation measures must consider not just the point of impact, but also the consumer demand that ultimately drives resource use. To understand which species threat hotspots are driven by which consumers, we have developed a new approach to link a set of biodiversity footprint accounts to the hotspots of threatened species on the IUCN Red List of Threatened Species. The result is a map connecting consumption to spatially explicit hotspots driven by production on a global scale. Locating biodiversity threat hotspots driven by consumption of goods and services can help to connect conservationists, consumers, companies and governments in order to better target conservation actions.

  7. High-energy radiation damage in zirconia: Modeling results

    SciTech Connect

    Zarkadoula, E.; Devanathan, R.; Weber, W. J.; Seaton, M. A.; Todorov, I. T.; Nordlund, K.; Dove, M. T.; Trachenko, K.

    2014-02-28

    Zirconia is viewed as a material of exceptional resistance to amorphization by radiation damage, and consequently proposed as a candidate to immobilize nuclear waste and serve as an inert nuclear fuel matrix. Here, we perform molecular dynamics simulations of radiation damage in zirconia in the range of 0.1–0.5 MeV energies with account of electronic energy losses. We find that the lack of amorphizability co-exists with a large number of point defects and their clusters. These, importantly, are largely isolated from each other and therefore represent a dilute damage that does not result in the loss of long-range structural coherence and amorphization. We document the nature of these defects in detail, including their sizes, distribution, and morphology, and discuss practical implications of using zirconia in intense radiation environments.

  8. High-energy radiation damage in zirconia: modeling results

    SciTech Connect

    Zarkadoula, Evangelia; Devanathan, Ram; Weber, William J; Seaton, M; Todorov, I T; Nordlund, Kai; Dove, Martin T; Trachenko, Kostya

    2014-01-01

    Zirconia is viewed as a material of exceptional resistance to amorphization by radiation damage, and consequently proposed as a candidate to immobilize nuclear waste and serve as an inert nuclear fuel matrix. Here, we perform molecular dynamics simulations of radiation damage in zirconia in the range of 0.1-0.5 MeV energies with account of electronic energy losses. We nd that the lack of amorphizability co-exists with a large number of point defects and their clusters. These, importantly, are largely isolated from each other and therefore represent a dilute damage that does not result in the loss of long-range structural coherence and amorphization. We document the nature of these defects in detail, including their sizes, distribution and morphology, and discuss practical implications of using zirconia in intense radiation environments.

  9. High-energy radiation damage in zirconia: Modeling results

    NASA Astrophysics Data System (ADS)

    Zarkadoula, E.; Devanathan, R.; Weber, W. J.; Seaton, M. A.; Todorov, I. T.; Nordlund, K.; Dove, M. T.; Trachenko, K.

    2014-02-01

    Zirconia is viewed as a material of exceptional resistance to amorphization by radiation damage, and consequently proposed as a candidate to immobilize nuclear waste and serve as an inert nuclear fuel matrix. Here, we perform molecular dynamics simulations of radiation damage in zirconia in the range of 0.1-0.5 MeV energies with account of electronic energy losses. We find that the lack of amorphizability co-exists with a large number of point defects and their clusters. These, importantly, are largely isolated from each other and therefore represent a dilute damage that does not result in the loss of long-range structural coherence and amorphization. We document the nature of these defects in detail, including their sizes, distribution, and morphology, and discuss practical implications of using zirconia in intense radiation environments.

  10. High-energy radiation damage in zirconia: modeling results

    SciTech Connect

    Zarkadoula, Eva; Devanathan, Ram; Weber, William J.; Seaton, Michael; Todorov, Ilian; Nordlund, Kai; Dove, Martin T.; Trachenko, Kostya

    2014-02-28

    Zirconia has been viewed as a material of exceptional resistance to amorphization by radiation damage, and was consequently proposed as a candidate to immobilize nuclear waste and serve as a nuclear fuel matrix. Here, we perform molecular dynamics simulations of radiation damage in zirconia in the range of 0.1-0.5 MeV energies with the account of electronic energy losses. We find that the lack of amorphizability co-exists with a large number of point defects and their clusters. These, importantly, are largely disjoint from each other and therefore represent a dilute damage that does not result in the loss of long-range structural coherence and amorphization. We document the nature of these defects in detail, including their sizes, distribution and morphology, and discuss practical implications of using zirconia in intense radiation environments.

  11. Ionizing radiation-induced mutagenesis: radiation studies in Neurospora predictive for results in mammalian cells

    NASA Technical Reports Server (NTRS)

    Evans, H. H.; DeMarini, D. M.

    1999-01-01

    Ionizing radiation was the first mutagen discovered and was used to develop the first mutagenicity assay. In the ensuing 70+ years, ionizing radiation became a fundamental tool in understanding mutagenesis and is still a subject of intensive research. Frederick de Serres et al. developed and used the Neurospora crassa ad-3 system initially to explore the mutagenic effects of ionizing radiation. Using this system, de Serres et al. demonstrated the dependence of the frequency and spectra of mutations induced by ionizing radiation on the dose, dose rate, radiation quality, repair capabilities of the cells, and the target gene employed. This work in Neurospora predicted the subsequent observations of the mutagenic effects of ionizing radiation in mammalian cells. Modeled originally on the mouse specific-locus system developed by William L. Russell, the N. crassa ad-3 system developed by de Serres has itself served as a model for interpreting the results in subsequent systems in mammalian cells. This review describes the primary findings on the nature of ionizing radiation-induced mutagenesis in the N. crassa ad-3 system and the parallel observations made years later in mammalian cells.

  12. Ionizing radiation-induced mutagenesis: radiation studies in Neurospora predictive for results in mammalian cells

    NASA Technical Reports Server (NTRS)

    Evans, H. H.; DeMarini, D. M.

    1999-01-01

    Ionizing radiation was the first mutagen discovered and was used to develop the first mutagenicity assay. In the ensuing 70+ years, ionizing radiation became a fundamental tool in understanding mutagenesis and is still a subject of intensive research. Frederick de Serres et al. developed and used the Neurospora crassa ad-3 system initially to explore the mutagenic effects of ionizing radiation. Using this system, de Serres et al. demonstrated the dependence of the frequency and spectra of mutations induced by ionizing radiation on the dose, dose rate, radiation quality, repair capabilities of the cells, and the target gene employed. This work in Neurospora predicted the subsequent observations of the mutagenic effects of ionizing radiation in mammalian cells. Modeled originally on the mouse specific-locus system developed by William L. Russell, the N. crassa ad-3 system developed by de Serres has itself served as a model for interpreting the results in subsequent systems in mammalian cells. This review describes the primary findings on the nature of ionizing radiation-induced mutagenesis in the N. crassa ad-3 system and the parallel observations made years later in mammalian cells.

  13. New results on radiation effects on human health

    NASA Astrophysics Data System (ADS)

    Spurny, Frantisek; Dachev, Tsvetan

    2009-03-01

    Humans are exposed to ionizing radiation all the time, and it is known that it can induce a variety of harmful biological effects. Consequently, it is necessary to quantitatively assess the level of exposure to this radiation as the basis for estimating risks due to ionization radiation. During the Work Package 2400 of the COST-724/WG-2 action, a number of spacecraft and aircraft experiments have been performed with both active and passive detectors. A large data base has been created. In this contribution we would like to stress the results obtained and their importance in three particular directions: (i) Simultaneous investigation of galactic cosmic rays on aircraft and on the International Space Station (ISS); (ii) Onboard spacecraft neutron contribution as estimated on the basis of the comparison of results measured with MDU/Liulin equipment onboard ISS, foton capsule and a commercial aircraft flying at subsonic altitudes; (iii) Complex analysis of the results of long term measurements onboard a Czech Airlines aircraft. The results obtained are presented, analyzed, and discussed, and their complementary nature is underlined. The contribution represents a version of the Final Report of the Work Package 2400 of the COST-724/WG-2: Radiation Environment of the Earth.

  14. The unusual Samoan hotspot: A "hotspot highway" juxtaposed with a trench

    NASA Astrophysics Data System (ADS)

    Jackson, M. G.; Konter, J. G.; Koppers, A. A.

    2011-12-01

    Oceanic hotspots are fed by (relatively) stationary, upwelling mantle plumes that melt beneath mobile tectonic plates. This mechanism results in the generation of a linear chain of volcanoes exhibiting a clear age progression: the islands and seamounts should be increasingly older with increasing distance from the inferred location of the mantle plume. Located in the southwest Pacific, the Cook-Austral volcanic islands and seamounts were long thought to lack a clear age progression, and it has been argued that the Cook-Austral volcanic chain is an example of a hotspot not fed by a mantle plume. However, work by Chauvel et al (1997) showed that the Cook-Austral volcanoes have been generated by three distinct, co-linear mantle plumes spaced by ~1000 km, resulting in 3 overlapping hotspot tracks. Critically, the volcanoes generated by each hotspot exhibit a clear age progression that emerges from its respective plume. Using plate motion models, the reconstructed tracks of the three Cook-Austral hotspots backtrack through the region of the Pacific plate now occupied by the Samoan hotspot between 10 and 40 Ma (Konter et al., 2008). Owing to the unusual number of hotspots (Samoa is the fourth) that have been hosted in the region, we refer to this corridor of the Pacific plate as the "hotspot highway." The Samoan hotspot is burning through and thus crosscutting the trails of the older Cook-Austral hotspots. Consistent with this hypothesis, Jackson et al. (2010) reported volcanic features from the Cook-Austral hotspots in the Samoan region, including three seamounts and one atoll with geochemical affinities to the Cook-Austral hotspot. The Pacific lithosphere was likely "preconditioned" (metasomatized) by the three Cook-Australs hotspots before the arrival of the Samoan plume into the region, yet geochemical signatures associated with the Cook-Austral hotspot pedigrees are not evident in Samoan shield lavas. However, Samoan rejuvenated lavas exhibit a clear EMI (enriched

  15. Scaling results for the Liquid Sheet Radiator (LSR)

    NASA Technical Reports Server (NTRS)

    Chubb, Donald L.; Calfo, Frederick D.

    1989-01-01

    Surface tension forces at the edges of a thin liquid (approx. 100 micrometers) sheet flow result in a triangularly shaped sheet. Such a geometry is ideal for an external flow radiator. The experimental investigation of such sheet flows was extended to large sheets (width = W = 23.5 cm, length = L approx. = 3.5 m). Experimental L/W results are greater than the calculated results. However, more experimental results are necessary for a complete comparison. The calculated emissivity of a sheet of Dow-Corning 705 silicone oil, which is a low temperature (300 to 400K) candidate for a liquid sheet radiator (LSR), is greater than .8 for sheet thicknesses greater than 100 micrometers.

  16. Hotspot tracks and the early rifting of the Atlantic

    NASA Astrophysics Data System (ADS)

    Jason Morgan, W.

    1983-05-01

    Many hotspot tracks appear to become the locus of later rifting, as though the heat of the hotspot weakens the lithosphere and tens of millions of years later the continents are split along these weakened lines. Examples are the west coast of Greenland-east coast of Labrador (Madeira hotspot), the south coast of Mexico-north coast of Honduras (Guyana hotspot), and the south coast of West Africa-north coast of Brazil (St. Helena hotspot). A modern day analog of a possible future rift is the Snake River Plain, where the North American continent is being "pre-weakened" by the Yellowstone hotspot track. This conclusion is based on reconstructions of the motions of the continents over hotspots for the past 200 million years. The relative motions of the plates are determined from magnetic anomaly isochrons in the oceans and the motion of one plate is chosen ad hoc to best fit the motions of the plates over the hotspots. However, once the motion of this one plate is chosen, the motions of all the other plates are prescribed by the relative motion constraints. In addition to the correlation between the predicted tracks and sites of later continental breakup, exposed continental shields correlate with the tracks. Their exposure may be the result of hotspot induced uplift which has led to erosion of their former platform sediment cover.

  17. Detecting Biosphere anomalies hotspots

    NASA Astrophysics Data System (ADS)

    Guanche-Garcia, Yanira; Mahecha, Miguel; Flach, Milan; Denzler, Joachim

    2017-04-01

    The current amount of satellite remote sensing measurements available allow for applying data-driven methods to investigate environmental processes. The detection of anomalies or abnormal events is crucial to monitor the Earth system and to analyze their impacts on ecosystems and society. By means of a combination of statistical methods, this study proposes an intuitive and efficient methodology to detect those areas that present hotspots of anomalies, i.e. higher levels of abnormal or extreme events or more severe phases during our historical records. Biosphere variables from a preliminary version of the Earth System Data Cube developed within the CAB-LAB project (http://earthsystemdatacube.net/) have been used in this study. This database comprises several atmosphere and biosphere variables expanding 11 years (2001-2011) with 8-day of temporal resolution and 0.25° of global spatial resolution. In this study, we have used 10 variables that measure the biosphere. The methodology applied to detect abnormal events follows the intuitive idea that anomalies are assumed to be time steps that are not well represented by a previously estimated statistical model [1].We combine the use of Autoregressive Moving Average (ARMA) models with a distance metric like Mahalanobis distance to detect abnormal events in multiple biosphere variables. In a first step we pre-treat the variables by removing the seasonality and normalizing them locally (μ=0,σ=1). Additionally we have regionalized the area of study into subregions of similar climate conditions, by using the Köppen climate classification. For each climate region and variable we have selected the best ARMA parameters by means of a Bayesian Criteria. Then we have obtained the residuals by comparing the fitted models with the original data. To detect the extreme residuals from the 10 variables, we have computed the Mahalanobis distance to the data's mean (Hotelling's T^2), which considers the covariance matrix of the joint

  18. Evolutionary hotspots in the Mojave Desert

    USGS Publications Warehouse

    Vandergast, Amy G.; Inman, Richard D.; Barr, Kelly R.; Nussear, Kenneth E.; Esque, Todd C.; Hathaway, Stacie A.; Wood, Dustin A.; Medica, Philip A.; Breinholt, Jesse W.; Stephen, Catherine L.; Gottscho, Andrew D.; Marks, Sharyn B.; Jennings, W. Bryan; Fisher, Robert N.

    2013-01-01

    Genetic diversity within species provides the raw material for adaptation and evolution. Just as regions of high species diversity are conservation targets, identifying regions containing high genetic diversity and divergence within and among populations may be important to protect future evolutionary potential. When multiple co-distributed species show spatial overlap in high genetic diversity and divergence, these regions can be considered evolutionary hotspots. We mapped spatial population genetic structure for 17 animal species across the Mojave Desert, USA. We analyzed these in concurrence and located 10 regions of high genetic diversity, divergence or both among species. These were mainly concentrated along the western and southern boundaries where ecotones between mountain, grassland and desert habitat are prevalent, and along the Colorado River. We evaluated the extent to which these hotspots overlapped protected lands and utility-scale renewable energy development projects of the Bureau of Land Management. While 30–40% of the total hotspot area was categorized as protected, between 3–7% overlapped with proposed renewable energy project footprints, and up to 17% overlapped with project footprints combined with transmission corridors. Overlap of evolutionary hotspots with renewable energy development mainly occurred in 6 of the 10 identified hotspots. Resulting GIS-based maps can be incorporated into ongoing landscape planning efforts and highlight specific regions where further investigation of impacts to population persistence and genetic connectivity may be warranted.

  19. Recent results about fan noise: Its generation, radiation and suppression

    NASA Technical Reports Server (NTRS)

    Feiler, C. E.

    1982-01-01

    Fan noise including its generation, radiation characteristics, and suppression by acoustic treatment is studied. In fan noise generation, results from engine and fan experiments, using inflow control measures to suppress noise sources related to inflow distortion and turbulence, are described. The suppression of sources related to inflow allows the experiments to focus on the fan or engine internal sources. Some of the experiments incorporated pressure sensors on the fan blades to sample the flow disturbances encountered by the blades. From these data some inferences can be drawn about the origins of the disturbances. Also, hot wire measurements of a fan rotor wake field are presented and related to the fan's noise signature. The radiation and the suppression of fan noise are dependent on the acoustic modes generated by the fan. Fan noise suppression and radiation is described by relating these phenomena to the mode cutoff ratio parameter. In addition to its utility in acoustic treatment design and performance prediction, cutoff ratio was useful in developing a simple description of the radiation pattern for broadband fan noise. Some of the findings using the cutoff ratio parameter are presented.

  20. Recent results about fan noise: Its generation, radiation and suppression

    NASA Astrophysics Data System (ADS)

    Feiler, C. E.

    Fan noise including its generation, radiation characteristics, and suppression by acoustic treatment is studied. In fan noise generation, results from engine and fan experiments, using inflow control measures to suppress noise sources related to inflow distortion and turbulence, are described. The suppression of sources related to inflow allows the experiments to focus on the fan or engine internal sources. Some of the experiments incorporated pressure sensors on the fan blades to sample the flow disturbances encountered by the blades. From these data some inferences can be drawn about the origins of the disturbances. Also, hot wire measurements of a fan rotor wake field are presented and related to the fan's noise signature. The radiation and the suppression of fan noise are dependent on the acoustic modes generated by the fan. Fan noise suppression and radiation is described by relating these phenomena to the mode cutoff ratio parameter. In addition to its utility in acoustic treatment design and performance prediction, cutoff ratio was useful in developing a simple description of the radiation pattern for broadband fan noise. Some of the findings using the cutoff ratio parameter are presented.

  1. Aesthetic results following partial mastectomy and radiation therapy

    SciTech Connect

    Matory, W.E. Jr.; Wertheimer, M.; Fitzgerald, T.J.; Walton, R.L.; Love, S.; Matory, W.E.

    1990-05-01

    This study was undertaken to determine the aesthetic changes inherent in partial mastectomy followed by radiation therapy in the treatment of stage I and stage II breast cancer. A retrospective analysis of breast cancer patients treated according to the National Surgical Adjuvant Breast Project Protocol B-06 was undertaken in 57 patients from 1984 to the present. The size of mastectomy varied between 2 x 1 cm and 15 x 8 cm. Objective aesthetic outcome, as determined by physical and photographic examination, was influenced primarily by surgical technique as opposed to the effects of radiation. These technical factors included orientation of resections, breast size relative to size of resection, location of tumor, and extent and orientation of axillary dissection. Regarding cosmesis, 80 percent of patients treated in this study judged their result to be excellent or good, in comparison to 50 percent excellent or good as judged by the plastic surgeon. Only 10 percent would consider mastectomy with reconstruction for contralateral disease. Asymmetry and contour abnormalities are far more common than noted in the radiation therapy literature. Patients satisfaction with lumpectomy and radiation, however, is very high. This satisfaction is not necessarily based on objective criteria defining aesthetic parameters, but is strongly influenced by retainment of the breast as an original body part.

  2. Cloud-radiative forcing and climate: results from the Earth radiation budget experiment.

    PubMed

    Ramanathan, V; Cess, R D; Harrison, E F; Minnis, P; Barkstrom, B R; Ahmad, E; Hartmann, D

    1989-01-06

    The study of climate and climate change is hindered by a lack of information on the effect of clouds on the radiation balance of the earth, referred to as the cloud-radiative forcing. Quantitative estimates of the global distributions of cloud-radiative forcing have been obtained from the spaceborne Earth Radiation Budget Experiment (ERBE) launched in 1984. For the April 1985 period, the global shortwave cloud forcing [-44.5 watts per square meter (W/m(2))] due to the enhancement of planetary albedo, exceeded in magnitude the longwave cloud forcing (31.3 W/m(2)) resulting from the greenhouse effect of clouds. Thus, clouds had a net cooling effect on the earth. This cooling effect is large over the mid-and high-latitude oceans, with values reaching -100 W/m(2). The monthly averaged longwave cloud forcing reached maximum values of 50 to 100 W/m(2) over the convectively disturbed regions of the tropics. However, this heating effect is nearly canceled by a correspondingly large negative shortwave cloud forcing, which indicates the delicately balanced state of the tropics. The size of the observed net cloud forcing is about four times as large as the expected value of radiative forcing from a doubling of CO(2). The shortwave and longwave components of cloud forcing are about ten times as large as those for a CO(2) doubling. Hence, small changes in the cloud-radiative forcing fields can play a significant role as a climate feedback mechanism. For example, during past glaciations a migration toward the equator of the field of strong, negative cloud-radiative forcing, in response to a similar migration of cooler waters, could have significantly amplified oceanic cooling and continental glaciation.

  3. A Two-Dimensional Hydrocode to Study the Deceleration Phase and Hot-Spot Formation in Inertial Confinement Fusion Implosions

    NASA Astrophysics Data System (ADS)

    Woo, K. M.; Bose, A.; Betti, R.; Delettrez, J. A.; Anderson, K. S.; Epstein, R.

    2014-10-01

    A hydrocode was developed to study the final stage of an implosion starting from the coasting phase, including hot-spot formation and thermonuclear burn. Recently, a flux-limited multigroup diffusion approximation model has been added to study the transport of radiation energy in the deceleration phase of a spherical inertial confinement fusion target. Numerical results from the multigroup model indicate a good agreement with LILAC 1-D simulations. The code is used to study effects of radiation on the hotspot formation and distortion. Results from 2-D runs are presented and the effect of radiation transport on the deceleration-phase Rayleigh-Taylor instability is discussed. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944 and the Office of Fusion Energy Sciences Number DE-FG02-04ER54786.

  4. Multimer Formation Explains Allelic Suppression of PRDM9 Recombination Hotspots

    PubMed Central

    Baker, Christopher L.; Petkova, Pavlina; Walker, Michael; Flachs, Petr; Mihola, Ondrej; Trachtulec, Zdenek; Petkov, Petko M.; Paigen, Kenneth

    2015-01-01

    Genetic recombination during meiosis functions to increase genetic diversity, promotes elimination of deleterious alleles, and helps assure proper segregation of chromatids. Mammalian recombination events are concentrated at specialized sites, termed hotspots, whose locations are determined by PRDM9, a zinc finger DNA-binding histone methyltransferase. Prdm9 is highly polymorphic with most alleles activating their own set of hotspots. In populations exhibiting high frequencies of heterozygosity, questions remain about the influences different alleles have in heterozygous individuals where the two variant forms of PRDM9 typically do not activate equivalent populations of hotspots. We now find that, in addition to activating its own hotspots, the presence of one Prdm9 allele can modify the activity of hotspots activated by the other allele. PRDM9 function is also dosage sensitive; Prdm9 +/- heterozygous null mice have reduced numbers and less active hotspots and increased numbers of aberrant germ cells. In mice carrying two Prdm9 alleles, there is allelic competition; the stronger Prdm9 allele can partially or entirely suppress chromatin modification and recombination at hotspots of the weaker allele. In cell cultures, PRDM9 protein variants form functional heteromeric complexes which can bind hotspots sequences. When a heteromeric complex binds at a hotspot of one PRDM9 variant, the other PRDM9 variant, which would otherwise not bind, can still methylate hotspot nucleosomes. We propose that in heterozygous individuals the underlying molecular mechanism of allelic suppression results from formation of PRDM9 heteromers, where the DNA binding activity of one protein variant dominantly directs recombination initiation towards its own hotspots, effectively titrating down recombination by the other protein variant. In natural populations with many heterozygous individuals, allelic competition will influence the recombination landscape. PMID:26368021

  5. Multimer Formation Explains Allelic Suppression of PRDM9 Recombination Hotspots.

    PubMed

    Baker, Christopher L; Petkova, Pavlina; Walker, Michael; Flachs, Petr; Mihola, Ondrej; Trachtulec, Zdenek; Petkov, Petko M; Paigen, Kenneth

    2015-09-01

    Genetic recombination during meiosis functions to increase genetic diversity, promotes elimination of deleterious alleles, and helps assure proper segregation of chromatids. Mammalian recombination events are concentrated at specialized sites, termed hotspots, whose locations are determined by PRDM9, a zinc finger DNA-binding histone methyltransferase. Prdm9 is highly polymorphic with most alleles activating their own set of hotspots. In populations exhibiting high frequencies of heterozygosity, questions remain about the influences different alleles have in heterozygous individuals where the two variant forms of PRDM9 typically do not activate equivalent populations of hotspots. We now find that, in addition to activating its own hotspots, the presence of one Prdm9 allele can modify the activity of hotspots activated by the other allele. PRDM9 function is also dosage sensitive; Prdm9+/- heterozygous null mice have reduced numbers and less active hotspots and increased numbers of aberrant germ cells. In mice carrying two Prdm9 alleles, there is allelic competition; the stronger Prdm9 allele can partially or entirely suppress chromatin modification and recombination at hotspots of the weaker allele. In cell cultures, PRDM9 protein variants form functional heteromeric complexes which can bind hotspots sequences. When a heteromeric complex binds at a hotspot of one PRDM9 variant, the other PRDM9 variant, which would otherwise not bind, can still methylate hotspot nucleosomes. We propose that in heterozygous individuals the underlying molecular mechanism of allelic suppression results from formation of PRDM9 heteromers, where the DNA binding activity of one protein variant dominantly directs recombination initiation towards its own hotspots, effectively titrating down recombination by the other protein variant. In natural populations with many heterozygous individuals, allelic competition will influence the recombination landscape.

  6. A Global Moving Hotspot Reference Frame: How well it fits?

    NASA Astrophysics Data System (ADS)

    Doubrovine, P. V.; Steinberger, B.; Torsvik, T. H.

    2010-12-01

    Since the early 1970s, when Jason Morgan proposed that hotspot tracks record motion of lithosphere over deep-seated mantle plumes, the concept of fixed hotspots has dominated the way we think about absolute plate reconstructions. In the last decade, with compelling evidence for southward drift of the Hawaiian hotspot from paleomagnetic studies, and for the relative motion between the Pacific and Indo-Atlantic hotspots from refined plate circuit reconstructions, the perception changed and a global moving hotspot reference frame (GMHRF) was introduced, in which numerical models of mantle convection and advection of plume conduits in the mantle flow were used to estimate hotspot motion. This reference frame showed qualitatively better performance in fitting hotspot tracks globally, but the error analysis and formal estimates of the goodness of fitted rotations were lacking in this model. Here we present a new generation of the GMHRF, in which updated plate circuit reconstructions and radiometric age data from the hotspot tracks were combined with numerical models of plume motion, and uncertainties of absolute plate rotations were estimated through spherical regression analysis. The overall quality of fit was evaluated using a formal statistical test, by comparing misfits produced by the model with uncertainties assigned to the data. Alternative plate circuit models linking the Pacific plate to the plates of Indo-Atlantic hemisphere were tested and compared to the fixed hotspot models with identical error budgets. Our results show that, with an appropriate choice of the Pacific plate circuit, it is possible to reconcile relative plate motions and modeled motions of mantle plumes globally back to Late Cretaceous time (80 Ma). In contrast, all fixed hotspot models failed to produce acceptable fits for Paleogene to Late Cretaceous time (30-80 Ma), highlighting significance of relative motion between the Pacific and Indo-Atlantic hotspots during this interval. The

  7. Prone Breast Intensity Modulated Radiation Therapy: 5-Year Results

    SciTech Connect

    Osa, Etin-Osa O.; DeWyngaert, Keith; Roses, Daniel; Speyer, James; Guth, Amber; Axelrod, Deborah; Fenton Kerimian, Maria; Goldberg, Judith D.; Formenti, Silvia C.

    2014-07-15

    Purpose: To report the 5-year results of a technique of prone breast radiation therapy delivered by a regimen of accelerated intensity modulated radiation therapy with a concurrent boost to the tumor bed. Methods and Materials: Between 2003 and 2006, 404 patients with stage I-II breast cancer were prospectively enrolled into 2 consecutive protocols, institutional trials 03-30 and 05-181, that used the same regimen of 40.5 Gy/15 fractions delivered to the index breast over 3 weeks, with a concomitant daily boost to the tumor bed of 0.5 Gy (total dose 48 Gy). All patients were treated after segmental mastectomy and had negative margins and nodal assessment. Patients were set up prone: only if lung or heart volumes were in the field was a supine setup attempted and chosen if found to better spare these organs. Results: Ninety-two percent of patients were treated prone, 8% supine. Seventy-two percent had stage I, 28% stage II invasive breast cancer. In-field lung volume ranged from 0 to 228.27 cm{sup 3}, mean 19.65 cm{sup 3}. In-field heart volume for left breast cancer patients ranged from 0 to 21.24 cm{sup 3}, mean 1.59 cm{sup 3}. There was no heart in the field for right breast cancer patients. At a median follow-up of 5 years, the 5-year cumulative incidence of isolated ipsilateral breast tumor recurrence was 0.82% (95% confidence interval [CI] 0.65%-1.04%). The 5-year cumulative incidence of regional recurrence was 0.53% (95% CI 0.41%-0.69%), and the 5-year overall cumulative death rate was 1.28% (95% CI 0.48%-3.38%). Eighty-two percent (95% CI 77%-85%) of patients judged their final cosmetic result as excellent/good. Conclusions: Prone accelerated intensity modulated radiation therapy with a concomitant boost results in excellent local control and optimal sparing of heart and lung, with good cosmesis. Radiation Therapy Oncology Group protocol 1005, a phase 3, multi-institutional, randomized trial is ongoing and is evaluating the equivalence of a similar dose and

  8. Results of Tests on Radiators for Aircraft Engines

    NASA Technical Reports Server (NTRS)

    Dickinson, H C; James, W S; Kleinschmidt, R V

    1920-01-01

    Part 1 is to present the results of tests on 56 types of core in a form convenient for use in the study of the performance of and possible improvements in existing designs. Working rules are given by which the data contained in the report may be used, and the most obvious conclusions as to the behavior of cores are summarized. Part 2 presents the results of tests made to determine the pressure necessary to produce water flows up to 50 gallons per minute through an 8-inch square section of radiator core. These data are of special value in evaluating the hydraulic head against which the circulating pump is required to operate.

  9. Prone breast intensity modulated radiation therapy: 5-year results.

    PubMed

    Osa, Etin-Osa O; DeWyngaert, Keith; Roses, Daniel; Speyer, James; Guth, Amber; Axelrod, Deborah; Fenton Kerimian, Maria; Goldberg, Judith D; Formenti, Silvia C

    2014-07-15

    To report the 5-year results of a technique of prone breast radiation therapy delivered by a regimen of accelerated intensity modulated radiation therapy with a concurrent boost to the tumor bed. Between 2003 and 2006, 404 patients with stage I-II breast cancer were prospectively enrolled into 2 consecutive protocols, institutional trials 03-30 and 05-181, that used the same regimen of 40.5 Gy/15 fractions delivered to the index breast over 3 weeks, with a concomitant daily boost to the tumor bed of 0.5 Gy (total dose 48 Gy). All patients were treated after segmental mastectomy and had negative margins and nodal assessment. Patients were set up prone: only if lung or heart volumes were in the field was a supine setup attempted and chosen if found to better spare these organs. Ninety-two percent of patients were treated prone, 8% supine. Seventy-two percent had stage I, 28% stage II invasive breast cancer. In-field lung volume ranged from 0 to 228.27 cm(3), mean 19.65 cm(3). In-field heart volume for left breast cancer patients ranged from 0 to 21.24 cm(3), mean 1.59 cm(3). There was no heart in the field for right breast cancer patients. At a median follow-up of 5 years, the 5-year cumulative incidence of isolated ipsilateral breast tumor recurrence was 0.82% (95% confidence interval [CI] 0.65%-1.04%). The 5-year cumulative incidence of regional recurrence was 0.53% (95% CI 0.41%-0.69%), and the 5-year overall cumulative death rate was 1.28% (95% CI 0.48%-3.38%). Eighty-two percent (95% CI 77%-85%) of patients judged their final cosmetic result as excellent/good. Prone accelerated intensity modulated radiation therapy with a concomitant boost results in excellent local control and optimal sparing of heart and lung, with good cosmesis. Radiation Therapy Oncology Group protocol 1005, a phase 3, multi-institutional, randomized trial is ongoing and is evaluating the equivalence of a similar dose and fractionation approach to standard 6-week radiation therapy with a

  10. Assigning a Price to Radiative Forcing: Methods, Results, and Implications

    NASA Astrophysics Data System (ADS)

    Lutz, D. A.; Howarth, R. B.

    2015-12-01

    Climate change mitigation frameworks have increasingly begun to include components that involve active management of the land surface. Predominantly, these programs focus on the sequestration of greenhouse gasses in vegetation and soils, generating offset credits for projects which demonstrate considerable storage. However, it is widely known that biogeophysical interactions between the land surface and the atmosphere, such as latent and sensible heat flux, albedo radiative forcing, and surface roughness, can in many cases outweigh the influence of greenhouse gas storage on global and local climate. Surface albedo, in particular, has attracted attention in the context of these frameworks because it has been shown to influence the overall climate benefits of high-latitude forest growth through tradeoffs between carbon sequestration and radiative forcing from seasonal snow cover albedo. Here we review a methodology for pricing albedo-related radiative forcing through the use of an integrated assessment model, present the results under several emissions and social preference scenarios, and describe the implications that this pricing methodology may have on forest land management in the Northeastern United States. Additionally, we investigate the consequences of projected decreased winter precipitation on the net climate benefits of snow albedo throughout the state of New Hampshire, USA.

  11. Wave propagation in tyres and the resultant noise radiation

    NASA Astrophysics Data System (ADS)

    Gi-Jeon, Kim

    Tyre noise has become an increasingly important road traffic noise source. This is because other sources on the vehicle, such as the air intake system, the exhaust system and the engine, have tended to become relatively quieter. This situation forces the tyre noise component to be reduced in order to achieve a reduction in the overall traffic noise level. In the research reported here, vibration, sound radiation and sound transmission of a passenger car radial tyre were investigated. The first half of this thesis discusses the vibration characteristics using two methods; (1)FEM to analysis modal behaviour in detail, (2)Analytical models to interpret the FEM results. These methods have both advantages and disadvantages in investigating tyre vibration. Combining the two methods is necessary in order to a fully understand the vibration behaviour of a tyre. Dispersion relationships and the related frequency of tyre modes is analysed by FEM and the flexural wave propagation in the tyre shell and the sound radiation of the tyre wall by flexural modes is analyzed using plate and shell theory. The second part of this thesis discusses the radiation and transmission of tyre noise. To predict the radiation of sound with only a knowledge of the surface vibration velocity, the experimental Green's functions were estimated by using the acoustic reciprocity principle. This technique was also applied to separate airborne structure borne noise for identification of the transmission path of tyre noise into a vehicle cabin and quantification of the relative contribution of various regions of the vibrating tyre surface to vehicle interior noise. The application of acoustic reciprocity for the tyre noise problem was verified and compared with BEM analysis.

  12. Hotspot Motion, Before and After the Hawaiian-Emperor Bend

    NASA Astrophysics Data System (ADS)

    Tarduno, J. A.; Bono, R. K.

    2014-12-01

    Hawaiian hotspot motion of >40 mm/yr is best documented by paleomagnetic investigations of basalt cores recovered by ocean drilling of the Emperor seamounts during ODP Leg 197 (Tarduno et al., 2003). These data indicate that the trend of the Emperor Seamounts dominantly records motion of the hotspot in the mantle, further suggesting that the great Hawaiian-Emperor bend (HEB) reflects mainly a change in hotspot motion. Data used for Pacific "absolute plate motion models" for times before the age of the HEB are also internally inconsistent with a fixed hotspot assumption; at present the best way to estimate Pacific absolute plate motion prior to the HEB bend is through use of predictions derived from plate circuits (e.g. Doubrovine and Tarduno, 2008). These analyses predict much less motion for the hotspot responsible for the Louisville Seamount chain, as has been observed by paleomagnetic analyses of cores recovered by IODP Expedition 330 (Koppers et al., 2012). Together, the ocean drilling data sets favor hotspot-specific processes to explain high drift rates, such as the model whereby the Hawaiian mantle plume was captured by a ridge in the Late Cretaceous, and subsequent changes in sub-Pacific mantle flow resulted in the trend of the Emperor Seamounts (Tarduno et al., 2009). However, the question of whether there is a smaller signal of motion between groups of hotspots remains. Plate circuit analyses yield a small discrepancy between predicted and actual hotspot locations for times between ca. 47 Ma and 10 Ma that could be a signal of continued southward migration of the Hawaiian hotspot. Alternatively, this could reflect the motion of the group of Indo-Atlantic hotspots relative to Hawaii. New paleomagnetic data from Midway Atoll (ca. 27 Ma) suggests little difference with the present-day latitude of the plume, indicating that the rate of motion of either the Hawaiian hotspot, or the Indo-Atlantic hotspot group, was about 15 mm/yr between 47 and 27 Ma. This

  13. The spatial regulation of meiotic recombination hotspots: are all DSB hotspots crossover hotspots?

    PubMed

    Serrentino, Maria-Elisabetta; Borde, Valérie

    2012-07-15

    A key step for the success of meiosis is programmed homologous recombination, during which crossovers, or exchange of chromosome arms, take place. Crossovers increase genetic diversity but their main function is to ensure accurate chromosome segregation. Defects in crossover number and position produce aneuploidies that represent the main cause of miscarriages and chromosomal abnormalities such as Down's syndrome. Recombination is initiated by the formation of programmed double strand breaks (DSBs), which occur preferentially at places called DSB hotspots. Among all DSBs generated, only a small fraction is repaired by crossover, the other being repaired by other homologous recombination pathways. Crossover maps have been generated in a number of organisms, defining crossover hotspots. With the availability of genome-wide maps of DSBs as well as the ability to measure genetically the repair outcome at several hotspots, it is becoming more and more clear that not all DSB hotspots behave the same for crossover formation, suggesting that chromosomal features distinguish different types of hotspots.

  14. Earth radiation budget - Results of outgoing longwave radiation from Nimbus-7, NOAA-9, and ERBS satellites

    NASA Technical Reports Server (NTRS)

    Bess, T. D.; Smith, G. L.

    1993-01-01

    Outgoing longwave radiation (OLR) data from Nimbus-7 ERB wide field-of-view instruments are compared with results from the ERBE instruments aboard the NOAA-9 and NOAA-10 satellites. Over most regions of the globe, the agreement between the two sets of OLR results is generally to within 8 W/sq m. There are larger differences at higher latitudes and regions concentrated over land and desert. Results of daytime and nighttime differences suggest that the shortwave channels may be at fault due to their different design for Nimbus-7 and NOAA-9. Some of the differences may also be related to different viewing geometry of the two satellites.

  15. Earth radiation budget - Results of outgoing longwave radiation from Nimbus-7, NOAA-9, and ERBS satellites

    NASA Technical Reports Server (NTRS)

    Bess, T. D.; Smith, G. L.

    1993-01-01

    Outgoing longwave radiation (OLR) data from Nimbus-7 ERB wide field-of-view instruments are compared with results from the ERBE instruments aboard the NOAA-9 and NOAA-10 satellites. Over most regions of the globe, the agreement between the two sets of OLR results is generally to within 8 W/sq m. There are larger differences at higher latitudes and regions concentrated over land and desert. Results of daytime and nighttime differences suggest that the shortwave channels may be at fault due to their different design for Nimbus-7 and NOAA-9. Some of the differences may also be related to different viewing geometry of the two satellites.

  16. Preliminary results from Radiation Environment Investigations on GIOVE-A

    NASA Astrophysics Data System (ADS)

    Underwood, C. I.; Taylor, B.; Ryden, K. A.; Rodgers, D. J.; Dyer, C. S.; Evans, H. D. R.; Daly, E. J.

    GIOVE-A is a small satellite build by SSTL UK for the European Space Agency as a first element of its Galileo satellite navigation programme GIOVE-A s primary payload is a navigation payload to secure use of the frequencies allocated by the International Telecommunications Union ITU for the Galileo system and to demonstrate critical technologies for the navigation payload of future operational Galileo satellites It also includes radiation environments and effects experiments constructed by the University of Surrey CEDEX and QinetiQ MERLIN to characterise the hazardous MEO environment GIOVE-A was launched 28 December 2005 into a 24000 km circular orbit with 56 degree inclination The environment experiments contain detectors to register the electron proton and ion signals and also to investigate the resulting total dose and charging environments The payloads will be described and preliminary results will be presented

  17. Titanium-Water Thermosyphon Gamma Radiation Exposure and Results

    NASA Technical Reports Server (NTRS)

    Sanzi, James, L.A; Jaworske, Donald, A.; Goodenow, Debra, A.

    2012-01-01

    Titanium-water thermosyphons are being considered for use in heat rejection systems for fission power systems. Their proximity to the nuclear reactor will result in some gamma irradiation. Noncondensable gas formation from radiation-induced breakdown of water over time may render portions of the thermosyphon condenser inoperable. A series of developmental thermosyphons were operated at nominal operating temperature under accelerated gamma irradiation, with exposures on the same order of magnitude as that expected in 8 years of heat rejection system operation. Temperature data were obtained during exposure at three locations on each thermosyphon: evaporator, condenser, and condenser end cap. Some noncondensable gas was evident; however, thermosyphon performance was not affected because the noncondensable gas was compressed into the fill tube region at the top of the thermosyphon, away from the heat rejecting fin. The trend appeared to be an increasing amount of noncondensable gas formation with increasing gamma irradiation dose. Hydrogen is thought to be the most likely candidate for the noncondensable gas and hydrogen is known to diffuse through grain boundaries. Post-exposure evaluation of one thermosyphon in a vacuum chamber and at temperature revealed that the noncondensable gas diffused out of the thermosyphon over a relatively short period of time. Further research shows a number of experimental and theoretical examples of radiolysis occurring through gamma radiation alone in pure water.

  18. Titanium-Water Thermosyphon Gamma Radiation Effects and Results

    NASA Technical Reports Server (NTRS)

    Sanzi, James L.; Jaworske, Donald A.; Goodenow, Debra A.

    2012-01-01

    Titanium-water thermosyphons are being considered for use in heat rejection systems for fission power systems. Their proximity to the nuclear reactor will result in some exposure to gamma irradiation. Non-condensable gas formation from radiation may breakdown water over time and render a portion of the thermosyphon condenser inoperable. A series of developmental thermosyphons were operated at nominal operating temperature with accelerated gamma irradiation exposures on the same order of magnitude that is expected in eight years of heat rejection system operation. Temperature data were obtained during exposure at three locations on each thermosyphon; evaporator, condenser, and condenser end cap. Some non-condensable gas was evident, however thermosyphon performance was not affected because the non-condensable gas was compressed into the fill tube region at the top of the thermosyphon, away from the heat rejecting fin. The trend appeared to be an increasing amount of non-condensable gas formation with increasing gamma irradiation dose. Hydrogen is thought to be the most likely candidate for the non-condensable gas and hydrogen is known to diffuse through grain boundaries. Post-exposure evaluation of selected thermosyphons at temperature and in a vacuum chamber revealed that the non-condensable gas likely diffused out of the thermosyphons over a relatively short period of time. Further research shows a number of experimental and theoretical examples of radiolysis occurring through gamma radiation alone in pure water.

  19. Recent Radiation Test Results for Trench Power MOSFETs

    NASA Technical Reports Server (NTRS)

    Lauenstein, Jean-Marie; Casey, Megan C.; Wilcox, Edward P.; Phan, Anthony M.; Kim, Hak S.; Topper, Alyson D.; Ladbury, Raymond L.; Label, Kenneth A.

    2017-01-01

    Single-event effect (SEE) radiation test results are presented for various trench-gate power MOSFETs. The heavy-ion response of the first (and only) radiation-hardened trench-gate power MOSFET is evaluated: the manufacturer SEE response curve is verified and importantly, no localized dosing effects are measured, distinguishing it from other, non-hardened trench-gate power MOSFETs. Evaluations are made of n-type commercial and both n- and p-type automotive grade trench-gate device using ions comparable to of those on the low linear energy transfer (LET) side of the iron knee of the galactic cosmic ray spectrum, to explore suitability of these parts for missions with higher risk tolerance and shorter duration, such as CubeSats. Part-to-part variability of SEE threshold suggests testing with larger sample sizes and applying more aggressive derating to avoid on-orbit failures. The n-type devices yielded expected localized dosing effects including when irradiated in an unbiased (0-V) configuration, adding to the challenge of inserting these parts into space flight missions.

  20. Effects of cloud-radiation schemes on climate model results

    SciTech Connect

    Somerville, R.C.J.; Iacobellis, S.F.; Lee, W.H.

    1996-12-31

    Using a modern atmospheric general circulation model (the National Center for Atmospheric Research Community Climate Model: CCM2), the authors have investigated the effects on climate sensitivity of several different cloud-radiation parameterizations. At the same time, they have validated these parameterizations directly with observations from field experiments. In addition to the original cloud-radiation scheme of CCM2, the authors tested four parameterizations incorporating prognostic cloud water: one version with prescribed cloud radiative properties and three other versions with interactive cloud radiative properties. They applied a diagnostic radiation calculation to investigate the partial contributions of high, middle and low cloud to the total cloud radiative forcing, as well as the contributions of water vapor, temperature and cloud to the net climate feedback.

  1. Comparative phylogeography of oceanic archipelagos: Hotspots for inferences of evolutionary process

    PubMed Central

    Shaw, Kerry L.; Gillespie, Rosemary G.

    2016-01-01

    Remote island archipelagos offer superb opportunities to study the evolution of community assembly because of their relatively young and simple communities where speciation contributes to the origin and evolution of community structure. There is great potential for common phylogeographic patterns among remote archipelagos that originate through hotspot volcanism, particularly when the islands formed are spatially isolated and linearly arranged. The progression rule is characterized by a phylogeographic concordance between island age and lineage age in a species radiation. Progression is most likely to arise when a species radiation begins on an older island before the emergence of younger islands of a hotspot archipelago. In the simplest form of progression, colonization of younger islands as they emerge and offer appropriate habitat, is coincident with cladogenesis. In this paper, we review recent discoveries of the progression rule on seven hotspot archipelagos. We then discuss advantages that progression offers to the study of community assembly, and insights that community dynamics may offer toward understanding the evolution of progression. We describe results from two compelling cases of progression where the mosaic genome may offer insights into contrasting demographic histories that shed light on mechanisms of speciation and progression on remote archipelagos. PMID:27432948

  2. The earth radiation budget experiment: Early validation results

    NASA Astrophysics Data System (ADS)

    Smith, G. Louis; Barkstrom, Bruce R.; Harrison, Edwin F.

    The Earth Radiation Budget Experiment (ERBE) consists of radiometers on a dedicated spacecraft in a 57° inclination orbit, which has a precessional period of 2 months, and on two NOAA operational meteorological spacecraft in near polar orbits. The radiometers include scanning narrow field-of-view (FOV) and nadir-looking wide and medium FOV radiometers covering the ranges 0.2 to 5 μm and 5 to 50 μm and a solar monitoring channel. This paper describes the validation procedures and preliminary results. Each of the radiometer channels underwent extensive ground calibration, and the instrument packages include in-flight calibration facilities which, to date, show negligible changes of the instruments in orbit, except for gradual degradation of the suprasil dome of the shortwave wide FOV (about 4% per year). Measurements of the solar constant by the solar monitors, wide FOV, and medium FOV radiometers of two spacecraft agree to a fraction of a percent. Intercomparisons of the wide and medium FOV radiometers with the scanning radiometers show agreement of 1 to 4%. The multiple ERBE satellites are acquiring the first global measurements of regional scale diurnal variations in the Earth's radiation budget. These diurnal variations are verified by comparison with high temporal resolution geostationary satellite data. Other principal investigators of the ERBE Science Team are: R. Cess, SUNY, Stoneybrook; J. Coakley, NCAR; C. Duncan, M. King and A Mecherikunnel, Goddard Space Flight Center, NASA; A. Gruber and A.J. Miller, NOAA; D. Hartmann, U. Washington; F.B. House, Drexel U.; F.O. Huck, Langley Research Center, NASA; G. Hunt, Imperial College, London U.; R. Kandel and A. Berroir, Laboratory of Dynamic Meteorology, Ecole Polytechique; V. Ramanathan, U. Chicago; E. Raschke, U. of Cologne; W.L. Smith, U. of Wisconsin and T.H. Vonder Haar, Colorado State U.

  3. Models for the hotspot distribution

    NASA Technical Reports Server (NTRS)

    Jurdy, Donna M.; Stefanick, Michael

    1990-01-01

    Published hotspot catalogs all show a hemispheric concentration beyond what can be expected by chance. Cumulative distributions about the center of concentration are described by a power law with a fractal dimension closer to 1 than 2. Random sets of the corresponding sizes do not show this effect. A simple shift of the random sets away from a point would produce distributions similar to those of hotspot sets. The possible relation of the hotspots to the locations of ridges and subduction zones is tested using large sets of randomly-generated points to estimate areas within given distances of the plate boundaries. The probability of finding the observed number of hotspots within 10 deg of the ridges is about what is expected.

  4. Earth Radiation Budget: Results of outgoing longwave radiation from Nimbus-7, NOAA-9, and ERBS satellites

    SciTech Connect

    Bess, T.D.; Smith, G.L. )

    1993-05-01

    Eighteen months of wide field-of-view (WFOV) outgoing longwave radiation (OLR) measurements from the Earth Radiation Budget Experiment (ERBE) NOAA-9 and NOAA-10 spacecraft have been deconvolved to produce resolution-enhanced flux maps at the top of the atmosphere. NOAA-9 had a 0230 LST equator-crossing time, and NOAA-10 a 0730 LST equator-crossing time. Intercomparison of these results with ERBE scanner and numerical filtered WFOV results is made. Results have also been compared with corresponding months of deconvolved results from the Nimbus-7 spacecraft (1200 LST equator crossing). Comparisons have been made of zonal profile plots of OLR for the different sensors and of contour maps of differences in OLR between sensors. In general Nimbus-7 OLR results show reasonable agreement with NOAA-9 and NOAA-10 over most regions of the globe. The largest differences occur over the extratropics, noticeably over land and especially over deserts. This study suggests that long-term monitoring of OLR with WFOV sensors is feasible for globally averaged trends to an accuracy of less than 1 W m[sup [minus]2], for the global absolute mean to within 3 W m[sup [minus]2], and for regional monthly means to within 8 W m[sup [minus]2] for most of the globe. Global averages for numerical filtered and deconvolved NOAA-9 WFOV results are consistently higher than Nimbus-7 deconvolved results because NOAA-9 results over land and deserts are higher. However, the ERBE NOAA-9 scanner gives smaller values of OLR over most regions of the globe than either the NOAA-9 WFOV numerical filtered or WFOV deconvolved results. 17 refs., 15 figs.

  5. COMMISSIONING AND FIRST RESULTS FROM CHANNELING RADIATION AT FAST

    SciTech Connect

    Halavanau, A.; Mihalcea, D.; Broemmelsiek, D.; Edstrom, D.; Sen, T.; Romanov, A.; Ruan, J.; Shiltsev, V.; Kobak, P.; Rush, W.; Hyun, J.

    2016-10-18

    X-rays have widespread applications in science and industry, but developing a simple, compact, and high-quality X-ray source remains a challenge. Our collaboration has explored the possible use of channeling radiation driven by a 50 MeV low-emittance electron beam to produce narrowband hard X-rays with photon energy of 40 to 140 keV [8,9,11]. Here we present the simulated X-ray spectra including the background bremsstrahlung contribution, and a description of the required optimization of the relevant electron-beam parameters necessary to maximize brilliance of the resulting X-ray beam. Results are presented from our test of this, carried out at the Fermilab Accelerator Science & Technology (FAST) facility’s 50-MeV low-energy electron injector. As a result of the beam parameters, made possible by the photo-injector based SRF linac, the average brilliance at FAST was expected to be about one order of magnitude higher than that in previous experiments.

  6. Imbalance aware lithography hotspot detection: a deep learning approach

    NASA Astrophysics Data System (ADS)

    Yang, Haoyu; Luo, Luyang; Su, Jing; Lin, Chenxi; Yu, Bei

    2017-03-01

    With the advancement of VLSI technology nodes, light diffraction caused lithographic hotspots have become a serious problem affecting manufacture yield. Lithography hotspot detection at the post-OPC stage is imperative to check potential circuit failures when transferring designed patterns onto silicon wafers. Although conventional lithography hotspot detection methods, such as machine learning, have gained satisfactory performance, with extreme scaling of transistor feature size and more and more complicated layout patterns, conventional methodologies may suffer from performance degradation. For example, manual or ad hoc feature extraction in a machine learning framework may lose important information when predicting potential errors in ultra-large-scale integrated circuit masks. In this paper, we present a deep convolutional neural network (CNN) targeting representative feature learning in lithography hotspot detection. We carefully analyze impact and effectiveness of different CNN hyper-parameters, through which a hotspot-detection-oriented neural network model is established. Because hotspot patterns are always minorities in VLSI mask design, the training data set is highly imbalanced. In this situation, a neural network is no longer reliable, because a trained model with high classification accuracy may still suffer from high false negative results (missing hotspots), which is fatal in hotspot detection problems. To address the imbalance problem, we further apply minority upsampling and random-mirror flipping before training the network. Experimental results show that our proposed neural network model achieves highly comparable or better performance on the ICCAD 2012 contest benchmark compared to state-of-the-art hotspot detectors based on deep or representative machine leaning.

  7. Preliminary results of a three-dimensional radiative transfer model

    SciTech Connect

    O`Hirok, W.

    1995-09-01

    Clouds act as the primary modulator of the Earth`s radiation at the top of the atmosphere, within the atmospheric column, and at the Earth`s surface. They interact with both shortwave and longwave radiation, but it is primarily in the case of shortwave where most of the uncertainty lies because of the difficulties in treating scattered solar radiation. To understand cloud-radiative interactions, radiative transfer models portray clouds as plane-parallel homogeneous entities to ease the computational physics. Unfortunately, clouds are far from being homogeneous, and large differences between measurement and theory point to a stronger need to understand and model cloud macrophysical properties. In an attempt to better comprehend the role of cloud morphology on the 3-dimensional radiation field, a Monte Carlo model has been developed. This model can simulate broadband shortwave radiation fluxes while incorporating all of the major atmospheric constituents. The model is used to investigate the cloud absorption anomaly where cloud absorption measurements exceed theoretical estimates and to examine the efficacy of ERBE measurements and cloud field experiments. 3 figs.

  8. Radiation Control on Uzbekistan Borders—Results and Perspectives

    NASA Astrophysics Data System (ADS)

    Petrenko, Vitaliy; Yuldashev, Bekhzod; Ismailov, Ulughbek; Shipilov, Nikolay; Chipizubov, Sergey; Avezov, Anvar

    2009-12-01

    The measures and actions on prevention, detection and response to criminal or unauthorized acts involving radioactive materials in Uzbekistan are presented. In frames of program of radiation monitoring to prevent illicit trafficking of nuclear and radioactive materials main customs border checkpoints were equipped with commercial radiation portal monitors. Special radiation monitors elaborated and manufactured in INP AS RU are installed in INP(main gates, research reactor and laboratory building) to provide nuclear security of Institute facilities. The experience of Uzbekistan in establishing radiation monitoring systems on its borders, their operation and maintenance would be useful for realization of proposed plan of strengthening measures to prevent illicit trafficking in Republics of Central Asia region.

  9. Radiation Control on Uzbekistan Borders - Results and Perspectives

    SciTech Connect

    Petrenko, Vitaliy; Yuldashev, Bekhzod; Ismailov, Ulughbek; Shipilov, Nikolay; Chipizubov, Sergey; Avezov, Anvar

    2009-12-02

    The measures and actions on prevention, detection and response to criminal or unauthorized acts involving radioactive materials in Uzbekistan are presented. In frames of program of radiation monitoring to prevent illicit trafficking of nuclear and radioactive materials main customs border checkpoints were equipped with commercial radiation portal monitors. Special radiation monitors elaborated and manufactured in INP AS RU are installed in INP(main gates, research reactor and laboratory building) to provide nuclear security of Institute facilities. The experience of Uzbekistan in establishing radiation monitoring systems on its borders, their operation and maintenance would be useful for realization of proposed plan of strengthening measures to prevent illicit trafficking in Republics of Central Asia region.

  10. Recent MARK III results in radiative J/psi decays

    SciTech Connect

    Toki, W.

    1985-11-01

    New results on the zeta(2.2) are reported. Mark III has analyzed new J/psi data and reconfirmed the zeta(2.2) in radiative J/psi decays to K/sub S//sup 0/K/sub S//sup 0/ and K/sup +/K/sup -/. The significances of the signals are 3.6 and 4.5 standard deviations, the masses, 2.232 +- .007 +- .007 and 2.230 +- .006 +- .014 GeV/c/sup 2/, and the widths, 0.018/sub -.015//sup +.023/ +- .010 and 0.026/sub -.016//sup +.020/ +- .017 GeV/c/sup 2/, for the K/sub S//sup 0/K/sub S//sup 0/ and K/sup +/K/sup -/ modes, respectively. The branching ratios are BR(J/psi ..-->.. ..gamma..zeta, zeta ..-->.. K/sub S//sup 0/K/sub S//sup 0/) = (3.2/sub -1.3//sub +1.6/ +- 0.7) x 10/sup -5/ and BR(J/psi ..-->.. ..gamma..zeta, zeta ..-->.. K/sup +/K/sup -/) = (4.2/sub -1.4//sup +1.7/ +- 0.8) x 10/sup -5/. 14 refs., 9 figs.

  11. Application of Terahertz Radiation to Soil Measurements: Initial Results

    PubMed Central

    Dworak, Volker; Augustin, Sven; Gebbers, Robin

    2011-01-01

    Developing soil sensors with the possibility of continuous online measurement is a major challenge in soil science. Terahertz (THz) electromagnetic radiation may provide the opportunity for the measurement of organic material density, water content and other soil parameters at different soil depths. Penetration depth and information content is important for a functional soil sensor. Therefore, we present initial research on the analysis of absorption coefficients of four different soil samples by means of THz transmission measurements. An optimized soil sample holder to determine absorption coefficients was used. This setup improves data acquisition because interface reflections can be neglected. Frequencies of 340 GHz to 360 GHz and 1.627 THz to 2.523 THz provided information about an existing frequency dependency. The results demonstrate the potential of this THz approach for both soil analysis and imaging of buried objects. Therefore, the THz approach allows different soil samples to be distinguished according to their different absorption properties so that relations among soil parameters may be established in future. PMID:22163737

  12. Nazca absolute plate motion and Pacific basin inter-hotspot motion

    NASA Astrophysics Data System (ADS)

    Harada, Y.; Wessel, P.; Naar, D.; Wilder, D.; Duncan, R. A.; Mahoney, J. J.; Johnson, K. T.; Pyle, D. G.; Ray, J. S.

    2003-04-01

    some dispersion owing to the various Nazca APM models used, the result shows that the position and ages of the modeled hotspot track well explain the observed geometry and ages, and there appears to be no systematic difference with time or distance from the present position. The suggested speed for inter-hotspot motion between the Easter and the Pacific hotspots would therefore be less than 10 mm per year.

  13. Fine-scale maps of recombination rates and hotspots in the mouse genome.

    PubMed

    Brunschwig, Hadassa; Levi, Liat; Ben-David, Eyal; Williams, Robert W; Yakir, Benjamin; Shifman, Sagiv

    2012-07-01

    Recombination events are not uniformly distributed and often cluster in narrow regions known as recombination hotspots. Several studies using different approaches have dramatically advanced our understanding of recombination hotspot regulation. Population genetic data have been used to map and quantify hotspots in the human genome. Genetic variation in recombination rates and hotspots usage have been explored in human pedigrees, mouse intercrosses, and by sperm typing. These studies pointed to the central role of the PRDM9 gene in hotspot modulation. In this study, we used single nucleotide polymorphisms (SNPs) from whole-genome resequencing and genotyping studies of mouse inbred strains to estimate recombination rates across the mouse genome and identified 47,068 historical hotspots--an average of over 2477 per chromosome. We show by simulation that inbred mouse strains can be used to identify positions of historical hotspots. Recombination hotspots were found to be enriched for the predicted binding sequences for different alleles of the PRDM9 protein. Recombination rates were on average lower near transcription start sites (TSS). Comparing the inferred historical recombination hotspots with the recent genome-wide mapping of double-strand breaks (DSBs) in mouse sperm revealed a significant overlap, especially toward the telomeres. Our results suggest that inbred strains can be used to characterize and study the dynamics of historical recombination hotspots. They also strengthen previous findings on mouse recombination hotspots, and specifically the impact of sequence variants in Prdm9.

  14. Fabrication of Regolith-Derived Radiation Shields: Preliminary Results

    NASA Technical Reports Server (NTRS)

    Mantovani, James G.; Sibille, Laurent; Townsend, Ivan I.; Delgado, Armando; Grossman, Kevin D.; Hatcher, George W.

    2016-01-01

    Unlike the Earth, Mars and asteroids do not have a magnetosphere to protect humans, mechanisms and electronics from damaging Galactic Cosmic Radiation (GCR) and solar particle events (SPE). This presents one of the highest risks to crew and onboard electronics during interplanetary journeys. The goal of this project is to evaluate the effectiveness of carbonaceous asteroids and other hydrogen-rich materials as potential radiation shielding materials, which ultimately could be tested during planned crewed missions to a captured asteroid fragment (ARM). This type of investigation represents an initial effort to develop radiation shield material compositions, production methods and technologies, and optimization methodology for manufacturing radiation shields in deep space for large exploration human missions or by emerging new industries seeking to stage their spacecraft for the exploitation of the resources of asteroids. Carbonaceous chondrites (C-type) are of particular interest as sources of compounds such as water ice and hydrogen-rich carbon molecules, which can provide sufficient low Z element density to provide radiation protection at adequate shield thicknesses.

  15. The Interaction of Mantle Plumes with Surface Thermal and Chemical Boundary Layers: Applications to Hotspots on Venus

    NASA Technical Reports Server (NTRS)

    Smrekar, S.; Parmentier, E.

    1994-01-01

    Describes the characteristics of possible hotspots on Venus, the approach used to simulate mantle upwelling, model results, and presents the implications for the properties of plumes and the lithosphere, hotspot evolution, and resurfacing on Venus.

  16. The Martian Radiation Environment Experiment -- Results and Status

    NASA Astrophysics Data System (ADS)

    Zeitlin, C.; Cleghorn, T. F.; Cucinotta, F. A.; Saganti, P.; Andersen, V.; Lee, K. T.; Pinsky, L. S.; Atwell, W.; Turner, R.

    2004-05-01

    Ionizing radiation in space presents a potentially serious health hazard to astronauts on long-duration missions. Missions that take humans outside the geomagnetosphere (which provides significant shielding for crews in low-Earth orbit) are of particular concern. A mission to Mars would expose a crew to a substantial radiation dose from high-energy heavy ions in the Galactic Cosmic Radiation (GCR). Though not expected to cause acute effects, such exposures might endanger the long-term health of crewmembers, leading to increased risk of late effects such as cancer and cataract. Since the biological effects of these ions are not well understood, NASA cannot yet specify career limits for deep-space missions. While ground-based research in radiobiology continues, it is necessary to characterize the radiation field on the Martian surface. This is determined by the radiation incident on the top of the Martian atmosphere, the transmission properties of the atmosphere, and the production of secondary particles (neutrons in particular) in the upper part of the surface. The Martian Radiation Environment Experiment (MARIE), aboard the 2001 Mars Odyssey spacecraft, has returned the first detailed measurements of the radiation field incident on the atmosphere. MARIE consists of a stack of silicon charged-particle detectors, designed to measure the nearly-constant flux of energetic Galactic Cosmic Rays (GCR) and intermittent Solar Particle Events (SPE). The detector is optimized for the detection of solar protons and helium in the energy range from 30 to 75 MeV/nucleon, though higher energies and heavier ions are also detected. Despite considerable uncertainties in data normalization, the measured dose agrees with model calculations, to an accuracy well within the (conservatively) estimated errors. As of this writing (Feb. 2004), MARIE is off, having sustained damage during the large Solar Particle Event of Oct. 29, 2003. Attempts to recover the instrument will resume in the

  17. Aircraft taxiing route planning based on airport hotspots

    NASA Astrophysics Data System (ADS)

    Wang, Xuan; Zuo, Qinghai

    2017-05-01

    In order to avoid airport surface hotspots, taxiing route planned for aircraft based on surface hotspots is proposed in this paper. Firstly, airport is abstracted into node-link model and aircraft taxiing avoidance mechanism is established. Then, a ground taxiing route optimization model which minimizes total taxiing time is proposed. A simulation is conducted based on a practical setting of 9 flights on runway 02L at a central-south airport. Simulation results indicate that total taxiing time is reduced by 243s after optimization and no taxiing conflict occurs. Meanwhile, the number of flight that taxi through hotspots area is reduced f, which effectively alleviates the risk level of hotspots and improves airport operation safety.

  18. Cone Penetrometer Load Cell Temperature and Radiation Testing Results

    SciTech Connect

    Follett, Jordan R.

    2013-08-28

    This report summarizes testing activities performed at the Pacific Northwest National Laboratory to verify the cone penetrometer load cell can withstand the tank conditions present in 241-AN-101 and 241-AN-106. The tests demonstrated the load cell device will operate under the elevated temperature and radiation levels expected to be encountered during tank farm deployment of the device.

  19. Radiation Effects on Nematodes: Results from IML-1 Esperiments

    NASA Technical Reports Server (NTRS)

    Nelson, G. A.; Schubert, W. W.; Kazarians, G. A.; Righards, G. F.; Benton, E. V; Benton, E. R.; Henke, R.

    1993-01-01

    The nematode Caenorhabditis elegans was exposed to natural space radiation using the ESA Biorack facility aboard Spacelab on International Microgravity Laboratory 1, STS-42. For the major experimental objective dormant animals were suspended in buffer or on agar or immobilized next to CR-39 plactic nuclear track detectors to correlate fluence of HZE particles with genetic events.

  20. ATM modulates the loading of recombination proteins onto a chromosomal translocation breakpoint hotspot.

    PubMed

    Sun, Jiying; Oma, Yukako; Harata, Masahiko; Kono, Kazuteru; Shima, Hiroki; Kinomura, Aiko; Ikura, Tsuyoshi; Suzuki, Hidekazu; Mizutani, Shuki; Kanaar, Roland; Tashiro, Satoshi

    2010-10-27

    Chromosome translocations induced by DNA damaging agents, such as ionizing radiation and certain chemotherapies, alter genetic information resulting in malignant transformation. Abrogation or loss of the ataxia-telangiectasia mutated (ATM) protein, a DNA damage signaling regulator, increases the incidence of chromosome translocations. However, how ATM protects cells from chromosome translocations is still unclear. Chromosome translocations involving the MLL gene on 11q23 are the most frequent chromosome abnormalities in secondary leukemias associated with chemotherapy employing etoposide, a topoisomerase II poison. Here we show that ATM deficiency results in the excessive binding of the DNA recombination protein RAD51 at the translocation breakpoint hotspot of 11q23 chromosome translocation after etoposide exposure. Binding of Replication protein A (RPA) and the chromatin remodeler INO80, which facilitate RAD51 loading on damaged DNA, to the hotspot were also increased by ATM deficiency. Thus, in addition to activating DNA damage signaling, ATM may avert chromosome translocations by preventing excessive loading of recombinational repair proteins onto translocation breakpoint hotspots.

  1. Fish-derived nutrient hotspots shape coral reef benthic communities.

    PubMed

    Shantz, Andrew A; Ladd, Mark C; Schrack, Elizabeth; Burkepile, Deron E

    2015-12-01

    Animal-derived nutrients play an important role in structuring nutrient regimes within and between ecosystems. When animals undergo repetitive, aggregating behavior through time, they can create nutrient hotspots where rates of biogeochemical activity are higher than those found in the surrounding environment. In turn, these hotspots can influence ecosystem processes and community structure. We examined the potential for reef fishes from the family Haemulidae (grunts) to create nutrient hotspots and the potential impact of these hotspots on reef communities. To do so, we tracked the schooling locations of diurnally migrating grunts, which shelter at reef sites during the day but forage off reef each night, and measured the impact of these fish schools on benthic communities. We found that grunt schools showed a high degree of site fidelity, repeatedly returning to the same coral heads. These aggregations created nutrient hotspots around coral heads where nitrogen and phosphorus delivery was roughly 10 and 7 times the respective rates of delivery to structurally similar sites that lacked schools of these fishes. In turn, grazing rates of herbivorous fishes at grunt-derived hotspots were approximately 3 times those of sites where grunts were rare. These differences in nutrient delivery and grazing led to distinct benthic communities with higher cover of crustose coralline algae and less total algal abundance at grunt aggregation sites. Importantly, coral growth was roughly 1.5 times greater at grunt hotspots, likely due to the important nutrient subsidy. Our results suggest that schooling reef fish and their nutrient subsidies play an important role in mediating community structure on coral reefs and that overfishing may have important negative consequences on ecosystem functions. As such, management strategies must consider mesopredatory fishes in addition to current protection often offered to herbivores and top-tier predators. Furthermore, our results suggest that

  2. Stable recombination hotspots in birds.

    PubMed

    Singhal, Sonal; Leffler, Ellen M; Sannareddy, Keerthi; Turner, Isaac; Venn, Oliver; Hooper, Daniel M; Strand, Alva I; Li, Qiye; Raney, Brian; Balakrishnan, Christopher N; Griffith, Simon C; McVean, Gil; Przeworski, Molly

    2015-11-20

    The DNA-binding protein PRDM9 has a critical role in specifying meiotic recombination hotspots in mice and apes, but it appears to be absent from other vertebrate species, including birds. To study the evolution and determinants of recombination in species lacking the gene that encodes PRDM9, we inferred fine-scale genetic maps from population resequencing data for two bird species: the zebra finch, Taeniopygia guttata, and the long-tailed finch, Poephila acuticauda. We found that both species have recombination hotspots, which are enriched near functional genomic elements. Unlike in mice and apes, most hotspots are shared between the two species, and their conservation seems to extend over tens of millions of years. These observations suggest that in the absence of PRDM9, recombination targets functional features that both enable access to the genome and constrain its evolution.

  3. Hot-spot qualification testing of concentrator modules

    NASA Technical Reports Server (NTRS)

    Gonzalez, C. C.; Sugimura, R. S.; Ross, R. G., Jr.

    1987-01-01

    Results of a study to determine the hot-spot susceptibility of concentrator cells, to provide a hot-spot qualification test for concentrator modules, and to provide guidelines for reducing hot-spot susceptibility are presented. Hot-spot heating occurs in a photovoltaic module when the short-circuit current of a cell is lower than the string operating current, forcing the cell into reverse bias with a concurrent power dissipation. Although the basis for the concentrator-module hot-spot qualification test is the test developed for flat-plate modules, issues such as providing cell illumination introduce additional complexities into the testing procedure. The results indicate that the same general guidelines apply to protecting concentrator modules from hot-spot stressing as apply to flat-plate modules, and recommendations are made on the number of bypass diodes required per given number of series cells per module or source circuit. A method for determining the cell temperature in the laboratory or in the field is discussed.

  4. Results from the Martian Radiation Environment Experiment MARIE

    NASA Technical Reports Server (NTRS)

    Zeitlin, C.; Cleghorn, T.; Cucinotta, F.; Saganti, P.; Andersen, V.; Lee, K.; Pinsky, L.; Atwell, W.; Turner, R.

    2003-01-01

    One of the three science instruments aboard the 2001 Mars Odyssey spacecraft is the Martian Radiation Environment Experiment, MARIE. MARIE consists of a stack of silicon detectors, augmented by a Cerenkov detector. MARIE is designed to measure a portion of the particle spectrum of the Galactic Cosmic Rays (GCR), as well as the high fluxes of low-energy protons (energies less than about 100 MeV) that are intermittently produced by active regions on the sun in Solar Particle Events (SPE). MARIE is providing the first detailed information about the radiation environment near Mars.measurements. MARIE has been operating successfully for nearly a year. Solar particle events of considerable interest have been observed, and data have been obtained that will yield GCR spectra from a novel observation point in the solar system.

  5. Results from the Earth Radiation Budget Experiment (ERBE)

    NASA Technical Reports Server (NTRS)

    Barkstrom, Bruce R.; Harrison, Edwin F.; Smith, G. Louis; Cess, Robert D.

    1989-01-01

    The Earth Radiation Budget Experiment (ERBE) has been observing the earth during the past 4 years from three satellites. Numerous validation procedures have been applied to the data. Particularly important have been intercomparisons between three channels of scanning radiometers and wide and medium field-of-view radiometers. These intercomparisons and onboard calibration targets have provided assurance of high data quality. In addition to the classic radiation budget parameters: global absorbed and emitted energy, ERBE is producing fluxes on scales of 250 km that can significantly increase understanding of the earth's climate. Of particular interest are ERBE measurements of clear-sky albedos and longwave fluxes, which are part of the ERBE data products. Use of data from the precessing ERBE satellite together with data from the sun-synchronous NOAA-9 and NOAA-10 satellites also provides information on the diurnal cycle of shortwave and longwave fluxes.

  6. Intraoperative radiation therapy in malignant glioma: early clinical results.

    PubMed

    Ortiz de Urbina, D; Santos, M; Garcia-Berrocal, I; Bustos, J C; Samblas, J; Gutierrez-Diaz, J A; Delgado, J M; Donckaster, G; Calvo, F A

    1995-08-01

    Intraoperative radiation therapy (IORT) with high energy electron beams is a treatment modality that has been included in multimodal programs in oncology to improve local tumor control. From August 1991 to December 1993, 17 patients with primary (8) or recurrent (9) high grade malignant gliomas, anaplastic astrocytoma (4), anaplastic oligodendroglioma (6) and glioblastoma multiforme (7), underwent surgical resection and a single dose of 10-20 Gy intraoperative radiation therapy was delivered in tumor bed. Fourteen patients received either pre-operative (8) or post-operative (6) external beam radiation therapy. Primary gliomas: 18-months actuarial survival rate has been 56% (range: 1-21+ months) and the median survival time has not yet been achieved. Four patients developed tumor progression (median time to tumor progression: 9 months). Recurrent gliomas: 18-months actuarial survival rate and median survival time has been 47% and 13 months (range: 6-32+ months) respectively. The median time to tumor progression was 11 months. No IORT related mortality has been observed. IORT is an attractive, tolerable and feasible treatment modality as antitumoral intensification procedure in high grade malignant gliomas.

  7. Electron Energy Distribution in Hotspots of Cygnus A:Filling the Gap with Spitzer Space Telescope

    SciTech Connect

    Stawarz, L.; Cheung, C.C.; Harris, D.E.; Ostrowski, M.

    2007-03-06

    Here we present Spitzer Space Telescope imaging of Cyg A with the Infrared Array Camera at 4.5 {micro}m and 8.0 {micro}m, resulting in the detection of the high-energy tails or cut-offs in the synchrotron spectra for all four hotspots of this archetype radio galaxy. When combined with the other data collected (and re-analyzed) from the literature, our observations allow for detailed modeling of the broad-band (radio-to-X-ray) emission for the brightest spots A and D. We confirm that the X-ray flux detected previously from these features is consistent with the synchrotron self-Compton radiation for the magnetic field intensity B {approx} 170 {micro}G in spot A, and B {approx} 270 {micro}G in spot D. We also find that the energy density of the emitting electrons is most likely larger by a factor of a few than the energy density of the hotspots magnetic field. We construct energy spectra of the radiating ultrarelativistic electrons. We find that for both hotspots A and D these spectra are consistent with a broken power-law extending from at least 100MeV up to {approx} 100GeV, and that the spectral break corresponds almost exactly to the proton rest energy of {approx} 1GeV. We argue that the shape of the electron continuum most likely reflects two different regimes of the electron acceleration process taking place at mildly relativistic shocks, rather than resulting from radiative cooling and/or absorption e.ects. In this picture the protons inertia defines the critical energy for the hotspot electrons above which Fermi-type acceleration processes may play a major role, but below which the operating acceleration mechanism has to be of a different type. At energies {approx}> 100 GeV, the electron spectra cut-off/steepen again, most likely as a result of spectral aging due to radiative loss effects. We discuss several implications of the presented analysis for the physics of extragalactic jets.

  8. Towards biodiversity hotspots effective for conserving mammals with small geographic ranges

    NASA Astrophysics Data System (ADS)

    Carrara, Rodolfo; San Blas, Germán; Agrain, Federico; Roig-Juñent, Sergio

    2017-01-01

    The main goal of using global biodiversity hotspots for conservation purposes is to protect taxa with small geographic ranges because these are highly vulnerable to extinction. However, the extent to what different hotspots types are effective for meeting this goal remains controversial because hotspots have been previously defined as either the richest or most threatened and richest sites in terms of total, endemic or threatened species. In this regard, the use of species richness to set conservation priorities is widely discussed because strategies focused on this diversity measure tend to miss many of the taxa with small geographic ranges. Here we use data on global terrestrial mammal distributions to show that, hotspots of total species, endemism and threat defined in terms of species richness are effective in including 27%, 29% and 11% respectively, of the taxa with small geographic ranges. Whilst, the same hotspot types defined in terms of a simple diversity index, which is a function of species richness and range-size rarity, include 68%, 44% and 90% respectively, of these taxa. In addition, we demonstrate that index hotspot types are highly efficient because they conserve 79% of mammal species (21% more species than richness hotspot types), with 59% of species shared by three hotspot types (31% more than richness hotspot types). These results suggest that selection of different diversity measures to define hotspots may strongly affect the achievement of conservation goals.

  9. Expected Results From Channeling Radiation Experiments at Fast

    SciTech Connect

    Sen, Tanaji; Broemmelsiek, Daniel; Edstrom, Dean; Hyun, Jibong; Mihalcea, Daniel; Piot, Philippe; Rush, Wade

    2016-06-01

    The photoinjector at the new Fermilab FAST facility will accelerate electron beams to about 50 GeV. After initial beam commissioning, channeling radiation experiments to generate hard X-rays will be performed. In the initial stage, low bunch charge beams will be used to keep the photon count rate low and avoid pile up in the detector. We report here on the optics solutions, the expected channaling spectrum including background from bremmstrahlung and the use of a Compton scatterer for higher bunch charge operation.

  10. Socioeconomic Context and the Food Landscape in Texas: Results from Hotspot Analysis and Border/Non-Border Comparison of Unhealthy Food Environments

    PubMed Central

    Salinas, Jennifer J.; Abdelbary, Bassent; Klaas, Kelly; Tapia, Beatriz; Sexton, Ken

    2014-01-01

    Purpose: The purpose of this paper is to describe the food landscape of Texas using the CDC’s Modified Retail Food Environment (mRFEI) and to make comparisons by border/non-border. Methods: The Modified Retail Food Environment index (mRFEI (2008)) is an index developed by the CDC that measures what percent of the total food vendors in a census track sell healthy food. The range of values is 0 (unhealthy areas with limited access to fruits and vegetables) to (100—Healthy). These data were linked to 2010 US Census socioeconomic and ethnic concentration data. Spatial analysis and GIS techniques were applied to assess the differences between border and non-border regions. Variables of interest were mRFEI score, median income, total population, percent total population less than five years, median age, % receiving food stamps, % Hispanic, and % with a bachelor degree. Results: Findings from this study reveal that food environment in Texas tends to be characteristic of a “food desert”. Analysis also demonstrates differences by border/non-border location and percent of the population that is foreign born and by percent of families who receive food stamps. Conclusions: Identifying the relationship between socioeconomic disparity, ethnic concentration and mRFEI score could be a fundamental step in improving health in disadvantage communities, particularly those on the Texas-Mexico border. PMID:24865399

  11. Summary of current radiation dosimetry results on manned spacecraft.

    PubMed

    Benton, E V

    1984-01-01

    Measurements of radiation exposures aboard manned space flights of various altitudes, orbital inclinations and durations were performed by means of passive radiation detectors, thermoluminescent detectors (TLD's), and in some cases by active electronic counters. The TLD's and electronic counters covered the lower portion of the LET (linear energy transfer) spectra, while the nuclear track detectors measured high-LET produced by HZE particles. In Spacelab (SL-1), TLD's recorded a range of 102 to 190-millirad, yielding an average low-LET dose rate of 11.2 mrad per day inside the module, about twice the dose rate measured on previous space shuttle flights. Because of a higher inclination of the SL-1 orbit (57 degrees versus 28.5 degrees for previous shuttle flights), substantial fluxes of highly ionizing HZE particles were also observed, yielding an overall average mission dose-equivalent of about 135 millirem, about three times higher than measured an previous shuttle missions. A dose rate more than an order of magnitude higher than for any other space shuttle light was obtained for mission STS-41C, reflecting the highest orbital altitude to date of 519 km.

  12. Radiation effects in nematodes: Results from IML-1 experiments

    NASA Technical Reports Server (NTRS)

    Nelson, G. A.; Schubert, W. W.; Kazarians, G. A.; Richards, G. F.; Benton, E. V.; Benton, E. R.; Henke, R.

    1994-01-01

    The nematode Caenorhabditis elegans was exposed to natural space radiation using the ESA biorack facility aboard Spacelab on International Microgravity Laboratory 1, STS-42. For the major experimental objective dormant animals were suspended in buffer or on agar or immobilized next to CR-39 plastic nuclear track detectors to correlate fluence of HZE particles with genetic events. This configuration was used to isolate mutations in a set of 350 essential genes as well as in the unc-22 structural gene. From flight samples 13 mutants in the unc-22 gene were isolated along with 53 lethal mutations from autosomal regions balanced by a translocation eT1(III;V). Preliminary analysis suggests that mutants from worms correlated with specific cosmic ray tracks may have a higher proportion of rearrangements than those isolated from tube cultures on a randomly sampled basis. Flight sample mutation rate was approximately 8-fold higher than ground controls which exhibited laboratory spontaneous frequencies.

  13. Radiation effects in nematodes: results from IML-1 experiments.

    PubMed

    Nelson, G A; Schubert, W W; Kazarians, G A; Richards, G F; Benton, E V; Benton, E R; Henke, R

    1994-10-01

    The nematode Caenorhabditis elegans was exposed to natural space radiation using the ESA Biorack facility aboard Spacelab on International Microgravity Laboratory 1, STS-42. For the major experimental objective dormant animals were suspended in buffer or on agar or immobilized next to CR-39 plastic nuclear track detectors to correlate fluence of HZE particles with genetic events. This configuration was used to isolate mutations in a set of 350 essential genes as well as in the unc-22 structural gene. From flight samples 13 mutants in the unc-22 gene were isolated along with 53 lethal mutations from autosomal regions balanced by a translocation eT1(III;V). Preliminary analysis suggests that mutants from worms correlated with specific cosmic ray tracks may have a higher proportion of rearrangements than those isolated from tube cultures on a randomly sampled basis. Right sample mutation rate was approximately 8-fold higher than ground controls which exhibited laboratory spontaneous frequencies.

  14. Radiation effects in nematodes: Results from IML-1 experiments

    NASA Technical Reports Server (NTRS)

    Nelson, G. A.; Schubert, W. W.; Kazarians, G. A.; Richards, G. F.; Benton, E. V.; Benton, E. R.; Henke, R.

    1994-01-01

    The nematode Caenorhabditis elegans was exposed to natural space radiation using the ESA biorack facility aboard Spacelab on International Microgravity Laboratory 1, STS-42. For the major experimental objective dormant animals were suspended in buffer or on agar or immobilized next to CR-39 plastic nuclear track detectors to correlate fluence of HZE particles with genetic events. This configuration was used to isolate mutations in a set of 350 essential genes as well as in the unc-22 structural gene. From flight samples 13 mutants in the unc-22 gene were isolated along with 53 lethal mutations from autosomal regions balanced by a translocation eT1(III;V). Preliminary analysis suggests that mutants from worms correlated with specific cosmic ray tracks may have a higher proportion of rearrangements than those isolated from tube cultures on a randomly sampled basis. Flight sample mutation rate was approximately 8-fold higher than ground controls which exhibited laboratory spontaneous frequencies.

  15. The potential of shifting recombination hotspots to increase genetic gain in livestock breeding.

    PubMed

    Gonen, Serap; Battagin, Mara; Johnston, Susan E; Gorjanc, Gregor; Hickey, John M

    2017-07-04

    This study uses simulation to explore and quantify the potential effect of shifting recombination hotspots on genetic gain in livestock breeding programs. We simulated three scenarios that differed in the locations of quantitative trait nucleotides (QTN) and recombination hotspots in the genome. In scenario 1, QTN were randomly distributed along the chromosomes and recombination was restricted to occur within specific genomic regions (i.e. recombination hotspots). In the other two scenarios, both QTN and recombination hotspots were located in specific regions, but differed in whether the QTN occurred outside of (scenario 2) or inside (scenario 3) recombination hotspots. We split each chromosome into 250, 500 or 1000 regions per chromosome of which 10% were recombination hotspots and/or contained QTN. The breeding program was run for 21 generations of selection, after which recombination hotspot regions were kept the same or were shifted to adjacent regions for a further 80 generations of selection. We evaluated the effect of shifting recombination hotspots on genetic gain, genetic variance and genic variance. Our results show that shifting recombination hotspots reduced the decline of genetic and genic variance by releasing standing allelic variation in the form of new allele combinations. This in turn resulted in larger increases in genetic gain. However, the benefit of shifting recombination hotspots for increased genetic gain was only observed when QTN were initially outside recombination hotspots. If QTN were initially inside recombination hotspots then shifting them decreased genetic gain. Shifting recombination hotspots to regions of the genome where recombination had not occurred for 21 generations of selection (i.e. recombination deserts) released more of the standing allelic variation available in each generation and thus increased genetic gain. However, whether and how much increase in genetic gain was achieved by shifting recombination hotspots depended

  16. Thailand radiation monitoring program: a preliminary result analysis of the country's background radiation.

    PubMed

    Krisanangkura, Piyawan; Udomsomporn, Suchin

    2014-08-01

    Environmental monitoring in the context of nuclear-related activities refers to the measurements of ambient gamma dose rates in the environment and radioactivity in air, water, soil etc. Since nuclear power programme in Thailand has not yet been in place, the environment surveillance programme in Thailand currently focuses on establishing 'baseline' environmental radiation levels and radioactivity for the purpose of establishing impacts of future possible sources such as nuclear accidents. The objective is to assure assessments concerning radiation safety for the environment and public. At present, Thailand's monitoring programme operates eight fixed monitoring stations installed in various regions of Thailand; four of which have been in operation since late 2010. The ambient gamma dose rate data are routinely collected from those four real-time monitoring stations starting from October 2010 to September 2011 as described in this study. Also, the radiation data from each station are statically analysed. This study found that the dose rate from the stations located in north and north-east of Thailand showed an apparent tendency towards a diurnal pattern. With these routine data, the average exposure dose rate was possible to estimate in Thailand. Additionally, the assessment of the equivalent dose from natural background radiation was estimated.

  17. Mometasone Furoate Cream Reduces Acute Radiation Dermatitis in Patients Receiving Breast Radiation Therapy: Results of a Randomized Trial

    SciTech Connect

    Hindley, Andrew; Zain, Zakiyah; Wood, Lisa; Whitehead, Anne; Sanneh, Alison; Barber, David; Hornsby, Ruth

    2014-11-15

    Purpose: We wanted to confirm the benefit of mometasone furoate (MF) in preventing acute radiation reactions, as shown in a previous study (Boström et al, Radiother Oncol 2001;59:257-265). Methods and Materials: The study was a double-blind comparison of MF with D (Diprobase), administered daily from the start of radiation therapy for 5 weeks in patients receiving breast radiation therapy, 40 Gy in 2.67-Gy fractions daily over 3 weeks. The primary endpoint was mean modified Radiation Therapy Oncology Group (RTOG) score. Results: Mean RTOG scores were significantly less for MF than for D (P=.046). Maximum RTOG and mean erythema scores were significantly less for MF than for D (P=.018 and P=.012, respectively). The Dermatology Life Quality Index (DLQI) score was significantly less for MF than for D at weeks 4 and 5 when corrected for Hospital Anxiety and Depression (HAD) questionnaire scores. Conclusions: MF cream significantly reduces radiation dermatitis when applied to the breast during and after radiation therapy. For the first time, we have shown a significantly beneficial effect on quality of life using a validated instrument (DLQI), for a topical steroid cream. We believe that application of this cream should be the standard of care where radiation dermatitis is expected.

  18. Fixed Hot-spots Gone With Wind? Clues From Paleomagnetic Investigations of Large Igneous Provinces

    NASA Astrophysics Data System (ADS)

    Zhao, X.; Ernesto, M.

    2013-05-01

    Paleomagnetic studies of Ocean Drilling Program (ODP) 197 on samples from the Emperor-Hawaiian seamount chain suggested that these rocks formed much farther north than the hotspot currently beneath Hawaii. These findings indicate that the hotspot, once thought to be fixed beneath the Earth's crust, actually jumped southward rapidly. Here we report paleomagnetic evidence that is consistence with these findings and suggests that rapid hotspots motion (also southward jumps) occurred while the massive Ontong Java (OJP), Kerguelen Plateau (KP), and Parana Magmatic Province (PMP) large igneous provinces formed. The paleomagnetic paleolatitude for the OJP is ~20 farther north than those predicted by the Louisville hotspot model. The difference between the paleomagnetic and hotspot calculated paleolatitudes cannot be explained by true polar wander estimates derived from other lithospheric plates. Our results are therefore consistent with and extend the Emperor-Hawaiian hotspot features in the northern Pacific Ocean that suggest Late Cretaceous to Eocene motion of Pacific hotspots. Compared to the latitude of the Kerguelen hotspot, the paleolatitudes of the central and northern Kerguelen Plateau obtained by ODP Leg 183 are further north. This difference also indicates a southward movement of the Kerguelen hotspot since the Cretaceous relative to the spin axis of the Earth. Numerical modeling of plume conduit motion in a large-scale mantle flow also predicts southward motion of the Kerguelen hotspot, which is consistent with paleomagnetic results. Likewise, paleomagnetic results from PMP reveal significant southward movement of the Tristan da Cunha hotspot in the Cretaceous. Elucidating how large igneous province formation and mantle dynamics are related and whether hotspots moved at comparable rates during other times are challenges for future research.

  19. Accounting for false negatives in hotspot detection

    SciTech Connect

    Sego, Landon H.; Wilson, John E.

    2007-08-28

    Hotspot sampling designs are used in environmental sampling to identify the location of one (or more) contiguous regions of elevated contamination. These regions are known as hotspots. The problem of how to calculate the probability of detecting an elliptical hotspot using a rectangular or triangular grid of sampling points was addressed by Singer and Wickman in 1969. This approach presumed that any sample which coincided with a hotspot would detect the hotspot without error. However, for many sampling methodologies, there is a chance that the hotspot will not be detected even though it has been sampled directly--a false negative. We present a mathematical solution and a numerical algorithm which account for false negatives when calculating the probability of detecting hotspots that are circular in shape.

  20. Nanoscale hotspots due to nonequilibrium thermal transport.

    SciTech Connect

    Sinha, Sanjiv; Goodson, Kenneth E.

    2004-01-01

    Recent experimental and modeling efforts have been directed towards the issue of temperature localization and hotspot formation in the vicinity of nanoscale heat generating devices. The nonequilibrium transport conditions which develop around these nanoscale devices results in elevated temperatures near the heat source which can not be predicted by continuum diffusion theory. Efforts to determine the severity of this temperature localization phenomena in silicon devices near and above room temperature are of technological importance to the development of microelectronics and other nanotechnologies. In this work, we have developed a new modeling tool in order to explore the magnitude of the additional thermal resistance which forms around nanoscale hotspots from temperatures of 100-1000K. The models are based on a two fluid approximation in which thermal energy is transferred between ''stationary'' optical phonons and fast propagating acoustic phonon modes. The results of the model have shown excellent agreement with experimental results of localized hotspots in silicon at lower temperatures. The model predicts that the effect of added thermal resistance due to the nonequilibrium phonon distribution is greatest at lower temperatures, but is maintained out to temperatures of 1000K. The resistance predicted by the numerical code can be easily integrated with continuum models in order to predict the temperature distribution around nanoscale heat sources with improved accuracy. Additional research efforts also focused on the measurements of the thermal resistance of silicon thin films at higher temperatures, with a focus on polycrystalline silicon. This work was intended to provide much needed experimental data on the thermal transport properties for micro and nanoscale devices built with this material. Initial experiments have shown that the exposure of polycrystalline silicon to high temperatures may induce recrystallization and radically increase the thermal

  1. Impact of metric and sample size on determining malaria hotspot boundaries.

    PubMed

    Stresman, Gillian H; Giorgi, Emanuele; Baidjoe, Amrish; Knight, Phil; Odongo, Wycliffe; Owaga, Chrispin; Shagari, Shehu; Makori, Euniah; Stevenson, Jennifer; Drakeley, Chris; Cox, Jonathan; Bousema, Teun; Diggle, Peter J

    2017-04-12

    The spatial heterogeneity of malaria suggests that interventions may be targeted for maximum impact. It is unclear to what extent different metrics lead to consistent delineation of hotspot boundaries. Using data from a large community-based malaria survey in the western Kenyan highlands, we assessed the agreement between a model-based geostatistical (MBG) approach to detect hotspots using Plasmodium falciparum parasite prevalence and serological evidence for exposure. Malaria transmission was widespread and highly heterogeneous with one third of the total population living in hotspots regardless of metric tested. Moderate agreement (Kappa = 0.424) was observed between hotspots defined based on parasite prevalence by polymerase chain reaction (PCR)- and the prevalence of antibodies to two P. falciparum antigens (MSP-1, AMA-1). While numerous biologically plausible hotspots were identified, their detection strongly relied on the proportion of the population sampled. When only 3% of the population was sampled, no PCR derived hotspots were reliably detected and at least 21% of the population was needed for reliable results. Similar results were observed for hotspots of seroprevalence. Hotspot boundaries are driven by the malaria diagnostic and sample size used to inform the model. These findings warn against the simplistic use of spatial analysis on available data to target malaria interventions in areas where hotspot boundaries are uncertain.

  2. Testing the Efficacy of Global Biodiversity Hotspots for Insect Conservation: The Case of South African Katydids.

    PubMed

    Bazelet, Corinna S; Thompson, Aileen C; Naskrecki, Piotr

    2016-01-01

    The use of endemism and vascular plants only for biodiversity hotspot delineation has long been contested. Few studies have focused on the efficacy of global biodiversity hotspots for the conservation of insects, an important, abundant, and often ignored component of biodiversity. We aimed to test five alternative diversity measures for hotspot delineation and examine the efficacy of biodiversity hotspots for conserving a non-typical target organism, South African katydids. Using a 1° fishnet grid, we delineated katydid hotspots in two ways: (1) count-based: grid cells in the top 10% of total, endemic, threatened and/or sensitive species richness; vs. (2) score-based: grid cells with a mean value in the top 10% on a scoring system which scored each species on the basis of its IUCN Red List threat status, distribution, mobility and trophic level. We then compared katydid hotspots with each other and with recognized biodiversity hotspots. Grid cells within biodiversity hotspots had significantly higher count-based and score-based diversity than non-hotspot grid cells. There was a significant association between the three types of hotspots. Of the count-based measures, endemic species richness was the best surrogate for the others. However, the score-based measure out-performed all count-based diversity measures. Species richness was the least successful surrogate of all. The strong performance of the score-based method for hotspot prediction emphasizes the importance of including species' natural history information for conservation decision-making, and is easily adaptable to other organisms. Furthermore, these results add empirical support for the efficacy of biodiversity hotspots in conserving non-target organisms.

  3. Sampling effects on the identification of roadkill hotspots: Implications for survey design.

    PubMed

    Santos, Sara M; Marques, J Tiago; Lourenço, André; Medinas, Denis; Barbosa, A Márcia; Beja, Pedro; Mira, António

    2015-10-01

    Although locating wildlife roadkill hotspots is essential to mitigate road impacts, the influence of study design on hotspot identification remains uncertain. We evaluated how sampling frequency affects the accuracy of hotspot identification, using a dataset of vertebrate roadkills (n = 4427) recorded over a year of daily surveys along 37 km of roads. "True" hotspots were identified using this baseline dataset, as the 500-m segments where the number of road-killed vertebrates exceeded the upper 95% confidence limit of the mean, assuming a Poisson distribution of road-kills per segment. "Estimated" hotspots were identified likewise, using datasets representing progressively lower sampling frequencies, which were produced by extracting data from the baseline dataset at appropriate time intervals (1-30 days). Overall, 24.3% of segments were "true" hotspots, concentrating 40.4% of roadkills. For different groups, "true" hotspots accounted from 6.8% (bats) to 29.7% (small birds) of road segments, concentrating from <40% (frogs and toads, snakes) to >60% (lizards, lagomorphs, carnivores) of roadkills. Spatial congruence between "true" and "estimated" hotspots declined rapidly with increasing time interval between surveys, due primarily to increasing false negatives (i.e., missing "true" hotspots). There were also false positives (i.e., wrong "estimated" hotspots), particularly at low sampling frequencies. Spatial accuracy decay with increasing time interval between surveys was higher for smaller-bodied (amphibians, reptiles, small birds, small mammals) than for larger-bodied species (birds of prey, hedgehogs, lagomorphs, carnivores). Results suggest that widely used surveys at weekly or longer intervals may produce poor estimates of roadkill hotspots, particularly for small-bodied species. Surveying daily or at two-day intervals may be required to achieve high accuracy in hotspot identification for multiple species. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Testing the Efficacy of Global Biodiversity Hotspots for Insect Conservation: The Case of South African Katydids

    PubMed Central

    Bazelet, Corinna S.; Thompson, Aileen C.; Naskrecki, Piotr

    2016-01-01

    The use of endemism and vascular plants only for biodiversity hotspot delineation has long been contested. Few studies have focused on the efficacy of global biodiversity hotspots for the conservation of insects, an important, abundant, and often ignored component of biodiversity. We aimed to test five alternative diversity measures for hotspot delineation and examine the efficacy of biodiversity hotspots for conserving a non-typical target organism, South African katydids. Using a 1° fishnet grid, we delineated katydid hotspots in two ways: (1) count-based: grid cells in the top 10% of total, endemic, threatened and/or sensitive species richness; vs. (2) score-based: grid cells with a mean value in the top 10% on a scoring system which scored each species on the basis of its IUCN Red List threat status, distribution, mobility and trophic level. We then compared katydid hotspots with each other and with recognized biodiversity hotspots. Grid cells within biodiversity hotspots had significantly higher count-based and score-based diversity than non-hotspot grid cells. There was a significant association between the three types of hotspots. Of the count-based measures, endemic species richness was the best surrogate for the others. However, the score-based measure out-performed all count-based diversity measures. Species richness was the least successful surrogate of all. The strong performance of the score-based method for hotspot prediction emphasizes the importance of including species’ natural history information for conservation decision-making, and is easily adaptable to other organisms. Furthermore, these results add empirical support for the efficacy of biodiversity hotspots in conserving non-target organisms. PMID:27631131

  5. A fuzzy pattern matching method based on graph kernel for lithography hotspot detection

    NASA Astrophysics Data System (ADS)

    Nitta, Izumi; Kanazawa, Yuzi; Ishida, Tsutomu; Banno, Koji

    2017-03-01

    In advanced technology nodes, lithography hotspot detection has become one of the most significant issues in design for manufacturability. Recently, machine learning based lithography hotspot detection has been widely investigated, but it has trade-off between detection accuracy and false alarm. To apply machine learning based technique to the physical verification phase, designers require minimizing undetected hotspots to avoid yield degradation. They also need a ranking of similar known patterns with a detected hotspot to prioritize layout pattern to be corrected. To achieve high detection accuracy and to prioritize detected hotspots, we propose a novel lithography hotspot detection method using Delaunay triangulation and graph kernel based machine learning. Delaunay triangulation extracts features of hotspot patterns where polygons locate irregularly and closely one another, and graph kernel expresses inner structure of graphs. Additionally, our method provides similarity between two patterns and creates a list of similar training patterns with a detected hotspot. Experiments results on ICCAD 2012 benchmarks show that our method achieves high accuracy with allowable range of false alarm. We also show the ranking of the similar known patterns with a detected hotspot.

  6. Hotspot motion inferred from mantle flow models: implications on global plate reconstructions

    NASA Astrophysics Data System (ADS)

    Steinberger, B.; O'Connell, R. J.

    2003-04-01

    The Hawaiian hotspot track predicted from a plate circuit, assuming that the Hawaiian hotspot is fixed relative to African hotspots, does not fit the observed track: The divergence is steadily increasing back to 43 Ma, and the predicted track does not show a bend. Here we use a model of plumes distorted by global mantle flow to compute hotspot motion, and test whether this motion can explain the misfit. Computations consistently predict a south- to southeastward motion of the Hawaiian hotspot, and a motion of about 1000 km southward during the past 80 Ma is within the range of model results. Thus, we find that our model of hotspot motion can account for the divergence from 0 to 43 Ma, but can not account for the bend and the track prior to 43 Ma. For this, both a rather sharp change in hotspot motion at 43 Ma, and a westward component of hotspot motion prior to 43 Ma would be required, and neither is predicted in the model. However, a combination of modelled hotspot motion and a relatively modest motion between W and E Antarctica - about 15 degrees clockwise rotation of W vs. E Antarctica - would permit a fit to the Hawaiian track from 80 to 43 My. The required deformation could have been accomplished entirely within continental crust, with rates similar to e.g. present extension in the western U.S., and we will argue that it is not in conflict with, but actually supported by geologic evidence.

  7. Some new results on irradiation characteristics of synthetic quartz crystals and their application to radiation hardening

    NASA Technical Reports Server (NTRS)

    Bahadur, H.; Parshad, R.

    1983-01-01

    The paper reports some new results on irradiation characteristics of synthetic quartz crystals and their application to radiation hardening. The present results show how the frequency shift in quartz crystals can be influenced by heat processing prior to irradiation and how this procedure can lead to radiation hardening for obtaining precise frequencies and time intervals from quartz oscillators in space.

  8. Distribution, congruence, and hotspots of higher plants in China

    NASA Astrophysics Data System (ADS)

    Zhao, Lina; Li, Jinya; Liu, Huiyuan; Qin, Haining

    2016-01-01

    Identifying biodiversity hotspots has become a central issue in setting up priority protection areas, especially as financial resources for biological diversity conservation are limited. Taking China’s Higher Plants Red List (CHPRL), including Bryophytes, Ferns, Gymnosperms, Angiosperms, as the data source, we analyzed the geographic patterns of species richness, endemism, and endangerment via data processing at a fine grid-scale with an average edge length of 30 km based on three aspects of richness information: species richness, endemic species richness, and threatened species richness. We sought to test the accuracy of hotspots used in identifying conservation priorities with regard to higher plants. Next, we tested the congruence of the three aspects and made a comparison of the similarities and differences between the hotspots described in this paper and those in previous studies. We found that over 90% of threatened species in China are concentrated. While a high spatial congruence is observed among the three measures, there is a low congruence between two different sets of hotspots. Our results suggest that biodiversity information should be considered when identifying biological hotspots. Other factors, such as scales, should be included as well to develop biodiversity conservation plans in accordance with the region’s specific conditions.

  9. Distribution, congruence, and hotspots of higher plants in China

    PubMed Central

    Zhao, Lina; Li, Jinya; Liu, Huiyuan; Qin, Haining

    2016-01-01

    Identifying biodiversity hotspots has become a central issue in setting up priority protection areas, especially as financial resources for biological diversity conservation are limited. Taking China’s Higher Plants Red List (CHPRL), including Bryophytes, Ferns, Gymnosperms, Angiosperms, as the data source, we analyzed the geographic patterns of species richness, endemism, and endangerment via data processing at a fine grid-scale with an average edge length of 30 km based on three aspects of richness information: species richness, endemic species richness, and threatened species richness. We sought to test the accuracy of hotspots used in identifying conservation priorities with regard to higher plants. Next, we tested the congruence of the three aspects and made a comparison of the similarities and differences between the hotspots described in this paper and those in previous studies. We found that over 90% of threatened species in China are concentrated. While a high spatial congruence is observed among the three measures, there is a low congruence between two different sets of hotspots. Our results suggest that biodiversity information should be considered when identifying biological hotspots. Other factors, such as scales, should be included as well to develop biodiversity conservation plans in accordance with the region’s specific conditions. PMID:26750244

  10. HIV protein sequence hotspots for crosstalk with host hub proteins.

    PubMed

    Sarmady, Mahdi; Dampier, William; Tozeren, Aydin

    2011-01-01

    HIV proteins target host hub proteins for transient binding interactions. The presence of viral proteins in the infected cell results in out-competition of host proteins in their interaction with hub proteins, drastically affecting cell physiology. Functional genomics and interactome datasets can be used to quantify the sequence hotspots on the HIV proteome mediating interactions with host hub proteins. In this study, we used the HIV and human interactome databases to identify HIV targeted host hub proteins and their host binding partners (H2). We developed a high throughput computational procedure utilizing motif discovery algorithms on sets of protein sequences, including sequences of HIV and H2 proteins. We identified as HIV sequence hotspots those linear motifs that are highly conserved on HIV sequences and at the same time have a statistically enriched presence on the sequences of H2 proteins. The HIV protein motifs discovered in this study are expressed by subsets of H2 host proteins potentially outcompeted by HIV proteins. A large subset of these motifs is involved in cleavage, nuclear localization, phosphorylation, and transcription factor binding events. Many such motifs are clustered on an HIV sequence in the form of hotspots. The sequential positions of these hotspots are consistent with the curated literature on phenotype altering residue mutations, as well as with existing binding site data. The hotspot map produced in this study is the first global portrayal of HIV motifs involved in altering the host protein network at highly connected hub nodes.

  11. Hot-spot mix in ignition-scale implosions on the NIF [Hot-spot mix in ignition-scale implosions on the National Ignition Facility (NIF)

    DOE PAGES

    Regan, S. P.; Epstein, R.; Hammel, B. A.; ...

    2012-03-30

    Ignition of an inertial confinement fusion (ICF) target depends on the formation of a central hot spot with sufficient temperature and areal density. Radiative and conductive losses from the hot spot can be enhanced by hydrodynamic instabilities. The concentric spherical layers of current National Ignition Facility (NIF) ignition targets consist of a plastic ablator surrounding 2 a thin shell of cryogenic thermonuclear fuel (i.e., hydrogen isotopes), with fuel vapor filling the interior volume. The Rev. 5 ablator is doped with Ge to minimize preheat of the ablator closest to the DT ice caused by Au M-band emission from the hohlraummore » x-ray drive. Richtmyer–Meshkov and Rayleigh–Taylor hydrodynamic instabilities seeded by high-mode (50 < t < 200) ablator-surface perturbations can cause Ge-doped ablator to mix into the interior of the shell at the end of the acceleration phase. As the shell decelerates, it compresses the fuel vapor, forming a hot spot. K-shell line emission from the ionized Ge that has penetrated into the hot spot provides an experimental signature of hot-spot mix. The Ge emission from tritium–hydrogen–deuterium (THD) and DT cryogenic targets and gas-filled plastic shell capsules, which replace the THD layer with a massequivalent CH layer, was examined. The inferred amount of hot-spot mix mass, estimated from the Ge K-shell line brightness using a detailed atomic physics code, is typically below the 75 ng allowance for hot-spot mix. Furthermore, predictions of a simple mix model, based on linear growth of the measured surface-mass modulations, are consistent with the experimental results.« less

  12. Hot-spot mix in ignition-scale implosions on the NIF [Hot-spot mix in ignition-scale implosions on the National Ignition Facility (NIF)

    SciTech Connect

    Regan, S. P.; Epstein, R.; Hammel, B. A.; Suter, L. J.; Ralph, J.; Scott, H.; Barrios, M. A.; Bradley, D. K.; Callahan, D. A.; Cerjan, C.; Collins, G. W.; Dixit, S. N.; Doeppner, T.; Edwards, M. J.; Farley, D. R.; Glenn, S.; Glenzer, S. H.; Golovkin, I. E.; Haan, S. W.; Hamza, A.; Hicks, D. G.; Izumi, N.; Kilkenny, J. D.; Kline, J. L.; Kyrala, G. A.; Landen, O. L.; Ma, T.; MacFarlane, J. J.; Mancini, R. C.; McCrory, R. L.; Meezan, N. B.; Meyerhofer, D. D.; Nikroo, A.; Peterson, K. J.; Sangster, T. C.; Springer, P.; Town, R. P. J.

    2012-03-30

    Ignition of an inertial confinement fusion (ICF) target depends on the formation of a central hot spot with sufficient temperature and areal density. Radiative and conductive losses from the hot spot can be enhanced by hydrodynamic instabilities. The concentric spherical layers of current National Ignition Facility (NIF) ignition targets consist of a plastic ablator surrounding 2 a thin shell of cryogenic thermonuclear fuel (i.e., hydrogen isotopes), with fuel vapor filling the interior volume. The Rev. 5 ablator is doped with Ge to minimize preheat of the ablator closest to the DT ice caused by Au M-band emission from the hohlraum x-ray drive. Richtmyer–Meshkov and Rayleigh–Taylor hydrodynamic instabilities seeded by high-mode (50 < t < 200) ablator-surface perturbations can cause Ge-doped ablator to mix into the interior of the shell at the end of the acceleration phase. As the shell decelerates, it compresses the fuel vapor, forming a hot spot. K-shell line emission from the ionized Ge that has penetrated into the hot spot provides an experimental signature of hot-spot mix. The Ge emission from tritium–hydrogen–deuterium (THD) and DT cryogenic targets and gas-filled plastic shell capsules, which replace the THD layer with a massequivalent CH layer, was examined. The inferred amount of hot-spot mix mass, estimated from the Ge K-shell line brightness using a detailed atomic physics code, is typically below the 75 ng allowance for hot-spot mix. Furthermore, predictions of a simple mix model, based on linear growth of the measured surface-mass modulations, are consistent with the experimental results.

  13. High coverage of litho hotspot detection by weak pattern scoring

    NASA Astrophysics Data System (ADS)

    Park, Jinho; Kim, NamJae; Kang, Jae-hyun; Paek, Seung Weon; Kwon, Steve; Shafee, Marwah; Madkour, Kareem; ElManhawy, Wael; Kwan, Joe; Brunet, Jean-Marie

    2015-03-01

    Achieving lithographic printability at advanced nodes (14nm and beyond) can impose significant restrictions on physical design, including large numbers of complex design rule checks (DRC) and compute-intensive detailed process model checking. Early identifying of yield-limiter hotspots is essential for both foundries and designers to significantly improve process maturity. A real challenge is to scan the design space to identify hotspots, and decide the proper course of action regarding each hotspot. Building a scored pattern library with real candidates for hotspots for both foundries and designers is of great value. Foundries are looking for the most used patterns to optimize their technology for and identify patterns that should be forbidden, while designers are looking for the patterns that are sensitive to their neighboring context to perform lithographic simulation with their context to decide if they are hotspots or not.[1] In this paper we propose a framework to data mine designs to obtain set of representative patterns of each design, our aim is to sample the designs at locations that can be potential yield limiting. Though our aim is to keep the total number of patterns as small as possible to limit the complexity, still the designer is free to generate layouts results in several million of patterns that define the whole design space. In order to handle the large number of patterns that represent the design building block constructs, we need to prioritize the patterns according to their importance. The proposed pattern classification methodology depends on giving scores to each pattern according to the severity of hotspots they cause, the probability of their presence in the design and the likelihood of causing a hotspot. The paper also shows how the scoring scheme helps foundries to optimize their master pattern libraries and priorities their efforts in 14nm technology and beyond. Moreover, the paper demonstrates how the hotspot scoring helps in

  14. Where are the lightning hotspots on Earth?

    NASA Astrophysics Data System (ADS)

    Albrecht, R. I.; Goodman, S. J.; Buechler, D. E.; Blakeslee, R. J.; Christian, H. J., Jr.

    2015-12-01

    The first lightning observations from space date from the early 1960s and more than a dozen spacecraft orbiting the Earth have flown instruments that recorded lightning signals from thunderstorms over the past 45 years. In this respect, the Tropical Rainfall Measuring Mission (TRMM) Lightning Imaging Sensor (LIS), having just completed its mission (1997-2015), provides the longest and best total (intracloud and cloud-to-ground) lightning data base over the tropics.We present a 16 year (1998-2013) reprocessed data set to create very high resolution (0.1°) TRMM LIS total lightning climatology. This detailed very high resolution climatology is used to identify the Earth's lightning hotspots and other regional features. Earlier studies located the lightning hotspot within the Congo Basin in Africa, but our very high resolution lightning climatology found that the highest lightning flash rate on Earth actually occurs in Venezuela over Lake Maracaibo, with a distinct maximum during the night. The higher resolution dataset clearly shows that similar phenomenon also occurs over other inland lakes with similar conditions, i.e., locally forced convergent flow over a warm lake surface which drives deep nocturnal convection. Although Africa does not have the top lightning hotspot, it comes in a close second and it is the continent with the highest number of lightning hotspots, followed by Asia, South America, North America, and Oceania. We also present climatological maps for local hour and month of lightning maxima, along with a ranking of the highest five hundred lightning maxima, focusing discussion on each continent's 10 highest lightning maxima. Most of the highest continental maxima are located near major mountain ranges, revealing the importance of local topography in thunderstorm development. These results are especially relevant in anticipation of the upcoming availability of continuous total lightning observations from the Geostationary Lightning Mapping (GLM

  15. Hotspots within hotspots? Hammerhead shark movements around Wolf Island, Galapagos Marine Reserve.

    PubMed

    Hearn, Alex; Ketchum, James; Klimley, A Peter; Espinoza, Eduardo; Peñaherrera, Cesar

    2010-01-01

    Are pelagic species such as sharks and tuna distributed homogenously or heterogeneously in the oceans? Large assemblages of these species have been observed at seamounts and offshore islands in the eastern tropical Pacific, which are considered hotspots of pelagic biodiversity. Is the species distribution uniform at these hotspots or do species aggregate at a finer spatial scale at these sites? We employed three techniques to demonstrate that the aggregations of scalloped hammerhead sharks, Sphyrna lewini, and other pelagic species were confined to the southeastern corner of Wolf Island in the Galapagos Marine Reserve. Coded ultrasonic transmitters were placed on individuals at this site and at another aggregation site at Darwin Island, separated from Wolf by 40 km, and they were detected by monitors moored at the southeastern corner of Wolf Island and rarely by monitors deployed at other sites around the island. Hammerhead sharks, carrying depth-sensing continual transmitters, were tracked for two-day periods in a vessel and shown to reside a disproportionately large fraction of their time at the southeastern corner. Visual censuses were carried out seasonally at the eight monitor sites at Wolf Island, recording the abundance of one species of tuna, four species of jacks, and a number of other species. The highest diversity and abundance of these species occurred in the southeastern corner of the island. Our results support the use of hammerhead sharks as indicator and umbrella species for pelagic hotspots on a fine scale.

  16. Recent results on celestial gamma radiation from SMM

    NASA Technical Reports Server (NTRS)

    Share, Gerald H.

    1991-01-01

    Observations made by the Gamma Ray Spectrometer on board the SMM are described. Recent results reported include observations and analyses of gamma-ray lines from Co-56 produced in supernovae, observations of the temporal variation of the 511 keV line observed during Galactic center transits, and measurements of the diffuse Galactic spectrum from 0.3 to 8.5 MeV. The work in progress includes measurements of the distribution of Galactic Al-26, observations to place limits on Galactic Ti-44 and Fe-60 and on Be-7 produced in novae, and searches for a characteristic gamma-ray emission from pair plasmas, a 2.223 MeV line emission, limits on deexcitation lines from interstellar C and O, and gamma-ray bursts.

  17. Recent results on celestial gamma radiation from SMM

    NASA Technical Reports Server (NTRS)

    Share, Gerald H.

    1991-01-01

    Observations made by the Gamma Ray Spectrometer on board the SMM are described. Recent results reported include observations and analyses of gamma-ray lines from Co-56 produced in supernovae, observations of the temporal variation of the 511 keV line observed during Galactic center transits, and measurements of the diffuse Galactic spectrum from 0.3 to 8.5 MeV. The work in progress includes measurements of the distribution of Galactic Al-26, observations to place limits on Galactic Ti-44 and Fe-60 and on Be-7 produced in novae, and searches for a characteristic gamma-ray emission from pair plasmas, a 2.223 MeV line emission, limits on deexcitation lines from interstellar C and O, and gamma-ray bursts.

  18. Results of microwave oven radiation leakage surveys at Fermilab

    SciTech Connect

    Miller, T.M.

    1987-01-01

    This report describes the results of routine microwave oven leakage surveys which were conducted at Fermi National Accelerator Laboratory (Fermilab) between 1974 and 1985. A total of 80 ovens representing 250 oven-years of operation were examined. The mean maximum leakage at any point 5 cm from the surface was 0.20 x/ 3.1 mW/cm/sup 2/. Although there was a great deal of scatter in sequential measurements for individual ovens, it appears that leakage tends to increase with oven age. The mean logarithmic rate of increase for the 55 ovens with usable data was 0.21 per year. Case histories of ovens leaking in excess of the standard were examined, and improvements in leakage monitoring programs are suggested.

  19. Topolgy Agnostic Hot-Spot Avoidance with InfiniBand

    SciTech Connect

    Vishnu, Abhinav; Koop, Matthew J.; Moody, Adam; Mamidala, Amith; Narravula, Sundeep; Panda, Dhabaleswar K.

    2009-03-01

    InfiniBand has become a very popular interconnect, due to its advanced features and open standard. Large scale InfiniBand clusters are becoming very popular, as reflected by the TOP 500 supercomputer rankings. However, even with popular topologies like constant bi-section bandwidth Fat Tree, hot-spots may occur with InfiniBand, due to inappropriate configuration of network paths, presence of other jobs in the network and un-availability of adaptive routing. In this paper, we present a hot-spot avoidance layer (HSAL) for InfiniBand, which provides hot-spot avoidance using path bandwidth estimation and multi-pathing using LMC mechanism, without taking the network topology into account. We propose an adaptive striping policy with batch based striping and sorting approach, for efficient utilization of disjoint network paths. Integration of HSAL with MPI, the de facto programming model of clusters, shows promising results with collective communication primitives and MPI applications.

  20. 29 years of surprises from hotspots: A personal perspective

    NASA Astrophysics Data System (ADS)

    Students Of Eao, .; Okal, E. A.

    2003-12-01

    I arrived at Caltech on 26 August 1974, to begin my graduate studies at the Seismo Lab, then under the Directorship of Don L. Anderson. These were the days, among other topics, of Don's famous multilingual footnote on the "definition..., antecedents..., supporters and detractors" of the concept of "plume" [GSA Bull., 86, p. 1593, 1975], and even though I was not to set foot on a hotspot island until my first trip to Tahiti in December 1977 (those stopovers at Keflavik on the 199-dollar Loftleidir runs did not really count), I quickly acquired a mild form of Don's contagious fascination for the activity and structure of hotspots. As a tribute to Don, I have chosen to recap here a few surprising results obtained, with the help of my students, past and present, over several decades of work on the seismological sources and structures in the neighborhood of hotspot islands.

  1. Prdm9 controls activation of mammalian recombination hotspots.

    PubMed

    Parvanov, Emil D; Petkov, Petko M; Paigen, Kenneth

    2010-02-12

    Mammalian meiotic recombination, which preferentially occurs at specialized sites called hotspots, ensures the orderly segregation of meiotic chromosomes and creates genetic variation among offspring. A locus on mouse chromosome 17, which controls activation of recombination at multiple distant hotspots, has been mapped within a 181-kilobase interval, three of whose genes can be eliminated as candidates. The remaining gene, Prdm9, codes for a zinc finger containing histone H3K4 trimethylase that is expressed in early meiosis and whose deficiency results in sterility in both sexes. Mus musculus exhibits five alleles of Prdm9; human populations exhibit two predominant alleles and multiple minor alleles. The identification of Prdm9 as a protein regulating mammalian recombination hotspots initiates molecular studies of this important biological control system.

  2. Cold Fusion at Hotspots

    NASA Astrophysics Data System (ADS)

    Natland, J. H.

    2009-12-01

    with average melt temperature of ~1100C, the same temperature as given by Ca-in-orthopyroxene of the harzburgites. Cold ambient mantle draws heat from ascending magma, forcing differentiation at depth. Magma with TP greater by 200C than primitive basalt at spreading ridges does not exist at any of these places. TP does not constrain temperature of the mantle below the depth of melt extraction. High and variable 3He/4He at all these places may result from volatile incorporation from old harzburgite through which magmas must ascend. Poustovetov, A., and Roeder, P.L., 2000. Canad. Min. 39: 309-317.

  3. An Orexin Hotspot in Ventral Pallidum Amplifies Hedonic ‘Liking' for Sweetness

    PubMed Central

    Ho, Chao-Yi; Berridge, Kent C

    2013-01-01

    Orexin (hypocretin) is implicated in stimulating appetite as well as arousal, and in both food reward and drug reward. The ventral pallidum (VP) receives orexin projections from lateral hypothalamus neurons (LH), and orexin terminals are especially dense in the posterior half of VP, which is also the location of an opioid hedonic hotspot. The VP hotspot is a roughly cubic-millimeter site where mu opioid stimulation can amplify the hedonic impact of sweetness, expressed as an increase in ‘liking' reactions to sucrose taste. The anatomical overlap in posterior VP between opioid hotspot and orexin inputs raises the possibility that the hedonic hotspot might allow orexin to amplify ‘liking' too. We examined whether microinjections of orexin-A into the VP hotspot enhance the hedonic impact of sucrose, as assessed via affective taste reactivity measures of ‘liking' reactions, and additionally compared effects at nearby sites in adjacent LH and extended amygdala. Taste reactivity results indicated that orexin stimulation specifically in the VP hotspot nearly doubled the magnitude of positive ‘liking' reactions elicited by the taste of sucrose. Mapping results for localization of function, aided by Fos plume measures of the local spread of orexin impact, suggested that hedonic enhancement was generated by essentially the same cubic-millimeter of posterior VP previously identified as the opioid hotspot. By contrast, microinjection sites in the anterior half of VP, or in LH or extended amygdala, generally failed to produce any hedonic enhancement. We conclude that an orexin hedonic hotspot exists in posterior VP, with similar boundaries to the opioid hotspot. An orexin hedonic hotspot may permit regulatory hypothalamic circuitry to make foods more ‘liked' during hunger by acting through VP. Dysfunction in a VP orexin hotspot in addiction or mood disorders might also contribute to some types of affective psychopathology. PMID:23463152

  4. Radiation Testing on State-of-the-Art CMOS: Challenges, Plans, and Preliminary Results

    NASA Technical Reports Server (NTRS)

    LaBel, Kenneth A.; Cohn, Lewis M.

    2009-01-01

    At GOMAC 2007 and 2008, we discussed a variety of challenges for radiation testing of modern semiconductor devices and technologies [1, 2]. In this presentation, we provide more specific details in this on-going investigation focusing on out-of-the-box lessons observed for providing radiation effects assurances as well as preliminary test results.

  5. Global mammal distributions, biodiversity hotspots, and conservation

    PubMed Central

    Ceballos, Gerardo; Ehrlich, Paul R.

    2006-01-01

    Hotspots, which have played a central role in the selection of sites for reserves, require careful rethinking. We carried out a global examination of distributions of all nonmarine mammals to determine patterns of species richness, endemism, and endangerment, and to evaluate the degree of congruence among hotspots of these three measures of diversity in mammals. We then compare congruence of hotspots in two animal groups (mammals and birds) to assess the generality of these patterns. We defined hotspots as the richest 2.5% of cells in a global equal-area grid comparable to 1° latitude × 1° longitude. Hotspots of species richness, “endemism,” and extinction threat were noncongruent. Only 1% of cells and 16% of species were common to the three types of mammalian hotspots. Congruence increased with increases in both the geographic scope of the analysis and the percentage of cells defined as being hotspots. The within-mammal hotspot noncongruence was similar to the pattern recently found for birds. Thus, assigning global conservation priorities based on hotspots is at best a limited strategy. PMID:17164331

  6. Global mammal distributions, biodiversity hotspots, and conservation.

    PubMed

    Ceballos, Gerardo; Ehrlich, Paul R

    2006-12-19

    Hotspots, which have played a central role in the selection of sites for reserves, require careful rethinking. We carried out a global examination of distributions of all nonmarine mammals to determine patterns of species richness, endemism, and endangerment, and to evaluate the degree of congruence among hotspots of these three measures of diversity in mammals. We then compare congruence of hotspots in two animal groups (mammals and birds) to assess the generality of these patterns. We defined hotspots as the richest 2.5% of cells in a global equal-area grid comparable to 1 degrees latitude x 1 degrees longitude. Hotspots of species richness, "endemism," and extinction threat were noncongruent. Only 1% of cells and 16% of species were common to the three types of mammalian hotspots. Congruence increased with increases in both the geographic scope of the analysis and the percentage of cells defined as being hotspots. The within-mammal hotspot noncongruence was similar to the pattern recently found for birds. Thus, assigning global conservation priorities based on hotspots is at best a limited strategy.

  7. Geographic Hotspots of Critical National Infrastructure.

    PubMed

    Thacker, Scott; Barr, Stuart; Pant, Raghav; Hall, Jim W; Alderson, David

    2017-06-12

    Failure of critical national infrastructures can result in major disruptions to society and the economy. Understanding the criticality of individual assets and the geographic areas in which they are located is essential for targeting investments to reduce risks and enhance system resilience. Within this study we provide new insights into the criticality of real-life critical infrastructure networks by integrating high-resolution data on infrastructure location, connectivity, interdependence, and usage. We propose a metric of infrastructure criticality in terms of the number of users who may be directly or indirectly disrupted by the failure of physically interdependent infrastructures. Kernel density estimation is used to integrate spatially discrete criticality values associated with individual infrastructure assets, producing a continuous surface from which statistically significant infrastructure criticality hotspots are identified. We develop a comprehensive and unique national-scale demonstration for England and Wales that utilizes previously unavailable data from the energy, transport, water, waste, and digital communications sectors. The testing of 200,000 failure scenarios identifies that hotspots are typically located around the periphery of urban areas where there are large facilities upon which many users depend or where several critical infrastructures are concentrated in one location. © 2017 Society for Risk Analysis.

  8. A Method for Improving Hotspot Directional Signatures in BRDF Models Used for MODIS

    NASA Technical Reports Server (NTRS)

    Jiao, Ziti; Schaaf, Crystal B.; Dong, Yadong; Roman, Miguel; Hill, Michael J.; Chen, Jing M.; Wang, Zhuosen; Zhang, Hu; Saenz, Edward; Poudyal, Rajesh; hide

    2016-01-01

    The semi-empirical, kernel-driven, linear RossThick-LiSparseReciprocal (RTLSR) Bidirectional Reflectance Distribution Function (BRDF) model is used to generate the routine MODIS BRDFAlbedo product due to its global applicability and the underlying physics. A challenge of this model in regard to surface reflectance anisotropy effects comes from its underestimation of the directional reflectance signatures near the Sun illumination direction; also known as the hotspot effect. In this study, a method has been developed for improving the ability of the RTLSR model to simulate the magnitude and width of the hotspot effect. The method corrects the volumetric scattering component of the RTLSR model using an exponential approximation of a physical hotspot kernel, which recreates the hotspot magnitude and width using two free parameters (C(sub 1) and C(sub 2), respectively). The approach allows one to reconstruct, with reasonable accuracy, the hotspot effect by adjusting or using the prior values of these two hotspot variables. Our results demonstrate that: (1) significant improvements in capturing hotspot effect can be made to this method by using the inverted hotspot parameters; (2) the reciprocal nature allow this method to be more adaptive for simulating the hotspot height and width with high accuracy, especially in cases where hotspot signatures are available; and (3) while the new approach is consistent with the heritage RTLSR model inversion used to estimate intrinsic narrowband and broadband albedos, it presents some differences for vegetation clumping index (CI) retrievals. With the hotspot-related model parameters determined a priori, this method offers improved performance for various ecological remote sensing applications; including the estimation of canopy structure parameters.

  9. Mantle transition zone thickness beneath the Yellowstone hotspot

    NASA Astrophysics Data System (ADS)

    Zurek, B. D.; Dueker, K.

    2002-12-01

    The Yellowstone hotspot is one of the largest continental hotspots, however whether the hotspot actively derives from a lower mantle plume or an upper mantle convective instability is not constrained. The plume model is supported by the 2-3 cm/yr volcanic age progression approximately parallel to the absolute North American plate motion and an elevated He3/He4 signature. Correspondingly, evidence against a plume model derives from the lack of dynamic topographic uplift (Lowry et al., 1998), absence of a low velocity anomaly below 200 km depth (Dueker et al., 2001) and shear-wave splits that show no plume related flow anomalies (Waite et al., 2002). To better constrain the origin of the hotspot, The Yellowstone Intermountain Seismic Array (YISA) with 47 PASSCAL broad-band seismometers was deployed for one year covering a region 250 km in radius from the center of the Yellowstone hotspot. Here we present images of the mantle transition zone from receiver function common conversion point imaging. Lateral velocity heterogeneity corrections are applied to the receiver functions using the teleseismic P-times calculated from the array. The mantle transition zone is composed of the 410 and 660 km discontinuities, these discontinuities are generally regarded to derive from phase changes that have opposite Clapeyron slopes. Thus if the mantle is assumed to be compositional homogenous, >100 degree lateral thermal gradients are resolvable from transition zone thickness maps. Preliminary results show that the transition zone beneath the Yellowstone hotspot has a mean thickness of 245 km with 20 km of variation across the array. The mean values of the 410 and 660 km discontinuities are, 412 km and 660 km, with 16 and 14 km of topography, respectively. The processes that could produce this topography are the focus of our current research.

  10. Macroscopic hotspots identification: A Bayesian spatio-temporal interaction approach.

    PubMed

    Dong, Ni; Huang, Helai; Lee, Jaeyoung; Gao, Mingyun; Abdel-Aty, Mohamed

    2016-07-01

    This study proposes a Bayesian spatio-temporal interaction approach for hotspot identification by applying the full Bayesian (FB) technique in the context of macroscopic safety analysis. Compared with the emerging Bayesian spatial and temporal approach, the Bayesian spatio-temporal interaction model contributes to a detailed understanding of differential trends through analyzing and mapping probabilities of area-specific crash trends as differing from the mean trend and highlights specific locations where crash occurrence is deteriorating or improving over time. With traffic analysis zones (TAZs) crash data collected in Florida, an empirical analysis was conducted to evaluate the following three approaches for hotspot identification: FB ranking using a Poisson-lognormal (PLN) model, FB ranking using a Bayesian spatial and temporal (B-ST) model and FB ranking using a Bayesian spatio-temporal interaction (B-ST-I) model. The results show that (a) the models accounting for space-time effects perform better in safety ranking than does the PLN model, and (b) the FB approach using the B-ST-I model significantly outperforms the B-ST approach in correctly identifying hotspots by explicitly accounting for the space-time variation in addition to the stable spatial/temporal patterns of crash occurrence. In practice, the B-ST-I approach plays key roles in addressing two issues: (a) how the identified hotspots have evolved over time and (b) the identification of areas that, whilst not yet hotspots, show a tendency to become hotspots. Finally, it can provide guidance to policy decision makers to efficiently improve zonal-level safety. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Early Results from the Advanced Radiation Protection Thick GCR Shielding Project

    NASA Technical Reports Server (NTRS)

    Norman, Ryan B.; Clowdsley, Martha; Slaba, Tony; Heilbronn, Lawrence; Zeitlin, Cary; Kenny, Sean; Crespo, Luis; Giesy, Daniel; Warner, James; McGirl, Natalie; hide

    2017-01-01

    The Advanced Radiation Protection Thick Galactic Cosmic Ray (GCR) Shielding Project leverages experimental and modeling approaches to validate a predicted minimum in the radiation exposure versus shielding depth curve. Preliminary results of space radiation models indicate that a minimum in the dose equivalent versus aluminum shielding thickness may exist in the 20-30 g/cm2 region. For greater shield thickness, dose equivalent increases due to secondary neutron and light particle production. This result goes against the long held belief in the space radiation shielding community that increasing shielding thickness will decrease risk to crew health. A comprehensive modeling effort was undertaken to verify the preliminary modeling results using multiple Monte Carlo and deterministic space radiation transport codes. These results verified the preliminary findings of a minimum and helped drive the design of the experimental component of the project. In first-of-their-kind experiments performed at the NASA Space Radiation Laboratory, neutrons and light ions were measured between large thicknesses of aluminum shielding. Both an upstream and a downstream shield were incorporated into the experiment to represent the radiation environment inside a spacecraft. These measurements are used to validate the Monte Carlo codes and derive uncertainty distributions for exposure estimates behind thick shielding similar to that provided by spacecraft on a Mars mission. Preliminary results for all aspects of the project will be presented.

  12. Paleo-drainage basin connectivity predicts evolutionary relationships across three Southeast Asian biodiversity hotspots.

    PubMed

    de Bruyn, Mark; Rüber, Lukas; Nylinder, Stephan; Stelbrink, Björn; Lovejoy, Nathan R; Lavoué, Sébastien; Tan, Heok Hui; Nugroho, Estu; Wowor, Daisy; Ng, Peter K L; Siti Azizah, M N; Von Rintelen, Thomas; Hall, Robert; Carvalho, Gary R

    2013-05-01

    Understanding factors driving diversity across biodiversity hotspots is critical for formulating conservation priorities in the face of ongoing and escalating environmental deterioration. While biodiversity hotspots encompass a small fraction of Earth's land surface, more than half the world's plants and two-thirds of terrestrial vertebrate species are endemic to these hotspots. Tropical Southeast (SE) Asia displays extraordinary species richness, encompassing four biodiversity hotspots, though disentangling multiple potential drivers of species richness is confounded by the region's dynamic geological and climatic history. Here, we use multilocus molecular genetic data from dense multispecies sampling of freshwater fishes across three biodiversity hotspots, to test the effect of Quaternary climate change and resulting drainage rearrangements on aquatic faunal diversification. While Cenozoic geological processes have clearly shaped evolutionary history in SE Asian halfbeak fishes, we show that paleo-drainage re-arrangements resulting from Quaternary climate change played a significant role in the spatiotemporal evolution of lowland aquatic taxa, and provide priorities for conservation efforts.

  13. Yellowstone hotspot-continental lithosphere interaction

    NASA Astrophysics Data System (ADS)

    Jean, Marlon M.; Hanan, Barry B.; Shervais, John W.

    2014-03-01

    The Snake River Plain represents 17 m.y. of volcanic activity that took place as the North American continent migrated over a relatively fixed magma source, or hotspot. We present new Pb, Sr, and Nd data for a suite of 25 basalts collected from Western and Central Snake River Plain (SRP). The new isotope data, combined with previously published data from the SRP, provide a traverse of the Wyoming craton margin, from the 87Sr/86Sr = 0.706 line boundary of western SRP with Phanerozoic accreted terranes, east through the central and eastern SRP, to the Yellowstone Plateau. Low-K basalts from the western SRP, overlain by high-K basalts, provide a temporal record of regional source variation from ∼16.8 to 0.2 Ma. Principal Component Analysis (PCA) of the new and previously published SRP basalt Pb isotopes reveals that >97% of the total variability is accounted for by mixing between three end-members and is consistent with a sublithospheric Yellowstone hotspot mantle source with a radiogenic isotope composition similar to the mantle source of the early Columbia River Basalt Group (CRBG) and two continental lithosphere end-members, heterogeneous in age and composition. We use the SRP Pb, Sr, and Nd isotope data to model the Yellowstone Hotspot-continental lithosphere interaction by three component mixing between two continental lithospheric components, Archean lithosphere (CL1) that represents older lithosphere underlying the Yellowstone Plateau in the east, and Paleoproterozoic lithosphere (CL2) representing the younger lithosphere underlying the SRP in the west near the craton margin, and a sublithospheric end-member, representing the Yellowstone hotspot (PL). The results suggest a continuous flow of PL material westward as the NA continental lithosphere migrated over the upwelling hotspot along a shoaling gradient in the sub-continental mantle lithosphere. The model shows a decrease in Total Lithosphere end-members (CL1 + CL2) and the Lithosphere Ratio (CL1/CL2

  14. Geochemical asymmetry of the Crozet hotspot

    NASA Astrophysics Data System (ADS)

    Bézos, Antoine; Pimbert, Anthony; Segard, Mélanie; Hémond, Christophe; Guivel, Christèle; Delpech, Guillaume; Beucler, Eric; La, Carole

    2014-05-01

    The Crozet archipelago (Indian Ocean) includes 5 islands showing contemporaneous volcanism and defining two geographical groups: the Eastern group includes the Possession and Est Islands, and the western group the Pingouins, Cochons and Apôtre Islands. The few Crozet samples that have been analyzed for their isotopic compositions (Possession: N=9; Est: N=15; Pingouins: N=13) reveal the presence of geochemical heterogeneities within the Crozet hotspot. In this study we present new Sr-Nd-Pb-Hf isotopic compositions of 20 lavas samples from the Possession Island. The isotopic compositions, which display limited but significant variations, are characterized by intermediate values (87Sr/86Sr = 0.703972 to 0.704986; 143Nd/144Nd = 0.512822 to 0.512873; 176Hf/177Hf = 0.282959 to 0.283100; 206Pb/204Pb = 18.8099 to 19.1660) akin to the 'C' component. As mentioned by previous studies, lavas from the Possession and Est islands (eastern Islands) display comparable isotopic compositions. The western Pingouins Island lavas denote from Possession-Est lavas by having (for example) lower 87Sr/86Sr and higher 206Pb/204Pb ratios, approaching therefore the Fozo isotopic domain. The most striking results displayed by Crozet data, is the existence of two parallels arrays in the 206Pb/204Pb vs 208Pb/204Pb diagram. For a given 206Pb/204Pb ratio, Possession-Est lavas display higher 208Pb/204Pb ratio compared to Pingouins data. These linear isotopic arrays indicate significant heterogeneity within each of the two trends, both having distinct radiogenic and least radiogenic lead end-members. This observation strongly disagrees with the model of simple binary mixing between the Possession-Est and the Pingouins components proposed by Breton et al., (2013). We first propose to model the Possession-Est radiogenic lead end-members by recycling in the Crozet hotspot source 1Gy oceanic crust with ~2% sediments. The Fozo-like signature of Pingouins lavas may be obtained with a similar model that

  15. Using pattern matching to increase performance in hotspot fixing flows

    NASA Astrophysics Data System (ADS)

    Falch, Bradley J.; Baek, Seung-Hee; Tsai, John; Ji, Mingchao; Zhu, Jun

    2017-03-01

    As feature sizes and pitches continue to decrease, more complex correction algorithms are needed to solve increasingly difficult geometric configurations. Usage of these more complex algorithms results in unacceptably long time-to-mask when applied to an entire design. In many cases, the more complex algorithms are only required in a small percentage of areas of the entire design, and these areas are not always known prior to tapeout. Hotspot fixing (HSF) flows are increasingly used to fix these hotspot areas to minimize errors and decrease time-to-mask. These flows involve "recorrecting" a design, using the previous correction output as the input to the HSF flow. This input file contains a hierarchy that was optimized for the original correction. Hotspot areas are frequently smaller than the original correction areas and frequently repeat in unique cell outputs of the original correction, so the optimal hierarchy for a HSF fix flow may be very different from the original correction. A new hierarchy, optimized for HSF, is difficult to form from the corrected output. This paper describes the usage of pattern-matching to regain hierarchical compression for identical hotspot areas that are not repeating cells in the original correction. Using this pattern-matching HSF flow, turnaround time for the hotspot fixing can be more than 50X faster than re-using the original correction's hierarchy for complex HSF methods. These significant gains can be achieved in spite of the additional complexity it can add to the flow. In the case where simpler/faster HSF correction methods are used, significant turnaround time gains can still be made by using this pattern matching technique. Hotspot fixing methodologies are increasingly deployed during tapeouts as a means to optimize the tradeoffs between complex, highly accurate correction methods and faster methods that are sufficient for most pattern areas.1 However, pattern database hierarchies may not be optimum for these hotspot

  16. Some results of test beam studies of Transition Radiation Detector prototypes at CERN

    NASA Astrophysics Data System (ADS)

    Tikhomirov, V. O.; Brooks, T.; Joos, M.; Rembser, C.; Celebi, E.; Gurbuz, S.; Cetin, S. A.; Konovalov, S. P.; Zhukov, K.; Fillipov, K. A.; Romaniouk, A.; Smirnov, S. Yu; Teterin, P. E.; Vorobev, K. A.; Boldyrev, A. S.; Maevsky, A.; Derendarz, D.

    2017-01-01

    Operating conditions and challenging demands of present and future accelerator experiments result in new requirements on detector systems. There are many ongoing activities aimed to develop new technologies and to improve the properties of detectors based on existing technologies. Our work is dedicated to development of Transition Radiation Detectors (TRD) suitable for different applications. In this paper results obtained in beam tests at SPS accelerator at CERN with the TRD prototype based on straw technology are presented. TRD performance was studied as a function of thickness of the transition radiation radiator and working gas mixture pressure.

  17. Atmospheric Ionizing Radiation (AIR): Analysis, Results, and Lessons Learned From the June 1997 ER-2 Campaign

    NASA Technical Reports Server (NTRS)

    Wilson, J. W. (Editor); Jones, I. W. (Editor); Maiden, D. L. (Editor); Goldhagen, P. (Editor)

    2003-01-01

    The United States initiated a program to assess the technology required for an environmentally safe and operationally efficient High Speed Civil Transport (HSCT) for entrance on the world market after the turn of the century. Due to the changing regulations on radiation exposures and the growing concerns over uncertainty in our knowledge of atmospheric radiations, the NASA High Speed Research Project Office (HSRPO) commissioned a review of "Radiation Exposure and High-Altitude Flight" by the National Council on Radiation Protection and Measurements (NCRP). On the basis of the NCRP recommendations, the HSRPO funded a flight experiment to resolve the environmental uncertainty in the atmospheric ionizing radiation levels as a step in developing an approach to minimize the radiation impact on HSCT operations. To minimize costs in this project, an international investigator approach was taken to assure coverage with instrument sensitivity across the range of particle types and energies to allow unique characterization of the diverse radiation components. The present workshop is a result of the flight measurements made at the maximum intensity of the solar cycle modulated background radiation levels during the month of June 1997.

  18. Hotspot sequential pattern visualization in peatland of Sumatera and Kalimantan using shiny framework

    NASA Astrophysics Data System (ADS)

    Abriantini, G.; Sitanggang, I. S.; Trisminingsih, R.

    2017-01-01

    Fires on peatland frequently occurred in Sumatra and Kalimantan. Fires on peatland can be identified by hotspot sequential patterns. Sequential pattern mining is one of data mining techniques that can be used to analyse hotspot sequential patterns. Sequential pattern discovery equivalent classes (SPADE) algorithm can be applied to extract hotspot sequential patterns. The objectives of this work are: 1) to obtain hotspot sequential pattern in Sumatra and Kalimantan in 2014 and 2015, and 2) to develop a web based application using Shiny framework that is available in R package for hotspot sequential pattern visualization in peatland of Sumatra and Kalimantan. Hotspot sequential patterns were obtained using minimum support of 0.01 with the focus of analysis is the hotspot sequences with length two or more events. This work generated as many 89 sequences with length 2 or more in Sumatra in 2014, 147 sequences in Sumatra in 2015, 48 sequences in Kalimantan in 2014, and 51 sequences in Kalimantan in 2015. Hotspot sequential patterns are visualized based on peatland’s characteristics, weather, and social economy. The features in this web based application have been tested and the results show that all features work properly according to the test scenario.

  19. Some new results on the frequency characteristics on quartz crystals irradiated by ionizing and particle radiations

    NASA Technical Reports Server (NTRS)

    Bahadur, H.; Parshad, R.

    1981-01-01

    The frequency behavior of AT-cut quartz crystals irradiated by X -, gamma rays and fast neutrons. Initial instability in frequency for gamma and neutron irradiated crystals was found. All the different radiations first give a negative frequency shift at lower doses which are followed by positive frequency shift for increased doses. Results are explained in terms of the fundamental crystal structure. Applications of the frequency results for radiation hardening are proposed.

  20. HotSpot Software Configuration Management Plan

    SciTech Connect

    Walker, H; Homann, S G

    2009-03-12

    This Software Configuration Management Plan (SCMP) describes the software configuration management procedures used to ensure that the HotSpot dispersion model meets the requirements of its user base, which includes: (1) Users of the PC version of HotSpot for consequence assessment, hazard assessment and safety analysis calculations; and (2) Users of the NARAC Web and iClient software tools, which allow users to run HotSpot for consequence assessment modeling These users and sponsors of the HotSpot software and the organizations they represent constitute the intended audience for this document. This plan is intended to meet Critical Recommendations 1 and 3 from the Software Evaluation of HotSpot and DOE Safety Software Toolbox Recommendation for inclusion of HotSpot in the Department of Energy (DOE) Safety Software Toolbox. HotSpot software is maintained for the Department of Energy Office of Emergency Operations by the National Atmospheric Release Advisory Center (NARAC) at Lawrence Livermore National Laboratory (LLNL). An overview of HotSpot and NARAC are provided.

  1. HotSpot Software Test Plan

    SciTech Connect

    Walker, H; Homann, S G

    2009-03-12

    This Software Test Plan (STP) describes the procedures used to verify and validate that the HotSpot Health Physics Codes meet the requirements of its user base, which includes: (1) Users of the PC version of HotSpot conducting consequence assessment, hazard assessment and safety analysis calculations; and (2) Users of the NARAC Web and iClient software tools, which allow users to run HotSpot for consequence assessment modeling. This plan is intended to meet Critical Recommendation 2 from the Software Evaluation of HotSpot and DOE Safety Software Toolbox Recommendation for inclusion of HotSpot in the Department of Energy (DOE) Safety Software Toolbox. These users and sponsors of the HotSpot software and the organizations they represent constitute the intended audience for this document. HotSpot software is maintained for the Department of Energy Office of Emergency Operations by the National Atmospheric Release Advisory Center (NARAC) at Lawrence Livermore National Laboratory (LLNL). An overview of HotSpot and NARAC are provided.

  2. Cloud Computing Application for Hotspot Clustering Using Recursive Density Based Clustering (RDBC)

    NASA Astrophysics Data System (ADS)

    Santoso, Aries; Khiyarin Nisa, Karlina

    2016-01-01

    Indonesia has vast areas of tropical forest, but are often burned which causes extensive damage to property and human life. Monitoring hotspots can be one of the forest fire management. Each hotspot is recorded in dataset so that it can be processed and analyzed. This research aims to build a cloud computing application which visualizes hotspots clustering. This application uses the R programming language with Shiny web framework and implements Recursive Density Based Clustering (RDBC) algorithm. Clustering is done on hotspot dataset of the Kalimantan Island and South Sumatra Province to find the spread pattern of hotspots. The clustering results are evaluated using the Silhouette's Coefficient (SC) which yield best value 0.3220798 for Kalimantan dataset. Clustering pattern are displayed in the form of web pages so that it can be widely accessed and become the reference for fire occurrence prediction.

  3. PRDM9 is a major determinant of meiotic recombination hotspots in humans and mice.

    PubMed

    Baudat, F; Buard, J; Grey, C; Fledel-Alon, A; Ober, C; Przeworski, M; Coop, G; de Massy, B

    2010-02-12

    Meiotic recombination events cluster into narrow segments of the genome, defined as hotspots. Here, we demonstrate that a major player for hotspot specification is the Prdm9 gene. First, two mouse strains that differ in hotspot usage are polymorphic for the zinc finger DNA binding array of PRDM9. Second, the human consensus PRDM9 allele is predicted to recognize the 13-mer motif enriched at human hotspots; this DNA binding specificity is verified by in vitro studies. Third, allelic variants of PRDM9 zinc fingers are significantly associated with variability in genome-wide hotspot usage among humans. Our results provide a molecular basis for the distribution of meiotic recombination in mammals, in which the binding of PRDM9 to specific DNA sequences targets the initiation of recombination at specific locations in the genome.

  4. A Radiation Safety Training Program Results in Reduced Radiation Exposure for Orthopaedic Residents Using the Mini C-arm.

    PubMed

    Gendelberg, David; Hennrikus, William; Slough, Jennifer; Armstrong, Douglas; King, Steven

    2016-02-01

    Fluoroscopy during fracture reduction allows a physician to assess fractures and immediately treat a pediatric patient. However, concern regarding the effects of radiation exposure has led us to find ways to keep radiation exposures as low as reasonably achievable. One potentially simple way, which to our knowledge has not been explored, to decrease radiation exposure is through formal education before mini C-arm use. We questioned whether a radiation safety educational program decreases radiation (1) time and (2) exposure among residents and patients. This is a retrospective study in which second-year residents underwent a 3-hour educational program regarding mini C-arm use and radiation safety taught by our institution's health physics department. We evaluated the records of all patients who underwent a pediatric both-bone forearm or distal radius fracture reduction in the emergency department 3 months before the educational program or after the program. To be included in the study, records included simple both-bone forearm fractures, simple distal radius fractures, and patient age younger than 18 years, and could not include patients with multiple fractures in the same limb. This resulted in study groups of 53 and 45 patients' records in the groups before and after the educational session, respectively. Radiation emission from the mini C-arm between both groups were compared. Exposure time with the mini C-arm was longer in patients treated before the educational intervention than in those treated after the intervention (patients with both-bone forearm fractures: mean = 41.2, SD = 24.7, 95% CI, 23.14-59.26 vs mean = 28.9, SD = 14.4, 95% CI, 15.91-41.89, p = 0.066; patients with distal radius fractures: mean = 38.1, SD = 26.1, 95% CI, 25.1-51.1 vs mean = 26.7, SD = 15.8, 95% CI, 16.44-36.96, p = 0.042). Calculated radiation exposure with the mini C-arm was larger in patients treated before the educational intervention than in those treated after the intervention

  5. Microbial hotspots and hot moments in soil

    NASA Astrophysics Data System (ADS)

    Kuzyakov, Yakov; Blagodatskaya, Evgenia

    2015-04-01

    Soils are the most heterogeneous parts of the biosphere, with an extremely high differentiation of properties and processes within nano- to macroscales. The spatial and temporal heterogeneity of input of labile organics by plants creates microbial hotspots over short periods of time - the hot moments. We define microbial hotspots as small soil volumes with much faster process rates and much more intensive interactions compared to the average soil conditions. Such hotspots are found in the rhizosphere, detritusphere, biopores (including drilosphere) and on aggregate surfaces, but hotspots are frequently of mixed origin. Hot moments are short-term events or sequences of events inducing accelerated process rates as compared to the averaged rates. Thus, hotspots and hot moments are defined by dynamic characteristics, i.e. by process rates. For this hotspot concept we extensively reviewed and examined the localization and size of hotspots, spatial distribution and visualization approaches, transport of labile C to and from hotspots, lifetime and process intensities, with a special focus on process rates and microbial activities. The fraction of active microorganisms in hotspots is 2-20 times higher than in the bulk soil, and their specific activities (i.e. respiration, microbial growth, mineralization potential, enzyme activities, RNA/DNA ratio) may also be much higher. The duration of hot moments in the rhizosphere is limited and is controlled by the length of the input of labile organics. It can last a few hours up to a few days. In the detritusphere, however, the duration of hot moments is regulated by the output - by decomposition rates of litter - and lasts for weeks and months. Hot moments induce succession in microbial communities and intense intra- and interspecific competition affecting C use efficiency, microbial growth and turnover. The faster turnover and lower C use efficiency in hotspots counterbalances the high C inputs, leading to the absence of strong

  6. Hotspot evolution and Venusian tectonic style

    NASA Astrophysics Data System (ADS)

    McGill, George E.

    1994-11-01

    Because hotspots represent an important manifestation of heat loss on Venus, their geological evolution is of fundamental importance for any attempt to understand Venusian tectonics. Eistla Regio is an approximately 7500-km-long, moderately elevated region inferred to overlie one or more large mantle upwellings or hotspots. It also contains many shield volcanoes and coronae believed due to the rise of thermal plumes in the mantle. Central Eistla Regio includes two large volcanoes, Sappho and Anala, and several coronae in close proximity. Detailed mapping in this region results in two conclusions of tectonic significance: (1) Sappho and Anala occur near the intersection of two major extensional deformation zones, and (2) the coronae are older than the large volcanoes. Several of the coronae occur as a chain along Guor Linea, one of the major extensional deformation zones. Stratigraphic relationships indicate that the coronae began forming very soon after the emplacement of the widespread regional plains materials. Thus Central Eistla Regio was the site of a swarm of plumes that first formed coronae and then later formed shield volcanoes. The expected result of such a swarm would be thermal thinning of the elastic lithosphere with time. However, model results, geological observations, and gravity data suggest that the change from coronae to shield volcanoes was accompanied by a thickening of the lithosphere with time. This thickening is interpreted to be the result of global cooling of the lithosphere following the most recent episode of near-global resurfacing. The global cooling must have occurred faster than local heating of the lithosphere due to the impingement of thermal plumes.

  7. Hotspot evolution and Venusian tectonic style

    NASA Technical Reports Server (NTRS)

    Mcgill, George E.

    1994-01-01

    Because hotspots represent an important manifestation of heat loss on Venus, their geological evolution is of fundamental importance for any attempt to understand Venusian tectonics. Eistla Regio is an approximately 7500-km-long, moderately elevated region inferred to overlie one or more large mantle upwellings or hotspots. It also contains many shield volcanoes and coronae believed due to the rise of thermal plumes in the mantle. Central Eistla Regio includes two large volcanoes, Sappho and Anala, and several coronae in close proximity. Detailed mapping in this region results in two conclusions of tectonic significance: (1) Sappho and Anala occur near the intersection of two major extensional deformation zones, and (2) the coronae are older than the large volcanoes. Several of the coronae occur as a chain along Guor Linea, one of the major extensional deformation zones. Stratigraphic relationships indicate that the coronae began forming very soon after the emplacement of the widespread regional plains materials. Thus Central Eistla Regio was the site of a swarm of plumes that first formed coronae and then later formed shield volcanoes. The expected result of such a swarm would be thermal thinning of the elastic lithosphere with time. However, model results, geological observations, and gravity data suggest that the change from coronae to shield volcanoes was accompanied by a thickening of the lithosphere with time. This thickening is interpreted to be the result of global cooling of the lithosphere following the most recent episode of near-global resurfacing. The global cooling must have occurred faster than local heating of the lithosphere due to the impingement of thermal plumes.

  8. ENVIRONMENTAL RADIATION MONITORING IN THE CHERNOBYL EXCLUSION ZONE - HISTORY AND RESULTS 25 YEARS AFTER

    SciTech Connect

    Farfan, E.; Jannik, T.

    2011-10-01

    This article describes results of the radiation environmental monitoring performed in the Chernobyl Exclusion Zone (ChEZ) during the period following the 1986 Chernobyl Nuclear Power Plant accident. This article presents a brief overview of five comprehensive reports generated under Contract No. DE-AC09-96SR18500 (Washington Savannah River Company LLC, Subcontract No. AC55559N, SOW No. ON8778) and summarizes characteristics of the ChEZ and its post-accident status and the history of development of the radiation monitoring research in the ChEZ is described. This article addresses characteristics of the radiation monitoring in the ChEZ, its major goals and objectives, and changes of these goals and objectives in the course of time, depending on the tasks associated with the phase of mitigation of the ChNPP accident consequences. The results of the radiation monitoring in the ChEZ during the last 25 years are also provided.

  9. Preliminary Results on Design and Implementation of a Solar Radiation Monitoring System.

    PubMed

    Balan, Mugur C; Damian, Mihai; Jäntschi, Lorentz

    2008-02-19

    The paper presents a solar radiation monitoring system, using two scientificpyranometers and an on-line computer home-made data acquisition system. The firstpyranometer measures the global solar radiation and the other one, which is shaded,measure the diffuse radiation. The values of total and diffuse solar radiation arecontinuously stored into a database on a server. Original software was created for dataacquisition and interrogation of the created system. The server application acquires the datafrom pyranometers and stores it into a database with a baud rate of one record at 50seconds. The client-server application queries the database and provides descriptivestatistics. A web interface allow to any user to define the including criteria and to obtainthe results. In terms of results, the system is able to provide direct, diffuse and totalradiation intensities as time series. Our client-server application computes also derivateheats. The ability of the system to evaluate the local solar energy potential is highlighted.

  10. Environmental radiation monitoring in the Chernobyl exclusion zone--history and results 25 years after.

    PubMed

    Bondarkov, Mikhail D; Oskolkov, Boris Ya; Gaschak, Sergey P; Kireev, Sergey I; Maksimenko, Andrey M; Proskura, Nikolai I; Jannik, G Timothy; Farfán, Eduardo B

    2011-10-01

    This paper describes results of the radiation environmental monitoring performed in the Chernobyl Exclusion Zone (ChEZ) during the period following the 1986 Chernobyl Nuclear Power Plant accident. This article presents a brief overview of five comprehensive reports generated under Contract No. DE-AC09-96SR18500 (Washington Savannah River Company LLC, Subcontract No. AC55559N, SOW No. ON8778) and summarizes characteristics of the ChEZ and its post-accident status. The history of development of the radiation monitoring research in the ChEZ is described also. This paper addresses the characteristics of radiation monitoring in the ChEZ, its major goals and objectives, and changes in these goals and objectives in the course of time, depending on the tasks associated with the phase of mitigation of the ChNPP accident consequences. The results of the radiation monitoring in the ChEZ during the last 25 years are also provided.

  11. The Making of a Productivity Hotspot in the Coastal Ocean

    PubMed Central

    Wingfield, Dana K.; Peckham, S. Hoyt; Foley, David G.; Palacios, Daniel M.; Lavaniegos, Bertha E.; Durazo, Reginaldo; Nichols, Wallace J.; Croll, Donald A.; Bograd, Steven J.

    2011-01-01

    Background Highly productive hotspots in the ocean often occur where complex physical forcing mechanisms lead to aggregation of primary and secondary producers. Understanding how hotspots persist, however, requires combining knowledge of the spatio-temporal linkages between geomorphology, physical forcing, and biological responses with the physiological requirements and movement of top predators. Methodology/Principal Findings Here we integrate remotely sensed oceanography, ship surveys, and satellite telemetry to show how local geomorphology interacts with physical forcing to create a region with locally enhanced upwelling and an adjacent upwelling shadow that promotes retentive circulation, enhanced year-round primary production, and prey aggregation. These conditions provide an area within the upwelling shadow where physiologically optimal water temperatures can be found adjacent to a region of enhanced prey availability, resulting in a foraging hotspot for loggerhead sea turtles (Caretta caretta) off the Baja California peninsula, Mexico. Significance/Conclusions We have identified the set of conditions that lead to a persistent top predator hotspot, which increases our understanding of how highly migratory species exploit productive regions of the ocean. These results will aid in the development of spatially and environmentally explicit management strategies for marine species of conservation concern. PMID:22132156

  12. Detecting Recombination Hotspots from Patterns of Linkage Disequilibrium

    PubMed Central

    Wall, Jeffrey D.; Stevison, Laurie S.

    2016-01-01

    With recent advances in DNA sequencing technologies, it has become increasingly easy to use whole-genome sequencing of unrelated individuals to assay patterns of linkage disequilibrium (LD) across the genome. One type of analysis that is commonly performed is to estimate local recombination rates and identify recombination hotspots from patterns of LD. One method for detecting recombination hotspots, LDhot, has been used in a handful of species to further our understanding of the basic biology of recombination. For the most part, the effectiveness of this method (e.g., power and false positive rate) is unknown. In this study, we run extensive simulations to compare the effectiveness of three different implementations of LDhot. We find large differences in the power and false positive rates of these different approaches, as well as a strong sensitivity to the window size used (with smaller window sizes leading to more accurate estimation of hotspot locations). We also compared our LDhot simulation results with comparable simulation results obtained from a Bayesian maximum-likelihood approach for identifying hotspots. Surprisingly, we found that the latter computationally intensive approach had substantially lower power over the parameter values considered in our simulations. PMID:27226166

  13. Identifying infection hotspots early on.

    PubMed

    Shabha, Ghasson

    2012-04-01

    According to many published studies, 'ducting in ventilation and air-conditioning are largely overlooked and ignored, as they are out of sight and out of mind', despite mounting evidence indicating a higher risk in spreading airborne infections'. So says Ghasson Shabha BSc (Arch) MSc, PhD (Arch), MBIFM, Associate CIBSE, PG Cert Ed, of the Faculty of Technology, Engineering and the Environment (TEE), at the Birmingham School of the Built Environment (BSBE) at Birmingham City University, who adds that CIBSE estimates that fewer than 5% of buildings with air-conditioning systems above 12 kW have been inspected so far. Here he argues that incorporating 3D building information modelling software into existing computer-aided facilities management software systems will enable hospitals' 'infection hotspots' to be far more quickly identified, and subsequently monitored, to prevent future problems.

  14. Cloud recognition from ground-based solar radiation measurements: preliminary results

    NASA Astrophysics Data System (ADS)

    Calbo, Josep; Gonzalez, Josep-Abel

    1998-12-01

    Despite cloud recognition techniques that can routinely identify cloud classes form satellite images, observation of clouds from the ground is still needed to acquire a complete description of cloud climatology. Solar radiation in a given site is one of the meteorological magnitudes that are most affected by cloud cover. Presently, the number of stations where both global and diffuse total solar radiation is measured is growing, due basically to energetic applications of solar radiation. Global and diffuse hourly irradiation, along with some measure of the temporal variability of solar radiation, are used in this paper to describe the sky condition, and to classify it into several cloud types. A classical maximum likelihood method is applied for clustering data. One year of solar radiation data and cloud observations at a site in Catalonia, Spain is used to illustrate the ability of solar radiation measurements to describe cloud types. Preliminary results of the above methodology show that three clusters appear using global and diffuse hourly irradiation only. Fog, stratus, and stratocumulus from the first group. A second group includes altocumulus alone or mixed with other clouds, as well as scattered cumulus congestus. In a third group, we find clear skies, cirrus and scattered cumulus. Especially in this third group, variability of solar radiation within an hour helps to separate different situations.

  15. A multigroup radiation diffusion test problem: Comparison of code results with analytic solution

    SciTech Connect

    Shestakov, A I; Harte, J A; Bolstad, J H; Offner, S R

    2006-12-21

    We consider a 1D, slab-symmetric test problem for the multigroup radiation diffusion and matter energy balance equations. The test simulates diffusion of energy from a hot central region. Opacities vary with the cube of the frequency and radiation emission is given by a Wien spectrum. We compare results from two LLNL codes, Raptor and Lasnex, with tabular data that define the analytic solution.

  16. Biodiversity hotspots house most undiscovered plant species.

    PubMed

    Joppa, Lucas N; Roberts, David L; Myers, Norman; Pimm, Stuart L

    2011-08-09

    For most organisms, the number of described species considerably underestimates how many exist. This is itself a problem and causes secondary complications given present high rates of species extinction. Known numbers of flowering plants form the basis of biodiversity "hotspots"--places where high levels of endemism and habitat loss coincide to produce high extinction rates. How different would conservation priorities be if the catalog were complete? Approximately 15% more species of flowering plant are likely still undiscovered. They are almost certainly rare, and depending on where they live, suffer high risks of extinction from habitat loss and global climate disruption. By using a model that incorporates taxonomic effort over time, regions predicted to contain large numbers of undiscovered species are already conservation priorities. Our results leave global conservation priorities more or less intact, but suggest considerably higher levels of species imperilment than previously acknowledged.

  17. Trans-regulation of mouse meiotic recombination hotspots by Rcr1.

    PubMed

    Parvanov, Emil D; Ng, Siemon H S; Petkov, Petko M; Paigen, Kenneth

    2009-02-17

    Meiotic recombination is required for the orderly segregation of chromosomes during meiosis and for providing genetic diversity among offspring. Among mammals, as well as yeast and higher plants, recombination preferentially occurs at highly delimited chromosomal sites 1-2 kb long known as hotspots. Although considerable progress has been made in understanding the roles various proteins play in carrying out the molecular events of the recombination process, relatively little is understood about the factors controlling the location and relative activity of mammalian recombination hotspots. To search for trans-acting factors controlling the positioning of recombination events, we compared the locations of crossovers arising in an 8-Mb segment of a 100-Mb region of mouse Chromosome 1 (Chr 1) when the longer region was heterozygous C57BL/6J (B6) x CAST/EiJ (CAST) and the remainder of the genome was either similarly heterozygous or entirely homozygous B6. The lack of CAST alleles in the remainder of the genome resulted in profound changes in hotspot activity in both females and males. Recombination activity was lost at several hotspots; new, previously undetected hotspots appeared; and still other hotspots remained unaffected, indicating the presence of distant trans-acting gene(s) whose CAST allele(s) activate or suppress the activity of specific hotspots. Testing the activity of three activated hotspots in sperm samples from individual male progeny of two genetic crosses, we identified a single trans-acting regulator of hotspot activity, designated Rcr1, that is located in a 5.30-Mb interval (11.74-17.04 Mb) on Chr 17. Using an Escherichia coli cloning assay to characterize the molecular products of recombination at two of these hotspots, we found that Rcr1 controls the appearance of both crossover and noncrossover gene conversion events, indicating that it likely controls the sites of the double-strand DNA breaks that initiate the recombination process.

  18. Are hotspots of evolutionary potential adequately protected in southern California?

    USGS Publications Warehouse

    Vandergast, A.G.; Bohonak, A.J.; Hathaway, S.A.; Boys, J.; Fisher, R.N.

    2008-01-01

    Reserves are often designed to protect rare habitats, or "typical" exemplars of ecoregions and geomorphic provinces. This approach focuses on current patterns of organismal and ecosystem-level biodiversity, but typically ignores the evolutionary processes that control the gain and loss of biodiversity at these and other levels (e.g., genetic, ecological). In order to include evolutionary processes in conservation planning efforts, their spatial components must first be identified and mapped. We describe a GIS-based approach for explicitly mapping patterns of genetic divergence and diversity for multiple species (a "multi-species genetic landscape"). Using this approach, we analyzed mitochondrial DNA datasets from 21 vertebrate and invertebrate species in southern California to identify areas with common phylogeographic breaks and high intrapopulation diversity. The result is an evolutionary framework for southern California within which patterns of genetic diversity can be analyzed in the context of historical processes, future evolutionary potential and current reserve design. Our multi-species genetic landscapes pinpoint six hotspots where interpopulation genetic divergence is consistently high, five evolutionary hotspots within which genetic connectivity is high, and three hotspots where intrapopulation genetic diversity is high. These 14 hotspots can be grouped into eight geographic areas, of which five largely are unprotected at this time. The multi-species genetic landscape approach may provide an avenue to readily incorporate measures of evolutionary process into GIS-based systematic conservation assessment and land-use planning.

  19. Performance results of Grumman prototype Space Station Space Erectable Radiator System ground test articles

    NASA Technical Reports Server (NTRS)

    Gisondo, Francine

    1990-01-01

    The paper addresses individual-radiator performance results of the prototype Space Erectable Radiator System (SERS) in both ambient and thermal vacuum environments. The radiator design utilizing a two-phase fluid loop is outlined, along with SERS design requirements, radiator panel hardware, and whiffletree clamp hardware providing a dry-contact interface of the SERS panel with the heat exchanger of the thermal bus. It is observed that throughout integrated thermal-bus tests, SERS panels managed the load demands whether interfacing with twin condensers, in parallel-flow configuration, or with shear-flow condensers, in a cross-flow configuration. It is found that the insulation losses in the integrated and stand-alone test points are approximately 2 to 6 pct. The motorized whiffletree clamp is seen as performing satisfactorily during remote operations as well as maintaining 28,800-lb force throughout the test duration without requiring further adjustments.

  20. HAMLET -Human Model MATROSHKA for Radiation Exposure Determination of Astronauts -Current status and results

    NASA Astrophysics Data System (ADS)

    Reitz, Guenther; Berger, Thomas; Bilski, Pawel; Burmeister, Soenke; Labrenz, Johannes; Hager, Luke; Palfalvi, Jozsef K.; Hajek, Michael; Puchalska, Monika; Sihver, Lembit

    contribute essentially to radiation risk estimations for future interplanetary space exploration by humans, putting them on a solid experimental and theoretical basis. The talk will give an overview of the current status of the MATROSHKA data evaluation and results and comparisons of the first three MTR experimental phases (MTR-1, 2A and 2B). The HAMLET project is funded by the European Commission under the EUs Seventh Frame-work Programme (FP7) under Project Nr: 218817 and coordinated by the German Aerospace Center (DLR) http://www-fp7-hamlet.eu

  1. Deriving Arctic Cloud Microphysics at Barrow, Alaska. Algorithms, Results, and Radiative Closure

    SciTech Connect

    Shupe, Matthew D.; Turner, David D.; Zwink, Alexander; Thieman, Mandana M.; Mlawer, Eli J.; Shippert, Timothy

    2015-07-01

    Cloud phase and microphysical properties control the radiative effects of clouds in the climate system and are therefore crucial to characterize in a variety of conditions and locations. An Arctic-specific, ground-based, multi-sensor cloud retrieval system is described here and applied to two years of observations from Barrow, Alaska. Over these two years, clouds occurred 75% of the time, with cloud ice and liquid each occurring nearly 60% of the time. Liquid water occurred at least 25% of the time even in the winter, and existed up to heights of 8 km. The vertically integrated mass of liquid was typically larger than that of ice. While it is generally difficult to evaluate the overall uncertainty of a comprehensive cloud retrieval system of this type, radiative flux closure analyses were performed where flux calculations using the derived microphysical properties were compared to measurements at the surface and top-of-atmosphere. Radiative closure biases were generally smaller for cloudy scenes relative to clear skies, while the variability of flux closure results was only moderately larger than under clear skies. The best closure at the surface was obtained for liquid-containing clouds. Radiative closure results were compared to those based on a similar, yet simpler, cloud retrieval system. These comparisons demonstrated the importance of accurate cloud phase classification, and specifically the identification of liquid water, for determining radiative fluxes. Enhanced retrievals of liquid water path for thin clouds were also shown to improve radiative flux calculations.

  2. Methodology and software to detect viral integration site hot-spots

    PubMed Central

    2011-01-01

    Background Modern gene therapy methods have limited control over where a therapeutic viral vector inserts into the host genome. Vector integration can activate local gene expression, which can cause cancer if the vector inserts near an oncogene. Viral integration hot-spots or 'common insertion sites' (CIS) are scrutinized to evaluate and predict patient safety. CIS are typically defined by a minimum density of insertions (such as 2-4 within a 30-100 kb region), which unfortunately depends on the total number of observed VIS. This is problematic for comparing hot-spot distributions across data sets and patients, where the VIS numbers may vary. Results We develop two new methods for defining hot-spots that are relatively independent of data set size. Both methods operate on distributions of VIS across consecutive 1 Mb 'bins' of the genome. The first method 'z-threshold' tallies the number of VIS per bin, converts these counts to z-scores, and applies a threshold to define high density bins. The second method 'BCP' applies a Bayesian change-point model to the z-scores to define hot-spots. The novel hot-spot methods are compared with a conventional CIS method using simulated data sets and data sets from five published human studies, including the X-linked ALD (adrenoleukodystrophy), CGD (chronic granulomatous disease) and SCID-X1 (X-linked severe combined immunodeficiency) trials. The BCP analysis of the human X-linked ALD data for two patients separately (774 and 1627 VIS) and combined (2401 VIS) resulted in 5-6 hot-spots covering 0.17-0.251% of the genome and containing 5.56-7.74% of the total VIS. In comparison, the CIS analysis resulted in 12-110 hot-spots covering 0.018-0.246% of the genome and containing 5.81-22.7% of the VIS, corresponding to a greater number of hot-spots as the data set size increased. Our hot-spot methods enable one to evaluate the extent of VIS clustering, and formally compare data sets in terms of hot-spot overlap. Finally, we show that the

  3. Northern Galápagos Province: Hotspot-induced, near-ridge volcanism at Genovesa Island

    NASA Astrophysics Data System (ADS)

    Harpp, Karen S.; Wirth, Karl R.; Korich, Daniel J.

    2002-05-01

    Genovesa Island is a small volcano located between the Galápagos hotspot and the Galápagos spreading center. Several observations suggest that Genovesa may not have originated as a direct product of the Galápagos plume, but instead by anomalous activation of the upper mantle by the plume. Genovesa's lavas exhibit remarkably homogeneous, depleted compositions with no detectable plume contribution; the volcano's trace element contents indicate a deeper origin than either pristine spreading center lavas or most lavas from the Galápagos Archipelago. Genovesa is virtually indistinguishable from the Lamont Seamounts (near the East Pacific Rise) in composition, volume, height, and distance from the ridge; and Genovesa formed close to its current near-ridge location, more recently than previously assumed (age younger than 350 ka). Numerous similar volcanoes populate the northern perimeter of the Galápagos Archipelago. We propose that the northern volcanic province is the result of the serendipitous combination of excess temperatures, weak lithosphere, and regional stresses from interaction between the plume and the ridge, yielding volcanism where none would be observed otherwise. The Galápagos system may define an eruptive process at hotspots, distinct from the Hawaiian model, in which plume-related volcanism can be regionally diffuse, coeval, and compositionally variable. Such a mechanism has profound implications for our understanding of plume-ridge interactions, as well as for island ages and adaptive radiation in the Galápagos.

  4. Threats from Climate Change to Terrestrial Vertebrate Hotspots in Europe

    PubMed Central

    Maiorano, Luigi; Amori, Giovanni; Capula, Massimo; Falcucci, Alessandra; Masi, Monica; Montemaggiori, Alessandro; Pottier, Julien; Psomas, Achilleas; Rondinini, Carlo; Russo, Danilo; Zimmermann, Niklaus E.

    2013-01-01

    We identified hotspots of terrestrial vertebrate species diversity in Europe and adjacent islands. Moreover, we assessed the extent to which by the end of the 21st century such hotspots will be exposed to average monthly temperature and precipitation patterns which can be regarded as extreme if compared to the climate experienced during 1950-2000. In particular, we considered the entire European sub-continent plus Turkey and a total of 1149 species of terrestrial vertebrates. For each species, we developed species-specific expert-based distribution models (validated against field data) which we used to calculate species richness maps for mammals, breeding birds, amphibians, and reptiles. Considering four global circulation model outputs and three emission scenarios, we generated an index of risk of exposure to extreme climates, and we used a bivariate local Moran’s I to identify the areas with a significant association between hotspots of diversity and high risk of exposure to extreme climates. Our results outline that the Mediterranean basin represents both an important hotspot for biodiversity and especially for threatened species for all taxa. In particular, the Iberian and Italian peninsulas host particularly high species richness as measured over all groups, while the eastern Mediterranean basin is particularly rich in amphibians and reptiles; the islands (both Macaronesian and Mediterranean) host the highest richness of threatened species for all taxa occurs. Our results suggest that the main hotspots of biodiversity for terrestrial vertebrates may be extensively influenced by the climate change projected to occur over the coming decades, especially in the Mediterranean bioregion, posing serious concerns for biodiversity conservation. PMID:24066162

  5. Threats from climate change to terrestrial vertebrate hotspots in Europe.

    PubMed

    Maiorano, Luigi; Amori, Giovanni; Capula, Massimo; Falcucci, Alessandra; Masi, Monica; Montemaggiori, Alessandro; Pottier, Julien; Psomas, Achilleas; Rondinini, Carlo; Russo, Danilo; Zimmermann, Niklaus E; Boitani, Luigi; Guisan, Antoine

    2013-01-01

    We identified hotspots of terrestrial vertebrate species diversity in Europe and adjacent islands. Moreover, we assessed the extent to which by the end of the 21(st) century such hotspots will be exposed to average monthly temperature and precipitation patterns which can be regarded as extreme if compared to the climate experienced during 1950-2000. In particular, we considered the entire European sub-continent plus Turkey and a total of 1149 species of terrestrial vertebrates. For each species, we developed species-specific expert-based distribution models (validated against field data) which we used to calculate species richness maps for mammals, breeding birds, amphibians, and reptiles. Considering four global circulation model outputs and three emission scenarios, we generated an index of risk of exposure to extreme climates, and we used a bivariate local Moran's I to identify the areas with a significant association between hotspots of diversity and high risk of exposure to extreme climates. Our results outline that the Mediterranean basin represents both an important hotspot for biodiversity and especially for threatened species for all taxa. In particular, the Iberian and Italian peninsulas host particularly high species richness as measured over all groups, while the eastern Mediterranean basin is particularly rich in amphibians and reptiles; the islands (both Macaronesian and Mediterranean) host the highest richness of threatened species for all taxa occurs. Our results suggest that the main hotspots of biodiversity for terrestrial vertebrates may be extensively influenced by the climate change projected to occur over the coming decades, especially in the Mediterranean bioregion, posing serious concerns for biodiversity conservation.

  6. Revisiting Hotspots and Mantle Plumes: Some Phenomenology

    NASA Astrophysics Data System (ADS)

    King, S. D.; White-Gaynor, A. L.

    2012-12-01

    Sleep (1990) used gravity, topography and heat flow from 37 hotspots to ``constrain the mechanism for swell uplift and to obtain fluxes and excess temperatures of mantle plumes,'' complementing a previous analysis by Davies (1988). We repeat that analysis for the same 37 hotspots using gravity from EGM2008 and topography from ETOPO1 (Amante and Eakins, 2009). EGM2008 is complete to spherical harmonic degree and order 2159, or roughly 20 km spatial resolution (Pavlis et al., 2012). The vertical accuracy of ETOPO1 is on the order of 10 meters. With these new models we hope to improve the uplift and subsidence rates along all 37 hotspot tracks--one of the major limitations the previous work. For example, of the 37 hotspots considered Sleep ranked only 7 with good reliability while 14 were fair and 16 were poor. With this new information we can compare and contrast hotspots with various other groupings of hotspots based on tomographic images of mantle structure (Montelli et al, 2003), primary versus secondary hotspots (Courtillot et al., 2003) or relationship to cratonic boundaries (King, 2008). One encounters some puzzles when attempting to reconcile buoyancy fluxes with other groupings of hotspots and/or observations. For example, Coutillot et al.'s seven primary hotspots include: Afar, Easter, Hawaii, Iceland, Louisville, Réunion, and Tristan. Sleep (1990) categorized the reliability of the buoyancy flux calculated by from Afar, Hawaii, Iceland, and Réunion as good, while Tristan and Easter were fair and Louisville was poor. The calculated buoyancy fluxes from Macdonald and Marqueses (both listed as fair) are twice as large as those from Iceland, Tristan, and Réunion. While we recognize that these observations cannot uniquely constrain the origin of these anomalies, better observations should help test various hypotheses.

  7. NIMS: Hotspots on Io During G2

    NASA Image and Video Library

    1998-03-26

    The Near Infrared Mapping Spectrometer (NIMS) on the Galileo spacecraft imaged Io at high spectral resolution at a range of 439,000 km (275,000 miles) during the G2 encounter on 7 September 1996. This image shows (on the right) Io as seen in the infrared by NIMS. The image on the left shows the same view from Voyager in 1979. This NIMS image can be compared to the NIMS images from the G1 orbit (June 1996) to monitor changes on Io. The NIMS image is at 4.9 microns, showing thermal emissions from the hotspots. The brightness of the pixels is a function of size and temperature. At least 10 hotspots have been identified and can be matched with surface features. An accurate determination of the position of the hotspot in the vicinity of Shamash Patera is pending. Hotspots are seen in the vicinity of Prometheus, Volund and Marduk, all sites of volcanic plume activity during the Galileo encounters, and also of active plumes in 1979. Temperatures and areas have been calculated for the hotspots shown. Temperatures range from 828 K (1031 F) to 210 K (- 81.4 F). The lowest temperature is significantly higher than the Io background (non-hotspot) surface temperature of about 100 K (-279 F). Hotspot areas range from 6.5 square km (2.5 sq miles) to 40,000 sq km (15,400 sq miles). The hottest hotspots have smallest areas, and the cooler hotspots have the largest areas. NIMS is continuing to observe Io to monitor volcanic activity throughout the Galileo mission. http://photojournal.jpl.nasa.gov/catalog/PIA00520

  8. Regional Climate Change Hotspots over Africa

    NASA Astrophysics Data System (ADS)

    Anber, U.; Zakey, A.; Abd El Wahab, M.

    2009-04-01

    Regional Climate Change Index (RCCI), is developed based on regional mean precipitation change, mean surface air temperature change, and change in precipitation and temperature interannual variability. The RCCI is a comparative index designed to identify the most responsive regions to climate change, or Hot- Spots. The RCCI is calculated for Seven land regions over North Africa and Arabian region from the latest set of climate change projections by 14 global climates for the A1B, A2 and B1 IPCC emission scenarios. The concept of climate change can be approaches from the viewpoint of vulnerability or from that of climate response. In the former case a Hot-Spot can be defined as a region for which potential climate change impacts on the environment or different activity sectors can be particularly pronounced. In the other case, a Hot-Spot can be defined as a region whose climate is especially responsive to global change. In particular, the characterization of climate change response-based Hot-Spot can provide key information to identify and investigate climate change Hot-Spots based on results from multi-model ensemble of climate change simulations performed by modeling groups from around the world as contributions to the Fourth Assessment Report of Intergovernmental Panel on Climate Change (IPCC). A Regional Climate Change Index (RCCI) is defined based on four variables: change in regional mean surface air temperature relative to the global average temperature change ( or Regional Warming Amplification Factor, RWAF ), change in mean regional precipitation (P % , of present day value ), change in regional surface air temperature interannual variability (T % ,of present day value), change in regional precipitation interannual variability (P % ,of present day value ). In the definition of the RCCI it is important to include quantities other than mean change because often mean changes are not the only important factors for specific impacts. We thus also include inter

  9. Regional Climate Change Hotspots over Africa

    NASA Astrophysics Data System (ADS)

    Anber, U.

    2009-04-01

    Regional Climate Change Index (RCCI), is developed based on regional mean precipitation change, mean surface air temperature change, and change in precipitation and temperature interannual variability. The RCCI is a comparative index designed to identify the most responsive regions to climate change, or Hot- Spots. The RCCI is calculated for Seven land regions over North Africa and Arabian region from the latest set of climate change projections by 14 global climates for the A1B, A2 and B1 IPCC emission scenarios. The concept of climate change can be approaches from the viewpoint of vulnerability or from that of climate response. In the former case a Hot-Spot can be defined as a region for which potential climate change impacts on the environment or different activity sectors can be particularly pronounced. In the other case, a Hot-Spot can be defined as a region whose climate is especially responsive to global change. In particular, the characterization of climate change response-based Hot-Spot can provide key information to identify and investigate climate change Hot-Spots based on results from multi-model ensemble of climate change simulations performed by modeling groups from around the world as contributions to the Assessment Report of Intergovernmental Panel on Climate Change (IPCC). A Regional Climate Change Index (RCCI) is defined based on four variables: change in regional mean surface air temperature relative to the global average temperature change ( or Regional Warming Amplification Factor, RWAF ), change in mean regional precipitation ( , of present day value ), change in regional surface air temperature interannual variability ( ,of present day value), change in regional precipitation interannual variability ( , of present day value ). In the definition of the RCCI it is important to include quantities other than mean change because often mean changes are not the only important factors for specific impacts. We thus also include inter annual

  10. Hormesis, hotspots and emissions trading.

    PubMed

    Wiener, Jonathan B

    2004-06-01

    Instrument choice--the comparison of technology standards, performance standards, taxes and tradable permits--has been a major topic in environmental law and environmental economics. Most analyses assume that emissions and health effects are positively and linearly related. If they are not, this complicates the instrument choice analysis. This article analyses the effects of a nonlinear dose-response function on instrument choice. In particular, it examines the effects of hormesis (high-dose harm but low-dose benefit) on the choice between fixed performance standards and tradable emissions permits. First, the article distinguishes the effects of hormesis from the effects of local emissions. Hormesis is an attribute of the dose-response or exposure-response relationship. Hotspots are an attribute of the emissions-exposure relationship. Some pollutants may be hormetic and cause local emissions-exposure effects; others may be hormetic without causing local emissions-exposure effects. It is only the local exposure effects of emissions that pose a problem for emissions trading. Secondly, the article shows that the conditions under which emissions trading would perform less well or even perversely under hormesis, depend on how stringent a level of protection is set. Only when the regulatory standard is set at the nadir of the hormetic curve would emissions trading be seriously perverse (assuming other restrictive conditions as well), and such a standard is unlikely. Moreover, the benefits of the overall programme may justify the risk of small perverse effects around this nadir. Thirdly, the article argues that hotspots can be of concern for two distinct reasons, harmfulness and fairness. Lastly, the paper argues that the solution to these problems may not be to abandon market-based incentive instruments and their cost-effectiveness gains, but to improve them further by moving from emissions trading and emissions taxes to risk trading and risk taxes. In short, the article

  11. Outlier Detection on Hotspot Data in Riau Province using OPTICS Algorithm

    NASA Astrophysics Data System (ADS)

    Febriana, N. L.; Sitanggang, I. S.

    2017-03-01

    Hotspot is a point that shows the coordinate of an area with relatively higher temperature than another surrounding area. Hotspot is one of indicators of forest and land fires. An effort in forest and land fires prevention is detecting hotspot occurrences and its outlier. The purpose of this study is to detect outlier occurrences on hotspot data in Riau Province using the density based algorithm namely Ordering Point to Identify the Clustering Structure (OPTICS). The data used are hotspots in Riau Province for the period of 2001 to 2012. In order to find the best clustering results, OPTICS was executed on the parameter Eps of 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.1 and MinPts of 1 to 6. This study found that outliers are commonly occurred in hotspot data in 2007 at the parameter Eps of 0.01 and MinPts of 6. This study identifies 906 outliers in hotspot data in 2007 with SSE of clustering result of 0.0219. Outliers are mostly found in February spreading on several districts including Siak district in Riau Province.

  12. Dissipation and displacement of hotspots in reaction-diffusion models of crime.

    PubMed

    Short, Martin B; Brantingham, P Jeffrey; Bertozzi, Andrea L; Tita, George E

    2010-03-02

    The mechanisms driving the nucleation, spread, and dissipation of crime hotspots are poorly understood. As a consequence, the ability of law enforcement agencies to use mapped crime patterns to design crime prevention strategies is severely hampered. We also lack robust expectations about how different policing interventions should impact crime. Here we present a mathematical framework based on reaction-diffusion partial differential equations for studying the dynamics of crime hotspots. The system of equations is based on empirical evidence for how offenders move and mix with potential victims or targets. Analysis shows that crime hotspots form when the enhanced risk of repeat crimes diffuses locally, but not so far as to bind distant crime together. Crime hotspots may form as either supercritical or subcritical bifurcations, the latter the result of large spikes in crime that override linearly stable, uniform crime distributions. Our mathematical methods show that subcritical crime hotspots may be permanently eradicated with police suppression, whereas supercritical hotspots are displaced following a characteristic spatial pattern. Our results thus provide a mechanistic explanation for recent failures to observe crime displacement in experimental field tests of hotspot policing.

  13. Hotspots trails below Arabia and the Horn of Africa: new insight about the initiation of the Red Sea rift

    NASA Astrophysics Data System (ADS)

    de Gouveia, Sophie Vicente; Besse, Jean; Frizon de Lamotte, Dominique; Greff-Lefftz, Marianne; Gueydan, Frédéric; Lescanne, Marc; Leparmentier, François

    2017-04-01

    The past trajectories followed by three present-day hotspots, Afar, East-Africa and Lake-Victoria were computed using a hotspot reference frame. The tracks are most of time situated under continental crust, which is known to strongly filter surface plume activity. We thus look for surface markers of their ancient existence, such as volcanism, doming, geochemistry and finally by a compilation of heat flow data issued from petroleum wells. Hence, the East-Africa hotspot is episodically warranted up to at least 110 Ma, the Afar one to about 90 Ma and the Lake-Victoria hotspot activity appears more recent and is attested until the Cenozoic. According to the hotspot trajectories, two important issues are addressed. Firstly, the Afar hotspot was situated 1000 km on the north-east of the Ethiopian-Yemen traps at 32 Ma, too far to be responsible for it. The trigger was most probably the East-Africa hotspot situated at the right location at that time. Secondly, we address the question of the Arabian Plate formation as the result of the coeval opening of both the Gulf of Aden and the Red Sea in a context characterized by extensional forces linked to the Neo-Tethys slab-pull: (1) the Gulf of Aden overlaps on inherited Mesozoic extensional basin between two weak zones, the Carlsberg ridge's end and a hotspot heated area; while (2) the Red Sea develops on the previous hotspot track location suggesting a causal relationship between a thermal weakening of the lithosphere and the rift initiation. To test this idea, we performed a numerical simulation in order to describe the lithosphere strength evolution when exposed to a hotspot heating combined with tectonic forces along the East-Africa hotspot track from 110 Ma until the beginning of the rifting at early Oligocene time. Preliminary results suggest that the Red Sea rift was compelled to evolve in a specific area pre-weakened by a hotspot impact.

  14. Ultraconfined Plasmonic Hotspots Inside Graphene Nanobubbles.

    PubMed

    Fei, Z; Foley, J J; Gannett, W; Liu, M K; Dai, S; Ni, G X; Zettl, A; Fogler, M M; Wiederrecht, G P; Gray, S K; Basov, D N

    2016-12-14

    We report on a nanoinfrared (IR) imaging study of ultraconfined plasmonic hotspots inside graphene nanobubbles formed in graphene/hexagonal boron nitride (hBN) heterostructures. The volume of these plasmonic hotspots is more than one-million-times smaller than what could be achieved by free-space IR photons, and their real-space distributions are controlled by the sizes and shapes of the nanobubbles. Theoretical analysis indicates that the observed plasmonic hotspots are formed due to a significant increase of the local plasmon wavelength in the nanobubble regions. Such an increase is attributed to the high sensitivity of graphene plasmons to its dielectric environment. Our work presents a novel scheme for plasmonic hotspot formation and sheds light on future applications of graphene nanobubbles for plasmon-enhanced IR spectroscopy.

  15. Preliminary Results on Design and Implementation of a Solar Radiation Monitoring System

    PubMed Central

    Balan, Mugur C.; Damian, Mihai; Jäntschi, Lorentz

    2008-01-01

    The paper presents a solar radiation monitoring system, using two scientific pyranometers and an on-line computer home-made data acquisition system. The first pyranometer measures the global solar radiation and the other one, which is shaded, measure the diffuse radiation. The values of total and diffuse solar radiation are continuously stored into a database on a server. Original software was created for data acquisition and interrogation of the created system. The server application acquires the data from pyranometers and stores it into a database with a baud rate of one record at 50 seconds. The client-server application queries the database and provides descriptive statistics. A web interface allow to any user to define the including criteria and to obtain the results. In terms of results, the system is able to provide direct, diffuse and total radiation intensities as time series. Our client-server application computes also derivate heats. The ability of the system to evaluate the local solar energy potential is highlighted. PMID:27879746

  16. Hotspots Detection from Trajectory Data Based on Spatiotemporal Data Field Clustering

    NASA Astrophysics Data System (ADS)

    Qin, K.; Zhou, Q.; Wu, T.; Xu, Y. Q.

    2017-09-01

    City hotspots refer to the areas where residents visit frequently, and large traffic flow exist, which reflect the people travel patterns and distribution of urban function area. Taxi trajectory data contain abundant information about urban functions and citizen activities, and extracting interesting city hotspots from them can be of importance in urban planning, traffic command, public travel services etc. To detect city hotspots and discover a variety of changing patterns among them, we introduce a data field-based cluster analysis technique to the pick-up and drop-off points of taxi trajectory data and improve the method by introducing the time weight, which has been normalized to estimate the potential value in data field. Thus, in the light of the new potential function in data field, short distance and short time difference play a powerful role. So the region full of trajectory points, which is regarded as hotspots area, has a higher potential value, while the region with thin trajectory points has a lower potential value. The taxi trajectory data of Wuhan city in China on May 1, 6 and 9, 2015, are taken as the experimental data. From the result, we find the sustaining hotspots area and inconstant hotspots area in Wuhan city based on the spatiotemporal data field method. Further study will focus on optimizing parameter and the interaction among hotspots area.

  17. Genetic assignment of large seizures of elephant ivory reveals Africa’s major poaching hotspots

    PubMed Central

    Wasser, S. K.; Brown, L.; Mailand, C.; Mondol, S.; Clark, W.; Laurie, C.; Weir, B. S.

    2017-01-01

    Poaching of elephants is now occurring at rates that threaten African populations with extinction. Identifying the number and location of Africa’s major poaching hotspots may assist efforts to end poaching and facilitate recovery of elephant populations. We genetically assign origin to 28 large ivory seizures (≥0.5 metric tons) made between 1996 and 2014, also testing assignment accuracy. Results suggest that the major poaching hotspots in Africa may be currently concentrated in as few as two areas. Increasing law enforcement in these two hotspots could help curtail future elephant losses across Africa and disrupt this organized transnational crime. PMID:26089357

  18. CONSERVATION. Genetic assignment of large seizures of elephant ivory reveals Africa's major poaching hotspots.

    PubMed

    Wasser, S K; Brown, L; Mailand, C; Mondol, S; Clark, W; Laurie, C; Weir, B S

    2015-07-03

    Poaching of elephants is now occurring at rates that threaten African populations with extinction. Identifying the number and location of Africa's major poaching hotspots may assist efforts to end poaching and facilitate recovery of elephant populations. We genetically assign origin to 28 large ivory seizures (≥0.5 metric tons) made between 1996 and 2014, also testing assignment accuracy. Results suggest that the major poaching hotspots in Africa may be currently concentrated in as few as two areas. Increasing law enforcement in these two hotspots could help curtail future elephant losses across Africa and disrupt this organized transnational crime. Copyright © 2015, American Association for the Advancement of Science.

  19. North Atlantic Aerosol Properties and Direct Radiative Effects: Key Results from TARFOX and ACE-2

    NASA Technical Reports Server (NTRS)

    Russell, P. B.; Livingston, J. M.; Schmid, B.; Bergstrom, R. A.; Hignett, P.; Hobbs, P. V.; Durkee, P. A.; Condon, Estelle (Technical Monitor)

    1998-01-01

    Aerosol effects on atmospheric radiative fluxes provide a forcing function that can change the climate in potentially significant ways. This aerosol radiative Forcing is a major source of uncertainty in understanding the observed climate change of the past century and in predicting, future climate. To help reduce this uncertainty, the International Global Atmospheric Chemistry Project (IGAC) has endorsed a series of multiplatform aerosol field campaigns. The Tropospheric Aerosol Radiative Forcing Observational Experiment (TARFOX) and the second Aerosol Characterization Experiment (ACE-2) were the first IGAC campaigns to address the impact of anthropogenic aerosols. Both TARFOX and ACE-2 gathered extensive data sets on aerosol properties and radiative effects. TARFOX focused on the urban-industrial haze plume flowing from the eastern United States over the western Atlantic Ocean, whereas ACE-2 studied aerosols carried over the eastern Atlantic from both European urban/industrial and African mineral sources. These aerosols often have a marked influence on the top-of-atmosphere radiances measured by satellites, as illustrated in Figure 1. Shown there are contours of aerosol optical depth derived from radiances measured by the AVHRR sensor on the NOAA-11 satellite. The contours readily show that aerosols originating in North America, Europe, and Africa impact the radiative properties of air over the North Atlantic. However, the accurate derivation of flux chances, or radiative forcing, from the satellite-measured radiances or 'etrieved optical depths remains a difficult challenge. In this paper we summarize key Initial results from TARFOX and, to a lesser extent ACE-2, with a focus on those results that allow an improved assessment of the flux changes caused by North Atlantic aerosols at middle and high latitudes.

  20. North Atlantic Aerosol Properties and Direct Radiative Effects: Key Results from TARFOX and ACE-2

    NASA Technical Reports Server (NTRS)

    Russell, P. B.; Livingston, J. M.; Schmid, B.; Bergstrom, Robert A.; Hignett, P.; Hobbs, P. V.; Durkee, P. A.

    2000-01-01

    Aerosol effects on atmospheric radiative fluxes provide a forcing function that can change the climate In potentially significant ways. This aerosol radiative forcing is a major source of uncertainty in understanding the observed climate change of the past century and in predicting future climate. To help reduce this uncertainty, the International Global Atmospheric Chemistry Project (IGAC) has endorsed a series of multiplatform aerosol field campaigns. The Tropospheric Aerosol Radiative Forcing Observational Experiment (TARFOX) and the second Aerosol Characterization Experiment (ACE-2) were the first IGAC campaigns to address the impact of anthropogenic aerosols, Both TARFOX and ACE-2 gathered extensive data sets on aerosol properties and radiative effects, TARFOX focused on the urban-industrial haze plume flowing from the eastern United States over the western Atlantic Ocean, whereas ACE-2 studied aerosols carried over the eastern Atlantic from both European urban/industrial and African mineral sources. These aerosols often have a marked influence on the top-of-atmosphere radiances measured by satellites. Shown there are contours of aerosol optical depth derived from radiances measured by the AVHRR sensor on the NOAA-11 satellite. The contours readily show that aerosols originating in North America, Europe, and Africa impact the radiative properties of air over the North Atlantic. However, the accurate derivation of flux changes, or radiative forcing, from the satellite measured radiances or retrieved optical depths remains a difficult challenge. In this paper we summarize key initial results from TARFOX and, to a lesser extent, ACE-2, with a focus on those results that allow an improved assessment of the flux changes caused by North Atlantic aerosols at middle latitudes.

  1. Optical Verification of Microbubble Response to Acoustic Radiation Force in Large Vessels with In Vivo Results

    PubMed Central

    Wang, Shiying; Wang, Claudia Y.; Unnikrishnan, Sunil; Klibanov, Alexander L.; Hossack, John A.; Mauldin, F. William

    2015-01-01

    Objectives To optically verify the dynamic behaviors of adherent microbubbles in large blood vessel environments in response to a new ultrasound technique using modulated acoustic radiation force. Materials and Methods Polydimethylsiloxane (PDMS) flow channels coated with streptavidin were used in targeted groups to mimic large blood vessels. The custom modulated acoustic radiation force beam sequence was programmed on a Verasonics research scanner. In vitro experiments were performed by injecting a biotinylated lipid-perfluorobutane microbubble dispersion through flow channels. The dynamic response of adherent microbubbles was detected acoustically and simultaneously visualized using a video camera connected to a microscope. In vivo verification was performed in a large abdominal blood vessel of a murine model for inflammation with injection of biotinylated microbubbles conjugated with P-selectin antibody. Results Aggregates of adherent microbubbles were observed optically under the influence of acoustic radiation force. Large microbubble aggregates were observed solely in control groups without targeted adhesion. Additionally, the dispersion of microbubble aggregates were demonstrated to lead to a transient acoustic signal enhancement in control groups (a new phenomenon we refer to as “control peak”). In agreement with in vitro results, the “control peak” phenomenon was observed in vivo in a murine model. Conclusions This study provides the first optical observation of microbubble binding dynamics in large blood vessel environments with application of a modulated acoustic radiation force beam sequence. With targeted adhesion, secondary radiation forces were unable to produce large aggregates of adherent microbubbles. Additionally, the new phenomenon called “control peak” was observed both in vitro and in vivo in a murine model for the first time. The findings in this study provide us with a better understanding of microbubble behaviors in large blood

  2. North Atlantic Aerosol Properties and Direct Radiative Effects: Key Results from TARFOX and ACE-2

    NASA Technical Reports Server (NTRS)

    Russell, P. B.; Livingston, J. M.; Schmid, B.; Bergstrom, Robert A.; Hignett, P.; Hobbs, P. V.; Durkee, P. A.

    2000-01-01

    Aerosol effects on atmospheric radiative fluxes provide a forcing function that can change the climate In potentially significant ways. This aerosol radiative forcing is a major source of uncertainty in understanding the observed climate change of the past century and in predicting future climate. To help reduce this uncertainty, the International Global Atmospheric Chemistry Project (IGAC) has endorsed a series of multiplatform aerosol field campaigns. The Tropospheric Aerosol Radiative Forcing Observational Experiment (TARFOX) and the second Aerosol Characterization Experiment (ACE-2) were the first IGAC campaigns to address the impact of anthropogenic aerosols, Both TARFOX and ACE-2 gathered extensive data sets on aerosol properties and radiative effects, TARFOX focused on the urban-industrial haze plume flowing from the eastern United States over the western Atlantic Ocean, whereas ACE-2 studied aerosols carried over the eastern Atlantic from both European urban/industrial and African mineral sources. These aerosols often have a marked influence on the top-of-atmosphere radiances measured by satellites. Shown there are contours of aerosol optical depth derived from radiances measured by the AVHRR sensor on the NOAA-11 satellite. The contours readily show that aerosols originating in North America, Europe, and Africa impact the radiative properties of air over the North Atlantic. However, the accurate derivation of flux changes, or radiative forcing, from the satellite measured radiances or retrieved optical depths remains a difficult challenge. In this paper we summarize key initial results from TARFOX and, to a lesser extent, ACE-2, with a focus on those results that allow an improved assessment of the flux changes caused by North Atlantic aerosols at middle latitudes.

  3. What do Patients Want From Their Radiation Oncologist? Initial Results From a Prospective Trial

    SciTech Connect

    Bhatnagar, Ajay K.; Heron, Dwight E.; Flickinger, John C.

    2007-12-01

    Purpose: To assess patients' initial physician preferences using a newly developed instrument. Methods and Materials: A total of 182 patients with a primary diagnosis of prostate, breast, or lung cancer referred for consultation to University of Pittsburgh Cancer Institute Department of Radiation Oncology enrolled in our institutional review board-approved protocol. All patients completed patient preference instrument surveys before meeting their radiation oncologist. Survey responses to 10 statements were categorized into three groups (agree, neutral, or disagree), and the association of survey responses by cancer site was tested with chi-squared tests. Results: Ninety-nine percent of all patients preferred to be addressed by their first name in encounters with their radiation oncologist. There were significant associations of Item 3 (hand holding) with gender (p = 0.039) and education (p = 0.028). The responses to Item 5, a statement that patients would feel uncomfortable if the radiation oncologist offered to hug them at the end of treatment, was significantly associated with disease site (p < 0.0001). Further analysis was performed for Item 5 and revealed that the male lung cancer patients had a much higher rate of disagreement with Item 5 compared with prostate cancer patients (37% vs. 18%). Conclusions: Results of this study may afford greater insight and foster better understanding of what patients want from their radiation oncologist. For breast, lung, and prostate cancer patients, initial preferences for their radiation oncologist are generally similar, according to this tool. However, there are important difference among cancer sites (and gender) regarding physical contact at the end of treatment.

  4. Results of the 2004 Association of Residents in Radiation Oncology (ARRO) Survey

    SciTech Connect

    Patel, Shilpen . E-mail: spatel@umm.edu; Jagsi, Reshma; Wilson, John; Frank, Steven; Thakkar, Vipul V.; Hansen, Eric K.

    2006-11-15

    Purpose: The aim of this study was to document adequacy of training, career plans after residency, use of the in-service examination, and motivation for choice of radiation oncology as a specialty. Methods and Materials: In 2004, the Association of Residents in Radiation Oncology (ARRO) conducted a nationwide survey of all radiation oncology residents in the United States. Results: The survey was returned by 297 residents (response rate, 54%). Of the respondents, 29% were female and 71% male. The most popular career choice was joining an established private practice (38%), followed by a permanent academic career (29%). Residents for whom a permanent academic career was not their first choice were asked whether improvements in certain areas would have led them to be more likely to pursue an academic career. The most commonly chosen factors that would have had a strong or moderate influence included higher salary (81%), choice of geographic location (76%), faculty encouragement (68%), and less time commitment (68%). Of respondents in the first 3 years of training, 78% believed that they had received adequate training to proceed to the next level of training. Of those in their fourth year of training, 75% believed that they had received adequate training to enter practice. Conclusions: Multiple factors affect the educational environment of physicians in training. Data describing concerns unique to resident physicians in radiation oncology are limited. The current survey was designed to explore a variety of issues confronting radiation oncology residents. Training programs and the Residency Review Committee should consider these results when developing new policies to improve the educational experiences of residents in radiation oncology.

  5. Widespread Synchronous Volcanism Reveals a Broad Galapagos Hotspot Melting Anomaly

    NASA Astrophysics Data System (ADS)

    O'Connor, J. M.; Stoffers, P.; Wijbrans, J. R.; Worthington, T. J.

    2004-12-01

    volcanism created by the broad Galapagos melting anomaly have been fragmented between the Cocos and Nazca plates. However, interplay between the broad Galapagos melting anomaly and the Cocos-Nazca spreading center is a second-order process compared to a fundamental underlying mantle process responsible for a broad Galapagos hotspot melting anomaly exhibiting long-lived characteristics (size, time-progression, episodicity) which, on a first-order, are independent of local tectonics and lithospheric architecture. Evidence for a broad Galapagos hotspot melting anomaly and the possibility of detecting long-lived underlying mantle processes has implications for how oceanic hotspot volcanism is sampled for purposes of rigorously testing the mantle plume paradigm. A major question posed by our results is whether individual Pacific seamount chains are in fact the product of tectonic plate drift over narrow hotspots? If not, then inferring the existence and behavior of a mantle plume on the basis of age progression of volcanism produced by a narrow seamount chain could well prove to be misleading. Thus, although great leaps are being made in the theory and numerical modeling - often on a global scale - of hypothesized deep plumes, significantly more high-quality age and geochemical data are needed for oceanic hotspot volcanism that gave birth to the mantle plume hypothesis in the first place.

  6. Denitrification Hotspots: Hydrology and Biogeochemistry

    NASA Astrophysics Data System (ADS)

    Molodovskaya, M.; Singurindy, O.; Faulkner, J. W.; Zhang, W.; Richards, B. K.; Anderson, T. R.; Geohring, L. D.; Steenhuis, T. S.; Walter, M.

    2007-12-01

    Nitrogen (N) is a critical pollutant in many northeastern US watersheds and globally. Many forms of N, especially NO3, pose serious threats to coastal marine ecosystems. Agricultural land that receives fertilizers or animal manures is a principal source of anthropogenic N loading to the environment. The most effective mechanism to reduce N in streams is probably microbial denitrification, i.e., the transformation of nitrate into gaseous N2 or, in some cases, smaller amounts of N2O. Unfortunately, N2O is a greenhouse gas that may contribute to global warming. Currently, magnitudes of denitrification rates at landscape scales are "tentative" at best, largely based on watershed-scale budgets in which denitrification was estimated by difference. Denitrification and N2O net production strongly depend on both natural (temperature, soil moisture, microbial activity, soil organic matter) and anthropogenic (nitrogen fertilization, crop type, tillage) parameters. Denitrification occurs primarily under anaerobic conditions by heterotrophic microbes and is expected to be vigorous in wet soils high in organic carbon. There is good evidence that these conditions correlate strongly with hydrological sensitivity or high propensity for saturated conditions, thus by juxtaposing hydrology and biogeochemistry we can elucidate the distribution of denitrification hotspots across the landscape. Upon this hydrologic-biogeochemical framework we can ultimately develop BMPs to meet the program research priorities to improve water resource protection and promote sustainable agricultural systems that minimize environmental impact. The Cornell Soil and Water and Ecohydrology Research Groups have engaged in a variety of projects to elucidate the primary controls or quantify denitrification rates for different ecohydrological conditions including those that have been specifically designed to reduce N loading to streams. This presentation highlights recent findings of rates, controls, and spatio

  7. Radiation-Induced Salivary Gland Dysfunction Results From p53-Dependent Apoptosis

    SciTech Connect

    Avila, Jennifer L.; Grundmann, Oliver; Burd, Randy; Limesand, Kirsten H.

    2009-02-01

    Purpose: Radiotherapy for head-and-neck cancer causes adverse secondary side effects in the salivary glands and results in diminished quality of life for the patient. A previous in vivo study in parotid salivary glands demonstrated that targeted head-and-neck irradiation resulted in marked increases in phosphorylated p53 (serine{sup 18}) and apoptosis, which was suppressed in transgenic mice expressing a constitutively active mutant of Akt1 (myr-Akt1). Methods and Materials: Transgenic and knockout mouse models were exposed to irradiation, and p53-mediated transcription, apoptosis, and salivary gland dysfunction were analyzed. Results: The proapoptotic p53 target genes PUMA and Bax were induced in parotid salivary glands of mice at early time points after therapeutic radiation. This dose-dependent induction requires expression of p53 because no radiation-induced expression of PUMA and Bax was observed in p53-/- mice. Radiation also induced apoptosis in the parotid gland in a dose-dependent manner, which was p53 dependent. Furthermore, expression of p53 was required for the acute and chronic loss of salivary function after irradiation. In contrast, apoptosis was not induced in p53-/- mice, and their salivary function was preserved after radiation exposure. Conclusions: Apoptosis in the salivary glands after therapeutic head-and-neck irradiation is mediated by p53 and corresponds to salivary gland dysfunction in vivo.

  8. Long-lived but Discontinuous Hotspot Volcanism of the South Pacific Mantle

    NASA Astrophysics Data System (ADS)

    Koppers, A.; Staudigel, H.; Wijbrans, J.; Pringle, M.

    2001-12-01

    with their own distinct isotope signature and only intermittently active over geological time. We pose that their resulting long-lived but discontinuous volcanism should be considered another end-member type of hotspot volcanism - as opposed to the strong and continuous Hawaiian-type hotspots.

  9. Bevacizumab, Oxaliplatin, and Capecitabine With Radiation Therapy in Rectal Cancer: Phase I Trial Results

    SciTech Connect

    Czito, Brian G. . E-mail: czito001@mc.duke.edu; Bendell, Johanna C.; Willett, Christopher G.; Morse, Michael A.; Blobe, Gerard C.; Tyler, Douglas S.; Thomas, John; Ludwig, Kirk A.; Mantyh, Christopher R.; Ashton, Jill; Yu Daohai; Hurwitz, Herbert I.

    2007-06-01

    Purpose: The overexpression of vascular endothelial growth factor (VEGF) is associated with poor outcomes in colorectal cancer patients. Bevacizumab, a VEGF inhibitor, enhances the effects of chemotherapy and radiation therapy on tumor cytotoxicity in preclinical models, including colorectal cancer. A Phase I trial was undertaken to evaluate the combination of bevacizumab, capecitabine, oxaliplatin, and radiation therapy in patients with rectal cancer. Methods and Materials: Patients with pathologically confirmed adenocarcinoma of the rectum were eligible. Pretreatment staging included computerized tomography, endoscopic ultrasound, and surgical evaluation. Patients received 50.4 Gy of external beam radiation therapy (EBRT) to the tumor in 28 fractions. Capecitabine, oxaliplatin, and bevacizumab were administered concurrently with radiation therapy. After EBRT completion, patients were restaged and evaluated for surgery. Primary endpoints included the determination of dose-limiting toxicity and a recommended Phase II dose, non dose-limiting toxicity, and preliminary radiographic and pathologic response rates. Results: Eleven patients were enrolled. All were evaluable for toxicity and efficacy. Dose level 2 was associated with unacceptable toxicity (primarily diarrhea). Dose level 1 had an acceptable toxicity profile. The recommended Phase II dose in our study was bevacizumab 15 mg/kg Day 1 + 10 mg/kg Days 8 and 22, oxaliplatin 50 mg/m{sup 2} weekly, and capecitabine 625 mg/m{sup 2} bid during radiation days. Six patients had clinical responses. Two patients had a pathologic complete response, and 3 had microscopic disease only. One patient experienced a postoperative abscess, one a syncopal episode during adjuvant chemotherapy, and one a subclinical myocardial infarction during adjuvant chemotherapy. Conclusions: The combination of bevacizumab, capecitabine, oxaliplatin, and radiation therapy in rectal cancer was tolerable, with encouraging response rates. Further

  10. Results of genetic examination of populations living in radiative polluted regions of Sibera

    SciTech Connect

    Ilyinskikh, N.N.; Ilyinskikh, E.N.; Ilyinskikh, I.N.

    1997-10-01

    More than twenty thousand inhabitants of Siberia and the Urals, subjected to a radiating effect a result of explosions on the Semipalatinsk nuclear range and after failures at the enterprises making elements of nuclear weapons (Tomsk-7- a Siberian chemical combine and Cheliabinsk - the industrial association {open_quotes}Majak{close_quotes}) were investigated by genetic methods (chromosomatic, micronuclear and DNA-repair tests). Scientists from the Netherlands (A.T. Natarajam), Russia (I.Suskov and N.Ilyinskikh) have established, that high accumulated doses of radiation are observed in people, living near to Siberian chemical combine (Tomsk-7). It has been established, that the effective equivalent dose of radiation much exceeded the level which the person can receive for life from natural sources of radiation in more than 50% of the cases. In some people this dose was much higher 1 Gy. A high level of cells with cytogenetic breaks were predominantly observed in the people born in periods when there were radiating failures or {open_quotes}dirty{close_quotes} nuclear tests on Semipalatinsk nuclear range. We assume that the long preservation in the body of the person of genetic instability is stipulated by occurrence of genetically defective cells in the person in the prenatal period of life. It has been established, that in the long term effects of radiation, the following changes are observed in the people: the number erythrocytes with micronuclei. T-lymphocytes with micronuclei and chromosomic breaks is increased, thus the activity excessive DNA-repair is reduced. Ring and dicentric chromosomes prevailed among other types of cytogenetic breaks in lymphocytes. Genetic instability was accompanied by essential haematologic and immunologic changes. Reduced ability of lumphoid of cells to product interferon and DNA-repair was observed in the people with high cytogenetic instability.

  11. Overview of the Liulin type instruments for space radiation measurement and their scientific results

    NASA Astrophysics Data System (ADS)

    Dachev, T. P.; Semkova, J. V.; Tomov, B. T.; Matviichuk, Yu. N.; Dimitrov, P. G.; Koleva, R. T.; Malchev, St.; Bankov, N. G.; Shurshakov, V. A.; Benghin, V. V.; Yarmanova, E. N.; Ivanova, O. A.; Häder, D.-P.; Lebert, M.; Schuster, M. T.; Reitz, G.; Horneck, G.; Uchihori, Y.; Kitamura, H.; Ploc, O.; Cubancak, J.; Nikolaev, I.

    2015-01-01

    Ionizing radiation is recognized to be one of the main health concerns for humans in the space radiation environment. Estimation of space radiation effects on health requires the accurate knowledge of the accumulated absorbed dose, which depends on the global space radiation distribution, solar cycle and local shielding generated by the 3D mass distribution of the space vehicle. This paper presents an overview of the spectrometer-dosimeters of the Liulin type, which were developed in the late 1980s and have been in use since then. Two major measurement systems have been developed by our team. The first one is based on one silicon detector and is known as a Liulin-type deposited energy spectrometer (DES) (Dachev et al., 2002, 2003), while the second one is a dosimetric telescope (DT) with two or three silicon detectors. The Liulin-type instruments were calibrated using a number of radioactive sources and particle accelerators. The main results of the calibrations are presented in the paper. In the last section of the paper some of the most significant scientific results obtained in space and on aircraft, balloon and rocket flights since 1989 are presented.

  12. Overview of the Liulin type instruments for space radiation measurement and their scientific results.

    PubMed

    Dachev, T P; Semkova, J V; Tomov, B T; Matviichuk, Yu N; Dimitrov, P G; Koleva, R T; Malchev, St; Bankov, N G; Shurshakov, V A; Benghin, V V; Yarmanova, E N; Ivanova, O A; Häder, D-P; Lebert, M; Schuster, M T; Reitz, G; Horneck, G; Uchihori, Y; Kitamura, H; Ploc, O; Cubancak, J; Nikolaev, I

    2015-01-01

    Ionizing radiation is recognized to be one of the main health concerns for humans in the space radiation environment. Estimation of space radiation effects on health requires the accurate knowledge of the accumulated absorbed dose, which depends on the global space radiation distribution, solar cycle and local shielding generated by the 3D mass distribution of the space vehicle. This paper presents an overview of the spectrometer-dosimeters of the Liulin type, which were developed in the late 1980s and have been in use since then. Two major measurement systems have been developed by our team. The first one is based on one silicon detector and is known as a Liulin-type deposited energy spectrometer (DES) (Dachev et al., 2002, 2003), while the second one is a dosimetric telescope (DT) with two or three silicon detectors. The Liulin-type instruments were calibrated using a number of radioactive sources and particle accelerators. The main results of the calibrations are presented in the paper. In the last section of the paper some of the most significant scientific results obtained in space and on aircraft, balloon and rocket flights since 1989 are presented.

  13. Thermal Hotspots in CPU Die and It's Future Architecture

    NASA Astrophysics Data System (ADS)

    Wang, Jian; Hu, Fu-Yuan

    Owing to the increasing core frequency and chip integration and the limited die dimension, the power densities in CPU chip have been increasing fastly. The high temperature on chip resulted by power densities threats the processor's performance and chip's reliability. This paper analyzed the thermal hotspots in die and their properties. A new architecture of function units in die - - hot units distributed architecture is suggested to cope with the problems of high power densities for future processor chip.

  14. A micro-epidemiological analysis of febrile malaria in Coastal Kenya showing hotspots within hotspots

    PubMed Central

    Bejon, Philip; Williams, Thomas N; Nyundo, Christopher; Hay, Simon I; Benz, David; Gething, Peter W; Otiende, Mark; Peshu, Judy; Bashraheil, Mahfudh; Greenhouse, Bryan; Bousema, Teun; Bauni, Evasius; Marsh, Kevin; Smith, David L; Borrmann, Steffen

    2014-01-01

    Malaria transmission is spatially heterogeneous. This reduces the efficacy of control strategies, but focusing control strategies on clusters or ‘hotspots’ of transmission may be highly effective. Among 1500 homesteads in coastal Kenya we calculated (a) the fraction of febrile children with positive malaria smears per homestead, and (b) the mean age of children with malaria per homestead. These two measures were inversely correlated, indicating that children in homesteads at higher transmission acquire immunity more rapidly. This inverse correlation increased gradually with increasing spatial scale of analysis, and hotspots of febrile malaria were identified at every scale. We found hotspots within hotspots, down to the level of an individual homestead. Febrile malaria hotspots were temporally unstable, but 4 km radius hotspots could be targeted for 1 month following 1 month periods of surveillance. DOI: http://dx.doi.org/10.7554/eLife.02130.001 PMID:24843017

  15. Results of conservative surgery and radiation for mammographically detected ductal carcinoma in situ (DCIS).

    PubMed

    Fowble, B; Hanlon, A L; Fein, D A; Hoffman, J P; Sigurdson, E R; Patchefsky, A; Kessler, H

    1997-07-15

    The role of conservative surgery and radiation for mammographically detected ductal carcinoma in situ (DCIS) is controversial. In particular, there is little data for outcome with radiation in a group of patients comparable to those treated with local excision and surveillance (mammographic calcifications < or = 2.5 cm, negative resection margins, negative postbiopsy mammogram). This study reports outcome of conservative surgery and radiation for mammographically detected DCIS with an emphasis on results in patients considered candidates for excision alone. From 1983 to 1992, 110 women with mammographically detected DCIS (77% calcifications +/- mass) and no prior history of breast cancer underwent needle localization and biopsy with (55%) or without a reexcision and radiation. Final margins of resection were negative in 62%, positive 7%, close 11%, and unknown 20%. The median patient age was 56 years. The most common histologic subtype was comedo (54%), followed by cribriform (22%). The median pathologic tumor size was 8 mm (range 2 mm to 5 cm). Forty-seven percent of patients with calcifications only had a negative postbiopsy mammogram prior to radiation. Radiation consisted of treatment to the entire breast (median 50.00 Gy) and a boost to the primary site (97%) for a median total dose of 60.40 Gy. With a median follow-up of 5.3 years, three patients developed a recurrence in the treated breast. The median interval to recurrence was 8.8 years and all were invasive cancers. Two (67%) occurred outside the initial quadrant. The 5- and 10-year actuarial rates of recurrence were 1 and 15%. Cause-specific survival was 100% at 5 and 10 years. Contralateral breast cancer developed in two patients. There were too few failures for statistical significance to be achieved with any of the following factors: patient age, family history, race, mammographic findings, location primary, pathologic size, histologic subtype, reexcision, or final margin status. However, young age

  16. Regional differences in recombination hotspots between two chicken populations

    PubMed Central

    2010-01-01

    Background Although several genetic linkage maps of the chicken genome have been published, the resolution of these maps is limited and does not allow the precise identification of recombination hotspots. The availability of more than 3.2 million SNPs in the chicken genome and the recent advances in high throughput genotyping techniques enabled us to increase marker density for the construction of a high-resolution linkage map of the chicken genome. This high-resolution linkage map allowed us to study recombination hotspots across the genome between two chicken populations: a purebred broiler line and a broiler × broiler cross. In total, 1,619 animals from the two different broiler populations were genotyped with 17,790 SNPs. Results The resulting linkage map comprises 13,340 SNPs. Although 360 polymorphic SNPs that had not been assigned to a known chromosome on chicken genome build WASHUC2 were included in this study, no new linkage groups were found. The resulting linkage map is composed of 31 linkage groups, with a total length of 3,054 cM for the sex-average map of the combined population. The sex-average linkage map of the purebred broiler line is 686 cM smaller than the linkage map of the broiler × broiler cross. Conclusions In this study, we present a linkage map of the chicken genome at a substantially higher resolution than previously published linkage maps. Regional differences in recombination hotspots between the two mapping populations were observed in several chromosomes near the telomere of the p arm; the sex-specific analysis revealed that these regional differences were mainly caused by female-specific recombination hotspots in the broiler × broiler cross. PMID:20141624

  17. Thermoelastic stress in oceanic lithosphere due to hotspot reheating

    NASA Technical Reports Server (NTRS)

    Zhu, Anning; Wiens, Douglas A.

    1991-01-01

    The effect of hotspot reheating on the intraplate stress field is investigated by modeling the three-dimensional thermal stress field produced by nonuniform temperature changes in an elastic plate. Temperature perturbations are calculated assuming that the lithosphere is heated by a source in the lower part of the thermal lithosphere. A thermal stress model for the elastic lithosphere is calculated by superposing the stress fields resulting from temperature changes in small individual elements. The stress in an elastic plate resulting from a temperature change in each small element is expressed as an infinite series, wherein each term is a source or an image modified from a closed-from half-space solution. The thermal stress solution is applied to midplate swells in oceanic lithosphere with various thermal structures and plate velocities. The results predict a stress field with a maximum deviatoric stress on the order of 100 MPa covering a broad area around the hotspot plume. The predicted principal stress orientations show a complicated geographical pattern, with horizontal extension perpendicular to the hotspot track at shallow depths and compression along the track near the bottom of the elastic lithosphere.

  18. Thermoelastic stress in oceanic lithosphere due to hotspot reheating

    NASA Technical Reports Server (NTRS)

    Zhu, Anning; Wiens, Douglas A.

    1991-01-01

    The effect of hotspot reheating on the intraplate stress field is investigated by modeling the three-dimensional thermal stress field produced by nonuniform temperature changes in an elastic plate. Temperature perturbations are calculated assuming that the lithosphere is heated by a source in the lower part of the thermal lithosphere. A thermal stress model for the elastic lithosphere is calculated by superposing the stress fields resulting from temperature changes in small individual elements. The stress in an elastic plate resulting from a temperature change in each small element is expressed as an infinite series, wherein each term is a source or an image modified from a closed-from half-space solution. The thermal stress solution is applied to midplate swells in oceanic lithosphere with various thermal structures and plate velocities. The results predict a stress field with a maximum deviatoric stress on the order of 100 MPa covering a broad area around the hotspot plume. The predicted principal stress orientations show a complicated geographical pattern, with horizontal extension perpendicular to the hotspot track at shallow depths and compression along the track near the bottom of the elastic lithosphere.

  19. Volcanic hotspots on Io - Stability and longitudinal distribution

    NASA Technical Reports Server (NTRS)

    Johnson, T. V.; Matson, D. L.; Veeder, G. J.; Nelson, R. M.; Morrison, D.; Brown, R. H.

    1984-01-01

    The first results of a program to determine the longitudinal distribution of volcanic activity on Jupiter's satellite Io are presented. Infrared measurements at 8.7, 10, and 20 micrometers have been taken at a variety of orbital longitudes: strong variation in the 8.7- and 10-micrometer flux with longitude demonstrates that infrared emission arising from volcanic hotspots on Io is strongly concentrated in a few locations. Analysis of these data suggests that the active volcanic regions observed by the Voyager experimenters are still active, particularly the region around the feature known as Loki. Another source of flux, although of somewhat smaller magnitude, is indicated on the opposite hemisphere. If these sources are the only major volcanic centers on Io, then current global heat flow estimates must be revised downward. However, heat flow from as yet unobserved longitudes, hotspots at high latitudes, and conducted heat flow must still be measured.

  20. Interventions to reduce suicides at suicide hotspots: a systematic review

    PubMed Central

    2013-01-01

    Background ‘Suicide hotspots’ include tall structures (for example, bridges and cliffs), railway tracks, and isolated locations (for example, rural car parks) which offer direct means for suicide or seclusion that prevents intervention. Methods We searched Medline for studies that could inform the following question: ‘What interventions are available to reduce suicides at hotspots, and are they effective?’ Results There are four main approaches: (a) restricting access to means (through installation of physical barriers); (b) encouraging help-seeking (by placement of signs and telephones); (c) increasing the likelihood of intervention by a third party (through surveillance and staff training); and (d) encouraging responsible media reporting of suicide (through guidelines for journalists). There is relatively strong evidence that reducing access to means can avert suicides at hotspots without substitution effects. The evidence is weaker for the other approaches, although they show promise. Conclusions More well-designed intervention studies are needed to strengthen this evidence base. PMID:23496989

  1. Volcanic hotspots on io: stability and longitudinal distribution.

    PubMed

    Johnson, T V; Morrison, D; Matson, D L; Veeder, G J; Brown, R H; Nelson, R M

    1984-10-12

    We report the first results of a program to determine the longitudinal distribution of volcanic activity on Jupiter's satellite Io. Infrared measurements at 8.7, 10, and 20 micrometers have been taken at a variety of orbital longitudes: strong variation in the 8.7- and 10-micrometer flux with longitude demonstrates that infrared emission arising from volcanic hotspots on Io is strongly concentrated in a few locations. Analysis of these data suggests that the active volcanic regions observed by the Voyager experimenters are still active, particularly the region around the feature known as Loki. Another source of flux, although of somewhat smaller magnitude, is indicated on the opposite hemisphere. If these sources are the only major volcanic centers on Io, then current global heat flow estimates must be revised downward. However, heat flow from as yet unobserved longitudes, hotspots at high latitudes, and conducted heat flow must still be measured.

  2. Medical radiation exposure and risk of retinoblastoma resulting from new germline RB1 mutation.

    PubMed

    Bunin, Greta R; Felice, Marc A; Davidson, William; Friedman, Debra L; Shields, Carol L; Maidment, Andrew; O'Shea, Michael; Nichols, Kim E; Leahey, Ann; Dunkel, Ira J; Jubran, Rima; Rodriguez-Galindo, Carlos; Schmidt, Mary Lou; Weinstein, Joanna L; Goldman, Stewart; Abramson, David H; Wilson, Matthew W; Gallie, Brenda L; Chan, Helen S L; Shapiro, Michael; Cnaan, Avital; Ganguly, Arupa; Meadows, Anna T

    2011-05-15

    Although ionizing radiation induces germline mutations in animals, human studies of radiation-exposed populations have not detected an effect. We conducted a case-control study of sporadic bilateral retinoblastoma, which results from a new germline RB1 mutation, to investigate gonadal radiation exposure of parents from medical sources before their child's conception. Parents of 206 cases from nine North American institutions and 269 controls participated; fathers of 184 cases and 223 friend and relative controls and mothers of 204 cases and 260 controls provided information in telephone interviews on their medical radiation exposure. Cases provided DNA for RB1 mutation testing. Of common procedures, lower gastrointestinal (GI) series conferred the highest estimated dose to testes and ovaries. Paternal history of lower GI series was associated with increased risk of retinoblastoma in the child [matched odds ratio (OR) = 3.6, 95% confidence interval (CI) = 1.2-11.2, two-sided p = 0.02], as was estimated total testicular dose from all procedures combined (OR for highest dose=3.9, 95% CI = 1.2-14.4, p = 0.02). Maternal history of lower GI series was also associated with increased risk (OR = 7.6, 95% CI = 2.8-20.7, p < 0.001) as was the estimated total dose (OR for highest dose = 3.0, 95% CI = 1.4-7.0, p = 0.005). The RB1 mutation spectrum in cases of exposed parents did not differ from that of other cases. Some animal and human data support our findings of an association of gonadal radiation exposure in men and women with new germline RB1 mutation detectable in their children, although bias, confounding, and/or chance may also explain the results.

  3. Medical radiation exposure and risk of retinoblastoma resulting from new germline RB1 mutation

    PubMed Central

    Bunin, Greta R; Felice, Marc A.; Davidson, William; Friedman, Debra L; Shields, Carol L; Maidment, Andrew; O'Shea, Michael; Nichols, Kim E; Leahey, Ann; Dunkel, Ira J; Jubran, Rima; Rodriguez-Galindo, Carlos; Schmidt, Mary Lou; Weinstein, Joanna L; Goldman, Stewart; Abramson, David H; Wilson, Matthew W; Gallie, Brenda L; Chan, Helen S L; Shapiro, Michael; Cnaan, Avital; Ganguly, Arupa; Meadows, Anna T

    2011-01-01

    Although ionizing radiation induces germline mutations in animals, human studies of radiation-exposed populations have not detected an effect. We conducted a case-control study of sporadic bilateral retinoblastoma, which results from a new germline RB1 mutation, to investigate gonadal radiation exposure of parents from medical sources before their child's conception. Parents of 206 cases from 9 North American institutions and 269 controls participated; fathers of 184 cases and 223 friend and relative controls and mothers of 204 cases and 260 controls provided information in telephone interviews on their medical radiation exposure. Cases provided DNA for RB1 mutation testing. Of common procedures, lower GI series conferred the highest estimated dose to testes and ovaries. Paternal history of lower GI series was associated with increased risk of retinoblastoma in the child (matched odds ratio (OR)=3.6, 95% confidence interval (CI) 1.2, 11.2, 2-sided P=0.02), as was estimated total testicular dose from all procedures combined (OR for highest dose=3.9, 95% CI 1.2, 14.4, P =0.02). Maternal history of lower GI series was also associated with increased risk (OR=7.6, 95% CI 2.8, 20.7, P <0.001) as was estimated total dose (OR for highest dose=3.0, 95% CI 1.4, 7.0, P =0.005). The RB1 mutation spectrum in cases of exposed parents did not differ from that of other cases. Some animal and human data support our findings of an association of gonadal radiation exposure in men and women with new germline RB1 mutation detectable in their children, although bias, confounding, and/or chance may also explain the results. PMID:20648557

  4. Radiative properties of a plasma moving across a magnetic field. I - Theoretical analysis. II - Numerical results

    NASA Technical Reports Server (NTRS)

    Roussel-Dupre, Robert; Miller, Ronald H.

    1993-01-01

    The early-time evolution of plasmas moving across a background magnetic field is addressed with a 2D model in which a plasma cloud is assumed to have formed instantaneously with a velocity across a uniform background magnetic field and with a Gaussian density profile in the two dimensions perpendicular to the direction of motion. This model treats both the dynamics associated with the formation of a polarization field and the generation and propagation of electromagnetic waves. In general, the results indicate that, to zeroth order, the plasma cloud behaves like a large dipole antenna oriented in the direction of the polarization field which oscillates at frequencies defined by the normal mode of the system. Radiation damping is shown to play an important role in defining the plasma cloud evolution, causing a rapid decay of the polarizaiton field and a loss of plasma kinetic energy and momentum on time scales comprable to several ion gyroperiods. Scaling laws are derived for the plasma momentum and energy loss rates, and predictions for the braking time, the amplitude and spectrum of the radiation field, and the total radiated power are presented for conditions relevant to the recent Combined Release and Radiation Effects Satellite experiments.

  5. Predator diversity hotspots in the blue ocean.

    PubMed

    Worm, Boris; Lotze, Heike K; Myers, Ransom A

    2003-08-19

    Concentrations of biodiversity, or hotspots, represent conservation priorities in terrestrial ecosystems but remain largely unexplored in marine habitats. In the open ocean, many large predators such as tunas, sharks, billfishes, and sea turtles are of current conservation concern because of their vulnerability to overfishing and ecosystem role. Here we use scientific-observer records from pelagic longline fisheries in the Atlantic and Pacific Oceans to show that oceanic predators concentrate in distinct diversity hotspots. Predator diversity consistently peaks at intermediate latitudes (20-30 degrees N and S), where tropical and temperate species ranges overlap. Individual hotspots are found close to prominent habitat features such as reefs, shelf breaks, or seamounts and often coincide with zooplankton and coral reef hotspots. Closed-area models in the northwest Atlantic predict that protection of hotspots outperforms other area closures in safeguarding threatened pelagic predators from ecological extinction. We conclude that the seemingly monotonous landscape of the open ocean shows rich structure in species diversity and that these features should be used to focus future conservation efforts.

  6. Meiotic recombination hotspots - a comparative view.

    PubMed

    Choi, Kyuha; Henderson, Ian R

    2015-07-01

    During meiosis homologous chromosomes pair and undergo reciprocal genetic exchange, termed crossover. Meiotic recombination has a profound effect on patterns of genetic variation and is an important tool during crop breeding. Crossovers initiate from programmed DNA double-stranded breaks that are processed to form single-stranded DNA, which can invade a homologous chromosome. Strand invasion events mature into double Holliday junctions that can be resolved as crossovers. Extensive variation in the frequency of meiotic recombination occurs along chromosomes and is typically focused in narrow hotspots, observed both at the level of DNA breaks and final crossovers. We review methodologies to profile hotspots at different steps of the meiotic recombination pathway that have been used in different eukaryote species. We then discuss what these studies have revealed concerning specification of hotspot locations and activity and the contributions of both genetic and epigenetic factors. Understanding hotspots is important for interpreting patterns of genetic variation in populations and how eukaryotic genomes evolve. In addition, manipulation of hotspots will allow us to accelerate crop breeding, where meiotic recombination distributions can be limiting. © 2015 The Authors The Plant Journal © 2015 John Wiley & Sons Ltd.

  7. Flood risk assessment of land pollution hotspots

    NASA Astrophysics Data System (ADS)

    Masi, Matteo; Arrighi, Chiara; Iannelli, Renato

    2017-04-01

    Among the risks caused by extreme events, the potential spread of pollutants stored in land hotspots due to floods is an aspect that has been rarely examined with a risk-based approach. In this contribution, an attempt to estimate pollution risks related to flood events of land pollution hotspots was carried out. Flood risk has been defined as the combination of river flood hazard, hotspots exposure and vulnerability to contamination of the area, i.e. the expected severity of the environmental impacts. The assessment was performed on a geographical basis, using geo-referenced open data, available from databases of land management institutions, authorities and agencies. The list of land pollution hotspots included landfills and other waste handling facilities (e.g., temporary storage, treatment and recycling sites), municipal wastewater treatment plants, liquid waste treatment facilities and contaminated sites. The assessment was carried out by combining geo-referenced data of pollution hotspots with flood hazard maps. We derived maps of land pollution risk based on geographical and geological properties and source characteristics available from environmental authorities. These included information about soil particle size, soil hydraulic conductivity, terrain slope, type of stored pollutants, the type of facility, capacity, size of the area, land use, etc. The analysis was carried out at catchment scale. The case study of the Arno river basin in Tuscany (central Italy) is presented.

  8. Recombination hotspots: Models and tools for detection.

    PubMed

    Paul, Prosenjit; Nag, Debjyoti; Chakraborty, Supriyo

    2016-04-01

    Recombination hotspots are the regions within the genome where the rate, and the frequency of recombination are optimum with a size varying from 1 to 2kb. The recombination event is mediated by the double-stranded break formation, guided by the combined enzymatic action of DNA topoisomerase and Spo 11 endonuclease. These regions are distributed non-uniformly throughout the human genome and cause distortions in the genetic map. Numerous lines of evidence suggest that the number of hotspots known in humans has increased manifold in recent years. A few facts about the hotspot evolutions were also put forward, indicating the differences in the hotspot position between chimpanzees and humans. In mice, recombination hot spots were found to be clustered within the major histocompatibility complex (MHC) region. Several models, that help explain meiotic recombination has been proposed. Moreover, scientists also developed some computational tools to locate the hotspot position and estimate their recombination rate in humans is of great interest to population and medical geneticists. Here we reviewed the molecular mechanisms, models and in silico prediction techniques of hot spot residues.

  9. Limited Latitudinal Motion of the Louisville Hotspot

    NASA Astrophysics Data System (ADS)

    Koppers, A. A.; Yamazaki, T.; Geldmacher, J.; Gee, J. S.; Pressling, N.; Hoshi, H.

    2012-12-01

    Integrated Ocean Drilling Program (IODP) Expedition 330 drilled five different guyots in the Louisville Seamount Trail ranging in age between 80 and 50 Ma. Two of the primary goals of this expedition were to attain high-quality estimates of the Louisville hotspot paleolatitudes using paleomagnetic measurements and to improve our knowledge of the overall age progression using high-precision 40Ar/39Ar geochronology. With these data we can provide the unique record of the paleolatitude shift (or lack thereof) of the Louisville mantle plume and compare it with the ~15° paleolatitude shift observed for seamounts in the Hawaiian-Emperor Seamount Trail over the same time period. We show that the Louisville hotspot remained within ~3° of its present-day ~51°S latitude between 70 and 50 Ma, although we cannot discount more significant southward motion since 74 Ma. Our new paleolatitude and age data suggest there has been significant inter-hotspot motion between the Hawaiian and Louisville hotspots in this time interval. We therefore conclude that the Louisville and Hawaiian hotspots moved independently and not as part of a large-scale mantle wind.

  10. Determination of hot-spot susceptibility of multistring photovoltaic modules in a central-station application

    NASA Technical Reports Server (NTRS)

    Gonzalez, C. C.; Weaver, R. W.; Ross, R. G., Jr.; Spencer, R.; Arnett, J. C.

    1984-01-01

    Part of the effort of the Jet Propulsion Laboratory (JPL) Flat-Plate Solar Array Project (FSA) includes a program to improve module and array reliability. A collaborative activity with industry dealing with the problem of hot-spot heating due to the shadowing of photovoltaic cells in modules and arrays containing several paralleled cell strings is described. The use of multiparallel strings in large central-station arrays introduces the likelihood of unequal current sharing and increased heating levels. Test results that relate power dissipated, current imbalance, cross-strapping frequency, and shadow configuration to hot-spot heating levels are presented. Recommendations for circuit design configurations appropriate to central-station applications that reduce the risk of hot-spot problems are offered. Guidelines are provided for developing hot-spot tests for arrays when current imbalance is a threat.

  11. Determination of hot-spot susceptibility of multistring photovoltaic modules in a central-station application

    NASA Technical Reports Server (NTRS)

    Gonzalez, C. C.; Weaver, R. W.; Ross, R. G., Jr.; Spencer, R.; Arnett, J. C.

    1984-01-01

    Part of the effort of the Jet Propulsion Laboratory (JPL) Flat-Plate Solar Array Project (FSA) includes a program to improve module and array reliability. A collaborative activity with industry dealing with the problem of hot-spot heating due to the shadowing of photovoltaic cells in modules and arrays containing several paralleled cell strings is described. The use of multiparallel strings in large central-station arrays introduces the likelihood of unequal current sharing and increased heating levels. Test results that relate power dissipated, current imbalance, cross-strapping frequency, and shadow configuration to hot-spot heating levels are presented. Recommendations for circuit design configurations appropriate to central-station applications that reduce the risk of hot-spot problems are offered. Guidelines are provided for developing hot-spot tests for arrays when current imbalance is a threat.

  12. Mouse tetrad analysis provides insights into recombination mechanisms and hotspot evolutionary dynamics.

    PubMed

    Cole, Francesca; Baudat, Frédéric; Grey, Corinne; Keeney, Scott; de Massy, Bernard; Jasin, Maria

    2014-10-01

    The ability to examine all chromatids from a single meiosis in yeast tetrads has been indispensable for defining the mechanisms of homologous recombination initiated by DNA double-strand breaks (DSBs). Using a broadly applicable strategy for the analysis of chromatids from a single meiosis at two recombination hotspots in mouse oocytes and spermatocytes, we demonstrate here the unidirectional transfer of information-gene conversion-in both crossovers and noncrossovers. Whereas gene conversion in crossovers is associated with reciprocal exchange, the unbroken chromatid is not altered in noncrossover gene conversion events, providing strong evidence that noncrossovers arise from a distinct pathway. Gene conversion frequently spares the binding site of the hotspot-specifying protein PRDM9, with the result that erosion of the hotspot is slowed. Thus, mouse tetrad analysis demonstrates how unique aspects of mammalian recombination mechanisms shape hotspot evolutionary dynamics.

  13. Shock-induced hotspot formation and chemical reaction initiation in PETN containing a spherical void

    NASA Astrophysics Data System (ADS)

    Shan, Tzu-Ray; Thompson, Aidan P.

    2014-05-01

    We present results of reactive molecular dynamics simulations of hotspot formation and chemical reaction initiation in shock-induced compression of pentaerythritol tetranitrate (PETN) with the ReaxFF reactive force field. A supported shockwave is driven through a PETN crystal containing a 20 nm spherical void at a sub-threshold impact velocity of 2 km/s. Formation of a hotspot due to shock-induced void collapse is observed. During void collapse, NO2 is the dominant species ejected from the upstream void surface. Once the ejecta collide with the downstream void surface and the hotspot develops, formation of final products such as N2 and H2O is observed. The simulation provides a detailed picture of how void collapse and hotspot formation leads to initiation at sub-threshold impact velocities.

  14. Hotspot detection using space-time scan statistics on children under five years of age in Depok

    NASA Astrophysics Data System (ADS)

    Verdiana, Miranti; Widyaningsih, Yekti

    2017-03-01

    Some problems that affect the health level in Depok is the high malnutrition rates from year to year and the more spread infectious and non-communicable diseases in some areas. Children under five years old is a vulnerable part of population to get the malnutrition and diseases. Based on this reason, it is important to observe the location and time, where and when, malnutrition in Depok happened in high intensity. To obtain the location and time of the hotspots of malnutrition and diseases that attack children under five years old, space-time scan statistics method can be used. Space-time scan statistic is a hotspot detection method, where the area and time of information and time are taken into account simultaneously in detecting the hotspots. This method detects a hotspot with a cylindrical scanning window: the cylindrical pedestal describes the area, and the height of cylinder describe the time. Cylinders formed is a hotspot candidate that may occur, which require testing of hypotheses, whether a cylinder can be summed up as a hotspot. Hotspot detection in this study carried out by forming a combination of several variables. Some combination of variables provides hotspot detection results that tend to be the same, so as to form groups (clusters). In the case of infant health level in Depok city, Beji health care center region in 2011-2012 is a hotspot. According to the combination of the variables used in the detection of hotspots, Beji health care center is most frequently as a hotspot. Hopefully the local government can take the right policy to improve the health level of children under five in the city of Depok.

  15. [Results of the studies on radiation ecology and radiation biology at the Institute of Biology of Komi Science Center of Ural division of Russian Academy of Science (on 40th anniversary of the Department of Radiation Ecology)].

    PubMed

    Taskaev, A I; Kudiasheva, A G; Popova, O N; Materiĭ, L D; Shuktomova, I I; Frolova, N P; Kozubov, G M; Zaĭnullin, V G; Ermakova, O V; Rakin, A O; Bashlykova, L A

    2000-01-01

    Information about the foundation and history of the Radiation Ecology Department and results of the researches on the effect of increased background radiation level on plant and animal populations, migration of radionuclides in natural biocoenosies with increased radiation level are presented.

  16. Characterizing local biological hotspots in the Gulf of Maine using remote sensing data

    NASA Astrophysics Data System (ADS)

    Ribera, Marta M.

    Researchers increasingly advocate the use of ecosystem-based management (EBM) for managing complex marine ecosystems. This approach requires managers to focus on processes and cross-scale interactions, rather than individual components. However, they often lack appropriate tools and data sources to pursue this change in management approach. One method that has been proposed to understand the ecological complexity inherent in marine ecosystems is the study of biological hotspots. Biological hotspots are locations where organisms from different trophic levels aggregate to feed on abundant supplies, and they are considered a first step toward understanding the processes driving spatial and temporal heterogeneity in marine systems. Biological hotspots are supported by phytoplankton aggregations, which are characterized by high spatial and temporal variability. As a result, methods developed to locate biological hotspots in relatively stable terrestrial systems are not well suited for more dynamic marine ecosystems. The main objective of this thesis is thus to identify and characterize local-scale biological hotspots in the western side of the Gulf of Maine. The first chapter describes a new methodological framework with the steps needed to locate these types of hotspots in marine ecosystems using remote sensing datasets. Then, in the second chapter these hotspots are characterized using a novel metric that uses time series information and spatial statistics to account for both the temporal variability and spatial structure of these marine aggregations. This metric redefines biological hotspots as areas with a high probability of exhibiting positive anomalies of productivity compared to the expected regional seasonal pattern. Finally, the third chapter compares the resulting biological hotspots to fishery-dependent abundance indices of surface and benthic predators to determine the effect of the location and magnitude of phytoplankton aggregations on the rest of the

  17. Assessing Northern Hemisphere Land-Atmosphere Hotspots Using Dynamical Adjustment

    NASA Astrophysics Data System (ADS)

    Merrifield, Anna; Lehner, Flavio; Deser, Clara; Xie, Shang-Ping

    2017-04-01

    Understanding the influence of soil moisture on surface air temperature (SAT) is made more challenging by large-scale, internal atmospheric variability present in the midlatitude summer atmosphere. In this study, dynamical adjustment is used to characterize and remove summer SAT variability associated with large-scale circulation patterns in the Community Earth System Model large ensemble (CESM-LE). The adjustment is performed over North America and Europe with two different circulation indicators: sea level pressure (SLP) and 500mb height (Z500). The removal of dynamical "noise" leaves residual SAT variability in the central U.S. and Mediterranean regions identified as hotspots of land-atmosphere interaction (e.g. Koster et al. 2004, Seneviratne et al. 2006). The residual SAT variability "signal" is not clearly related to modes of sea surface temperature (SST) variability, but is related to local soil moisture, evaporative fraction, and radiation availability. These local relationships suggest that residual SAT variability is representative of the aggregate land surface signal. SLP dynamical adjustment removes ˜15% more variability in the central U.S. hotspot region than Z500 dynamical adjustment. Similar amounts of variability are removed by SLP and Z500 in the Mediterranean region. Differences in SLP and Z500 signal magnitude in the central U.S. are likely due to the modification of SLP by local land surface conditions, while the proximity of European hotspots to the Mediterranean sea mitigates the land surface influence. Variations in the Z500 field more closely resemble large-scale midlatitude circulation patterns and therefore Z500 may be a more suitable circulation indicator for summer dynamical adjustment. Changes in the residual SAT variability signal under increased greenhouse gas forcing will also be explored.

  18. Radiation therapy for Ewing's sarcoma: Results from Memorial Sloan-Kettering in the modern era

    SciTech Connect

    La, Trang H.; Meyers, Paul A.; Wexler, Leonard H.; Alektiar, Kaled M.; Healey, John H.; Laquaglia, Michael P.; Boland, Patrick J.; Wolden, Suzanne L. . E-mail: woldens@mskcc.org

    2006-02-01

    Purpose: To evaluate the outcomes of patients with Ewing's sarcoma family of tumors (ESFT) treated with modern radiotherapy techniques with MRI along with optimal chemotherapy. Methods and Materials: The records of all 60 patients with ESFT who received radiation to the primary site between 1990 and 2004 were reviewed. All patients received chemotherapy, including vincristine, doxorubicin, cyclophosphamide, ifosfamide, and etoposide. Radiation was used as the sole modality for local control in 31 patients and was given either before (n = 3) or after surgical resection (n = 26) in the remainder. All patients had MRI and CT scan-based treatment planning, and 43% received intensity-modulated radiation therapy. Radiation doses ranged from 30 Gy to 60 Gy (median, 51 Gy), and 35% received hyperfractionated radiotherapy. Results: Median age was 16 years (range, 2-40 years). Because of selection bias for radiotherapy, the majority of primary tumors were centrally located (72%): spine (n = 18), pelvis (n = 15), extremities (n 12), chest wall (n = 5), head and neck (n = 5), and other (n = 5). Thirty-eight percent of patients presented with metastatic disease, and 52% of primary tumors were {>=}8 cm. Actuarial 3-year local control was 77%. The presence of metastases at diagnosis was an adverse prognostic factor for local control (84% vs. 61%, p = 0.036). No other predictive factors for local failure were identified. In patients without metastatic disease, 3-year disease-free and overall survival rates were 70% and 86%, respectively, whereas in patients with metastases they were both 21%. Follow-up of surviving patients was 6-178 months (median, 41 months). Conclusion: In this unfavorable cohort of ESFT patients, radiation therapy was an effective modality for local control, especially for patients without metastases. The presence of metastases at diagnosis is a predictive factor not only for death but also for local failure.

  19. ARG-walker: inference of individual specific strengths of meiotic recombination hotspots by population genomics analysis

    PubMed Central

    2015-01-01

    Background Meiotic recombination hotspots play important roles in various aspects of genomics, but the underlying mechanisms for regulating the locations and strengths of recombination hotspots are not yet fully revealed. Most existing algorithms for estimating recombination rates from sequence polymorphism data can only output average recombination rates of a population, although there is evidence for the heterogeneity in recombination rates among individuals. For genome-wide association studies (GWAS) of recombination hotspots, an efficient algorithm that estimates the individualized strengths of recombination hotspots is highly desirable. Results In this work, we propose a novel graph mining algorithm named ARG-walker, based on random walks on ancestral recombination graphs (ARG), to estimate individual-specific recombination hotspot strengths. Extensive simulations demonstrate that ARG-walker is able to distinguish the hot allele of a recombination hotspot from the cold allele. Integrated with output of ARG-walker, we performed GWAS on the phased haplotype data of the 22 autosome chromosomes of the HapMap Asian population samples of Chinese and Japanese (JPT+CHB). Significant cis-regulatory signals have been detected, which is corroborated by the enrichment of the well-known 13-mer motif CCNCCNTNNCCNC of PRDM9 protein. Moreover, two new DNA motifs have been identified in the flanking regions of the significantly associated SNPs (single nucleotide polymorphisms), which are likely to be new cis-regulatory elements of meiotic recombination hotspots of the human genome. Conclusions Our results on both simulated and real data suggest that ARG-walker is a promising new method for estimating the individual recombination variations. In the future, it could be used to uncover the mechanisms of recombination regulation and human diseases related with recombination hotspots. PMID:26679564

  20. Analysis of microstructure-dependent shock dissipation and hot-spot formation in granular metalized explosive

    NASA Astrophysics Data System (ADS)

    Chakravarthy, Sunada; Gonthier, Keith A.

    2016-07-01

    Variations in the microstructure of granular explosives (i.e., particle packing density, size, shape, and composition) can affect their shock sensitivity by altering thermomechanical fields at the particle-scale during pore collapse within shocks. If the deformation rate is fast, hot-spots can form, ignite, and interact, resulting in burn at the macro-scale. In this study, a two-dimensional finite and discrete element technique is used to simulate and examine shock-induced dissipation and hot-spot formation within low density explosives (68%-84% theoretical maximum density (TMD)) consisting of large ensembles of HMX (C4H8N8O8) and aluminum (Al) particles (size ˜ 60 -360 μm). Emphasis is placed on identifying how the inclusion of Al influences effective shock dissipation and hot-spot fields relative to equivalent ensembles of neat/pure HMX for shocks that are sufficiently strong to eliminate porosity. Spatially distributed hot-spot fields are characterized by their number density and area fraction enabling their dynamics to be described in terms of nucleation, growth, and agglomeration-dominated phases with increasing shock strength. For fixed shock particle speed, predictions indicate that decreasing packing density enhances shock dissipation and hot-spot formation, and that the inclusion of Al increases dissipation relative to neat HMX by pressure enhanced compaction resulting in fewer but larger HMX hot-spots. Ensembles having bimodal particle sizes are shown to significantly affect hot-spot dynamics by altering the spatial distribution of hot-spots behind shocks.

  1. A hotspot model for leaf canopies

    NASA Technical Reports Server (NTRS)

    Jupp, David L. B.; Strahler, Alan H.

    1991-01-01

    The hotspot effect, which provides important information about canopy structure, is modeled using general principles of environmental physics as driven by parameters of interest in remote sensing, such as leaf size, leaf shape, leaf area index, and leaf angle distribution. Specific examples are derived for canopies of horizontal leaves. The hotspot effect is implemented within the framework of the model developed by Suits (1972) for a canopy of leaves to illustrate what might occur in an agricultural crop. Because the hotspot effect arises from very basic geometrical principles and is scale-free, it occurs similarly in woodlands, forests, crops, rough soil surfaces, and clouds. The scaling principles advanced are also significant factors in the production of image spatial and angular variance and covariance which can be used to assess land cover structure through remote sensing.

  2. Plate tectonics and hotspots: the third dimension.

    PubMed

    Anderson, D L; Tanimoto, T; Zhang, Y S

    1992-06-19

    High-resolution seismic tomographic models of the upper mantle provide powerful new constraints on theories of plate tectonics and hotspots. Midocean ridges have extremely low seismic velocities to a depth of 100 kilometers. These low velocities imply partial melting. At greater depths, low-velocity and high-velocity anomalies record, respectively, previous positions of migrating ridges and trenches. Extensional, rifting, and hotspot regions have deep (> 200 kilometers) low-velocity anomalies. The upper mantle is characterized by vast domains of high temperature rather than small regions surrounding hotspots; the asthenosphere is not homogeneous or isothermal. Extensive magmatism requires a combination of hot upper mantle and suitable lithospheric conditions. High-velocity regions of the upper 200 kilometers of the mantle correlate with Archean cratons.

  3. Evolution of midplate hotspot swells: Numerical solutions

    NASA Technical Reports Server (NTRS)

    Liu, Mian; Chase, Clement G.

    1990-01-01

    The evolution of midplate hotspot swells on an oceanic plate moving over a hot, upwelling mantle plume is numerically simulated. The plume supplies a Gaussian-shaped thermal perturbation and thermally-induced dynamic support. The lithosphere is treated as a thermal boundary layer with a strongly temperature-dependent viscosity. The two fundamental mechanisms of transferring heat, conduction and convection, during the interaction of the lithosphere with the mantle plume are considered. The transient heat transfer equations, with boundary conditions varying in both time and space, are solved in cylindrical coordinates using the finite difference ADI (alternating direction implicit) method on a 100 x 100 grid. The topography, geoid anomaly, and heat flow anomaly of the Hawaiian swell and the Bermuda rise are used to constrain the models. Results confirm the conclusion of previous works that the Hawaiian swell can not be explained by conductive heating alone, even if extremely high thermal perturbation is allowed. On the other hand, the model of convective thinning predicts successfully the topography, geoid anomaly, and the heat flow anomaly around the Hawaiian islands, as well as the changes in the topography and anomalous heat flow along the Hawaiian volcanic chain.

  4. Tabulation of Mie scattering calculation results for microwave radiative transfer modeling

    NASA Technical Reports Server (NTRS)

    Yeh, Hwa-Young M.; Prasad, N.

    1988-01-01

    In microwave radiative transfer model simulations, the Mie calculations usually consume the majority of the computer time necessary for the calculations (70 to 86 percent for frequencies ranging from 6.6 to 183 GHz). For a large array of atmospheric profiles, the repeated calculations of the Mie codes make the radiative transfer computations not only expensive, but sometimes impossible. It is desirable, therefore, to develop a set of Mie tables to replace the Mie codes for the designated ranges of temperature and frequency in the microwave radiative transfer calculation. Results of using the Mie tables in the transfer calculations show that the total CPU time (IBM 3081) used for the modeling simulation is reduced by a factor of 7 to 16, depending on the frequency. The tables are tested by computing the upwelling radiance of 144 atmospheric profiles generated by a 3-D cloud model (Tao, 1986). Results are compared with those using Mie quantities computed from the Mie codes. The bias and root-mean-square deviation (RMSD) of the model results using the Mie tables, in general, are less than 1 K except for 37 and 90 GHz. Overall, neither the bias nor RMSD is worse than 1.7 K for any frequency and any viewing angle.

  5. A biophysical model for estimating the frequency of radiation-induced mutations resulting from chromosomal translocations

    NASA Astrophysics Data System (ADS)

    Wu, Honglu; Durante, Marco

    Gene mutations can be induced by radiation as a result of chromosomal translocations. A biophysical model is developed to estimate the frequency of this type of mutation induced by low-LET radiation. Mutations resulting from translocations are assumed to be formed by misrejoining of two DNA double strand breaks (DSB), one within the gene and one on a different chromosome. The chromosome containing the gene is assumed to occupy a spherical territory and does not overlap spatially with other chromosomes. Misrejoining between two DSB can occur only if the two DSB are closer than an interaction distance at the time of their induction. Applying the model to mutations of the hprt gene induced in G0 human lymphocyte cells by low-LET radiation, it is calculated that mutations resulting from translocations account for about 14% of the total mutations. The value of the interaction distance is determined to be 0.6 μm by comparing with the observed frequency of translocations in the X-chromosome.

  6. High-resolution characterization of CPD hotspot formation in human fibroblasts

    PubMed Central

    Zavala, Anamaria G.; Morris, Robert T.; Wyrick, John J.; Smerdon, Michael J.

    2014-01-01

    Repair of DNA lesions must occur within the chromatin landscape and is associated with alterations in histone modifications and nucleosome rearrangement. To directly associate these chromatin features with DNA damage and repair, it is necessary to be able to map DNA adducts. We have developed a cyclobutane pyrimidine dimer (CPD)-specific immunoprecipitation method and mapped ultraviolet damage hotspots across human chromosomes 1 and 6. CPD hotspots occur almost equally in genic and intergenic regions. However, these hotspots are significantly more prevalent adjacent to repeat elements, especially Alu repeats. Nucleosome mapping studies indicate that nucleosomes are consistently positioned at Alu elements where CPD hotspots form, but by 2 h post-irradiation, these same regions are significantly depleted of nucleosomes. These results indicate that nucleosomes associated with hotspots of CPD formation are readily rearranged, potentially making them accessible to DNA repair machinery. Our results represent the first chromosome scale map of ultraviolet-induced DNA lesions in the human genome, and reveal the sequence features and dynamic chromatin changes associated with CPD hotspots. PMID:24137003

  7. European Atlantic: the hottest oil spill hotspot worldwide

    NASA Astrophysics Data System (ADS)

    Vieites, David R.; Nieto-Román, Sandra; Palanca, Antonio; Ferrer, Xavier; Vences, Miguel

    2004-11-01

    Oil spills caused by maritime transport of petroleum products are still an important source of ocean pollution, especially in main production areas and along major transport routes. We here provide a historical and geographic analysis of the major oil spills (>700 t) since 1960. Spills were recorded from several key marine ecosystems and marine biodiversity hotspots. The past four decades have been characterized by an overall decrease in the number of accidents and tonnes of oil spilled in the sea, but this trend was less distinct in the European Atlantic area. Recent black tides from the Erika and Prestige vessels provided new evidence for the high risk of accidents with serious ecological impact in this area, which according to our analysis is historically the most important oil spill hotspot worldwide. The English Channel and waters around Galicia in Spain were the areas with most accidents. Maritime transport in European Atlantic waters has been predicted to continue increasing. Together with our own results this suggests that, in addition to measures for increased traffic safety, deployment of emergency capacities in the spill hotspot areas may be crucial for a sustainable conservation of sea resources and ecosystems.

  8. On localised hotspots of an urban crime model

    NASA Astrophysics Data System (ADS)

    Lloyd, David J. B.; O'Farrell, Hayley

    2013-06-01

    We investigate stationary, spatially localised crime hotspots on the real line and the plane of an urban crime model of Short et al. [M. Short, M. DÓrsogna, A statistical model of criminal behavior, Mathematical Models and Methods in Applied Sciences 18 (2008) 1249-1267]. Extending the weakly nonlinear analysis of Short et al., we show in one-dimension that localised hotspots should bifurcate off the background spatially homogeneous state at a Turing instability provided the bifurcation is subcritical. Using path-following techniques, we continue these hotspots and show that the bifurcating pulses can undergo the process of homoclinic snaking near the singular limit. We analyse the singular limit to explain the existence of spike solutions and compare the analytical results with the numerical computations. In two-dimensions, we show that localised radial spots should also bifurcate off the spatially homogeneous background state. Localised planar hexagon fronts and hexagon patches are found and depending on the proximity to the singular limit these solutions either undergo homoclinic snaking or act like “multi-spot” solutions. Finally, we discuss applications of these localised patterns in the urban crime context and the full agent-based model.

  9. Identification of a Hawaiian-Emperor Style Bend in the Tuvalu Segment of the Rurutu Hotspot

    NASA Astrophysics Data System (ADS)

    Finlayson, V.; Konter, J. G.; Konrad, K.; Price, A. A.; Koppers, A. A. P.; Jackson, M. G.

    2016-12-01

    Absolute plate motion (APM) models continue to improve with better characterization of drift of the two primary hotspots: Hawaii and Louisville. While APM models are more reliable from 50 Ma to modern times, uncertainty is introduced prior to 50 Ma due to hotspot track mismatch, uncertain location of the Louisville hotspot, and inter-hotspot drift as deduced from paleolatitude data [1,2]. Hawaiian hotspot drift contributed to a sharp 50 Ma Hawaiian-Emperor Bend (HEB) not reflected by the Louisville track. Adding a third HEB to the known long-lived hotspot tracks allows evaluation of APM uncertainty and hotspot drift. We present Pb-Sr-Nd-Hf isotopes and 40Ar/39Ar ages that complement existing Rurutu data [3], and for the first time trace the hotspot through its HEB back to 100 Ma. Our results reveal that the Tuvalu chain and some western Samoa seamounts define an age-progressive 63-42 Ma segment of the Rurutu track. The segment displays various mixtures between extreme endmember HIMU (206Pb/204Pb ≥ 20) and compositionally common FOZO [4,5] typical of Rurutu volcanism [3,6]. Other compositions also occur, differing in age and origin. In addition to the Rurutu-related seamounts, three seamounts were also sampled that have depleted mid-ocean ridge basalt compositions and ages that coincide with the opening of the underlying ocean basin. While distinct from the Rurutu hotspot, Samoan volcanoes overlapping 50-42 Ma Rurutu seamounts prevent straightforward identification of the HEB. Using age, composition, and location data, we project the Rurutu track with a moving hotspot APM model [7] from each age-dated seamount, defining the likeliest location with a cluster of projected HEBs. We find the Rurutu HEB occurs near the intersection of Tuvalu and western Samoa, providing a key constraint required to evaluate APM and inter-hotspot drift. 1. Koppers et al., (2012) doi:10.1038/ngeo1638 2. Tarduno et al., (2003) doi:10.1126/science.1086442 3. Konter et al., (2008) doi:10

  10. Variations in Jupiter's Radiation Belts and Synchrotron Radiation as a Result of the Impacts of Comet Shoemaker-Levy/9

    NASA Technical Reports Server (NTRS)

    Bolton, S.; Gulkis, S.; Klein, M.; Thorne, R. M.

    1995-01-01

    Changes to Jupiter's synchrotron radiation following the impact of Comet Shoemaker-Levy/9 are reported. Also, the consequences are reported for three possible mechanisms that might have caused those changes.

  11. Environmental and Microbial Features Affecting Denitrification and Anammox Hotspots in an Estuarine Ecosystem

    NASA Astrophysics Data System (ADS)

    Lisa, J.; Song, B.; Lefcheck, J. S.; Tobias, C. R.

    2016-02-01

    Biogeochemical hotspots are characterized as a few sites that exhibit extremely high reaction rates relative to surrounding area, and often account for a high percentage of the overall reaction rates in an ecosystem. Criteria for quantitatively identifying these sites have not been well established. Further, the underlying mechanisms of hotspots have been described in terms of environmental conditions, with little attention paid to the microbial community. The objectives of this study were to establish quantitative criteria to identify denitrification and anammox hotspots, and determine the underlying microbial and environmental factors responsible for elevated N2 production. We used 15N isotope pairing incubation experiments to measure denitrification and anammox rates in the New River Estuary, NC. Quantitative PCR assays of nitrous oxide reductase (nosZ Clades I and II) and hydrazine oxidoreductase (hzo) genes were conducted to estimate denitrifier and anammox abundance. Structural Equation Modeling (SEM) was used to elucidate complex causal relationships between environmental and biological variables. Denitrification hotspots, quantitatively defined as statistical outliers, accounted for 35.6% total denitrification while comprising only 7.3% of the sites. Anammox hotspots,10.6% of the sites, accounted for 60.9% of total anammox. SEM revealed increased sediment organics at lower salinities supported higher functional gene abundance, which in turn resulted in higher N2 production. Surprisingly, denitrification rates were significantly and positively correlated with nosZ Clade II gene abundance, after accounting for the non-significant contributions of the naturally more abundant nosZ Clade I, and other environmental covariates. This is the first time that a quantitative definition of biogeochemical hotspots was put forth and used to determine the importance of anammox and denitrification hotspots in estuarine nitrogen removal capacity. Despite the low area

  12. Radiation doses resulting from variations in spent fuel/waste management systems without Monitored Retrievable Storage

    SciTech Connect

    Schneider, K.J.; Pelto, P.J.; Lavender, J.C.; Daling, P.M.; Fecht, B.A.

    1987-02-01

    This paper presents results of analyses of radiological dose impacts on the public and the workers of nine potential transportation-related changes in the operation of a hypothetical high-level waste management system that does not include a Monitored Retrievable Storage (MRS) facility. The analyses were performed for the US Department of Energy (DOE) to determine if some of the benefits proposed for the improved performance waste management system (one with an MRS facility) could also benefit the authorized system (one without an MRS facility). The study showed that most of the alternatives evaluated would reduce the radiation doses to the public and the workers. Of the alternatives evaluated, the primary means for reducing these radiation doses is to increase the capacity of the transportation casks.

  13. Analysis of MIR-18 results for physical and biological dosimetry: radiation shielding effectiveness in LEO

    NASA Technical Reports Server (NTRS)

    Cucinotta, F. A.; Wilson, J. W.; Williams, J. R.; Dicello, J. F.

    2000-01-01

    We compare models of radiation transport and biological response to physical and biological dosimetry results from astronauts on the Mir space station. Transport models are shown to be in good agreement with physical measurements and indicate that the ratio of equivalent dose from the Galactic Cosmic Rays (GCR) to protons is about 3/2:1 and that this ratio will increase for exposures to internal organs. Two biological response models are used to compare to the Mir biodosimetry for chromosome aberration in lymphocyte cells; a track-structure model and the linear-quadratic model with linear energy transfer (LET) dependent weighting coefficients. These models are fit to in vitro data for aberration formation in human lymphocytes by photons and charged particles. Both models are found to be in reasonable agreement with data for aberrations in lymphocytes of Mir crew members: however there are differences between the use of LET dependent weighting factors and track structure models for assigning radiation quality factors. The major difference in the models is the increased effectiveness predicted by the track model for low charge and energy ions with LET near 10 keV/micrometers. The results of our calculations indicate that aluminum shielding, although providing important mitigation of the effects of trapped radiation, provides no protective effect from the galactic cosmic rays (GCR) in low-earth orbit (LEO) using either equivalent dose or the number of chromosome aberrations as a measure until about 100 g/cm 2 of material is used.

  14. Analysis of MIR-18 results for physical and biological dosimetry: radiation shielding effectiveness in LEO

    NASA Technical Reports Server (NTRS)

    Cucinotta, F. A.; Wilson, J. W.; Williams, J. R.; Dicello, J. F.

    2000-01-01

    We compare models of radiation transport and biological response to physical and biological dosimetry results from astronauts on the Mir space station. Transport models are shown to be in good agreement with physical measurements and indicate that the ratio of equivalent dose from the Galactic Cosmic Rays (GCR) to protons is about 3/2:1 and that this ratio will increase for exposures to internal organs. Two biological response models are used to compare to the Mir biodosimetry for chromosome aberration in lymphocyte cells; a track-structure model and the linear-quadratic model with linear energy transfer (LET) dependent weighting coefficients. These models are fit to in vitro data for aberration formation in human lymphocytes by photons and charged particles. Both models are found to be in reasonable agreement with data for aberrations in lymphocytes of Mir crew members: however there are differences between the use of LET dependent weighting factors and track structure models for assigning radiation quality factors. The major difference in the models is the increased effectiveness predicted by the track model for low charge and energy ions with LET near 10 keV/micrometers. The results of our calculations indicate that aluminum shielding, although providing important mitigation of the effects of trapped radiation, provides no protective effect from the galactic cosmic rays (GCR) in low-earth orbit (LEO) using either equivalent dose or the number of chromosome aberrations as a measure until about 100 g/cm 2 of material is used.

  15. Australian radiation laboratory (ARL) solar-UVR measurement network: calibation and results

    NASA Astrophysics Data System (ADS)

    Gies, H. P.; Roy, Colin R.; Toomey, S.; Tomlinson, D. W.

    1994-09-01

    The Australian Radiation Laboratory (ARL) has been involved for many years in the measurement of solar ultraviolet radiation (UVR) using spectroradiometers and a network of broadband detectors at 20 sites in Australia and Antarctica. Measurement sites range from polar to tropical, with vastly different weather conditions and as a result there are many difficulties associated with maintenance of the network to ensure accurate and reliable data collection. Calibration procedures for the various detector systems involve simultaneous spectral measurements using a portable spectroradiometer incorporating a double monochromator, calibrated against 1000 watt standard lamps traceable to the CSIRO National Measurement Laboratory. The spectroradiometer was also checked when ARL participated in an international intercomparison of spectroradiometers at Lauder, NZ in February 1993 and a further intercomparison takes place in Germany during 1994. Detector-datalogger systems are intercompared at the Yallambie site for a number of months before installation at another site. As an additional check on the calibrations, computer models of solar UVR at the earth's surface for days with clear sky and known ozone are compared with the UV radiometer measurements. This paper details many of the procedures and difficulties and presents some measurement results. Network data are used to determine the ultraviolet radiation (UVR) levels to which the Australian population is exposed, in educating the public with presentation of the daily UVB on the news/weather reports in the capital cities each evening, as input for epidemiological studies of skin cancer rates and for personal dosimetry studies using polysulphone film.

  16. The Planetary Accretion Shock. I. Framework for Radiation-hydrodynamical Simulations and First Results

    NASA Astrophysics Data System (ADS)

    Marleau, Gabriel-Dominique; Klahr, Hubert; Kuiper, Rolf; Mordasini, Christoph

    2017-02-01

    The key aspect determining the postformation luminosity of gas giants has long been considered to be the energetics of the accretion shock at the surface of the planet. We use one-dimensional radiation-hydrodynamical simulations to study the radiative loss efficiency and to obtain postshock temperatures and pressures and thus entropies. The efficiency is defined as the fraction of the total incoming energy flux that escapes the system (roughly the Hill sphere), taking into account the energy recycling that occurs ahead of the shock in a radiative precursor. We focus in this paper on a constant equation of state (EOS) to isolate the shock physics but use constant and tabulated opacities. While robust quantitative results will have to await a self-consistent treatment including hydrogen dissociation and ionization, the results presented here show the correct qualitative behavior and can be understood from semianalytical calculations. The shock is found to be isothermal and supercritical for a range of conditions relevant to the core accretion formation scenario (CA), with Mach numbers { M }≳ 3. Across the shock, the entropy decreases significantly by a few times {k}{{B}}/{{baryon}}. While nearly 100% of the incoming kinetic energy is converted to radiation locally, the efficiencies are found to be as low as roughly 40%, implying that a significant fraction of the total accretion energy is brought into the planet. However, for realistic parameter combinations in the CA scenario, we find that a nonzero fraction of the luminosity always escapes the Hill sphere. This luminosity could explain, at least in part, recent observations in the young LkCa 15 and HD 100546 systems.

  17. Molecular characterization of the Pb recombination hotspot in the mouse major histocompatibility complex class II region.

    PubMed

    Isobe, Taku; Yoshino, Masayasu; Mizuno, Ken-Ichi; Lindahl, Kirsten Fischer; Koide, Tsuyoshi; Gaudieri, Silvana; Gojobori, Takashi; Shiroishi, Toshihiko

    2002-08-01

    In the mouse major histocompatibility complex (MHC) class II region, meiotic recombination breakpoints are clustered in four specific sites known as hotspots. Here we reveal the primary structure of a hotspot near the Pb gene. A total of 12 crossover points were found to be confined to a 15-kb DNA segment of the Pb pseudogene. Moreover, the crossover points are concentrated in a 341-bp segment, which includes a part of exon 4 and intron 4 of the Pb gene. All four MHC hotspots appear to be located within genes or at the 3' end of genes, contrasting with characterized hotspots in budding yeast, which are mostly located at the 5'-promoter regions of genes. The Pb hotspot has several consensus motifs, an octamer transcription factor-binding sequence, the B-motif-like transcription factor-binding sequence, and tandem repeats of tetramer sequence-all of which are shared by the other three hotspots. Systematic analysis of the public database demonstrated that the full motif set occurs rarely in the nucleotide sequence of the entire MHC class II region. All results suggest that the motif set has an indispensable role in determining their site specificity.

  18. Assessment of outdoor radiofrequency electromagnetic field exposure through hotspot localization using kriging-based sequential sampling.

    PubMed

    Aerts, Sam; Deschrijver, Dirk; Verloock, Leen; Dhaene, Tom; Martens, Luc; Joseph, Wout

    2013-10-01

    In this study, a novel methodology is proposed to create heat maps that accurately pinpoint the outdoor locations with elevated exposure to radiofrequency electromagnetic fields (RF-EMF) in an extensive urban region (or, hotspots), and that would allow local authorities and epidemiologists to efficiently assess the locations and spectral composition of these hotspots, while at the same time developing a global picture of the exposure in the area. Moreover, no prior knowledge about the presence of radiofrequency radiation sources (e.g., base station parameters) is required. After building a surrogate model from the available data using kriging, the proposed method makes use of an iterative sampling strategy that selects new measurement locations at spots which are deemed to contain the most valuable information-inside hotspots or in search of them-based on the prediction uncertainty of the model. The method was tested and validated in an urban subarea of Ghent, Belgium with a size of approximately 1 km2. In total, 600 input and 50 validation measurements were performed using a broadband probe. Five hotspots were discovered and assessed, with maximum total electric-field strengths ranging from 1.3 to 3.1 V/m, satisfying the reference levels issued by the International Commission on Non-Ionizing Radiation Protection for exposure of the general public to RF-EMF. Spectrum analyzer measurements in these hotspots revealed five radiofrequency signals with a relevant contribution to the exposure. The radiofrequency radiation emitted by 900 MHz Global System for Mobile Communications (GSM) base stations was always dominant, with contributions ranging from 45% to 100%. Finally, validation of the subsequent surrogate models shows high prediction accuracy, with the final model featuring an average relative error of less than 2dB (factor 1.26 in electric-field strength), a correlation coefficient of 0.7, and a specificity of 0.96.

  19. Role of hydrodynamic instability growth in hot-spot mass gain and fusion performance of inertial confinement fusion implosions

    SciTech Connect

    Srinivasan, Bhuvana; Tang, Xian-Zhu

    2014-10-15

    In an inertial confinement fusion target, energy loss due to thermal conduction from the hot-spot will inevitably ablate fuel ice into the hot-spot, resulting in a more massive but cooler hot-spot, which negatively impacts fusion yield. Hydrodynamic mix due to Rayleigh-Taylor instability at the gas-ice interface can aggravate the problem via an increased gas-ice interfacial area across which energy transfer from the hot-spot and ice can be enhanced. Here, this mix-enhanced transport effect on hot-spot fusion-performance degradation is quantified using contrasting 1D and 2D hydrodynamic simulations, and its dependence on effective acceleration, Atwood number, and ablation speed is identified.

  20. A Globally Self-Consistent Model of Plate Motions Relative to the Hotspots for the Past 48 Million Years

    NASA Astrophysics Data System (ADS)

    Koivisto, E.; Gordon, R. G.

    2012-04-01

    Hotspots are volcanic anomalies, either in an intraplate setting or in the form of excessive volcanism along the plate boundaries, not explained by classic plate tectonics. In the early 70's, along with a deep mantle origin, hotspots were proposed to move so slowly relative to one another such that they could be used as a reference frame fixed in the deep mantle for describing plate motions in an "absolute" sense. Ever since the idea was first introduced, however, the rates of relative hotspot motion, and thus the limits of the hotspot frame of reference, have remained a source of heated debate with suggestions ranging from apparent fixity to rapid motion between the hotspots. The question of inter-hotspot motion is closely related to the estimation of true polar wander—rotation of the whole solid earth relative to the spin axis. A fundamental problem of global tectonics and paleomagnetism is determining which part of apparent polar wander—the apparent movement of age-progressive paleomagnetic poles relative to the continent in question—is due to plate motion, and which part is due to true polar wander. One approach for separating these is available if the hotspots are indeed tracking the motion of the mantle beneath the asthenosphere and are moving slowly relative to one another. In this case, a model of plate motion relative to the hotspots can be used to predict the positions of past paleomagnetic poles relative to the spin axis and thus estimate the amount of true polar wander. Cumulative improvements in the age progression along the hotspot tracks, the geomagnetic reversal time scale, and relative plate reconstructions lead to significant changes in earlier results. In this study, we build on a new method for objectively estimating plate-hotspot rotations and their uncertainties, and on our recent results that have demonstrated no significant motion between the Pacific and Indo-Atlantic hotspots since 48 Ma, and present a globally self-consistent model

  1. Airborne gamma radiation measurements of soil moisture during FIFE: Activities and results

    NASA Technical Reports Server (NTRS)

    Peck, Eugene L.

    1992-01-01

    Soil moisture measurements were obtained during the summer of 1987 and 1989 near Manhattan, Kansas, using the National Weather Service (NWS) airborne gamma radiation system. A network of 24 flight lines were established over the research area. Airborne surveys were flown daily during two intensive field campaigns. The data collected was sufficient to modify the NWS standard operational method for estimating soil moisture for the Field Experiment (FIFE) flight lines. The average root mean square error of the soil moisture estimates for shorter FIFE flight lines was found to be 2.5 percent, compared with a reported value of 3.9 percent for NWS flight lines. Techniques were developed to compute soil moisture estimates for portions of the flight lines. Results of comparisons of the airborne gamma radiation soil moisture estimates with those obtained using the NASA Pushbroom Microwave Radiation (PBMR) system and hydrological model are presented. The airborne soil moisture measurements, and real averages computed using all remotely sensed and ground data, have been in support of the research of the many FIFE investigators whose overall goal was the upscale integration of models and the application of satellite remote sensing.

  2. Estimating the Error in Statistical HAMR Object Populations Resulting from Simplified Radiation Pressure Modeling

    NASA Astrophysics Data System (ADS)

    Flegel, S.; Vörsmann, P.; Wiedemann, C.; Kebschull, C.; Braun, V.; Möckel, M.; Gelhaus, J.; Krag, H.; Klinkrad, H.

    2012-09-01

    The high-area-to-mass ratio (HAMR) object population in ESA's MASTER-2009 software (Meteoroid and Space Debris Terrestrial Environment Reference) is dominated by Multi-Layer Insulation debris at large sizes. The underlying model employs two independent mechanisms whereby Multi-Layer Insulation debris is created. These mechanisms are fragmentation events on the one hand and a deterioration process leading to the continuous release of larger objects on the other hand. All debris source models used to create the MASTER debris population rely on a semi-analytical propagator to model the major secular and long periodic orbit perturbations. The orbit parameters of HAMR objects are highly susceptive to radiation pressure effects which can result in fast secular and periodic changes for area-to-mass ratios above about 1 square meter per kilogram. The implementation of radiation pressure in this propagator is limited to the effects of solar irradiation on a spherical object and using a cylindrical Earth shadow. The current paper discusses the applicability of such a simplified theory to large statistical HAMR object populations where the main objective is not to predict the exact future location of a single object but rather to give a correct representation of the overall distribution of all HAMR objects. The basis for the current study is given by a numerical propagator which is supported by published observation results. Initially, the effects of object orientation, Earth albedo and thermal radiation on the orbit evolution are discussed. Results from published observations and simulation results give insight into the validity of the implemented model. Fundamental differences between the orbit prediction of this refined numerical propagator and the semi-analytical propagator are looked at with a view towards large statistical populations. To this end, a plausible, statistical, population of HAMR objects is propagated over an extended time period using both propagation

  3. Eliminating "Hotspots" in Digital Image Processing

    NASA Technical Reports Server (NTRS)

    Salomon, P. M.

    1984-01-01

    Signals from defective picture elements rejected. Image processing program for use with charge-coupled device (CCD) or other mosaic imager augmented with algorithm that compensates for common type of electronic defect. Algorithm prevents false interpretation of "hotspots". Used for robotics, image enhancement, image analysis and digital television.

  4. Biogeographic methods identify gymnosperm biodiversity hotspots

    NASA Astrophysics Data System (ADS)

    Contreras-Medina, Raúl; Morrone, Juan J.; Luna Vega, Isolda

    2001-10-01

    A remarkable congruence among areas of endemism, panbiogeographic nodes, and refugia in western North America, Japan, south-western China, Tasmania, and New Caledonia indicates that these areas deserve special status for conservation. Here we propose that areas identified by different biogeographic methods are significant candidates for designation as hotspots.

  5. Forecasting Hotspots-A Predictive Analytics Approach.

    PubMed

    Maciejewski, R; Hafen, R; Rudolph, S; Larew, S G; Mitchell, M A; Cleveland, W S; Ebert, D S

    2011-04-01

    Current visual analytics systems provide users with the means to explore trends in their data. Linked views and interactive displays provide insight into correlations among people, events, and places in space and time. Analysts search for events of interest through statistical tools linked to visual displays, drill down into the data, and form hypotheses based upon the available information. However, current systems stop short of predicting events. In spatiotemporal data, analysts are searching for regions of space and time with unusually high incidences of events (hotspots). In the cases where hotspots are found, analysts would like to predict how these regions may grow in order to plan resource allocation and preventative measures. Furthermore, analysts would also like to predict where future hotspots may occur. To facilitate such forecasting, we have created a predictive visual analytics toolkit that provides analysts with linked spatiotemporal and statistical analytic views. Our system models spatiotemporal events through the combination of kernel density estimation for event distribution and seasonal trend decomposition by loess smoothing for temporal predictions. We provide analysts with estimates of error in our modeling, along with spatial and temporal alerts to indicate the occurrence of statistically significant hotspots. Spatial data are distributed based on a modeling of previous event locations, thereby maintaining a temporal coherence with past events. Such tools allow analysts to perform real-time hypothesis testing, plan intervention strategies, and allocate resources to correspond to perceived threats.

  6. Hidden Hotspot Track Beneath Eastern United States

    NASA Astrophysics Data System (ADS)

    Helmberger, D. V.; Chu, R.; Leng, W.; Gurnis, M.

    2012-12-01

    More than two thirds of surface hotspots associated with volcanism can be explained by the interaction between a moving plate and deep-seated mantle plumes. Most of these hotspot tracks are observed on oceanic (Hawaii) or thin continental (Yellowstone) lithosphere. This poses the question that there could be many more hotspot tracks beneath old continental regions with thick lithospheres than suggested by the record of surface tracks. In particular, recent dating studies of kimberlites embedded throughout the North American Craton suggest possible ancient hotspot tracks to explain their age progression, Heaman et al. (2009). One of the youngest kimberlite fields is in Elliott County, Kentucky (75Ma). Although there is little surface expression for such a track, we discovered a well-developed lower lithospheric low velocity corridor passing directly beneath this site, connecting to an older kimberlite to the west and beneath the New Madrid rift zone. This apparent linear feature is about 200 km wide, 60 km thick, with a reduced P-velocity of 2.5% similar to dynamic predictions produced by a migrating plume neck and following predicted plate path. Such a high resolution feature could not have been recognized without the alignment of the Virginia earthquake with the USArray along this corridor. Here, we present the seismic evidence involving the North American Craton with its prominent 8° discontinuity and lower lithospheric fine structure.

  7. Eliminating "Hotspots" in Digital Image Processing

    NASA Technical Reports Server (NTRS)

    Salomon, P. M.

    1984-01-01

    Signals from defective picture elements rejected. Image processing program for use with charge-coupled device (CCD) or other mosaic imager augmented with algorithm that compensates for common type of electronic defect. Algorithm prevents false interpretation of "hotspots". Used for robotics, image enhancement, image analysis and digital television.

  8. Changes in Concentrations of Plasma ION-Components In Hotspot Driven By Thermodynamic Forces and their Effects on Implosions

    NASA Astrophysics Data System (ADS)

    Ho, D.; Zimmerman, G.; Kagan, G.; Amendt, P.; Rinderknecht, H.; Haan, S.; Perkins, J.; Salmonson, J.

    2016-10-01

    Changes in relative concentrations of plasma ion components driven by gradients of mass concentration, pressure, and temperature gradients, occur during shock flash and subsequent hotspot formation. This is a universal phenomenon in all laboratory implosions with two-ion component fuels, e.g., DT and D3He, occurring in the central region of the hotspot. Concentration differentials lead to noticeable yield reduction in Omega exploding pusher implosions, but not in NIF ``Symcaps'' where radiation-hydrodynamics simulations are in agreement with shot data. For all our ignition capsules designs that use a high-density carbon ablator and DT fuel adiabat α ranging from 1.5 to 4, substantial concentration differentials occur around shock flash but they are relaxed by the time of ignition resulting in no simulated yield degradation. We will provide explanations and present simulation results for this phenomenon. This work performed under auspices of U.S. DOE by LLNL under Contract DE-AC52-07NA27344.

  9. Origin of ΔN{sub eff} as a result of an interaction between dark radiation and dark matter

    SciTech Connect

    Bjaelde, Ole Eggers; Das, Subinoy; Moss, Adam E-mail: subinoy@physik.rwth-aachen.de

    2012-10-01

    Results from the Wilkinson Microwave Anisotropy Probe (WMAP), Atacama Cosmology Telescope (ACT) and recently from the South Pole Telescope (SPT) have indicated the possible existence of an extra radiation component in addition to the well known three neutrino species predicted by the Standard Model of particle physics. In this paper, we explore the possibility of the apparent extra dark radiation being linked directly to the physics of cold dark matter (CDM). In particular, we consider a generic scenario where dark radiation, as a result of an interaction, is produced directly by a fraction of the dark matter density effectively decaying into dark radiation. At an early epoch when the dark matter density is negligible, as an obvious consequence, the density of dark radiation is also very small. As the Universe approaches matter radiation equality, the dark matter density starts to dominate thereby increasing the content of dark radiation and changing the expansion rate of the Universe. As this increase in dark radiation content happens naturally after Big Bang Nucleosynthesis (BBN), it can relax the possible tension with lower values of radiation degrees of freedom measured from light element abundances compared to that of the CMB. We numerically confront this scenario with WMAP+ACT and WMAP+SPT data and derive an upper limit on the allowed fraction of dark matter decaying into dark radiation.

  10. Treatment planning systems for external whole brain radiation therapy: With and without MLC (multi leaf collimator) optimization

    NASA Astrophysics Data System (ADS)

    Budiyono, T.; Budi, W. S.; Hidayanto, E.

    2016-03-01

    Radiation therapy for brain malignancy is done by giving a dose of radiation to a whole volume of the brain (WBRT) followed by a booster at the primary tumor with more advanced techniques. Two external radiation fields given from the right and left side. Because the shape of the head, there will be an unavoidable hotspot radiation dose of greater than 107%. This study aims to optimize planning of radiation therapy using field in field multi-leaf collimator technique. A study of 15 WBRT samples with CT slices is done by adding some segments of radiation in each field of radiation and delivering appropriate dose weighting using a TPS precise plan Elekta R 2.15. Results showed that this optimization a more homogeneous radiation on CTV target volume, lower dose in healthy tissue, and reduced hotspots in CTV target volume. Comparison results of field in field multi segmented MLC technique with standard conventional technique for WBRT are: higher average minimum dose (77.25% ± 0:47%) vs (60% ± 3:35%); lower average maximum dose (110.27% ± 0.26%) vs (114.53% ± 1.56%); lower hotspot volume (5.71% vs 27.43%); and lower dose on eye lenses (right eye: 9.52% vs 18.20%); (left eye: 8.60% vs 16.53%).

  11. An Assessment of the Current US Radiation Oncology Workforce: Methodology and Global Results of the American Society for Radiation Oncology 2012 Workforce Study

    SciTech Connect

    Vichare, Anushree; Washington, Raynard; Patton, Caroline; Arnone, Anna; Olsen, Christine; Fung, Claire Y.; Hopkins, Shane; Pohar, Surjeet

    2013-12-01

    Purpose: To determine the characteristics, needs, and concerns of the current radiation oncology workforce, evaluate best practices and opportunities for improving quality and safety, and assess what we can predict about the future workforce. Methods and Materials: An online survey was distributed to 35,204 respondents from all segments of the radiation oncology workforce, including radiation oncologists, residents, medical dosimetrists, radiation therapists, medical physicists, nurse practitioners, nurses, physician assistants, and practice managers/administrators. The survey was disseminated by the American Society for Radiation Oncology (ASTRO) together with specialty societies representing other workforce segments. An overview of the methods and global results is presented in this paper. Results: A total of 6765 completed surveys were received, a response rate of 19%, and the final analysis included 5257 respondents. Three-quarters of the radiation oncologists, residents, and physicists who responded were male, in contrast to the other segments in which two-thirds or more were female. The majority of respondents (58%) indicated they were hospital-based, whereas 40% practiced in a free-standing/satellite clinic and 2% in another setting. Among the practices represented in the survey, 21.5% were academic, 25.2% were hospital, and 53.3% were private. A perceived oversupply of professionals relative to demand was reported by the physicist, dosimetrist, and radiation therapist segments. An undersupply was perceived by physician's assistants, nurse practitioners, and nurses. The supply of radiation oncologists and residents was considered balanced. Conclusions: This survey was unique as it attempted to comprehensively assess the radiation oncology workforce by directly surveying each segment. The results suggest there is potential to improve the diversity of the workforce and optimize the supply of the workforce segments. The survey also provides a benchmark for

  12. Multi-frequency survey of background radiations of the Universe. The "Cosmological Gene" project. First results

    NASA Astrophysics Data System (ADS)

    Parijskij, Yu. N.; Mingaliev, M. G.; Nizhel'Skii, N. A.; Bursov, N. N.; Berlin, A. B.; Grechkin, A. A.; Zharov, V. I.; Zhekanis, G. V.; Majorova, E. K.; Semenova, T. A.; Stolyarov, V. A.; Tsybulev, P. G.; Kratov, D. V.; Udovitskii, R. Yu.; Khaikin, V. B.

    2011-10-01

    The results of the first stage of the "Cosmological Gene" project of the Russian Academy of Sciences are reported. These results consist in the accumulation of multi-frequency data in 31 frequency channels in the wavelength interval 1-55 cm with maximum achievable statistical sensitivity limited by the noise of background radio sources at all wavelengths exceeding 1.38 cm. The survey region is determined by constraints 00 h < RA < 24 h and 40°30' < DEC < 42°30'. The scientific goals of the project are refined in view of recent proposals to use cosmological background radiation data for the development of a unified physical theory. Experimental data obtained with the RATAN-600 radio telescope are used to refine the contribution of the main "screens" located between the observer and the formation epoch of cosmic background radiation ( z = 1100). Experimental data for synchrotron radiation and free-free noise on scales that are of interest for the anisotropy of cosmic microwave background are reported as well as the contribution of these noise components in millimeter-wave experiments to be performed in the nearest years. The role of dipole radio emission of fullerene-type dust nanostructures is shown to be small. The most precise estimates of the role of background radio sources with inverted spectra are given and these sources are shown to create no serious interference in experiments. The average spectral indices of the weakest sources of the NVSS and FIRST catalogs are estimated. The "saturation" data for all wavelengths allowed a constraint to be imposed on the Sunyaev-Zeldovich noise (the SZ noise) at all wavelengths, and made it possible to obtain independent estimates of the average sky temperature from sources, substantially weaker than those listed in the NVSS catalog. These estimates are inconsistent with the existence of powerful extragalactic synchrotron background associated with radio sources. Appreciable "quadrupole" anisotropy in is detected in the

  13. The anisotropic radiative transfer problem in optically thick, strongly magnetized plasma - A comparison of results

    NASA Technical Reports Server (NTRS)

    Pavlov, G. G.; Shibanov, Iu. A.; Silantev, N. A.; Nagel, W.

    1985-01-01

    The accuracy of four different methods for solving the coherent radiative transfer problem in a strongly magnetized plasma is compared. Specific attention is given to the case of a semi-infinite homogeneous plasma with a magnetic field perpendicular to the surface. The four approaches evaluated were: diffusion approximation schemes; the generalized H-function method of Silant'ev (1982) the Feautrier method of Nagel (1981) and the integral equation approach of Meszares and Bonazzola (1981). It is found that the coupled diffusion approximation schemes of Nagel (1981) and Kaminker et al. (1982) provided satisfactory results and were more efficient in many cases than direct numerical methods.

  14. RECENT RESULTS OF RADIATION HYDRODYNAMICS AND TURBULENCE EXPERIMENTS IN CYLINDRICAL GEOMETRY.

    SciTech Connect

    Magelssen G. R.; Scott, J. M.; Batha, S. H.; Holmes, R. L.; Lanier, N. E.; Tubbs, D. L.; Elliott, N. E.; Dunne, A. M.; Rothman, S.; Parker, K. W.; Youngs, D.

    2001-01-01

    Cylindrical implosion experiments at the University of Rochester laser facility, OMEGA, were performed to study radiation hydrodynamics and compressible turbulence in convergent geometry. Laser beams were used to directly drive a cylinder with either a gold (AU) or dichloropolystyrene (C6H8CL2) marker layer placed between a solid CH ablator and a foam cushion. When the cylinder is imploded the Richtmyer-Meshkov instability and convergence cause the marker layer to increase in thickness. Marker thickness measurements were made by x-ray backlighting along the cylinder axis. Experimental results of the effect of surface roughness will be presented. Computational results with an AMR code are in good agreement with the experimental results from targets with the roughest surface. Computational results suggest that marker layer 'end effects' and bowing increase the effective thickness of the marker layer at lower levels of roughness.

  15. RESULTS OF THE FIRST RUN OF THE NASA SPACE RADIATION LABORATORY AT BNL.

    SciTech Connect

    BROWN,K.A.AHRENS,L.BRENNAN,J.M.ET. AL.

    2004-07-05

    The NASA Space Radiation Laboratory (NSRL) was constructed in collaboration with NASA for the purpose of performing radiation effect studies for the NASA space program. The results of commissioning of this new facility were reported in [l]. In this report we will describe the results of the first run. The NSRL is capable of making use of heavy ions in the range of 0.05 to 3 GeV/n slow extracted from BNL's AGS Booster. Many modes of operation were explored during the first run, demonstrating all the capabilities designed into the system. Heavy ion intensities from 100 particles per pulse up to 12 x 10{sup 9} particles per pulse were delivered to a large variety of experiments, providing a dose range up to 70 Gy/min over a 5 x 5 cm{sup 2} area. Results presented will include those related to the production of beams that are highly uniform in both the transverse and longitudinal planes of motion [2].

  16. Radiation

    NASA Image and Video Library

    Outside the protective cocoon of Earth's atmosphere, the universe is full of harmful radiation. Astronauts who live and work in space are exposed not only to ultraviolet rays but also to space radi...

  17. An assessment of the current US radiation oncology workforce: methodology and global results of the American Society for Radiation Oncology 2012 Workforce Study.

    PubMed

    Vichare, Anushree; Washington, Raynard; Patton, Caroline; Arnone, Anna; Olsen, Christine; Fung, Claire Y; Hopkins, Shane; Pohar, Surjeet

    2013-12-01

    To determine the characteristics, needs, and concerns of the current radiation oncology workforce, evaluate best practices and opportunities for improving quality and safety, and assess what we can predict about the future workforce. An online survey was distributed to 35,204 respondents from all segments of the radiation oncology workforce, including radiation oncologists, residents, medical dosimetrists, radiation therapists, medical physicists, nurse practitioners, nurses, physician assistants, and practice managers/administrators. The survey was disseminated by the American Society for Radiation Oncology (ASTRO) together with specialty societies representing other workforce segments. An overview of the methods and global results is presented in this paper. A total of 6765 completed surveys were received, a response rate of 19%, and the final analysis included 5257 respondents. Three-quarters of the radiation oncologists, residents, and physicists who responded were male, in contrast to the other segments in which two-thirds or more were female. The majority of respondents (58%) indicated they were hospital-based, whereas 40% practiced in a free-standing/satellite clinic and 2% in another setting. Among the practices represented in the survey, 21.5% were academic, 25.2% were hospital, and 53.3% were private. A perceived oversupply of professionals relative to demand was reported by the physicist, dosimetrist, and radiation therapist segments. An undersupply was perceived by physician's assistants, nurse practitioners, and nurses. The supply of radiation oncologists and residents was considered balanced. This survey was unique as it attempted to comprehensively assess the radiation oncology workforce by directly surveying each segment. The results suggest there is potential to improve the diversity of the workforce and optimize the supply of the workforce segments. The survey also provides a benchmark for future studies, as many changes in the healthcare field

  18. NASA/GEWEX Surface Radiation Budget: First Results From The Release 4 GEWEX Integrated Data Products

    NASA Astrophysics Data System (ADS)

    Stackhouse, Paul; Cox, Stephen; Gupta, Shashi; Mikovitz, J. Colleen; zhang, taiping

    2016-04-01

    The NASA/GEWEX Surface Radiation Budget (SRB) project produces shortwave and longwave surface and top of atmosphere radiative fluxes for the 1983-near present time period. Spatial resolution is 1 degree. The current release 3 (available at gewex-srb.larc.nasa.gov) uses the International Satellite Cloud Climatology Project (ISCCP) DX product for pixel level radiance and cloud information. This product is subsampled to 30 km. ISCCP is currently recalibrating and recomputing their entire data series, to be released as the H product, at 10km resolution. The ninefold increase in pixel number should help improve the RMS of the existing products and allow for future higher resolution SRB gridded product (e.g. 0.5 degree). In addition to the input data improvements, several important algorithm improvements have been made. Most notable has been the adaptation of Angular Distribution Models (ADMs) from CERES to improve the initial calculation of shortwave TOA fluxes, from which the surface flux calculations follow. Other key input improvements include a detailed aerosol history using the Max Planck Institut Aerosol Climatology (MAC), temperature and moisture profiles from HIRS, and new topography, surface type, and snow/ice. Here we present results for the improved GEWEX Shortwave and Longwave algorithm (GSW and GLW) with new ISCCP data, the various other improved input data sets and the incorporation of many additional internal SRB model improvements. As of the time of abstract submission, results from 2007 have been produced with ISCCP H availability the limiting factor. More SRB data will be produced as ISCCP reprocessing continues. The SRB data produced will be released as part of the Release 4.0 Integrated Product, recognizing the interdependence of the radiative fluxes with other GEWEX products providing estimates of the Earth's global water and energy cycle (I.e., ISCCP, SeaFlux, LandFlux, NVAP, etc.).

  19. Radiative Forcing associated with Particulate Carbon Emissions resulting from the Use of Mercury Control Technology

    NASA Astrophysics Data System (ADS)

    Clack, H.; Penner, J. E.; Lin, G.

    2013-12-01

    Mercury is a persistent, toxic metal that bio-accumulates within the food web and causes neurological damage and fetal defects in humans. The U.S. was the first country to regulate the leading anthropogenic source of mercury into the atmosphere: coal combustion for electric power generation. The U.S. EPA's 2005 Clean Air Mercury Rule (CAMR) was replaced and further tightened in 2012 by the Mercury and Air Toxics Standard (MATS), which required existing coal-fired utilities to reduce their mercury emissions by approximately 90% by 2015. Outside the U.S., the Governing Council of the United Nations Environment Programme (UNEP) has passed the legally binding Minamata global mercury treaty that compels its signatory countries to prevent and reduce the emission and release of mercury. The most mature technology for controlling mercury emissions from coal combustion is the injection into the flue gas of powdered activated carbon (PAC) adsorbents having chemically treated surfaces designed to rapidly oxidize and adsorb mercury. However, such PAC is known to have electrical properties that make it difficult to remove from flue gas via electrostatic precipitation, by far the most common particulate control technology used in countries such as the U.S., India, and China which rely heavily on coal for power generation. As a result, PAC used to control mercury emissions can be emitted into the atmosphere, the sub-micron fraction of which may result in unintended radiative forcing similar to black carbon (BC). Here, we estimate the potential increases in secondary BC emissions, those not produced from combustion but arising instead from the use of injected PAC for mercury emission reduction. We also calculate the radiative forcing associated with these secondary BC emissions by using a global atmospheric chemical transport model coupled with a radiative transfer model.

  20. Transmission of infectious diseases en route to habitat hotspots.

    PubMed

    Benavides, Julio; Walsh, Peter D; Meyers, Lauren Ancel; Raymond, Michel; Caillaud, Damien

    2012-01-01

    The spread of infectious diseases in wildlife populations is influenced by patterns of between-host contacts. Habitat "hotspots"--places attracting a large numbers of individuals or social groups--can significantly alter contact patterns and, hence, disease propagation. Research on the importance of habitat hotspots in wildlife epidemiology has primarily focused on how inter-individual contacts occurring at the hotspot itself increase disease transmission. However, in territorial animals, epidemiologically important contacts may primarily occur as animals cross through territories of conspecifics en route to habitat hotspots. So far, the phenomenon has received little attention. Here, we investigate the importance of these contacts in the case where infectious individuals keep visiting the hotspots and in the case where these individuals are not able to travel to the hotspot any more. We developed a simulation epidemiological model to investigate both cases in a scenario when transmission at the hotspot does not occur. We find that (i) hotspots still exacerbate epidemics, (ii) when infectious individuals do not travel to the hotspot, the most vulnerable individuals are those residing at intermediate distances from the hotspot rather than nearby, and (iii) the epidemiological vulnerability of a population is the highest when the number of hotspots is intermediate. By altering animal movements in their vicinity, habitat hotspots can thus strongly increase the spread of infectious diseases, even when disease transmission does not occur at the hotspot itself. Interestingly, when animals only visit the nearest hotspot, creating additional artificial hotspots, rather than reducing their number, may be an efficient disease control measure.

  1. Evidence that the maximum electron energy in hotspots of FR II galaxies is not determined by synchrotron cooling

    NASA Astrophysics Data System (ADS)

    Araudo, Anabella T.; Bell, Anthony R.; Crilly, Aidan; Blundell, Katherine M.

    2016-08-01

    It has been suggested that relativistic shocks in extragalactic sources may accelerate the highest energy cosmic rays. The maximum energy to which cosmic rays can be accelerated depends on the structure of magnetic turbulence near the shock but recent theoretical advances indicate that relativistic shocks are probably unable to accelerate particles to energies much larger than a PeV. We study the hotspots of powerful radiogalaxies, where electrons accelerated at the termination shock emit synchrotron radiation. The turnover of the synchrotron spectrum is typically observed between infrared and optical frequencies, indicating that the maximum energy of non-thermal electrons accelerated at the shock is ≲ TeV for a canonical magnetic field of ˜100 μG. Based on theoretical considerations we show that this maximum energy cannot be constrained by synchrotron losses as usually assumed, unless the jet density is unreasonably large and most of the jet upstream energy goes to non-thermal particles. We test this result by considering a sample of hotspots observed with high spatial resolution at radio, infrared and optical wavelengths.

  2. Juniper Pollen Hotspots in the Southwest

    NASA Technical Reports Server (NTRS)

    Bunderson, L. D.; VandeWater, P.; Luvall, J.; Levetin, E.

    2013-01-01

    Rationale: Juniperus pollen is a major allergen in Texas, Oklahoma, and New Mexico. While the bulk of pollen may be released in rural areas, large amounts of pollen can be transported to urban areas. Major juniper species in the region include: Juniperus ashei, J. virginiana, J. pinchotii, and J. monosperma. Pollen release is virtually continuous beginning in late September with J. pinchotii and ending in May with J. monosperma. Urban areas in the region were evaluated for the potential of overlapping seasons in order to inform sensitive individuals. Methods: Burkard volumetric pollen traps were established for two consecutive spring seasons at 6 sites in northern New Mexico and 6 sites for two consecutive winter and fall seasons in Texas and Oklahoma Standard methods were used in the preparation and analysis of slides. Results: The Dallas-Fort Worth Metroplex is home to over 6 million people. It is adjacent to populations of J. pinchotii, J. virginiana, and J. ashei. Peak concentration near Dallas for J. ashei in 2011 was 5891 pollen grains/m3 in January 7th. The peak date for J. pinchotii at an upwind sampling location in San Marcos, TX was November 1, 2010 and peak for J. virginiana at a nearby station in Tulsa, OK was November 1, 2010 and peak for J. virginiana at a nearby station in Tulsa, OK was February 20, 2011. Amarillo, TX is adjacent to J. pinchotii, J. ashei, and J. monosperma populations and may be subject to juniper pollen from September through May. Conclusions: Considering the overlapping distributions of juniper trees and the overlapping temporal release of pollen, sensitive patients may benefit from avoiding hotspots.

  3. Cancer research results of the consortial radiation team of the NSBRI

    NASA Astrophysics Data System (ADS)

    Dicello, J. F.; Chang, P. Y.; Huso, D. L.; Kennedy, A. R.

    During the last eight years through a cooperative agreement with NASA, the National Space Biomedical Research Institute (NSBRI) has been investigating biological risks for personnel in Space, biologic mechanisms and environmental factors responsible for those risks, and countermeasures that could reduce the consequences. The NSBRI uses a programmatic approach where each major risk is investigated by a team through a consortium of individual peer-reviewed research grants. In its initial structuring, NSBRI recognized radiation as one of the major risks in Space, and the Radiation Team has been investigating radiation-induced excess cancer incidences, damage to the central nervous system, and other non-malignant diseases. This presentation reports cancer results and underlying mechanisms. The team is completing the first comprehensive measurement of cancers induced by protons or energetic heavy ions (HZEs) in rodent models (J. Dicello). The results for breast cancer suggest that the biological effectiveness of particles such as iron ions may be less than that frequently assumed. The Team has further demonstrated that exposures to such particles at levels comparable to those in space might be mitigated through pharmaceutical intervention even after exposures have occurred (D. Huso). Dr. Huso's group was able to identify through genetic marking with quantitative immunohistochemistry and microarray analysis that resistant, poorly differentiated breast cancers appear to arise from epithelial cells with a unique gene expression profile. In a parallel NIH grant, Dr. D. Huso developed a new transgenic mouse model for NSBRI studies that better parallels specific genetic pathways associated with hematopoietic malignancies. Dr. A. Kennedy's group at the University of Pennsylvania has shown that non-toxic nutritional supplements can decrease the cytotoxicity levels of oxidative stress and yields of malignantly transformed cells induced by the types of radiation encountered

  4. Hypofractionated stereotactic radiation therapy for skull base and upper cervical chordoma and chondrosarcoma: preliminary results.

    PubMed

    Gwak, Ho-Shin; Yoo, Hyung-Jun; Youn, Sang-Min; Chang, Ungkyu; Lee, Dong Han; Yoo, Seong-Yul; Rhee, Chang Hun

    2005-01-01

    Chordoma and chondrosarcoma are rare tumors of the base of the skull and are difficult candidates for surgical treatment. They are also usually resistant to conventional radiation therapy. We report preliminary results of hypofractionated stereotactic radiation therapy (SRT) using the Cyberknife system (Accuray Inc., Sunnyvale, Calif., USA) for primary and recurrent chordomas and chondrosarcomas of the skull base and upper cervical region. Nine pathologically proven chordoma/chondrosarcoma patients underwent Cyberknife treatment, and in 4 patients Cyberknife was performed as a primary adjuvant treatment after operation. Remainder of the patients had previously received conventional radiotherapy except 1 who had received Gamma Knife treatment. The prescribed tumor dose ranged from 21 to 43.6 Gy in three to five fractions. The dosimetric characteristics were evaluated for conformity and coverage indices. Dose volume histograms of both the tumor and the critical structure were obtained, and the dose delivered to a specific volume (25, 50 and 100%) of the critical structure was calculated in each case. Mass response was measured on follow-up MRI scans. Total tumor doses of different fractionation numbers were converted into single session equivalent doses and linear quadratic equivalent doses of conventional radiation for comparison among patient groups. No significant complications were observed during the treatment and early follow-up periods except one instance of transient esophagitis and one instance of otitis. All treatment plans met the criteria for standard protocol of radiosurgery suggested by the Radiation Therapy Oncology Group, specifically in terms of conformity index, which ranged from 1.01 to 1.83. Three plans had a coverage index that was rated as a minor acceptable deviation. All patients were followed from 11 to 30 (median 24) months following the treatment with regular magnetic resonance images, and 4 patients showed mass reduction. Disease

  5. Preliminary Results from an Investigation into Nanostructured Nuclear Radiation Detectors for Non-Proliferation Applications

    SciTech Connect

    ,

    2012-10-01

    In recent years, the concept of embedding composite scintillators consisting of nanosized inorganic crystals in an organic matrix has been actively pursued. Nanocomposite detectors have the potential to meet many of the homeland security, non-proliferation, and border and cargo-screening needs of the nation and, by virtue of their superior nuclear identification capability over plastic, at roughly the same cost as plastic, have the potential to replace all plastic detectors. Nanocomposites clearly have the potential of being a gamma ray detection material that would be sensitive yet less expensive and easier to produce on a large scale than growing large, whole crystals of similar sensitivity. These detectors would have a broad energy range and a sufficient energy resolution to perform isotopic identification. The material can also be fabricated on an industrial scale, further reducing cost. This investigation focused on designing and fabricating prototype core/shell and quantum dot (QD) detectors. Fourteen core/shell and four QD detectors, all with the basic consistency of a mixture of nanoparticles in a polymer matrix with different densities of nanoparticles, were prepared. Nanoparticles with sizes <10 nm were fabricated, embedded in a polystyrene matrix, and the resultant scintillators’ radiation detector properties were characterized. This work also attempted to extend the gamma energy response on both low- and high-energy regimes by demonstrating the ability to detect low-energy and high-energy gamma rays. Preliminary results of this investigation are consistent with a significant response of these materials to nuclear radiation.

  6. Aircrew Exposure To Cosmic Radiation Evaluated By Means Of Several Methods; Results Obtained In 2006

    SciTech Connect

    Ploc, Ondrej; Spurny, Frantisek; Jadrnickova, Iva; Turek, Karel

    2008-08-07

    Routine evaluation of aircraft crew exposure to cosmic radiation in the Czech Republic is performed by means of calculation method. Measurements onboard aircraft work as a control tool of the routine method, as well as a possibility of comparison of results measured by means of several methods. The following methods were used in 2006: (1) mobile dosimetry unit (MDU) type Liulin--a spectrometer of energy deposited in Si-detector; (2) two types of LET spectrometers based on the chemically etched track detectors (TED); (3) two types of thermoluminescent detectors; and (4) two calculation methods. MDU represents currently one of the most reliable equipments for evaluation of the aircraft crew exposure to cosmic radiation. It is an active device which measures total energy depositions (E{sub dep}) in the semiconductor unit, and, after appropriate calibration, is able to give a separate estimation for non-neutron and neutron-like components of H*(10). This contribution consists mostly of results acquired by means of this equipment; measurements with passive detectors and calculations are mentioned because of comparison. Reasonably good agreement of all data sets could be stated.

  7. 193-nm radiation durability study of MoSi binary mask and resulting lithographic performance

    NASA Astrophysics Data System (ADS)

    Servin, Isabelle; Belledent, Jérôme; Pain, Laurent; Connolly, Brid; Sczyrba, Martin; Lamantia, Matt

    2011-05-01

    Dimensions on mask continue to shrink to keep up with the ITRS roadmap. This has implications on the material of choice for the blanks. For example, the new binary OMOG stack (Opaque MOSi on Glass) was successfully introduced to meet the mask specifications at the 32nm technology node. Obviously 193-nm optical lithography will be further used in production at even higher NA and lower k1 emphasizing, for example, the impact on wafer of any electromagnetic field migration effects. Indeed, long term radiation damage inducing CD growth and consequently, device yield loss, has already been reported [1, 2]. This mechanism, known as Electric Field induced Migration of chrome (EMF) often shortens the mask's lifetime. Here, a study was conducted to investigate the impact of intensive ArF scanner exposure both on final wafer and mask performances. The Si printed wafers measured with top-down CD-SEM were characterized with respect to CD uniformity, linearity, Sub Resolution Assist Feature (SRAF) printability through process window, MEEF, DOF, and OPC accuracy. The data was also correlated to advanced mask inspection results (e.g. AIMSTM) taken at the same location. More precisely, this work follows a preliminary study [1] which pointed out that OMOG is less sensitive to radiation than standard COG (Chrome On Glass). And, in this paper, we report on results obtained at higher energy to determine the ultimate lifetime of OMOG masks.

  8. Results of Simulated Galactic Cosmic Radiation (GCR) and Solar Particle Events (SPE) on Spectra Restraint Fabric

    NASA Technical Reports Server (NTRS)

    Peters, Benjamin; Hussain, Sarosh; Waller, Jess

    2017-01-01

    Spectra or similar Ultra-high-molecular-weight polyethylene (UHMWPE) fabric is the likely choice for future structural space suit restraint materials due to its high strength-to-weight ratio, abrasion resistance, and dimensional stability. During long duration space missions, space suits will be subjected to significant amounts of high-energy radiation from several different sources. To insure that pressure garment designs properly account for effects of radiation, it is important to characterize the mechanical changes to structural materials after they have been irradiated. White Sands Test Facility (WSFTF) collaborated with the Crew and Thermal Systems Division at the Johnson Space Center (JSC) to irradiate and test various space suit materials by examining their tensile properties through blunt probe puncture testing and single fiber tensile testing after the materials had been dosed at various levels of simulated GCR and SPE Iron and Proton beams at Brookhaven National Laboratories. The dosages were chosen based on a simulation developed by the Structural Engineering Division at JSC for the expected radiation dosages seen by space suit softgoods seen on a Mars reference mission. Spectra fabric tested in the effort saw equivalent dosages at 2x, 10x, and 20x the predicted dose as well as a simulated 50 year exposure to examine the range of effects on the material and examine whether any degradation due to GCR would be present if the suit softgoods were stored in deep space for a long period of time. This paper presents the results of this work and outlines the impact on space suit pressure garment design for long duration deep space missions.

  9. The Aurora radiation-hydrodynamical simulations of reionization: calibration and first results

    NASA Astrophysics Data System (ADS)

    Pawlik, Andreas H.; Rahmati, Alireza; Schaye, Joop; Jeon, Myoungwon; Dalla Vecchia, Claudio

    2017-04-01

    We introduce a new suite of radiation-hydrodynamical simulations of galaxy formation and reionization called Aurora. The Aurora simulations make use of a spatially adaptive radiative transfer technique that lets us accurately capture the small-scale structure in the gas at the resolution of the hydrodynamics, in cosmological volumes. In addition to ionizing radiation, Aurora includes galactic winds driven by star formation and the enrichment of the universe with metals synthesized in the stars. Our reference simulation uses 2 × 5123 dark matter and gas particles in a box of size 25 h-1 comoving Mpc with a force softening scale of at most 0.28 h-1 kpc. It is accompanied by simulations in larger and smaller boxes and at higher and lower resolution, employing up to 2 × 10243 particles, to investigate numerical convergence. All simulations are calibrated to yield simulated star formation rate functions in close agreement with observational constraints at redshift z = 7 and to achieve reionization at z ≈ 8.3, which is consistent with the observed optical depth to reionization. We focus on the design and calibration of the simulations and present some first results. The median stellar metallicities of low-mass galaxies at z = 6 are consistent with the metallicities of dwarf galaxies in the Local Group, which are believed to have formed most of their stars at high redshifts. After reionization, the mean photoionization rate decreases systematically with increasing resolution. This coincides with a systematic increase in the abundance of neutral hydrogen absorbers in the intergalactic medium.

  10. Educating medical students about radiation oncology: initial results of the oncology education initiative.

    PubMed

    Hirsch, Ariel E; Singh, Deeptej; Ozonoff, Al; Slanetz, Priscilla J

    2007-10-01

    Multidisciplinary cancer care requires the integration of teaching across established educational boundaries. Because exposure to oncology and radiation oncology is limited in the undergraduate medical curriculum, the authors introduced an oncology education initiative at their institution. They report on the addition of structured multidisciplinary oncology education to the required radiology core clerkship. An institutional-based cohort study of fourth-year medical students rotating through a required clerkship in radiology at Boston University School of Medicine was conducted, beginning with the class of 2007. An educational questionnaire measuring the perceived quality of oncology education before and after exposure to a structured didactic program was administered. Of the 149 fourth-year students, 121 (81%) have completed the didactics of the initiative. Although 68 of 121 (56%) students reported having limited exposure to cancer care in the clinical years, 107 of 121 (88%) were motivated to learn more about the subject, and 100 of 121 (83%) reported a better understanding of the multidisciplinary nature of cancer care after this oncology education initiative. One hundred ten of 121 (91%) felt that the radiology clerkship was an opportune time to receive oncology and radiation oncology teaching. As a result of the initiative, 32% of the students pursued advanced training in radiation oncology. Of students who before the initiative were not planning on taking oncology electives, 70 of 99 (71%) agreed or strongly agreed that the lecture motivated them to learn more about the subject, and 43 of 99 (43%) agreed or strongly agreed that the lecture motivated them to take oncology electives. Systematic exposure to multidisciplinary oncology education as part of a radiology core clerkship provides an excellent opportunity for the integrated teaching of oncologic principles and patient management. This type of experience addresses an important yet underrepresented

  11. Aerosol radiative forcing controls: Results from an Indian table-top mining region

    NASA Astrophysics Data System (ADS)

    Latha, R.; Murthy, B. S.; Kumar, Manoj; Lipi, K.; Jyotsna, S.

    2013-12-01

    Aerosol radiative forcing (ARF) over intense mining area in Indian monsoon trough region, computed based on the aerosol optical properties obtained through Prede (POM-1L) sky radiometer and radiative transfer model, are analysed for the year 2011 based on 21 clear sky days spread through seasons. Due to active mining and varied minerals ARF is expected to be significantly modulated by single scattering albedo (SSA). Our studies show that radiative forcing normalized by aerosol optical depth (AOD) is highly correlated with SSA (0.96) while ARF at the surface with AOD by 0.92. Our results indicate that for a given AOD, limits or range of ARF are determined by SSA, hence endorses the need to obtain SSA accurately, preferably derived through observations concurrent with AOD. Noticeably, ARF at the top-of the atmosphere is well connected to SSA (r = 0.77) than AOD (r = 0.6). Relation between observed black carbon and SSA are investigated. A possible over estimation of SSA by the inversion algorithm, SKYRAD.pack 4.2, used in the current study is also discussed. Choice of atmospheric profiles deviating from tropical to mid altitude summer or winter does not appear to be sensitive in ARF calculation by SBDART. Based on the 21 clear sky days, a multiple linear regression equation is obtained for ARFbot as a function of AOD and SSA with a bias of ±2.7 Wm-2. This equation is verified with an independent data set of seasonal mean AOD and SSA to calculate seasonal ARF that compares well with the modeled ARF within ±4 Wm-2.

  12. Automated hotspot analysis with aerial image CD metrology for advanced logic devices

    NASA Astrophysics Data System (ADS)

    Buttgereit, Ute; Trautzsch, Thomas; Kim, Min-ho; Seo, Jung-Uk; Yoon, Young-Keun; Han, Hak-Seung; Chung, Dong Hoon; Jeon, Chan-Uk; Meyers, Gary

    2014-09-01

    Continuously shrinking designs by further extension of 193nm technology lead to a much higher probability of hotspots especially for the manufacturing of advanced logic devices. The CD of these potential hotspots needs to be precisely controlled and measured on the mask. On top of that, the feature complexity increases due to high OPC load in the logic mask design which is an additional challenge for CD metrology. Therefore the hotspot measurements have been performed on WLCD from ZEISS, which provides the benefit of reduced complexity by measuring the CD in the aerial image and qualifying the printing relevant CD. This is especially of advantage for complex 2D feature measurements. Additionally, the data preparation for CD measurement becomes more critical due to the larger amount of CD measurements and the increasing feature diversity. For the data preparation this means to identify these hotspots and mark them automatically with the correct marker required to make the feature specific CD measurement successful. Currently available methods can address generic pattern but cannot deal with the pattern diversity of the hotspots. The paper will explore a method how to overcome those limitations and to enhance the time-to-result in the marking process dramatically. For the marking process the Synopsys WLCD Output Module was utilized, which is an interface between the CATS mask data prep software and the WLCD metrology tool. It translates the CATS marking directly into an executable WLCD measurement job including CD analysis. The paper will describe the utilized method and flow for the hotspot measurement. Additionally, the achieved results on hotspot measurements utilizing this method will be presented.

  13. Analysis of the segmentation and influence of hotspots along the southern Atlantic conjugate margins

    NASA Astrophysics Data System (ADS)

    Briais, A.; Lin, J.

    2003-04-01

    The aim of our analysis is to assess the role of mantle temperature anomalies in the structure of continental margins. We analyze the longitudinal variations of the crustal structure of the southern Atlantic continental margins to investigate the segmented character of the margins and the impact of the hotspots at the time of opening. We use free-air gravity anomalies derived from satellite altimetry measurements, and bathymetry compilation to estimate mantle Bouguer anomalies in the oceanic part and isostatic gravity anomalies along the margins. The two conjugate margins display similar patterns of gravity anomalies. The structure of the South Atlantic margins is disrupted near 20°S at their intersection with the Walvis ridge on the African margin and the Rio Grande rise on the South American side, which result from the interaction of the Tristan da Cunha hotspot with the South Atlantic rift and with the Southern Mid-Atlantic Ridge. The hotspot generated huge volumes of flood basalts on the Paraná volcanic traps on the South American plate, and the Etendeka volcanic province on the African plate. At the time of breakup near 140 Ma, the hotspot was located just beneath the rift. The whole section of the South Atlantic margin south of the Walvis ridge was affected by that hotspot, representing a length of more than 1200 km. This result confirms the observation of seaward-dipping reflectors on seismic profiles in this section. Variations at intermediate wavelength of 400-600 km are also observed within this section. Farther north, the St. Helena hotspot had a much more moderate effect both on the continents and on the margins, affecting only about 200 km of the African margin. The section of margin not directly affected by hotspots displays along-margin variations at intermediate wavelengths of 200 to 500 km. The gravity study will be complemented by an analysis of the magnetic anomalies.

  14. Hotspot Cooling with Self-Propelled Jumping Condensate

    NASA Astrophysics Data System (ADS)

    Qu, Xiaopeng; Boreyko, Jonathan B.; Liu, Fangjie; Chen, Chuan-Hua

    2012-11-01

    Dynamic hotspots are prevalent in electronic systems including microprocessors and power electronics with constantly changing computing tasks or payloads. Here, we report a new adaptive hotspot cooling technique that rapidly responds to moving hotspots in a passive manner independent of external forces. The hotspot cooling is based upon the self-propelled jumping of dropwise condensate, which directly returns the working fluid from a superhydrophobic condenser to an opposing superhydrophilic evaporator. The adaptive thermal management is accomplished by the preferential evaporation of water at the hotspots and the rapid jumping return of the condensate across the very short inter-plate distance. The proof-of-concept for this hotspot cooling technique will be demonstrated by the adaptive response to hotspots at increasing heat fluxes. Corresponding author.

  15. Continuous representation of tumor microvessel density and detection of angiogenic hotspots in histological whole-slide images

    PubMed Central

    Kather, Jakob Nikolas; Marx, Alexander; Reyes-Aldasoro, Constantino Carlos; Schad, Lothar R.; Zöllner, Frank Gerrit; Weis, Cleo-Aron

    2015-01-01

    Blood vessels in solid tumors are not randomly distributed, but are clustered in angiogenic hotspots. Tumor microvessel density (MVD) within these hotspots correlates with patient survival and is widely used both in diagnostic routine and in clinical trials. Still, these hotspots are usually subjectively defined. There is no unbiased, continuous and explicit representation of tumor vessel distribution in histological whole slide images. This shortcoming distorts angiogenesis measurements and may account for ambiguous results in the literature. In the present study, we describe and evaluate a new method that eliminates this bias and makes angiogenesis quantification more objective and more efficient. Our approach involves automatic slide scanning, automatic image analysis and spatial statistical analysis. By comparing a continuous MVD function of the actual sample to random point patterns, we introduce an objective criterion for hotspot detection: An angiogenic hotspot is defined as a clustering of blood vessels that is very unlikely to occur randomly. We evaluate the proposed method in N=11 images of human colorectal carcinoma samples and compare the results to a blinded human observer. For the first time, we demonstrate the existence of statistically significant hotspots in tumor images and provide a tool to accurately detect these hotspots. PMID:26061817

  16. Disaster waste characteristics and radiation distribution as a result of the Great East Japan Earthquake.

    PubMed

    Shibata, Tomoyuki; Solo-Gabriele, Helena; Hata, Toshimitsu

    2012-04-03

    The compounded impacts of the catastrophes that resulted from the Great East Japan Earthquake have emphasized the need to develop strategies to respond to multiple types and sources of contamination. In Japan, earthquake and tsunami-generated waste were found to have elevated levels of metals/metalloids (e.g., mercury, arsenic, and lead) with separation and sorting more difficult for tsunami-generated waste as opposed to earthquake-generated waste. Radiation contamination superimposed on these disaster wastes has made it particularly difficult to manage the ultimate disposal resulting in delays in waste management. Work is needed to develop policies a priori for handling wastes from combined catastrophes such as those recently observed in Japan.

  17. Continuous electromagnetic radiation monitoring in the environment: analysis of the results in Greece.

    PubMed

    Manassas, Athanasios; Boursianis, Achilles; Samaras, Theodoros; Sahalos, John N

    2012-09-01

    Non-ionising radiation-monitoring networks were initiated as a result of the public concerns about the potential health effects from telecommunication emissions. In the present study, the data acquired from such networks in Greece are used to assess the changes in the outdoor electromagnetic environment with respect to location and time. The study shows that there is a statistically significant difference between the urban (median electric field: 1.1 V m(-1)) and the rural (median electric field: 0.3 V m(-1)) installations of monitoring units and also shows that there is a median diurnal variation (daily maximum to minimum) of 20.2 and 33.8 % for the broadcasting and mobile telecommunication emissions, respectively. Moreover, there is a difference in the electric field between daytime and night, but not between morning and afternoon. The results are in line with previously published data from spot measurements, monitoring networks and personal exposimeter studies performed in several European countries.

  18. Latest results on solarization of optical glasses with pulsed laser radiation

    NASA Astrophysics Data System (ADS)

    Jedamzik, Ralf; Petzold, Uwe

    2017-02-01

    Femtosecond lasers are more and more used for material processing and lithography. Femtosecond laser help to generate three dimensional structures in photoresists without using masks in micro lithography. This technology is of growing importance for the field of backend lithography or advanced packaging. Optical glasses used for beam shaping and inspection tools need to withstand high laser pulse energies. Femtosecond laser radiation in the near UV wavelength range generates solarization effects in optical glasses. In this paper results are shown of femtosecond laser solarization experiments on a broad range of optical glasses from SCHOTT. The measurements have been performed by the Laser Zentrum Hannover in Germany. The results and their impact are discussed in comparison to traditional HOK-4 and UVA-B solarization measurements of the same materials. The target is to provide material selection guidance to the optical designer of beam shaping lens systems.

  19. Initial Results on an Approach for Creating Tunable UV Radiation for Spectroscopy at 243nm

    NASA Astrophysics Data System (ADS)

    Khademian, Ali; Shiner, David

    2004-05-01

    Convenient tunable coherent UV radiation could be used in number of atomic physics applications. Our particular interest is in a 243nm laser that can be used to precisely measure the 1S to 2S interval in atomic tritium. An approach is being investigated which might ultimately be less cumbersome and expensive than current methods. A multi longitudinal mode "980nm" pump module is converted to a single longitudinal mode laser using costume fiber Bragg grating. Results for the short term frequency stability will be given. A first doubling stage using PPMgO:LN waveguide has been investigated and experimental results will be discussed. A second stage of doubling, using CLBO, which we calculated to have a better conversion efficiency than well known BBO crystal, is planned. Theoretical calculation for this stage and comparison with BBO will be presented.

  20. New results for reaction rate of the proton radiative capture on 3H

    NASA Astrophysics Data System (ADS)

    Dubovichenko, S. B.; Dzhazairov-Kakhramanov, A. V.; Afanasyeva, N. V.

    2017-07-01

    Calculations of the reaction rate of the proton radiative capture on 3H at temperatures from 0.01 T9 up to 5 T9, which are based on the theoretical results for the astrophysical S-factor and take into account the latest experimental data, were carried out. Theoretical results for the S-factor at energies from 1 keV up to 5 MeV were obtained in the framework of the modified potential cluster model with the classification of orbital states according to Young tableaux. On the basis of used nuclear model of the interaction of p and 3H particles there was shown possibility of description the latest experimental data for the S-factor at the energy range from 50 keV up to 5 MeV.

  1. Radiation Therapy for Treatment of Pigmented Villonodular Synovitis: Results of a National Patterns of Care Study

    SciTech Connect

    Heyd, Reinhard; Micke, Oliver; Berger, Bernhard; Eich, Hans T.; Ackermann, Hanns

    2010-09-01

    Purpose: The German Cooperative Group on Radiotherapy in Benign Diseases (GCG-BD) conducted a pattern-of-care study (PCS) to analyze the radiation therapy (RT) practice for pigmented villonodular synovitis (PVNS). Methods and Materials: In 2007, a structured questionnaire to assess the number of patients, the pretreatments, the RT indication, technique, target volume concepts, outcome data, and possible early or late toxicity was circulated to 227 institutions. Results: Until August 2008, a response was available from 189 institutions (83.2 %), of whom 19 (10.0 %) experienced RT for PVNS. Complete clinical information was available for 41 patients from 14 RT departments. Thirty patients (73.2 %) received postsurgical RT because of primary incomplete resection, 11 patients (26.8 %) as an adjunct after complete resections of recurrences or unclear resection status. The total doses ranged from 30 to 50 Gy (median, 36 Gy), the median single dose was 2.0 Gy. Local control was achieved 95.1%, and 82.9% had no or only slight functional impairment. The early and late toxicity was mild ({<=}RTOG Grade II). Conclusions: Radiation therapy is a safe and effective treatment for PVNS in the postoperative setting after incomplete resection, and also as a salvage option for treatment of recurrences it provides a high rate of local control.

  2. Palliation of hepatic metastases: results of the radiation therapy oncology group pilot study. [X-ray

    SciTech Connect

    Borgelt, B.B.; Gelber, R.; Brady, L.W.; Griffin, T.; Hendrickson, F.R.

    1981-05-01

    From May, 1976, to July, 1978, 20 Radiation Therapy Oncology Group (RTOG) institutions participated in a prospective, uncontrolled, non-randomized pilot study designed to gain information regarding the feasibility of hepatic irradiation for the treatment of symptomatic liver metastases. One hundred-three of 109 patients who entered were included in the present analysis. Eligible patients included those with hepatic metastases from solid, non-hematologic tumors documented by liver scan. Patients with solitary liver metastases received either 3040 rad/19 fractions or 3000 rad/15 fractions followed by an optional 2000 rad/10 fractions boost to residual disease. Nausea and/or vomiting was induced or aggravated in 16%. There were no documented cases of radiation-induced hepatitis, nephritis or pneumonitis. Improvement of liver function chemistries occurred in 40% and palpable liver mass was reduced in 49%. The results of this study indicate that rapid courses of whole liver irradiation are well-tolerated with good therapeutic benefit in patients with symptomatic liver metastases.

  3. Multifaceted diversity-area relationships reveal global hotspots of mammalian species, trait and lineage diversity

    PubMed Central

    Mazel, Florent; Guilhaumon, François; Mouquet, Nicolas; Devictor, Vincent; Gravel, Dominique; Renaud, Julien; Cianciaruso, Marcus Vinicius; Loyola, Rafael Dias; Diniz-Filho, José Alexandre Felizola; Mouillot, David; Thuiller, Wilfried

    2014-01-01

    Aim To define biome-scale hotspots of phylogenetic and functional mammalian biodiversity (PD and FD, respectively) and compare them to ‘classical’ hotspots based on species richness (SR) only. Location Global Methods SR, PD & FD were computed for 782 terrestrial ecoregions using distribution ranges of 4616 mammalian species. We used a set of comprehensive diversity indices unified by a recent framework that incorporates the species relative coverage in each ecoregion. We build large-scale multifaceted diversity-area relationships to rank ecoregions according to their levels of biodiversity while accounting for the effect of area on each diversity facet. Finally we defined hotspots as the top-ranked ecoregions. Results While ignoring species relative coverage led to a relative good congruence between biome top ranked SR, PD and FD hotspots, ecoregions harboring a rich and abundantly represented evolutionary history and functional diversity did not match with top ranked ecoregions defined by species richness. More importantly PD and FD hotspots showed important spatial mismatches. We also found that FD and PD generally reached their maximum values faster than species richness as a function of area. Main conclusions The fact that PD/FD reach faster their maximal value than SR may suggest that the two former facets might be less vulnerable to habitat loss than the latter. While this point is expected, it is the first time that it is quantified at global scale and should have important consequences in conservation. Incorporating species relative coverage into the delineation of multifaceted hotspots of diversity lead to weak congruence between SR, PD and FD hotspots. This means that maximizing species number may fail at preserving those nodes (in the phylogenetic or functional tree) that are relatively abundant in the ecoregion. As a consequence it may be of prime importance to adopt a multifaceted biodiversity perspective to inform conservation strategies at global

  4. Global diversity hotspots and conservation priorities for sharks.

    PubMed

    Lucifora, Luis O; García, Verónica B; Worm, Boris

    2011-05-05

    Sharks are one of the most threatened groups of marine animals, as high exploitation rates coupled with low resilience to fishing pressure have resulted in population declines worldwide. Designing conservation strategies for this group depends on basic knowledge of the geographic distribution and diversity of known species. So far, this information has been fragmented and incomplete. Here, we have synthesized the first global shark diversity pattern from a new database of published sources, including all 507 species described at present, and have identified hotspots of shark species richness, functional diversity and endemicity from these data. We have evaluated the congruence of these diversity measures and demonstrate their potential use in setting priority areas for shark conservation. Our results show that shark diversity across all species peaks on the continental shelves and at mid-latitudes (30-40 degrees N and S). Global hotspots of species richness, functional diversity and endemicity were found off Japan, Taiwan, the East and West coasts of Australia, Southeast Africa, Southeast Brazil and Southeast USA. Moreover, some areas with low to moderate species richness such as Southern Australia, Angola, North Chile and Western Continental Europe stood out as places of high functional diversity. Finally, species affected by shark finning showed different patterns of diversity, with peaks closer to the Equator and a more oceanic distribution overall. Our results show that the global pattern of shark diversity is uniquely different from land, and other well-studied marine taxa, and may provide guidance for spatial approaches to shark conservation. However, similar to terrestrial ecosystems, protected areas based on hotspots of diversity and endemism alone would provide insufficient means for safeguarding the diverse functional roles that sharks play in marine ecosystems.

  5. Global Diversity Hotspots and Conservation Priorities for Sharks

    PubMed Central

    Lucifora, Luis O.; García, Verónica B.; Worm, Boris

    2011-01-01

    Sharks are one of the most threatened groups of marine animals, as high exploitation rates coupled with low resilience to fishing pressure have resulted in population declines worldwide. Designing conservation strategies for this group depends on basic knowledge of the geographic distribution and diversity of known species. So far, this information has been fragmented and incomplete. Here, we have synthesized the first global shark diversity pattern from a new database of published sources, including all 507 species described at present, and have identified hotspots of shark species richness, functional diversity and endemicity from these data. We have evaluated the congruence of these diversity measures and demonstrate their potential use in setting priority areas for shark conservation. Our results show that shark diversity across all species peaks on the continental shelves and at mid-latitudes (30–40 degrees N and S). Global hotspots of species richness, functional diversity and endemicity were found off Japan, Taiwan, the East and West coasts of Australia, Southeast Africa, Southeast Brazil and Southeast USA. Moreover, some areas with low to moderate species richness such as Southern Australia, Angola, North Chile and Western Continental Europe stood out as places of high functional diversity. Finally, species affected by shark finning showed different patterns of diversity, with peaks closer to the Equator and a more oceanic distribution overall. Our results show that the global pattern of shark diversity is uniquely different from land, and other well-studied marine taxa, and may provide guidance for spatial approaches to shark conservation. However, similar to terrestrial ecosystems, protected areas based on hotspots of diversity and endemism alone would provide insufficient means for safeguarding the diverse functional roles that sharks play in marine ecosystems. PMID:21573162

  6. Uncovering zoonoses awareness in an emerging disease 'hotspot'.

    PubMed

    Paige, Sarah B; Malavé, Carly; Mbabazi, Edith; Mayer, Jonathan; Goldberg, Tony L

    2015-03-01

    Emerging infectious diseases from animals pose significant and increasing threats to human health; places of risk are simultaneously viewed as conservation and emerging disease 'hotspots'. The One World/One Health paradigm is an 'assemblage' discipline. Extensive research from the natural and social sciences, as well as public health have contributed to designing surveillance and response policy within the One World/One Health framework. However, little research has been undertaken that considers the lives of those who experience risk in hotspots on a daily basis. As a result, policymakers and practitioners are unable to fully comprehend the social and ecological processes that catalyze cross-species pathogen exchange. This study examined local populations' comprehension of zoonotic disease. From October 2008-May 2009 we collected data from people living on the periphery of Kibale National Park, in western Uganda. We administered a survey to 72 individuals and conducted semi-structured, in-depth interviews with 14 individuals. Results from the survey showed respondents had statistically significant awareness that transmission of diseases from animals was possible compared to those who did not think such transmission was possible (x(2) = 30.68, df = 1, p < 0.05). However, individual characteristics such as gender, occupation, location, and age were not significantly predictive of awareness. Both quantitative and qualitative data show local people are aware of zoonoses and provided biomedically accurate examples of possible infections and corresponding animal sources (e.g., worm infection from pigs and Ebola from primates). Qualitative data also revealed expectations about the role of the State in managing the prevention of zoonoses from wildlife. As a result of this research, we recommend meaningful discourse with people living at the frontlines of animal contact in emerging disease and conservation hotspots in order to develop informed and relevant zoonoses

  7. Results of the 2014 Survey of the Association of Directors of Radiation Oncology Programs (ADROP).

    PubMed

    Jani, Ashesh B; Marshall, David; Vapiwala, Neha; Davis, Sara Beth; Langer, Mark

    2015-01-01

    In 2014, the Association of Directors of Radiation Oncology Programs (ADROP) conducted an in-depth survey of program directors along several axes. We report the results of this survey and compare the major findings with those of the 2007 ADROP survey. The survey was written and approved by ADROP leadership in 2012, announced online through broadcasts throughout 2013 and early 2014, and closed in mid-2014. The results based on question groups related to (1) hours spent in activities, (2) budget and nonprogram resources, (3) physics/biology didactics, (4) mock exams/didactics/research, (5) electives, (6) students, and (7) resources/challenges were tabulated. Descriptive comparisons with the 2007 survey were performed. There was 26% participation (23/88 programs). Major areas of time commitment were faculty and site organization, maintenance, and corrections (70 hours/year) and didactics/conferences and rounds (200 hours/year). The median program director protected time was 23% (range 0%-50%). All responding programs (100%) had biology and physics courses and assigned directors, but only approximately 20% of respondents had a threshold grade in these courses for graduation. Major resources desired were templates of goals/objectives by disease site, competency evaluations by level, journal club repository, and software for contouring, oral examination preparation, grant writing, publication writing, oral presentation, and effective teaching. Major activity challenges were Accreditation Council for Graduate Medical Education external review and time commitment. Overall, the 2014 results are similar to those of the 2007 survey. The average time commitment remains considerably higher than the 10% minimum required in the current ACGME program requirements. The survey results may guide ADROP membership in centralizing some of the identified resources needed. Copyright © 2015 American Society for Radiation Oncology. Published by Elsevier Inc. All rights reserved.

  8. Use of local statistics to reveal hidden information of pollution hotspots in urban soil geochemistry

    NASA Astrophysics Data System (ADS)

    Zhang, Chaosheng

    2017-04-01

    The identification of pollution hotspots is an important approach for a better understanding of spatial distribution patterns and the exploration for their influencing factors in environmental studies. One of the most often asked questions in an environmental investigation is: Where are the pollution hotspots? This presentation explains one of the popularly used methodologies called local index of spatial association (LISA) and its applications in urban geochemical studies in Galway, Ireland and London of the UK. The LISA is a useful tool for identifying pollution hotspots and classifying them into spatial clusters and spatial outliers. The results were affected by the definition of weight function, data transformation and existence of extreme values, and it is suggested that all these influencing factors should be considered until reasonable and reliable results are obtained. This method has been applied to identify Pb pollution in Galway, polluted areas in bonfires sites, elevated P and REE concentrations in London. Hotspots in identified in urban soils are related to locations of high road density, traditional festival bonfires, industries and other human activities. The results of hotspots analysis provide useful information for the management of urban soils.

  9. Partial Breast Radiation Therapy With Proton Beam: 5-Year Results With Cosmetic Outcomes

    SciTech Connect

    Bush, David A.; Do, Sharon; Lum, Sharon; Garberoglio, Carlos; Mirshahidi, Hamid; Patyal, Baldev; Grove, Roger; Slater, Jerry D.

    2014-11-01

    Purpose: We updated our previous report of a phase 2 trial using proton beam radiation therapy to deliver partial breast irradiation (PBI) in patients with early stage breast cancer. Methods and Materials: Eligible subjects had invasive nonlobular carcinoma with a maximal dimension of 3 cm. Patients underwent partial mastectomy with negative margins; axillary lymph nodes were negative on sampling. Subjects received postoperative proton beam radiation therapy to the surgical bed. The dose delivered was 40 Gy in 10 fractions, once daily over 2 weeks. Multiple fields were treated daily, and skin-sparing techniques were used. Following treatment, patients were evaluated with clinical assessments and annual mammograms to monitor toxicity, tumor recurrence, and cosmesis. Results: One hundred subjects were enrolled and treated. All patients completed the assigned treatment and were available for post-treatment analysis. The median follow-up was 60 months. Patients had a mean age of 63 years; 90% had ductal histology; the average tumor size was 1.3 cm. Actuarial data at 5 years included ipsilateral breast tumor recurrence-free survival of 97% (95% confidence interval: 100%-93%); disease-free survival of 94%; and overall survival of 95%. There were no cases of grade 3 or higher acute skin reactions, and late skin reactions included 7 cases of grade 1 telangiectasia. Patient- and physician-reported cosmesis was good to excellent in 90% of responses, was not changed from baseline measurements, and was well maintained throughout the entire 5-year follow-up period. Conclusions: Proton beam radiation therapy for PBI produced excellent ipsilateral breast recurrence-free survival with minimal toxicity. The treatment proved to be adaptable to all breast sizes and lumpectomy cavity configurations. Cosmetic results appear to be excellent and unchanged from baseline out to 5 years following treatment. Cosmetic results may be improved over those reported with photon

  10. Chromatin Folding, Fragile Sites, and Chromosome Aberrations Induced by Low- and High- LET Radiation

    NASA Technical Reports Server (NTRS)

    Zhang, Ye; Cox, Bradley; Asaithamby, Aroumougame; Chen, David J.; Wu, Honglu

    2013-01-01

    We previously demonstrated non-random distributions of breaks involved in chromosome aberrations induced by low- and high-LET radiation. To investigate the factors contributing to the break point distribution in radiation-induced chromosome aberrations, human epithelial cells were fixed in G1 phase. Interphase chromosomes were hybridized with a multicolor banding in situ hybridization (mBAND) probe for chromosome 3 which distinguishes six regions of the chromosome in separate colors. After the images were captured with a laser scanning confocal microscope, the 3-dimensional structure of interphase chromosome 3 was reconstructed at multimega base pair scale. Specific locations of the chromosome, in interphase, were also analyzed with bacterial artificial chromosome (BAC) probes. Both mBAND and BAC studies revealed non-random folding of chromatin in interphase, and suggested association of interphase chromatin folding to the radiation-induced chromosome aberration hotspots. We further investigated the distribution of genes, as well as the distribution of breaks found in tumor cells. Comparisons of these distributions to the radiation hotspots showed that some of the radiation hotspots coincide with the frequent breaks found in solid tumors and with the fragile sites for other environmental toxins. Our results suggest that multiple factors, including the chromatin structure and the gene distribution, can contribute to radiation-induced chromosome aberrations.

  11. Intensity Modulated Radiation Therapy for Primary Soft Tissue Sarcoma of the Extremity: Preliminary Results

    SciTech Connect

    Alektiar, Kaled M. . E-mail: alektiak@mskcc.org; Hong, Linda; Brennan, Murray F.; Della-Biancia, Cesar; Singer, Samuel

    2007-06-01

    Purpose: To report preliminary results on using intensity modulated radiation therapy (IMRT) as an adjuvant treatment in primary soft tissue sarcoma (STS) of the extremity. Methods and Materials: Between February 2002 and March 2005, 31 adult patients with primary STS of the extremity were treated with surgery and adjuvant IMRT. Tumor size was >10 cm in 74% of patients and grade was high in 77%. Preoperative IMRT was given to 7 patients (50 Gy) and postoperative IMRT (median dose, 63 Gy) was given to 24 patients. Complete gross resection including periosteal stripping or bone resection was required in 10, and neurolysis or nerve resection in 20. The margins were positive or within 1 mm in 17. Complications from surgery and radiation therapy (RT) were assessed using the Common Terminology Criteria for Adverse Events grading system. Results: Median follow-up time was 23 months. Grade 1 RT dermatitis developed in 71% of patients, Grade 2 in 16%, and Grade 3 in 10%. Infectious wound complications developed in 13% and noninfectious complications in 10%. Two patients (6.4%) developed fractures. Grade 1 neuropathy developed in 28% of patients and Grade 2 in 5%. The rates of Grade 1 and 2 joint stiffness were each 19%. Grade 1 edema was observed in 19% of patients and Grade 2 in 13%. The 2-year local control, distant control, and overall survival were 95%, 65%, and 81%, respectively. Conclusion: Intensity modulated RT appears to provide excellent local control in a difficult group of high-risk patients. The morbidity profile is also favorable, but longer follow-up is needed to confirm the results from this study.

  12. Forecasting hotspots using predictive visual analytics approach

    SciTech Connect

    Maciejewski, Ross; Hafen, Ryan; Rudolph, Stephen; Cleveland, William; Ebert, David

    2014-12-30

    A method for forecasting hotspots is provided. The method may include the steps of receiving input data at an input of the computational device, generating a temporal prediction based on the input data, generating a geospatial prediction based on the input data, and generating output data based on the time series and geospatial predictions. The output data may be configured to display at least one user interface at an output of the computational device.

  13. Means and Trends in Solar Radiation: Results From Two Global Data Sets and Effects on Estimated Net Primary Production

    NASA Astrophysics Data System (ADS)

    Hicke, J. A.

    2005-12-01

    Downwelling surface solar radiation is an important factor driving plant productivity, and clouds and aerosols are major factors responsible for interannual variability in downwelling radiation. Global ecosystem models require spatially extensive data sets that vary interannually to capture effects that potentially drive changes in ecosystem function. Representative global solar radiation data sets include National Centers for Environmental Prediction (NCEP) reanalyses and Goddard Institute for Space Studies (GISS) calculations that included satellite observations of cloud properties. The CASA light-use efficiency model, which utilizes solar radiation and satellite-derived vegetation information, was run with the two solar radiation data sets to explore how differences affect estimated net primary production (NPP). Mean global NCEP solar radiation exceeded that from GISS by 16%, likely as a result of lower cloudiness within the NCEP reanalyses compared to satellite observations. Neither data set resulted in a significant trend in growing season radiation over the study period (1984-2000). Locally, relative differences were up to 40% in the mean and 10% in the trend of solar radiation and NPP, and varied in sign across the globe.

  14. Role of radiation and non-radiation factors on the development of coronary heart disease in the Chornobyl clean-up workers: epidemiological study results.

    PubMed

    Krasnikova, L I; Buzunov, V O

    2014-09-01

    Objective. The objective of this study was to establish the risks for coronary heart disease in the Chornobyl clean-up workers with regard to a whole-body external radiation dose and non-radiation (biological, social-and-hygienic and behavioral) factors. Materials and methods. Risk-analysis was based on the cohort of the Chornobyl male clean-up workers 1986-1987 (8,625 men, including 3,623 with available whole-body external doses). Data of clinical-and-epidemiological registry, National Research Centre for Radiation Medicine were used for 1992-2013 monitoring period. We used the internal control group with radiation doses less than 0.05 Gy. Results. Statistically significant radiation risks in the Chornobyl clean-up workers were established for the coronary heart disease at doses 0.15-0.249 Gy, 0.25-0.99 Gy, 1 Gy and more (dose group 0.15-0.249 Gy RRY=1.9 (1.2; 3.1), ERR=4.6 (1.5; 14.9) Gy-1, EAR=64.2 cases per 1000 person-years, Gy); among exposed people aged 40 years and older - at doses 0.5-0.99 Gy (RRY=1.4 (1.05; 1.81), ERR=0.5 (0.03; 1.1) Gy-1, EAR=30.5 cases per 1000 person-years, Gy). Statistically significant risks for the disease under consideration were also identified with regard to non-radiation factors (smoking, improper physical training, adverse working conditions, diseases etc; age and psychoemotional overstrain were of a particular impact). Non-radiation factors are at most responsible for development of coronary heart disease. For this reason the control of potential confounding factors is required to assess the effect of the radiation factor both at a stage of comparison groups selection and analysis using the Mantel-Haenszel method.

  15. The history, hotspots, and trends of electrocardiogram

    PubMed Central

    Yang, Xiang-Lin; Liu, Guo-Zhen; Tong, Yun-Hai; Yan, Hong; Xu, Zhi; Chen, Qi; Liu, Xiang; Zhang, Hong-Hao; Wang, Hong-Bo; Tan, Shao-Hua

    2015-01-01

    The electrocardiogram (ECG) has broad applications in clinical diagnosis and prognosis of cardiovascular disease. Many researchers have contributed to its progressive development. To commemorate those pioneers, and to better study and promote the use of ECG, we reviewed and present here a systematic introduction about the history, hotspots, and trends of ECG. In the historical part, information including the invention, improvement, and extensive applications of ECG, such as in long QT syndrome (LQTS), angina, and myocardial infarction (MI), are chronologically presented. New technologies and applications from the 1990s are also introduced. In the second part, we use the bibliometric analysis method to analyze the hotspots in the field of ECG-related research. By using total citations and year-specific total citations as our main criteria, four key hotspots in ECG-related research were identified from 11 articles, including atrial fibrillation, LQTS, angina and MI, and heart rate variability. Recent studies in those four areas are also reported. In the final part, we discuss the future trends concerning ECG-related research. The authors believe that improvement of the ECG instrumentation, big data mining for ECG, and the accuracy of diagnosis and application will be areas of continuous concern. PMID:26345622

  16. The history, hotspots, and trends of electrocardiogram.

    PubMed

    Yang, Xiang-Lin; Liu, Guo-Zhen; Tong, Yun-Hai; Yan, Hong; Xu, Zhi; Chen, Qi; Liu, Xiang; Zhang, Hong-Hao; Wang, Hong-Bo; Tan, Shao-Hua

    2015-07-01

    The electrocardiogram (ECG) has broad applications in clinical diagnosis and prognosis of cardiovascular disease. Many researchers have contributed to its progressive development. To commemorate those pioneers, and to better study and promote the use of ECG, we reviewed and present here a systematic introduction about the history, hotspots, and trends of ECG. In the historical part, information including the invention, improvement, and extensive applications of ECG, such as in long QT syndrome (LQTS), angina, and myocardial infarction (MI), are chronologically presented. New technologies and applications from the 1990s are also introduced. In the second part, we use the bibliometric analysis method to analyze the hotspots in the field of ECG-related research. By using total citations and year-specific total citations as our main criteria, four key hotspots in ECG-related research were identified from 11 articles, including atrial fibrillation, LQTS, angina and MI, and heart rate variability. Recent studies in those four areas are also reported. In the final part, we discuss the future trends concerning ECG-related research. The authors believe that improvement of the ECG instrumentation, big data mining for ECG, and the accuracy of diagnosis and application will be areas of continuous concern.

  17. Classification Model for Forest Fire Hotspot Occurrences Prediction Using ANFIS Algorithm

    NASA Astrophysics Data System (ADS)

    Wijayanto, A. K.; Sani, O.; Kartika, N. D.; Herdiyeni, Y.

    2017-01-01

    This study proposed the application of data mining technique namely Adaptive Neuro-Fuzzy inference system (ANFIS) on forest fires hotspot data to develop classification models for hotspots occurrence in Central Kalimantan. Hotspot is a point that is indicated as the location of fires. In this study, hotspot distribution is categorized as true alarm and false alarm. ANFIS is a soft computing method in which a given inputoutput data set is expressed in a fuzzy inference system (FIS). The FIS implements a nonlinear mapping from its input space to the output space. The method of this study classified hotspots as target objects by correlating spatial attributes data using three folds in ANFIS algorithm to obtain the best model. The best result obtained from the 3rd fold provided low error for training (error = 0.0093676) and also low error testing result (error = 0.0093676). Attribute of distance to road is the most determining factor that influences the probability of true and false alarm where the level of human activities in this attribute is higher. This classification model can be used to develop early warning system of forest fire.

  18. Environmental niche conservatism explains the accumulation of species richness in Mediterranean-hotspot plant genera.

    PubMed

    Skeels, Alexander; Cardillo, Marcel

    2017-03-01

    The causes of exceptionally high plant diversity in Mediterranean-climate biodiversity hotspots are not fully understood. We asked whether a mechanism similar to the tropical niche conservatism hypothesis could explain the diversity of four large genera (Protea, Moraea, Banksia, and Hakea) with distributions within and adjacent to the Greater Cape Floristic Region (South Africa) or the Southwest Floristic Region (Australia). Using phylogenetic and spatial data we estimated the environmental niche of each species, and reconstructed the mode and dynamics of niche evolution, and the geographic history, of each genus. For three genera, there were strong positive relationships between the diversity of clades within a region and their inferred length of occupation of that region. Within genera, there was evidence for strong evolutionary constraint on niche axes associated with climatic seasonality and aridity, with different niche optima for hotspot and nonhotspot clades. Evolutionary transitions away from hotspots were associated with increases in niche breadth and elevated rates of niche evolution. Our results point to a process of "hotspot niche conservatism" whereby the accumulation of plant diversity in Mediterranean-type ecosystems results from longer time for speciation, with dispersal away from hotspots limited by narrow and phylogenetically conserved environmental niches.

  19. Alterations of CNS structure & function by charged particle radiation & resultant oxidative stress

    NASA Astrophysics Data System (ADS)

    Nelson, Gregory; Chang, Polly; Favre, Cecile; Fike, John; Komarova, Natalia; Limoli, Charles; Mao, Xiao-Wen; Obenaus, Andre; Raber, Jacob; Spigelman, Igor; Soltesz, Ivan; Song, Sheng-Kwei; Stampanoni, Marco; Vlkolinsky, Roman; Wodarz, Dominik

    were complex and suggested continuous remodeling of the brain for up to 6 months. Thus we demonstrated a suite of CNS structural and functional changes after proton and iron ion exposure in the low dose regime. Based on these findings we will now test whether oxidative stress mediates the reactions of CNS to radiation exposure and what role radiation quality and dose rate play in the responses. We will use cultured neural precursor cells (mouse human) to detect changes in oxidative status and differentiation as functions of charged particle charge and velocity. These results will inform the selection of particles for many in vivo measurements that will compare wild type mice to a transgenic strain that over-expresses a human catalase gene (which inactivates hydrogen peroxide) in the mitochondrial compartment. This will explicitly test the role of reactive oxygen species in mediating the mechanisms underlying the CNS endpoints that we will measure. We will extend the electrophysiological measurements on individual nerves in hippocampal slices to characterize both inhibitory and excitatory synapses. Further, multi-electrode arrays will be used to follow correlated electrical activity in different hippocampal regions in order to understand network-level function as well as synaptic efficacy and plasticity. Controlled oxidative stress on irradiated samples will explore whether response mechanisms are shared. To link alterations in neurogenesis to performance we will explore behavioral changes mediated by the hippocampus simultaneously with measures of expression of the Arc gene in newly-born neurons. This will test whether decrements in performance correlate with loss of new cells and whether behavior properly stimulates functional integration of the new cells; the behavioral paradigm will be contextual fear conditioning. We will develop mathematical frameworks for CNS responses to radiation in order to inform risk estimates. Finally, we will couple a high

  20. Oxidative Lung Damage Resulting from Repeated Exposure to Radiation and Hyperoxia Associated with Space Exploration

    PubMed Central

    Pietrofesa, Ralph A; Turowski, Jason B; Arguiri, Evguenia; Milovanova, Tatyana N; Solomides, Charalambos C; Thom, Stephen R; Christofidou-Solomidou, Melpo

    2013-01-01

    Background Spaceflight missions may require crewmembers to conduct Extravehicular Activities (EVA) for repair, maintenance or scientific purposes. Pre-breathe protocols in preparation for an EVA entail 100% hyperoxia exposure that may last for a few hours (5-8 hours), and may be repeated 2-3 times weekly. Each EVA is associated with additional challenges such as low levels of total body cosmic/galactic radiation exposure that may present a threat to crewmember health and therefore, pose a threat to the success of the mission. We have developed a murine model of combined, hyperoxia and radiation exposure (double-hit) in the context of evaluating countermeasures to oxidative lung damage associated with space flight. In the current study, our objective was to characterize the early and chronic effects of repeated single and double-hit challenge on lung tissue using a novel murine model of repeated exposure to low-level total body radiation and hyperoxia. This is the first study of its kind evaluating lung damage relevant to space exploration in a rodent model. Methods Mouse cohorts (n=5-15/group) were exposed to repeated: a) normoxia; b) >95% O2 (O2); c) 0.25Gy single fraction gamma radiation (IR); or d) a combination of O2 and IR (O2+IR) given 3 times per week for 4 weeks. Lungs were evaluated for oxidative damage, active TGFβ1 levels, cell apoptosis, inflammation, injury, and fibrosis at 1, 2, 4, 8, 12, 16, and 20 weeks post-initiation of exposure. Results Mouse cohorts exposed to all challenge conditions displayed decreased bodyweight compared to untreated controls at 4 and 8 weeks post-challenge initiation. Chronic oxidative lung damage to lipids (malondialdehyde levels), DNA (TUNEL, cleaved Caspase 3, cleaved PARP positivity) leading to apoptotic cell death and to proteins (nitrotyrosine levels) was elevated all treatment groups. Importantly, significant systemic oxidative stress was also noted at the late phase in mouse plasma, BAL fluid, and urine. Importantly

  1. Radiation Test Results for a MEMS Microshutter Operating at 60 K

    NASA Technical Reports Server (NTRS)

    Rapchun, David A.; Buchner, Stephen; Moseley, Harvey; Meyer, Stephen E.; Ray, Knute; Tuttle, Jim; Quinn, Ed; Buchanan, Ernie; Bloom, Dave; Hait, Tom; Pearce, Mike; Beamer, A.

    2007-01-01

    MEMS. Knowledge of the above principle has raised the concern at NASA that the MSA might also exhibit degraded performance because, i) each shutter flap is a multilayer structure consisting of metallic and insulating layers and ii) the movement of the shutter flaps is partially controlled by the application of an electric field between the shutter flap and the substrate (vertical support grid). The whole mission would be compromised if radiation exposure were to prevent the shutters from opening and closing properly. energetic ionizing particles. Because it is located A unique feature of the MSA is that, as outside the spacecraft and has very little shielding, previously mentioned, it will have to operate at temperatures near 30 K. To date, there are no published reports on how very low temperatures (- 30K) affect the response of MEMS devices to total ionizing dose. Experiments on SiO2 structures at low temperatures (80 K) indicate that the electrons generated by the ionizing radiation are mobile and will move rapidly under the application of an external electric field. Holes, on the other hand, that would normally move in the opposite direction through the SiO2 via a "thermal hopping" process, are effectively immobile at low electric fields as they are trapped close to their generation sites. However, for sufficiently large electric fields (greater than 3 MV/cm) holes are able to move through the SiO2. The larger the field, the more rapidly the holes move. The separation of the electrons and holes leads to a reduced electric field within the insulating layer. To overcome this reduction in electric field, a greater external voltage will have to be applied that alters the normal operation of the device. This report presents the results of radiation testing of the MSA at 60 K. The temperature was higher than the targeted temperature because of a faulty electrical interconnect on the test board. Specifically, our goal was to determine whether the MSA would function propey

  2. The implications of the COBE diffuse microwave radiation results for cosmic strings

    NASA Technical Reports Server (NTRS)

    Bennett, David P.; Stebbins, Albert; Bouchet, Francois R.

    1992-01-01

    We compare the anisotropies in the cosmic microwave background radiation measured by the COBE experiment to those predicted by cosmic string theories. We use an analytic model for the Delta T/T power spectrum that is based on our previous numerical simulations of strings, under the assumption that cosmic strings are the sole source of the measured anisotropy. This implies a value for the string mass per unit length of 1.5 +/- 0.5 x 10 exp -6 C-squared/G. This is within the range of values required for cosmic strings to successfully seed the formation of large-scale structures in the universe. These results clearly encourage further studies of Delta T/T and large-scale structure in the cosmic string model.

  3. Code System for Calculating Radiation Exposure Resulting from Accidental Radioactive Releases to the Hydrosphere.

    SciTech Connect

    1982-11-18

    Version 00 LPGS was developed to calculate the radiological impacts resulting from radioactive releases to the hydrosphere. The name LPGS was derived from the Liquid Pathway Generic Study for which the original code was used primarily as an analytic tool in the assessment process. The hydrosphere is represented by the following types of water bodies: estuary, small river, well, lake, and one-dimensional (1-D) river. LPGS is designed to calculate radiation dose (individual and population) to body organs as a function of time for the various exposure pathways. The radiological consequences to the aquatic biota are estimated. Several simplified radionuclide transport models are employed with built-in formulations to describe the release rate of the radionuclides. A tabulated user-supplied release model can be input, if desired. Printer plots of dose versus time for the various exposure pathways are provided.

  4. Estimation of the committed radiation dose resulting from gamma radionuclides ingested with food.

    PubMed

    Godyń, Piotr; Dołhańczuk-Śródka, Agnieszka; Ziembik, Zbigniew; Moliszewska, Ewa

    The objective of the study was to estimate the value of the radiation dose absorbed in consequence of consumption of popular food products for individual age groups. Potatoes, corn and sugar beet were selected for the study. Edible parts of these plants were collected in experimental fields of the KWS Lochów Polska Sp. z o.o. seeding company in Kondratowice (Poland). On the basis of the obtained study results, it can be stated that in consequence of consumption of the selected food products, people may receive increased doses from both natural and artificial radioactive isotopes. The doses calculated for several age groups do not show any health hazards in consequence of consumption of the tested food. One of the determined radionuclides was (137)Cs; however, its presence in the absorbed dose is lower than the doses from natural radioactive isotopes, in particular (40)K.

  5. Examination results of the Three Mile Island radiation detector HP-R-212

    SciTech Connect

    Mueller, G.M.

    1983-12-01

    Area radiation detector HP-R-212 was removed from the Three Mile Island containment building on November 13, 1981. The detector apparently started to fail during November 1979 and by the first part of December 1979 the detector readings had degraded from 1 R/hr to 20 mR/hr. This report discusses the cause of failure, detector radiation measurement characteristics, and our estimates of the total gamma radiation dose received by the detector electronics.

  6. Examination results of the Three Mile Island radiation detector HP-R-212

    SciTech Connect

    Mueller, G M

    1984-01-01

    Area radiation detector HP-R-212 was removed from the Three Mile Island containment building on November 13, 1981. The detector apparently started to fail during November 1979 and by the first part of December 1979 the detector readings had degraded from 1 R/h to 20 mR/h. This report discusses the cause of ailure, detector radiation measurement characteristics, and our estimates of the total gamma radiation dose received by the detector electronics.

  7. EFFECTS OF LASER RADIATION ON MATTER. LASER PLASMA: Spatial-temporal distribution of a mechanical load resulting from interaction of laser radiation with a barrier (analytic model)

    NASA Astrophysics Data System (ADS)

    Fedyushin, B. T.

    1992-01-01

    The concepts developed earlier are used to propose a simple analytic model describing the spatial-temporal distribution of a mechanical load (pressure, impulse) resulting from interaction of laser radiation with a planar barrier surrounded by air. The correctness of the model is supported by a comparison with experimental results.

  8. Amsterdam-St. Paul Hotspot: Composition, Motion and History

    NASA Astrophysics Data System (ADS)

    Janin, Myriam; Hemond, Christophe; Maia, Marcia; Guillou, Herve; Nonnotte, Philippe; Ponzevera, Emmanuel

    2010-05-01

    The Amsterdam-St Paul (ASP) plateau results of the excess of melting induced by the interaction between the ASP hotspot and the South-East Indian Ridge. The ASP plume was originally located beneath the Australian Plate and its interaction with the SEIR began about 10 Ma ago. This location provides an unique opportunity to study the hotspot prior to its interaction with the SEIR and its chemical and physical evolution. An exhaustive study of the hotspot characteristics prior to its interaction lead to know its geochemical compositions. The geochemistry of its interaction with the SEIR (i. e. ASP plateau) provides indirect information on the regional Indian Ocean upper mantle. ASP plume has a moderately enriched composition with resulting seamount melts having 2.5 < (La/Sm)C1norm < 2.8. In addition isotope ratios are not as extreme as estimated in previous works [Doucet et al. 2004; Nicolaysen et al., 2007] with 86Sr/87Sr ≈ 0.7040, 143Nd/144Nd ≈ 0.5128, 206Pb/204Pb ≈ 19.0 and 208Pb/204Pb ≈ 39.2. The ASP plateau isotopic composition reveals that the Indian Ocean upper mantle is extremely heterogeneous. It was proposed that the ridge segments across the plateau have interacted 40 My ago with Kerguelen plume [Frey et al. 2000]. We therefore assume that some plume material has been left behind in the Indian Ocean upper mantle during the movement of the Australian plate above it. Consequently, the upper mantle in the area might be a good example of 'marble cake' [Allegre&Turcotte, 1986]. When the SEIR approaches the ASP hotspot, plume derived material mixes with the surrounded mantle leading to the complexity seen in ASP plateau materials. K-Ar datings reveal that the absolute motion of the Australian plate calculated with respect to the fixity of ASP plume is of about 77 km/My. With a spreading rate of about 6-7 cm/yr the accretion at the SEIR axis cannot account for this velocity. In consequence, an absolute motion of the ASP plume of about 10-20km

  9. Assessment of outdoor radiofrequency electromagnetic field exposure through hotspot localization using kriging-based sequential sampling

    SciTech Connect

    Aerts, Sam Deschrijver, Dirk; Verloock, Leen; Dhaene, Tom; Martens, Luc; Joseph, Wout

    2013-10-15

    In this study, a novel methodology is proposed to create heat maps that accurately pinpoint the outdoor locations with elevated exposure to radiofrequency electromagnetic fields (RF-EMF) in an extensive urban region (or, hotspots), and that would allow local authorities and epidemiologists to efficiently assess the locations and spectral composition of these hotspots, while at the same time developing a global picture of the exposure in the area. Moreover, no prior knowledge about the presence of radiofrequency radiation sources (e.g., base station parameters) is required. After building a surrogate model from the available data using kriging, the proposed method makes use of an iterative sampling strategy that selects new measurement locations at spots which are deemed to contain the most valuable information—inside hotspots or in search of them—based on the prediction uncertainty of the model. The method was tested and validated in an urban subarea of Ghent, Belgium with a size of approximately 1 km{sup 2}. In total, 600 input and 50 validation measurements were performed using a broadband probe. Five hotspots were discovered and assessed, with maximum total electric-field strengths ranging from 1.3 to 3.1 V/m, satisfying the reference levels issued by the International Commission on Non-Ionizing Radiation Protection for exposure of the general public to RF-EMF. Spectrum analyzer measurements in these hotspots revealed five radiofrequency signals with a relevant contribution to the exposure. The radiofrequency radiation emitted by 900 MHz Global System for Mobile Communications (GSM) base stations was always dominant, with contributions ranging from 45% to 100%. Finally, validation of the subsequent surrogate models shows high prediction accuracy, with the final model featuring an average relative error of less than 2 dB (factor 1.26 in electric-field strength), a correlation coefficient of 0.7, and a specificity of 0.96. -- Highlights: • We present an

  10. The impact of hotspot-targeted interventions on malaria transmission: study protocol for a cluster-randomized controlled trial

    PubMed Central

    2013-01-01

    Background Malaria transmission is highly heterogeneous in most settings, resulting in the formation of recognizable malaria hotspots. Targeting these hotspots might represent a highly efficacious way of controlling or eliminating malaria if the hotspots fuel malaria transmission to the wider community. Methods/design Hotspots of malaria will be determined based on spatial patterns in age-adjusted prevalence and density of antibodies against malaria antigens apical membrane antigen-1 and merozoite surface protein-1. The community effect of interventions targeted at these hotspots will be determined. The intervention will comprise larviciding, focal screening and treatment of the human population, distribution of long-lasting insecticide-treated nets and indoor residual spraying. The impact of the intervention will be determined inside and up to 500 m outside the targeted hotspots by PCR-based parasite prevalence in cross-sectional surveys, malaria morbidity by passive case detection in selected facilities and entomological monitoring of larval and adult Anopheles populations. Discussion This study aims to provide direct evidence for a community effect of hotspot-targeted interventions. The trial is powered to detect large effects on malaria transmission in the context of ongoing malaria interventions. Follow-up studies will be needed to determine the effect of individual components of the interventions and the cost-effectiveness of a hotspot-targeted approach, where savings made by reducing the number of compounds that need to receive interventions should outweigh the costs of hotspot-detection. Trial registration NCT01575613. The protocol was registered online on 20 March 2012; the first community was randomized on 26 March 2012. PMID:23374910

  11. The Cobb-Eickelberg seamount chain: Hotspot volcanism with mid-ocean ridge basalt affinity

    SciTech Connect

    Desonie, D.L.; Duncan, R.A. )

    1990-08-10

    Cobb hotspot, currently located beneath Axial seamount on the Juan de Fuca ridge, has the temporal but not the isotopic characteristics usually attributed to a mantle plume. The earlier volcanic products of the hotspot, form eight volcanoes in the Cobb-Eickelberg seamount (CES) chain, show a westward age progression away from the hotspot and a westward increase in the age difference between the seamounts and the crust on which they formed. These results are consistent with movement of the Pacific plate over a fixed Cobb hotspot and eventual encroachment by the westwardly migrating Juan de Fuca ridge. CES lavas are slightly enriched in alkalies and incompatible elements relative to those of the Juan de Fuca ridge but they have Sr, Nd, and Pb isotopic compositions virtually identical to those found along the ridge. Therefore, Cobb hotspot is a stationary, upper mantle melting anomaly whose volcanic products show strong mid-ocean ridge basalt (MORB) affinity. These observations can be explained by low degrees of partial melting of entrained heterogeneous upper mantle MORB source material within a thermally driven lower mantle diapir or by an intrinsic MORB-like composition of the deeper mantle source region from which northeast Pacific plumes rise.

  12. Persistence of trophic hotspots and relation to human impacts within an upwelling marine ecosystem.

    PubMed

    Santora, Jarrod A; Sydeman, William J; Schroeder, Isaac D; Field, John C; Miller, Rebecca R; Wells, Brian K

    2017-03-01

    Human impacts (e.g., fishing, pollution, and shipping) on pelagic ecosystems are increasing, causing concerns about stresses on marine food webs. Maintaining predator-prey relationships through protection of pelagic hotspots is crucial for conservation and management of living marine resources. Biotic components of pelagic, plankton-based, ecosystems exhibit high variability in abundance in time and space (i.e., extreme patchiness), requiring investigation of persistence of abundance across trophic levels to resolve trophic hotspots. Using a 26-yr record of indicators for primary production, secondary (zooplankton and larval fish), and tertiary (seabirds) consumers, we show distributions of trophic hotspots in the southern California Current Ecosystem result from interactions between a strong upwelling center and a productive retention zone with enhanced nutrients, which concentrate prey and predators across multiple trophic levels. Trophic hotspots also overlap with human impacts, including fisheries extraction of coastal pelagic and groundfish species, as well as intense commercial shipping traffic. Spatial overlap of trophic hotspots with fisheries and shipping increases vulnerability of the ecosystem to localized depletion of forage fish, ship strikes on marine mammals, and pollution. This study represents a critical step toward resolving pelagic areas of high conservation interest for planktonic ecosystems and may serve as a model for other ocean regions where ecosystem-based management and marine spatial planning of pelagic ecosystems is warranted.

  13. Micron-scale Reactive Atomistic Simulation of Void Collapse and Hotspot Growth in PETN

    NASA Astrophysics Data System (ADS)

    Thompson, Aidan; Shan, Tzu-Ray

    2014-03-01

    Material defects and heterogeneities such as dislocations, grain boundaries, and micro-porosity play key roles in the shock-induced initiation of detonation in energetic materials. Non-equilibrium molecular dynamics simulations (NEMD) with the ReaxFF force field (ReaxFF) in LAMMPS were performed to explore the effect of nanoscale voids on hotspot growth and initiation in pentaerythritol tetranitrate (PETN) crystals under weak shock conditions. Previously, we have performed reactive NEMD simulations of weak shocks in a (20 nm) 3 PETN crystal containing a spherical void. We observed hotspot formation and an exothermic reaction zone. To observe growth of the hotspot, we have now greatly extended the time and lengthscale of the simulation. We created a cylindrical pore in a 0 . 3 × 0 . 2 × 0 . 001 μm3 crystal. Once the shockwave reached the free surface we continued the simulation using the shock-front absorbing boundary condition. Results show steadily increasing axial and lateral spatial extent of the hotspot and a complex coupling of exothermic chemistry to hotspot growth. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy NNSA under contract DE-AC04-94AL85000.

  14. Beam Output Audit results within the EORTC Radiation Oncology Group network.

    PubMed

    Hurkmans, Coen W; Christiaens, Melissa; Collette, Sandra; Weber, Damien Charles

    2016-12-15

    Beam Output Auditing (BOA) is one key process of the EORTC radiation therapy quality assurance program. Here the results obtained between 2005 and 2014 are presented and compared to previous results.For all BOA reports the following parameters were scored: centre, country, date of audit, beam energies and treatment machines audited, auditing organisation, percentage of agreement between stated and measured dose.Four-hundred and sixty-one BOA reports were analyzed containing the results of 1790 photon and 1366 electron beams, delivered by 755 different treatment machines. The majority of beams (91.1%) were within the optimal limit of ≤ 3%. Only 13 beams (0.4%; n = 9 electrons; n = 4 photons), were out of the range of acceptance of ≤ 5%. Previous reviews reported a much higher percentage of 2.5% or more of the BOAs with >5% deviation.The majority of EORTC centres present beam output variations within the 3% tolerance cutoff value and only 0.4% of audited beams presented with variations of more than 5%. This is an important improvement compared to previous BOA results.

  15. Radiation Hardening by Software Techniques on FPGAs: Flight Experiment Evaluation and Results

    NASA Technical Reports Server (NTRS)

    Schmidt, Andrew G.; Flatley, Thomas

    2017-01-01

    We present our work on implementing Radiation Hardening by Software (RHBSW) techniques on the Xilinx Virtex5 FPGAs PowerPC 440 processors on the SpaceCube 2.0 platform. The techniques have been matured and tested through simulation modeling, fault emulation, laser fault injection and now in a flight experiment, as part of the Space Test Program- Houston 4-ISS SpaceCube Experiment 2.0 (STP-H4-ISE 2.0). This work leverages concepts such as heartbeat monitoring, control flow assertions, and checkpointing, commonly used in the High Performance Computing industry, and adapts them for use in remote sensing embedded systems. These techniques are extremely low overhead (typically <1.3%), enabling a 3.3x gain in processing performance as compared to the equivalent traditionally radiation hardened processor. The recently concluded STP-H4 flight experiment was an opportunity to upgrade the RHBSW techniques for the Virtex5 FPGA and demonstrate them on-board the ISS to achieve TRL 7. This work details the implementation of the RHBSW techniques, that were previously developed for the Virtex4-based SpaceCube 1.0 platform, on the Virtex5-based SpaceCube 2.0 flight platform. The evaluation spans the development and integration with flight software, remotely uploading the new experiment to the ISS SpaceCube 2.0 platform, and conducting the experiment continuously for 16 days before the platform was decommissioned. The experiment was conducted on two PowerPCs embedded within the Virtex5 FPGA devices and the experiment collected 19,400 checkpoints, processed 253,482 status messages, and incurred 0 faults. These results are highly encouraging and future work is looking into longer duration testing as part of the STP-H5 flight experiment.

  16. Ipilimumab with Stereotactic Ablative Radiation Therapy: Phase I Results and Immunologic Correlates from Peripheral T Cells.

    PubMed

    Tang, Chad; Welsh, James W; de Groot, Patricia; Massarelli, Erminia; Chang, Joe Y; Hess, Kenneth R; Basu, Sreyashi; Curran, Michael A; Cabanillas, Maria E; Subbiah, Vivek; Fu, Siqing; Tsimberidou, Apostolia M; Karp, Daniel; Gomez, Daniel R; Diab, Adi; Komaki, Ritsuko; Heymach, John V; Sharma, Padmanee; Naing, Aung; Hong, David S

    2017-03-15

    Purpose: Little prospective data are available on clinical outcomes and immune correlates from combination radiation and immunotherapy. We conducted a phase I trial (NCT02239900) testing stereotactic ablative radiotherapy (SABR) with ipilimumab.Experimental Design: SABR was given either concurrently (1 day after the first dose) or sequentially (1 week after the second dose) with ipilimumab (3 mg/kg every 3 weeks for 4 doses) to five treatment groups: concurrent 50 Gy (in 4 fractions) to liver; sequential 50 Gy (in 4 fractions) to liver; concurrent 50 Gy (in 4 fractions) to lung; sequential 50 Gy (in 4 fractions) to lung; and sequential 60 Gy (in 10 fractions) to lung or liver. MTD was determined with a 3 + 3 dose de-escalation design. Immune marker expression was assessed by flow cytometry.Results: Among 35 patients who initiated ipilimumab, 2 experienced dose-limiting toxicity and 12 (34%) grade 3 toxicity. Response outside the radiation field was assessable in 31 patients. Three patients (10%) exhibited partial response and 7 (23%) experienced clinical benefit (defined as partial response or stable disease lasting ≥6 months). Clinical benefit was associated with increases in peripheral CD8(+) T cells, CD8(+)/CD4(+) T-cell ratio, and proportion of CD8(+) T cells expressing 4-1BB and PD1. Liver (vs. lung) irradiation produced greater T-cell activation, reflected as increases in the proportions of peripheral T cells expressing ICOS, GITR, and 4-1BB.Conclusions: Combining SABR and ipilimumab was safe with signs of efficacy, peripheral T-cell markers may predict clinical benefit, and systemic immune activation was greater after liver irradiation. Clin Cancer Res; 23(6); 1388-96. ©2016 AACR.

  17. A Survey of DICER1 Hotspot Mutations in Ovarian and Testicular Sex Cord-Stromal Tumors

    PubMed Central

    Conlon, Niamh; Schultheis, Anne M; Piscuoglio, Salvatore; Silva, Annacarolina; Guerra, Esther; Tornos, Carmen; Reuter, Victor E; Soslow, Robert A; Young, Robert H; Oliva, Esther; Weigelt, Britta

    2015-01-01

    Sertoli-Leydig cell tumors are characterized by the presence of somatic DICER1 hotspot mutations. In this study, we sought to define the association between DICER1 hotspot mutations and different morphologic subtypes of ovarian Sertoli-Leydig cell tumors. Furthermore, we aimed to assess whether DICER1 hotspot mutations occur in other ovarian sex cord-stromal tumors, testicular sex cord-stromal tumors, or other female genital tract tumors with rhabdomyosarcomatous differentiation. We subjected a series of ovarian Sertoli-Leydig cell tumors (n=32), Sertoli cell tumors (n=5) and gynandroblastomas (n=5), testicular sex cord-stromal tumors (n=15) and a diverse group of female genital tract tumors with rhabdomyosarcomatous morphology (n=10) to DICER1 hotspot mutation analysis using Sanger sequencing. We also tested 2 gynandroblastomas for the presence of FOXL2 hotspot mutations (p.C134W; c.402C>G). Twenty of 32 (63%) Sertoli-Leydig cell tumors harbored a DICER1 hotspot mutation, of which 80% had the p.E1705K mutation. No association was found between DICER1 mutation status and the presence of heterologous or retiform differentiation in Sertoli-Leydig cell tumors. DICER1 mutations were found at similar frequencies in gynandroblastoma (2/5; 40%) and ovarian Sertoli cell tumors (5/8; 63%; p>0.1), and all mutated tumors harbored a p.E1705K mutation. DICER1 hotspot mutations were also identified in a single cervical rhabdomyosarcoma and in the rhabdomyosarcomatous component of a uterine carcinosarcoma. No DICER1 mutations were detected in testicular sex cord-stromal tumors. Two DICER1 wild-type gynandroblastomas harbored a p.C134W FOXL2 hotspot mutation in both tumor components. In this study we confirmed that DICER1 hotspot mutations occur in over half of ovarian Sertoli-Leydig cell tumors, and are unrelated to tumor differentiation. We also widened the spectrum of ovarian sex cord-stromal tumors with sertoliform differentiation, in which DICER1 mutations are known to occur

  18. A survey of DICER1 hotspot mutations in ovarian and testicular sex cord-stromal tumors.

    PubMed

    Conlon, Niamh; Schultheis, Anne M; Piscuoglio, Salvatore; Silva, Annacarolina; Guerra, Esther; Tornos, Carmen; Reuter, Victor E; Soslow, Robert A; Young, Robert H; Oliva, Esther; Weigelt, Britta

    2015-12-01

    Sertoli-Leydig cell tumors are characterized by the presence of somatic DICER1 hotspot mutations. In this study, we sought to define the association between DICER1 hotspot mutations and different morphologic subtypes of ovarian Sertoli-Leydig cell tumors. Furthermore, we aimed to assess whether DICER1 hotspot mutations occur in other ovarian sex cord-stromal tumors, testicular sex cord-stromal tumors, or other female genital tract tumors with rhabdomyosarcomatous differentiation. We subjected a series of ovarian Sertoli-Leydig cell tumors (n=32), Sertoli cell tumors (n=5) and gynandroblastomas (n=5), testicular sex cord-stromal tumors (n=15) and a diverse group of female genital tract tumors with rhabdomyosarcomatous morphology (n=10) to DICER1 hotspot mutation analysis using Sanger sequencing. We also tested two gynandroblastomas for the presence of FOXL2 hotspot mutations (p.C134W; c.402C>G). Twenty of 32 (63%) Sertoli-Leydig cell tumors harbored a DICER1 hotspot mutation, of which 80% had the p.E1705K mutation. No association was found between DICER1 mutation status and the presence of heterologous or retiform differentiation in Sertoli-Leydig cell tumors. DICER1 mutations were found at similar frequencies in gynandroblastoma (2/5; 40%) and ovarian Sertoli cell tumors (5/8; 63%; P>0.1), and all mutated tumors harbored a p.E1705K mutation. DICER1 hotspot mutations were also identified in a single cervical rhabdomyosarcoma and in the rhabdomyosarcomatous component of a uterine carcinosarcoma. No DICER1 mutations were detected in testicular sex cord-stromal tumors. Two DICER1 wild-type gynandroblastomas harbored a p.C134W FOXL2 hotspot mutation in both tumor components. In this study we confirmed that DICER1 hotspot mutations occur in over half of ovarian Sertoli-Leydig cell tumors, and are unrelated to tumor differentiation. We also widened the spectrum of ovarian sex cord-stromal tumors with sertoliform differentiation, in which DICER1 mutations are known to

  19. Spatial temporal clustering for hotspot using kulldorff scan statistic method (KSS): A case in Riau Province

    NASA Astrophysics Data System (ADS)

    Hudjimartsu, S. A.; Djatna, T.; Ambarwari, A.; Apriliantono

    2017-01-01

    The forest fires in Indonesia occurs frequently in the dry season. Almost all the causes of forest fires are caused by the human activity itself. The impact of forest fires is the loss of biodiversity, pollution hazard and harm the economy of surrounding communities. To prevent fires required the method, one of them with spatial temporal clustering. Spatial temporal clustering formed grouping data so that the results of these groupings can be used as initial information on fire prevention. To analyze the fires, used hotspot data as early indicator of fire spot. Hotspot data consists of spatial and temporal dimensions can be processed using the Spatial Temporal Clustering with Kulldorff Scan Statistic (KSS). The result of this research is to the effectiveness of KSS method to cluster spatial hotspot in a case within Riau Province and produces two types of clusters, most cluster and secondary cluster. This cluster can be used as an early fire warning information.

  20. Detecting fluorescence hot-spots using mosaic maps generated from multimodal endoscope imaging

    NASA Astrophysics Data System (ADS)

    Yang, Chenying; Soper, Timothy D.; Seibel, Eric J.

    2013-03-01

    Fluorescence labeled biomarkers can be detected during endoscopy to guide early cancer biopsies, such as high-grade dysplasia in Barrett's Esophagus. To enhance intraoperative visualization of the fluorescence hot-spots, a mosaicking technique was developed to create full anatomical maps of the lower esophagus and associated fluorescent hot-spots. The resultant mosaic map contains overlaid reflectance and fluorescence images. It can be used to assist biopsy and document findings. The mosaicking algorithm uses reflectance images to calculate image registration between successive frames, and apply this registration to simultaneously acquired fluorescence images. During this mosaicking process, the fluorescence signal is enhanced through multi-frame averaging. Preliminary results showed that the technique promises to enhance the detectability of the hot-spots due to enhanced fluorescence signal.

  1. Phase II Radiation Therapy Oncology Group trial of conventional radiation therapy followed by treatment with recombinant interferon-{beta} for supratentorial glioblastoma: Results of RTOG 9710

    SciTech Connect

    Colman, Howard . E-mail: hcolman@mdanderson.org; Berkey, Brian A.; Maor, Moshe H.; Groves, Morris D.; Schultz, Christopher J.; Vermeulen, Sandra; Mehta, Minesh P.; Yung, W.K. Alfred

    2006-11-01

    Purpose: The aim of this study was to determine whether recombinant human interferon {beta}-1a (rhIFN-{beta}), when given after radiation therapy, improves survival in glioblastoma. Methods and Materials: After surgery, 109 patients with newly diagnosed supratentorial glioblastoma were enrolled and treated with radiation therapy (60 Gy). A total of 55 patients remained stable after radiation and were treated with rhIFN-{beta} (6 MU/day i.m., 3 times/week). Outcomes were compared with Radiation Therapy Oncology Group glioma historical database. Results: RhIFN-{beta} was well tolerated, with 1 Grade 4 toxicity and 8 other patients experiencing Grade 3 toxicity. Median survival time (MST) of the 55 rhIFN-{beta}-treated patients was 13.4 months. MST for the 34 rhIFN-{beta}-treated in RPA Classes III and IV was 16.9 vs. 12.4 months for historical controls (hazard ratio [HR] = 1.27, 95% confidence interval [CI] = 0.89-1.81). There was also a trend toward improved survival across all RPA Classes comparing the 55 rhIFN-{beta} treated patients and 1,658 historical controls (HR = 1.24, 95% CI = 0.94-1.63). The high rate of early failures (54/109) after radiation and before initiation of rhIFN-{beta} was likely caused by stricter interpretation of early radiographic changes in the current study. Matched-pair and intent-to-treat analyses performed to try to address this bias showed no difference in survival between study patients and controls. Conclusion: RhIFN-{beta} given after conventional radiation therapy was well tolerated, with a trend toward survival benefit in patients who remained stable after radiation therapy. These data suggest that rhIFN-{beta} warrants further evaluation in additional studies, possibly in combination with current temozolomide-based regimens.

  2. Hydrothermal Manganese Mineralization Near the Samoan Hotspot

    NASA Astrophysics Data System (ADS)

    Hein, J. R.; Staudigel, H.; Koppers, A.; Hart, S. R.; Dunham, R.

    2006-12-01

    The thickest beds of hydrothermal manganese oxides recovered to date from the global ocean were collected from a volcanic cone in the south Pacific. In April 2005, samples were dredged aboard the R.V. Kilo Moana from a volcanic cone on the lower flank of Tulaga seamount (about 2,700 m water depth; 14° 39.222' S; 170° 1.730' W), located 115 km SW of Vailulu'u, the volcanically and hydrothermally active center of the Samoan hotspot. Additional hydrothermal manganese samples were collected off Ofu Island (dredge Alia 107), 72 km to the WSW of Vailulu'u. Manganese-oxide beds up to 9 cm thick are composed of birnessite and 10 Å manganates. Some layers consist of Mn-oxide columnar structures 4 cm long and 1 cm wide, which have not been described previously. The mean Mn and Fe contents of 18 samples are 51 weight percent and 0.76 weight percent, respectively. Elevated concentrations of Li (mean 0.11 wt. percent) are indicators of a hydrothermal origin, and distinguishes these samples, along with the high Mn and low Fe contents, from hydrogenetic Fe-Mn crusts. Other enriched elements include Ba (mean 0.14 percent), Cu (249 ppm), Mo (451 ppm), Ni (400 ppm), Zn (394 ppm), V (214 ppm), and W (132 ppm). Chondrite-normalized REE patterns show large negative Ce anomalies and LREE enrichments, both characteristic of hydrothermal Mn deposits. Small negative Eu anomalies are not typical of hydrothermal deposits and can be explained either by the absence of leaching of plagioclase by the hydrothermal fluids or by the precipitation of Eu-rich minerals, such as barite and anhydrite, at depth. The high base-metal contents indicate that sulfides are not forming deeper in the hydrothermal system or that such deposits are being leached by the ascending fluids. Textures of the thickest Mn deposits indicate that the Mn oxides formed below the seabed from ascending fluids during multiple phases of waxing and waning hydrothermal pulses. The deposits were later exposed at the seafloor by

  3. The Rurutu Hotspot: Isotopic and Trace Element Evidence of HIMU Hotspot Volcanism in the Tuvalu Islands

    NASA Astrophysics Data System (ADS)

    Finlayson, V.; Konter, J. G.; Konrad, K.; Koppers, A. A. P.; Jackson, M. G.

    2014-12-01

    Current Pacific absolute plate motion (APM) models include 2 major, long-lived hotspot tracks: the ~85 Ma Hawaiian-Emperor and the ~76 Ma Louisville tracks. Prior to ~50 Ma, these two hotspot tracks show significant inter-hotspot drift, mainly due to large southern motion of the Hawaiian hotspot [1,2]. A third track would allow for a more robust evaluation of the relationship between APM models and inter-hotspot drift. We present trace element and Pb isotope evidence for a potential third long-lived Pacific hotspot trail—the Rurutu hotspot—anchored in the Cook-Austral Islands. Based on high 206Pb/204Pb ratios, 70-55 Ma volcanism in the Gilbert Ridge has been linked to the Rurutu hotspot [3]. The Gilbert Ridge may continue south into the Tuvalu Islands, where APM models predict that the Rurutu hotspot track captures the change in Pacific plate motion around 50 Ma at the intersection of Tuvalu and Samoa. Sampling of the deep submarine flanks of atolls and seamounts in Tuvalu and westernmost Samoa took place during the 2013 RR1310 (R/V Roger Revelle) expedition. We present new Pb isotope and HFSE trace element data on 28 samples that support a Rurutu origin for Tuvalu volcanism and confirm HIMU signatures previously observed in 5 Tuvalu samples (206Pb/204Pb >20.1, several >21.0; 87Sr/86Sr < 0.705). Statistical tests indicate that Tuvalu HFSE element ratios show similarities with Cook-Austral HIMU and differences with Samoa EMII volcanism. Low Hf/Nb ratios are often a predictor of HIMU samples (206Pb/204Pb > 20.8). Moderately HIMU compositions (206Pb/204Pb = 20.0) correspond to slightly higher Hf/Nb. In an effort to test if compositional agreement with the Cook-Australs is reflected in an age progression, 40Ar/39Ar ages will be presented by Konrad et al. (this volume). [1] Tarduno et al., (2003) DOI:10.1126/science.1086442 [2] Koppers et al., (2012) DOI: 10.1038/ngeo1638 [3] Konter et al., (2008) DOI: 10.1016/j.epsl.2008.08.023

  4. Subjective Reaction to Structurally Radiated Sound from Underground Railways: Field Results

    NASA Astrophysics Data System (ADS)

    Vadillo, E. G.; Herreros, J.; Walker, J. G.

    1996-05-01

    Structurally radiated noise from underground railways is becoming a major problem for railways administrations, due to the increase in the number of tunnels in urban areas, and to the increase in train speeds, wheelset tonnage and operation frequency. As a result, the number of complaints from residents living above railway tunnels is also increasing. Several control measures have been proposed in the past 15 years, both for the track design and for the vehicle design. Nevertheless, these measures are expensive, and not always effective. While several standards have been proposed for vibration limits in the type of problem, there are few standards to define acceptable levels for this type of structure-borne sound. This paper presents field results obtained during 1994 and 1995 in the vicinity of underground railways, where measurements of vibration and low-frequency noise were obtained during train pass-bys. These results, together with measurements of environment noise due to other sources, are considered together with the responses to a questionnaire completed by the people by the people affected. This paper complements laboratory work carried out at the ISVR [1].

  5. DNA barcoding of Rhododendron (Ericaceae), the largest Chinese plant genus in biodiversity hotspots of the Himalaya-Hengduan Mountains.

    PubMed

    Yan, Li-Jun; Liu, Jie; Möller, Michael; Zhang, Lin; Zhang, Xue-Mei; Li, De-Zhu; Gao, Lian-Ming

    2015-07-01

    The Himalaya-Hengduan Mountains encompass two global biodiversity hotspots with high levels of biodiversity and endemism. This area is one of the diversification centres of the genus Rhododendron, which is recognized as one of the most taxonomically challenging plant taxa due to recent adaptive radiations and rampant hybridization. In this study, four DNA barcodes were evaluated on 531 samples representing 173 species of seven sections of four subgenera in Rhododendron, with a high sampling density from the Himalaya-Hengduan Mountains employing three analytical methods. The varied approaches (nj, pwg and blast) had different species identification powers with blast performing best. With the pwg analysis, the discrimination rates for single barcodes varied from 12.21% to 25.19% with ITS < rbcL < matK < psbA-trnH. Combinations of ITS + psbA-trnH + matK and the four barcodes showed the highest discrimination ability (both 41.98%) among all possible combinations. As a single barcode, psbA-trnH performed best with a relatively high performance (25.19%). Overall, the three-marker combination of ITS + psbA-trnH + matK was found to be the best DNA barcode for identifying Rhododendron species. The relatively low discriminative efficiency of DNA barcoding in this genus (~42%) may possibly be attributable to too low sequence divergences as a result of a long generation time of Rhododendron and complex speciation patterns involving recent radiations and hybridizations. Taking the morphology, distribution range and habitat of the species into account, DNA barcoding provided additional information for species identification and delivered a preliminary assessment of biodiversity for the large genus Rhododendron in the biodiversity hotspots of the Himalaya-Hengduan Mountains.

  6. Combined hot-spot stress procedures for tubular joints

    SciTech Connect

    Buitrayo, J.; Kahlich, J.L.; Zettlemoyer, N.

    1984-05-01

    An alternative procedure for predicting the combined hot-spot stress (CHSS) at tubular K and Y joints under combined branch loading is presented. The procedure makes use of influence factor (IF) equations developed, as a function of the joint geometry and branch loading, for various potential hot-spot locations on the branch and chord sides of the weld. The CHSS is obtained by lineraly superimposing, at a point, the effects of the axial force and bending moments acting on each branch. The resulting CHSS, therefore, reflects location, orientation and sign of each branch load contribution. Comparisons of predicted CHSS obtained via the new and other procedures to stresses from finite element analyses were made on a large sample of joints. Result show that (1) the new procedure is substantially more reliable than the other procedures studied, (2) none of the procedures consistently predicts conservative CHSS values, and (3) the overriding factor influencing the accuracy of the CHSS calculations appears to be the accuracy of the parametric equations. Although a better stress predictor can be expected to yield more reliable fatigue damage estimates, damage calculations will exhibit broad scatter due to the power function relating damage to stress. Unfortunately, further improvements in the accuracy of CHSS based on parametric equations are not likely to be easily achieved, given the large number of variables and locations that need to be considered.

  7. Content-based analysis of Ki-67 stained meningioma specimens for automatic hot-spot selection.

    PubMed

    Swiderska-Chadaj, Zaneta; Markiewicz, Tomasz; Grala, Bartlomiej; Lorent, Malgorzata

    2016-10-07

    Hot-spot based examination of immunohistochemically stained histological specimens is one of the most important procedures in pathomorphological practice. The development of image acquisition equipment and computational units allows for the automation of this process. Moreover, a lot of possible technical problems occur in everyday histological material, which increases the complexity of the problem. Thus, a full context-based analysis of histological specimens is also needed in the quantification of immunohistochemically stained specimens. One of the most important reactions is the Ki-67 proliferation marker in meningiomas, the most frequent intracranial tumour. The aim of our study is to propose a context-based analysis of Ki-67 stained specimens of meningiomas for automatic selection of hot-spots. The proposed solution is based on textural analysis, mathematical morphology, feature ranking and classification, as well as on the proposed hot-spot gradual extinction algorithm to allow for the proper detection of a set of hot-spot fields. The designed whole slide image processing scheme eliminates such artifacts as hemorrhages, folds or stained vessels from the region of interest. To validate automatic results, a set of 104 meningioma specimens were selected and twenty hot-spots inside them were identified independently by two experts. The Spearman rho correlation coefficient was used to compare the results which were also analyzed with the help of a Bland-Altman plot. The results show that most of the cases (84) were automatically examined properly with two fields of view with a technical problem at the very most. Next, 13 had three such fields, and only seven specimens did not meet the requirement for the automatic examination. Generally, the Automatic System identifies hot-spot areas, especially their maximum points, better. Analysis of the results confirms the very high concordance between an automatic Ki-67 examination and the expert's results, with a Spearman

  8. Automatic layout feature extraction for lithography hotspot detection based on deep neural network

    NASA Astrophysics Data System (ADS)

    Matsunawa, Tetsuaki; Nojima, Shigeki; Kotani, Toshiya

    2016-03-01

    Lithography hotspot detection in the physical verification phase is one of the most important techniques in today's optical lithography based manufacturing process. Although lithography simulation based hotspot detection is widely used, it is also known to be time-consuming. To detect hotspots in a short runtime, several machine learning based methods have been proposed. However, it is difficult to realize highly accurate detection without an increase in false alarms because an appropriate layout feature is undefined. This paper proposes a new method to automatically extract a proper layout feature from a given layout for improvement in detection performance of machine learning based methods. Experimental results show that using a deep neural network can achieve better performance than other frameworks using manually selected layout features and detection algorithms, such as conventional logistic regression or artificial neural network.

  9. Hot-spot mix in ignition-scale inertial confinement fusion targets

    DOE PAGES

    Regan, S. P.; Epstein, R.; Hammel, B. A.; ...

    2013-07-22

    Mixing of plastic ablator material, doped with Cu and Ge dopants, deep into the hot spot of ignition-scale inertial confinement fusion implosions by hydrodynamic instabilities is diagnosed with x-ray spectroscopy on the National Ignition Facility. The amount of hot-spot mix mass is determined from the absolute brightness of the emergent Cu and Ge K-shell emission. The Cu and Ge dopants placed at different radial locations in the plastic ablator show the ablation-front hydrodynamic instability is primarily responsible for hot-spot mix. As a result, low neutron yields and hot-spot mix mass between 34(–13,+50) ng and 4000(–2970,+17 160) ng are observed.

  10. Research on Hotspot Discovery in Internet Public Opinions Based on Improved K-Means

    PubMed Central

    2013-01-01

    How to discover hotspot in the Internet public opinions effectively is a hot research field for the researchers related which plays a key role for governments and corporations to find useful information from mass data in the Internet. An improved K-means algorithm for hotspot discovery in internet public opinions is presented based on the analysis of existing defects and calculation principle of original K-means algorithm. First, some new methods are designed to preprocess website texts, select and express the characteristics of website texts, and define the similarity between two website texts, respectively. Second, clustering principle and the method of initial classification centers selection are analyzed and improved in order to overcome the limitations of original K-means algorithm. Finally, the experimental results verify that the improved algorithm can improve the clustering stability and classification accuracy of hotspot discovery in internet public opinions when used in practice. PMID:24106496

  11. Research on hotspot discovery in internet public opinions based on improved K-means.

    PubMed

    Wang, Gensheng

    2013-01-01

    How to discover hotspot in the Internet public opinions effectively is a hot research field for the researchers related which plays a key role for governments and corporations to find useful information from mass data in the Internet. An improved K-means algorithm for hotspot discovery in internet public opinions is presented based on the analysis of existing defects and calculation principle of original K-means algorithm. First, some new methods are designed to preprocess website texts, select and express the characteristics of website texts, and define the similarity between two website texts, respectively. Second, clustering principle and the method of initial classification centers selection are analyzed and improved in order to overcome the limitations of original K-means algorithm. Finally, the experimental results verify that the improved algorithm can improve the clustering stability and classification accuracy of hotspot discovery in internet public opinions when used in practice.

  12. Results of radiation test of the cathode front-end board for CMS endcap muon chambers

    NASA Astrophysics Data System (ADS)

    Breedon, R.; Bylsma, B.; Durkin, L. S.; Gilmore, J.; Gu, J.; Hauser, J.; Holbrook, B.; Kim, C. L.; Ling, T. Y.; von der Mey, M.; Murray, P.; Rush, C. J.; Santiard, J. C.; Tripathi, M.

    2001-10-01

    After a brief overview of the CMS EMU electronics system, results on radiation induced single event effects, total ionization dose and displacement effects will be reported. These results are obtained by irradiating the components on electronics boards with 63 MeV protons and 1 MeV neutrons. During the proton irradiation, the electronics board was fully under power, all components on the board were active and the data were read out in the same way as designed for CMS. No deterioration of analog performance for each of the three CMOS ASICs on the tested board was observed, up to a dose of 10 krad. Each of the tested FPGAs survived beyond the dose of 30 krad. No single event latch-up was detected for the CMOS ASICs up to a proton fluence of 2×10 12 cm-2. Single Event Upsets (SEU) in FPGAs were detected and their cross-sections measured. SEU mitigation with triple module redundancy and voting was implemented and tested.

  13. The WCRP/GEWEX Surface Radiation Budget Project Release 2: First Results at 1 Degree Resolution

    NASA Technical Reports Server (NTRS)

    Stackhouse, Paul W., Jr.; Cox, Stephen J.; Gupta, Shashi K.; DiPasquale, Roberta C.; Brown, Donald E.

    1999-01-01

    The earth s surface radiative budget in the solar wavelengths (i.e., shortwave) and thermal infrared wavelengths (i.e., longwave) is an important component of Earth s global energy balance and climate. As such, it was identified as a priority need by the World Climate Research Programme (WCRP) and thus a program was instituted at NASA to estimate the radiative flux quantities at the surface from space observations. The Surface Radiation Budget (SRB) Project was created and later included as a component of the Global Energy and Water Cycle Experiment (GEWEX) under the auspices of the WCRP.

  14. Handbook of the Radiation Regime of the Arctic Basin: Results from the Drift Stations

    NASA Technical Reports Server (NTRS)

    Mishin, A. A.; Marshunova, M. S.; Radionov, V. F. (Editor); Colony, R. (Editor)

    1994-01-01

    This Handbook summarizes the radiation data from the Soviet 'North Pole' drifting research stations operated in the Arctic from 1950 to 1991. The Handbook contains reduced mean monthly values of the fluxes of solar radiation for solar elevations up to 35 deg at 5 deg intervals, monthly totals of the net radiation and its constituents, and mean monthly values of the albedo of the sea-ice surfaces. The Handbook presents information of interest to specialists studying the physics of the atmosphere, climatology, geography, and related disciplines.

  15. Prejudice and Health Anxiety about Radiation Exposure from Second-Generation Atomic Bomb Survivors: Results from a Qualitative Interview Study.

    PubMed

    Kamite, Yuka

    2017-01-01

    The effect of atomic bomb radiation exposure on the survivors and their children has been a worrisome problem since soon after the 1945 Hiroshima and Nagasaki bombings. Researchers have examined physical and genetic effects; however, no research has focused on second-generation survivors' (SGS) psychological effects. Consequently, this study shed light on the SGS' experience of discrimination and prejudice and their anxiety concerning the genetic effects of radiation exposure. This study utilized semi-structured interviews with 14 SGS (10 women, mean age = 56 ± 6.25 years, range = 46-68 years). Data were analyzed using a modified version of the grounded theory approach. Three categories were extracted: low awareness as an SGS, no health anxiety regarding the effect of radiation, and health anxiety regarding the effect of radiation. The results did not reveal that SGS who grew up in the bombed areas experienced discrimination or prejudice. They had little health anxiety from childhood to adolescence. In this study, some of the SGS developed health anxiety about their third-generation children, but only among female participants. Perhaps the transgenerational transmission of anxiety concerning the genetic effects of radiation exposure causes stress, particularly among women with children. However, a change was seen in adulthood health anxiety regarding the effects of radiation, suggesting the possibility that changes in the psychological experiences of SGS can be observed throughout their lifetimes and that their own health status, and that of their children, the third-generation survivors, affects their health anxiety regarding radiation.

  16. Prejudice and Health Anxiety about Radiation Exposure from Second-Generation Atomic Bomb Survivors: Results from a Qualitative Interview Study

    PubMed Central

    Kamite, Yuka

    2017-01-01

    The effect of atomic bomb radiation exposure on the survivors and their children has been a worrisome problem since soon after the 1945 Hiroshima and Nagasaki bombings. Researchers have examined physical and genetic effects; however, no research has focused on second-generation survivors’ (SGS) psychological effects. Consequently, this study shed light on the SGS’ experience of discrimination and prejudice and their anxiety concerning the genetic effects of radiation exposure. This study utilized semi-structured interviews with 14 SGS (10 women, mean age = 56 ± 6.25 years, range = 46–68 years). Data were analyzed using a modified version of the grounded theory approach. Three categories were extracted: low awareness as an SGS, no health anxiety regarding the effect of radiation, and health anxiety regarding the effect of radiation. The results did not reveal that SGS who grew up in the bombed areas experienced discrimination or prejudice. They had little health anxiety from childhood to adolescence. In this study, some of the SGS developed health anxiety about their third-generation children, but only among female participants. Perhaps the transgenerational transmission of anxiety concerning the genetic effects of radiation exposure causes stress, particularly among women with children. However, a change was seen in adulthood health anxiety regarding the effects of radiation, suggesting the possibility that changes in the psychological experiences of SGS can be observed throughout their lifetimes and that their own health status, and that of their children, the third-generation survivors, affects their health anxiety regarding radiation. PMID:28912738

  17. Radiation testing campaign results for understanding the suitability of FPGAs in detector electronics

    SciTech Connect

    Citterio, M.; Camplani, A.; Cannon, M.; Chen, H.; Chen, K.; Deng, B.; Liu, C.; Meroni, C.; Kierstead, J.; Takai, H.; Wirthlin, M.; Ye, J.

    2015-11-19

    SRAM based Field Programmable Gate Arrays (FPGAs) have been rarely used in High Energy Physics (HEP) due to their sensitivity to radiation. The last generation of commercial FPGAs based on 28 nm feature size and on Silicon On Insulator (SOI) technologies are more tolerant to radiation to the level that their use in front-end electronics is now feasible. FPGAs provide re-programmability, high-speed computation and fast data transmission through the embedded serial transceivers. They could replace custom application specific integrated circuits in front end electronics in locations with moderate radiation field. Finally, the use of a FPGA in HEP experiments is only limited by our ability to mitigate single event effects induced by the high energy hadrons present in the radiation field.

  18. Radiation testing campaign results for understanding the suitability of FPGAs in detector electronics

    DOE PAGES

    Citterio, M.; Camplani, A.; Cannon, M.; ...

    2015-11-19

    SRAM based Field Programmable Gate Arrays (FPGAs) have been rarely used in High Energy Physics (HEP) due to their sensitivity to radiation. The last generation of commercial FPGAs based on 28 nm feature size and on Silicon On Insulator (SOI) technologies are more tolerant to radiation to the level that their use in front-end electronics is now feasible. FPGAs provide re-programmability, high-speed computation and fast data transmission through the embedded serial transceivers. They could replace custom application specific integrated circuits in front end electronics in locations with moderate radiation field. Finally, the use of a FPGA in HEP experiments ismore » only limited by our ability to mitigate single event effects induced by the high energy hadrons present in the radiation field.« less

  19. Radiation testing campaign results for understanding the suitability of FPGAs in detector electronics

    NASA Astrophysics Data System (ADS)

    Citterio, M.; Camplani, A.; Cannon, M.; Chen, H.; Chen, K.; Deng, B.; Liu, C.; Meroni, C.; Kierstead, J.; Takai, H.; Wirthlin, M.; Ye, J.

    2016-07-01

    SRAM based Field Programmable Gate Arrays (FPGAs) have been rarely used in High Energy Physics (HEP) due to their sensitivity to radiation. The last generation of commercial FPGAs based on 28 nm feature size and on Silicon On Insulator (SOI) technologies are more tolerant to radiation to the level that their use in front-end electronics is now feasible. FPGAs provide re-programmability, high-speed computation and fast data transmission through the embedded serial transceivers. They could replace custom application specific integrated circuits in front end electronics in locations with moderate radiation field. The use of a FPGA in HEP experiments is only limited by our ability to mitigate single event effects induced by the high energy hadrons present in the radiation field.

  20. Results of the radiological survey at the Space Radiation Effects Laboratory, Newport News, Virginia

    SciTech Connect

    Yalcintas, M.G.

    1986-08-01

    The Space Radiation Effects Laboratory located in Newport News, Virginia, was operated by the College of William and Mary for the National Aeronautics and Space Administration (NASA). A synchrocyclotron was formerly in operation in this laboratory and a primary beam of 600 MeV protons and secondary beams of 400 MeV pions and muons were produced for the purpose of studying the effects of radiation on materials planned for use in space. The synchrocyclotron was removed in 1980. At several locations, the scattered radiation caused an induced radioactivity within the walls of the cyclotron room. A radiological survey has been performed to determine the amount of residual radioactivity on the walls. Calculations were performed to determine the thickness of the concrete walls and floor for shielding the residual radiation in the cyclotron room. Recommendations were made to minimize exposure to a potential occupant working in the building from the residual radioactivity on the walls and floor of the cyclotron room.

  1. Report: Results of Technical Network Vulnerability Assessment: EPA’s Radiation and Indoor Environments National Laboratory

    EPA Pesticide Factsheets

    Report #09-P-0053, December 9, 2008. Vulnerability testing of EPA’s Radiation and Indoor Environments National Laboratory (R&IEN) network identified Internet Protocol addresses with medium-risk vulnerabilities.

  2. Hotspot cooling with jumping-drop vapor chambers

    NASA Astrophysics Data System (ADS)

    Wiedenheft, Kris F.; Guo, H. Alex; Qu, Xiaopeng; Boreyko, Jonathan B.; Liu, Fangjie; Zhang, Kungang; Eid, Feras; Choudhury, Arnab; Li, Zhihua; Chen, Chuan-Hua

    2017-04-01

    Hotspot cooling is critical to the performance and reliability of electronic devices, but existing techniques are not very effective in managing mobile hotspots. We report a hotspot cooling technique based on a jumping-drop vapor chamber consisting of parallel plates of a superhydrophilic evaporator and a superhydrophobic condenser, where the working fluid is returned via the spontaneous out-of-plane jumping of condensate drops. While retaining the passive nature of traditional vapor-chamber heat spreaders (flat-plate heat pipes), the jumping-drop technique offers a mechanism to address mobile hotspots with a pathway toward effective thermal transport in the out-of-plane direction.

  3. Hotspot monitoring system with contour-based metrology

    NASA Astrophysics Data System (ADS)

    Kawamoto, A.; Tanaka, Y.; Tsuda, S.; Shibayama, K.; Furukawa, S.; Abe, H.; Mitsui, T.; Yamazaki, Y.

    2009-03-01

    As design rules shrink, hotspot management is becoming increasingly important. In this paper, an automatic system of hotspot monitoring that is the final step in the hotspot management flow is proposed. The key technology for the automatic hotspot monitoring is contour-based metrology. It is an effective method of evaluating complex patterns, such as hotspots, whose efficiency has been proved in the field of optical proximity correction (OPC) calibration. The contour-based metrology is utilized in our system as a process control tool available on mass-production lines. The pattern evaluation methodology has been developed in order to achieve high sensitivity. Lithography simulation decides a hotspot to be monitored and furthermore indicates the most sensitive points in the field of view (FOV) of a hotspot image. And quantification of the most sensitive points is consistent with an engineer's visual check of a shape of a hotspot. Its validity has been demonstrated in process window determination. This system has the potential to substantially shorten turnaround time (TAT) for hotspot monitoring.

  4. Slab fragmentation, edge flow and the origin of the Yellowstone hotspot track

    NASA Astrophysics Data System (ADS)

    James, David E.; Fouch, Matthew J.; Carlson, Richard W.; Roth, Jeffrey B.

    2011-11-01

    The Snake River Plain/Yellowstone (SRP/Y) volcanic province is widely considered a classic example of a plume generated continental hotspot. Here we present new S-wave and P-wave tomographic images that suggest an alternative subduction-related process by which volcanism along the SRP/Y hotspot track results from slab fragmentation, trench retreat, and mantle upwelling at the tip and around the truncated edges of the descending plate. Our seismic images of the upper mantle in the depth range 300-600 km show that the subducted oceanic plate extends locally eastward well into the mantle beneath stable North America. The break-up and along-strike fragmentation of the descending plate is related in both time and space to the onset of flood volcanism and the formation of the SRP/Y hotspot. A sub-horizontal branch of the subducting oceanic plate, orphaned from the descending plate by the northward migration of the Mendocino triple junction, resides in the mantle transition zone (400-600 km) directly beneath the SRP/Y track. Its truncated northern edge is parallel to the northwestern margin of the hotspot track and marks the southern edge of a slab gap. A number of recent numerical and physical tank model studies suggest that a rapidly retreating and severely fragmented downgoing plate drives mantle flow around both the tip and the edges of the descending slab. Our seismic results show that the morphology of the subducting slab is appropriate for generating large-scale poloidal flow (producing flood volcanism) in the upper mantle during the re-initiation phase of slab descent ca 20 Ma and for generating smaller-scale toroidal and poloidal upwellings (producing hotspot volcanism) around both the leading tip and northern edge of the slab as it descends into the deeper upper mantle. Plate reconstructions are consistent with the timing and position of both flood and hotspot volcanism.

  5. Hotspot quantification of myocardial focal tracer uptake from molecular targeted SPECT/CT images: experimental validation

    NASA Astrophysics Data System (ADS)

    Liu, Yi-Hwa; Sahul, Zakir; Weyman, Christopher A.; Ryder, William J.; Dione, Donald P.; Dobrucki, Lawrence W.; Mekkaoui, Choukri; Brennan, Matthew P.; Hu, Xiaoyue; Hawley, Christi; Sinusas, Albert J.

    2008-03-01

    We have developed a new single photon emission computerized tomography (SPECT) hotspot quantification method incorporating extra cardiac activity correction and hotspot normal limit estimation. The method was validated for estimation accuracy of myocardial tracer focal uptake in a chronic canine model of myocardial infarction (MI). Dogs (n = 4) at 2 weeks post MI were injected with Tl-201 and a Tc-99m-labeled hotspot tracer targeted at matrix metalloproteinases (MMPs). An external point source filled with Tc-99m was used for a reference of absolute radioactivity. Dual-isotope (Tc-99m/Tl-201) SPECT images were acquired simultaneously followed by an X-ray CT acquisition. Dogs were sacrificed after imaging for myocardial gamma well counting. Images were reconstructed with CT-based attenuation correction (AC) and without AC (NAC) and were quantified using our quantification method. Normal limits for myocardial hotspot uptake were estimated based on 3 different schemes: maximum entropy, meansquared-error minimization (MSEM) and global minimization. Absolute myocardial hotspot uptake was quantified from SPECT images using the normal limits and compared with well-counted radioactivity on a segment-by-segment basis (n = 12 segments/dog). Radioactivity was expressed as % injected dose (%ID). There was an excellent correlation (r = 0.78-0.92) between the estimated activity (%ID) derived using the SPECT quantitative approach and well-counting, independent of AC. However, SPECT quantification without AC resulted in the significant underestimation of radioactivity. Quantification using SPECT with AC and the MSEM normal limit yielded the best results compared with well-counting. In conclusion, focal myocardial "hotspot" uptake of a targeted radiotracer can be accurately quantified in vivo using a method that incorporates SPECT imaging with AC, an external reference, background scatter compensation, and a suitable normal limit. This hybrid SPECT/CT approach allows for the serial

  6. Breaking and Moving Hotspots in a Large Grain Nb Cavity with a Laser Beam

    SciTech Connect

    Ciovati, G.; Cheng, G.; Flood, R. J.; Jordan, K.; Kneisel, P.; Morrone, M. L.; Turlington, L.; Wilson, K. M.; Zhang, S.; Anlage, S. M.; Gurevich, A. V.; Nemes, G.; Baldwin, C.

    2011-07-25

    Magnetic vortices pinned near the inner surface of SRF Nb cavities are a possible source of RF hotspots, frequently observed by temperature mapping of the cavities outer surface at RF surface magnetic fields of about 100 mT. Theoretically, we expect that the thermal gradient provided by a 10 W green laser shining on the inner cavity surface at the RF hotspot locations can move pinned vortices to different pinning locations. The experimental apparatus to send the beam onto the inner surface of a photoinjector-type large-grain Nb cavity is described. Preliminary results on the changes in thermal maps observed after applying the laser heating are also reported.

  7. Accurate lithography hotspot detection based on PCA-SVM classifier with hierarchical data clustering

    NASA Astrophysics Data System (ADS)

    Gao, Jhih-Rong; Yu, Bei; Pan, David Z.

    2014-03-01

    As technology nodes continues shrinking, layout patterns become more sensitive to lithography processes, resulting in lithography hotspots that need to be identified and eliminated during physical verification. In this paper, we propose an accurate hotspot detection approach based on PCA (principle component analysis)-SVM (sup- port vector machine) classifier. Several techniques, including hierarchical data clustering, data balancing, and multi-level training, are provided to enhance performance of the proposed approach. Our approach is accurate and more efficient than conventional time-consuming lithography simulation; in the meanwhile, provides high flexibility to adapt to new lithography processes and rules.

  8. Late radiation responses in man: current evaluation from results from Hiroshima and Nagasaki.

    PubMed

    Schull, W J

    1983-01-01

    Among the late effects of exposure to the atomic bombings of Hiroshima and Nagasaki, none looms larger than radiation related malignancies. Indeed, the late effects of A-bomb radiation on mortality appear to be limited to an increase in malignant tumors. At present, it can be shown that cancers of the breast, colon, esophagus, lungs, stomach, thyroid, and urinary tract as well as leukemia and multiple myeloma increase in frequency with an increase in exposure. No significant relationship to radiation can as yet be established for malignant lymphoma, nor cancers of the rectum, pancreas or uterus. Radiation induced malignancies other than leukemia seem to develop proportionally to the natural cancer rate for the attained age. For specific age-at-death intervals, both relative and absolute risks tend to be higher for those of younger age at the time of bombing. Other late effects include radiation-related lenticular opacities, disturbances of growth among those survivors still growing at the time of exposure, and mental retardation and small head sizes among the in utero exposed. Chromosomal abnormalities too are more frequently encountered in the peripheral leukocytes of survivors, and this increase is functionally related to their exposure. Some uncertainty continues to surround both the quantity and quality of the radiation released by these two nuclear devices, particularly the Hiroshima bomb. A recent reassessment suggests that the gamma radiation estimates which have been used in the past may be too low at some distances and the neutron radiation estimates too high at all distances; moreover, the energies of the neutrons released now appear "softer" than previously conjectured. These uncertainties are not sufficiently large, however, to compromise the reality of the increased frequency of malignancy, but make estimates of the dose response, particularly in terms of gamma and neutron exposures, tentative.

  9. Risk of secondary malignancies after radiation therapy for breast cancer: Comprehensive results.

    PubMed

    Burt, Lindsay M; Ying, Jian; Poppe, Matthew M; Suneja, Gita; Gaffney, David K

    2017-10-01

    To assess risks of secondary malignancies in breast cancer patients who received radiation therapy compared to patients who did not. The SEER database was used to identify females with a primary diagnosis of breast cancer as their first malignancy, during 1973-2008. We excluded patients with metastatic disease, age <18 years, no definitive surgical intervention, ipsilateral breast cancer recurrence, or who developed a secondary malignancy within 1 year of diagnosis. Standardized incidence ratios and absolute excess risk were calculated using SEER*Stat, version 8.2.1 and SAS, version 9.4. There were 374,993 patients meeting the inclusion criteria, with 154,697 who received radiation therapy. With a median follow-up of 8.9 years, 13% of patients (49,867) developed a secondary malignancy. The rate of secondary malignancies was significantly greater than the endemic rate in breast cancer patients treated without radiation therapy, (O/E 1.2, 95% CI 1.19-1.22) and with radiation therapy (O/E 1.33, 95% CI 1.31-1.35). Approximately 3.4% of secondary malignancies were attributable to radiation therapy. The increased risk of secondary malignancies in breast cancer patients treated with radiation therapy compared to those without was significant regardless of age at breast cancer diagnosis (p < 0.01) and more pronounced with longer latency periods. There was an increased risk of secondary malignancies for breast cancer patients both with and without radiation therapy compared to the general population. There was an increased risk in specific sites for patients treated with radiation therapy. This risk was most evident in young patients and who had longer latency periods. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Late radiation responses in man: Current evaluation from results from Hiroshima and Nagasaki

    NASA Astrophysics Data System (ADS)

    Schull, William J.

    Among the late effects of exposure to the atomic bombings of Hiroshima and Nagasaki, none looms larger than radiation related malignancies. Indeed, the late effects of A-bomb radiation on mortality appear to be limited to an increase in malignant tumors. At present, it can be shown that cancers of the breast, colon, esophagus, lungs, stomach, thyroid, and urinary tract as well as leukemia and multiple myeloma increase in frequency with an increase in exposure. No significant relationship to radiation can as yet be established for malignant lymphoma, nor cancers of the rectum, pancreas or uterus. Radiation induced malignancies other than leukemia seem to develop proportionally to the natural cancer rate for the attained age. For specific age-at-death intervals, both relative and absolute risks tend to be higher for those of younger age at the time of bombing. Other late effects include radiation-related lenticular opacities, disturbances of growth among those survivors still growing at the time of exposure, and mental retardation and small head sizes among the in utero exposed. Chromosomal abnormalities too are more frequently encountered in the peripheral leucocytes of survivors, and this increase is functionally related to their exposure. Some uncertainty continues to surround both the quantity and quality of the radiation released by these two nuclear devices, particularly the Hiroshima bomb. A recent reassessment suggests that the gamma radiation estimates which have been used in the past may be too low at some distances and the neutron radiation estimates too high at all distances; moreover, the energies of the neutrons released now appear ``softer'' than previously conjectured. These uncertainties not sufficiently large, however, to compromise the reality of the increased frequency of malignancy, but make estimates of the dose response, particularly in terms of gamma and neutron exposures, tentative.

  11. Can we detect oceanic biodiversity hotspots from space?

    PubMed

    De Monte, Silvia; Soccodato, Alice; Alvain, Séverine; d'Ovidio, Francesco

    2013-10-01

    Understanding the variability of marine biodiversity is a central issue in microbiology. Current observational programs are based on in situ studies, but their implementation at the global scale is particularly challenging, owing to the ocean extent, its temporal variability and the heterogeneity of the data sources on which compilations are built. Here, we explore the possibility of identifying phytoplanktonic biodiversity hotspots from satellite. We define a Shannon entropy index based on patchiness in ocean color bio-optical anomalies. This index provides a high resolution (1 degree) global coverage. It shows a relation to temperature and mid-latitude maxima in accordance with those previously evidenced in microbiological biodiversity model and observational studies. Regional maxima are in remarkable agreement with several known biodiversity hotspots for plankton organisms and even for higher levels of the marine trophic chain, as well as with some in situ planktonic biodiversity estimates (from Atlantic Meridional Transect cruise). These results encourage to explore marine biodiversity with a coordinated effort of the molecular, ecological and remote sensing communities.

  12. Plant diversity hotspots in the Atlantic coastal forests of Brazil.

    PubMed

    Murray-Smith, Charlotte; Brummitt, Neil A; Oliveira-Filho, Ary T; Bachman, Steven; Moat, Justin; Lughadha, Eimear M Nic; Lucas, Eve J

    2009-02-01

    Plant-diversity hotspots on a global scale are well established, but smaller local hotspots within these must be identified for effective conservation of plants at the global and local scales. We used the distributions of endemic and endemic-threatened species of Myrtaceae to indicate areas of plant diversity and conservation importance within the Atlantic coastal forests (Mata Atlântica) of Brazil. We applied 3 simple, inexpensive geographic information system (GIS) techniques to a herbarium specimen database: predictive species-distribution modeling (Maxent); complementarity analysis (DIVA-GIS); and mapping of herbarium specimen collection locations. We also considered collecting intensity, which is an inherent limitation of use of natural history records for biodiversity studies. Two separate areas of endemism were evident: the Serra do Mar mountain range from Paraná to Rio de Janeiro and the coastal forests of northern Espírito Santo and southern Bahia. We identified 12 areas of approximately 35 km(2) each as priority areas for conservation. These areas had the highest species richness and were highly threatened by urban and agricultural expansion. Observed species occurrences, species occurrences predicted from the model, and results of our complementarity analysis were congruent in identifying those areas with the most endemic species. These areas were then prioritized for conservation importance by comparing ecological data for each.

  13. What, When, Where, and Why of Secondary Hawaiian Hotspot Volcanism

    NASA Astrophysics Data System (ADS)

    Garcia, M. O.; Ito, G.; Applegate, B.; Weis, D.; Swinnard, L.; Flinders, A.; Hanano, D.; Nobre-Silva, I.; Bianco, T.; Naumann, T.; Geist, D.; Blay, C.; Sciaroni, L.; Maerschalk, C.; Harpp, K.; Christensen, B.

    2007-12-01

    Secondary hotspot volcanism occurs on most oceanic island groups (Hawaii, Canary, Society) but its origins remain enigmatic. A 28-day marine expedition used multibeam bathymetry and acoustic imagery to map the extent of submarine volcanic fields around the northern Hawaiian Islands (Kauai, Niihau and Kaula), and the JASON2 ROV to sample many volcanoes to characterize the petrology, geochemistry (major and trace elements, and isotopes) and ages of the lavas from these volcanoes. Our integrated geological, geochemical and geophysical study attempts to examine the what (compositions and source), where (distribution and volumes), when (ages), and why (mechanisms) of secondary volcanism on and around the northern Hawaiian Islands. A first-order objective was to establish how the submarine volcanism relates in space, time, volume, and composition to the nearby shield volcanoes and their associated onshore secondary volcanism. Our surveying and sampling revealed major fields of submarine volcanoes extending from the shallow slopes of these islands to more than 100 km offshore. These discoveries dramatically expand the volumetric importance, distribution and geodynamic framework for Hawaiian secondary volcanism. New maps and rock petrology on the samples collected will be used to evaluate currently proposed mechanisms for secondary volcanism and to consider new models such as small-scale mantle convection driven by thermal and melt-induced buoyancy to produce the huge volume of newly discovered lava. Our results seem to indicate substantial revisions are needed to our current perceptions of hotspot dynamics for Hawaii and possibly elsewhere.

  14. Hotspots, polar wander, Mesozoic convection and the geoid

    NASA Technical Reports Server (NTRS)

    Anderson, D. L.

    1981-01-01

    The geoid bears little relation to present tectonic features of the earth other than trenches. The Mesozoic supercontinent of Pangea, however, apparently occupied a central position in the Atlantic-African geoid high. This and the equatorial Pacific geoid high contain most of the world's hotspots. The plateaus and rises in the western Pacific formed in the Pacific geoid high and this may have been the early Mesozoic position of Pacifica, the fragments of which are now the Pacific rim portions of the continents. Geoid highs which are unrelated to present subduction zones may be the former sites of continental aggregations and mantle insulation and, therefore, hotter than normal mantle. The pent-up heat causes rifts and hotspots and results in extensive uplift, magmatism, fragmentation and dispersal of the continents and the subsequent formation of plateaus, aseismic ridges and seamount chains. Convection in the uppermantle would then be due to lateral temperature gradients as well as heating from below and would be intrinsically episodic.

  15. Venus: Mantle convection, hotspots, and tectonics

    NASA Technical Reports Server (NTRS)

    Phillips, R. J.

    1989-01-01

    The putative paradigm that planets of the same size and mass have the same tectonic style led to the adaptation of the mechanisms of terrestrial plate tectonics as the a priori model of the way Venus should behave. Data acquired over the last decade by Pioneer Venus, Venera, and ground-based radar have modified this view sharply and have illuminated the lack of detailed understanding of the plate tectonic mechanism. For reference, terrestrial mechanisms are briefly reviewed. Venusian lithospheric divergence, hotspot model, and horizontal deformation theories are proposed and examined.

  16. Hypofractionated Postmastectomy Radiation Therapy Is Safe and Effective: First Results From a Prospective Phase II Trial.

    PubMed

    Khan, Atif J; Poppe, Matthew M; Goyal, Sharad; Kokeny, Kristine E; Kearney, Thomas; Kirstein, Laurie; Toppmeyer, Deborah; Moore, Dirk F; Chen, Chunxia; Gaffney, David K; Haffty, Bruce G

    2017-06-20

    Purpose Conventionally fractionated postmastectomy radiation therapy (PMRT) takes approximately 5 to 6 weeks. Data supporting hypofractionated PMRT is limited. We prospectively evaluated a short course of hypofractionated PMRT, in which therapy was completed in 15 treatment days. Patients and Methods We delivered PMRT at a dose of 36.63 Gy in 11 fractions of 3.33 Gy over 11 days to the chest wall and the draining regional lymph nodes, followed by an optional mastectomy scar boost of four fractions of 3.33 Gy. Our primary end point was freedom from any grade 3 or higher toxicities. We incorporated early stopping criteria on the basis of predefined toxicity thresholds. Results We enrolled 69 women with stage II to IIIa breast cancer, of whom 67 were eligible for analysis. After a median follow-up of 32 months, there were no grade 3 toxicities. There were 29 reported grade 2 toxicities, with grade 2 skin toxicities being the most frequent (16 of 67; 24%). There were two patients with isolated ipsilateral chest wall tumor recurrences (2 of 67; crude rate, 3%). Three-year estimated local recurrence-free survival was 89.2% (95% CI, 0.748 to 0.956). The 3-year estimated distant recurrence-free survival was 90.3% (95% CI, 0.797 to 0.956). Forty-one patients had chest wall reconstructions; three had expanders removed for infection before radiation therapy. The total rate of implant loss or failure was 24% (9 of 38), and the unplanned surgical correction rate was 8% (3 of 38), for a total complication rate of 32%. Conclusion To our knowledge, our phase II prospective study offers one of the shortest courses of PMRT reported, delivered in 11 fractions to the chest wall and nodes and 15 fractions inclusive of a boost. We demonstrated low toxicity and high local control with this schedule. On the basis of our data, we have designed a cooperative group phase III prospective, randomized trial of conventional versus hypofractionated PMRT that will activate soon.

  17. Radiation therapy for seminoma of the testis: results in British Columbia.

    PubMed Central

    Jackson, S M; Olivotto, I; McLoughlin, M G; Coy, P

    1980-01-01

    Between 1942 and 1978 radiation therapy was given to 362 patients with seminoma of the testis, 40 (11%) of whom had a history of maldescent of either testis. The disease was classified retrospectively according to the extent of the primary tumor, the involvement of the regional lymph nodes and the presence of distant metastases (the TNM system), and the results of treatment were analysed according to the classifications. Among the 275 patients referred for treatment at least 5 years before this analysis the 5-year survival rates were 87% overall, 96% for those with a T1 or T2 (relatively localized) tumour but no evidence of nodal involvement or distant metastases and 62% for the 24 with palpable or distant metastases at the time of clinical presentation. Of the 28 patients in whom the disease recurred 15 were successfully treated. A second primary testicular tumour developed in the contralateral testis of eight patients. The incidence of other cancers was not increased over the expected rate in the general male population of the same age. PMID:7437970

  18. Effectiveness of microwave hyperthermia combined with ionizing radiation: clinical results on nieck node metastases

    SciTech Connect

    Arcangeli, G.; Barni, E.; Cividalli, A.; Mauro, F.; Morelli, D.; Nervi, C.; Spano, M.; Tabocchini, A.

    1980-02-01

    Patients with superficial malignant lesions have been treated with local hyperthermia in association with radiation. Heat was applied by means of a newly assembled apparatus with a variable frequency microwave generator (200 to 3000 MHz). The apparatus was operated at a frequency of 500 MHz; heat was delivered with non-contact applicators designed for different surface curvature. Adequate heating for depths up to about 3 cm was demonstrated by isothermal maps in chopped meat phantoms. A group of 15 patients with N/sub 2/-N/sub 3/ multiple cervical nodes from head and neck cancer were treated with a multiple daily fractionation (MDF) radiotherapy, according to our previous clinical experience, and with MDF combined with local hyperthermia. A direct comparison of the two treatments on different nodes was possible for each patient: 17/20 nodes (85%) achieved a complete response with this combined schedule, 6/13 (46%) with MDF alone, and 14/46 (30%) with conventional fractionation (historical series). The same combined treatment also was delivered to a group of 4 patients with other kinds of tumors. Complete or satisfactory responses were also obtained in these patients. The results suggest that MDF can be advantageously combined with local hyperthermia.

  19. New calculations of the atmospheric cosmic radiation field--results for neutron spectra.

    PubMed

    Clem, J M; De Angelis, G; Goldhagen, P; Wilson, J W

    2004-01-01

    The propagation of primary cosmic rays through the Earth's atmosphere and the energy spectra of the resulting secondary particles have been calculated using the Monte Carlo transport code FLUKA with several novel auxiliary methods. Solar-modulated primary cosmic ray spectra were determined through an analysis of simultaneous proton and helium measurements made on spacecraft or high-altitude balloon flights. Primary protons and helium ions are generated within the rigidity range of 0.5 GV-20 TV, uniform in cos2theta. For a given location, primaries above the effective angle-dependent geomagnetic cut-off rigidity, and re-entrant albedo protons, are transported through the atmosphere. Helium ions are initially transported using a separate transport code called HEAVY to simulate fragmentation. HEAVY interfaces with FLUKA to provide interaction starting points for each nucleon originating from a helium nucleus. Calculated cosmic ray neutron spectra and consequent dosimetric quantities for locations with a wide range of altitude (atmospheric depth) and geomagnetic cut-off are presented and compared with measurements made on a high-altitude aeroplane. Helium ion propagation using HEAVY and inclusion of re-entrant albedo protons with the incident primary spectra significantly improved the agreement of the calculated cosmic ray neutron spectra with measured spectra. These cosmic ray propagation calculations provide the basis for a new atmospheric ionising radiation (AIR) model for air-crew dosimetry, calculation of effects on microelectronics, production of cosmogenic radionuclides and other uses.

  20. Design of x-ray diagnostic beam line for a synchrotron radiation source and measurement results

    NASA Astrophysics Data System (ADS)

    Garg, Akash Deep; Karnewar, A. K.; Ojha, A.; Shrivastava, B. B.; Holikatti, A. C.; Puntambekar, T. A.; Navathe, C. P.

    2014-08-01

    Indus-2 is a 2.5 GeV synchrotron radiation source (SRS) operational at the Raja Ramanna Centre for Advanced Technology (RRCAT) in India. We have designed, developed and commissioned x-ray diagnostic beam line (X-DBL) at the Indus-2. It is based on pinhole array imaging (8-18 keV). We have derived new equations for online measurements of source position and emission angle with pinhole array optics. Measured values are compared with the measurements at an independent x-ray beam position monitor (staggered pair blade monitor) installed in the X-DBL. The measured values are close to the theoretical expected values within ±12 μm (or ±1.5 μrad) for sufficiently wide range of the beam movements. So, beside the beam size and the beam emittance, online information for the vertical position and angle is also used in the orbit steering. In this paper, the various design considerations of the X-DBL and online measurement results are presented.

  1. Global Plate Motions Relative to the Hotspots since 48 Ma B.P. from Simultaneous Inversion of Hotspot Tracks in the Pacific, Indian, and Atlantic Oceans Constrained to Consistency with Known Relative Plate Motions

    NASA Astrophysics Data System (ADS)

    Gordon, R. G.; Koivisto, E. A. L.

    2016-12-01

    A fundamental problem of global tectonics and paleomagnetism is determining what part of apparent polar wander is due to plate motion and what part is due to true polar wander. One approach for separating these is available if global hotspots can be used as a reference frame approximately fixed with respect to the deep mantle. Some other workers have used a hotspot reference based only on tracks in the Atlantic and Indian Oceans, and some have used reference frames with moving hotspots and many adjustable parameters. In sharp contrast to the assumptions made in these other works, our recent results demonstrate that there is no significant motion between the Pacific and Indo-Atlantic hotspots since 48 Ma B.P. (lower bound of zero and upper bound of 8-13 mm/yr [Koivisto et al., 2014]). Corrected methodologies combined with cumulative improvements in the age progression along the hotspot tracks, the geomagnetic reversal time scale, and relative plate reconstructions lead to significantly lower rates of motion between hotspots than found in prior studies. Building on our prior results, here we present a globally self-consistent estimate of plate motions relative to the hotspots for the past 48 million years from inversions to fit simultaneously the tracks of the Hawaiian, Louisville, Tristan da Cunha, Réunion, and Iceland hotspots constrained to consistency with known relative plate motions. Each finite rotation is estimated for an age corresponding to a key magnetic anomaly used in plate reconstructions. The new set of plate reconstructions presented here provides a firm basis for estimating absolute plate motions for the past 48 million years and, in particular, can be used to separate paleomagnetically determined apparent polar wander into the part due to plate motion and the part due to true polar wander. Implications for true polar wander since the age of the Hawaiian-Emperor Bend will be discussed.

  2. Current Global Absolute Plate Velocities Inferred from the Trends of Hotspot Tracks: Implications for Motion between Groups of Hotspots and Comparison and Combination with Absolute Velocities Inferred from the Orientation of Seismic Anisotropy

    NASA Astrophysics Data System (ADS)

    Wang, C.; Gordon, R. G.; Zheng, L.

    2016-12-01

    Hotspot tracks are widely used to estimate the absolute velocities of plates, i.e., relative to the lower mantle. Knowledge of current motion between hotspots is important for both plate kinematics and mantle dynamics and informs the discussion on the origin of the Hawaiian-Emperor Bend. Following Morgan & Morgan (2007), we focus only on the trends of young hotspot tracks and omit volcanic propagation rates. The dispersion of the trends can be partitioned into between-plate and within-plate dispersion. Applying the method of Gripp & Gordon (2002) to the hotspot trend data set of Morgan & Morgan (2007) constrained to the MORVEL relative plate angular velocities (DeMets et al., 2010) results in a standard deviation of the 56 hotspot trends of 22°. The largest angular misfits tend to occur on the slowest moving plates. Alternatively, estimation of best-fitting poles to hotspot tracks on the nine individual plates, results in a standard deviation of trends of only 13°, a statistically significant reduction from the introduction of 15 additional adjustable parameters. If all of the between-plate misfit is due to motion of groups of hotspots (beneath different plates), nominal velocities relative to the mean hotspot reference frame range from 1 to 4 mm/yr with the lower bounds ranging from 1 to 3 mm/yr and the greatest upper bound being 8 mm/yr. These are consistent with bounds on motion between Pacific and Indo-Atlantic hotspots over the past ≈50 Ma, which range from zero (lower bound) to 8 to 13 mm/yr (upper bounds) (Koivisto et al., 2014). We also determine HS4-MORVEL, a new global set of plate angular velocities relative to the hotspots constrained to consistency with the MORVEL relative plate angular velocities, using a two-tier analysis similar to that used by Zheng et al. (2014) to estimate the SKS-MORVEL global set of absolute plate velocities fit to the orientation of seismic anisotropy. We find that the 95% confidence limits of HS4-MORVEL and SKS

  3. GAMMA RADIATION INTERACTS WITH MELANIN TO ALTER ITS OXIDATION-REDUCTION POTENTIAL AND RESULTS IN ELECTRIC CURRENT PRODUCTION

    SciTech Connect

    Turick, C.; Ekechukwu, A.; Milliken, C.

    2011-05-17

    The presence of melanin pigments in organisms is implicated in radioprotection and in some cases, enhanced growth in the presence of high levels of ionizing radiation. An understanding of this phenomenon will be useful in the design of radioprotective materials. However, the protective mechanism of microbial melanin in ionizing radiation fields has not yet been elucidated. Here we demonstrate through the electrochemical techniques of chronoamperometry, chronopotentiometry and cyclic voltammetry that microbial melanin is continuously oxidized in the presence of gamma radiation. Our findings establish that ionizing radiation interacts with melanin to alter its oxidation-reduction potential. Sustained oxidation resulted in electric current production and was most pronounced in the presence of a reductant, which extended the redox cycling capacity of melanin. This work is the first to establish that gamma radiation alters the oxidation-reduction behavior of melanin, resulting in electric current production. The significance of the work is that it provides the first step in understanding the initial interactions between melanin and ionizing radiation taking place and offers some insight for production of biomimetic radioprotective materials.

  4. Gamma radiation interacts with melanin to alter its oxidation-reduction potential and results in electric current production.

    PubMed

    Turick, Charles E; Ekechukwu, Amy A; Milliken, Charles E; Casadevall, Arturo; Dadachova, Ekaterina

    2011-08-01

    The presence of melanin pigments in organisms is implicated in radioprotection and in some cases, enhanced growth in the presence of high levels of ionizing radiation. An understanding of this phenomenon will be useful in the design of radioprotective materials. However, the protective mechanism of microbial melanin in ionizing radiation fields has not yet been elucidated. Here we demonstrate through the electrochemical techniques of chronoamperometry, chronopotentiometry and cyclic voltammetry that microbial melanin is continuously oxidized in the presence of gamma radiation. Our findings establish that ionizing radiation interacts with melanin to alter its oxidation-reduction potential. Sustained oxidation resulted in electric current production and was most pronounced in the presence of a reductant, which extended the redox cycling capacity of melanin. This work is the first to establish that gamma radiation alters the oxidation-reduction behavior of melanin, resulting in electric current production. The significance of the work is that it provides the first step in understanding the initial interactions between melanin and ionizing radiation taking place and offers some insight for production of biomimetic radioprotective materials.

  5. Ten-year trends in safe radiation therapy delivery and results of a radiation therapy quality assurance intervention.

    PubMed

    Dominello, Michael M; Paximadis, Peter; Zaki, Mark; Hammoud, Ahmad; Campbell, Shauna; Komajda, Melanie; Dyson, Gregory; Bossenberger, Todd; Burmeister, Jay

    2015-01-01

    This study reviews our institutional error data and assesses the effectiveness of a policy implemented January 1, 2011, as a "no rushed treatment" initiative to avoid universal, large-scale replanning for all patients in the event that a treatment unit is down for ≤1 day. Radiation error data between January 1, 2004, and December 31, 2014, were reviewed to determine absolute delivery error rates. Variables were compared (using a χ(2) or Fisher exact test) before and after the policy change, including planning versus delivery error status and differences in error type. We also evaluated time of day in relation to therapist shift change, deviation from scheduled time, and weekend treatment as predictors of error using a test of proportions or χ(2) test. Treatment delivery error rate over the entire period was 0.18% per fraction; the rate before intervention was 0.24% and after was 0.08%, P < .001. For the 5 years for which detailed records were available (2010-2014), 109 delivery errors were reported. Delivery error rate was 0.09%; before intervention 0.15% versus after, 0.08% (P = .005) and 94% were level 1 errors. Fifty-six percent were primary planning errors and 44% were primary delivery errors. Before intervention, large-scale replanning occurred 18 times/year versus 4.5/year after, with 21% versus 12% of errors directly attributable to large-scale replanning. Fourteen error reports specifically implicated a rushed environment as causal. There was no significant difference in error rate based on time of day (P = .631). Error rates were higher for weekend simulation and treatments, 1.3% versus 0.09% per fraction (P < .001). Delivery error rates at our institution were similar compared with published series from other academic institutions. A significant improvement in delivery error rate was appreciated after implementation of a "no rushed treatment" initiative. A significantly higher error rate for weekend treatments was noted, warranting consideration of

  6. Comparative phylogeography reveals deep lineages and regional evolutionary hotspots in the Mojave and Sonoran Deserts

    USGS Publications Warehouse

    Wood, Dustin A.; Vandergast, Amy G.; Barr, Kelly R.; Inman, Richard D.; Esque, Todd C.; Nussear, Kenneth E.; Fisher, Robert N.

    2013-01-01

    Aim: We explored lineage diversification within desert-dwelling fauna. Our goals were (1) to determine whether phylogenetic lineages and population expansions were consistent with younger Pleistocene climate fluctuation hypotheses or much older events predicted by pre-Pleistocene vicariance hypotheses, (2) to assess concordance in spatial patterns of genetic divergence and diversity among species and (3) to identify regional evolutionary hotspots of divergence and diversity and assess their conservation status. Location: Mojave, Colorado, and Sonoran Deserts, USA. Methods: We analysed previously published gene sequence data for twelve species. We used Bayesian gene tree methods to estimate lineages and divergence times. Within each lineage, we tested for population expansion and age of expansion using coalescent approaches. We mapped interpopulation genetic divergence and intra-population genetic diversity in a GIS to identify hotspots of highest genetic divergence and diversity and to assess whether protected lands overlapped with evolutionary hotspots. Results: In seven of the 12 species, lineage divergence substantially predated the Pleistocene. Historical population expansion was found in eight species, but expansion events postdated the Last Glacial Maximum (LGM) in only four. For all species assessed, six hotspots of high genetic divergence and diversity were concentrated in the Colorado Desert, along the Colorado River and in the Mojave/Sonoran ecotone. At least some proportion of the land within each recovered hotspot was categorized as protected, yet four of the six also overlapped with major areas of human development. Main conclusions: Most of the species studied here diversified into distinct Mojave and Sonoran lineages prior to the LGM – supporting older diversification hypotheses. Several evolutionary hotspots were recovered but are not strategically paired with areas of protected land. Long-term preservation of species-level biodiversity would

  7. Exome-Scale Discovery of Hotspot Mutation Regions in Human Cancer Using 3D Protein Structure.

    PubMed

    Tokheim, Collin; Bhattacharya, Rohit; Niknafs, Noushin; Gygax, Derek M; Kim, Rick; Ryan, Michael; Masica, David L; Karchin, Rachel

    2016-07-01

    The impact of somatic missense mutation on cancer etiology and progression is often difficult to interpret. One common approach for assessing the contribution of missense mutations in carcinogenesis is to identify genes mutated with statistically nonrandom frequencies. Even given the large number of sequenced cancer samples currently available, this approach remains underpowered to detect drivers, particularly in less studied cancer types. Alternative statistical and bioinformatic approaches are needed. One approach to increase power is to focus on localized regions of increased missense mutation density or hotspot regions, rather than a whole gene or protein domain. Detecting missense mutation hotspot regions in three-dimensional (3D) protein structure may also be beneficial because linear sequence alone does not fully describe the biologically relevant organization of codons. Here, we present a novel and statistically rigorous algorithm for detecting missense mutation hotspot regions in 3D protein structures. We analyzed approximately 3 × 10(5) mutations from The Cancer Genome Atlas (TCGA) and identified 216 tumor-type-specific hotspot regions. In addition to experimentally determined protein structures, we considered high-quality structural models, which increase genomic coverage from approximately 5,000 to more than 15,000 genes. We provide new evidence that 3D mutation analysis has unique advantages. It enables discovery of hotspot regions in many more genes than previously shown and increases sensitivity to hotspot regions in tumor suppressor genes (TSG). Although hotspot regions have long been known to exist in both TSGs and oncogenes, we provide the first report that they have different characteristic properties in the two types of driver genes. We show how cancer researchers can use our results to link 3D protein structure and the biologic functions of missense mutations in cancer, and to generate testable hypotheses about driver mechanisms. Our results

  8. Local Hotspots In The Gulf Of Maine: Spatial Overlap Between Dynamic Aggregations Of Primary Productivity And Fish Abundance

    NASA Astrophysics Data System (ADS)

    Ribera, M.

    2016-12-01

    Identification of biological hotspots may be a necessary step toward ecosystem-based management goals, as these often signal underlying processes that aggregate or stimulate resources in a particular location. However, previously used metrics to locate these hotspots are not easily adapted to local marine datasets, in part due to the high spatial and temporal variability of phytoplankton populations. While most fish species in temperate regions are well adapted to the seasonal variability of phytoplankton abundance, it is the variability beyond this predictable pattern (i.e. anomalies) that may heavily impact the abundance and spatial distribution of organisms higher up the food chain. The objective of this study was to identify local-scale biological hotspots in a region in the western side of the Gulf of Maine using remote sensing chlorophyll-a data (from MERIS sensor), and to study the spatial overlap between these hotspots and high concentrations of fish abundance (derived from VTR dataset). For this reason, we defined a new hotspot metric that identified as a hotspot any area that consistently exhibited high-magnitude anomalies through time, a sign of highly dynamic communities. We improved on previous indices by minimizing the effect that different means and variances across space may have on the results, a situation that often occurs when comparing coastal and offshore systems. Results show a significant spatial correlation between pelagic fish abundance and aggregations of primary productivity. Spatial correlations were also significant between benthic fish abundance and primary productivity hotspots, but only during spring months. We argue that this new hotspot index compliments existing global measures as it helps managers understand the dynamic characteristics of a complex marine system. It also provides a unique metric that is easily compared across space and between different trophic levels, which may facilitate future ecosystem-wide studies.

  9. The AMSAT-OSCAR-40 High Elliptical Orbit Radiation Environment Monitoring Payload - First Flight Results

    NASA Astrophysics Data System (ADS)

    Sweeting, Martin, , Sir

    Over the last decade, Surrey's micro-satellites have provided continuous monitoring of the proton and heavy-ion environment encountered in low-Earth orbit (LEO), through the use of a series of silicon PIN-diode-based particle detectors, starting with the UK Defence Evaluation Research Agency's (DERA's) Cosmic-Radiation Environment and Dosimetry (CREDO) payload, flown on-board UoSAT-3 in 1990, followed in 1992 by the Cosmic-Ray Experiment (CRE), developed at the Surrey Space Centre under a micro-satellite Technology Transfer (TT) programme operated between Surrey Satellite Technology Ltd. (SSTL) and the Korea Advanced Institute of Science and Technology (KAIST), and flown on the resulting KITSAT-1 micro-satellite. The CRE was flown again in 1993 on-board the PoSAT- 1 micro-satellite, developed under a similar TT programme operated between SSTL and Portugal. The results from all of these instruments have given a great deal of information on the nature of the low-Earth orbit (LEO) ionising radiation environment, and in the case of the PoSAT-1 CRE, continue to do so. However, to obtain a more complete "picture" of the magnetosphere, it is necessary to orbit instruments much further out in space An opportunity to do this arose in 1994 when amateur radio satellite groups (AMSAT) proposed launching a small (600 kg) communications satellite into highly elliptical orbit. This satellite, called AMSAT-OSCAR-40 (AO-40), was launched by Ariane 5 rocket on 16th November 2000, initially into a geostationary transfer orbit (GTO). The satellite has subsequently been manoeuvred into a highly elliptical, 1070 km x 58,700 km, 6.8o inclination orbit, and thus it affords the opportunity to observe the proton and heavy-ion environment through a large cross-section of Earth's magnetosphere. AO-40 carries a version of the CRE, which has been slightly modified in terms of interfaces and packaging to fit that particular satellite bus. However the particle detecting element is essentially

  10. Monitoring conservation effectiveness in a global biodiversity hotspot: the contribution of land cover change assessment.

    PubMed

    Joseph, Shijo; Blackburn, George Alan; Gharai, Biswadip; Sudhakar, S; Thomas, A P; Murthy, M S R

    2009-11-01

    Tropical forests, which play critical roles in global biogeochemical cycles, radiation budgets and biodiversity, have undergone rapid changes in land cover in the last few decades. This study examines the complex process of land cover change in the biodiversity hotspot of Western Ghats, India, specifically investigating the effects of conservation measures within the Indira Gandhi Wildlife Sanctuary. Current vegetation patterns were mapped using an IRS P6 LISS III image and this was used together with Landsat MSS data from 1973 to map land cover transitions. Two major and divergent trends were observed. A dominant degradational trend can be attributed to agricultural expansion and infrastructure development while a successional trend, resulting from protection of the area, showed the resilience of the system after prolonged disturbances. The sanctuary appears susceptible to continuing disturbances under the current management regime but at lower rates than in surrounding unprotected areas. The study demonstrates that remotely sensed land cover assessments can have important contributions to monitoring land management strategies, understanding processes underpinning land use changes and helping to inform future conservation strategies.

  11. Early Yellowstone hotspot magmatism and gold metallogeny

    NASA Astrophysics Data System (ADS)

    Hames, Willis; Unger, Derick; Saunders, James; Kamenov, George

    2009-11-01

    High-grade epithermal gold deposits in the Northern Great Basin have long been associated with regional Miocene basaltic to rhyolitic volcanism. Previous models for the low-sulfidation epithermal gold ores in this region have generally portrayed the bimodal magmas as a source of heat to drive large-scale convection of meteoritic water that leached gold from crustal sources and deposited it in hydrothermal vein systems, or required that the gold evolve from fractionated silicic magmas. New data of the present study indicate a more direct genetic link to the plume-related basaltic magmas of the region. Laser 40Ar/ 39Ar incremental heating plateau ages for single crystals of adularia from several of these low-sulfidation epithermal gold deposits range from 16.6 Ma to 15.5 Ma. Adularia from the Jumbo deposit yields three concordant plateau ages with a combined statistical result of 16.54 ± 0.04 Ma (95% confidence level, MSWD = 0.23). Plateau ages for adularia from other deposits in the region, and from gold-bearing veins in the Owyhee Mountains of southwestern Idaho, yield similar ages up to ~16.5 Ma, however some veins are as young as ca. 15.5 Ma and the grain-to-grain ages for a given sample can vary by up to ca. 0.5 Ma. Observed variations in age among the adularia crystals of a given rock sample indicate varying amounts of extraneous argon, and also loss of radiogenic 40Ar, among the population of grains for a particular sample. The single-crystal results are interpreted to indicate a 16.5-15.5 Ma interval for formation of gold-bearing adularia veins in the region. The initiation and duration of this gold-forming event appears contemporaneous (within uncertainties) with the basaltic volcanism at the Steens Mountain section and an ensuing one-million-year episode of basaltic volcanism from multiple centers in the region ( Brueseke et al., 2007). Trace amounts of lead are alloyed with gold in the deposits studied. The isotopic compositions of this lead are not

  12. The Value of the Internship for Radiation Oncology Training: Results of a Survey of Current and Recent Trainees

    SciTech Connect

    Baker, Stephen R. Romero, Michelle J. M.A.; Geannette, Christian M.D.; Patel, Amish

    2009-07-15

    Purpose: Although a 12-month clinical internship is the traditional precursor to a radiation oncology residency, the continuance of this mandated training sequence has been questioned. This study was performed to evaluate the perceptions of current radiation oncology residents with respect to the value of their internship experience. Methods and Materials: A survey was sent to all US radiation oncology residents. Each was queried about whether they considered the internship to be a necessary prerequisite for a career as a radiation oncologist and as a physician. Preferences were listed on a Likert scale (1 = not at all necessary to 5 = absolutely necessary). Results: Seventy-one percent considered the internship year mostly (Likert Scale 4) or absolutely necessary (Likert Scale 5) for their development as a radiation oncologist, whereas 19.1% answered hardly or not at all (Likert Scale 2 and 1, respectively). With respect to their collective considerations about the impact of the internship year on their development as a physician, 89% had a positive response, 5.8% had a negative response, and 4.7% had no opinion. Although both deemed the preliminary year favorably, affirmative answers were more frequent among erstwhile internal medicine interns than former transitional program interns. Conclusions: A majority of radiation oncology residents positively acknowledged their internship for their development as a specialist and an even greater majority valued it for their development as a physician. This affirmative opinion was registered more frequently by those completing an internal medicine internship compared with a transitional internship.

  13. Estimating the risks of cancer mortality and genetic defects resulting from exposures to low levels of ionizing radiation

    SciTech Connect

    Buhl, T.E.; Hansen, W.R.

    1984-05-01

    Estimators for calculating the risk of cancer and genetic disorders induced by exposure to ionizing radiation have been recommended by the US National Academy of Sciences Committee on the Biological Effects of Ionizing Radiations, the UN Scientific Committee on the Effects of Atomic Radiation, and the International Committee on Radiological Protection. These groups have also considered the risks of somatic effects other than cancer. The US National Council on Radiation Protection and Measurements has discussed risk estimate procedures for radiation-induced health effects. The recommendations of these national and international advisory committees are summarized and compared in this report. Based on this review, two procedures for risk estimation are presented for use in radiological assessments performed by the US Department of Energy under the National Environmental Policy Act of 1969 (NEPA). In the first procedure, age- and sex-averaged risk estimators calculated with US average demographic statistics would be used with estimates of radiation dose to calculate the projected risk of cancer and genetic disorders that would result from the operation being reviewed under NEPA. If more site-specific risk estimators are needed, and the demographic information is available, a second procedure is described that would involve direct calculation of the risk estimators using recommended risk-rate factors. The computer program REPCAL has been written to perform this calculation and is described in this report. 25 references, 16 tables.

  14. Radiation-induced signaling results in mitochondrial impairment in mouse heart at 4 weeks after exposure to X-rays.

    PubMed

    Barjaktarovic, Zarko; Schmaltz, Dominik; Shyla, Alena; Azimzadeh, Omid; Schulz, Sabine; Haagen, Julia; Dörr, Wolfgang; Sarioglu, Hakan; Schäfer, Alexander; Atkinson, Michael J; Zischka, Hans; Tapio, Soile

    2011-01-01

    Radiation therapy treatment of breast cancer, Hodgkin's disease or childhood cancers expose the heart to high local radiation doses, causing an increased risk of cardiovascular disease in the survivors decades after the treatment. The mechanisms that underlie the radiation damage remain poorly understood so far. Previous data show that impairment of mitochondrial oxidative metabolism is directly linked to the development of cardiovascular disease. In this study, the radiation-induced in vivo effects on cardiac mitochondrial proteome and function were investigated. C57BL/6N mice were exposed to local irradiation of the heart with doses of 0.2 Gy or 2 Gy (X-ray, 200 kV) at the age of eight weeks, the control mice were sham-irradiated. After four weeks the cardiac mitochondria were isolated and tested for proteomic and functional alterations. Two complementary proteomics approaches using both peptide and protein quantification strategies showed radiation-induced deregulation of 25 proteins in total. Three main biological categories were affected: the oxidative phophorylation, the pyruvate metabolism, and the cytoskeletal structure. The mitochondria exposed to high-dose irradiation showed functional impairment reflected as partial deactivation of Complex I (32%) and Complex III (11%), decreased succinate-driven respiratory capacity (13%), increased level of reactive oxygen species and enhanced oxidation of mitochondrial proteins. The changes in the pyruvate metabolism and structural proteins were seen with both low and high radiation doses. This is the first study showing the biological alterations in the murine heart mitochondria several weeks after the exposure to low- and high-dose of ionizing radiation. Our results show that doses, equivalent to a single dose in radiotherapy, cause long-lasting changes in mitochondrial oxidative metabolism and mitochondria-associated cytoskeleton. This prompts us to propose that these first pathological changes lead to an increased

  15. Modifications to population rate equations resulting from correlations between collisional and radiative processes

    NASA Technical Reports Server (NTRS)

    Ballagh, R. J.; Cooper, J.

    1984-01-01

    There are many systems of physical interest for which a set of rate equations for level populations can provide insight. If the system has two (or more) different mechanisms for effecting transition between levels, total rates of transfer are usually taken as the sum of rates that the individual mechanisms would cause acting alone. Using the example of a hydrogen atom subjected to (ionic and electronic) collisions and external radiation, it is shown that when these individual mechanisms overlap, the total transfer rates must be modified to account for correlations between collisional and radiative processes. For a broad-band radiation field the modified rates have a simple physical interpretation. In the case of a narrow-band field the overlapping events may cause new coherences to appear and interpretation of the modified 'rates' is more complicated.

  16. Radiation Protection in Pediatric Radiology: Results of a Survey Among Dutch Hospitals.

    PubMed

    Bijwaard, Harmen; Valk, Doreth; de Waard-Schalkx, Ischa

    2016-10-01

    A survey about radiation protection in pediatric radiology was conducted among 22 general and seven children's hospitals in the Netherlands. Questions concerned, for example, child protocols used for CT, fluoroscopy and x-ray imaging, number of images and scans made, radiation doses and measures taken to reduce these, special tools used for children, and quality assurance issues. The answers received from 27 hospitals indicate that radiation protection practices differ considerably between general and children's hospitals but also between the respective general and children's hospitals. It is recommended that hospitals consult each other to come up with more uniform best practices. Few hospitals were able to supply doses that can be compared to the national Diagnostic Reference Levels (DRLs). The ones that could be compared exceeded the DRLs in one in five cases, which is more than was expected beforehand.

  17. Spectral distortions of the microwave background radiation resulting from the damping of pressure waves

    SciTech Connect

    Daly, R.A. )

    1991-04-01

    Initial perturbations of the energy density of the radiation field associated with initial perturbations of the mass density on scales relevant for galaxies and clusters of galaxies are not observable as anisotropies of the temperature of the microwave background radiation. By the recombination epoch, the initial inhomogeneities in the photon distribution is smoothed out by the processes of nonlinear dissipation and photon diffusion on mass scales. As initial inhomogenities of the energy density of the radiation field on scales less than the damping scale at recombination is not seen as an anisotropy in the microwave background but as a spectral distortion of the background. Signatures of pressure wave damping over certain redshift intervals are identified, and an upper bound is obtained for the index of the initial power spectrum of the mass distribution. 35 refs.

  18. Results from the Project 8 phase-1 cyclotron radiation emission spectroscopy detector

    NASA Astrophysics Data System (ADS)

    Ashtari Esfahani, A.; Böser, S.; Claessens, C.; de Viveiros, L.; Doe, P. J.; Doeleman, S.; Fertl, M.; Finn, E. C.; Formaggio, J. A.; Guigue, M.; Heeger, K. M.; Jones, A. M.; Kazkaz, K.; LaRoque, B. H.; Machado, E.; Monreal, B.; Nikkel, J. A.; Oblath, N. S.; Robertson, R. G. H.; Rosenberg, L. J.; Rybka, G.; Saldaña, L.; Slocum, P. L.; Tedeschi, J. R.; Thümmler, T.; Vandevender, B. A.; Wachtendonk, M.; Weintroub, J.; Young, A.; Zayas, E.

    2017-09-01

    The Project 8 collaboration seeks to measure the absolute neutrino mass scale by means of precision spectroscopy of the beta decay of tritium. Our technique, cyclotron radiation emission spectroscopy, measures the frequency of the radiation emitted by electrons produced by decays in an ambient magnetic field. Because the cyclotron frequency is inversely proportional to the electron’s Lorentz factor, this is also a measurement of the electron’s energy. In order to demonstrate the viability of this technique, we have assembled and successfully operated a prototype system, which uses a rectangular waveguide to collect the cyclotron radiation from internal conversion electrons emitted from a gaseous 83m Kr source. Here we present the main design aspects of the first phase prototype, which was operated during parts of 2014 and 2015. We will also discuss the procedures used to analyze these data, along with the features which have been observed and the performance achieved to date.

  19. An Enhanced Box-Wing Solar Radiation pressure model for BDS and initial results

    NASA Astrophysics Data System (ADS)

    Zhao, Qunhe; Wang, Xiaoya; Hu, Xiaogong; Guo, Rui; Shang, Lin; Tang, Chengpan; Shao, Fan

    2016-04-01

    Solar radiation pressure forces are the largest non-gravitational perturbations acting on GNSS satellites, which is difficult to be accurately modeled due to the complicated and changing satellite attitude and unknown surface material characteristics. By the end of 2015, there are more than 50 stations of the Multi-GNSS Experiment(MGEX) set-up by the IGS. The simple box-plate model relies on coarse assumptions about the dimensions and optical properties of the satellite due to lack of more detailed information. So, a physical model based on BOX-WING model is developed, which is more sophisticated and more detailed physical structure has been taken into account, then calculating pressure forces according to the geometric relations between light rays and surfaces. All the MGEX stations and IGS core stations had been processed for precise orbit determination tests with GPS and BDS observations. Calculation range covers all the two kinds of Eclipsing and non-eclipsing periods in 2015, and we adopted the un-differential observation mode and more accurate values of satellite phase centers. At first, we tried nine parameters model, and then eliminated the parameters with strong correlation between them, came into being five parameters of the model. Five parameters were estimated, such as solar scale, y-bias, three material coefficients of solar panel, x-axis and z-axis panels. Initial results showed that, in the period of yaw-steering mode, use of Enhanced ADBOXW model results in small improvement for IGSO and MEO satellites, and the Root-Mean-Square(RMS) error value of one-day arc orbit decreased by about 10%~30% except for C08 and C14. The new model mainly improved the along track acceleration, up to 30% while in the radial track was not obvious. The Satellite Laser Ranging(SLR) validation showed, however, that this model had higher prediction accuracy in the period of orbit-normal mode, compared to GFZ multi-GNSS orbit products, as well with relative post

  20. Results of a 5-Week Schedule of Modern Total Skin Electron Beam Radiation Therapy

    SciTech Connect

    Morris, Stephen Lloyd; McGovern, Mark; Bayne, Sally; Wain, Mary; Child, Fiona; Whittaker, Sean

    2013-08-01

    Purpose: To report the outcomes of a 5-week schedule of total skin electron beam radiation therapy (TSEB) for mycosis fungoides (MF). Methods: Over 5 years, 41 patients with confirmed MF were treated with a modern TSEB technique delivering 30 Gy in 20 fractions over 5 weeks to the whole skin surface. Data were collected prospectively and entered into the skin tumor unit research database. Skin modified skin weighted assessment tool score data were collected to determine response, duration of response, survival, and toxicity. The outcomes were analyzed according to the patient's stage before TSEB, prognostic factors, and adjuvant treatments. Results: Seventeen patients were stage 1B, 19 were stage IIB, 3 were stage III, and 2 were stage IV. The overall response rate was 95%, with a complete response rate of 51%. Seventy-six percent of patients had relapsed at median follow-up of 18 months. The median time to relapse was 12 months, to systemic therapy was 15 months, and to modified skin weighted assessment tool progression above baseline was 44 months. The complete response rate was 59% in stage IB and 47% in stage IIB patients. The median time to skin relapse was longer in stage IB compared with stage IIB, 18 months versus 9 months. The median time to systemic therapy was longer in stage IB compared with stage IIB, >56 months versus 8 months. The median overall survival was 35 months: >56 months for stage IB, 25 months for stage IIB, 46 months for stage III, and 23.5 months for stage IV. Fifteen patients received adjuvant psoralen + ultraviolet A treatment with no difference seen in the time to relapse. Conclusions: This 5-week schedule of TSEB for MF has a high response rate with comparable duration of response to other regimens. Future studies are needed to find adjuvant and combination treatments to improve the duration of response.

  1. Results of nimotuzumab and vinorelbine, radiation and re-irradiation for diffuse pontine glioma in childhood.

    PubMed

    Massimino, Maura; Biassoni, Veronica; Miceli, Rosalba; Schiavello, Elisabetta; Warmuth-Metz, Monika; Modena, Piergiorgio; Casanova, Michela; Pecori, Emilia; Giangaspero, Felice; Antonelli, Manila; Buttarelli, Francesca Romana; Potepan, Paolo; Pollo, Bianca; Nunziata, Raffaele; Spreafico, Filippo; Podda, Marta; Anichini, Andrea; Clerici, Carlo Alfredo; Sardi, Iacopo; De Cecco, Loris; Bode, Udo; Bach, Ferdinand; Gandola, Lorenza

    2014-06-01

    Radiotherapy is the only treatment definitely indicated for diffuse pontine gliomas (DIPG). Findings on the role of EGFR signaling in the onset of childhood DIPG prompted the use of nimotuzumab, an anti-EGFR monoclonal antibody. Assuming a potential synergy with both radiotherapy and vinorelbine, a pilot phase 2 protocol was launched that combined nimotuzumab with concomitant radiation and vinorelbine. An amendment in July 2011 introduced re-irradiation at relapse. The primary endpoint for first-line treatment was objective response rate (CR + PR + SD) according to the RECIST. This report concerns the outcome of this strategy as a whole. Vinorelbine 20 mg/m(2) was administered weekly, with nimotuzumab 150 mg/m(2) in the first 12 weeks of treatment; radiotherapy was delivered from weeks 3 to 9, for a total dose of 54 Gy. Vinorelbine 25 mg/m(2) and nimotuzumab were given every other week thereafter until the tumor progressed or for up to 2 years. Re-irradiation consisted of 19.8 Gy, fractionated over 11 days. Baseline and latest MRIs were assessed blindly by an outside neuroradiologist. Twenty five children (mean age 7.4 years) were enrolled as of August 2009 (median follow-up 29 months). A response was observed in 24/25 patients (96 %). The nimotuzumab/vinorelbine combination was very well tolerated, with no acute side-effects. Eleven of 16 locally-relapsing patients were re-irradiated. One-year PFS and OS rates were 30 ± 10 % and 76 ± 9 %, respectively; 2-year OS was 27 ± 9 %; the median PFS and OS were 8.5 and 15 months, respectively. This strategy generated interesting results and warrants further investigation.

  2. Variation in CT pediatric head examination radiation dose: results from a national survey.

    PubMed

    Kanal, Kalpana M; Graves, Janessa M; Vavilala, Monica S; Applegate, Kimberly E; Jarvik, Jeffrey G; Rivara, Frederick P

    2015-03-01

    OBJECTIVE. The purpose of this article is to examine the variation in radiation dose, CT dose index volume (CTDIvol), and dose-length product (DLP) for pediatric head CT examinations as a function of hospital characteristics across the United States. MATERIALS AND METHODS. A survey inquiring about hospital information, CT scanners, pediatric head examination protocol, CTDIvol, and DLP was mailed to a representative sample of U.S. hospitals. Follow-up mailings were sent to nonrespondents. Descriptive characteristics of respondents and nonrespondents were compared using design-based Pearson chi-square tests. Dose estimates were compared across hospital characteristics using Bonferroni-adjusted Wald test. Hospital-level factors associated with dose estimates were evaluated using multiple linear regressions and modified Poisson regression models. RESULTS. Surveys were sent out to 751 hospitals; 292 responded to the survey, of which 253 were eligible (35.5% response rate, calculated as number of hospitals who completed surveys [n = 253] divided by sum of number who were eligible and initially consented [n = 712] plus estimated number who were eligible among those who refused [n = 1]). Most respondents reported using MDCT scanners (99.2%) and having a dedicated pediatric head CT protocol (93%). Estimated mean reported CTDIvol values were 27.3 mGy (95% CI, 24.4-30.1 mGy), and DLP values were 390.9 mGy × cm (95% CI, 346.6-435.1 mGy × cm). These values did not vary significantly by region, trauma level, teaching status, CT accreditation, number of CT scanners, or report of a dedicated pediatric CT protocol. However, estimated CTDIvol reported by children's hospitals was 19% lower than that reported by general hospitals (p < 0.01). CONCLUSION. Most hospitals (82%) report doses that meet American College of Radiology accreditation levels. However, [corrected] the mean CTDI(vol) at children's hospitals was approximately 7 mGy (21%, adjusted for covariates), lower than that

  3. First results of measurements of extreme ultraviolet radiation onboard a geostationary satellite "ELECTRO-L"

    NASA Astrophysics Data System (ADS)

    Nusinov, Anatoliy; Kazachevskaya, Tamara; Gonjukh, David

    Measurements of the intensity of EUV emission in the hydrogen Lyman-alpha line were conducted by a broadband photometer VUSS-E onboard geostationary Hydrometeorological satellite "Electro" since March 2011. The solar hydrogen Lyman-alpha line (lambda = 121.6 nm) was monitored. The photomultiplier with LiF window used as a detector insensitive to visible light. Long-wavelength limit of the spectral band sensitivity of the instrument is about 200 nm, so the signal of the device is defined as the flux of solar radiation in the region of 123-200 nm. Its exclusion was carried out by calculation. Since the satellite "Electro" designed for remote sensing of the Earth, its line of sight focused on Earth. Alignment of instrument in the Sun direction was achieved by installing it on the solar panel, periodically moved in the solar direction. Correction of instrument readings, reduced due to the deviation of its axis from the Sun direction, carried out by calculation. Measurements were carried out every second. The first results of the measurements are presented. The difference in absolute calibration Electro-L/VUSS-E is within 5% of corresponding values for measurements TIMED satellite in those days, that is in agreement with laboratory calibrations. It is useful to measure the temperature of the instrument, as its variation on a small interval of time makes change the value of the output signal about 1-2 %. During first year of operation, the sensitivity of the apparatus remained within ± 2% of measured value, significant degradation of sensitivity was not observed. Over time of observation there have been several large flares of X class. The increase of the signal in the ultraviolet range does not exceed a few percent during these flares.

  4. Radiation control coatings installed on rough-surfaced built-up roofs -- Initial results

    SciTech Connect

    Petrie, T.W.; Childs, P.W.; Christian, J.E.

    1998-01-01

    The authors have tracked the solar reflectance and thermal performance of small samples of various radiation control coatings on smooth surfaces for several years on a roof test facility in East Tennessee. The focus is on white coatings because of their potential to weather, causing the solar reflectance to decrease as the coatings age. Support of the federal New Technology Demonstration Program allowed them to extend the study to more samples on smooth surfaces and entire rough-surfaced roofs at a federal facility in the Panhandle of Florida. Two rough-surfaced, moderately well-insulated, low solar reflectance built-up roofs (BURs) were spray-coated with a latex-based product with ceramic beads added to improve solar reflectance. In the first three months after installation, the fresh BUR coatings showed a significant decrease in both the outside-surface temperature and the heat flux through the roof insulation. Average sunlit values were generated to exclude nighttime data, data on cloudy days, and data when the uncoated patch on one roof was more strongly shaded in mid-afternoon on sunny days. The average power demand during occupied periods for the first month with the coating for the building with the thermally massive roof deck was 13% less than during the previous month without the coating. For the other buildings with a lightweight roof deck but high internal loads, there were no clear average power savings due to the coating. The authors are continuing to monitor electricity use in these all-electric buildings to calibrate a model for the peak power and annual energy use of the buildings. Modeling results to be given at the end of the two year project will address the effect of roof R-value, geographic location, and solar reflectance, including the effect of weathering, on the performance of coated roofs. The calibrated models should allow one to segregate site-specific effects such as shading and large thermal mass.

  5. Summary of radiation dosimetry results on U.S. and Soviet manned spacecraft.

    PubMed

    Benton, E V

    1986-01-01

    Measurements of the radiation environment aboard U.S. and Soviet manned spacecraft are reviewed and summarized. Data obtained mostly from passive and some active radiation detectors now exist for the case of low Earth-orbit missions. Major uncertainties still exist for space exposure in high altitude, high inclination, geostationary orbits, in connection with solar effects and that of shielding. Data from active detectors flown in Spacelabs 1 and 2 suggest that a variety of phenomena must be understood before the effects of long-term exposure at the space-station type of orbit and shielding can be properly assessed.

  6. Radiation results in IL-8 mediated intercellular signaling that increases adhesion between monocytic cells and aortic endothelium

    NASA Astrophysics Data System (ADS)

    Kucik, Dennis; Babitz, Stephen; Dunaway, Chad; Steele, Chad

    Epidemiological evidence has established terrestrial radiation exposure as a risk factor for cardiovascular disease. For example, a major side effect of therapeutic radiation, especially for breast and head-and-neck cancers, is atherosclerosis, which can result in stroke years after treatment. Similarly, atomic bomb survivors were significantly more likely to die of cardiovascular disease than their countrymen. Even radiation technologists, prior to 1950 (when regulations governing shielding and occupational exposure were less rigorous) had an increased risk of clinically significant atherosclerosis. We have recently shown that 600 MeV (56) Fe similarly exacerbates plaque formation in the apoE mouse atherosclerosis model at doses 4-7 fold lower than required for x-rays to produce a similar pro-atherogenic effect. This raises concern that exposure to cosmic radiation might pose a similar risk for astronauts. Because so little is known about the mechanism of pro-atherogenic radiation effects, however, the current strategy to minimize risk from terrestrial radiation sources is to limit exposure. For astronauts on deep space missions, exposure to a significant amount of radiation will be unavoidable. Therefore, an understanding of the mechanism of radiation-induced atherosclerosis will be essential in order to develop countermeasures. Radiation can cause increased adhesiveness of vascular endothelium, leading to inappropriate accumulation of monocytes and other white blood cells, which can initiate a self-perpetuating inflammatory response. This vascular inflammation is an early event in atherosclerosis that can eventually lead to clinically significant cardiovascular events such as myocardial infarction and stroke. We showed earlier that x-rays, (56) Fe, and (28) Si all accelerate development of atherosclerosis in the apoE -/- mouse model. We also demonstrated that both x-rays and heavy ions increase adhesion of monocytic cells to vascular human aortic endothelial

  7. Consecutive results of blood cell count and retrospective biodosimetry: useful tools of health protection regulation for radiation workers

    PubMed Central

    Jang, Seongjae; Lee, Jin Kyung; Cho, Minsu; Yang, Su San; Kim, Seung Hyun; Kim, Wan Tae

    2016-01-01

    Background Industrial radiography is known to be one of the most vulnerable lines of work among the range of different radiation work. According to the relevant law in Korea, every worker registered in this work should check their blood cell counts every year in addition to their thermoluminescent dosimeter (TLD) doses. Since the law was enacted, however, few follow-up studies have been carried out based on the obtained results. Objectives To ascertain the clinical usefulness of complete blood cell count (CBC) results and suggest a proper protocol of health protection for radiation workers. Methods After reviewing all the consecutive results of CBC and TLD doses from radiation workers registered nationwide, we selected two groups of high-risk radiation workers, CBC-high risk (CBC-HR) and TLD-high risk (TLD-HR) groups. A control group of unexposed healthy adults was also included. We compared the absorbed doses calculated by cytogenetic biodosimetry among those three groups, and examined possible confounding factors for each group. Results Both groups of high-risk radiation workers, CBC-HR and TLD-HR, showed higher chromosome aberrations than the control group. In the control group, previous medical history of a CT scan increased the frequency of chromosome aberrations. In contrast, the frequency of chromosome aberrations in the high-risk radiation workers was affected not by the previous CT history but only by the duration of their work. Conclusions We ascertain that reviewing consecutive results of blood cell counts and cytogenetic biodosimetry are useful complementary tools to TLD doses for health protection regulation. Several confounding factors including work duration and previous medical history need to be considered for the interpretation of biodosimetry results. PMID:27466611

  8. Global and Regional Climate Responses Solar Radiation Management: Results from a climateprediction.net Geoengineering Experiment

    NASA Astrophysics Data System (ADS)

    Ricke, Katharine; Allen, Myles; Ingram, William; Keith, David; Granger Morgan, M.

    2010-05-01

    To date modeling studies suggest that, while significant hydrological anomalies could result from the artificial addition of reflecting aerosols in the stratosphere for the purpose of solar radiation management (SRM), even at the regional level such a geoengineered world would bear a much closer resemblance to a low CO2 world, than to an unmodified high CO2 world. These previous modeling studies have generally compared one or two SRM forcing scenarios to various business-as-usual controls. However, such approaches cannot provide much information about regional sensitivities to the levels of SRM that might realistically result. Should engaging in SRM every be seriously contemplated, such regional analysis of a range of realistic scenarios will be an essential input to any process of geopolitical decision-making. Here we present the results from a large-ensemble experiment that used the HadCM3L GCM, implemented through climateprediction.net. The analysis examines 135 globally-uniform stratospheric optical depth modification scenarios designed to stabilize global temperatures under SRES A1B. Scenarios were tested using ten-member subensembles which made small perturbations to initial conditions. All simulations use identical standard settings of model physics parameters and are initiated from historically-forced runs from 1920-2005. A total of 7,331 simulations of the years 2000-2080 were performed for this experiment using computing resources donated by the general public. Our analysis of regional temperature and precipitation anomalies, normalized to account for variability, shows that SRM compensations for anthropogenic greenhouse gas forcing do generally return regional climates closer to their baseline climate states than the no-geoengineering, business-as-usual scenarios. However, we find that the magnitudes and sensitivities of regional responses to this type of activity, as modeled in HadCM3L, are highly variable. As the amount of SRM increases to compensate

  9. A lithography aware design optimization using foundry-certified models and hotspot detection

    NASA Astrophysics Data System (ADS)

    Karklin, L.; Arkhipov, A.; Blakely, D.; Dingenen, M.; Mehrotra, A.; Watson, B.; Zelnik, C.; Cote, M.; Hurat, P.

    2007-10-01

    An automated litho-aware design migration solution has been implemented to enable designers to port existing IP layouts (custom, library, and block) to nanometer technologies while optimizing layout printability and silicon yield. With rapidly shrinking technology nodes, the industry consolidation toward fabless or fab-lite manufacturing, demand for second-sourcing and dramatic increase in cost of IP development, the automation of "vertical" (between nodes) and 'horizontal" (between chip manufacturers) migration becomes a very important task. The challenge comes from the fact that even within the same technology node design and process-induced rules deviate substantially among different IDMs and foundries, which leads to costly, error-prone and time consuming design modifications. At the same time, fast and reliable adjustments to design and ability to switch between processes and chip manufacturers could represent significant improvement to TTM, and respectively improving ROI. Using conservative rules (or restricted design rules) is not always a viable option because of the area, performance and yield penalties. The difficulty of migration is augmented by the fact that design rules are not sufficient to guaranty good printability, maximum process window and high yield. Model-based detection of lithography-induced systematic yield-limiting defects (a.k.a. hotspots) is becoming a vital part of the design-for-manufacturing flow for advanced technology nodes at 65nm and below. Driven by customer demand, a collaborative effort between EDA vendors provides a complete design-for-manufacturing migration solution that allows sub-65 nanometer designers to comprehensively address the impact of manufacturing variations on design yield and performance during layout migration. First, the physical hard IP is migrated from its existing 90nm process to a more advanced 65 and 45 nm processes, resulting in an area-optimized DRC-clean 65nm design retaining the original hierarchy to

  10. Unique properties of multiple tandem copies of the M26 recombination hotspot in mitosis and meiosis in Schizosaccharomyces pombe.

    PubMed

    Steiner, Walter W; Recor, Chelsea L; Zakrzewski, Bethany M

    2016-11-15

    The M26 hotspot of the fission yeast Schizosaccharomyces pombe is one of the best-characterized eukaryotic hotspots of recombination. The hotspot requires a seven bp sequence, ATGACGT, that serves as a binding site for the Atf1-Pcr1 transcription factor, which is also required for activity. The M26 hotspot is active in meiosis but not mitosis and is active in some but not all chromosomal contexts and not on a plasmid. A longer palindromic version of M26, ATGACGTCAT, shows significantly greater activity than the seven bp sequence. Here, we tested whether the properties of the seven bp sequence were also true of the longer sequence by placing one, two, or three copies of the sequence into the ade6 gene, where M26 was originally discovered. These constructs were tested for activity when located on a plasmid or on a chromosome in mitosis and meiosis. We found that two copies of the 10bp M26 motif on a chromosome were significantly more active for meiotic recombination than one, but no further increase was observed with three copies. However, three copies of M26 on a chromosome created an Atf1-dependent mitotic recombination hotspot. When located on a plasmid, M26 also appears to behave as a mitotic recombination hotspot; however, this behavior most likely results from Atf1-dependent inter-allelic complementation between the plasmid and chromosomal ade6 alleles.

  11. Reduced patient anxiety as a result of radiation therapist-led psychosocial support: a systematic review.

    PubMed

    Elsner, Kelly; Naehrig, Diana; Halkett, Georgia K B; Dhillon, Haryana M

    2017-02-03

    Up to 49% of patients attending radiation therapy appointments may experience anxiety and distress. Anxiety is heightened during the first few visits to radiation oncology. Radiation therapists (RT) are the only health professionals in direct daily contact with patients during treatment, placing them in a unique position to explore patients' psychosocial needs. This review aims to synthesise literature regarding the effect of RT-led psychosocial support on patient anxiety. In May 2015, we searched the following electronic databases: Medline, PsycINFO, Embase, CINAHL, PubMed and Cochrane library. Radiation therapy-specific journals were hand-searched, and reference lists of identified studies searched. This review complies with Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. The search identified 263 articles, of which 251 were excluded based on non-English language, duplicate article or relevance. A total of 12 articles involving 1363 patients were included and categorised into three broad themes: 'Patient Perspectives' 3 articles, 'Patient Information and Education' 5 articles and 'Screening and Needs Assessment' 4 articles. Two publications referred to the same sample and data. Quality ratings were mixed, with one study rated 'high' quality, seven 'moderate' and four 'low'. Methodological weaknesses were identified in relation to workflow, sample size and responder bias. RTs have a role in psychosocial support through increased communication and information sharing, which can benefit both patients and staff. RT-led practices such as relationship building, patient education sessions and screening and needs assessments are feasible and can reduce anxiety.

  12. Students' Conceptions about "Radiation": Results from an Explorative Interview Study of 9th Grade Students

    ERIC Educational Resources Information Center

    Neumann, Susanne; Hopf, Martin

    2012-01-01

    One basis of good teaching is to know about your students' preconceptions. Studies about typical ideas that students bring to the science classroom have been and continue to be a major field in science education research. This study aims to explore associations and ideas that students have regarding "radiation", a term widely used in…

  13. Ionizing radiation test results for an automotive microcontroller on board the Schiaparelli Mars lander

    NASA Astrophysics Data System (ADS)

    Tapani Nikkanen, Timo; Hieta, Maria; Schmidt, Walter; Genzer, Maria; Haukka, Harri; Harri, Ari-Matti

    2016-04-01

    The Finnish Meteorological Institute (FMI) has delivered a pressure and a humidity instrument for the ESA ExoMars 2016 Schiaparelli lander mission. Schiaparelli is scheduled to launch towards Mars with the Trace Gas Orbiter on 14th of March 2016. The DREAMS-P (pressure) and DREAMS-H (Humidity) instruments are operated utilizing a novel FMI instrument controller design based on a commercial automotive microcontroller (MCU). A custom qualification program was implemented to qualify the MCU for the relevant launch, cruise and surface operations environment of a Mars lander. Resilience to ionizing radiation is one of the most critical requirements for a digital component operated in space or at planetary bodies. Thus, the expected Total Ionizing Dose accumulated by the MCU was determined and a sample of these components was exposed to a Co-60 gamma radiation source. Part of the samples was powered during the radiation exposure to include the effect of electrical biasing. All of the samples were verified to withstand the expected total ionizing dose with margin. The irradiated test samples were then radiated until failure to determine their ultimate TID.

  14. Students' Conceptions About `Radiation': Results from an Explorative Interview Study of 9th Grade Students

    NASA Astrophysics Data System (ADS)

    Neumann, Susanne; Hopf, Martin

    2012-12-01

    One basis of good teaching is to know about your students' preconceptions. Studies about typical ideas that students bring to the science classroom have been and continue to be a major field in science education research. This study aims to explore associations and ideas that students have regarding `radiation', a term widely used in various fields and necessary to understand fundamental ideas in science. In an explorative study, the perceptions of 50 high school students were examined using semi-structured interviews. The students were 14-16 years old and were chosen from 7 different high schools in an urban area in Austria. Following an interview guideline, students were asked about their general associations with the term `radiation' as well as about their general understanding of different types of radiation. A qualitative analysis of these interviews following the method of Flick (2009) revealed that the students' associations were, to a great extent, very different from the scientific use of the term. Several conceptions that could inhibit students' learning processes could be identified. Consequences for the teaching of the topic `radiation' in science lessons, which are based on these preconceptions, are presented in the conclusion.

  15. Students' Conceptions about "Radiation": Results from an Explorative Interview Study of 9th Grade Students

    ERIC Educational Resources Information Center

    Neumann, Susanne; Hopf, Martin

    2012-01-01

    One basis of good teaching is to know about your students' preconceptions. Studies about typical ideas that students bring to the science classroom have been and continue to be a major field in science education research. This study aims to explore associations and ideas that students have regarding "radiation", a term widely used in…

  16. Higher Chest Wall Dose Results in Improved Locoregional Outcome in Patients Receiving Postmastectomy Radiation

    SciTech Connect

    Panoff, Joseph E.; Takita, Cristiane; Hurley, Judith; Reis, Isildinha M.; Zhao, Wei; Rodgers, Steven E.; Gunaseelan, Vijayalakshmi; Wright, Jean L.

    2012-03-01

    Purpose: Randomized trials demonstrating decreased locoregional recurrence (LRR) and improved overall survival (OS) in women receiving postmastectomy radiation therapy (PMRT) used up to 50 Gy to the chest wall (CW), but in practice, many centers boost the CW dose to {>=}60 Gy, despite lack of data supporting this approach. We evaluated the relationship between CW dose and clinical outcome. Methods and Materials: We retrospectively reviewed medical records of 582 consecutively treated patients who received PMRT between January 1999 and December 2009. We collected data on patient, disease, treatment characteristics, and outcomes of LRR, progression-free survival (PFS) and OS. Results: Median follow-up from the date of diagnosis was 44.7 months. The cumulative 5-year incidence of LRR as first site of failure was 6.2%. CW dose for 7% (43 patients) was {<=}50.4 Gy (range, 41.4-50.4 Gy) and 93% received >50.4 Gy (range, 52.4-74.4 Gy). A CW dose of >50.4 Gy vs. {<=}50.4 Gy was associated with lower incidence of LRR, a 60-month rate of 5.7% (95% confidence interval [CI], 3.7-8.2) vs. 12.7% (95% CI, 4.5-25.3; p = 0.054). Multivariate hazard ratio (HR) for LRR controlling for race, receptor status, and stage was 2.62 (95% CI, 1.02-7.13; p = 0.042). All LRR in the low-dose group occurred in patients receiving 50 to 50.4 Gy. Lower CW dose was associated with worse PFS (multivariate HR, 2.73; 95% CI, 1.64-4.56; p < 0.001) and OS (multivariate HR, 3.88; 95% CI, 2.16-6.99; p < 0.001). Conclusions: The addition of a CW boost above 50.4 Gy resulted in improved locoregional control and survival in this cohort patients treated with PMRT for stage II-III breast cancer. The addition of a CW boost to standard-dose PMRT is likely to benefit selected high-risk patients. The optimal technique, target volume, and patient selection criteria are unknown. The use of a CW boost should be studied prospectively, as has been done in the setting of breast conservation.

  17. Radiative Transfer Modeling of AVHRR Brightness Temperatures for Improved Sea Surface Temperature Retrievals: Initial Results

    NASA Astrophysics Data System (ADS)

    Ignatov, A.; Dash, P.

    2007-05-01

    Operational Sea Surface Temperature (SST) products at NOAA/NESDIS have been derived from the Advanced Very High Resolution Radiometers (AVHRR) onboard NOAA satellites since the early 1980s. The two major SST algorithms, the multi-channel and non-linear SST (MC/NLSST), were initially introduced for the AVHRR in the mid- 1980s and mid-1990s, respectively. Both algorithms are based on solid physical principles but also include some empirical elements (such as for instance treatment of the view angle dependence in the SST equations and tuning their coefficients against in-situ SST), to account for approximations and assumptions in their derivation. The simple MC/NLSST formulations proved to be accurate and robust, and are still in use with the newer sensors, such as the Moderate Resolution Imaging Spectro-Radiometer (MODIS). They are also considered for the future sensors such as the Visible Infrared Imager and Radiometer Suite (VIIRS) onboard NPOESS, and the Advanced Baseline Imager (ABI) onboard GOES-R. Despite the apparent success and good accuracies, improved SST formulations should be explored based on improved and accurate Radiative Transfer Models (RTM). In order to be useful for inverse problem simulation (i.e., SST retrieval), the RTM should be able to adequately reproduce the top-of-the-atmosphere brightness temperatures. In this study, we use MODTRAN 4.2 model, coupled with two surface reflection models (black body and Fresnel), to simulate TOA brightness temperatures in the three thermal infrared AVHRR bands. Atmospheric profiles and SST come from the National Centers for Environmental Prediction (NCEP) Global Data Analysis System (GDAS) data as input, assuming aerosol- and cloud-free conditions. The simulation results are then convoluted with the respective relative spectral response functions of the individual sensors, and compared with collocated TOA brightness temperatures measured from NOAA-16, -17, and -18 satellites during nighttime. Initial results

  18. Characteristics of suicide hotspots on the Belgian railway network.

    PubMed

    Debbaut, Kevin; Krysinska, Karolina; Andriessen, Karl

    2014-01-01

    In 2004, railway suicide accounted for 5.3% of all suicides in Belgium. In 2008, Infrabel (Manager of the Belgian Railway Infrastructure) introduced a railway suicide prevention programme, including identification of suicide hotspots, i.e., areas of the railway network with an elevated incidence of suicide. The study presents an analysis of 43 suicide hotspots based on Infrabel data collected during field visits and semi-structured interviews conducted in mental health facilities in the vicinity of the hotspots. Three major characteristics of the hotspots were accessibility, anonymity, and vicinity of a mental health institution. The interviews identified several risk and protective factors for railway suicide, including the training of staff, introduction of a suicide prevention policy, and the role of the media. In conclusion, a comprehensive railway suicide prevention programme should continuously safeguard and monitor hotspots, and should be embedded in a comprehensive suicide prevention programme in the community.

  19. Spontaneous Mutation at a 5-Methylcytosine Hotspot Is Prevented by Very Short Patch (Vsp) Mismatch Repair

    PubMed Central

    Lieb, M.

    1991-01-01

    In many strains of Escherichia coli, the product of gene dcm methylates the internal cytosines in the sequence 5'CC(A or T)GG. Spontaneous deamination of 5-methylcytosine produces thymine which, if not corrected, can result in a transition mutation. 5-Methylcytosines in the lacI gene are hotspots for spontaneous C to T mutations. dcm is linked to vsr, a gene required for very short patch (VSP) repair. VSP repair corrects T.G mispairs in the following contexts: (GGTCC)(CTAGG), (GGACC)(CTTGG), (GTCC)(TAGG) and (GGTC)(CTAG). I have investigated the relationships between cytosine methylation, mutation, and VSP repair. Spontaneous mutations in the repressor (cI) gene of lambda prophage were isolated in wild-type and mutant lysogens. A hotspot for spontaneous mutation that corresponds with a 5-methylcytosine was observed in wild-type lysogens but was not present in bacteria lacking both methylase and VSP repair activity. Introduction of a plasmid containing dcm(+) and vsr(+) restored the mutation hotspot. If the added plasmid carried only dcm(+), the frequency of spontaneous mutations at the 5-methylcytosine was over 10-fold higher than in Dcm(+)Vsr(+) lysogens. The addition of vsr on a plasmid to a wild-type lysogen resulted in a 4-fold reduction in mutation at the hotspot. These findings support the previously untested hypothesis that VSP repair prevents mutations resulting from deamination of 5-methylcytosine. PMID:1829427

  20. Particle-In-Cell (PIC) code simulation results and comparison with theory scaling laws for photoelectron-generated radiation

    SciTech Connect

    Dipp, T.M. |

    1993-12-01

    The generation of radiation via photoelectrons induced off of a conducting surface was explored using Particle-In-Cell (PIC) code computer simulations. Using the MAGIC PIC code, the simulations were performed in one dimension to handle the diverse scale lengths of the particles and fields in the problem. The simulations involved monoenergetic, nonrelativistic photoelectrons emitted normal to the illuminated conducting surface. A sinusoidal, 100% modulated, 6.3263 ns pulse train, as well as unmodulated emission, were used to explore the behavior of the particles, fields, and generated radiation. A special postprocessor was written to convert the PIC code simulated electron sheath into far-field radiation parameters by means of rigorous retarded time calculations. The results of the small-spot PIC simulations were used to generate various graphs showing resonance and nonresonance radiation quantities such as radiated lobe patterns, frequency, and power. A database of PIC simulation results was created and, using a nonlinear curve-fitting program, compared with theoretical scaling laws. Overall, the small-spot behavior predicted by the theoretical scaling laws was generally observed in the PIC simulation data, providing confidence in both the theoretical scaling laws and the PIC simulations.

  1. Modelling Regional Hotspots of Water Pollution Induced by Salinization

    NASA Astrophysics Data System (ADS)

    Malsy, M.; Floerke, M.

    2014-12-01

    Insufficient water quality is one of the main global topics causing risk to human health, biodiversity, and food security. At this, salinization of water and land resources is widely spread especially in arid to semi-arid climates, where salinization, often induced by irrigation agriculture, is a fundamental aspect of land degradation. High salinity is crucial to water use for drinking, irrigation, and industrial purposes, and therefore poses a risk to human health and ecosystem status. However, salinization is also an economic problem, in particular in those regions where agriculture makes a significant contribution to the economy and/or where agriculture is mainly based on irrigation. Agricultural production is exposed to high salinity of irrigation water resulting in lower yields. Hence, not only the quantity of irrigation water is of importance for growing cops but also its quality, which may further reduce the available resources. Thereby a major concern for food production and security persists, as irrigated agriculture accounts for over 30% of the total agricultural production. In this study, the large scale water quality model WorldQual was applied to simulate recent total dissolved solids (TDS) loadings and in-stream concentrations from point and diffuse sources to get an insight on potential environmental impacts as well as risks to food security. Regional focus in this study is on developing countries, as these are most threatened by water pollution. Furthermore, insufficient water quality for irrigation and therefore restrictions in irrigation water use were examined, indicating limitations to crop production. For this purpose, model simulations were conducted for the year 2010 to show the recent status of surface water quality and to identify hotspots and main causes of pollution. Our results show that salinity hotspots mainly occur in peak irrigation regions as irrigated agriculture is by far the dominant sector contributing to water abstractions as

  2. Features and Initial Results of the DIII-D Advanced Tokamak Radiative Divertor

    SciTech Connect

    R.C. O'Neill; A.S. Bozek; M.E. Friend; C.B. Baxi; E.E. Reis; M.A. Mahdavi; D.G. Nilson; S.L. Allen; W.P. West

    1999-11-01

    The Radiative Divertor Program of DIII-D is in its final phase with the installation of the cryopump and baffle structure (Phase 1B Divertor) in the upper inner radius of the DIII-D vacuum vessel at the end of this calendar year. This divertor, in conjunction with the Advanced Divertor and the Phase 1A Divertor, located in the lower and upper outer radius of the DIII-D vacuum vessel respectively, provides pumping for density control of the plasma while minimizing the effects on the core confinement. Each divertor consists of a cryobelium cooling ring and a shielded protective structure. The cryo/helium-cooled pumps of all three diverters exhaust helium from the plasma. The protective shielded structure or baffle structure, in the case of the diverters located at the top of the vacuum vessel, provides baffling of neutral charged particles and minimize the flow of impurities back into the core of the plasma. The baffles, which consist of water-cooled panels that allow for the attachment of tiles of various sizes and shapes, house gas puff systems. The intent of the puffing systems is to inject gas in and around the divertor to minimize the heat flux on specific areas on the divertor and its components. The reduction of the heat flux on the divertor minimizes the impurities that are generated from excess heat on divertor components, specifically tiles. Experiments involving the gas puff systems and the divertor structures have shown the heat flux can be spread over a large area of the divertor, reducing the peak heat flux in specific areas. The three diverters also incorporate a variety of diagnostic tools such as halo current monitors, magnetic probes and thermocouples to monitor certain plasma characteristics as well as determine the effectiveness of the cryopumps and baffle configurations. The diverters were designed to optimize pumping performance and to withstand the electromagnetic loads from both halo currents and toroidal induced currents. Incorporated also

  3. Long-Term Results After Intraoperative Radiation Therapy for Gastric Cancer

    SciTech Connect

    Drognitz, Oliver Henne, Karl; Weissenberger, Christian; Bruggmoser, Gregor; Goebel, Heike; Hopt, Ulrich Theodor; Frommhold, Herrmann; Ruf, Guenther

    2008-03-01

    Purpose: We retrospectively analyzed the impact of intraoperative radiation therapy (IORT) on long-term survival in patients with resectable gastric cancer. Methods and Materials: From 1991 to 2001, a total of 84 patients with gastric neoplasms underwent gastectomy or subtotal resection with IORT (23 Gy, 6-15 MeV; IORT-positive [IORT{sup +}] group). Patients with a history of additional neoadjuvant chemotherapy, histologically confirmed R1 or R2 resection, or reoperation with curative intention after local recurrence were excluded from further analysis. The remaining 61 patients were retrospectively matched with 61 patients without IORT (IORT-negative [IORT{sup -}] group) for Union Internationale Contre le Cancer (UICC) stage, patient age, histologic grading, extent of surgery, and level of lymph node dissection. Subgroups included postoperative UICC Stages I (n = 31), II (n = 11), III (n = 14), and IV (n = 5). Results: Mean follow-up was 4.8 years in the IORT{sup +} group and 5.0 years in the IORT{sup -} group. The overall 5-year patient survival rate was 58% in the IORT{sup +} group vs. 59% in the IORT{sup -} group (p = 0.99). Subgroup analysis showed no impact of IORT on 5-year patient survival for those with UICC Stages I/II (76% vs. 80%; p = 0.87) and III/IV (21% vs. 14%, IORT{sup +} vs. IORT{sup -} group; p = 0.30). Perioperative mortality rates were 4.9% and 4.9% in the IORT{sup +} vs. IORT{sup -} group. Total surgical complications were more common in the IORT{sup +} than IORT{sup -} group (44.3% vs. 19.7%; p < 0.05). The locoregional tumor recurrence rate was 9.8% in the IORT{sup +} group. Conclusions: Use of IORT was associated with low locoregional tumor recurrence, but had no benefit on long-term survival while significantly increasing surgical morbidity in patients with curable gastric cancer.

  4. Hotspot detection in pancreatic neuroendocrine tumors: density approximation by α-shape maps

    NASA Astrophysics Data System (ADS)

    Niazi, M. K. K.; Hartman, Douglas J.; Pantanowitz, Liron; Gurcan, Metin N.

    2016-03-01

    The grading of neuroendocrine tumors of the digestive system is dependent on accurate and reproducible assessment of the proliferation with the tumor, either by counting mitotic figures or counting Ki-67 positive nuclei. At the moment, most pathologists manually identify the hotspots, a practice which is tedious and irreproducible. To better help pathologists, we present an automatic method to detect all potential hotspots in neuroendocrine tumors of the digestive system. The method starts by segmenting Ki-67 positive nuclei by entropy based thresholding, followed by detection of centroids for all Ki-67 positive nuclei. Based on geodesic distance, approximated by the nuclei centroids, we compute two maps: an amoeba map and a weighted amoeba map. These maps are later combined to generate the heat map, the segmentation of which results in the hotspots. The method was trained on three and tested on nine whole slide images of neuroendocrine tumors. When evaluated by two expert pathologists, the method reached an accuracy of 92.6%. The current method does not discriminate between tumor, stromal and inflammatory nuclei. The results show that α-shape maps may represent how hotspots are perceived.

  5. Are Hotspots Always Hotspots? The Relationship between Diversity, Resource and Ecosystem Functions in the Arctic

    PubMed Central

    Link, Heike; Piepenburg, Dieter; Archambault, Philippe

    2013-01-01

    The diversity-ecosystem function relationship is an important topic in ecology but has not received much attention in Arctic environments, and has rarely been tested for its stability in time. We studied the temporal variability of benthic ecosystem functioning at hotspots (sites with high benthic boundary fluxes) and coldspots (sites with lower fluxes) across two years in the Canadian Arctic. Benthic remineralisation function was measured as fluxes of oxygen, silicic acid, phosphate, nitrate and nitrite at the sediment-water interface. In addition we determined sediment pigment concentration and taxonomic and functional macrobenthic diversity. To separate temporal from spatial variability, we sampled the same nine sites from the Mackenzie Shelf to Baffin Bay during the same season (summer or fall) in 2008 and 2009. We observed that temporal variability of benthic remineralisation function at hotspots is higher than at coldspots and that taxonomic and functional macrobenthic diversity did not change significantly between years. Temporal variability of food availability (i.e., sediment surface pigment concentration) seemed higher at coldspot than at hotspot areas. Sediment chlorophyll a (Chl a) concentration, taxonomic richness, total abundance, water depth and abundance of the largest gallery-burrowing polychaete Lumbrineristetraura together explained 42% of the total variation in fluxes. Food supply proxies (i.e., sediment Chl a and depth) split hot- from coldspot stations and explained variation on the axis of temporal variability, and macrofaunal community parameters explained variation mostly along the axis separating eastern from western sites with hot- or coldspot regimes. We conclude that variability in benthic remineralisation function, food supply and diversity will react to climate change on different time scales, and that their interactive effects may hide the detection of progressive change, particularly at hotspots. Time-series of benthic functions and

  6. Methane Hotspots in the Los Angeles Megacity

    NASA Astrophysics Data System (ADS)

    Hopkins, F. M.; Randerson, J. T.; Bush, S.; Ehleringer, J. R.; Lai, C.; Kort, E. A.; Blake, D. R.

    2013-12-01

    Airborne observations show that Los Angeles (LA) is a large source of methane to the atmosphere, yet the sources of excess methane from the urban area are poorly constrained. We used a mobile laboratory, a Ford Transit van equipped with cavity ring down spectrometers (Picarro, Inc.), to measure greenhouse gases (CH4, CO2, and CO) mole fractions in LA. On-road surveys across the LA Basin were conducted seasonally to determine patterns of CH4 enrichment in space and over time, with a focus on quantifying methane leaks from known sources. We found fugitive leaks and elevated CH4 concentrations throughout the LA Basin. Some were associated with known sources, such as landfills, wastewater treatment, and oil and gas infrastructure, while others had an unknown origin. Urban CH4 enrichment varied over the course of the year, largely due to seasonal changes in meteorological conditions. Nevertheless, our mobile surveys revealed CH4 hotspots (>200 ppb elevated with respect to background levels) that persisted among seasons. High CH4 concentrations were most easily predicted by proximity to methane sources, particularly near the coast, while elevated CH4 levels were more evenly dispersed in inland areas. CH4 hotspots had a disproportionate impact on excess methane relative to the area they accounted for, typically providing more than a quarter of excess methane measured on a transect. These data improve estimates of the relative roles of specific leaks and emission sectors to LA's excess methane. Depending on the cost of reducing these CH4 leaks, a focus on CH4 emissions may prove an effective way to reduce LA's greenhouse gas emissions in the near term.

  7. Future hotspots of terrestrial mammal loss.

    PubMed

    Visconti, Piero; Pressey, Robert L; Giorgini, Daniele; Maiorano, Luigi; Bakkenes, Michel; Boitani, Luigi; Alkemade, Rob; Falcucci, Alessandra; Chiozza, Federica; Rondinini, Carlo

    2011-09-27

    Current levels of endangerment and historical trends of species and habitats are the main criteria used to direct conservation efforts globally. Estimates of future declines, which might indicate different priorities than past declines, have been limited by the lack of appropriate data and models. Given that much of conservation is about anticipating and responding to future threats, our inability to look forward at a global scale has been a major constraint on effective action. Here, we assess the geography and extent of projected future changes in suitable habitat for terrestrial mammals within their present ranges. We used a global earth-system model, IMAGE, coupled with fine-scale habitat suitability models and parametrized according to four global scenarios of human development. We identified the most affected countries by 2050 for each scenario, assuming that no additional conservation actions other than those described in the scenarios take place. We found that, with some exceptions, most of the countries with the largest predicted losses of suitable habitat for mammals are in Africa and the Americas. African and North American countries were also predicted to host the most species with large proportional global declines. Most of the countries we identified as future hotspots of terrestrial mammal loss have little or no overlap with the present global conservation priorities, thus confirming the need for forward-looking analyses in conservation priority setting. The expected growth in human populations and consumption in hotspots of future mammal loss mean that local conservation actions such as protected areas might not be sufficient to mitigate losses. Other policies, directed towards the root causes of biodiversity loss, are required, both in Africa and other parts of the world.

  8. Hotspots of land use change in Europe

    NASA Astrophysics Data System (ADS)

    Kuemmerle, Tobias; Levers, Christian; Erb, Karlheinz; Estel, Stephan; Jepsen, Martin R.; Müller, Daniel; Plutzar, Christoph; Stürck, Julia; Verkerk, Pieter J.; Verburg, Peter H.; Reenberg, Anette

    2016-06-01

    Assessing changes in the extent and management intensity of land use is crucial to understanding land-system dynamics and their environmental and social outcomes. Yet, changes in the spatial patterns of land management intensity, and thus how they might relate to changes in the extent of land uses, remains unclear for many world regions. We compiled and analyzed high-resolution, spatially-explicit land-use change indicators capturing changes in both the extent and management intensity of cropland, grazing land, forests, and urban areas for all of Europe for the period 1990-2006. Based on these indicators, we identified hotspots of change and explored the spatial concordance of area versus intensity changes. We found a clear East-West divide with regard to agriculture, with stronger cropland declines and lower management intensity in the East compared to the West. Yet, these patterns were not uniform and diverging patterns of intensification in areas highly suitable for farming, and disintensification and cropland contraction in more marginal areas emerged. Despite the moderate overall rates of change, many regions in Europe fell into at least one land-use change hotspot during 1990-2006, often related to a spatial reorganization of land use (i.e., co-occurring area decline and intensification or co-occurring area increase and disintensification). Our analyses highlighted the diverse spatial patterns and heterogeneity of land-use changes in Europe, and the importance of jointly considering changes in the extent and management intensity of land use, as well as feedbacks among land-use sectors. Given this spatial differentiation of land-use change, and thus its environmental impacts, spatially-explicit assessments of land-use dynamics are important for context-specific, regionalized land-use policy making.

  9. Future hotspots of terrestrial mammal loss

    PubMed Central

    Visconti, Piero; Pressey, Robert L.; Giorgini, Daniele; Maiorano, Luigi; Bakkenes, Michel; Boitani, Luigi; Alkemade, Rob; Falcucci, Alessandra; Chiozza, Federica; Rondinini, Carlo

    2011-01-01

    Current levels of endangerment and historical trends of species and habitats are the main criteria used to direct conservation efforts globally. Estimates of future declines, which might indicate different priorities than past declines, have been limited by the lack of appropriate data and models. Given that much of conservation is about anticipating and responding to future threats, our inability to look forward at a global scale has been a major constraint on effective action. Here, we assess the geography and extent of projected future changes in suitable habitat for terrestrial mammals within their present ranges. We used a global earth-system model, IMAGE, coupled with fine-scale habitat suitability models and parametrized according to four global scenarios of human development. We identified the most affected countries by 2050 for each scenario, assuming that no additional conservation actions other than those described in the scenarios take place. We found that, with some exceptions, most of the countries with the largest predicted losses of suitable habitat for mammals are in Africa and the Americas. African and North American countries were also predicted to host the most species with large proportional global declines. Most of the countries we identified as future hotspots of terrestrial mammal loss have little or no overlap with the present global conservation priorities, thus confirming the need for forward-looking analyses in conservation priority setting. The expected growth in human populations and consumption in hotspots of future mammal loss mean that local conservation actions such as protected areas might not be sufficient to mitigate losses. Other policies, directed towards the root causes of biodiversity loss, are required, both in Africa and other parts of the world. PMID:21844048

  10. Hot-spot mix in ignition-scale implosions on the NIF

    SciTech Connect

    Regan, S. P.; Epstein, R.; McCrory, R. L.; Meyerhofer, D. D.; Sangster, T. C.; Hammel, B. A.; Suter, L. J.; Ralph, J.; Scott, H.; Barrios, M. A.; Bradley, D. K.; Callahan, D. A.; Cerjan, C.; Collins, G. W.; Dixit, S. N.; Doeppner, T.; Edwards, M. J.; Farley, D. R.; Glenn, S.; Glenzer, S. H.; and others

    2012-05-15

    Ignition of an inertial confinement fusion (ICF) target depends on the formation of a central hot spot with sufficient temperature and areal density. Radiative and conductive losses from the hot spot can be enhanced by hydrodynamic instabilities. The concentric spherical layers of current National Ignition Facility (NIF) ignition targets consist of a plastic ablator surrounding a thin shell of cryogenic thermonuclear fuel (i.e., hydrogen isotopes), with fuel vapor filling the interior volume [S. W. Haan