Science.gov

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. Absorption of microwave radiation by the anesthetized rat: electromagnetic and thermal hotspots in body and tail

    SciTech Connect

    D'Andrea, J.A.; Emmerson, R.Y.; DeWitt, J.R.; Gandhi, O.P.

    1987-01-01

    Anatomic variability in the deposition of radiofrequency electromagnetic energy in mammals has been well documented. A recent study reported specific absorption rate (SAR) hotspots in the brain, rectum and tail of rat carcasses exposed to 360- and to 2450-MHz microwave radiation. Regions of intense energy absorption are generally thought to be of little consequence when predicting thermal effects of microwave irradiation because it is presumed that heat transfer via the circulatory system promptly redistributes localized heat to equilibrate tissue temperature within the body. Experiments on anesthetized, male Long-Evans rats (200-260 g) irradiated for 10 or 16 min with 2450, 700, or 360 MHz radiation at SARs of 2 W/kg, 6 W/kg, or 10 W/kg indicated that postirradiation localized temperatures in regions previously shown to exhibit high SARs were appreciably above temperatures at body sites with lower SARs. The postirradiation temperatures in the rectum and tail were significantly higher in rats irradiated at 360 MHz and higher in the tail at 2450 MHz than temperatures resulting from exposure to 700 MHz. This effect was found for whole-body-averaged SARs as low as 6 W/kg at 360 MHz and 10 W/kg at 2450 MHz. In contrast, brain temperatures in the anesthetized rats were not different from those measured in the rest of the body following microwave exposure.

  4. Absorption of microwave radiation by the anesthetized rat: Electromagnetic and thermal hotspots in body and tail

    SciTech Connect

    D'Andrea, J.A.; Emmerson, R.Y.; DeWitt, J.R.; Gandhi, O.P.

    1987-01-01

    Anatomic variability in the deposition of radiofrequency electromagnetic energy in mammals has been well documented. A recent study reported specific absorption rat (SAR) hotspots in the brain, rectum and tail of rat carcasses exposed to 360- and to 2,450-MHz microwave radiation. Regions of intense energy absorption are generally thought to be of little consequence when predicting thermal effects of microwave irradiation because it is presumed that heat transfer via the circulatory system promptly redistributes localized heat to equilibrate tissue temperature within the body. Experiments on anesthetized, male Long-Evans rats (200-260 g) irradiated for 10 or 16 min with 2,450, 700, or 360 MHz radiation at SARs of 2 W/kg, 6 W/kg, or 10 W/kg indicated that postirradiation localized temperatures in regions previously shown to exhibit high SARs were appreciably above temperatures at body sites with lower SARs. The postirradiation temperatures in the rectum and tail were significantly higher in rats irradiated at 360 MHz and higher in the tail at 2,450 MHz than temperatures resulting from exposure to 700 MHz. The effect was found for whole-body-averages SARs as low as 6 W/kg at 360 MHz and 10 W/g at 2,450 MHz.

  5. First Results from HOTSPOT: The Snake River Plain Scientific Drilling Project, Idaho, U.S.A.

    NASA Astrophysics Data System (ADS)

    Shervais, J. W.; Schmitt, D. R.; Nielson, D.; Evans, J. P.; Christiansen, E. H.; Morgan, L.; Shanks, W. C. Pat; Prokopenko, A. A.; Lachmar, T.; Liberty, L. M.; Blackwell, D. D.; Glen, J. M.; Champion, L. D.; Potter, K. E.; Kessler, J. A.

    2013-03-01

    HOTSPOT is an international collaborative effort to understand the volcanic history of the Snake River Plain (SRP). The SRP overlies a thermal anomaly, the Yellowstone-Snake River hotspot, that is thought to represent a deep-seated mantle plume under North America. The primary goal of this project is to document the volcanic and stratigraphic history of the SRP, which represents the surface expression of this hotspot, and to understand how it affected the evolution of continental crust and mantle. An additional goal is to evaluate the geothermal potential of southern Idaho. Project HOTSPOT has completed three drill holes. (1) The Kimama site is located along the central volcanic axis of the SRP; our goal here was to sample a long-term record of basaltic volcanism in the wake of the SRP hotspot. (2) The Kimberly site is located near the margin of the plain; our goal here was to sample a record of high-temperature rhyolite volcanism associated with the underlying plume. This site was chosen to form a nominally continuous record of volcanism when paired with the Kimama site. (3) The Mountain Home site is located in the western plain; our goal here was to sample the Pliocene-Pleistocene transition in lake sediments at this site and to sample older basalts that underlie the sediments. We report here on our initial results for each site, and on some of the geophysical logging studies carried out as part of this project. doi:10.2204/iodp.sd.15.06.2013

  6. 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

  7. ABSORPTION OF MICROWAVE RADIATION BY THE ANESTHETIZED RAT: ELECTROMAGNETIC AND THERMAL HOTSPOTS IN BODY AND TAIL

    EPA Science Inventory

    Anatomic variability in the deposition of radio frequency electromagnetic energy in mammals as been well documented. ecent study [D'Andrea et al. 1985] reported specific absorption rat (SAR) hotspots in the brain, rectum, and tail of rat carcasses exposed to 360- and to 2,450-MHz...

  8. 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

  9. 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

  10. 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.

  11. 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

  12. 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.

  13. 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.

  14. 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).

  15. 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

  16. 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.

  17. 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. PMID:26430059

  18. 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

  19. 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.

  20. HotSpot Health Physics Codes

    Energy Science and Technology Software Center (ESTSC)

    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. HotSpot Health Physics Codes

    Energy Science and Technology Software Center (ESTSC)

    2010-03-02

    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 incidents involving radioactive 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.

  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. 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.

  4. hotspot: software to support sperm-typing for investigating recombination hotspots

    PubMed Central

    Dutheil, Julien Y.; Klötzl, Fabian; Haubold, Bernhard

    2016-01-01

    Motivation: In many organisms, including humans, recombination clusters within recombination hotspots. The standard method for de novo detection of recombinants at hotspots is sperm typing. This relies on allele-specific PCR at single nucleotide polymorphisms. Designing allele-specific primers by hand is time-consuming. We have therefore written a package to support hotspot detection and analysis. Results: hotspot consists of four programs: asp looks up SNPs and designs allele-specific primers; aso constructs allele-specific oligos for mapping recombinants; xov implements a maximum-likelihood method for estimating the crossover rate; six, finally, simulates typing data. Availability and Implementation: hotspot is written in C. Sources are freely available under the GNU General Public License from http://github.com/evolbioinf/hotspot/ Contact: haubold@evolbio.mpg.de Supplementary information: Supplementary data are available at Bioinformatics online. PMID:27153632

  5. 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

  6. 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

  7. 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

  8. Preliminary results of radiation measurements on EURECA

    NASA Technical Reports Server (NTRS)

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

    1995-01-01

    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 does 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.

  9. Preliminary results of radiation measurements on EURECA

    NASA Technical Reports Server (NTRS)

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

    1995-01-01

    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 of 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 LET (greater than or equal to 6 keV/microns) 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 doses inside the flight canister varied from 18.8 plus or minus 0.6 cGy to 38.9 plus or minus 1.2 cGy. The TLD's oriented toward the least shielded direction averaged 53 percent 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 percent 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 in the LDEF experiments.

  10. Patterns of volcanism at oceanic intraplate hotspots

    NASA Astrophysics Data System (ADS)

    Kundargi, R.; Hall, P. S.

    2013-12-01

    One of the defining characteristics of plume-fed hotspots is the formation of a linear chain of age-progressive volcanoes [Wilson, 1963; Morgan, 1972; Courtillot et al, 2003]. However, in detail, the spatial distribution of volcanoes at oceanic hotspots is often complex and rarely takes the form of a simple linear array. Volcanoes at Hawaii, the archetype of plume-fed hotspots, have long been recognized to form two separate linear arrays, known as the Loa and Kea trends [Jackson, 1972]. Recent studies have suggested that volcanism at several additional hotspots, including the Samoa [Workman et al., 2004], Marquesas [Chauvel et al., 2009; Huang et al., 2011], and Society [Payne et al., 2012] hotspots, may also be loosely organized into sub-parallel trends. We have undertaken a systemic characterization of the spatial distribution of recent (3 Ma - present) magmatism, as reflected in bathymetry and topography, at a number of oceanic intraplate hotspots. We find that the average across-track (i.e., perpendicular to plate motion) bathymetric profile shows a distinct dual peak pattern at many hotspots. Characteristic spacing between peaks ranges from ~20 - 60 km and does not correlate with the age of the plate, as would be expected if the distribution of volcanism was being controlled by the elastic thickness of the plate [ten Brink, 1991]. Likewise, peak spacing does not appear to correlate with plate speed in the HS3 reference frame [Gripp and Gordon, 2002]. Spacing at individual hotspots does, however, correlate well with calculated plume buoyancy flux. This suggests that the time-averaged pattern, of dual-chain volcanism at the surface is reflects a bifurcated distribution of melting in the mantle rather than melt transport processes through the lithosphere. We propose that the dual-chain pattern of volcanism at hotspots results from the creation of a highly viscous plug of buoyant, dehydrated residuum that extends downwards from the base of the lithosphere

  11. 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).

  12. 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. PMID:19236450

  13. 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.

  14. 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

  15. Evaluating the Persistence of Shoreline Change Hotspots, Northern North Carolina

    NASA Astrophysics Data System (ADS)

    List, J. H.; Farris, A. S.; Sullivan, C.

    2002-12-01

    series and a three-year series of beach profiles surveyed by the U.S. Army Corps of Engineers in the 1970's. We find the mean shoreline position for each series through time-averaging, greatly reducing the variance due to short-term reversible hotspots and other sources of shoreline position variability. We then find shoreline change as the difference between the two series' mean shorelines, with shoreline change significance estimated with a standard t-test. Observations show that short-term reversible hotspots have both fixed and changing locations. Some hotspots repeatedly occur at fixed locations through multiple storms, while others occur only once, with the hotspot/coldspot pattern completely reorganized from one storm to the next. At a broader spatial scale (10's of km), there are zones where hotspots typically occur (with or without fixed locations for individual hotspots), while in other zones we have never observed hotspots during our three years of observations. Long-term hotspots also have both fixed and non-fixed characteristics, although the paucity of data relevant to this temporal scale make conclusions difficult. However, a preliminary comparison between our long-term change results (found as described above), and shoreline change results previously published by the State of North Carolina for a 50-year period ending in 1992, suggests that while the overall patterns of shoreline change (hotspots and coldspots) have remained the same, there is also some evidence for the along-coast migration of several of the most significant erosional hotspots.

  16. Breast tomography with synchrotron radiation: preliminary results

    NASA Astrophysics Data System (ADS)

    Pani, Silvia; Longo, Renata; Dreossi, Diego; Montanari, Francesco; Olivo, Alessandro; Arfelli, Fulvia; Bergamaschi, Anna; Poropat, Paolo; Rigon, Luigi; Zanconati, Fabrizio; Dalla Palma, Ludovico; Castelli, Edoardo

    2004-05-01

    A system for in vivo breast imaging with monochromatic x-rays has been designed and built at the synchrotron radiation facility Elettra in Trieste (Italy) and will be operational in 2004. The system design involves the possibility of performing both planar mammography and breast tomography. In the present work, the first results obtained with a test set-up for breast tomography are shown and discussed. Tomographic images of in vitro breasts were acquired using monochromatic x-ray beams in the energy range 20-28 keV and a linear array silicon pixel detector. Tomograms were reconstructed using standard filtered backprojection algorithms; the effect of different filters was evaluated. The attenuation coefficients of fibroglandular and adipose tissue were measured, and a quantitative comparison of images acquired at different energies was performed by calculating the differential signal-to-noise ratio of fibroglandular details in adipose tissue. All images required a dose comparable to the dose delivered in clinical, conventional mammography and showed a high resolution of the breast structures without the overlapping effects that limit the visibility of the structures in 2D mammography. A quantitative evaluation of the images proves that the image quality at a given dose increases in the considered energy range and for the considered breast sizes. This work is dedicated to the memory of Paolo Poropat, who died tragically on June 8th, 2002. He was a brilliant experimental scientist and gave relevant contributions to the fields of high energy physics and medical physics. He had a very rich and versatile personality, a brilliant character, a big vitality. We will never forget him, his love of life, the passion and the enthusiasm he put into everything he did.

  17. 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

  18. A coalescent model of recombination hotspots.

    PubMed Central

    Wiuf, Carsten; Posada, David

    2003-01-01

    Recent experimental findings suggest that the assumption of a homogeneous recombination rate along the human genome is too naive. These findings point to block-structured recombination rates; certain regions (called hotspots) are more prone than other regions to recombination. In this report a coalescent model incorporating hotspot or block-structured recombination is developed and investigated analytically as well as by simulation. Our main results can be summarized as follows: (1) The expected number of recombination events is much lower in a model with pure hotspot recombination than in a model with pure homogeneous recombination, (2) hotspots give rise to large variation in recombination rates along the genome as well as in the number of historical recombination events, and (3) the size of a (nonrecombining) block in the hotspot model is likely to be overestimated grossly when estimated from SNP data. The results are discussed with reference to the current debate about block-structured recombination and, in addition, the results are compared to genome-wide variation in recombination rates. A number of new analytical results about the model are derived. PMID:12750351

  19. 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

  20. 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.

  1. 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. PMID:26368021

  2. 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.

  3. Medulloblastoma: treatment results with radiation therapy

    SciTech Connect

    Lowery, G.S.; Ferree, C.R.; Raben, M.

    1981-09-01

    The treatment results in 18 patients with medulloblastoma were reviewed retrospectively. All patients were treated postoperatively with simultaneous craniospinal irradiation. Forty-four percent of the total group were alive without evidence of disease. Six of the 12 patients eligible for analysis at three years after completion of treatment had continuous disease-free survival. Six patients with intracranial recurrence received a second course of whole-brain irradiation, and two these are alive.

  4. Ultrasonic radiation from wedges of cubic profile: Experimental results.

    PubMed

    Anderson, Brian E; Remillieux, Marcel C; Le Bas, Pierre-Yves; Ulrich, T J; Pieczonka, Lukasz

    2015-12-01

    This paper presents experimental results demonstrating the increase in ultrasonic radiation obtained from a wedge of cubic profile relative to a plate of uniform thickness. The wedge of cubic profile provides high efficiency sound radiation matching layer from a mounted piezoelectric transducer into the surrounding air. Previous research on structures with indentations of power-law profile has focused on vibration mitigation using the so called "acoustic black-hole" effect, whereas here such structures are used to enhance ultrasonic radiation. The work provides experimental verification of the numerical results of Remillieux et al. (2014). PMID:26166628

  5. Models for the hotspot distribution

    SciTech Connect

    Jurdy, D.M. ); Stefanick, M. )

    1990-10-01

    Published hotspot catalogues 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 of the ridges is about what is expected.

  6. 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.

  7. 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.

  8. 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

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

    PubMed

    Shaw, Kerry L; Gillespie, Rosemary G

    2016-07-19

    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

  10. Hot-spot durability testing of amorphous cells and modules

    NASA Technical Reports Server (NTRS)

    Gonzalez, Charles; Jetter, Elizabeth

    1985-01-01

    This paper discusses the results of a study to determine the hot-spot susceptibility of amorphous-silicon (a-Si) cells and modules, and to provide guidelines for reducing that susceptibility. Amorphous-Si cells are shown to have hot-spot susceptibility levels similar to crystalline-silicon (C-Si) cells. This premise leads to the fact that the same general guidelines must apply to protecting a-Si cells from hot-spot stressing that apply to C-Si cells. Recommendations are made on ways of reducing a-Si module hot-spot susceptibility including the traditional method of using bypass diodes and a new method unique to thin-film cells, limiting the string current by limiting cell area.

  11. Linking the Galapagos hotspot and the Caribbean Plateau

    NASA Astrophysics Data System (ADS)

    Nerlich, Rainer; Clark, Stuart R.; Bunge, Hans-Peter

    2014-05-01

    Wide agreement exists that the Caribbean plate has a Pacific origin and that parts of it depict an igneous Plateau of up to 20 km thick crust. However, the origin of this thickened crust remains debated. One of the first suggestions for its origin was the arrival of a plume, whose remnant might be the Galapagos hotspot. More recently, it has been argued that reconstruction models predicted the Galapagos hotspot a thousand or more kilometres away from the Caribbean plate at the time of Plateau formation (~88 ?? 94 Ma). These authors primarily relied on the Caribbean Plateau moving into its present position relative to the Americas only in the last few million years. Secondarily, the authors assumed that the hotspot was fixed in an Indian-Atlantic hotspot reference frame. Here, we explore the idea that the Plateau moved into position around the time of the initiation of convergence between the North and South America, about 54.5 Ma. In addition, we adopt a fixed Pacific hotspot reference frame and compare our results to the recently developed Global Moving Hotspot Reference Frame. We show that both frames lead to good correlations between the paleo-positions of the Caribbean Plate and the Galapagos hotspot. As this result is consistent with abundant geochemical evidence that lends support for both a plume origin as well as the similarity between the Galapagos hotspot and rocks from the Plateau itself, we argue that alternative mechanisms to explain the thickened crust of the Caribbean Plateau are unnecessary. Additionally, based on our new plate reconstruction model, we present an age distribution of the lithosphere underneath the thickened crust of the Caribbean Plateau that has remained speculative until now.

  12. 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

  13. 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; Rose, Fred; Zhang, Yuanchong; Wilson Michael J.; Rossow, William

    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

  14. 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.

  15. Stable recombination hotspots in birds

    PubMed Central

    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

    2016-01-01

    The DNA-binding protein PRDM9 has a critical role in specifying meiotic recombination hotspots in mice and apes, but appears to be absent from other vertebrate species, including birds. To study the evolution and determinants of recombination in species lacking 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 find that both species have hotspots, which are enriched near functional genomic elements. Unlike in mice and apes, the two species share most hotspots, with conservation seemingly extending 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. PMID:26586757

  16. 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. PMID:26586757

  17. 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

  18. 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.

  19. 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.

  20. 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.

  1. 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.

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

    SciTech Connect

    Oreopoulos, L.; Mlawer, Eli J.; Delamere, Jennifer; Shippert, Timothy R.; Cole, Jason; Fomin, Boris; Iacono, Michael J.; Jin, Zhonghai; Li, Jiangning; Manners, James; Raisanen, Petri; Rose, Fred; Zhang, Yuanchong; Wilson, Michael J.; Rossow, William B.

    2012-01-01

    We present results from Phase I of the Continual Intercomparison of Radiation Codes (CIRC), intended as an evolving and regularly updated reference source for evaluation of radiative transfer (RT) codes used in Global Climate Models. CIRC differs from previous intercomparisons in that it relies on an observationally validated catalogue of cases. The seven CIRC Phase I baseline cases, five cloud-free, and two with overcast liquid clouds, are built around observations by the Atmospheric Radiation Measurements (ARM) program that satisfy the goals of Phase I, namely to examine radiative transfer (RT) model performance in realistic, yet not overly complex, atmospheric conditions. In addition to the seven baseline cases, additional idealized "subcases" are also examined to facilitate intrepretation of the causes of model errors. In addition to summarizing individual model performance with respect to reference line-by-line calculations and inter-model differences, we also highlight RT model behavior for conditions of doubled CO2, aspects of utilizing a spectral specification of surface albedo, and the impact of the inclusion of scattering in the thermal infrared. Our analysis suggests that RT models should work towards improving their calculation of diffuse shortwave flux, shortwave absorption, treatment of spectral surface albedo, and shortwave CO2 forcing. On the other hand, LW calculations appear to be significantly closer to the reference results. By enhancing the range of conditions under which participating codes are tested, future CIRC phases will hopefully allow even more rigorous examination of RT code performance.

  3. 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.

  4. 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.

  5. 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

  6. 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.

  7. Results from radiation monitoring equipment experiment on STS-8

    NASA Astrophysics Data System (ADS)

    Madonna, R. G.; Amico, R. L.; Brown, V. L.; Kidd, V. R.

    1984-07-01

    The results from the Radiation Equipment Monitoring (RME) experiment, flown onboard STS-8 are presented and discussed. The RME consists of the HRM-III gamma ray counter and PRM neutron/proton dosimeter. The gamma ray data agree wtih data from previous flights. Large increases in count rates are observed when the Orbiter is in the South Atlantic Anomaly. Neutron/proton dosage is consistent with NASA predictions for STS-8.

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. 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.

  13. 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. PMID:26232568

  14. 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.

  15. Outlier Detection on Hotspots Data in Riau Province using DBSCAN Algorithm

    NASA Astrophysics Data System (ADS)

    Sukmasetya, Pristi; Sitanggang, Imas S.

    2016-01-01

    Indonesia has serious problems in forest fires. One of the potential factors which indicates forest fires is hotspot. Hotspot is a forest fires indicator that detects a location with relatively higher temperature in comparison with nearby positions. One possible prevention efforts for forest fires is by detecting outliers on hotspots data. This study detects outlier on hotspots data in Riau Province in between year 2001 to 2012 using the DBSCAN algorithm and determines the distribution of outlier hotspots by region and time. The experiment results show that the highest occurrence of outliers is in 2005. The number of outliers on hotspots data reaches 1241 hotspots with the sum of square error (SSE) is 0.084. Outlier hotspots in Riau Province in 2005 spread across 11 districts/cities and 136 districts. In 2005 the highest outlier are found in Rokan Hulu with the number of outliers is 186 points. The highest frequency of hotspot that is considered as outliers is found in August 2005, with a total of 355 outliers in which as many 97 of these outliers are occurred in Rokan Hulu District.

  16. 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

  17. Study of hotspot repair using cellular automata method

    NASA Astrophysics Data System (ADS)

    Nagase, Norimasa; Takeuchi, Kanji; Sakurai, Mitsuo; Itoh, Takahisa; Okada, Tomoyuki

    2014-07-01

    In advanced semiconductor manufacturing, model-based optical proximity correction is commonly used to compensate for image errors. The final pattern is generated using correction values determined by lithography simulation. Image errors such as patterns with insufficient correction or patterns with excessive correction can be generated. These patterns with errors are called hotspots. Such errors are conventionally detected by lithography simulation of OPC patterns. When a hotspot is detected by lithography simulation, it has to be repaired manually or by repeated use of OPC tool. However, it is difficult to obtain correct pattern for a complicated shape, and the correction procedure may require a significant amount of additional processing. In order to solve this issue, we examine application of cellular automata (CA) method for hotspot correction. It is known that CA method can be used for weather or traffic analysis and prediction. In this report, we studied the CA method for deriving simple hotspot repair rule based on lattice cell-like models for light intensity distribution and OPC patterns. We will report on the results of hotspot correction technique with the OPC pattern using CA method.

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

    PubMed

    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

  19. 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.

  20. 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

  1. 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

  2. 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. PMID:24391250

  3. 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.

  4. The Earth Radiation Budget Experiment - Early validation results

    NASA Technical Reports Server (NTRS)

    Smith, G. L.; Barkstrom, B. R.; Harrison, E. F.; Huck, F. O.; Cess, R.; Coakley, J.; Duncan, C.; King, M.; Mecherikunnel, A.; Gruber, A.

    1986-01-01

    The primary techniques used to obtain and validate the data of the Earth Radiation Budget Experiment (ERBE) are described, together with preliminary results of the validation. The ERBE consists of radiometers aboard the ERB Satellite, dedicated to a 57-deg orbit, and each of the two NOAA meteorological spacecraft (NOAA 9 and NOAA G) in near polar orbits. The radiometers include scanning narrow field-of-view (FOV) and nadir-looking wide and medium FOV radiometers, and a solar monitoring channel. Measurements of the solar constant by the solar monitors, and the wide and medium FOV radiometers of the ERB and the NOAA 9 spacecraft agree within a fraction of a percent. Comparison of the wide and medium FOV radiometers with the scanning radiometers showed an agreement of 1 to 4 percent. The multiple ERBE satellites are acquiring the first global measurements of regional scale-diurnal variations in the earth's radiation budget. These were verified by comparison with the high-temporal-resolution geostationary satellite data.

  5. 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.

  6. 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.

  7. Contrasted patterns of hyperdiversification in Mediterranean hotspots.

    PubMed

    Sauquet, Hervé; Weston, Peter H; Anderson, Cajsa Lisa; Barker, Nigel P; Cantrill, David J; Mast, Austin R; Savolainen, Vincent

    2009-01-01

    Dating the Tree of Life has now become central to relating patterns of biodiversity to key processes in Earth history such as plate tectonics and climate change. Regions with a Mediterranean climate have long been noted for their exceptional species richness and high endemism. How and when these biota assembled can only be answered with a good understanding of the sequence of divergence times for each of their components. A critical aspect of dating by using molecular sequence divergence is the incorporation of multiple suitable age constraints. Here, we show that only rigorous phylogenetic analysis of fossil taxa can lead to solid calibration and, in turn, stable age estimates, regardless of which of 3 relaxed clock-dating methods is used. We find that Proteaceae, a model plant group for the Mediterranean hotspots of the Southern Hemisphere with a very rich pollen fossil record, diversified under higher rates in the Cape Floristic Region and Southwest Australia than in any other area of their total distribution. Our results highlight key differences between Mediterranean hotspots and indicate that Southwest Australian biota are the most phylogenetically diverse but include numerous lineages with low diversification rates. PMID:19116275

  8. 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. PMID:27110645

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. How Radiation Oncologists Would Disclose Errors: Results of a Survey of Radiation Oncologists and Trainees

    SciTech Connect

    Evans, Suzanne B.; Yu, James B.; Chagpar, Anees

    2012-10-01

    Purpose: To analyze error disclosure attitudes of radiation oncologists and to correlate error disclosure beliefs with survey-assessed disclosure behavior. Methods and Materials: With institutional review board exemption, an anonymous online survey was devised. An email invitation was sent to radiation oncologists (American Society for Radiation Oncology [ASTRO] gold medal winners, program directors and chair persons of academic institutions, and former ASTRO lecturers) and residents. A disclosure score was calculated based on the number or full, partial, or no disclosure responses chosen to the vignette-based questions, and correlation was attempted with attitudes toward error disclosure. Results: The survey received 176 responses: 94.8% of respondents considered themselves more likely to disclose in the setting of a serious medical error; 72.7% of respondents did not feel it mattered who was responsible for the error in deciding to disclose, and 3.9% felt more likely to disclose if someone else was responsible; 38.0% of respondents felt that disclosure increased the likelihood of a lawsuit, and 32.4% felt disclosure decreased the likelihood of lawsuit; 71.6% of respondents felt near misses should not be disclosed; 51.7% thought that minor errors should not be disclosed; 64.7% viewed disclosure as an opportunity for forgiveness from the patient; and 44.6% considered the patient's level of confidence in them to be a factor in disclosure. For a scenario that could be considerable, a non-harmful error, 78.9% of respondents would not contact the family. Respondents with high disclosure scores were more likely to feel that disclosure was an opportunity for forgiveness (P=.003) and to have never seen major medical errors (P=.004). Conclusions: The surveyed radiation oncologists chose to respond with full disclosure at a high rate, although ideal disclosure practices were not uniformly adhered to beyond the initial decision to disclose the occurrence of the error.

  15. 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.

  16. 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

  17. Radiative shocks on large scale lasers. Preliminary results

    NASA Astrophysics Data System (ADS)

    Leygnac, S.; Bouquet, S.; Stehle, C.; Barroso, P.; Batani, D.; Benuzzi, A.; Cathala, B.; Chièze, J.-P.; Fleury, X.; Grandjouan, N.; Grenier, J.; Hall, T.; Henry, E.; Koenig, M.; Lafon, J. P. J.; Malka, V.; Marchet, B.; Merdji, H.; Michaut, C.; Poles, L.; Thais, F.

    2001-05-01

    Radiative shocks, those structure is strongly influenced by the radiation field, are present in various astrophysical objects (circumstellar envelopes of variable stars, supernovae ...). Their modeling is very difficult and thus will take benefit from experimental informations. This approach is now possible using large scale lasers. Preliminary experiments have been performed with the nanosecond LULI laser at Ecole Polytechnique (France) in 2000. A radiative shock has been obtained in a low pressure xenon cell. The preparation of such experiments and their interpretation is performed using analytical calculations and numerical simulations.

  18. Application of terahertz radiation to soil measurements: initial results.

    PubMed

    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

  19. 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.

  20. Summary of current radiation dosimetry results on manned spacecraft

    NASA Technical Reports Server (NTRS)

    Benton, E. V.

    1984-01-01

    It is pointed out that the experimental data existing on radiation levels inside orbiting spacecraft are currently limited. However, it is recognized that perhaps the single most important constraint to long-term manned space activity may be related to the complex space radiation environment. For this reason, it is important to know the radiological parameters which determine the biological effects of space radiation on humans. Attention is given to radiation dose measurements, LET (linear energy transfer) spectra for HZE particles, and dosimetry data from U.S. manned spaceflights. In particular, data are now available on dose rates in spacecraft at low altitudes (less than 300 km), while insufficient measurements exist for high altitude and high inclination orbits, geostationary orbits, and many orbits in between. Very little data exist on neutron dose and spectra.

  1. 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.

  2. 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

  3. Detecting Recombination Hotspots from Patterns of Linkage Disequilibrium.

    PubMed

    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

  4. 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

  5. Interpretation of the high conductive anomaly of the Society hotspot

    NASA Astrophysics Data System (ADS)

    Tada, Noriko; Tarits, Pascal; Baba, Kiyoshi; Utada, Hisashi; Suetsugu, Daisuke

    2016-04-01

    The mantle upwellings are one of the most important features for understanding the mantle dynamics. A large-scale mantle upwelling beneath the French Polynesia region in the South Pacific has been suggested from seismic studies, which is called the South Pacific superplume, and a slow velocity anomaly continues from the core mantle boundary to the upper mantle just beneath the Society hotspot (e.g., Suetsugu et al., 2009). However, the previous studies are not enough to understand the geometry, temperature, and composition of the Society hotspot. Then, we carried out the TIARES project that composed of multi-sensor stations that include broadband ocean bottom seismometers, ocean bottom electromagnetometers (OBEMs), and differential pressure gauges from 2009 to 2010 (Suetsugu et al., 2012). We have analyzed marine magnetotelluric data obtained totally 20 sites around the Society hotspot, and revealed a three-dimensional shaped high conductive anomaly, like a thumb, beneath the Society hotspot (see detail in session GD8.3/EMRP4.9/SM7.6). In order to clarify the cause of the high conductivity, water content, melt fraction, and H2O and CO2 contents in the upper mantle were estimated by adopting results of rock experiments at high temperatures and pressures. As a result, the upper mantle in the high conductive anomaly involves more water, melt, H2O, and CO2 rather than that in the surrounding area. Furthermore, temperature of high conductive anomaly might be higher than the surrounding area.

  6. Central Indian Ridge and Reunion Hotspot in Rodrigues Area : Another Type of Ridge - Hotspot Interaction ?

    NASA Astrophysics Data System (ADS)

    DYMENT, J.; HEMOND, C.; GUILLOU, H.; MAIA, M.; BRIAIS, A.; GENTE, P.

    2001-12-01

    The Rodrigues Ridge is an E-W volcanic structure which extends at 19° S from the Mascarene Plateau (59° 30'E) to 100 km East of Rodrigues Island (64° 30'E). It is neither parallel to seafloor spreading flow-lines nor to the "absolute" motion of Africa in the hotspot reference frame. 39Ar-40Ar dating of dredged samples has shown that the whole ridge formed at 8-10 Ma, suggesting a rather rapid emplacement between the former position of the Reunion hotspot and the nearest segment of the CIR at 10-8 Ma. This rules out the hypothesis that the Rodrigues Ridge was progressively built near the CIR axis, at the end of a "channeled" asthenospheric flow originating from Reunion hotspot. Sr, Nd and Pb isotopes show gradual fading of the Reunion hotspot influence with increasing distance from the Mascarene Plateau. Signs for a more recent activity are the Rodrigues Island, dated about 1 Ma, and a set of recently discovered en-echelon volcanic ridges, the Three Magi and Gasitao Ridges. They extend the Rodrigues Ridge up to the CIR axis. These ridges display a clear sigmoid shape and align along an E-W direction at 19° 40'S. Another parallel, less prominent volcanic alignment is observed about 30 km north, at 19° 25'S. K-Ar dating (Cassignol method) provides ages of 0.4 and 1.8 Ma for the easternmost Gasitao Ridge. This second age is slightly younger than that of the underlying crust given by the magnetic anomalies. Isotopic compositions are intermediate between those measured on Rodrigues Ridge and the CIR axis. The lack of conjugate bathymetric feature and the age measured on the Gasitao Ridge demonstrate that it was built off axis, in the close vicinity of the CIR. The sigmoid morphology and en-echelon alignment of Three Magi and Gasitao Ridges suggest that they correspond to tension cracks filled by magmas resulting from decompression melting of underlying mantle. Repetition of such magmatic events results in increasing volume as ridges get older, in agreement with the

  7. 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.

  8. 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.

  9. 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

  10. 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

  11. 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. PMID:24066162

  12. 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

  13. 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.

  14. 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.

  15. 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.

  16. 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

  17. 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

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

    PubMed

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

    2010-03-01

    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. PMID:20176972

  19. 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.

  20. Transport implications of hydrodynamic mix on hot-spot performance in inertial confinement fusion

    NASA Astrophysics Data System (ADS)

    Srinivasan, Bhuvana; Tang, Xianzhu

    2014-10-01

    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 the 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. We quantify this mix-enhanced transport effect on hot-spot fusion-performance degradation using contrasting 1-D and 2-D hydrodynamic simulations, and identify its dependence on effective acceleration, Atwood number, and ablation speed. In the presence of magnetic fields, the thermal conduction is reduced which reduces the effect of ablative stabilization on mix mitigation while also reducing the amount of cold fuel being ablated into the hot-spot. A characterization of the transport enhanced mix characteristics with and without magnetic fields is performed to identify a regime where fusion-performance degradation is reduced by mix mitigation, through which the amount of cold fuel being ablated into the hot-spot is minimized.

  1. 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

    2015-07-01

    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

  2. Results of a Division of Radiation Protection scrap yard exercise.

    PubMed

    James, J D

    2001-02-01

    For years the Division of Radiation Protection (DRP) has participated in exercises, which are required by the Federal Emergency Management Agency (FEMA) to demonstrate our ability to deal with an accident at a nuclear power plant. These demonstrations are defined by objectives and are structured such that they offer little opportunity to practice for real-world radiological events in the exercise. Since real-world radiological incidents do occur throughout the year, this exercise was designed to be as realistic as possible. A scrap yard incident was chosen as the most probable type of event. The exercise was conducted on May 5 and 6, 1999. PMID:11197512

  3. Hot-Spot Mix in Ignition-Scale Implosions at the National Ignition Facility

    NASA Astrophysics Data System (ADS)

    Regan, S. P.

    2011-10-01

    Ignition of an inertial confinement fusion 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 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.The 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 < λ < 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 mass-equivalent CH layer, was examined. The amount of hot-spot mix mass, estimated from the Ge K-shell line brightness using a detailed atomic physics code, is typically below the 100-ng allowance for hot-spot mix.1 Predictions of a simple mix model, based on linear growth of the measured surface-mass modulations, are consistent with the experimental results. The measured dependence of hot-spot mix on the implosion velocity and on the high-mode ablator-surface perturbations will be presented. This work was supported by the U.S. Department of Energy Office of Inertial Confinement Fusion under Cooperative Agreement No. DE-FC52-08NA28302. In collaboration with the National Ignition Campaign Mix Working Group. S. W. Haan et. al., Phys. Plasmas 18, 051001 (2011>).

  4. Summary of current radiation dosimetry results on manned spacecraft

    NASA Astrophysics Data System (ADS)

    Benton, E. V.

    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° versus 28.5° 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 on previous shuttle missions. A dose rate more than an order of magnitude higher than for any other space shuttle flight was obtained for mission STS-41C, reflecting the highest orbital altitude to date of 519 km.

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

    NASA Astrophysics Data System (ADS)

    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. Flight sample mutation rate was approximately 8-fold higher than ground controls which exhibited laboratory spontaneous frequencies.

  6. 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. PMID:11540032

  7. 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.

  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. The Measurement of Hot-spots in Granulated Ammonium Nitrate

    NASA Astrophysics Data System (ADS)

    Proud, William; Field, John

    2001-06-01

    Ammonium Nitrate (AN) is one of the components of the most widely used explosive in the world ammonium nitrate: fuel oil mixtures (ANFO). By itself, it is an oxygen negative explosive with a large critical diameter. Hot-spots are produced in explosives by various means including gas space collapse, localised shear or friction. If these hot-spots reach critical conditions of size, temperature and duration size reaction can grow. This deflagration stage may eventually transition to detonation. This paper describes a system and presents results where high-speed image intensified photography is used to monitor the number and growth of hot spots in granular AN under a range of different impact pressures. The results can be used in detonation codes to provide a more accurate and realistic description of the initiation process.

  10. 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

  11. 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

  12. The Measurement of Hot-Spots in Granulated Ammonium Nitrate

    NASA Astrophysics Data System (ADS)

    Proud, W. G.

    2002-07-01

    Ammonium Nitrate (AN) is one of the components of the most widely used explosive in the world namely, ammonium nitrate: fuel oil mixtures (ANFO). By itself, it is an oxygen positive explosive with a large critical diameter. Hot-spots are produced in explosives by various means including gas space collapse, localised shear or friction. If these hot-spots reach critical conditions of size, temperature and duration reaction can grow. This deflagration stage may eventually transition to detonation. This paper describes high-speed image-intensified photography study in which the number and growth of hot spots in granular AN are monitored for a range of different impact pressures. The results can be used in detonation codes to provide a more accurate and realistic description of the initiation process.

  13. 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

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

    PubMed Central

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

    2014-01-01

    The ability to examine all chromatids from a single meiosis in yeast tetrads has been indispensable for defining 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 conversions, 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. PMID:25151354

  15. 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.

  16. 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.

  17. 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. PMID:26991854

  18. 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. PMID:12907699

  19. 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

  20. Probing Hotspot Conditions in Spherically Shock Compressed Matter

    NASA Astrophysics Data System (ADS)

    Bachmann, Benjamin; Nilsen, J.; Kritcher, A. L.; Swift, D.; Rygg, J. R.; Collins, G. W.; Divol, L.; Falcone, R. W.; Gaffney, J.; Glenzer, S. H.; Hatarik, R.; Hawreliak, J.; Khan, S.; Kraus, D.; Landen, O. L.; Masters, N.; Nagel, S. R.; Pardini, T.; Zimmerman, G.; Doeppner, T.

    2015-11-01

    We present results of an approach to experimentally determine the conditions in the center of a CD2 sphere that has been compressed to petapascal pressures by spherically converging shocks. By measuring the hotspot size using penumbral imaging, hotspot temperature using two-color spectroscopy, the neutron yield from DD nuclear reactions and the x-ray burn width, we infer average hotspot densities of 43 g/cm3 at 1.6 keV temperature. These conditions correspond to pressures of 4.4 petapascal (44 Gbar) in an ideal gas and 3.5 petapascal from independently performed rad.-hydro. simulations. The experimentally determined neutron yield, temperature and density constrain the EOS in a regime that exceeds previously reported pressures obtained in carbon EOS measurements by three orders of magnitude. The results show a path for constraining the EOS of matter at conditions that have been inaccessible with state-of-the-art experimental EOS techniques. This work was performed under the auspices of the U.S. DOE by LLNL under Contract DE-AC52-07NA27344 and LDRD Grant 13-ERD-073

  1. 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.

  2. 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

  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. 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.

  5. 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. PMID:17841084

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. Results of the Association of Directors of Radiation Oncology Programs (ADROP) Survey of Radiation Oncology Residency Program Directors

    SciTech Connect

    Harris, Eleanor Abdel-Wahab, May; Spangler, Ann E.; Lawton, Colleen A.; Amdur, Robert J.

    2009-06-01

    Purpose: To survey the radiation oncology residency program directors on the topics of departmental and institutional support systems, residency program structure, Accreditation Council for Graduate Medical Education (ACGME) requirements, and challenges as program director. Methods: A survey was developed and distributed by the leadership of the Association of Directors of Radiation Oncology Programs to all radiation oncology program directors. Summary statistics, medians, and ranges were collated from responses. Results: Radiation oncology program directors had implemented all current required aspects of the ACGME Outcome Project into their training curriculum. Didactic curricula were similar across programs nationally, but research requirements and resources varied widely. Program directors responded that implementation of the ACGME Outcome Project and the external review process were among their greatest challenges. Protected time was the top priority for program directors. Conclusions: The Association of Directors of Radiation Oncology Programs recommends that all radiation oncology program directors have protected time and an administrative stipend to support their important administrative and educational role. Departments and institutions should provide adequate and equitable resources to the program directors and residents to meet increasingly demanding training program requirements.

  12. 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.

  13. 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. PMID:23759207

  14. 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.

  15. 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.

  16. 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

  17. 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

  18. 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

  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. 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.

  1. Results and toxicity of the treatment of anal canal carcinoma by radiation therapy or radiation therapy and chemotherapy.

    PubMed

    Cummings, B; Keane, T; Thomas, G; Harwood, A; Rider, W

    1984-11-15

    The results of treating anal canal carcinoma by radical external beam radiation alone (RT) or by combined 5-fluorouracil, mitomycin C and radiation (FUMIR), were compared in nonrandomized groups of patients treated in a single center. In each treatment regimen, surgery was reserved for those patients with residual carcinoma. The uncorrected 5-year survival rate in each group was approximately 70%, but primary tumor control was achieved in 93% (28/30) with FUMIR compared to 60% (15/25) treated with RT. Acute hematologic and enterocolic toxicity with uninterrupted external beam radiation courses of 5000 cGy in 4 weeks plus chemotherapy led to the adoption of split-course treatment. Serious late toxicity requiring surgical intervention occurred in 3 of 25 following RT, and in 5 of 30 following FUMIR. Colostomies were needed as part of treatment for residual carcinoma or for the management of treatment-related toxicity in 11 of 25 treated by RT and have been required to date in 4 of 30 treated by FUMIR. The improvement in the primary tumor control rate and the reduction in the number of patients requiring colostomy when compared with the results of RT favor combined chemotherapy and radiation as the initial treatment for anal canal carcinoma. PMID:6435851

  2. 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.

  3. 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.

    2016-05-01

    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.

  4. 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 micro Gauss. 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.

  5. 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.

  6. 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. PMID:26345622

  7. 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

  8. RESULTS OF THE NASA SPACE RADIATION LABORATORY BEAM STUDIES PROGRAM AT BNL.

    SciTech Connect

    BROWN,K.A.AHRENS,L.BEUTTENMULLER,R.H.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 NSRL makes use of heavy ions in the range of 0.05 to 3 GeV/n slow extracted from BNL's AGS Booster. The purpose of the NSRL Beam Studies Program is to develop a clear understanding of the beams delivered to the facility, to fully characterize those beams, and to develop new capabilities in the interest of understanding the radiation environment in space. In this report we will describe the first results from this program.

  9. 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

  10. 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.

  11. Depth-based hotspot identification and multivariate ranking using the full Bayes approach.

    PubMed

    El-Basyouny, Karim; Sayed, Tarek

    2013-01-01

    Although the multivariate structure of traffic accidents has been recognized in the safety literature for over a decade now, univariate identification and ranking of hotspots is still dominant. The present paper advocates the use of multivariate identification and ranking of hotspots based on statistical depth functions, which are useful tools for non-parametric multivariate analysis as they provide center-out ordering of multivariate data. Thus, a depth-based multivariate method is proposed for the identification and ranking of hotspots using the full Bayes (FB) approach. The proposed method is applied to a sample of 236 signalized intersections in the Greater Vancouver Area. Various multivariate Poisson log-normal (MVPLN) models were used for data analysis. For each model, the FB posterior estimates were obtained using the Markov Chains Monte Carlo (MCMC) techniques and several goodness-of-fit measures were used for model selection. Using a depth threshold of 0.025, the proposed method identified 26 intersections (11%) as potential hotspots. The choice of a depth threshold is a delicate decision and it is suggested to determine the threshold according to the amount of funding available for safety improvement, which is the usual practice in univariate hotspot identification (HSID). Also, the results show that the performance of the proposed multivariate depth-based FB HSID method is superior to that of an analogous method based on the depths of accident frequency (AF) in terms of sensitivity, specificity and the sum of norms (lengths) of Poisson mean vectors. PMID:23018036

  12. Four individually druggable MET hotspots mediate HGF-driven tumor progression

    PubMed Central

    Basilico, Cristina; Hultberg, Anna; Blanchetot, Christophe; de Jonge, Natalie; Festjens, Els; Hanssens, Valérie; Osepa, Sjudry-Ilona; De Boeck, Gitte; Mira, Alessia; Cazzanti, Manuela; Morello, Virginia; Dreier, Torsten; Saunders, Michael; de Haard, Hans; Michieli, Paolo

    2014-01-01

    Activation of MET by HGF plays a key role in tumor progression. Using a recently developed llama platform that generates human-like immunoglobulins, we selected 68 different antibodies that compete with HGF for binding to MET. HGF-competing antibodies recognized 4 distinct hotspots localized in different MET domains. We identified 1 hotspot that coincides with the known HGF β chain binding site on blades 2–3 of the SEMA domain β-propeller. We determined that a second and a third hotspot lie within blade 5 of the SEMA domain and IPT domains 2–3, both of which are thought to bind to HGF α chain. Characterization of the fourth hotspot revealed a region across the PSI-IPT 1 domains not previously associated with HGF binding. Individual or combined targeting of these hotspots effectively interrupted HGF/MET signaling in multiple cell-based biochemical and biological assays. Selected antibodies directed against SEMA blades 2–3 and the PSI-IPT 1 region inhibited brain invasion and prolonged survival in a glioblastoma multiforme model, prevented metastatic disease following neoadjuvant therapy in a triple-negative mammary carcinoma model, and suppressed cancer cell dissemination to the liver in a KRAS-mutant metastatic colorectal cancer model. These results identify multiple regions of MET responsible for HGF-mediated tumor progression, unraveling the complexity of HGF-MET interaction, and provide selective molecular tools for targeting MET activity in cancer. PMID:24865428

  13. 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.

  14. Identifying Genetic Hotspots by Mapping Molecular Diversity of Widespread Trees: When Commonness Matters.

    PubMed

    Souto, Cintia P; Mathiasen, Paula; Acosta, María Cristina; Quiroga, María Paula; Vidal-Russell, Romina; Echeverría, Cristian; Premoli, Andrea C

    2015-01-01

    Conservation planning requires setting priorities at the same spatial scale at which decision-making processes are undertaken considering all levels of biodiversity, but current methods for identifying biodiversity hotspots ignore its genetic component. We developed a fine-scale approach based on the definition of genetic hotspots, which have high genetic diversity and unique variants that represent their evolutionary potential and evolutionary novelties. Our hypothesis is that wide-ranging taxa with similar ecological tolerances, yet of phylogenetically independent lineages, have been and currently are shaped by ecological and evolutionary forces that result in geographically concordant genetic patterns. We mapped previously published genetic diversity and unique variants of biparentally inherited markers and chloroplast sequences for 9 species from 188 and 275 populations, respectively, of the 4 woody dominant families of the austral temperate forest, an area considered a biodiversity hotspot. Spatial distribution patterns of genetic polymorphisms differed among taxa according to their ecological tolerances. Eight genetic hotspots were detected and we recommend conservation actions for some in the southern Coastal Range in Chile. Existing spatially explicit genetic data from multiple populations and species can help to identify biodiversity hotspots and guide conservation actions to establish science-based protected areas that will preserve the evolutionary potential of key habitats and species. PMID:26245788

  15. A novel approach for hot-spot removal for sub-100nm manufacturing

    NASA Astrophysics Data System (ADS)

    Ma, Melody; Anderson, Melissa; Lai, Weinong; Wu, Clive; Tsao, Becky; Chu, Chih-wei; Lin, Char; Chou, Jacky; Tsai, Sidney

    2006-10-01

    Recent advances in lithography simulation have made full-chip lithography rule checking (LRC) practical and even mandatory for many fabs, especially those operating with half-pitches under 100nm. These LRCs routinely identify marginal or even fatal manufacturability problems (hot-spots), especially when simulated through process corners. Until recently, when hot-spots were identified, the only options were to reject the tapeout for additional layout modifications, re-run OPC with a different recipe, or use a DRC-tool to do "blind" cut-and-paste repairs under the assumption that making fatal errors non-fatal is sufficient to make them "good." Using a commercial LRC tool, we will inspect OPC data on a production design to identify a typical volume of real and potential hot-spots. Next, using Halo-Fix from Aprio Technologies, we will apply local repairs, choosing rule-based or model-based repair strategies as appropriate for each type of hot-spot. Using this method, "intelligent" changes in the hot-spot areas can be made which accurately account for lithography interactions and process variations, in order to optimize for manufacturing robustness. To verify that the repairs are acceptable, LRCs will be performed and the results analyzed.

  16. 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.

  17. Radiation induction of drug resistance in RIF-1: Correlation of tumor and cell culture results

    SciTech Connect

    Moulder, J.E.; Hopwood, L.E.; Volk, D.M.; Davies, B.M. )

    1991-02-01

    The RIF-1 tumor line contains cells that are resistant to various anti-neoplastic drugs, including 5-fluorouracil (5FU), methotrexate (MTX), adriamycin (ADR), and etoposide (VP16). The frequency of these drug-resistant cells is increased after irradiation. The frequency of drug-resistant cells and the magnitude of radiation-induced drug resistance are different in cell culture than in tumors. The dose-response and expression time relationships for radiation induction of drug resistance observed in RIF-1 tumors are unusual.We hypothesize that at high radiation doses in vivo, we are selecting for cells that are both drug resistant and radiation resistant due to microenvironmental factors, whereas at low radiation doses in vivo and all radiation doses in vitro, we are observing true mutants. These studies indicate that there can be significant differences in drug-resistance frequencies between tumors and their cell lines of origin, and that radiation induction of drug resistance depends significantly on whether the induction is done in tumors or in cell culture. These results imply that theories about the induction of drug resistance that are based on cell culture studies may be inapplicable to the induction of drug resistance in tumors.

  18. Amifostine (ETHYOL) protects rats from mucositis resulting from fractionated or hyperfractionated radiation exposure

    SciTech Connect

    Cassatt, David R.; McCarthy, Michael P. . E-mail: mccarthym@medimmune.com

    2005-03-01

    Purpose: The cytoprotective drug amifostine (Ethyol) protects rats from oral mucositis resulting from a single dose of {gamma}-irradiation. We expanded earlier studies to determine whether multiple doses of amifostine protect against fractionated or hyperfractionated radiation and whether the active metabolite of amifostine (WR-1065) accumulates in tissues upon repeated administration. Methods and materials: Rats received amifostine daily for 5 days in conjunction with a 1-week fractionated radiation schedule and were evaluated for oral mucositis. Rats also received amifostine before the am or pm exposure or b.i.d. in conjunction with hyperfractionated radiation. To determine the pharmacokinetics of WR-1065 after repeated dosing, amifostine was given 5 days a week for 1 or 3 weeks, and rat tissue and plasma were collected at intervals during and after treatment and analyzed for WR-1065. Results: Amifostine protected rats from mucositis resulting from fractionated or hyperfractionated radiation. When the number of days of amifostine administration was reduced, protection was diminished. A dose of 100 mg/kg given in the morning or 2 doses at 50 mg/kg provided the best protection against hyperfractionated radiation. WR-1065 did not accumulate in tissues or tumor upon repeated administration. Conclusions: Amifostine prevented radiation-induced mucositis in a rat model; protection was dose and schedule dependent.

  19. 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

  20. 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

  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. 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

  3. Molecular architecture of transcription factor hotspots in early adipogenesis.

    PubMed

    Siersbæk, Rasmus; Baek, Songjoon; Rabiee, Atefeh; Nielsen, Ronni; Traynor, Sofie; Clark, Nicholas; Sandelin, Albin; Jensen, Ole N; Sung, Myong-Hee; Hager, Gordon L; Mandrup, Susanne

    2014-06-12

    Transcription factors have recently been shown to colocalize in hotspot regions of the genome, which are further clustered into super-enhancers. However, the detailed molecular organization of transcription factors at hotspot regions is poorly defined. Here, we have used digital genomic footprinting to precisely define factor localization at a genome-wide level during the early phase of 3T3-L1 adipocyte differentiation, which allows us to obtain detailed molecular insight into how transcription factors target hotspots. We demonstrate the formation of ATF-C/EBP heterodimers at a composite motif on chromatin, and we suggest that this may be a general mechanism for integrating external signals on chromatin. Furthermore, we find evidence of extensive recruitment of transcription factors to hotspots through alternative mechanisms not involving their known motifs and demonstrate that these alternative binding events are functionally important for hotspot formation and activity. Taken together, these findings provide a framework for understanding transcription factor cooperativity in hotspots. PMID:24857666

  4. Porous Au-Ag Nanospheres with High-Density and Highly Accessible Hotspots for SERS Analysis.

    PubMed

    Liu, Kai; Bai, Yaocai; Zhang, Lei; Yang, Zhongbo; Fan, Qikui; Zheng, Haoquan; Yin, Yadong; Gao, Chuanbo

    2016-06-01

    Colloidal plasmonic metal nanoparticles have enabled surface-enhanced Raman scattering (SERS) for a variety of analytical applications. While great efforts have been made to create hotspots for amplifying Raman signals, it remains a great challenge to ensure their high density and accessibility for improved sensitivity of the analysis. Here we report a dealloying process for the fabrication of porous Au-Ag alloy nanoparticles containing abundant inherent hotspots, which were encased in ultrathin hollow silica shells so that the need of conventional organic capping ligands for stabilization is eliminated, producing colloidal plasmonic nanoparticles with clean surface and thus high accessibility of the hotspots. As a result, these novel nanostructures show excellent SERS activity with an enhancement factor of ∼1.3 × 10(7) on a single particle basis (off-resonant condition), promising high applicability in many SERS-based analytical and biomedical applications. PMID:27192436

  5. 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. PMID:24106496

  6. 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

  7. Results of radiation hardness tests and performance tests of the HS9008RH flash ADC

    SciTech Connect

    Nutter, S.; Tarle, G. . Physics Dept.); Crawley, H.B.; McKay, R.; Meyer, W.T.; Rosenberg, E.I.; Thomas, W.D. . Dept. of Physics and Astronomy Ames Lab., IA )

    1994-08-01

    Results from tests characterizing the performance and radiation hardness of the HS9008RH flash analog to digital converter (FADC) are presented. These tests were performed primarily to evaluate the suitability of this device for use in the GEM Central Tracker at the SSC experiment. Basic performance characteristics and susceptibility of these characteristics to radiation were examined. Performance test results indicate that the device integral nonlinearity is sampling rate dependent and worsens rapidly above rate of 15 megasamples per second (MSPS). No degradation in performance of the device was observed after its exposure of up to 81 Mrad of 1.25 MeV [gamma] radiation from a [sup 60]Co source. Exposure of the device to a reactor fast neutron fluence (E > 100keV) of 5 [times] 10[sup 14]/cm[sup 2] resulted in no significant observed performance degradation as well.

  8. 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

  9. SU-E-T-200: IBA ProteusOne Compact Proton Therapy System Radiation Survey Results

    SciTech Connect

    Zhang, J; Syh, J; Syh, J; White, M; Patel, B; Song, X; Wu, H

    2014-06-01

    Purpose: This study summarizes the results of an initial radiation survey of the Willis-Knighton Cancer Center in Shreveport, Louisiana. The facility houses an IBA ProteusOne compact single room proton therapy unit coupled with a C230 cyclotron that operates at a maximum energy of 230 MeV. Methods: A calibrated survey meter was used for the photon measurements to obtain reliable results. A neutron detector was used as the measuring instrument for neutrons. The locations of the survey and measurements were planned carefully in order to get a proper evaluation of the facility shielding configuration. The walls, ceiling, vault entrance, and the adjacent environment were each surveyed with suitable measurement instruments. A total of 22 locations were chosen for radiation survey. Dose equivalent values were calculated for both the photon and the neutron radiation using measured data. Results: All measured dose values are presented in millisievert per year. The highest dose measured at the vault entrance is 0.34 mSv/year. A dedicated shielding door was not present at the time of the measurement. The vault entrance area is considered as a controlled area. The shielding design goals are not to exceed 5 mSv/year for the controlled area and 1 mSv/year the uncontrolled area. The total combined neutron and photon dose equivalent values were found to be compliant with the Louisiana Department of Environmental Quality radiation protection regulatory codes. Conclusion: In our efforts to evaluate the radiation levels at the Willis-Knighton Cancer Center proton treatment facility, we have found that all the measured values of the radiation shielding are below the critical radiation limits per year. Since the total dose measured at the vault entrance is below the shielding design goal, a shielding door is not required at this proton treatment vault.

  10. 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.

  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. PMID:23635866

  12. Hotspots of nitrous oxide and methane flux in urban watersheds

    NASA Astrophysics Data System (ADS)

    Groffman, P. M.; Bettez, N. D.; Duncan, J. M.; Band, L. E.

    2012-12-01

    Urban and suburban watersheds have spatially and temporally dynamic soil, vegetation and hydrologic conditions that create a marked "hotspot" distribution of trace gas fluxes. In the Baltimore Ecosystem Study, one of two urban long-term ecological research (LTER) projects funded by the U.S. National Science Foundation, we have established long-term study plots in forests, grasslands (lawns), wetlands and riparian zones and have made monthly in situ measurements of carbon dioxide, nitrous oxide and methane flux since 1998. These long-term observations have produced several interesting results. First, there is marked variation in methane flux, with rural forest having higher uptake than urban forests and lawns having no uptake. Nitrous oxide fluxes are lower than expected given high rates of atmospheric deposition to forests and fertilization of lawns. However, key landscape features such as degraded riparian zones, stormwater detention basin wetlands and natural hummock and hollow riparian wetlands are hotspots of nitrous oxide and/or methane production. These features can be detected and quantified using new geographic characterization techniques (LiDAR, topographic index) and then modeled using ecohydrological models (RHESSys). Combining long-term biogeochemical measurements with these new geographic and modeling tools can improve our understanding and quantification of trace gas fluxes from urban ecosystems.

  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. 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.

  15. [Inversion of LAI by considering the hotspot effect for different geometrical wheat].

    PubMed

    Zhao, Juan; Zhang, Yao-Hong; Huang, Wen-Jiang; Jing, Yuan-Shu; Peng, Dai-Liang; Wang, Li; Song, Xiao-Yu

    2014-01-01

    Aimed to deal with the limitation of canopy geometry to crop LAI inversion accuracy a new LAI inversion method for different geometrical winter wheat was proposed based on hotspot indices with field-measured experimental data. The present paper analyzed bidirectional reflectance characteristics of erective and loose varieties at red (680 nm) and NIR wavelengths (800 nm and 860 nm) and developed modified normalized difference between hotspot and dark-spot (MNDHD) and hotspot and dark-spot ratio index (HDRI) using hotspot and dark-spot index (HDS) and normalized difference between hotspot and dark-spot (NDHD) for reference. Combined indices were proposed in the form of the product between HDS, NDHD, MNDHD, HDRI and three ordinary vegetation indices NDVI, SR and EVI to inverse LAI for erective and loose wheat. The analysis results showed that LAI inversion accuracy of erective wheat Jing411 were 0.9431 and 0.9092 retrieved from the combined indices between NDVI and MNDHD and HDRI at 860 nm which were better than that of HDS and NDHD, the LAI inversion accuracy of loose wheat Zhongyou9507 were 0.9648 and 0.8956 retrieved from the combined indices between SR and HDRI and MNDHD at 800 nm which were also higher than that of HDS and NDHD. It was finally concluded that the combined indices between hotspot-signature indices and ordinary vegetation indices were feasible enough to inverse LAI for different crop geometrical wheat and multiangle remote sensing data was much more advantageous than perpendicular observation data to extract crop structural parameters. PMID:24783562

  16. 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

  17. 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.

  18. Verification of radiative transfer results by inserting them into the RTE: A demonstration for Rayleigh scattering

    NASA Astrophysics Data System (ADS)

    Hollstein, André

    2012-10-01

    The verification of a new or updated radiative transfer model (RTM) is one of the important steps in its development; this is usually achieved by comparisons with real measurements or published tables of generally accepted radiative transfer results. If such tables do not exist, verification becomes more complicated and an external review of the implementation is often unpractical due to the sheer amount and complexity of the code. The presented verification approach is to “simply” insert results of radiative transfer (RT) calculations into the radiative transfer equation (RTE). The evaluation of the RTE consists of numerically calculating partial derivatives and integrals, which is much simpler to implement than a solution of the RTE. Presented is a demonstration of this approach for a case of Rayleigh scattering in a plane parallel atmosphere, which showed only very small deviation from the radiative transfer equation.This approach has two key benefits. First, its implementation into a high level computer language can be very short (≈60 lines in MATHEMATICA) and clear compared to a full RTM; and such code is much more easy to review. Second, this approach can be easily extended to cases where no other independent RT implementation is available for validation. The proposed implementation and data are provided with this paper.

  19. 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

  20. 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. PMID:25469426

  1. Upscaling methane emission hotspots in boreal peatlands

    NASA Astrophysics Data System (ADS)

    Cresto Aleina, Fabio; Runkle, Benjamin R. K.; Brücher, Tim; Kleinen, Thomas; Brovkin, Victor

    2016-03-01

    Upscaling the properties and effects of small-scale surface heterogeneities to larger scales is a challenging issue in land surface modeling. We developed a novel approach to upscale local methane emissions in a boreal peatland from the micro-topographic scale to the landscape scale. We based this new parameterization on the analysis of the water table pattern generated by the Hummock-Hollow model, a micro-topography resolving model for peatland hydrology. We introduce this parameterization of methane hotspots in a global model-like version of the Hummock-Hollow model that underestimates methane emissions. We tested the robustness of the parameterization by simulating methane emissions for the next century, forcing the model with three different RCP scenarios. The Hotspot parameterization, despite being calibrated for the 1976-2005 climatology, mimics the output of the micro-topography resolving model for all the simulated scenarios. The new approach bridges the scale gap of methane emissions between this version of the model and the configuration explicitly resolving micro-topography.

  2. Upscaling methane emission hotspots in boreal peatlands

    NASA Astrophysics Data System (ADS)

    Cresto Aleina, F.; Runkle, B. R. K.; Brücher, T.; Kleinen, T.; Brovkin, V.

    2015-10-01

    Upscaling the properties and the effects of small-scale surface heterogeneities to larger scales is a challenging issue in land surface modeling. We developed a novel approach to upscale local methane emissions in a boreal peatland from the micro-topographic scale to the landscape-scale. We based this new parameterization on the analysis of the water table pattern generated by the Hummock-Hollow model, a micro-topography resolving model for peatland hydrology. We introduce this parameterization of methane hotspots in a global model-like version of the Hummock-Hollow model, that underestimates methane emissions. We tested the robustness of the parameterization by simulating methane emissions for the next century forcing the model with three different RCP scenarios. The Hotspot parameterization, despite being calibrated for the 1976-2005 climatology, mimics the output of the micro-topography resolving model for all the simulated scenarios. The new approach bridges the scale gap of methane emissions between this version of the model and the configuration explicitly resolving micro-topography.

  3. Recent results in the radiation synthesis and modification of polymers for special applications

    SciTech Connect

    Hummel, D.O.

    1980-01-01

    Certain economic considerations relative to production of radicals on a large-industrial scale using different types of radiation indicate that current use of electron accelerators in at least 9 out of 10 radiation-chemical processes reflects use of the most economical method of irradiation. Fluorine-containing monomers and monomer mixtures belong to a class of systems intensively studied for the radiation-initiated synthesis of polymers with good thermal, mechanical, and chemical properties. Results of detailed investigations of the vinylfluoride-vinylidene-fluoride system and subsequent grafting with hydrophylic monomers are presented. Studies of grafting in the system polyethylene-hexafluoroacetone was found to follow a chain mechanism, with the branches consisting of only one monomer unit each. Cationic grafting was observed during irradiation of ..cap alpha..-methylstyrene, vinylbutylether, or isobutene in the presence of polyethylene, polytetrafluoroethylene, or PVC. Grafting of the fiber/monomer systems, cellulose with styrene, vinylfluoride, ethylacrylate or acrylamide; wool with styrene; polypropylene with vinylchloride and vinylidenechloride; poly(ethylene terephthalate) with styrene, acrylic and methacrylic acid, acrylic acid plus acrylonitrile, and N-vinylpyrrolidone have all been investigated recently. Radiation synthesis and modification of membranes and resins and the radiation-grafting of enzymes have also been reported. 75 references. (BLM)

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. 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.

  10. Performance characteristics and radiation damage results from the Fermilab E706 silicon microstrip detector system

    NASA Astrophysics Data System (ADS)

    Engels, E.; Mani, S.; Orris, D.; Shepard, P. F.; Weerasundara, P. D.; Choudhary, B. C.; Joshi, U.; Kapoor, V.; Shivpuri, R.; Baker, W.; Berg, D.; Carey, D.; Johnstone, C.; Nelson, C.; Bromberg, C.; Brown, D.; Huston, J.; Miller, R.; Nguyen, A.; Benson, R.; Lukens, P.; Ruddick, K.; Alverson, G.; Faissler, W.; Garelick, D.; Glaubman, M.; Kourbanis, I.; Lirakis, C.; Pothier, E.; Sinanidis, A.; Wu, G.-H.; Yasuda, T.; Yosef, C.; Easo, S.; Hartman, K.; Oh, B. Y.; Toothacker, W.; Whitmore, J.; Ballocchi, G.; Debarbaro, L.; Desoi, W.; Fanourakis, G.; Ferbel, T.; Ginther, G.; Gutierrez, P.; Lanaro, A.; Lobkowicz, F.; Mansour, J.; Pedeville, G.; Prebys, E.; Skow, D.; Slattery, P.; Varelas, N.; Zielinski, M.

    1989-07-01

    A charged particle spectrometer containing a 7120-channel silicon microstrip detector system, one component of Fermilab experiment E706 to study direct photon production in hadron-hadron collisions, was utilized in a run in which 6 million events were recorded. We describe the silicon system, provide early results of track and vertex reconstruction, and present data on the radiation damage to the silicon wafers resulting from the narrow high intensity beam.

  11. 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

  12. 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.

  13. Radiation Transfer Model Intercomparison (RAMI) exercise: Results from the second phase

    NASA Astrophysics Data System (ADS)

    Pinty, B.; Widlowski, J.-L.; Taberner, M.; Gobron, N.; Verstraete, M. M.; Disney, M.; Gascon, F.; Gastellu, J.-P.; Jiang, L.; Kuusk, A.; Lewis, P.; Li, X.; Ni-Meister, W.; Nilson, T.; North, P.; Qin, W.; Su, L.; Tang, S.; Thompson, R.; Verhoef, W.; Wang, H.; Wang, J.; Yan, G.; Zang, H.

    2004-03-01

    The Radiation Transfer Model Intercomparison (RAMI) initiative is a community-driven exercise to benchmark the models of radiation transfer (RT) used to represent the reflectance of terrestrial surfaces. Systematic model intercomparisons started in 1999 as a self-organized, open-access, voluntary activity of the RT modeling community. The results of the first phase were published by [2001]. The present paper describes the benchmarking protocol and the results achieved during the second phase, which took place during 2002. This second phase included two major components: The first one included a rerun of all direct-mode tests proposed during the first phase, to accommodate the evaluation of models that have been upgraded since, and the participation of new models into the entire exercise. The second component was designed to probe the performance of three-dimensional models in complex heterogeneous environments, which closely mimic the observations of actual space instruments operating at various spatial resolutions over forest canopy systems. Phases 1 and 2 of RAMI both confirm not only that a majority of the radiation transfer models participating in RAMI are in good agreement between themselves for relatively simple radiation transfer problems but also that these models exhibit significant discrepancies when considering more complex but nevertheless realistic geophysical scenarios. Specific recommendations are provided to guide the future of this benchmarking program (Phase 3 and beyond).

  14. 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. PMID:26177624

  15. 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. PMID:24020492

  16. The Manihiki Plateau - a key to missing hotspot tracks?

    NASA Astrophysics Data System (ADS)

    Pietsch, R.; Uenzelmann-Neben, G.

    2016-04-01

    A Neogene magmatic reactivation of the Manihiki Plateau, a Large Igneous Province (LIP) in the central Pacific, is studied using seismic reflection data. Igneous diapirs have been identified exclusively within a narrow WNW-ESE striking corridor in the southern High Plateau (HP), which is parallel to the Neogene Pacific Plate motion and overlaps with an extrapolation of the Society Islands Hotspot path. The igneous diapirs are characterized by a narrow width (>5 km), penetration of the Neogene sediments, and they become progressively younger towards the East (23-10 Ma). The magmatic source appears to be of small lateral extent, which leads to the conclusion that the diapirs represent Neogene hotspot volcanism within a LIP, and thus may be an older, previously unknown extension of the Society Islands Hotspot track (>4.5 Ma). Comparing hotspot volcanism within oceanic and continental lithosphere, we further conclude that hotspot volcanism within LIP crust has similarities to tectonically faulted continental crust.

  17. 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

  18. Identification of genomic functional hotspots with copy number alteration in liver cancer

    PubMed Central

    2013-01-01

    Copy number alterations (CNAs) can be observed in most of cancer patients. Several oncogenes and tumor suppressor genes with CNAs have been identified in different kinds of tumor. However, the systematic survey of CNA-affected functions is still lack. By employing systems biology approaches, instead of examining individual genes, we directly identified the functional hotspots on human genome. A total of 838 hotspots on human genome with 540 enriched Gene Ontology functions were identified. Seventy-six aCGH array data of hepatocellular carcinoma (HCC) tumors were employed in this study. A total of 150 regions which putatively affected by CNAs and the encoded functions were identified. Our results indicate that two immune related hotspots had copy number alterations in most of patients. In addition, our data implied that these immune-related regions might be involved in HCC oncogenesis. Also, we identified 39 hotspots of which copy number status were associated with patient survival. Our data implied that copy number alterations of the regions may contribute in the dysregulation of the encoded functions. These results further demonstrated that our method enables researchers to survey biological functions of CNAs and to construct regulation hypothesis at pathway and functional levels. PMID:24160471

  19. 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%).

  20. 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

  1. 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. PMID:21844048

  2. 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

  3. 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.

  4. Upscaling methane emission hotspots in boreal peatlands

    NASA Astrophysics Data System (ADS)

    Cresto Aleina, Fabio; Runkle, Benjamin R. K.; Bruecher, Tim; Kleinen, Thomas; Brovkin, Victor

    2016-04-01

    Small-scale surface heterogeneities can influence land-atmosphere fluxes and therefore carbon, water and energy budgets on a larger scale. This effect is of particular relevance for high-latitude ecosystems, because of the great amount of carbon stored in their soils. Upscaling such small-scale surface heterogeneities and their effects to larger scales is a challenging issue in land surface modeling. We developed a novel approach to upscale local methane emissions in a boreal peatland from the micro-topographic scale to the landscape-scale. We based this parameterization on the analysis of the water table pattern generated by the Hummock-Hollow model (Cresto Aleina et al., 2015), a micro-topography resolving model for peatland hydrology and methane emissions. By computing the water table at the micro-topographic scale, the Hummock-Hollow model is able to describe the effects of micro-topography on hydrology and methane emissions in a typical boreal peatland. We introduce the new parameterization of methane hotspots in a global model-like version of the Hummock-Hollow model. This latter version underestimates methane emissions because of the lack of representation of micro-topographic controls on peatland hydrology. We tested the robustness of the parameterization by simulating methane emissions for the present day and for the next century, forcing the model with three different RCP scenarios. The Hotspot parameterization, despite being calibrated for the 1976-2005 climatology, mimics the output of the micro-topography resolving model for all the simulated scenarios. The new approach bridges the scale gap of methane emissions between this version of the model and the configuration explicitly resolving micro-topography.

  5. 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.

  6. Urban rivers as hotspots of regional nitrogen pollution.

    PubMed

    Zhang, Xiaohong; Wu, Yiyun; Gu, Baojing

    2015-10-01

    Excess nitrogen inputs to terrestrial ecosystems via human activities have deteriorated water qualities on regional scales. Urban areas as settlements of over half global population, however, were usually not considered in the analysis of regional water pollution. Here, we used a 72-month monitoring data of water qualities in Hangzhou, China to test the role of urban rives in regional nitrogen pollution and how they response to the changes of human activities. Concentrations of ammonium nitrogen in urban rivers were 3-5 times higher than that in regional rivers. Urban rivers have become pools of reactive nitrogen and hotspots of regional pollution. Moreover, this river pollution is not being measured by current surface water monitoring networks that are designed to measure broader regional patterns, resulting in an underestimation of regional pollution. This is crucial to urban environment not only in China, but also in other countries, where urban rivers are seriously polluted. PMID:26057476

  7. Lagrangian Hotspots of In-Use NOX Emissions from Transit Buses.

    PubMed

    Kotz, Andrew J; Kittelson, David B; Northrop, William F

    2016-06-01

    In-use, spatiotemporal NOX emissions were measured from a conventional powertrain transit bus and a series electric hybrid bus over gradients of route kinetic intensity and ambient temperature. This paper introduces a new method for identifying NOX emissions hotspots along a bus route using high fidelity Lagrangian vehicle data to explore spatial interactions that may influence emissions production. Our study shows that the studied transit buses emit higher than regulated emissions because on-route operation does not accurately represent the range of engine operation tested according to regulatory standards. Using the Lagrangian hotspot detection, we demonstrate that NOX hotspots occurred at bus stops, during cold starts, on inclines, and for accelerations. On the selected routes, bus stops resulted in 3.3 times the route averaged emissions factor in grams/km without significant dependence on bus type or climate. The buses also emitted 2.3 times the route averaged NOX emissions factor at the beginning of each route due to cold selective catalytic reduction aftertreatment temperature. The Lagrangian hotspot detection technique demonstrated here could be employed in future connected vehicles empowered by advances in computational power, data storage capability, and improved sensor technology to optimize emissions as a function of spatial location. PMID:27135811

  8. Hotspots, Lifelines, and the Safrr Haywired Earthquake Sequence

    NASA Astrophysics Data System (ADS)

    Ratliff, J. L.; Porter, K.

    2014-12-01

    Though California has experienced many large earthquakes (San Francisco, 1906; Loma Prieta, 1989; Northridge, 1994), the San Francisco Bay Area has not had a damaging earthquake for 25 years. Earthquake risk and surging reliance on smartphones and the Internet to handle everyday tasks raise the question: is an increasingly technology-reliant Bay Area prepared for potential infrastructure impacts caused by a major earthquake? How will a major earthquake on the Hayward Fault affect lifelines (roads, power, water, communication, etc.)? The U.S. Geological Survey Science Application for Risk Reduction (SAFRR) program's Haywired disaster scenario, a hypothetical two-year earthquake sequence triggered by a M7.05 mainshock on the Hayward Fault, addresses these and other questions. We explore four geographic aspects of lifeline damage from earthquakes: (1) geographic lifeline concentrations, (2) areas where lifelines pass through high shaking or potential ground-failure zones, (3) areas with diminished lifeline service demand due to severe building damage, and (4) areas with increased lifeline service demand due to displaced residents and businesses. Potential mainshock lifeline vulnerability and spatial demand changes will be discerned by superimposing earthquake shaking, liquefaction probability, and landslide probability damage thresholds with lifeline concentrations and with large-capacity shelters. Intersecting high hazard levels and lifeline clusters represent potential lifeline susceptibility hotspots. We will also analyze possible temporal vulnerability and demand changes using an aftershock shaking threshold. The results of this analysis will inform regional lifeline resilience initiatives and response and recovery planning, as well as reveal potential redundancies and weaknesses for Bay Area lifelines. Identified spatial and temporal hotspots can provide stakeholders with a reference for possible systemic vulnerability resulting from an earthquake sequence.

  9. Future of Endemic Flora of Biodiversity Hotspots in India

    PubMed Central

    Chitale, Vishwas Sudhir; Behera, Mukund Dev; Roy, Partha Sarthi

    2014-01-01

    India is one of the 12 mega biodiversity countries of the world, which represents 11% of world's flora in about 2.4% of global land mass. Approximately 28% of the total Indian flora and 33% of angiosperms occurring in India are endemic. Higher human population density in biodiversity hotspots in India puts undue pressure on these sensitive eco-regions. In the present study, we predict the future distribution of 637 endemic plant species from three biodiversity hotspots in India; Himalaya, Western Ghats, Indo-Burma, based on A1B scenario for year 2050 and 2080. We develop individual variable based models as well as mixed models in MaxEnt by combining ten least co-related bioclimatic variables, two disturbance variables and one physiography variable as predictor variables. The projected changes suggest that the endemic flora will be adversely impacted, even under such a moderate climate scenario. The future distribution is predicted to shift in northern and north-eastern direction in Himalaya and Indo-Burma, while in southern and south-western direction in Western Ghats, due to cooler climatic conditions in these regions. In the future distribution of endemic plants, we observe a significant shift and reduction in the distribution range compared to the present distribution. The model predicts a 23.99% range reduction and a 7.70% range expansion in future distribution by 2050, while a 41.34% range reduction and a 24.10% range expansion by 2080. Integration of disturbance and physiography variables along with bioclimatic variables in the models improved the prediction accuracy. Mixed models provide most accurate results for most of the combinations of climatic and non-climatic variables as compared to individual variable based models. We conclude that a) regions with cooler climates and higher moisture availability could serve as refugia for endemic plants in future climatic conditions; b) mixed models provide more accurate results, compared to single variable based

  10. Future of endemic flora of biodiversity hotspots in India.

    PubMed

    Chitale, Vishwas Sudhir; Behera, Mukund Dev; Roy, Partha Sarthi

    2014-01-01

    India is one of the 12 mega biodiversity countries of the world, which represents 11% of world's flora in about 2.4% of global land mass. Approximately 28% of the total Indian flora and 33% of angiosperms occurring in India are endemic. Higher human population density in biodiversity hotspots in India puts undue pressure on these sensitive eco-regions. In the present study, we predict the future distribution of 637 endemic plant species from three biodiversity hotspots in India; Himalaya, Western Ghats, Indo-Burma, based on A1B scenario for year 2050 and 2080. We develop individual variable based models as well as mixed models in MaxEnt by combining ten least co-related bioclimatic variables, two disturbance variables and one physiography variable as predictor variables. The projected changes suggest that the endemic flora will be adversely impacted, even under such a moderate climate scenario. The future distribution is predicted to shift in northern and north-eastern direction in Himalaya and Indo-Burma, while in southern and south-western direction in Western Ghats, due to cooler climatic conditions in these regions. In the future distribution of endemic plants, we observe a significant shift and reduction in the distribution range compared to the present distribution. The model predicts a 23.99% range reduction and a 7.70% range expansion in future distribution by 2050, while a 41.34% range reduction and a 24.10% range expansion by 2080. Integration of disturbance and physiography variables along with bioclimatic variables in the models improved the prediction accuracy. Mixed models provide most accurate results for most of the combinations of climatic and non-climatic variables as compared to individual variable based models. We conclude that a) regions with cooler climates and higher moisture availability could serve as refugia for endemic plants in future climatic conditions; b) mixed models provide more accurate results, compared to single variable based

  11. 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.

  12. 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.

  13. Effects of Canary hotspot volcanism on structure of oceanic crust off Morocco

    NASA Astrophysics Data System (ADS)

    Holik, James S.; Rabinowitz, Philip D.; Austin, James A., Jr.

    1991-07-01

    Analysis of over 6400 km of multichannel seismics (MCS) and 50 sonobuoy reflection and refraction experiments reduced both in the domain of X-T and tau-p shows that a region within the Jurassic Quiet Zone off Morocco underwent dramatic changes as a result of the passage of the lithosphere over the Canary hotspot commencing approximately 60 Ma. A seismic unit (UCF), interpreted as volcanic in origin, is observed within the sediments in a region characterized by a broad bathymetric swell. It shows diffractions from its upper surface and an internally chaotic seismic facies and pinches out between sedimentary units of continuous, subparallel facies. A velocity inversion is noted between the UCF (4.7km/s) and the underlying sediment (3.1 km/s). The UCF is time transgressive; it lies near the Cretaceous/s Tertiary boundary in the northern portion of the study area and is younger to the south. Kinematic studies of the movement of the Canary hotspot relative to Africa show that the hotspot first appeared off NW Africa about 60 Ma and was located beneath oceanic crust in the region where the UCF is observed. Depth-to-basement measurements in areas not effected by the hotspot show a consistent linear trend of increased depth with age. In areas effected by the hotspot the thermal rejuvenation is evident as basement depths shoal with increased proximity to the present hotspot. The reheating of the crust resets the thermal age of the lithosphere with many of the properties of crust of a younger age. Subsidence curves of the reheated crust off Morocco show good correlation to subsidence curves of other reheated crust on a global basis. A zone characterized by high crustal velocities, (7.1-7.4 km/s) and greater crustal thicknesses (by ˜1-2 km) is observed in an area that corresponds to the bathymetric swell, the region of the UCF, and the reelevated basement. The high velocities and increased crustal thickness are interpreted to be the result of underplating and assimilation of

  14. Modelling Hotspots for Invasive Alien Plants in India.

    PubMed

    Adhikari, Dibyendu; Tiwary, Raghuvar; Barik, Saroj Kanta

    2015-01-01

    Identification of invasion hotspots that support multiple invasive alien species (IAS) is a pre-requisite for control and management of invasion. However, till recently it remained a methodological challenge to precisely determine such invasive hotspots. We identified the hotspots of alien species invasion in India through Ecological Niche Modelling (ENM) using species occurrence data from the Global Biodiversity Information Facility (GBIF). The predicted area of invasion for selected species were classified into 4 categories based on number of model agreements for a region i.e. high, medium, low and very low. About 49% of the total geographical area of India was predicted to be prone to invasion at moderate to high levels of climatic suitability. The intersection of anthropogenic biomes and ecoregions with the regions of 'high' climatic suitability was classified as hotspot of alien plant invasion. Nineteen of 47 ecoregions of India, harboured such hotspots. Most ecologically sensitive regions of India, including the 'biodiversity hotspots' and coastal regions coincide with invasion hotspots, indicating their vulnerability to alien plant invasion. Besides demonstrating the usefulness of ENM and open source data for IAS management, the present study provides a knowledge base for guiding the formulation of an effective policy and management strategy for controlling the invasive alien species. PMID:26230513

  15. Modelling Hotspots for Invasive Alien Plants in India

    PubMed Central

    Adhikari, Dibyendu; Tiwary, Raghuvar; Barik, Saroj Kanta

    2015-01-01

    Identification of invasion hotspots that support multiple invasive alien species (IAS) is a pre-requisite for control and management of invasion. However, till recently it remained a methodological challenge to precisely determine such invasive hotspots. We identified the hotspots of alien species invasion in India through Ecological Niche Modelling (ENM) using species occurrence data from the Global Biodiversity Information Facility (GBIF). The predicted area of invasion for selected species were classified into 4 categories based on number of model agreements for a region i.e. high, medium, low and very low. About 49% of the total geographical area of India was predicted to be prone to invasion at moderate to high levels of climatic suitability. The intersection of anthropogenic biomes and ecoregions with the regions of 'high' climatic suitability was classified as hotspot of alien plant invasion. Nineteen of 47 ecoregions of India, harboured such hotspots. Most ecologically sensitive regions of India, including the 'biodiversity hotspots' and coastal regions coincide with invasion hotspots, indicating their vulnerability to alien plant invasion. Besides demonstrating the usefulness of ENM and open source data for IAS management, the present study provides a knowledge base for guiding the formulation of an effective policy and management strategy for controlling the invasive alien species. PMID:26230513

  16. 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.

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

    PubMed

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

    2000-06-01

    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. PMID:11543368

  18. Ecohydrological Interfaces as Dynamic Hotspots of Biogeochemical Cycling

    NASA Astrophysics Data System (ADS)

    Krause, S.

    2015-12-01

    Ecohydrological interfaces, represent the boundaries between water-dependent ecosystems that can alter substantially the fluxes of energy and matter. There is still a critical gap of understanding the organisational principles of the drivers and controls of spatially and temporally variable ecohydrological interface functions. This knowledge gap limits our capacity to efficiently quantify, predict and manage the services provided by complex ecosystems. Many ecohydrological interfaces are characterized by step changes in microbial metabolic activity, steep redox gradients and often even thermodynamic phase shifts, for instance at the interfaces between atmosphere and water or soil matrix and macro-pores interfaces. This paper integrates investigations from point scale microcosm experiments with reach and subcatchment scale tracer experiments and numerical modeling studies to elaborate similarities in the drivers and controls that constitute the enhanced biogeochemical activity of different types of ecohydrologica interfaces across a range of spatial and temporal scales. We therefore combine smart metabolic activity tracers to quantify the impact of bioturbating benthic fauna onto ecosystem respiration and oxygen consumption and investigate at larger scale, how microbial metabolic activity and carbon turnover at the water-sediment interface are controlled by sediment physical and chemical properties as well as water temperatures. Numerical modeling confirmed that experimentally identified hotspots of streambed biogeochemical cycling were controlled by patterns of physical properties such as hydraulic conductivities or bioavailability of organic matter, impacting on residence time distributions and hence reaction times. In contrast to previous research, our investigations thus confirmed that small-scale variability of physical and chemical interface properties had a major impact on biogeochemical processing at the investigated ecohydrological interfaces. Our results

  19. Ecohydrological Interfaces as Dynamic Hotspots of Biogeochemical Cycling

    NASA Astrophysics Data System (ADS)

    Krause, Stefan; Lewandowski, Joerg; Hannah, David; McDonald, Karlie; Folegot, Silvia; Baranov, Victor

    2016-04-01

    . Our results furthermore indicate that to fully understand spatial patterns and temporal dynamics of ecohydrological interface functioning, including hotspots and hot moments, detailed knowledge of the impacts of biological behavior on the physic-chemical ecosystem conditions, and vice-versa, is required.

  20. 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 et al., Phys. Plasmas 18, 051001 (2011)]. 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 [D. S. Clark et al., Phys. Plasmas 17, 052703 (2010)]. Richtmyer-Meshkov and Rayleigh-Taylor hydrodynamic instabilities seeded by high-mode () ablator-surface perturbations can cause Ge-doped ablator to mix into the interior of the shell at the end of the acceleration phase [B. A. Hammel et al., Phys. Plasmas 18, 056310 (2011)]. 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 deuterium-tritium (DT) cryogenic targets and gas-filled plastic-shell capsules, which replace the THD layer with a mass-equivalent 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 [J. J. MacFarlane et al., High Energy Density Phys. 3, 181 (2006)], is typically below the 75-ng allowance for hot-spot mix [S. W. Haan et al., Phys. Plasmas 18, 051001 (2011)]. Predictions of a simple mix model, based on linear growth of the measured surface-mass modulations, are consistent with the experimental results.

  1. Hot-spot mix in ignition-scale implosions on the NIFa)

    NASA Astrophysics Data System (ADS)

    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.

    2012-05-01

    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 et al., Phys. Plasmas 18, 051001 (2011)]. 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 [D. S. Clark et al., Phys. Plasmas 17, 052703 (2010)]. Richtmyer-Meshkov and Rayleigh-Taylor hydrodynamic instabilities seeded by high-mode (50<ℓ<200) ablator-surface perturbations can cause Ge-doped ablator to mix into the interior of the shell at the end of the acceleration phase [B. A. Hammel et al., Phys. Plasmas 18, 056310 (2011)]. 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 deuterium-tritium (DT) cryogenic targets and gas-filled plastic-shell capsules, which replace the THD layer with a mass-equivalent 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 [J. J. MacFarlane et al., High Energy Density Phys. 3, 181 (2006)], is typically below the 75-ng allowance for hot-spot mix [S. W. Haan et al., Phys. Plasmas 18, 051001 (2011)]. Predictions of a simple mix model, based on linear growth of the measured surface-mass modulations, are consistent with the experimental results.

  2. Conservative surgery for low rectal carcinoma after high-dose radiation. Functional and oncologic results.

    PubMed Central

    Rouanet, P; Fabre, J M; Dubois, J B; Dravet, F; Saint Aubert, B; Pradel, J; Ychou, M; Solassol, C; Pujol, H

    1995-01-01

    OBJECTIVE: Using a prospective, nonrandomized study, the authors evaluated the morbidity and functional and oncologic results of conservative surgery for cancer of the lower third of the rectum after high-dose radiation. SUMMARY BACKGROUND DATA: Colo-anal anastomosis has made sphincter conservation for low rectal carcinoma technically feasible. The limits to conservative surgery currently are oncologic rather than technical. Adjuvant radiotherapy has proven its benefit in terms of regional control, with a dose relationship. METHODS: Since June 1990, 27 patients with distal rectal adenocarcinoma were treated by preoperative radiotherapy (40 + 20 Gy delivered with three fields) and curative surgery. The mean distance from the anal verge was 47 mm (27-57 mm), and none of the tumors were fixed (15 T2, 12 T3). RESULTS: Mortality and morbidity were not increased by high-dose preoperative radiation. Twenty-one patients underwent conservative surgery (78%-17 total proctectomies and colo-anal anastomoses, 4 trans-anal resections). After colo-anal anastomosis, all patients with colonic pouch had good results; two patients had moderate results and one patient had poor results after straight colo-anal anastomosis. With a mean follow-up of 24 months, the authors noted 1 postoperative death, 2 disease-linked deaths, 1 controlled regional recurrence, 2 evolutive patients with pulmonary metastases, and 21 disease-free patients. CONCLUSIONS: These first results confirm the possibility of conservative surgery for low rectal carcinoma after high-dose radiation. A prospective, randomized trial could be induced to determine the real role of the 20 Gy boost on the sphincter-saving decision. PMID:7826163

  3. Late rectal and bladder toxicity following radiation therapy for prostate cancer: Predictive factors and treatment results

    PubMed Central

    Fuentes-Raspall, Rafael; Inoriza, José Maria; Rosello-Serrano, Alvaro; Auñón-Sanz, Carmen; Garcia-Martin, Pilar; Oliu-Isern, Gemma

    2013-01-01

    Aim This study aimed at investigating factors associated to late rectal and bladder toxicity following radiation therapy and the effectiveness of Hyperbaric Oxygen Therapy (HBOT) when toxicity is grade ≥2. Background Radiation is frequently used for prostate cancer, but a 5–20% incidence of late radiation proctitis and cystitis exists. Some clinical and dosimetric factors have been defined without a full agreement. For patients diagnosed of late chronic proctitis and/or cystitis grade ≥2 treatment is not well defined. Hyperbaric Oxygen Therapy (HBOT) has been used, but its effectiveness is not well known. Materials and methods 257 patients were treated with radiation therapy for prostate cancer. Clinical, pharmacological and dosimetric parameters were collected. Patients having a grade ≥2 toxicity were treated with HBOT. Results of the intervention were measured by monitoring toxicity by Common Toxicity Criteria v3 (CTCv3). Results Late rectal toxicity was related to the volume irradiated, i.e. V50 > 53.64 (p = 0.013); V60 > 38.59% (p = 0.005); V65 > 31.09% (p = 0.002) and V70 > 22.81% (p = 0.012). We could not correlate the volume for bladder. A total of 24 (9.3%) patients experienced a grade ≥2. Only the use of dicumarinic treatment was significant for late rectal toxicity (p = 0.014). A total of 14 patients needed HBOT. Final percentage of patients with a persistent toxicity grade ≥2 was 4.5%. Conclusion Rectal volume irradiated and dicumarinic treatment were associated to late rectal/bladder toxicity. When toxicity grade ≥2 is diagnosed, HBOT significantly ameliorate symptoms. PMID:24416567

  4. Three-dimensional hotspots in evaporating nanoparticle sols for ultrahigh Raman scattering: solid-liquid interface effects

    NASA Astrophysics Data System (ADS)

    Sun, Yudie; Han, Zhenzhen; Liu, Honglin; He, Shengnan; Yang, Liangbao; Liu, Jinhuai

    2015-04-01

    Three-dimensional (3D) hotspots for ultrahigh surface-enhanced Raman scattering (SERS) has been experimentally demonstrated by evaporating a droplet of citrate-Ag sols on both hydrophobic and hydrophilic flat surfaces. Interestingly, the hydrophobic surface increased the Raman enhancement by two orders of magnitude and exhibits a better signal stability than the hydrophilic one. This study highlights the differences between hydrophilic and hydrophobic surfaces in enhanced Raman scattering by the use of extremely diluted rhodamine 6G (R6G) as the SERS reporter. In situ synchrotron-radiation small-angle X-ray scattering (SR-SAXS) was employed to explore the evolution of the 3D geometry of Ag nanoparticles in a single droplet and verify the influence mechanism of these two kinds of surface. The ideal situation of 3D self-assembly of nanoparticles in the evaporation process is a collaborative behaviour, but our results evidenced that a progressive 3D self-assembly of nanoparticles was more preferred due to the interface effects. Our experimental data derived from in situ SR-SAXS reveals that a truly distinct 3D geometry of the Ag particles develops during the evaporation process on both hydrophilic and hydrophobic surfaces. In this type of 3D geometry, the increased uniformity of the interparticle distance induced a sharp peak of the SR-SAXS signal, differing significantly from the dry state. In particular, the fluorosilylated surface reduces the interaction with particles and decreases the electrostatic adsorption on the flat surface, which helps to control the interparticle distance to remain within a small range, produce a larger number of hotspots in 3D space, and amplify the SERS enhancement accordingly.Three-dimensional (3D) hotspots for ultrahigh surface-enhanced Raman scattering (SERS) has been experimentally demonstrated by evaporating a droplet of citrate-Ag sols on both hydrophobic and hydrophilic flat surfaces. Interestingly, the hydrophobic surface

  5. Effect of vortex hotspots on the radio-frequency surface resistance of superconductors

    SciTech Connect

    A. Gurevich, G. Ciovati

    2013-02-01

    We present detailed experimental and theoretical investigations of hotspots produced by trapped vortex bundles and their effect on the radio-frequency (rf) surface resistance R{sub s} of superconductors at low temperatures. Our measurements of R{sub s}, combined with the temperature mapping and laser scanning of a 2.36-mm-thick Nb plate incorporated into a 3.3-GHz Nb resonator cavity cooled by the superfluid He at 2 K, revealed spatial scales and temperature distributions of hotspots and showed that they can be moved or split by thermal gradients produced by the scanning laser beam. These results, along with the observed hysteretic field dependence of R{sub s} which can be tuned by the scanning laser beam, show that the hotspots in our Nb sample are due to trapped vortex bundles which contain ∼10{sup 6} vortices spread over regions ∼0.1–1 cm. We calculated the frequency dependence of the rf power dissipated by oscillating vortex segments trapped between nanoscale pinning centers, taking into account all bending modes and the nonlocal line tension of the vortex driven by rf Meissner currents. We also calculated the temperature distributions caused by trapped vortex hotspots, and suggested a method of reconstructing the spatial distribution of vortex dissipation sources from the observed temperature maps. Vortex hotspots can dominate the residual surface resistance at low temperatures and give rise to a significant dependence of R{sub s} on the rf field amplitude H{sub p}, which can have important implications for the rf resonating cavities used in particle accelerators and for thin-film structures used in quantum computing and photon detectors.

  6. Climate change hotspots in the CMIP5 global climate model ensemble.

    PubMed

    Diffenbaugh, Noah S; Giorgi, Filippo

    2012-01-10

    We use a statistical metric of multi-dimensional climate change to quantify the emergence of global climate change hotspots in the CMIP5 climate model ensemble. Our hotspot metric extends previous work through the inclusion of extreme seasonal temperature and precipitation, which exert critical influence on climate change impacts. The results identify areas of the Amazon, the Sahel and tropical West Africa, Indonesia, and the Tibetan Plateau as persistent regional climate change hotspots throughout the 21(st) century of the RCP8.5 and RCP4.5 forcing pathways. In addition, areas of southern Africa, the Mediterranean, the Arctic, and Central America/western North America also emerge as prominent regional climate change hotspots in response to intermediate and high levels of forcing. Comparisons of different periods of the two forcing pathways suggest that the pattern of aggregate change is fairly robust to the level of global warming below approximately 2°C of global warming (relative to the late-20(th)-century baseline), but not at the higher levels of global warming that occur in the late-21(st)-century period of the RCP8.5 pathway, with areas of southern Africa, the Mediterranean, and the Arctic exhibiting particular intensification of relative aggregate climate change in response to high levels of forcing. Although specific impacts will clearly be shaped by the interaction of climate change with human and biological vulnerabilities, our identification of climate change hotspots can help to inform mitigation and adaptation decisions by quantifying the rate, magnitude and causes of the aggregate climate response in different parts of the world. PMID:24014154

  7. A Chromosomal Rearrangement Hotspot Can Be Identified from Population Genetic Variation and Is Coincident with a Hotspot for Allelic Recombination

    PubMed Central

    Lindsay, Sarah J.; Khajavi, Mehrdad; Lupski, James R.; Hurles, Matthew E.

    2006-01-01

    Insights into the origins of structural variation and the mutational mechanisms underlying genomic disorders would be greatly improved by a genomewide map of hotspots of nonallelic homologous recombination (NAHR). Moreover, our understanding of sequence variation within the duplicated sequences that are substrates for NAHR lags far behind that of sequence variation within the single-copy portion of the genome. Perhaps the best-characterized NAHR hotspot lies within the 24-kb-long Charcot-Marie-Tooth disease type 1A (CMT1A)–repeats (REPs) that sponsor deletions and duplications that cause peripheral neuropathies. We investigated structural and sequence diversity within the CMT1A-REPs, both within and between species. We discovered a high frequency of retroelement insertions, accelerated sequence evolution after duplication, extensive paralogous gene conversion, and a greater than twofold enrichment of SNPs in humans relative to the genome average. We identified an allelic recombination hotspot underlying the known NAHR hotspot, which suggests that the two processes are intimately related. Finally, we used our data to develop a novel method for inferring the location of an NAHR hotspot from sequence variation within segmental duplications and applied it to identify a putative NAHR hotspot within the LCR22 repeats that sponsor velocardiofacial syndrome deletions. We propose that a large-scale project to map sequence variation within segmental duplications would reveal a wealth of novel chromosomal-rearrangement hotspots. PMID:17033965

  8. Detection of Tuberculosis Infection Hotspots Using Activity Spaces Based Spatial Approach in an Urban Tokyo, from 2003 to 2011

    PubMed Central

    Izumi, Kiyohiko; Ohkado, Akihiro; Uchimura, Kazuhiro; Murase, Yoshiro; Tatsumi, Yuriko; Kayebeta, Aya; Watanabe, Yu; Ishikawa, Nobukatsu

    2015-01-01

    Background Identifying ongoing tuberculosis infection sites is crucial for breaking chains of transmission in tuberculosis-prevalent urban areas. Previous studies have pointed out that detection of local accumulation of tuberculosis patients based on their residential addresses may be limited by a lack of matching between residences and tuberculosis infection sites. This study aimed to identify possible tuberculosis hotspots using TB genotype clustering statuses and a concept of “activity space”, a place where patients spend most of their waking hours. We further compared the spatial distribution by different residential statuses and describe urban environmental features of the detected hotspots. Methods Culture-positive tuberculosis patients notified to Shinjuku city from 2003 to 2011 were enrolled in this case-based cross-sectional study, and their demographic and clinical information, TB genotype clustering statuses, and activity space were collected. Spatial statistics (Global Moran’s I and Getis-Ord Gi* statistics) identified significant hotspots in 152 census tracts, and urban environmental features and tuberculosis patients’ characteristics in these hotspots were assessed. Results Of the enrolled 643 culture-positive tuberculosis patients, 416 (64.2%) were general inhabitants, 42 (6.5%) were foreign-born people, and 184 were homeless people (28.6%). The percentage of overall genotype clustering was 43.7%. Genotype-clustered general inhabitants and homeless people formed significant hotspots around a major railway station, whereas the non-clustered general inhabitants formed no hotspots. This suggested the detected hotspots of activity spaces may reflect ongoing tuberculosis transmission sites and were characterized by smaller residential floor size and a higher proportion of non-working households. Conclusions Activity space-based spatial analysis suggested possible TB transmission sites around the major railway station and it can assist in further

  9. Selective fallopian tube catheterisation in female infertility: clinical results and absorbed radiation dose.

    PubMed

    Nakamura, K; Ishiguchi, T; Maekoshi, H; Ando, Y; Tsuzaka, M; Tamiya, T; Suganuma, N; Ishigaki, T

    1996-01-01

    Clinical results of fluoroscopic fallopian tube catheterisation and absorbed radiation doses during the procedure were evaluated in 30 infertility patients with unilateral or bilateral tubal obstruction documented on hysterosalpingography. The staged technique consisted of contrast injection through an intrauterine catheter with a vacuum cup device, ostial salpingography with the wedged catheter, and selective salpingography with a coaxial microcatheter. Of 45 fallopian tubes examined, 35 (78%) were demonstrated by the procedure, and at least one tube was newly demonstrated in 26 patients (87%). Six of these patients conceived spontaneously in the follow-up period of 1-11 months. Four pregnancies were intrauterine and 2 were ectopic. This technique provided accurate and detailed information in the diagnosis and treatment of tubal obstruction in infertility patients. The absorbed radiation dose to the ovary in the average standardised procedure was estimated to be 0.9 cGy. Further improvement in the X-ray equipment and technique is required to reduce the radiation dose. PMID:8798025

  10. 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.

  11. 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.

  12. The Manihiki Plateau—a key to missing hotspot tracks?

    NASA Astrophysics Data System (ADS)

    Pietsch, R.; Uenzelmann-Neben, G.

    2016-08-01

    A Neogene magmatic reactivation of the Manihiki Plateau, a large igneous province (LIP) in the central Pacific, is studied using seismic reflection data. Igneous diapirs have been identified exclusively within a narrow WNW-ESE striking corridor in the southern High Plateau (HP), which is parallel to the Neogene Pacific Plate motion and overlaps with an extrapolation of the Society Islands Hotspot (SIH) path. The igneous diapirs are characterized by a narrow width (>5 km), penetration of the Neogene sediments, and they become progressively younger towards the East (23-10 Ma). The magmatic source appears to be of small lateral extent, which leads to the conclusion that the diapirs represent Neogene hotspot volcanism within a LIP, and thus may be an older, previously unknown extension of the SIH track (>4.5 Ma). Comparing hotspot volcanism within oceanic and continental lithosphere, we further conclude that hotspot volcanism within LIP crust has similarities to tectonically faulted continental crust.

  13. 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.

  14. 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

  15. Anisotropic radiative transfer problem in optically thick, strongly magnetized plasma: A comparison of results

    SciTech Connect

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

    1985-04-01

    Recently developed methods for solving the coherent radiative transferproblem in a strongly magnetized plasma are compared and analyzed for the caseof a semi-infinite, homogeneous plasma with the magnetic field perpendicular to the surface. The work of Meszaros and Bonazzola is shown to contain some errors. The accuracy of numerical methods proposed by Silant'ev and Nagel is investigated for various plasma parameters and photon energies. The coupled diffusion approximation developed by Nagel and Kaminker et al. appears to give quite satisfactory results and seems to be more efficient in many cases than direct numerical methods.

  16. Investigating Avian Influenza Infection Hotspots in Old-World Shorebirds

    PubMed Central

    Gaidet, Nicolas; Ould El Mamy, Ahmed B.; Cappelle, Julien; Caron, Alexandre; Cumming, Graeme S.; Grosbois, Vladimir; Gil, Patricia; Hammoumi, Saliha; de Almeida, Renata Servan; Fereidouni, Sasan R.; Cattoli, Giovanni; Abolnik, Celia; Mundava, Josphine; Fofana, Bouba; Ndlovu, Mduduzi; Diawara, Yelli; Hurtado, Renata; Newman, Scott H.; Dodman, Tim; Balança, Gilles

    2012-01-01

    Heterogeneity in the transmission rates of pathogens across hosts or environments may produce disease hotspots, which are defined as specific sites, times or species associations in which the infection rate is consistently elevated. Hotspots for avian influenza virus (AIV) in wild birds are largely unstudied and poorly understood. A striking feature is the existence of a unique but consistent AIV hotspot in shorebirds (Charadriiformes) associated with a single species at a specific location and time (ruddy turnstone Arenaria interpres at Delaware Bay, USA, in May). This unique case, though a valuable reference, limits our capacity to explore and understand the general properties of AIV hotspots in shorebirds. Unfortunately, relatively few shorebirds have been sampled outside Delaware Bay and they belong to only a few shorebird families; there also has been a lack of consistent oropharyngeal sampling as a complement to cloacal sampling. In this study we looked for AIV hotspots associated with other shorebird species and/or with some of the larger congregation sites of shorebirds in the old world. We assembled and analysed a regionally extensive dataset of AIV prevalence from 69 shorebird species sampled in 25 countries across Africa and Western Eurasia. Despite this diverse and extensive coverage we did not detect any new shorebird AIV hotspots. Neither large shorebird congregation sites nor the ruddy turnstone were consistently associated with AIV hotspots. We did, however, find a low but widespread circulation of AIV in shorebirds that contrast with the absence of AIV previously reported in shorebirds in Europe. A very high AIV antibody prevalence coupled to a low infection rate was found in both first-year and adult birds of two migratory sandpiper species, suggesting the potential existence of an AIV hotspot along their migratory flyway that is yet to be discovered. PMID:23029383

  17. 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].

  18. Upper mantle structure of shear-waves velocities and stratification of anisotropy in the Afar Hotspot region

    NASA Astrophysics Data System (ADS)

    Sicilia, D.; Montagner, J.-P.; Cara, M.; Stutzmann, E.; Debayle, E.; Lépine, J.-C.; Lévêque, J.-J.; Beucler, E.; Sebai, A.; Roult, G.; Ayele, A.; Sholan, J. M.

    2008-12-01

    The Afar area is one of the biggest continental hotspots active since about 30 Ma. It may be the surface expression of a mantle "plume" related to the African Superswell. Central Africa is also characterized by extensive intraplate volcanism. Around the same time (30 Ma), volcanic activity re-started in several regions of the African plate and hotspots such as Darfur, Tibesti, Hoggar and Mount Cameroon, characterized by a significant though modest volcanic production. The interactions of mantle upwelling with asthenosphere, lithosphere and crust remain unclear and seismic anisotropy might help in investigating these complex interactions. We used data from the global seismological permanent FDSN networks (GEOSCOPE, IRIS, MedNet, GEO- FON, etc.), from the temporary PASSCAL experiments in Tanzania and Saudi Arabia and a French deployment of 5 portable broadband stations surrounding the Afar Hotspot. A classical two-step tomographic inversion from surface waves performed in the Horn of Africa with selected Rayleigh wave and Love wave seismograms leads to a 3D-model of both S V velocities and azimuthal anisotropy, as well as radial SH/ SV anisotropy, with a lateral resolution of 500 km. The region is characterized by low shear-wave velocities beneath the Afar Hotspot, the Red Sea, the Gulf of Aden and East of the Tanzania Craton to 400 km depth. High velocities are present in the Eastern Arabia and the Tanzania Craton. The results of this study enable us to rule out a possible feeding of the Central Africa hotspots from the "Afar plume" above 150-200 km. The azimuthal anisotropy displays a complex pattern near the Afar Hotspot. Radial anisotropy, although poorly resolved laterally, exhibits S H slower than S V waves down to about 150 km depth, and a reverse pattern below. Both azimuthal and radial anisotropies show a stratification of anisotropy at depth, corresponding to different physical processes. These results suggest that the Afar hotspot has a different and

  19. 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.).

  20. 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.

  1. Origin of ΔNeff as a result of an interaction between dark radiation and dark matter

    NASA Astrophysics Data System (ADS)

    Eggers Bjaelde, Ole; Das, Subinoy; Moss, Adam

    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.

  2. The Impact of Hotspot-Targeted Interventions on Malaria Transmission in Rachuonyo South District in the Western Kenyan Highlands: A Cluster-Randomized Controlled Trial

    PubMed Central

    Bradley, John; Knight, Philip; Stone, William; Osoti, Victor; Makori, Euniah; Owaga, Chrispin; Odongo, Wycliffe; China, Pauline; Shagari, Shehu; Doumbo, Ogobara K.; Sauerwein, Robert W.; Kariuki, Simon; Drakeley, Chris; Stevenson, Jennifer; Cox, Jonathan

    2016-01-01

    Background Malaria transmission is highly heterogeneous, generating malaria hotspots that can fuel malaria transmission across a wider area. Targeting hotspots may represent an efficacious strategy for reducing malaria transmission. We determined the impact of interventions targeted to serologically defined malaria hotspots on malaria transmission both inside hotspots and in surrounding communities. Methods and Findings Twenty-seven serologically defined malaria hotspots were detected in a survey conducted from 24 June to 31 July 2011 that included 17,503 individuals from 3,213 compounds in a 100-km2 area in Rachuonyo South District, Kenya. In a cluster-randomized trial from 22 March to 15 April 2012, we randomly allocated five clusters to hotspot-targeted interventions with larviciding, distribution of long-lasting insecticide-treated nets, indoor residual spraying, and focal mass drug administration (2,082 individuals in 432 compounds); five control clusters received malaria control following Kenyan national policy (2,468 individuals in 512 compounds). Our primary outcome measure was parasite prevalence in evaluation zones up to 500 m outside hotspots, determined by nested PCR (nPCR) at baseline and 8 wk (16 June–6 July 2012) and 16 wk (21 August–10 September 2012) post-intervention by technicians blinded to the intervention arm. Secondary outcome measures were parasite prevalence inside hotpots, parasite prevalence in the evaluation zone as a function of distance from the hotspot boundary, Anopheles mosquito density, mosquito breeding site productivity, malaria incidence by passive case detection, and the safety and acceptability of the interventions. Intervention coverage exceeded 87% for all interventions. Hotspot-targeted interventions did not result in a change in nPCR parasite prevalence outside hotspot boundaries (p ≥ 0.187). We observed an average reduction in nPCR parasite prevalence of 10.2% (95% CI −1.3 to 21.7%) inside hotspots 8 wk post

  3. A measurement concept for hot-spot BRDFs from space

    SciTech Connect

    Gerstl, S.A.W.

    1996-09-01

    Several concepts for canopy hot-spot measurements from space have been investigated. The most promising involves active illumination and bistatic detection that would allow hot-spot angular distribution (BRDF) measurements from space in a search-light mode. The concept includes a pointable illumination source, such as a laser operating at an atmospheric window wavelength, coupled with a number of high spatial-resolution detectors that are clustered around the illumination source in space, receiving photons nearly coaxial with the reto-reflection direction. Microwave control and command among the satellite cluster would allow orienting the direction of the laser beam as well as the focusing detectors simultaneously so that the coupled system can function like a search light with almost unlimited pointing capabilities. The concept is called the Hot-Spot Search-Light (HSSL) satellite. A nominal satellite altitude of 600 km will allow hot-spot BRDF measurements out to about 18 degrees phase angle. The distributed are taking radiometric measurements of the intensity wings of the hot-spot angular distribution without the need for complex imaging detectors. The system can be operated at night for increased signal-to-noise ratio. This way the hot-spot angular signatures can be quantified and parameterized in sufficient detail to extract the biophysical information content of plant architectures.

  4. Comparative analysis of somatic copy-number alterations across different human cancer types reveals two distinct classes of breakpoint hotspots

    PubMed Central

    Li, Yudong; Zhang, Li; Ball, Robyn L.; Liang, Xinle; Li, Jianrong; Lin, Zhenguo; Liang, Han

    2012-01-01

    Somatic copy-number alterations (SCNAs) play a crucial role in the development of human cancer. However, it is not well understood what evolutionary mechanisms contribute to the global patterns of SCNAs in cancer genomes. Taking advantage of data recently available through The Cancer Genome Atlas, we performed a systematic analysis on genome-wide SCNA breakpoint data for eight cancer types. First, we observed a high degree of overall similarity among the SCNA breakpoint landscapes of different cancer types. Then, we compiled 19 genomic features and evaluated their effects on the observed SCNA patterns. We found that evolutionary indel and substitution rates between species (i.e. humans and chimpanzees) consistently show the strongest correlations with breakpoint frequency among all the surveyed features; whereas the effects of some features are quite cancer-type dependent. Focusing on SCNA breakpoint hotspots, we found that cancer-type-specific breakpoint hotspots and common hotspots show distinct patterns. Cancer-type-specific hotspots are enriched with known cancer genes but are poorly predicted from genomic features; whereas common hotspots show the opposite patterns. This contrast suggests that explaining high-frequency SCNAs in cancer may require different evolutionary models: positive selection driven by cancer genes, and non-adaptive evolution related to an intrinsically unstable genomic context. Our results not only present a systematic view of the effects of genetic factors on genome-wide SCNA patterns, but also provide deep insights into the evolutionary process of SCNAs in cancer. PMID:22899649

  5. 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.

  6. 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.

  7. 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

  8. Light Penetration in Seawater Polluted by Dispersed Oil: Results of Radiative Transfer Modelling

    NASA Astrophysics Data System (ADS)

    Haule, K.; Darecki, M.; Toczek, H.

    2015-11-01

    The downwelling light in seawater is shaped by natural seawater constituents as well as by some external substances which can occur locally and temporally. In this study we focused on dispersed oil droplets which can be found in seawater after an oil spill or in the consequence of intensive shipping, oil extraction and transportation. We applied our modified radiative transfer model based on Monte Carlo code to evaluate the magnitude of potential influence of dispersed oil droplets on the downwelling irradiance and the depth of the euphotic zone. Our model was validated on the basis of in situ measurements for natural (unpolluted) seawater in the Southern Baltic Sea, resulting in less than 5% uncertainty. The optical properties of dispersed Petrobaltic crude oil were calculated on the basis of Mie theory and involved into radiative transfer model. We found that the changes in downwelling light caused by dispersed oil depend on several factors such as oil droplet concentration, size distribution, and the penetration depth (i.e. vertical range of oil droplets occurrence below sea surface). Petrobaltic oil droplets of submicron sizes and penetration depth of 5 m showed a potentially detectable reduction in the depth of the euphotic zone of 5.5% at the concentration of only 10 ppb. Micrometer-sized droplets needed 10 times higher concentration to give a similar effect. Our radiative transfer model provided data to analyse and discuss the influence of each factor separately. This study contributes to the understanding of the change in visible light penetration in seawater affected by dispersed oil.

  9. [The radiation environment in the Russian Federation according to the results of radiohygienic certification].

    PubMed

    Onishchenko, G G

    2009-01-01

    Ensuring nuclear and radiation safety in the use of atomic energy is one of the most important constituents of the Russian Federation's security, which is laid down in the "Foundations of Public Policy in the nuclear and radiation safety of the Russian Federation till 2010 and Further Prospects". The radiation safety in an area is determined by not only the number of radiation objects in it, the grade of their potential radiation hazard, their maintenance, the nature of use, but also by the measures ensuring radiation safety and preventing possible radiation accidents, and the readiness for liquidation of their consequences, and the effective supervision of whether the requirements are carried out. To assure constant and effective control over radiation safety, a uniform system for the information provision of radiation safety has been developed and introduced in the Russian Federation since 1998, which includes radiohygienic certification and the uniform state system for monitoring and considering the radiation doses exposed by the residents of Russia. The 2007 radiohygienic certification covered more than 16000 organizations dealing with the sources of ionizing irradiations. A total of 202.7 million medical diagnostic radiological procedures were performed in Russia in 2007. It should be noted that the dose of medical irradiation is reduced. In general, the radiation environment in the Russian Federation is satisfactory, but in a number of its regions there are reasonably serious problems associated with the population's radiation safety. PMID:19645102

  10. Radiation environment study of near space in China area

    NASA Astrophysics Data System (ADS)

    Fan, Dongdong; Chen, Xingfeng; Li, Zhengqiang; Mei, Xiaodong

    2015-10-01

    Aerospace activity becomes research hotspot for worldwide aviation big countries. Solar radiation study is the prerequisite for aerospace activity to carry out, but lack of observation in near space layer becomes the barrier. Based on reanalysis data, input key parameters are determined and simulation experiments are tried separately to simulate downward solar radiation and ultraviolet radiation transfer process of near space in China area. Results show that atmospheric influence on the solar radiation and ultraviolet radiation transfer process has regional characteristic. As key factors such as ozone are affected by atmospheric action both on its density, horizontal and vertical distribution, meteorological data of stratosphere needs to been considered and near space in China area is divided by its activity feature. Simulated results show that solar and ultraviolet radiation is time, latitude and ozone density-variant and has complicated variation characteristics.

  11. Plume and plate controlled hotspot trails in the South Atlantic

    NASA Astrophysics Data System (ADS)

    O'Connor, John; Jokat, Wilfried; le Roex, Anton; Class, Cornelia; Wijbrans, Jan; Keßling, Stefanie; Kuiper, Klaudia; Nebel, Oliver

    2013-04-01

    Discovering if hotspots observed on the Earth's surface are explained by underlying plumes rising from the deep mantle or by shallow plate-driven processes continues to be an essential goal in Earth Science. Key evidence underpinning the mantle plume concept is the existence of age-progressive volcanic trails recording past plate motion relative to surface hotspots and their causal plumes. Using the icebreaker RV Polarstern, we sampled scattered hotspot trails on the 2,000 km-wide southeast Atlantic hotspot swell, which projects down to one of the Earth's two largest and deepest regions of slower-than-average seismic wave speed - the Africa Low Shear Wave Velocity Province - caused by a massive thermo-chemical 'pile' on the core-mantle boundary. We showed recently using Ar/Ar isotopic ages - and crustal structure and seafloor ages - that these hotspot trails are age progressive and formed synchronously across the swell, consistent with African plate motion over plumes rising from the stable edge of a Low Shear Wave Velocity Province (LLSVP) (O'Connor et al., 2012). We showed furthermore that hotspot trails formed initially only at spreading boundaries at the outer edges of the swell until roughly 44 million years ago, when they started forming across the swell, far from spreading boundaries in lithosphere that was sufficiently weak (young) for plume melts to reach the surface. We concluded that if plume melts formed synchronous age progressive hotspot trails whenever they could penetrate the lithosphere, then hotspot trails in the South Atlantic are controlled by the interplay between deep plumes and the shallow motion and structure of the African plate. If the distribution of hotspot trails reflects where plume melts could or could not penetrate the continental or oceanic lithosphere then plumes could have been active for significantly longer than indicated by their volcanic chains. This provides a mechanism for extended late stage interplay between deep mantle

  12. Reduced exposure to microwave radiation by rats: frequency specific effects

    SciTech Connect

    D'Andrea, J.A.; DeWitt, J.R.; Portuguez, L.M.; Gandhi, O.P.

    1988-01-01

    Previous research has shown that SAR hotspots are induced within the laboratory rat and that the resulting thermal hotspots are not entirely dissipated by bloodflow. Two experiments were conducted to determine if hotspot formation in the body and tail of the rat, which is radiation frequency specific, would have behavioral consequences. In the first experiment rats were placed in a plexiglas cage one side of which, when occupied by the rat, commenced microwave radiation exposure; occupancy of the other side terminated exposure. Groups of rats were tested during a baseline period to determine the naturally preferred side of the cage. Subsequent exposure to 360-MHz, 700-MHz or 2450-MHz microwave radiation was made contingent on preferred-side occupancy. A significant reduction in occupancy of the preferred side of the cage, and hence, microwaves subsequently occurred. Reduced exposure to 360-MHz and 2450-MHz microwaves at 1, 2, 6 and 10 W/kg were significantly different from 700-MHz microwaves. In the second experiment semichronic exposures revealed the threshold for reduced exposure of 2450-MHz microwaves to be located between whole-body SAR's of 2.1 and 2.8 W/kg.

  13. 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

  14. The Hawaiian Archipelago: a microbial diversity hotspot.

    PubMed

    Donachie, S P; Hou, S; Lee, K S; Riley, C W; Pikina, A; Belisle, C; Kempe, S; Gregory, T S; Bossuyt, A; Boerema, J; Liu, J; Freitas, T A; Malahoff, A; Alam, M

    2004-11-01

    The Hawaiian Archipelago is a "biodiversity hotspot" where significant endemism among eukaryotes has evolved through geographic isolation and local topography. To address the absence of corresponding region-wide data on Hawaii's microbiota, we compiled the first 16S SSU rDNA clone libraries and cultivated bacteria from five Hawaiian lakes, an anchialine pool, and the Lō'ihi submarine volcano. These sites offer diverse niches over approximately 5000 m elevation and approximately 1150 nautical miles. Each site hosted a distinct prokaryotic community dominated by Bacteria. Cloned sequences fell into 158 groups from 18 Bacteria phyla, while seven were unassigned and two belonged in the Euryarchaeota. Only seven operational taxonomic units (each OTU comprised sequences that shared > or =97% sequence identity) occurred in more than one site. Pure bacterial cultures from all sites fell into 155 groups (each group comprised pure cultures that shared > or =97% 16S SSU rDNA sequence identity) from 10 Bacteria phyla; 15 Proteobacteria and Firmicutes were cultivated from more than one site. One hundred OTUs (60%) and 52 (33.3%) cultures shared <97% 16S SSU rDNA sequence identity with published sequences. Community structure reflected habitat chemistry; most delta-Proteobacteria occurred in anoxic and sulfidic waters of one lake, while beta-Proteobacteria were cultivated exclusively from fresh or brackish waters. Novel sequences that affiliate with an Antarctic-specific clade of Deinococci, and Candidate Divisions TM7 and BRC1, extend the geographic ranges of these phyla. Globally and locally remote, as well as physically and chemically diverse, Hawaiian aquatic habitats provide unique niches for the evolution of novel communities and microorganisms. PMID:15696384

  15. Hybridization Hotspots at Bat Swarming Sites

    PubMed Central

    Bogdanowicz, Wiesław; Piksa, Krzysztof; Tereba, Anna

    2012-01-01

    During late summer and early autumn in temperate zones of the Northern Hemisphere, thousands of bats gather at caves, mainly for the purpose of mating. We demonstrated that this swarming behavior most probably leads not only to breeding among bats of the same species but also interbreeding between different species. Using 14 nuclear microsatellites and three different methods (the Bayesian assignment approaches of STRUCTURE and NEWHYBRIDS and a principal coordinate analysis of pairwise genetic distances), we analyzed 375 individuals belonging to three species of whiskered bats (genus Myotis) at swarming sites across their sympatric range in southern Poland. The overall hybridization rate varied from 3.2 to 7.2%. At the species level, depending on the method used, these values ranged from 2.1–4.6% in M. mystacinus and 3.0–3.7% in M. brandtii to 6.5–30.4% in M. alcathoe. Hybrids occurred in about half of the caves we studied. In all three species, the sex ratio of hybrids was biased towards males but the observed differences did not differ statistically from those noted at the population level. In our opinion, factors leading to the formation of these admixed individuals and their relatively high frequency are: i) swarming behaviour at swarming sites, where high numbers of bats belonging to several species meet; ii) male-biased sex ratio during the swarming period; iii) the fact that all these bats are generally polygynous. The highly different population sizes of different species at swarming sites may also play some role. Swarming sites may represent unique hybrid hotspots, which, as there are at least 2,000 caves in the Polish Carpathians alone, may occur on a massive scale not previously observed for any group of mammal species in the wild. Evidently, these sites should be treated as focal points for the conservation of biodiversity and evolutionary processes. PMID:23300912

  16. Results of radiation tests performed on the ISOCAM infrared detector array

    NASA Astrophysics Data System (ADS)

    Agnese, P.; Engelmann, J. J.; Mottier, P.

    1991-08-01

    Extensive radiation tests have been performed on the long-wavelength IR detector array for the ISOCAM camera, to be launched on the European ISO satellite. Transient and memory effects, induced by gamma-rays, protons, and heavy ions have been investigated. Each time a pixel is traversed by a particle, an ionization pulse is generated. The results of different deglitching techniques have been compared. Among them, the half Gauss method seems to be the best. In addition to the transient effect, a memory effect is induced by the radiation: an increase of the photoconductive gain is observed. For 2 rad, the raise in responsivity is about 60 percent. The relaxation time is the order of 1 h. The relativistic Fe ions present in cosmic rays have been simulated by Argon ions of 70 MeV/nucleon energy. These very heavily ionizing particles induce a large responsivity change, not only in the pixels directly hit by the particles, but also in their neighbors.

  17. Saturnian trapped radiation and its absorption by satellites and rings - The first results from Pioneer 11

    NASA Technical Reports Server (NTRS)

    Simpson, J. A.; Bastian, T. S.; Chenette, D. L.; Lentz, G. A.; Mckibben, R. B.; Pyle, K. R.; Tuzzolino, A. J.

    1980-01-01

    Preliminary results from Pioneer 11 concerning the acceleration and trapping of charged particles in the magnetic field of Saturn are reported. The identification and measurement of the intensities and spectra of charged particle species was performed by an experiment including four charged particle sensor systems, within 20 Saturn radii of the planet. Increases in the intensity of 0.5- to 1.8-MeV protons within 15 Saturn radii indicate the trapping and acceleration of particles in the dipole field region, while a decrease in proton intensity between seven and four Saturn radii is attributed to absorption by Dione and Enceladus and possibly ring material as well. Proton and electron intensity distributions are found to be axially symmetric within four Saturn radii, indicating a centered dipole aligned with the planetary rotation axis. Trapped radiation absorption at the orbit of Mimas is analyzed to obtain an upper limit of 4 x 10 to the -8th Saturn radii-squared/sec to the inward diffusion coefficient; an absorption-like feature observed at L = 2.5 is attributed to a previously unidentified satellite of diameter less than 200 km and semimajor axis 2.51 Saturn radii. Radiation absorption by the newly discovered F ring was also observed, however beneath the A, B and C rings a low flux of high-energy electrons was detected.

  18. Investigation of Current Hotspots on an Ion-Selective Membrane Subject to Chaotic Electroconvection

    NASA Astrophysics Data System (ADS)

    Druzgalski, Clara

    2015-11-01

    We have performed a 3D direct numerical simulation (DNS) of chaotic ion transport associated with electroconvective instability near an ion-selective membrane. Data from the 3D DNS demonstrate that the chaotic fluid motion substantially influences the transport of ions and causes instantaneous hotspots of high current density on the surface. We present a comprehensive statistical analysis of surface current density, including probability density functions (PDFs) and joint-PDFs with other interfacial measures involving flow, conductivity and electric fields. These results provide new insights into the mechanism and characterization of current hotspots. Our results are relevant to industrial applications involving ion-selective interfaces such as electrodialysis for water purification, and emerging microfluidic devices that use ion-selective components for separation processes.

  19. Hot-spot tectonics on Io

    NASA Technical Reports Server (NTRS)

    Mcewen, A. S.

    1985-01-01

    The thesis is that extensional tectonics and low-angle detachment faults probably occur on Io in association with the hot spots. These processes may occur on a much shorter timescale on Ion than on Earth, so that Io could be a natural laboratory for the study of thermotectonics. Furthermore, studies of heat and detachment in crustal extension on Earth and the other terresrial planets (especially Venus and Mars) may provide analogs to processes on Io. The geology of Io is dominated by volcanism and hot spots, most likely the result of tidal heating. Hot spots cover 1 to 2% of Io's surface, radiating at temperatures typically from 200 to 400 K, and occasionally up to 700K. Heat loss from the largest hot spots on Io, such as Loki Patera, is about 300 times the heat loss from Yellowstone, so a tremendous quantity of energy is available for volcanic and tectonic work. Active volcanism on Io results in a resurfacing rate as high as 10 cm per year, yet many structural features are apparent on the surface. Therefore, the tectonics must be highly active.

  20. 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

  1. 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.

  2. A Double Hotspot Model for the Origin of Line Islands Ridge

    NASA Astrophysics Data System (ADS)

    Pockalny, R. A.; Barth, G. A.; Wertman, C.

    2015-12-01

    The origin of the various seamount chains in the central Pacific is often difficult to reconstruct due to the number of potential volcanic sources and the criss-crossing patterns associated with plate motion history. One particularly difficult seamount chain to reconstruct is the Line Islands Ridge and the possibly-related Mid-Pacific Mountains and Tuamotu Chain. While the general geographic and age-progressive trends of these features resemble the predicted pattern for Pacific plate motion over the past 120 to 130 My, the relative ages of volcanism along the Line Islands Ridge are not consistent with a conventional hotspot model. To explore potential models of the origin of the Line Islands Ridge, we use GPlates software in conjunction with published seamount dates and known hotspot locations to constrain tectonic reconstructions. Our primary results suggest the Line Islands Ridge was formed by at least two different volcanic sources. The initial source formed the southern section of the Line Island Ridge (4˚N to 1˚S) around 95 to 83 Ma and corresponds to the present-day Crough hotspot. The hotspot also likely generated the linear Boudeuse Ridge (a.k.a. Southern Line Islands) volcanic chain (5˚S to 13˚S) from about 70 to 50 Ma. The second volcanic source, which we call the Larson Hotspot in memory of Roger Larson, formed the northern section of the Line Islands Ridge (7˚N to 4˚N) around 77 to 64 Ma and corresponds to a new "hotspot" region centered on 17˚S and 125˚W near the eastern extension of the Pukapuka Ridge. This source may also account for the formation of the Mid-Pacific Mountains (130 to 105 Ma), the Necker Ridge (105 to 90 Ma), and the later volcanism on the southern section of the Line Island Ridge (65 to 55 Ma). This volcanic source also roughly coincides with the Pukapuka Ridge and more recent volcanism along the same trend, but closer to the East Pacific Rise.

  3. Hotspots on Io During the Ganymede 2 Encounter

    NASA Technical Reports Server (NTRS)

    1996-01-01

    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 6 September 1996. This image shows, on the right, Io as seen by NIMS, centered on 150 W longitude. The image on the left shows the same view point from Voyager data (from the encounters in 1979 and 1980). The NIMS image can be compared to the NIMS hotspot image from the G1 orbit (June 1996) to monitor changes on Io. The most dramatic feature of the G2 image is the hotspot at Malik Patera. Preliminary analysis of the data yields a temperature of at least 1000 K (727 C) for this hotspot, an increase of more than 300 K from the G1 encounter. In the overlap area of the G1 and G2 images all the hotspots seen during the G1 encounter are also seen in the G2 image. Other hotspots were seen, including one at the Pele plume origin site. This image is at the 4 micron band to best view the Malik hotspot. Most of the other hotspots are best seen at longer wavelengths. NIMS is continuing to observe Io to monitor volcanic activity throughout the Galileo mission.

    The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov.

  4. Prediction and measurement results of radiation damage to CMOS devices on board spacecraft

    NASA Technical Reports Server (NTRS)

    Stassinopoulos, E. G.; Danchenko, V.; Cliff, R. A.; Sing, M.; Brucker, G. J.; Ohanian, R. S.

    1977-01-01

    Final results from the CMOS Radiation Effects Measurement (CREM) experiment flown on Explorer 55 are presented and discussed, based on about 15 months of observations and measurements. Conclusions are given relating to long-range annealing, effects of operating temperature on semiconductor performance in space, biased and unbiased P-MOS device degradation, unbiased n-channel device performance, changes in device transconductance, and the difference in ionization efficiency between Co-60 gamma rays and 1-Mev Van de Graaff electrons. The performance of devices in a heavily shielded electronic subsystem box within the spacecraft is evaluated and compared. Environment models and computational methods and their impact on device-degradation estimates are being reviewed to determine whether they permit cost-effective design of spacecraft.

  5. Code System for Calculating Radiation Exposure Resulting from Accidental Radioactive Releases to the Hydrosphere.

    Energy Science and Technology Software Center (ESTSC)

    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) tomore » 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.« less

  6. 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.

  7. New Results from Space and Field Observations on the Aerosol Direct and Indirect Radiative Forcing

    NASA Technical Reports Server (NTRS)

    Kaufman, Yoram J.; Remer, Lorraine; Tanre, Didier; Boucher, Olivier; Chin, Mian; Dubovik, Oleg; Holben, Brent

    2002-01-01

    New space observations from the MODIS instrument on board the Terra satellite and analysis of POLDER data flown on the ADEOS satellite, show in great details the spatial and seasonal variability of the global aerosol system. These spaceborne instruments distinguish fine aerosol from man-made regional pollution and biomass burning from mostly natural coarse dust and sea salt aerosol. E.g. fine regional pollution in and around the Indian sub-continent, Europe and North America; smoke from biomass burning in Southern Africa and Southern America; coarse dust from West Africa and mixed dust pollution and smoke from West and central Africa and East Asia. These regions were also studied extensively in focused field experiments and by the distributed AERONET network. The results generate the first climatologies of the aerosol system, are used to derive the aerosol radiative effects and to estimate the anthropogenic component. The measurements are also used to evaluate each other and constrain aerosol transport models.

  8. 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

  9. 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

  10. 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

  11. Improved detection of coastal acid sulfate soil hotspots through biomonitoring of metal(loid) accumulation in water lilies (Nymphaea capensis).

    PubMed

    Stroud, Jacqueline L; Collins, Richard N

    2014-07-15

    Anthropogenically disturbed coastal acid sulfate soils along the east coast of Australia, and worldwide, periodically result in the discharge of acid waters containing high concentrations of metals. Identifying priority sites (hotspots) within a catchment for acid sulfate soil remediation activities typically involves long-term monitoring of drainwater chemistry, including the capture of data on unpredictable rain-induced groundwater discharge events. To improve upon this monitoring approach, this study investigated using the water lily (Nymphaea capensis) as a biomonitor of drainage waters to identify hotspots in three acid sulfate soil impacted catchments (83 km(2)) in north-eastern New South Wales, Australia. In one catchment where the location of hotspots was known, water lily lamina concentrations of a suite of metal(loid)s were significantly (p<0.05) higher than plants collected from an unpolluted 'reference' drainage channel, thus validating the concept of using this species as a biomonitor. A catchment-scale water lily sampling program undertaken in catchments with unidentified hotspots revealed within catchment variation of plant metal concentrations up to 70-fold. High resolution maps produced from these results, therefore, provided strong evidence for the location of potential hotspots which were confirmed with measurements of drainwater chemistry during rain-induced groundwater discharge events. Median catchment lily accumulation was ca. 160 mg Al kg(-1) and 1,300 mg Fe kg(-1), with hotspots containing up to 6- and 10-fold higher Al and Fe concentrations. These findings suggest that biomonitoring with N. capensis can be an important tool to rapidly identify priority sites for remediation in acid sulfate soil impacted landscapes. PMID:24805963

  12. Investigating spatial and volumetric trends in silicic volcanism along the Yellowstone hotspot track using high-resolution thermomechanical numerical models

    NASA Astrophysics Data System (ADS)

    Colon, D.; Bindeman, I. N.; Gerya, T.

    2015-12-01

    Roughly 2 Ma gaps exist between the Picabo and Heise (from ~8.4 to 6.6Ma) and the Heise and Yellowstone (4.40 to 2.1 Ma) centers along the Yellowstone hotspot track, each of which experienced magmatic activity for several million years. We employ high-resolution magmatic-thermomechanical models of the interaction between a mantle plume and thick continental crust to investigate the causes of the spatial and temporal jumps that occur between these eruptive centers, using a stress implementation of magmatic processes, nonlinear temperature-dependent melting, and progressive depletion the rocks from which magmas are extracted. We investigate two possible mechanisms of these jumps in active centers. First, the spacing between eruptive centers is a function of the longevity of amagma conduit in beneath each eruptive center, which must be abandoned when the crust moves too far away from the center of the hotspot, with the distance traveled by the plate in this time determining the spacing between eruptive centers. Alternatively, the cessation of activity at a given eruptive center is controlled by the formation of geochemically depleted "dead zones" which force any new silicic volcanism to occur in a new area of less depleted crust, with the spacing between centers controlled by the size of these dead zones. By varying the speed of the crust over the hotspot, the thickness and composition of the crust, we can determine the relative importance of these two processes for volcanism along the Yellowstone hotspot track has likely changed over time, with implications for changes in average eruptive volumes and repose times between large eruptions over the last 12 Ma. Early results suggest that heating of the crust causes areas of melt accumulation to move upward with time before resetting to a deeper level as the crust moves over the hotspot, a possible additional source of discrete behavior along the hotspot track. We check our results using existing geochemical constraints.

  13. New strategy toward dioxin risk reduction for local residents surrounding severe dioxin hotspots in Vietnam

    PubMed Central

    Thi Tran, Tuyet-Hanh; Nguyen, Ngoc-Bich; Le, Vu-Anh

    2013-01-01

    Background A public health intervention program with active involvement of local related stakeholders was piloted in the Bien Hoa dioxin hotspot (2007–2009), and then expanded to the Da Nang dioxin hotspot in Vietnam (2009–2011). It aimed to reduce the risk of dioxin exposure of local residents through foods. This article presents the results of the intervention in Da Nang. Methodology To assess the results of this intervention program, pre- and post-intervention knowledge, attitude, and practice (KAP) surveys were implemented in 400 households, randomly selected from four wards surrounding the Da Nang Airbase in 2009 and 2011, respectively. Results After the intervention, the knowledge on the existence of dioxin in food, dioxin exposure pathways, potential high-risk foods, and preventive measures significantly increased (P<0.05). Ninety-eight percent were willing to follow advice on preventing dioxin exposure. Practices to reduce the risk of dioxin exposure also significantly improved (P<0.05). After intervention, 60.4% of households undertook exposure preventive measures, significantly higher than that of the pre-intervention survey (39.6%; χ2=40.15, P<0.001). High-risk foods had quite low rates of daily consumption (from 0 to 2.5%) and were significantly reduced (P<0.05). Conclusions This is seen as an effective intervention strategy toward reducing the risk of human exposure to dioxin at dioxin hotspots. While greater efforts are needed for remediating dioxin-polluted areas inside airbases, there is also evidence to suggest that, during the past four decades, pollution has expanded to the surrounding areas. For this reason, this model should be quickly expanded to the remaining dioxin hotspots in Vietnam to further reduce the exposure risks in other areas. PMID:23791241

  14. 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

  15. Protein interaction hotspot identification using sequence-based frequency-derived features.

    PubMed

    Nguyen, Quang-Thang; Fablet, Ronan; Pastor, Dominique

    2013-11-01

    Finding good descriptors, capable of discriminating hotspot residues from others, is still a challenge in many attempts to understand protein interaction. In this paper, descriptors issued from the analysis of amino acid sequences using digital signal processing (DSP) techniques are shown to be as good as those derived from protein tertiary structure and/or information on the complex. The simulation results show that our descriptors can be used separately to predict hotspots, via a random forest classifier, with an accuracy of 79% and a precision of 75%. They can also be used jointly with features derived from tertiary structures to boost the performance up to an accuracy of 82% and a precision of 80%. PMID:21742567

  16. Characterizing Hot-Spot Dynamics of Direct-Drive Cryogenic Implosions on OMEGA

    NASA Astrophysics Data System (ADS)

    Anderson, K. S.; McKenty, P. W.; Shvydky, A.; Knauer, J. P.; Collins, T. J. B.; Delettrez, J. A.; Keller, D.; Marinak, M. M.

    2015-11-01

    In direct-drive inertial confinement fusion, nonuniformities in laser drive, capsule manufacture, and target positioning lead to non-radial hydrodynamic flow in the hot spot at stagnation. Characterizing such flow in the hot spot requires simulating the entire capsule in three dimensions to remove symmetry boundary conditions, which artificially constrain hot-spot flow. This paper will present results from 3-D simulations of cryogenic implosions on OMEGA using HYDRA. Low-mode asymmetries and their contributions to residual hot-spot kinetic energy will be discussed. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944 and performed under the auspices of LLNL under Contract No. DE-AC52-07NA27344.

  17. Multiphysics Simulations of Hot-Spot Initiation in Shocked Insensitive High-Explosive

    NASA Astrophysics Data System (ADS)

    Najjar, Fady; Howard, W. M.; Fried, L. E.

    2010-11-01

    Solid plastic-bonded high-explosive materials consist of crystals with micron-sized pores embedded. Under mechanical or thermal insults, these voids increase the ease of shock initiation by generating high-temperature regions during their collapse that might lead to ignition. Understanding the mechanisms of hot-spot initiation has significant research interest due to safety, reliability and development of new insensitive munitions. Multi-dimensional high-resolution meso-scale simulations are performed using the multiphysics software, ALE3D, to understand the hot-spot initiation. The Cheetah code is coupled to ALE3D, creating multi-dimensional sparse tables for the HE properties. The reaction rates were obtained from MD Quantum computations. Our current predictions showcase several interesting features regarding hot spot dynamics including the formation of a "secondary" jet. We will discuss the results obtained with hydro-thermo-chemical processes leading to ignition growth for various pore sizes and different shock pressures.

  18. 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.

  19. Implications of salinity pollution hotspots on agricultural production

    NASA Astrophysics Data System (ADS)

    Floerke, Martina; Fink, Julia; Malsy, Marcus; Voelker, Jeanette; Alcamo, Joseph

    2016-04-01

    Salinity pollution can have many negative impacts on water resources used for drinking, irrigation, and industrial purposes. Elevated concentrations of salinity in irrigation water can lead to decreased crop production or crop death and, thus, causing an economic problem. Overall, salinity pollution is a global problem but tends to be more severe in arid and semi-arid regions where the dilution capacity of rivers and lakes is lower and the use of irrigation higher. Particularly in these regions agricultural production is exposed to high salinity of irrigation water as insufficient water quality further reduces the available freshwater resources. According to the FAO, irrigated agriculture contributes about 40 percent of the total food production globally, and therefore, high salinity pollution poses a major concern for food production and food security. We use the WaterGAP3 modeling framework to simulate hydrological, water use, and water quality conditions on a global scale for the time period 1990 to 2010. The modeling framework is applied to simulate total dissolved solids (TDS) loadings and in-stream concentrations from different point and diffuse sources to get an insight on potential environmental impacts as well as risks to agricultural food production. The model was tested and calibrated against observed data from GEMStat and literature sources. Although global in scope, the focus of this study is on developing countries, i.e., in Africa, Asia, and Latin America, as these are most threatened by salinity pollution. Furthermore, insufficient water quality for irrigation and therefore restrictions in irrigation water use are examined, indicating limitations to crop production. Our results show that elevated salinity concentrations in surface waters mainly occur in peak irrigation regions as irrigated agriculture is not only the most relevant water use sector contributing to water abstractions, but also the dominant source of salinity pollution. Additionally

  20. Plumes, Hotspot & Slabs Imaged by Global Adjoint Tomography

    NASA Astrophysics Data System (ADS)

    Bozdag, E.; Lefebvre, M. P.; Lei, W.; Peter, D. B.; Smith, J. A.; Komatitsch, D.; Tromp, J.

    2015-12-01

    We present the "first generation" global adjoint tomography model based on 3D wave simulations, which is the result of 15 conjugate-gradient iterations with confined transverse isotropy to the upper mantle. Our starting model is the 3D mantle and crustal models S362ANI (Kustowski et al. 2008) and Crust2.0 (Bassin et al. 2000), respectively. We take into account the full nonlinearity of wave propagation in numerical simulations including attenuation (both in forward and adjoint simulations), topography/bathymetry, etc., using the GPU version of the SPECFEM3D_GLOBE package. We invert for crust and mantle together without crustal corrections to avoid any bias in mantle structure. We started with an initial selection of 253 global CMT events within the magnitude range 5.8 ≤ Mw ≤ 7.0 with numerical simulations having resolution down to 27 s combining 30-s body and 60-s surface waves. After the 12th iteration we increased the resolution to 17 s, including higher-frequency body waves as well as going down to 45 s in surface-wave measurements. We run 180-min seismograms and assimilate all minor- and major-arc body and surface waves. Our 15th iteration model update shows a tantalisingly enhanced image of the Tahiti plume as well as various other plumes and hotspots, such as Caroline, Galapagos, Yellowstone, Erebus, etc. Furthermore, we see clear improvements in slab resolution along the Hellenic and Japan Arcs, as well as subduction along the East of Scotia Plate, which does not exist in the initial model. Point-spread function tests (Fichtner & Trampert 2011) suggest that we are close to the resolution of continental-scale studies in our global inversions and able to confidently map features, for instance, at the scale of the Yellowstone hotspot. This is a clear consequence of our multi-scale smoothing strategy, in which we define our smoothing operator as a function of the approximate Hessian kernel and smooth our gradients less wherever we have good ray coverage

  1. Dynamically supported geoid highs over hotspots - Observation and theory

    NASA Technical Reports Server (NTRS)

    Richards, Mark A.; Hager, Bradford H.; Sleep, Norman H.

    1988-01-01

    Hotspots are associated with long wavelength geoid highs, an association that is even stronger when the geoid highs associated with subduction zones are removed. These associations are quantified by expanding the hotspot distribution in spherical harmonics and calculating correlation coefficients as a function of harmonic degree. The hotspot distribution spectrum is essentially white, with peaks at degrees 2 and 6. It is correlated positively with the slab residual geoid for degrees 2 to 6, with low seismic velocity in the lower mantle at degree 2, and with low seismic velocity in the upper mantle at degree 6. A variety of fluid mechanical models were tested for hotspots, including lithospheric delamination and hot plumes, by calculating their predicted dynamic geoid responses and comparing them to the observations. These models include the effects of temperature dependent rheology. The preferred hotspot model, based on observations of the geoid and seismic tomography, has plumes preferentially occurring in regions of large scale background temperature highs in a mantle with substantial viscosity increase with depth, although other models are possible.

  2. Dynamically supported geoid highs over hotspots: Observation and theory

    NASA Technical Reports Server (NTRS)

    Richards, M. A.; Hager, B. H.; Sleep, N. H.

    1986-01-01

    Hotspots are associated with long wavelength geoid highs, an association that is even stronger when the geoid highs associated with subduction zones are removed. These associations are quantified by expanding the hotspot distribution in spherical harmonics and calculating correlation coefficients as a function of harmonic degree. The hotspot distribution spectrum is essentially white, with peaks at degrees 2 and 6. It is correlated positively with the slab residual geoid for degrees 2 to 6, with low seismic velocity in the lower mantle at degree 2, and with low seismic velocity in the upper mantle at degree 6. A variety of fluid mechanical models were tested for hotspots, including lithospheric delamination and hot plumes, by calculating their predicted dynamic geoid responses and comparing them to the observations. These models include the effects of temperature dependent rheology. The preferred hotspot model, based on observations of the geoid and seismic tomography, has plumes preferentially occurring in regions of large scale background temperature highs in a mantle with substantial viscosity increase with depth, although other models are possible.

  3. Identifying Interactions that Determine Fragment Binding at Protein Hotspots.

    PubMed

    Radoux, Chris J; Olsson, Tjelvar S G; Pitt, Will R; Groom, Colin R; Blundell, Tom L

    2016-05-12

    Locating a ligand-binding site is an important first step in structure-guided drug discovery, but current methods do little to suggest which interactions within a pocket are the most important for binding. Here we illustrate a method that samples atomic hotspots with simple molecular probes to produce fragment hotspot maps. These maps specifically highlight fragment-binding sites and their corresponding pharmacophores. For ligand-bound structures, they provide an intuitive visual guide within the binding site, directing medicinal chemists where to grow the molecule and alerting them to suboptimal interactions within the original hit. The fragment hotspot map calculation is validated using experimental binding positions of 21 fragments and subsequent lead molecules. The ligands are found in high scoring areas of the fragment hotspot maps, with fragment atoms having a median percentage rank of 97%. Protein kinase B and pantothenate synthetase are examined in detail. In each case, the fragment hotspot maps are able to rationalize a Free-Wilson analysis of SAR data from a fragment-based drug design project. PMID:27043011

  4. The proximity of hotspots to convergent and divergent plate boundaries

    NASA Technical Reports Server (NTRS)

    Weinstein, Stuart A.; Olson, Peter L.

    1989-01-01

    An analysis of four different hotspot distributions, ranging from Morgan's (1972) original list of 19 to Vogt's (1981) list of 117 reveals that the hotspots are preferentially located near divergent plate boundaries. The probability of this proximity occurring by chance alone is quite remote, less than 0.01 for all four hotspot distributions. The same analysis also reveals that the hotspots are preferentially excluded from regions near convergent plate boundaries. The probability of this exclusion occurring by chance alone is 0.1 or less for three out of the four distributions examined. We interpret this behavior as being a consequence of the effects of large scale convective circulation on ascending mantle plumes. Mantle thermal plumes, the most probable source of hotspots, arise from instabilities in a basal thermal boundary layer. Plumes are suppressed from regions beneath convergent boundaries by descending flow and are entrained into the upwelling flow beneath spreading centers. Plate-scale convective circulation driven by subduction may also advect mantle thermal plumes toward spreading centers.

  5. Exploring spatial patterns and hotspots of diarrhea in Chiang Mai, Thailand

    PubMed Central

    Chaikaew, Nakarin; Tripathi, Nitin K; Souris, Marc

    2009-01-01

    Background Diarrhea is a major public health problem in Thailand. The Ministry of Public Health, Thailand, has been trying to monitor and control this disease for many years. The methodology and the results from this study could be useful for public health officers to develop a system to monitor and prevent diarrhea outbreaks. Methods The objective of this study was to analyse the epidemic outbreak patterns of diarrhea in Chiang Mai province, Northern Thailand, in terms of their geographical distributions and hotspot identification. The data of patients with diarrhea at village level and the 2001–2006 population censuses were collected to achieve the objective. Spatial analysis, using geographic information systems (GIS) and other methods, was used to uncover the hidden phenomena from the data. In the data analysis section, spatial statistics such as quadrant analysis (QA), nearest neighbour analysis (NNA), and spatial autocorrelation analysis (SAA), were used to identify the spatial patterns of diarrhea in Chiang Mai province. In addition, local indicators of spatial association (LISA) and kernel density (KD) estimation were used to detect diarrhea hotspots using data at village level. Results The hotspot maps produced by the LISA and KD techniques showed spatial trend patterns of diarrhea diffusion. Villages in the middle and northern regions revealed higher incidences. Also, the spatial patterns of diarrhea during the years 2001 and 2006 were found to represent spatially clustered patterns, both at global and local scales. Conclusion Spatial analysis methods in GIS revealed the spatial patterns and hotspots of diarrhea in Chiang Mai province from the year 2001 to 2006. To implement specific and geographically appropriate public health risk-reduction programs, the use of such spatial analysis tools may become an integral component in the epidemiologic description, analysis, and risk assessment of diarrhea. PMID:19552822

  6. Constraining nitrogen cycling hotspots in contaminated aquifers

    NASA Astrophysics Data System (ADS)

    Wells, Naomi; Knoeller, Kay

    2014-05-01

    Accurate assessments of the fate of inorganic nitrogen (N) in groundwater are needed in order to mitigate the threat that ammonium (NH4+) and nitrate (NO3-) pose to water quality and the long-term health of down-gradient ecosystems. However, such assessments are currently limited by difficulties in measuring the biological attenuation (via either denitrification or anaerobic ammonia oxidation (anammox)) of these reactive species in-situ. Based on the knowledge that both of these processes can create unique fractionation patterns in the residual N pools, the objective of this research was to build a template for identifying and quantifying N removal hotspots within complex aquifers using isofluxes. The variations in concentration and isotopic abundance of multiple dissolved inorganic N species (δ15N of NH4+, and δ15N and δ18O of NO2- and NO3-) were measured in 100 wells across two contaminated megasites in Western Europe. The sampling locations were selected span the NH4+ (the dominant N form in both sites) concentration gradient (0 to 900 mg NH4+-N l-1) over depth and distance, which coincided with gradients in co-contaminants BTEX and sulphate of 0 to 5 mg l-1 4 to 11000 mg l-1, respectively. Although NO2- is a key component of both anaerobic and aerobic ammonium oxidation, it is rarely detected in groundwater. Yet, by analysing for it on-site, we found that NO2- concentrations reached up to 0.7 mg NO2-N l-1 and had a highly sensitive isotopic composition (mean of -5 ±23o (δ15N) and +11 ±12o (δ18O)). The largest NO2- concentrations coincided with those of NH4+ levels, meaning that attenuation fluxes could be partitioned between anammox and denitrification using simple isotope mass balance calculations based on Rayleigh type isotope fractionation and established nitrate (δ15N and δ18O) isotope dynamics during denitrification. The constraints on N attenuation within these complex hydrological and chemical setting created by overlaying isoflux maps for each

  7. Biogeochemical hotspots within forested landscapes: quantifying the functional role of vernal pools in ecosystem processes

    NASA Astrophysics Data System (ADS)

    Capps, K. A.; Rancatti, R.; Calhoun, A.; Hunter, M.

    2013-12-01

    Biogeochemical hotspots are characterized as small areas within a landscape matrix that show comparably high chemical reaction rates relative to surrounding areas. For small, natural features to generate biogeochemical hotspots within a landscape, their contribution to nutrient dynamics must be significant relative to nutrient demand of the surrounding landscape. In northeastern forests in the US, vernal pools are abundant, small features that typically fill in spring with snow melt and precipitation and dry by the end of the summer. Ephemeral flooding alters soil moisture and the depth of the oxic/anoxic boundary in the soil, which may affect leaf-litter decomposition rates and nutrient dynamics including denitrification. Additionally, pool-breeding organisms may influence nutrient dynamics via consumer-driven nutrient remineralization. We studied the effects of vernal pools on rates of leaf-litter decomposition and denitrification in forested habitats in Maine. Our results indicate leaf-litter decomposition and denitrification rates in submerged habitats of vernal pools were greater than in upland forest habitat. Our data also suggest pool-breeding organisms, such as wood frogs, may play an important role in nutrient dynamics within vernal pools. Together, the results suggest vernal pools may function as biogeochemical hotspots within forested landscapes.

  8. Effect of hotspot position fluctuation to writing capability in heated-dot magnetic recording

    NASA Astrophysics Data System (ADS)

    Tipcharoen, Warunee; Warisarn, Chanon; Kaewrawang, Arkom; Kovintavewat, Piya

    2016-07-01

    This work presents the effect of hotspot position fluctuation to writing capability in heated-dot magnetic recording systems at an areal density (AD) beyond 2 Tbpsi via a micromagnetic modeling. At high ADs, the hotspot and the write field gradient may not be correctly focused on the target island because the bit islands are closely positioned to one another. This may lead to the overwriting/erasing of the previously written islands, which can severely affect the recording performance. Therefore, this work studies the 3-by-3 data patterns that easily cause an error when the hotspot and write head positions are fluctuated by various island pitches. Simulation results indicate that the data pattern that leads to the highest/lowest error occurrence frequency is the one with the first, second and fourth islands having the opposite/same magnetization direction to/as the write field, regardless of the magnetization direction of the third island. This result can, for example, be utilized to design a two-dimensional modulation code to prevent such destructive data patterns, thus helping enhance the overall system performance.

  9. Effects of gill-net fishing on marine birds in a biological hotspot in the northwest Atlantic.

    PubMed

    Davoren, Gail K

    2007-08-01

    Marine biological hotspots, or areas where high abundances of species overlap in space and time, are ecologically important areas because energy flow through marine food webs, a key ecosystem process, is maximized in these areas. I investigated whether top predators aggregated at persistent spawning sites of a key forage fish species, capelin (Mallotus villosus), on the NE coast of Newfoundland during July and August 2000-2003. By examining the distributional patterns of top predators through ship-based surveys at multiple spatial and temporal scales, I found that the biomasses of birds-dominated by Common Murres (Uria aalge)-and mammals-dominated by whale species-were concentrated along the coast, with a biological hotspot forming near two persistent spawning sites of capelin in all years. The formation of this hotspot was well defined in space and time from middle of July to middle of August, likely coinciding with the spawning chronology of capelin. Within this hotspot, there was a high spatial and temporal overlap of Common Murres and gill nets set to capture Atlantic cod (Gadus morhua). This resulted in breeding murres becoming entangled in gill nets while feeding on spawning capelin. Despite an acknowledged uncertainty of bycatch mortality, estimates for the larger regional-scale area (1936-4973 murres/year; 0.2-0.6% of the breeding population) underestimated mortality relative to estimates within the hotspot (3053-14054 murres/year; 0.4-1.7%). Although fishing effort for Atlantic cod has declined substantially since the groundfish moratorium in 1992, chronic, unnatural, and additive mortality through bycatch continues in coastal Newfoundland. Restricted use of gill nets within this and other biological hotspots during the capelin spawning period appears to be a straightforward application of the "ecological and biologically significant area" management framework in Canada's Oceans Act. This protection would minimize murre bycatch and maintain ecosystem

  10. Hydrological droughts in the 21st century, hotspots and uncertainties from a global multimodel ensemble experiment

    PubMed Central

    Prudhomme, Christel; Giuntoli, Ignazio; Robinson, Emma L.; Clark, Douglas B.; Arnell, Nigel W.; Dankers, Rutger; Fekete, Balázs M.; Franssen, Wietse; Gerten, Dieter; Gosling, Simon N.; Hagemann, Stefan; Hannah, David M.; Kim, Hyungjun; Masaki, Yoshimitsu; Satoh, Yusuke; Stacke, Tobias; Wada, Yoshihide; Wisser, Dominik

    2014-01-01

    Increasing concentrations of greenhouse gases in the atmosphere are expected to modify the global water cycle with significant consequences for terrestrial hydrology. We assess the impact of climate change on hydrological droughts in a multimodel experiment including seven global impact models (GIMs) driven by bias-corrected climate from five global climate models under four representative concentration pathways (RCPs). Drought severity is defined as the fraction of land under drought conditions. Results show a likely increase in the global severity of hydrological drought at the end of the 21st century, with systematically greater increases for RCPs describing stronger radiative forcings. Under RCP8.5, droughts exceeding 40% of analyzed land area are projected by nearly half of the simulations. This increase in drought severity has a strong signal-to-noise ratio at the global scale, and Southern Europe, the Middle East, the Southeast United States, Chile, and South West Australia are identified as possible hotspots for future water security issues. The uncertainty due to GIMs is greater than that from global climate models, particularly if including a GIM that accounts for the dynamic response of plants to CO2 and climate, as this model simulates little or no increase in drought frequency. Our study demonstrates that different representations of terrestrial water-cycle processes in GIMs are responsible for a much larger uncertainty in the response of hydrological drought to climate change than previously thought. When assessing the impact of climate change on hydrology, it is therefore critical to consider a diverse range of GIMs to better capture the uncertainty. PMID:24344266

  11. High Resolution 40Ar/39Ar Geochronology of the Tuvalu Seamount Chain: Implications for Hotspot Longevity and Pacific Plate Motion.

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

    The Tuvalu seamount chain is a Mid-Pacific (4-11oS, 175-179oE) linear volcanic chain that was previously poorly sampled. Absolute plate motion (APM) models predict a long-lived relationship with hotspot activity in French Polynesia. The lack of detailed age data therefore results in a key chronologic gap in the geologic history of this hotspot and current APM models. Depending on the set of assumptions employed, previous APM models have disagreed on which known hotspot chain, if any, the Tuvalu volcanoes are associated with. Based on APM modeling and geochemical affinities (HIMU, 206Pb/204Pb > 20), Konter et al. (2008) argue that Rurutu Island (French Polynesia) represents the modern location of the hotspot that contributed volcanism to the Tuvalu seamounts. This model traces the hotspot chain from Rurutu through the region of modern day Samoa, the Tuvalu seamounts, the Gilbert ridge, and into the North & South Wake islands. This hypothesis suggests that a single HIMU mantle reservoir can exist and remain relatively geochemically consistent over 100 Myrs. On the contrary, the Wessel and Kroenke (2008) APM model suggest the Tuvalu seamounts and N & S Wake are unrelated. This model requires the N & S Wake chains to rotate significantly at the young end of the Gilbert Ridge resulting in a current hotspot location around 13-15oS and 156-155oW, away from any known active volcanism. During the summer of 2013, 25 Tuvaluan seamounts and 9 seamounts near the current Samoan chain were dredged onboard the R.V. Roger Revelle (expedition RR1310). Here we present 43 new 40Ar-39Ar ages covering 19 Tuvaluan seamounts and four seamounts within the Samoan hotspot track. These ages provide insights into the contributing hotspot for Tuvaluan volcanism and provide a new reference frame for constraining Pacific APM models. The corresponding chemical analyses for a subset of these seamounts will be presented by Finlayson et al. (this volume). Konter, J. G. et al. One hundred million

  12. Hotspots and social background of urban traffic crashes: A case study in Cluj-Napoca (Romania).

    PubMed

    Benedek, József; Ciobanu, Silviu Marian; Man, Titus Cristian

    2016-02-01

    Mobility practices have changed dramatically in Romanian towns over the last 25 years, following the collapse of socialist mobility restrictions. Urban areas like Cluj-Napoca are facing both increasing immigration and car mobility, and therefore increasing levels of road traffic crashes. The analysis of traffic crashes is one of the most important elements for improving the road safety policy. This paper is divided in two parts. In the first one, the authors focus on identifying the traffic crash hotspots along the street network, while in the second part they discuss the social background of road traffic crash occurrence. The first step in analyzing traffic crashes is to determine crash hotspots. A four-year record (2010-2013) provided by the Traffic Department of the General Inspectorate of Romanian Police (GIRPTD) was used. As a method of hotspot determination, the Kernel Density Estimation tool was employed, in the frame of the spatial analysis along network (SANET). The outcome was the hotspot map of traffic crashes in Cluj-Napoca. The results have revealed 4 categories of street segments: not-dangerous, low-dangerous, medium-dangerous and high-dangerous. Based on this classification, at least 4 dangerous areas were identified, located at the city entrances-exits (in the West, North-West and East) and the city center (the most dangerous zone). The second part of the paper focuses on social groups involved in car crashes. The following are considered: age, gender and blood alcohol concentration of the person (driver or pedestrian) found guilty for every individual crash. PMID:26680130

  13. Identification of water quality degradation hotspots in developing countries by applying large scale water quality modelling

    NASA Astrophysics Data System (ADS)

    Malsy, Marcus; Reder, Klara; Flörke, Martina

    2014-05-01

    Decreasing water quality is one of the main global issues which poses risks to food security, economy, and public health and is consequently crucial for ensuring environmental sustainability. During the last decades access to clean drinking water increased, but 2.5 billion people still do not have access to basic sanitation, especially in Africa and parts of Asia. In this context not only connection to sewage system is of high importance, but also treatment, as an increasing connection rate will lead to higher loadings and therefore higher pressure on water resources. Furthermore, poor people in developing countries use local surface waters for daily activities, e.g. bathing and washing. It is thus clear that water utilization and water sewerage are indispensable connected. In this study, large scale water quality modelling is used to point out hotspots of water pollution to get an insight on potential environmental impacts, in particular, in regions with a low observation density and data gaps in measured water quality parameters. We applied the global water quality model WorldQual to calculate biological oxygen demand (BOD) loadings from point and diffuse sources, as well as in-stream concentrations. Regional focus in this study is on developing countries i.e. Africa, Asia, and South America, as they are most affected by water pollution. Hereby, model runs were conducted for the year 2010 to draw a picture of recent status of surface waters quality and to figure out hotspots and main causes of pollution. First results show that hotspots mainly occur in highly agglomerated regions where population density is high. Large urban areas are initially loading hotspots and pollution prevention and control become increasingly important as point sources are subject to connection rates and treatment levels. Furthermore, river discharge plays a crucial role due to dilution potential, especially in terms of seasonal variability. Highly varying shares of BOD sources across

  14. Contrasting plant diversification histories within the Andean biodiversity hotspot.

    PubMed

    Pennington, R Toby; Lavin, Matt; Särkinen, Tiina; Lewis, Gwilym P; Klitgaard, Bente B; Hughes, Colin E

    2010-08-01

    The Andes are the most species-rich global biodiversity hotspot. Most research and conservation attention in the Andes has focused on biomes such as rain forest, cloud forest, and páramo, where much plant species diversity is the hypothesized result of rapid speciation associated with the recent Andean orogeny. In contrast to these mesic biomes, we present evidence for a different, older diversification history in seasonally dry tropical forests (SDTF) occupying rain-shadowed inter-Andean valleys. High DNA sequence divergence in Cyathostegia mathewsii, a shrub endemic to inter-Andean SDTF, indicates isolation for at least 5 million years of populations separated by only ca. 600 km of high cordillera in Peru. In conjunction with fossil evidence indicating the presence of SDTF in the Andes in the late Miocene, our data suggest that the disjunct small valley pockets of inter-Andean SDTF have persisted over millions of years. These forests are rich in endemic species but massively impacted, and merit better representation in future plans for science and conservation in Andean countries. PMID:20643954

  15. Incorporating evolutionary history into conservation planning in biodiversity hotspots

    PubMed Central

    Buerki, Sven; Callmander, Martin W.; Bachman, Steven; Moat, Justin; Labat, Jean-Noël; Forest, Félix

    2015-01-01

    There is increased evidence that incorporating evolutionary history directly in conservation actions is beneficial, particularly given the likelihood that extinction is not random and that phylogenetic diversity (PD) is lost at higher rates than species diversity. This evidence is even more compelling in biodiversity hotspots, such as Madagascar, where less than 10% of the original vegetation remains. Here, we use the Leguminosae, an ecologically and economically important plant family, and a combination of phylogenetics and species distribution modelling, to assess biodiversity patterns and identify regions, coevolutionary processes and ecological factors that are important in shaping this diversity, especially during the Quaternary. We show evidence that species distribution and community PD are predicted by watershed boundaries, which enable the identification of a network of refugia and dispersal corridors that were perhaps important for maintaining community integrity during past climate change. Phylogenetically clustered communities are found in the southwest of the island at low elevation and share a suite of morphological characters (especially fruit morphology) indicative of coevolution with their main dispersers, the extinct and extant lemurs. Phylogenetically over-dispersed communities are found along the eastern coast at sea level and may have resulted from many independent dispersal events from the drier and more seasonal regions of Madagascar. PMID:25561675

  16. Hotspot-mediated ultrafast nonlinear control of multifrequency plasmonic nanoantennas

    NASA Astrophysics Data System (ADS)

    Abb, Martina; Wang, Yudong; de Groot, C. H.; Muskens, Otto L.

    2014-09-01

    Plasmonic devices have a unique ability to concentrate and convert optical energy into a small volume. There is a tremendous interest in achieving active control of plasmon resonances, which would enable switchable hotspots for applications such as surface-enhanced spectroscopy and single molecule emission. The small footprint and strong-field confinement of plasmonic nanoantennas also holds great potential for achieving transistor-type devices for nanoscale-integrated circuits. To achieve such a functionality, new methods for nonlinear modulation are required, which are able to precisely tune the nonlinear interactions between resonant antenna elements. Here we demonstrate that resonant pumping of a nonlinear medium in a plasmonic hotspot produces an efficient transfer of optical Kerr nonlinearity between different elements of a multifrequency antenna. By spatially and spectrally separating excitation and readout, isolation of the hotspot-mediated ultrafast Kerr nonlinearity from slower, thermal effects is achieved.

  17. Cherenkov radiation imaging of beta emitters: in vitro and in vivo results

    NASA Astrophysics Data System (ADS)

    Spinelli, Antonello E.; Boschi, Federico; D'Ambrosio, Daniela; Calderan, Laura; Marengo, Mario; Fenzi, Alberto; Menegazzi, Marta; Sbarbati, Andrea; Del Vecchio, Antonella; Calandrino, Riccardo

    2011-08-01

    The main purpose of this work was to investigate both in vitro and in vivo Cherenkov radiation (CR) emission coming from 18F and 32P. The main difference between 18F and 32P is mainly the number of the emitted light photons, more precisely the same activity of 32P emits more CR photons with respect to 18F. In vitro results obtained by comparing beta counter measurements with photons average radiance showed that Cherenkov luminescence imaging (CLI) allows quantitative tracer activity measurements. In order to investigate in vivo the CLI approach, we studied an experimental xenograft tumor model of mammary carcinoma (BB1 tumor cells). Cherenkov in vivo dynamic whole body images of tumor bearing mice were acquired and the tumor tissue time activity curves reflected the well-known physiological accumulation of 18F-FDG in malignant tissues with respect to normal tissues. The results presented here show that it is possible to use conventional optical imaging devices for in vitro or in vivo study of beta emitters.

  18. The building of a biodiversity hotspot across a land-bridge in the Mediterranean.

    PubMed

    Molina-Venegas, Rafael; Aparicio, Abelardo; Lavergne, Sébastien; Arroyo, Juan

    2015-08-22

    Many of the macroevolutionary processes that have shaped present-day phylogenetic patterns were caused by geological events such as plate tectonics and temporary land-bridges. The study of spatial patterns of phylogenetic diversity can provide insights into these past events. Here we focus on a western Mediterranean biodiversity hotspot located in the southern Iberian Peninsula and northwest Africa, two regions that are separated by the Strait of Gibraltar. We explore the spatial structure of the phylogenetic relationships within and across large-scale plant assemblages. Significant turnover in terminal lineages tends to occur between landmasses, whereas turnover in deep lineages tends to occur within landmasses. Plant assemblages in the western ecoregions of this hotspot tend to be phylogenetically overdispersed but are phylogenetically clustered on its eastern margins. We discuss our results in the light of potential scenarios of niche evolution (or conservatism) and lineage diversification. The significant turnover between landmasses suggests a common scenario of allopatric speciation that could have been facilitated by the intermittent joining of the two continents. This may have constituted an important stimulus for diversification and the emergence of this western Mediterranean biodiversity hotspot. PMID:26246551

  19. Invasive Fishes Generate Biogeochemical Hotspots in a Nutrient-Limited System

    PubMed Central

    Capps, Krista A.; Flecker, Alexander S.

    2013-01-01

    Fishes can play important functional roles in the nutrient dynamics of freshwater systems. Aggregating fishes have the potential to generate areas of increased biogeochemical activity, or hotspots, in streams and rivers. Many of the studies documenting the functional role of fishes in nutrient dynamics have focused on native fish species; however, introduced fishes may restructure nutrient storage and cycling freshwater systems as they can attain high population densities in novel environments. The purpose of this study was to examine the impact of a non-native catfish (Loricariidae: Pterygoplichthys) on nitrogen and phosphorus remineralization and estimate whether large aggregations of these fish generate measurable biogeochemical hotspots within nutrient-limited ecosystems. Loricariids formed large aggregations during daylight hours and dispersed throughout the stream during evening hours to graze benthic habitats. Excretion rates of phosphorus were twice as great during nighttime hours when fishes were actively feeding; however, there was no diel pattern in nitrogen excretion rates. Our results indicate that spatially heterogeneous aggregations of loricariids can significantly elevate dissolved nutrient concentrations via excretion relative to ambient nitrogen and phosphorus concentrations during daylight hours, creating biogeochemical hotspots and potentially altering nutrient dynamics in invaded systems. PMID:23342083

  20. The building of a biodiversity hotspot across a land-bridge in the Mediterranean

    PubMed Central

    Molina-Venegas, Rafael; Aparicio, Abelardo; Lavergne, Sébastien; Arroyo, Juan

    2015-01-01

    Many of the macroevolutionary processes that have shaped present-day phylogenetic patterns were caused by geological events such as plate tectonics and temporary land-bridges. The study of spatial patterns of phylogenetic diversity can provide insights into these past events. Here we focus on a western Mediterranean biodiversity hotspot located in the southern Iberian Peninsula and northwest Africa, two regions that are separated by the Strait of Gibraltar. We explore the spatial structure of the phylogenetic relationships within and across large-scale plant assemblages. Significant turnover in terminal lineages tends to occur between landmasses, whereas turnover in deep lineages tends to occur within landmasses. Plant assemblages in the western ecoregions of this hotspot tend to be phylogenetically overdispersed but are phylogenetically clustered on its eastern margins. We discuss our results in the light of potential scenarios of niche evolution (or conservatism) and lineage diversification. The significant turnover between landmasses suggests a common scenario of allopatric speciation that could have been facilitated by the intermittent joining of the two continents. This may have constituted an important stimulus for diversification and the emergence of this western Mediterranean biodiversity hotspot. PMID:26246551

  1. Observing Volcanic Thermal Anomalies from Space: How Accurate is the Estimation of the Hotspot's Size and Temperature?

    NASA Astrophysics Data System (ADS)

    Zaksek, K.; Pick, L.; Lombardo, V.; Hort, M. K.

    2015-12-01

    Measuring the heat emission from active volcanic features on the basis of infrared satellite images contributes to the volcano's hazard assessment. Because these thermal anomalies only occupy a small fraction (< 1 %) of a typically resolved target pixel (e.g. from Landsat 7, MODIS) the accurate determination of the hotspot's size and temperature is however problematic. Conventionally this is overcome by comparing observations in at least two separate infrared spectral wavebands (Dual-Band method). We investigate the resolution limits of this thermal un-mixing technique by means of a uniquely designed indoor analog experiment. Therein the volcanic feature is simulated by an electrical heating alloy of 0.5 mm diameter installed on a plywood panel of high emissivity. Two thermographic cameras (VarioCam high resolution and ImageIR 8300 by Infratec) record images of the artificial heat source in wavebands comparable to those available from satellite data. These range from the short-wave infrared (1.4-3 µm) over the mid-wave infrared (3-8 µm) to the thermal infrared (8-15 µm). In the conducted experiment the pixel fraction of the hotspot was successively reduced by increasing the camera-to-target distance from 3 m to 35 m. On the basis of an individual target pixel the expected decrease of the hotspot pixel area with distance at a relatively constant wire temperature of around 600 °C was confirmed. The deviation of the hotspot's pixel fraction yielded by the Dual-Band method from the theoretically calculated one was found to be within 20 % up until a target distance of 25 m. This means that a reliable estimation of the hotspot size is only possible if the hotspot is larger than about 3 % of the pixel area, a resolution boundary most remotely sensed volcanic hotspots fall below. Future efforts will focus on the investigation of a resolution limit for the hotspot's temperature by varying the alloy's amperage. Moreover, the un-mixing results for more realistic multi

  2. Radiation-guided drug delivery to tumor blood vessels results in improved tumor growth delay.

    PubMed

    Geng, Ling; Osusky, Katherine; Konjeti, Sekhar; Fu, Allie; Hallahan, Dennis

    2004-10-19

    Tumor blood vessels are biological targets for cancer therapy. In this study, a tumor vasculature targeting system that consisted of liposomes and lectin (WGA) was built. Liposomes were used to carry a number of liposome-friendly anti-tumoral agents along with WGA, a lectin which posseses a specific affinity for binding to inflamed endothelial cells. In order to target tumor vasculature, inflammation of endothelial cells was induced by radiation. Because ionizing radiation induces an inflammatory response in tumor vasculature, lectin-conjugates were utilized to determine whether radiation can be used to target drug delivery to tumor vessels. Wheat germ agglutinin (WGA) is one such lectin that binds to inflamed microvasculature. WGA was conjugated to liposomes containing cisplatin and administered to tumor bearing mice. Tumor growth delay was used to analyze the efficacy of cytotoxicity. FITC-conjugated WGA accumulated within irradiated tumor microvasculature. WGA was conjugated to liposomes and labeled with 111In. This demonstrated radiation-inducible tumor-selective binding. WGA-liposome-conjugates were loaded with Cisplatin and administered to mice bearing irradiated tumors. Tumors treated with a combination of liposome encapsulated cisplatin together with radiation showed a significant increase in tumor growth delay as compared to radiation alone. These findings demonstrate that ionizing radiation can be used to guide drug delivery to tumor microvasculature. PMID:15451595

  3. Electric and magnetic hotspots in dielectric nanowire dimers.

    PubMed

    Mirzaei, Ali; Miroshnichenko, Andrey E

    2015-04-14

    We study the formation of the electric and magnetic near-field hotspots in dielectric cylindrical dimers. We compare dielectric and metallic dimers by using experimental data for all materials and consider both TM and TE polarizations of light. We demonstrate that dielectric dimers allow us to simultaneously achieve pure magnetic and electric near-field hotspots for both polarizations in contrast to plasmonic structures. This offers new approaches for near-field engineering such as sensing, control of spontaneous emission, and enhanced Raman scattering. PMID:25773044

  4. Particle radiation alters expression of matrix metalloproteases resulting in ECM remodeling in human lens cells.

    PubMed

    Chang, P Y; Bjornstad, K A; Rosen, C J; Lin, S; Blakely, E A

    2007-06-01

    Relatively low doses of space radiation have been correlated with an increased incidence and earlier appearance of cataracts in space travelers. The lens is a radiosensitive organ of the body with a very obvious late end point of radiation damage--cataract. However, many molecular changes occur in the lens soon after radiation exposure and long before the appearance of an opacification. The goal of our research is to elucidate early mechanisms associated with particle radiation-induced cataractogenesis, with the ultimate goal of developing countermeasures. Normal, cultured non-immortalized human lens cells were grown on matrix-coated plastic tissue culture vessels and irradiated with particle beams at Lawrence Berkeley National Lab (LBNL) or at the NASA Space Radiation Laboratory (NSRL) at Brookhaven National Lab. Samples were harvested at different times after radiation exposure. Using a focused genetic approach, total RNA and protein extracts from control and irradiated samples were processed and probed for the expression of genes associated with extracellular matrix (ECM) proteases. Matrix metalloproteinases (MMPs) have previously been studied in adult postmortem human lenses, in post-cataract intraocular lens (IOL) surgery capsular bags and with immortalized human lens cell cultures. Significant differences exist in the expression pattern with these various model systems. We have evidence for the cell stage-specific expression of MMP family of genes during lens fiber differentiation, and for radiation-induced alterations in the misregulation of MMP expression. Our data indicate that radiation exposure may lead to differences in the expression of radiation stress responses, which may impact selective ECM remodeling and cell differentiation. PMID:17256179

  5. Longitudinal hotspots in the mesospheric OH variations due to energetic electron precipitation

    NASA Astrophysics Data System (ADS)

    Andersson, M. E.; Verronen, P. T.; Rodger, C. J.; Clilverd, M. A.; Wang, S.

    2014-01-01

    Using Microwave Limb Sounder (MLS/Aura) and Medium Energy Proton and Electron Detector (MEPED/POES) observations between 2005-2009, we study the longitudinal response of nighttime mesospheric OH to radiation belt electron precipitation. Our analysis concentrates on geomagnetic latitudes from 55-72° N/S and altitudes between 70 and 78 km. The aim of this study is to better assess the spatial distribution of electron forcing, which is important for more accurate modelling of its atmospheric and climate effects. In the Southern Hemisphere, OH data show a hotspot, i.e. area of higher values, at longitudes between 150° W-30° E, i.e. poleward of the Southern Atlantic Magnetic Anomaly (SAMA) region. In the Northern Hemisphere, energetic electron precipitation-induced OH variations are more equally distributed with longitude. This longitudinal behaviour of OH can also be identified using Empirical Orthogonal Function analysis, and is found to be similar to that of MEPED-measured electron fluxes. The main difference is in the SAMA region, where MEPED appears to measure very large electron fluxes while MLS observations show no enhancement of OH. This indicates that in the SAMA region the MEPED observations are not related to precipitating electrons, at least not at energies >100 keV, but rather to instrument contamination. Analysis of selected OH data sets for periods of different geomagnetic activity levels shows that the longitudinal OH hotspot south of the SAMA (the Antarctic Peninsula region) is partly caused by strong, regional electron forcing, although atmospheric conditions also seem to play a role. Also, a weak signature of this OH hotspot is seen during periods of generally low geomagnetic activity, which suggests that there is a steady drizzle of high-energy electrons affecting the atmosphere, due to the Earth's magnetic field being weaker in this region.

  6. 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.

  7. 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.

  8. Hawaiian Hotspot - Spreading Ridge Interaction in the Late Cretaceous: A Fair and Balanced Look at the Evidence

    NASA Astrophysics Data System (ADS)

    Keller, R.

    2004-12-01

    As is so often the case in years divisible by 4, reality turns out to be quite different from reputation. The Hawaiian hotspot, often righteously promoted as the hotspot that the rest should strive to emulate, was not as stable nor as free from interactions with plate boundaries as some supporters suggest. Mounting geochemical and geophysical evidence shows that in its youth the hotspot not only inhaled, but probably snorted and did shots as well. The purpose of this presentation is to summarize what we know about the Late Cretaceous interaction between a spreading ridge and the Hawaiian hotspot from recent work on the Emperor Seamount chain. At the time of this writing, facts are a commodity to be fabricated, deleted, spun, denied, and denied-that-you-denied; but by the time of this presentation, we (hopefully) will be looking toward the future: can the Hawaiian hotspot's checkered past be treated as a bonus rather than a burden? Plate reconstructions of the Late Cretaceous northwest Pacific place a seafloor spreading center very close to, or even directly on top of, the Hawaiian hotspot. The geochemical effects of this hotspot-ridge interaction are now well documented by work on Ocean Drilling Program samples from Detroit Seamount, the next-to-oldest remaining Emperor Seamount. Basalts recovered from ODP Site 883 partway up the east side of Detroit Seamount have trace element and isotopic characteristics more akin to MORB than to Hawaiian Islands basalts. Basalts from ODP Site 884 at the eastern foot of the seamount are highly depleted tholeiites unlike anything else found so far in the Hawaiian-Emperor chain (Keller et al. 2000, Nature). Their trace element and radiogenic isotope values are essentially indistinguishable from MORB values (Keller et al. 2000), although triple-spike Pb isotope data are distinct from modern EPR MORB data (Regelous et al. 2003, J. Pet.). These characteristics were the result of the hotspot melting a greater proportion of a depleted

  9. Artificially induced hotspots in Bi2Sr2CaCu2O8 mesa terahertz sources

    NASA Astrophysics Data System (ADS)

    Hao, Yang; Welp, Ulrich; Koshelev, Alexei; Vlasko-Vlasov, Vitalii; Kwok, Wai-Kwong; Kadowaki, Kazuo; Benseman, Timothy

    Mesa-shaped devices comprising stacked Intrinsic Josephson Junctions (IJJs) in the high-temperature superconductor Bi2Sr2CaCu2O8 can be used as compact sources of coherent terahertz radiation. Achieving high emission levels of THz emission power from these devices depends on efficient synchronization of the approximately 600 IJJs in the stack. Theoretical simulations of stacked IJJs, as well as some empirical results, suggest that thermal inhomogeneity of the stack may enhance THz emission power. There are a number of possible mechanisms by which this might occur, including a hotspot acting as a local resistive shunt for the IJJs (thus altering the spread of bias voltages in the stack and the junction damping dynamics) or by local self-heating reducing the phase-stiffness of the superconducting condensate in critical locations. Here we report results of artificially inducing local heating in these devices with thin film micro-heaters patterned on their surfaces, in order to determine which mechanism(s) could be responsible for self-heating-induced THz emission enhancement. Sample patterning was performed at the Center for Nanoscale Materials, an Office of Science user facility, supported by the U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.

  10. Monitoring system for a synthesizer at SPring-8 synchrotron radiation facility and obtained results

    NASA Astrophysics Data System (ADS)

    Kawashima, Y.; Ego, H.; Hara, M.; Ohashi, Y.; Ohshima, T.; Takao, M.; Takashima, T.

    2013-02-01

    Beam orbit distortion in all dispersive sections was observed in the SPring-8 storage ring during beam commissioning. In order to confirm the stability of the radio frequency (RF) synthesizer, a monitoring system was developed. The system consists of a frequency counter referenced to a global positioning system (GPS) receiver. With this system, the output of the synthesizer, which uses an external 10 MHz-Rubidium atomic clock with the time accuracy of Δt/t=10-12, is correctly monitored with 11 digits absolute accuracy, verifying that the synthesizer works well. Measurement of the circumference of the SPring-8 storage ring reveals the effect of tidal forces and seasonal temperature variations on beam orbit. To maintain the center axis of photon radiation in experimental beam lines, a beam energy correction is carried out. The frequency of the RF synthesizer is changed every 5 min with 10-digit accuracy. This corresponds to an energy accuracy of ΔE/E=1.16×10-6. The monitoring system for the synthesizer and obtained results are described.

  11. 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.

  12. Carcinoma of the cervix stage IB: results of treatment with radiation therapy

    SciTech Connect

    Montana, G.S.; Fowler, W.C. Jr.; Varia, M.A.; Walton, L.A.; Kirsch, M.; Halle, J.S.; McCafferty, B.B.

    1983-01-01

    An analysis has been made of 101 patients treated with radiation therapy for epidermoid carcinoma of the cervix Stage IB (FIGO) from January 1970 through December 1976. The patients were treated with a combination of intracavitary therapy and external beam therapy delivering a total combined dose of 8000 rad to the paracervical areas (Points A/sub R/ and A/sub L/) and 5500 rad to the pelvic lymph nodes (Points I/sub R/ and I/sub L/). The cumulative, disease-free survival at 2, 3 and 5 years was 89% and 84%. Sixteen failures were recorded in this group of patients, of which 3 were a result of loco-regional disease, 5 loco-regional disease plus distant metastasis and 8 distant metastasis only. The failure rate was greater among the patients who had lesions 4 or more cm in diameter and in patients who received doses of external beam therapy to the whole pelvis of 4000 rad or more. Eighteen patients developed complications; however, one patient had a recto-vaginal and a vesico-vaginal fistula; thus 19 complications were recorded. The complications were divided according to their severity into three groups: Grade I (mild), Grade II (moderate) and Grade III (severe). There were 10 Grade I, 4 Grade II and 5 Grade III complications.

  13. Results from two workshops: Developing and amending regulations and funding state radiation control programs

    SciTech Connect

    Parker, G.

    1993-09-01

    The first section of this document presents the results of a technical workshop on the process of regulations development and amendment sponsored by the Nuclear Regulatory Commission (NRC). This workshop focused on methods for reducing the time it takes to promulgate regulations to help those States that are having difficulty meeting the three-year deadline for adopting new NRC regulations. Workshop participants responded to six questions, reviewed the procedures used by various States for revising and adopting changes to their regulations, and reviewed the time-flow charts used by various States. This workshop was designed to provide guidance to States that are promulgating and revising regulations. The second section of this document summarizes the proceedings of a technical workshop, also sponsored by the NRC, on funding radiation control programs that emphasized fee schedules and effective strategies for the 1990s. This workshop focused on determining the true costs of running a program, on setting realistic fees for the various categories of licenses, and on the most efficient methods for sending invoices, recording receipts, depositing money received, and issuing licenses. Workshop participants responded to seven questions; reviewed the methods various States use to determine true costs; reviewed the procedure that the various States use to produce invoices and licenses; reviewed the procedures that the States are required to abide by when they receive money; and reviewed the method used by the NRC to determine the cost of its various programs.

  14. First results from VIRTIS on Venus Express 2.Radiative transfer and atmospheric modelling

    NASA Astrophysics Data System (ADS)

    Drossart, P.; Piccioni, G.; Coradini, A.; Arnold, G.; Sémery, A.; Peter, G.; Cosi, M.; Pasqui, C.; Bézard, B.; Marinangeli, L.; Virtis Team

    The VIRTIS observations of Venus will provide information on various levels into the atmosphere The atmosphere above the cloud will be observed by Venus Express both on day and night side in solar reflection and thermal emission with different type of radiative transfer models adapted to the different atmospheric domains Limb observations are expected to give access to mesospheric CO 2 and CO emissions through fluorescence observations non-LTE modelling of CO 2 and CO bands will constrain the physical parameters of these layers Spectroscopy of the 4-5 micron range with VIRTIS-M and --H channels will give access to thermal structure retrieval and cloud structure at the 60-90 km altitude levels Finally the deeper atmospheric windows limited by CO 2 and H 2 O bands are accessible only in thermal emission on the night side The sounded levels at 2 3 1 7 mu m are limited respectively to 30-20 km altitude when at shorter wavelength 1 18 1 10 1 01 0 9 and 0 85 mu m the hot surface of Venus is seen through the scattering clouds Atmospheric modelling is therefore the key to decrypt the mysteries of Venus by ultimately removing atmospheric contributions to search for possible variations of surface emissivity Results on the different types of atmospheric contributions observed by VIRTIS will be shown if the Venus Express mission permits

  15. 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.

  16. 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.

  17. 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.

  18. 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

  19. Range-edge genetic diversity: locally poor extant southern patches maintain a regionally diverse hotspot in the seagrass Zostera marina.

    PubMed

    Diekmann, Onno E; Serrão, Ester A

    2012-04-01

    Refugial populations at the rear edge are predicted to contain higher genetic diversity than those resulting from expansion, such as in post-glacial recolonizations. However, peripheral populations are also predicted to have decreased diversity compared to the centre of a species' distribution. We aim to test these predictions by comparing genetic diversity in populations at the limits of distribution of the seagrass Zostera marina, with populations in the species' previously described central diversity 'hotspot'. Zostera marina populations show decreased allelic richness, heterozygosity and genotypic richness in both the 'rear' edge and the 'leading' edge compared to the diversity 'hotspot' in the North Sea/Baltic region. However, when populations are pooled, genetic diversity at the southern range is as high as in the North Sea/Baltic region while the 'leading edge' remains low in genetic diversity. The decreased genetic diversity in these southern Iberian populations compared to more central populations is possibly the effect of drift because of small effective population size, as a result of reduced habitat, low sexual reproduction and low gene flow. However, when considering the whole southern edge of distribution rather than per population, diversity is as high as in the central 'hotspot' in the North Sea/Baltic region. We conclude that diversity patterns assessed per population can mask the real regional richness that is typical of rear edge populations, which have played a key role in the species biogeographical history and as marginal diversity hotspots have very high conservation value. PMID:22369278

  20. Web-Based Application for Outliers Detection on Hotspot Data Using K-Means Algorithm and Shiny Framework

    NASA Astrophysics Data System (ADS)

    Mutiara Yoga Asmarani Suci, Agisha; Sukaesih Sitanggang, Imas

    2016-01-01

    Outliers analysis on hotspot data as an indicator of fire occurences in Riau Province between 2001 and 2012 have been done, but it was less helpful in fire prevention efforts. This is because the results can only be used by certain people and can not be easily and quickly accessed by users. The purpose of this research is to create a web-based application to detect outliers on Hotspot data and to visualize the outliers based on the time and location. Outliers detection was done in the previous research using the k-means clustering method with global and collective outlier approach in Riau Province Hotspot data between 2001 and 2012. This work aims to develop a web-based application using the framework Shiny with the R programming language. This application provides several functions including summary and visualization of the selected data, clustering hotspot data using k-means algorithm, visualization of the clustering results and sum square error (SSE), and displaying global and collective outliers and visualization of outlier spread on Riau Province Map.

  1. 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

  2. Rainfall-induced landslides in Europe: hotspots and thresholds (Invited)

    NASA Astrophysics Data System (ADS)

    Cepeda, J.; Jaedicke, C.; Nadim, F.; Kalsnes, B.

    2010-12-01

    This contribution presents preliminary results of the European project SafeLand. SafeLand is a large-scale integrating collaborative research project on landslide risks in Europe, funded by the Seventh Framework Programme for research and technological development (FP7) of the European Commission. SafeLand was launched in May 2009 and will run for three years. The project team, which comprises 27 institutions from 12 European countries, is coordinated by the International Centre for Geohazards (ICG) in Norway. SafeLand aims to develop and implement an integrated and comprehensive approach to help and guide decision-making in connection with mitigation of landslide risks. Quantifying the effects of global change (changes in demography and climate change) on evolution of landslide risk in Europe is one of the main goals of SafeLand. The methodologies are tested in selected hazard and risk "hotspots” in Europe, in turn improving knowledge, methodologies and integration strategies for the management of landslide risk. The present contribution is focused on two components of SafeLand: (1) the identification of landslide hazard and risk hotspots and (2) the estimation and assessment of rainfall thresholds for triggering of landslides. Hotspots of landslide hazard and risk were identified by an objective GIS-based analysis. The results show clearly where landslide pose the largest hazard in Europe and the objective approach allows a ranking of the countries by exposed area and population. In absolute numbers, Italy is the country with the highest amount of area and population exposed. Relative to absolute number of inhabitants and area, small alpine countries such as Lichtenstein and Montenegro score highest where as much as 40% of the population could be exposed. It is obvious that the type and quality of the input data are decisive for the quality of the results. Especially the estimation of extreme precipitation events needs improvement. These preliminary results are

  3. Large-scale motion between Pacific and Atlantic hotspots

    NASA Astrophysics Data System (ADS)

    Tarduno, John A.; Gee, Jeff

    1995-11-01

    STUDIES of true polar wander (TPW), the rotation of the solid Earth with respect to the spin axis1, have suggested that there has been 10-15° of relative motion over the past 130 Myr (refs 2-4). In such studies, the orientation of the spin axis is recovered from continental palaeomagnetic poles (corrected for relative plate motions), and compared with a deep-mantle reference frame defined by hotspot locations. But deducing relative plate motions becomes increasingly difficult for older (Mesozoic) time periods, hindering tests of TPW on timescales comparable to those of large-scale mantle convection; moreover, the assumption of hotspot fixity is controversial5,6. We examine here a more direct approach7,8, using palaeolatitudes derived from Pacific guyots. Contrary to predictions from TPW models, these data suggest only minor latitudinal shifts of Pacific hotspots during the Cretaceous period. Instead of TPW, relative motion between the Atlantic and Pacific hotspot groups9 is required at a velocity of approximately 30 mm yr-1, more than 50% larger than previously proposed5.

  4. Geologic evidence of hotspot activity of Venus - Predictions for Magellan

    NASA Technical Reports Server (NTRS)

    Stofan, Ellen R.; Saunders, R. Stephen

    1990-01-01

    A number of distinctive types of geologic features have been identified on Venus that are interpreted to be related to thermal plumes including domal rises, coronae, and major composite shield volcanoes. The basic characteristics of these features as well as their distribution are documented. The three types of features have related morphologies and are interpreted to represent a continuum of features formed by mantle plumes at scales from 100s to over 1000 km. The Artemis structure, located in Aphrodite Terra, is proposed to be a large corona. If crustal spreading processes are operating on Venus, hotspot features should form chains on the surface as seen in terrestrial ocean basins. On the basis of current data on hotspot-related feature distribution on Venus, no clear evidence exists for hotspot chains. The complete distribution of hotspot features in Magellan data will be used to understand better the relationship between interior processes and surface features, as well as to provide a test for the crustal spreading hypothesis.

  5. A Glance at Recombination Hotspots in the Domestic Cat.

    PubMed

    Alhaddad, Hasan; Zhang, Chi; Rannala, Bruce; Lyons, Leslie A

    2016-01-01

    Recombination has essential roles in increasing genetic variability within a population and in ensuring successful meiotic events. The objective of this study is to (i) infer the population-scaled recombination rate (ρ), and (ii) identify and characterize regions of increased recombination rate for the domestic cat, Felis silvestris catus. SNPs (n = 701) were genotyped in twenty-two East Asian feral cats (random bred). The SNPs covered ten different chromosomal regions (A1, A2, B3, C2, D1, D2, D4, E2, F2, X) with an average region size of 850 Kb and an average SNP density of 70 SNPs/region. The Bayesian method in the program inferRho was used to infer regional population recombination rates and hotspots localities. The regions exhibited variable population recombination rates and four decisive recombination hotspots were identified on cat chromosome A2, D1, and E2 regions. As a description of the identified hotspots, no correlation was detected between the GC content and the locality of recombination spots, and the hotspots enclosed L2 LINE elements and MIR and tRNA-Lys SINE elements. PMID:26859385

  6. Plant Conservation in the Caribbean Island Biodiversity Hotspot

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Caribbean Islands, comprising the Bahamas, Greater and Lesser Antilles and some islands located off the northern coast of South America, represent the most important insular system of the New World. As one of the 34 biodiversity hotspots, these islands represent a global priority for conservatio...

  7. A Glance at Recombination Hotspots in the Domestic Cat

    PubMed Central

    Alhaddad, Hasan; Zhang, Chi; Rannala, Bruce; Lyons, Leslie A.

    2016-01-01

    Recombination has essential roles in increasing genetic variability within a population and in ensuring successful meiotic events. The objective of this study is to (i) infer the population-scaled recombination rate (ρ), and (ii) identify and characterize regions of increased recombination rate for the domestic cat, Felis silvestris catus. SNPs (n = 701) were genotyped in twenty-two East Asian feral cats (random bred). The SNPs covered ten different chromosomal regions (A1, A2, B3, C2, D1, D2, D4, E2, F2, X) with an average region size of 850 Kb and an average SNP density of 70 SNPs/region. The Bayesian method in the program inferRho was used to infer regional population recombination rates and hotspots localities. The regions exhibited variable population recombination rates and four decisive recombination hotspots were identified on cat chromosome A2, D1, and E2 regions. As a description of the identified hotspots, no correlation was detected between the GC content and the locality of recombination spots, and the hotspots enclosed L2 LINE elements and MIR and tRNA-Lys SINE elements. PMID:26859385

  8. 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.

  9. 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. PMID:21632287

  10. 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.

  11. 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.

  12. 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.

  13. 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

  14. Response Modeling of Lightweight Charring Ablators and Thermal Radiation Testing Results

    NASA Technical Reports Server (NTRS)

    Congdon, William M.; Curry, Donald M.; Rarick, Douglas A.; Collins, Timothy J.

    2003-01-01

    Under NASA's In-Space Propulsion/Aerocapture Program, ARA conducted arc-jet and thermal-radiation ablation test series in 2003 for advanced development, characterization, and response modeling of SRAM-20, SRAM-17, SRAM-14, and PhenCarb-20 ablators. Testing was focused on the future Titan Explorer mission. Convective heating rates (CW) were as high as 153 W/sq cm in the IHF and radiation rates were 100 W/sq cm in the Solar Tower Facility. The ablators showed good performance in the radiation environment without spallation, which was initially a concern, but they also showed higher in-depth temperatures when compared to analytical predictions based on arc-jet thermal-ablation response models. More testing in 2003 is planned in both of these facility to generate a sufficient data base for Titan TPS engineering.

  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. PMID:27575352

  17. An overview of RADOM results for earth and moon radiation environment on Chandrayaan-1 satellite

    NASA Astrophysics Data System (ADS)

    Dachev, T. P.; Tomov, B. T.; Matviichuk, Yu. N.; Dimitrov, P. S.; Vadawale, S. V.; Goswami, J. N.; De Angelis, G.; Girish, V.

    2011-09-01

    The RADiatiOn Monitor (RADOM) is a miniature dosimeter-spectrometer that flew onboard the Chandrayaan-1 lunar mission in order to monitor the local radiation environment. Primary objective of the RADOM experiment was to measure the total absorbed dose, flux of surrounding energetic particles and spectrum of the deposited energy from high energy particles both en-route and in lunar orbit. RADOM was the first experiment to be switched on after the launch of Chandrayaan-1 and was operational until the end of the mission. This paper summarizes the observations carried out by RADOM during the entire life time (22 October 2008-31 August 2009) of the Chandrayaan-1 mission and compares the measurement by RADOM with the radiation belt models such as AP-8, AE-8 and CRRESS.

  18. 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. PMID:11537239

  19. Impacts Of Radiatively-Active Aerosols On Mars’ Current Climate: Simulation Results With The NASA ARC Mars GCM

    NASA Astrophysics Data System (ADS)

    Hollingsworth, Jeffery L.; Kahre, M. A.; Haberle, R. M.; Montmessin, F.; Herin, B.; Laamoumi, F.; Wilson, R. J.; Schaeffer, J.

    2010-10-01

    Recent upgrades to the NASA Ames Research Center (ARC) Mars general circulation model (GCM) include a fundamentally new and modernized radiative transfer package which permits radiative effects and interactions of suspended atmospheric aerosols (e.g., water ice clouds, water vapor, dust, and their mutual interactions) to influence the net diabatic heating rate within the atmosphere. Such aerosols are critically important in determining the nature of atmospheric thermal structure and hence the overall climate of the planet. Our Mars GCM simulations indicate that radiatively-active water ice clouds profoundly affect the seasonal and annual mean climate in a variety of ways. In particular, preliminary results suggest that the bulk thermal structure and resultant (i.e., balanced) circulation patterns are strongly modified near the surface and aloft. Generally speaking, we find a bulk warming of the atmosphere in upper layers, a cooling of the atmosphere in the lower and near-surface regions, and, increases in the mean pole-to-equator temperature contrasts (i.e., stronger mean polar vortices). A variety of results from our baseline and control simulations (i.e., where the radiative/physical effects are examined in isolation and when combined) will be presented. Comparisons with MGS/TES and MRO/MCS measurements indicate better agreement between the model's simulated climate compared to that observed. Using a state-of-the-art Mars GCM, these results highlight important effects radiatively-active aerosols have on physical and dynamical processes active in the current climate of Mars.

  20. Drivers and hotspots of extinction risk in marine mammals

    PubMed Central

    Davidson, Ana D.; Boyer, Alison G.; Kim, Hwahwan; Pompa-Mansilla, Sandra; Hamilton, Marcus J.; Costa, Daniel P.; Ceballos, Gerardo; Brown, James H.

    2012-01-01

    The world's oceans are undergoing profound changes as a result of human activities. However, the consequences of escalating human impacts on marine mammal biodiversity remain poorly understood. The International Union for the Conservation of Nature (IUCN) identifies 25% of marine mammals as at risk of extinction, but the conservation status of nearly 40% of marine mammals remains unknown due to insufficient data. Predictive models of extinction risk are crucial to informing present and future conservation needs, yet such models have not been developed for marine mammals. In this paper, we: (i) used powerful machine-learning and spatial-modeling approaches to understand the intrinsic and extrinsic drivers of marine mammal extinction risk; (ii) used this information to predict risk across all marine mammals, including IUCN “Data Deficient” species; and (iii) conducted a spatially explicit assessment of these results to understand how risk is distributed across the world's oceans. Rate of offspring production was the most important predictor of risk. Additional predictors included taxonomic group, small geographic range area, and small social group size. Although the interaction of both intrinsic and extrinsic variables was important in predicting risk, overall, intrinsic traits were more important than extrinsic variables. In addition to the 32 species already on the IUCN Red List, our model identified 15 more species, suggesting that 37% of all marine mammals are at risk of extinction. Most at-risk species occur in coastal areas and in productive regions of the high seas. We identify 13 global hotspots of risk and show how they overlap with human impacts and Marine Protected Areas. PMID:22308490

  1. Improving Trastuzumab's Stability Profile by Removing the Two Degradation Hotspots.

    PubMed

    Yang, Yuemei; Zhao, Jian; Geng, Shusheng; Hou, Chunmei; Li, Xingyin; Lang, Xiaoling; Qiao, Chunxia; Li, Yan; Feng, Jiannan; Lv, Ming; Shen, Beifen; Zhang, Boyan

    2015-06-01

    Stability of recombinant monoclonal antibodies (mAbs) is essential for their clinical application. The presence of the two degradation hotspots, namely, LC-Asn30 and HC-Asp102, in its complementary determinant regions prevents trastuzumab (Herceptin®) from being supplied in a drug product format of liquid formulation. To improve the stability, a new antibody was created by replacing the two residues with chemically similar amino acids of LC-Gln30 and HC-Glu102. This new mAb, named as T-mAb2, exhibited a simple and more uniform charge heterogeneity profile than T-mAb1, which is trastuzumab made in our laboratory, as displayed by the difference between their main peak area percentages (82.9% for T-mAb2 vs. 60.5% for T-mAb1). Computer modeling results, physicochemical and biological characterization, and stability profiling studies on T-mAb2 and T-mAb1 demonstrated that stability of T-mAb2 was significantly improved. In comparison with T-mAb1, although its in vitro human epidermal growth factor receptor 2 (HER2)-target binding activities were reduced slightly, in vivo tumor growth inhibiting activity was not affected, as demonstrated by the study results using the SKOV3 xenograft mouse model. Hence, a new anti-HER2 antibody was generated with improved stability that could be used to produce the drug product in liquid formulation for cost saving and more convenient usage. PMID:25820189

  2. Drivers and hotspots of extinction risk in marine mammals.

    PubMed

    Davidson, Ana D; Boyer, Alison G; Kim, Hwahwan; Pompa-Mansilla, Sandra; Hamilton, Marcus J; Costa, Daniel P; Ceballos, Gerardo; Brown, James H

    2012-02-28

    The world's oceans are undergoing profound changes as a result of human activities. However, the consequences of escalating human impacts on marine mammal biodiversity remain poorly understood. The International Union for the Conservation of Nature (IUCN) identifies 25% of marine mammals as at risk of extinction, but the conservation status of nearly 40% of marine mammals remains unknown due to insufficient data. Predictive models of extinction risk are crucial to informing present and future conservation needs, yet such models have not been developed for marine mammals. In this paper, we: (i) used powerful machine-learning and spatial-modeling approaches to understand the intrinsic and extrinsic drivers of marine mammal extinction risk; (ii) used this information to predict risk across all marine mammals, including IUCN "Data Deficient" species; and (iii) conducted a spatially explicit assessment of these results to understand how risk is distributed across the world's oceans. Rate of offspring production was the most important predictor of risk. Additional predictors included taxonomic group, small geographic range area, and small social group size. Although the interaction of both intrinsic and extrinsic variables was important in predicting risk, overall, intrinsic traits were more important than extrinsic variables. In addition to the 32 species already on the IUCN Red List, our model identified 15 more species, suggesting that 37% of all marine mammals are at risk of extinction. Most at-risk species occur in coastal areas and in productive regions of the high seas. We identify 13 global hotspots of risk and show how they overlap with human impacts and Marine Protected Areas. PMID:22308490

  3. Metropolitan urban hotspots of chronic sleep deprivation: evidence from a community health survey in Gyeongbuk Province, South Korea.

    PubMed

    Um, Sun-Bi; Um, Jung-Sup

    2015-01-01

    The geographic concentration of chronic sleep deprivation (CSD) remains largely unexplored. This paper examined the community-specific spatial pattern of the prevalence of CSD and the presence of clustered spatial hotspots among the Korean elderly population in Gyeongbuk Province, South Korea, revealing CSD hotspots and underscoring the importance of geography-focused prevention strategies. The study analysed cross-sectional data collected from 9847 elderly individuals aged 60 years and older who participated in a Korean Community Health Survey conducted in 2012. To assess the level of spatial dependence, an exploratory spatial data analysis was conducted using Global Moran's I statistic and the local indicator of spatial association. The results revealed marked geographic variations in CSD prevalence ranging from 33.4 to 73.4%, with higher values in the metropolitan urban areas and lower in the rural areas. Almost half of the community residents [both men (44.1%) and women (53.5%)] slept 6 h or less per 24 h. The average CSD prevalence (53.6% men and 65.1% women) in the hotspots was about 13.0% higher than that in other areas (42.6% for men and 51.1% for women). To our knowledge, this is the first study to generate a CSD hotspot map that includes data on sleep deprivation across metropolitan district levels. This study demonstrates that not only is sleep deprivation distributed differentially across communities but these differences may be explained by urbanisation. PMID:26618323

  4. Quantitative Trait Locus Analysis of Seed Germination and Seedling Vigor in Brassica rapa Reveals QTL Hotspots and Epistatic Interactions

    PubMed Central

    Basnet, Ram K.; Duwal, Anita; Tiwari, Dev N.; Xiao, Dong; Monakhos, Sokrat; Bucher, Johan; Visser, Richard G. F.; Groot, Steven P. C.; Bonnema, Guusje; Maliepaard, Chris

    2015-01-01

    The genetic basis of seed germination and seedling vigor is largely unknown in Brassica species. We performed a study to evaluate the genetic basis of these important traits in a B. rapa doubled haploid population from a cross of a yellow-seeded oil-type yellow sarson and a black-seeded vegetable-type pak choi. We identified 26 QTL regions across all 10 linkage groups for traits related to seed weight, seed germination and seedling vigor under non-stress and salt stress conditions illustrating the polygenic nature of these traits. QTLs for multiple traits co-localized and we identified eight hotspots for quantitative trait loci (QTL) of seed weight, seed germination, and root and shoot lengths. A QTL hotspot for seed germination on A02 mapped at the B. rapa Flowering Locus C (BrFLC2). Another hotspot on A05 with salt stress specific QTLs co-located with the B. rapa Fatty acid desaturase 2 (BrFAD2) locus. Epistatic interactions were observed between QTL hotspots for seed germination on A02 and A10 and with a salt tolerance QTL on A05. These results contribute to the understanding of the genetics of seed quality and seeding vigor in B. rapa and can offer tools for Brassica breeding. PMID:26648948

  5. A GIS-based spatiotemporal analysis of violent trauma hotspots in Vancouver, Canada: identification, contextualisation and intervention

    PubMed Central

    Walker, Blake Byron; Schuurman, Nadine; Hameed, S Morad

    2014-01-01

    Background In 2002, the WHO declared interpersonal violence to be a leading public health problem. Previous research demonstrates that urban spaces with a high incidence of violent trauma (hotspots) correlate with features of built environment and social determinants. However, there are few studies that analyse injury data across the axes of both space and time to characterise injury–environment relationships. This paper describes a spatiotemporal analysis of violent injuries in Vancouver, Canada, from 2001 to 2008. Methods Using geographic information systems, 575 violent trauma incidents were mapped and analysed using kernel density estimation to identify hotspot locations. Patterns between space, time, victim age and sex and mechanism of injury were investigated with an exploratory approach. Results Several patterns in space and time were identified and described, corresponding to distinct neighbourhood characteristics. Violent trauma hotspots were most prevalent in Vancouver's nightclub district on Friday and Saturday nights, with higher rates in the most socioeconomically deprived neighbourhoods. Victim sex, age and mechanism of injury also formed strong patterns. Three neighbourhood profiles are presented using the dual axis of space/time to describe the hotspot environments. Conclusions This work posits the value of exploratory spatial data analysis using geographic information systems in trauma epidemiology studies and further suggests that using both space and time concurrently to understand urban environmental correlates of injury provides a more granular or higher resolution picture of risk. We discuss implications for injury prevention and control, focusing on education, regulation, the built environment and injury surveillance. PMID:24556240

  6. 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.

  7. 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.

  8. 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.

  9. Volatile sulfur compounds in foods as a result of ionizing radiation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ionizing radiation improves food safety and extends shelf life by inactivating food-borne pathogens and spoilage microorganisms. However, irradiation may induce the development of an off-odor, particularly at high doses. The off-odor has been called “irradiation odor”. Substantial evidence suggests ...

  10. 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 various…

  11. CM-SAF surface radiation budget: First results with AVHRR data

    NASA Astrophysics Data System (ADS)

    Hollmann, R.; Mueller, R. W.; Gratzki, A.

    In the phase of redefinition of the EUMETSAT ground segment seven so called Satellite Application Facilities (SAF) each of them serving dedicated user groups have been established in Europe. The SAF on climate monitoring (CM-SAF) will deliver a comprehensive set of climate variables, including from different cloud products, radiation budget at the top of the atmosphere, surface radiation budget and tropospheric humidity. A consistent dataset of cloud and radiation products in a high spatial resolution on a uniform grid is derived. The CM-SAF is a joint project of the German Meteorological Service, EUMETSAT and five other European Meteorological Services. It is dedicated to produce climate datasets using data from instruments onboard of METEOSAT Second Generation and polar orbiting satellites NOAA and METOP. After the development phase, the CM-SAF has started its initial operational phase in the end of 2003. In this context, the algorithms have been implemented at the processing centres and the processing of satellite data from the polar orbiting satellites of NOAA has commenced. This paper gives an overview of the first products of surface radiative fluxes and their validation with selected surface sites.

  12. 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.

  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. Global Natural Disaster Risk Hotspots: Transition to a Regional Approach

    NASA Astrophysics Data System (ADS)

    Lerner-Lam, A.; Chen, R.; Dilley, M.

    2005-12-01

    economic losses, are also limited. On one hand the data are adequate for general identification of areas of the globe that are at relatively higher single- or multiple-hazard risk than other areas. On the other hand they are inadequate for understanding the absolute levels of risk posed by any specific hazard or combination of hazards. Nevertheless it is possible to assess in general terms the exposure and potential magnitude of losses to people and their assets in these areas. Such information, although not ideal, can still be very useful for informing a range of disaster prevention and preparedness measures, including prioritization of resources, targeting of more localized and detailed risk assessments, implementation of risk-based disaster management and emergency response strategies, and development of long-term plans for poverty reduction and economic development. In addition to summarizing the results of the Hotspots Project, we discuss data collection issues and suggest methodological approaches for making the transition to more detailed regional and national studies. Preliminary results for several regional case studies will be presented.

  15. Combined radiation and burn injury results in exaggerated early pulmonary inflammation

    PubMed Central

    Palmer, Jessica L.; Deburghgraeve, Cory R.; Bird, Melanie D.; Hauer-Jensen, Martin; Chen, Michael M.; Yong, Sherri; Kovacs, Elizabeth J.

    2014-01-01

    Events such as a nuclear meltdown accident or nuclear attack have potential for severe radiation injuries. Radiation injury frequently occurs in combination with other forms of trauma, most often burns. Thus far, combined injury studies have focused mainly on skin wound healing and damage to the gut. Since both radiation exposure and remote burn have pulmonary consequences, we examined the early effects of combined injury on the lung. C57BL/6 male mice were subjected to 5 Gy of total body irradiation followed by a 15% total body surface area scald burn. Lungs from surviving animals were examined for evidence of inflammation and pneumonitis. At 48 hours post-injury, pathology of the lungs from combined injury mice showed greater inflammation compared to all other treatment groups, with marked red blood cell and leukocyte congestion of the pulmonary vasculature. There was excessive leukocyte accumulation, primarily neutrophils, in the vasculature and interstitium, with occasional cells in the alveolar space. At 24 and 48 hours post-injury, myeloperoxidase levels in lungs of mice given combined injury were elevated compared to all other treatment groups (p<0.01), confirming histological evidence of neutrophil accumulation. Pulmonary levels of the neutrophil chemoattractant KC (CXCL1) were 3 times above that of either injury alone (p<0.05). Further, monocyte chemotactic protein-1 (MCP-1, CCL2) was increased 2-fold and 3-fold compared to burn injury or radiation injury, respectively (p<0.05). Together, these data suggest that combined radiation and burn injury augments early pulmonary congestion and inflammation.. Currently, countermeasures for this unique type of injury are extremely limited. Further research is needed to elucidate the mechanisms behind the synergistic effects of combined injury in order to develop appropriate treatments. PMID:23899376

  16. 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

  17. Mapping trabecular disconnection "hotspots" in aged human spine and hip.

    PubMed

    Aaron, Jean E; Shore, Patricia A; Itoda, Mizuo; Morrison, Rory J M; Hartopp, Andrew; Hensor, Elizabeth M A; Hordon, Lesley D

    2015-09-01

    Trabecular bone disconnection is an independent factor in age-related skeletal failure where real termini (ReTm; rare in youth) may cause weakness disproportionate to tissue loss, yet their structural contribution at vulnerable locations remains uncertain. ReTm (previously recorded at the iliac crest) were mapped in "normal" aged vertebral bodies (T11-L5 autopsy; 20 females, 10 males) and corresponding proximal femora (autopsy; 10 females). Results were compared with biomechanically failed femora from orthopaedic subjects aged >58 yr (osteoporosis OP, 10 females; osteoarthritis OA, 10 females). A novel direct 2D/3D histological method was applied to large, thick (300 μm) slices superficially silver-stained to separate ReTm (unstained) from apparent termini (planar artefacts, brown). Light microscope field co-ordinates enabled ReTm mapping and statistical testing relative to i) sex, ii) tissue sector and iii) slicing plane. In men ReTm populations were small and random while in women they were large and sector-specific. In vertebrae they clustered anterior/superior being rare posterior/inferior; in the femoral head they concentrated distal/superior and also near the fovea, being fewer distal/inferior. A distribution polarity was evident with 100% more ReTm observed transversely (i.e., on tensile-related cross struts) than longitudinally (i.e., on compression-related vertical struts). Their numbers rose in OP (BV/TV<14%, microCT) and in OA (BV/TV>14%), remaining polarised and sector-specific in OP only. Comparative experimentation by marrow elution of an OP animal model demonstrated "floating segments" as a possible outcome. Conclusions were supported statistically that trabecular disconnection "hotspots" at vulnerable locations are sex- and sector-specific, mainly transaxial, and subject to disease modulation. PMID:25874446

  18. 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.

  19. 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

  20. Hotspot decorations map plasmonic patterns with the resolution of scanning probe techniques.

    PubMed

    Valev, V K; Silhanek, A V; Jeyaram, Y; Denkova, D; De Clercq, B; Petkov, V; Zheng, X; Volskiy, V; Gillijns, W; Vandenbosch, G A E; Aktsipetrov, O A; Ameloot, M; Moshchalkov, V V; Verbiest, T

    2011-06-01

    In high definition mapping of the plasmonic patterns on the surfaces of nanostructures, the diffraction limit of light remains an important obstacle. Here we demonstrate that this diffraction limit can be completely circumvented. We show that upon illuminating nanostructures made of nickel and palladium, the resulting surface-plasmon pattern is imprinted on the structures themselves; the hotspots (regions of local field enhancement) are decorated with overgrowths, allowing for their subsequent imaging with scanning-probe techniques. The resulting resolution of plasmon pattern imaging is correspondingly improved. PMID:21702624

  1. Radiation

    NASA Video Gallery

    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...

  2. 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.

  3. Radiation reduction of optical solitons resulting from higher order dispersion terms in the nonlinear Schrödinger equation

    NASA Astrophysics Data System (ADS)

    Beech, Robert; Osman, Frederick

    2005-10-01

    This paper will present the nonlinearity and dispersion effects involved in propagation of optical solitons, which can be understood by using a numerical routine to solve the nonlinear Schrödinger equation (NLSE). Here, Mathematica v5© (Wolfram, 2003) is used to explore in depth several features of optical solitons formation and propagation. These numerical routines were implemented through the use of Mathematica v5© and the results give a very clear idea of this interesting and important practical phenomenon. It is hoped that this work will open up an important new approach to the cause, effect, and correction of interference from secondary radiation found in the uses of soliton waves in lasers and in optical fiber telecommunication. It is believed that these results will be of considerable use in any work or research in this field and in self-focusing properties of the soliton (Osman et al., 2004a, 2004b; Hora, 1991). In a previous paper on this topic (Beech & Osman, 2004), it was shown that solitons of NLSE radiate. This paper goes on from there to show that these radiations only occur in solitons derived from cubic, or odd-numbered higher orders of NLSE, and that there are no such radiations from solitons of quadratic, or even-numbered higher order of NLSE. It is anticipated that this will stimulate research into practical means to control or eliminate such radiations.

  4. Some results of the propagation of the high-power terawatt femtosecond laser radiation in different media

    NASA Astrophysics Data System (ADS)

    Babushkin, P. A.; Burnashov, A. V.; Iglakova, A. N.; Kovaleva, S. F.; Medvedenko, I. A.

    2015-12-01

    The results of laboratory experiments and numerical calculation of propagation of high-power terawatt femtosecond laser radiation via different media (air, glass and water) are represented. The experiments have been made on femtosecond Ti:Sa-laser system of IAO SB RAS. The spatial features of high-power terawatt femtosecond laser radiation are presented also. The ability of control of the position of the beginning of the field filamentation and angle of divergence of supercontinuum on high-power terawatt femtosecond laser radiation via plane parallel plate (glass) are found. The values of the location of the high value of the backscattering depending on filamentation conditions and the characteristics of supercontinuum and lidar system are obtained. The ability of the remote sensing of cirrus clouds with the help of high-power terawatt femtosecond laser radiation is discussed. The results of interactions of high-power terawatt femtosecond laser radiation and ice hexagonal plate crystal depending upon location of this crystal and filamentation conditions are represented.

  5. Ozone database in support of CMIP5 simulations: results and corresponding radiative forcing

    NASA Astrophysics Data System (ADS)

    Cionni, I.; Eyring, V.; Lamarque, J. F.; Randel, W. J.; Stevenson, D. S.; Wu, F.; Bodeker, G. E.; Shepherd, T. G.; Shindell, D. T.; Waugh, D. W.

    2011-04-01

    ozone is overestimated in the southern polar latitudes during spring and tropospheric column ozone is slightly underestimated. Vertical profiles of tropospheric ozone are broadly consistent with ozonesondes and in-situ measurements, with some deviations in regions of biomass burning. The tropospheric ozone radiative forcing (RF) from the 1850s to the 2000s is 0.23 W m-2, lower than previous results. The lower value is mainly due to (i) a smaller increase in biomass burning emissions; (ii) a larger influence of stratospheric ozone depletion on upper tropospheric ozone at high southern latitudes; and possibly (iii) a larger influence of clouds (which act to reduce the net forcing) compared to previous radiative forcing calculations. Over the same period, decreases in stratospheric ozone, mainly at high latitudes, produce a RF of -0.08 W m-2, which is more negative than the central Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4) value of -0.05 W m-2, but which is within the stated range of -0.15 to +0.05 W m-2. The more negative value is explained by the fact that the regression model simulates significant ozone depletion prior to 1979, in line with the increase in EESC and as confirmed by CCMs, while the AR4 assumed no change in stratospheric RF prior to 1979. A negative RF of similar magnitude persists into the future, although its location shifts from high latitudes to the tropics. This shift is due to increases in polar stratospheric ozone, but decreases in tropical lower stratospheric ozone, related to a strengthening of the Brewer-Dobson circulation, particularly through the latter half of the 21st century. Differences in trends in tropospheric ozone among the four RCPs are mainly driven by different methane concentrations, resulting in a range of tropospheric ozone RFs between 0.4 and 0.1 W m-2 by 2100. The ozone dataset described here has been released for the Coupled Model Intercomparison Project (CMIP5) model simulations in net

  6. Ozone database in support of CMIP5 simulations: results and corresponding radiative forcing

    NASA Astrophysics Data System (ADS)

    Cionni, I.; Eyring, V.; Lamarque, J. F.; Randel, W. J.; Stevenson, D. S.; Wu, F.; Bodeker, G. E.; Shepherd, T. G.; Shindell, D. T.; Waugh, D. W.

    2011-11-01

    ozone is overestimated in the southern polar latitudes during spring and tropospheric column ozone is slightly underestimated. Vertical profiles of tropospheric ozone are broadly consistent with ozonesondes and in-situ measurements, with some deviations in regions of biomass burning. The tropospheric ozone radiative forcing (RF) from the 1850s to the 2000s is 0.23 W m-2, lower than previous results. The lower value is mainly due to (i) a smaller increase in biomass burning emissions; (ii) a larger influence of stratospheric ozone depletion on upper tropospheric ozone at high southern latitudes; and possibly (iii) a larger influence of clouds (which act to reduce the net forcing) compared to previous radiative forcing calculations. Over the same period, decreases in stratospheric ozone, mainly at high latitudes, produce a RF of -0.08 W m-2, which is more negative than the central Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4) value of -0.05 W m-2, but which is within the stated range of -0.15 to +0.05 W m-2. The more negative value is explained by the fact that the regression model simulates significant ozone depletion prior to 1979, in line with the increase in EESC and as confirmed by CCMs, while the AR4 assumed no change in stratospheric RF prior to 1979. A negative RF of similar magnitude persists into the future, although its location shifts from high latitudes to the tropics. This shift is due to increases in polar stratospheric ozone, but decreases in tropical lower stratospheric ozone, related to a strengthening of the Brewer-Dobson circulation, particularly through the latter half of the 21st century. Differences in trends in tropospheric ozone among the four RCPs are mainly driven by different methane concentrations, resulting in a range of tropospheric ozone RFs between 0.4 and 0.1 W m-2 by 2100. The ozone dataset described here has been released for the Coupled Model Intercomparison Project (CMIP5) model simulations in net

  7. 60Co contamination in recycled steel resulting in elevated civilian radiation doses: causes and challenges.

    PubMed

    Chang, W P; Chan, C C; Wang, J D

    1997-09-01

    Since late 1992, more than 100 building complexes containing public and private schools and nearly 1,000 apartments have been identified in Taiwan with elevated levels of gamma-radiation from construction steel contaminated with 60Co. Due to improper handling of 60Co contaminated scrap steel in late 1982 and 1983, contaminated construction materials have been widely distributed throughout the country. These contaminated construction materials have generated elevated radiation exposures to members of the public in Taiwan. As of early 1996, more than 4,000 people, including young students, have been identified as receiving more than 1 mSv y(-1) above the local background for up to 12 y. This report provides a detailed discussion of the sources of the 60Co contamination in construction steel, its discovery in the building complexes, and preliminary evaluation and remediation activities. PMID:9287087

  8. Radiation doses in adult computed tomography practice in Serbia: initial results.

    PubMed

    Arandjic, Danijela; Ciraj-Bjelac, Olivera; Hadnadjev, Darka; Stojanovic, Sanja; Bozovic, Predrag; Ceklic, Sandra; Lazarevic, Djordje

    2014-11-01

    This work presents initial data on radiation doses in adult computed tomography (CT) in Serbia. Data were collected in terms of CT dose index (CTDIvol) and dose length product (DLP) values for head, chest and abdomen examination. The range of CTDIvol values was found to be 53-98, 11-34 and 8.5-227 mGy whereas for DLP was 803-1066, 350-845 and 1066-3078 mGy cm(-1) for head, chest and abdomen examination, respectively. Except for abdomen on one CT unit, all estimated values were in line with the reported data. This work also presents simple method on how to reduce radiation doses when scanning head. Using axial (step-and-shot) instead of helical mode and decreasing tube current-time product leads to significant dose reduction. CTDIvol was decreased by 20 % whereas DLP was reduced for a factor 2. PMID:25063787

  9. Results of radiation therapy in early glottic carcinoma (T1, T2 N0).

    PubMed

    Stein, M; Rosenblatt, E; Kuten, A; Cohen, Y

    1989-03-01

    Glottic carcinoma is curable by either surgery or radiotherapy. A total of 60 patients were treated by radiation alone at the Northern Israel Oncology Center, Rambam Medical Center, Haifa, between 1970 and 1980. Twenty-nine (48%) were classified as T1 N0 and 31 (52%) as T2 N0. All patients received radiotherapy primarily with curative intent, with surgery reserved for recurrences. The 5-year actuarial survival for all patients was 90% and actuarial disease-free survival was 95%. In ten patients (17%) there was local failure, and five of them were salvaged by surgery. There were no significant acute or long-term complications of radiation. Factors influencing treatment outcome (anterior commissures involvement, degree of differentiation, treatment volume, and technique of irradiation) and the occurrence of second primary malignancies are discussed. PMID:2918722

  10. Cosmic radiation and cancer mortality among airline pilots: results from a European cohort study (ESCAPE).

    PubMed

    Langner, I; Blettner, M; Gundestrup, M; Storm, H; Aspholm, R; Auvinen, A; Pukkala, E; Hammer, G P; Zeeb, H; Hrafnkelsson, J; Rafnsson, V; Tulinius, H; De Angelis, G; Verdecchia, A; Haldorsen, T; Tveten, U; Eliasch, H; Hammar, N; Linnersjö, A

    2004-02-01

    Cosmic radiation is an occupational risk factor for commercial aircrews. In this large European cohort study (ESCAPE) its association with cancer mortality was investigated on the basis of individual effective dose estimates for 19,184 male pilots. Mean annual doses were in the range of 2-5 mSv and cumulative lifetime doses did not exceed 80 mSv. All-cause and all-cancer mortality was low for all exposure categories. A significant negative risk trend for all-cause mortality was seen with increasing dose. Neither external and internal comparisons nor nested case-control analyses showed any substantially increased risks for cancer mortality due to ionizing radiation. However, the number of deaths for specific types of cancer was low and the confidence intervals of the risk estimates were rather wide. Difficulties in interpreting mortality risk estimates for time-dependent exposures are discussed. PMID:14648170

  11. Geographic Variations in Hotspot Geochemistry Caused by 3D Dynamics and Melting of a Heterogeneous Mantle Plume

    NASA Astrophysics Data System (ADS)

    Bianco, T. A.; Ito, G.; van Hunen, J.; Ballmer, M.; Mahoney, J. J.

    2006-12-01

    Spatial variations in magma geochemistry among hotspot volcanoes hold clues to the dynamics and composition of the mantle feeding hotspot volcanism. We use a 3D geodynamic model of plume-lithosphere interaction to explore the causes of spatial patterns of magmatic volumes and compositions at intraplate hotspots. This study focuses on coupling between upper mantle flow, heat transfer, and melting of a heterogeneous (veined) plume. We assume multiple lithologies have different solidi, trace-element, and isotope composition. We use the Cartesian finite-element code, CITCOM, (Zhong and Watts, 2002) to simulate mantle convection with the extended Boussinesq approximation in a volume of upper mantle 400 km in thickness. A parameterized melting model is used to simulate melting of materials with different water contents (Katz et al., 2003). Melt depletion (F) for each lithology is calculated at finite element nodes as a function of temperature, pressure, and water content and is advected using particle tracers. We quantify the response of the geographic pattern of the volume and composition of magmas to different lithospheric thicknesses, and plume temperatures and viscosities, which together control the melting rates and sizes of the melting zones for the different lithologies. In the case of two-lithologies, preliminary results of a sluggishly convecting plume rising beneath thick lithosphere (60-100 km) predict that the melting zone of the least refractory "lithology 1" is wider than that of the more refractory "lithology 2". This leads to the prediction that on the surface, the isotope signature of lithology 1 is most prominent at the leading edge (i.e., upwind edge of plate motion) of the hotspot, whereas the isotope signature of lithology 2 is strongest at the hotspot center. This pattern will likely change for plumes convecting more vigorously or thinner lithosphere.

  12. Rainfall hotspots over the southern tropical Andes: Spatial distribution, rainfall intensity, and relations with large-scale atmospheric circulation

    NASA Astrophysics Data System (ADS)

    Espinoza, Jhan Carlo; Chavez, Steven; Ronchail, Josyane; Junquas, Clémentine; Takahashi, Ken; Lavado, Waldo

    2015-05-01

    The Andes/Amazon transition is among the rainiest regions of the world and the interactions between large-scale circulation and the topography that determine its complex rainfall distribution remain poorly known. This work provides an in-depth analysis of the spatial distribution, variability, and intensity of rainfall in the southern Andes/Amazon transition, at seasonal and intraseasonal time scales. The analysis is based on comprehensive daily rainfall data sets from meteorological stations in Peru and Bolivia. We compare our results with high-resolution rainfall TRMM-PR 2A25 estimations. Hotspot regions are identified at low elevations in the Andean foothills (400-700 masl) and in windward conditions at Quincemil and Chipiriri, where more than 4000 mm rainfall per year are recorded. Orographic effects and exposure to easterly winds produce a strong annual rainfall gradient between the lowlands and the Andes that can reach 190 mm/km. Although TRMM-PR reproduces the spatial distribution satisfactorily, it underestimates rainfall by 35% in the hotspot regions. In the Peruvian hotspot, exceptional rainfall occurs during the austral dry season (around 1000 mm in June-July-August; JJA), but not in the Bolivian hotspot. The direction of the low-level winds over the Andean foothills partly explains this difference in the seasonal rainfall cycle. At intraseasonal scales in JJA, we found that, during northerly wind regimes, positive rainfall anomalies predominate over the lowland and the eastern flank of the Andes, whereas less rain falls at higher altitudes. On the other hand, during southerly regimes, rainfall anomalies are negative in the hotspot regions. The influence of cross-equatorial winds is particularly clear below 2000 masl.

  13. Radiation Dose Survey for Common Computed Tomography Exams: 2013 British Columbia Results.

    PubMed

    Thakur, Yogesh; Bjarnason, Thorarin A; Baxter, Patricia; Griffith, Mitch; Eaton, Kirk

    2016-02-01

    In 2013 Health Canada conducted a national survey of computed tomography (CT) radiation usage. We analysed contributions from all 7 public health authorities in the province of British Columbia, which covered scanner age, number of slices, and common adult protocols (≥ 19 years: 70 ± 20 kg, head, chest, abdomen/pelvis, and trunk). Patient doses were recorded for common protocols. Diagnostic reference levels (DRLs) was calculated using scanner data with >10 patient doses recorded for each protocol. Data was analysed based on image reconstruction (filtered backprojection vs iterative reconstruction [IR] vs IR available but not in use). Provincial response was 92%, with 59 of 64 CT data used for analysis. The average scanner age was 5.5 years old, with 39% of scanners installed between 2008-2013; 78.5% of scanners were multislice (>64 slices), and 44% of scanners had IR available. Overall British Columbia DRLs were: head = 1305, chest = 529, abdomen/pelvis = 819, and trunk = 1225. DRLs were consistent with Health Canada recommendations and other Canadian published values, but above international standards. For sites with IR available, less than 50% used this technology routinely for head, chest and trunk exams. Overall, use of IR reduced radiation usage between 11%-32% compared to filtered backprojection, while sites using IR vs IR available used 30%/43% less radiation for head/chest exams (P < .05). No significant difference was observed for abdomen/pelvis exams (P = .385). With the fast pace of CT technical advancement, DRLs should reflect the technology used, instead of just globally applied to anatomical regions. Federal guidelines should be updated at a higher frequency to reflect new technology. In addition, new technologies must be utilised to optimize image quality vs radiation usage. PMID:26608253

  14. Saturnian trapped radiation and its absorption by satellites and rings: the first results from pioneer 11.

    PubMed

    Simpson, J A; Bastian, T S; Chenette, D L; Lentz, G A; McKibben, R B; Pyle, K R; Tuzzolino, A J

    1980-01-25

    Electrons and protons accelerated and trapped in a Saturnian magnetic field have been found by the University of Chicago experiments on Pioneer 11 within 20 Saturn radii (Rs) of the planet. In the innermost regions, strong absorption effects due to satellites and ring material were observed, and from approximately 4 Rs inwards to the outer edge of the A ring at 2.30 Rs (where the radiation is absorbed), the intensity distributions of protons (>/= 0.5 million electron volts) and electrons (2 to 20 million electron volts) were axially symmetric, consistent with a centered dipole aligned with the planetary rotation axis. The maximum fluxes observed for protons (> 35 million electron volts and for electrons < 3.4 million electron volts) were 3 x 10(4) and 3 x 10(6) per square centimeter per second, respectively. Absorption of radiation by Mimas provides a means of estimating the radial diffusion coefficient for charged particle transport. However, the rapid flux increases observed between absorption features raise new questions concerning the physics of charged particle transport and acceleration. An absorption feature near 2.5 Rs has led to the discovery of a previously unknown satellite with a diameter of approximately 200 kilometers, semimajor axis of 2.51 Rs, and eccentricity of 0.013. Radiation absorption features that suggest a nonuniform distribution of matter around Saturn have also been found from 2.34 to 2.36 Rs, near the position of the F ring discovered by the Pioneer imaging experiment. Beneath the A, B, and C rings we continued to observe a low flux of high-energy electrons. We conclude that the inner Saturn magnetosphere, because of its near-axial symmetry and the many discrete radiation absorption regions, offers a unique opportunity to study the acceleration and transport of charged particles in a planetary magnetic field. PMID:17833550

  15. Long-term results and complications of preoperative radiation in the treatment of rectal cancer

    SciTech Connect

    Reed, W.P.; Garb, J.L.; Park, W.C.; Stark, A.J.; Chabot, J.R.; Friedmann, P.

    1988-02-01

    A retrospective study of 149 patients with rectal cancer diagnosed between 1972 and 1979 was undertaken to compare survival, disease-free survival, recurrence sites, and long-term complications of 40 patients who received 4000 to 4500 rads of preoperative adjuvant radiotherapy (radiation group) with those of 109 patients treated by resection alone (control group). After a mean follow-up of 84 months and 99 months, respectively, survival of the irradiated patients was significantly better than that of controls (68% versus 52%, p less than 0.05). Disease-free survival of those patients rendered free of disease by treatment was also superior for the irradiated group (84% versus 57%, p less than 0.005). Local recurrence without signs of distant metastases developed only one-third as often in irradiated patients (6% versus 18%). Distant metastases, alone or in combination with local recurrence, were also less common after radiation (12% versus 27%). Second primary tumors developed in 15% and 10% of the respective groups, a difference that was not statistically significant. When we consider the survival benefit of preoperative radiation therapy, long-term complications were relatively mild. Delayed healing of the perineum was noted in two irradiated patients. Persistent diarrhea was severe enough to warrant treatment in only one case, and one patient required a colostomy for intestinal obstruction from pelvic fibrosis.

  16. Effect of Estimated Daily Global Solar Radiation Data on the Results of Crop Growth Models

    PubMed Central

    Trnka, Miroslav; Eitzinger, Josef; Kapler, Pavel; Dubrovský, Martin; Semerádová, Daniela; Žalud, Zden ěk; Formayer, Herbert

    2007-01-01

    The results of previous studies have suggested that estimated daily global radiation (RG) values contain an error that could compromise the precision of subsequent crop model applications. The following study presents a detailed site and spatial analysis of the RG error propagation in CERES and WOFOST crop growth models in Central European climate conditions. The research was conducted i) at the eight individual sites in Austria and the Czech Republic where measured daily RG values were available as a reference, with seven methods for RG estimation being tested, and ii) for the agricultural areas of the Czech Republic using daily data from 52 weather stations, with five RG estimation methods. In the latter case the RG values estimated from the hours of sunshine using the Ångström-Prescott formula were used as the standard method because of the lack of measured RG data. At the site level we found that even the use of methods based on hours of sunshine, which showed the lowest bias in RG estimates, led to a significant distortion of the key crop model outputs. When the Ångström-Prescott method was used to estimate RG, for example, deviations greater than ±10 per cent in winter wheat and spring barley yields were noted in 5 to 6 per cent of cases. The precision of the yield estimates and other crop model outputs was lower when RG estimates based on the diurnal temperature range and cloud cover were used (mean bias error 2.0 to 4.1 per cent). The methods for estimating RG from the diurnal temperature range produced a wheat yield bias of more than 25 per cent in 12 to 16 per cent of the seasons. Such uncertainty in the crop model outputs makes the reliability of any seasonal yield forecasts or climate change impact assessments questionable if they are based on this type of data. The spatial assessment of the RG data uncertainty propagation over the winter wheat yields also revealed significant differences within the study area. We found that RG estimates based on

  17. Preliminary results on soil-emitted gamma radiation and its relation with the local atmospheric electric field at Amieira (Portugal)

    NASA Astrophysics Data System (ADS)

    Lopes, F.; Silva, H. G.; Bárias, S.; Barbosa, S. M.

    2015-10-01

    The atmospheric electric field near the Earth's surface is dominated by atmospheric pollutants and natural radioactivity, with the latter directly linked to radon (222Rn) gas. For a better comprehension on the temporal variability of both the atmospheric electric field and the radon concentration and its relation with local atmospheric variables, simultaneous measurements of soil-emitted gamma radiation and potential gradient (defined from the vertical component of the atmospheric electric field) were taken every minute, along with local meteorological parameters (e.g., temperature, atmospheric pressure, relative humidity and daily solar radiation). The study region is Amieira, part of the Alqueva lake in Alentejo Portugal, where an interdisciplinary meteorological campaign, ALEX2014, took place from June to August 2014. Soil gamma radiation is more sensitive to small concentrations of radon as compared with alpha particles measurements, for that reason it is more suited for sites with low radon levels, as expected in this case. Preliminary results are presented here: statistical and spectral analysis show that i) the potential gradient has a stronger daily cycle as compared with the gamma radiation, ii) most of the energy of the gamma signal is concentrated in the low frequencies (close to 0), contrary to the potential gradient that has most of the energy in frequency 1 (daily cycle) and iii) a short-term relation between gamma radiation and the potential gradient has not been found. Future work and plans are also discussed.

  18. A 3-D Model of Hot-Spot Formation in Inertial Confinement Fusion Implosions

    NASA Astrophysics Data System (ADS)

    Gong, X.; Goncharov, V. N.; Igumenshchev, I. V.

    2015-11-01

    A 3-D model describing the formation of a hot-spot in inertial confinement fusion (ICF) implosions is presented. The model includes thermal conduction and mass ablation effects in a 3-D distorted hot spot using an approach developed by Sanz. Evolution of the nonuniformity growth is calculated based on a sharp boundary model. The results of the model will be compared against 2-D DRACO and 3-D hydrodynamic code calculations. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

  19. Preferential Formation of Benzo[a]pyrene Adducts at Lung Cancer Mutational Hotspots in P53

    NASA Astrophysics Data System (ADS)

    Denissenko, Mikhail F.; Pao, Annie; Tang, Moon-Shong; Pfeifer, Gerd P.

    1996-10-01

    Cigarette smoke carcinogens such as benzo[a]pyrene are implicated in the development of lung cancer. The distribution of benzo[a]pyrene diol epoxide (BPDE) adducts along exons of the P53 gene in BPDE-treated HeLa cells and bronchial epithelial cells was mapped at nucleotide resolution. Strong and selective adduct formation occurred at guanine positions in codons 157, 248, and 273. These same positions are the major mutational hotspots in human lung cancers. Thus, targeted adduct formation rather than phenotypic selection appears to shape the P53 mutational spectrum in lung cancer. These results provide a direct etiological link between a defined chemical carcinogen and human cancer.

  20. Hotspot or Heatwave? Getting to Grips with Neutron Star Burst Oscillations

    NASA Technical Reports Server (NTRS)

    Watts, A.

    2005-01-01

    Many accreting neutron stars, including two of the millisecond pulsars, exhibit high frequency oscillations during Type I X-ray bursts. The properties of the burst oscillations reflect the nature of the thermal asymmetry on the stellar surface. The mechanism that gives rise to the aspzetry, however , remains unclear: possibilities include a hotspot due to uneven fuel distribution, modes of oscillation in the surface layers of the neutron star, or vortices driven by the Coriolis force. I will review some of the latest theory and observations, and present the results of a recent study of variability in the burst oscillations of the millisecond pulsar 51814-338.

  1. Recent hotspot volcanism on Venus from VIRTIS emissivity data.

    PubMed

    Smrekar, Suzanne E; Stofan, Ellen R; Mueller, Nils; Treiman, Allan; Elkins-Tanton, Linda; Helbert, Joern; Piccioni, Giuseppe; Drossart, Pierre

    2010-04-30

    The questions of whether Venus is geologically active and how the planet has resurfaced over the past billion years have major implications for interior dynamics and climate change. Nine "hotspots"--areas analogous to Hawaii, with volcanism, broad topographic rises, and large positive gravity anomalies suggesting mantle plumes at depth--have been identified as possibly active. This study used variations in the thermal emissivity of the surface observed by the Visible and Infrared Thermal Imaging Spectrometer on the European Space Agency's Venus Express spacecraft to identify compositional differences in lava flows at three hotspots. The anomalies are interpreted as a lack of surface weathering. We estimate the flows to be younger than 2.5 million years and probably much younger, about 250,000 years or less, indicating that Venus is actively resurfacing. PMID:20378775

  2. The prevalence of toxic hotspots in former Soviet countries.

    PubMed

    Sharov, Petr; Dowling, Russell; Gogishvili, Megi; Jones, Barbara; Caravanos, Jack; McCartor, Andrew; Kashdan, Zachary; Fuller, Richard

    2016-04-01

    Using a global database of contaminated sites, toxic hotspots in eight former Soviet countries were analyzed to identify the prevalence, types and sources of toxic pollution, as well as their associated potential public health impacts. For this analysis, polluted sites in Armenia, Azerbaijan, Kazakhstan, Kyrgyzstan, Russia, Tajikistan, Ukraine, and Uzbekistan were compiled and analyzed. The levels of contamination of seven key pollutants were assessed in each country. 424 contaminated sites were identified using data from Blacksmith Institute. Pesticides, lead (Pb), radioactive metals, arsenic (As), mercury (Hg), chromium (Cr), and cadmium (Cd) were the most commonly identified key pollutants. Collectively, these sites pose health risks to an estimated 6.2 million residents. The existing data on toxic hotspots in former Soviet countries likely captures only a small percentage of actual contaminated sites, but suggests potentially severe public health consequences. Additional assessments are needed to understand the risks posed by toxic pollution in the region. PMID:26796744

  3. Detecting Hotspots from Taxi Trajectory Data Using Spatial Cluster Analysis

    NASA Astrophysics Data System (ADS)

    Zhao, P. X.; Qin, K.; Zhou, Q.; Liu, C. K.; Chen, Y. X.

    2015-07-01

    A method of trajectory clustering based on decision graph and data field is proposed in this paper. The method utilizes data field to describe spatial distribution of trajectory points, and uses decision graph to discover cluster centres. It can automatically determine cluster parameters and is suitable to trajectory clustering. The method is applied to trajectory clustering on taxi trajectory data, which are on the holiday (May 1st, 2014), weekday (Wednesday, May 7th, 2014) and weekend (Saturday, May 10th, 2014) respectively, in Wuhan City, China. The hotspots in four hours (8:00-9:00, 12:00-13:00, 18:00-19:00 and 23:00-24:00) for three days are discovered and visualized in heat maps. In the future, we will further research the spatiotemporal distribution and laws of these hotspots, and use more data to carry out the experiments.

  4. Galapagos and Easter: A Tale of Two Hotspots

    NASA Astrophysics Data System (ADS)

    Harpp, K.; Hall, P. S.; Jackson, M. G.

    2012-12-01

    Spatial asymmetry in the isotopic composition of volcanic rocks has been identified at several Pacific hotspots, including Hawaii, the Marquesas, and Samoa (Weis, 2011; Huang et al., 2011); the volcanoes are arranged in two chains that define distinct, sub-parallel fields in isotopic space. For these hotspots, lavas from the northern chains have a more depleted signature (higher ɛNd, lower 87Sr/86Sr, lower 208Pb*/206Pb*) than the corresponding southern chains. All 3 hotspots are located near the northern margin of the Large Low Shear Velocity Province (LLSVP) beneath the Pacific. Previous workers have proposed that the asymmetry may reflect bilateral compositional zonation in the plume created by an azimuthal distribution of heterogeneities about the base of the plume conduit, related to material in the LLSVP. This distribution is preserved in filaments from the lower mantle (e.g., Farnetani and Hofmann, 2009). Recently, Payne et al. (in press) showed that rocks from the Societies have an isotopic asymmetry that is the mirror image of Hawaii, with the northern lavas enriched relative to the southern chain. This is consistent with the Societies hotspot's location near the southern, rather than the northern margin of the LLSVP. We present data from two additional hotspots that exhibit spatial asymmetry in the isotopic characteristics of their lavas: the Galapagos and Easter hotspots, both on the Nazca Plate. Despite lacking two distinct volcanic chains, Galapagos lavas define a pattern similar to Hawaii, with enriched isotopic signatures in the southern and western archipelago and more depleted material in the north and east; the boundary dividing the compositional fields defines a NW-SE line parallel to the edge of the LLSVP. In contrast, the Easter Island chain resembles the Societies, in that the enriched lavas are erupted from the northern volcanoes, a mirror image of the Galapagos and coincident with the southern boundary of the LLSVP. Several important

  5. The Yellowstone hotspot, Greater Yellowstone ecosystem, and human geography

    USGS Publications Warehouse

    Pierce, Kenneth L.; Despain, D.G.; Morgan, Lisa A.; Good, John M.

    2007-01-01

    Modern and Pleistocene climate and associated vegetation patterns strongly relate to the topography created by the hotspot and its track along the eastern Snake River Plain. Winter air masses from the moist northern Pacific Ocean traverse the topographic low of the Snake River Plain to where orographic rise onto the Yellowstone Plateau and adjacent mountains produces deep snow. A winter precipitation shadow forms on the lee (eastern) sides of the GYE. During Pleistocene glacial times, this moisture conduit provided by the hotspot-track-produced ice-age glaciers that covered the core of the present GYE. These glaciers sculpted bedrock and produced glacial moraines that are both forested and unforested, sand and gravel of ice-marginal streams and outwash gravels that are commonly covered with sagebrush-grassland, and silty lake sediments that are commonly covered by lush grassland

  6. Identification of Protein–Excipient Interaction Hotspots Using Computational Approaches

    PubMed Central

    Barata, Teresa S.; Zhang, Cheng; Dalby, Paul A.; Brocchini, Steve; Zloh, Mire

    2016-01-01

    Protein formulation development relies on the selection of excipients that inhibit protein–protein interactions preventing aggregation. Empirical strategies involve screening many excipient and buffer combinations using force degradation studies. Such methods do not readily provide information on intermolecular interactions responsible for the protective effects of excipients. This study describes a molecular docking approach to screen and rank interactions allowing for the identification of protein–excipient hotspots to aid in the selection of excipients to be experimentally screened. Previously published work with Drosophila Su(dx) was used to develop and validate the computational methodology, which was then used to determine the formulation hotspots for Fab A33. Commonly used excipients were examined and compared to the regions in Fab A33 prone to protein–protein interactions that could lead to aggregation. This approach could provide information on a molecular level about the protective interactions of excipients in protein formulations to aid the more rational development of future formulations. PMID:27258262

  7. Radiation measurements in low Earth orbit: U.S. and Russian results

    NASA Technical Reports Server (NTRS)

    Badhwar, G. D.

    2000-01-01

    The radiation environment in low-Earth orbital flights is complex. It is strongly influenced by altitude, orbital inclination, time within a given solar cycle, flight duration, and shielding configuration. At any specified shielded location, both primary and secondary particles generated by nuclear interactions of primary particles with spacecraft structure are present. In addition, there are atmospheric secondary albedo protons and neutrons. No single detector can adequately measure this complex radiation field, and measurements of very high linear energy transfer target fragmentation products are particularly difficult. Crew radiation exposure have exclusively been measured using passive thermoluminescent detectors (TLDs). The cosmonaut exposures on the Mir station, uncorrected for the TLD inefficiency and neutron contribution, have varied from a low of 2.43 cGy to a high of 8.70 cGy. These correspond to dose rates of 144 microGy d(-1) to 468 microGy d(-1). These are consistent with rates observed by the D2 ion-chamber. Using the rates measured by the D1 chamber, dose rates under 4 cm of water vary from about 60 microGy d-1 to about 350 microGy d(-1). There is variation of about a factor of two between the dose rates at various locations in the same module. There is also a variation of dose rates of about a factor two between various modules. The highest astronaut dose for a Shuttle flight (STS-82) was 3.205 cGy with a dose rate of 3,221 microGy d(-1). Neutron contribution could be 36 +/- 15% of the astronaut charged particle dose equivalent. East-West asymmetry of dose rate is significant for spacecrafts that fly in an fixed altitude, such as the International Space Station.

  8. Patient radiation doses in the most common interventional cardiology procedures in Croatia: first results.

    PubMed

    Brnić, Z; Krpan, T; Faj, D; Kubelka, D; Ramac, J Popić; Posedel, D; Steiner, R; Vidjak, V; Brnić, V; Visković, K; Baraban, V

    2010-02-01

    Apart from its benefits, the interventional cardiology (IC) is known to generate high radiation doses to patients and medical staff involved. The European Union Medical Exposures Directive 97/43/Euroatom strongly recommend patient dosimetry in interventional radiology, including IC. IC patient radiation doses in four representative IC rooms in Croatia were investigated. Setting reference levels for these procedures have difficulties due to the large difference in procedure complexity. Nevertheless, it is important that some guideline values are available as a benchmark to guide the operators during these potentially high-dose procedures. Local and national diagnostic reference levels (DRLs) were proposed as a guidance. A total of 138 diagnostic (coronary angiography, CA) and 151 therapeutic (PTCA, stenting) procedures were included. Patient irradiation was measured in terms of kerma-area product (KAP), fluoroscopy time (FT) and number of cine-frames (F). KAP was recorded using calibrated KAP-meters. DRLs of KAP, FT and F were calculated as third quartile values rounded up to the integer. Skin doses were assessed on a selected sample of high skin dose procedures, using radiochromic films, and peak skin doses (PSD) were presented. A relative large range of doses in IC was detected. National DRLs were proposed as follows: 32 Gy cm(2), 6.6 min and 610 frames for CA and 72 Gy cm(2), 19 min and 1270 frames for PTCA. PSD <1 Gy were measured in 72 % and PSD >2 Gy in 8 % of selected patients. Measuring the patient doses in radiological procedures is required by law, but rarely implemented in Croatia. The doses recorded in the study are acceptable when compared with the literature, but optimisation is possible. The preliminary DRL values proposed may be used as a guideline for local departments, and should be a basis for radiation reduction measures and quality assurance programmes in IC in Croatia. PMID:19880413

  9. Radiation measurements in low Earth orbit: U.S. and Russian results.

    PubMed

    Badhwar, G D

    2000-11-01

    The radiation environment in low-Earth orbital flights is complex. It is strongly influenced by altitude, orbital inclination, time within a given solar cycle, flight duration, and shielding configuration. At any specified shielded location, both primary and secondary particles generated by nuclear interactions of primary particles with spacecraft structure are present. In addition, there are atmospheric secondary albedo protons and neutrons. No single detector can adequately measure this complex radiation field, and measurements of very high linear energy transfer target fragmentation products are particularly difficult. Crew radiation exposure have exclusively been measured using passive thermoluminescent detectors (TLDs). The cosmonaut exposures on the Mir station, uncorrected for the TLD inefficiency and neutron contribution, have varied from a low of 2.43 cGy to a high of 8.70 cGy. These correspond to dose rates of 144 microGy d(-1) to 468 microGy d(-1). These are consistent with rates observed by the D2 ion-chamber. Using the rates measured by the D1 chamber, dose rates under 4 cm of water vary from about 60 microGy d-1 to about 350 microGy d(-1). There is variation of about a factor of two between the dose rates at various locations in the same module. There is also a variation of dose rates of about a factor two between various modules. The highest astronaut dose for a Shuttle flight (STS-82) was 3.205 cGy with a dose rate of 3,221 microGy d(-1). Neutron contribution could be 36 +/- 15% of the astronaut charged particle dose equivalent. East-West asymmetry of dose rate is significant for spacecrafts that fly in an fixed altitude, such as the International Space Station. PMID:11045524

  10. Some Analytic Results for the Study of Broadband Noise Radiation from Wings, Propellers and Jets in Uniform Motion

    NASA Technical Reports Server (NTRS)

    Farassat, F.; Casper, J.

    2003-01-01

    Alan Powell has made significant contributions to the understanding of many aeroacoustic problems, in particular, the problems of broadband noise from jets and boundary layers. In this paper, some analytic results are presented for the calculation of the correlation function of the broadband noise radiated from a wing, a propeller, and a jet in uniform forward motion. It is shown that, when the observer (or microphone) motion is suitably chosen, the geometric terms of the radiation formula become time independent. The time independence of these terms leads to a significant simplification of the statistical analysis of the radiated noise, even when the near field terms are included. For a wing in forward motion, if the observer is in the moving reference frame, then the correlation function of the near and far field noise can be related to a space-time cross-correlation function of the pressure on the wing surface. A similar result holds for a propeller in forward flight if the observer is in a reference frame that is attached to the propeller and rotates at the shaft speed. For a jet in motion, it is shown that the correlation function of the radiated noise can be related to the space-time crosscorrelation of the Lighthill stress tensor in the jet. Exact analytical results are derived for all three cases. For the cases under present consideration, the inclusion of the near field terms does not introduce additional complexity, as compared to existing formulations that are limited to the far field.

  11. Initial Results from the Radiation Dosimetry Experiment (RaD-X) Balloon Flight Mission

    NASA Technical Reports Server (NTRS)

    Mertens, Christopher J.

    2015-01-01

    The NASA Radiation Dosimetry Experiment (RaD-X) high-altitude balloon mission was successfully launched from Fort Sumner, New Mexico USA on 25 September, 2015. Over 15 hours of science data were obtained from four dosimeters at altitudes above about 25 km. The four dosimeters flown on the RaD-X science payload are a Hawk version 3.0 Tissue Equivalent Proportional Counter (TEPC) manufactured by Far West Technologies, a Liulin dosimeter-spectrometer produced by the Solar Research and Technology Institute, Bulgarian Academy of Sciences, a total ionizing dose detector manufactured by Teledyne Microelectronic Technologies, and the RaySure detector provided by the University of Surrey.

  12. Saturnian trapped radiation and its absorption by satellites and rings: the first results from Pioneer 11

    SciTech Connect

    Simpson, J.A.; Bastian, T.S.; Chenette, D.L.; Lentz, G.A.; McKibben, R.B.; Pyle, K.R.; Tuzzolino, A.J.

    1980-01-25

    Electrons and protons accelerated and trapped in a Saturnian magnetic field were found by the University of Chicago experiments on Pioneer 11 within 20 Saturn radii (R/sub S/) of the planet. In the innermost regions, strong absorption effects due to satellites and ring material were observed, and from approx.4 R/sub S/ inwards to the outer edge of the A ring at 2.30 R/sub S/ (where the radiation is absorbed), the intensity distributions of protons (greater than or equal to 0.5 million electron volts) and electrons (2 to 20 million electron volts) were axially symmetric, consistent with a centered dipole aligned with the planetary rotation axis. The maximum fluxes observed for protons (> 35 million electron volts and for electrons > 3.4 million electron volts) were 3 x 10/sup 4/ and 3 x 10/sup 6/ per square centimeter per second, respectively. Absorption of radiation by Mimas provides a means of estimating the radial diffusion coefficient for charged particle transport. However, the rapid flux increases observed between absorption features raise new questions concerning the physics of charged-particle transport and acceleration. An absorption feature 2.5 R/sub S/ has led to the discovery of a previously unknown satellite with a diameter of greater than or equal to 200 kilometers, semimajor axis of 2.51 R/sub S/, and eccentricity of 0.013. Radiation absorption features that suggest a nonuniform distribution of matter around Saturn have also been found from 2.34 to 2.36 R/sub S/, near the position of the F ring discovered by the Pioneer imaging experiment. Beneath the A, B, and C rings a low flux of high-energy electrons was observed. It is concluded that the inner Saturn magnetosphere, because of its near-axial symmetry and the many discrete radiation absorption regions, offers a unique opportunity to study the acceleration and transport of charged particles in a planetary magnetic field. 5 figures, 2 tables

  13. New results on radiative J/psi decays from MARK III at SPEAR

    SciTech Connect

    Wermes, N.

    1984-04-01

    Selected topics on radiative decays of the J/psi from MARK III at SPEAR are presented. These topics include the decay J/psi ..-->.. ..gamma..K anti K where the final state resonances f'(1515), theta(1700) and xi(2200) have been analyzed. The decay J/psi ..-->.. (..gamma.. vector vector) is presented in three final states, J/psi ..-->.. ..gamma.. phi phi, ..gamma.. rho rho and ..gamma omega omega.., providing the first measurement of the eta/sub c/ spin-parity (in ..gamma.. phi phi) and evidence for structures (in ..gamma.. rho rho and ..gamma omega omega..) near 1.7 GeV. 24 references.

  14. Results of using low-intensity laser radiation for plumbum intoxication

    NASA Astrophysics Data System (ADS)

    Dejneka, S. Y.

    1999-11-01

    We have studied the noninvasive effect of low-intensive laser impulse radiation in the infrared spectrum region on the liver projection site in experimental lead intoxication achieved by means of intragastric administration of Pb acetate to albino rats over a period of 30 days in a dose of 30 mg/kg. We determined a number of indices in laboratory animals which characterized the state of the nervous system, immune system, muscular performance efficiency. We have also investigated the hematologic indices and the blood and urinary delta-aminolevulinic acid content as well as the plumbum levels in the blood, urine and the animals' inner organs.

  15. An Examination of the Relationship between Hotspots and Recombination Associated with Chromosome 21 Nondisjunction

    PubMed Central

    Tinker, Stuart W.; Allen, Emily Graves; Bean, Lora J. H.; Begum, Ferdouse; Feingold, Eleanor; Chowdhury, Reshmi; Cheung, Vivian; Sherman, Stephanie L.

    2014-01-01

    Trisomy 21, resulting in Down Syndrome (DS), is the most common autosomal trisomy among live-born infants and is caused mainly by nondisjunction of chromosome 21 within oocytes. Risk factors for nondisjunction depend on the parental origin and type of meiotic error. For errors in the oocyte, increased maternal age and altered patterns of recombination are highly associated with nondisjunction. Studies of normal meiotic events in humans have shown that recombination clusters in regions referred to as hotspots. In addition, GC content, CpG fraction, Poly(A)/Poly(T) fraction and gene density have been found to be significant predictors of the placement of sex-averaged recombination in the human genome. These observations led us to ask whether the altered patterns of recombination associated with maternal nondisjunction of chromosome 21 could be explained by differences in the relationship between recombination placement and recombination-related genomic features (i.e., GC content, CpG fraction, Poly(A)/Poly(T) fraction or gene density) on 21q or differential hot-spot usage along the nondisjoined chromosome 21. We found several significant associations between our genomic features of interest and recombination, interestingly, these results were not consistent among recombination types (single and double proximal or distal events). We also found statistically significant relationships between the frequency of hotspots and the distribution of recombination along nondisjoined chromosomes. Collectively, these findings suggest that factors that affect the accessibility of a specific chromosome region to recombination may be altered in at least a proportion of oocytes with MI and MII errors. PMID:24926858

  16. Radiative forcing associated with particulate carbon emissions resulting from the use of mercury control technology.

    PubMed

    Lin, Guangxing; Penner, Joyce E; Clack, Herek L

    2014-09-01

    Injection of powdered activated carbon (PAC) adsorbents into the flue gas of coal fired power plants with electrostatic precipitators (ESPs) is the most mature technology to control mercury emissions for coal combustion. However, the PAC itself can penetrate ESPs to emit into the atmosphere. These emitted PACs have similar size and optical properties to submicron black carbon (BC) and thus could increase BC radiative forcing unintentionally. The present paper estimates, for the first time, the potential emission of PAC together with their climate forcing. The global average maximum potential emissions of PAC is 98.4 Gg/yr for the year 2030, arising from the assumed adoption of the maximum potential PAC injection technology, the minimum collection efficiency, and the maximum PAC injection rate. These emissions cause a global warming of 2.10 mW m(-2) at the top of atmosphere and a cooling of -2.96 mW m(-2) at the surface. This warming represents about 2% of the warming that is caused by BC from direct fossil fuel burning and 0.86% of the warming associated with CO2 emissions from coal burning in power plants. Its warming is 8 times more efficient than the emitted CO2 as measured by the 20-year-integrated radiative forcing per unit of carbon input (the 20-year Global Warming Potential). PMID:25093939

  17. Delivery of intraoperative radiation therapy after pneumonectomy: experimental observations and early clinical results

    SciTech Connect

    Pass, H.I.; Sindelar, W.F.; Kinsella, T.J.; DeLuca, A.M.; Barnes, M.; Kurtzman, S.; Hoekstra, H.; Tochner, Z.; Roth, J.; Glatstein, E.

    1987-07-01

    Intraoperative radiation therapy (IORT) is capable of delivering high doses of radiation to mediastinal structures while sparing lung parenchyma, heart, and other locoregional tissues. A canine model of pulmonary resection and IORT was investigated by performing a pneumonectomy in 15 adult foxhounds followed by 0 cGy, 2000 cGy, 3000 cGy, 4000 cGy. No clinical complications developed in 4 animals in the 2000-cGy group. However, 2 of the 8 animals given a high dose died of esophageal hemorrhage or carinal necrosis. Esophagitis occurred in 10 of 12 animals, and none of the animals experienced bronchial stump dehiscence. In a limited Phase I protocol, 4 patients with non-small cell lung cancer were treated with resection and 2500 cGy of IORT to two separate ports encompassing the superior and inferior mediastinum. Two patients experienced life-threatening bronchopleural fistulas, and 2 patients died as a consequence of esophageal problems. One patients had recurrence with brain metastases, and the 1 long-term survivor is free from disease. As opposed to the animal model of thoracic IORT, the clinical study demonstrated major toxicity with respiratory and esophageal morbidity. The therapeutic usefulness of thoracic IORT in the management of lung cancer must be questioned in view of this small but consistent series of patients. Further carefully designed clinical studies using lower doses of IORT are needed.

  18. Pan-Cancer Analysis of Mutation Hotspots in Protein Domains.

    PubMed

    Miller, Martin L; Reznik, Ed; Gauthier, Nicholas P; Aksoy, Bülent Arman; Korkut, Anil; Gao, Jianjiong; Ciriello, Giovanni; Schultz, Nikolaus; Sander, Chris

    2015-09-23

    In cancer genomics, recurrence of mutations in independent tumor samples is a strong indicator of functional impact. However, rare functional mutations can escape detection by recurrence analysis owing to lack of statistical power. We enhance statistical power by extending the notion of recurrence of mutations from single genes to gene families that share homologous protein domains. Domain mutation analysis also sharpens the functional interpretation of the impact of mutations, as domains more succinctly embody function than entire genes. By mapping mutations in 22 different tumor types to equivalent positions in multiple sequence alignments of domains, we confirm well-known functional mutation hotspots, identify uncharacterized rare variants in one gene that are equivalent to well-characterized mutations in another gene, detect previously unknown mutation hotspots, and provide hypotheses about molecular mechanisms and downstream effects of domain mutations. With the rapid expansion of cancer genomics projects, protein domain hotspot analysis will likely provide many more leads linking mutations in proteins to the cancer phenotype. PMID:27135912

  19. Imaging of primary and secondary radiation-Modelling and experimental results of a radioactive source and a water phantom

    NASA Astrophysics Data System (ADS)

    Gamage, K. A. A.; Taylor, G. C.; Joyce, M. J.

    2014-11-01

    In this paper the contribution of primary and secondary radiation from a water phantom to a pinhole volume, as a result of three neutron sources (Cf, AmBe and 5 MeV mono-energetic) and two gamma sources (Cs and Co), is separately estimated using the PTRAC particle tracking option available in MCNP. Also in this paper imaging of the mixed radiation field produced by a Van de Graaf accelerator (when a water phantom is present) is described. In the model, a spherical tally volume, 2 cm in diameter, was placed equidistantly from a radioactive source and 30×30×15 cm3 water phantom. Monte Carlo simulations have been carried out to investigate the level of primary and secondary radiation contributing to the pinhole volume directly from the source and from interactions in the phantom respectively. The spatial distribution of counts clearly discriminated the source and the phantom. The results have shown that the percentage of neutrons reflected from the phantom with energies above 1 MeV increases with mean energy of the source. This method has significant potential to characterise secondary radiation in proton therapy, where it would help to verify the location and the energy delivered during the treatment.

  20. Identifying modeled ship noise hotspots for marine mammals of Canada's Pacific region.

    PubMed

    Erbe, Christine; Williams, Rob; Sandilands, Doug; Ashe, Erin

    2014-01-01

    The inshore, continental shelf waters of British Columbia (BC), Canada are busy with ship traffic. South coast waters are heavily trafficked by ships using the ports of Vancouver and Seattle. North coast waters are less busy, but expected to get busier based on proposals for container port and liquefied natural gas development and expansion. Abundance estimates and density surface maps are available for 10 commonly seen marine mammals, including northern resident killer whales, fin whales, humpback whales, and other species with at-risk status under Canadian legislation. Ship noise is the dominant anthropogenic contributor to the marine soundscape of BC, and it is chronic. Underwater noise is now being considered in habitat quality assessments in some countries and in marine spatial planning. We modeled the propagation of underwater noise from ships and weighted the received levels by species-specific audiograms. We overlaid the audiogram-weighted maps of ship audibility with animal density maps. The result is a series of so-called "hotspot" maps of ship noise for all 10 marine mammal species, based on cumulative ship noise energy and average distribution in the boreal summer. South coast waters (Juan de Fuca and Haro Straits) are hotspots for all species that use the area, irrespective of their hearing sensitivity, simply due to ubiquitous ship traffic. Secondary hotspots were found on the central and north coasts (Johnstone Strait and the region around Prince Rupert). These maps can identify where anthropogenic noise is predicted to have above-average impact on species-specific habitat, and where mitigation measures may be most effective. This approach can guide effective mitigation without requiring fleet-wide modification in sites where no animals are present or where the area is used by species that are relatively insensitive to ship noise. PMID:24598866

  1. Hotspots in ground and surface water carbon fluxes through a freshwater to marine (mangrove) transition zone

    NASA Astrophysics Data System (ADS)

    Larsen, J.; Welti, N.; Hayes, M.; Lockington, D. A.

    2014-12-01

    The transfer of carbon and water from coastal freshwater wetlands to intertidal and marine zones is significant for sustaining ecosystem processes, particularly within mangroves environments. Large increases in carbon and nutrient fluxes within spatially confined zones (hotspots) are significant as drivers for broader cycling. How these processes relate to the transfers between surface and groundwater systems, as well as the transition from freshwater to marine environments, remains poorly understood. We investigated the flux of carbon and water from a freshwater wetland, to a saltmarsh and then mangroves, both within the main surface channel and within a comprehensive shallow groundwater bore network. We were able to characterise the main spatial trends in water gradients and mixing (using salinity, hydraulic gradients, stable water isotopes, and temperature) over seasonal cycles. In addition, at the same time we investigated the changes in dissolved organic carbon concentration and quality (fluorescence, UV), as well as nutrients (NO3, NH4). This revealed the river and tidal channel to be a significant export pathway for organic carbon, which was generally highly aromatic and recalcitrant. However, we also found that isolated sections of the brackish groundwater mixing zone between freshwater and marine provided a consistently high DOC 'hotspot' of very high quality carbon. This hotspot has high lateral groundwater gradients and therefore likely transports this carbon to the rest of the mangrove subsurface, where it is rapidly assimilated. These results imply large spatial heterogeneity in the carbon cycling between freshwater and marine environments, and have significant implications for the processing of the organic matter, and therefore also the respiration of greenhouse gases such as CO2 and CH4.

  2. Biodiversity and paleobiogeography of the European freshwater Neogene: trends, hotspots and faunal turnovers

    NASA Astrophysics Data System (ADS)

    Neubauer, Thomas A.; Harzhauser, Mathias; Georgopoulou, Elisavet; Andreas, Kroh; Mandic, Oleg

    2015-04-01

    We present an outline of a paleobiogeographic framework for the European fresh- and brackish-water systems during the Neogene. Data basis is a presence-absence matrix of lacustrine gastropods from over 2,700 localities. Cluster analyses were separately carried out on the datasets of the four time slices Early Miocene, Middle Miocene, Late Miocene, and Pliocene. Based on the results of the cluster analyses, the degree of endemicity, and geographical coherence, we classified the lake systems of the four time intervals into biogeographic units. The increasing degree of provincialism throughout the Neogene supported more detailed breakdowns in younger intervals. This pattern reflects the ongoing continentalization of Europe linked to the Alpidic Orogenesis. Additionally, the retreat of the Paratethys Sea and its isolation from the Mediterranean promoted the evolution of endemic faunas in surrounding lacustrine systems. Direct descendants such as long-lived Lake Pannon, Lake Dacia or Lake Slavonia persisted over several millions of years and promoted the evolution of highly diverse and endemic faunas. Because of their extensive duration they crucially influenced family-level composition, differences of the relative species richnesses per biogeographic unit, and rising rate of endemicity. We show that the biogeographic classification as well as the existence of biodiversity hotspots are tightly linked to the formation and evolution of long-lived lacustrine environments and thus to Europe's geodynamic history. Heat maps are provided to visualize the shifting distributions of hotspots through time. The only physiographic factor that can be shown to be correlated with species richness is the size of a lake. Other factors such as latitude, longitude or temporal duration show weak relationships. Correlation of biodiversity trends to climatic parameters such as temperature and precipitation are feasible only for selected periods. Climate is considered to have only minor

  3. Conservation planning in agricultural landscapes: hotspots of conflict between agriculture and nature

    PubMed Central

    Shackelford, Gorm E; Steward, Peter R; German, Richard N; Sait, Steven M; Benton, Tim G

    2015-01-01

    Aim Conservation conflict takes place where food production imposes a cost on wildlife conservation and vice versa. Where does conservation impose the maximum cost on production, by opposing the intensification and expansion of farmland? Where does conservation confer the maximum benefit on wildlife, by buffering and connecting protected areas with a habitable and permeable matrix of crop and non-crop habitat? Our aim was to map the costs and benefits of conservation versus production and thus to propose a conceptual framework for systematic conservation planning in agricultural landscapes. Location World-wide. Methods To quantify these costs and benefits, we used a geographic information system to sample the cropland of the world and map the proportion of non-crop habitat surrounding the cropland, the number of threatened vertebrates with potential to live in or move through the matrix and the yield gap of the cropland. We defined the potential for different types of conservation conflict in terms of interactions between habitat and yield (potential for expansion, intensification, both or neither). We used spatial scan statistics to find ‘hotspots’ of conservation conflict. Results All of the ‘hottest’ hotspots of conservation conflict were in sub-Saharan Africa, which could have impacts on sustainable intensification in this region. Main conclusions Systematic conservation planning could and should be used to identify hotspots of conservation conflict in agricultural landscapes, at multiple scales. The debate between ‘land sharing’ (extensive agriculture that is wildlife friendly) and ‘land sparing’ (intensive agriculture that is less wildlife friendly but also less extensive) could be resolved if sharing and sparing were used as different types of tool for resolving different types of conservation conflict (buffering and connecting protected areas by maintaining matrix quality, in different types of matrix). Therefore, both sharing and sparing

  4. Recombining without Hotspots: A Comprehensive Evolutionary Portrait of Recombination in Two Closely Related Species of Drosophila

    PubMed Central

    Smukowski Heil, Caiti S.; Ellison, Chris; Dubin, Matthew; Noor, Mohamed A.F.

    2015-01-01

    Meiotic recombination rate varies across the genome within and between individuals, populations, and species in virtually all taxa studied. In almost every species, this variation takes the form of discrete recombination hotspots, determined in some mammals by a protein called PRDM9. Hotspots and their determinants have a profound effect on the genomic landscape, and share certain features that extend across the tree of life. Drosophila, in contrast, are anomalous in their absence of hotspots, PRDM9, and other species-specific differences in the determination of recombination. To better understand the evolution of meiosis and general patterns of recombination across diverse taxa, we present a truly comprehensive portrait of recombination across time, combining recently published cross-based contemporary recombination estimates from each of two sister species with newly obtained linkage-disequilibrium-based historic estimates of recombination from both of these species. Using Drosophila pseudoobscura and Drosophila miranda as a model system, we compare recombination rate between species at multiple scales, and we suggest that Drosophila replicate the pattern seen in human–chimpanzee in which recombination rate is conserved at broad scales. We also find evidence of a species-wide recombination modifier(s), resulting in both a present and historic genome-wide elevation of recombination rates in D. miranda, and identify broad scale effects on recombination from the presence of an inversion. Finally, we reveal an unprecedented view of the distribution of recombination in D. pseudoobscura, illustrating patterns of linked selection and where recombination is taking place. Overall, by combining these estimation approaches, we highlight key similarities and differences in recombination between Drosophila and other organisms. PMID:26430062

  5. Wide-angle Seismic Constraints On The Evolution of Galapagos Hotspot - Cocos Nazca Spreading Center Interaction

    NASA Astrophysics Data System (ADS)

    Sallares, V.; Charvis, Ph.; Flueh, E. R.; Bialas, J.; Walther, C.

    The Nazca and Cocos plates include several blocks of thickened oceanci crust thought to have originated from the interaction between the Galapagos hotspot and the Cocos- Nazca spreading center during the last 20 Ma. The most prominent are the Cocos, Malpelo, and Carnegie Ridges. In this work we compare the crustal seismic structure of these ridges along five wide-angle profiles acquired during the PAGANINI-1999 and SALIERI-2001 experiments. Two of these profiles are located on the Cocos Ridge and another one in Malpelo. The last two profiles (Carnegie Ridge) are in the conjugate positions with Malpelo (at~20 Ma) and southern Cocos (at~12 Ma). The results show that maximum crustal thickness along these profiles is highly vari- able, ranging from 19-20 km in northern Cocos, Malpelo, and its conjugate position, to 16.5 km in southern Cocos and only 13 km in its conjugate position. Oceanic Layer 2 thickness is quite uniform regardless of total crustal thickness variations, and thus crustal thickening is mainly accomodated in Layer 3. The mean seismic velocities of Layer 3 are similar in all profiles, and generally lower where the crust is the thick- est. This leads to an overall anticorrelation between crustal thickness and bulk lower crustal velocities. These observations suggest, on one hand, the existence of important variations on the Galapagos hotspot activity and on its relative location with respect to the spreading center. At 20 Ma, the hotspot-ridge system would be dominated by a vig- orous on-ridge magmatic activity, while at 12 Ma it would show a significantly lower, off-ridge centered activity. On the other hand, the obtained velocity-thickness rela- tionship differs from that expected for a crust generated by decompression melting of an abnormally hot mantle. We suggest that other parameters such as active upwelling, or variations in water content and/or composition of the mantle source must be taken into account.

  6. Critical Evaluation of Radiometric Ages Used for Tracking Hotspots in the Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Baksi, A. K.

    2004-12-01

    fail the statistical test of reliability; many steps show high levels of atmospheric argon - the samples are (badly) altered. (4) A set of papers (e.g. Gripp and Gordon, 2002, Geophys. J. Int., young hotspot tracks; Duncan, 1985 - New Hebrides-Samoa lineament) make use of K-Ar dates, wholly or in the main. These dates should be treated as minimum estimates of the crystallization age. (5) A final set of papers (Sager et al., 1993, AGU Monograph 77, Japanese and Marcus-Wake Seamounts; Lincoln et al., 1993, AGU Monograph 77, Marshall Islands), quote ages without listing the relevant analytical data. These results are to be treated as suspect, and not used for quantitative tracking of hotspot trails. In conclusion, the purported progression of ages for numerous hotspot tracks in the Pacific Ocean does not withstand critical scrutiny.

  7. Correlates of Injecting in an HIV Incidence Hotspot among Substance Users in Tijuana, Mexico

    PubMed Central

    Kori, Nana; Roth, Alexis M.; Lozada, Remedios; Vera, Alicia; Brouwer, Kimberly C.

    2015-01-01

    Background Substance use and HIV are growing problems in the Mexico-U.S. border city of Tijuana, a sex tourism destination situated on a northbound drug trafficking route. In a previous longitudinal study of injection drug users (IDUs), we found that >90% of incident HIV cases occurred within an ‘HIV incidence hotspot,’ consisting of 2.5-blocks. This study examines behavioral, social, and environmental correlates associated with injecting in this HIV hotspot. Methods From 4/06–6/07, IDUs aged ≥18 years were recruited using respondent-driven sampling. Participants underwent antibody testing for HIV and syphilis and interviewer-administered surveys eliciting information on demographics, drug use, sexual behaviors, and socio-environmental influences. Participants were defined as injecting in the hotspot if they most frequently injected within a 3 standard deviational ellipse of the cohort’s incident HIV cases. Logistic regression was used to identify individual and structural factors associated with the HIV ‘hotspot’. Results Of 1,031 IDUs, the median age was 36 years; 85% were male; HIV prevalence was 4%. As bivariate analysis indicated different correlates for males and females, models were stratified by sex. Factors independently associated with injecting in the HIV hotspot for male IDUs included homelessness (AOR 1.72; 95%CI 1.14–2.6), greater intra-urban mobility (AOR 3.26; 95% CI 1.67–6.38), deportation (AOR 1.58; 95% CI 1.18–2.12), active syphilis (AOR 3.03; 95%CI 1.63–5.62), needle sharing (AOR 0.57; 95%CI 0.42–0.78), various police interactions, perceived HIV infection risk (AOR 1.52; 95%CI 1.13–2.03), and health insurance status (AOR 0.53; 95%CI 0.33–0.87). For female IDUs, significant factors included sex work (AOR 8.2; 95%CI 2.2–30.59), lifetime syphilis exposure (AOR 2.73; 95%CI 1.08–6.93), injecting inside (AOR 5.26; 95%CI 1.54–17.92), arrests for sterile syringe possession (AOR 4.87; 95%CI 1.56–15.15), prior HIV

  8. Lunar dusty plasma: A result of interaction of the solar wind flux and ultraviolet radiation with the lunar surface

    NASA Astrophysics Data System (ADS)

    Lisin, E. A.; Tarakanov, V. P.; Popel, S. I.; Petrov, O. F.

    2015-11-01

    One of the main problems of future missions to the Moon is associated with lunar dust. Solar wind flux and ultraviolet radiation interact with the lunar surface. As a result, there is a substantial surface change and a near-surface plasma sheath. Dust particles from the lunar regolith, which turned in this plasma because of any mechanical processes, can levitate above the surface, forming dust clouds. In preparing of the space experiments “Luna-Glob” and “Luna-Resource” particle-in-cell calculations of the near-surface plasma sheath parameters are carried out. Here we present some new results of particle-in-cell simulation of the plasma sheath formed near the surface of the moon as a result of interaction of the solar wind and ultraviolet radiation with the lunar surface. The conditions of charging and stable levitation of dust particles in plasma above the lunar surface are also considered.

  9. Missing history (16 71 Ma) of the Galápagos hotspot: Implications for the tectonic and biological evolution of the Americas

    NASA Astrophysics Data System (ADS)

    Hoernle, Kaj; van den Bogaard, Paul; Werner, Reinhard; Lissinna, Britta; Hauff, Folkmar; Alvarado, Guillermo; Garbe-Schönberg, Dieter

    2002-09-01

    We present the results of volcanological, geochemical, and geochronological studies of volcanic rocks from Malpelo Island on the Nazca plate (15.8 17.3 Ma) belonging to the Galápagos hotspot tracks, and igneous complexes (20.8 71.3 Ma) along the Pacific margin of Costa Rica and Panama. The igneous complexes consist of accreted portions of ocean island and seamount volcanoes and aseismic ridges, representing the missing (primarily subducted) history of the Galápagos hotspot. The age and geochemical data directly link the Galápagos hotspot tracks on the Pacific Ocean floor to the Caribbean large igneous province (ca. 72 95 Ma), confirming a Pacific origin for the Caribbean oceanic plateau from the Galápagos hotspot. We propose that emplacement of this oceanic plateau between the Americas and interaction of the Galápagos hotspot tracks with the Central American Arc played a fundamental role in the formation of land bridges between the Americas in Late Cretaceous Paleocene and Pliocene-Holocene time. The land bridges allowed the exchange of terrestrial faunas (e.g., dinosaurs, mastodons, saber-tooth cats, and ground sloths) between the Americas and served as barriers for the exchange of marine organisms between the central Pacific Ocean and the Caribbean Sea and the central Atlantic Ocean.

  10. Preliminary results of radiation measurements from the marine stratus FIRE experiment

    NASA Technical Reports Server (NTRS)

    Valero, Francisco P. J.; Hammer, Philip D.; Ackerman, Thomas P.; Gore, Warren J. Y.; Weil, Melinda L.

    1990-01-01

    During the marine stratocumulus phase of the First International Satellite Cloud Climatology Regional Experiment (FIRE) in July 1987, researchers acquired radiative flux data from a variety of instruments which were flown on the ER-2 high altitude aircraft. The spectral coverage ranged from the near UV to beyond 40 microns. A survey and selected preliminary analyses of these measurements are presented. The specific instruments used in the experiment were chosen primarily for measuring quantities of specific interest for marine stratocumulus fields. However, testing and evaluation of instrumentation and techniques to be used in the future inland cirrus experiment was also an important consideration. Details of the instruments and the significance of what they measure are given.

  11. Space Station heat pipe advanced radiator element (SHARE) flight test results and analysis

    NASA Technical Reports Server (NTRS)

    Kosson, Robert; Brown, Richard; Ungar, Eugene

    1990-01-01

    The SHARE experiment, which consisted of a single 51 ft long by 1 ft wide prototypical Space Station heat pipe radiator panel, was flown aboard STS-29 in March 1989. Several problems were uncovered during the flight which limited performance. Extensive post-flight analysis has revealed that the manifold connecting the evaporator and condenser sections did not prime properly in 0-g, and that a mismatch in hydraulic diameters between the evaporator and condenser caused large bubbles to be present in the liquid channel at startup. These bubbles subsequently became trapped at the evaporator entrance, halting liquid flow and causing premature dryout of the evaporator wall grooves. The experiment did demonstrate heat pipe transport capability of up to 1572 W with near isothermality in both the evaporator and condenser for short periods of time.

  12. Structural health management of aerospace hotspots under fatigue loading

    NASA Astrophysics Data System (ADS)

    Soni, Sunilkumar

    Sustainability and life-cycle assessments of aerospace systems, such as aircraft structures and propulsion systems, represent growing challenges in engineering. Hence, there has been an increasing demand in using structural health monitoring (SHM) techniques for continuous monitoring of these systems in an effort to improve safety and reduce maintenance costs. The current research is part of an ongoing multidisciplinary effort to develop a robust SHM framework resulting in improved models for damage-state awareness and life prediction, and enhancing capability of future aircraft systems. Lug joints, a typical structural hotspot, were chosen as the test article for the current study. The thesis focuses on integrated SHM techniques for damage detection and characterization in lug joints. Piezoelectric wafer sensors (PZTs) are used to generate guided Lamb waves as they can be easily used for onboard applications. Sensor placement in certain regions of a structural component is not feasible due to the inaccessibility of the area to be monitored. Therefore, a virtual sensing concept is introduced to acquire sensor data from finite element (FE) models. A full three dimensional FE analysis of lug joints with piezoelectric transducers, accounting for piezoelectrical-mechanical coupling, was performed in Abaqus and the sensor signals were simulated. These modeled sensors are called virtual sensors. A combination of real data from PZTs and virtual sensing data from FE analysis is used to monitor and detect fatigue damage in aluminum lug joints. Experiments were conducted on lug joints under fatigue loads and sensor signals collected were used to validate the simulated sensor response. An optimal sensor placement methodology for lug joints is developed based on a detection theory framework to maximize the detection rate and minimize the false alarm rate. The placement technique is such that the sensor features can be directly correlated to damage. The technique accounts for a

  13. Results.

    ERIC Educational Resources Information Center

    Zemsky, Robert; Shaman, Susan; Shapiro, Daniel B.

    2001-01-01

    Describes the Collegiate Results Instrument (CRI), which measures a range of collegiate outcomes for alumni 6 years after graduation. The CRI was designed to target alumni from institutions across market segments and assess their values, abilities, work skills, occupations, and pursuit of lifelong learning. (EV)

  14. Infant Brain Tumors: Incidence, Survival, and the Role of Radiation Based on Surveillance, Epidemiology, and End Results (SEER) Data

    SciTech Connect

    Bishop, Andrew J.; McDonald, Mark W.; Chang, Andrew L.; Esiashvili, Natia

    2012-01-01

    Purpose: To evaluate the incidence of infant brain tumors and survival outcomes by disease and treatment variables. Methods and Materials: The Surveillance, Epidemiology, and End Results (SEER) Program November 2008 submission database provided age-adjusted incidence rates and individual case information for primary brain tumors diagnosed between 1973 and 2006 in infants less than 12 months of age. Results: Between 1973 and 1986, the incidence of infant brain tumors increased from 16 to 40 cases per million (CPM), and from 1986 to 2006, the annual incidence rate averaged 35 CPM. Leading histologies by annual incidence in CPM were gliomas (13.8), medulloblastoma and primitive neuroectodermal tumors (6.6), and ependymomas (3.6). The annual incidence was higher in whites than in blacks (35.0 vs. 21.3 CPM). Infants with low-grade gliomas had the highest observed survival, and those with atypical teratoid rhabdoid tumors (ATRTs) or primary rhabdoid tumors of the brain had the lowest. Between 1979 and 1993, the annual rate of cases treated with radiation within the first 4 months from diagnosis declined from 20.5 CPM to <2 CPM. For infants with medulloblastoma, desmoplastic histology and treatment with both surgery and upfront radiation were associated with improved survival, but on multivariate regression, only combined surgery and radiation remained associated with improved survival, with a hazard ratio for death of 0.17 compared with surgery alone (p = 0.005). For ATRTs, those treated with surgery and upfront radiation had a 12-month survival of 100% compared with 24.4% for those treated with surgery alone (p = 0.016). For ependymomas survival was higher in patients treated in more recent decades (p = 0.001). Conclusion: The incidence of infant brain tumors has been stable since 1986. Survival outcomes varied markedly by histology. For infants with medulloblastoma and ATRTs, improved survival was observed in patients treated with both surgery and early radiation

  15. Spatial variations in immediate greenhouse gases and aerosol emissions and resulting radiative forcing from wildfires in interior Alaska

    NASA Astrophysics Data System (ADS)

    Huang, Shengli; Liu, Heping; Dahal, Devendra; Jin, Suming; Li, Shuang; Liu, Shuguang

    2016-02-01

    Boreal fires can cool the climate; however, this conclusion came from individual fires and may not represent the whole story. We hypothesize that the climatic impact of boreal fires depends on local landscape heterogeneity such as burn severity, prefire vegetation type, and soil properties. To test this hypothesis, spatially explicit emission of greenhouse gases (GHGs) and aerosols and their resulting radiative forcing are required as an important and necessary component towards a full assessment. In this study, we integrated remote sensing (Landsat and MODIS) and models (carbon consumption model, emission factors model, and radiative forcing model) to calculate the carbon consumption, GHGs and aerosol emissions, and their radiative forcing of 2001-2010 fires at 30 m resolution in the Yukon River Basin of Alaska. Total carbon consumption showed significant spatial variation, with a mean of 2,615 g C m-2 and a standard deviation of 2,589 g C m-2. The carbon consumption led to different amounts of GHGs and aerosol emissions, ranging from 593.26 Tg (CO2) to 0.16 Tg (N2O). When converted to equivalent CO2 based on global warming potential metric, the maximum 20 years equivalent CO2 was black carbon (713.77 Tg), and the lowest 20 years equivalent CO2 was organic carbon (-583.13 Tg). The resulting radiative forcing also showed significant spatial variation: CO2, CH4, and N2O can cause a 20-year mean radiative forcing of 7.41 W m-2 with a standard deviation of 2.87 W m-2. This emission forcing heterogeneity indicates that different boreal fires have different climatic impacts. When considering the spatial variation of other forcings, such as surface shortwave forcing, we may conclude that some boreal fires, especially boreal deciduous fires, can warm the climate.

  16. Evidence for a Thinned Mantle Transition Zone beneath the Azores Hotspot

    NASA Astrophysics Data System (ADS)

    Schutt, D. L.; Solomon, S. C.; Burkett, P. G.

    2002-12-01

    that seen beneath the Iceland, Hawaii, Galapagos, and Society hotspots. We infer that the transition zone beneath the Azores is anomalously hot, a result consistent with the hypothesis that the Azores hotspot is underlain by a mantle plume.

  17. The Yellowstone Hotspot: Effects on Intraplate Stress and Deformation of the Western U.S

    NASA Astrophysics Data System (ADS)

    Puskas, C. M.; Smith, R. B.

    2009-12-01

    The Yellowstone hotspot and its modeled upper mantle plume is responsible for a topographic swell with 300 m excess elevation over a 700-km wide area and a large geoid anomaly of 12 m above background levels, which in turn dynamically affect the regional stress and deformation field. Time-progressive, silicic volcanism along the Yellowstone-Snake River Plain (YSRP) has contributed to the local stress and deformation fields by altering crustal structure through magmatic underplating, intrusion, and eruption. We have modeled the horizontal deviatoric stress field from variations in lithospheric structure, constrained by the regional velocity field from 2500 GPS observations and Late Quaternary fault slip rates. Receiver functions provided additional information on crustal thickness, allowing lithospheric structure to be interpolated to a 0.5-degree grid. The modeling results showed that the Yellowstone hotspot was responsible for regional tension and extension in the western U.S. interior over a 600-km wide area, with a rotation in the direction of maximum horizontal tensional stress from approximately north-south to east-west centered on the Yellowstone Plateau. Hotspot-related volcanism locally reduced the gravitational potential energy and stress magnitudes along the YSRP by systematic subsidence of topography along the YSRP track and increasing crustal thickness. Other implications from the stress modeling are that much of the high topography in the western U.S. interior is supported by low-density upper mantle (a consequence of assumed Pratt isostasy), and that plate boundary interactions between the North America and Pacific plates contribute to a change in stress tensor orientations from northeast-southwest to east-west in the Basin and Range of Nevada and Utah, and to a change from tension to compression in the northern Rocky Mountains of the Pacific Northwest. Together, the dynamic topography of the Yellowstone hotspot and Basin-Range, along with North

  18. How Many Hotspots are on Present-day Earth, and are all Plumes hot?

    NASA Astrophysics Data System (ADS)

    Herzberg, C.

    2004-12-01

    The petrological characteristics of primary magmas that exit the melting regime are sensitive indicators of mantle potential temperature. However, most primary magmas partially crystallize some olivine during transit to the surface, and erupted lavas are typically hybrid mixtures of olivine and solidified liquid. Primitive glass on the surface can have an MgO content that is lower than a parental magma from which it was derived, and a parental magma can differ from its primary magma by partial crystallization of olivine in a crustal magma chamber. However, the parental magma composition can be restored using a simple petrological procedure when olivine is the sole phenocryst phase. On Kilauea the most primitive magnesian glass has been reported to contain 15% MgO, and the most magnesian olivines contain Fo 90-91. The exchange coefficients (Kd) for FeO and MgO between these olivine and glass compositions are 0.25-0.28, much lower than 0.33-0.34 for olivine equilibrated with liquid in melting experiments. The only way to obtain the correct Kd is by computing the effects of dissolving olivine into a 15% MgO liquid composition. This procedure results in a crustal parental magma with 17-19% MgO and a mantle primary magma with 18-20% MgO. The potential crystallization temperature for Kilauea is 1400C, an estimate that includes the effects of 0.34% H2O. Hawaii is therefore a hotspot. This is the most fundamental geological constraint that all models are required to satisfy. It is independent of ongoing questions concerning the role of subducted crust and pyroxenite in the melting regime. A primary magma with 18-20% MgO is successfully reproduced by decompression melting in a hot plume with potential temperatures in excess of 1550C. Hawaii is the only hotspot Earth at the present time. The mantle below Iceland is comparatively cooler, warmer than oceanic ridges, but it was hotter during the early Tertiary. A preliminary analysis of volcanics in and around the African and

  19. Offsite radiation doses from Hanford Operations for the years 1983 through 1987: A comparison of results calculated by two methods

    SciTech Connect

    Soldat, J.K.

    1989-10-01

    This report compares the results of the calculation of potential radiation doses to the public by two different environmental dosimetric systems for the years 1983 through 1987. Both systems project the environmental movement of radionuclides released with effluents from Hanford operations; their concentrations in air, water, and foods; the intake of radionuclides by ingestion and inhalation; and, finally, the potential radiation doses from radionuclides deposited in the body and from external sources. The first system, in use for the past decade at Hanford, calculates radiation doses in terms of 50-year cumulative dose equivalents to body organs and to the whole body, based on the methodology defined in ICRP Publication 2. This system uses a suite of three computer codes: PABLM, DACRIN, and KRONIC. In the new system, 50-year committed doses are calculated in accordance with the recommendations of the ICRP Publications 26 and 30, which were adopted by the US Department of Energy (DOE) in 1985. This new system calculates dose equivalent (DE) to individual organs and effective dose equivalent (EDE). The EDE is a risk-weighted DE that is designed to be an indicator of the potential health effects arising from the radiation dose. 16 refs., 1 fig., 38 tabs.

  20. Identification of evolutionary hotspots based on genetic data from multiple terrestrial and aquatic taxa and gap analysis of hotspots in protected lands encompassed by the South Atlantic Landscape Conservation Cooperative.

    USGS Publications Warehouse

    Robinson, J.; Snider, M.; Duke, J.; Moyer, G.R.

    2014-01-01

    (displaying low genetic divergence and greater than average levels of genetic diversity) . Our results show the utility o f genetic data sets for identifying cross - species patterns of genetic  diversity and divergence (i.e., evolutionary hotspots) in aquatic and terrestrial environments for use in conservation design and delivery across the southeastern United States. 

  1. Sensitivity of clear-sky direct radiative effect of the aerosol to micro-physical properties by using 6SV radiative transfer model: preliminary results

    NASA Astrophysics Data System (ADS)

    Bassani, Cristiana; Tirelli, Cecilia; Manzo, Ciro; Pietrodangelo, Adriana; Curci, Gabriele

    2015-04-01

    The aerosol micro-physical properties are crucial to analyze their radiative impact on the Earth's radiation budget [IPCC, 2007]. The 6SV model, last generation of the Second Simulation of a Satellite Signal in the Solar Spectrum (6S) radiative transfer code [Kotchenova et al., 2007; Vermote et al., 1997] has been used to perform physically-based atmospheric correction of hyperspectral airborne and aircraft remote sensing data [Vermote et al., 2009; Bassani et al. 2010; Tirelli et al., 2014]. The atmospheric correction of hyperspectral data has been shown to be sensitive to the aerosol micro-physical properties, as reported in Bassani et al., 2012. The role of the aerosol micro-physical properties on the accuracy of the atmospheric correction of hyperspectral data acquired over water and land targets is investigated within the framework of CLAM-PHYM (Coasts and Lake Assessment and Monitoring by PRISMA HYperspectral Mission) and PRIMES (Synergistic use of PRISMA products with high resolution meteo-chemical simulations and their validation on ground and from satellite) projects, both funded by Italian Space Agency (ASI). In this work, the results of the radiative field of the Earth/Atmosphere coupled system simulated by using 6SV during the atmospheric correction of hyperspectral data are presented. The analysis of the clear-sky direct radiative effect is performed considering the aerosol micro-physical properties used to define the aerosol model during the atmospheric correction process. In particular, the AERONET [Holben et al., 1998] and FLEXAOD [Curci et al., 2014] micro-physical properties are used for each image to evaluate the contribution of the size distribution and refractive index of the aerosol type on the surface reflectance and on the direct radiative forcing. The results highlight the potential of the hyperspectral remote sensing data for atmospheric studies as well as for environmental studies. Currently, the future hyperspectral missions, such as the

  2. New Results About the Earth’s Van Allen Radiation Belts

    NASA Astrophysics Data System (ADS)

    Baker, Daniel

    2015-01-01

    The first great scientific discovery of the Space Age was that the Earth is enshrouded in toroids, or 'belts', of very high-energy magnetically trapped charged particles. Early observations of the radiation environment clearly indicated that the Van Allen belts could be delineated into an inner zone dominated by high-energy protons and an outer zone dominated by high-energy electrons. Subsequent studies showed that electrons in the energy range 100 keV < E< 1 MeV often populated both the inner and outer zones with a pronounced 'slot' region relatively devoid of energetic electrons existing between them. This two-belt structure for the Van Allen moderate-energy electron component was explained as being due to strong interactions of electrons with electromagnetic waves just inside the cold plasma (plasmapause) boundary. The energy distribution, spatial extent and particle species makeup of the Van Allen belts has been subsequently explored by several space missions. However, recent observations by the NASA dual-spacecraft Van Allen Probes mission have revealed wholly unexpected properties of the radiation belts, especially at highly relativistic (E > 2 MeV) and ultra-relativistic (E > 5 MeV) kinetic energies. In this presentation we show using high spatial and temporal resolution data from the Relativistic Electron-Proton Telescope (REPT) experiment on board the Van Allen Probes that multiple belts can exist concurrently and that an exceedingly sharp inner boundary exists for ultra-relativistic electrons. Using additionally available Van Allen Probes data, we demonstrate that these remarkable features of energetic electrons are not due to a physical boundary within Earth's intrinsic magnetic field. Neither is it likely that human-generated electromagnetic transmitter wave fields might produce such effects. Rather, we conclude from these unique measurements that slow natural inward radial diffusion combined with weak, but persistent, wave-particle pitch angle

  3. Hotspots and the evolution of the mantle

    NASA Technical Reports Server (NTRS)

    Anderson, D. L.

    1979-01-01

    Trace element patterns show that continental and ocean island basalts are complementary to mid-ocean ridge basalts (MORB). The relative sizes of the two source regions can be estimated from enrichment/depletion patterns. Their combined volume, computed from estimates of whole mantle abundances, occupies the entire upper mantle. The source regions appear to be the result of an early differentiation of the mantle. The MORB source evolved from the melt fraction which lost its late stage enriched fluids to the overlying plume source. The MORB source is primarily garnet and clinopyroxene, consistent with it being an eclogite cumulate.

  4. State background-radiation levels: results of measurements taken during 1975-1979

    SciTech Connect

    Myrick, T.E.; Berven, B.A.; Haywood, F.F.

    1981-11-01

    Background radiation levels across the United States have been measured by the Off-Site Pollutant Measurements Group of the Health and Safety Research Division at Oak Ridge National Laboratory (ORNL). These measurements have been conducted as part of the ORNL program of radiological surveillance at inactive uranium mills and sites formerly utilized during Manhattan Engineer District and early Atomic Energy Commission projects. The measurements included determination of /sup 226/Ra, /sup 232/Th, and /sup 238/U concentrations in surface soil samples and measurement of external gamma-ray exposure rates at 1 m above the ground surface at the location of soil sampling. This information is being utilized for comparative purposes to determine the extent of contamination present at the survey sites and surrounding off-site areas. The sampling program to date has provided background information at 356 locations in 33 states. External gamma-ray exposure rates were found to range from less than 1 to 34 ..mu..R/h, with an US average of 8.5 ..mu..R/h. The nationwide average concentrations of /sup 226/Ra, /sup 232/Th, and /sup 238/U in surface soil were determined to be 1.1, 0.98, and 1.0 pCi/g, respectively.

  5. Exploring spatiotemporal changes in ecosystem-service values and hotspots in China.

    PubMed

    Li, Guangdong; Fang, Chuanglin; Wang, Shaojian

    2016-03-01

    Although ecosystems are valuable, they have been allowed to deteriorate globally in recent decades. However, the spatiotemporal changes in ecosystem-service values (ESVs) and their hotspots in China are not well understood. Here, long-term land-cover data, the spatial analysis method and an econometric analysis model were used to examine these changes. The results indicate that the total terrestrial ESV decreased from US$2398.31 billion in 1990 to US$2347.56 billion in 2010 (converted to 2009 dollar values), which provides strong evidence for the tendency of ecosystems in China to deteriorate over time, albeit slightly. We also found that the changes in ESVs had significant spatial heterogeneity. Our analysis showed that the relationship between ESV and gross domestic product (GDP) is generally negative, but this relationship is not always fixed. The Loess Plateau, Guizhou, Hubei, Henan and Xinjiang continually presented concentrated hotspot areas of ESV changes, whereas coastal regions continually presented concentrated cold-spot areas. Overlap analyses and logistic regressions demonstrate that national ecological programs have clear effects on the improvement of ecosystems but that the effectiveness of different policies varies on spatial and temporal scales. The results of this study will support more effective decision-making around the implementation of ecological conservation policies. PMID:26760280

  6. Hotspots of damage by antagonists shape the spatial structure of plant-pollinator interactions.

    PubMed

    Rodríguez-Rodríguez, María C; Jordano, Pedro; Valido, Alfredo

    2015-08-01

    The balance between mutualistic and antagonistic plant-animal interactions and their spatial variation results in a highly dynamic mosaic of reproductive success within plant populations. Yet, the ecological drivers of this small-scale heterogeneity of interaction patterns and their outcomes remain virtually unexplored. We analyzed spatial structure in the frequency and intensity of interactions that vertebrate pollinators (birds and lizards) and invertebrate antagonists (florivores, nectar larcenists, and seed predators) had when interacting with the insular plant Isoplexis canariensis, and their effect on plant fitness. Spatially autocorrelated variation in plant reproductive success (fruit and viable seed set) emerged from the combined action of mutualists and antagonists, rather than reflecting the spatial pattern of any specific animal group. However, the influence of antagonists on plant fitness was stronger primarily due to the florivores' action on earlier reproductive stages, consuming and damaging floral structures before the arrival of pollinators. Our results indicate that the early action of antagonists creates hotspots of increased plant damage, where the effects of later acting mutualists are not translated into increased reproductive benefits. We foresee the potential for antagonists to shape the intra-population mosaics of plant fitness in situations where antagonists outnumber mutualists, when their interactions occur before those of mutualists, and when mutualists can detect and avoid damaged plants while foraging. Severely damaged plants in antagonistic hotspots might be excluded from the mating network and render a limited production of viable seeds, reducing both the growth rate of the plant population and the effective population size. PMID:26405743

  7. Structural and energetic hot-spots for the interaction between a ladder-like polycyclic ether and the anti-ciguatoxin antibody 10C9Fab.

    PubMed

    Ui, Mihoko; Tanaka, Yoshikazu; Tsumuraya, Takeshi; Fujii, Ikuo; Inoue, Masayuki; Hirama, Masahiro; Tsumoto, Kouhei

    2011-03-01

    The mechanism by which anti-ciguatoxin antibody 10C9Fab recognizes a fragment of ciguatoxin CTX3C (CTX3C-ABCDE) was investigated by mutational analysis based on structural data. 10C9Fab has an extraordinarily large and deep antigen-binding pocket at the center of its variable region. We mutated several residues located at the antigen-binding pocket to Ala, and kinetic analysis of the interactions between the mutant proteins and the antigen fragment was performed. The results indicate that some residues associated with the rigid antigen-binding pocket are structural hot-spots and that L-N94 is an energetic hot-spot for association of the antibody with the antigen fragment CTX3C-ABCDE, suggesting the importance of structural complementarity and energetic hot-spot interactions for specific recognition of polycyclic ethers. PMID:21161086

  8. Spherical disharmonics in the Earth sciences and the spatial solution: Ridges, hotspots, slabs, geochemistry and tomography correlations

    NASA Technical Reports Server (NTRS)

    Ray, Terrill W.; Anderson, Don L.

    1994-01-01

    strongest correlation is with lowermost mantle tomography, which is probably spurious. The most striking correlations are between mantle tomography and post-Pangean subducted slabs. The integrated locations of slabs correlate strongly with fast areas near the transition zone and the core-mantle boundary and with slow regions from 1022-1248 km depth. This seems to be consistent with the 'avalanching' downwellings which have been indicated by models of the mantle which include an endothermic phase transition at the 670-km discontinuity, although this is not a unique interpretation. Taken as a whole, these results suggest that slabs and associated cold downwellings are the dominant feature of mantle convection. Hotspot locations are no better correlated with lower mantle tomography than are ridge locations.

  9. Standing on the Shoulders of Giants: Results From the Radiation Oncology Academic Development and Mentorship Assessment Project (ROADMAP)

    SciTech Connect

    Holliday, Emma B.; Jagsi, Reshma; Thomas, Charles R.; Wilson, Lynn D.; Fuller, Clifton D.

    2014-01-01

    Purpose: To analyze survey information regarding mentorship practices and cross-correlate the results with objective metrics of academic productivity among academic radiation oncologists at US Accreditation Council for Graduate Medical Education (ACGME)-accredited residency training programs. Methods and Materials: An institutional review board-approved survey for the Radiation Oncology Academic Development and Mentorship Assessment Project (ROADMAP) was sent to 1031 radiation oncologists employed at an ACGME-accredited residency training program and administered using an international secure web application designed exclusively to support data capture for research studies. Data collected included demographics, presence of mentorship, and the nature of specific mentoring activities. Productivity metrics, including number of publications, number of citations, h-index, and date of first publication, were collected for each survey respondent from a commercially available online database, and m-index was calculated. Results: A total of 158 academic radiation oncologists completed the survey, 96 of whom reported having an academic/scientific mentor. Faculty with a mentor had higher numbers of publications, citations, and h- and m-indices. Differences in gender and race/ethnicity were not associated with significant differences in mentorship rates, but those with a mentor were more likely to have a PhD degree and were more likely to have more time protected for research. Bivariate fit regression modeling showed a positive correlation between a mentor's h-index and their mentee's h-index (R{sup 2} = 0.16; P<.001). Linear regression also showed significant correlates of higher h-index, in addition to having a mentor (P=.001), included a longer career duration (P<.001) and fewer patients in treatment (P=.02). Conclusions: Mentorship is widely believed to be important to career development and academic productivity. These results emphasize the importance of identifying and

  10. Compositional variations of the lunar crust: Results from radiative transfer modeling of central peak spectra

    NASA Astrophysics Data System (ADS)

    Cahill, J. T. S.; Lucey, P. G.; Wieczorek, M. A.

    2009-09-01

    We present model mineralogy of impact crater central peaks combined with crustal thickness and crater central peak depth of origin models to report multiple perspectives of lunar crustal composition with depth. Here we report the analyses of 55 impact crater central peaks and how their compositions directly relate to the lunar highlands sample suite. A radiative transfer model is used to analyze Clementine visible plus near-infrared spectra to place compositional constraints on these central peak materials. Central peaks analyzed are dominantly magnesian- and plagioclase-poor; strong compositional similarities to lunar Mg-suite materials are evident. Relative to crustal thickness estimates, central peak mineralogy becomes more plagioclase-rich as the crust thickens. Relative to the crust-mantle boundary, the origin of peaks with dominantly mafic mineralogy are confined to the lower crust and primarily within the South-Pole Aitken and Procellarum KREEP Terranes (PKT); additionally, central peaks with anorthositic mineralogy (>60 vol % plagioclase) are transported to the surface from all depths in the crustal column and confined to the Feldspathic Highlands Terrane (FHT). The discovery of mafic and magnesian materials, consistent with Mg-suite rocks of the sample collection, in all lunar terranes suggests that the process and sources that give rise to these types of rocks is not unique to the PKT and not necessarily dependent on incompatible elements for formation. The identification of ferroan and magnesian anorthositic material near the crust-mantle boundary of the FHT is also inconsistent with an increasing mafic/feldspar ratio and Mg' with depth in the crust.

  11. Magnetospheric Line Radiation: Survey results using 6.5 years of DEMETER spacecraft data

    NASA Astrophysics Data System (ADS)

    Bezdekova, Barbora; Nemec, Frantisek; Parrot, Michel; Santolik, Ondrej; Kruparova, Oksana

    2015-04-01

    Frequency-time spectrograms of electromagnetic emissions observed in the Earth's inner magnetosphere at frequencies between about 1 and 8 kHz sometimes consist of several nearly horizontal and almost equidistant intense lines. The emissions of this type were observed both by ground-based instruments and by satellites, and they are usually called Magnetospheric Line Radiation (MLR). We compiled a list of all MLR events observed by the low-altitude DEMETER spacecraft during the duration of the mission (2004-2010). Altogether, 1230 MLR events were identified, which likely represents the largest database available to date. We analyze a possible connection between the MLR occurrence and solar wind parameters using the superposed epoch analysis. We show that the MLR occurrence is enhanced during specific solar wind parameters, being larger in relation to the interplanetary shocks. We further show that there is a connection between the MLR occurrence and the season of the year, with the events being more frequent during the northern winter than during the northern summer. As for the spatial distribution of the event occurrence, the events are less frequent at geomagnetic longitudes of the South Atlantic Anomaly. We also analyze the energy spectra of electrons precipitating at the times of MLR events, and we derive energy-latitude plot of electron flux enhancements related to the MLR occurrence. Finally, we perform a detailed wave analysis of two MLR events for which high resolution multicomponent data are available. It is found that the events are right-handed nearly circularly polarized, propagating at oblique wave normal angles from larger radial distances and lower geomagnetic latitudes.

  12. Patient Radiation Exposure Tracking: Worldwide Programs and Needs—Results from the First IAEA Survey

    PubMed Central

    Rehani, Madan M.; Frush, Donald P.; Berris, Theocharis; Einstein, Andrew J.

    2012-01-01

    The purpose of this study was to assess the current status of patient radiation exposure tracking internationally, gauge interest and develop recommendations for implementation. A survey questionnaire was distributed to representatives of countries to obtain information, including the existence of a patient exposure tracking program currently available in the country, plans for future programs, perceived needs and goals of future programs, which examinations will be tracked, whether procedure tracking alone or dose tracking is planned, and which dose quantities will be tracked. Responses from 76 countries, including all of the six most populous countries and 16 of the 20 most populous, showed that although no country has yet implemented a patient exposure tracking program at a national level, there is increased interest in this issue. Eight countries (11%) indicated that such a program is actively being planned and 3 (4%) stated that they have a program for tracking procedures only, but not for dose. Twenty-two (29%) feel that such a program will be “extremely useful”, 46 (60%) “very useful” and 8 (11%) “moderately useful”, with no respondents stating “Mildly useful” or “Not useful”. Ninety-nine percent of countries indicated an interest in developing and promoting such a program. In a first global survey covering 76 countries, it is clear that no country has yet achieved exposure tracking at a national level, although there are successful examples at sub-national level. Almost all have indicated interest and some have plans to achieve dose tracking in the near future. PMID:22840382

  13. Influential Factors and Synergies for Radiation-Gene Therapy on Cancer

    PubMed Central

    Lin, Mei; Huang, Junxing; Shi, Yujuan; Xiao, Yanhong; Guo, Ting

    2015-01-01

    Radiation-gene therapy, a dual anticancer strategy of radiation therapy and gene therapy through connecting radiation-inducible regulatory sequence to therapeutic gene, leading to the gene being induced to express by radiation while radiotherapy is performed and finally resulting in a double synergistic antitumor effect of radiation and gene, has become one of hotspots in the field of cancer treatment in recent years. But under routine dose of radiation, especially in the hypoxia environment of solid tumor, it is difficult for this therapy to achieve desired effect because of low activity of radiation-inducible regulatory elements, low level and transient expression of target gene induced by radiation, inferior target specificity and poor biosecurity, and so on. Based on the problems existing in radiation-gene therapy, many efforts have been devoted to the curative effect improvement of radiation-gene therapy by various means to increase radiation sensitivity or enhance target gene expression and the expression's controllability. Among these synergistic techniques, gene circuit, hypoxic sensitization, and optimization of radiation-induced sequence exhibit a good application potential. This review provides the main influential factors to radiation-gene therapy on cancer and the synergistic techniques to improve the anticancer effect of radiation-gene therapy. PMID:26783511

  14. Multiscale DSA simulations for efficient hotspot analysis

    NASA Astrophysics Data System (ADS)

    Hori, Yoshihiro; Yoshimoto, Kenji; Taniguchi, Takashi; Ohshima, Masahiro

    2014-03-01

    In this study, we have investigated how to link "large-scale simulations with the simplified models" to "mesoscale simulations with the detailed models." For the simplified model, we have applied so-called the generalized Ohta-Kawasaki (gOK) model. Our simulation flow was implemented by two steps: 1) parallel computations of block copolymer annealing with the simplified model, 2) detailed analysis of the defects with the SCFT. The local volumetric densities of block copolymers calculated by the simplified models were used as an input for the SCFT. Then the SCFT simulations were performed under the constraints in which the density field was driven to be the one obtained from the simplified model. Using the resultant partition functions, we were able to obtain spatial distributions of the free chain ends and the connection points of the blocks. Note that the chain conformation of block copolymer is an important, but missing component of the simplified models; this multi-scale approach is expected to be useful for further understanding the origin and stability of DSA defects.

  15. Identifying Riverine Erosional Hotspots Using Airborne Lidar

    NASA Astrophysics Data System (ADS)

    Wick, M. J.; Gran, K. B.

    2012-12-01

    New high-resolution airborne lidar data may make it possible to develop a predictive model for stream erosion using only remote data. These data could be invaluable to help identify sediment sources in turbidity-impaired streams, simplifying the development of management plans to reduce sediment loading. The recent release of lidar-derived 3m DEMs (digital elevation models) for Northeastern Minnesota, USA, offers a unique opportunity to test this possibility. Here, we develop a GIS-based predictive model for erosion potential along Amity Creek in Duluth, Minnesota, and compare the results to two field datasets: Bank Erosion Hazard Index (BEHI) assessments, and field data collected after a large flood in June 2012. Three major factors were used to predict erosion potential: a stream-power based erosion index, channel confinement, and soil erodibility. A stream-power based erosion index was calculated with slope and upstream area derived from Lidar data. Because erosion potential is elevated where the stream interacts with high valley walls cut into till, we also included a valley confinement factor that included proximity to high valley bluffs. Lastly, we use the Soil Survey Geographic (SSURGO) database to extract K values, the erodibility factor in the Revised Universal Soil Loss equation, along the channel corridor. Two separate field surveys were conducted for comparison to one another and to GIS-based predictions: BEHI assessments at 27 points along the river and river walk surveys to assess erosion that occurred during an estimated >100-year flood on June 19th - 20th, 2012. This historic flood event offered us the opportunity to collect post-storm data that can be used to assess the validity of our predictive model. We mapped all observable erosion features including undercutting, slumps, and scouring, as well as when the bank and bed geology changed from sediments to bedrock. Preliminary results show the GIS-based erosion predictions do have a positive

  16. Genome Hotspots for Nucleotide Substitutions and the Evolution of Influenza A (H1N1) Human Strains

    PubMed Central

    Civetta, Alberto; Ostapchuk, David Cecil Murphy; Nwali, Basil

    2016-01-01

    In recent years a number of studies have brought attention to the role of positive selection during the evolution of antigenic escape by influenza strains. Particularly, the identification of positively selected sites within antigenic domains of viral surface proteins has been used to suggest that the evolution of viral–host receptor binding specificity is driven by selection. Here we show that, following the 1918 outbreak, the antigenic sites of the hemagglutinin (HA) viral surface protein and the stalk region of neuraminidase became substitution hotspots. The hotspots show similar patterns of nucleotide substitution bias at synonymous and nonsynonymous sites. Such bias imposes directionality in amino acid replacements that can influence signals of selection at antigenic sites. Our results suggest that the high accumulation of substitutions within the antigenic sites of HA can explain not only cases of antigenic escape by antigenic drift but also lead to occasional episodes of viral extinction. PMID:26988249

  17. Environmental risk factors and hotspot analysis of dengue distribution in Pakistan.

    PubMed

    Khalid, Bushra; Ghaffar, Abdul

    2015-11-01

    This study is an attempt to find out the factors responsible for sudden dengue outbreak in different cities of Pakistan during 2011. For this purpose, spatio-temporal distribution of dengue in Islamabad, Rawalpindi, Lahore, and Karachi has been taken into account. According to the available data, the factors responsible for this spread includes climate covariates like rainfall, temperature, and wind speed; social covariates like population, and area of locality, and environmental risk factors like drainage pattern and geo-hydrological conditions. Reported dengue cases from localities and Shuttle Radar Topography Mission (SRTM) 90 m digital elevation model (DEM) of study areas have been processed for hotspots, regression model and stream density in the localities of high dengue incidence. The relationship of daily dengue incidence with climate covariates during the months of July-October of the study year is analyzed. Results show that each dry spell of 2-4 days provides suitable conditions for the development and survival of dengue vectors during the wet months of July and August in the areas of high stream density and population. Very few cases have been reported in July while higher number of cases reported in the months of August, September, until late October. Hotspot analysis highlights the areas of high dengue incidence while regression analysis shows the relationship between the population and the areas of localities with the dengue incidence. PMID:25869291

  18. Infant Mortality and Social Environment in Georgia: An application of hotspot detection and prioritization†

    PubMed Central

    Yang, Tse-Chuan; McManus, Brian

    2011-01-01

    Recent years have witnessed the growth of new information technologies and their applications to various disciplines. The goal of this paper is to demonstrate how the two innovative methods, upper level set scan (ULS) hotspot detection and the multicriterion prioritization scheme, facilitate population health and break new ground in public health surveillance. It is believed that the social environment (i.e. social conditions and social capital) is one of the determinants of human health. Using infant health data and 10 additional indicators of social environment in the 159 counties of Georgia, ULS identified 52 counties that are in double jeopardy (high infant mortality and a high rate of low infant birth weight). The multicriterion ranking scheme suggested that there was no conspicuous spatial cluster of ranking orders, which improved the traditional decision making by visual geographic cluster. Both hotspot detection and ranking methods provided an empirical basis for re-allocating limited resources and several policy implications could be drawn from these analytic results. PMID:22022207

  19. Environmental risk factors and hotspot analysis of dengue distribution in Pakistan

    NASA Astrophysics Data System (ADS)

    Khalid, Bushra; Ghaffar, Abdul

    2015-11-01

    This study is an attempt to find out the factors responsible for sudden dengue outbreak in different cities of Pakistan during 2011. For this purpose, spatio-temporal distribution of dengue in Islamabad, Rawalpindi, Lahore, and Karachi has been taken into account. According to the available data, the factors responsible for this spread includes climate covariates like rainfall, temperature, and wind speed; social covariates like population, and area of locality, and environmental risk factors like drainage pattern and geo-hydrological conditions. Reported dengue cases from localities and Shuttle Radar Topography Mission (SRTM) 90 m digital elevation model (DEM) of study areas have been processed for hotspots, regression model and stream density in the localities of high dengue incidence. The relationship of daily dengue incidence with climate covariates during the months of July-October of the study year is analyzed. Results show that each dry spell of 2-4 days provides suitable conditions for the development and survival of dengue vectors during the wet months of July and August in the areas of high stream density and population. Very few cases have been reported in July while higher number of cases reported in the months of August, September, until late October. Hotspot analysis highlights the areas of high dengue incidence while regression analysis shows the relationship between the population and the areas of localities with the dengue incidence.

  20. Borneo and Indochina are major evolutionary hotspots for Southeast Asian biodiversity.

    PubMed

    de Bruyn, Mark; Stelbrink, Björn; Morley, Robert J; Hall, Robert; Carvalho, Gary R; Cannon, Charles H; van den Bergh, Gerrit; Meijaard, Erik; Metcalfe, Ian; Boitani, Luigi; Maiorano, Luigi; Shoup, Robert; von Rintelen, Thomas

    2014-11-01

    Tropical Southeast (SE) Asia harbors extraordinary species richness and in its entirety comprises four of the Earth's 34 biodiversity hotspots. Here, we examine the assembly of the SE Asian biota through time and space. We conduct meta-analyses of geological, climatic, and biological (including 61 phylogenetic) data sets to test which areas have been the sources of long-term biological diversity in SE Asia, particularly in the pre-Miocene, Miocene, and Plio-Pleistocene, and whether the respective biota have been dominated by in situ diversification, immigration and/or emigration, or equilibrium dynamics. We identify Borneo and Indochina, in particular, as major "evolutionary hotspots" for a diverse range of fauna and flora. Although most of the region's biodiversity is a result of both the accumulation of immigrants and in situ diversification, within-area diversification and subsequent emigration have been the predominant signals characterizing Indochina and Borneo's biota since at least the early Miocene. In contrast, colonization events are comparatively rare from younger volcanically active emergent islands such as Java, which show increased levels of immigration events. Few dispersal events were observed across the major biogeographic barrier of Wallace's Line. Accelerated efforts to conserve Borneo's flora and fauna in particular, currently housing the highest levels of SE Asian plant and mammal species richness, are critically required. PMID:25070971

  1. The highly-cited Electrocardiogram-related articles in science citation index expanded: characteristics and hotspots.

    PubMed

    Yang, Xianglin; Gu, Jiaojiao; Yan, Hong; Xu, Zhi; Ren, Bing; Yang, Yaming; Yang, Xiaodong; Chen, Qi; Tan, Shaohua

    2014-01-01

    We used bibliometric analysis methodology in the expanded Science Citation Index to identify highly-cited electrocardiogram (ECG)-related articles with total citations (TC2012) exceeding 100 from the publication year to 2012. Web of Science search tools were used to identify the highly-cited articles. The aspects analyzed for highly cited publications included effect of time on citation analysis, journals and Web of Science categories, number of authors per publication, originating institutions and countries, total citation and total citation per year life cycles of articles (C2012) and research hotspots. Results showed that a total of 467 electrocardiogram-related publications were regarded as the highly-cited publications. TC2012 ranged from 101 to 2879, with 215 as the average number of citations. No highly-cited publications have emerged yet during the first two years of the present 2010 Decade. All 11 countries and institutions originating highly-cited ECG-related publications were developed countries, USA in 9 of them. Four subject categories were identified as hotspots by total citations TC2012 and C2012: atrial fibrillation, long QT syndrome, angina and myocardial infarction, and risk factor analysis and health evaluation. PMID:24742585

  2. A phylogenetically informed delineation of floristic regions within a biodiversity hotspot in Yunnan, China

    PubMed Central

    Li, Rong; Kraft, Nathan J. B.; Yang, Jie; Wang, Yuhua

    2015-01-01

    Traditional attempts to delineate floristic regions typically focus on species distributions, often ignoring the rich context that phylogenetic relationships can provide. In this study, we explore how phylogenetic relatedness, taxonomic composition, and regional phylogenetic structure change across a global biodiversity hotspot region, Yunnan, located in southwestern China. We propose a system of floristic regions within Yunnan by combining data on the distributions and phylogenetic relationships of 1,983 genera of native seed plants. We identified eight distinct floristic regions in Yunnan, which were grouped into two larger northern and southern geographical units. Phylogenetic relatedness was well correlated with taxonomic composition between floras in Yunnan. Across the Yunnan region we examined, the central Yunnan region shows the lowest level of spatial turnover in phylogenetic relationships and taxonomic composition of the floristic assemblages. Using null model analyses, we found evidence of nonrandom phylogenetic structure across the region, in which four areas show higher phylogenetic turnover than expected given the underlying taxonomic composition between sites. Our results show that the integration of phylogenetic information can provide valuable insight in floristic assessments, and help us to better understand the structure of a global biodiversity hotspot. PMID:25820037

  3. Using expert informed GIS to locate important marine social-ecological hotspots.

    PubMed

    Mahboubi, Pouyan; Parkes, Margot; Stephen, Craig; Chan, Hing Man

    2015-09-01

    The marine environment provides significant benefits to many local communities. Pressure to develop coastal waterways worldwide creates an urgent need for tools to locate marine spaces that have important social or ecological values, and to quantify their relative importance. The primary objective of this study was to develop, apply and critically assess a tool to identify important social-ecological hotspots in the marine environment. The study was conducted in a typical coastal community in northern British Columbia, Canada. This expert-informed GIS, or xGIS, tool used a survey instrument to draw on the knowledge of local experts from a range of backgrounds with respect to a series of 12 social-ecological value attributes, such as biodiversity, cultural and economic values. We identified approximately 1500 polygons on marine maps and assigned relative values to them using a token distribution exercise. A series of spatial statistical analyses were performed to locate and quantify the relative social-ecological importance of marine spaces and the results were ultimately summarized in a single hotspot map of the entire study area. This study demonstrates the utility of xGIS as a useful tool for stakeholders and environmental managers engaged in the planning and management of marine resources at the local and regional levels. PMID:25864941

  4. Broad plumes rooted at the base of the Earth's mantle beneath major hotspots.

    PubMed

    French, Scott W; Romanowicz, Barbara

    2015-09-01

    Plumes of hot upwelling rock rooted in the deep mantle have been proposed as a possible origin of hotspot volcanoes, but this idea is the subject of vigorous debate. On the basis of geodynamic computations, plumes of purely thermal origin should comprise thin tails, only several hundred kilometres wide, and be difficult to detect using standard seismic tomography techniques. Here we describe the use of a whole-mantle seismic imaging technique--combining accurate wavefield computations with information contained in whole seismic waveforms--that reveals the presence of broad (not thin), quasi-vertical conduits beneath many prominent hotspots. These conduits extend from the core-mantle boundary to about 1,000 kilometres below Earth's surface, where some are deflected horizontally, as though entrained into more vigorous upper-mantle circulation. At the base of the mantle, these conduits are rooted in patches of greatly reduced shear velocity that, in the case of Hawaii, Iceland and Samoa, correspond to the locations of known large ultralow-velocity zones. This correspondence clearly establishes a continuous connection between such zones and mantle plumes. We also show that the imaged conduits are robustly broader than classical thermal plume tails, suggesting that they are long-lived, and may have a thermochemical origin. Their vertical orientation suggests very sluggish background circulation below depths of 1,000 kilometres. Our results should provide constraints on studies of viscosity layering of Earth's mantle and guide further research into thermochemical convection. PMID:26333468

  5. Drastic underestimation of amphipod biodiversity in the endangered Irano-Anatolian and Caucasus biodiversity hotspots.

    PubMed

    Katouzian, Ahmad-Reza; Sari, Alireza; Macher, Jan N; Weiss, Martina; Saboori, Alireza; Leese, Florian; Weigand, Alexander M

    2016-01-01

    Biodiversity hotspots are centers of biological diversity and particularly threatened by anthropogenic activities. Their true magnitude of species diversity and endemism, however, is still largely unknown as species diversity is traditionally assessed using morphological descriptions only, thereby ignoring cryptic species. This directly limits evidence-based monitoring and management strategies. Here we used molecular species delimitation methods to quantify cryptic diversity of the montane amphipods in the Irano-Anatolian and Caucasus biodiversity hotspots. Amphipods are ecosystem engineers in rivers and lakes. Species diversity was assessed by analysing two genetic markers (mitochondrial COI and nuclear 28S rDNA), compared with morphological assignments. Our results unambiguously demonstrate that species diversity and endemism is dramatically underestimated, with 42 genetically identified freshwater species in only five reported morphospecies. Over 90% of the newly recovered species cluster inside Gammarus komareki and G. lacustris; 69% of the recovered species comprise narrow range endemics. Amphipod biodiversity is drastically underestimated for the studied regions. Thus, the risk of biodiversity loss is significantly greater than currently inferred as most endangered species remain unrecognized and/or are only found locally. Integrative application of genetic assessments in monitoring programs will help to understand the true magnitude of biodiversity and accurately evaluate its threat status. PMID:26928527

  6. Drastic underestimation of amphipod biodiversity in the endangered Irano-Anatolian and Caucasus biodiversity hotspots