92 research outputs found

    Grain Surface Models and Data for Astrochemistry

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    AbstractThe cross-disciplinary field of astrochemistry exists to understand the formation, destruction, and survival of molecules in astrophysical environments. Molecules in space are synthesized via a large variety of gas-phase reactions, and reactions on dust-grain surfaces, where the surface acts as a catalyst. A broad consensus has been reached in the astrochemistry community on how to suitably treat gas-phase processes in models, and also on how to present the necessary reaction data in databases; however, no such consensus has yet been reached for grain-surface processes. A team of ∼25 experts covering observational, laboratory and theoretical (astro)chemistry met in summer of 2014 at the Lorentz Center in Leiden with the aim to provide solutions for this problem and to review the current state-of-the-art of grain surface models, both in terms of technical implementation into models as well as the most up-to-date information available from experiments and chemical computations. This review builds on the results of this workshop and gives an outlook for future directions

    Primordial Black Hole Formation in a Double Inflation Model in Supergravity

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    It has been recently pointed out that the initial value problem in new inflation models is naturally solved by supergravity effects if there exists a pre-inflation before the new inflation. We study this double inflation model in details and find that density fluctuations on small cosmological scales are much larger than those on large scales due to peculiar property of the new inflation. We show that this results in production of primordial black holes which have 1M\sim 1 M_{\odot} masses in a certain parameter region of the double inflation model. We stress that these black holes may be identified with MACHOs observed in the halo of our galaxy.Comment: 19 pages (RevTeX file), KUNS-147

    Product-Group Unification in Type IIB String Thoery

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    The product-group unification is a model of unified theories, in which masslessness of the two Higgs doublets and absence of dimension-five proton decay are guaranteed by a symmetry. It is based on SU(5) x U(N) (N=2,3) gauge group. It is known that various features of the model are explained naturally, when it is embedded in a brane world. This article describes an idea of how to accommodate all the particles of the model in Type IIB brane world. The GUT-breaking sector is realized by a D3--D7 system, and chiral quarks and leptons arise from intersection of D7-branes. The D-brane configuration can be a geometric realization of the non-parallel family structure of quarks and leptons, an idea proposed to explain the large mixing angles observed in the neutrino oscillation. The tri-linear interaction of the next-to-minimal supersymmetric standard model is obtained naturally in some cases.Comment: 33 pages, 5 figure

    Probing the DeltaNN component of 3He

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    The 3He(gamma,pi^+/- p) reactions were measured simultaneously over a tagged photon energy range of 800<E_gamma<1120 MeV, well above the Delta resonance region. An analysis was performed to kinematically isolate Delta knockout events from conventional Delta photoproduction events, and a statistically significant excess of pi+p events was identified, consistent with Delta++ knockout. Two methods were used to estimate the DeltaNN probability in the 3He ground state, corresponding to the observed knockout cross section. The first gave a lower probability limit of 1.5+/-0.6+/-0.5%; the second yielded an upper limit of about 2.6%.Comment: 14 page

    Altered Cognitive Function in Men Treated for Prostate Cancer with LHRH Analogues and Cyproterone Acetate: A Randomised Controlled Trial

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    Objective. Luteinising hormone releasing hormone (LHRH) analogues have been associated with memory impairments in women using these drugs for gynaecological conditions. This is the first systematic investigation of the cognitive effects of LHRH analogues in male patients. Methods. 82 men with non-localised prostate cancer were randomly assigned to receive continuous leuprorelin (LHRH analogue), goserelin (LHRH analogue), cyproterone acetate (steroidal antiandrogen) or close clinical monitoring. These patients underwent cognitive assessments at baseline and before commencement of treatment (77) then 6 months later (65). Results. Compared with baseline assessments, men administered androgen suppression monotherapy performed worse in 2/12 tests of attention and memory. 24/50 men randomised to active treatment and assessed 6 months later demonstrated clinically significant decline in one or more cognitive tests but not one patient randomised to close monitoring showed a decline in any test performance. Conclusion. Pharmacological androgen suppression monotherapy for prostate cancer may be associated with impaired memory, attention and executive functions

    Central sites. Atlantis Massif: Serpentinisation and life

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    International Ocean Discovery Program (IODP) Expedition 357 successfully cored an east–west transect across the southern wall of Atlantis Massif on the western flank of the Mid-Atlantic Ridge (MAR) to study the links between serpentinization processes and microbial activity in the shallow subsurface of highly altered ultramafic and mafic sequences that have been uplifted to the seafloor along a major detachment fault zone. The primary goals of this expedition were to (1) examine the role of serpentinization in driving hydrothermal systems, sustaining microbial communities, and sequestering carbon; (2) characterize the tectonomagmatic processes that lead to lithospheric heterogeneities and detachment faulting; and (3) assess how abiotic and biotic processes change with variations in rock type and progressive exposure on the seafloor. To accomplish these objectives, we developed a coring and sampling strategy centered on the use of seabed drills—the first time that such systems have been used in the scientific ocean drilling programs. This technology was chosen in the hope of achieving high recovery of the carbonate cap sequences and intact contact and deformation relationships. The expedition plans also included several engineering developments to assess geochemical parameters during drilling; sample bottom water before, during, and after drilling; supply synthetic tracers during drilling for contamination assessment; acquire in situ electrical resistivity and magnetic susceptibility measurements for assessing fractures, fluid flow, and extent of serpentinization; and seal boreholes to provide opportunities for future experiments. Seventeen holes were drilled at nine sites across Atlantis Massif, with two sites on the eastern end of the southern wall (Sites M0068 and M0075), three sites in the central section of the southern wall north of the Lost City hydrothermal field (Sites M0069, M0072, and M0076), two sites on the western end (Sites M0071 and M0073), and two sites north of the southern wall in the direction of the central dome of the massif and Integrated Ocean Drilling Program Site U1309 (Sites M0070 and M0074). Use of seabed drills enabled collection of more than 57 m of core, with borehole penetration ranging from 1.30 to 16.44 meters below seafloor and core recoveries as high as 74.76% of total penetration. This high level of recovery of shallow mantle sequences is unprecedented in the history of ocean drilling. The cores recovered along the southern wall of Atlantis Massif have highly heterogeneous lithologies, types of alteration, and degrees of deformation. The ultramafic rocks are dominated by harzburgites with intervals of dunite and minor pyroxenite veins, as well as gabbroic rocks occurring as melt impregnations and veins, all of which provide information about early magmatic processes and the magmatic evolution in the southernmost portion of Atlantis Massif. Dolerite dikes and basaltic rocks represent the latest stage of magmatic activity. Overall, the ultramafic rocks recovered during Expedition 357 reveal a high degree of serpentinization, as well as metasomatic talc-amphibole-chlorite overprinting and local rodingitization. Metasomatism postdates an early phase of serpentinization but predates late-stage intrusion and alteration of dolerite dikes and the extrusion of basalt. The intensity of alteration is generally lower in the gabbroic and doleritic rocks. Chilled margins in dolerite intruded into talc-amphibole-chlorite schists are observed at the most eastern Site M0075. Deformation in Expedition 357 cores is variable and dominated by brecciation and formation of localized shear zones; the degree of carbonate veining was lower than anticipated. All types of variably altered and deformed ultramafic and mafic rocks occur as components in sedimentary breccias and as fault scarp rubble. The sedimentary cap rocks include basaltic breccias with a carbonate sand matrix and/or fossiliferous carbonate. Fresh glass on basaltic components was observed in some of the breccias. The expedition also successfully applied new technologies, namely (1) extensively using an in situ sensor package and water sampling system on the seabed drills for evaluating real-time dissolved oxygen and methane, pH, oxidation-reduction potential (ORP), temperature, and conductivity during drilling; (2) deploying a borehole plug system for sealing seabed drill boreholes at four sites to allow access for future sampling; and (3) proving that tracers can be delivered into drilling fluids when using seabed drills. The rock drill sensor packages and water sampling enabled detection of elevated dissolved methane and hydrogen concentrations during and/or after drilling, with “hot spots” of hydrogen observed over Sites M0068–M0072 and methane over Sites M0070–M0072. Shipboard determination of contamination tracer delivery confirmed appropriate sample handling procedures for microbiological and geochemical analyses, which will aid all subsequent microbiological investigations that are part of the science party sampling plans and will verify this new tracer delivery technology for seabed drill rigs. Shipboard investigation of biomass density in select samples revealed relatively low and variable cell densities, and enrichment experiments set up shipboard reveal growth. Thus, we anticipate achieving many of the deep biosphere–related objectives of the expedition through continued scientific investigation in the coming years. Finally, although not an objective of the expedition, we were serendipitously able to generate a high-resolution (20 m per pixel) multibeam bathymetry map across the entire Atlantis Massif and the nearby fracture zone, MAR, and eastern conjugate, taking advantage of weather and operational downtime. This will assist science party members in evaluating and interpreting tectonic and mass-wasting processes at Atlantis Massif

    Expedition 357 methods

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    This chapter documents the primary procedures and methods employed by the operational and scientific groups during the offshore and onshore phases of International Ocean Discovery Program (IODP) Expedition 357. This information concerns only shipboard and Onshore Science Party (OSP) methods described in the site chapters. Methods for postexpedition research conducted on Expedition 357 samples and data will be described in individual scientific contributions. Detailed drilling and engineering operations are described in the Operations section of each site chapter

    Expedition 357 summary. Atlantis Massif: Serpentinisation and life

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    International Ocean Discovery Program (IODP) Expedition 357 successfully cored an east–west transect across the southern wall of Atlantis Massif on the western flank of the Mid-Atlantic Ridge (MAR) to study the links between serpentinization processes and microbial activity in the shallow subsurface of highly altered ultramafic and mafic sequences that have been uplifted to the seafloor along a major detachment fault zone. The primary goals of this expedition were to (1) examine the role of serpentinization in driving hydrothermal systems, sustaining microbial communities, and sequestering carbon; (2) characterize the tectonomagmatic processes that lead to lithospheric heterogeneities and detachment faulting; and (3) assess how abiotic and biotic processes change with variations in rock type and progressive exposure on the seafloor. To accomplish these objectives, we developed a coring and sampling strategy centered on the use of seabed drills—the first time that such systems have been used in the scientific ocean drilling programs. This technology was chosen in the hope of achieving high recovery of the carbonate cap sequences and intact contact and deformation relationships. The expedition plans also included several engineering developments to assess geochemical parameters during drilling; sample bottom water before, during, and after drilling; supply synthetic tracers during drilling for contamination assessment; acquire in situ electrical resistivity and magnetic susceptibility measurements for assessing fractures, fluid flow, and extent of serpentinization; and seal boreholes to provide opportunities for future experiments. Seventeen holes were drilled at nine sites across Atlantis Massif, with two sites on the eastern end of the southern wall (Sites M0068 and M0075), three sites in the central section of the southern wall north of the Lost City hydrothermal field (Sites M0069, M0072, and M0076), two sites on the western end (Sites M0071 and M0073), and two sites north of the southern wall in the direction of the central dome of the massif and Integrated Ocean Drilling Program Site U1309 (Sites M0070 and M0074). Use of seabed drills enabled collection of more than 57 m of core, with borehole penetration ranging from 1.30 to 16.44 meters below seafloor and core recoveries as high as 74.76% of total penetration. This high level of recovery of shallow mantle sequences is unprecedented in the history of ocean drilling. The cores recovered along the southern wall of Atlantis Massif have highly heterogeneous lithologies, types of alteration, and degrees of deformation. The ultramafic rocks are dominated by harzburgites with intervals of dunite and minor pyroxenite veins, as well as gabbroic rocks occurring as melt impregnations and veins, all of which provide information about early magmatic processes and the magmatic evolution in the southernmost portion of Atlantis Massif. Dolerite dikes and basaltic rocks represent the latest stage of magmatic activity. Overall, the ultramafic rocks recovered during Expedition 357 reveal a high degree of serpentinization, as well as metasomatic talc-amphibole-chlorite overprinting and local rodingitization. Metasomatism postdates an early phase of serpentinization but predates late-stage intrusion and alteration of dolerite dikes and the extrusion of basalt. The intensity of alteration is generally lower in the gabbroic and doleritic rocks. Chilled margins in dolerite intruded into talc-amphibole-chlorite schists are observed at the most eastern Site M0075. Deformation in Expedition 357 cores is variable and dominated by brecciation and formation of localized shear zones; the degree of carbonate veining was lower than anticipated. All types of variably altered and deformed ultramafic and mafic rocks occur as components in sedimentary breccias and as fault scarp rubble. The sedimentary cap rocks include basaltic breccias with a carbonate sand matrix and/or fossiliferous carbonate. Fresh glass on basaltic components was observed in some of the breccias. The expedition also successfully applied new technologies, namely (1) extensively using an in situ sensor package and water sampling system on the seabed drills for evaluating real-time dissolved oxygen and methane, pH, oxidation-reduction potential (ORP), temperature, and conductivity during drilling; (2) deploying a borehole plug system for sealing seabed drill boreholes at four sites to allow access for future sampling; and (3) proving that tracers can be delivered into drilling fluids when using seabed drills. The rock drill sensor packages and water sampling enabled detection of elevated dissolved methane and hydrogen concentrations during and/or after drilling, with “hot spots” of hydrogen observed over Sites M0068–M0072 and methane over Sites M0070–M0072. Shipboard determination of contamination tracer delivery confirmed appropriate sample handling procedures for microbiological and geochemical analyses, which will aid all subsequent microbiological investigations that are part of the science party sampling plans and will verify this new tracer delivery technology for seabed drill rigs. Shipboard investigation of biomass density in select samples revealed relatively low and variable cell densities, and enrichment experiments set up shipboard reveal growth. Thus, we anticipate achieving many of the deep biosphere–related objectives of the expedition through continued scientific investigation in the coming years. Finally, although not an objective of the expedition, we were serendipitously able to generate a high-resolution (20 m per pixel) multibeam bathymetry map across the entire Atlantis Massif and the nearby fracture zone, MAR, and eastern conjugate, taking advantage of weather and operational downtime. This will assist science party members in evaluating and interpreting tectonic and mass-wasting processes at Atlantis Massif

    Western sites. Atlantis Massif: Serpentinisation and life

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    International Ocean Discovery Program (IODP) Expedition 357 successfully cored an east–west transect across the southern wall of Atlantis Massif on the western flank of the Mid-Atlantic Ridge (MAR) to study the links between serpentinization processes and microbial activity in the shallow subsurface of highly altered ultramafic and mafic sequences that have been uplifted to the seafloor along a major detachment fault zone. The primary goals of this expedition were to (1) examine the role of serpentinization in driving hydrothermal systems, sustaining microbial communities, and sequestering carbon; (2) characterize the tectonomagmatic processes that lead to lithospheric heterogeneities and detachment faulting; and (3) assess how abiotic and biotic processes change with variations in rock type and progressive exposure on the seafloor. To accomplish these objectives, we developed a coring and sampling strategy centered on the use of seabed drills—the first time that such systems have been used in the scientific ocean drilling programs. This technology was chosen in the hope of achieving high recovery of the carbonate cap sequences and intact contact and deformation relationships. The expedition plans also included several engineering developments to assess geochemical parameters during drilling; sample bottom water before, during, and after drilling; supply synthetic tracers during drilling for contamination assessment; acquire in situ electrical resistivity and magnetic susceptibility measurements for assessing fractures, fluid flow, and extent of serpentinization; and seal boreholes to provide opportunities for future experiments. Seventeen holes were drilled at nine sites across Atlantis Massif, with two sites on the eastern end of the southern wall (Sites M0068 and M0075), three sites in the central section of the southern wall north of the Lost City hydrothermal field (Sites M0069, M0072, and M0076), two sites on the western end (Sites M0071 and M0073), and two sites north of the southern wall in the direction of the central dome of the massif and Integrated Ocean Drilling Program Site U1309 (Sites M0070 and M0074). Use of seabed drills enabled collection of more than 57 m of core, with borehole penetration ranging from 1.30 to 16.44 meters below seafloor and core recoveries as high as 74.76% of total penetration. This high level of recovery of shallow mantle sequences is unprecedented in the history of ocean drilling. The cores recovered along the southern wall of Atlantis Massif have highly heterogeneous lithologies, types of alteration, and degrees of deformation. The ultramafic rocks are dominated by harzburgites with intervals of dunite and minor pyroxenite veins, as well as gabbroic rocks occurring as melt impregnations and veins, all of which provide information about early magmatic processes and the magmatic evolution in the southernmost portion of Atlantis Massif. Dolerite dikes and basaltic rocks represent the latest stage of magmatic activity. Overall, the ultramafic rocks recovered during Expedition 357 reveal a high degree of serpentinization, as well as metasomatic talc-amphibole-chlorite overprinting and local rodingitization. Metasomatism postdates an early phase of serpentinization but predates late-stage intrusion and alteration of dolerite dikes and the extrusion of basalt. The intensity of alteration is generally lower in the gabbroic and doleritic rocks. Chilled margins in dolerite intruded into talc-amphibole-chlorite schists are observed at the most eastern Site M0075. Deformation in Expedition 357 cores is variable and dominated by brecciation and formation of localized shear zones; the degree of carbonate veining was lower than anticipated. All types of variably altered and deformed ultramafic and mafic rocks occur as components in sedimentary breccias and as fault scarp rubble. The sedimentary cap rocks include basaltic breccias with a carbonate sand matrix and/or fossiliferous carbonate. Fresh glass on basaltic components was observed in some of the breccias. The expedition also successfully applied new technologies, namely (1) extensively using an in situ sensor package and water sampling system on the seabed drills for evaluating real-time dissolved oxygen and methane, pH, oxidation-reduction potential (ORP), temperature, and conductivity during drilling; (2) deploying a borehole plug system for sealing seabed drill boreholes at four sites to allow access for future sampling; and (3) proving that tracers can be delivered into drilling fluids when using seabed drills. The rock drill sensor packages and water sampling enabled detection of elevated dissolved methane and hydrogen concentrations during and/or after drilling, with “hot spots” of hydrogen observed over Sites M0068–M0072 and methane over Sites M0070–M0072. Shipboard determination of contamination tracer delivery confirmed appropriate sample handling procedures for microbiological and geochemical analyses, which will aid all subsequent microbiological investigations that are part of the science party sampling plans and will verify this new tracer delivery technology for seabed drill rigs. Shipboard investigation of biomass density in select samples revealed relatively low and variable cell densities, and enrichment experiments set up shipboard reveal growth. Thus, we anticipate achieving many of the deep biosphere–related objectives of the expedition through continued scientific investigation in the coming years. Finally, although not an objective of the expedition, we were serendipitously able to generate a high-resolution (20 m per pixel) multibeam bathymetry map across the entire Atlantis Massif and the nearby fracture zone, MAR, and eastern conjugate, taking advantage of weather and operational downtime. This will assist science party members in evaluating and interpreting tectonic and mass-wasting processes at Atlantis Massif

    Eastern sites. Atlantis Massif: Serpentinisation and life

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    International Ocean Discovery Program (IODP) Expedition 357 successfully cored an east–west transect across the southern wall of Atlantis Massif on the western flank of the Mid-Atlantic Ridge (MAR) to study the links between serpentinization processes and microbial activity in the shallow subsurface of highly altered ultramafic and mafic sequences that have been uplifted to the seafloor along a major detachment fault zone. The primary goals of this expedition were to (1) examine the role of serpentinization in driving hydrothermal systems, sustaining microbial communities, and sequestering carbon; (2) characterize the tectonomagmatic processes that lead to lithospheric heterogeneities and detachment faulting; and (3) assess how abiotic and biotic processes change with variations in rock type and progressive exposure on the seafloor. To accomplish these objectives, we developed a coring and sampling strategy centered on the use of seabed drills—the first time that such systems have been used in the scientific ocean drilling programs. This technology was chosen in the hope of achieving high recovery of the carbonate cap sequences and intact contact and deformation relationships. The expedition plans also included several engineering developments to assess geochemical parameters during drilling; sample bottom water before, during, and after drilling; supply synthetic tracers during drilling for contamination assessment; acquire in situ electrical resistivity and magnetic susceptibility measurements for assessing fractures, fluid flow, and extent of serpentinization; and seal boreholes to provide opportunities for future experiments. Seventeen holes were drilled at nine sites across Atlantis Massif, with two sites on the eastern end of the southern wall (Sites M0068 and M0075), three sites in the central section of the southern wall north of the Lost City hydrothermal field (Sites M0069, M0072, and M0076), two sites on the western end (Sites M0071 and M0073), and two sites north of the southern wall in the direction of the central dome of the massif and Integrated Ocean Drilling Program Site U1309 (Sites M0070 and M0074). Use of seabed drills enabled collection of more than 57 m of core, with borehole penetration ranging from 1.30 to 16.44 meters below seafloor and core recoveries as high as 74.76% of total penetration. This high level of recovery of shallow mantle sequences is unprecedented in the history of ocean drilling. The cores recovered along the southern wall of Atlantis Massif have highly heterogeneous lithologies, types of alteration, and degrees of deformation. The ultramafic rocks are dominated by harzburgites with intervals of dunite and minor pyroxenite veins, as well as gabbroic rocks occurring as melt impregnations and veins, all of which provide information about early magmatic processes and the magmatic evolution in the southernmost portion of Atlantis Massif. Dolerite dikes and basaltic rocks represent the latest stage of magmatic activity. Overall, the ultramafic rocks recovered during Expedition 357 reveal a high degree of serpentinization, as well as metasomatic talc-amphibole-chlorite overprinting and local rodingitization. Metasomatism postdates an early phase of serpentinization but predates late-stage intrusion and alteration of dolerite dikes and the extrusion of basalt. The intensity of alteration is generally lower in the gabbroic and doleritic rocks. Chilled margins in dolerite intruded into talc-amphibole-chlorite schists are observed at the most eastern Site M0075. Deformation in Expedition 357 cores is variable and dominated by brecciation and formation of localized shear zones; the degree of carbonate veining was lower than anticipated. All types of variably altered and deformed ultramafic and mafic rocks occur as components in sedimentary breccias and as fault scarp rubble. The sedimentary cap rocks include basaltic breccias with a carbonate sand matrix and/or fossiliferous carbonate. Fresh glass on basaltic components was observed in some of the breccias. The expedition also successfully applied new technologies, namely (1) extensively using an in situ sensor package and water sampling system on the seabed drills for evaluating real-time dissolved oxygen and methane, pH, oxidation-reduction potential (ORP), temperature, and conductivity during drilling; (2) deploying a borehole plug system for sealing seabed drill boreholes at four sites to allow access for future sampling; and (3) proving that tracers can be delivered into drilling fluids when using seabed drills. The rock drill sensor packages and water sampling enabled detection of elevated dissolved methane and hydrogen concentrations during and/or after drilling, with “hot spots” of hydrogen observed over Sites M0068–M0072 and methane over Sites M0070–M0072. Shipboard determination of contamination tracer delivery confirmed appropriate sample handling procedures for microbiological and geochemical analyses, which will aid all subsequent microbiological investigations that are part of the science party sampling plans and will verify this new tracer delivery technology for seabed drill rigs. Shipboard investigation of biomass density in select samples revealed relatively low and variable cell densities, and enrichment experiments set up shipboard reveal growth. Thus, we anticipate achieving many of the deep biosphere–related objectives of the expedition through continued scientific investigation in the coming years. Finally, although not an objective of the expedition, we were serendipitously able to generate a high-resolution (20 m per pixel) multibeam bathymetry map across the entire Atlantis Massif and the nearby fracture zone, MAR, and eastern conjugate, taking advantage of weather and operational downtime. This will assist science party members in evaluating and interpreting tectonic and mass-wasting processes at Atlantis Massif
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