A Moon-borne electromagnetic calorimeter     

Roberto Battiston  Maria Teresa Brunetti  Franco Cervelli  Cristiano Fidani  Mauro Menichelli 《Astrophysics and Space Science》2009,323(4):357-366

We discuss an electromagnetic sampling calorimeter for the detection of very high energy gamma-rays on the Moon, which is based on the use of scintillating cylinders and plates imbedded in the lunar soil. The use of lunar soil as a calorimeter radiator reduces the weight of the material to be transported to the Moon and minimises environmental impact. Plastic scintillator bars inserted into the regolith about 1.5 m are the active elements of this instrument: at the surface, each bar is terminated by a plastic scintillator plate to veto high energy charge particles. The readout system for the scintillator bars and plates are based on recently developed single photon solid state detectors (Silicon Photomultiplier, SiPM), extremely compact, sturdy and sensitive devices suited for detecting small light pulses in a space experiment. The performance of a regolith-scintillator calorimeter is evaluated and the relevant parameters are optimised using a GEANT4 simulation.  相似文献   

Does multiclustering of galaxy aggregates appear as a specific coil of extragalactic data unseparated from interpretations of the role of interstellar obscuration?     

Teresa Grabińska  Mirosław Zabierowski 《Astrophysics and Space Science》1987,137(2):403-406

The use of a cosmic potential in relativistic cosmology is criticized. It is pointed out that the energetic closure of the Universe follows from general relativity and from quantized superspace cosmology without the introduction of the cosmic potential.  相似文献   

Coastal Pollution Mitigation with Lime and Zero Valent Iron     

John L. Daniels  Gautham P. Das  Maria Teresa Serrano Hernandez  Sunyoung Bae 《Marine Georesources & Geotechnology》2006,24(3):183-191

The Taiwan Strait region has many miles of coastline, and the Taiwan Straits Tunnel (TST) project faces many potential pollution problems as construction proceeds through sensitive areas. Conventional approaches for pollution mitigation require further examination. The recent development of nanoscale particle technology has shown distinct advantages for contaminant attenuation and ground improvement. This paper is focused on trace metals and is part of the overall effort to develop the nanoscale particle technology. Trace metals in ground and surface waters represent a continued threat to human and ecological health. One of the difficulties in removing toxic concentrations of trace metals from solution is the variable oxidation state and amphoteric nature of multiple constituents. In particular, while cationic metals (e.g., Pb²⁺, Cd²⁺, Ni²⁺) may be rendered less mobile under high pH conditions, anionic metals (e.g., AsO₄^3-, CrO₄^2-, SeO₄^2-)may become more mobile. The objective of this research was to evaluate the sorption of both cationic and anionic trace elements, including arsenic (As), cadmium (Cd), chromium (Cr) and selenium (Se) under batch conditions. Mixtures of a local residual soil were tested alone and in combination with lime and zero valent iron. It was hypothesized that lime would raise the pH and precipitate positively charged metals while zero valent iron would create reducing conditions favorable to the immobilization of negatively charged metals. Results indicate that the use of lime and/or zero valent iron can increase the sorption capacity of soil. Compared to the baseline soil, sorption capacity increased with addition of lime for arsenic and cadmium while it decreased for chromium and selenium. In the case of zero valent iron addition, sorption capacity increased for cadmium, chromium and selenium, while showing no change for arsenic. When both lime and zero valent iron were used, the sorption capacity increased for all metals tested. These results suggest that the combined use of lime and zero valent iron may serve as an alternative treatment technology for removing trace metals from contaminated water systems.  相似文献   

Assessment of toxicological status of a SW Mediterranean segment population of striped dolphin (Stenella coeruleoalba) using skin biopsy     

Fossi MC  Marsili L  Lauriano G  Fortuna C  Canese S  Ancora S  Leonzio C  Romeo T  Merino R  Abad E  Jiménez B 《Marine environmental research》2004,58(2-5):269-274

Various studies have revealed high concentrations of contaminants such as organochlorines (OCs) and heavy metals in Mediterranean cetaceans. A geographical trend of contamination (PCBs and DDTs) has been found for striped dolphin (Stenella coeruleoalba). In this study we used a non-lethal approach (skin biopsy) to investigate bioaccumulation of OCs, including polychlorobiphenyls (PCBs), DDTs, polychlorodibenzo-p-dioxins (PCDDs), polychlorodibenzofurans (PCDFs), trace elements (Hg, Cd, Pb) and CYP1A activity (BPMO) in nine striped dolphins sampled in the Aeolian area (Sicily - Italy) in summer 2002. The arithmetic mean value of BPMO activity in this group was 43.46 AUF/g tissue/h. This value is approximately 3 times and 5 times lower, respectively, than the value found in the Ionian and in the Ligurian groups. Skin biopsies of striped dolphins emerged as a suitable material for assessing the toxicological status of the various Mediterranean groups.  相似文献   

Endocrine disruption in a marine amphipod? Field observations of intersexuality and de-masculinisation     

Ford AT  Fernandes TF  Rider SA  Read PA  Robinson CD  Davies IM 《Marine environmental research》2004,58(2-5):169-173

Intersexuality has been found in both males and females of the marine/estuarine amphipod, Echinogammarus marinus, at polluted and reference sites in East Scotland. Polluted sites had significantly more intersex specimens than reference sites, however the cause of intersexuality is unclear. Discriminant analysis of morphometric data showed that normal male specimens from the most polluted site resembled pooled intersex males, suggesting that subtle endocrine disruption (ED) maybe occurring in these otherwise apparently normal males. The main discriminating character was gnathopod size, recognised to be under androgenic gland control. The association of distinctive morphometry with intersexuality may provide a new approach to biomarkers of ED in crustaceans. The opportunities for other novel biomarkers, for example biochemical or behavioural markers, may also be explored through study of intersex animals.  相似文献   

Retrograde formation of NaCl-scapolite in high pressure metaevaporites from the Cordilleras Béticas (Spain)     

Maria Teresa Gómez-Pugnaire  Gerhard Franz  Vicente López Sánchez-Vizcaino 《Contributions to Mineralogy and Petrology》1994,116(4):448-461

A Permo-Triassic pelite-carbonate rock series (with interacalated metabasitic rocks) in the Cordilleras Béticas, Spain, was metamorphosed during the Alpine metamorphism at high pressures (P _min near 18 kbar). The rocks show well preserved sedimentary features of evaporites such as pseudomorphs of talc, of kyanite-phengitetalc-biotite, and of quartz after sulfate minerals, and relicts of baryte, anhydrite, NaCl, and KCl, indicating a salt-clay mixture of illite, chlorite, talc, and halite as the original rock. The evaporitic metapelites have a whole rock composition characterized by high Mg/(Mg+Ca) ratios>0.7, variable alkaline and Sr, Ba, contents, but are mostly K₂O rich (<8.8 wt%). The F (<2600 ppm), Cl (<3600 ppm), and P₂O₅ (<0.24 wt%) contents are also high. The pelitic member of this series is a fine grained biotite rock. Kyanite-phengite-talc-biotite aggregates in pseudomorphs developed in the high pressure stage. Albite-rich plagioclase was formed when the rocks crossed the albite stability curve in the early stages of the uplift. Scapolite, rich in NaCl (Ca/(Ca+Na) mol% 24–40) and poor in SO₄, with Cl/(Cl+CO₃) ratios between 0.6 and 0.8, formed as porphyroblasts, sometimes replacing up to 60% of the rock in a late stage of metamorphism (between 10 and 5 kbar, near 600°C). No reaction with albite is observed, and the scapolite formed from biotite by: $$\begin{gathered} Al - biotite + CaCO_3 + NaCl + SiO_2 \hfill \\ = Al - poor biotite + scapolite + MgCO_3 + KCl \hfill \\ + MgCl_2 + H_2 O \hfill \\ \end{gathered}$$ Calculated fluid composition in equilibrium with scapolite indicates varying salt concentrations in the fluid. Distribution of Cl and F in biotite and apatite also indicates varying fluid compositions.  相似文献   

Recent observations of the WR central star of the planetary nebula LMC-N66     

Miriam Peña  Manuel Peimbert  Silvia Torres-Peimbert  Maria Teresa Ruiz  Jose Maza 《Astrophysics and Space Science》1996,238(1):55-58

The recent evolution of the central star of the planetary nebula LMC-N66 is presented. Before 1987, it showed a weak continuum with aT _eff120 000 K andL _bol25 000L and in a few years it developed strong WR features (P Cygni line profiles in N v at 124.0 nm and C IV at 155.0 nm, wide Heii emission, etc.) typical of a WN 4.5. Additionally the stellar continuum increased by a large factor and the absolute visual magnitude of the star changed from + 1.24 in 1987 to–2.57 in January, 1995. The WR features and enhanced continuum, evidencing a powerful mass-loss event remained with small variations for more than 5 years. Recent ultraviolet and optical data shows that the mass-loss seems to have diminished abruptly in the last three months.  相似文献   

Space-time analysis of the relative local secular variations of the geomagnetic field (1966–2005) along the Zgorzelec-Wiżajny profile     

Grzegorz Bojdys  Teresa Grabowska 《Acta Geophysica》2007,55(2):169-181

The Zgorzelec-Wiżajny profile cuts through the main European geotectonic units of the Palaeozoic Western and Central European Platform and the East European Craton, including the connecting Trans-European Suture Zone. The paper summarises 40 years of research on geomagnetic secular variations along the Zgorzelec-Wiżajny profile since 1966. It discusses methods of processing measurement records and presenting their results. The latter are presented against the background of the local geology and the crustal deep magnetic structure data. The hitherto method of variation analysis was modified to address a new trend in the geomagnetic secular variations that has emerged in the East European Craton during the last five years (2001–2005).  相似文献   

Fortresses of desire: Melrose Arch and the emergence of urban tourist spectacles     

Teresa Dirsuweit  Florian Schattauer 《GeoJournal》2004,60(3):239-247

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Chemical evolution of mid-ocean ridge hot springs     

Teresa Suter Bowers  Karen L. Von Damm  John M. Edmond 《Geochimica et cosmochimica acta》1985,49(11):2239-2252

Chemical analyses yielding elemental concentrations of major and minor elements of four hot springs on the East Pacific Rise at 21°N and 10 hot springs from the southern trough of the Guaymas Basin, Gulf of California provide a basis for thermodynamic modeling of conductive cooling of the hydrothermal endmembers, mixing of the hydrothermal endmember with seawater, and reaction of an EPR-type fluid with sediment of bulk chemical composition corresponding to unaltered sediment from DSDP hole 477 in the Guaymas Basin. Results of the calculations indicate that conductive cooling of endmember fluids within closed chimneys and conduits accounts for the solution composition of one vent on the East Pacific Rise and several vents in Guaymas Basin. Mixing of the hydrothermal fluids with seawater yields a prediction of mineral assemblages closely approximating those observed in samples of chimneys from the East Pacific Rise and drill cores in Guaymas Basin. The hypothesis that Guaymas Basin hydrothermal fluids result from interaction of an EPR-type fluid with sediment cover in Guaymas Basin is supported by calculations which predict an increase in pH to a value similar to Guaymas Basin fluids, an order-of-magnitude decrease in metal concentrations, and an excellent agreement between predicted mineral assemblages as a function of extent of interaction with sediment, and observed mineral assemblage distribution with depth.  相似文献