Oxygen and bulk element abundances in Luna 20 fines

Abundances of O, Si, Al and Mn have been determined in Luna 20 fines sample 22001,9 by instrumental neutron activation analysis. The abundances of O, Si and Al are among the highest we have observed in lunar samples and reflect a highlands origin for much of this regolith sample. The Luna 20 abundances reported here most closely resemble those we have determined in four samples of two Apollo 16 fines, rock 14310, and a clast from breccia 15459. The Luna 20 $\text{O}\text{Si}$ ratio of 1.96 ± 0.05 is similar to that in most other lunar samples, but the $\text{Al}\text{Si}$ ratio of 0.532 ± 0.024 is exceeded only by our data on the Apollo 16 fines. This $\text{Al}\text{Si}$ ratio is in agreement with the value of 0.55 ± 0.06 determined by the remote X-ray fluorescence experiment for the highlands between Mare Crisium and Mare Smythii which lie near the Luna 20 site (Adleret al., 1972).     

Behavior of lophophorates during the end-Permian mass extinction and recovery

The end-Permian mass extinction devastated most marine communities and the recovery was a protracted event lasting several million years into the Early Triassic. Environmental and biological processes undoubtedly controlled patterns of recovery for marine invertebrates in the aftermath of the extinction, but are often difficult to single-out. The global diversity and distribution of marine lophophorates during the aftermath of the end-Permian mass extinction indicates that stenolaemate bryozoans, rhynchonelliform brachiopods, and lingulid brachiopods displayed distinct recovery patterns.Bryozoans were the most susceptible of the lophophorates, experiencing relatively high rates of extinction at the end of the Permian, and becoming restricted to the Boreal region during the Early Triassic. The recovery of bryozoans was also delayed until the Late Triassic and characterized by very low diversity and abundance. Following the final disappearance of Permian rhynchonelliform brachiopod survivors, Early Triassic rhynchonelliform brachiopod abundance remained suppressed despite a successful re-diversification and a global distribution, suggesting a decoupling between global taxonomic and ecological processes likely driven by lingering environmental stress.In contrast with bryozoans and rhynchonelliforms, lingulid brachiopods rebounded rapidly, colonizing shallow marine settings left vacant by the extinction. Lingulid dominance, characterized by low diversity but high numerical abundance, was short-lived and they were once again displaced back into marginal settings as environmental stress changed through the marine recovery. The presence in lingulid brachiopods of the respiratory pigment hemerythrin, known to increase the efficacy of oxygen storage and transport, when coupled with other morphological and physiological adaptations, may have given lingulids a survival advantage in environmentally stressed Early Triassic settings.     

Sedimentary characteristics of paleo-aeolian dune sands of Salawusu Formation in the Salawusu River Valley

The Salawusu Formation of Milanggouwan section in Salawusu River Valley in-cludes 7 layers of paleo-mobile dune sands, and 4 layers of paleo-fixed and semi-fixed dune sands. Their structures have been observed and their grain size, surface textural features and several main chemical elements have been analyzed. The results showed that: 1) Some of the aeolian structural characteristics of these dune sands are similar to that of the recent dune sands. 2) They are also similar to the recent dune sands in grain size components, and parameters of Mz, σ, Sk and Kg, as well as in several main chemical components. 3) The scattergrams of Mz-σ and SiO2–Al2O3+TOFE and the probability curves of grain size showed that these paleo-dune sands are different from paleosols and fluvio-lacustrine facies, but are consistency with recent dune sands. 4) Quartz sands have well roundness and surface textural features such as dish-shaped pits, crescent-shaped pits, pockmarked pits, upturned cleavage plates, siliceous precipitates and siliceous crevasses, indicating that they had been carried for a long time by the wind. As the 11 layers of paleo-dune sands possess the aeolian characteristics in structure, grain size, surface textural features and chemical elements, the origin of their formation should be attributed to eolation.     

美国罗德河流域地下水中铝形成动力学

In the Rhode River estuarine/watershed area, increased acidity of precipitation from atmospheric acidic deposition has deleterious effects on the freshwater ecosystems. One of the characteristics of an acidic watershed is the mobilization of aluminum from soils to aquatic environment. Increased concentrations of aluminum in surface waters are toxic to living organisms. Detection of long-term changes of acidity and elevated Al concentrations in surface and soil waters is a central issue. In this present paper, the dynamics ofAl speciation in the shallow ground waters from Rhode River watershed 110 (la) were investigated. This research provides a unique, regional analysis of important controls on the transport of Al speciation through the rural watershed of the Chesapeake Bay.     

Oceanography of Glacier Bay,Alaska: Implications for biological patterns in a glacial fjord estuary

Alaska, U.S.A, is one of the few remaining locations in the world that has fjords that contain temperate idewater glaciers. Studying such estuarine systems provides vital information on how deglaciation affects oceanographic onditions of fjords and surrounding coastal waters. The oceanographic system of Glacier Bay, Alaska, is of particular interest ue to the rapid deglaciation of the Bay and the resulting changes in the estuarine environment, the relatively high oncentrations of marine mammals, seabirds, fishes, and invertebrates, and the Bay’s status as a national park, where ommercial fisheries are being phased out. We describe the first comprehensive broad-scale analysis of physical and iological oceanographic conditions within Glacier Bay based on CTD measurements at 24 stations from 1993 to 2002. easonal patterns of near-surface salinity, temperature, stratification, turbidity, and euphotic depth suggest that freshwater nput was highest in summer, emphasizing the critical role of glacier and snowmelt to this system. Strong and persistent tratification of surface waters driven by freshwater input occurred from spring through fall. After accounting for seasonal nd spatial variation, several of the external physical factors (i.e., air temperature, precipitation, day length) explained a large mount of variation in the physical properties of the surface waters. Spatial patterns of phytoplankton biomass varied hroughout the year and were related to stratification levels, euphotic depth, and day length. We observed hydrographic atterns indicative of strong competing forces influencing water column stability within Glacier Bay: high levels of freshwater ischarge promoted stratification in the upper fjord, while strong tidal currents over the Bay’s shallow entrance sill enhanced ertical mixing. Where these two processes met in the central deep basins there were optimal conditions of intermediate tratification, higher light levels, and potential nutrient renewal. These conditions were associated with high and sustained hlorophylla levels observed from spring through fall in these zones of the Bay and provide a framework for understanding he abundance patterns of higher trophic levels within this estuarine system.     

Summer interactions between weather regimes and surface ocean in the North-Atlantic region

This study aims at understanding the summer ocean-atmosphere interactions in the North Atlantic European region on intraseasonal timescales. The CNRMOM1d ocean model is forced with ERA40 (ECMWF Re-Analysis) surface fluxes with a 1-h frequency in solar heat flux (6 h for the other forcing fields) over the 1959–2001 period. The model has 124 vertical levels with a vertical resolution of 1 m near the surface and 500 m at the bottom. This ocean forced experiment is used to assess the impact of the North Atlantic weather regimes on the surface ocean. Composites of sea surface temperature (SST) anomalies associated with each weather regime are computed and the mechanisms explaining these anomalies are investigated. Then, the SST anomalies related to each weather regime in the ocean-forced experiment are prescribed to the ARPEGE Atmosphere General Circulation Model. We show that the interaction with the surface ocean induces a positive feedback on the persistence of the Blocking regime, a negative feedback on the persistence of the NAO-regime and favours the transition from the Atlantic Ridge regime to the NAO-regime and from the Atlantic Low regime toward the Blocking regime.     

Non-parametric star formation histories for four dwarf spheroidal galaxies of the Local Group

We use recent Hubble Space Telescope colour–magnitude diagrams of the resolved stellar populations of a sample of local dSph galaxies (Carina, Leo I, Leo II and Ursa Minor) to infer the star formation histories of these systems, SFR ( t ). Applying a new variational calculus maximum likelihood method, which includes a full Bayesian analysis and allows a non-parametric estimate of the function one is solving for, we infer the star formation histories of the systems studied. This method has the advantage of yielding an objective answer, as one need not assume a priori the form of the function one is trying to recover. The results are checked independently using Saha's W statistic. The total luminosities of the systems are used to normalize the results into physical units and derive SN type II rates. We derive the luminosity-weighted mean star formation history of this sample of galaxies.     

Uncertainty analysis of urban sewer system using spatial simulation of radar rainfall fields: New York City case study

The goal of this study is to investigate the uncertainty of an urban sewer system’s response under various rainfall and infrastructure scenarios by applying a recently developed nonparametric copula-based simulation approach to extreme rainfall fields. The approach allows for Monte Carlo simulation of multiple variables with differing marginal distributions and arbitrary dependence structure. The independent and identically distributed daily extreme rainfall events of the corresponding urban area, extracted from nationwide high resolution radar data stage IV, are the inputs of the spatial simulator. The simulated extreme rainfall fields were used to calculate excess runoff using the Natural Resources Conservation Service’s approach. New York City is selected as a case study and the results highlight the importance of preserving the spatial dependence of rainfall fields between the grids, even for simplified hydrologic models. This study estimates the probability of combined sewer overflows under extreme rainfall events and identifies the most effective locations in New York City to install green infrastructure for detaining excess stormwater runoff. The results of this study are beneficial for planners working on stormwater management and the approach is broadly applicable because it does not rely on extensive sewer system information.