Invertebrates of the relict steppe ecosystems of Beringia,and the reconstruction of Pleistocene landscapes     

Daniil Berman  Arcady Alfimov  Svetlana Kuzmina 《Quaternary Science Reviews》2011,30(17-18):2200-2219

Studies of invertebrates from steppe patches in the tundra and taiga zones of Beringia provide additional evidence that these areas could be relict steppes. A number of insect species common to both modern relict steppes and fossil Beringian insect faunal assemblages have been found. These provide important information on the moisture and temperature preferences of some of the surviving members of Pleistocene steppe-tundra insect communities. The most significant species of West Beringian insects are weevils in the genus Stephanocleonus (Coleoptera, Curculionidae), indicators of thermophytic steppe, and the pill beetle Morychus viridis (Coleoptera, Byrrhidae), the indicator of hemicryophytic steppe. The East Beringian invertebrate population of relict steppe is substantially different. Fossil evidence suggests that biotic exchange between the two parts of Beringia was limited during the Pleistocene; populations of steppe insects did not move across the Bering Land Bridge (BLB), while tundra species had more flexibility. The tundra environment reconstructed for the Pleistocene BLB should have facilitated amphi-beringian distributions for most tundra invertebrate species, but apparently only a few species achieved this.  相似文献   

Mise en évidence expérimentale des facteurs nutritifs limitants de la production du micro-nanoplancton et de l'ultraplancton dans une eau côtière de la Méditerranée orientale (Haïfa,Israël)     

D. J. Bonin  M. C. Bonin  T. Berman 《Aquatic Sciences - Research Across Boundaries》1989,51(2):129-152

Enrichment experiments were carried out on seawater samples from the Israeli coast to characterise the nature of nutrient limitation. Phytoplankton chlorophyll, ATP, PC, PN, PP and bicarbonate and orthophosphate uptake rates indicate that phosphorus limitation is more extreme than that of nitrogen. A large increase in total nitrogen observed with P enrichment suggests that a substantial nitrogen fixation is mediated by picocyanobacteria in this kind of oligotrophic mediterranean waters.

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An intercomparison of seawater filtration procedures     

J.M. Bewers  P.A. Yeats  S. Westerlund  B. Magnusson  D. Schmidt  H. Zehle  S.S. Berman  A. Mykytiuk  J.C. Duinker  R.F. Nolting  R.G. Smith  H.L. Windom 《Marine pollution bulletin》1985,16(7):277-281

Filtration systems, used for the preparation of coastal seawater samples for trace analysis, have been intercompared to determine the extent of contamination arising during the filtration process. The results show that all the systems intercompared are able to provide uncontaminated filtrates for copper, nickel, cobalt and manganese and, with two exceptions, for cadmium and iron, at levels that would be encountered in uncontaminated coastal waters.  相似文献   

Reassessment of the garnet-clinopyroxene Fe−Mg exchange thermometer: II. Thermodynamic analysis     

R. G. Berman  L. Ya Aranovich  D. R. M. Pattison 《Contributions to Mineralogy and Petrology》1995,119(1):30-42

 The garnet (Grt)-clinopyroxene (Cpx) Fe-Mg exchange thermometer has been re-evaluated through analysis of phase equilibrium experiments defining the Fe-Mg exchange between Grt and Cpx, Grt and Ol (Ol=Olivine), and Cpx and Ol, together with thermophysical and other phase equilibrium constraints on solid solution and individual end-member properties. Results show that all data are mutually compatible if the heterogeneity range of Grt and Cpx in run products previously obtained by Pattison and Newton (PN) are accounted for in assessing equilibrium Grt-Cpx compositions. Derived mixing properties are in good agreement with results from numerous recent phase equilibrium studies. Application of the newly calibrated thermometer to a number of amphibolite to granulite facies terrains indicates temperatures between 70 and 200 ° C above PN’s thermometer, and general compatibility with independent temperature estimates. Received: 3 September 1993 / Accepted: 16 June 1994  相似文献   

Hypoxic events in Narragansett Bay, Rhode Island, during the summer of 2001   总被引：1，自引：0，他引：1  

D. Christopher Melrose  Candace A. Oviatt  Mark S. Berman 《Estuaries and Coasts》2007,30(1):47-53

Bottom water hypoxic events were observed in Narragansett Bay, Rhode Island during the summer of 2001 using a towed sensor, vertical casts at fixed stations, and continuous monitoring buoys. This combination of approaches allowed for both extensive spatial and temporal sampling. Oxygen concentrations below the U.S. Environmental Protection Agency (EPA) acute hypoxia criterion of 2.3 mg l^?1 were observed in the northern parts of Narragansett Bay, including the Providence River. We estimate 39% of the area of the Providence River was affected by acute hypoxia between July and September 2001. All other regions experienced only small areas of acute hypoxia (<5%), and no acute hypoxia was observed from Quonset Point south. The area encompassing oxygen concentrations below the EPA chronic hypoxia criterion of 4.8 mg l^?1 was much more extensive in the upper half of Narragansett Bay, sometimes covering the majority of the region, though it is unclear whether exposure to concentrations below this criterion persisted long enough to significantly affect marine species in these areas. Vertical profiles of dissolved oxygen typically exhibited a mid water oxygen minimum near the pycnocline, followed by a slight increase in oxygen with depth. The surface waters above the pycnocline were typically supersaturated with oxygen. The northern portions of the Bay where the most extensive hypoxia was observed corresponded to the regions with both the greatest thermohaline stratification, the highest nutrient inputs, and the highest primary productivity.  相似文献   

Natural entropy production in an inflationary model for a polarized vacuum     

Marcelo Samuel Berman  Murari M. Som 《Astrophysics and Space Science》2007,310(3-4):277-279

Though entropy production is forbidden in standard FRW Cosmology, Berman and Som presented a simple inflationary model where entropy production by bulk viscosity, during standard inflation without ad hoc pressure terms can be accommodated with Robertson–Walker’s metric, so the requirement that the early Universe be anisotropic is not essential in order to have entropy growth during inflationary phase, as we show. Entropy also grows due to shear viscosity, for the anisotropic case. The intrinsically inflationary metric that we propose can be thought of as defining a polarized vacuum, and leads directly to the desired effects without the need of introducing extra pressure terms.  相似文献   

The two pioneers anomalies and universal rotation     

Marcelo Samuel Berman 《Astrophysics and Space Science》2011,336(2):337-339

We show how to prove the two Pioneers Anomalies by means of the Godlowski et al. (, 2004) idea for a rotating General Relativistic Universe. The so-called clock effect is calculated.  相似文献   

On the variability of seasonal temperature in southern South America     

Ana Laura Berman  Gabriel Silvestri  Rosa Compagnucci 《Climate Dynamics》2013,40(7-8):1863-1878

The aim of this paper is to investigate different aspects of the seasonal-to-interannual temperature variability in Eastern Patagonia, the southernmost area of South America, east of the Andes Cordillera. Homogenous regions of seasonal variability and the atmospheric circulation patterns associated with warm and cold conditions in each of them are described in this study. Relationships between temperature in Eastern Patagonia and that registered in other areas of southern South America are also addressed. Results show that the northern and southern areas of Eastern Patagonia have different temperature variability in summer and autumn whereas the temperature variability tends to be more homogeneous within the region during winter and spring. Warm (cold) conditions in the northern areas are associated with reinforced (weakened) westerlies in summer, winter and spring whereas northerly (southerly) advections of warm (cold) air toward the region produce such conditions in autumn. Temperature in the southern portion of Eastern Patagonia is affected by anticyclonic (cyclonic) anomalies that enhance (reduce) the incoming solar radiation and induce reinforced (weakened) westerlies promoting warm (cold) conditions in the region. Furthermore, cyclonic (anticyclonic) anomalies at subpolar latitudes hinder (favor) outbreaks of cold air increasing (decreasing) the temperature over areas of Eastern Patagonia. The circulation anomalies associated with warm (cold) conditions in Eastern Patagonia also promote cold (warm) conditions over areas of northern Argentina, Paraguay and southern Brazil. Consequently, a dipole of temperature is detected in southern South America with centers of opposite sign over these regions.  相似文献   

Lambda-universe in scalar-tensor gravity     

Marcelo Samuel Berman 《Astrophysics and Space Science》2009,323(1):103-106

We present a lambda-Universe, in scalar-tensor gravity, reviewing Berman and Trevisan’s inflationary case (Berman and Trevisan in Int. J. Theor. Phys., 2009) and then we find a solution for an accelerating power-law scale-factor. The negativity of cosmic pressure implies acceleration of the expansion, even with Λ<0. The cosmological term, and the coupling “constant”, are in fact, time-varying.   相似文献   

Estimating economic losses of midrise reinforced concrete shear wall buildings in sedimentary basins by combining empirical and simulated seismic hazard characterizations     

Pouria Kourehpaz  Carlos Molina Hutt  Nasser A. Marafi  Jeffrey W. Berman  Marc O. Eberhard 《地震工程与结构动力学》2021,50(1):26-42

Studies of recorded ground motions and simulations have shown that deep sedimentary basins can greatly increase the intensity of earthquake ground motions within a period range of approximately 1–4 s, but the economic impacts of basin effects are uncertain. This paper estimates key economic indicators of seismic performance, expressed in terms of earthquake‐induced repair costs, using empirical and simulated seismic hazard characterizations that account for the effects of basins. The methodology used is general, but the estimates are made for a series of eight‐ to 24‐story residential reinforced concrete shear wall archetype buildings in Seattle, WA, whose design neglects basin effects. All buildings are designed to comply with code‐minimum requirements (i.e., reference archetypes), as well as a series of design enhancements, which include (a) increasing design forces, (b) decreasing drift limits, and (c) a combination of these strategies. As an additional reference point, a performance‐based design is also assessed. The performance of the archetype buildings is evaluated for the seismic hazard level in Seattle according to the 2018 National Seismic Hazard Model (2018 NSHM), which explicitly considers basin effects. Inclusion of basin effects results in an average threefold increase in annualized losses for all archetypes. Incorporating physics‐based ground motion simulations to represent the large‐magnitude Cascadia subduction interface earthquake contribution to the hazard results in a further increase of 22% relative to the 2018 NSHM. The most effective of the design strategies considered combines a 25% increase in strength with a reduction in drift limits to 1.5%.  相似文献