2,013 research outputs found
Linking individual behaviour to community scale patterns in fungi
The fungi comprise a separate kingdom of life and epitomise the indeterminate growth form. Very little is known about the factors that influence the nature of fungal diversity and the link between individual behaviour and the structure and function of fungal communities is particularly poorly understood. Here, we present a theoretical framework that is capable of elucidating this link. An individual-based model for fungal community dynamics is introduced that has been developed from a physiologically based model for the fungal phenotype. The model is used to explore the role of individual interactions, the production of an external inhibitor field and the quality of the external environment on the structure and diversity of the resulting community. We show that traits relating to growth rate, autophagic behaviour and the production of inhibitors are key in influencing the success of a particular genotype in a community. The species richness increases with the amount of available resource. This is the first model of fungal community dynamics that introduces the concept of a biomass-based abundance distribution function that can be described by the log-normal form which typically corresponds to communities in equilibrium. The species abundance curve was stable to changes in the relative location of inocula, although the ranked abundance of the individuals was not. We present the first attempt to identify the traits that affect the form of that curve. Future studies should examine the role of environmental heterogeneity and spore dispersal
Space shuttle three main engine return to launch site abort
A Return-to-Launch-Site (RTLS) abort with three Space Shuttle Main Engines (SSME) operational was examined. The results are trajectories and main engine cutoff conditions that are approximately the same as for a two SSME case. Requiring the three SSME solution to match the two SSME abort eliminates additional crew training and is accomplished with negligible software impact
U.S. antidumping: much ado about zeroing
The United States use of"zeroing"in its antidumping procedures has become a political flash point threatening some legitimacy of the WTO's dispute settlement system. This paper provides a positive analysis of the zeroing issue, explains how it has evolved and who is likely to be affected by it. The authors use economic theory to identify how export price volatility accentuates the impact of zeroing on the size of U.S. antidumping tariffs and review the WTO caseload over zeroing. They describe the impact that the U.S.'s retrospective system for assessing antidumping margins has on zeroing and the political economy implications as the U.S. struggles to generate policy reform. The authors survey existing evidence of the impact of the zeroing on dumping margins and contribute their own evidence to suggest that zeroing is just as likely to impact the size of U.S. antidumping duties applied on developing country exportsas developed economy exports. Thus while developed economies have filed the vast majority of WTO disputes against the U.S. over zeroing, the authors conclude that zeroing is also likely a relevant issue for developing country exporters as over 60 percent of the product lines currently subject to U.S. antidumping are exported by developing countries.Markets and Market Access,Economic Theory&Research,Trade Law,Access to Markets,Emerging Markets
Deedee And The Dove
In lieu of an abstract, below is the essay\u27s first paragraph.
On Saturday mornings, DeeDee goes to the open market to buy clothes for Sra. Paloma. DeeDee lives in a dark brick building on Suffolk St., near Peretz Square, in lower Manhattan. Sra. Paloma lives across from her in a wan green tenement that has been swept by fire. Her walls are charred and blackened with soot, her floors sag from water damage, and her furniture - still soaked from the firemen\u27s hoses - has sprouted mildew. It is rumored around the neighborhood that every morning the Senora scours her furniture in her dark fury, but the mildew always returns in a ghostly fashion
Early Cretaceous biogeographic and oceanographic synthesis of Leg 123 (off Northwestern Australia)
Biogeographic observations made by Leg 123 shipboard paleontologists for Lower Cretaceous nannofossils, foraminifers,
radiolarians, belemnites, and inoceramids are combined in this chapter to evaluate the paleoceanographic history
of the northwestern Australian margin and adjacent basins. Each fossil group is characterized at specific intervals of
Cretaceous time and compared with data from Tethyan and Southern Hemisphere high-latitude localities. Special attention
is given to the biogeographic observations made for the Falkland Plateau (DSDP Legs 36 and 71) and the Weddell Sea
(ODP Leg 113). Both areas have yielded valuable Lower Cretaceous fossil records of the circumantarctic high latitudes.
In general, the Neocomian fossil record from DSDP and ODP sites off northwestern Australia has important southern
high-latitude affinities and weak Tethyan influence. The same is true for the pelagic lithofacies: radiolarian chert and/or
nannofossil limestone, dominant in the Tethyan Lower Cretaceous, are minor lithologies in the Exmouth-Argo sites.
These observations, together with the young age of the Argo crust and plate tectonic considerations, suggest that the Argo
Basin was not part of the Tethys Realm.
The biogeography of the Neocomian radiolarian and nannofossil assemblages suggests opening of a seaway during
the Berriasian that connected the circumantarctic area with the Argo Basin, which resulted in the influx of southern
high-latitude waters.
This conclusion constrains the initial fit and break-up history of Gondwana. Our results favor the loose fit of the
western Australian margin with southeast India by Ricou et al. (1990), which accounts for a deeper water connection with
the Weddell-Mozambique basins via drowned marginal plateaus as early as the Berriasian. In fits of the du Toit-type
(1937), India would remain attached to Antarctica, at least until the late Valanginian, making such a connection
impossible.
After the Barremian, increasing Tethyan influence is evident in all fossil groups, although southern high-latitude taxa
are still present. Biogeographic domains, such as the southern extension of Nannoconus and Ticinella suggest paleolatitudes
of about 50°S for the Exmouth-Argo area. Alternatively, if paleolatitudes of about 35° are accepted, these
biogeographic limits were displaced northward at least 15° along Australia in comparison to the southern Atlantic. In this
case, the proto-circumantarctic current was deflected northward into an eastern boundary current off Australia and carried
circumantarctic cold water into the middle latitudes.
Late Aptian/early Albian time is characterized by mixing of Tethyan and southern faunal elements and a significant
gradient in Albian surface-water temperatures over 10° latitude along the Australian margin, as indicated by planktonic
foraminifers. Both phenomena may be indicative of convergence of temperate and antarctic waters near the Australian
margin. High fertility conditions, reflected by radiolarian cherts, are suggestive of coastal upwelling during that time
The U.S. trade deficit: made in China?
Rapid growth of the U.S. bilateral trade deficit with China has promoted a widespread view that the overall trade deficit is "made in China." The authors examine the probable consequences of increased protection directed toward U.S. imports from China. Their appraisal of recent and prospective U.S. trade policy focuses on textiles and apparel—sectors where the growth of imports from China has been prominent. They also consider the likely effects of yuan appreciation on the bilateral and overall trade deficits.Balance of trade ; Balance of trade - China
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