971 resultados para Steamboats -- Great Lakes (North America) -- History.
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Popular articles about the Atlantic salmon (Salmo salar) usually state that ‘the Atlantic salmon is an anadromous species’, e.g. publications by the Atlantic Salmon Federation (North America), Atlantic Salmon Trust (UK), and WWF (World Wildlife Fund), and the life history is depicted as migration of juveniles from fresh water to the marine environment, with a return to where the fish were born as spawning adults. This article reviews the life history tactics of Atlantic salmon in Newfoundland.
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EXTRACT (SEE PDF FOR FULL ABSTRACT): There were many similarities between the February 1986 storm and that of December 1964 and also December 1955. The 1964 storm hit hardest a little further north and the North Coast took the brunt of that storm. December 1955 also produced higher north coastal area runoff. December 1955 produced greater peaks in the central part of the state than the 1964 flood and is perhaps more comparable south of the Lake Tahoe-American River area. But the real surprise this time was the volume. Four reservoirs, Folsom, Black Butte, Pardee, and Comanche, were filled completely and became surcharged (storing more water than the designed capacity). The 10 day total rainfall amounted to half the normal annual totals at many precipitation stations. The February 1986 flood is a vivid reminder of the extremes of California climate and the value of the extensive system of flood control works in the state. Before the storm, especially in January, there was much concern about the dryness of the water year. Then with the deluge, California's flood control systems were tested. By and large the system worked preventing untold damage and misery for most dwellers in the flat lands.
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EXTRACT (SEE PDF FOR FULL ABSTRACT): Four broad regions of the western United States within which annual streamflows exhibit strong spatial coherence are identified using principal component analysis with a varimax rotation. Geographically, the four regions encompass the Pacific Northwest, Far West-Great Basin, Central Rockies-High Plains, and Northern Great Plains. These regions are really consistent with previously documented, descriptively derived streamflow regimes as well as with general atmospheric circulation and precipitation modes of variation. Collectively, the four regional components account for nearly 63 percent of the total annual variation in western U.S. streamflow. The time history of most principal component patterns exhibit little or no persistence.
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EXTRACT (SEE PDF FOR FULL ABSTRACT): Pollen from the upper 2.75 m of a core taken 200 km west of the Golfo de Guayaquil, Ecuador (Trident 163-13, 3° S, 84° W, 3,000 m water depth) documents changes in Andean vegetation and climate of the Cordillera Occidental for ~17,000 years before and after the last glacial maximum.
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EXTRACT (SEE PDF FOR FULL ABSTRACT): The history of the El Nino phenomena is recorded in both the fluvial and coastal sediments of northern Peru. The fluvial record was presented at the 1987 PACLIM Workshop and is discussed in detail elsewhere (Wells, 1987). However, the number of radiocarbon dated El Nino events has increased since Wells (1987) was published; this data is presented in Table 1.
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http://www.archive.org/details/indianandwhite00palliala
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http://www.archive.org/details/missionspacific00eellrich
Forty years among the Indians ; a descriptive history of the long and busy life of Jeremiah Hubbard.
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http://www.archive.org/details/fortyyearsamongi00hubbrich
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http://www.archive.org/details/historyofcatholi00sheaiala
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http://www.archive.org/details/baptistindianmiss00mccorich
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The role of chromosomal inversions in adaptation and speciation is controversial. Historically, inversions were thought to contribute to these processes either by directly causing hybrid sterility or by facilitating the maintenance of co-adapted gene complexes. Because inversions suppress recombination when heterozygous, a recently proposed local adaptation mechanism predicts that they will spread if they capture alleles at multiple loci involved in divergent adaptation to contrasting environments. Many empirical studies have found inversion polymorphisms linked to putatively adaptive phenotypes or distributed along environmental clines. However, direct involvement of an inversion in local adaptation and consequent ecological reproductive isolation has not to our knowledge been demonstrated in nature. In this study, we discovered that a chromosomal inversion polymorphism is geographically widespread, and we test the extent to which it contributes to adaptation and reproductive isolation under natural field conditions. Replicated crosses between the prezygotically reproductively isolated annual and perennial ecotypes of the yellow monkeyflower, Mimulus guttatus, revealed that alternative chromosomal inversion arrangements are associated with life-history divergence over thousands of kilometers across North America. The inversion polymorphism affected adaptive flowering time divergence and other morphological traits in all replicated crosses between four pairs of annual and perennial populations. To determine if the inversion contributes to adaptation and reproductive isolation in natural populations, we conducted a novel reciprocal transplant experiment involving outbred lines, where alternative arrangements of the inversion were reciprocally introgressed into the genetic backgrounds of each ecotype. Our results demonstrate for the first time in nature the contribution of an inversion to adaptation, an annual/perennial life-history shift, and multiple reproductive isolating barriers. These results are consistent with the local adaptation mechanism being responsible for the distribution of the two inversion arrangements across the geographic range of M. guttatus and that locally adaptive inversion effects contribute directly to reproductive isolation. Such a mechanism may be partially responsible for the observation that closely related species often differ by multiple chromosomal rearrangements.
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Review of: Janis, C.M., Scott, K.M., & Jacobs, L.L. (eds.) 1998. Evolution of Tertiary Mammals of North America Volume 1: Terrestrial Carnivores, Ungulates, and Ungulatelike Mammals, i-x, 1491. Cambridge University Press, Cambridge, UK. £165
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The acorn barnacle Chthamalus montagui can present strong variation in shell morphology, ranging from flat conic to a highly bent form, caused by a substantial overgrowth of the rostrum plate. Shell shape distribution was investigated between January and May 2004 from geographical to microhabitat spatial scales along the western coast of Britain. Populations studied in the north (Scotland and Isle of Man) showed a higher degree of shell variation compared to those in the south (Wales and south-west England). In the north, C. montagui living at lower tidal levels and in proximity to the predatory dogwhelk, Nucella lapillus, were more bent in profile. Laboratory experiments were conducted to examine behavioural responses, and vulnerability of bent and conic barnacles to predation by N. lapillus. Dogwhelks did not attack one morphotype more than the other, but only 15 % of attacks on bent forms were successful compared to 75 % in conic forms. Dogwhelk effluent reduced the time spent feeding by C. montagui (11 %), but there was no significant difference between conic and bent forms. Examination of barnacle morphology indicated a trade-off in investment in shell structure and feeding appendages associated with being bent, but none with egg or somatic tissue mass. These results are consistent with C. montagui showing an induced defence comparable to that found in its congeners Chthamalus anisopoma and Chthamalus fissus on the Pacific coast of North America, but further work to demonstrate inducibility is required.
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The use of the consumer boycott as a political tool is commonly associated with pre-revolutionary colonial America and has been identified by historians as an important means through which American women were politicized. This article argues that from the late seventeenth century, Irish political discourse advocated the non-consumption of imported goods and support for home manufactures by women in ways that were strikingly similar to those used later in North America. In Ireland and, subsequently in the American colonies, the virtuous woman consumer was given an active public role by political and social commentators. Rather than being a “brilliantly original American invention,” as T. H. Breen has argued, the political exploitation of a consumer boycott and the promotion of local industry were among what Bernard Bailyn has described as the “set of ideas, already in scattered ways familiar” to the revolutionary leaders through the Irish experience. The article also argues that a shared colonial environment gave Irish and American women a public patriotic role in the period, c. 1700–1780 that they did not have in the home countries of England and Scotland.
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We describe the career of John Birks as a pioneering scientist who has, over a career spanning five decades, transformed palaeoecology from a largely descriptive to a rigorous quantitative science relevant to contemporary questions in ecology and environmental change. We review his influence on students and colleagues not only at Cambridge and Bergen Universities, his places of primary employment, but also on individuals and research groups in Europe and North America. We also introduce the collection of papers that we have assembled in his honour. The papers are written by his former students and close colleagues and span many of the areas of palaeoecology to which John himself has made major contributions. These include the relationship between ecology and palaeoecology, late-glacial and Holocene palaeoecology, ecological succession, climate change and vegetation history, the role of palaeoecological techniques in reconstructing and understanding the impact of human activity on terrestrial and freshwater ecosystems and numerical analysis of multivariate palaeoecological data.