993 resultados para Niagara-on-the-Lake -- History


Relevância:

100.00% 100.00%

Publicador:

Resumo:

A significant desert dust deposition event occurred on Mt. Elbrus, Caucasus Mountains, Russia on 5 May 2009, where the deposited dust later appeared as a brown layer in the snow pack. An examination of dust transportation history and analysis of chemical and physical properties of the deposited dust were used to develop a new approach for high-resolution “provenancing” of dust deposition events recorded in snow pack using multiple independent techniques. A combination of SEVIRI red-green-blue composite imagery, MODIS atmospheric optical depth fields derived using the Deep Blue algorithm, air mass trajectories derived with HYSPLIT model and analysis of meteorological data enabled identification of dust source regions with high temporal (hours) and spatial (ca. 100 km) resolution. Dust, deposited on 5 May 2009, originated in the foothills of the Djebel Akhdar in eastern Libya where dust sources were activated by the intrusion of cold air from the Mediterranean Sea and Saharan low pressure system and transported to the Caucasus along the eastern Mediterranean coast, Syria and Turkey. Particles with an average diameter below 8 μm accounted for 90% of the measured particles in the sample with a mean of 3.58 μm, median 2.48 μm. The chemical signature of this long-travelled dust was significantly different from the locally-produced dust and close to that of soils collected in a palaeolake in the source region, in concentrations of hematite. Potential addition of dust from a secondary source in northern Mesopotamia introduced uncertainty in the “provenancing” of dust from this event. Nevertheless, the approach adopted here enables other dust horizons in the snowpack to be linked to specific dust transport events recorded in remote sensing and meteorological data archives.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

A significant desert dust deposition event occurred on Mt. Elbrus, Caucasus Mountains, Russia on 5 May 2009, where the deposited dust later appeared as a brown layer in the snow pack. An examination of dust transportation history and analysis of chemical and physical properties of the deposited dust were used to develop a new approach for high-resolution provenancing of dust deposition events recorded in snow pack using multiple independent techniques. A combination of SEVIRI red-green-blue composite imagery, MODIS atmospheric optical depth fields derived using the Deep Blue algorithm, air mass trajectories derived with HYSPLIT model and analysis of meteorological data enabled identification of dust source regions with high temporal (hours) and spatial (ca. 100 km) resolution. Dust, deposited on 5 May 2009, originated in the foothills of the Djebel Akhdar in eastern Libya where dust sources were activated by the intrusion of cold air from the Mediterranean Sea and Saharan low pressure system and transported to the Caucasus along the eastern Mediterranean coast, Syria and Turkey. Particles with an average diameter below 8 μm accounted for 90% of the measured particles in the sample with a mean of 3.58 μm, median 2.48 μm and the dominant mode of 0.60 μm. The chemical signature of this long-travelled dust was significantly different from the locally-produced dust and close to that of soils collected in a palaeolake in the source region, in concentrations of hematite and oxides of aluminium, manganese, and magnesium. Potential addition of dust from a secondary source in northern Mesopotamia introduced uncertainty in the provenancing of dust from this event. Nevertheless, the approach adopted here enables other dust horizons in the snowpack to be linked to specific dust transport events recorded in remote sensing and meteorological data archives.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Rising sea level is perhaps the most severe consequence of climate warming, as much of the world’s population and infrastructure is located near current sea level (Lemke et al. 2007). A major rise of a metre or more would cause serious problems. Such possibilities have been suggested by Hansen and Sato (2011) who pointed out that sea level was several metres higher than now during the Holsteinian and Eemian interglacials (about 250,000 and 120,000 years ago, respectively), even though the global temperature was then only slightly higher than it is nowadays. It is consequently of the utmost importance to determine whether such a sea level rise could occur and, if so, how fast it might happen. Sea level undergoes considerable changes due to natural processes such as the wind, ocean currents and tidal motions. On longer time scales, the sea level is influenced by steric effects (sea water expansion caused by temperature and salinity changes of the ocean) and by eustatic effects caused by changes in ocean mass. Changes in the Earth’s cryosphere, such as the retreat or expansion of glaciers and land ice areas, have been the dominant cause of sea level change during the Earth’s recent history. During the glacial cycles of the last million years, the sea level varied by a large amount, of the order of 100 m. If the Earth’s cryosphere were to disappear completely, the sea level would rise by some 65 m. The scientific papers in the present volume address the different aspects of the Earth’s cryosphere and how the different changes in the cryosphere affect sea level change. It represents the outcome of the first workshop held within the new ISSI Earth Science Programme. The workshop took place from 22 to 26 March, 2010, in Bern, Switzerland, with the objective of providing an in-depth insight into the future of mountain glaciers and the large land ice areas of Antarctica and Greenland, which are exposed to natural and anthropogenic climate influences, and their effects on sea level change. The participants of the workshop are experts in different fields including meteorology, climatology, oceanography, glaciology and geodesy; they use advanced space-based observational studies and state-of-the-art numerical modelling.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The chapter conducts close analysis of the film Midnight (O primeiro dia) in the light of Brazilian history and Brazilian film history

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Fossil pollen, ancient lake sediments and archaeological evidence from Africa indicate that the Sahel and Sahara regions were considerably wetter than today during the early to middle Holocene period, about 12,000 to 5,000 years ago1–4. Vegetation associated with the modern Sahara/Sahel boundary was about 5° farther north, and there were more and larger lakes between 15 and 30° N. Simulations with climate models have shown that these wetter conditions were probably caused by changes in Earth's orbital parameters that increased the amplitude of the seasonal cycle of solar radiation in the Northern Hemisphere, enhanced the land-ocean temperature contrast, and thereby strengthened the African summer monsoon5–7. However, these simulations underestimated the consequent monsoon enhancement as inferred from palaeorecords4. Here we use a climate model to show that changes in vegetation and soil may have increased the climate response to orbital forcing. We find that replacing today's orbital forcing with that of the mid-Holocene increases summer precipitation by 12% between 15 and 22° N. Replacing desert with grassland, and desert soil with more loamy soil, further enhances the summer precipitation (by 6 and 10% respectively), giving a total precipitation increase of 28%. When the simulated climate changes are applied to a biome model, vegetation becomes established north of the current Sahara/Sahel boundary, thereby shrinking the area of the Sahara by 11% owing to orbital forcing alone, and by 20% owing to the combined influence of orbital forcing and the prescribed vegetation and soil changes. The inclusion of the vegetation and soil feedbacks thus brings the model simulations and palaeovegetation observations into closer agreement.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This paper evaluates the impact of the crusades on the landscape and environment of northern Latvia between the 13th–16th centuries (medieval Livonia). The crusades replaced tribal societies in the eastern Baltic with a religious state (Ordenstaat) run by the military orders and their allies, accompanied by significant social, cultural and economic developments. These changes have previously received little consideration in palaeoenvironmental studies of past land use in the eastern Baltic region, but are fundamental to understanding the development and expansion of a European Christian identity. Sediment cores from Lake Trikāta, located adjacent to a medieval castle and settlement, were studied using pollen, macrofossils, loss-on-ignition and magnetic susceptibility. Our results show that despite continuous agricultural land use from 500 BC, the local landscape was still densely wooded until the start of the crusades in AD 1198 when a diversified pattern of pasture, meadow and arable land use was established. Colonisation followed the crusades, although in Livonia this occurred on a much smaller scale than in the rest of the Ordenstaat; Trikāta is atypical showing significant impact following the crusades with many other palaeoenvironmental studies only revealing more limited impact from the 14th century and later. Subsequent wars and changes in political control in the post-medieval period had little apparent effect on agricultural land use.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Let H ∈ C 2(ℝ N×n ), H ≥ 0. The PDE system arises as the Euler-Lagrange PDE of vectorial variational problems for the functional E ∞(u, Ω) = ‖H(Du)‖ L ∞(Ω) defined on maps u: Ω ⊆ ℝ n → ℝ N . (1) first appeared in the author's recent work. The scalar case though has a long history initiated by Aronsson. Herein we study the solutions of (1) with emphasis on the case of n = 2 ≤ N with H the Euclidean norm on ℝ N×n , which we call the “∞-Laplacian”. By establishing a rigidity theorem for rank-one maps of independent interest, we analyse a phenomenon of separation of the solutions to phases with qualitatively different behaviour. As a corollary, we extend to N ≥ 2 the Aronsson-Evans-Yu theorem regarding non existence of zeros of |Du| and prove a maximum principle. We further characterise all H for which (1) is elliptic and also study the initial value problem for the ODE system arising for n = 1 but with H(·, u, u′) depending on all the arguments.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

In the early 1970s, Panama’s negotiations with the United States over the status of the Panama Canal ground to a standstill. General Omar Torrijos had rejected treaties left unratified by previous governments only to receive a less generous offer from the Nixon administration. Realizing that the talks were being ignored in Washington, the Panamanian government worked to internationalize the previously bilateral issue, creating and exploiting a high-profile forum: Extraordinary meetings of the UN Security Council in March 1973 held in Panama City. In those meetings, Panama isolated the United States in order to raise the issue’s profile and amplify the costs of leaving the matter unsettled. Using underutilized Panamanian sources, this article examines that meeting, the succeeding progress, and the effect of this early stage on the final negotiations several years later. The case also illustrates how, during the unsettled international environment of the 1970s, a small state utilized international organizations to obtain attention and support for its most important cause.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Launched with considerable fanfare in 1969, the Committee on the Challenges of Modern Society (CCMS) was supposed to bring new life to NATO by both re-energising public support and engaging with a variety of themes, issues and partners well beyond the alliance’s traditional scope. The first aim of this article is to go beyond the careful media operation that surrounded the launch of the CCMS and to examine the scepticism and resistance of some European partners, particularly the British. The second aim is to demonstrate that NATO started to think in terms of crisis management, disaster relief and environmental disasters well before 1989. The sheer military strength of the alliance and of its partners did remain central – and notably came back to the forefront in 1979 – but the alliance did start to see itself as a geopolitical player and to consider engagement beyond its strictly defined geographical area as early as 1969.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

We describe the advertisement call, tadpole, karyotype, and additional information on the natural history of Cycloramphus lutzorum from southern Brazil. Sonograms were generated from digitally recorded calls. Tadpoles were collected in the field for description in the lab, and an adult was collected for karyotyping. Data on seasonal activity were gathered monthly from November 2005 to November 2007. All tadpoles (N = 21), juveniles (N = 18), and adults (N = 52) were found exclusively in streams. Reproduction, as identified by calling frogs, occurred from July through November. Frogs call all day long, but mostly at dusk, from rock crevices inside the stream edges near the splash zone. The call is short and loud, with 11 pulsed notes, of 491-641 ms, with a dominant frequency of 0.98-1.39 kHz. We describe the exotrophic and semiterrestrial tadpoles, always found in constantly humid vertical rock walls in the stream. Tadpoles of C. lutzorum are recognized by differences in labial tooth row formula, eye diameter, body shape, position of nares, and development of tail. Like congeneric species, the karyotype of C. lutzorum comprises 26 metacentric and submetacentric chromosomes. Cycloramphus lutzorum is restricted to and adapted for living in fast flowing streams, many of which are threatened by deforestation, pollution, and habitat loss. Therefore, we recommend the status of C. lutzorum be changed from its current ""Data Deficient"" to ""Near Threatened (NT)"" in the IUCN species red list.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This article is an analysis of the story of the killing of Ḥusayn b. ʿAlī at Karbalāʾ in 61/680, as it is presented by Abū Jaʿfar Muḥammad b. Jarīr al-Ṭabarī (d. 310/923). The main argument is that the notion of the divine covenant, which permeates the Qur’an, constitutes a framework through which al-Ṭabarī views this event. The Qur’anic idea of the covenant is read in structural/thematic continuity with the Hebrew Bible account of the covenant between Yahweh and the Hebrew people, which has, in turn, been traced back in its basic form to Late Bronze Era treaties between rulers and their vassals.   The present study focusses on four speeches ascribed to Ḥusayn during the encounter he and his group had with the vanguard of the Kūfan army led by al-Ḥurr. These are analysed in accordance with their use of Qur’anic covenant vocabulary. They are also categorised within the broader framework of the eight standard characteristics of Ancient West Asian and Biblical covenants, as presented by George Mendenhall and Gary Herion, which have recently been developed in a Qur’anic context by Rosalind Ward Gwynne. This article argues that al-Ṭabarī’s Karbalāʾ narrative presents the pact of loyalty to Ḥusayn as a clear extension of the divine covenant.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Samurai in the Surf explores the history of Japanese investment in the 1980s, following a money-trail that leads back to a ballooning Japanese economy and a colorful array of investment sources. The book also explores the local community's views of this unprecedented stream of foreign investment and provides a convincing illustration of the links between 1980s Queensland and Pauline Hanson's One Nation movement of the 1990s.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This paper gives an up-to-date overview on the Australian cashmere industry.  It covers the development history of Australian cashmere industry, the characteristics of Australian cashmere fibres, cashmere processing and research and development in Australia.