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1.
Stimulated Raman scattering is used to prepare ensembles of aligned acetylene molecules in thev 2=1 excited vibrational level. Decay and transfer of the alignment is followed by laser induced fluorescence. Measurements of the initially excited alignment agree well with theoretical calculations. The rate constants for decay decrease as the rotational quantum numberJ of the excited level increases.  相似文献   
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The Mirdita Ophiolite Zone in Albania is associated with widespread mélanges containing components of up to nappe-size. We dated matrix and components of the mélange by radiolarians, conodonts, and other taxa. The components consist of radiolarites, pelagic limestones and shallow-water limestones, all of Triassic age, as well as ophiolites. Triassic radiolarite as a primary cover of ophiolite material proves Middle Triassic onset of Mirdita ocean-floor formation. The mélange contains a turbiditic radiolarite-rich matrix (“radiolaritic flysch”), dated as Late Bajocian to Early Oxfordian. It formed as a synorogenic sediment during west-directed thrusting of ophiolite and sediment-cover nappes representing ocean floor and underplated fragments of the western continental margin. The tectonic structures formed during these orogenic events (“Younger Kimmeridian or Eohellenic Orogeny”) are sealed by Late Jurassic platform carbonates. The geological history conforms with that of the Inner Dinarides and adjoining areas; we therefore correlate the Mirdita-Pindos Ophiolite Zone with the Vardar Zone and explain its present position by far-distance west-directed thrusting.  相似文献   
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The declining health of marine ecosystems around the world is evidence that current piecemeal governance is inadequate to successfully support healthy coastal and ocean ecosystems and sustain human uses of the ocean. One proposed solution to this problem is ecosystem-based marine spatial planning (MSP), which is a process that informs the spatial distribution of activities in the ocean so that existing and emerging uses can be maintained, use conflicts reduced, and ecosystem health and services protected and sustained for future generations. Because a key goal of ecosystem-based MSP is to maintain the delivery of ecosystem services that humans want and need, it must be based on ecological principles that articulate the scientifically recognized attributes of healthy, functioning ecosystems. These principles should be incorporated into a decision-making framework with clearly defined targets for these ecological attributes. This paper identifies ecological principles for MSP based on a synthesis of previously suggested and/or operationalized principles, along with recommendations generated by a group of twenty ecologists and marine scientists with diverse backgrounds and perspectives on MSP. The proposed four main ecological principles to guide MSP—maintaining or restoring: native species diversity, habitat diversity and heterogeneity, key species, and connectivity—and two additional guidelines, the need to account for context and uncertainty, must be explicitly taken into account in the planning process. When applied in concert with social, economic, and governance principles, these ecological principles can inform the designation and siting of ocean uses and the management of activities in the ocean to maintain or restore healthy ecosystems, allow delivery of marine ecosystem services, and ensure sustainable economic and social benefits.  相似文献   
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Plutons of quartz diorite to adamellite composition give Rb-Sr total-rock and biotite calculated ages of 12 to 176 m.y. along a transect of the Chilean Andes between 45° and 46° S. Miocene biotite dates of quartz diorite from the Puerto Aisen area are interpreted as minimum ages related to probable local structural deformation (faulting). Along a north-south traverse of the Argentine Andes between 40° and 44° S, plutons of similar composition to the Chilean Andes give KAr and RbSr total-rock and mineral dates which range from late Paleozoic to Cretaceous. No systematic unidirectional migration of the radiometric ages is observed.  相似文献   
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Zusammenfassung Die Entwicklung der Technik führt zu immer größeren Bauprojekten im Bereich des Talsperrenbaus, Verkehrswegebaus, Untertagebaus, Bergbaus und Grundbaus. Diese großen Bauprojekte stellen in vielfacher Hinsicht eine erhebliche Belastung der Natur sowie eine Beeinträchtigung ihres Gleichgewichts dar und rufen teilweise unvorhergesehene Wechselwirkungen von Bauwerk und Baugrund hervor. Die technische Entwicklung überrollte die Natur so stürmisch, daß ihre ökologischen Folgen weder von den Wissenschaftlern noch von den Praktikern erkannt und bedacht wurden. Die Aufgaben, die sich in diesem Rahmen dem Ingenieurgeologen stellen, bestehen nicht nur in der möglichst genauen Erfassung der geologischen Parameter zur Gewährleistung der Sicherheit des Bauwerks, wirtschaftlich vertretbarer Baukosten unter optimaler Berücksichtigung geologischer Gegebenheiten, sondern sie haben auch die Vorhersage der Wechselwirkungen von Bauwerk und Baugrund sowie von Störungen des oft erstaunlich labilen Gleichgewichts von Geo-, Bio- und Atmosphäre einzubeziehen. Dabei spielen oft rezente geologische Vorgänge eine bisher in der Ingenieurgeologie viel zu wenig gewürdigte Rolle. Die Notwendigkeit, die Ingenieurgeologie schon bei der allerersten Planung, beim Entwurf und der Bauwerksüberwachung mitbestimmen zu lassen, wird an einzelnen Projekten erläutert.
Summary Technical development leads to dams, roads, tunnels, mines and foundations of always larger dimensions. Various aspects of these projects represent a serious encumbrance of nature and an impairment of her equilibrium and can cause unforeseen interactions between structure and the earth. Development has taken place so quickly, that the ecological consequences have not been recognised or considered in many cases — neither by the scientists nor by the practitioners. The tasks, confronting the engineering geologists in this regard, consist not only in an exact investigation of the geological parameters to guarantee the safety of the construction project and to achieve project costs by taking into consideration the geological conditions, but must encompass the recognition of the interactions of construction and the earth as well as the disturbance of the often astonishingly fragile equilibrium of the geo-, bio- and atmosphere. Specifically recent geological processes are often not accounted for, despite their possibly disadvantageous effects. The necessity, that the engineering geologist contributes in all project stages from the first planning, to the design upto the surveillance of the construction, is stressed by giving examples.

Résumé Le développement technique a conduit à des projets de construction toujour plus grands dans le domain des barrages, des routes, des tunnels, des mines et des fondations. Ces grands projets représentent sous beaucoup d'aspects une immense contreinte pour l'environnement naturel, un préjudice pour son équilibre et conduisent parfois à une interaction imprévue entre la construction et le sol. Le développement fut si rapide que les conséquences écologiques ne furent pas reconnues et prises en compte, ni par la science ni par la pratique. Les taches, qui se présentent au géologue ingénieur sur le terrain, comprennent non seulement l'investigation exacte des paramètres géologiques dans le but d'assurer la securité de la construction pour des frais raisonnables tout en prenant en compte d'une façon optimale les conditions géologiques, mais aussi la prévision de ces interactions entre l'ouvrage et le sol, ainsi que les perturbations de l'équilibre de l'environnement géologique, biologique et atmosphérique, équilibre qui est souvent éxtrêmement fragile.Les phénomènes géologiques récents ne sont que très peu considérés dans ces études. La necessité de la participation du géologue ingénieur dès le début des études pendant la conception et la surveillance de l'ouvrage est illustrée à l'aide de projets particuliers.

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8.
Abstract

During November 1976 to February 1977 near‐surface wind, current and temperature measurements were made at three sites along the Strait of Juan de Fuca. Strong tidal currents and major intrusions of warmer, fresher offshore coastal water were superimposed upon the estuarine circulation of near‐surface seaward flow. The r.m.s. amplitudes of the diurnal and semidiurnal tidal currents were ~30 cms‐1 and 30–47 cm s‐1, respectively. The vector‐mean flow at 4 m‐depth was seaward and decreased in speed from 28 cm s‐1 at 74 km from the entrance to 9 cm s‐1 at 11 km from the entrance. On five occasions intrusions of 1–3 C warmer northeast Pacific coastal water occurred for durations of 1–10 days. The 25 cm s‐1 up‐strait speed of the intrusive lens agreed to within 20% of the gravity current speed computed from Benjamin's (1968) hydraulic model. The near‐surface currents associated with the intrusions and the southerly coastal winds were significantly correlated, indicating that the intrusions were initiated when shoreward Ekman currents advected Pacific coastal water into the Strait. The reversals were not significantly coherent with the along‐strait sea surface slope measured along the north side of the Strait nor were they strongly related to local wind forcing.  相似文献   
9.
Globalization,Pacific Islands,and the paradox of resilience   总被引:1,自引:0,他引:1  
On April 2nd, 2007 a 12 m tsunami struck Simbo, a relatively remote island in Western Province, Solomon Islands. Although Simbo's population continues to depend on their own food production and small-scale governance regimes regulate access to resources, the island's way of life over the last century has increasingly been affected by processes associated with globalization. In this context of a rapidly globalizing world, this article examines the island's resilience and vulnerability to the tsunami and the adaptive capacities that enabled the response and recovery. The tsunami completely destroyed two villages and damaged fringing coral reefs, but casualties were low and social–ecological rebound relatively brisk. By combining social science methods (household surveys, focus group and ethnographic interviews) and underwater reef surveys we identify a number of countervailing challenges and opportunities presented by globalization that both nurture and suppress the island's resilience to high amplitude, low-frequency disturbances like tsunamis. Analysis suggests that certain adaptive capacities that sustain general system resilience come at the cost of more vulnerability to low-probability hazards. We discuss how communities undergoing increasingly complex processes of change must negotiate these kinds of trade-offs as they manage resilience at multiple spatial and temporal scales. Understanding the shifting dynamics of resilience may be critical for Pacific Island communities who seek to leverage globalization in their favor as they adapt to current social–ecological change and prepare for future large-scale ecological disturbances.  相似文献   
10.
Blocks and tectonic slices within the Mersin Mélange (southern Turkey), which are of Northern Neotethyan origin (Izmir–Ankara–Erzincan Ocean (IAE)), were studied in detail by using radiolarian, conodont, and foraminiferal assemblages on six different stratigraphic sections with well‐preserved Permian succesions. The basal part of the Permian sequence, composed of alternating chert and mudstone with basic volcanics, is assigned to the late Asselian (Early Permian) based on radiolarians. The next basaltic interval in the sequence is dated as Kungurian. The highly alkaline basic volcanics in the sequence are extremely enriched, similar to kimberlitic/lamprophyric magmas generated at continental intraplate settings. Trace element systematics suggest that these lavas were generated in a continental margin involving a metasomatized subcontinental lithospheric mantle source (SCLM). The middle part of the Permian sequences, dated by benthic foraminifera and conodont assemblages, includes detrital limestones with chert interlayers and neptunian dykes of middle Wordian to earliest Wuchiapingian age. Higher in the sequence, detrital limestones are overlain by alternating chert and mudstone with intermittent microbrecciated beds of early Wuchiapingian to middle Changhsingian (Late Permian) age based on the radiolarians. A large negative shift at the base of the Lopingian at the upper part of section is correlated to negative shifts at the Guadalupian/Lopingian boundary associated with the end‐Guadalupian mass extinction event. All these findings indicate that a continental rift system associated with a possible mantle plume existed during the late Early to Late Permian period. This event was responsible for the rupturing of the northern Gondwanan margin related to the opening of the IAE Ocean. When the deep basinal features of the Early Permian volcano‐sedimentary sequence are considered, the proto IAE oceanic crust formed possibly before the end of the Permian. This, in turn, suggests that the opening of the IAE Ocean dates back to as early as the Permian.  相似文献   
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