1,186 research outputs found

    Deep-water turbidites as Holocene earthquake proxies: the Cascadia subduction zone and Northern San Andreas Fault systems

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    New stratigraphic evidence from the Cascadia margin demonstrates that 13 earthquakes ruptured the margin from Vancouver Island to at least the California border following the catastrophic eruption of Mount Mazama. These 13 events have occurred with an average repeat time of ?? 600 years since the first post-Mazama event ?? 7500 years ago. The youngest event ?? 300 years ago probably coincides with widespread evidence of coastal subsidence and tsunami inundation in buried marshes along the Cascadia coast. We can extend the Holocene record to at least 9850 years, during which 18 events correlate along the same region. The pattern of repeat times is consistent with the pattern observed at most (but not all) localities onshore, strengthening the contention that both were produced by plate-wide earthquakes. We also observe that the sequence of Holocene events in Cascadia may contain a repeating pattern, a tantalizing look at what may be the long-term behavior of a major fault system. Over the last ?? 7500 years, the pattern appears to have repeated at least three times, with the most recent A.D. 1700 event being the third of three events following a long interval of 845 years between events T4 and T5. This long interval is one that is also recognized in many of the coastal records, and may serve as an anchor point between the offshore and onshore records. Similar stratigraphic records are found in two piston cores and one box core from Noyo Channel, adjacent to the Northern San Andreas Fault, which show a cyclic record of turbidite beds, with thirty- one turbidite beds above a Holocene/.Pleistocene faunal «datum». Thus far, we have determined ages for 20 events including the uppermost 5 events from these cores. The uppermost event returns a «modern» age, which we interpret is likely the 1906 San Andreas earthquake. The penultimate event returns an intercept age of A.D. 1664 (2 ?? range 1505- 1822). The third event and fourth event are lumped together, as there is no hemipelagic sediment between them. The age of this event is A.D. 1524 (1445-1664), though we are not certain whether this event represents one event or two. The fifth event age is A.D. 1204 (1057-1319), and the sixth event age is A.D. 1049 (981-1188). These results are in relatively good agreement with the onshore work to date, which indicates an age for the penultimate event in the mid-1600 s, the most likely age for the third event of ?? 1500-1600, and a fourth event ?? 1300. We presently do not have the spatial sampling needed to test for synchroneity of events along the Northern San Andreas, and thus cannot determine with confidence that the observed turbidite record is earthquake generated. However, the good agreement in number of events between the onshore and offshore records suggests that, as in Cascadia, turbidite triggers other than earthquakes appear not to have added significantly to the turbidite record along the northernmost San Andreas margin during the last ?? 2000 years

    A Critical Assessment of Protection for Key Wildlife and Salmon Habitats under the Proposed British Columbia Central Coast Land and Resource Management Plan

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    The Central Coast Land and Resource Management Plan (CCLRMP) table recently declared a consensus1 on proposed protected areas for British Columbia’s Central Coast. This region is recognized for its globally rare and largely intact mainland and island ecosystems and land use decisions should reflect this importance. We evaluated the efficacy of this proposal using a spatial assessment of habitat. We focus on protected areas in the context of the overall CCLRMP. We examined the level of protection provided by the CCLRMP in three key coastal habitats: deer winter range, wolf reproductive habitat, and salmon reproductive and rearing habitat. Assessment of deer winter range was limited to Heiltsuk Territory, which comprises a large proportion of the CCLRMP region

    Development of a Grazing Land Management Education Program for Northern Australia’s Grasslands and Grassy Woodlands

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    Recognition of the potential to enhance grazing land management to meet the goal of sustainable beef production has been increasing over the past decade. Recognition of the relationship between poor land management and negative off-site environmental impacts, such as soil erosion and a decline in the condition of rivers and adjacent near shore coastal areas from sediment transport, has increased also. This concern has matured somewhat to include the critical link between land condition and production, and the threat to sustainable carrying capacity that comes from declining land condition. Concurrently, interest has increased in optimising the use of pasture, e.g. through the development of infrastructure (watering points, fencing), through more pro-active management e.g. alternative grazing systems, spelling of pastures, and through pasture development. In fact, it can be argued that achieving production goals while improving and maintaining the health of the land has become the major on-property issue for northern Australian graziers

    The Elephant (Head) in the Room: A Critical Look at Trophy Hunting

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    Trophy hunting has occupied a prominent position in recent scholarly literature and popular media. In the scientific conservation literature, researchers are generally supportive of or sympathetic to its usage as a source of monetary support for conservation. Although authors at times acknowledge that trophy hunting faces strong opposition from many members of the public, often for unspecified reasons associated with ethics, neither the nature nor the implications of these ethical concerns have been substantively addressed. We identify the central act of wildlife “trophy” taking as a potential source of ethical discomfort and public opposition. We highlight that trophy hunting entails a hunter paying a fee to kill an animal and claim its body or body parts as a trophy of conquest. Situating this practice in a Western cultural narrative of chauvinism, colonialism, and anthropocentrism, we argue trophy hunting is morally inappropriate. We suggest alternative strategies for conservation and community development should be explored and decisively ruled out as viable sources of support before the conservation community endorses trophy hunting. If wildlife conservation is broadly and inescapably dependent on the institution of trophy hunting, conservationists should accept the practice only with a due appreciation of tragedy, and proper remorse

    Establishment and persistence of legumes on sites varying in aspect, landscape position and soil type

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    Most Iowa pastures display only a small variety of plant species, resulting in large seasonal and annual variations in pasture productivity. This project evaluated the causes for these variations in cool-season grass pastures and considered ways to improve diversity of legume species used for grazing

    Multilab Direct Replication of Flavell, Beach, and Chinsky (1966): Spontaneous Verbal Rehearsal in a Memory Task as a Function of Age

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    Work by Flavell, Beach, and Chinsky indicated a change in the spontaneous production of overt verbalization behaviors when comparing young children (age 5) with older children (age 10). Despite the critical role that this evidence of a change in verbalization behaviors plays in modern theories of cognitive development and working memory, there has been only one other published near replication of this work. In this Registered Replication Report, we relied on researchers from 17 labs who contributed their results to a larger and more comprehensive sample of children. We assessed memory performance and the presence or absence of verbalization behaviors of young children at different ages and determined that the original pattern of findings was largely upheld: Older children were more likely to verbalize, and their memory spans improved. We confirmed that 5- and 6-year-old children who verbalized recalled more than children who did not verbalize. However, unlike Flavell et al., substantial proportions of our 5- and 6-year-old samples overtly verbalized at least sometimes during the picture memory task. In addition, continuous increase in overt verbalization from 7 to 10 years old was not consistently evident in our samples. These robust findings should be weighed when considering theories of cognitive development, particularly theories concerning when verbal rehearsal emerges and relations between speech and memory

    Progress in Validation of Wind-US for Ramjet/Scramjet Combustion

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    Validation of the Wind-US flow solver against two sets of experimental data involving high-speed combustion is attempted. First, the well-known Burrows- Kurkov supersonic hydrogen-air combustion test case is simulated, and the sensitively of ignition location and combustion performance to key parameters is explored. Second, a numerical model is developed for simulation of an X-43B candidate, full-scale, JP-7-fueled, internal flowpath operating in ramjet mode. Numerical results using an ethylene-air chemical kinetics model are directly compared against previously existing pressure-distribution data along the entire flowpath, obtained in direct-connect testing conducted at NASA Langley Research Center. Comparison to derived quantities such as burn efficiency and thermal throat location are also made. Reasonable to excellent agreement with experimental data is demonstrated for key parameters in both simulation efforts. Additional Wind-US feature needed to improve simulation efforts are described herein, including maintaining stagnation conditions at inflow boundaries for multi-species flow. An open issue regarding the sensitivity of isolator unstart to key model parameters is briefly discussed
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