966 research outputs found

    Aboriginal Forestry: Community Management as Opportunity and Imperative

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    In recognition that forests are one of their greatest resources, Aboriginal peoples are considering how altered tenure arrangements might uphold traditional values, including ecological integrity, while providing economic and employment opportunities. However, the federal and provincial forest management structures have historically precluded First Nations from helping to define, and participate in, the forest industry. The authors explore the legal and regulatory basis of forest management in Canada, and assess how it facilitates or impedes Aboriginal management of traditional areas. This is done through a legislative and policy analysis, and through the use of case studies from across Canada. The authors propose an approach to tenure reform that will allow First Nations to achieve ecosystem-based community forestry through the use of traditional governance structures

    Partial synchronisation of stochastic oscillators through hydrodynamic coupling

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    Holographic optical tweezers are used to construct a static bistable optical potential energy landscape where a Brownian particle experiences restoring forces from two nearby optical traps and undergoes thermally activated transitions between the two energy minima. Hydrodynamic coupling between two such systems results in their partial synchronisation. This is interpreted as an emergence of higher mobility pathways, along which it is easier to overcome barriers to structural rearrangement.Comment: 4 pages, 4 figures, submitted to Phys. Rev. Let

    Postrelease survival, vertical and horizontal movements, and thermal habitats of five species of pelagic sharks in the central Pacific Ocean

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    From 2001 to 2006, 71 pop-up satellite archival tags (PSATs) were deployed on five species of pelagic shark (blue shark [Prionace glauca]; shortfin mako [Isurus oxyrinchus]; silky shark [Carcharhinus falciformis]; oceanic whitetip shark [C. longimanus]; and bigeye thresher [Alopias superciliosus]) in the central Pacific Ocean to determine species-specific movement patterns and survival rates after release from longline fishing gear. Only a single postrelease mortality could be unequivocally documented: a male blue shark which succumbed seven days after release. Meta-analysis of published reports and the current study (n=78 reporting PSATs) indicated that the summary effect of postrelease mortality for blue sharks was 15% (95% CI, 8.5–25.1%) and suggested that catch-and-release in longline fisheries can be a viable management tool to protect parental biomass in shark populations. Pelagic sharks displayed species-specific depth and temperature ranges, although with significant individual temporal and spatial variability in vertical movement patterns, which were also punctuated by stochastic events (e.g., El Niño-Southern Oscillation). Pelagic species can be separated into three broad groups based on daytime temperature preferences by using the unweighted pair-group method with arithmetic averaging clustering on a Kolmogorov-Smirnov Dmax distance matrix: 1) epipelagic species (silky and oceanic whitetip sharks), which spent >95% of their time at temperatures within 2°C of sea surface temperature; 2) mesopelagic-I species (blue sharks and shortfin makos, which spent 95% of their time at temperatures from 9.7° to 26.9°C and from 9.4° to 25.0°C, respectively; and 3) mesopelagic-II species (bigeye threshers), which spent 95% of their time at temperatures from 6.7° to 21.2°C. Distinct thermal niche partitioning based on body size and latitude was also evident within epipelagic species

    Development of arcjet and ion propulsion for spacecraft stationkeeping

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    Near term flight applications of arc jet and ion thruster satellite station-keeping systems as well as development activities in Europe, Japan, and the United States are reviewed. At least two arc jet and three ion propulsion flights are scheduled during the 1992-1995 period. Ground demonstration technology programs are focusing on the development of kW-class hydrazine and ammonia arc jets and xenon ion thrusters. Recent work at NASA LeRC on electric thruster and system integration technologies relating to satellite station keeping and repositioning will also be summarized

    Electrophysiological correlates of high-level perception during spatial navigation

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    We studied the electrophysiological basis of object recognition by recording scalp\ud electroencephalograms while participants played a virtual-reality taxi driver game.\ud Participants searched for passengers and stores during virtual navigation in simulated\ud towns. We compared oscillatory brain activity in response to store views that were targets or\ud nontargets (during store search) or neutral (during passenger search). Even though store\ud category was solely defined by task context (rather than by sensory cues), frontal ...\ud \u

    Computer aided manual validation of mass spectrometry-based proteomic data

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    Advances in mass spectrometry-based proteomic technologies have increased the speed of analysis and the depth provided by a single analysis. Computational tools to evaluate the accuracy of peptide identifications from these high-throughput analyses have not kept pace with technological advances; currently the most common quality evaluation methods are based on statistical analysis of the likelihood of false positive identifications in large-scale data sets. While helpful, these calculations do not consider the accuracy of each identification, thus creating a precarious situation for biologists relying on the data to inform experimental design. Manual validation is the gold standard approach to confirm accuracy of database identifications, but is extremely time-intensive. To palliate the increasing time required to manually validate large proteomic datasets, we provide computer aided manual validation software (CAMV) to expedite the process. Relevant spectra are collected, catalogued, and pre-labeled, allowing users to efficiently judge the quality of each identification and summarize applicable quantitative information. CAMV significantly reduces the burden associated with manual validation and will hopefully encourage broader adoption of manual validation in mass spectrometry-based proteomics.National Institutes of Health (U.S.) (Grant R24DK090963)National Institutes of Health (U.S.) (Grant U54CA112967)National Cancer Institute (U.S.). Integrative Cancer Biology Program (Fellowship)Charles S. Krakauer FellowshipHugh Hampton Young Fellowshi

    A response to “Likelihood ratio as weight of evidence: a closer look” by Lund and Iyer

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    Recently, Lund and Iyer (L&I) raised an argument regarding the use of likelihood ratios in court. In our view, their argument is based on a lack of understanding of the paradigm. L&I argue that the decision maker should not accept the expert’s likelihood ratio without further consideration. This is agreed by all parties. In normal practice, there is often considerable and proper exploration in court of the basis for any probabilistic statement. We conclude that L&I argue against a practice that does not exist and which no one advocates. Further we conclude that the most informative summary of evidential weight is the likelihood ratio. We state that this is the summary that should be presented to a court in every scientific assessment of evidential weight with supporting information about how it was constructed and on what it was based

    Media Systems and the Political Information Environment: A Cross-National Comparison

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    To express attitudes and act according to their self-interest, citizens need relevant, up-to-date information about current affairs. But has the increased commercialization in the media market increased or decreased the flow of political information? Hallin and Mancini stress that the existing empirical evidence is fragmented and that this question therefore has been difficult to answer. In this article the authors present new data that allow them to systematically examine how the flow of political information on TV occurs across six Western countries during a thirty-year period. The authors find that the flow of political information through TV varies according to the degree of commercialization. The flow of news and current affairs is lowest in the most commercially oriented television system and among the commercial TV channels. There is however important cross-national variation even within similar media systems. The authors’ data do not suggest a convergence toward the liberal system when it comes to the political information environment on TV. Rather, what strikes them is how strongly resistant some European countries have been to subordinating the needs of democracy to profit making

    Molecular Characterization of Two Opecoelid Trematodes From Fishes in the Gulf of Mexico, With a Desceiption of a New Species of \u3ci\u3eHelicometra\u3c/i\u3e

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    The plagioporine opecoelids Helicometra fasciata (Rudolphi, 1819) Odhner, 1902, and Macvicaria crassigula (Linton, 1910) Bartoli, Bray, and Gibson, 1989 have been reported from fishes in expansive geographic regions, disjointed from their type localities. New material of M. crassigula was collected from near its type locality as well as specimens resembling Helicometra fasciata sensu lato from three triglids in the Gulf of Mexico. Comparisons of the ribosomal DNA (rDNA) sequences, comprising the partial 18S rDNA, internal transcribed spacer region (= ITS1, 5.8S, and ITS2), and partial 28S rDNA gene, from M. crassigula and Helicometra fasciata sensu lato in the Gulf of Mexico were made with sequences deposited in GenBank from those species from the Mediterranean Sea. Results reveal that M. crassigula sensu stricto from the Gulf of Mexico is distinct from the two cryptic species of M. crassigula sensu lato from the Mediterranean Sea and Helicometra fasciata sensu lato in this study differs from H. fasciata sequences from the Mediterranean Sea, thus Helicometra manteri sp. nov. is described
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