231 research outputs found

    Exploring intraspecific life history patterns in sharks

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    Marine ecosystems compose the major source (85%) of world fisheries production (Garcia and Newton, 1997). Although only a few fish species tend to dominate fishery catches (Jennings et al., 2001), a large diversity of fishes representing varied taxonomic levels, ecological guilds, and life histories is commonly taken. Recently, 66% of global marine resources were determined to be either fully, heavily, or over-exploited (Botsford et al., 1997). Considering the current state of many fisheries, the large diversity of species taken globally, and the general lack of resources to adequately assess many stocks, it has become important to develop shortcuts that may provide methods fisheries scientists can use to determine which stocks are in danger of overexploitation and which recovery plans are appropriate when biological data are limited (Stobutzki et al., 2001)

    I think therefore I learn? Entrepreneurial cognition, learning and knowing in practice

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    In observing recent theoretical developments in the field, it is apparent that two distinctive yet relatively separate areas of study have emerged—entrepreneurial cognition and entrepreneurial learning. This conceptual paper aims to create some measure of reconciliation between these two perspectives to provide a more robust and multidisciplinary conceptual platform for understanding the entrepreneur. We augment an appreciation of the social dimensions of the learning process by which entrepreneurs cognitively acquire and transform knowledge. Through the application of influential practice-based theorizing we offer an integrative organizing framework that places participation at the heart of entrepreneurial practice, knowledge and identity

    Entrepreneurial learning from failure : an interpretative phenomenological analysis

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    This paper develops a deeper conceptualisation of venture failure from a learning perspective. Moving beyond the causes of failure, I seek to develop a richer picture of the impact and outcomes of failure and the learning processes by which entrepreneurs actively grieve for, and recover from, the loss of a business. Based on interpretative phenomenological research with eight entrepreneurs, this paper adds valuable empirical weight to extant conceptual discussions of failure. Marrying emergent literature on entrepreneurial learning with theories of failure, I propose distinctive higher-level learning processes triggered by failure that prove fundamental in personal and business terms. These learning outcomes provide entrepreneurs with invaluable insights into the 'pressure points' of the entrepreneurial process, significantly augmenting levels of entrepreneurial preparedness for future enterprising activity

    Using productivity and susceptibility indices to assess the vulnerability of United States fish stocks to overfishing

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    Assessing the vulnerability of stocks to fishing practices in U.S. federal waters was recently highlighted by the National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration, as an important factor to consider when 1) identifying stocks that should be managed and protected under a fishery management plan; 2) grouping data-poor stocks into relevant management complexes; and 3) developing precautionary harvest control rules. To assist the regional fishery management councils in determining vulnerability, NMFS elected to use a modified version of a productivity and susceptibility analysis (PSA) because it can be based on qualitative data, has a history of use in other fisheries, and is recommended by several organizations as a reasonable approach for evaluating risk. A number of productivity and susceptibility attributes for a stock are used in a PSA and from these attributes, index scores and measures of uncertainty are computed and graphically displayed. To demonstrate the utility of the resulting vulnerability evaluation, we evaluated six U.S. fisheries targeting 162 stocks that exhibited varying degrees of productivity and susceptibility, and for which data quality varied. Overall, the PSA was capable of differentiating the vulnerability of stocks along the gradient of susceptibility and productivity indices, although fixed thresholds separating low-, moderate-, and highly vulnerable species were not observed. The PSA can be used as a flexible tool that can incorporate regional-specific information on fishery and management activity

    Co-occurrence of bycatch and target species in the groundfish demersal trawl fishery of the U.S. west coast; with special consideration of rebuilding stocks

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    Bycatch and resultant discard mortality are issues of global concern. The groundfish demersal trawl fishery on the west coast of the United States is a multispecies fishery with significant catch of target and nontarget species. These catches are of particular concern in regard to species that have previously been declared overfished and are currently rebuilding biomass back to target levels. To understand these interactions better, we used data from the West Coast Groundfish Observer Program in a series of cluster analyses to evaluate 3 questions: 1) Are there identifiable associations between species caught in the bottom trawl fishery; 2) Do species that are undergoing population rebuilding toward target biomass levels (“rebuilding species”) cluster with targeted species in a consistent way; 3) Are the relationships between rebuilding bycatch species and target species more resolved at particular spatial scales or are relationships spatially consistent across the whole data set? Two strong species clusters emerged—a deepwater slope cluster and a shelf cluster—neither of which included rebuilding species. The likelihood of encountering rebuilding rockfish species is relatively low. To evaluate whether weak clustering of rebuilding rockfish was attributable to their low rate of occurrence, we specified null models of species occurrence. Results indicated that the ability to predict occurrence of rebuilding rockfish when target species were caught was low. Cluster analyses performed at a variety of spatial scales indicated that the most reliable clustering of rebuilding species was at the spatial scale of individual fishing ports. This finding underscores the value of spatially resolved data for fishery management

    Apparatus and method for removal of seed pericarp

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    Presents an apparatus and method for removing pericarp from a seed, such as a corn kernel. The method includes sonicating the kernel to loosen the pericarp and then separation of the pericarp. One example of separation is by frictional milling. An additional optional aspect of the invention is isolation of the pericarp from the remainder of the seed and/or further cleaning or purification of the pericarp

    Chlorido{2-[(dimethyl­amino)­methyl]phenyl-κ2 C 1,N}(1-methyl-1H-imidazole-κN 3)palladium(II)

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    In the title compound, [Pd(C9H12N)Cl(C4H6N2)], which was synthesized from the reaction of 1-methyl­imidazole with dimeric dichloridobis[2-(dimethyl­amino)­benz­yl]palla­dium(II), the ring-deprotonated N,N-dimethyl­benzyl­amine ligand acts in a C,N-bidentate fashion. The dihedral angle between the ring of the 1-methyl­imidazole ligand and the palladacycle plane is 57.88 (16)°. The two N atoms from the N,N-dimethyl­benzyl­amine and 1-methyl­imidazole ligands are trans coordinated to the PdII atom

    Phylogenomic Reconstruction of the Neotropical Poison Frogs (Dendrobatidae) and Their Conservation

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    The evolutionary history of the Dendrobatidae, the charismatic Neotropical poison frog family, remains in flux, even after a half-century of intensive research. Understanding the evolutionary relationships between dendrobatid genera and the larger-order groups within Dendrobatidae is critical for making accurate assessments of all aspects of their biology and evolution. In this study, we provide the first phylogenomic reconstruction of Dendrobatidae with genome-wide nuclear markers known as ultraconserved elements. We performed sequence capture on 61 samples representing 33 species across 13 of the 16 dendrobatid genera, aiming for a broadly representative taxon sample. We compare topologies generated using maximum likelihood and coalescent methods and estimate divergence times using Bayesian methods. We find most of our dendrobatid tree to be consistent with previously published results based on mitochondrial and low-count nuclear data, with notable exceptions regarding the placement of Hyloxalinae and certain genera within Dendrobatinae. We also characterize how the evolutionary history and geographic distributions of the 285 poison frog species impact their conservation status. We hope that our phylogeny will serve as a backbone for future evolutionary studies and that our characterizations of conservation status inform conservation practices while highlighting taxa in need of further study

    ESA-listed Puget Sound rockfish: How did we get here and how do we assess progress towards recovery planning goals?

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    In Puget Sound, WA, rockfish abundance declined significantly over the last 50+ years as a result of fishing pressure, life-history characteristics and the isolated geography of Puget Sound. In 2010, three species of rockfish were listed under the Endangered Species Act (ESA): yelloweye rockfish, canary rockfish and bocaccio. Due to a general lack of data specific to these three species, data from other rockfish species were used to support the listings. Since the listings, targeted research and recovery planning has begun to address major data gaps for these three species. First, cooperative research with the recreational fishing community has revealed that yelloweye rockfish are genetically distinct from coastal populations, whereas canary rockfish are not distinct - which has led to canary rockfish being delisted, the first delisting of a marine fish. Second, an ROV survey has been designed specifically to provide a path forward to estimate changes in abundance of listed rockfish in Puget Sound. Third, the Rockfish Recovery Plan for yelloweye rockfish and bocaccio has been published. This plan provides, and we have begun to address, a list of research activities related to environmental conditions and human activities that might constrain rockfish recovery. Two ongoing studies examine whether specific environmental covariates (e.g. dissolved oxygen) alter the movement and foraging behavior of yelloweye rockfish and whether rockfish bycatch can be reduced in the recreational lingcod fishery by using specific bait types. Finally, we will discuss the criteria to be used for delisting these species under the ESA, including statistical methods and operational challenges
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