1,766 research outputs found

    Using a Modified Purse Seine to Collect and Monitor Estuarine Fishes

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    We developed a modified purse seine to sample shallow water estuarine habitats and evaluated the efficacy of using this gear as a tool for monitoring estuarine fish populations in Tampa Bay, Florida. The purse seine (183-m long, 5.2 m deep and 50-mm stretch mesh nylon throughout) was easily deployed and retrieved by a 7 m flat-bottomed, bow-driven boat with a hydraulic wench and aluminum pursing davit. Retention rates of pinfish (Lagodon rhomboides) marked and released into 35 net sets averaged 49% (range 9-100%). Retention rates were not significantly influenced by sets over vegetated and unvegetated bottom types, various water depths from 1-3.3m and sets with and without bycatch. We then used the modified purse seine to sample fishes at 550 randomly selected sites in Tampa Bay from January 1997 to December 1998. Sampled habitats ranged from 1.0 to 3.3 m deep and included seagrass beds and non-vegetated sand or mud bottoms. Benthic, demersal, and pelagic fishes were captured, indicating the purse seine effectively sampled the entire water column. A wide size range of fishes was collected including pre-recruitment sizes of several economically important species. The ability of purse seines to fish independent of adjacent shorelines allowed us to sample nearshore waters that included large expanses of sea grass meadow

    Combatting electoral traces: the Dutch tempest discussion and beyond

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    In the Dutch e-voting debate, the crucial issue leading to the abandonment of all electronic voting machines was compromising radiation, or tempest. Other countries, however, do not seem to be bothered by this risk. In this paper, we use actor-network theory to analyse the socio-technical origins of the Dutch tempest issue in e-voting, and its consequences for e-voting beyond the Netherlands. We introduce the term electoral traces to denote any physical, digital or social evidence of a voter's choices in an election. From this perspective, we provide guidelines for risk analysis as well as an overview of countermeasures

    Farm poultry management : for 4-H poultry projects I and II

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    Accompanied by: Leader's guide : 4-H poultry project (to be used with Circular 75), March, 1945.Cover title.Includes "4-H Record" at end.I. Young stock production -- II. Flock management

    Spatial and Size Distribution of Red Drum Caught and Released in Tampa Bay, Florida, and Factors Associated with Post-Release Hooking Mortality

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    The recreational fishery for red drum (Sciaenops ocellatus) in Florida is unusual in that most red drum targeted are immature and caught within estuarine waters. Current state regulations rely exclusively on bag and size limits, resulting in the release of a large proportion of captured individuals. This study employed hook-and-line sampling conducted monthly in Tampa Bay, Florida and catch-and-release mortality experiments to determine the spatial and size distribution of red drum and the mortality rate of released fish, respectively. Of the 1,405 red drum collected, more than 70% were smaller than the minimum legal size (457 mm standard length (SL)). Size structure of red drum varied spatially and reflected ontogenetic patterns of habitat use. Data collected during catch-and-release mortality experiments were analyzed to identify factors associated with mortality. A total of 251 red drum (203-618 mm SL) were caught and held for 48 h during 9 experiments, with an overall mortality rate of 5.6%. Higher water temperature and anatomical hook position were significantly correlated with mortality; lip-hooked fish had the lowest mortality rate, while throat-hooked fish had the highest. Although hook type was not correlated with mortality, it did influence whether a fish was deep-hooked. Fish caught by J-hooks were more likely to be deep-hooked than those caught by circle hooks. Catch-and-release fishing is an effective management tool for reducing take but may contribute to short-term mortality, especially in warm, subtropical estuaries

    Complex spatial language improves from 3 to 5 years: The role of prompting and overhearing in facilitating direction giving using between and middle.

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    The primary goal of this study was to specify age-related improvements in young children’s use of the complex spatial terms between and middle in response to prompting and overhearing supports. Three- to 5-year-old children described the location of a mouse hidden between two furniture items in a dollhouse. Three prompting conditions (Between Directive, Middle Directive, Nondirective) were compared with two overhearing conditions (Overhearing Between, Overhearing Middle). Children’s use of between and middle was much more frequent in response to directive prompting than in response to nondirective prompting or overhearing. Only 4-5-year-old children showed some evidence of using middle in response to nondirective prompting and overhearing, demonstrating developmental gains in sensitivity to subtle cues. The secondary goal was to assess young children’s production and comprehension of between and middle using tasks suitable for young children and parent report checklists. As expected, children’s spatial language showed strong developmental improvement and was related to direction-giving performance

    Conceptualising connections: energy demand, infrastructures and social practices

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    Problems of climate change present new challenges for social theory. In this paper we focus on the task of understanding and analysing car dependence, using this as a case through which to introduce and explore what we take to be central but underdeveloped questions about how infrastructures and complexes of social practice connect across space and time. In taking this approach we work with the proposition that forms of energy consumption, including those associated with automobility, are usefully understood as outcomes of interconnected patterns of social practices, including working, shopping, visiting friends and family, going to school and so forth. We also acknowledge that social practices are partly constituted by, and always embedded in material arrangements. Linking these two features together we suggest that forms of car-dependence emerge through the intersection of infrastructural arrangements that are integral to the conduct of many practices at once. We consequently explore the significance of professional – and not only ‘ordinary’ – practices, especially those of planners and designers who are involved in reconfiguring infrastructures of different scales, and in the practice dynamics that follow

    Poultry management : for 4-H poultry projects

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    November, 1952."University of Missouri College of Agriculture and the United States Department of Agriculture Cooperating"--Page 47.Title from caption

    Effects of preservation methods of muscle tissue from upper-trophic level reef fishes on stable isotope values (δ13C and δ15N)

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    © The Author(s), 2015. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in PeerJ 3 (2015): e874, doi:10.7717/peerj.874.Research that uses stable isotope analysis often involves a delay between sample collection in the field and laboratory processing, therefore requiring preservation to prevent or reduce tissue degradation and associated isotopic compositions. Although there is a growing literature describing the effects of various preservation techniques, the results are often contextual, unpredictable and vary among taxa, suggesting the need to treat each species individually. We conducted a controlled experiment to test the effects of four preservation methods of muscle tissue from four species of upper trophic-level reef fish collected from the eastern Gulf of Mexico (Red Grouper Epinephelus morio, Gag Mycteroperca microlepis, Scamp Mycteroperca phenax, and Red Snapper Lutjanus campechanus). We used a paired design to measure the effects on isotopic values for carbon and nitrogen after storage using ice, 95% ethanol, and sodium chloride (table salt), against that in a liquid nitrogen control. Mean offsets for both δ13C and δ15N values from controls were lowest for samples preserved on ice, intermediate for those preserved with salt, and highest with ethanol. Within species, both salt and ethanol significantly enriched the δ15N values in nearly all comparisons. Ethanol also had strong effects on the δ13C values in all three groupers. Conversely, for samples preserved on ice, we did not detect a significant offset in either isotopic ratio for any of the focal species. Previous studies have addressed preservation-induced offsets in isotope values using a mass balance correction that accounts for changes in the isotope value to that in the C/N ratio. We tested the application of standard mass balance corrections for isotope values that were significantly affected by the preservation methods and found generally poor agreement between corrected and control values. The poor performance by the correction may have been due to preferential loss of lighter isotopes and corresponding low levels of mass loss with a substantial change in the isotope value of the sample. Regardless of mechanism, it was evident that accounting for offsets caused by different preservation methods was not possible using the standard correction. Caution is warranted when interpreting the results from specimens stored in either ethanol or salt, especially when using those from multiple preservation techniques. We suggest the use of ice as the preferred preservation technique for muscle tissue when conducting stable isotope analysis as it is widely available, inexpensive, easy to transport and did not impart a significant offset in measured isotopic values. Our results provide additional evidence that preservation effects on stable isotope analysis can be highly contextual, thus requiring their effects to be measured and understood for each species and isotopic ratio of interest before addressing research questions.Funding was provided by a grant to CD Stallings and TS Switzer from the National Oceanic and Atmospheric Administration, Cooperative Research Program (NA12NMF4540081)

    Digital activism: After the hype

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    Research on digital activism has gained traction in recent years. At the same time, it remains a diverse and open field that lacks a coherent mode of inquiry. For the better or worse, digital activism remains a fuzzy term. In this introduction to a special issue on digital activism, we review current attempts to periodize and historicize digital activism. Although there is growing body of research on digitial activism, many contributions remain limited through their ahistorical approach and the digital universalism that they imply. Based on the contributions to the special issue, we argue for studying digital activisms in a way that traverses a two-dimensional axis of digital technologies and activist practices, striking the balance between context and media-specificity
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