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61.
62.
The phytoplankton population from a station in the Jellicoe Channel area of the Hauraki Gulf, New Zealand, was fairly constant, in terms of total population and species composition, throughout the year. Correspondence analysis enabled us to identify 3 groups of species. The largest of these comprised the core species which were present most of the time and included some, such as the coccolithophores, with a strongly seasonal occurrence. The species in the second group were mainly large centric diatoms and appeared for short periods during the winter months, apparently brought in by incursions of oceanic water. The third group of species occurred between April 1970 and October 1971 when there was a period of unusually warm weather: the winds were lighter and more often blowing onshore and this perhaps led to warmer, less nutrient‐rich surface waters being brought into the Gulf. 相似文献
63.
Movement patterns of individual migrating western rock lobster,Panulirus cygnus,in Western Australia
Abstract Migrating and pre‐migrating western rock lobster Panulirus cygnus were tagged with datastorage tags that recorded temperature and pressure, which was converted to depth (Pressure (kPa) — surface pressure (kPa)/10)) at Dongara and Jurien Bay in Western Australia between December 2005 and December 2007. All lobsters were fitted with tag flotation devices, and returns were made by either commercial fishers or beachcombers who located detached tags. A total of 135 lobsters were released with “backpack” flotation tags, but only 84 (62.2%) of the backpacks carried data‐storage tags. Depths of release ranged from 5 to 113 m. Of the tagged lobsters released, commercial fishers recaptured 52 (38.5%), whereas 11 tags (8.1%) were found by beachcombers. At least 33%, and possibly up to 63%, of animals identified by their pale coloration as pre‐migrating individuals, failed to migrate. Those that did migrate (n = 11) were at liberty from 1 to 94 days and showed generally similar movement patterns in that they migrated only at night from darkness (after 2000 h) until after moonrise. However, their movement patterns were less constrained by the rising of the moon in deep water. Only 27% migrated nightly, compared with 73% that skipped migrating on one or more nights, to restart some days later. This latter proportion would likely have been considerably greater, but some migrating animals were only at large for short periods before recapture, and therefore had little time to show any variation to the nocturnal migration pattern. Individual speeds of migration during periods of activity were estimated for nine lobsters as 0.20 to 0.68 km h?1, with a mean speed of 0.44 km h?1, or 7.4 m min?1. Improved knowledge of daily movement patterns resulting from this study provides a potentially important input into technological improvements in bait and pot design. 相似文献
64.
This paper addresses oil spill detection from remotely sensed optical images. In particular, it focuses on the automatic classification
of regions of interest (ROIs) in two classes, namely oil spills or look-alikes. Candidate regions and the corresponding boundaries
have been manually identified from full resolution Moderate Resolution Imaging Spectroradiometer images, related to the Mediterranean
Sea over the years 2008 and 2009. Then, a set of features has been extracted from each ROI, allowing to formulate the oil
spill detection problem as a two-class classification task on the provided regions (i.e. using a supervised learning strategy).
Since ROI classification is challenging, some desired characteristics for the classification algorithm are first identified,
such as accuracy, robustness, etc. Then, a solution (called SVME) is provided: it is based on an ensemble of incremental/decremental
cost-oriented Support Vector Machines, aggregated with the Receiving Operating Characteristic (ROC) convex hull method in
the ROC space. Such a solution addresses all the desired characteristics. Finally, the results obtained on the collected dataset
are shown. The importance of this study is the devising of a powerful classification technique that may have an impact on
optical oil spill detection from space, especially if fused with satellite synthetic aperture radar data. Moreover, it is
shown how the proposed system can be used as a decision support tool, to help a junior operator in making more reliable detections. 相似文献
65.
We report here the first documented case of a cetacean fatality from entanglement in recreational Spectra® fishing twine. Spectra® twine is a relatively new microfilament braided twine that is marketed to replace nylon monofilament twine in rod and reel fisheries. Following the case of this entangled bottlenose dolphin (Tursiops truncatus), we conducted tests with Spectra® and comparable monofilament twines on Tursiops tissue from stranded animals to compare the abrasion properties of the twines. We found that Spectra® twine was significantly more abrasive on bottlenose dolphin fluke tissue than a similar strength and diameter monofilament. With the same forces applied, the Spectra® twine cut deeper than the monofilament, exhibiting a linear relationship with force applied where the monofilament appeared to reach a maximum depth of penetration of approximately 2 mm. These tests may explain why this bottlenose dolphin was so severely debilitated from carrying a relatively light load of twine over a short period of time (20 days). Future public and corporate outreach will be essential to minimize the effect that this increasingly popular fishing twine will have on non-target species. 相似文献
66.
Linda Giresini 《Bulletin of Earthquake Engineering》2016,14(3):919-942
Seismic vulnerability of historic churches is a well known issue in earthquake engineering. The need of preserving these buildings encourages the development of reliable numerical methods to assess their seismic behavior. In this paper a new approach is presented, based on evaluating damage pattern obtained by non-linear dynamic analysis and the energy dissipated by each macro-element during earthquakes. A “hierarchy of dissipated energy” concept emerges to give a scale of vulnerability of the parts that compose a church. By modifying masonry mechanical parameters or geometric features, the crack pattern and amount of energy dissipation density of each element is varied and calibrated to achieve the desired hierarchy. The structural designer can therefore estimate the effectiveness of strengthening devices by checking reduction and possibly migration of dissipated energy density from weaker structural elements to more resistant ones, together with a preferable damage pattern. The proposed strategy is applied to a single nave church, hit by the Emilia Romagna earthquake (Italy, 2012), first defining a scale of vulnerability of the macro-elements and then proposing a rehabilitation strategy, which improves the seismic response in terms of damages and dissipated energy. The strong vulnerability of the main dome vault is shown, due to the combination of its high dissipated energy density with its intrinsic weakness. Strengthening techniques are aimed to reduce the amount of dissipated energy of vulnerable macro-elements and to attenuate out-of-plane mechanisms. 相似文献
67.
Demetris Demetriou Linda See John Stillwell 《International journal of geographical information science》2013,27(12):2391-2409
Land fragmentation is a widespread situation which may often hinder agricultural development. Land consolidation is considered to be the most effective land management planning approach for controlling land fragmentation and hence improving agricultural efficiency. Land partitioning is a basic process of land consolidation that involves the subdivision of land into smaller sub-spaces subject to a number of constraints. This paper explains the development of a module called LandParcelS (Land Parcelling System) that is a part of an integrated planning and decision support system called LACONISS (LAndCONsolidation Integrated Support System) which has been developed to assist land consolidation planning in Cyprus. LandParcelS automates the land partitioning process by designing and optimising land parcels in terms of their shape, size and value. The methodology integrates geographical information systems and a genetic algorithm that has been applied to two land blocks that are part of a larger case study area in Cyprus. Partitioning is treated as either a single or multi-objective problem for various optimisation cases. The results suggest that a step forward has been made in solving this complex spatial problem, although further research is needed to improve the algorithm. This approach may have relevance to other spatial planning tasks that involve single or multi-objective optimisation problems, especially those dealing with space partitioning. 相似文献
68.
Recently a national 3D standard was established in the Netherlands as a CityGML Application Domain Extension (called IMGeo). In line with the Dutch practice of modeling geo‐information, the ADE is developed using a model driven approach. The classes are designed in UML and automatically mapped to GML schema. The current OGC CityGML specification does not provide rules or guidance on correctly modeling an ADE in UML. This article fills this gap by studying how CityGML can be extended for specific applications starting from the UML diagrams. Six alternatives for modeling ADEs in UML are introduced and compared. The optimal alternative is selected and applied to obtain the national 3D standard. The approach was extensively discussed with international experts, who were members of both SIG3D and other working groups. As a consequence the approach was adopted by the SIG3D, the Special Interest Group 3D which, among other things, work on the 3D standard CityGML in cooperation with OGC. Therefore the approach contains many issues that can be generalized and reused by future domain extensions of CityGML. To further support this, the article formulates a model‐driven framework to model CityGML ADEs. Open issues are described in the conclusions. 相似文献
69.
Almost all engineering evacuation models define the objective as minimizing the time required to clear the region or total
travel time, thus making an implicit assumption that who will or should evacuate is known. Conservatively evacuating everyone
who may be affected may be the best strategy for a given storm, but there is a growing recognition that in some places that
strategy is no longer viable and in any case, may not be the best alternative by itself. Here, we introduce a new bi-level
optimization that reframes the decision more broadly. The upper level develops an evacuation plan that describes, as a hurricane
approaches, who should stay and who should leave and when, so as to minimize both risk and travel time. The lower level is
a dynamic user equilibrium (DUE) traffic assignment model. The model includes four novel features: (1) it refocuses the decision
on the objectives of minimizing both risk and travel time; (2) it allows direct comparison of more alternatives, including
for the first time, sheltering-in-place; (3) it uses a hurricane-scenario-based analysis that explicitly represents the critically
important uncertainty in hurricane track, intensity, and speed; and (4) it includes a new DUE algorithm that is efficient
enough for full-scale hurricane evacuation applications. The model can be used both to provide an evacuation plan and to evaluate
a plan’s performance in terms of risk and travel time, assuming the plan is implemented and a specified hurricane scenario
then actually occurs. We demonstrate the model with a full-scale case study for Eastern North Carolina. 相似文献
70.
Assunta Florenzano Anna Maria Mercuri Aurora Pederzoli Paola Torri Giovanna Bosi Linda Olmi Rossella Rinaldi Marta Bandini Mazzanti 《Geoarchaeology》2012,27(1):34-47
This paper presents the study of parasite remains recovered in pollen samples collected from archaeological layers. Laboratory treatment enabled us to obtain very high concentrations of both pollen and parasite eggs from the same samples. The case study of the site of Piazza Garibaldi in Parma, a town in the Po plain, is reported. The site was a sacred area in Roman times and a market square in Medieval times (10th–11th century A.D.). Pollen, seeds, and fruits from the latter phase were collected from four Medieval pits and one cesspit. After a palynological treatment including sieving, floating, and light acetolysis, abundant quantities of parasite eggs were extracted. Human and animal parasite eggs belonging to Trichuris, Ascaris, Taenia/Echinococcus, Capillaria, Dicrocoelium, and Diphyllobothrium were found. The analyses of animal and plant remains identified in the same samples suggested that the pit infillings consisted of waste, human and animal excrements, deteriorated plant food, and refuse of grapes. Therefore, parasite remains help the interpretation of archaeobotanical data in identifying human behaviors and site functions. 相似文献