Countering low visibility in video survey of an estuarine fish assemblage

2020 ◽  
Vol 26 (2) ◽  
pp. 190 ◽  
Author(s):  
James A. Donaldson ◽  
Paulo Drews Jr ◽  
Michael Bradley ◽  
David L. Morgan ◽  
Ronald Baker ◽  
...  
Keyword(s):  
Image Restoration ◽  
Species Level ◽  
Estuarine Fish ◽  
Tropical Estuaries ◽  
White Balance ◽  
Significant Difference ◽  
Low Visibility ◽  
Average Confidence ◽  
Video Survey ◽  
Restoration Algorithms

Sampling fish communities in tropical estuaries is inherently challenging due to poor visibility and the potential presence of dangerous fauna. We present two strategies for improving the identification of fishes in a turbid tropical estuary using video. The first was to attract species close to the camera by using two different bait types compared with no bait, and the second involved manipulating footage in the postfilming phase. No significant difference was found in the species richness recorded among camera bait treatments (thawed Australian sardines, canned sardines and unbaited), although baited cameras did detect 13 taxa not observed on the unbaited cameras. Three different image restoration algorithms (histogram equalisation, white balance and contrast-limited adaptive histogram equalisation) were compared in processing 22 instances where fish could not be confidently identified to species or genus level. Of these processed clips, five were able to be identified to species level by a panel of four coauthors. Further, two of the three algorithms yielded higher average confidence values for identification at the order, family, genus and species level than when the unprocessed footage was viewed. Image restoration algorithms can partly compensate for a reduction in image quality resulting from turbidity, addressing a key challenge for video-based sampling in estuaries.

Fast Adaptive Iterative Image Restoration Algorithms

1988 ◽  
Author(s):  
Serafim N. Efstratiadis ◽  
Aggelos K. Katsaggelos
Keyword(s):  
Image Restoration ◽  
Restoration Algorithms

scholarly journals Protura (Arthropoda: Hexapoda) in Slovenian caves

2021 ◽  
Vol 50 (1) ◽  
pp. 65-74
Author(s):  
Loris Galli ◽  
Franc Janžekovič ◽  
Peter Kozel ◽  
Tone Novak
Keyword(s):  
Organic Matter ◽  
Environmental Conditions ◽  
New Records ◽  
Species Level ◽  
Statistical Analyses ◽  
Small Class ◽  
Surface Soils ◽  
Significant Difference ◽  
Unidentified Species ◽  
Scarce Data

Protura is a small class of Hexapoda, generally poorly known, and rather scarce data on its occurrence in caves are scattered throughout literature on fauna in caves and in some papers on Protura. Although the cave-dwelling fauna is relatively well studied in Slovenia, published records on Protura are rare. In this paper, data on the occurrence and abundance of Protura in Slovenian caves are considered. Various statistical analyses were performed to compare caves with Protura to those without in 60 intensively monitored cavities to detect any differences in the selected environmental conditions. No significant difference was obtained. Samples collected from 15 caves yielded 286 specimens identified to genus or species level. Ten species were identified: Acerentulus confinis (Berlese, 1908), A. rafalskii Szeptycki, 1979*, Acerentomon affine Bagnall, 1912*, A. balcanicum Ionesco, 1933*, A. italicum Nosek, 1969, A. maius Berlese, 1908*, A. meridionale Nosek, 1960, Acerella muscorum (Ionesco, 1930)*, Eosentomon armatum Stach, 1926*, and E. transitorium Berlese, 1908*. The seven species marked with an asterisk are new records for Slovenia. Two specimens belonging to an unidentified species of the genus Ionescuellum Tuxen, 1960 were also found. As expected, Protura were most abundant at the cave entrance close to the surface, and none of the species were found exclusively in cavities. This suggests that proturans were introduced passively into the cavities via organic matter and surface soils.

scholarly journals HST Image Restoration: Current Capabilities and Future Prospects

1994 ◽  
Vol 158 ◽  
pp. 61-69 ◽  
Author(s):  
Robert J. Hanisch ◽  
Richard L. White
Keyword(s):  
Image Restoration ◽  
Dynamic Range ◽  
Hubble Space Telescope ◽  
Spherical Aberration ◽  
Wide Field ◽  
Secondary Mirror ◽  
Faint Object ◽  
Spread Function ◽  
Restoration Algorithms ◽  
Space Variant

The spherical aberration in the primary mirror of the Hubble Space Telescope causes more than 80% of the light from a point source to be spread into a halo of radius of 2–3 arcsec. The point spread function (PSF) is both time variant (resulting from spacecraft jitter and desorption of the secondary mirror support structure) and space variant (owing to the Cassegrain repeater optics in the Wide Field / Planetary Camera). A variety of image restoration algorithms have been utilized on HST data with some success, although optimal restorations require better modeling of the PSF and the development of efficient restoration algorithms that accommodate a spacevariant PSF. The first HST servicing mission (December 1993) will deploy a corrective optics system for the Faint Object Camera and the two spectrographs and a second generation WF/PC with internal corrective optics. As simulations demonstrate, however, the restoration algorithms developed now for aberrated images will be very useful for removing the remaining diffraction features and optimizing dynamic range in post-servicing mission data.

scholarly journals Fish Assemblage Structure Comparison between Freshwater and Estuarine Habitats in the Lower Nakdong River, South Korea

2020 ◽  
Vol 8 (7) ◽  
pp. 496
Author(s):  
Joo Myun Park ◽  
Ralf Riedel ◽  
Hyun Hee Ju ◽  
Hee Chan Choi
Keyword(s):  
Fish Assemblage ◽  
Fish Assemblages ◽  
Estuarine Fish ◽  
Freshwater Species ◽  
Fish Assemblage Structure ◽  
Nakdong River ◽  
Structure Comparison ◽  
Significant Difference ◽  
Freshwater Habitats ◽  
The Nakdong River

Variabilities of biological communities in lower reaches of urban river systems are highly influenced by artificial constructions, alterations of flow regimes and episodic weather events. Impacts of estuary weirs on fish assemblages are particularly distinct because the weirs are disturbed in linking between freshwater and estuarine fish communities, and migration successes for regional fish fauna. This study conducted fish sampling at the lower reaches of the Nakdong River to assess spatio-temporal variations in fish assemblages, and effects of estuary weir on structuring fish assemblage between freshwater and estuary habitats. In total, 20,386 specimens comprising 78 species and 41 families were collected. The numerical dominant fish species were Tachysurus nitidus (48.8% in total abundance), Hemibarbus labeo (10.7%) and Chanodichthys erythropterus (3.6%) in the freshwater region, and Engraulis japonicus (10.0%), Nuchequula nuchalis (7.7%) and Clupea pallasii (5.2%) in the estuarine site. The fish sampled were primarily small species or the juveniles of larger species at the estuary region, while all life stages of fishes were observed at the freshwater habitats. The diversity patterns of fish assemblages varied greatly according to study site and season, with higher trends at estuarine sites during the warm-rainy season. No significant difference in diversity between freshwater and estuarine sites during the cold-dry season were found. Multivariate analyses of fish assemblage showed spatial and seasonal differences of assemblage structures. Higher effects of between-site variability but not within seasonal variability at each site were observed. Variations in assemblage structures were due to different contributions of dominant species in each habitat. Common freshwater species characterized the fish assemblage in the freshwater region, while marine juveniles were significantly associated with the estuarine habitat. The results from the ecological guild analyses showed distinct ecological roles for freshwater and marine species, and overlapping roles for fish sampled at the fishways. The lower reaches of the Nakdong River are an important ecosystem for both freshwater and marine juveniles. Nakdong River estuarine residents and migrant fishes, however, have been negatively affected by the construction of the weir (gravity dam), due to the obstruction to migration from and to freshwater habitats. Conservation and management policies aimed at minimizing anthropogenic influences on estuary ecosystems should focus on evaluating ecological functions of estuary weirs.

P2754Streptococcal infective endocarditis: distribution of species and their prognosis

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
S Chamat ◽  
A Dahl ◽  
C Hassager ◽  
M Arpi ◽  
L Oestergaard ◽  
...  
Keyword(s):  
Infective Endocarditis ◽  
Electronic Device ◽  
Species Level ◽  
University Hospital ◽  
Heart Valve Disease ◽  
Significant Difference ◽  
Streptococcal Species ◽  
Species Groups ◽  
One Year ◽  
The One

Abstract Background Infective endocarditis (IE) is frequently caused by streptococcal species. However, there is limited knowledge about the relationship between different streptococcal species and IE, and their associated outcomes. Purpose To examine the prevalence of streptococci at species level in IE, and to relate these different species to outcomes. Methods From 2002–2012 we prospectively collected consecutive patients with IE admitted to two tertiary heart centres covering a catchment area of 2.4 million people. The registry comprises 915 IE patients, 366 (40%) with streptococcal IE. Based on phylogenetic relationship, streptococcal species were classified into seven main groups: Mitis, Bovis, Mutans, Anginosus, Salivarius, Pyogenic and Nutritionally Variant Streptococcus (NVS). Classification at species level was not possible in 51 patients, who were excluded. Complications and prognosis of streptococcal IE were compared between the subgroups, and at species level. Results We included 315 patients with streptococcal IE. Mean age was 63 (IQR 52–76) years, and most were men (67%). A total of 115 patients (37%) had a previous heart valve disease, 58 (18%) had a prosthetic valve, 22 (7%) had previously had IE and 29 (9%) had a cardiac electronic device. With 148 episodes (47%) the Mitis group was the most common cause of IE. Other frequent groups were the Pyogenic group and the Bovis group, accounting for 66 (21%) and 51 (16%) of the cases, respectively. Surgery was carried out in 55% (n=173) of all cases. Patients infected with S. pneumoniae or S. agalactiae had a significantly higher rate of surgery, 72.2% (n=13) and 71.9% (n=23) respectively, whereas the Bovis group had a significantly lower rate, 35.5% (n=18) (p=0.048). The aortic valve was infected in 137 patients (43.5%), mitral valve in 105 patients (33.3%) and both valves were infected in 53 patients (16.8%). Twenty patients (6.3%) had right-sided IE, including pacemaker lead IE. There was no significant difference between the species subgroups regarding type of infected valve. Embolization and osteitis were observed in 76 (24.1%) and 30 (9.5%) patients, respectively. There was no significant difference between the species groups, as was the case with mortality: 23 patients (7.3%) died in-hospital and the one-year mortality was 16% (n=50). Distribution of streptococcal IE Conclusion Species of the Mitis group were the most frequent Streptococci causing IE. Patients infected with S. pneumonia or S. agalactiae had significantly higher rate of surgery, and patients infected with S. bovis group had lower rate of surgery. There was no significant difference in rate of complications such as abscesses, embolization, osteitis or mortality between the streptococcal species. Acknowledgement/Funding Supported by grants from Herlev-Gentofte University Hospital Research Foundation

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