Dispersion and abundance of Maritrema arenaria in Semibalanus balanoides in north-east Ireland

1990 ◽  
Vol 64 (2) ◽  
pp. 151-160 ◽  
Author(s):  
H. Carrol ◽  
W. I. Montgomery ◽  
R. E. B. Hanna
Keyword(s):  
Size Structure ◽  
Background Level ◽  
Host Population ◽  
Parasite Infection ◽  
Semibalanus Balanoides ◽  
Low Background ◽  
Digenean Trematode ◽  
North East ◽  
Parasitic Burden ◽  
A Site

ABSTRACTInfection of the barnacle Semibalanus balanoides with the digenean trematode Maritrema arenaria was investigated at 17 sites along the Co. Down coastline. There was a low background level of infection. Abundance of M. arenaria, however, was substantially greater at sites close to fish factories and at a site close to a sewage works. Aggregation of M. arenaria in S. balanoides was least marked at low mean parasite burdens. The parasitic burden was related more closely to barnacle size at a site of heavy infection than at one with a low abundance. There was a significant association between height on the shore and number of encysted metacercariae in S. balanoides. This was independent of variation in host size. It is concluded that relationships that bring about overdispersion of digeneans, such as that between the size-structure of the host population and parasite infection, may be dependent on the overall abundance of the parasite.

scholarly journals The therapeutic effect of a person staying in a salt mine due to the low background level of atomic radiation

2020 ◽  
Vol 17 (5) ◽  
pp. 279-283
Author(s):  
Gayaz H. Harisov ◽  
Aleksander G. Zavorotny
Keyword(s):  
Experimental Study ◽  
Therapeutic Effect ◽  
Salt Spray ◽  
Background Level ◽  
Salt Mine ◽  
Low Background ◽  
Salt Mines ◽  
Low Levels

The therapeutic effect of people staying in salt mines is currently explained by the fact that people inhale salt spray particulates. Based on an experimental study, the article proves that this therapeutic effect is the result of super-low levels of atomic radiation in the space of salt mines.

scholarly journals The effects of temporary exclusion of activity due to wind farm construction on a lobster (Homarus gammarus) fishery suggests a potential management approach

2018 ◽  
Vol 75 (4) ◽  
pp. 1416-1426 ◽  
Author(s):  
Michael Roach ◽  
Mike Cohen ◽  
Rodney Forster ◽  
Andrew S Revill ◽  
Magnus Johnson
Keyword(s):  
Wind Farm ◽  
Size Structure ◽  
Wind Farms ◽  
Offshore Wind ◽  
Ecological Effect ◽  
Fishing Ground ◽  
Management Approach ◽  
Homarus Gammarus ◽  
North East ◽  
Temporary Closure

Abstract Offshore wind farms (OWF) form an important part of many countries strategy for responding to the threat of climate change, their development can conflict with other offshore activities. Static gear fisheries targeting sedentary benthic species are particularly affected by spatial management that involves exclusion of fishers. Here we investigate the ecological effect of a short-term closure of a European lobster (Homarus gammarus (L.)) fishing ground, facilitated by the development of the Westermost Rough OWF located on the north-east coast of the United Kingdom. We also investigate the effects on the population when the site is reopened on completion of the construction. We find that temporary closure offers some respite for adult animals and leads to increases in abundance and size of the target species in that area. Reopening of the site to fishing exploitation saw a decrease in catch rates and size structure, this did not reach levels below that of the surrounding area. Opening the site to exploitation allows the fishery to recuperate some of the economic loss during the closure. We suggest that our results may indicate that temporary closures of selected areas may be beneficial and offer a management option for lobster fisheries.

Large-scale patterns in habitat structure on subtidal rocky reefs in New South Wales

2000 ◽  
Vol 51 (3) ◽  
pp. 255 ◽  
Author(s):  
N. L. Andrew ◽  
A. L. O'Neill
Keyword(s):  
Sea Urchin ◽  
Geographical Information Systems ◽  
Large Scale ◽  
Size Structure ◽  
New South ◽  
New South Wales ◽  
Geographical Information ◽  
South Wales ◽  
Subtidal Rocky Reefs ◽  
A Site

Aerial photography was used to estimate the representation of shallow subtidal habitats in New South Wales. Sixty sites, each between 4 and 5 hectares, were mapped with Geographical Information Systems software using ortho-rectified images digitized from 1:8000-scale photographs and ‘ground truthed’ in the field by divers. Barrens habitat covered an estimated 50% (s.e. = 3.9) of nearshore reefs between Port Stephens and Disaster Bay. Coverage of barrens habitat was greatest in Disaster Bay (68%, s.e. = 6.7) and least south of Disaster Bay (1%, s.e. = 0.3). There were clear differences among localities in the area of reef within the mapped sites; those at Cape Howe, Nadgee, and Turingal were significantly smaller in area than all others. There was no clear latitudinal trend in these differences but there was evidence of sand inundation at a site at Nadgee, where the reef was small. Differences in the densities and size-structure of the sea urchin Centrostephanus rodgersiiat 27 of the mapped sites provide a basis for testing relationships between the demography of this species and the persistence of the barrens habitat. The extensive coverage of the barrens habitat in New South Wales is likely to limit the productivity of the abalone industry. The development of a sea urchin fishery may have large impacts on habitat representation on nearshore reefs.

Underground low-background-level laboratory for radiogeochemical investigations

1984 ◽  
Vol 57 (3) ◽  
pp. 633-637
Author(s):  
Yu. A. Surkov ◽  
O. P. Sobornov ◽  
O. P. Shcheglov ◽  
G. Sh. Shengelaya ◽  
K. K. Daneliya ◽  
...  
Keyword(s):  
Background Level ◽  
Low Background

THE FINAL STAGE OF NINEVITE 5 POTTERY: MORPHOLOGICAL TYPES, TECHNOLOGY AND DIACHRONIC ANALYSIS FROM TELL ARBID (NORTH-EAST SYRIA)

Iraq ◽  
2016 ◽  
Vol 78 ◽  
pp. 175-214
Author(s):  
Anna Smogorzewska
Keyword(s):  
Final Stage ◽  
Economic Factors ◽  
Pottery Production ◽  
Internal Development ◽  
North East ◽  
Diachronic Analysis ◽  
A Site

This paper presents major trends in pottery development in the final Ninevite 5 period, which corresponds to the final EJZ 2 period in the Syrian Jezirah. This discussion is based primarily on a pottery assemblage from Tell Arbid, a site in north-east Syria. The pottery was recovered from a dwelling quarter (Area D), where both final Ninevite 5 (final EJZ 2) and post-Ninevite 5 (EZJ 3) occupation were recognized. Excavations at Tell Arbid have provided new data regarding the late Ninevite 5 pottery repertoire and its internal development. Morphological types of vessels and their technology are discussed at length. Major traits of the final Ninevite 5 pottery are recognized and defined, including pottery “index fossils” as well as some less distinct pottery types. Chronological variability of pottery types has also been traced, special attention being given to continuity and changes in pottery production between final Ninevite 5 and post-Ninevite 5 (EJZ 3) periods. A trend toward standardization visible in the final Ninevite 5 pottery development is related to political and economic factors in the Syrian Jezirah at this time.

scholarly journals Excavations in Melos, 1897

1897 ◽  
Vol 3 ◽  
pp. 1-30 ◽  
Author(s):  
Cecil Smith
Keyword(s):  
North East ◽  
The North ◽  
British School ◽  
A Site

At the close of last year's Report (British School Annual, vol. ii., p. 76) it was stated that we had begun late in the season of 1896 an excavation on a site at Phylakopi, in the north-east of the island. The results then obtained were of so promising a character, that it was determined to constitute Phylakopi as the main objective of the campaign of 1897, and in fact to lay siege to the prehistoric fortress with all the forces at our disposition.

scholarly journals The Remnant Leiopelma Pakeka (Anura: Leiopelmatidae) Population on Maud Island: Population Size, Distribution and Morphology

2021 ◽  
Author(s):  
◽  
Jacqueline Valerie Phoebe Le Roux
Keyword(s):  
Population Size ◽  
Size Structure ◽  
Vegetation Type ◽  
Bootstrap Method ◽  
Island Population ◽  
The South ◽  
North East ◽  
Forest Remnant ◽  
Population Size Estimates ◽  
Recent Estimate

<p>Leiopelma pakeka is an archaic frog native to New Zealand, and until recently was restricted to a 15ha forest remnant on the south-east face of Maud Island. The L.pakeka population appears to be growing and spreading out from the forest remnant. This study investigated the population size, structure, and distribution of L. pakeka on Maud Island in 2006. The forest remnant was searched using 106 randomly placed 25m2 plots. Population size was estimated using a bootstrap method repeated 10,000 times, adjusted for likelihood of emergence, likely maximum plot population size, and area. The average population size was 34,449 frogs, which is much higher than a 1994 minimum number alive estimate of 19,312. The new figure, however, is similar to another recent estimate of 39,563, based on an update of the 1994 figure. Distributional patterns within the forest remnant were similar to the 1994 study, with most frogs between 90-170m above sea level. The comparability of the population size estimates indicates that L. pakeka numbers have reached the carrying capacity of the forest remnant. The distribution of the remnant L. pakeka population was determined by thoroughly searching the south-east face of Maud Island, thereby minimising the possibility of missing frogs. A total of 232 frogs were found. Frogs generally colonised areas within 50m of the remnant; movement was greater in regenerating forest (75m in the southwest and 100m in the north east) than in pastoral areas (<25m). The size of frogs increased with distance from the forest remnant (weight, girth, condition index, and average snout-vent and tibio-fibula lengths). The size increases may be indications of competitive release, as frog density decreased with distance from the forest remnant. The size range of Leiopelma pakeka was extended by the current study from 50.5mm to at least 52mm snout-vent length. A total of 15 L. pakeka were found on Fort Road, approximately 350m from the remnant. These frogs were most likely in the area before 1994. The Fort Road frogs were compared to the forest remnant L. pakeka, and were not morphologically distinct as only patterning differed significantly. Fort Road L. pakeka may belong to a separate subpopulation. L. pakeka distribution was significantly affected by habitat. Important variables were vegetation type, and rock, canopy, sub-canopy, and leaf litter cover. The size of emergent frogs (tibio-fibula length) was significantly and positively correlated with relative humidity.</p>

scholarly journals The Remnant Leiopelma Pakeka (Anura: Leiopelmatidae) Population on Maud Island: Population Size, Distribution and Morphology

2021 ◽  
Author(s):  
◽  
Jacqueline Valerie Phoebe Le Roux
Keyword(s):  
Population Size ◽  
Size Structure ◽  
Vegetation Type ◽  
Bootstrap Method ◽  
Island Population ◽  
The South ◽  
North East ◽  
Forest Remnant ◽  
Population Size Estimates ◽  
Recent Estimate

<p>Leiopelma pakeka is an archaic frog native to New Zealand, and until recently was restricted to a 15ha forest remnant on the south-east face of Maud Island. The L.pakeka population appears to be growing and spreading out from the forest remnant. This study investigated the population size, structure, and distribution of L. pakeka on Maud Island in 2006. The forest remnant was searched using 106 randomly placed 25m2 plots. Population size was estimated using a bootstrap method repeated 10,000 times, adjusted for likelihood of emergence, likely maximum plot population size, and area. The average population size was 34,449 frogs, which is much higher than a 1994 minimum number alive estimate of 19,312. The new figure, however, is similar to another recent estimate of 39,563, based on an update of the 1994 figure. Distributional patterns within the forest remnant were similar to the 1994 study, with most frogs between 90-170m above sea level. The comparability of the population size estimates indicates that L. pakeka numbers have reached the carrying capacity of the forest remnant. The distribution of the remnant L. pakeka population was determined by thoroughly searching the south-east face of Maud Island, thereby minimising the possibility of missing frogs. A total of 232 frogs were found. Frogs generally colonised areas within 50m of the remnant; movement was greater in regenerating forest (75m in the southwest and 100m in the north east) than in pastoral areas (<25m). The size of frogs increased with distance from the forest remnant (weight, girth, condition index, and average snout-vent and tibio-fibula lengths). The size increases may be indications of competitive release, as frog density decreased with distance from the forest remnant. The size range of Leiopelma pakeka was extended by the current study from 50.5mm to at least 52mm snout-vent length. A total of 15 L. pakeka were found on Fort Road, approximately 350m from the remnant. These frogs were most likely in the area before 1994. The Fort Road frogs were compared to the forest remnant L. pakeka, and were not morphologically distinct as only patterning differed significantly. Fort Road L. pakeka may belong to a separate subpopulation. L. pakeka distribution was significantly affected by habitat. Important variables were vegetation type, and rock, canopy, sub-canopy, and leaf litter cover. The size of emergent frogs (tibio-fibula length) was significantly and positively correlated with relative humidity.</p>

scholarly journals Baryon Acoustic Oscillations from Integrated Neutral Gas Observations: Radio Frequency Interference Measurements and Telescope Site Selection

2019 ◽  
Vol 08 (01) ◽  
pp. 1940005 ◽  
Author(s):  
M. W. Peel ◽  
C. A. Wuensche ◽  
E. Abdalla ◽  
S. Antón ◽  
L. Barosi ◽  
...  
Keyword(s):  
Radio Frequency ◽  
Radio Frequency Interference ◽  
Acoustic Oscillations ◽  
North East ◽  
Neutral Gas ◽  
Suitable Site ◽  
Baryon Acoustic Oscillations ◽  
Interference Measurements ◽  
A Site ◽  
Remote Part

The Baryon acoustic oscillations from Integrated Neutral Gas Observations (BINGO) telescope is a new 40[Formula: see text]m class radio telescope to measure the large-angular-scale intensity of H i emission at 980–1260[Formula: see text]MHz to constrain dark energy parameters. As it needs to measure faint cosmological signals at the milliKelvin level, it requires a site that has very low radio frequency interference (RFI) at frequencies around 1[Formula: see text]GHz. We report on measurement campaigns across Uruguay and Brazil to find a suitable site, which looked at the strength of the mobile phone signals and other radio transmissions, the location of wind turbines, and also included mapping airplane flight paths. The site chosen for the BINGO telescope is a valley at Serra do Urubu, a remote part of Paraíba in North-East Brazil, which has sheltering terrain. During our measurements with a portable receiver, we did not detect any RFI in or near the BINGO band, given the sensitivity of the equipment. A radio quiet zone around the selected site has been requested from the Brazilian authorities ahead of the telescope construction.

scholarly journals Prevalence, transmission and intensity of infection by a microsporidian sex ratio distorter in natural Gammarus duebeni populations

Parasitology ◽  
1997 ◽  
Vol 114 (3) ◽  
pp. 231-236 ◽  
Author(s):  
A. M. DUNN ◽  
M. J. HATCHER
Keyword(s):  
Sex Ratio ◽  
Natural Populations ◽  
Infection Intensity ◽  
Host Population ◽  
Parasite Infection ◽  
Parasite Transmission ◽  
Target Tissue ◽  
Intensity Of Infection ◽  
Gonadal Tissue ◽  
Crustacean Host

This is a report of the prevalence, transmission and intensity of infection of a microsporidian sex ratio distorter in natural populations of its crustacean host Gammarus duebeni. Prevalence in the adult host population reflects differences in the intensity of infection in transovarially infected embryos and in adult gonadal tissue. The efficiency of transovarial parasite transmission to young also differs between populations, but this alone is insufficient to explain observed patterns of prevalence. Infection intensity may be important in determining future infection of target tissue in the adult and subsequent transmission to future host generations. We consider patterns of parasite infection in terms of selection on transmission and virulence.

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