Performance of the LHCb RICH detector at the LHC Adinolfi, M.; Aglieri Rinella, G.; Albrecht, E. ...
The European physical journal. C, Particles and fields,
05/2013, Letnik:
73, Številka:
5
Journal Article
Recenzirano
Odprti dostop
The LHCb experiment has been taking data at the Large Hadron Collider (LHC) at CERN since the end of 2009. One of its key detector components is the Ring-Imaging Cherenkov (RICH) system. This ...provides charged particle identification over a wide momentum range, from 2–100 GeV/
c
. The operation and control, software, and online monitoring of the RICH system are described. The particle identification performance is presented, as measured using data from the LHC. Excellent separation of hadronic particle types (
π
, K, p) is achieved.
During the last century, there has been a steady decline in the global breeding population of
Eudyptes chrysocome chrysocome
, and this species has been exposed to many different threats. However, ...the small breeding population of Isla Pingüino, Argentina, increased since its discovery in 1985 until 1990. To determine whether this population continued to grow, we assessed its trend over a 30-year period and estimated its breeding success. This study shows a strong increase in the population in Isla Pingüino with an annual growth rate of more than 7 %, throughout the 30-year study period. The threats that are affecting seabird populations in other areas seem to have no negative effects on this breeding population. In particular, tourism, which has grown exponentially during the survey period, appears to not have had a negative effect on the settlement of new pairs, the number of breeding pairs and their breeding success. We suggest that the population increase in Isla Pingüino might have been facilitated by an immigration of breeding adults from nearby breeding sites such as Falkland Islands (Malvinas).
Penguins are the most threatened group of seabirds after albatrosses. Although penguins are regularly captured in fishing gear, the threat to penguins as a group has not yet been assessed. We ...reviewed both published and grey literature to identify the fishing gear types that penguins are most frequently recorded in, the most impacted species and, for these susceptible species, the relative importance of bycatch compared to other threats. While quantitative estimates of overall bycatch levels are difficult to obtain, this review highlights that, of the worldís 18 species of penguins, 14 have been recorded as bycatch in fishing gear and that gillnets, and to a lesser extent trawls, are the gear types that pose the greatest threats to penguins. Bycatch is currently of greatest concern for yellow-eyed Megadyptes antipodes (Endangered), Humboldt Spheniscus humboldti (Vulnerable) and Magellanic Spheniscus magellanicus penguins (Near Threatened). Penguins face many threats; reducing bycatch mortality in fishing gear will greatly enhance the resilience of penguin populations to threats from habitat loss and climate change that are more difficult to address in the short term. Additional data are required to quantify the true extent of penguin bycatch, particularly for the most susceptible species. In the meantime, it is crucially important to manage the fisheries operating within known penguin foraging areas to reduce the risks to this already threatened group of seabirds.
In diving seabirds, sexual dimorphism in size often results in sex-related differences of foraging patterns. Previous research on Magellanic penguins, conducted during the breeding season, failed to ...reveal consistent differences between the sexes on foraging behavior, despite sexual dimorphism. In this paper, we tested the hypothesis that male and female Magellanic penguins differ in diet and foraging patterns during the non-breeding period when the constraints imposed by chick rearing activities vanish. We used stable isotope ratios of carbon and nitrogen in feather and bone to characterize the diet and foraging patterns of male and female penguins in the South Atlantic at the beginning of the 2009–2010 and 2010–2011 post-breeding seasons (feathers) and over several consecutive breeding and migratory seasons (bone). The mean δ
13
C and δ
15
N values of feathers showed no differences between the sexes in any of the three regions considered or in the diet composition between the sexes from identical breeding regions; however, Bayesian ellipses showed a higher isotopic niche width in males at the beginning of the post-breeding season. Stable isotope ratios in bone revealed the enrichment of males with δ
13
C compared with females across the three regions considered. Furthermore, the Bayesian ellipses were larger for males and encompassed those of females in two of the three regions analyzed. These results suggest a differential use of winter resources between the sexes, with males typically showing a larger diversity of foraging/migratory strategies. The results also show that dietary differences between male and female Magellanic penguins may occur once the constraints imposed by chick rearing activities cease at the beginning of the post-breeding season.
This study investigated the level of seabird mortality caused by the domestic trawl fleet (freshies) for hake (among other less important targets) operating in waters off central Patagonia (37-48°S), ...analyzing the effect of environmental and operational variability on the level of seabird interactions. With a total of 135 vessels, the fleet is one of the largest in Argentina. Specifically tasked seabird observers were placed onboard trawlers during the summer and winter seasons of the years 2006 and 2007. The type and number of seabird interactions (i.e. contacts with fishing gear) were recorded during shooting and hauling operations, covering 72 days of observation and 328 trawls. Black-browed albatrosses, white-chinned petrels Procellaria aequinoctialis, southern giant petrels Marconectes giganteus and southern royal albatrosses Diomedea epomophora were the most abundant species interacting with trawlers. Confirmed mortalities of black-browed and southern royal albatrosses were the result of collisions and entanglement with the warp cable while birds were scavenging. The estimated total mortality rate was 0.017 birds h⁻¹ and 0.105 birds per vessel per day. The intensity of interactions (in terms of the number of contacts per unit time) was largely explained by the distribution of the fishing effort. Seasonality and the incidence of discards were the strongest factors explaining the occurrence of seabird interactions. The total annual mortality in the trawl fleet under investigation was roughly estimated to be from several hundred to over a thousand albatrosses. However, these figures should be considered preliminary due to the limited spatial and temporal coverage of data and the fact that estimations were based on a low number of observed mortalities. The implementation of a strategic discard management may significantly reduce the number of seabird mortalities from collisions with warp cables or improve the effectiveness of other complementary mitigation methods. Urgent implementation of mitigation measures is needed in this fleet to reduce the mortality of albatrosses and petrels along the Patagonian shelf.
Incidental mortality of seabirds caused by longline fisheries in the south-western Atlantic Ocean has been assessed only with reference to the number of birds caught, not taking into account how the ...configuration of the gear affects mortality. We provide the first direct estimates of the impact on seabirds of the semi-pelagic fishing gear used in the Argentine Kingclip
Genypterus blacodes fishery. The gear included weights and buoys, sequentially spaced along the lines, which enabled fishing to occur at different depths. During a fishing trip onboard the F/V
Argenova XII in the austral summer of 2005, 74 birds were captured, comprising 56 White-chinned petrels
Procellaria aequinoctialis and 18 Black-browed albatrosses
Thalassarche melanophrys. More than half of the hooked birds were caught in the first third of the lines being set, and almost all White-chinned petrels (96%) and Black-browed albatrosses (83%) were caught within 30
m (i.e. 24 hooks) of buoys. The floats used in semi-pelagic longlines are likely to decrease the sinking rates of baited hooks near them, buoying up the lines near the surface and increasing the likelihood of seabird interactions. Although we lack information on the distribution of captured fish along these longlines, the most feasible methods to reduce seabird bycatch in the Argentine semi-pelagic longline fishery would be (1) to deploy lines without hooks near line floats (the removal of 24 hooks either side of each float should substantially reduce seabird interactions with gear) or (2) to use long snoods between the mainline and the floats, allowing the baited hooks to quickly sink beyond the reach of seabirds.
We analyzed the effect of the shrimp fishery on Magellanic Penguins (Spheniscus magellanicus) in two ways: (1) we determined whether penguins were incidentally killed and the magnitude of incidental ...take, and (2) estimated the overlap between penguin diet and fish by-catch of the shrimp fishery (total capture excluding shrimp and seabirds). We worked with the fishing fleet operating at Golfo San Jorge with onboard observers over 200 days in 1995-1997, sampling fishery by-catch and entangled birds. Penguins were affected during the austral summer. Estimations of mortality rates showed 0.33% of the breeding population at Golfo San Jorge is incidentally killed by the shrimp fishery every summer. By-catch in shrimp fishery nets was composed of species important as penguin prey (anchovy and hake) in higher proportions during summer. The daily by-catch of these species was higher than the total calculated daily intake for all penguins breeding in the Golfo San Jorge. This could have a significant effect on birds. We recommend that an observer program be implemented to monitor seabird mortality and that fishing gear should be improved to reduce the indirect effect of the fish by-catch on penguins.
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