Biomedical subjects

J L Luque

Publications and source records attributed to J L Luque.

10 recordsLinked to original sources

PubMed2001

Community ecology of the metazoan parasites of white croaker, Micropogonias furnieri (Osteichthyes: Sciaenidae), from the coastal zone of the State of Rio de Janeiro, Brazil.

One hundred specimens of white croakers, Micropogonias furnieri (Desmarest 1823) (Osteichthyes: Sciaenidae) collected from Pedra de Guaratiba (23 degrees 01'S, 43 degrees 38'W), State of Rio de Janeiro, Brazil, from September 1997 to August 1999, were necropsied to study their parasites. The majority of the fish (95%) were parasitized by metazoan. Twenty-eight species of parasites were collected. The nematodes were the 40.5% of the total number of parasites specimens collected. Dichelyne elongatus was the most dominant species. Lobatostoma ringens, Pterinotrematoides mexicanum, Corynosoma australe, D. elongatus, and Caligus haemulonis showed a positive correlation between the host's total length and parasite prevalence and abundance. The monogenean P. mexicanum had differences in the prevalence and abundance in relation to sex of the host. The mean diversity in the infracommunities of M. furnieri was H=0.499+/-0.411, with correlation with the host's total length and without differences in relation to sex of the host. One pair of ectoparasites showed positive covariation, and two pairs of endoparasites showed positive association and covariation between their prevalences and abundances, respectively. Negative association or covariations were not found. The dominance of endoparasites in the croakers parasite infracommunities reinforced the differences found in sciaenids from the South American Pacific Ocean, in which the ectoparasites are dominant.

Animals↗

PubMed2000

Does the type of judgement required modulate cue competition?

According to the comparator process hypothesis (Matute, Arcediano, & Miller, 1996), cue competition in the learning of between-events relationships arises if the judgement required involves a comparison between the probability of the outcome given the target cue and the probability of the outcome given the competing cue. Alternatively, other associative accounts (the Rescorla-Wagner model: Rescorla & Wagner, 1972) conceive cue competition as a learning deficit affecting the target cue-outcome association. Consequently, the comparator process hypothesis predicts that cue competition occurs in inference judgements but not in contiguity ones, for only the first type of judgement implicitly involves such a comparison. On the other hand, the Rescorla-Wagner model predicts cue competition in both inference and contiguity judgements, because it establishes no relevant role for the type of judgement in producing cue competition. In Experiments 1 and 2 we manipulated the relative validity of cues and the type of question (inference vs. contiguity) in a predictive learning task. In both experiments we found a cue competition effect, but no interaction between the relative validity of cues and the type of question, suggesting that the Rescorla-Wagner theory suffices to explain cue competition.

Adult↗

PubMed1999

Metazoan parasite infracommunities of Menticirrhus (Teleostei: Sciaenidae): an amphi-oceanic approximation.

Metazoan infracommunities of Menticirrhus ophicephalus from the south Pacific Ocean and M. americanus from the south Atlantic Ocean were analyzed and compared. The metazoan parasite infracommunities of M. ophicephalus showed higher values of total number of parasite individuals/host and parasite species richness than that of M americanus, but M. americanus showed higher values of parasite species diversity. The infracommunities of ectoparasites showed higher values of total number of parasite individuals/host, richness, and frequency of dominance in M. ophicephalus; in contrast, endoparasites showed higher values of these infracommunity descriptors in M. americanus. Ecological analysis of the marine fish parasite infracommunities using the total number of components (ecto- and endoparasites) could hide some patterns of the community structure; thus, a separate analysis of only ecto- or endoparasites is recommended. Additional studies monitoring the influence of the "upwelling ecosystem" and the El Niño-Southern oscillation event on the fish parasite communities are necessary to determine the real influence of these ecological disturbances on the structure of fish parasite communities in South America.

Animals↗

PubMed1997

Community ecology of the metazoan parasites of grey mullets, Mugil platanus (Osteichthyes: Mugilidae) from the littoral of the state of Rio de Janeiro, Brazil.

One hundred and fifty specimens of grey mullets, Mugil platanus Günther, collected from the littoral of the State of Rio de Janeiro, Brazil, between June 1984 to August 1988, were necropsied to study their infracommunities of metazoan parasites. Twenty-five species of metazoan parasites were collected. One hundred and forty-nine (99.3%) fishes were parasitized by one or more metazoan species. According to their importance values, 13 species were considered dominant, 7 species codominant and 2 species subordinate (digeneans were the majority of the total number of parasite specimens collected, with 63.7%). The presence of larval stages of digeneans and cestodes suggest that M. platanus is at an intermediate level in the marine trophic web. The Simpson index for all parasite species was low (0.059) indicating lack of dominance by a particular species in the parasite community. The parasites of M. platanus showed a typical overdispersed pattern of distribution. The capture localities of the hosts were consolidated into 3 groups and its parasite communities showed high qualitative and quantitative similarity, with high values for the Sorenson similarity coefficient and Percent similarity coefficient. Six species had a positive correlation between the host's total body length and parasite intensity, while three species had a negative correlation. Four species had a positive correlation between the host's total body length and parasite prevalence and one species had negative correlation. Five parasite species had differences in prevalence and intensity in relation to sex of host, but these differences were confounded with the total length of male and female fishes. The mean diversity in the infracommunities of M. platanus was H' = 0.936 +/- 0.477, without correlation with the host's total length and without significant difference between male and female fishes. In the ectoparasites, the infracommunities showed overall positive association, 6 pairs of copepod species had a significant positive association. One pair of species showed a negative covariation between parasite intensities. Infracommunities of endoparasites also showed overall positive association, and four species pairs of digeneans had a significant positive association. Only one had a negative association. The specialist components with low prevalence values predominated in the parasite community, which, based on these factors, was considered closer to the isolationist type.

Animals↗

PubMed1996

Using computer systems to enhance case management.

This article describes how an on-line computer system can enhance case management by improving communication within internal departments and adding consistency and objectivity to the referral process. At PacifiCare, the computer system has supported case management's efforts to provide members with cost-effective medical care and has improved satisfaction with the health plan.

California↗

PubMed1996

[Transversal partitioning and interspecific associations in communities of ectoparasitic metazoans in marine sciaenid fishes from Peru].

During 1987 and 1988 marine sciaenid fishes from the central Peruvian coast were examined: 237 Menticirrhus ophicephalus, 124 Paralonchurus peruanus, 249 Sciaena deliciosa, 50 Sciaena fasciata and 311 Stellifer minor. Thirty metazoan ectoparasites were identified, 18 helminths and 12 crustaceans. Paralonchurus peruanus was the species with higher number of ectoparasite species (11). The communities of ectoparasites were dominated by diplectanid monogeneans. The following showed preference by some site of infestation in their transversal partitioning: Rhamnocercoides menticirrhi, Rhamnocercus spp., Diplectanum sp., Pseudohaliotrema paralonchuri, Pedocotyle annakohni, P. bravoi, Caligus callaoensis and Lernanthropus huamani. With the exception of P. peruanus, these fishes showed an overall positive association in their ectoparasite communities. Menticirrhus ophicephalus and S. deliciosa had the most pairs of associated and covariated species. Paralonchurus peruanus and S. minor showed no interspecific associations. Negative interspecific association and covariation were not determined. The pair R. menticirrhi-L. huamani (in M. ophicephalus) had the highest association degree. These results suggest an absence of competitive interspecific processes.

Animals↗

PubMed1996

Comparative analysis of the metazoan parasite communities of leatherjackets, Oligoplites palometa, O. saurus, and O. saliens (Osteichthyes:Carangidae) from Sepetiba Bay, Rio de Janeiro, Brazil.

One hundred and fifty-seven specimens of leatherjackets, 84 specimens of Oligoplites palometa (Cuvier), 37 specimens of O. saurus (Bloch & Schneider), and 36 specimens of O. saliens (Bloch) captured at the Sepetiba Bay, State of Rio de Janeiro, between March of 1991 and November of 1992, were necropsied to study their communities of metazoan parasites. All fishes studied were parasitized by one or more metazoan species. Eighteen parasite species were found in O. palometa and 13 parasite species were found in O. saurus and O. saliens, respectively. The digeneans were the majority of the parasite specimens collected, with 90.3%, 82.2%, and 87.7% in O. palometa, O. saurus, and O. saliens, respectively. The Simpson index was lower than 0.25 for the 3 host species, showing an absence of concentration for dominance. The similarity coefficients among the parasite communities of the 3 fish species was above 66%. The parasites of the 3 host species showed typical overdispersed pattern of distribution. Four cases of positive correlation between host's total length and prevalence and parasite intensity were found. The majority of the species did not show influence of host sex. The 3 host species had similar parasite diversity, which was not correlated with the host's total body length and there was no significant difference between male and female hosts. Oligoplites palometa and O. saurus each had one pair of ectoparasite species sharing a positive association and with a positive correlation between their intensities. No pairs of associated species were found in O. saliens. Parasites were found along the entire extension of the gastrointestinal tract of the 3 host species. The parasite communities of O. palometa, O. saurus, and O. saliens are defined as isolationists because there are few evidences of interspecific association or covariation. The presence of larval stages of cestodes and nematodes suggests that the three species of Oligoplites are at an intermediate level in the marine trophic web.

Animals↗

PubMedDate not supplied

Pseudohaliotrema paralonchuri sp. n. (Monogenoidea: Dactylogyridae), parasitic on Paralonchurus peruanus (Steindachner) (Teleostei: Sciaenidae) from the Peruvian coast.

Pseudohaliotrema paralonchuri sp. n., parasitic on the sciaenid fish Paralonchurus peruanus (Steindachner) from the Peruvian central coast, is described, illustrated and compared with related species of the genus. P. paralonchuri differs from other Pseudohaliotrema by the characteristics of the cirrus, accessory piece, anchors and bars. This is the first record of Pseudohaliotrema from the South American Pacific Ocean.

Animals↗

PubMedDate not supplied

The metazoan parasites of Stellifer minor (Tschudi, 1844): an ecological approach.

A quantitative and qualitative analysis of the parasite fauna of the sciaenid Stellifer minor (Tschudi) from Chorrillos, Perú, was made. Some characteristics of the infectious processes, in terms of intensity and prevalence of infection, as a function of host sex and size, are given. Moreover, comments on the characteristics of the parasite fauna, related with host role in the marine food webs are included. The parasite fauna of Stellifer minor taken off Chorrillos, Perú, include the monogeneans Pedocotyle annakohni, Pedocotyle bravoi, Rhamnocercus sp. and Cynoscionicola sp., the digenean Helicometra fasciata, the adult acantocephalan Rhadinorhynchus sp. and the larval Corynosoma sp., the nematode Procamallanus sp., the copepods Caligus quadratus, Clavellotis dilatata and Bomolochus peruensis and one unidentified isopod of the family Cymothoidae. A distinctive characteristic of the parasite fauna (Metazoa) of S. minor is the almost absence of larval forms.

Animals↗

PubMedDate not supplied

Redescription of Rhamnocercus stichospinus Seamster and Monaco, 1956 (Monogenea: Diplectanidae), parasitic on Menticirrhus americanus (Osteichthyes: Sciaenidae) from the coastal zone of the State of Rio de Janeiro, Brazil.

Rhamnocercus stichospinus Seamster and Monaco, 1956 (Diplectanidae) parasitic on the sciaenid fish Menticirrhus americanus from the coastal zone of the State of Rio de Janeiro, is redescribed and recorded for the first time in the South American Atlantic Ocean. The generic diagnosis of Rhamnocercus is emended to accommodate the presence of confluent intestinal ceca in R. stichospinus.

Animals↗