311 resultados para Ontogenetic


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To design strategies for the conservation and use of genetic resources of tree species such as jaboticaba tree, it is essential to make the characterization. In southwestern Paraná region, there are several forest fragments containing native jaboticaba tree (Plinia cauliflora), whose materials have broad potential for commercial orchards or breeding programs. As is the potential genetic diversity of a population to produce different genotypes, it would be able to start in such a characterization one of these fragments. The aim was to characterize fruits of jaboticaba tree (P. caulifora) of forest fragment kept in Clevelândia - PR for the presence of phenotypic variability, seeking to identify those superiors named for future selection as farming or male parent, as well as estimate genetic divergence between them, as a complementary tool for this purpose. Also, verify the regeneration and spatial distribution of the species. For the study was defined portion of a hectare (10.000 m²), with all individuals identified, mapped, with local coordinate system, and measured height and diameter. Fruits were characterized by sensory and biochemical characteristics in two years, 70 genotypes at 2013 and 56 at 2014, and of these 33 genotypes in both years. As a pre-selection criteria was adopted the choice of 20% of the genotypes that showed the highest frequency of superiority in the evaluated characteristics of the fruit. Genetic divergence among 33 genotypes per year was analyzed. The distribution pattern and spatial association was evaluated by Ripley's K function. It was classified for the first time the following ontogenetic stages of jaboticaba tree, by plant height, seedling (from 0.01 to 0.99 m), juvenile (1.0 to 4.99 m), immature (> 5.0 m, non-reproductive), adult (reproductive). It was also have been describe for the first time the naturally occurring juxtaposed seedlings, indicating polyembryony. The number of regenerating identified in the population (seedlings: n = 2163; juveniles: n = 330; immature: n = 59) was much larger than the number of adults (n = 132). The species showed reverse J-shaped size structure standard, with high concentration of regenerating. The regeneration distribution occurs in aggregate pattern and there is seedling-adult dependence, due seed dispersal and seedling emergence closest to mothers. The jaboticaba tree regeneration is sufficient to maintain the species for long term in this population, which should serve as reference to regeneration success for other studies of this important fruiting species from Ombrofile Mixed Forests. Has been pre-selected the jaboticaba trees 7, 42, 43, 47, 54, 91, 97, 104, 105, 118, 134, 153, 154, 157, 163, 169, 177, 186, 212, J7-01 and J7- 02, and 16 and 194 the ones that can now be selected by the superior characteristics of both cycles. It was recommended to carry out hybridization between genotypes 79 and 119, and 96 to 148. The quality of fruit analyzed showed potential for use as a dual purpose serving both in natura market or processing.

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The species Dasyatis marianae inhabits coastal areas associated with coral reefs, considered endemic to the northeast of Brazil, occurring from the State of Maranhão to the south of Bahia. Specimens of this species are commonly sighted by divers and fishermen in the area of Maracajaú reefs, a complex reef that is part of the Environmental Protection Area of Coral Reefs (EPACR), which was developed in this study about the ecology and biology of the D. marianae, in order to characterize aspects of population structure in the area of the reef complex of Parracho de Maracajaú. We analyzed 120 specimens caught by artisanal fishing site of the size, weight, sex, stage of maturity and stomach contents. Most subjects were adult males (1.7:1) and was more abundant for rays with lengths between 25 and 29cm of LD, where females reach larger sizes, a feature common to other rays. The largest specimens were captured in the area of seagrass, which is preferred for the species. The distribution of species in the area showed an ontogenetic and sexual segregation, where the youthful occur near the beach, which is a likely area for nursery and growth of the adult females prevail in the seagrass, which apparently has a high prey availability, and Adult males are more distant, a higher proportion occurring in outlying areas, suggesting a habit more exploratory than the females. The evaluation of the reproductive system indicated 3 reproductive cycles per year, one young per pregnancy, and showed that the mature males were smaller than females. The cubs of D. marianae size at birth 12 to 15cm LD. As for diet, the species was characterized as carnivorous crustacean specialist. The performance of visual censuses in different localities allowed to evaluate the density of D. marianae in different environments of the complex. The species occurs in greater numbers in seagrass, environment very important for the conservation of the species. 100 individuals of D. marianae marked in reef complex area enrolled in a recapture rate of 3%. Some behavioral aspects were evaluated, as diurnal pattern of activity, interaction with cleaning and fish Pomacanthus paru followers as Lutjanus analis and Carangoides bartholomaei. Overall, much of the information obtained should be used for management of the species

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W artykule przedstawiono problematykę śmierci osobniczej (mózgowej) jako przesłanki dopuszczalności przeszczepu ex mortuo. W pierwszej kolejności zostały opisane podstawowe zagadnienia dotyczące pojęcia transplantacji oraz jej rodzajów występujących w piśmiennictwie medycznym. Dalej poruszono tematykę śmierci i jej rodzajów w kontekście transplantacji, podkreślono również występującą w doktrynie różnicę utożsamiania śmierci klinicznej ze śmiercią pozorną, a także przedstawiono występujący w literaturze sztuczny podział śmierci ze względu na narządy, tj. mózg, płuca i serce. Głównym punktem pracy jest zagadnienie śmierci mózgowej (osobniczej). Wskazano wątpliwości natury prawnej, medycznej i społecznej odnośnie do tej przesłanki. Wskazano na metodykę pracy przy ustaleniu śmierci mózgowej. Zwrócono uwagę na fakt zmiany definicji na gruncie obowiązującej ustawy transplantacyjnej. W dalszej kolejności zostało poruszone zagadnienie śmierci wskutek nieodwracalnego zatrzymania krążenia. W podsumowaniu zebrano w sposób ścisły wątki omawiane przez całą pracę i wspominano o innych przesłankach dopuszczalności przeszczepu ex mortuo.

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European sea bass, Dicentrarchus labrax, is a highly valuable species in Europe, both for aquaculture in the Mediterranean Sea and for commercial and recreational fisheries in the North East Atlantic Ocean. Subjected to increasing fishing pressure, the wild population has recently experienced significant recruitment fluctuation as well as a northward extension of its distribution area in the North Sea. While the nature of the ecological and/or physiological processes involved remains unresolved, ontogenetic habitat shifts and adult site fidelity could increase the species’ vulnerability to climate change and overfishing. As managers look for expert information to propose management scenarios leading to sustainable exploitation, exploratory modelling appears to be a cost-efficient approach to enhance the understanding of recruitment dynamics and the spatio-temporal scales over which fish populations function. A conceptual modelling framework and its specific data requirements are discussed to tackle some sound ecological questions regarding this species. We consequently provide an updated review of current knowledge on bass population structure, biology and ecology. This paper will hence be particularly valuable to develop spatially-explicit models of European sea bass dynamics under environmental and anthropogenic forcing. Knowledge gaps requiring further research efforts are also reported.

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Otoliths are calcified structures located in Osteichthyes’ inner ear that are involved in audition and balance. Their morphology is used as an indicator of various ecological processes or properties. This application requires identifying the endogenous and exogenous factors that act simultaneously as sources of shape variation. This thesis aims at detecting and quantifying the relative contributions of directional asymmetry and diet to otolith shape variation at the intra-population level. Directional asymmetry between left and right otoliths was found in flat-fishes, the blind-side otolith being always longer and larger, whereas it was negligible in round-fishes. However, asymmetry amplitude never exceeded 18 %, which suggests evolutionary canalization of otolith shape symmetry. A correlation between global diet and otolith was detected in 4 species studied in situ. Diet composition contributed more than food amount to morphological variation and affected otolith shape both globally and locally. An experimental study on sea bass (Dicentrarchus larbrax) showed that diet composition in terms of essential polyunsaturated fatty acids at larval stage affects otolith morphogenesis during juvenile stage without impacting on individuals’ somatic growth. This result suggests a direct effect of diet on otolith shape and not an indirect one through the somatic-otolith growth relationship. This effect disappeared at later stages, morphogenetic trajectories converging back to a similar shape, which suggests ontogenetic canalization of otolith shape.

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Vocal differentiation is widely documented in birds and mammals but has been poorly investigated in other vertebrates, including fish, which represent the oldest extant vertebrate group. Neural circuitry controlling vocal behaviour is thought to have evolved from conserved brain areas that originated in fish, making this taxon key to understanding the evolution and development of the vertebrate vocal-auditory systems. This study examines ontogenetic changes in the vocal repertoire and whether vocal differentiation parallels auditory development in the Lusitanian toadfish Halobatrachus didactylus (Batrachoididae). This species exhibits a complex acoustic repertoire and is vocally active during early development. Vocalisations were recorded during social interactions for four size groups (fry: <2 cm; small juveniles: 2-4 cm; large juveniles: 5-7 cm; adults >25 cm, standard length). Auditory sensitivity of juveniles and adults was determined based on evoked potentials recorded from the inner ear saccule in response to pure tones of 75-945 Hz. We show an ontogenetic increment in the vocal repertoire from simple broadband-pulsed 'grunts' that later differentiate into four distinct vocalisations, including low-frequency amplitude-modulated 'boatwhistles'. Whereas fry emitted mostly single grunts, large juveniles exhibited vocalisations similar to the adult vocal repertoire. Saccular sensitivity revealed a three-fold enhancement at most frequencies tested from small to large juveniles; however, large juveniles were similar in sensitivity to adults. We provide the first clear evidence of ontogenetic vocal differentiation in fish, as previously described for higher vertebrates. Our results suggest a parallel development between the vocal motor pathway and the peripheral auditory system for acoustic social communication in fish.

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Size-related and seasonal evaluation of the dietary composition of fat snook (Centropomus parallelus Poey 1860) in the upper sector of an estuary of the southeastern coast of Brazil were carried out based on stomach analyses of specimens ranging from 40 to 170 mm standard length. Results reveal that C. parallelus is a carnivorous species feeding mainly on benthic crustaceans. Relatively high stomach replenishment suggests that this environment is an important feeding ground for fat snook juveniles. Multivariate analyses indicated that predator size effect is significantly more important than seasonal variation in determining dietary composition. Predator length was associated with increased consumption of palaemonid shrimps (Macrobrachium spp.) and grapsid crabs, and decreased foraging on tanaids (Kalliapseudes schubarti), thus showing a preference shift from smaller to larger prey. Predator length was also positively associated with an increase in the stomach repletion index. Additionally, allometric growth of both gape and head were consistently correlated with this ontogenetic dietary transition, suggesting that such changes might be related to an individual's ability to capture and consume larger, more elusive prey. The digestive tube is short and grows isometrically, which is in accordance with the carnivorous habit of this estuarine fish and its maintenance through ontogeny.

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The species Dasyatis marianae inhabits coastal areas associated with coral reefs, considered endemic to the northeast of Brazil, occurring from the State of Maranhão to the south of Bahia. Specimens of this species are commonly sighted by divers and fishermen in the area of Maracajaú reefs, a complex reef that is part of the Environmental Protection Area of Coral Reefs (EPACR), which was developed in this study about the ecology and biology of the D. marianae, in order to characterize aspects of population structure in the area of the reef complex of Parracho de Maracajaú. We analyzed 120 specimens caught by artisanal fishing site of the size, weight, sex, stage of maturity and stomach contents. Most subjects were adult males (1.7:1) and was more abundant for rays with lengths between 25 and 29cm of LD, where females reach larger sizes, a feature common to other rays. The largest specimens were captured in the area of seagrass, which is preferred for the species. The distribution of species in the area showed an ontogenetic and sexual segregation, where the youthful occur near the beach, which is a likely area for nursery and growth of the adult females prevail in the seagrass, which apparently has a high prey availability, and Adult males are more distant, a higher proportion occurring in outlying areas, suggesting a habit more exploratory than the females. The evaluation of the reproductive system indicated 3 reproductive cycles per year, one young per pregnancy, and showed that the mature males were smaller than females. The cubs of D. marianae size at birth 12 to 15cm LD. As for diet, the species was characterized as carnivorous crustacean specialist. The performance of visual censuses in different localities allowed to evaluate the density of D. marianae in different environments of the complex. The species occurs in greater numbers in seagrass, environment very important for the conservation of the species. 100 individuals of D. marianae marked in reef complex area enrolled in a recapture rate of 3%. Some behavioral aspects were evaluated, as diurnal pattern of activity, interaction with cleaning and fish Pomacanthus paru followers as Lutjanus analis and Carangoides bartholomaei. Overall, much of the information obtained should be used for management of the species

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Tese (doutorado)—Universidade de Brasília, Faculdade de Ciência da Informação, Programa de Pós-Graduação em Ciência da Informação, 2016.

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In long-lived species with slow maturation, prebreeders often represent a large percentage of the individuals alive at any moment, but their ecology is still understudied. Recent studies have found prebreeding seabirds to differ in their isotopic (and trophic) niche from adult breeders attending the same nesting colonies. These differences have been hypothesized to be linked to the less-developed foraging performance of younger and less-experienced immatures or perhaps to their inferior competitive abilities. Such differences from adults would wane as individuals mature (“the progressive ontogenetic shift hypothesis”) and could underpin the prolonged breeding deferral until adulthood displayed by those species. This study documents a marked difference in the nitrogen and carbon isotopic ratios measured in the whole blood of immatures and breeders in 2 pelagic seabird species (Cory’s shearwaters, Calonectris borealis, and black-browed albatrosses, Thalassarche melanophris) nesting in contrasting environments. However, blood isotopic values did not present a relationship with prebreeder age, suggesting no gradual ontogenetic shift from an immature toward an adult isotopic niche. Furthermore, isotopic signatures of sabbatical adults could not be separated from those of immatures attending the same colonies, but were clearly segregated from adult breeders. These results suggest that isotopic differentiation between immatures and breeders is mainly linked to a factor unrelated to previous experience and hence probably unrelated to a hypothetical gradual improvement of foraging competence or competitive abilities. Any ecological differentiation between breeders and nonbreeders is more likely related to the severity of the central-place foraging constraints and to the energetic requirements of reproduction (“the reproductive constraint hypothesis”).