Diel vertical migration of predators (planktivorous fish larvae) and prey (zooplankton) in a tropical lagoon

ABSTRACT Based on the hypothesis that diel vertical migration (DVM) is a mechanism of predator avoidance, the objective of the present study was to test for the occurrence of DVM in planktivorous fish larvae of Hypophthalmus edentatus (Spix, 1829) (Siluriformes, Pimelodidae) and Plagioscion squamosissimus (Heckel, 1840) (Perciformes, Sciaenidae), and zooplankton (rotifers, cladocerans and copepods) in an isolated tropical lagoon in the floodplain of the Upper Paraná River, Brazil (region of Parque Nacional de Ilha Grande). We investigated spatial overlap between predators (planktivorous fish larvae) and prey (zooplankton), and tested which physical and chemical variables of the water are related to the DVM of the studied communities. We performed nocturnal (8:00 pm and 4:00 am) and diurnal sampling (8:00 am and 4:00 pm) in the limnetic region of the lagoon for six consecutive months, from October 2010 to March 2011, which comprises the reproductive period of the fish species analyzed. During the day the larvae tried to remain aggregated in the bottom of the lagoon, whereas at night they tried to disperse in the water column. Especially for cladocerans, the diel vertical migration is an important behavior to avoid predation larvae of H. edentatus and P. squamosissimus once decreased spatial overlap between secured and its potential predators, which corroborates the hypothesis that DVM is a mechanism of predator avoidance. Although significant correlations were observed between the abiotic factors and WMD of microcrustaceans at certain times of day, the effect of predation of fish larvae on zooplankton showed more important in this environment, because the small depth and isolation not allow great variation of abiotic factors seasonally and between strata the lagoon.

Tropical varieties for non-archimedean analytic spaces

"Vegeu el resum a l'inici del document del fitxer adjunt."

Parametric analysis of different compact tension specimens for fracture toughness characterisation in woven composite materials

Estudi elaborat a partir d’una estada a l’ Imperial College London, entre juliol i novembre de 2006. En aquest treball s’ha investigat la geometria més apropiada per a la caracterització de la tenacitat a fractura intralaminar de materials compòsits laminats amb teixit. L’objectiu és assegurar la propagació de l’esquerda sense que la proveta falli abans per cap altre mecanisme de dany per tal de permetre la caracterització experimental de la tenacitat a fractura intralaminar de materials compòsits laminats amb teixit. Amb aquesta fi, s’ha dut a terme l’anàlisi paramètrica de diferents tipus de provetes mitjançant el mètode dels elements finits (FE) combinat amb la virtual crack closure technique (VCCT). Les geometries de les provetes analitzades corresponen a la proveta de l’assaig compact tension (CT) i diferents variacions com la extended compact tension (ECT), la proveta widened compact tension (WCT), tapered compact tension (TCT) i doubly-tapered compact tension (2TCT). Com a resultat d’aquestes anàlisis s’han derivat diferents conclusions per obtenir la geometria de proveta més apropiada per a la caracterització de la tenacitat a fractura intralaminar de materials compòsits laminats amb teixit. A més, també s’han dut a terme una sèrie d’assaigs experimentals per tal de validar els resultats de les anàlisis paramètriques. La concordança trobada entre els resultats numèrics i experimentals és bona tot i la presència d’efectes no previstos durant els assaigs experimentals.

Production and carcass quality of ten beef cattle breeds of the southwest of Europe

A sample of about 70 young bulls of each of ten beef cattle breeds reared in their typical production systems has been studied regarding growth and carcass quality traits. Breeds included were Asturiana de los Valles (AV), Asturiana de la Montaña (AM), Avileña-Negra Ibérica (A-NI), Bruna dels Pirineus (BP), Morucha (Mo), Pirenaica (Pi) and Retinta (Re) from Spain, and Aubrac (Au), Gasconne (Ga) and Salers (Sal) from France. There existed large differences between breeds and also within breeds. AV and Pi were the breeds with more muscle and less fat, whereas A-NI, Mo and Re were in the opposite side. BP and AM occupied an intermediate position. This allows to classify the Spanish breeds in three groups: AV and Pi would belong to the group of late maturity, A-NI, Mo and Re, would be early maturing breeds, whereas BP and AM, despite the small size of the last, will be of intermediate maturity. In the French populations, Au was the breed with the highest carcass weight and Ga exhibited the lowest. Sal occupied an intermediate position, showing the longer and thinner thigh. In a wide range of carcass weight, the general relationships among carcass traits have been confirmed. Animals with the better conformation were also the leaner and longer carcasses tended to be lowly associated with a poorer conformation and fatter carcasses. Bone content was clearly opposed to carcass conformation and muscle content and was associated with longer carcasses

Meat quality of ten cattle breeds of the Southwest of Europe

A sample of about 70 young bulls of each of ten beef cattle breeds reared in their typical production systems has been characterised with respect to meat quality traits. Breeds included were Asturiana de los Valles, Asturiana de la Montaña, Avileña-Negra Ibérica, Bruna dels Pirineus, Morucha, Pirenaica and Retinta from Spain, and Aubrac, Gasconne and Salers from France. As was previously showed regarding carcass traits, there exist large differences both between and within breed – systems. In general, rustic breeds tended to present darker and redder meats with higher haematin contents, whereas less precocious and more specialised breeds showed brighter meats with bigger water losses. Protein content was similar, whereas intramuscular fat presented the larger variations both between and within breeds. ICDH content was higher in the more rustic breeds, showing the predominantly oxidative character of their fibres. Texture measurements showed in general large within breed-system variations, the differences between breeds being less evident. Within breed-system, daily gain weight was positively associated with brighter and tender meats. In the range studied, increasing slaughter weight within breed did not have influence on meat quality. Conformation was related to lower water holding capacity and less dry matter and intramuscular fat, as well as to a lower haematin content giving brighter meats. The increase in fatness scores was related to an augment of toughness in meat specialised breeds, although in Avileña-Negra Ibérica breed fatness carcasses were related to more tender meats. Redness parameter a* was positively related to fatter animals and opposed to conformation, the opposite being true for the L* (lightness) parameter. There was a small trend of fatter carcasses to be related to oxidative fibres, whereas the muscular fibres of the more conformed carcasses were more glycolytic. Texture measurements maximum load, maximum stress and toughness were very closely related. Shear force was opposed to tenderness. Losses at cooking were opposed to juiciness, but only in the Spanish breeds. No consistent trends regarding relationships between carcass characteristics and tenderness could be observed. Overall acceptability was primarily related with tenderness and flavour, and later on juiciness.

In vitro cell activating properties of the composite ribosomal vaccine D53

D53 (RibomuntyR) is a composite vaccine made of immunogenic ribosomes from 4 bacterial species (Klebsiella pneumoniae, Haemophilus influenzae, Streptococcus pyogenes and Streptococcus pneumoniae) associated with a membrane proteoglycan from a non encapsulated strain of Klebsiella pneumoniae. D53 is a potent inducer of interleukin-1 production by mouse BALB/c spleen cells as shown by the C3H/HeJ thymocyte co-stimulation assay. Furthermore D53 triggers DNA synthesis by mouse spleen cells and induces the maturation of B lymphocytes into immunoglobulin secreting cells. Polyclonal B cell activation by D53 was readily achieved in the C3H/HeJ strain which is deficient in its response to E. coli lipopolysaccharide. The proliferative response to D53 was abrogated by removal of B cells from the spleen cell suspension, but it was not altered after depletion of T cells or adherent cells. D53 induced polyclonal B cell activation of spleen cells from athymic nude mice and from CBA/N mice. Each component of D53 induced polyclona B cell activation except ribosomes from Streptococcus pneumoniae. Each triggered Interleukin-1 synthesis except ribosomes from Klebsiella penumoniae. These in vitro properties may account for some of the in vivo immunostimulating properties of this composite vaccine.

A new species of culex (Melanoconion) from atlantic tropical system of Souther Brazil (Diptera: Culicidae)

The male adult of Culex (Melanoconion) anoplicitus, a new species from Southern Tropical Atlantic System of Brazil, South America, is described and illustrated. Identification may be made by characteristic morphological aspects of genitalia which are peculiar to this species.

Toxicological and toxicogenetic effects of plants used in popular medicine and in cattle food

Toxicological and toxicogenetic effects of aqueous (tea) and hexanica fruit extract of Indigofera suffruticosa Mill, and hydroalcoholic root extract od Solanum agrarium Stendt. Were evaluated in Balb C male mice intraperitoneally exposed. A hepatotoxic effect was observed just for animals treated with aqueous fruit extract of I. suffruticosa. In relation to the toxicogenetic effect, just the group trreated with 12.5% of toxic dose of aqueous fruit extract of I. suffruticosa showed a statistically significant increase in the frequency of cells with chromosome aberrations (cytogenetic effect), although a slight increase was also observed for the highest dose (25% of LF50_ of hydroalcoholic root extract of S. agrarium. The results obtanied show that before S. agrarium is used as medicine and before the wide use of I. suffruticosa in cattle food, careful evaluation must be done.

Estimating patterns of leaf herbivory along an altitudinal transect in NE Queensland rainforests: might global warming increase leaf herbivory in tropical rainforests?

Climate change has been taking place at unprecedented rates over the past decades. These fast alterations caused by human activities are leading to a global warming of the planet. Warmer temperatures are going to have important effects on vegetation and especially on tropical forests. Insects as well will be affected by climate change. This study tested the hypothesis that higher temperatures lead to a higher insect pressure on vegetation. Visual estimations of leaf damage were recorded and used to assess the extent of herbivory in nine 0.1ha plots along an altitudinal gradient, and therefore a temperature gradient. These estimations were made at both a community level and a species level, on 2 target species. Leaf toughness tests were performed on samples from the target species from each plot. Results showed a strong evidence of increasing insect damage along increasing temperature, with no significant effect from the leaf toughness.

Cotylophoron travassosi sp.n. (Trematoda - Paramphistomidae) from cattle

A new species of the genus Cotylophoron (Trematoda - Paramphistomidae) - Cotylophoron travassosi sp. n. - is described. The measurements of the worm and its structures are compared with the valid known species.

Preliminary investigations on transmission and life cycle of the ear mites of the genus Raillietia trouessart (Acari: Gamasida) parasites of cattle

The life cycle of ear mites of the genus Raillietia Trouessart consists of egg, larva, proto-and deutonymph and adult. The proto-and deutonymph are free living, non feeding instars. The teneral adult is the transfer stage. The minimum period required for completion of the life cycle is approximately eight days.

Prevalence and control of Babesiosis in the Americas

This review presents up-to-date information on the distribution and control measures of babesiosis in Latin America. Bovine babesiosis caused by Babesia bovis and B. bigemia will be emphasized. The disease is endemic is most countries and poses a serious economic burdenon livestock production in the region (U.S.$1365 million/year, FAO, 1989). Of the estimated 250 million cattle in Central and South America, approximately 175 million (70%) are in tick-infested regions. Humid, tropical and subtropical areas favor development of the main vector, the one-host tick Boophilus microplus. In many regions bovine babesiosis is enzootically stable as consequence of a balanced host-parasite relationship. However, Latin America offers a wide range of epidemiologica conditions that are influenced by variations from tropical to cool climates and by susceptible purebred cattle that are regularly imported to upgrade local stocks. The control measures employed in most countries for babesiosis esentially rely on chemotherapy, use of acaricides for B. microplus, and to a lesser degree, on immunization methods. In general, these measures are expensive, time consuming, and in many cases, provide limited success. Finally, the zoonotic potential ob babesiosis will be addressd, with special emphasis on the situation in the United States. Even though bovine babesiosis has long been eradicated from the U.S.A., human babesiosis in endemic in the northeastern region of the country.

The level of infestation with the vector of cattle babesiosis in Argentina

Studies were carried out to determine the differential aptitude to sustain the only vector of cattle babesiosis in Argentina, the tick Boophilus microplus, throughout the infested region of this country. Tick counts on Bos taurus cattle were used as the main criterion to classify favourable (F), intermediate (I) and unfavourable (U) areas for its development. The geographical limits of each area set up using data of non-parasitic tick stages, temperature, water balance and map recognition of flooded and unflooded zones. The F area contained 16.5 x 10 (elevado a sexta potência) ha with a cattle population of 6 x 10 (elevado a sexta potência); the I and U areas had 25 x 10 (elevado a sexta potência ha with 2.7 x 10 (elevado a sexta potência) cattle and 198 x 10 (elevado a sexta potência) with population of 2.4 x 10(elevado a sexta potência) cattle, respectively. Research on the relationship amongst Babesia-Boophilus-cattle is needed in the F area for tick development which coincides with the best region for cattle breeding.