Variability and significance of parietal and ventral scales in the marine snakes of the genus Lapemis (Serpentes, Hydrophiidae), with comments on the occurance of spiny scales in the genus / Paul Gritis, Harold K. Voris.

n.s. no.56(1990)

The importance of catfish burrows in maintaining fish populations of tropical freshwater streams in western Ecuador / Garrett S. Glodek.

v.73:no.1(1978)

Assessing the performance of macroinvertebrate metrics in the Challhuaco-Ñireco System (Northern Patagonia, Argentina)

ABSTRACT Seven sites were examined in the Challhuaco-Ñireco system, located in the reserve of the Nahuel Huapi National Park, however part of the catchment is urbanized, being San Carlos de Bariloche (150,000 inhabitants) placed in the lower part of the basin. Physico-chemical variables were measured and benthic macroinvertebrates were collected during three consecutive years at seven sites from the headwater to the river outlet. Sites near the source of the river were characterised by Plecoptera, Ephemeroptera, Trichoptera and Diptera, whereas sites close to the river mouth were dominated by Diptera, Oligochaeta and Mollusca. Regarding functional feeding groups, collector-gatherers were dominant at all sites and this pattern was consistent among years. Ordination Analysis (RDA) revealed that species assemblages distribution responded to the climatic and topographic gradient (temperature and elevation), but also were associated with variables related to human impact (conductivity, nitrate and phosphate contents). Species assemblages at headwaters were mostly represented by sensitive insects, whereas tolerant taxa such as Tubificidae, Lumbriculidae, Chironomidae and crustacean Aegla sp. were dominant at urbanised sites. Regarding macroinvertebrate metrics employed, total richness, EPT taxa, Shannon diversity index and Biotic Monitoring Patagonian Stream index resulted fairly consistent and evidenced different levels of disturbances at the stream, meaning that this measures are suitable for evaluation of the status of Patagonian mountain streams.

The microscope and histology for the use of laboratory students in the anatomical department of Cornell University. by Simon Henry Gage.

3rd ed

The behavior of money velocity in low and high inflation countries

This paper presents a general equilibrium model of money demand where the velocity of money changes in response to endogenous fluctuations in the interest rate. The parameter space can be divided into two subsets: one where velocity is constant as in standard cash-in-advance models, and another one where velocity fluctuates as in Baumol (1952). The model provides an explanation of why, for a sample of 79 countries, the correlation between the velocity of money and the inflation rate appears to be low, unlike common wisdom would suggest. The reason is the diverse transaction technologies available in different economies.

The use of triphenyltetrazolium chloride in the study of dehydrogenase activity of Brucellae

Experiments for the investigation of dehydrogenase activity of washed cells of a strains of Br. abortus and another of Br. suis in presence of different single added substrates are reported. The activity was measured as the amount of formazan produced by the reduction of 2, 3, 5-triphenyltetrazolum chloride acting as a hydrogen ions acceptor, at pH 7.0. In a general manner the dehydrogenase activity of Br. suis was much more intense than that of Br. abortus (fig. 5). In the conditions of the experiments Br. abortus oxidized L-arabinose, D-galactose, D-glucose, glycerol, D-xylose, DL-alanine, D-fructose, and D-sorbitol. Brucella suis oxidized D-xylose, L-arabinose, D-glucose, D-galactose, DL-alanine, sodium acetate, maltose, glycine, D-fructose, and D-sorbitol. Glycerol was oxidized by Br. abortus but its oxidation by Br. suir was very slight. Sodium acetate and maltose were intensely oxidized by Br. suir but not by Br. abortus. The sites of more intense enzymatic acitivity were seen as small red colored round granules located in one pole of the cells.

Methodological note about the determination of key sectors in final energy consumption: a preliminary approach to the Spanish case

In this paper we analyze the determination of "key" sectors in the final energy consumption. We approach this issue from an input-output perspective and we design a methodology based on the elasticities of the demands of final energy consumption. As an exercise, we apply the proposed methodology to the Spanish economy. The analysis allows us to indicate the greater or lesser relevance of the different sectors in the consumption of final energy, pointing out which sectors deserve greater attention in the Spanish case and showing the implications for energy policy.

On the stability of periodic orbits in Rn

We consider an autonomous differential system in Rn with a periodic orbit and we give a new method for computing the characteristic multipliers associated to it. Our method works when the periodic orbit is given by the transversal intersection of n ¡ 1 codimension one hypersurfaces and is an alternative to the use of the first order variational equations. We apply it to study the stability of the periodic orbits in several examples, including a periodic solution found by Steklov studying the rigid body dynamics.

Serological studies on an outbreak of smallpox in the State of Bahia - Brazil in 1969

Four weeks after Containment Vaccination undertaken against the largest outbreak of smallpox occured in Brazil in 1969, that of the municipality of Utinga, Bahia, 99 samples of serum were collected from the local population. These samples were classified in four groups: a) - Individuals with a history of variola prior to the beginning of present outbreak in town (15 sera); "Previous smallpox group"; b) - Individuals with primary vaccination, with no record variola, at the time of containment measures (15 sera). "Primary vaccinated group"; c) - Individuals with no previous record of variola revaccinated with "take" at the time of containment (15 sera0, "Revaccinated group"; d) - Individuals who contracted variola in present outbreak (54 sera) these were subdivided in four sub-groups, according to dates on which cases ocurred, "Variola in outbreak group". Serological study of samples was done by tests of hemagglutination inhibition, neutralization, and complement fixation. It was observed that HI titers were significantly lower in cases of previous smallpox than in other groups. Although they were slightly higher on revaccinated individuals than on primary vaccinated group and than in the group of variola in outbreak, this difference was not significant. Those same antibodies were present in all cases of variola in outbreak, and it was found that titers decreased in direct proportion to time elapsed from occurrence of cases. Neutralizing antibodies proved to be significantly higher on the revaccinated group than on variola in outbreak group, and higher on these than on primary vaccinated and on the previous smallpox groups. In cases from the variola in outbreak it was verified that neutralizing antibodies remained stable, although with great variation in titers. Tests of complement fixation could not be undertaken on all samples, because many of them proved to have anticomplementarity. However, it was found that complement fixing antibodies diminished rapidly, becoming negative for earlier infections. Finally, the authors suggest that there would be some evidence that HI titers are lower in variola minor under Brazilian conditions than in variola major.

Technical innovations at the service of cheaper labour in pre-industrial Europe. The Enlightened agenda to transform the gender division of labour in silk manufacturing

In 1749, Jacques de Vaucanson patented his or tour pour tirer la soie or spindle for silk reeling. In that same year he presented his invention to the Academy of the Sciences in Paris, of which he was a member1. Jacques de Vaucanson was born in Grenoble, France, in 1709, and died in Paris in 1782. In 1741 he had been appointed inspector of silk manufactures by Louis XV. He set about reorganizing the silk industry in France, in considerable difficulty at the time due to foreign competition. Given Vaucanson’s position, his invention was intended to replace the traditional Piémontes method, and had an immediate impact upon the silk industry in France and all over Europe.

Factors influencing the development of Plasmodium gallinaceum in Aedes fluviatilis

Aedes fluviatilis is susceptible to infection by Plasmodium gallinaceum and is a convenient insect host for the malaria parasite in countries where Aedees aegypti cannot be maintained in laboratories. In South America, for instance, the rearing of A. aegypti the main vector of urban yellow fever, is not advaisable because of the potential health hazard it represents. Our results of the comparative studies carried out between the sporogonic cycle produced with two lines of P. gallinaceum parasites into A. fuviatilis were as follows. As proved for A. aegypti, mosquito infection rates were variable when A. fluviatilis blood-fed on chicks infected with and old syringe-passaged strain of P. gallinaceum. Oocysts developed in 41% of those mosquitos and the mean peak of oocyst production was 56 per stomach. Salivary gland infections developed in about 6% of the mosquitos. The course of sporogony was unrelated to the size of the inoculum administered to chicks or to the route by which the birds were infected. The development of infected salivary glands was unrelated to oocyst production. Sporogony of P. gallinaceum was more uniform when mosquitos blood-fed on chicks infected with a sporozoite-passaged strain. Oocysts developed in about 50% of those mosquitoes and the mean peak of oocyst production was 138 per stomach, with some individuals having as many as 600-800 oocysts. Infected salivary glands developed in a mean of 27% of the mosquitos but, in some batches, was a high as 50%. Patterns of salivary gland parasitism were similar to those of oocyst production. The course of sporogony of P. gallinaceum in A. fluviatilis is analized in relation to degree of parasitemia and gametocytemia in the vertebrate host.