Showing papers by "University of Costa Rica published in 1983"
TL;DR: In this article, the authors describe the hydrography and exchange processes in a tropical estuary, the Gulf of Nicoya, Costa Rica, from data collected in 1979 and 1980.
Abstract: Hydrography and exchange processes in a tropical estuary, the Gulf of Nicoya, Costa Rica, are described from data collected in 1979 and 1980. The measurements and analyses were made in both the dry season and wet season and include temperature, salinity, and density at twenty locations in the gulf and currents (over a semi-diurnal tidal cycle) at five locations. These new results enlarge on the early study by Peterson (1958). Circulation in the lower gulf shows a marked east-west asymmetry due to the predominant runoff along its eastern shore from Rio Barranca and Tarcoles. The freshened surface water from the upper gulf combines with the runoff from these rivers and flows southward along the eastern side of the lower gulf. This flow is compensated by a northward flow of more saline water on the western side at all depths and on the eastern side along the bottom. The boundary between the southward and northward surface flow is marked by a strong salinity front in the rainy season. There is a rapid increase in tidal energy density toward the shoaling northern reaches of the lower gulf, between San Lucas Island and Puntarenas Peninsula. Enhanced mixing must accompany this increase, and direct measurements in the constriction between San Lucas and Puntaneras show that tidal mixing is dominant in transporting salt into the upper gulf against the freshwater runoff.
69 citations
Journal Article•
TL;DR: Experimental conditions for the comparative measurement of proteolytic activity of Costa Rican snake venoms on casein are established, and the activity of 13 different venoms is described.
Abstract: Experimental conditions for the comparative measurement of proteolytic activity of Costa Rican snake venoms on casein are established, and the activity of 13 different venoms is described Venoms showed marked differences in activity not only between species, but between specimens of the same species captured in different geographic regions of Costa Rica
65 citations
TL;DR: In this article, the authors studied the relationship between the amount and distribution of the lava and the ground morphology in basaltic andesite lava flows and derived a velocity profile in the channel and the frontal zone.
65 citations
TL;DR: The local effects induced by intramuscular inoculations of venoms from six species of coral snakes were studied in mice, finding that all these venoms induced a similar pattern of myonecrosis, characterized by a conspicuous alteration of the intracellular structure.
59 citations
TL;DR: Two hundred thirty-four of 242 neonates with a mean dehydration of 5.1% body weight were rehydrated with a glucose-electrolyte solution given orally in an average time of 7 44 hours, indicating oral rehydration is an entirely satisfactory choice for treatment of uncomplicated dehydration in neonates.
52 citations
TL;DR: In this paper, the authors measured ammonium, nitrite, nitrate, inorganic phosphate, and dissolved oxygen at 15 stations in the Gulf of Nicoya during rainy and dry seasons.
Abstract: Concentrations of ammonium, nitrite, nitrate, inorganic phosphate, and dissolved oxygen were measured at 15 stations in the Gulf of Nicoya during rainy and dry seasons. Results allowed division of the gulf into three areas. The upper gulf is an area greatly affected by changes in rainfall as levels of nutrients varied by an order of magnitude seasonally. The lower gulf shows less seasonal variation and is characterized by low concentrations of nutrients and high concentrations of oxygen at the surface and high concentrations of nutrients and low concentrations of oxygen at the bottom. Nutrient-rich bottom water in the lower gulf appears to be entrained from offshore by the positive estuarine character of the gulf. This process is facilitated by the extremely narrow shelf along the Pacific coast of Costa Rica. These oceanic waters are mixed vertically in the mid-gulf region and carried into the upper gulf by estuarine circulation.
46 citations
TL;DR: Peroxidase-bound protein A and lectins in combination with precipitable substrates were used to detect viral proteins and glycoproteins on 'Western blots' and this made this a useful choice for developing protein bands transferred to nitrocellulose paper.
45 citations
TL;DR: Venom from newborn snakes was devoid of hemorrhagic and edematigenous activities, whereas the venom from adult specimens induced these effects, and the ED50 of an antivenom was lower for the newborn specimens venom than for adult's venom, however, for each venom the number of LD50 neutralized was similar.
38 citations
TL;DR: Gravid female portunid crabs, Callinectes arcuatus, were held in a recirculating seawater system and the development of the eggs was observed, and an index was devised that predicted hatching date from microscopic observation of an egg mass.
Abstract: Gravid female portunid crabs, Callinectes arcuatus , were held in a recirculating seawater system and the development of the eggs was observed. Based on morphological criteria, nine developmental stages were noted. The relationship between a given stage and the subsequent time to hatching was determined. Based on this, an index was devised that predicted hatching date from microscopic observation of an egg mass. This index was used to predict the date of hatching of eggs from 439 crabs collected in the Gulf of Nicoya, Central America, and the frequency of hatching was analysed in relation to the lunar and tidal cycles. Significantly more eggs hatched during periods of spring than neap tides. The adaptive significance of this rhythmicity is unclear at present.
35 citations
TL;DR: Mature males of four species of pholcid spider, three Modisimus species and one of Blechroscelis, search out mature females and cohabit webs with them, and appear to induce the female not to leave, and thus make her defensible, as paired females' feeding rates are similar to those of solitary females.
Abstract: Mature males of four species of pholcid spider, three Modisimus species and one of Blechroscelis, search out mature females and cohabit webs with them. Males apparently compete for females. Males are dominant, but frequently cede prey to the females; paired males of at least two species feed less than solitary males. The function of this ‘chivalrous’ behavior is probably to induce the female not to leave, and thus make her defensible, as paired females' feeding rates are similar to those of solitary females.
32 citations
01 Jan 1983
TL;DR: The case of Melaleuca quinquenervia (melaleuca) in southern Florida is discussed, which was introduced in the early 20th century and has become naturalized and has spread over a vast area of wet land.
TL;DR: This paper hopes to clarify the taxonomic and geographic relationships of the various southern forms of Selasphorus, based upon a detailed examination of their plumages and information on their breeding distribution, annual cycles, and altitudinal movements.
Abstract: The breeding distributions of fiammula, simoni, and torridus are entirely allopatric, but the birds may occur together in the nonbreeding season. In particular, a pronounced postbreeding movement may carry many torridus into the breeding areas of fiammula and even simoni. A possible evolutionary history of these forms is proposed in relation to postPleistocene climatic changes, ecological requirements, and probable populations sizes. Received 7 June 1982, accepted 2 December 1982. THE genus Selasphorus, as presently defined by most authors, includes 6 or 7 species of small (2-31/2 g) hummingbirds with at least some rufous in the body plumage and tail; males have orange, red, or purple gorgets. Geographically, the genus comprises two groups of species: a northern group, whose three members breed in western North America, with one species extending south in the mountains to Guatemala; and a southern group in the mountains of Costa Rica and Panama. Most of the North American populations of the northern species rufus (Rufous Hummingbird), sasin (Allen's Hummingbird), and platycercus (Broad-tailed Hummingbird) are migratory, wintering mainly in western and central Mexico; the population of the latter species breeding in Mexico and Guatemala, however, is evidently resident. There is thus a gap of several hundred kilometers between the southernmost population of platycercus and the nearest populations of the southern group, which is not bridged by migration. The southern forms scintilla (Scintillant Hummingbird), simoni ("Cerise-throated Hummingbird"), fiammula (Volcano Hummingbird), torridus ("Heliotrope-throated Hummingbird"), and ardens (Glow-throated Hummingbird) are also 311 resident, although, as we shall see, they engage in regular altitudinal movements. Due to the great similarity between some species and the variability of others, the genus Selasphorus has a long history of taxonomic problems. Even in a relatively well-studied area like California, Allen's and Rufous hummingbirds were not recognized as distinct species until 1877. The southern group presents an even more complex picture, with the status of torridus and the affinities of simoni in particular still being debated. In this paper I hope to clarify the taxonomic and geographic relationships of the various southern forms of Selasphorus, based upon a detailed examination of their plumages and information on their breeding distribution, annual cycles, and altitudinal movements.
01 Jan 1983
TL;DR: A decline in the incidence of breast-feeding in many developing nations has been recorded in recent years, often in conjunction with rapid changes in way of life, migration from rural to urban centers, incorporation of women into the labor force, and increase in stress, anxiety, and violence in transitional and modern societies.
Abstract: A decline in the incidence of breast-feeding in many developing nations has been recorded in recent years, often in conjunction with (a) rapid changes in way of life, (b) migration from rural to urban centers, (c) incorporation of women into the labor force (especially in industry), and (d) increase in stress, anxiety, and violence in transitional and modern societies. The marked decline in incidence and duration of breast-feeding throughout the world is a matter of international concern. The importance of breast-feeding, particularly in developing societies, stems from its health-promoting effect, as it provides the best food known for infants, protects the child against a variety of debilitating infectious processes, and encourages attachment between mother and infant.1–6 Furthermore, successful breast-feeding indirectly reduces the ills of bottle-feeding, especially in developing nations, as epidemiological observation in many countries has revealed that early weaning is often associated with severe infant malnutrition, neglect, child abuse, abandonment, and premature death.7–9
TL;DR: The Poas Volcano in Costa Rica is one of the most interesting eruptive centers in the country due to the variety and peculiarity of its volcanic manifestations as discussed by the authors, which can be classified in four distinct categories: fumarolic, solphataric, pyroclastic and lava.
Abstract: The Poas Volcano in Costa Rica is one of the most interesting eruptive centers in the Country due to the variety and peculiarity of its volcanic manifestations. In this paper a short description of the structure of the active caldera and its relationship to the local geology is made. The volcanic activity shows a clear long period cyclic process. A bibliographic survey on the recent activity (from the beginning of the last century) of the volcano is also included. The activity may be classified in four distinct categories. a) fumarolic and/or solphataric. b) mud plumes. c) phreatic explosions (geyser-type). d) phreato-magmatic and lava eruptions. Analysis of the phenomena observed in 1980-81 suggest that the increase in temperature of the fumaroles from 92°C in December, 1980 to 960°C during the period March to November, 1981 was due to the rise and overflow of the fluids concentrated in the shallow magma body involved in the eruption of 1953. Fracturation of the solid part of the magma body had been shown by the local seismic activity beginning on July 27, 1980 and lasting about 10 days. It is finally suggested that all complex manifestations of this volcano are produced by the same eruptive mechanism.
Journal Article•
TL;DR: Pollinating insects of Sechium edule (Cucurbitaceae) were classified into primary and secondary according to their abundance and effectiveness as pollen collectors, with the most efficient species belonging in the low lands.
Abstract: Pollinating insects of Sechium edule (Cucurbitaceae) were classified into primary and secondary according to their abundance and effectiveness as pollen collectors. Among the total of 55 insect species found in Costa Rica pollinating the plant, 28 were identified as primary meliponid bees of the genus Trigona (Apidae), the rest were secondary pollinators: 15 species of wasps (Vespidae); 5 species of bees of the family Halictidae, 3 species of Anthophori da e and 4 species of Apidae. The plants were distributed altitudinally from almost 0 to 2000 m. As altitude increases, primary pollinators diminish; almost all were collected under 500 m; 30% of the secondary pollinators (the highest counts) were obtained over 1500 m.The higher, frequencies of pollinators (44.8 average) were observed between 500 and 999 m. The lower frequencies correspond to the low lands. Only four pollinators were really abundant: Trigona (Trigona) corvina, T. (Partamona) cupira, T. (Trigona) fulviventris and T. (Trigona) fuscipennis. The first two are the most efficient. These two species are abundant between 500 and 1000 m, where the best producing plants are found. Trigona fuscipennis belongs in the low lands and is the major pollinator there. Trigona fulviventris is less frequent between 500 and 1499 m and exhibits high frequencies in low and high altitudes. This peculiar distribution could be due · to the fact that this specie s is not aggressive and therefore less able to compete with Trigona corvina and T. cupira.
TL;DR: In this paper, the authors studied the spreading conditions that lead to the formation of rosettes in DNA and chromatin preparations from the amphibians Bufo marinus and Bolitoglossa subpalmata and the bacterium Shigella.
Abstract: We have studied the spreading conditions that lead to the formation of rosettes in DNA and chromatin preparations from the amphibians Bufo marinus and Bolitoglossa subpalmata and the bacterium Shigella. Both nuclear preparations and extensively deproteinized DNA produced rosettes. The longest fibers and the most symmetric rosettes were observed in amphibian nuclear spreadings. In this procedure purified nuclei were submitted immediately to Kleinschmidt spreading over various types of hypophase. Distilled-water hypophases were most conducive for rosette production or stability. Rosettes were observed with cytochrome C as the basic protein, but not with ribonuclease A and bovine serum albumin. We cannot prove that all rosettes are artifacts of the spreading procedure, but we believe that at least some result from the expansion of compact DNA doughnuts and other structures that are apparently formed in the presence of basic proteins in salt concentrations over 40 mM (Olins and Olins 1971; Manning 1979). The dilute hypophase requirement is explainable by the assumption that dilution and spreading effects unfold a compact precursor. Occasionally we have detected structures that appear to be intermediates in the process of doughnut unfolding and that illustrate a procedure that may give rise to rosettes.
Journal Article•
TL;DR: Trawl samples of demersal fish populations within the Gulf of Nicoya, Costa Rica were conducted during February and July, 1979 and April, 1980 in an attempt to define basic abundance, diversity and distributional patterns as mentioned in this paper.
Abstract: Trawl samples of demersal fish populations within the Gulf of Nicoya, Costa Rica were conducted during February and July, 1979 and April, 1980 in an attempt to define basic abundance, diversity and distributional patterns Seventeen day and three night samples produced 6,441 fishes of 107 species during the February cruise Twenty day and two night samples produced 9,220 individuals of 131 species during the July cruise Twenty day samples produced 14,151 individuals representing 125 species taken during the April cruise A total of 214 species were collected during this study The Gulf of Nicoya may be divided into three zones on the basis of the physical characteristics of the stations (water temperature, dissolved oxygen, salinity, depth and distance from the mouth of the Gulf) Few changes in the position of these zones occurred during the study period, indicating a relatively stableestuarine configuration from a biological perspective, under the influence of a wet and a dry season No significant seasonal changes in the number, biomass, percent occurrence, diversity of partitioning by size class of fishes were observed Two major types of fish distributional patterns were observed Several species were ubiquitous and were found throughout the Gulf in varying abundances Other species were restricted to either the upper or lower Gulf Dominant groups in the upper Gulf include the sciaenids, sea catfishes (Ariidae) and flatfishes (Soleidae, Cynoglossidae and Syacium ovale ) These fishes tend to inhabit the warmer, shallower, less saline waters of the upper Gulf Flounders (Bothidae), gobies ( Bollmannia spp), morays and congers ( Hildebrandia nitens , Priodonophus equatorialis and Muraenesox coniceps ) and several other species dominated the deeper, cooler, more saline lower Gulf
TL;DR: In this article, the aerial parts of Montanoa atriplicifolia were investigated and two pairs of isomeric cis-6,12-germa compounds were found.
01 Jan 1983
Journal Article•
TL;DR: A dynamic and multifactorial model is proposed to explain regional variations in cancer rates, with a tentative application of this model to the results obtained.
Abstract: An analysis of 1315 cases of gastric cancer from the records of the Ministry of Public Health, San Jose, Costa Rica between 1977 and 1980 showed important geographical differences in the incidence, and especially in relation to the sex ratio, age structure and migratory patterns. Rates of incidence ranged between 12.6 and 153.2 per 100,000 inhabitants in men and 10.6 and 56.6 in women. Variations in the incidence of gastric cancer rates were studied in relation to ecological parameters, including certain soil and drinking water characteristics as well as the presence of vitamins A and C in serum. No significant relation was found between gastric cancer rates and the presence of vitamins and of several components in drinking water. However, a multivariate analysis considering nine soil components and pH showed a statistically significant (p< 0.01) association with pH, K, Zn and Fe, which account for 22% of the variation in the incidence rates. A dynamic and multifactorial model is proposed to explain regional variations in cancer rates, with a: tentative application of this model to the results obtained.
01 Jan 1983
TL;DR: In this paper, the authors present an analysis of the relationship between the authorship of the arbitrado and the institution of Costa Rica, Instituto de Investigaciones en Salud.
Abstract: articulo (arbitrado) -- Universidad de Costa Rica, Instituto de Investigaciones en Salud. 1983
TL;DR: Decathieleanolide, a Dimeric Guaianolide from Decachaeta thieleana as discussed by the authors, is an unusual dimeric sesquiterpene lactone.
Journal Article•
TL;DR: The data obtained from Central American Pejibayes show that the rachis length of their fronds is considerably longer than those recorded from Surinam populations and it is assumed that at least part of this difference has a genotypic background.
Abstract: This is a preliminary study of the Pejibaye ( Bactris gasipaes ) frond and begins with a general morphological description of the Icaf, complementing those already in existence. The data obtained from Central American Pejibayes show that the rachis length of their fronds is considerably longer than those recorded from Surinam populations and it is assumed that at least part of this difference has a genotypic background. It was also found, contrary to expectations, that the older fronds have a longer rachis than younger mature ones from the same trunk. This difference could be due to seasonal environmental factors such as variations in rainfall. The association of leaflets in groups, each leaflet having a different angle of insertion on the rachis within the group, gives a many-planed leaflet arrangement that may increase light-use efficiency. The groups are formed by a variable number of leaflets and consequently are not a reliable character for use as a descriptor. The many-planed arrangement fades in old fronds when drooping of the leaflets increases, obscuring the effect of the different angles of insertion. It was also found that assymetry exists between opposite sides of the same frond in regard to leaflet number and length. An assymetrical frond outline is evident on both sides of the frond. A larger leaflet number was found in the younger fronds when compared with the older ones from the same plant in spite of the longer rachis of the latter ones. This may indicate that even 12 year-old palms have not reached the maximum development of their fronds since it is assumed that leaflet number is less affected by environmental variations than rachis length.
TL;DR: A worm found in histopathologic sections of the skin of a 31-year-old man in Honduras was identified as Paragonimus sp.
Abstract: A worm found in histopathologic sections of the skin of a 31-year-old man in Honduras was identified as Paragonimus sp. The worm was immature, and specific identification was not possible. This is the second human case of paragonimiasis in Honduras.
TL;DR: A comparative anatomical study of Laternea triscapa, L. pusilla and Ligiella rodrigueziana under light and scanning electron microscopy confirmed the validity of the genus LIGiella and the presence of an eight-spored basidium is reported and illustrated for the first time in Clathraceae.
Abstract: A comparative anatomical study of Laternea triscapa, L. pusilla and Ligiella rodrigueziana under light and scanning electron microscopy confirmed the validity of the genus Ligiella. The main differences between the two genera was established on the basis of the form, structure and location of the specialized glebiferous tissue, the glebiferous chamber and the gleba. The presence of an eight-spored basidium is reported and illustrated for the first time in Clathraceae. Description and illustration of sections of inmature fruiting bodies of the three species are included. The presence or absence of specialized glebiferous tissue is suggested as the starting point in the taxonomy of the Clathraceae.
TL;DR: This is the first comprehensive report on hallucinatory, edible and poisonous mushrooms of Costa Rica, which includes total number of intoxications per year, number of cases by age, sex and geographic distribution.
Abstract: This is the first comprehensive report on hallucinatory, edible and poisonous mushrooms of Costa Rica. A total of 67 species is reported of which 4 are hallucinatory, 55 are edible and 8 are poisonous. A search based on information obtained from national health centers between 1972 and 1977, includes total number of intoxications per year, number of cases by age, sex and geographic distribution.