Showing papers by "University of Costa Rica published in 1978"
TL;DR: This paper addresses the question of how, and under what ecological circumstances, bird pollination will be optimal for a plant, and which or how many of the available nectar-feeding bird species will be ideal pollen vectors.
Abstract: This paper addresses the question of how, and under what ecological circumstances, bird pollination will be optimal for a plant, and which or how many of the available nectar-feeding bird species will be optimal pollen vectors.
Pollination by birds is energetically expensive for the plants, and should accur only when birds can mediate optimal patterns of pollen flow and seed set. Each nectar-feeding bird has potential advantages and disadvantages as a pollen vector, related to its size, morphology, and foraging behavior. Which available bird is the optimal pollinator depends on the plant's growth habit, spatial distribution, and breeding system. The various adaptations shown by plants favoring one pollinator over another all revolve around the secretion of nectar and the manner of presenting it to the birds. However, other aspects of plant morphology, physiology, ecology, or life cycle may affect the production and presentation of nectar, and influence plant-pollinator coevolution. Many question remain regarding the interrelations between pollination and the total biology of the plant; bird pollination systems may prove fruitful in yielding meaningful answers.
162 citations
TL;DR: In this article, a randomized double-blind trial, 51 5 -10% dehydrated infants were rehydrated with oral electrolyte solutions containing either sucrose or glucose, and most infants in both groups were successfully re hydrated, but the sucrose solution produced a slower correction of electrolyte abnormalities and a higher percentage of patients who needed more than 24 h of therapy.
76 citations
TL;DR: A total of eight satellite components and 11 minor components, accounting for 23% and 4% of the bovine genome, respectively, were thus isolated and charcterized in their relative amounts and buoyant densities.
Abstract: The dG+dC-rich fractions obtained by density gradient centrifugation of bovine DNA in Cs2SO4/BAMD [J. Cortadas, G. Macaya & G. Bernardi (1977) Eur. J. Biochem. 76, 13--19] were centrifuged in Cs2SO4/Ag+ density gradients. These experiments led to the preparation of the DNA components which had been detected (by analytical centrifugation in CsCl) in the Cs2SO4/BAMD fractions, and also of DNA components which had identical behaviors in Cs2SO4/BAMD gradients and identical buoyant densities in CsCl. A total of eight satellite components and 11 minor components, accounting for 23% and 4% of the bovine genome, respectively, were thus isolated and charcterized in their relative amounts and buoyant densities. The implications of these results on the interpretation of renaturation kinetic data on the bovine genome are discussed.
70 citations
TL;DR: Salamanders from five genera of Neotropical plethodontids carry a 5S gene cluster on the short arm of a large asymmetric chromosome, presumably a linkage group that has remained stable since the divergence of these genera in Tertiary time.
Abstract: Ribosomal 5S RNA, labelled with 125 I, was annealled to denatured spermatocyte chromosomes of salamanders from 11 different genera of the family Plethodontidae. The salamanders studied have genomes with 1, 2 or 3 gene clusters. Eleven sites are located interstitially on short chromosome arms; 3 are found interstitially on long arms; 5 sites are at centromeric regions and one is telomeric. — Salamanders from five genera of Neotropical plethodontids carry a 5S gene cluster on the short arm of a large asymmetric chromosome, presumably a linkage group that has remained stable since the divergence of these genera in Tertiary time. In Lineatriton lineola this short arm is heterochromatic during pachytene and it shows a high incidence of chiasma failure at the first meiotic metaphase, contrasting with the situation found in two other species. The localization and number of 5S gene sites is consistent with the proposed phylogeny of these Neotropical genera by Wake and Lynch (1976).
28 citations
TL;DR: A restriction enzyme analysis has led to the unambiguous identification of eight satellite DNA components and to new information on their repeat units, which indicates that identical repeat lengths are shared by them, a fact strongly suggesting a common origin.
Abstract: A restriction enzyme analysis was performed on satellite DNA components, isolated, as described in the preceding paper, from the bovine genome by a combination of Cs2SO4/BAMD and Cs2SO4/Ag+ density gradient centrifugation. Such an analysis has led to the unambiguous identification of eight satellite DNA components and to new information on their repeat units; this indicates that identical repeat lengths are shared by them, a fact strongly suggesting a common origin.
22 citations
17 citations
TL;DR: Results apparently indicate that L. muta from the Pacific lowlands of Costa Rica is more closely related to the South American subspecies than to that from the Atlantic versant.
14 citations
TL;DR: Additional studies showed that the presence of Eimeria falciformis, a common coccidian in domestic mice, did not inhibit the Toxoplasma infections in these rodents, and it is apparent that domestic mice and rats, besides the felines play an important role in the epidemiology ofToxoplasmosis in Costa Rica.
Abstract: A positive dye test for Toxoplasma antibodies was observed in 5% of 100 mice (Mus musculus) and 30.4% of 23 rats (Rattus norvegicus and R. rattus). The parasite was isolated from two mice. The animals were captured in several urban localities in the metropolitan area of San Jose, Costa Rica.The number of positive animals found appears to be enough to infect cats, whose principal source of infections are the Toxoplasma cysts in the rodents. Therefore it is apparent that domestic mice and rats, besides the relines play an important role in the epidemiology of Toxoplasmosis in Costa Rica. Additional studies showed that the presence of Eimeria falciformis, a common coccidian in domestic mice, did not inhibit the Toxoplasma infections in these rodents.
12 citations
8 citations
TL;DR: In this paper, a discussion reveals the need to review and substitute certain criteria currently med in Costa Rica in regards to nutritional recommendations; standards of weight; and classification and evaluation of the nutritional status.
Abstract: The present discussion reveals the need to review and substitute certain criteria currently med in Costa Rica in regards to: a) nutritional recommendations; b) standards of weight; and e) classification and evaluation of the nutritional status. Such concepts will lead to the adoption of alternate criteria and standards for a better assessment of malnutrition in children.Computation of the adequacy of the diet should be made as a function of the child's weight and not of his age (Sukhatme approach). The adoption of the Weight for Height and Height for Age criteria are recommended as a substitute for Weight for Age. The normal curves of weight and height of the National Center for Health Statistics (NCHS, USA) would be more accurate criteria.Systematic collections of weights and heights at the national level should be made, and the data processed by simple and rapid programs to discover and assess growth deficiencies.The philosophy and orientation, scientific basis, definition of target population, infrastructure and logistics of the nutrition intervention programs of Costa Rica, should be critically revised in the light of the present report. This particularly applies to the Program of Social Development and Family Allowances.
7 citations
TL;DR: The present situation of birth weight places Costa Rica among the countries in transition with a clearer perspective to attain an even higher infant survival in the near future and several measures oriented toward prevention of low birth weight are recommended.
Abstract: Costa Rica has experienced a marked reduction in infant mortality-both in the neonatal and post-neonatal components-in the last decade. The decline could be related to improvements in the pattern of fetal growth. The present report analyses the birth weight of newborns from a random sample of all births in the Republic of Costa Rica during 1970 and 1975. While the average birth weight in tha! period was 3100 grams, the prevalence of low birth weight ncanates decreased from 9 to 7 per ecot in fivc years. The provinces of Limon and San Jose exhibited lhe highest frequency of low birth weight. Women 20 to 29 years old had babies with bettcr or optimal body weight. Age, marital status and occupation of the mother appeared correlated with birth weight. A relationship betwenn changes in fetal growth and changes in maternal, perinatal and neonatal mortality is apparent. The present situation of birth weight places Costa Rica among the countries in transition with a clearer perspective to attain an even higher infant survival in the near future. In this regard, several measures oriented toward prevention of low birth weight are reeommended.
Journal Article•
TL;DR: Aguilar et al. as discussed by the authors investigated the use of un estudio sobre estructura socio ocupacional costarricense desde mediados del siglo pasado hasta la mitad del actual, to ampliar nuestra comprension de los cambios in los diversos sectores campesinos, artesanales, and asalariados in la produccion.
Abstract: Introduccion La investigacion, cuyos resultados generales se presentan a continuacion, tuvo por objetivo principal explorar la utilidad de un estudio sobre estructura socio ocupacional costarricense desde mediados del siglo pasado hasta la mitad del actual, para ampliar nuestra comprension de los cambios en los diversos sectores campesinos, artesanales y asalariados en la produccion. Pretende aportar elementos para ahondar, en estudios posteriores, sobre las formas de subordinacion indirecta y directa del trabajo al capital en el caso costarricense, el replanteamiento de la cuestion nacional durante el periodo mencionado y el entrelazamiento de las reivindicaciones populares y antiimperialistas en el nivel de los interes fundamentales que no siempre en el de la consciencia y la practica politicas
TL;DR: Observation on 100 streams in Costa Rica over a two-year period indicated no strong correlations of either larval populations al biting adults with such stream factors as substrate, tcmperaturc, altitudes, water speed and turbulence, pollution of shade.
Abstract: Observation on 100 streams in Costa Rica over a two-year period indicated no strong correlations of either larval populations al biting adults with such stream factors as substrate, tcmperaturc, altitudc. water speed and turbulence, pollution of shade. Small differences and sorne reversals in the datasuggest only trends.
01 Oct 1978
TL;DR: During meiosis and espermiogenesis the Golgi apparatus show-s the greatest morphological and physiological changes, while the spermatid practically continues occupying the same position in the cellular association of the seminiferous tubule.
Abstract: During meiosis and espermiogenesis the Golgi apparatus show-s the greatest morphological and physiological changes. During the second meiotic division it appears as a very large organelle, formed by prominent dictyosomes and by two types of vesicles: one in the external part of the body with diameters that range from 40-100 nm, and the other in the central part of the organelle, larger in size, from 200 to 500 nm. The acrosome, once formed, is spheric (1600 nm in diameter) with the glycoproteins forming a round and dense body occupying its central zone. Later the acrosome moves against the nuclear membrane. These morphological changes occur within a very short time, while the spermatid practically continues occupying the same position in the cellular association of the seminiferous tubule.
TL;DR: Hb Suresnes was detected by electrophoresis in a 6 year old boy who was found by routine hematological examination to have an abnormal RBC count and Hb concentration.
Abstract: The first example of hemoglobin Suresnes, α2 141 (HC3) Arg → His β2, has recently been reported by Poyart et al (1). Hb Suresnes was detected by electrophoresis in a 6 year old boy who was found by routine hematological examination to have an abnormal RBC count and Hb concentration. The propositus and the two other members of the family who also had the variant did not show any clinical symptoms.
TL;DR: Four species of Lycoperdaceae are described from North Central Florida: Calvatia cyathiformis (Bose.), Disciseda bovista (KI.) Henn.
Abstract: Four species of Lycoperdaceae are described from North Central Florida: Calvatia cyathiformis (Bose.) Morgan C. cyathiformis Zeller & Smith, Disciseda bovista (KI.) Henn., D. pedicellata (Morgan) Hollos and D. verrucosa Cunningham. A key to the North Central Florida genera of Lycoperdaceae is provided.
TL;DR: In fact, Kant nunca se fijo el proposito de abordar en serio el campo de la filosofia de la Historial lo que es mas, parece sentirse desgarrado por Herder al tener que desligarse de sus propios intereses and abocarse a una polemica que le lleva a plantearse problemas de filosoffa de la historia alejandose del camino que se habia propuesto as discussed by the authors.
Abstract: Como sucede con Maquiavelo, uno termina por ver en Kant a un historiador a pesar suyo. Kant nunca se fijo el proposito de abordar en serio el campo de la filosofia de la Historial lo que es mas, parece sentirse desgarrado por Herder al tener que desligarse de sus propios intereses y abocarse a una polemica que le lleva a plantearse problemas de filosoffa de la historia alejandose del camino que se habia propuesto.
TL;DR: In this article, the authors present a Coincidence-Anticipation Apparatus for a Gross Motor Task (CAT) for the task of estimating the probability of a motor stroke.
Abstract: (1978). Coincidence-Anticipation Apparatus for a Gross Motor Task. Research Quarterly. American Alliance for Health, Physical Education and Recreation: Vol. 49, No. 2, pp. 240-245.
Book•
01 Jan 1978TL;DR: The hospital records of 478 children with protein-calorie malnutrition (PCM) were reviewed and found that a considerable number of children belonged to "malnourishing families" which have particular characteristics favorable to establishment of malnutrition in the family.
Abstract: The hospital records of 478 children with protein-calorie malnutrition (PCM) were reviewed. These represented all children diagnosed as malnourished during 1975 (3.6 per cent of all hospital admittances in the National Children’s Hospital); 52% of the cases were infants less than 6 months of age; 28% had low birth weight, a rate much in excess of the prevalence of low birth weight in the general population of Costa Rica (7%). In general, malnourished children had been weaned early, 75% during the first month of life. A considerable number of children belonged to "malnourishing families" which have particular characteristics favorable to establishment of malnutrition in the family. Thus, 36% of their siblings had also been admitted with malnutrition at a previous date to that of this study.
TL;DR: Calorie defficiencies of children benefiting from this program were of similar magnitude as those of children not attending the food distribution centers, which point to the need to carry out further investigation of the actual effectiveness and drawbacks of such programs.
Abstract: Six Costa Rican communities of different ecological,-" settings were selected for the study of road intake in children under 5 years of age. Intake was expressed as calorie and protein adequacy. Calorie defficiency was more prevalent than protein defficiency. Practically there were no differences in adequacy by age, although 4 year-olds had a slightly greater defficiency than younger children. Calorie and protein intake was lower in this study than observed in a. relatively more advanced rural region 4 years earlier. Only 13 per cent of the children selected at random were covered by Social Development and Family Allowances programs which provide for two "hot meals" per day. Calorie defficiencies of children benefiting from this program were of similar magnitude as those of children not attending the food distribution centers. These observations point to the need to carry out further investigation of the actual effectiveness and drawbacks of such programs.
TL;DR: A study of consanguinity and population structure was carried out in a sample of 498 consanguineous and 570 non-consanguineously matings in the Parrish of Dota, Costa Rica, during a period of 75 years, finding that there is a high frequency of unions among second cousins and exogamy tends to diminish with time among both types of union.
Abstract: A study of consanguinity and population structure was carried out in a sample of 498 consanguineous (MC) and 570 non-consanguineous matings (MNC) in the Parrish of Dota, Costa Rica, during a period of 75 years. The inbreeding coefficient (F) shows fluctuations in time (476 to 194 x 10-5) with an increase from 1888 to 1917, followed by a decrease in the last years but remains high in nonmigrant marriages. There is a high frequency of unions among second cousins. The endogamy percentage is high, greater in MC (80%) than in MNC (61%). Exogamy tends to diminish with time among both types of union. Effects of age distributions in the groups were not found. Marital and migrational distances are short and tend to become shorter in the final periods. There is a positive correlation (r = 0,71 ; p <0,05) between these distances in MC but not in MNC; distances are shorter in MC. Inmigration is minimal and reduced to short distances. Post-marital movement is intense (37% and involves greater distances. Emigratory behavior is identical in MC and MNC.