Showing papers by "University of Costa Rica published in 1986"

The measurement of the etic aspects of individualism and collectivism across cultures

Abstract: The dimension of individualism-collectivism, as identified by Hofstede (1980), was studied using items developed both theoretically and emically in nine diverse cultures. The dimension was found to be analysable into four stable etic factors: Individualism had two aspects (Separation from Ingroups and Self-Reliance with Hedonism) and collectivism had two aspects (Family Integrity and Interdependence with Sociability). These four factors are orthogonal to each other. The location of nine cultures on these four factors was used to compute a “collectivism” score which correlated r = + · 73 with Hofstede's (1980) collectivism scores for the nine cultures. This approach enables the measurement of individualism-collectivism in each culture as well as across cultures, and shows that different methods for measuring individualism-collectivism converge.

A proposed use of ion exchange resins to measure nitrogen mineralization and nitrification in intact soil cores

Abstract: A procedure is proposed for measuring nitrogen mineralization and nitrification in intact soil cores. The method relies on ion exchange resins to trap ammonium and nitrate entering and leaving cores of soil otherwise open at the top and bottom. Changes in soil concentrations plus an accounting of ions trapped by the lower resin after field incubations, indicate rates of nitrogen reactions. Using this technique, we estimated net ammonification rates from 0–36 mg N/kg/mo and nitrification rates from 0–16 mg N/kg/mo for the surface of a sandy, low nutrient soil under pine cultivation in north Florida; higher rates occurred after urea fertilization. The procedure has potential advantages over others, but must be more fully evaluated under a variety of conditions.

Inflammatory infiltrate in skeletal muscle injected with Bothrops asper venom.

Abstract: The time-course and composition of inflammatory infiltrate in mouse gastrocnemius injected with Bothrops asper venom was studied. The venom induced myonecrosis, and a prominent decrease in muscle levels of creatine kinase (CK) as early as 3 hr after envenomation. Inflammatory infiltrate was scarce by 6 hr. but increased markedly at 24, 48 and 72 hr. Samples of infiltrate obtained at 6 and 24 hr contained polymorphonuclear leucocytes as the predominant cell type, whereas at 48 hr and 72 hr the relative number of macrophages increased. Inflammatory cells were located within necrotic muscle cells, as well as in the interstitial space, but there were some necrotic areas devoid of inflammatory cells even one week after envenomation. When correlating the presence of inflammatory cells with degradation of myofibrillar proteins, it was observed that at 6 hr there was little muscle protein degradation. By 48 hr a decrease in "non collagen" proteins was observed, together with a reduction in some myofibrillar components, as judged by electrophoresis. Proteolytic enzymes of inflammatory cells may play an important role in myofibrillar protein degradation after myonecrosis induced by B. asper venom.

Pollination by a hugging mechanism in Vigna vexillata ( Leguminosae-Papilionoideae )

Abstract: The pollination ofVigna vexillata (Leguminosae-Papilionoideae) by a carpenter bee,Xylocopa gualanensis (Hymenoptera-Anthophoridae) was studied in a secondary vegetation in Costa Rica The bees were observed foraging onV vexillata only in early mornings Visits on individual flowers lasted about 7–8 seconds Flower—pollen vector interactions are described and illustrated By its pressure on the left-hand wing- and keel-petal in the asymmetrical flower, the weight of the bee causes the upper bearded part of the style along with the upper free parts of the stamens to slip out of the rigid keel-beak, “hugging” the bee over the dorsal part of its head and thorax The occurrence of nototribic pollination inVigna and related genera is discussed

Single crystal x‐ray study of solid solutions of a Jahn‐Teller compound in an undistorted host: The Cr, Zn Saccharinate Hexahydrate System

Abstract: A series of phases of composition [M/M′(C7H4NO3S)2(H2O)4] · 2 H2O, where C7H4NO3S− is the anion of saccharine, have been prepared and studied by single crystal X-ray diffraction In addition to the end members, where M = M′ = Cr and M = M′ = Zn, the Cr/Zn mixed phases with atom percentages of Cr = 382(9), 493(8), 56(2), 63(1) and 69(1) have been structurally characterized The atom percentages were established from the X-ray data All crystals are based on a monoclinic unit cell in space group P21/c, the volume of which changes from 9904(9) A3 for 100% Cr to 9727(4) A3 for 100% Zn The Jahn-Teller distortion imposed by the Cr atoms is mainly localized in one pair of trans M — O bonds The significant and not necessarily expected feature of interest is that there is microscopic structural uniformity over all molecules in the mixed systems, rather than a disordered array of Cr- and Zn-containing molecules It is believed that the extensive hydrogen bond network in these crystals is instrumental in causing this result Einkristall-Rontgen-Untersuchung von festen Losungen einer Jahn-Teller-Verbindung in einem ungestorten Wirt: Das Cr, Zn-Saccharinat-Hexahydrat-System Eine Serie von Mischphasen der allgemeinen Zusammensetzung [M/M′(C7H4NO3S)2(H2O)4] · 2 H2O (C7H4NO3S ist das Anion von Saccharin) wurde dargestellt und rontgenkristallographisch untersucht Neben den reinen Phasen mit M = M′ = Cr und M = M′ = Zn wurden Cr/Zn Mischphasen charakterisiert, welche Chromanteile von 38,2(9), 49,3(8), 56(2), 63(1) und 69(1) Atomprozent enthielten Ihre Zusammensetzung wurde mit Hilfe von Rontgendaten bestimmt Alle untersuchten Kristalle sind isomorph und gehoren der monoklinen Raumgruppe P21/c an Ihre Zellvolumina variieren zwischen 990,4(9) A3 fur die reine Chrom- und 972,7(4) A3 fur die reine Zinkphase Der Jahn-Teller-Effekt, der durch die Chromatome verursacht wird, beschrankt sich im wesentlichen auf ein Paar trans-angeordneter M—O-Bindungen Von besonderem Interesse ist die Tatsache, das alle Molekule der Mischphasen mikroskopisch einheitlich erscheinen; d h die Kristalle sind nicht, wie man erwarten konnte, aus Zonen von ausschlieslich chrom- oder zinkhaltigen Molekulen mit daraus resultierender Fehlordnung aufgebaut Es wird angenommen, das das ausgedehnte H-Bruckennetzwerk fur dieses unerwartet Resultat verantwortlich ist

Late Miocene shore in northern Costa Rica: Benthic foraminiferal record

Abstract: In northern Costa Rica, the upper part of a volcaniclastic lithostratigraphic unit (Venado Formation) contains low-diversity benthic foraminiferal assemblages. The geologic age of these sediments is interpreted to be late Tortonian–Messinian (N17), on the basis of the 6.1 ± 0.6 Ma K-Ar age of a younger trachyandesite and an ostracode index genus from an older unit. The benthic foraminifera, in particular two ecophenotypes of Ammonia parkinsoniana (d9Orbigny), indicate that in the late Miocene, a shallow, brackish bay existed there, the shore lying to the north and west. The bay was an extension of the Caribbean Sea, already separated from the Pacific in this part of Costa Rica.

Dirofilaria from the index finger of a man in Costa Rica.

Abstract: A 4.5-cm male Dirofilaria indistinguishable from D. immitis was removed from the tip of the index finger of an 18-year-old farmer in Costa Rica. The case is reminiscent of a report of a larger (9-cm) but otherwise similar Dirofilaria, identified as D. spectans, a heartworm of otters, causing Raynaud's syndrome by occluding an artery of the fifth finger of a farm woman in Brazil. As in the present case, the worm was removed from a painful papule on the volar surface at the extreme tip of the affected finger.

Purification and Some Properties of Hemagglutinating Protein Mutina from Bushmaster Lachesis muta Snake Venom

Abstract: Lachesis muta snake venom induced aggregation of bromelain sensitized human erythrocytes al a concentration of 1 mg/ml. The hemagglutinating protein was purified by DEAE-Sephadex A-50 column chromatography. Polyacrylamide gel electrophoresis revealed at least three bands, whereas SDS electrophoresis in the presence of 2-mercaptoethanol showed a single one. Isoelectric focusing revealed hemagglutinating activity in the range of pH 3-8. The maximun peak (mutina) al pH 5.5. This fraction was active in agglutinating human RBC of types A, B. O Rh (+) and B. O Rh (-). One mM EDTA and 1 mM Ca ++ did not alter the agglutinating time significantly. Lactase and inositol inhibited the agglutination of A, S, O Rh (+) and B, O Rh (-) human RBC. The present study showed the non specificity of the hemagglutinating activity of mutina. It was also shown that mutina is a non-mitogenic protein.

Chemical Investigations of Tropical Medicinal Plants, XXI [1] Long Chain Alkyl Esters of Ferulic and p-Coumaric Acid from Bauhinia manca

Abstract: Abstract 17 Esters of ferulic acid and p-coum ric acid were isolated from the stem extract of Bauhinia manca ; the alcohol components range from C22H45 to C28H57.

Developmental Phases in the Life Cycle of Varroa Jacobsoni, an Ectoparasitic Mite on Honeybees

Abstract: (1986). Developmental Phases in the Life Cycle of Varroa Jacobsoni, an Ectoparasitic Mite on Honeybees. Bee World: Vol. 67, No. 3, pp. 92-97.

Non-enzymatic acetylation of proteins by aspirin as protection against the secondary complications of diabetes mellitus.

Abstract: The non-enzymic glycosylation of proteins has been implicated as a contributing pathogenia in the secondary complications of diabetes mellitus. The reversible acetylation of proteins by aspirin could slow down the advance of the biochemical lesion in well-controlled patients. The rate of acetylation of albumin by aspirin at 37 degrees C and pH = 7.30 was found to proceed two orders of magnitude faster than the glycosylation, providing a basis for therapeutic possibilities for the complications of diabetes mellitus.

Fenología y ecofisiología de Gliricidia sepium (Jacq. ) Steud, "Madero Negro" en Ciudad Colón, Costa Rica

Abstract: Leaf flushing, leaf fall, flowering and fruiting were observed during three years in a population of 20 trees of Gliricidia sepium growing in a coffee plantation in Ciudad Colon, Costa Rica (780masl) These four phenological characteristics showed a strong periodicity during the year with little variations in the period of the study Leaf fall occurs practically the year around, but it is more pronouced during dry season (December to March) Shoots grow constantly, but this process is more active during the wet season A positive correlation was determined bewtween shoot growth and soil humidity, but in the case of leaf fall this correlation was negative Flowering and fruiting occur during dry season (December-April) reaching a maximun on FebruaryIt is suggested that the phenology of this species is strongly correlated with soil humidity, but internal rhytms are al so considered important

Epidemiologia bucal y accesibilidad a los servicios odontologicos de un grupo de adolescentes

Abstract: The accesibility to dental services for 271 adolescent high school students from the province of Alajuela, Costa Rica was determined, and an epidemiological study of oral health was conducted. Dental caries were identified as the principal problem of oral morbidity; it showed an increase incidence with age. Ther are very few existing services for odontological care for this age group; it is therefore, necessary to create a specific dental health program that could provide for the needs of adolescents.

Purification and properties of a coagulant proteinase isolated from bushmaster (Lachesis muta) venom (Serpentes: Viperidae).

Abstract: The venom of Lachesis muta is a rich source of a thrombin-like enzyme. Its coagulant proteinase was purified by DEAE -Sephadex A -50 followed by agmatine CH -Sepharose and gel filtration on Sephadex G-100. On polyacrylamide gel electrophoresis at pH 8.4 a single band was observed. Its molecular weight by gel filtration was 49,000. The coagulant and esterolytic activities toward human fibrinogen and Tame of the inudasa were 662 NIH units/mg of protein and 4.37 delta OD225/min x 10(-3)/micrograms/ml, respectively. These values represent 23 and 5.7 fold increase over the crude venom. The enzyme mudasa, was evaluated with serum from human patients at Hospital Nacional de Ninos Dr. Carlos Saenz Herrera and found to be a valuable reagent for the quantification of fibrinogen on heparinized plasma.

Rhodnws Pallescens (Hemiptera: Reduviidae) in Costa Rica

Abstract: Rhodnius pallescens is added to the list of nondomiciliary triatomine bugs for Costa Rica. This species is considered the main vector of Chagas' disease in Panama.

Un caso de muerte de lenguas: el térraba

Abstract: La desaparacion de una lengua es un fenomeno etnologico no tan singular como a primera vista parece. A traves de la historia, se ha tenido noticia de decenas de lenguas que han sido sustituidas por otras en diversidad de condiciones.

Biología molecular del virus del rayado fino del maíz

Abstract: A condensed report of research on the molecular biology of Maize Rayado Fino Virus is offered, along with a tentative model for the capsid structure that fits the biochemical analysis of this virus. Given the existence of two capsid proteins present in a 7: 1 mass ratio it is suggested that in MRFV the major protein forms the closed icosahedral shell while the minor protein component is located externally.

Residuos de plaguicidas organoclorados en tejido adiposo humano en Costa Rica

Abstract: Mediante cromatografia gas-liquido se analizo los residuos de plaguicidas en 82 muestras de tejido adiposo humano obtenidas durante operaciones quirurgicas en 16 hospitales de Costa Rica. Se detecto los siguientes plaguicidas en las concentraciones que se incluyen: HCB 0,12 µ.g/g, γ-HCH 0,01 µ.g/g, epoxido de heptacloro 0,33 µ.g/g, α-clordano 0,01 p.g/g, dieldrin 0,12 µ.g/g, endrin 0,01 µ.g/g, p.p’-DDE 24,94 µ.g/g, o,p’-DDT 0,52 µ.g/g, p,p’-DDD 0,34 µ.g/g, p,p’- DDT 7,36 µ.g/g.De α-HCH y de heptacloro se obtuvieron valores insuficientes para calcular promedio. No se encontro concentraciones detectables de γ-clordano, aldrin y bifenilos policlorados.

Rat macrophage activity against Toxoplasma gondii studied by electron microscopy.

Abstract: Se hizo un estudio al microscopio electronico del efecto de los macrofagos de la rata blanca sobre el Toxoplasma gondii . Ratas blancas de un mes fueron inoculados i.p. con 10 7 taquizoitos y despues de 1, 2, 4, 8 y 24 horas se les extrajo el exudado periotoneal el cual fue procesado para el estudio al microscopio electronico de las celulas fagociticas infectadas. Los toxoplasmas observados dentro de los macrofagos de ratas mostraron lesiones muy evidentes tales como formacion de vacuolas y destruccion de la membrana celular. Este efecto fue aumentando conforme pasaba el tiempo de infeccion y ya despues de 8 horas todos los organismos estaban lisados. Estos resultados confirman a nivel molecular, la importancia de los macrofagos en la adaptacion natural de la rata blanca al T. gondii .