Showing papers by "University of Costa Rica published in 1985"

Patterns of Distribution of the Central American Ichthyofauna

Abstract: In a previous paper dealing with the biogeography of the ichthyofauna of the San Juan Province of Central America, I analyzed the vicariant patterns of distribution, in light of paleogeologic knowledge in order to determine the origin of historical faunal elements and the barriers responsible for these patterns. Some general conclusions reached at that time were that: (1) an ancient South American Element dispersed into Central America during Late Cretaceous or Paleocene times; (2) Central America was later isolated from South America during most of the Tertiary; (3) land masses south of the Nicaraguan Depression remained emergent throughout the Tertiary; and that (4) the two continents were reunited by the closure of the Bolivar seaway in Pliocene time.

Patrones regionales en la estructura y composición florística de los manglares de la Costa Pacífica de Costa Rica

Abstract: El presente estudio tiene como objetivo describir y cuantificar las caracteristicas estructurales y la composicion floristica de los manglares de la costa Pacifica de Costa Rica; asi como determinar la influencia de factores climaticos e hidrologicos sobre ellas.Este estudio sugiere que muchas de las especies de la vegetacion marginal estan obligatoriamente asociadas a los manglares, y deben ser incluidas como parte de la vegetacion propia de este ecosistema. La dependencia entre la distribucion de muchas de las especies marginales y la vegetacion nuclear sugiere un largo proceso evolutivo que se hace evidente e n la presencia de adaptaciones tales como viviparidad en Crinum e Hymenocallis, frutos flotantes en T. palustris, P. phellosperma y D. latifolius (bignoniaceae).

Cryptosporidiosis in Venezuelan children with acute diarrhea.

Abstract: Thirteen of 120 Venezuelan children with acute diarrhea were found to be excreting Cryptosporidium oocysts in their stools. This confirms that Cryptosporidium can infect immunocompetent children, and the relatively high frequency found suggests that this protozoan may be an important cause of diarrhea in Venezuela.

Low Endemicity and Low Pathogenicity of Rotaviruses Among Rural Children in Costa Rica

Abstract: Articulo cientifico -- Universidad de Costa Rica. Instituto de Investigaciones en Salud. 1985

Temporal and spatial rainfall variability in the mountainous region of the reventazón river basin, costa rica

Abstract: Two seasonal periods with different rainfall characteristics were identified in the mountainous region of the Reventazon River basin, Costa Rica, a region of about 1770km2 with altitudes in the 50O-3000km range. These seasonal periods are December-April, in which orographic rain predominates, and May-November, in which convective showers predominate. The temporal variability of rainfall in the study area was examined using the coefficient of variation. It was found that the largest values of the coefficient of variation occur at high altitudes and the lowest values at middle altitudes. They are large in the December-April period and small in the May-November period. Correlation analysis was used to determine the spatial variability of rainfall in the study area. The results obtained show that the monthly and seasonal values of the correlation coefficient are generally larger than 0.7 over the study area in the December-April period. In the May-November period, the values of the correlation coefficient are in general quite small, less than 0-3 for distances less than 50 km in the case of seasonal totals. In this latter period, a few values of the correlation coefficient larger than 0.7 are observed, but they correspond to areas with correlation radii less than 3 km.

Population biology of the portunid crab Callinectes arcuatus Ordway in the Gulf of Nicoya, Costa Rica, Central America

Abstract: Tropical blue crabs Callinectes arcuatus were collected by trawling in the Gulf of Nicoya on the Pacific coast of Costa Rica, Central America. The gulf population was generally dominated by females. Adult females were common in the upper, more estuarine regions of the gulf during rainy season, but appeared to migrate to the lower gulf during dry season for spawning. Biomass varied with seasonal changes in abundance, but was generally similar to biomass of C. sapidus in Chesapeake Bay. Analysis of size frequency indicated that the population is numerically dominated by adults during January and February and that juveniles are common during the remainder of the year. Extrapolation of available data suggests that female crabs reach maturity in approximately one year after hatching.

Investigaciones geofisicas y caracteristicas geoquimicas de las aguas hidrotermales: volcan poas, costa rica

Abstract: A geophysical and geochemical preliminar research has been carried out in the active caldera of Poas volcano during 1980-82. The water of the intra-caldera lake has a very strong acidity (pH <1) due to the high content of Cl-and SO 4 -2 . The concentration of metal cations is considerably high as well. Temperature calculated (T = 229°C), by means of chemical geothermometer for the mixing of phreatic waters with hot fluids, are in the range of those detected in geothermal systems associated to andesitic rocks. The temperature increase from 92°C (December, 1980) to 960°C (March-November, 1981) in the N-E section of the lava dome seems to be related to the fracturing (probably connected to the seismic crisis of July, 1980) of the upper plug of the cooling magma body at depth. This mechanism induced the exolution of relatively high temperature gaseous phases from below. Near surface oxidation phenomena might have been effective, thus contributing to increase the temperature of gases. Magnetic measurements confirm that the temperature increase was superficial and confined within a small area surrounding the central dome. In the light of the data hereby presented we suggest that the local temperature increase (from 92°C to 960°C) does not have any implication with magma ascent.

Regularization and distributional derivatives of (x12+x22+ . . . +xp2)–½n in R p

Abstract: Our main aim is to present the value of the distributional derivative ∂ N /∂ x 1 k 1 ∂ x 2 k 2 . . . ∂ x p k p (1/ r n ), where r = ( x 1 2 + x 2 2 + . . . + x p 2 ) ½ in R p , N = k 1 + k 2 + . . . + K p , and p , n , k 1 , k 2 , . . ., k p are positive integers. For this purpose, we first define a regularization of 1/ x n in R 1 , which in turn helps us to define the regularization of 1/ r n in R p . These regularizations are achieved as asymptotic limits of the truncated functions H ( x – ∊)/ x n and H ( r –∊)/ r n as ϵ → 0, plus certain terms concentrated at the origin, where H is the Heaviside function. In the process of the derivation of the distributional derivative formula mentioned, we also derive many other interesting results and introduce some simplifying notation.

Organismos de los arrecifes coralinos de costa rica. Iv. Descripcion y distribucion geografica de octocoralarios (cnidaria : anthozoa) de la costa caribe

Abstract: A complete survey of the shallow-water octocorallian coráis was conducted during 1983 and 1984 along the Caribbean coast of Costa Rica. The distribution of these orgamsms was observed to be I imited to hard substrates, because the colonias were found only south from Main to Punta Mona, wherecoral reefsand rocky áreas exist. Twenty five species are described with so me notes about is habitat. Species were determinad accordíng to the morphology of the colony and the distint patterns of spiculation. The highest diversity (S) was found at Uvita Island and Cahuita reefs, where almost all the species are representad. The population of Erythropodium caribaeorum was found to be relatively abundant and widely distributed. Numerosos estudios sobre la fauna octocoralaria del Caribe se han realizado, siendo el más importante el de Bayer (1961), quien actualiza la taxonomía de estos organismos describiendo un total de 96 especies para la región. Si se agregan al listado de especies de aguas superficiales (Bayer, 1961) las de aguas profundas (Deichman, 1936), se obtienen un total de 196 species para el área. Actualmente hay descritas 2.000 especies de octocoralarios para el mundo y quizás un número similar por ser descritas (Bayer, 1981). En la costa Atlántica de America Central, existen formaciones arrecifales con diversidad considerable, entre los cuales se puede citar los de Bel ice. Honduras y Panamá. Sin embargo, sólo existen tres trabajos sobre octocoralarios: Belice con 36 especies informadas (Muzik, 1982), Honduras con 12 especies (Tortora y Keith, 1980), y un informe sobre Cahuita, Costa Rica con 4 especies {Wellington, 1974). Contribución del Centro de Investigación en Ciencias del Mar y Limnología (CIMAR), Universidad de Costa Rica.

Estimación del área foliar de la palma de pejibaye ( Bactris gasipaes H.B.K.)

Abstract: In the African oil palm, leaf area is correlated to production, and nondestructive methods of estimating area have been developed. It may be assumed that this is true for pejibaye ( Bactris gasipaes ). In a test of these methods and a modification of one of them for use with pejibaye, leaflet areas were regressed against leaflet length by maximum width. These coefficients were found to be constant within and between trees, and averaged 0.72. Leaflet sub-samples were found to be equal to average data. Leaf area was regressed against length by maximum width of different leaflet sub-samples times the number of leaflets. The different methods tested produce regression coefficients with little variaton between them. Use of these coefficients to estimate the area of another leaf of the same tree gave good results, as did the use of the average regression coefficient for each method. Since it is also easier to use on pejibaye, this modification is recommended for future studies. This coefficient, for use in Central American pejibaye, is 0.583.

Pulmonary dirofilariasis in a Costa Rican man.

Abstract: In a 33-year-old male Costa Rican who died of undetermined cause 2 hours after admission to hospital, autopsy revealed a small female Dirofilaria causing a recent hemorrhagic infarct unlike the pale coin lesion usually seen in pulmonary dirofilariasis.

Las abejas Peponapis y Xenoglossa en Costa Rica y su importancia en la polinización de las Cucurbita domésticas

Abstract: The squash and gourd bees, endemic to the Americas, are represented by 20 species, five of which are found in Costa Rica: four in the genus Peponapis and one in Xenoglossa. Since these two genera show a very close relationship, a series of common biological and morphological characters are given. According to the studies of Hurd and Linsley the majority of species (16) are found in Mexico, where the maximum development of Cucurbita occurs. This fact suggests that both plants and bees had their origin in Mexico, from where they migrated South and North. Keys are presented for identification of both sexes of the Costa Rican species. Additional information includes synonymical bibliographies and references. The squash and gourd bees virtually derive their entire economy from Cucurbita. Adaptive evolution between these bees and the flowers of Cucurbita is also shown, making the closely related genera Peponapis and Xenoglossa the best pollinators for the domestic or cultivated Cucurbita. Peponapis limitaris seems to be the best pollinator in Costa Rica, due to its wide distribution and abundance in this country, while Peponapis apiculata appears the better pollinator of Cucurbita ficifolia (chiverre) , which is cultivated at altitudes above 1000 meters.

Extraccion de algunos nematodos fitoparasitos mediante modificaciones de las tecnicas de centrifugacion - flotacion y embudo de baermann modificado

Abstract: Extraction of some plant-parasitic nematodes by modifications of the flotation-centrifugation and modified Baermann funnel techniques. The comparative efficiency of the modified Baermann funnel (MBF) and flotationcentrifugation (FC) nematode extracting methods, as well as some modifications, was evaluated. Modifications included sample size (50, 100 or 150 ml of soil), number of sample washings (I, 2 or 3), suspension time before washings (20, 40 or 60 s) and sieve arrangement (A = one 50 and two 325 mesh; B = one 100 and two 325 mesh, and C =one 100 and one 325 mesh) for both methods. Centrifugation time (3, 4 or 5 min at 3.000 rpm) and specific gravity of the sugar solution (1.12, 1.15 or 1.18) were evaluated for the FC technique only. With the MBF method significantly higher densities of Helicotylenchus sp., Trichodorus sp. and Rotylenchulus reniformis were recovered with 50 cc soil samples, and significantly more Helicotylenchus sp. and R. reniformis were recovered with 3 washings and the B sieve arrangement, respectively. With the FC method, significantly higher densities of Helicotylenchus sp. were extracted by the 50 ml sample size, 60 s of suspension before washings, 4 min of centrifugation and 1.15 specific gravity. precision de los analisis (1). Con el fin de obtener INTRODUCCION una mayor informacion acerca del efecto de algunas modificaciones de los metodos de extracci6n En Cost,a.Rica los dafios cau,sados por.nematradicionales sabre la recuperaci6n de otros nematodos fitoparasrtos cobran cada dla mayor Importodos comunmente encontrados en nuestros tancia debido a la cantidad de cultivos que se ven suelos se IIev6 a cabo esta investigaci6n. . afectados, tanto en su rendimiento como en su ' calidad (3, 8, 9). Recientemente se ha encontrado MATERIALES Y METODOS que los metodos de extracci6n afectan la determinaci6n de las densidades de los nematodos y la Se colecto muestras de suelo en una serie de plantaciones donde previamente se habia detectado infestaciones de ciertos nematodos fitopara1/ Recibido para su publicacion cl 14 de enero de sitos. estas fueron trasladadas posteriormente alla1985. b '. d d f h . d t oratorIo on e ueron omogenelZa as y cuar ea. Parte de una tesis de grado presentada por el pridas hasta obtener las submuestras correspondienmer autor ante la Escuela de Fitotecnia de la tes. Universidad e Costa Rica. En el Cuadra 1 se presentan algunas caracte.. Laboratorio de Nematologia, Escuela de Fitotec-' ristic~s de los suelos utilizado!:.e.n este estudio. Las nia, Universidad e Costa Rica, San Jose, Costa especles de nematodos y los SltlOS donde se colecRica. taron fueron los siguientes: Criconemella sp. en 176 AGRONOMIA COSTARRICENSE Palmira de Alfaro Ruiz (C-P); Helicotylenchus sp. He-ZAR, respectivamente) y Rotylenchulus renien Santa Ana (H-SA); Trichodorus sp. y Hetero[armis Linford & Oliveira en Orotina (Rr-O). Los dera sp. en Zarcero de Alfaro Ruiz (Tr-ZAR y hospedantes donde se encontraron fueron, respectivamente: pasto kikuyo (Pennisetum clandesCuadro 1. Algunas caractensticas de los suelos donde tinum Hochst)., tomate (Lycopersicon esculenfueron colectad~ las e.spe~ies de, nematodo,s tum Mill) papa (Solanum tuberosum L.) y papaya con que se evaluo 1a eflcacla de clertas modl.' ficaciones de dos metodos de extraccion. (Carica papaya L.). Se compar6 la eficacia de dos metodos de extracci6n de nematodos del suelo para cad a una , , Localidad de las especies mencionadas previamente. Estos Caractenstlcas , d f 1 d .f .6 fl ., Palmira Santa Zarcero Orotina meta os ueron e e centn ugaci notaclon en de Alfaro Ana de Alfaro soluci6n azucarada y el del embudo de Baermann Ruiz Ruiz modificado por Christie y Perry, de acuerdo con las descripciones dadas pOT Alvarado y L6pez (1). Nombre franco franco franco franco . bl 1 d d ' d d t t al e so arcilloso arcillo arcilloso Las varIa es eva ua as con ca a meto 0 e exex ur ar , 1 . ' d 1d. arenoso traccion, as comparaclones entre me to os, e 1serio experirrlental y el analisis estadistico utiliArcna (%) 48,5 35,1 36,8 39,7 zados ya fueron descritos ~n un trabajo previo (1). Limo (%) 25,9 32,1 27,8 25,6 Arcilla (%) 25,6 32,8 35,4 34,7 RESULTADOS Mat,cr~a(OJ') 6 3 4 2 3 2 2 8 Embudo de Baermann modificado (EBM) orgamca 70 , , , , H2O 6,1 6,4 6,0 5,9 En el Cuadro 2 se pr~senta el efecto del tapH mafio de la muestra, del numero de lavados de la KCL 5,3 5,6 5,0 5,1 muestra, del tiempo de suspensi6n antes de los lavados y del arreglo de las cribas sobre el numero Sub-Orden Andcpt Ustropcpt Andcpt Ustropcpt promedio de carla especie, extraido par la tecnica Cuadro 2, Influencia de ciertas modificaciones oble el numero promedio de algunos nematodos fitoparasitos recuperados pOl 1a tecnica del Embudo de Baermann modificado. Espccie de* Tamaiio de muestra Numeros de lavados Tiempo de suspension Arreglo de Cribas*** nematodo (ml) (s) 50 100 150 I 2 3 20\" 40\" 60\" ABC C-PZ 5 a** 3 a 3 a 5 a 6 a 5 a 6 a 4 a 6 a 5 a 6 a 4 a H-SA 215 a 174 a 80 a 418 b 505 ab 647 a 258 a 283 a 219 a 592 a 809 a 819 a Hc-ZAR 26 a 36 a 40 a 46 a 45 a 55 a 46 a 40 a 20 a 50 a 45 a 46 a Tr-ZAR 29a 20a 9b 51 a 48a 51 a 48a 33a 42a 45 a 40a 38b Rr-O 1020 a 790 ab 605 b 1225 a 1289 a 1444 a 1702 a 1600 a 1865 a 1245 ab 1349 a 689 b * C-PZ (Criconemella sp. dc Palmira dc Zarccro): H-SA (Helicotylenchus p. de Santa Ana); He-ZAR (Heterodera dc Zarccro dc Alfaro Ruiz); Tr-ZAR (Trichodorus sp. de Zarccro de Alfaro Ruiz); Rr-O (Rotylenchus reniformis de Orotina). ** Promcdio dc cinco rcpcticioncs. Promcdios cn una misma linea para una misma variable. seguidos pOl una misma Ictra, no dificrcn significativamcntc entre si de acuerdo con los resultados de la prueba de amplitud mUltiple de Duncan (P =0,05). Densidadcs promcdio cxprcsadas cn numero de nematodosj100 ml de suelo. *** A: 50-325-325 mesh; B: 100-325-325 mesh; C: 100-325 mesh. ALVARADO y LOPEZ: Tecnicas de extracci6n de nematodos 177 EBM, Se encontr6 que con un volumen de 50 ml po de suspensi6n antes de log lavados, de la gravese recuperaron significativamente mas H-SA, dad especffica de la solucion azucarada y del tiemTr-ZAR y Rr-O que con ISO rnl; al estirnar la po de centrifugacion sabre la extraccion de log netendencia de recuperacion de estas especies e enmatodos par el metoda CF se presenta en el Cuacontraron efectos lineales negativos, definidro 3, dog respectivamente par lag ecuaciones Para lag comparaciones del numero de lavaY = 12,27-14,24Xl, Y = 4,28-5,93Xl Y dog no bubo diferencias significativas enla extracY = 28,21-18,36Xl, cion de log nematodos estudiados, Se recupero sigEn cuanto a lag otras comparaciones del tanificativamente mas H-SA con un volumen de 50 , rnl que con 1000 ISO rnl' en este caso se encontro mafia de la muestra, con respecto alas especles ..\" ,', \" , , t t h b d'\" ' \" ' f ' t \" un electo Imeal negatlvo, defmldo par la ecuaClon resanesno u 0 llerenclasslgmlcalvas, Y=1443-1\"06X' E tIt Par otra parte, se obtuvo una cantidad signi\" -', 1, n cuan 0 a as 0 rag compaficativamente mayor de H-SA con 3 lavados que raclo~es del tamafio,de la ~ue~tra, ~n l~s restantes con uno solo; el numero de lavados tuvo un efecto especl,es, no bubo dlferenclas slgn~~lCatlVas, Se enI ' 1 't ' 1 '6 d H SA contra que con 60 s de suspensl0n antes de log mea pOSI IVO en a recuperacI n e , , \" , , d fi ' d 1 \" Y 16 I 8 8IX lavados se recuperaron slgmflcatlvamente mas e ml 0 par a ecuaCl0n 1 ' .\" \" .','\" H-SA que con 20 s; al estudlar su comportamlenNo se encontro dlferenclas slgmficatlvas en to en 1 C ' , t ' .. t \" a re uperaClon, se encon ro un elec 0 cuanto alas otras comparacl0nes del numero de li 1 ' t ' d fi \" d I ' , , nea pOSI lVO, e ml 0 par a ecuaCl0n lavados para las espeCles restantes, Para lag compaY =3 44 + 4 15X Serecupe ' , ' f ' t ' t , d 1 \" d ' , h b d '\" ,,1 ' ro slgm lca lvamen e raclones e tlempo e suspenslon no u 0 llema' s TrZAR conun t 'em de \" d 40 , \" fi ' I \" 1 po suspenslon e s renclas slgm lcatlvas en a extraccl0n, aunque se quecon 20 S No t ' d' f ' , ' fi , \" , se encon ro 1 erenclas slgm lcaobtuvo mayor recuperaclon con un tlempo de sus, , , \" d 20 S ' d ' d d \" fi tlvas en cuanto alas otras comparaclones del tlempenSIon e s, e recupero una ensl a slgm 1d ' , , d R 0 1 gl d ' po e suspenslon, catlvamente mayor e rcon e arre 0 e cn1 . , b B ( d 100 d d 325 h) 1 En 0 concernlente al arreglo de cnbas, con as una e y os e mes que con e ( C ( d 100 d 325 h) E 1 t el A una de 50 y dog de 325 mesh) se recuperaron una e y una e mes, n as 0 rag \" fi ' , H ZAR 1 B N , , , slgm lcatlvamente mas eque con e , 0 comparacl0nes del arreglo de cnbas no se encontro '\" \", , d' f \"' fi t . 1 se encontro duerenclas slgnulcatlV2s en cuanto a 1 erencla slgm lca lva a guna, \" lag otras comparaClones del arreglo de cnbas para C rif \" fl \" 1 \" da lag otras especies, ent ugaclonotaclon en so UClon azucara (CF) Se recuperaron significativamente mas La influencia del tamafio de la muestra, del H-SA con un tiempo de centrifugaci6n de 4 min numero de lavados, del arreglo de cribas, del tiemque con 5 min; el comportamiento en la recuperaCuadro 3, Efecta de ciertas modificaciones sabre el numero promedio de algunos nematodos fitoparasitos recuperados pOI la tecnica centrifugation-flotatiOn. Especie T.m.iio de muestra Numero de lav.dos Tiempo de suspension Ar(eglo de Crib.s... Tiempo de CentriGraved.despecffic. de (ml) (s) fug.cion (min) de la nem.todo solution .zucar.d. 50 100 150 1 2 3 20\" 40\"' 60\"' ABC 3' 4' 5' 1.12 1.15 1,18 C-PZ 25... 25. 32. 21. 22. 21. 12. 12. 12. 12. lOa 11. Sa 8. Sa 9. 10. 12. H-SA 2891 200b 148b 577. 73Oa 758. 549b 751.b 854. 647. 823. 8641 652.b 863. 554b 119b 845. 798. He-ZAR 5Sa 461 421 123. 124. 128. 147. 143. 113. 257. 172b 202lb 143. 116b 961 119. 111. 117. Tr-ZAR 3. 4. 7. 10. lOa 11. 7b 13. 11.b 8. 10. Sa 9. 7. 7. 7. 7. 9. Rr-O 1268. 1219. 624. 1040. 128Oa 1520. 1830. 1848. 168Sa 1163. 1290.1290. 787. 10421 613. 1220. 1059. 1117. . C-PZ (Criconemella sp. de P.lmir. de Zarcero); H-SA (Helicotylenc