Universidad De Oriente Research Articles

Evaluación del tratamiento anaerobio de las aguas residuales de una comunidad universitaria

<p>En las universidades cubanas más del 65 % de los estudiantes son becarios y se presta especial atención a la gestión de las aguas domésticas generadas en las comunidades y residencias universitarias. Este trabajo presenta la remoción de la materia orgánica en las aguas domésticas de la comunidad universitaria Antonio Maceo de la Universidad de Oriente empleando, a escala de laboratorio, dos sistemas: reactor UASB y laguna anaerobia. Los sistemas anaerobios evaluados, alcanzaron una remoción de la DQO superior al 70 % y una disminución de las bacterias coliformes totales desde 72x10 5 NMP/100 mL hasta 16 NMP/100 mL. La clarificación con alumbre mejora las características estéticas del efluente. Cualquiera de las variantes (UASB o laguna anaerobia) pueden ser aplicadas para la remoción de la materia orgánica en las aguas domésticas de la comunidad universitaria.</p>

Herramienta informática para la gestión de la calidad del posgrado

Abstract: Within the learning processes of relevance and impact that respond to social demands is the process postgraduate. In order to assess the quality of that process a group of indicators are set. Obtaining these indicators is done manually Universidad de Oriente. So a data store for calculating them is built, making obtaining reports and allowing to perform historical analysis of a large body of stored information, enabling timely decision making.
 Index Terms: Management, quality, postgraduate, indicators, data warehouse

PRIMER HALLAZGO DE APIOMITHRAX VIOLACEUS (A. MILNE-EDWARDS) (BRACHYURA: EPIALTIDAE: PISINAE) PARA EL CARIBE

Up to now, the sub-family Pisinae Dana, 1851 was represented in the Caribbean coasts of Venezuela by six species [Chorinus heros (Herbst, 1790); Libinia ferreirae Brito Capello, 1871; Herbstia depressa Stimpson, 1870; Sphenocarcinus corrosus A. Milne-Edwards, 1878; Pelia mutica (Gibbes, 1850) and Nibilia antilocapra (Stimpson, 1871)], which make up 38 % of the Pisinae crabs reported for the Caribbean Sea. During an examination of unidentified material from the crustacean collection of the Laboratory of Carcinology at Universidad de Oriente, Margarita Island, Venezuela, nine specimens (six males and three females) of Apiomithrax violaceus (A. Milne-Edwards, 1868) were discovered. Until now the distribution of this Pisinae species was known to range from Mauritania to Angola in the eastern Atlantic, Ascension Island in the central Atlantic, as well as Brazil and Orinoco Delta in the western Atlantic. All specimens were collected in Venezuelan waters, at the following locations: Margarita island: Playa Valdés, Península de Macanao, Boca Chica, El Maguey; Sucre State (mainland): Guayacán. This is the most northerly record of the species and it is the first time to be reported for the Caribbean Sea, increasing the number of known species of Pisinae to 17 in this area.

List of marine crabs (Decapoda: Anomura and Brachyura) of shallow littoral of Santiago de Cuba, Cuba

Marine crustaceans constitute one of the best studied groups in the Cuban waters. However, the level of systematic knowledge about them differs among the ecoregions of the platform. This paper presents the systematic list of hermit, porcelain and brachyuran crabs of the coast of Santiago de Cuba, on the southeast platform of Cuba. The records of the species have been compiled between 2009 and 2013, in ten locations, which differ in the type of habitats. Additional material was examined in the collection of the Universidad de Oriente Museum Charles Ramsdem. Eighty-one species are represented (seven hermits, eight porcelains and sixty-six true crabs). Data on their local and global distribution, their habitat, and notes on their reproductive period and fishing use are also provided.

Conocimiento docente sobre evaluación de los aprendizajes y su aplicación en la práctica de evaluación en los centros escolares públicos de Educación Básica en la Zona Oriental

<p>El estudio realizado por la Universidad de Oriente, a través del convenio con el MINED (Ministerio de Educación), tuvo como objetivo determinar si el conocimiento que tiene el docente sobre evaluación de los aprendizajes, influye en las prácticas de esta naturaleza que él realiza. La metodología utilizada para recabar la información fue de tipo cuantitativa, descriptiva y correlacional.</p><p>Los resultados confirmaron que la funcionalidad y los agentes de la evaluación; así como la evaluación por competencias, influyen y promueven la aplicación de esta en los centros escolares públicos. Por ello, el proceso pedagógico no se puede concebir sin la evaluación del aprendizaje. Si se imparte un contenido, la forma más efectiva de saber cómo ha llegado el conocimiento a los estudiantes es a través de la evaluación, en cualquiera de sus formas posibles, (exámenes tradicionales, pruebas objetivas u otros).</p><p>Conocimiento Educactivo, Vol. 2, 2015: 95-102</p>

2. Autoconcepto y sentido de vida en universitarios con diversidad funcional motora

El artículo reporta los hallazgos de un estudio cualitativo que tuvo como propósito valorar el autoconcepto y el sentido de vida de estudiantes con diversidad funcional motora en la Extensión Anaco de la Universidad de Oriente. Desde el apoyo del método fenomenológico, se realizaron entrevistas profundas a cuatro informantes claves. Los hallazgos se describen a partir de la triangulación de datos y de teorías, lo que muestra que existen algunas dimensiones de autoconcepto en función de la presencia o no de diversidad y el sentido de vida entre los géneros. La presencia de la diversidad funcional parece asociada con un nivel más bajo de autoconcepto académico y emocional para el género femenino en oposición al género masculino. Existe la necesidad de integrar alguna asesoría psicológica que facilite los procesos de crecimiento personal y fomenten la estabilidad psicológica de estas personas, pues pareciera que ellas y ellos no cuentan con ese apoyo en la institución.

English Language Skills Training: Theory and Practice-A Cuban Perspective

The ability to teach foreign languages effectively has become an increasingly important skill to develop and improve the language proficiency of students. Teachers need to develop and apply proactive and positive attitudes to foster new levels of foreign language learning within their students. Teaching, on its own, is not a panacea for success. This paper investigates how teachers at the Universidad de Oriente (UO) in Santiago de Cuba search for and apply innovative ways of teaching foreign languages to their students within current boundaries. The results from this research show that there is a positive relationship between the level of proficiency in a foreign language and the methods and approaches teachers apply to keep students motivated and interested in the subject matter. The literature review from this study provided supportive evidence which was strengthened with insights from face to face interviews and a focus group meeting. The outcomes confirmed that students, who are exposed regularly to practical and diverse teaching methods, are more likely to exceed the expected foreign language proficiency levels set by the UO’s quality standards.

The Value of Social Psychology: Working with Local Communities in Santiago de Cuba in 2012

It is recognized by academics and the community of practice that social psychology plays an important role in the everyday life of people, both at individual and at local community level. Recent social psychological research expresses the need to develop a better understanding of what good and effective social support for people looks like. This research report presents the outcomes of a field study by students from the Psychology Stream of the Faculty of Social Sciences of the Universidad de Oriente in Santiago de Cuba. A combination of literature review, face to face interviews and focus group meetings was applied to complete the research objectives. A number of specific approaches were identified as being most important to help members of local communities in Santiago de Cuba to resolve some of their social problems. The results suggest that members of local communities in Santiago de Cuba would benefit from adopting these approaches so they become more self-sufficient and self-confident in addressing their social issues. The findings also suggest that the management and control of emotions can play a vital role in enhancing creativity in people to find solutions to their social problems within the communities of this research. The results suggest that similar outcomes could be achieved in other communities within Cuba.

Just How Radical is President Nicolás Maduro

Click to increase image sizeClick to decrease image size Additional informationNotes on contributorsSteve EllnerSteve Ellner, professor of economic history at the Universidad de Oriente, Venezuela, is the coordinator of “Latin America’s Radical Left in Power: Complexities and Challenges in the Twenty-First Century,” published in the May issue of Latin American Perspectives.

Densidad de siembra para la producción de semillas de ocumo blanco (Xanthosoma sagittifolium (L.) Schott) en la Estación Experimental Hortícola San Agustín de la localidad La Guanota del municipio Caripe, estado Monagas, Venezuela

Se planteó evaluar la densidad de siembra para la producción de semillas de ocumo blanco (Xanthosoma sagittifolium (L.) Schott) bajo condiciones agroecológicas en La Guanota, Caripe en Monagas, Venezuela. Para llevar a cabo el planteamiento, el trabajo fue desarrollado en la Estación Experimental Hortícola San Agustín de la Universidad de Oriente, ubicada a 10º 12’ 46’’ LN y 63º 31’ 33’’ LO y a 1 400 m s. n. m., con temperaturas entre 23,5 ºC (máxima) y 10,5 ºC (mínima). Se evaluaron las distancias entre plantas (DEP) y entre hile­ras (DEH) de 0,8 m, 1 m y 1,2 m. El diseño estadístico fue bloques al azar en arreglo factorial con cuatro repeticiones; como resultado, las plantas madres manifestaron las típicas etapas de crecimiento: establecimiento, desarrollo y madurez. Finalmente, las distancias de siembra evaluadas no influyeron sobre el número de hijos/planta, sin embargo, la DEP de 1,2 m promovió mayor peso de los hijos, y mayor número y peso de los cormelos comerciales en sus combinaciones con las tres DEH.

Inventory of ascidians (Tunicata, Ascidiacea) from the National Park La Restinga, Isla Margarita, Venezuela

Although ascidians form a conspicuous part of sessile assemblages in the Caribbean, no specialized inventories have been developed in Venezuela, except for a list of 15 species reported from Margarita Island (1984). Here we present the results of a taxonomic workshop held in the Universidad de Oriente, Boca del Rio, Margarita Island during April 20-25 of 2009, sponsored by the NaGISA-Caribbean Sea program. La Restinga National park was surveyed and we found 29 species belonging to 19 genera and 10 families. The most abundant colonial species were Clavelina oblonga, Aplidium accarense, Polyclinum constellatum, Distaplia bermudensis, Symplegma rubra, S. brakenhielmi, Botrylloides nigrum and Ecteinascidia turbinata. Among the solitary ascidians Phallusia nigra, Ascidia curvata, Microcosmus exasperatus, Styela canopus, Styela sp.1 and Styela sp. 2 were the most abundant. The ascidian diversity in this lagoon is one of the highest for similar habitats in the Caribbean and seven species are new registers for Venezuela (Ascidia curvata, Ecteinascidia styeloides, Aplidium accarense, Distaplia stylifera, Trididemnum orbiculatum, Symplegma rubra, and S. brakenhielmi). One point of concern for the conservation of la Restinga National Park is the presence of possible introduced species, and some management procedures are suggested.

Régimen político y calidad de las leyes en Cuba

Numero 128 Mayo - Agosto 2010 ISSN 0041 8633 REGIMEN POLITICO Y CALIDAD DE LAS LEYES EN CUBA * POLITICAL REGIME AND QUALITY OF LAWS IN CUBA C. Yoel CARRILLO GARCIA ** The objective of this work is to identify the main causes that, from the institutional, normative, theoretical and methodological point of view, affect the quality of the laws in Cuba. After a general description of the political regime established in the Constitution of 1976 are used the analytic instruments developed by the theory and the technique of the legislation in the last thirty years and it´s antecedents in the XVIII and XIX centuries. Related with the conclusions obtained, a group of recommendations are formulated, considering that they could contribute to improve the quality of the laws in Cuba, in the author´s opinion. Descriptors: cuban political regime, electoral system, quality of the laws, legislative process, legislative procedure. * Articulo recibido el 22 de octubre de 2009 y aceptado para publicacion el 22 de enero de 2010. ** Universidad de Oriente, Santiago de Cuba. * Nota: Debido que la traduccion es automatica podra ser inexacta o contener errores.

Analysis of bibliographic references in Zootecnia Tropical

PurposeThe purpose of this paper is to analyze the bibliographic references contained in the scientific papers (articles and technical notes) published from 1985 to 2005 in Zootecnia Tropical (ZT), a scientific journal.Design/methodology/approachA retrospective descriptive study is conducted using one‐dimensional bibliometric indicators such as: output, bibliographic density, institutional affiliation, recentness of the documents cited, document typology, self‐citations and scientific collaboration. Univariate descriptive analysis is used to study the indicators.FindingsA total of 349 scientific papers (300 articles and 49 technical notes) are reviewed; output ranged from a maximum of 34 papers in 2001 to a minimum of four in 1990, with a mean of 15 papers per volume. The papers analyzed contain a total of 5,651 bibliographic references, with an average of 19 ± 9 references per paper; the largest number of references (19 ± 33) are found in the articles and the smallest (10.5 ± 13) in the notes. Venezuelan institutions account for 89 per cent of the papers and international institutions for the remain in 11 per cent; of the Venezuelan institutions, most (62 per cent) are National Institute of Agricultural Research (INIA) bodies and the rest universities and other organizations, especially the Universidad Central de Venezuela (UCV) and Universidad de Oriente (UDO). Universities are also among the most frequent international contributors, most prominently Marianga State University in Brazil and Tucumán National University in Argentina. Around 60 per cent of the references were more than ten years old when they were cited; 21 per cent were between five and ten years old and 19 per cent less than five years old. Journal articles, with 57 per cent, are the document type most frequently cited, followed by books, with 23 per cent; the rest consisted in postgraduate theses (3 per cent), undergraduate theses (2 per cent) and congress, conference and seminar proceedings (12 per cent). The self‐citation or endogamy rate in the journal is 4 per cent. Over half (53 per cent) of the papers are written by authors with the same affiliation. Inter‐institutional papers account for the remaining 47 per cent, with 34 per cent involving national collaboration, particularly between the INIA and the UCV; international co‐authorship comes to 13 per cent, primarily involving Brazilian and Argentine universities.Originality/valueThis paper analyzes the use of information in the Venezuelan scientific community from the vantage of a specific journal, ZT. These studies constitute useful and objective tools for evaluating scientific activity.

Molecular phylogenetic analyses of mullets (Mugilidae, Mugiliformes) based on two mitochondrial genes

Escuela de Ciencias Aplicadas del Mar, Universidad de Oriente, Isla de Margarita,VenezuelaSummaryMolecular phylogenetic studies are very scarce for the Mugil-idae family; the present analysis using DNA sequences of themitochondrial 16S rRNA and cytochrome b genes is the firststudy involving Brazilian mugilids. The results corroborate themonophyly of Mugil and are elucidative for the taxonomy ofBrazilian mugilids. Mugil curema is clearly divided into twogenetically distinct taxa, M. curema type I being closer relatedto Mugil hospes and the true M. curema (type II) groupingsignificantly with M. incilis. The results also suggest that Mugilliza and Mugil platanus should be treated as a single species oreven populations of Mugil cephalus.IntroductionMugilids are coastal marine, brackish water and freshwaterfishes, distributed worldwide in tropical and temperate seas,migrating offshore to spawn. Mullets are very importantcommercial species and are highly exploited throughout theirdistribution (Cervigo´n, 1993; Cervigo´n et al., 1993). They arepopularly known in Brazil as tainha, parati, curima˜, cai´ca andpratiqueira (Menezes, 1983; Menezes and Figueiredo, 1985).The most recent taxonomic revision (Thomson, 1997) recog-nizes 14 genera and 64 valid species, Mugil being the only oneoccurring in the Atlantic coastal waters of Brazil. The numberof mugilid species reported for the northern coast of SouthAmerica, including the entire Brazilian coast, varies between 7and 8 (Cervigo´n et al., 1993; Thomson, 1997; Menezes et al.,2003). The discrepancies are related to Mugil hospes,M. cephalus, M. platanus and the suppressed name ofM. gaimardianus.Accurate species identification is the first step in eachsuccessful conservation and fisheries management program(Ludwig, 2006). Identification of mugilid species is problem-atic, especially in juvenile stages, because of their highlyconserved external morphology and the paucity of usefultaxonomic characters (Menezes, 1983; Menezes and Figuei-redo, 1985; Cervigo´n, 1993; Thomson, 1997) and homo-geneous karyological structure. The majority of species showsa diploid number of 48 chromosomes (Cataudella et al., 1974;Delgado et al., 1992; Jorda˜o et al., 1992; Crosetti et al., 1993;Rossi et al., 1996, 1997; Nirchio et al., 2001, 2003), except forM. curema which has a diploid number of 24 or 28 (Le GrandeandFitzsimons,1976;Nirchio et al.,2003,2005),andM.incilispresenting 2n = 28 (Galetti et al., 2000).Because of the economic importance of this fish family it isessential to improve the current identification keys and takeadvantage of the powerful molecular markers now available.Mitochondrial DNA has been widely used in fish taxonomybut only a few Mediterranean mugilid taxa have so far beensubjected to molecular phylogenetic analysis. Caldara et al.(1996) used the mitochondrial cytochrome b and 12S rRNAgenes to evaluate the phylogenetic relationships among Chelon,Oedalechilus, Liza and Mugil. According to these authors,based on DNA sequences the arrangement produced was verydifferent from the current taxonomy based on morphology.Nuclear data of allozymes and mitochondrial 16S rDNAsequences (Rossi et al., 2004) suggest that the Mediterraneanspecies of Liza do not form a monophyletic group, inagreement with the previous results of Caldara et al. (1996).The present phylogenetic analysis based on the 16S rRNAand cytochrome b mitochondrial genes is the first for Brazilianmugilids (Western Atlantic), and includes previously studiedMediterranean taxa (Mugil, Chelon and Oedalechilus). Thephylogenetic trees depicted from both genes are congruent andsurprisingly reveal two possible species morphologically iden-tified as Mugil curema, but clearly distinguished by the DNAanalyses. Molecular data also suggest that Mugil liza andMugil platanus should be treated as a single species or possiblypopulations of Mugil cephalus.Materials and methods

New Records of Desmopachria tarda Spangler (Coleoptera: Dytiscidae), an Endemic Species from Cuba, with Habitat Notes

Departamento de Biologi´a, Facultad de Ciencias Naturales, Universidad de Oriente. Ave. PatricioLumumba s/n, Santiago de Cuba, Cuba. CP:90500e-mail: adeler1982@yahoo.com; ysuarez@cnt.uo.edu.cuThe predaceous water beetles of the genus Desmopachria Babington are small dytiscids ranging fromabout 1.1 to 3.0 mm in length (Young, 1980; Larson et al., 2000; Miller, 2001, 2005). The genus comprisesof 92 species widely distributed in America (Nilsson, 2001), but by far most diverse in the NeotropicalRegion with 87 species. Four species of Desmopachria are found in Cuba (Desmopachria aspera Young, D.darlingtoni Young, D. glabella Young and D. tarda Spangler) of which two, D. glabella and D. tarda areendemic (Young, 1980; Spangler, 1981; Peck, 2005).Desmopachria tarda was described and reported from Cabezada del Ri´o Indio, Gran Piedra, Santiago deCuba from 1000 m.a.s.l. This species shows slower swimming ability compared to other members of thisgenus (Spangler, 1973). This small dytiscid is distinguished from all other species of Desmopachria by itsovate and moderately convex body form, length (1.65 mm) and dark reddish regions on the base of thehead, on the pronotum and along elytral suture.The specimens reported here are the second records of D. tarda from Cuba but are collected from twonews localities. New records: Cuba: Santiago de Cuba: Gran Piedra, El Olimpo, stream, 21 Km east ofSantiago de Cuba, 750 m.a.s.l, 03-VIII-2005, A. Deler-Herna´ndez coll. 15 specimens, 04-VIII-2005, A.Deler-Herna´ndez coll. 18 specimens; Dos Palmas, Nacimiento del Ri´o Cauto, stream, 45 km northwesternof Santiago de Cuba, 450 m.a.s.l, 01-XII-2005, Y. S. Megna coll. 4 specimens.Specimens were collected using an aquatic net of 30 cm in each side, 40 cm of bottom and mesh size 50.5 mm. The substrates were vigorously swept with the net for several minutes. Specimens will be depositedin the Museum of Natural History Charles T. Ramsden de la Torre (CZCTR) of the Universidad de Oriente.The two new localities are in the Sierra Maestra, but in different drainage systems. El Olimpo is 8 kmfrom the type locality on the south slope of the Cordillera La Gran Piedra and the Nacimiento del Ri´oCauto is 70 km to the west in the Cordillera del Turquino.The specimens were collected in the backwaters of freshwater habitats with clear waters, muddy-stonybottom, located in highlands with a low exposure to sun, without aquatic vegetation and with abundantcover vegetation. Prevalence of D. tarda in this pristine habitat would suggest that this species representsa good bioindicador of mountainous freshwater ecosystems. Ribera and Foster (1992) and Sa´nchez-Ferna´ndez et al. (2004) consider freshwater aquatic beetles to have great utility to determine the degree ofconservation of the habitats. Also, the following water beetles were collected in El Olimpo and Nacimientodel Rio Cauto: Gyrinidae: Dineutus longimanus Olivier, Dytiscidae: Laccophilus bifasciatus Chevrolat,Laccophilus venustus Chevrolat, Copelatus insolitus Chevrolat and Copelatus posticatus (Frabricius). Allthese species are rather represented in springs or mountain streams (Megna and Deler, 2006; Deler-Herna´ndez et al., (in press). Although, L. venustus and C. posticatus are generalists and with widerdistribution (Spangler, 1981; Peck, 2005).We thank Patricia L. M. Torres (Universidad de Buenos Aires), Y. Alarie (Laurentian University), B.Reyes-Tur and D. Rosabal (Universidad de Oriente) for their critical review of the manuscript andvaluable comments.Literature CitedDeler-Herna´ndez, A., Y. S. Megna, D. Gonza´lez-Lazo, and C. N. Carcase´s (in press). Insectos acua´ticos ya´reas prioritarias para la conservacio´n en la cuenca alta del ri´o Cauto (Santiago de Cuba, Cuba).Boleti´n Sociedad Entomolo´gica Aragonesa.

CARACTERIZACIÓN DEL PERFIL MOTIVACIONAL DEL ESTUDIANTE DE INGRESO A LA CARRERA DE TURISMO Y HOTELERÍA, UNIVERSIDAD DE ORIENTE, NÚCLEO NUEVA ESPARTA: AÑO 2001

The profile and perceptions of the student, himself and the environment, understanding this, as all the factors that motivate the election of a tourism carrier, compromise with it and persevere in finishing it at the Hotel and Tourism School of the Universidad de Oriente, first period of 2001, is characterized. A descriptive study and field research using a survey technique was done. A socio/demographic, academic and motivational characterization was done, as conclusion there is an information and guidance need for the students.

From the Editor

Cuban-American Aurelio de la Vega has been one of the most daring and innovative Latin American composers of his generation. He first studied music at the Instituto Musical Ada Iglesias in Havana under Harold Gramatges. While in Los Angeles as cultural attaché to the Cuban consulate he took private composition lessons with Ernst Toch. From 1953 to 1959 he directed the music department at the Universidad de Oriente in [End Page 1] Santiago de Cuba. He then settled in California where he taught composition and founded the electronic music studio at the California State University, Northridge (formerly the San Fernando Valley State College). He retired from that institution in 1994 as Distinguished Emeritus Professor after over thirty years of instructional activities.

Cognitive conflict as a teaching strategy in solving chemistry problems: A dialectic–constructivist perspective

AbstractThe main objective of this study was to evaluate the effect of teaching experiments within a dialectic‐constructivist framework based on the following considerations: (a) Cognitive conflicts used in the teaching experiments must be based on problem‐solving strategies that students find relatively convincing: (b) after having generated a cognitive conflict, it is essential that the students be provided with an experience that could facilitate the resolution of the conflict; and (c) the teaching strategy developed is used by an interactive constructivist approach within an intact classroom. The study was based on two sections of freshman students who had registered for Chemistry I at the Universidad de Oriente, Venezuela. One of the sections was randomly designated as the control group and the other as the experimental group. To introduce cognitive conflict, the experimental group was exposed to two teaching experiments dealing with stoichiometry problems based on the concept of limiting reagent. Students in the control group were exposed to the same problems—however, without the cognitive conflict teaching experiments format. To evaluate the effect of the teaching experiments, both groups were evaluated on five different problems at different intervals during the semester, referred to as posttests. All posttests formed part of the regular evaluation of the students. Results obtained show the advantage of the experimental group on four of the posttests. It is concluded that the experimental treatment was effective in improving performance on the immediate posttests. It was observed that some students protect their core belief [see Lakatos, I. (1970). Falsification and the methodology of scientific research programmes. In I. Lakatos & A. Musgrave (Eds.), Criticism and the growth of knowledge (pp. 91–196). Cambridge: Cambridge University Press] in stoichiometry (establishing equivalent relations between different elements or compounds) by ignoring the conflicting data, just as conflicting (anomalous) data do not necessarily convince a scientist to abandon a particular theory.

Relationship between student performance on conceptual and computational problems of chemical equilibrium

The main objective of this study is to compare student performance on problems requiring conceptual understanding or the use of algorithmic solution strategies, that is, computational problems. Seventy‐eight science major freshman students at the Universidad de Oriente (Venezuela) were tested to obtain information on various aspects of chemical equilibrium. Results obtained support the hypothesis that students who perform better on problems requiring conceptual understanding also perform significantly better on problems requiring manipulation of the data, that is, computational problems. If, in order to formulate physical theories, scientists generally follow the sequence: manipulation of the data —> conceptual understanding (cf. Hanson 1958: ‘conceptual gestalt'), it is suggested that solving computational problems before problems requiring conceptual understanding would be more conducive to learning, that is, the quantitative precedes the qualitative. Finally, this study has identified difficulties stud...

POLYCULTURE EXPERIMENTS OF POMPANO Trachinotus carolinus (CARANGIDAE) AND SPOTTED RED SHRIMP Penaeus brasiliensis (PENAEIDAE) IN CONCRETE PONDS, MARGARITA ISLAND, VENEZUELA

ABSTRACTSince 1978, polyculture experiments of pompano (Trachinotus carolinus) and shrimp have been conducted in the Centro de Investigaciones Científicas, Universidad de Oriente, Venezuela. Experiments are carried out in circular concrete ponds (28 m2) with running seawater (salinity 37–39 ppt and temperature 26.4–30.9°C) and constant aeration. In the first experiment (September‐December 1978) pompano and shrimp were stocked at a density of 10/m2 and were fed with Tivela mactroides (Mollusca, Pelecipoda) “guacuco” pellet of 60% crude protein. Pompano 0.22±0.1 g reached after 75 days 40.6±25.6 g with food conversion of 6.59 and 17.14% survival; shrimp 1.3±0.4 g reached a weight of 5.7±0.9 g and 2.68% survival during 75 days. The common food conversion was 7.57.The second experiment (June‐August 1981) was carried out in tanks with a false bottom. Pompano and shrimp were stocked at densities of 5 and 10/m2 respectively, and were fed with a pellet named GSCA (42.8% crude protein). Pompano 4.0±1.1 g reached 62.1±10.3 g after 75 days of culture, the food conversion and survival being 3.1 and 64.29%, respectively. Shrimp stocked at 3.6±0.6 g reached 8.9±1.8 g after 75 days, and feed conversion was 10.7 with 54% survival. The common feed conversion for pompano and shrimp was 6.6. After 75 days of culture the high mortality of pompano was due to the infection of branchial parasites, the protozoa Amyloodinium ocellatum and the trematode Bicotylophora trachinoti.