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El artículo presenta detalles sobre actividades patrocinadas por el Centro de Estudios Monetarios Latinoamericanos (CEMLA). Representantes decidieron encargar un catálogo de maquinaria para los bancos centrales durante la Tercera Reunión Operativa del CEMLA. Un comité designado por CEMLA laboró sobre la clasificación de las máquinas y equipos utilizados por los bancos. El artículo ofrece detalles sobre las decisiones del comité.

Se presentan noticias que tratan de la economía internacional. El Fondo Especial de la Organización de las Naciones Unidas tropezaba con una aguda escasez de recursos financieros. La economía de Europa Occidental entraba en una fase de auge. Se habla del consumo mundial de papel y sus derivados.

Thirty species of Inoperculate Discomycetes are described herein from the Nahuel Huapí National Park (Argentina), distributed among thirteen genera belonging to the following families: Hyaloscyphaceae, Dermataceae, Sclerotiniaceae y Helotiaceae. Three of them, namely, Calloria, Sphagnicola and Phaeohelotium are recorded for the first time for Argentina. Of the thirty species found, fifteen are new records for this country. The following new combinations are proposed: Cyathicula chlorosplenioides (Speg.) Gamundí (basinym: Helotium chlorosplenioides Speg.); Rutstroemia megalospora (Speg.) Gam. (bas.: Helotium megalosporum Speg.) y Rutstroemia microsperma (Speg.) Gamundí (bas.: Helotium microspermum Speg.). The paper contains a critical study of type material from Spegazzini's herbarium, and the description of a new species of the same general area: Phaeohelotium castaneum. [ABSTRACT FROM AUTHOR]

This is the first from a series of papers dealing with the comparative study of all neotropical species of Salvinia. In the first part, the author comments the systematic position of all the species mentioned so far for tropical America. In the second part, the morphology and structure of the sporophyte and its reproductive organs of Salvinia oblongifolia are studied. This species lives in the center-north and NE of Brazil. [ABSTRACT FROM AUTHOR]

In the present paper, the second of the series with started with a study of the sporophyte of S. oblongifolia, the author repords some dates and adds comments of the following aspects of S. auriculata: leaf dimorphism, venation, experiments of decapitation of the submerged organs and the lateral branches; leaf anatomy with the special emphasis on the development air chambers and hair and papilla formation; ramificación of the submerged organs and its significance for the identification of S. auriculata and related species [ABSTRACT FROM AUTHOR]

In the present paper, the author describes a new species of Salvinia, S. herzogii, on Argentine material from Lower Paraná River. It is probable that all specimens of this country determined S. auriculata Aublet, belong to this new species. A key for identification of S. herzogii and related species according to the leaf characters and configuration of the submerged organs is given. [ABSTRACT FROM AUTHOR]

In the present paper, the fourth of the series which started with a study of the sporophyte of Salvinia oblongifolia, the author reports some data on the following aspects of S. rotundifolia: anatomy of the rhizome and submerged organ. Comparative data on its related species, S. herzogii, are given. [ABSTRACT FROM AUTHOR]

El artículo presenta noticias que tratan de la economía latinoamericana. Se informa sobre una comisión colombo-ecuatoriana que estudia las posibilidades de integración de las zonas fronterizas de ambos países. Se anuncia que Chile es uno de los grandes exportadores de papel. Se habla de un remanente de 300.000 toneladas de trigo que tiene Uruguay para exportación.

In this short paper, the author reports the presence of Notholaena sulphurea (Cav.) J. Sm. in NW and W Argentina (Jujuy and La Rioja Provinces). A key for the Argentine species of that genus, is also given. [ABSTRACT FROM AUTHOR]

Data editing by a computer program can be regarded as a form of statistical quality control. In that perspective, costs and benefits of alternative programs can be compared to one another and, of course, to no control plan at all. This paper outlines one approach to cost-benefit comparison and utilizes a realistic example to suggest that computerized data editing is generally superior to clerical editing. It also warns against edit programs which provide for record rejections and off-line review. Most importantly, it urges that a systematic comparison of costs can assist significantly in edit planning. [ABSTRACT FROM AUTHOR]

Several approximations to the binomial distribution were compared in 1956 by Raft [9], including the normal, arcsine, normal Gram-Charlier, Camp-Paulson, Poisson, and Poisson Gram-Charlier approximations. The closeness of these approximations is judged by the maximal error which can arise in evaluating any sum of consecutive binomial terms. Borges [3] investigated a general class of approximations (which includes some of the above) and showed that a certain beta-transformation of a binomially distributed variable is the unique member of this class which is approximately normal with error 0(l/n). In 1963, Bol'shev [2] gave two new Poisson-type approximations. In this paper, some of Raft's tables are extended and tables for the error of these newer approximations are added. As a consequence of the numerical results obtained, the Poisson Gram-Charlier approximation is recommended for small values of p while the Camp-Paulson and Borges' approximations should generally be preferred for large p. [ABSTRACT FROM AUTHOR]

In the first part of this paper, the author gives basic information on the physiography, climate and vegetation of the studied area, which is located in the northwestern corner of Argentina and covers the provinces of Jujuy, Salta, Catamarca, Tucumán and partially, Santiago del Estero and La Rioja. Also, in that general part, comments are made on the level of the local knowledge of the Pteridophytes. In the subsequent chapters, the author offers a key of families and the revision of Lycopodiaceas, Selagnellaceae, Equisetaceae, Psilotaceae, Ophioglossaceae, Schizaeaceae, Hymenophyllaceae, Cyatheaceae, Dennstaedtiaceae and Adianlaceae (according to Alston's classfication of the leptosporangiate ferns), with a total of 25 genera and 77 species. Under each taxon, the synonymy, types, relationships, cited specimens, distribution patterns and ecological information are given. Three new species are described: Hymenophyllum (Sphaerocionium) capurroi, Cheilanthes volcanensis and Pleris famatinensis and the following combinations are proposed: Adiantum thalictroides var. hirsutum (Hook & Grev.) and Pleris inermis (Rosenst.). Maps, graphs and illustrations of the new taxa are also given. [ABSTRACT FROM AUTHOR]

In this third paper dealing with the algae of Brazil, four Chlorophycophyta and six Chrysophycophyta are described. These organism were found in the so called "Sete Lagoas" Lake-District, State of Minas Gerais. They are: Granulochloris maxima nov. sp., Pseudoquadrigula lagoensis nov. gen., nov. sp., Oedogonium spirostriatum, Pseudochaete crassisetum (Chlorophvceae), Phalansterium digitatum (Chrysophyceae), Tetraedriella polychloris, T. acuta, Goniochloris gigas, Peroniella minuta y Pseudostaurastrum enorme (Xanthophyceae). Except Oedogonium, all these genera are mentioned for the first time for Brazil and also for South America. [ABSTRACT FROM AUTHOR]

This paper deals with a taxonomic study of Cyanophyta epiphytic on submerged plants in the following ponds: Chascomús, El Burro, Yalea and Vitel. Keys are given for the identification of the 3 orders, 5 families, 11 enera and 24 species found. The taxa are described and the species illustrated. Eigth species are described for the first time for Argentina. [ABSTRACT FROM AUTHOR]

In this paper, the author studies the following families of ferns, which are growing in the northwestern area of his country: Marsileaceae (Marsilea, 1 or 3 species), Salviniaceae (Salvinia, 1 species) and Azollaceae (Azolla, 2 species). One new taxon is described and illustrated: Marsilea punae. Under each taxa, the synonymy, affinities, critical data and geographic distribution, including the studied specimens, are given. [ABSTRACT FROM AUTHOR]

This paper deals with the taxonomic study of soil algae in the surroundings of Buenos Aires (Argentina). Sixty-five species are studied. They belong to sixteen genera of Cyanophyceae distributed in five families and two Orders, and twenty genera of Chlorophyceae distributed in twelve families and six Orders. Among Cyanophyceae the family Oscillatoriaceae is the best represented with six genera and twenty species; among the Chlorophyceae, the Chlorococcaceae with six genera and eight species. The species Phormidium frigidum, Ph. subtruncatum, Ph. rubriterricola, Ph. papy raceum, Hydrocoleum brebissoni, Anabaena fertilissima, Tolypothrix brevis, Plectonema gracillimum (Cyanophyceae) and Chlamydomonas gloeopara, Bracteococcus minor, B. giganteus, Chlorococcum pinguideum, Chlorella fusca var. fusca, Ch. saccharophila var. saccharophila, Ch. zofingensis, Ch. minutissima and Klebsormidium subtile (Chlorophyceae) are new records for Argentina, and so are the genera Coccomyxa, Klebsormidium and Pleurococcus (Chlorophyceae). They are described and the species illustrated. Keys are given for the identification of the orders, families, genera and species. [ABSTRACT FROM AUTHOR]

This paper is preliminar to a research on Fungal Succession on leaves of Austro-southamerican species of Nothofagus. Deals with some foliicolous Hyphomycetes and Ascomycetes, which are first recorded for Argentina and on N. dombeyi leaves, as Candelabrum spinulosum, Idriella lunata, Anungitea fragilis, Gyrothrix pedicelata, Cylindrocarpon tenue, Chalara brevipes, Ch. nothofagi, Ch. hughesii, Mirandina typica, Ulocladium atrum, Botrytis cinerea, and Gelasinospora reticulispora. A new combination, Polyscytalum fuegianum (Speg.) Gam. et all. and three new species, Triposporium foliicolum Gam. et all., Phialea nothofaginea Gam. et all. and Trochila tetraspora Müller et Gam. are proposed. Synonymy between Dyctiochaeta Speg. and Codinaea Maire is stablished. [ABSTRACT FROM AUTHOR]

This paper deals with the systematic study of the genera Calycorectes, Hexachlamys, Myrciaria, Paramyrciaria, Plinia and Siphoneugena, which represent the subtribe Eugeniinae Berg, in the Argentine flora The paper also present an enlargement of the area of distribution of Myrciaria tenella (DC.) Berg, which up to now has only been mentioned in the NW of Argentina. Paramyrciaria delicatula (DC.) Kausel is accepted instead of Myrciaria delicatula (DC) Berg, because this species has embryo with two plane-convex cotyledons and a circumcised, elongated hypanthium The new combination Plinta baporeti (Legrand) Rotman, is proposed for a species caracteristic of galleria forests The name Plinia trunciflora (Berg) Kausel has been accepted, in its author's true sense, for a species which up to now has only once been collected in Argentina. Descriptions and illustrations of every species of Hexachlamys, Siphoneugena and Calycorectes are given. Guapurium peruvianum Poir, remains as an entity of doubtful taxonomic position. It has been collected on many an opportunity, but its embryonic morphology is difficult to interprete because it shows polyembryos which, so far, have not allowed correct interpretation of this entity. [ABSTRACT FROM AUTHOR]

Senecio is one of the richest genera of Angiosperms in the world, specially in the mountainous regions. In this work 114 species are reported for Bolivia, this number may probably increase as the botanical exploration of its territory improves. As in previous papers by the author the genus has been treated following a conservative concept. Three sections are accepted for Bolivia; Aetheolaena (Cass.) Hoffm., Streptothamni Greenm. and Senecio, the last one containing ten Series (treated in previous works as Sections). The Sect. Aetheolaena is represented by three species and Sect Streptothamni by 18. The series included in the Sect. Senecio have the following numbers of species: Senecio (1); Wernerioides Cabr. (1), Hualtatini DC. (2), Culcitium (H.B K.) Cuatr. (6), Crassicephali Cabr. (6); Myriocephali (Cabr.) Cabr. (18), Otopteri Cabr. (7); Corymbosi Cabr. (29), Graveolentes Cabr. (2); and Suffruticosi Cabr. (21). The following are new taxa or new combinations Senecio comosus var. culcitioides (Sch Bip) nov. stat., S. zongoensis nov sp, S pampeanus f. serratus nov. form.; S. alniphilus nov. sp. and S clivicolus var pampae (Lingelsh.) nov. stat. [ABSTRACT FROM AUTHOR]

It is know that strains of E. C 01 with wild genotype for reparation. when are irradiated at temperature between 42°C and 45°C, shown an increase of radioresistance. At then given temperature the number of double strands breaks of DNA decrease. Some authors report that the radioresistance increased is due to the elevation of the irradiation temperature is related to the cell membrane status The present paper includes reports on the effects of increased temperature on the sensitivity -at gamma quantum- of Bacillus licheniformis RI 75-1 vegetative cells. Temperatures of 42°C and 60°C during irradiation were employed. An increased in radioresistance was found when the temperature of irradiation was increased to 42°C. However, a decrease in viability was observed. Heat treatment prior to irradiation showed an increase in the number of radioresistance colonies when compared. [ABSTRACT FROM AUTHOR]

This paper deals with the embryology of D. spinosa Ruiz et Pav.; the following are the main conclusions: A) Embryological conclusions: --Anther walls: Its development corresponds to an archaic form within the basic type of Davis (1966), in which there are three or four middle layers. The tapetum is of the secretory type and the endothecium cells develop U-form thickenings on the radial walls and internal tangential wall. --Microsporogenesis: There is a simultaneous formation of tetrahedral tetrads. --Ovule: It is anatropous, crassinucellate and has only one integument. The internal epidermis of the integument differentiates itself in an endothelium. At the moment of anthesis, transfer cells stem from the endothelium and underlying layers, in the micropilar region. --Growth of the pollen tube and fertilization: The growth of the pollen tubes starts in the epidermis of the stigma, going through the transmiting tissue of the style and ovary and finally, the secretory epidermis of the placenta and funicle. Several callose plugs are formed in its way. The fertilization is porogamous; the pollen tube discharges inside one of the synergids. --Endosperm: The development of the endosperm corresponds to cellular megatype, isopolar type, longitudinal subtype, i. e. 1211 according to the EODP system (Di Fulvio, 1983). At the beginning of the proembryo's globular phase, the cells of the micropylar and chalazal regions develops haustorial characteristics and do not contain reserve materials. These cells will be digested by the embryo during development and the same occurs with the cells of the central zone. The rest of the tissues, with food reserves identified as protein bodies, persists in the completeIy developed seed. --Episperm: It is derived from the external epidermis of the ovule and is represented by a layer of sclereids whose radial and internal tangential wall are thickened, lignified and profusely pitted. The external tangential walls formed by pectic compounds, are also thickened. Around the micropyle there is also a bundle of sclereids which have evenly thickened, lignified walls with numerous pits. The episperm is scarcely known in the Loganiaceae but, morphologically, the sclereid layer of D. spinosa resembles the one described in Fagraea. B) Taxonomical conclusions: As Loganiaceae s. 1. is one of the tropical families whose embryology is not very well known it is still premature to try to arrive to final conclusions. Nevertheless, the results obtained in this work indicate that: 1. The characteristics of cellular endospermogenesis and the presence of an endothelium would justify the separation of Desfontainia from Loganiaceae s. str. As regards the isopolar type of endospermogenesis, it coincides with Polypremum (Buddlejaceae) and Mitrasacme (Loganiaceae). The nature of the cellular endospermogenesis is different to Buddleja where only the micropylar cell contributes to the development of the storage tissue and the other cell forms 4 chalazal haustoria. On the other hand, the isopolar type of endospermogenesis and the presence of endothelium are characteristics of the families with cellular endosperm belonging to the order Solanales; for that reason Polypremum, Mitrasacme and Desfontainia are, probably, better referred to the Solanales rather than to the Gentianales or Scrophulariales. 2. As Desfontainia posseses many morphological differences with any of the families included by Cronquist in Solanales, it only could be incorporated in this order as an independent family. [ABSTRACT FROM AUTHOR]

This paper deals with the endosperm and episperm development of two species of Buddleja: B. stachyoides Chain. et Schldl. and B. tubiflora Benth. The following are the main conclusions: --The cellular development of the endosperm is --according to the EODP system (Di Fulvio, 1983; 1985)-- of the heteropolar type and longitudinal subtype (EODP 1221) with chalazal and micropylar primary haustoria. The cells near the primary haustoria differentiate, secondarily, as haustorial cells. --In the mature seed the endosperm is ruminate and corresponds to the Verbascum type of Periasamy. --The endothelium is differentiated at the time of the anthesis but its cells divide actively after fertilization only by means of anticlinal divisions; in this way, the number of cells around the endosperm remains constant since the anthesis until the seed development is completed. These cells keep pace with the endosperm expansion becoming considerably enlarged. --The episperm consists of only 2 layers, the endothelium and the outer epidermis. The outer epidermal cells develop U-like secondary lignified thickenings along the radial and inner tangential walls; the outer tangential wall is compressed. Cells with reticulated thickenings develop around the micropyle. --Preliminary phytochemical and morphological studies showed close affinities between Buddleja and some genera of the Scrophulariaceae. The present study emphasizes this relationship and suggests that Buddlejaceae should be considered as an independent family, to included in the order Scrophulariales. Moreover, the absence of embryological similarities with Loganiaceae is at the same time demonstrated. [ABSTRACT FROM AUTHOR]

The leaf alcoholic extracts of six native Argentine species of Vicia (subg. Vicilla, sect. Australis: V. gramineae, V. macrogramineae, V. epetiolaris, Y. montevidensis, V. nana and V. pampicola) and one adventitious species (subg. Vicia, sect. Vicia: V. sativa subsp. nigra) were studied by bidimentional paper chromatography. Eighty phenolic compounds were found in 107 individuals that were studied. In spite of the high intraspecific variability, observed in all the species, the chromatographic identification was possible because of the presence of specific compounds in each of them. Numerical taxonomy methods were applied to estimate the degree of similarity. The distance and association coeficients used generated congruent phenograms that showed seven main groups which agreed with the seven species that were studied and confirm the exomorphological classification. [ABSTRACT FROM AUTHOR]

This paper deals with two genera of Chrysophyceae, Mallomonopsis and Paraphysomonas new for Argentina. Mallomonopsis elliptica var. elliptica, M. parvula nov. comb., M. paxillata, and Paraphysomonas vestita are described and illustrated. [ABSTRACT FROM AUTHOR]

The method of periodate-permanganate oxidation was studied in this paper in order identify the distribution of tritium in a molecule of eicosatrienic acid obtained by catalytic hidrogenation of the acetilenic precursor with gasseous tritium. It was found that the inclusion of tritium in position 8, 9, 11, 12, 14 and 15 did not lead to isotopic effects during the enzymatic conversion of eicosatrienic acid into prostaglandins. A fast and simple method was proposed to determine the isotopic effects in enzymatic reactions. [ABSTRACT FROM AUTHOR]

In the present paper Johannesbaptistia pellucida (Dickie) W. R. Taylor & Drouet is studied. Description and illustrations as well as ecological observations are added Johannesbaptistia whitfordii Thomas & Gonzalves is considered a synonim of J pellucida. [ABSTRACT FROM AUTHOR]

In the present paper Fischerella major Gomont from Tierra del Fuego, Argentina, is studied. Description and illustrations as well as ecological observations are given. [ABSTRACT FROM AUTHOR]

This paper deals with the response of Ambrosia tenuifolia and other species of the Salado Basin grasslands to a long flood period. The following are the main conclusions: 1) Ambrosia tenuifolia and others dictoyledonous species do not tolerate floods of large duration such as the one occurred in 1978 in the Salado Basin. 2) Grasses do not stop growing during the flood period and might therefore occupy niches released by the affected dicotyledonous. [ABSTRACT FROM AUTHOR]

This paper intends basically to present the theoretical discussion over the category "Cultural Fronts" as on interpretative tool for the various struggle processes in order to obtain a more legitimate definition of the meaning of certain topics of everyday life. In the first place, the discussion will reach the four big issues where the Cultural Fronts are located: a) The social construction of the meaning, b) Hegemony and Cultural Power social constitution, c) The struggle for cultural legitimacy, d) The "trans-class" cultural elements and everyday life. Different sociological concepts will be shown, according to three possible levels of cultural analysis, in order to locate the place and the scale where the new category may be used. After the presentation and the discussion of the background and the categorical elements, a characterization of the Cultural Fronts is made, within the polisemic and the semantical implication of its composition. They are located both as struggle spaces or fronts, and simultaneously, as boundaries or limits for a specific contact between cultural conceptions and practices of different groups and classes that coexist in the same society. [ABSTRACT FROM AUTHOR]

Popular, meaning "a space of deep conflict", has gone a long way in order to be recognized by those in charge of studying social communication and culture in Latin America. Due to political changes and the reemergence of "democracies" in most part of the Continent, the preeminent paradigm, in the last two decades, has left its place to another one that recognizes and appraises the existence of new historical theoretical issues like trans-nationalization of culture, the meaning of the national, the emergence of ethnical considerations, masses, urban concerns; etc. All these topics are reviewed by the author in this paper. [ABSTRACT FROM AUTHOR]

For some nucleus the experimental value of the thermal neutron cross section for the (n, α) reaction is smaller than the estimated figure given the contribution of the neutron resonances. This can be explained by taking for granted the existence of destructive interference between the excited Stares associated with the compound nucleus levels. In this paper the possible interference in the (n, α) channel for the 145 60 Nd 67 30 Zn and 64 30 Zn nucleus is discussed. As to the letter the possibility of the existence of a bound state which could explain the observed effect is envisaged. [ABSTRACT FROM AUTHOR]

This paper presents an analysis of the characteristics of the safety aped.! systems: fast safety system and safety system by phase change, that are utilized In the critical assembly Mayak in periodically pulsed regime. It is describes the methodic of measurements and calculations of the effectiveness and rate of both systems The results obtained are given and analytically compared. These results and de operating experience of the systems demonstrate that It is possible to utilize the neutron surface block effect as the functioning principle of the fast safety system, and the WIMS-D4 and DOT Ill codes to perform the calculations The latter is re commended when performing calculations to search for perspective variants of the special safety systems and investigating the possible utilization of the principle of surface block of neutron absorption in the core of stationary research reactor of basin type in periodically pulsed regime. [ABSTRACT FROM AUTHOR]

In this paper, the study of Cuban zeolite to determine the possibility to use it in management of liquid radioactive waste of low activity has been performed. Some sorption characteristics of this material with Cs+, Sr2+ and Co2+ has been determined using radioactive indicator methods. [ABSTRACT FROM AUTHOR]

The author presents a primary research project on Mexican soap operas, begun in 1985, in three major areas: production, textural composition and differential social appropriations in six central mexican cities. The paper also presents a discussion and critical view of different approaches to television drama (effects, content, uses and gratifications, semeiotics and prodevelopment television). Current field research information is presented in figures that show the specific role Mexican soap operas play in television programming in general, among socially distinct viewers. The need for a multi-dimensional level analysis is presented here as a way to better understand this melodramatic phenomenon, so deeply rooted in the dynamics of the social construction of reality. [ABSTRACT FROM AUTHOR]

This paper presents the skeleton of a first-stage sample survey of six Mexican cities (Colima, Guadalajara, Leon, Mexico, Puebla and Veracruz) focusing on the different ways in which a probabalistic and quoted sample, representing approximately 85% of the Mexican urban population, perceives soap operas. An open and closed questionnaire, utilizing Likert's classic scales, provides much classified quantitative and qualitative information about who watches soap operas in Mexico (sex, social class, age), and the different ways in which viewers are related and have made a social appropriation of soap operas. This is one of the few current academic studies on the problematic relationship between social structures and television drama in Mexico. [ABSTRACT FROM AUTHOR]

As part of studies on the fungi of the State of Michoacan, Mexico, in this paper Trichoglossum velutipes (Peck) Durand is reported for the first time for the Mexican mycoflora. [ABSTRACT FROM AUTHOR]

In the present paper, the effect of fuel volume compensator of VVER type and the permutation of th fuel enrichment on the critical parameters of a configuration modelling a VVER-1000 has been determined. [ABSTRACT FROM AUTHOR]

In this paper, a method for determining the optimal height with the objective of decreasing the error in low-activity gamma measurements of different samples is combined with the use of liquid standards to measure the efficiency of semiconductor detectors. The procedure was applied to find the optimal height of measurement in the 1,460 MeV line of K40 in zeolites. [ABSTRACT FROM AUTHOR]

A new taxonomic treatment of the genus Tragia from Argentina and neighboring areas is provided. At present 15 taxa are recognized and four of them are recorded for the first time for Argentine. T. sellowiana (Klotzsch ex Baillon) Muell. Arg., T. bahiensis Muell. Arg., T. friesii Pax et K. Hoffman and T. uberabana Muell. Arg. var. discolor Chodat et Hassler. The history and systematic relationships within the genus and with other genera are presented. In this paper a new infrageneric classification is proposed. Three section are accepted for South America: Bia (Klotzsch) Muell. Arg., Leptorhachis (Klotzsch) Muell. Arg. and Tragia. Section Bia is recorded for the first time for Argentina; Section Leptorhachis, wich had been reduced to synonymy is rehabilited in this paper. According to this revision, Section Tragia includes Section Ratiga and Section Leucandra as synonyms. The most important morphological and anatomical features of the accepted taxa are discussed. Morphology of the inflorescence has been analized with the aim of establish its typology. A scanning electron microscopic study of the seed coat structure has been made in order to elucidate differences among the species. The taxonomic treatment includes a description of the genus, keys to the sections, species and varieties. All the taxa are described and illustrated. Data of the geographical distribution as well as a list of the selected herbarium material are given and 9 species and 14 varieties are reduced to synonymy for the first time. [ABSTRACT FROM AUTHOR]

This paper is a taxonomic revision of the genus Polygonum L in Argentina, with a discussion of the morphological characters of taxonomic importance, a description of the genus and a classification of the 20 species treated in 5 Sections. Polygonum (5 species), Amblygonon Meisner (1 species), Persicaria Meisner (11 species), Echinocaulon Meisner (2 species) and Tiniaria Meisner (1 species). For each species a description, illustrations of interesting characters, geographical distribution, observations and conclusions about the study of the type material, the information about karyology, phenology and probable uses are included. Some species or varieties previously cited for Argentina have been reduced to synonymy (Polygonum meisnerianum var. beyrichianum, P. lanigerum, P. portoricense, P. acuminatum var. microstemon and var. glabrescens, P. punctatum var. aquatile, P. berteroi, P arenastrum, P. persicarioides, P. cordobense and P. rivulare), P. polygaloides, P. spergulariaeforme and P. tenue are taxa erroneously cited for our country, while P. dumetorum is considered of doubtful presence in Argentina. [ABSTRACT FROM AUTHOR]

In the present paper the genus Junellia Mold. is accepted as such, and the limits towards related genera defined by means of a key. It is proposed to divide the genus into two subgenera: Junellia (with sections Junellia and Guedesia sect. nov.) and Thryothamnus (Phil.) stat. nov. (with sections Thryothamnus, Verticiflora (Schauer) stat. nov. and Junelliopsis sect. nov.), keys are provided for the identification of the infrageneric taxa here accepted, together with a provisional list of the species included. The type species of both subgenera are illustrated, and available information on karyology and geographical distribution is given, with a map showing the total range of the genus. A SEM study of the external and internal morphology of the mericarps with illustrations of diagnostic characters of the subgenera, and related genera are also included. [ABSTRACT FROM AUTHOR]

The ion-exchange and painting methods used in the Nuclear Analytical Laboratory of the Institute of Nuclear Science and Technology for the production of thin layers of uranium and thorium are described in this paper. The maximum thicknesses are 10 and 3 mg/cm² for uranium and thorium, respectively, using the painting method; while by ion-exchange about 2 mg/cm² uranium layer could be produced. Layers produced in the 0.06-0.4 mg/cm² interval can be applied in fission chambers. [ABSTRACT FROM AUTHOR]

This paper refers to the germination in Physalis philadelphica. Results show that seed germination occurs in a wide range of temperature (13 to 40°C), presenting the optimum between 25 and 37°C with more than 80% of germination. The seeds are photoblastic, but this characteristic is inhibited with the increment of temperature. The red/far red ratio needed to obtain high percentages of germination is over 0.9 at 30°C. [ABSTRACT FROM AUTHOR]