Palynology on lake sediments from the Pyrenees

A multi-proxy palaeoecological investigation including pollen, plant macrofossil, radiocarbon and sedimentological analyses, was performed on a small mountain lake in the Eastern Pyrenees. This has allowed the reconstruction of: (1) the vegetation history of the area based on five pollen diagrams and eight AMS14C dates and (2) the past lake-level changes, based on plant macrofossil, lithological and pollen analysis of two stratigraphical transects correlated by pollen analysis. The palaeolake may have appeared before the Younger Dryas; the lake-level was low and the vegetation dominated by cold steppic grasslands. The lake-level rose to its highest level during the Holocene in the Middle Atlantic (at ca. 5060±45 b.p.). Postglacial forests (Quercetum mixtum and Abieto-Fagetum) developed progressively in the lower part of the valley, while dense Pinus uncinata forests rapidly invaded the surroundings of the mire and remained the dominant local vegetation until present. The observed lowering of the lake levels during the Late Atlantic and the Subboreal (from 5060 ± B.P. to 3590±40 b.p.) was related to the overgrowth of the mire. The first obvious indications of anthropogenic disturbances of the vegetation are recorded at the Atlantic/Subboreal boundary as a reduction in the forest component, which has accelerated during the last two millennia.

Palynological and stratigraphic record from Löddigsee in Mecklenburg-Vorpommern, Germany

A Late Pleistocene and Holocene sediment core from the nowadays terrestrialised portion of the Löddigsee in Southern Mecklenburg, Germany was palynologically investigated. The lake is situated in the rarely investigated Young moraine area at the transition from the Weichselian to the Saalian glaciation. The high-resolution pollen diagram contributes to the establishment of the north-eastern German Late Pleistocene pollen stratigraphy. The vegetation distribution pattern after the end of the Weichselian is in good agreement with other studies from North-eastern Germany, but also has its own characteristics. The Holocene vegetation development reveals features from the north-eastern and north-western German lowlands. A special focus was laid on the environmental history of the two settlements on an island within the lake (Late Neolithic and Younger Slavic period), which were preserved under moist conditions. Both settlements were constructed during a period of low lake level. Although there is evidence of agriculture in the area during the respective periods, the two island settlements seem to have served other purposes.

Hierolexicon linguarum orientalium, hebraicae, Chaldaicae et Syriacae : in quo radices imperfectae omnes integrantur... ; et cuiusque harum linguarum grammatica... /

Trifolium hebraicum, sive nova grammaticae Biblicae methodus ..., 48 p. ; Trifolium chaldaicum, sive nova grammaticae methodes ..., 50 p. ; Trifolium syriocum, sive nova grammaticae methodus ..., 47 p.

Nitrogen transfer within and between plants through common mycorrhizal networks (CMNs)

Mycorthizae play a critical role in nutrient capture from soils. Arbuscular mycorrhizae (AM) and ectomycorrhizae (EM) are the most important mycorrhizae in agricultural and natural ecosystems. AM and EM fungi use inorganic NH4+ and NO3-, and most EM fungi are capable of using organic nitrogen. The heavier stable isotope N-15 is discriminated against during biogeochemical and biochemical processes. Differences in N-15 (atom%) or delta(15)N (parts per thousand) provide nitrogen movement information in an experimental system. A range of 20 to 50% of one-way N-transfer has been observed from legumes to nonlegumes. Mycorrhizal fungal mycelia can extend from one plant's roots to another plant's roots to form common mycorrhizal networks (CMNs). Individual species, genera, even families of plants can be interconnected by CMNs. They are capable of facilitating nutrient uptake and flux. Nutrients such as carbon, nitrogen and phosphorus and other elements may then move via either AM or EM networks from plant to plant. Both N-15 labeling and N-15 natural abundance techniques have been employed to trace N movement between plants interconnected by AM or EM networks. Fine mesh (25similar to45 mum) has been used to separate root systems and allow only hyphal penetration and linkages but no root contact between plants. In many studies, nitrogen from N-2-fixing mycorrhizal plants transferred to non-N-2-fixing mycorrhizal plants (one-way N-transfer). In a few studies, N is also transferred from non-N-2-fixing mycorrhizal plants to N-2-fixing mycorrhizal plants (two-way N-transfer). There is controversy about whether N-transfer is direct through CMNs, or indirect through the soil. The lack of convincing data underlines the need for creative, careful experimental manipulations. Nitrogen is crucial to productivity in most terrestrial ecosystems, and there are potential benefits of management in soil-plant systems to enhance N-transfer. Thus, two-way N-transfer warrants further investigation with many species and under field conditions.

Reciprocal N ((NH4+)-N-15 or (NO3-)-N-15) transfer between nonN(2)-fixing Eucalyptus maculata and N-2-fixing Casuarina cunninghamiana linked by the ectomycorrhizal fungus Pisolithus sp.

Two-way N transfers mediated by Pisolithus sp. were examined by excluding root contact and supplying (NH4+)-N-15 or (NO3-)-N-15 to 6-month-old Eucalyptus maculata or Casuarina cunninghamiana grown in two-chambered-pots separated by 37 m screens. Mycorrhizal colonization was 35% in Eucalyptus and 66% in Casuarina (c. 29% N-2-fixation). Using an environmental scanning electron microscope, living hyphae were observed to interconnect Eucalyptus and Casuarina. Biomass and N accumulation was greatest in nodulated mycorrhizal Casuarina/mycorrhizal Eucalyptus pairs, less in nonnodulated mycorrhizal Casuarina/mycorrhizal Eucalyptus pairs, and least in nonnodulated nonmycorrhizal Casuarina/nonmycorrhizal Eucalyptus pairs. In nonnodulated mycorrhizal pairs, N transfers to Eucalyptus or to Casuarina were similar (2.4-4.1 mg per plant in either direction) and were 2.6-4.0 times greater than in nonnodulated nonmycorrhizal pairs. In nodulated mycorrhizal pairs, N transfers were greater to Eucalyptus (5-7 times) and to Casuarina (12-18 times) than in nonnodulated mycorrhizal pairs. Net transfer to Eucalyptus or to Casuarina was low in both nonnodulated nonmycorrhizal (< 0.7 mg per plant) and nonnodulated mycorrhizal pairs (< 1.1 mg per plant). In nodulated mycorrhizal pairs, net transfer to Casuarina was 26.0 mg per plant. The amount and direction of two-way mycorrhiza-mediated N transfer was increased by the presence of Pisolithus sp. and Frankia, resulting in a net N transfer from low-N-demanding Eucalyptus to high-N-demanding Casuarina.

Parasite-host interaction of the protoplast isolates of Entomophthora egressa with the eastern hemlock looper and the eastern spruce budworm

Hemocytes of the insects Lambdina fiscellaria fiscellaria and Choristoneura fumiferana did not adhere to the protoplasts of ~he fungus EntomoEhthora egressa. Hemocyte reaction for both insect species to test-particles was not suppressed by the protoplasts. The spherule cells of _-L. fiscellaria fiscellaria adhered to the spherical hyphal bodies and hyphae of ~· ~gressa. The granular cells of -c. fumiferana adhered to the hyphae of ~· egress~. Protoplasts exposed to papain were attacked by the granular ·cells of -c. fumiferana. Spent growth medium of both protoplast isolates produced paralysis when injected into -c. fumiferana larvae. Evidence suggests that heat-stable proteins may be involved. Protoplast isolates showed differences in the growth rates and regeneration sequences using coagulated egg yolk medium, a highly modified version of Grace's insect tissue . culture medium (MGM) and modifications of MGM and in the presence of C0₂. The isolates also differed in the changes that they induced in MGM composition during protoplast growth and in the rates of glucose utilization and protein secretion. The serum of c. fumiferana larvae contained protein(s) which we believe adhere to the cell membranes of the protoplasts of E. egressa. Evidence is presented for hemocyteplasn~ interaction in the presence of protoplasts. Components in the larval serum were found to influence protoplast growth patterns. The possibility of antiprotoplast serum activity is presented. Melanin, toxic levels of ninhydrinpositive compounds and antiprotoplast proteins may have been involved in this activity. The granular cells of -L. fiscellaria fiscellaria and Q• fumiferana adhered to the hyphae of ,Rhizopus ~i$rican~. Spores of Absidia repens and the bacteria Escherichia coli and Bacillus cereus adhered to the granular cells of both species of· insects. The granular cells and plasmatocytes of -c. fumiferana were capable of phagocytosing -B. cereus. Adhesion of .A... . repens spores to c. fumiferana granular cells ~ . - was stimulated by N-acetylglucosamine and glucosamine, moderately reduced by D-fucose, D-arabinose, D-mannose, D-galatose and sucrose and mildly reduced by D-glucose, D-fructose and trehalose. There was no evidence of humoral opsonins in larval hemolymph favoring test-particle-hemocyte interaction. Granular cells of c. fumiferana exposed to papain had reduced affinities for A. repens spores.

Arte y política : Un estudio comparativo de Jacques Rancière y Nelly Richard para el arte latinoamericano

En este artículo se indagan y comparan las teorías de Jacques Rancière y Nelly Richard sobre la relación entre arte y política desde el pensamiento posfundacional, y se producen reflexiones y análisis de manifestaciones artísticas latinoamericanas vanguardistas o críticas en diálogo con ambas. Para ello, se parte de una presentación de las teorías de Rancière y Richard en términos generales, se focaliza en las ideas que dichos autores ;tienen de la política y, específicamente, en la conceptualización que hacen del arte y su relación con la política. Al mismo tiempo, se desarrolla una interpretación de producciones artísticas desde una mirada centrada en sus diversas conexiones con lo político, más allá del contenido temático de estas. Se utiliza la perspectiva metodológica cualitativa transdisciplinaria, que articula distintas áreas de conocimiento (filosofía política, sociología, historia del arte). En el caso de los desarrollos de Jacques Rancière, se recurre a herramientas teóricas metropolitanas para resituarlas y repensarlas en función del arte de Latinoamérica. En este sentido, se trata de potenciar sus ideas en el análisis de casos ;locales. En cuanto a la teoría de Nelly Richard, sus conceptos de arte crítico y vanguardista se ponen en relación con el arte latinoamericano. Finalmente, se propone una comparación en la cual se destacan similitudes y diferencias conceptuales entre ambos en combinación con análisis de casos para abrir el panorama analítico e interpretativo que vincule teorías actuales con estudios de manifestaciones artísticas locales

Arte y política : Un estudio comparativo de Jacques Rancière y Nelly Richard para el arte latinoamericano

En este artículo se indagan y comparan las teorías de Jacques Rancière y Nelly Richard sobre la relación entre arte y política desde el pensamiento posfundacional, y se producen reflexiones y análisis de manifestaciones artísticas latinoamericanas vanguardistas o críticas en diálogo con ambas. Para ello, se parte de una presentación de las teorías de Rancière y Richard en términos generales, se focaliza en las ideas que dichos autores ;tienen de la política y, específicamente, en la conceptualización que hacen del arte y su relación con la política. Al mismo tiempo, se desarrolla una interpretación de producciones artísticas desde una mirada centrada en sus diversas conexiones con lo político, más allá del contenido temático de estas. Se utiliza la perspectiva metodológica cualitativa transdisciplinaria, que articula distintas áreas de conocimiento (filosofía política, sociología, historia del arte). En el caso de los desarrollos de Jacques Rancière, se recurre a herramientas teóricas metropolitanas para resituarlas y repensarlas en función del arte de Latinoamérica. En este sentido, se trata de potenciar sus ideas en el análisis de casos ;locales. En cuanto a la teoría de Nelly Richard, sus conceptos de arte crítico y vanguardista se ponen en relación con el arte latinoamericano. Finalmente, se propone una comparación en la cual se destacan similitudes y diferencias conceptuales entre ambos en combinación con análisis de casos para abrir el panorama analítico e interpretativo que vincule teorías actuales con estudios de manifestaciones artísticas locales

Arte y política : Un estudio comparativo de Jacques Rancière y Nelly Richard para el arte latinoamericano

En este artículo se indagan y comparan las teorías de Jacques Rancière y Nelly Richard sobre la relación entre arte y política desde el pensamiento posfundacional, y se producen reflexiones y análisis de manifestaciones artísticas latinoamericanas vanguardistas o críticas en diálogo con ambas. Para ello, se parte de una presentación de las teorías de Rancière y Richard en términos generales, se focaliza en las ideas que dichos autores ;tienen de la política y, específicamente, en la conceptualización que hacen del arte y su relación con la política. Al mismo tiempo, se desarrolla una interpretación de producciones artísticas desde una mirada centrada en sus diversas conexiones con lo político, más allá del contenido temático de estas. Se utiliza la perspectiva metodológica cualitativa transdisciplinaria, que articula distintas áreas de conocimiento (filosofía política, sociología, historia del arte). En el caso de los desarrollos de Jacques Rancière, se recurre a herramientas teóricas metropolitanas para resituarlas y repensarlas en función del arte de Latinoamérica. En este sentido, se trata de potenciar sus ideas en el análisis de casos ;locales. En cuanto a la teoría de Nelly Richard, sus conceptos de arte crítico y vanguardista se ponen en relación con el arte latinoamericano. Finalmente, se propone una comparación en la cual se destacan similitudes y diferencias conceptuales entre ambos en combinación con análisis de casos para abrir el panorama analítico e interpretativo que vincule teorías actuales con estudios de manifestaciones artísticas locales