87 research outputs found

    RGE effects on the LFV scale from meson decays

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    We consider the lepton-flavor violating (LFV) lepton-quark dimension-6 operators and analyze their contributions to the LFV leptonic decays of vector, pseudoscalar, and scalar neutral mesons M12M\to \ell_1 \ell_2 as well as to μ(τ)ee,γγ\mu(\tau) \rightarrow \ell ee, \ell \gamma\gamma decays. These operators contribute to the purely leptonic processes via quark loop. On the basis of quark-hadron duality, we relate these loops to the appropriate meson-exchange contributions. In this way, we extract lower bounds on the individual scales of the studied LFV operators from the experimental and phenomenological limits on the leptonic decays of mesons and leptons. As a byproduct, we shall obtain new limits on the LFV leptonic decays of flavored mesons from the experimental bounds on the three-body lepton decays. We study the effects of QED and QCD radiative corrections to the LFV lepton-quark operators in question. We derive for them the one-loop matrix of the RGE evolution and examine its effect on the previously derived tree-level limits on these operators. We show that the QED corrections are particularly relevant due to operator mixing. Specifically, for some of them the limits on their individual LFV scales improve by up to 3 orders of magnitude.Comment: 20 pages, 1 figur

    Modificações territoriais induzidas pelas usinas hidrelétricas do Rio Uruguai, no Oeste Catarinense.

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    Esta tese intitulada “Modificações territoriais induzidas pelas usinas hidrelétricas do rio Uruguai, no Oeste Catarinense” visa contribuir com os processos de investigação sobre a produção de energia por hidrelétricas no Brasil. Fundamenta-se nas categorias teóricas Espaço, Território e Desenvolvimento, e é resultado do processo de pesquisa da autora, para o doutoramento em Geografia pela Universidade Federal de Santa Catarina (UFSC). Teve como objetivo central identificar as modificações territoriais induzidas nos respectivos municípios-sede pelas hidrelétricas de Itá, Machadinho e Foz do Chapecó, localizadas na bacia do rio Uruguai. O estudo baseou-se na perspectiva de uma pesquisa qualitativa-quantitativa, entendendo que o objeto investigado necessitava da complementaridade das duas abordagens, negando, dessa forma, a distinção entre fato e valores, como apregoa a visão positivista. Os sujeitos sociais envolvidos na pesquisa foram os empreendedores, as lideranças comunitárias que representam uma coletividade, os gestores públicos e os dirigentes locais do Movimento dos Atingidos pelas Barragens (MAB). Os dados primários foram coletados através de entrevistas do tipo semiestruturada. Os dados secundários foram coletados através de análise documental, utilizada com uma função de “complementaridade na investigação qualitativa”, ou seja, “para triangular os dados obtidos através de uma ou duas outras técnicas”. Constituem-se cenários deste trabalho as estratégias de governos e de grupos privados e, de outro lado, visões e versões de grupos sociais atingidos pelos empreendimentos hidrelétricos e também movimentos sociais ligados à temática. O estudo classificou em fases sequenciais e interrelacionadas as modificações territoriais induzidas, analisando-as do ponto de vista das mudanças nos modos de vida, na organização e gestão municipal e estendendo-se para algumas alterações no campo econômico. Conclui-se que o tema continua sendo polêmico, complexo e contraditório, fortemente vinculado a um modelo desenvolvimentista de contínuo aumento na geração e fornecimento de energia, ficando em segundo plano as questões sociais e ambientais dos espaços diretamente afetados. Os dados apontam para um conjunto de modificações territoriais que se materializam em novos objetos técnicos, em novas atividades econômicas e numa alteração significativa nas relações sociais

    Cladoceros limnéticos de la provincia de La Pampa (Argentina)

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    In this contribution we report the presence of 10 species belonging to the families Sididae, Daphnidae, Moinídae, Bosminidae and Chydoridae found in temporary and permanent water bodies of La Pampa province (Argentina).En esta contribución se da a conocer la presencia de diez especies pertenecientes a las familias Sídidae, Daphynídae, Moinídae, Bosminidae y Chydoridae en distintos cuerpos de agua temporarios y permanentes de la provincia de La Pampa (Argentina)

    Composición y variación anual de la taxocenosis de cladóceros (Crustacea: Anomopoda y Ctenopoda) planctónicos y química del agua de la laguna Don Tomás (La Pampa, Argentina)

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    Variations in the taxonomic composition and densities of the species of the community of planktonic cladocerans of a low salinity pond of La Pampa province were analyzed over a one year period on the basis of monthly samplings. Diversity and species richness were higher than in other provincial water bodies, probably ow into the low salinity of this water body. Nine species were recorded: Moina micrura Kurz, 1874, Bosmina huaronensis Delachaux, 1918, Afona sp. Baird, 1843, Macrothrix sp. Baird, 1843, Leydigia feydigi Schoedler, 1863, Ceriodaphnia cf. Dubia Richard, 1895, Daphnia cf.obtusa Kurz,1874, Daphnia spinufata Birabén, 1917 y Diaphanosoma birgei Korínek, 1981. Although the planktonic species B. huaronensis was dominant, the ticoplankter Afona sp. also attained high densities. D. birgei, registered in other ponds of the province with different physical and chemical characteristics was also recorded in the studied pondo Most of the detected species were small, probably owing to the effect of selective predation by fish.Se analizó la variación en la composición taxonómica y densidad de las especies de la comunidad de c1adóceros planctónicos de una laguna de baja salinidad de la provincia de La Pampa, mediante muestreos mensuales a lo largo de un ciclo anual. La diversidad y la riqueza específica fueron mayores que en otros ambientes provinciales, probablemente debido al bajo contenido de sales del agua. Se registraron nueve especies: Moina micrura Kurz, 1874, Bosmina huaronensis Delachaux, 1918, Afona sp. Baird, 1843, Macrothrix sp. Baird, 1843, Leydigia leydigi Schoedler, 1863, Ceriodaphnia cf. dubia Richard, 1895, Daphnia cf. obtusa Kurz, 1874, Daphnia spinulata Birabén, 1917 y Diaphanosoma birgei Korínek, 1981. Se verificó el predominio de B. huaronensis, especie típicamente planctónica, pero el ticoplanctonte Alona sp. también alcanzó densidades muy altas. Se menciona la presencia de D. birgei, especie que había sido registrada en cuerpos de agua de la provincia con características físico-químicas distintas a las de esta laguna. La mayor parte de las especies detectadas fue de pequeño tamaño, probablemente debido al efecto de la predación selectiva por parte de peces

    Associations of ostracods in shallow lakes in the northeast of La Pampa province (Argentina)

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    Los lagos someros son frecuentes en La Pampa. Aunque muchas características de su biota son conocidas, la información sobre la distribución y ecología de los ostrácodos es escasa, a pesar de su importancia como indicadores biológicos y en actuopaleontología. El objetivo de este estudio es conocer la composición taxonómica, la densidad de ostrácodos y sus relaciones con parámetros ambientales en lagos del noreste de La Pampa. Se estudiaron cinco lagos desde septiembre de 2016 hasta marzo de 2017. Se tomaron muestras de sedimentos superficiales e in situ se midieron: conductividad, temperatura y transparencia y se tomaron muestras para determinar salinidad, pH y composición iónica. Los lagos difirieron en su salinidad, composición iónica y transparencia. Se registraron diez taxa, algunos hallados previamente en la provincia de Buenos Aires (Heterocypris similis, Heterocypris incongruens, Cypridopsis vidua y Chlamydotheca incisa), la cuenca de Llancanelo (H. incongruens y C. vidua) y lagos del norte de Patagonia (C. incisa, C. vidua, Potamocypris unicaudata, H. incongruens y Amphicypris argentiniensis). Se comprobó la influencia de la salinidad ya que algunas especies (A. argentinensis, Limnocythere rionegroensis y Limnocythere titicaca) se encontraron sólo en el lago más salino. La existencia en La Pampa de tres ecorregiones diferentes (Llanura Pampeana, Espinal y Estepa Patagónica) y la presencia en los lagos estudiados de ostrácodos del noroeste argentino (L. titicaca), de la llanura bonaerense (H. similis, H. incongruens) y otras de Patagonia (L. rionegroensis), permitiría afirmar que los lagos de La Pampa están en una zona de transición entre faunas diferentes.Shallow lakes are common in the center of Argentina. Although many characteristics of its biota are known, information on the distribution and ecology of ostracods is scarce despite their importance as biological indicators and in actuopaleontology. The objective of this study was to determine the taxonomic composition, the density of ostracods, and their relationships with environmental parameters in lakes in the northeast of La Pampa. Five aquatic ecosystems were studied from September 2016 to March 2017. Samples of superficial sediments were collected, and conductivity, temperature, and transparency were measured in situ. Water samples were collected to determine salinity, pH, and ionic composition. The lakes differed in salinity, ionic composition, and transparency. Ten taxa were registered, some previously found in the province of Buenos Aires (Heterocypris similis, Heterocypris incongruens, Cypridopsis vidua, and Chlamydotheca incisa), the Llancanelo basin (H. incongruens and C. vidua), and North Patagonia lakes (C. incisa, C. vidua, Potamocypris unicaudata, H. incongruens, and Amphicypris argentiniensis). The influence of salinity was verified because some species (A. argentinensis, Limnocythere rionegroensis, and Limnocythere titicaca) were found only in the most saline lake. The existence in La Pampa of three different ecoregions (Pampean Plains, Espinal, and Patagonian Steppe) and the presence of ostracods in the studied lakes of northwestern Argentina (L. titicaca), the Buenos Aires province plain (H. similis, H. incongruens), and Patagonia (L. rionegroensis) allowed for affirming that the lakes of La Pampa are in a transition zone among different ostracods faunas.Fil: Kihn, Romina Gisela. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias de la Tierra y Ambientales de La Pampa. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de La Pampa; ArgentinaFil: Echaniz, Santiago Andrés. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Vignatti, Alicia María. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Cabrera, Gabriela Cecilia. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Stella, Cesar A.. Museo Provincial de Ciencias Naturales; Argentin

    Cambios en la diversidad y variación interanual de la abundancia del zooplancton de un lago somero urbano de La Pampa

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    Don Tomás is an urban, turbid and hypereutrophic shallow lake located in the west side of Santa Rosa. As it has an important silverside population (Odontesthes bonariensis) this lake is important for recreational and touristic activities. As many changes in many limnological parameters were observed, including zooplankton composition and abundance between 1995-96 and 2006, the main objective of this research was to compare these parameters with the ones obtained from September 2008 to August 2009. Salinity decreased along the three periods from 1.65 (1995-96) to 0.65 g.l-1 (2008-09) mainly due to the city runoff and the constant water pumping for irrigation. Water transparency also decreased from 0.24 (1995-96) to 0.14 m (2008-09). Zooplankton total richness did not change, but changes in taxonomical composition were observed when groups were separately analyzed (cladoceran richness decreased and rotifers increased during 2006. Cladoceran richness decreased from 9 species in 1995-96 to 4 in 2006, to only 2 species in 2008-2009. The same pattern was observed with copepod richness which decreased from 4 species in 2006 to only 2 species in 2008-09. Rotifer richness, on the other hand, increased from 8 species (1995-96) to 15 (2008-2009). The decreased water transparency could have been due to the lack of Daphnia (observed only in 1995-96) and the increased dominance of rotifers. Total zooplankton abundance showed important inter-annual differences, being the lowest in 2006. The obtained results reveal the wide variability of zooplankton in this type of environment.Instituto de Limnología "Raúl A. Ringuelet

    Cambios en la diversidad y variación interanual de la abundancia del zooplancton de un lago somero urbano de La Pampa

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    Don Tomás is an urban, turbid and hypereutrophic shallow lake located in the west side of Santa Rosa. As it has an important silverside population (Odontesthes bonariensis) this lake is important for recreational and touristic activities. As many changes in many limnological parameters were observed, including zooplankton composition and abundance between 1995-96 and 2006, the main objective of this research was to compare these parameters with the ones obtained from September 2008 to August 2009. Salinity decreased along the three periods from 1.65 (1995-96) to 0.65 g.l-1 (2008-09) mainly due to the city runoff and the constant water pumping for irrigation. Water transparency also decreased from 0.24 (1995-96) to 0.14 m (2008-09). Zooplankton total richness did not change, but changes in taxonomical composition were observed when groups were separately analyzed (cladoceran richness decreased and rotifers increased during 2006. Cladoceran richness decreased from 9 species in 1995-96 to 4 in 2006, to only 2 species in 2008-2009. The same pattern was observed with copepod richness which decreased from 4 species in 2006 to only 2 species in 2008-09. Rotifer richness, on the other hand, increased from 8 species (1995-96) to 15 (2008-2009). The decreased water transparency could have been due to the lack of Daphnia (observed only in 1995-96) and the increased dominance of rotifers. Total zooplankton abundance showed important inter-annual differences, being the lowest in 2006. The obtained results reveal the wide variability of zooplankton in this type of environment.Instituto de Limnología "Raúl A. Ringuelet

    Efecto del lavado de la ciudad de Santa Rosa sobre el estado trófico de una laguna arreica

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    Don Tomás is a shallow, hypereutrophic lake that received sewage inputs from the city of Santa Rosa until 1987. In 1993, the main body of water was divided into smaller adjacent ponds. One of these ponds, Canotaje pond (with a small surface area and average depth), receives an important urban runoff from the city. Thus, the high load of nutrients and sediments after a storm should result in a higher trophic state than Don Tomás. The objective of this research was to compare the limnological characteristics of both water bodies to verify their trophic status. We did not find any significant statistical differences among the measured variables in the two systems, except for water conductivity and suspended organic solids, which were higher in Don Tomás, and for dissolved phosphorus, which was higher in Canotaje. Laboratory experiments determined that the phytoplankton community of both systems was limited by nitrogen, which is consistent with the observed low Redfield ratio of dissolved N and P (1.32). Algal diversity in both systems was represented by 66 taxa, 1/3 of which belonged to the phylum Cyanophyta. In addition, a Planktothrix agardhii bloom was observed in both water bodies. From the present study, we determined that Don Tomás and Canotaje have the same trophic state (i.e. hypereutrophic). In spite of the high urban runoff loaded with nutrients and sediments into Canotaje, the high amounts of P present in this system sediments would make both ponds highly resilient to changes in trophic state.Don Tomás is a shallow, hypereutrophic lake that received sewage inputs from the city of Santa Rosa until 1987. In 1993, the main body of water was divided into smaller adjacent ponds. One of these ponds, Canotaje pond (with a small surface area and average depth), receives an important urban runoff from the city. Thus, the high load of nutrients and sediments after a storm should result in a higher trophic state than Don Tomás. The objective of this research was to compare the limnological characteristics of both water bodies to verify their trophic status. We did not find any significant statistical differences among the measured variables in the two systems, except for water conductivity and suspended organic solids, which were higher in Don Tomás, and for dissolved phosphorus, which was higher in Canotaje. Laboratory experiments determined that the phytoplankton community of both systems was limited by nitrogen, which is consistent with the observed low Redfield ratio of dissolved N and P (1.32). Algal diversity in both systems was represented by 66 taxa, 1/3 of which belonged to the phylum Cyanophyta. In addition, a Planktothrix agardhii bloom was observed in both water bodies. From the present study, we determined that Don Tomás and Canotaje have the same trophic state (i.e. hypereutrophic). In spite of the high urban runoff loaded with nutrients and sediments into Canotaje, the high amounts of P present in this system sediments would make both ponds highly resilient to changes in trophic state

    Producción primaria fitoplanctónica de un lago somero turbio orgánico en relación con el zooplancton (La Pampa, Argentina)

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    Primary production (PPr) is the energy fixed by autotrophic organisms. In aquatic ecosystems, it is mostly produced by photosynthetic processes performed by planktonic or benthic algae and macrophytes. In La Pampa, the ecology of shallow lakes has recently begun to be studied, but there is no reference inade to the algal PPr and how it is influenced by zooplankton. Since shallow lakes in La Pampa are different from those widely studied in Buenos Aires province, the objective of this contribution was to determine the phytoplanktonic PPr of an organic turbid shallow lake of the northeast La Pampa, and the influence of zooplankton in its valué. PPr was estimated 6 times along the day with the dissolved oxygen technique, using clear and dark bottles. To test the ef- fect of zooplankton on PPr estimates, we compared PPr with and without zooplankton, which was removed with a 40-micron mesh net. A higher concentration of nutrients was recorded than the typical pampasic shallow lakes of Buenos Aires province, Phytoplank- ton was dominated by Chlorophyta and the zooplankton assemblage was typical of low salinity environments. Zooplankton densities were reduced during noon-afternoon hours, what might indícate an important zooplankton migration process. Net PPr was similar to the detected in lakes at similar latitudinal location, but the máximum PPr per unít chlorophyll was higher than the recorded in organic turbid lakes of Buenos Aires Province. Zooplankton had a weak influence on PPr. Determinations from the two treat- ments did not show significant differences, except at 8 PM when the net PPr without zooplankton was three times higher than the treaíment with zooplankton.Instituto de Limnología "Raúl A. Ringuelet
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