Search for the Heliospheric Termination Shock (TS) and Heliosheath (HS)

Voyager 1 continues to measure the very distant Heliospheric Magnetic Field (HMF) beyond 95 AU at ~35 North latitude. The MAG instrument data covers more than a full 22 years solar magnetic cycle. The magnitude of the observed HMF is well described, on average, by Parker's Archimedean spiral structure if due account is made for time variations of the source field strength and solar wind velocity. The V1 magnetic field observations do not provide any evidence for a field increase associated with entry into a subsonic solar wind region, such as the heliosheath is expected to be, nor an exit from this regime. We see no evidence for crossing of the Termination Shock (TS) as has been reported at ~85 AU by the LECP instrument. Merged Interaction Regions are identified by an increased HMF and associated decreases in the flux of >70 MeV/nuc cosmic rays which are then followed by a flux recovery. This CR-B relationship has been identified in V1 data and studied since 1982 when V1 was at 11 AU. The variance of HMF, a direct measure of the energy**1/2 in the HMF fluctuations, shows no significant changes associated with the alleged TS crossings in 2002–2003. Thus, the absence of any HMF increase at the entry into the heliosheath appears not to be due to the onset of mesoscale turbulence as proposed by Fisk. The TS has yet to be directly observed in-situ by the V1 MAG experiment in data through 2003

Seasonal Expression of Apospory in Bahiagrass

Flowering plants can reproduce sexually (outcrossing and/or selfing) and/or asexually. Sexual reproduction implies the successful completion of meiosis and double fertilisation for the formation of both the embryo and the endosperm. In contrast, gametophytic apomixis is an asexual mode of reproduction through seeds that involves parthenogenetic embryo development from a cytologically unreduced egg cell (2n). Apospory is the process by which unreduced gametophytes are formed after a series of mitotic divisions of somatic cells (2n) in the ovary. This occurs independently from the sexual meiotic process; and therefore, both sexual and apomictic pathways may coexist simultaneously. Apospory is inherited in bahiagrass (Paspalum notatum) as a single dominant Mendelian factor with distorted segregation (Martínez et al. 2001), and its degree of expression was reported to vary throughout the flowering season in P. cromyorrhizon, a close relative of bahiagrass (Quarin 1986). Bahiagrass is a perennial warm-season grass widely used for forage and utility turf in the south-eastern US due to its persistence in sandy, infertile soils. Diploid races reproduce sexually and are highly self-incompatible (Acuña et al. 2007), while polyploids are classified as pseudogamous apomicts (pollination is required) (Quarin 1999). Sexual tetraploid genotypes have been experimentally created (Quesenberry and Smith 2003; Quesenberry et al. 2010) and successfully used in crosses (Acuña et al. 2009). Cytoembryological analysis has been used to determine the mode of reproduction in bahiagrass (Martínez et al. 2001; Acuña et al. 2007). At anthesis, sexual plants produce spikelets having only a single Polygonum type meiotic embryo sac (SES), characterised by bearing the egg apparatus close to the micropyla, a large binucleated central cell and a group of antipodal cells at the chalazal end (Figure 1a). Highly apomictic plants produce ovules having single or multiple aposporous embryo sacs (AES), which present the egg apparatus and a central cell with 2 polar nuclei, and no antipodal cells (Figure 1b). Some tetraploid bahiagrass races are also able to produce ovules that have the sexual meiotic megasporocyte together with one or more aposporous sacs (AES+SES), and these plants are classified as facultative apomictic. The objective of this study was to characterise the reproductive mode of 5 wild dwarf bahiagrasses, a highly apomictic hybrid (Acuña et al. 2009) and the cultivar ‘Argentine’ at different times during the flowering season and under different nitrogen (N) fertiliser rates

Sturmian morphisms, the braid group B_4, Christoffel words and bases of F_2

We give a presentation by generators and relations of a certain monoid generating a subgroup of index two in the group Aut(F_2) of automorphisms of the rank two free group F_2 and show that it can be realized as a monoid in the group B_4 of braids on four strings. In the second part we use Christoffel words to construct an explicit basis of F_2 lifting any given basis of the free abelian group Z^2. We further give an algorithm allowing to decide whether two elements of F_2 form a basis or not. We also show that, under suitable conditions, a basis has a unique conjugate consisting of two palindromes.Comment: 25 pages, 4 figure

Genetic transfer from several apomictic tetraploid Paspalum species to an elite group of sexual plants

Basic findings from classical genetic studies are available for exploiting apomixis in the breeding of several forage grass genera. Most Paspalum species are multiploid with a sexual diploid cytotype and conspecific apomictic polyploid (mainly tetraploid) cytotypes. Experimental tetraploidized diploids reproduce sexually and, when crossed with natural apomictic tetraploids, yield hybrid populations that segregate for reproductive mode. Genetic studies indicated that apomixis is inherited as a monogenic dominant factor. We recombined 50 selected sexual hybrids obtained from crosses between a tetraploidized sexual genotype of P. plicatulum and 9 natural apomictic tetraploid accessions of 6 species of the Plicatula group. A synthetic sexual tetraploid population (SSTP) of 600 individuals from mixed seed of the 50 intercrossed hybrids was space-planted in the field. Based on evaluations of plant vigor, seed set, ergot tolerance, regrowth after flowering, and cold tolerance, 31 plants were selected. Crosses between most selected plants and two testers, which belonged to P. guenoarum, were performed, and the generated progeny was planted into the field following a randomized block design with 3 replications. The progeny test was evaluated for seed fertility, biomass yield, and cold tolerance. This procedure allowed selection of 10 elite plants from the SSTP. These plants should contain genes recombined from six apomictic species, without the genetic determinants for apomixis. They may be polycrossed to generate an improved sexual population, or crossed with other apomictic genotypes to obtain improved apomictic hybrids.Fil: Novo, Patricia Elda. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; ArgentinaFil: Acuña, Carlos Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; ArgentinaFil: Urbani, Mario Hugo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; ArgentinaFil: Galdeano, Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; ArgentinaFil: Espinoza, Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; ArgentinaFil: Quarin, Camilo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; Argentin

Global distribution of two fungal pathogens threatening endangered sea turtles

This work was supported by grants of Ministerio de Ciencia e Innovación, Spain (CGL2009-10032, CGL2012-32934). J.M.S.R was supported by PhD fellowship of the CSIC (JAEPre 0901804). The Natural Environment Research Council and the Biotechnology and Biological Sciences Research Council supported P.V.W. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Thanks Machalilla National Park in Ecuador, Pacuare Nature Reserve in Costa Rica, Foundations Natura 2000 in Cape Verde and Equilibrio Azul in Ecuador, Dr. Jesus Muñoz, Dr. Ian Bell, Dr. Juan Patiño for help and technical support during samplingPeer reviewedPublisher PD

Análise ecointegradora do manejo florestal sustentável de estoques madeireiros na Amazônia sul ocidental - Brasil.

O presente trabalho propõe uma modelagem de interpretação transdisciplinar, sob a visão da economia ecológica e do enfoque ecointegrador proposto por Naredo (1987), aplicado nos resultados dos limites físicos dos monitoramentos florestais efetuados pela EMBRAPA do Estado do Acre, em estoques madeireiros de uma área de Floresta Ombrófila Aberta com presença de espécies de Guadua spp. na Amazônia Sul Ocidental do Brasil. O método aplicado oferece maiores opções de compreensão para a gestão florestal na Amazônia, através de uma visão financeira da evolução das taxas efetivas dos estoques ao longo do tempo. A determinação do ponto de equilíbrio monetário (PEM) e das análises dos índices de mercado da atividade permitem o entendimento bioeconômico e financeiro, isento da arbitragem de taxas de desconto futuras em cenários incertos e utilizando somente variáveis ecológicas e econômicas conhecidas. O modelo pode ser aplicado a qualquer momento, entre os ciclos de corte da operação florestal e confirma a necessidade da prática do monitoramento de florestas tropicais para acompanhar os efeitos antrópicos da exploração, efeitos dos fenômenos extremos provocados pelas mudanças climáticas e a evolução dos estoques do capital natural

Análisis y supervisión de la señal cardiaca con transmisión inalámbrica de datos

En este trabajo se describe el diseño y la implementación de un prototipo de transmisión vía RF para el análisis y supervisión de la señal cardiaca. El prototipo consta de un electrocardiógrafo portátil con transmisión inalámbrica y una herramienta computacional para la visualización y análisis de la señal obtenida de las derivaciones DI, DII y DIII, utilizando el método wavelets para eliminar componentes ajenas a la señal electrocardiográfica y métodos basados en derivadas para extraer las características propias de cada onda cardíaca que son introducidas a una SVM (Maquinas de Soporte Vectorial) para su posterior reconocimiento