2,340 research outputs found

    Polyploid lineages in the genus Porphyra

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    Whole genome duplication is now accepted as an important evolutionary force, but the genetic factors and the life history implications affecting the existence and abundance of polyploid lineages within species are still poorly known. Polyploidy has been mainly studied in plant model species in which the sporophyte is the dominant phase in their life history. In this study, we address such questions in a novel system (Porphyra, red algae) where the gametophyte is the dominant phase in the life history. Three Porphyra species (P. dioica, P. umbilicalis, and P. linearis) were used in comparisons of ploidy levels, genome sizes and genetic differentiation using flow cytometry and 11 microsatellite markers among putative polyploid lineages. Multiple ploidy levels and genome sizes were found in Porphyra species, representing different cell lines and comprising several cytotype combinations among the same and different individuals. In P. linearis, genetic differentiation was found among three polyploid lineages: triploid, tetraploid and mixoploids, representing different evolutionary units. We conclude that the gametophytic phase (n) in Porphyra species is not haploid, contradicting previous theories. New hypotheses for the life histories of Porphyra species are discussed.FCT (Fundacao para a Ciencia e a Tecnologia, Portugal) [SFRH/BPD/109452/2015, NORIGENOMICS - PTDC/MAR/099698/2008, UID/Multi/04326/2013, BIODIVERSA/004/2015-MARFOR

    Border trees of complex networks

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    The comprehensive characterization of the structure of complex networks is essential to understand the dynamical processes which guide their evolution. The discovery of the scale-free distribution and the small world property of real networks were fundamental to stimulate more realistic models and to understand some dynamical processes such as network growth. However, properties related to the network borders (nodes with degree equal to one), one of its most fragile parts, remain little investigated and understood. The border nodes may be involved in the evolution of structures such as geographical networks. Here we analyze complex networks by looking for border trees, which are defined as the subgraphs without cycles connected to the remainder of the network (containing cycles) and terminating into border nodes. In addition to describing an algorithm for identification of such tree subgraphs, we also consider a series of their measurements, including their number of vertices, number of leaves, and depth. We investigate the properties of border trees for several theoretical models as well as real-world networks.Comment: 5 pages, 1 figure, 2 tables. A working manuscript, comments and suggestions welcome

    SDSSJ143244.91+301435.3 at VLBI: a compact radio galaxy in a narrow-line Seyfert 1

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    We present VLBI observations, carried out with the European Very Long Baseline Interferometry Network (EVN), of SDSSJ143244.91+301435.3, a radio-loud narrow-line Seyfert 1 (RLNLS1) characterized by a steep radio spectrum. The source, compact at Very Large Array (VLA) resolution, is resolved on the milliarcsec scale, showing a central region plus two extended structures. The relatively high brightness temperature of all components (5x10^6-1.3x10^8 K) supports the hypothesis that the radio emission is non-thermal and likely produced by a relativistic jet and/or small radio lobes. The observed radio morphology, the lack of a significant core and the presence of a low frequency (230 MHz) spectral turnover are reminiscent of the Compact Steep Spectrum sources (CSS). However, the linear size of the source (~0.5kpc) measured from the EVN map is lower than the value predicted using the turnover/size relation valid for CSS sources (~6kpc). This discrepancy can be explained by an additional component not detected in our observations, accounting for about a quarter of the total source flux density, combined to projection effects. The low core-dominance of the source (CD<0.29) confirms that SDSSJ143244.91+301435.3 is not a blazar, i.e. the relativistic jet is not pointing towards the observer. This supports the idea that SDSSJ143244.91+301435.3 may belong to the "parent population" of flat-spectrum RLNLS1 and favours the hypothesis of a direct link between RLNLS1 and compact, possibly young, radio galaxies.Comment: 8 pages, 3 figures, accepted for publication in MNRA

    Hybrid carcinoma of the salivary gland: salivary duct adenocarcinoma adenoid cystic carcinoma

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73933/1/j.1365-2559.1999.00761.x.pd

    Força e arquitetura muscular em sujeitos com doença arterial periférica dos membros inferiores

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    Introdução: São conhecidas as alterações da funcionalidade, nomeadamente na marcha e da função da bomba muscular da perna do indivíduo com doença arterial periférica (DAP), pelo que importa aos profissionais de saúde conhecer as alterações funcionais e estruturais associadas a esta condição. Objetivos: Avaliar a relação entre a arquitetura muscular (AM) do gémeo interno (GI), a produção de força dos músculos flexores plantares (MFP) e o índice de oclusão arterial, num grupo com DAP, comparativamente a um grupo controlo (sem DAP). Metodologia: Foram incluídos 25 sujeitos, 13 controlo e 12 com DAP, totalizando 15 pernas avaliadas por grupo, numa única sessão. A força dos MFP e amplitude de movimento da tibiotársica foram avaliadas por dinamometria isocinética (60º/s e 120º/s); a AM do GI por ultrassonografia e o índice tornozelo braço (ITB) por doppler. Foram avaliadas as diferenças entre os grupos com e sem DAP; No grupo com DAP, foram avaliadas as diferenças entre subgrupo com maior e menor severidade de oclusão (ITB<0,7 e ITB≥0,7); e foram estabelecidas correlações entre os dados de dinamometria isocinética com os da AM no grupo com DAP. Resultados: Comparado com o grupo controlo, os MFP do grupo DAP, apresentaram menores valores de momento de força máxima, momento de força máxima por unidade de peso corporal, trabalho total e potência média a 60º/s e 120º/s (P<0,05). Identificou-se, no grupo DAP ITB<0,7 menor momento de força máximo por unidade de peso corporal a 60º/s e 120º/s, comparativamente ao grupo DAP ITB≥0,7. Não se observaram diferenças entre grupo DAP e controlo na AM do GI, nem esta se relacionou com a força dos MFP ou alterada em função da gravidade da DAP. Conclusões: Sujeitos com DAP apresentam menor força dos MFP, que sujeitos sem DAP, que agrava com a severidade da obstrução arterial. Contudo, a AM do GI parece semelhante nos dois grupos, sem ter relação com a força muscular.Abstract: Introduction: The changes in functionality, namely gait and calf muscle pump function of the individual with peripheral arterial disease (PAD) are known, so it is important for health professionals to know the functional and structural changes associated with this condition. Objectives: To evaluate the relationship between gastrocnemius medialis (GM) muscle architecture, isokinetic plantar flexion strength and the lower-extremity arterial occlusion (ABI), in a group with PAD compared to a control group (without PAD). Methods: 25 individuals were included, 13 control and 12 with PAD, comprising 15 legs evaluated in each group, in a single session. Plantar flexion strength and ankle range of motion were evaluated by isokinetic dinamometry (60º/s e 120º/s); GM muscle architecture by ultrassonography and ABI by doppler. Diferences between groups with and without PAD were assessed; In PAD group, the diferences between subgroup with greater and lesser occlusion severity (ABI <0.7 and ABI≥0.7) were evaluated; and correlations were established between isokinetic dynamometry data with muscle architecture in the PAD group. Results: Compared with control group, plantar flexion muscles in PAD group presented a lower peak torque, peak torque to body weight, total work and average power at 60º/s and 120º/s (p<0,05). In a presence of a ABI<0,7, PAD group showed a lower plantar flexion peak torque to body weight for both 60º/s and 120º/s, compared with PAD group with a ABI>0,7. No associations between PAD patients and controls were found for GM architecture and these were not associated with plantar flexion isokinetic strength, or either with lower-extremity arterial haemodynamics. Conclusions: PAD subjects show lower plantar flexion muscle strength than control subjects, aggravated in the most severe cases of arterial obstruction. Nevertheless GM muscle architecture appears to be similar in both groups, with no association for plantar flexion strength or ABI.info:eu-repo/semantics/publishedVersio

    Low-power 6-bit 1-GS/s two-channel pipeline ADC with open-loop amplification using amplifiers with local-feedback

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    IEEE International Symposium on Circuits and Systems, pp. 2258 – 2261, Seattle, EUAA low-power 1.2 V 6-bit 1-GS/s time-interleaved pipeline ADC designed in 130 nm CMOS is described. It is based on a new 2-channel 1.5-bit MDAC that performs openloop residue amplification using a shared amplifier employing local-feedback. Time mismatches between channels are highly attenuated, simply by using two passive front-end Sample-and-Hold circuits, with dedicated switch-linearization control circuits, driven by a single clock phase. Simulated results of the ADC achieve 5.35-bit ENOB, with 20 mW and without requiring any gain control/calibration scheme

    The physics of intersecting thick to thin branes

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    We model four-dimensional junctions made out of intersections of co-dimension one brane living in higher-dimensional spacetimes through domain walls. We take a new look at the problem of localizing fermion states on brane junctions as a result of intersecting one thick brane to others sufficiently thin. All the branes intersect orthogonally to form a four-dimensional junction embedded in a higher-dimensional bulk. We discuss the effects of the Yukawa coupling and the proton decay on the restriction of the parameters that control the junction stability and the brane thickness which also define the bulk cosmological constant.Comment: 15 pages, 9 figure

    Produção de maxixe paulista em suporte de rede agrícola

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    Maxixe Paulista é um novo tipo de maxixe derivado originalmente do cruzamento de Cucumis anguria var. anguria x Cucumis anguria var. longaculeatus, com características distintas de fruto e folhas. Apesar das linhagens elite apresentarem comportamento semelhante em termos de produção total e peso médio de frutos, algumas características são peculiares a cada uma delas. A combinação dessas características através de produção de híbridos poderia ser uma alternativa para aumentar a qualidade e/ou a produção de frutos. O objetivo desta pesquisa foi comparar a produção de linhagens e híbridos de Maxixe Paulista cultivadas em campo, com práticas de tutoramento em rede agrícola. Foram avaliadas quatro linhagens e seis híbridos simples, quanto ao comportamento e produção de frutos no sistema de cultivo tutorado em rede agrícola. As mudas foram obtidas em bandejas de poliestireno expandido e transplantadas para linha central de canteiros de 1,20 m de largura. As plantas foram conduzidas sem poda e tutoradas em rede agrícola com malha de 0,10 x 0,10 m. O delineamento experimental foi em blocos casualizados, com quatro repetições e parcela de sete plantas. A produção foi expressa em número e massa total de frutos/parcela. Avaliaram-se características de fruto como comprimento, largura e espessura de polpa, em amostragem de cinco frutos/parcela, em duas colheitas. A produção e a qualidade dos frutos dos híbridos foram equivalentes à das linhagens. A rede agrícola se mostrou adequada para o cultivo de Maxixe Paulista na forma tutorada. Esta técnica de condução facilita a colheita e melhora a qualidade dos frutos.Paulista gherkin is a new gherkin type obtained by crossing Cucumis anguria var. anguria x C. anguria var. longaculeatus. It differs from common gherkin in its fruits and leaves. Elite lines of Paulista gherkin present similar performance for total yield and fruit weight but some have distinctive characteristics, including fruit and leaf attributes. The combination of these characteristics through production of Paulista gherkin hybrids could be an alternative for fruit quality and/or yield improvement. The purpose of the present work was to compare the yield of Paulista gherkin lines and their hybrids grown on a trellis net under field conditions. Four lines and their six single-cross hybrids were evaluated for yield and fruit production using the trellised net production system. Seedlings were produced in polystyrene trays with 128 cells, and transplanted to the middle of 1.20 m wide beds. Plants were trained without pruning on netting having 0.1 x 0.1 m openings. The experiment was conducted in a randomized block design with four replicates and seven plants per plot. Yield was expressed as number of fruits and total weight of fruits per plot. Length, width and fruit flesh thickness were also evaluated, with five samples per plot in two harvesting times. Hybrids and their parental lines were similar in fruit yield and quality. The trellised net was suitable for Paulista gherkin production and provided adequate support to the plants. The trellis technique is suitable to make harvesting easier and to improve fruit quality
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