541 research outputs found
Partition Functions of Pure Spinors
We compute partition functions describing multiplicities and charges of
massless and first massive string states of pure-spinor superstrings in
3,4,6,10 dimensions. At the massless level we find a spin-one gauge multiplet
of minimal supersymmetry in d dimensions. At the first massive string level we
find a massive spin-two multiplet. The result is confirmed by a direct analysis
of the BRST cohomology at ghost number one. The central charges of the pure
spinor systems are derived in a manifestly SO(d) covariant way confirming that
the resulting string theories are critical. A critical string model with
N=(2,0) supersymmetry in d=2 is also described.Comment: LaTex, 30 p
The effect of temperature on mobility of Angiostrongylus costaricensis third stage larvae
The role of associated bacteria in explaining adaptation by the vine weevil Otiorhynchussulcatus(Fabricius) to different environments
The vine weevil Otiorhynchus sulcatus(Fabricius)is a curculionid pest endemic to central Europe which has successfully invaded regions on nearly all continents. This weevil species is characterised by an ability to feed on a broad range of plant species, several of which are grown as horticultural crops. Research investigating the distinctiveness of insects inhabiting separate geographic areas or infesting different crop species is still scant. Genetically, vine weevils from different locations have been shown to display limited genomic differences. The research presented here further investigated if features other than insect genetic variation are distinct amongst vine weevil populations found at different locations. The bacterial community of adult vine weevils from different populations found at geographically distinct locations within the UK but from the same host plant species was characterised. Additionally, some of these populations were tested for variation in susceptibility to a fungal pathogen commonly included in control strategies targeting this pest, Metarhizium brunneum(Petch.Oviposition choice was also examined on these insects between two host plant species susceptible to vine weevil infestation, strawberry and raspberry. Additionally, the fluctuation in titre of the bacterium Candidatus Nardonella during vine weevil development was assessed. This prokaryote was shown to dominate the bacterial community of the vine weevil and so we aimed at identifying important functions for its host.Insect population source per se did not shape the bacterial microbiota or influence the insect fitness parameters measured. Ca.Nardonella abundance followed a pattern which may indicate its involvement in tyrosine metabolism and cuticle formation.Future research should investigate vine weevils from a wider selection of geographic locations including non-crop environments to complete this line of research. Additionally, the influence of the host plant species on the distinctiveness of vine weevil populations should also be tested. Ca. Nardonella has been shown to play important roles for other weevils. Hence, the function of this bacterium for the vine weevil deserves further attention
Comparison between conjugated linoleic acid and essential fatty acids in preventing oxidative stress in bovine mammary epithelial cells
Some in vitro and in vivo studies have demonstrated protective effects of conjugated linoleic acid (CLA) isomers against oxidative stress and lipid peroxidation. However, only a few and conflicting studies have been conducted showing the antioxidant potential of essential fatty acids. The objectives of the study were to compare the effects of CLA to other essential fatty acids on the thiol redox status of bovine mammary epithelia cells (BME-UV1) and their protective role against oxidative damage on the mammary gland by an in vitro study. The BME-UV1 cells were treated with complete medium containing 50 μM of cis-9,trans-11 CLA, trans-10,cis-12 CLA, α-linolenic acid, γ-linolenic acid, and linoleic acid. To assess the cellular antioxidant response, glutathione, NADPH, and γ-glutamyl-cysteine ligase activity were measured 48 h after addition of fatty acids (FA). Intracellular reactive oxygen species and malondialdehyde production were also assessed in cells supplemented with FA. Reactive oxygen species production after 3 h of H2O2 exposure was assessed to evaluate and to compare the potential protection of different FA against H2O2-induced oxidative stress. All FA treatments induced an intracellular GSH increase, matched by high concentrations of NADPH and an increase of γ-glutamyl-cysteine ligase activity. Cells supplemented with FA showed a reduction in intracellular malondialdehyde levels. In particular, CLA isomers and linoleic acid supplementation showed a better antioxidant cellular response against oxidative damage induced by H2O2 compared with other FA
Heat shock induced changes of adipokines gene expression in 3T3-L1 adipocytes
To study the effects of heat shock on adipokines gene expression 3T3-L1 adipocytes were used. Heat shock differently affected gene expression of leptin, adiponectin and acylation stimulating protein (ASP): exposure of cells to temperature higher than 39°C caused upregulation of leptin and downregulation of adiponectin and ASP genes. The present study provides the first evidence about the effects of heat shock on adipokines gene expression. Changes in gene expression of the three adipokines may help to explain the alteration of lipid metabolism and liver functionality occurring in animals exposed to hot conditions
Lactobacillus rhamnosus GG and Saccharomyces cerevisiae boulardii exert synergistic antipathogenic activity in vitro against enterotoxigenic Escherichia coli
Short-term colonic in vitro batch incubations were performed to elucidate the possible synergistic effects of Lactobacillus rhamnosus GG (CNCM-I-4798) and Saccharomyces cerevisiae boulardii (CNCM-1-1079) (associated in Smebiocta/Smectaflora Protect (R)) on the colonic microbial fermentation process, as well as their antipathogenic activity against enterotoxigenic Escherichia coli (LMG2092) (ETEC). These incubations adequately simulate the native microbiota and environmental conditions of the proximal colon of both adult and toddler donors, including the colonic mucosal layer. Results indicated that both strains were capable of growing together without showing antagonistic effects. Co-cultivation of both strains resulted in increased butyrate (stimulated by L. rhamnosus GG), propionate (stimulated by S. boulardii), and ethanol (produced by S. boulardii) production compared to the control incubations, revealing the additive effect of both strains. After inoculation of ETEC under simulated dysbiotic conditions, a 40 and 46% reduction in the concentration of ETEC was observed upon addition of both strains during the experiments with the adult and toddler donor, respectively. Furthermore, ETEC toxin levels decreased upon S. boulardii inoculation, probably due to proteolytic activity of this strain, with a synergistic effect being observed upon co-cultivation of L. rhamnosus GG and S. boulardii resulting in a reduction of 57 and 46% for the adult and toddler donor, respectively. Altogether, the results suggest that both probiotics together may help microbiota functionality, in both adults and toddlers and under healthy or impaired conditions, which could be of great interest when the colonic microbiota is dysbiotic and therefore sensitive to pathogenic invasion such as during antibiotic treatment
Human infection by Angiostrongylus costaricensis in Venezuela: first report of a confirmed case
The use of straw mulch as a strategy to prevent extreme soil erosion rates in citrus orchard. A Rainfall simulation approach
Not only the Sahel (Haregeweyn et al., 2013), the deforested land (Borelli et al., 2013) the chinese Plateau are
affected by intense soil erosion rates (Zhao et al., 2013). Soil erosion affect agriculture land (CerdĂ et al., 2009),
and citrus orchards are being seeing as one of the crops with the highest erosion rates due to the managements
that avoid the catch crops, weeds or litter. Example of the research carried out on citrus orchards is found in the
Mediterranean (CerdĂ and Jurgensen, 2008; 2009; CerdĂ et al., 2009a; 2009b; CerdĂ et al., 2011; 2012) and in
China (Wu et al., 1997; Xu et al., 2010; Wang et al., 2011; Wu et al., 2011; Liu et al., 2011; LĂĽ et al., 2011; Xu et
al., 2012), and they confirm the non sustainable soil losses measured. The land management in citrus plantations
results in soil degradation too (Lu et al., 1997; LĂĽ et al., 2012; Xu et al., 2012). The use of cover crops to reduce
the soil losses (Lavigne et al., 2012; Le Bellec et al., 2012) and the use of residues such as dried citrus peel has
been found successful. There is a need to find new plants or residues to protect the soils on citrus orchards.
Agriculture produces a high amount of residues. The pruning can contribute with a valuable source of nutrients
and a good soil protection. The leaves of the trees, and some parts of the plants, once harvest can contribute to
reduce the soil losses. Due to the mechanization of the agriculture, and the reduction of the draft animals (mainly
horses, mules, donkeys and oxen) the straw is being a residue instead of a resource. The Valencia region is the
largest producer of citrus in Europe, and the largest exporter in the world. This citrus production region is located
in the eastern cost of Spain where we can find the rice production area of the l’Albufera Lagoon paddy fields,
the third largest production region in Spain. This means, a rice production region surrounded by the huge citrus
production region. There, the rice straw is not used in the paddy fields after harvesting and the straw is being as
a residue that damages the air quality when burnt, the water quality due to the decomposition and the methane
production, and is not accepted in the field by the farmers. This is a new problem as few years ago the rice straw
was use for animal feeding. Many attempts were developed in the last decade to remove and use the straw to avoid
fires and water pollution (Iranzo et al., 2004; Silvestre et al., 2013).
Our goal is to test if a residue such as the rice straw can be transformed as a resource: soil erosion control. Straw
has been seen as a very efficient to reduce the water losses in agriculture land (GarcĂa Moreno et al., 2013), the
soil losses in fire affected land (Robichaud et al., 2013a; 2013b; Fernandez and Vega, 2014), and soil properties
(GarcĂa Orenes et al., 2009; 2010; Jordán et al., 2010; GarcĂa Orenes 2012).
Rainfall simulations under 55 mm h-1 rainfall intensity during one hour on 0,25 m2 plots were carried out on plots
paired plots: bare and covered with straw. The plots covered with straw had different straw mulch cover: from 10
to 100 % cover and from 0,005 g m2 to 300 g m2. The results show a positive effect of the straw cover that show
an exponential relation between the straw cover and weight with the sediment yield.
Acknowledgements
The research projects GL2008-02879/BTE, LEDDRA 243857 and RECARE supported this research
Angiostrongylus costaricensis: complete redescription of the migratory pathways based on experimental Sigmodon hispidus infection
- …