1,979 research outputs found

    Environmental changes during secondary succession in a tropical dry forest in Mexico

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    Vegetation and environment change mutually during secondary succession, yet the idiosyncrasies of the vegetation effect on the understorey environment are poorly understood. To test whether the successional understorey environment changes predictably and is shaped by the structure and seasonality of tropical dry forests, we estimated basal area and vegetation cover, and measured understorey temperature, light and moisture conditions, in 17 plots forming a 60-y chronosequence and a mature forest. Light and air and soil temperature decreased with time (75-15% of open-sky radiation, 31.7-29.3 °C, and +2.5 °C to -0.5 °C relative to ambient, respectively), whereas relative humidity increased (67-74%). Soil water availability increased with early-successional development (-45 to -1 kPa) but decreased afterwards (to -18 kPa). The first axis of a PCA of the rainy-season environment explained 60% of the variation and was strongly related to air temperature and relative humidity. During tropical dry-forest succession, such factors may be more important than light, the reduction in which is not extreme compared with taller and more vertically stratified wet forests. Seasonality significantly affected the successional environmental gradients, which were marked mainly during the wet season. Environmental heterogeneity was higher in the wet than in the dry season, and larger for resources (light and water) than for conditions (temperature and humidity). The wet-season increase in environmental heterogeneity potentially creates differential growing scenarios; the environmental harshness of the dry season would mostly challenge seedling survival

    Planothidum audax sp. nov. (Bacillariophyta, Achnanthidiaceae), a new diatom from temporary streams in southern Portugal

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    emporary streams represent ca. half of the river network at the worldwide level, and in regions such as southern Europe their dominance of the landscape is evident (Larned et al. 2010, McDonough et al. 2011, Barbosa et al. 2020). Currently, these streams are receiving increased attention due to their importance as high diversity spots for algae, arthropods, plants, etc., and due to the ecosystem services they provide (Acuña et al. 2014, Datry et al. 2018b). Because of their geographical position and the land use changes in their watersheds (increased urbanization, agriculture, etc.), climate change, contamination and habitat fragmentation constitute forces threatening their integrity and ecological characteristics (Datry et al. 2018a, Bonada et al. 2020)

    The valuation of European financial firms

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    We extend the recent literature concerning accounting based valuation models to investigate financial firms from six European countries with substantial financial sectors: France, Germany, Italy, Netherlands, Switzerland and the UK. Not only are these crucial industries worthy of study in their own right, but unusual accounting practices, and inter-country differences in those accounting practices, provide valuable insights into the accounting-value relationship. Our sample consists of 7,714 financial firm/years observations from 1,140 companies drawn from 1989-2000. Sub-samples include 1,309 firm/years for banks, 650 for insurance companies, 1,705 for real estate firms, and 3,239 for investment companies. In most countries we find that the valuation models work as well or better in explaining cross-sectional variations in the market-to-book ratio for financial firms as they do for industrial and commercial firms in the same countries, although Switzerland is an exception to this generalization. As expected, the results are sensitive to industrial differences, accounting regulation and accounting practices. In particular, marking assets to market value reduces the relevance of earnings figures and increases that of equity

    Influence of pork liver drying on ferrochelatase activity for zinc protoporphyrin formation

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    Pork liver contains an endogenous enzyme, ferrochelatase (FeCH), which catalyses the formation of zinc protoporphyrin (ZnPP), a natural pigment of great interest for the meat industry. The aim of this study was to analyse the effect of pork liver drying (from −10 to 70 °C), as a stabilisation method, on the FeCH activity (EA) and the apparent concentration (ECapp). Drying temperatures close to room conditions (from 10 to 20 °C) allowed to preserve well the ECapp, while the EA was slightly lower (−15.2%) than in raw liver. However, when drying was conducted at extreme conditions (−10 and 70 °C), the lowest values of ECapp and EA were manifested. Therefore, the drying process at moderate temperatures close to room conditions (10 - 20 °C) was considered to be an effective method for FeCH preservation since it was possible to stabilise the liver and the loss of FeCH activity was minimised.info:eu-repo/semantics/publishedVersio

    Characterization of the transcriptome of fast and slow muscle myotomal fibres in the pacu (Piaractus mesopotamicus)

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    MDPS and EAM were supported by FAPESP, Proc. n° 12/02489-4 and 2011/09346-1. This work also received funding from CAPES, Proc. n° 2524/12. IAJ and DGDLS were supported by the Marine Alliance for Science and Technology for Scotland pooling initiative and Scottish Funding Council grant number HR09011.Background: The Pacu (Piaractus mesopotamicus) is a member of the Characiform family native to the Prata Basin (South America) and a target for the aquaculture industry. A limitation for the development of a selective breeding program for this species is a lack of available genetic information. The primary objectives of the present study were 1) to increase the genetic resources available for the species, 2) to exploit the anatomical separation of myotomal fibres types to compare the transcriptomes of slow and fast muscle phenotypes and 3) to systematically investigate the expression of Ubiquitin Specific Protease (USP) family members in fast and slow muscle in response to fasting and refeeding. Results: We generated 0.6 Tb of pair-end reads from slow and fast skeletal muscle libraries. Over 665 million reads were assembled into 504,065 contigs with an average length of 1,334 bp and N50=2,772 bp. We successfully annotated nearly 47% of the transcriptome and identified around 15,000 unique genes and over 8000 complete coding sequences. 319 KEGG metabolic pathways were also annotated and 380 putative microsatellites were identified. 956 and 604 genes were differentially expressed between slow and fast skeletal muscle, respectively. 442 paralogues pairs arising from the teleost-specific whole genome duplication were identified, with the majority showing different expression patterns between fibres types (301 in slow and 245 in fast skeletal muscle). 45 members of the USP family were identified in the transcriptome. Transcript levels were quantified by qPCR in a separate fasting and refeeding experiment. USP genes in fast muscle showed a similar transient increase in expression with fasting as the better characterized E3 ubiquitin ligases. Conclusion: We have generated a 53-fold coverage transcriptome for fast and slow myotomal muscle in the pacu (Piaractus mesopotamicus) significantly increasing the genetic resources available for this important aquaculture species. We describe significant differences in gene expression between muscle fibre types for fundamental components of general metabolism, the Pi3k/Akt/mTor network and myogenesis, including detailed analysis of paralogue expression. We also provide a comprehensive description of USP family member expression between muscle fibre types and with changing nutritional status.Publisher PDFPeer reviewe

    Ultrasound intensification of Ferrochelatase extraction from pork liver as a strategy to improve ZINC-protoporphyrin formation

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    [EN] The enzyme Ferrochelatase (FeCH), which is naturally present in pork liver, catalyses the formation of Zincprotoporphyrin (ZnPP), a natural pigment responsible for the typical color of dry-cured Italian Parma ham. The aim of this study was to evaluate the feasibility of using high power ultrasound in continuous and pulsed modes to intensify the extraction of the enzyme FeCH from pork liver. US application during FeCH extraction led to an improved enzymatic activity and further increase in the formation of ZnPP. The optimal condition tested was that of 1 min in continuous US application, in which time the enzymatic activity increased by 33.3 % compared to conventional extraction (30 min). Pulsed US application required 5 min treatments to observe a significant intensification effect. Therefore, ultrasound is a potentially feasible technique as it increases the catalytic activity of FeCH and saves time compared to the conventional extraction methodThe authors acknowledge the financial support from the "Ministerio de Economia y Competitividad (MINECO) and Instituto Nacional de Investigacion y Tecnologia Agraria y Alimentaria (INIA)" in Spain (Project RTA2017-00024-C04-03). The authors acknowledge the contribution of the undergraduate student Jose V. Pedrero-Gonzalez to the experimental work.Abril-Gisbert, B.; Sanchez-Torres, E.; Bou, R.; Garcia-Perez, J.; Benedito Fort, JJ. (2021). Ultrasound intensification of Ferrochelatase extraction from pork liver as a strategy to improve ZINC-protoporphyrin formation. Ultrasonics Sonochemistry. 78:1-7. https://doi.org/10.1016/j.ultsonch.2021.105703S177

    Compactness properties of bounded subsets of spaces of vector measure integrable functions and factorization of operators

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    [EN] Using compactness properties of bounded subsets of spaces of vector measure integrable functions and a representation theorem for q-convex Banach lattices, we prove a domination theorem for operators between Banach lattices. We generalize in this way several classical factorization results for operators between these spaces, as psumming operators.The authors acknowledge the support of the Generalitat Valenciana, Spain, grant GV04B-371, the Spanish Ministry of Science and Technology, Plan Nacional I+D+I , grant BFM2003-02302; and the support of the Universidad Polit´ecnica de Valencia, under grant 2003-4114 for Interdisciplinary Research Projects.Garcia-Raffi, LM.; Sánchez-Pérez, E. (2005). Compactness properties of bounded subsets of spaces of vector measure integrable functions and factorization of operators. Applied General Topology. 6(2):135-142. https://doi.org/10.4995/agt.2005.19521351426

    Water desorption isotherms of pork liver and thermodynamic properties

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    [EN] For the first time, the relationship between equilibrium moisture content and water activity is reported for the desorption process in pork liver. For that purpose, a standardized conductivity hygrometer was used at four different temperatures (0, 10, 30 and 50 degrees C) over a wide range of water activity (0.999-0.103). Five models frequently found in the literature (GAB, Oswin, Henderson, Hasley and Ratti) were considered for the purposes of describing the experimental desorption. The GAB model emerged as the best option (explained variance 96.6%) for the physical and mathematical description of the water desorption isotherms in pork liver. The computed isosteric heat, entropy and Gibbs energy illustrated the high water-sorbent affinity, because of a considerable availability of strong sorption sites at low moisture contents. The reported experimental desorption isotherms, and modeling results, are essentials for the optimal design of the drying process of pork liver, which is a necessary step for the further research addressing the extraction of the protein fraction from the dried product. Extraction and isolation of the protein fraction from pork liver could be considered a reasonable strategy considering the demand of protein materials and the high-environmental impact of the meat industry.The authors acknowledge the financial support from the "Ministerio de Economia y Competitividad (MINECO)" and "Instituto Nacional de Investigacion y Tecnologia Agraria y Alimentaria (INIA)" in Spain (Project RTA 2017-00024-C04-03). Eduardo A. Sanchez-Torres acknowledges the FPU PhD contract (FPU18/01439) granted by the Spanish Ministry of Science, Innovation and Universities.Sanchez-Torres, E.; Abril-Gisbert, B.; Benedito Fort, JJ.; Bon Corbín, J.; Garcia-Perez, J. (2021). Water desorption isotherms of pork liver and thermodynamic properties. LWT - Food Science and Technology. 149:1-10. https://doi.org/10.1016/j.lwt.2021.11185711014

    Cigarette Smoking Increases the Risk of Root Canal Treatment

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    Few studies have investigated smoking as a risk factor for root canal treatment. We studied the effect of smoking on the incidence of root canal treatment, controlling for recognized risk factors, in 811 dentate male participants in the VA Dental Longitudinal Study. Participants were not VA patients. Follow-up ranged from 2 to 28 years. Root canal treatment was verified on radiographs and evaluated with proportional hazards regression models. Compared with never-smokers, current cigarette smokers were 1.7 times as likely to have root canal treatment (p < 0.001), but cigar and/or pipe use was not significantly associated with root canal treatment. The risk among cigarette smokers increased with more years of exposure and decreased with length of abstinence. These findings suggest that there is a dose-response relationship between cigarette smoking and the risk of root canal treatment

    Nonlinear Realization of N=2 Superconformal Symmetry and Brane Effective Actions

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    Due to the incompatibility of the nonlinear realization of superconformal symmetry and dilatation symmetry with the dilaton as the compensator field, in the present paper it shows an alternative mechanism of spontaneous breaking the N=2 superconformal symmetry to the N=0 case. By using the approach of nonlinear transformations it is found that it leads to a space-filling brane theory with Weyl scale W(1,3) symmetry. The dynamics of the resulting Weyl scale invariant brane, along with that of other Nambu-Goldstone fields, is derived in terms of the building blocks of the vierbein and the covariant derivative from the Maurer-Cartan oneforms. A general coupling of the matter fields localized on the brane world volume to these NG fields is also constructed.Comment: 22 pages, more references and comments are adde
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