605 research outputs found
Effectiveness of distributed temperature measurements for early detection of piping in river embankments
Abstract. Internal erosion is the cause of a significant percentage of failure and
incidents involving both dams and river embankments in many countries. In the
past 20 years the use of fibre-optic Distributed Temperature Sensing (DTS) in
dams has proved to be an effective tool for the detection of leakages and
internal erosion. This work investigates the effectiveness of DTS for dike
monitoring, focusing on the early detection of backward erosion piping, a
mechanism that affects the foundation layer of structures resting on
permeable, sandy soils. The paper presents data from a piping test performed
on a large-scale experimental dike equipped with a DTS system together with a
large number of accompanying sensors. The effect of seepage and piping on the
temperature field is analysed, eventually identifying the processes that
cause the onset of thermal anomalies around piping channels and thus enable
their early detection. Making use of dimensional analysis, the factors that
influence this thermal response of a dike foundation are identified. Finally
some tools are provided that can be helpful for the design of monitoring
systems and for the interpretation of temperature data
UNRAVELING THE ROLE OF BPC PROTEINS IN INFLORESCENCE AND FLOWER DEVELOPMENT IN A. THALIANA
BPC proteins belong to a small plant specific family of transcription factors and they share functional similarities with the GAGA ASSOCIATED FACTOR (GAF) of Drosophila melanogaster. In Arabidopsis thaliana, there are seven BPs genes, although BPC5 is considered a pseudogene. Except BPC5, BPC genes are ubiquitously expressed in all plant tissues throughout development and this overlap in expression could suggest that BPCs act redundantly. The C-terminal domain of BPC proteins facilitates binding to DNA at GA-rich sequences and for BPC1, a consensus binding site has been proposed. However, little is known about their function in gene regulation and INNER NO OUTER, SEEDSTICK and LEAFY COTYLEDON2 are the only BPC target genes identified until now. To study BPC function in vivo, we have now constructed bpc1 bpc2 bpc3 triple mutants, which develop inflorescences comprising more flowers than wild-type plants, their phyllotaxis is altered and flowers develop extra floral organs. These features could be linked to meristem size and activity: it is well known that plants with bigger and/or more active meristems produce higher number of flowers and floral organs respect to wild-type. An involvement of BPC regulators in meristem maintenance has not been uncovered yet, however the BBR factor (the BPC homolog in barley) binds and regulates the BKN3 gene, the barley homolog of Arabidopsis SHOOTMERISTEMLESS (STM). In Arabidopsis, STM is involved in meristem maintenance and activity and it is also involved in the cytokinin pathway, a class of plant hormones able to promote shoot meristem growth and maintenance. These data made it interesting to investigate the involvement of BPCs and their role in the cytokinin pathway
Schema-agnostic progressive entity resolution
Entity Resolution (ER) is the task of finding entity profiles that correspond to the same real-world entity. Progressive ER aims to efficiently resolve large datasets when limited time and/or computational resources are available. In practice, its goal is to provide the best possible partial solution by approximating the optimal comparison order of the entity profiles. So far, Progressive ER has only been examined in the context of structured (relational) data sources, as the existing methods rely on schema knowledge to save unnecessary comparisons: they restrict their search space to similar entities with the help of schema-based blocking keys (i.e., signatures that represent the entity profiles). As a result, these solutions are not applicable in Big Data integration applications, which involve large and heterogeneous datasets, such as relational and RDF databases, JSON files, Web corpus etc. To cover this gap, we propose a family of schema-agnostic Progressive ER methods, which do not require schema information, thus applying to heterogeneous data sources of any schema variety. First, we introduce two na\uefve schema-agnostic methods, showing that straightforward solutions exhibit a poor performance that does not scale well to large volumes of data. Then, we propose four different advanced methods. Through an extensive experimental evaluation over 7 real-world, established datasets, we show that all the advanced methods outperform to a significant extent both the na\uefve and the state-of-the-art schema-based ones. We also investigate the relative performance of the advanced methods, providing guidelines on the method selection
Ecotoxicity of hallachrome, an unusual 1-2 anthraquinone excreted by the infaunal polychaete Halla parthenopeia: evidence for a chemical defence?
Polychaetes play a prominent role in marine systems, but little is known about their secondary metabolites compared with other benthic taxa. In the present study, we investigated the toxicity of hallachrome, an unusual 1-2 anthraquinone identified from the skin of some polychaetes, including the Mediterranean infaunal species Halla parthenopeia. Under stress conditions, this worm releases a harmful purple mucus, whose noxious compounds were still unknown. We hypothesized that hallachrome also occurs in the purple mucus, giving rise to its color and toxicity. Soon after the production of the purple exudate, H. parthenopeia also secretes a harmless, transparent mucus, which pushes away the toxic one, suggesting protective functions for the worm itself. LC-MS and H-1-NMR analyses confirmed the presence of the pigment hallachrome in the purple mucus. The average concentration of the pigment in the purple mucus was about 310 mg L-1. Ecotoxicological bioassays on representative species of bacteria, protozoans, rotifers, crustaceans (Artemia franciscana) and polychaetes (Dinophilus gyrociliatus) revealed its severe toxic effects: LC50/EC(50)values ranged from 0.11-5.67 mg L-1. Hallachrome showed higher toxicity for A. franciscana than other naturally occurring anthraquinones. Tests on encapsulated embryos of D. gyrociliatus evidenced the ability of a mucus layer to limit hallachrome diffusion, confirming the protective role of the transparent mucus. Given the information available on polychaetes anti-predator strategies, hallachrome cannot be considered a consumer deterrent. However its toxicity and wide range of activity suggest chemical defensive functions against potential competitors, parasites and/or pathogens
Class I BASIC PENTACYSTEINE factors regulate HOMEOBOX genes involved in meristem size maintenance
The BASIC PENTACYSTEINE (BCP) family is a poorly characterized plant transcription factor family of GAGA BINDING PROTEINS. In Arabidopsis, there are seven members (BPC1-7) that are broadly expressed, and they can potentially bind more than 3000 Arabidopsis GAGA-repeat-containing genes. To date, BPCs are known to be direct regulators of the INNER NO OUTER (INO), SEEDSTICK (STK), and LEAFY COTYLEDON 2 (LEC2) genes. Because of the high functional redundancy, neither single knockout nor double bpc mutant combinations cause aberrant phenotypes. The bpc1-2 bpc2 bpc3 triple mutant shows several pleiotropic developmental defects, including enlargement of the inflorescence meristem and flowers with supernumerary floral organs. Here, we demonstrated through expression analysis and chromatin immunoprecipitation assays that this phenotype is probably due to deregulation of the expression of the SHOOTMERISTEMLESS (STM) and BREVIPEDICELLUS/KNAT1 (BP) genes, which are both direct targets of BPCs. Moreover, we assigned a role to BPCs in the fine regulation of the cytokinin content in the meristem, as both ISOPENTENYLTRANSFERASE 7 (IPT7) and ARABIDOPSIS RESPONSE REGULATOR 7 (ARR7) genes were shown to be overexpressed in the bpc1-2 bpc2 bpc3 triple mutant
Potentialities of the combined use of underwater fluorescence imagery and photogrammetry for the detection of fine-scale changes in marine bioconstructors
Marine communities are facing both natural disturbances and anthropogenic stressors. Bioconstructor species are endangered by multiple large-scale and local pressures and the early identification of impacts and damages is a primary goal for preserving coral reefs. Taking advantage of the recent development in underwater photogrammetry, the use of photogrammetry and fluorimetry was coupled to design, test and validate in laboratory a multi-sensor measuring system that could be potentially exploited in open water by SCUBA divers for assessing the health status of corals and detecting relevant biometric parameters with high accuracy and resolution. The approach was tested with fragments of the endemic coral Cladocora caespitosa, the sole zooxanthellate scleractinian reef-builder in the Mediterranean. The most significant results contributing to the scientific advancement of knowledge were: 1) the development of a cost-effective, flexible and easy-to-use approach based on emerging technologies; 2) the achievement of a sub-centimetric resolution for measuring relevant biometric parameters (polyp counting, colony surface areas and volumes); 3) set up of a reliable and repeatable strategy for multi-temporal analyses capable of quantifying changes in coral morphology with sub-centimeter accuracy; 4) detect changes in coral health status at a fine scale and under natural lighting through autofluorescence analysis. The novelty of the present research lies in the coupling of emerging techniques that could be applied to a wide range of 3D morphometrics, different habitats and species, thus paving the way to innovative opportunities in ecological research and more effective results than traditional in-situ measurements. Moreover, the possibility to easily modify the developed system to be installed on an underwater remotely operated vehicle further highlights the possible concrete impact of the research for ecological monitoring and protection purposes
NEW SECONDARY METABOLITES IN THE AMPHINOMID FIREWORM HERMODICE CARUNCULATA
Eight betaine-derived novel compounds were found in extracts of the Mediterranean stinging fireworm Hermodice carunculata. The identification of their
structures relies on 1D and 2D NMR (Fig. 1-3) and HPLC-ESI/HRMS spectra. Two types of terminal ammonium portions A and B and a series of different alkyl
chains were identified (Fig. 4a,b). Their matching provides the structures of uncharacterized secondary metabolites, named carunculines, and their related
isomers. These molecules differ from already known trimethylammonium inflammatory compounds (i.e. complanines) isolated from another amphinomid
species, for the structures of the terminal ammonium groups (Fig. 4c) [1]. Carunculine anatomical distribution within H. carunculata was assessed by
screening through HPLC-ESI/HRMS (Fig. 5, Table 1): their occurrence was revealed in all the body parts analyzed, both involved in predator-prey interactions
[2], and mainly in the digestive apparatus. The results achieved reveal an array of different novel compounds from a chemically unknown species, improving
knowledge on Marine Animal Products with chemical and biological potential for bioprospection [3]. Overall, these data reinforce the necessity of studying
poorly-investigated taxa to expand knowledge on animal venom biology, their mechanisms of action and exploitation as promising source of drug molecule
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