49 research outputs found
Unsupervised Machine Learning and Data Mining Procedures Reveal Short Term, Climate Driven Patterns Linking Physico-Chemical Features and Zooplankton Diversity in Small Ponds
Machine Learning (ML) is an increasingly accessible discipline in computer science that develops dynamic algorithms capable of data-driven decisions and whose use in ecology is growing. Fuzzy sets are suitable descriptors of ecological communities as compared to other standard algorithms and allow the description of decisions that include elements of uncertainty and vagueness. However, fuzzy sets are scarcely applied in ecology. In this work, an unsupervised machine learning algorithm, fuzzy c-means and association rules mining were applied to assess the factors influencing the assemblage composition and distribution patterns of 12 zooplankton taxa in 24 shallow ponds in northern Italy. The fuzzy c-means algorithm was implemented to classify the ponds in terms of taxa they support, and to identify the influence of chemical and physical environmental features on the assemblage patterns. Data retrieved during 2014 and 2015 were compared, taking into account that 2014 late spring and summer air temperatures were much lower than historical records, whereas 2015 mean monthly air temperatures were much warmer than historical averages. In both years, fuzzy c-means show a strong clustering of ponds in two groups, contrasting sites characterized by different physico-chemical and biological features. Climatic anomalies, affecting the temperature regime, together with the main water supply to shallow ponds (e.g., surface runoff vs. groundwater) represent disturbance factors producing large interannual differences in the chemistry, biology and short-term dynamic of small aquatic ecosystems. Unsupervised machine learning algorithms and fuzzy sets may help in catching such apparently erratic differences
modelling the thermo mechanical behavior of a redesigned tool holder to reduce the component geometrical deviations in cryogenic machining
Abstract In recent years cryogenic cooling based on Liquid Nitrogen has been adopted to improve the titanium alloys machinability mainly in rough operations. However, when applied to semi-finishing machining, the very low temperatures may significantly affect the component final geometry. To this aim, the paper presents the thermal-mechanical modeling of a new tool holder properly designed to reduce the component geometrical deviations from its nominal geometry during cryogenic machining. The model was calibrated and validated through turning trials on wrought Ti6Al4V samples, proving a reliable prediction of the tool holder behavior during cryogenic machining
Collagen Fiber Array of Peritumoral Stroma Influences Epithelial-to-Mesenchymal Transition and Invasive Potential of Mammary Cancer Cells
: Interactions of cancer cells with matrix macromolecules of the surrounding tumor stroma are critical to mediate invasion and metastasis. In this study, we reproduced the collagen mechanical barriers in vitro (i.e., basement membrane, lamina propria under basement membrane, and deeper bundled collagen fibers with different array). These were used in 3D cell cultures to define their effects on morphology and behavior of breast cancer cells with different metastatic potential (MCF-7 and MDA-MB-231) using scanning electron microscope (SEM). We demonstrated that breast cancer cells cultured in 2D and 3D cultures on different collagen substrates show different morphologies: i) a globular/spherical shape, ii) a flattened polygonal shape, and iii) elongated/fusiform and spindle-like shapes. The distribution of different cell shapes changed with the distinct collagen fiber/fibril physical array and size. Dense collagen fibers, parallel to the culture plane, do not allow the invasion of MCF-7 and MDA-MB-231 cells, which, however, show increases of microvilli and microvesicles, respectively. These novel data highlight the regulatory role of different fibrillar collagen arrays in modifying breast cancer cell shape, inducing epithelial-to-mesenchymal transition, changing matrix composition and modulating the production of extracellular vesicles. Further investigation utilizing this in vitro model will help to demonstrate the biological roles of matrix macromolecules in cancer cell invasion in vivo
Multiparty Session Types as Coherence Proofs
We propose a Curry-Howard correspondence between a language for programming multiparty sessions and a generalisation of Classical Linear Logic (CLL). In this framework, propositions correspond to the local behaviour of a participant in a multiparty session type, proofs to processes, and proof normalisation to executing communications. Our key contribution is generalising duality, from CLL, to a new notion of n-ary compatibility, called coherence. Building on coherence as a principle of compositionality, we generalise the cut rule of CLL to a new rule for composing many processes communicating in a multiparty session. We prove the soundness of our model by showing the admissibility of our new rule, which entails deadlock-freedom via our correspondence
Oleic, Linoleic and Linolenic Acids Increase ROS Production by Fibroblasts via NADPH Oxidase Activation
The effect of oleic, linoleic and γ-linolenic acids on ROS production by 3T3 Swiss and Rat 1 fibroblasts was investigated. Using lucigenin-amplified chemiluminescence, a dose-dependent increase in extracellular superoxide levels was observed during the treatment of fibroblasts with oleic, linoleic and γ-linolenic acids. ROS production was dependent on the addition of β-NADH or NADPH to the medium. Diphenyleneiodonium inhibited the effect of oleic, linoleic and γ-linolenic acids on fibroblast superoxide release by 79%, 92% and 82%, respectively. Increased levels of p47phox phosphorylation due to fatty acid treatment were detected by Western blotting analyses of fibroblast proteins. Increased p47phox mRNA expression was observed using real-time PCR. The rank order for the fatty acid stimulation of the fibroblast oxidative burst was as follows: γ-linolenic > linoleic > oleic. In conclusion, oleic, linoleic and γ-linolenic acids stimulated ROS production via activation of the NADPH oxidase enzyme complex in fibroblasts
An Enriched European Eel Transcriptome Sheds Light upon Host-Pathogen Interactions with Vibrio vulnificus
Infectious diseases are one of the principal bottlenecks for the European eel recovery. The aim of this study was to develop a new molecular tool to be used in host-pathogen interaction experiments in the eel. To this end, we first stimulated adult eels with different pathogen-associated molecular patterns (PAMPs), extracted RNA from the immune-related tissues and sequenced the transcriptome. We obtained more than 2 x 10(6) reads that were assembled and annotated into 45,067 new descriptions with a notable representation of novel transcripts related with pathogen recognition, signal transduction and the immune response. Then, we designed a DNA-microarray that was used to analyze the early immune response against Vibrio vulnificus, a septicemic pathogen that uses the gills as the portal of entry into the blood, as well as the role of the main toxin of this species (RtxA13) on this early interaction. The gill transcriptomic profiles obtained after bath infecting eels with the wild type strain or with a mutant deficient in rtxA13 were analyzed and compared. Results demonstrate that eels react rapidly and locally against the pathogen and that this immune-response is rtxA13-dependent as transcripts related with cell destruction were highly up-regulated only in the gills from eels infected with the wild-type strain. Furthermore, significant differences in the immune response against the wild type and the mutant strain also suggest that host survival after V. vulnificus infection could depend on an efficient local phagocytic activity. Finally, we also found evidence of the presence of an interbranchial lymphoid tissue in European eel gills although further experiments will be necessary to identify such tissue
Mitochondrial Unfolded Protein Response in Arabidopsis thaliana: induction and functional characterization
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BMC 75--Nuova ed esatta Carta Della America Ricavata dale Mappe, e carte piu approvate, 1763
Map of North and South America engraved by Andrea Scacciati and published in Il Gazzettiere Americano by Marco Coltellini, Livorno, 1763. The atlas is the first Italian translation of The American Gazetteer published in 1762. The maps accompanying the atlas are derived from the French cartographer Jacques Nicolas Bellin. The works bear the signatures of Veremondo Rossi, Andrea Scacciati, Giuseppe Maria Terreni and also Violante Vanni, a rare case of Italian women\u27s engagement in the cartographic field.https://digitalmaine.com/arc_baxter/1025/thumbnail.jp
BMC 75--Nuova ed esatta Carta Della America Ricavata dale Mappe, e carte piu approvate, 1763
Map of North and South America engraved by Andrea Scacciati and published in Il Gazzettiere Americano by Marco Coltellini, Livorno, 1763. The atlas is the first Italian translation of The American Gazetteer published in 1762. The maps accompanying the atlas are derived from the French cartographer Jacques Nicolas Bellin. The works bear the signatures of Veremondo Rossi, Andrea Scacciati, Giuseppe Maria Terreni and also Violante Vanni, a rare case of Italian women\u27s engagement in the cartographic field.https://digitalmaine.com/arc_baxter/1025/thumbnail.jp
Novel spraying apparatus to investigate the lubricant deposition on metal sheets at high temperature
The constant demand of increasing performances and safety in automotive industry has led significant innovations in the materials as well as in forming processes. In particular, lightweight aluminium alloys are knowing higher and higher importance, thanks to the development of new stamping processes at high temperatures capable to allow improved formability, low spring-back and accurate micro-structural control in the formed parts. However, the choice of proper process parameters, in terms of lubrication at the interfaces between the dies and the blank, still represents a critical point for the process feasibility. On this basis, the paper aims at presenting a novel spraying apparatus to investigate the deposition of lubricants in hot stamping. The equipment allows the accurate control of the quantity of the lubricant that is deposited on the specimen and of the deposition temperature to maximize the lubricant adhesion. The results show the capability of the new equipment and the good stability of the conditions during testing