568 research outputs found

    Issue Yield and Party Strategy in Multiparty Competition

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    The issue yield model introduced a theory of the herestethic use of policy issues as strategic resources in multidimensional party competition. We extend the model by systematically addressing the specificities of issue yield dynamics in multiparty systems, with special regard to parties\u2019 issue yield rankings (relative position) and issue yield heterogeneity (differentiation) on each issue. Second, we introduce a novel research design for original data collection that allows for a more systematic testing of the model, by featuring (a) a large number of policy issues, (b) the use of Twitter content for coding parties\u2019 issue emphasis, and (c) an appropriate time sequence for measuring issue yield configurations and issue emphasis. We finally present findings from a pilot implementation of such design, performed on the occasion of the 2014 European Parliament election in Italy. Findings confirm the soundness of the design and provide support for the newly introduced hypotheses about multiparty competition

    Does higher sampling rate (multiband + SENSE) improve group statistics - An example from social neuroscience block design at 3T

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    Multiband (MB) or Simultaneous multi-slice (SMS) acquisition schemes allow the acquisition of MRI signals from more than one spatial coordinate at a time. Commercial availability has brought this technique within the reach of many neuroscientists and psychologists. Most early evaluation of the performance of MB acquisition employed resting state fMRI or the most basic tasks. In this study, we tested whether the advantages of using MB acquisition schemes generalize to group analyses using a cognitive task more representative of typical cognitive neuroscience applications. Twenty-three subjects were scanned on a Philips 3 ​T scanner using five sequences, up to eight-fold acceleration with MB-factors 1 to 4, SENSE factors up to 2 and corresponding TRs of 2.45s down to 0.63s, while they viewed (i) movie blocks showing complex actions with hand object interactions and (ii) control movie blocks without hand object interaction. Data were processed using a widely used analysis pipeline implemented in SPM12 including the unified segmentation and canonical HRF modelling. Using random effects group-level, voxel-wise analysis we found that all sequences were able to detect the basic action observation network known to be recruited by our task. The highest t-values were found for sequences with MB4 acceleration. For the MB1 sequence, a 50% bigger voxel volume was needed to reach comparable t-statistics. The group-level t-values for resting state networks (RSNs) were also highest for MB4 sequences. Here the MB1 sequence with larger voxel size did not perform comparable to the MB4 sequence. Altogether, we can thus recommend the use of MB4 (and SENSE 1.5 or 2) on a Philips scanner when aiming to perform group-level analyses using cognitive block design fMRI tasks and voxel sizes in the range of cortical thickness (e.g. 2.7 ​mm isotropic). While results will not be dramatically changed by the use of multiband, our results suggest that MB will bring a moderate but significant benefit

    La valutazione delle tecniche di difesa costiera attraverso indici di valutazione non-monetaria e monetaria.

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    The growing interest in coastal defence and initiatives against erosion consider renders increasingly important the choice of defence techniques, not only for the duration of their effects , but also for aesthetic factors and on the use of the beach for recreative, landscape and bathing purposes. This work stems from a previous analysis on the beach nourishment carried out in a bathing resort (Ladispoli) in the province of Rome, where the expense for the beach nourishment seemed acceptable, the objective now is to analyse the problem considering the aesthetic aspect. This involves consideration of the visual effect of defence structures (nourishment, breakwaters, groynes, seawalls, ecc.) measuring the visual impact of the components and comparing complex scenarios, in order to achieve a scale of aesthetic values that can be transformed in monetary values and included in the investment valuation

    Characterization of a synthetic bacterial self-destruction device for programmed cell death and for recombinant proteins release

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    <p>Abstract</p> <p>Background</p> <p>Bacterial cell lysis is a widely studied mechanism that can be achieved through the intracellular expression of phage native lytic proteins. This mechanism can be exploited for programmed cell death and for gentle cell disruption to release recombinant proteins when <it>in vivo </it>secretion is not feasible. Several genetic parts for cell lysis have been developed and their quantitative characterization is an essential step to enable the engineering of synthetic lytic systems with predictable behavior.</p> <p>Results</p> <p>Here, a BioBrick™ lysis device present in the Registry of Standard Biological Parts has been quantitatively characterized. Its activity has been measured in <it>E. coli </it>by assembling the device under the control of a well characterized N-3-oxohexanoyl-L-homoserine lactone (HSL) -inducible promoter and the transfer function, lysis dynamics, protein release capability and genotypic and phenotypic stability of the device have been evaluated. Finally, its modularity was tested by assembling the device to a different inducible promoter, which can be triggered by heat induction.</p> <p>Conclusions</p> <p>The studied device is suitable for recombinant protein release as 96% of the total amount of the intracellular proteins was successfully released into the medium. Furthermore, it has been shown that the device can be assembled to different input devices to trigger cell lysis in response to a user-defined signal. For this reason, this lysis device can be a useful tool for the rational design and construction of complex synthetic biological systems composed by biological parts with known and well characterized function. Conversely, the onset of mutants makes this device unsuitable for the programmed cell death of a bacterial population.</p

    A standard vector for the chromosomal integration and characterization of BioBrick™ parts in Escherichia coli

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    BACKGROUND: The chromosomal integration of biological parts in the host genome enables the engineering of plasmid-free stable strains with single-copy insertions of the desired gene networks. Although different integrative vectors were proposed, no standard pre-assembled genetic tool is available to carry out this task. Synthetic biology concepts can contribute to the development of standardized and user friendly solutions to easily produce engineered strains and to rapidly characterize the desired genetic parts in single-copy context. RESULTS: In this work we report the design of a novel integrative vector that allows the genomic integration of biological parts compatible with the RFC10, RFC23 and RFC12 BioBrick™ standards in Escherichia coli. It can also be specialized by using BioBrick™ parts to target the desired integration site in the host genome. The usefulness of this vector has been demonstrated by integrating a set of BioBrick™ devices in two different loci of the E. coli chromosome and by characterizing their activity in single-copy. Construct stability has also been evaluated and compared with plasmid-borne solutions. CONCLUSIONS: Physical modularity of biological parts has been successfully applied to construct a ready-to-engineer BioBrick™ vector, suitable for a stable chromosomal insertion of standard parts via the desired recombination method, i.e. the bacteriophage integration mechanism or homologous recombination. In contrast with previously proposed solutions, it is a pre-assembled vector containing properly-placed restriction sites for the direct transfer of various formats of BioBrick™ parts. This vector can facilitate the characterization of parts avoiding copy number artefacts and the construction of antibiotic resistance-free engineered microbes, suitable for industrial use

    Low-Power Ultrasounds as a Tool to Culture Human Osteoblasts inside Cancellous Hydroxyapatite

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    Bone graft substitutes and cancellous biomaterials have been widely used to heal critical-size long bone defects due to trauma, tumor resection, and tissue degeneration. In particular, porous hydroxyapatite is widely used in reconstructive bone surgery owing to its biocompatibility. In addition, the in vitro modification of cancellous hydroxyapatite with osteogenic signals enhances the tissue regeneration in vivo, suggesting that the biomaterial modification could play an important role in tissue engineering. In this study, we have followed a tissue-engineering strategy where ultrasonically stimulated SAOS-2 human osteoblasts proliferated and built their extracellular matrix inside a porous hydroxyapatite scaffold. The ultrasonic stimulus had the following parameters: average power equal to 149 mW and frequency of 1.5 MHz. In comparison with control conditions, the ultrasonic stimulus increased the cell proliferation and the surface coating with bone proteins (decorin, osteocalcin, osteopontin, type-I collagen, and type-III collagen). The mechanical stimulus aimed at obtaining a better modification of the biomaterial internal surface in terms of cell colonization and coating with bone matrix. The modified biomaterial could be used, in clinical applications, as an implant for bone repair

    Autochthonous acute hepatitis E: treatment with sofosbuvir and ribavirin

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    Introduction: Hepatitis E virus (HEV) is an emerging cause of autochthonous-acute-hepatitis and acute-on-chronic-liver-failure in western countries. Treatment is not routinely used, despite ribavirin has a good antiviral effect. In vitro sofosbuvir inhibits HEV replication, but clinical data are lacking. Case report: We report a case of acute-on-chronic-liver-failure due to HEV treated with sofosbuvir and ribavirin. The&nbsp;treatment was capable of rapidly inducing both HCV and HEV viral suppression. Conclusion: In conclusion, although more data are required before firm conclusions could be drawn, the combination of sofosbuvir and ribavirin in not immunosuppressed patients with acute hepatitis E may be able to clear HEV infection

    Cubic or Not Cubic? Combined Experimental and Computational Investigation of the Short-Range Order of Tin Halide Perovskites

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    Tin-based metal halide perovskites with a composition of ASnX3 (where A= MA or FA and X = I or Br) have been investigated by means of X-ray total scattering techniques coupled to pair distribution function (PDF) analysis. These studies revealed that that none of the four perovskites has a cubic symmetry at the local scale and that a degree of increasing distortion is always present, in particular when the cation size is increased, i.e., from MA to FA, and the hardness of the anion is increased, i.e., from Br- to I-. Electronic structure calculations provided good agreement with experimental band gaps for the four perovskites when local dynamical distortions were included in the calculations. The averaged structure obtained from molecular dynamics simulations was consistent with experimental local structures determined via X-ray PDF, thus highlighting the robustness of computational modeling and strengthening the correlation between experimental and computational results
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