Evolution of Collaborative Networks Supporting Startup Sustainability: Evidences from Digital Firms

The aim of this paper is to investigate whether startup evolution can be conceptualized in a life cycle model intended as an unpredictable sequence of stages, where startups need to find actors with whom to collaborate to acquire knowledge and resources supporting the effectiveness and the sustainability of their mission. The creation and implementation of collaborative networks is observed through the lens of the holistic approach to the entrepreneurial ecosystem, whose purpose is to build “bridges” between different actors through the creation of communities of best practices or entrepreneurial networks. The creation of a specific ecosystem is suggested to ease the new digital entrepreneurship generation toward acquiring an appropriate level of knowledge, skills, financial facilitations, and entrepreneurial culture. Following a multiple case study analysis based on nine successful Italian digital firms, the empirical evidence seems to confirm that firms collaborate with different actors in different stages, as knowledge and resource networks play a critical role in sustaining the evolution and success of new firms

Molecular characterization of 18S rDNA partial sequence in Microcosmus (Stolidobranchiata, Pyuridae)

We present a 18S rDNA based molecular phylogeny of two species of the genus Microcosmus (M. sulcatus and M. claudicans) sampled in the Mediterranean, to investigate their phylogenetic position relative to species of the order Stolidobranchiata. The analysis is based on partial sequences (739 bp) of the 18S rDNA. Among the 18 variable sites found between the two species, 4 correspond to transitions (ts), 14 to transversions (tv) and 4 to deletions/insertions. In the considered Stolidobranchiata, we found 4.3% overall mean number of nucleotide differences and 0.06 (S.E. ±0.01) Kimura 2-parameter distance. The mean number of nucleotide differences between Microcosmus spp. and other Stolidobranchiata species was of 6% and 0.08 (S.E. ±0.01) Kimura 2-parameter distance. A molecular phylogeny obtained by Maximum Parsimony corroborates results of the traditional taxonomy

Photonic crystal electrode to be used in organic LED structures

In this work we report the possibility to obtain a high refractive index grid anode directly on the substrate surface by fabricating a relatively large-area photonic crystal (PC) structure using the combinations of electron beam lithography (EBL) and focused ion beam (FIB) techniques. The performance of the realized photonic crystal (PC) structure were enhanced by milling the ITO layer until the glass substrate and by removing the further refractive index jump between the PC and the substrate. The good properties of highly conductive poly(3,4 ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS), ensured a continuous path for the current and a high refractive index jump for the PC structure by filling the holes in the PC structure

A discrete Laplace-Beltrami operator for simplicial surfaces

We define a discrete Laplace-Beltrami operator for simplicial surfaces. It depends only on the intrinsic geometry of the surface and its edge weights are positive. Our Laplace operator is similar to the well known finite-elements Laplacian (the so called ``cotan formula'') except that it is based on the intrinsic Delaunay triangulation of the simplicial surface. This leads to new definitions of discrete harmonic functions, discrete mean curvature, and discrete minimal surfaces. The definition of the discrete Laplace-Beltrami operator depends on the existence and uniqueness of Delaunay tessellations in piecewise flat surfaces. While the existence is known, we prove the uniqueness. Using Rippa's Theorem we show that, as claimed, Musin's harmonic index provides an optimality criterion for Delaunay triangulations, and this can be used to prove that the edge flipping algorithm terminates also in the setting of piecewise flat surfaces.Comment: 18 pages, 6 vector graphics figures. v2: Section 2 on Delaunay triangulations of piecewise flat surfaces revised and expanded. References added. Some minor changes, typos corrected. v3: fixed inaccuracies in discussion of flip algorithm, corrected attributions, added references, some minor revision to improve expositio

Laser-tissue photothermal interaction: a thermal infrared imaging study

A 2-D approach, based on Infrared (IR) imaging for monitoring and optimizing the photo-therapy in dermatology, is proposed. We studied the possibility to employ IR imaging in order to select the laser treatment parameters for each patient. A Pulsed Thermography (PT) model allowed to evaluate morphological information on the specific area to treat after a single laser pulse test. The data were elaborated through a 2-D numerical simulation, which described the tissue temperature profiles for different sets of laser parameters. Based on this approach, it was possible to select the laser parameters according to specific pathology, morphology and phototype in order to achieve the best performances in the phototherapy practice

The effect of carnitine on Arabidopsis development and recovery in salt stress conditions

Carnitine exists in all living organisms where it plays diverse roles. In animals and yeast, it is implicated in lipid metabolism and is also associated with oxidative stress tolerance. In bacteria, it is a major player in osmotic stress tolerance. We investigate the carnitine function in plants and our present work shows that carnitine enhances the development and recovery of Arabidopsis thaliana seedlings subjected to salt stress. Biological data show that exogenous carnitine supplies improve the germination and survival rates of seedlings grown on salt-enriched medium, in a manner comparable to proline. Both compounds are shown to improve seedling survival under oxidative constraint meaning that they may act on salt stress through antioxidant properties. A transcriptome analysis of seedlings treated with exogenous carnitine reveals that it modulates the expression of genes involved in water stress and abscisic acid responses. Analyses of the abscisic acid mutants, aba1-1 and abi1-1, indicate that carnitine and proline may act through a modulation of the ABA pathway

Gout and kidney during XVII and XIX centuries

The authors briefly describe the history of gout, mainly focusing their attention on the renal involvement. They report some works and theories on gout of great ancient physicians, such as Paracelsus, Sydenham, Boerhaave, Van Swieten and Morgagni

Photonic crystal electrode to be used in organic LED structures

In this work we report the possibility to obtain a high refractive index grid anode directly on the substrate surface by fabricating a relatively large-area photonic crystal (PC) structure using the combinations of electron beam lithography (EBL) and focused ion beam (FIB) techniques. The performance of the realized photonic crystal (PC) structure were enhanced by milling the ITO layer until the glass substrate and by removing the further refractive index jump between the PC and the substrate. The good properties of highly conductive poly(3,4 ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS), ensured a continuous path for the current and a high refractive index jump for the PC structure by filling the holes in the PC structure

Flavin-Induced Oligomerization in Escherichia coli Adaptive Response Protein AidB

The process known as “adaptive response” allows Escherichia coli to respond to small doses of DNA-methylating agents by upregulating the expression of four proteins. While the role of three of these proteins in mitigating DNA damage is well understood, the function of AidB is less clear. Although AidB is a flavoprotein, no catalytic role has been established for the bound cofactor. Here we investigate the possibility that flavin plays a structural role in the assembly of the AidB tetramer. We report the generation and biophysical characterization of deflavinated AidB and of an AidB mutant that has greatly reduced affinity for flavin adenine dinucleotide (FAD). Using fluorescence quenching and analytical ultracentrifugation, we find that apo AidB has a high affinity for FAD, as indicated by an apparent dissociation constant of 402.1 ± 35.1 nM, and that binding of substoichiometric amounts of FAD triggers a transition in the AidB oligomeric state. In particular, deflavinated AidB is dimeric, whereas the addition of FAD yields a tetramer. We further investigate the dimerization and tetramerization interfaces of AidB by determining a 2.8 Å resolution crystal structure in space group P32 that contains three intact tetramers in the asymmetric unit. Taken together, our findings provide strong evidence that FAD plays a structural role in the formation of tetrameric AidB.National Institutes of Health (U.S.) (grant R01-GM0272663)National Institutes of Health (U.S.) (grant P30-ES002109)National Science Foundation (U.S.) (grant MCB-0543833