On low-frequency unsteadiness in swept shock wave–boundary layer interactions

We derive a scaling law for the characteristic frequencies of wall pressure fluctuations in swept shock wave/turbulent boundary layer interactions in the presence of cylindrical symmetry, based on analysis of a direct numerical simulations database. Direct numerical simulations in large domains show evidence of spanwise rippling of the separation line, with typical wavelength proportional to separation bubble size. Pressure disturbances around the separation line are shown to be convected at a phase speed proportional to the cross-flow velocity. This information is leveraged to derive a simple model for low-frequency unsteadiness, which extends previous two-dimensional models (Piponniau et al., J. Fluid Mech., vol. 629, 2009, pp. 87–108), and which correctly predicts growth of the typical frequency with the sweep angle. Inferences regarding the typical frequencies in more general swept shock wave/turbulent boundary layer interactions are also discussed

Multicomponent force transducer calibration procedure using tilted plates

The calibration of a multicomponent force transducers (MFTs)represents a challenge in the meganewtonrange. In fact,the generation of transversal forces and moments iscomplex since a force standard machine (FSM) is only able to apply an uniaxial force. Furthermore since MFTs are composed of multi-transducers, each one dedicated to a particular component, correlations between force and moment componentsare possible. Therefore, acalibration systemthat could simultaneously generate all force/moment components and could be suitableinevery FSMis needed. For this purpose, a coupleof tilted plates was designed. Calibration measurements were performed on a 2 MN MFT at INRiM, LNE and PTB. Exploitation matrixes and performance indicators showed good results, unless small but not negligible correlations between MFT outputs. In particularsome spurious valuesdue to the uncertainty inthe vertical force application pointinfluencedthe moment components

Genomics of flower identity in grapevine (Vitis vinifera L.)

The identity of the four characteristic whorls of typical eudicots, namely, sepals, petals, stamens, and carpels, is specified by the overlapping action of homeotic genes, whose single and combined contributions have been described in detail in the so-called ABCDE model. Continuous species-specific refinements and translations resulted in this model providing the basis for understanding the genetic and molecular mechanisms of flower development in model organisms, such as Arabidopsis thaliana and other main plant species. Although grapevine (Vitis vinifera L.) represents an extremely important cultivated fruit crop globally, studies related to the genetic determinism of flower development are still rare, probably because of the limited interest in sexual reproduction in a plant that is predominantly propagated asexually. Nonetheless, several studies have identified and functionally characterized some ABCDE orthologs in grapevine. The present study is intended to provide a comprehensive screenshot of the transcriptional behavior of 18 representative grapevine ABCDE genes encoding MADS-box transcription factors in a developmental kinetic process, from preanthesis to the postfertilization stage and in different flower organs, namely, the calyx, calyptra, anthers, filaments, ovary, and embryos. The transcript levels found were compared with the proposed model for Arabidopsis to evaluate their biological consistency. With a few exceptions, the results confirmed the expression pattern expected based on the Arabidopsis data

Selection rules for the orbital angular momentum of optically-produced THz radiation

In this work we theoretically study the transduction ofthe Orbital Angular Momentum (OAM)lfor infraredpump lasers into the THz domain. In the case of opti-cal rectification, the transduction of OAM occurs onlythrough a spin-orbit interaction, with the selection ruleon the OAMl=0valid for any kind of polarizationof the pump, which means that there is no transfer ofOAM along the propagation axis. In the difference fre-quency generation the selection rule for the difference∆lbetween the OAM of the pump fields with linear orcircular polarization isl=∆l, whereaslranges from∆l−2to∆l+2in both the cases of radial and azimuthalpolarization. Moreover, for THz generation in the lat-ter case, high diffraction obtained with tightly focusedpumps yieldsltending to∆l±2, whileltends to zeroin the opposite case of large pump beam

The leaf transcriptome of fennel (Foeniculum vulgare Mill.) enables characterization of the t-anethole pathway and the discovery of microsatellites and single-nucleotide variants

Fennel is a plant species of both agronomic and pharmaceutical interest that is characterized by a shortage of genetic and molecular data. Taking advantage of NGS technology, we sequenced and annotated the first fennel leaf transcriptome using material from four different lines and two different bioinformatic approaches: de novo and genome-guided transcriptome assembly. A reference transcriptome for assembly was produced by combining these two approaches. Among the 79,263 transcripts obtained, 47,775 were annotated using BLASTX analysis performed against the NR protein database subset with 11,853 transcripts representing putative full-length CDS. Bioinformatic analyses revealed 1,011 transcripts encoding transcription factors, mainly from the BHLH, MYB-related, C2H2, MYB, and ERF families, and 6,411 EST-SSR regions. Single-nucleotide variants of SNPs and indels were identified among the 8 samples at a frequency of 0.5 and 0.04 variants per Kb, respectively. Finally, the assembled transcripts were screened to identify genes related to the biosynthesis of t-anethole, a compound well-known for its nutraceutical and medical properties. For each of the 11 genes encoding structural enzymes in the t-anethole biosynthetic pathway, we identified at least one transcript showing a significant match. Overall, our work represents a treasure trove of information exploitable both for marker-assisted breeding and for in-depth studies on thousands of genes, including those involved in t-anethole biosynthesis

Metabolic pathways variability and sequence/networks comparisons

BACKGROUND: In this work a simple method for the computation of relative similarities between homologous metabolic network modules is presented. The method is similar to classical sequence alignment and allows for the generation of phenotypic trees amenable to be compared with correspondent sequence based trees. The procedure can be applied to both single metabolic modules and whole metabolic network data without the need of any specific assumption. RESULTS: We demonstrate both the ability of the proposed method to build reliable biological classification of a set of microrganisms and the strong correlation between the metabolic network wiringand involved enzymes sequence space. CONCLUSION: The method represents a valuable tool for the investigation of genotype/phenotype correlationsallowing for a direct comparison of different species as for their metabolic machinery. In addition the detection of enzymes whose sequence space is maximally correlated with the metabolicnetwork space gives an indication of the most crucial (on an evolutionary viewpoint) steps of the metabolic process

On a stochastic approach to model the double phosphorylation/dephosphorylation cycle

Because of the unavoidable intrinsic noise affecting biochemical processes, astochastic approach is usually preferred whenever a deterministic model givestoo rough information or, worse, may lead to erroneous qualitative behaviorsand/or quantitatively wrong results. In this work we focus on the chemicalmaster equation (CME)-based method which provides an accurate stochasticdescription of complex biochemical reaction networks in terms of the probabilitydistribution of the underlying chemical populations. Indeed, deterministic mod-els can be dealt with as first-order approximations of the average-value dynamicscoming from the stochastic CME approach. Here we investigate the double phos-phorylation/dephosphorylation cycle, a well-studied enzymatic reaction networkwhere the inherent double time scale requires one to exploit quasisteady stateapproximation (QSSA) approaches to infer qualitative and quantitative informa-tion. Within the deterministic realm, several researchers have deeply investi-gated the use of the proper QSSA, agreeing to highlight that only one type ofQSSA (the total QSSA) is able to faithfully replicate the qualitative behaviorof bistability occurrences, as well as the correct assessment of the equilibriumpoints, accordingly to the not approximated (full) model. Based on recent resultsproviding CME solutions that do not resort to Monte Carlo simulations, the pro-posed stochastic approach shows some counterintuitive facts arising when tryingto straightforwardly transfer bistability deterministic results into the stochasticrealm, and suggests how to handle such cases according to both theoretical andnumerical results

Effects due to the misalignment of build-up systems for force measurements in the Meganewton range

Calibration of force transducers in the Meganewton range is typically performed by comparison with reference build-up systems (BUS) under hydraulic presses for high loads. The centring of a BUS isa difficultoperation due to itsweight and dimension, andpossible misalignmentsand the resultingeffects are usually neglected.In this work the effect on force measurements due toa 3 mmmisalignment of a 3 MN BUS wasevaluated.Measurements were performed at INRiM and at LNE in hydraulic presses.Itis shown that the relative measurement errorsdue to misalignment were lowerthan the declared CMC uncertainty,thus the shiftof the BUSdid not influence the measurements