Vitis vinifera (Vitales: Vitaceae) as a Reproductive Host of Spissistilus festinus (Hemiptera: Membracidae).

Feeding by the three-cornered alfalfa hopper, Spissistilus festinus (Say) (Hemiptera: Membracidae) results in girdling of grapevine petioles and shoots. Its significance as an economic pest of grape has increased since it was shown to transmit Grapevine red blotch virus (GRBV) in a greenhouse study. However, the status of grapevines as a reproductive host for S. festinus remained undetermined. Adult S. festinus were caged onto three regions of the grapevines: apical shoot, green shoot, and dormant cane. Their ability to reproduce was determined by weekly destructive sampling for 7 wk. Successful oviposition and nymphal emergence were observed on apical and green shoots, but not on dormant canes. However, insect development beyond the second nymphal instar did not occur. Knowledge of S. festinus reproduction on grapevines will be an important consideration in designing management guidelines to minimize the spread of GRBV in vineyards

Vombat: An Open Source Tool for Creating Stratigraphic Logs from Virtual Outcrops

An open source tool, Vombat , is presented that is designed to operate on Virtual Outcrop Models of sedimentary rocks, with the specific aim of assisting the stratigraphic analysis and interpretation. Vombat makes it possible to estimate the average attitude of the bedding and to create one or more attitude-aligned stratigraphic reference frames. This allows Vombat to extract continuous stratigraphic logs of any property associated with the point clouds (e.g. the lidar intensity or RGB color). Stratigraphic logs produced by Vombat can be compared and correlated to typical outcrop logs and petrophysical logs obtained from boreholes (e.g. gamma ray logs) and can provide information about the lithological variations in a stratigraphic succession. Furthermore, Vombat stratigraphic reference frames can be used to associate a stratigraphic position (a depth in the stratigraphic column) to any observation made on the outcrop, allowing visualization in 3D (on the virtual outcrop model) and 1D (on a stratigraphic column) for any collected data. All the geological objects created in the virtual environment can then be saved. The tool has been developed to be user-friendly and is constituted by a dynamically loaded plugin for the open source software CloudCompare

Mechanical behavior of basalt fibers in a basalt-UP composite

AbstractWith the increasing interest in sustainable solutions in material design in the last decade, research on natural materials (animal, vegetal or mineral) has increased at a rapid pace. Of these materials, Basalt Fibers for composite construction provide an interesting set of mechanical properties, equal or above to those of Glass Fibers, with advantages in terms of cost effectiveness and production to vegetable based Natural Fibers. Basalt fibers offer some advantages versus current materials, it is fireproof, requires no material addition, has better mechanical properties than most types of E-Glass, and it is cheaper than Carbon Fiber. This paper studies the mechanical properties of a Basalt Fiber composite in an Unsaturated Polyester matrix produced by Resin Transfer Molding (RTM), with the composites subjected to tensile, compression, shear and flexural tests. The results aligned with the predicted values by using the mixing rule, albeit with a high coefficient of variation, which microscopic analysis confirmed to arise from production issues with RTM

The impact of realistic models of mass segregation on the event rate of extreme-mass ratio inspirals and cusp re-growth

One of the most interesting sources of gravitational waves (GWs) for LISA is the inspiral of compact objects on to a massive black hole (MBH), commonly referred to as an "extreme-mass ratio inspiral" (EMRI). The small object, typically a stellar black hole (bh), emits significant amounts of GW along each orbit in the detector bandwidth. The slowly, adiabatic inspiral of these sources will allow us to map space-time around MBHs in detail, as well as to test our current conception of gravitation in the strong regime. The event rate of this kind of source has been addressed many times in the literature and the numbers reported fluctuate by orders of magnitude. On the other hand, recent observations of the Galactic center revealed a dearth of giant stars inside the inner parsec relative to the numbers theoretically expected for a fully relaxed stellar cusp. The possibility of unrelaxed nuclei (or, equivalently, with no or only a very shallow cusp) adds substantial uncertainty to the estimates. Having this timely question in mind, we run a significant number of direct-summation $N-$body simulations with up to half a million particles to calibrate a much faster orbit-averaged Fokker-Planck code. We then investigate the regime of strong mass segregation (SMS) for models with two different stellar mass components. We show that, under quite generic initial conditions, the time required for the growth of a relaxed, mass segregated stellar cusp is shorter than a Hubble time for MBHs with $M_\bullet \lesssim 5 \times 10^6 M_\odot$ (i.e. nuclei in the range of LISA). SMS has a significant impact boosting the EMRI rates by a factor of $\sim 10$ for our fiducial models of Milky Way type galactic nuclei.Comment: Accepted by CQG, minor changes, a bit expande

Improved production of acetate and propionate by Propionibacterium freudenreichii

Propionibacterium freudenreichii is a commercially important bacterium that is well-known for its role as ripening starter in the cheese industry and its probiotic potential. These bacteria may beneficially modulate the intestinal ecosystem and can exert anti-neoplastic effects via the production of short chain fatty acids (SCFAs), acetate and propionate. Several studies have demonstrated that the SCFA production by P. freudenreichii is responsible for its probiotic abilities. The aim of this work was to optimize the acetate and propionate production by P. freudenreichii towards its future use as a nutraceutical agent. In order to optimize the production of the abovementioned SCFAs in a minimal synthetic media the different composition of the several components were evaluated. Characterization of the acetate and propionate production in a medium mimicking the content of the human colon (MCHC) and a medium used by colorectal carcinoma cell lines (DMEM) was performed. The basal medium (BM) was found to be the most promising regarding the production of the SCFAs, showing 0.530 ± 0.011 g L-1 of biomass; high acetate and propionate yields (0.216 ± 0.001 g g-1 and 0.572 ± 0.002 g g-1, respectively), as well as high productivities (0.031 ± 0.000 g L-1 h-1 and 0.010 ± 0.000 g L-1 h-1, respectively). In the MCHC and DMEM media, it was possible to observe microbial growth (0.234 ± 0.006 g L-1 and 1.54 ± 0.00 g L-1, respectively); however the amounts of acetate and propionate were lower than the ones produced in BM medium. The results suggest that acetate and propionate production depends not only on the substrate type, but also on the medium constituents, being the simplest medium the one that show higher productivities as P. freudenreichii show low SCFA production when grown in MCHC and DMEM media. Future work will be conducted in order the increase bacteria growth and SCFA production in those media as this represents an essential feature for its use as a nutraceutical

Intermittent chaos driven by nonlinear Alfvén waves

International audienceWe investigate the relevance of chaotic saddles and unstable periodic orbits at the onset of intermittent chaos in the phase dynamics of nonlinear Alfvén waves by using the Kuramoto-Sivashinsky (KS) equation as a model for phase dynamics. We focus on the role of nonattracting chaotic solutions of the KS equation, known as chaotic saddles, in the transition from weak chaos to strong chaos via an interior crisis and show how two of these unstable chaotic saddles can interact to produce the plasma intermittency observed in the strongly chaotic regimes. The dynamical systems approach discussed in this work can lead to a better understanding of the mechanisms responsible for the phenomena of intermittency in space plasmas

A hybrid MLS technique for room impulse response estimation

The measurement of room impulse response (RIR) when there are high background noise levels frequently means one must deal with very low signal-to-noise ratios (SNR). if such is the case, the measurement might yield unreliable results, even when synchronous averaging techniques are used. Furthermore, if there are non-linearities in the apparatus or system time variances, the final SNR can be severely degraded. The test signals used in RIR measurement are often disturbed by non-stationary ambient noise components. A novel approach based on the energy analysis of ambient noise - both in the time and in frequency - was considered. A modified maximum length sequence (MLS) measurement technique. referred to herein as the hybrid MLS technique, was developed for use in room acoustics. The technique consists of reducing the noise energy of the captured sequences before applying the averaging technique in order to improve the overall SNRs and frequency response accuracy. Experiments were conducted under real conditions with different types of underlying ambient noises. Results are shown and discussed. Advantages and disadvantages of the hybrid MLS technique over standard MLS technique are evaluated and discussed. Our findings show that the new technique leads to a significant increase in the overall SNR. (C) 2008 Elsevier Ltd. All rights reserved

Innovation reliability and variability strategies: the importance of absorptive capacity on systemic outcomes

The role of absorptive capacity (AC) has been widely recognized in the innovation literature. This study examines the predictive role of AC for business performance, and evaluates the mediation of market orientation (responsive-proactive) and innovation competences orientation (exploitation-exploration) in that relationship. It addresses the gap in the literature on the relative importance of innovation competence orientations versus market orientations. The findings show that innovation competence orientations are more important to business performance than market orientations and that innovation competences are better enhanced by AC than by market orientations. AC is not only confirmed as an antecedent of ambidextrous market and innovation competence orientation, but it also helps directly and indirectly to explain business performance. Responsive market orientation and innovation competence orientation mediate the positive relationship between AC and business performance. The intensity and significance of the indirect effects reveal the specific knowledge-transformative roles of market and innovation competences orientations. Firms seem to mitigate uncertainty by adjusting their preferences toward less risky innovation strategies. Managerial implications highlight the relevance of innovation competences orientation versus market orientation. Furthermore, firms seem to use proactive market orientation ineffectively, a finding that signals a structural marketing handicap.info:eu-repo/semantics/acceptedVersio

Fostering knowledge creation to improve performance: the mediation role of manufacturing flexibility

Purpose This study examines the mediating role of manufacturing flexibility in the relationship between knowledge creation, technological turbulence, and performance. In an increasingly competitive and changing environment, firms need to boost their technological and management know-how to adequately develop manufacturing flexibility. Design/methodology/approach The study analyzes survey data collected from 370 manufacturing firms. Validity and reliability analyses were conducted using SPSS and Amos. The research hypotheses were tested using covariance-based structural equation modeling. Findings The main findings show that knowledge creation positively and significantly affects business and operational performances directly, and indirectly, through manufacturing flexibility. Moreover, technological turbulence has a positive and significant effect on it. This finding contributes to understanding why some firms get better outcomes from manufacturing flexibility than others, a disputed issue in the literature. Practical implications This study highlights the need for manufacturing firms to foster cultures of knowledge creation, to better educate and train employees, and to develop other instruments of knowledge creation. Originality/value This study makes several contributions to manufacturing flexibility literature: (i) establishing a link between technological turbulence and knowledge creation develop manufacturing flexibility; (ii) add empirical evidence on the relation between manufacturing flexibility and performance; (iii) contributes to consolidating the mediation role of manufacturing flexibility in the relations between knowledge creation and business performance, as studies focusing on such a role are scarce in the literature.info:eu-repo/semantics/acceptedVersio

Effects of absorptive capacity and innovation spillover on manufacturing flexibility

Shifting demand and ever-shorter production cycles pressure manufacturing flexibility. Although the literature has established the positive effect of the firm’s absorptive capacity on manufacturing flexibility, the separate role of the innovation competencies of exploitation and exploration in such a relationship is still under-investigated. In this study, we examine how these competencies affect manufacturing flexibility. We use survey data from 370 manufacturing firms and analyze them using covariance-based structural equation modeling (CB-SEM). The results indicate that absorptive capacity has a strong, positive, and direct effect on exploitative and exploratory innovation competencies, proactive and responsive market orientations, and manufacturing flexibility. Our findings also demonstrate that the exploratory innovation competencies mediate the relation between responsive market orientation and manufacturing flexibility. Essentially, these exploitative innovation competencies produce a direct positive effect on manufacturing flexibility while simultaneously being a vehicle for absorptive capacity’s indirect effects on it. An exploration innovation strategy does not significantly affect manufacturing flexibility. This study contributes by combining key strategic features of firms with manufacturing flexibility, while providing new empirical evidence of the mediation of the exploratory innovation competencies in the relation between responsive market orientation and manufacturing flexibility.info:eu-repo/semantics/acceptedVersio