704 research outputs found

    Stability of Ampelometric Characteristics of Vitis vinifera L. cv. 'Syrah' and 'Sauvignon blanc' Leaves: Impact of Within-vineyard Variability and Pruning Method/Bud Load

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    Historically, grapevine (Vitis vinifera L.) leaf characterisation has been a driving force in the identification of cultivars. In this study, ampelometric (foliometric) analysis was done on leaf samples collected from hand-pruned, mechanically pruned and minimally pruned ‘Sauvignon blanc’ and ‘Syrah’ vines to estimate the impact of within-vineyard variability and a change in bud load on the stability of leaf properties. The results showed that within-vineyard variability of ampelometric characteristics was high within a cultivar, irrespective of bud load. In terms of the O.I.V. coding system, zero to four class differences were observed between minimum and maximum values of each characteristic. The value of variability of each characteristic was different between the three levels of bud load and the two cultivars. With respect to bud load, the number of shoots per vine had a significant effect on the characteristics of the leaf laminae. Single leaf area and lengths of veins changed significantly for both cultivars, irrespective of treatment, while angle between veins proved to be a stable characteristic. A large number of biometric data can be recorded on a single leaf; the data measured on several leaves, however, are not necessarily unique for a specific cultivar. The leaf characteristics analysed in this study can be divided into two groups according to the response to a change in bud load, i.e. stable (angles between the veins, depths of sinuses) and variable (length of the veins, length of the petiole, single leaf area). The variable characteristics are not recommended to be used in cultivar identification, unless the pruning method/bud load is known

    Excitation spectra for Andreev billiards of box and disk geometries

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    We study Andreev billiards of box and disk geometries by matching the wave functions at the interface of the normal and the superconducting region using the exact solutions of the Bogoliubov-de Gennes equation. The mismatch in the Fermi wave numbers and the effective masses of the normal system and the superconductor, as well as the tunnel barrier at the interface are taken into account. A Weyl formula (for the smooth part of the counting function of the energy levels) is derived. The exact quantum mechanical calculations show equally spaced singularities in the density of states. Based on the Bohr-Sommerfeld quantization rule a semiclassical theory is proposed to understand these singularities. For disk geometries two kinds of states can be distinguished: states either contribute through whispering gallery modes or are Andreev states strongly coupled to the superconductor. Controlled by two relevant material, parameters, three kinds of energy spectra exist in disk geometry. The first is dominated by Andreev reflections, the second, by normal reflections in an annular disk geometry. In the third case the coherence length is much larger than the radius of the superconducting region, and the spectrum is identical to that of a full disk geometry

    Structure - Activity Relationships in the Antiinflammatory Steroids: A Pattern Recognition Approach

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    A pattern recognition technique has been used to determine structure-activity relationships for antiinflammatory steroids. Expe.:. rimental results using the human vasoconstrictor test of McKenzie and Stoughton and the rat granuloma cotton pellet method of Meier were correlated with the various substructural descriptors. Steroids were classified into two categories according to potency and a pattern recognition method was applied to determine their relative ranking. The resulting structure-activity relationships obtained and the relative contributions of the various structural variables for both bioassays are discussed. A synergistic effect was predicted to be in operation between certain pairs of substituents

    Measuring the Food Environment: A Systematic Technique for Characterizing Food Stores Using Display Counts

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    Marketing research has documented the influence of in-store characteristics—such as the number and placement of display stands—on consumer purchases of a product. However, little information exists on this topic for key foods of interest to those studying the influence of environmental changes on dietary behavior. This study demonstrates a method for characterizing the food environment by measuring the number of separate displays of fruits, vegetables, and energy-dense snack foods (including chips, candies, and sodas) and their proximity to cash registers in different store types. Observations in New Orleans stores (N = 172) in 2007 and 2008 revealed significantly more displays of energy-dense snacks than of fruits and vegetables within all store types, especially supermarkets. Moreover, supermarkets had an average of 20 displays of energy-dense snacks within 1 meter of their cash registers, yet none of them had even a single display of fruits or vegetables near their cash registers. Measures of the number of separate display stands of key foods and their proximity to a cash register can be used by researchers to better characterize food stores and by policymakers to address improvements to the food environment

    Structure - Activity Relationships in the Antiinflammatory Steroids: A Pattern Recognition Approach

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    A pattern recognition technique has been used to determine structure-activity relationships for antiinflammatory steroids. Expe.:. rimental results using the human vasoconstrictor test of McKenzie and Stoughton and the rat granuloma cotton pellet method of Meier were correlated with the various substructural descriptors. Steroids were classified into two categories according to potency and a pattern recognition method was applied to determine their relative ranking. The resulting structure-activity relationships obtained and the relative contributions of the various structural variables for both bioassays are discussed. A synergistic effect was predicted to be in operation between certain pairs of substituents

    A Study of the Interactions Between the Double Bonds in Unsaturated Ketones

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    The interactions between C=C and C=O double bonds in several unsaturated ketones have been studied by comparing MIND0/2 caloulations wiith ionisation potentials determined by photoelectron spectroscopy (PES). With one exception (norbornadienone) the direct through-space interactions in conjugated .ketones appear to be negligible, the double bonds couple hyperoonjugatively via the intervening a bonds. This kind of approach should prove useful for studying other long range interactions

    Outline analysis of the grapevine (Vitis vinifera L.) berry shape by elliptic Fourier descriptors

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    Grapevine berry morphology is one of the most important features in table grape production. In this study, berry samples of 46 grapevine accessions were investigated for 3 consecutive years with elliptic Fourier descriptors (EFD) to evaluate shape diversity. Ten reference shapes obtained from the OIV descriptor list were involved and principal component (PC) scores summarizing the EFD's were statistically evaluated with Two way ANOVA and discriminant analysis. The cummulative contribution of the five principal components was 96.83 %. Two way ANOVA revealed that berry shape had high variability within the accessions and years. Based on the linear discriminant analysis, reference shapes were compared to those of the accessions and graphic reconstruction was carried out. OIV references were considered as unknown samples and grouped into the accession classes. Overall correct classification of the accessions into their group was 13.88 %. Our results showed that EFD together with reference shapes are a powerful method to discribe berry shape and possibly give the future basis of uvometric evaluation of grapevine cultivars

    Graled (Grapevine leaf digitalization) Software for the Detection and Graphic Reconstruction of Ampelometric Differences Between Vitis Leaves

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    Raster graphic ampelometric software was not exclusively developed for the estimation of leaf area, but also for the characterization of grapevine (Viti vinifera L.) leaves. The software was written in C-Hprogramming language, using the C-1-1- Builder 2007 for Windows 95-XP and Linux operation systems. It handles desktop-scanned images. On the image analysed with the GRA.LE.D., the user has to determine 11 points. These points are then connected and the distances between them calculated. The GRA.LE.D. software supports standard ampelometric measurements such as leaf area, angles between the veins and lengths of the veins. These measurements are recorded by the software and exported into plain ASCII text files for single or multiple samples. Twenty-two biometric data points of each leaf are identified by the GRA.LE.D. It presents the opportunity to statistically analyse experimental data, allows comparison of cultivars and enables graphic reconstruction of leaves using the Microsoft Excel Chart Wizard. The GRA. LE.D. was thoroughly calibrated and compared to other widely used instruments and methods such as photo-gravimetry, LiCor L0100, WinDIAS2.0 and ImageTool. By comparison, the GRA.LE.D. presented the most accurate measurements of leaf area, but the LiCor L0100 and the WinDIAS2.0 were faster, while the photo-gravimetric method proved to be the most time-consuming. The WinDIAS2.0 instrument was the least reliable. The GRA.LE.D. is uncomplicated, user-friendly, accurate, consistent, reliable and has wide practical application

    O fra Bernardinu Splićaninu, priređivaču prvog izdanja hrvatskog lekcionara, ponovo!

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    The use of miniaturised isotachophoresis to allow the simultaneous determination of two inorganic selenium species has been investigated using a poly(methyl methacrylate) chip with a 44-mm-long, 200-ÎŒm-wide, 300-ÎŒm-deep separation channel. The miniaturised device included an integrated on-column, dual-electrode conductivity detector and was used in conjunction with a hydrodynamic fluid transport system. A simple electrolyte system has been developed which allowed the separation of selenium(IV) and selenium(VI) species to be made in under 210 s. The limits of detection were calculated to be 0.52 mg L−1 for selenium(IV) and 0.65 mg L−1 for selenium(VI). The method allowed the separation of the selenium species from a range of common anions including fluoride, nitrate, nitrite, phosphate, sulfate and sulfite

    Assembly in G1 phase and long-term stability are unique intrinsic features of CENP-A nucleosomes

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    Centromeres are the site of kinetochore formation during mitosis. Centromere protein A (CENP-A), the centromere-specific histone H3 variant, is essential for the epigenetic maintenance of centromere position. Previously we showed that newly synthesized CENP-A is targeted to centromeres exclusively during early G1 phase and is subsequently maintained across mitotic divisions. Using SNAP-based fluorescent pulse labeling, we now demonstrate that cell cycle-restricted chromatin assembly at centromeres is unique to CENP-A nucleosomes and does not involve assembly of other H3 variants. Strikingly, stable retention is restricted to the CENP-A/H4 core of the nucleosome, which we find to outlast general chromatin across several cell divisions. We further show that cell cycle timing of CENP-A assembly is independent of centromeric DNA sequences and instead is mediated by the CENP-A targeting domain. Unexpectedly, this domain also induces stable transmission of centromeric nucleosomes, independent of the CENP-A deposition factor HJURP. This demonstrates that intrinsic properties of the CENP-A protein direct its cell cycle-restricted assembly and induces quantitative mitotic transmission of the CENP-A/H4 nucleosome core, ensuring long-term stability and epigenetic maintenance of centromere position.FCT fellpwships: (SFRH/BD/74284/2010, SFRH/BPD/69115/2010), National Institutes of Health grant: (GM082989), Burroughs Wellcome Fund (Career Award in the Biomedical Sciences), Rita Allen Foundation Scholar Award, Instituto Gulbenkian de CiĂȘncia, European Commission FP7 Program, EMBO
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