Groups of prime power order with many conjugacy classes

[No abstract available

Exploratory study of sugar and C(6) compounds in single berries of grapevine ( Vitis vinifera L.) cv. Cabernet Sauvignon throughout ripening

Background and Aims: This study explored changes in the profile of selected aroma compounds in individual berries during development to establish whether a correlation exists between aroma compounds and sugar. Previous studies have assessed changes in the aroma compounds of ripening grapes using multiple berries randomly pooled together or sorted according to their diameter, density or colour. These data, while of value from a winemaking perspective, may prevent a fine interpretation of the compositional changes within individual berries characterised by asynchronous development. Methods and Results: Individual berries of Vitis vinifera cv. Cabernet Sauvignon at different stages of development were sampled from veraison to harvest. Sugar concentration and mass of individual berries were measured, and C6 compounds analysed. The content of C6 compounds per berry was strongly correlated to the stage of development, while changes between stages were compound specific. Berries of similar TSS shared comparable composition of C6 compounds, with little influence of the sampling date. Conclusions: Investigation of the composition of individual berries during ripening showed a strong dependency between the stage of development and the composition of sugar and C6 compounds. Significance of the Study: Compositional changes of metabolites occurring in individual grape berries throughout ripening were identified. This study provides a starting point for a detailed study of the sugar/flavour nexus that may lead to an improved understanding of how to produce grapes with less sugar and more aroma, to overcome challenges associated with climate change.P. Previtali, N. Dokoozlian, D.L. Capone, K.L. Wilkinson, C.M. For

Crop load and plant water status influence the ripening rate and aroma development in berries of grapevine (Vitis vinifera L.) cv. Cabernet Sauvignon

Published: June 30, 2021Wine made from grapes subjected to accelerated ripening, an increasingly frequent phenomenon occurring in many wine regions due to peaks of heat and water stress, displays higher alcohol levels and lacks balance with color and flavor compounds. Herein, the rate of sugar accumulation of grapes was manipulated by varying the crop load and irrigation regime and the development of secondary metabolites was monitored by gas chromatography-mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC). A 3-week delay in ripening correlated to an increase in the concentration of some monoterpenes and norisoprenoids and a greater decrease of green aroma compounds. Delayed ripening had a positive impact on the phenolic composition of grapes, displaying higher contents of total anthocyanins, total phenolics, quercetin glycosides, and polymeric pigments. A map of the chemical composition of grapes close to harvest allowed discrimination of compounds mainly responsive to delayed ripening from those driven by crop load or irrigation.Pietro Previtali, Nick K. Dokoozlian, Bruce S. Pan, Kerry L. Wilkinson, and Christopher M. For

The effect of ripening rates on the composition of Cabernet Sauvignon and Riesling wines: Further insights into the sugar/flavor nexus

Available online 14 October 2021Grape ripening accelerates under warmer and drier conditions, resulting in the accumulation of sugars (‘technological’ maturity) being decoupled from phenolic and aromatic composition. This study investigated the effect of different rates of ripening on the composition of Cabernet Sauvignon and Riesling wines. Manipulating crop load and irrigation led to distinct rates of berry ripening. In the resulting wines, reduced crop load affected the aroma composition, altering the profile and abundance of grape-derived compounds and fermentative esters. Phenolic composition was impacted by the irrigation regime, with color and tannin increased by late season irrigation. In Cabernet Sauvignon, the combination of treatments led to the largest ripening delay (3 weeks), resulting in less green and more fruity compounds, and improved phenolic composition. By mapping grape and wine metabolites and exploring their relationship, the outcomes of this study demonstrate the importance of ripening rates in determining wine quality.Pietro Previtali, Nick K. Dokoozlian, Bruce S. Pan, Kerry L. Wilkinson, Christopher M. For

A systematic review and meta-analysis of vineyard techniques used to delay ripening

Several vineyard techniques have been proposed to delay grape maturity in light of the advanced maturation driven by increasingly frequent water and heat stress events that are detrimental to grape quality. These studies differ in terms of their experimental conditions, and in the present work we have attempted to summarize previous observations in a quantitative, data-driven systematic review. A meta-analysis of quantitative data gathered across 43 relevant studies revealed the overall significance of the proposed treatments and evaluated the impact of different experimental conditions on the outcome of antitranspirants, delayed pruning and late source limitation. Antitranspirants were most effective when applied twice and closer to veraison, while di-1-p-menthene increased the ripening delay by about 1 °Brix compared to kaolin. Larger ripening delays were achieved with delayed pruning of low-yielding vines or by pruning at later stages of apical bud development. Late defoliation or shoot trimming delayed ripening in high-yielding vines and represent suitable solutions for late-harvested varieties, but became ineffective where the treatment decreased yield. This quantitative meta-analysis of 242 primary observations uncovers factors affecting the efficacy of vineyard practices to delay ripening, which should be carefully considered by grape growers attempting to achieve this outcome.Pietro Previtali, Filippo Giorgini, Randall S. Mullen, Nick K. Dookozlian, Kerry L.Wilkinson and Christopher M. For

Study of a low-power, fast-neutron-based ADS

Within European Partitioning & Transmutation research programs, infrastructures specifically dedicated to the study of fundamental reactor physics and engineering parameters of future fast-neutron-based reactors are very important, being some of these features not available in present zero-power prototypes. This presentation will illustrate the conceptual design of an ADS with high safety standards, but ample flexibility for measurements. The design assumes as base option the 70 MeV, 0.75 mA proton cyclotron facility planned to be constructed at the INFN National Laboratory in Legnaro, Italy and a Beryllium target, with Helium gas as core coolant. Safety is guaranteed by limiting the thermal power to 200 kW, with a neutron multiplication coefficient around 0.95, loading the core with fuel containing Uranium enriched at 20% and a solid-lead diffuser. The small decay heat can be passively removed by thermal radiation from the vessel. Such a system could be used to study, among others, some specific aspects of neutron diffusion in lead, beam-core coupling, target cooling and could serve as a training facility

Study of an intrinsically safe infrastructure for training and research on nuclear technologies

Within European Partitioning & Transmutation research programs, infrastructures specifically dedicated to the study of fundamental reactor physics and engineering parameters of future fast-neutron-based reactors are very important, being some of these features not available in present zero-power prototypes. This presentation will illustrate the conceptual design of an ADS with high safety standards, but ample flexibility for measurements. The design assumes as base option a 70 MeV, 0.75 mA proton cyclotron, as the one which will be installed at the INFN National Laboratory in Legnaro, Italy and a Beryllium target, with Helium gas as core coolant. Safety is guaranteed by limiting the thermal power to 200 kW, with a neutron multiplication coefficient around 0.94, loading the core with fuel containing Uranium enriched at 20% inserted in a solid-lead diffuser. The small decay heat can be passively removed by thermal radiation from the vessel. Such a system could be used to study, among others, some specific aspects of neutron diffusion in lead, beam-core coupling, target cooling and could serve as a training facility