Orbits in symmetric spaces, II

Suppose $E$ is fully symmetric Banach function space on $(0,1)$ or $(0,\infty)$ or a fully symmetric Banach sequence space. We give necessary and sufficient conditions on $f\in E$ so that its orbit $\Omega(f)$ is the closed convex hull of its extreme points. We also give an application to symmetrically normed ideals of compact operators on a Hilbert space

Logistics and Agri\u2010Food: Digitization to Increase Competitive Advantage and Sustainability. Literature Review and the Case of Italy

This paper examines the current challenges faced by logistics with a focus on the agri\u2010food sector. After outlining the context, a review of the literature on the relationship between logistics and strategic management in gaining and increasing competitiveness in the agri\u2010food sector is con-ducted. In particular, the flow of the paper is as follows: after examining the aforementioned managerial problem and its broader repercussions, the paper proceeds to address two main research questions. First, how and by which tools can digitization contribute to improving supply chain management and sustainability in logistics? Second, what are the main managerial and strategic implications and consequences of this for the agri\u2010food sector in terms of efficiency, effectiveness, cost reduction, and supply chain optimization? Finally, the paper presents Italy as a case study, chosen both for its peculiar internal differences in logistical infrastructures and entrepreneurial management between Northern and Southern regions (which could be at least partially overcome with the use of new technologies and frameworks) and for the importance of the agri\u2010food sector for the domestic economy (accounting about 25% of the country\u2019s GDP), on which digitization should have positive effects in terms of value creation and sustainability

The effect of drought stress on the green spruce aphid

The green spruce aphid, Elatobium abietinum (Walker) (Hemiptera: Aphididae), is the most important defoliating pest of Sitka spruce, Picea sitchensis (Bong.) Carr., in the U.K. Currently, populations of this aphid are limited by freezing periods in the winter, while interactions between climate and other factors regulate population dynamics. Climate change in the U.K. is predicted to result in: (1) warmer winters, improving overwinter survival by aphid populations, and (2) an increase in hot and dry summers, likely to place Sitka spruce under drought stress. These could promote aphid densities and increased damage to the trees, resulting in losses to plant growth and productivity. Few studies have been conducted on the effect of drought stress on arboreal herbivores. This project sought to explore the effects of different intensities of spring-summer drought stress on E. abietinum on Sitka spruce. Populations and their effects on their host plant, in terms of needle retention and impact on tree growth, were observed in a semi-field nursery setting. The performance of individual aphids was also observed under controlled conditions at intervals following bud-burst in spring, and again in autumn. Finally, a study was conducted on the consumption rates of specialist and generalist Coccinellid predators feeding on aphids reared under differing drought intensities. Elatobium abietinum exhibited an overall positive response to moderate intermittent drought stress, while severe stress was typically detrimental. When considered with aphid size, Coccinellid predator consumption rates reflected these findings. Changes to damage levels on Sitka spruce can therefore be expected under drought stress; increases are likely under moderate intermittent stress, though the nature of changes under severe stress levels remain unclear. The results revealed complex interactions between drought stress, E. abietinum and Sitka spruce. Given the potential impact of the aphid, it is important to understand the possible responses under climate change.Open Acces