Plant Diversity in an Intensively Cultivated Vineyard Agroecosystem (Langhe, North-West Italy)

In areas of intensive agriculture, wild plant species are confined to field margins, thus they play a role inprotecting biodiversity. The aim of the present study was to assess plant diversity in an area of intensiveviticulture and to evaluate, for the first time, the impact of field margins on vineyard flora biodiversity. Thestudy was conducted in North-West Italy, were five categories of floristic lists in vineyard-margin pairs weresampled and compared. Five margins were identified: grass-covered (A) and bare (B) headlands, small (C)and wide (D) woodlands, and shrub and herbaceous (E) areas. Two hundred and fifty-two taxa were found,although only 19 were widespread. Differences among categories emerged, highlighting the high floristiccomplexity of the sites surrounded by wide wooded areas (D). The findings suggest an influence of marginsize, in addition to margin type, on the floristic richness of the vineyard. Moreover, an inverse relationshipbetween species richness and both the presence of Poaceae and the degree of soil grass coverage emerged.Enhancing biodiversity, at landscape and field level, by the appropriate management of cover crops andecological infrastructures, within and around vineyards, could be a strategy in sustainable viticulture.The increase in plant species richness is not an end in itself, but it might help to promote biodiversity atdifferent trophic levels

On the monotone stability approach to BSDEs with jumps: Extensions, concrete criteria and examples

We show a concise extension of the monotone stability approach to backward stochastic differential equations (BSDEs) that are jointly driven by a Brownian motion and a random measure for jumps, which could be of infinite activity with a non-deterministic and time inhomogeneous compensator. The BSDE generator function can be non convex and needs not to satisfy global Lipschitz conditions in the jump integrand. We contribute concrete criteria, that are easy to verify, for results on existence and uniqueness of bounded solutions to BSDEs with jumps, and on comparison and a-priori $L^{\infty}$-bounds. Several examples and counter examples are discussed to shed light on the scope and applicability of different assumptions, and we provide an overview of major applications in finance and optimal control.Comment: 28 pages. Added DOI https://link.springer.com/chapter/10.1007%2F978-3-030-22285-7_1 for final publication, corrected typo (missing gamma) in example 4.1

A common mechanism for efficient N 2 O reduction in diverse isolates of nodule‐forming bradyrhizobia

Bradyrhizobia are abundant soil bacteria, which can form nitrogen‐fixing symbioses with leguminous plants, including important crops such as soybean, cowpea and peanut. Many bradyrhizobia can denitrify, but studies have hitherto focused on a few model organisms. We screened 39 diverse Bradyrhizobium strains, isolated from legume nodules. Half of them were unable to reduce N2O, making them sources of this greenhouse gas. Most others could denitrify NO3‐ to N2. Time‐resolved gas kinetics and transcription analyses during transition to anaerobic respiration revealed a common regulation of nirK, norCB and nosZ (encoding NO2‐, NO and N2O reductases), and differing regulation of napAB (encoding periplasmic NO3‐ reductase). A prominent feature in all N2‐producing strains was a virtually complete hampering of NO3‐ reduction in presence of N2O. In‐depth analyses suggest that this was due to a competition between electron transport pathways, strongly favouring N2O over NO3‐ reduction. In a natural context, bacteria with this feature would preferentially reduce available N2O, produced by themselves or other soil bacteria, making them powerful sinks for this greenhouse gas. One way to augment such populations in agricultural soils is to develop inoculants for legume crops with dual capabilities of efficient N2‐fixation and efficient N2O reduction

Quadratic BSDEs driven by a continuous martingale and application to utility maximization problem

In this paper, we study a class of quadratic Backward Stochastic Differential Equations (BSDEs) which arises naturally when studying the problem of utility maximization with portfolio constraints. We first establish existence and uniqueness results for such BSDEs and then, we give an application to the utility maximization problem. Three cases of utility functions will be discussed: the exponential, power and logarithmic ones

The Opportunity Process for Optimal Consumption and Investment with Power Utility

We study the utility maximization problem for power utility random fields in a semimartingale financial market, with and without intermediate consumption. The notion of an opportunity process is introduced as a reduced form of the value process of the resulting stochastic control problem. We show how the opportunity process describes the key objects: optimal strategy, value function, and dual problem. The results are applied to obtain monotonicity properties of the optimal consumption.Comment: 24 pages, forthcoming in 'Mathematics and Financial Economics