1,721,586 research outputs found
Preface
No full textThe Russian-Ukrainian war is the most serious geopolitical conflict since the Second World War and will have certainly more significant global consequences than the previous financial or health crises suffered in the last twenty years.
In this particular critical moment, it is necessary to carefully analyze and evaluate the foreseeable repercussions on food and energy supplies and the potential impact on the international scene. At the same time, it appears indispensable and urgent to respond flexibly to current dynamics and make strategic choices consistent with long-term interests.
The direct and indirect criticalities generated by the difficult situation that has developed in recent times, have already determined negative impacts on the current management of agricultural production and food products, with high-risk consequences for the stability of numerous agri-food chains.
These critical issues immediately have a different impact depending on the sector such as, for example:
- for cereal crops, protein and oil crops there is the sudden unavailability of raw materials due to the closure of important markets, the consequent sharp rise in prices also due to limitations in logistics and procurement;
- in the fruit and vegetable sector, there may be an oversupply on domestic markets and a drop in the remuneration of producers;
- in the nursery and horticultural sector in hot greenhouses, the interruption of production processes may occur due to the increase in fuel prices for heating;
- in breeding, the unavailability of basic raw materials for the production of feed and therefore for nutrition, also exacerbated by an unsustainable increase in energy costs, could lead to the impossibility of completing the production cycles, forcing farmers to resort to the slaughter of heads in full production.
In the medium to long term, these criticalities can aggravate some structural problems of agricultural systems such as, for example:
- the growing dependence on foreign countries for genetic materials (varieties and hybrids) used for national crops, such as corn and wheat;
- the continuing difficult situation for many companies linked to the scarce availability of necessary manpower and production costs that often exceed the remuneration of the products;
- the increase in fuel costs, with an immediate impact on fruit processing and conditioning plants and on transport to markets.
In this difficult and cyclical phase of instability, the eleventh edition of the “Farm Machinery and Process Management in Sustainable Agriculture” International Symposium was an opportunity to present and discuss some proposals based on objective criteria to be implemented in the short and medium term to address the main problems and possible solutions for agriculture and for the entire agri-food system.
The FMPMSA International Symposium, in large part, in responding to the ambitious goal of proposing scientific and technological solutions as well as structural measures useful for increasing the resilience of agri-food systems
Structural modifications for squeal noise reduction
No full textBrake squeal is an example of noise caused by vibrations induced by friction forces that can lead to a dynamic instability. The onset of squeal is due to the lock-in phenomenon, i.e. the instability occurring when two modes of the system coalesce and one becomes unstable. The sensitivity of the onset of instabilities with respect to the system parameters is due to the high modal density and to the large uncertainties on the dynamics of the single brake. This makes impossible the design of a 'squeal-free' brake apparatus. This paper suggests an innovative approach to avoid the growth of squeal vibrations, by exploiting the introduction of lumped structural modifications in the disc. The modification rotates with the disc while the disc modes are fixed in space. Depending on the relative position between the concentrated modification and the nodes of the disc modes, the natural frequencies of the disc shift back and forward. This expedient allows to change continuously the lock-in conditions between the system modes that are involved in squeal. The vibrations due to the lock-in between the pair of modes have not enough time to increase because of the repetitive look-out and they can be reduced until they completely disappear
Chemical Selectivity through Control of Excited–State Dynamics
No full text(Graph Presented) Trust is good, control is better: In thermal processes in which the interconversion of reactant conformers R1/2 is faster than the reaction itself, selectivity can be tailored by modulating the energy barriers of competing reaction paths. Ultrafast photoexcitation promotes separate conformers to different regions of the potential energy surface, where the wave packet may reach different conical intersections CI1/2, giving rise to product selectivity (P1/2). © 2008 Wiley-VCH Verlag GmbH & Co. KGaA
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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