1,720,981 research outputs found
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
Novel nanoscaled materials from lignocellulosic sources: Potential applications in the agricultural sector
No full textThe agricultural sector is facing pivotal global challenges such as climate change, urbanization, sustainable use of resources, and environmental issues. These situations are further exacerbated by the growing food demand that will be needed to sustain an estimated population growth from the current level of about 6 billion to 9 billion by 2050. Plant-based agricultural production is the base of the broad agriculture systems providing food, feed, fiber, and fuels. While the demand for crop yield will rapidly increase in the future, the agriculture and natural resources are limited. In this scenario, traditional strategies for plant protection often result insufficient, and the application of chemical-based pesticides has negative effects on the environment, animals, and humans. Nanotechnology has the potential to conceive products based on environmentally friendly natural polymers which, in addition of being biodegradable, can also be obtained from natural sources and/or biowastes. Specifically, lignocellulosic materials are the most promising feedstock as natural and renewable resources essential to the functioning of modern industrial societies, and the huge amounts of lignocellulosic biomass can potentially be converted into high-value products for different final applications. Current research trends and recent advances about the extraction methodologies and properties of nanostructured materials and systems from lignocellulosic biomass and their potential applications in sustainable plant protection for agriculture management will be presented in this chapter, while potential future applications will be analyzed and discussed
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
Susceptibility of local grape cultivars to Plasmopara viticola and response to copper compounds with low cupric salt concentration in Latium (Central Italy)
No full textThe EU restrictions to the use of copper salts in organic viticulture has suggested to study the possibilities to control the fungal pathogen Plasmopara viticola with rameic compounds characterized by low cupric salts concentration and to evaluate varietal response. The trial was carried out in Latium region (Central Italy) on two local cultivars: ‘Rossetto’ or ‘Trebbiano giallo’, ‘Romanesco’ and on ‘Trebbiano toscano’ or ‘Procanico’. Three copper compounds with low cupric concentration (sulphate peptidate 5%, sulphate penthahydrate 5.5%, hydroxide peptidate 7%) were compared with copper sulphate 13%. Untreated plants of ‘Romanesco’ and ‘Rossetto’ revealed a lower susceptibility to Plasmopara viticola than ‘Procanico’. ‘Romanesco’ and ‘Procanico’ showed a better response than ‘Rossetto’ to the applied sprays. Low copper compounds efficiently protected leaves and clusters in all cultivars and prevented early leaf fall and senescence with respect to untreated plants, without phytotoxic effects. Yield and grape quality were not negatively affected by the compared treatments
Natural antimicrobials in spray-dried microparticles based on cellulose derivatives as potential eco-compatible agrochemicals
No full textIt has been demonstrated that some aromatic substances synthesized by plants serve as plant defense mechanisms. However, natural extracts are difficult to use due to their poor physicochemical characteristics and low concentration. Biocompatible microparticles for the delivery of the model antimicrobial compound Gallic acid (GA) were prepared by spray drying technique using hydroxylpropyl-methylcellulose-phtalate (HPMCP) and ethyl cellulose. The selection of appropriate experimental parameters allowed the obtaining of the following instrumental settings: (a) feed rate of the polymer solution 0.6 ml/min, (b) air flow rate of the nebulization device 600 l/h, © flow of drying air 28 m3/h and (d) air drying temperature 90 C. Optical and electron microscopies showed micro particles characterized by acceptable morphology and narrow dimensional distribution. In vivo tests carried out in greenhouse tomato plants, cv. Pullrex Bio, contaminated with a bacterial suspension of Pseudomonas syringae pv. tomato (106 CFU/ml), demonstrated that HPMCP-GA microparticles were able to significantly reduce the Pst epiphytic population showing an activity comparable to that obtained by copper salts. Biocompatible spray-dried microparticles with good activity were obtained and allowed the formulation of innovative products useful to reduce phytotoxicity and risk of copper resistance in plant pathogens associated with the frequent agricultural use of cupric compounds
Cellulose nanocrystals from Actinidia deliciosa pruning residues combined with carvacrol in PVA_CH films with antioxidant/antimicrobial properties for packaging applications
No full textKiwi Actinidia deliciosa pruning residues were here used for the first time as precursors for the extraction of high performing cellulose nanocrystals (CNC) by applying a bleaching treatment followed by an acidic hydrolysis. The resultant cellulosic nanostructures, obtained by an optimize extraction procedure (0.7% wt/v two times of sodium chlorite NaClO2) followed by an hydrolysis step, were then used as reinforcements phases in poly(vinyl alcohol) (PVA) blended with natural chitosan (CH) based films and also combined, for the first time, with carvacrol used here as active agent. Morphological and optical characteristics, mechanical response, thermal and migration properties, moisture content and antioxidant and antimicrobial assays were conducted. The morphological, optical and colorimetric results underlined that no particular alterations were induced on the transparency and color of PVA and PVA_CH blend by the presence of CNC and carvacrol, while they were able to modulate the mechanical responses, to induce antioxidant activities maintaining the migration levels below the permitted limits and suggesting the possible application in industrial sectors. Finally, inhibitions on bacterial development were detected for multifunctional systems, suggesting their protective function against microorganisms contamination
Difesa biologica contro PSA: potenzialità del Bacillus amyloliquefaciens.
Full text linkIn Italia, Pseudomonas syringae pv.
actinidiae (PSA), agente causale
del cancro batterico dell’actinidia
(Fig. 1), a partire dal 2008 (Balestra et
al., 2008; 2009) è stato facilitato nella
sua rapida diffusione soprattutto a
causa del commercio di materiale di
propagazione privo di adeguate verifiche,
sia per le ridotte conoscenze relative
alla sua biologica/epidemiologia
e, conseguentemente, alle opportune
pratiche agronomico-colturali e fitosanitarie
da adottare. In questi anni le
strategie di difesa adottate nei confronti
di questo batterio spesso non sono
state soddisfacenti; solo da alcuni anni
si è preso coscienza dell’importanza e
della necessità di un impiego corretto,
costante e preventivo dei sali di rame,
ma, in assenza di ciò, anche in concomitanza
di situazioni climatiche particolarmente
avverse, come le gelate
della scorsa primavera, quest’anno è
stata registrata una recrudescenza dei
danni causati da PSA
Pseudomonas syringae pv. actinidiae: ecology, infection dynamics and disease epidemiology
No full textSince 2008, the kiwifruit industry has been devastated by a pandemic outbreak of Pseudomonas syringae pv. actinidiae (Psa), the causal agent of bacterial canker. This disease has become the most significant limiting factor in kiwifruit production. Psa colonizes different organs of the host plant, causing a specific symptomatology on each of them. In addition, the systemic invasion of the plant may quickly lead to plant death. Despite the massive risk that this disease poses to the kiwifruit industry, studies focusing on Psa ecology have been sporadic, and a comprehensive description of the disease epidemiology is still missing. Optimal environmental conditions for infection, dispersal and survival in the environment, or the mechanisms of penetration and colonization of host tissues have not been fully elucidated yet. The present work aims to provide a synthesis of the current knowledge, and a deeper understanding of the epidemiology of kiwifruit bacterial canker based on new experimental data. The pathogen may survive in the environment or overwinter in dormant tissues and be dispersed by wind or rain. Psa was observed in association with several plant structures (stomata, trichomes, lenticels) and wounds, which could represent entry points for apoplast infection. Environmental conditions also affect the bacterial colonization, with lower optimum values of temperature and humidity for epiphytic than for endophytic growth, and disease incidence requiring a combination of mild temperature and leaf wetness. By providing information on Psa ecology, these data sets may contribute to plan efficient control strategies for kiwifruit bacterial canker
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