1,720,973 research outputs found
Influence of Mechanical Aspects of Distribution on Viability of the Biological Control Agent Steinernema carpocapsae.
No full textThe distribution of entomopathogenic nematodes (EPNs) for pest control in organic and conventional agriculture is usually carried out with traditional boom sprayers normally used for the distribution of pesticides. Nevertheless there is a reasonable possibility that this operation may induce a state of stress due to sudden pressure changes and mechanical stress, especially during the passage through the pump and nozzles or as a consequence of the effect of hydraulic or pneumatic agitation inside the tank.
This work aims to evaluate the effects of some mechanical distribution parameters on the viability of the entomopathogenic nematode Steinernema carpocapsae Weiser which may become significant during the distribution.
To assign the mechanical effects to specific components of the distribution, liquid suspensions of the nematode were subjected to different levels of static pressure, and various conditions of agitation and distribution using different types of nozzles.
Preliminary results show no significant effect of static pressure on the viability of nematodes. The passage through the nozzles and the use of a elastic rotor pump induces a 7% decrease in viability, but no difference was detected between different nozzles, while the intensity of hydraulic agitation appeared to affect the nematodes viability
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
Foliar application of nematodes for noctuid moths control in spinach with traditional boom sprayer
No full textEffetti della distribuzione meccanica sulla vitalità del nematode entomopatogeno Steinernema Carpocapsae
No full textLa distribuzione di nematodi entomopatogeni (EPN) nel controllo di fitofagi in agricoltura
biologica e convenzionale è abitualmente effettuata con le comuni irroratrici impiegate per la
distribuzione di agrofarmaci. La ricerca si propone di valutare la risposta biologica, in termini
di vitalità, del nematode entomopatogeno Steinernema carpocapsae (Weiser) sottoposto a diversi effetti di stress meccanico che possono riscontrarsi nella irrorazione. In particolare, sospensioni liquide del nematode sono state sottoposte a diversi livelli di pressione statica e a diverse condizioni di agitazione e distribuzione impiegando diverse tipologie di ugelli. I risultati preliminari non mostrano un effetto significativo della pressione statica (fino a 14 bar) sulla vitalità dei nematodi. Il passaggio attraverso la pompa a girante flessibile e gli ugelli induce una diminuzione del 7% della vitalità, ma nessuna differenza si rileva tra gli ugelli utilizzati. La prova di agitazione combinata con lo svuotamento del serbatoio ha mostrato che una più bassa intensità di riciclo, realizzata, se necessario, riducendo la velocità della presa di potenza riduce la mortalità dei nematodi. In tutti i casi la concentrazione dei nematodi in corrispondenza dello svuotamento del serbatoio è stata del 20% superiore a quella iniziale
An Innovative System for Air-Assisted Distribution of Beneficial Organisms on Protected Crops.
No full textThe distribution of chemicals on protected crops is often a critical moment for the operators who are forced to make frequent treatments in an enclosed environment and in the presence of high pesticide concentrations.
The introduction of organic farming techniques improves these aspects but generally requires a substantial commitment of manpower and forces the operator to stay for a long time in environments characterized by temperature and humidity that cause discomfort and fatigue. Increasing the level of mechanization improves the effectiveness of the treatments and it
Experiments were conducted to assess the efficiency of this prototype, the reduction of working time and the possible effect on the viability of organisms distributed. also permits a quicker approach with relevant improvement on workers’ health and safety, particularly in greenhouse crops. We therefore developed a prototype for the distribution of beneficial organisms that can increase the labour productivity and distribution quality on protected crops.
The effectiveness of the distribution has been verified through laboratory and field tests to evaluate the effects of the releasing on viability and fertility of beneficial organisms.
The prototype has been demonstrated to properly perform the releasing of arthropods without compromising the viability and fertility of two species of phytoseiids (Phytoseiulus persimilis and Amblyseius swirskii), whereas in the case of nymphs of the anthocorid Orius laevigatus, the survival immediately after the distribution and the post-release survival (reaching of the adult stage) are influenced by the action of the mechanical device
Technological aspects of Steinernema carpocapsae spray application alone or mixed with Bacillus thuringiensis aizawai in spinach crop
No full textFoliar application of entomopathogenic nematodes (EPN) is generally carried out with traditional boom sprayers. However there is a possibility that this operation may cause physical stress to nematodes due to the action of the mechanical components. Our aim was to evaluate the effects of a spray application, with a conventional hydraulic sprayer, on the viability of Steinernema car-pocapsae (Weiser) in spinach crop. Laboratory tests preceded foliar application in the field to exclude possible effects on the ne-matodes due to the spray equipment. In a field trial, applications of EPN alone and in a mixture with Bacillus thuringiensis Berliner (Bt) subsp. aizawai were carried out evaluating their level of control against noctuid moths in spinach. The biopesticides action was also compared with conventional chemical control. In addition, the interaction from the combination of Bt and EPN was investigated. Results showed that a static pressure up to 14 bar causes no significant damage to S. carpocapsae and that the passage of the nematode through the flat fan nozzles do not affect their viability. Repeated recirculation of nematodes by hydro-ejector did not affect their viability even at high recirculation level (36.9 l/min). In the field trial, treatment with EPN alone and with the mixture EPN+Bt showed no significant differences with respect to the control. Nevertheless, in general these treatments were not significantly different from chemical treatment. The combined application of EPN and Bt showed an additive interaction compared to EPN alone
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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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