1,720,959 research outputs found
Sviluppo di acaricidi ecologici per un'apicoltura sostenibile
No full textThe honeybee (Apis mellifera) is widely recognized as one of the most crucial pollinators for maintaining biodiversity. However, in recent decades, honeybee populations have experienced a significant decline, primarily due to Varroa destructor, an ectoparasitic mite capable of causing colony collapse within months if left untreated. In addition to mechanical damage, Varroa acts as a vector for severe viral infections, further exacerbating honeybee losses.
Current control measures, while partially effective, are increasingly limited by the development of resistance and environmental contamination. Among these, soft acaricides-natural compounds such as organic acids (e.g., oxalic acid) and essential oils (e.g., thymol, camphor, eucalyptol, and menthol)-are widely used to counteract this parasite. These substances offer advantages in efficacy and safety, with reduced risks of resistance development and hive product contamination compared to synthetic acaricides. However, a common limitation of soft acaricides is their dependence on frequent applications. Long-lasting formulations capable of sustaining active agent release for up to 21 days -the reproductive cycle of varroa- could address these challenges.
This research focused on the development and evaluation of long lasting innovative formulations for the delivery of oxalic acid and essential oils.
For oxalic acid, hydrophilic polymer-based gels incorporating xanthan gum and micronized silica were designed to ensure chemical stability and controlled release under acidic conditions. Preliminary in vivo evaluation studies showed a reduction on Varroa infestation levels (approximately 60%), with the added benefit of making the application easier. Additionally, silica sol-gel matrices were explored as an alternative delivery platform. These matrices achieved sustained release and demonstrated good in vivo efficacy (~70%), combining ecological safety with practical effectiveness. The results obtained are promising, and further in vivo experiments will need to be carried out.
For thymol, silica sol-gel matrices were evaluated to develop a delivery system capable of releasing the compound over 28 days. Formulation studies identified triacetin as a promising cosolvent, mitigating thymol volatilization, and enabling sustained release under hive-like conditions. Initial in vivo trials demonstrated moderate efficacy, with environmental factors such as temperature variability and colony health identified as key determinants. In vivo studies show a good efficacy (~60%). Comparisons with the commercial product Apiguard® highlighted the advantages of single-application formulations.
Mesoporous silica materials were also investigated for the controlled delivery of volatile compounds, including thymol, menthol, camphor, and eucalyptol. Silica-based carriers, particularly SilSol®, proved highly effective in maintaining thymol release. SilSol® emerged as the optimal carrier due to its cost-effectiveness, regulatory approval, and ability to stabilize thymol in its amorphous form. Field trials of thymol-loaded SilSol® formulations demonstrated efficacy (~75%) comparable to that of Apiguard®, with the added benefits of prolonged release from a single application, reduced volatilization losses, and strong acceptance by bees.
The findings presented in this thesis contribute to the advancement of sustainable apicultural practices by offering innovative pest management solutions that prioritize both efficacy and ecological balance. These developments represent a significant step forward to ensure the health and resilience of honeybee populations
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
A novel mertansine conjugate for acid-reversible targeted drug delivery validated through the Avidin-Nucleic-Acid-NanoASsembly platform
Get PDF: In targeted cancer therapy, antibody-drug-conjugates using mertansine (DM1)-based cytotoxic compounds rely on covalent bonds for drug conjugation. Consequently, the cytotoxic DM1 derivative released upon their proteolytic digestion is up to 1000-fold less potent than DM1 and lacks a bystander effect. To overcome these limitations, we developed a DM1 derivative (keto-DM1) suitable for bioconjugation through an acid-reversible hydrazone bond. Its acid-reversible hydrazone conjugate with biotin (B-Hz-DM1) was generated and tested for efficacy using the cetuximab-targeted Avidin-Nucleic-Acid-NanoASsembly (ANANAS) nanoparticle (NP) platform. NP-tethered B-Hz-DM1 is stable at neutral pH and releases its active moiety only in endosome/lysosome mimicking acidic pH. In vitro, the NP/Cetux/B-Hz-DM1 assembly showed high potency on MDA-MB231 breast cancer cells. In vivo both B-Hz-DM1 and NP/Cetux/B-Hz-DM1 reduced tumor growth. A significantly major effect was exerted by the nanoformulation, associated with an increased in situ tumor cell death. Keto-DM1 is a promising acid-reversible mertansine derivative for targeted delivery in cancer therapy
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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