102,928 research outputs found
PLOIDY MANIPULATION FOR GENETIC IMPROVEMENT IN SOME MEDITERRANEAN FRUIT CROPS
No full textIl miglioramento genetico ha come obiettivo la selezione di nuovi genotipi con caratteristiche superiori. Metodi convenzionali basati sull’ibridazione e metodi biotecnologici (ibridazione somatica, trasformazione genetica, manipolazione della ploidia, etc.) vengono utilizzati per creare nuova variabilità. Le biotecnologie forniscono potenti strumenti per il miglioramento genetico, per esempio, l'ottenimento di aploidi permette di ottenere linee omozigoti da parentali eterozigoti in un solo atto, riducendo in modo significativo il tempo necessario rispetto ai metodi convenzionali. Per quanto riguarda le specie legnose, caratterizzate spesso da auto-incompatibilità, lungo periodo giovanile ed alta eterozigosi, questa è l’unica tecnica per ottenere linee omozigoti. Le piante aploidi rivestono un elevato interesse per studi di genomica, per mutazioni, analisi genetica, mappatura genetica e trasformazione genetica.
Questa ricerca ha avuto come obiettivo l’induzione di embriogenesi gametica in due importanti specie mediterranee: il mandorlo (Prunus dulcis Mill), tramite coltura in vitro di antere, ed il mandarino (Citrus reticulata Blanco), mediante coltura di microspore isolate. Inoltre, sono stati condotti esperimenti per indurre duplicazione cromosomica in nespolo (Eriobotrya japonica (Thunb.) Lindl.) al fine di ottenere genotipi con diversi livelli di ploidia. Gli esperimenti sono stati condotti nel 2014, 2015 e 2016 presso l’Università degli Studi di Palermo (UNIPA) e l'Instituto Valenciano de Investigaciones Agrarias (IVIA).
Per quanto riguarda la coltura di antere di mandorlo, è stata ottenuta la formazione di calli e la produzione di embrioni omozigoti tramite embriogenesi diretta. Inoltre, la rigenerazione di embrioni è stata ottenuta, per la prima volta, anche a partire da microspore isolate di ‘Mandarino Tardivo di Ciaculli’.
I risultati ottenuti hanno consentito di indurre con successo l'embriogenesi gametica con produzione di rigeneranti omozigoti in mandorlo e mandarino, due specie estremamente recalcitranti a questa tecnica.
Inoltre, un altro strumento biotecnologico (la manipolazione della ploidia) è stato applicato con l’obiettivo di implementare il programma di miglioramento genetico del nespolo dell’IVIA.
Le piante poliploidi hanno un elevato interesse per questa specie, in quanto potrebbero consentire la produzione di genotipi apireni, attraverso la diretta utilizzazione di triploidi o tramite ibridazione tra tetra e diploidi. Con l'obiettivo di ottenere nuovi genotipi con diversi livelli di ploidia (poliploidi), è stata applicata una soluzione di colchicina su semi non germinati di nespolo al fine di indurre duplicazione cromosomica. Un totale di tre triploidi (3x) ed un tetraploide (4x) sono stati così ottenuti.Plant breeding is focused on selection of new genotypes with improved traits. Conventional methods based on hybridization and those based on biotechnology (somatic hybridization, genetic transformation, ploidy manipulation, etc.) are used to create novel genetic variations. Biotechnology provides powerful tools for plant breeding, for instance, haploid technology allows achievement of homozygous lines from heterozygous parents in one step, which reduces significantly the time required by conventional methods. Concerning woody species, characterized by self-incompatibility, long juvenile period and high degree of heterozygosity, this technique is the only way to get homozygous lines. Haploid plants are of great interest for breeding and genomic studies, being used in mutation research, genetic analysis, genome mapping and gene transfer. Gametic embryogenesis, based on cellular totipotency, produces an embryo from an immature gamete, by switching its developmental pathway from gametophytic to sporophytic.
This research is focused on inducing gametic embryogenesis in two important Mediterranean fruit crops: almond (Prunus dulcis Mill.) via in vitro anther culture and mandarin (Citrus reticulata Blanco) via isolation and microspore culture. Also ploidy manipulation was applied to loquat (Eriobotrya japonica (Thunb.) Lindl.) for getting genotypes whit different ploidy levels. The experiments were carried out through years 2014, 2015 and 2016 at the ‘Università degli Studi di Palermo’ (UNIPA) as well as at the ‘Instituto Valenciano de Investigaciones Agrarias’ (IVIA).
Regarding the almond anther culture, formation of calli and production of embryos was achieved through the direct embryogenesis route. On then other hand, early embryo regeneration is reported, for the first time, from isolated microspore culture of mandarin, ‘Mandarino Tardivo di Ciaculli’.
Our results report the evidence of gametic embryogenesis and the production of homozygous regenerants in almond and mandarin, two species extremely recalcitrant to microspore embryogenesis. However, the results are affected by many factors that need further studies to better understand the embryogenic development and to increase the rate of embryo achievement.
Moreover, another biotechnological tool (ploidy manipulation) was also applied for implementing the IVIA loquat breeding program. Polyploid plants are of great interest in this species, due to its potential for producing seedless genotypes via direct use of triploids or crosses between tetra and diploids. Aimed at obtaining new loquat genotypes, with different ploidy levels (polyploids), colchicine was applied to seeds before germination, to induce chromosome duplication. A total of three triploids (3x) and one tetraploid (4x) were obtained
Bibliographie Hilarion G. Petzold 1958 – 2009 mit Anhang als Einführung
No full textDieses Archiv enthält die Gesamtbibliographie der Werke des Autors nebst einiger Texte „Über H. G. Petzold“ im Schlussteil der Bibliographie sowie einen Anhang mit einer Einführung in die Architektur des Werkes in seinem wissenslogischen Aufbau als Ausarbeitung seines „Tree of Science Modells“ (2007).This archive contains the complete bibliography of the author and some texts about H. G. Petzold, moreover an epilogue with an introduction to the architecture of the works in its epistemological structure and composition and as an elaborations of Petzold’s „Tree of Science Modell (2007).https://www.fpi-publikation.de/polyloge/01-2009-petzold-h-g-gesamtbibliographie-h-g-petzold-1958-2009-updating-november2009/peerReviewedpublishedVersio
Dispelling the Myths Behind First-author Citation Counts
No full textWe 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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3346: Samuel G. Freedman, author, 2013
No full textPhotograph of author Samuel G. Freedman, at NT Daily Slash meeting in the Mayborn School of Journalism at UNT
The Right to Strike under the United States Constitution: Theory, Practice, and Possible Implications for Canada
No full textAnswering critics of the Canadian Supreme Court's judgment in B.C. Health, the author argues that the Court laid the foundation for a principled and durable doctrine protecting constitutional labour rights, one that goes directly to the heart of the matter — the inequality of workers’ power in the employment relation. In the author’s view, two paths could lead from B.C. Health to the recognition of Charter protec- tion for a right to strike: one that treats the right as an accessory to col- lective bargaining, and one that upholds the right directly on the basis of the Charter values of equality and participation. The author supports the latter approach, contending that constitutional rights should be defined in relation to fundamental values, in a way that is not contingent on time-bound or fact-sensitive assessments about the role of strikes within a particular collective bargaining regime. Although a Charter right to strike may involve the courts in difficult choices about when to defer to legislative policy decisions, and courts may lack the institutional capac- ity to deal effectively with labour law issues, the author points out that judges can look to ILO standards for expert guidance. Noting that the U.S. experience in this area might be of considerable use to Canadians, the author concludes by providing an overview of American case law concerning a constitutional right to strike.Peer reviewe
G-Rank: Unsupervised Continuous Learn-to-Rank for Edge Devices in a P2P Network
No full textRanking algorithms in traditional search engines are powered by enormous training data sets that are meticulously engineered and curated by a centralized entity. Decentralized peer-to-peer (p2p) networks such as torrenting applications and Web3 protocols deliberately eschew centralized databases and computational architectures when designing services and features. As such, robust search-and-rank algorithms designed for such domains must be engineered specifically for decentralized networks, and must be lightweight enough to operate on consumer-grade personal devices such as a smartphone or laptop computer. We introduce G-Rank, an unsupervised ranking algorithm designed exclusively for decentralized networks. We demonstrate that accurate, relevant ranking results can be achieved in fully decentralized networks without any centralized data aggregation, feature engineering, or model training. Furthermore, we show that such results are obtainable with minimal data preprocessing and computational overhead, and can still return highly relevant results even when a user’s device is disconnected from the network. G-Rank is highly modular in design, is not limited to categorical data, and can be implemented in a variety of domains with minimal modification. The results herein show that unsupervised ranking models designed for decentralized p2p networks are not only viable, but worthy of further research.https://github.com/awrgold/G-RankComputer Scienc
Author inscription in The Chinese slave-girl: a story of woman's life in China
No full textThis edition includes a gift inscription by author Rev. J.A. Davis, "To Rev. A. G. Russell with the warmest regards of the author J.A. Davis."Davis, John Agnell, 1839-1897
Wissenschaftliche Bibliographie Hilarion G. Petzold 1958 – 2014 mit Anhang von 2007 als Einführung
No full textDieses Archiv enthält die Gesamtbiliograpie der Werke des Autors bis Dez. 2013 nebst einiger Texte „Über H. G. Petzold“ und einen Anhang mit einer Einführung in die Struktur des Werkes in seinem wissenslogischen Aufbau als Ausarbeitung seines „Tree of Science Modells“ (2007).This archive contains the complete bibliography of the author up to Dec. 2013 and some texts about H. G. Petzold, moreover an appendix with an introduction to the structure of the work in its epistemological structure and composition as an elaborations of Petzold’s „Tree of Science Modell (2007).https://www.fpi-publikation.de/polyloge/01-2014-petzold-h-g-2014-wissenschaftliche-gesamtbibliographie-1958-2014/peerReviewedpublishedVersio
The construction of Karen Karnak: The multi-author-function
No full textThis thesis is situated within the comparatively recent developments of Web 2.0 and the emergence of interactive WikiMedia, and explores the mode of authorship within a Read/Write culture compared to that of a Read/Only tradition. The hypothesis of this study is that the role of the audience has become merged with the author, and as such, represents new functions and attributes, distinct from a more conventional concept of authorship, in which the roles of audience and author are more separate. Read/Write and participatory culture, as defined by this study, is focused on collaboration, and includes the influences of D.I.Y. culture, Open-Source practices and the production of text by multiple authors. Multi-authorship presents a re-thinking of several concepts which support the notion of the individual author, since the focus of multi-authorship is not on attribution and ownership of a finished text, but on the continued malleability of a text. Modes of multi-authorship, demonstrated in the use of the pseudonyms Alan Smithee and Karen Eliot, represent declarative authors whose names signify multiple origins, whilst concurrently indicating a distinct body of work. The function of these names form an important context to this study, since primary research involves the construction of an experimental mode of multi-authorship utilising WikiMedia technology and the interaction of thirty nine participants, who are invited to create a body of work under the collective pseudonym Karen Karnak. The data generated by this experiment is analysed using aspects of Michel Foucault's author-function to identify and determine power structures inherent in the WikiMedia context. The interplay of power structures, including concepts such as identity, ownership and the body of work, affect the resulting mode of authorship and contribute to the construction of Karen Karnak, suggesting further areas of research into the emerging multi-author
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