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The influence of cell wall bound calcium, cell number and size on the development of mealiness in 'Forelle' pear. Evaluation of X-ray CT and NIR as non-destructive techniques for mealiness detection
Get PDFThesis (PhD)--Stellenbosch University, 2016.ENGLISH ABSTRACT: ‘Forelle’ pear (Pyrus communis L.) is the second most planted pear and the second highest generator of foreign exchange for pears in South Africa. It is favoured for its red blush, melting texture, sweet taste and pear flavour. However, ‘Forelle’ develops mealiness, a floury, soft and dry texture with low extractable juice. Consumers dislike mealy fruit. ‘Forelle’ mealiness has been characterized by a loss of cell to cell binding during ripening in a previous study. This study aimed to further understand the role of cell wall bound and free Ca2+, as well as the cell size and cell number in the development of mealiness in ‘Forelle’. In addition, two non-destructive methods for the detection of mealiness in intact pears were examined.
It was found that free Ca2+ constituted about 49-73% of the total cell Ca2+. Depending on farm origin, mealy fruit contained a lower free Ca2+ concentration compared to non-mealy pears. Plant growth regulators and selective blossom thinning that caused larger cells had a higher mealiness percentage. Scanning electron microscopy revealed larger intercellular spaces for treatments with a higher mealiness incidence. Macro X-ray computed tomography (X-ray CT) showed a higher percentage of defects in the neck of fruit that would become mealy after storage, and after softening. To our knowledge this is a first such finding. Micro (X-ray CT) found that cells of mealy fruit were larger and ellipsoidal in shape while non-mealy cells were smaller and more rounded. Mealiness was also associated with high fruit porosity.
A further study described physicochemical measurements which relate to mealiness. Mealy fruit were mostly larger with a higher total soluble solids (TSS), TSS:TA ratio and lower juice area and juice weight obtained by a confined compression method. Fourier transform near-infrared absorbance spectroscopy (FT-NIR) was employed to determine if spectra could be used to distinguish between mealy and non-mealy fruit using sensory and TSS based schemes. Classification was done using orthogonal partial least squares discriminant analysis (OPLS-DA). This study showed that FT-NIR spectra can indeed be used to discriminate between mealy and non-mealy ‘Forelle’ pears. Two–class (mealy and non-mealy) discriminant analysis produced models with accuracies ranging from 51% to 95%. Mealiness caused an increase in transmittance in specific regions of the spectra. FT-NIR was then evaluated for the quantification of TSS using partial least squares (PLS) regression. Validated models had root mean squared error of prediction (RMSEP) = 0.76-0.94 and relative prediction deviation (RPD) = 1.53-2.17, with the equator blush consistently giving better performance for three farms making the model ideal for hand held FT-NIR applications. External validation results of farm location showed reduced model robustness. The decrease in prediction performance was attributed to the differing TSS ranges in locations and possibly seasons. It is recommended that future studies on FT-NIRs calibration models for ‘Forelle’ use fruit from wide origins with wide TSS ranges over various seasons.AFRIKAANSE OPSOMMING: ‘Forelle’ pere (Pyrus Communis L.) is die tweede mees aangeplante peer en die tweede grootste inkomste genereerder van buitelandse valuta vir pere in Suid Afrika. Dit word verkies vir sy rooi blos, smeltende tekstuur, soet smaak en peer geur. ‘Forelle’ ontwikkel egter ʼn melerige, sagte en droë tekstuur met lae ekstraheerbare sap. Verbruikers hou nie van melerige vrugte nie. ‘Forelle’ melerigheid is in ʼn vorige studie verbind aan die verlies van sel tot sel verbindings gedurende rypwording. Die doel van hierdie studie was om die rol van selwand gebinde en vrye Ca2+, asook selgrootte en selgetal in die ontwikkeling van melerigheid in ‘Forelle’ te verstaan. Laastens is twee nie-destruktiewe metodes vir die opsporing van melerigheid in intakte pere ondersoek.
Daar is gevind dat vrye Ca2+ omtrent 49-73% van die totale sel Ca2+ uitmaak. Afhangend van die boord van oorsprong, het melerige pere ʼn laer konsentrasie van vrye Ca2+ bevat, in vergelyking met nie melerige pere. Plant groeireguleerders en selektiewe bloeiseluitdunning wat groter selle veroorsaak het, het ʼn hoër persentasie van melerige vrugte gehad. Skanderings elektron mikroskopie openbaar dat groter intersellulêre spasies, in behandelings wat meer melerigheid gehad het, gevind is. Makro X-straal verwerkte tomografie (X-straal VT) het aangedui dat defekpersentasie hoër was in die nek van vrugte wat melerig sou word na opberging, asook na sagwording. Dit is volgens ons kennis die eerste diesulke bevinding. Mikro X-straal VT het gevind dat melerige selle groter en meer ellipsoïdaal in vorm was terwyl nie-melerige selle kleiner en meer rond was. Melerigheid was ook geassosieer met ʼn hoër vrugporositeit.
‘n Verdere studie het die fisikochemiese metings wat ʼn verwantskap toon met melerigheid bepaal. Melerige vrugte was meestal groter vrugte met ʼn hoër persentasie van totale oplosbare vastestowwe (TOVS), TOVS:titreerbare suur verhouding, en ʼn laer sap area en sap gewig wat bepaal was met die begrensde kompressie metode. Fourier getransformeerde naby infrarooi absorpsiespektroskopie (FT-NIR) om te bepaal of spektra benut kan word om tussen melerige en nie-melerige vrugte te onderskei d.m.v. sensoriese en TOVS klassifikasie is gedoen met behulp van ortogonale gedeeltelike laagste kwadraat diskriminant analise (OPLS-DA). Die studie toon dat FT-NIR spektra wel gebruik kan word om tussen melerige en nie-melerige ‘Forelle’ pere te onderskei. Twee–klas (melerige en nie-melerige) diskriminant analises het modelle geproduseer met ʼn akkuraatheid van 51% tot 95%. Melerigheid het ʼn verhoging in transmissie in sekere areas van spektra veroorsaak. FT-NIR is verder geëvalueer vir die kwantifisering van TOVS met die gebruik van gedeeltelike laagste kwadraat (PLS) regressie modelle. Die gevalideerde modelle het gemiddelde kwadraat fout van voorspelling (RMSEP) = 0.76-0.94 en relatiewe voorspellingsafwyking (RPD) = 1.53-2.17 gehad, met die ewenaar bloskant van die vrug wat konsekwent beter presteer het vir drie plase. Dit sou die model ideaal maak vir handgehoude tipe FT-NIR toepassings. Eksterne validasie resultate van plaas posisie toon verlaagte model robuustheid. Die verlaging in voorspellings prestasie was toegeskryf aan die TOVS verspreiding wat verskillend was vir plase en moontlik ook seisoene. Daar word aanbeveel dat toekomstige kalibrasie model studies op ‘Forelle’ vrugte van ʼn wye oorsprong en TOVS verspreidings insluit oor verskeie seisoene.Doctora
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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