1,720,967 research outputs found
Verification of authenticity and fraud detection in South African honey using NIR spectroscopy
No full textThe South African honey industry will benefit from a reliable method that can verify authenticity as well as detect fraudulence of honey that is on the market. This work presents the use of near-infrared (NIR) spectroscopy in combination with chemometrics as a fast and relatively inexpensive method to discriminate between authentic South African and imported and/or adulterated honey. A supervised chemometric approach was followed on NIR spectra collected from genuine South African honey, as well as intentionally adulterated honeys with sugar solutions (glucose and fructose) and also cheap imported honey. By using partial least squares discriminant analysis (PLS-DA), overall classification accuracies of between 93.3% and 99.9% were obtained when using three different NIR instruments (a laboratory instrument, as well as a portable and a mobile instruments). The usefulness of NIR spectroscopy for accurate honey classifications, regardless the instrument specifications, are demonstrated
Identification of growth related quantitative Trait Loci within the abalone using comparative microsatellite bulked segregant analysis
Full text linkThesis (PhD (Genetics))--Stellenbosch University, 2010.ENGLISH ABSTRACT: The South African abalone, Haliotis midae, is a commercially valuable mollusc and is
mostly exported to the Far East. Genetics research on H. midae has increased
substantially since a genetic improvement programme was introduced in 2006 by
collaboration between Stellenbosch University, government and industry partners. The
development of molecular markers, QTL-mapping, gene-expression and genome
manipulations are the main focuses of the research currently being conducted. The end
goal is to create high quality and fast growing animals for the industry. The present study
focused on the development of microsatellite markers and the detection of quantitative trait
loci (QTL) affecting growth traits (shell length, shell width, wet weight) in this species. A
combination of three methods, namely selective genotyping and bulked segregant analysis
(pooling analysis), single marker regression and interval mapping were used to identify
putative QTL in two full-sib families from two different farmed locations. Additional methods
and protocols were developed that can assist the industry in other molecular research
aspects. A total of 125 microsatellite loci were characterised. A total of 82 of these loci
were isolated using second generation sequencing, a first for any abalone species. A
preliminary, low-density framework linkage map was constructed containing 50 loci that
mapped to 18 linkage groups. The observed genome length was 148.72cm with coverage
of ±47%. QTL analyses revealed two putative QTL for shell width and wet weight, with
17% and 15% variance explained, that mapped on one linkage group in the first family and
three putative QTL, for shell length, shell width and wet weight, with 33%, 28.5% and
31.5% variance explained, that mapped on one linkage group in the second family.
Additional methods and protocols developed include an automated high-throughput DNA
isolation protocol, a real-time PCR assay for H. midae x H. spadicea hybrid verification, a
triploid verification microsatellite assay and a pre- and post-PCR multiplex setup and
optimisation protocol. Future studies focussing on QTL and marker assisted selection
(MAS) should verify the QTL found in this study and also utilise additional family structures
and determine QTL-marker phase within the commercial populations.AFRIKAANSE OPSOMMING: Die Suid-Afrikaanse perlemoen, Haliotis midae, is ’n kommersieel waardevolle
weekdier en word hoofsaaklik na die Verre-Ooste uitgevoer. Genetiese navorsing op H.
midae het aansienlik toegeneem sedert ’n genetiese verbeteringsprogram in 2006 deur
samewerking tussen die Universiteit van Stellenbosch, die regering en industrievennote
ingebring is. Die ontwikkeling van molekulêre merkers, KEL-kartering, geen-uitdrukking en
genoom manipulasies is die hooffokusse van die navorsing wat tans uitgevoer word. Die
einddoel is om hoë kwaliteit en snelgroeiende diere vir die industrie te skep. Die huidige
studie het op die ontwikkeling van mikrosatelliet merkers en die opsporing van
groeiverwante (skulplengte, -breedte en nat gewig) kwantitatiewe eienskap lokusse (KEL)
in hierdie spesie gefokus. ’n Kombinasie van drie metodes, naamlik selektiewe
genotipering en versamelde segregaat analise (samevoegingsanalise), enkel merker
regressie en intervalkartering is gebruik om waarskynlike KEL in twee vol-sibbe families
van twee verskillende produksiegebiede te identifiseer. Aanvullende metodes en protokolle
is ontwikkel wat die industrie in ander molekulêre navorsingsaspekte kan ondersteun. ’n
Totaal van 125 mikrosatelliet lokusse is beskryf. ’n Totaal van 82 van hierdie lokusse is
deur die gebruik van derde generasie volgordebepaling geïsoleer, ’n eerste vir enige
perlemoen spesie. ’n Voorlopige, laedigtheid raamwerkkoppelingskaart is saamgestel met
50 lokusse wat op 18 koppelingsgroepe gekarteer is. Die waarneembare genoomlengte
was 148.72cm met ’n dekking van ±47%. KEL-analises het twee waarskynlike KEL vir
skulpbreedte en nat gewig blootgelê wat 17% en 15% variasie verduidelik en is op een
koppelingsgroep in die eerste familie gekarteer asook drie waarskynlike KEL, vir
skulplengte, -breedte en nat gewig wat 33%, 28.5% en 31.5% variasie verduidelik en is op
een koppelingsgroep in die tweede familie gekarteer. Aanvullende metodes en protokolle
wat ontwikkel is, sluit ’n geoutomatiseerde hoë-deurgang DNS-isolasieprotokol, ’n intydse
PKR-proef vir H. midae x H. spadicea hibried verifikasie, ’n triploïed verifikasie
mikrosatellietproef en veelsoortige pre- en post-PKR opstelling en optimaliseringsprotokol
in. Toekomstige studies wat fokus op KEL en merker ondersteunde seleksie (MOS)
behoort die KEL wat in hierdie studie gevind is te verifieer en ook bykomende familie
strukture te benut om KEL-merker fases binne die kommersiële populasie te bepaal.Doctora
Molecular analysis of genetic variation and relationships within the population of abalone (Haliotis midae) at the Sea Plant Products abalone hatchery, Hermanus, R.S.A.
Full text linkThesis (MSc)--University of Stellenbosch, 2004.ENGLISH ABSTRACT: The species Haliotis midae is the only commercially exploitable abalone
species of the six found in the South African coastal waters. This species is
under substantial pressure from both legal and illegal harvesters, to such an
extent that it could be commercially extinct within four years. Efforts to
alleviate the pressures on the natural populations of both illegal and legal
harvesting are being made. The genetic management systems for abalone
farming and ranching activities should be carefully evaluated. The loss of
genetic diversity and the risks of contaminating the gene pools of natural
populations in the vicinity of a farm should be minimized. Genetic evaluation
studies will be at great importance to acquire the necessary data needed for
genetic diversity and differentiation analysis.
The aim at this study was to develop species-specific microsatellite DNA
markers to assess the genetic diversity and differentiation within and between
the brood stock and commercial stock of the Sea Plant Products abalone farm
(Hermanus, Republic of South Africa) and natural populations related to the
brood stock. The species-specific DNA markers were also used for parentage
assignments within the tarm population (first for abalone) and preliminary OTL
(quantitative trait loci)-discovery analysis studying growth rate segregation.
Samples were taken of the farm's brood stock and commercial stock (Rows 2,
3, 4) as well as from two natural populations (Saldanha Bay and Black Rock)
related to the brood stock. Various statistical parameters and software
packages were used to assess genetic diversity and differentiation, to infer
parentage and to look for OTL's.
Eight species-specific microsatellite DNA markers were designed and used
for data analysis. Data analysis showed a loss at genetic diversity from the
brood stock to the commercial stock caused by the subdivision of the original
brood stock into rows and the differential contributions of parents to the
offspring. No genetic differentiation (Fst) was detected between the farm and natural populations, except for the offspring of Row2. levels of inbreeding
(ns) were high for all loci within the populations. Thirty-eight percent of all
studied offspring were confidently assigned to a couple. The preliminary QTldiscovery
suggested the segregation of a number of alleles and genotypes
with growth rate.
The study concluded that the commercial abalone population of the Sea Plant
Products abalone farm holds no threat to the disruption of the genetic diversity
of the natural populations. It is proposed that the farm implement a rotational
breeding program to increase the genetic diversity of the commercial
population. Any newly acquired brood stock must be profiled before their
introduction into the breeding program to assess the influence of the animals
on the current levels of genetic diversity within the farm. The accuracy and
reliability of parentage assignments and QTl-discovery need to be optimised
by adding more loci and sampling more animals or even by trying and
developing new methods.AFRIKAANSE OPSOMMING: Van die ses perlemoen spesies wat langs die Suid-Afrikaanse kus gevind
word, is die spesie Haliotis midae die enigste een wat van kommersiële
belang is. Wettige, sowel as onwettige versameling, plaas hierdie spesie
onder sulke geweldige druk dat dit dalk binne vier jaar verlore kan wees vir
die kommersiële bedryf. Verskeie strategieë word tans geïmplimenteer om
hierdie druk te verlig. Die genetiese bestuurstrategieë binne perlemoen plase
moet deeglik ondersoek word. Die verlies aan genetiese diversiteit en die
moontlikheid vir die kontaminering van die natuurlike populasies in die
omgewing van die plaas se geenpoel, moet uitgeskakel word. Genetiese
evaluasies sal van groot belang wees om die nodige data vir genetiese
diversiteit- en differensiasie-analises te verkry.
Die doel van die studie was om spesies-spesifieke mikrosatelliet DNA
merkers te ontwikkel wat gebruik sou word om die genetiese diversiteit en
differensiasie binne en tussen die broei diere en die kommersiële diere van
Sea Plant Products se perlemoen plaas (Hermanus, Republiek van Suid-
Afrika) en die natuurlike populasies wat verwant is aan die broei diere, te
bepaal. Die spesies-spesifieke DNA merkers is ook vir ouerskap-bepalings
binne die plaas se populasie gebruik, asook vir voorlopige OTL (quantitative
trait locI) - ontdekking met betrekking tot groeitempo segregasie.
Monsters van die plaas se broei diere en kommersiële diere (Ry 2, 3, 4)
asook van twee natuurlike populasies (Saldanha Baai en Black Rock) wat
verwant is aan die broei diere, is geneem. 'n Verskeidenheid van statistiese
parameters en sagteware pakette is vir die genetiese diversiteit- en
differensiasie-analises, vir ouerskap-bepalings en vir die opspoor van OTL's
gebruik.
Agt spesies-spesifieke mikrosatelliet DNA merkers is ontwerp en toe gebruik
vir die data analises. 'n Verlies aan genetiese diversiteit vanaf die broei diere
na die kommersiële diere is deur die data analises uitgewys. Dit is veroorsaak deur die verdeling van die oorspronklike broei diere in rye en die
differensiële bydraes deur die ouers na die nageslag. Geen genetiese
differensiasie (Fst) is tussen die plaas se populasie en die natuurlike
populasies gevind nie, maar die nageslag van Ry 2 het wel differensiasie
getoon. Die vlakke van inteling (Fis) was hoog oor alle lokusse binne alle
populasies. Agt-en-dertig persent van die nageslag wat bestudeer is, was
suksesvol met 'n ouerpaartjie geassosieer. Die voorlopige OTL-ontdekking
studie toon die potesiële segregasie van 'n aantal allele en genotipes saam
met groeitempo.
Die bevindinge van die studie is dat die kommersiële populasie op die Sea
Plant Products perlemoen plaas, geen bedreiging vir die versteuring van die
natuurlike populasies se genetiese diversiteit inhou nie. Daar is voorgestel
dat die plaas 'n rotasie-basis broeiprogram moet implimenteer om sodoende
die genetiese diversiteit van die kommersiële populasie te verhoog. Enige
nuwe broei diere se genetiese profiel moet ook voor die tyd ondersoek word
om te sien wat se effek hierdie diere op die huidige genetiese diversiteit van
die kommersiële populasie sal hê. Die akkuraatheid en betroubaarheid van
die ouerskap-bepalings en OTL-ontdekking moet optimiseer word deur of
meer lokusse te bestudeer, of meer diere in analises te gebruik of selfs om
nuwe tegnieke te probeer of te ontwikkel
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
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
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
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