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Critical evaluation of the accuracy of the enumeration methodology of Coliforms and E. Coli in water from rivers used for the irrigation of fresh produceBrand, Amanda Salome 12 1900 (has links)
Thesis (PhD)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: The accuracy of methods for the enumeration of coliforms and Escherichia coli present in river
water intended for the irrigation of fresh produce has been critically evaluated to determine whether
the results of the traditional method were reliable in indicating faecal pollution. The potential of
rapid alternative methods were also explored.
Baseline monitoring of the Berg River showed the presence of potential pathogens such as
Salmonella, and also that E. coli levels exceeded international guidelines for the safe irrigation of
minimally processed foods (MPFs) in 20.5% of cases, which indicated faecal intrusion. An
exploratory study into the use of microbiological and physico-chemical parameters in predicting E.
coli numbers, as a rapid alternative to direct enumeration, was conducted. These measurements,
neither individually nor in combination, could accurately predict the E. coli numbers.
The rapid method Colilert-18 was compared against multiple tube fermentation (MTF) for
the enumeration of coliforms and E. coli. Spearman rank correlation coefficients showed that
Colilert-18 had acceptable (r2=0.69) and fair (r2=0.74) correlations with MTF for coliform and E. coli
enumeration, respectively. Bland and Altman statistics were used to determine pollution influence,
and Colilert-18 showed increasing disagreement with MTF at very high concentrations of coliforms
and E. coli.
Bacterial isolates obtained from MTF reactions were identified using biochemical and mass
spectrometry methods. These identifications revealed that the greatest contributors to inaccurate
coliform enumeration by MTF were false negative coliforms which fail to produce gas from lactose.
Numerical biochemical data suggested that these isolates may be able to use other carbohydrates
preferentially over lactose. Inaccurate E. coli enumeration was caused by E. coli strains which
could not utilise lactose or 4-methylumbelliferyl- -D-glucuronide (MUG), as well as non-E. coli
isolates which were able to hydrolyse MUG. The method of transfer of bacteria between MTF
media was also identified as problematic for accuracy.
Monoplex polymerase chain reaction (PCR) differentiation of MTF isolates showed that
detection of the uidA gene showed the greatest accuracy in the detection of E. coli, while the
multiplex PCR protocol for detecting diarrheagenic E. coli pathotypes identified one strain of
enteroaggregative E. coli (EAEC).
A qualitative methodological risk classification was used, in combination with the individual
reactions of MTF isolates, to elucidate their contribution to enumeration inaccuracy and to evaluate
the effect of MUG and Levine-eosin methylene blue (L-EMB) agar. The classification indicated that
inaccurate enumeration of E. coli was more problematic than that of coliforms, but revealed that
the exclusion of MUG from MTF may increase the accuracy of E. coli enumeration. The omission
of L-EMB would have very little effect on E. coli enumeration accuracy. This work confirmed that MTF is fairly reliable in the enumeration of coliforms and E. coli.
Inaccuracies are primarily attributable to atypical organisms which are considered to make up a
small proportion of the total bacterial population. Colilert-18 was shown to be an acceptably
accurate alternative, and its rapid production of results can be highly advantageous in the
monitoring of irrigation water used for MPFs. / AFRIKAANSE OPSOMMING: Die akkuraatheid van metodes vir die telling van kolivorme en Escherichia coli in rivier water,
gebruik vir besproeiing van vars produkte, is krities geëvalueer om vas te stel of die resultate van
tradisionele metodes betroubaar was in die aanduiding van fekale besoedeling. Die potensiaal van
snelle alternatiewe metodes is ook ondersoek.
Basislyn monitering van die Berg River het aangedui dat potensiële patogene soos
Salmonella teenwoordig is, en dat E. coli vlakke internasionale riglyne vir die veilige besproeiing
van minimaal geprosesseerde voedsels (MGVs) oorskry het in 20.5% van gevalle, wat dui op
fekale besmetting. ‘n Ondersoekende studie van die bruikbaarheid van mikrobiologiese en fisieschemiese
parameters in die voorspelling van E. coli getalle, as snelle alternatief tot direkte telling,
is uitgevoer. Hierdie metings kon nie, individueel of in kombinasie, akkurate voorspellings van E.
coli getalle maak nie.
Die snelle metode Colilert-18 is vergelyk met veelvoudige buis fermentasie (VBF) in die
telling van kolivorme en E. coli. Spearman rang korrelasie koëffisiënte het aangetoon dat Colilert-
18 aanvaarbare (r2=0.69) en goeie (r2=0.74) korrelasies met VBF gehad het vir kolivorm en E. coli
tellings, respektiewelik. Bland en Altman statistiek is gebruik om die invloed van besoedeling te
bepaal, en Colilert-18 het afnemende ooreenstemming met VBF getoon by baie hoë kolivorm en E.
coli konsentrasies.
Bakteriële isolate verkry vanaf VBF reaksies is geïdentifiseer met behulp van biochemiese
en massa spektrometrie metodes. Hierdie identifikasies het getoon dat vals-negatiewe kolivorme,
wat nie gas vanaf laktose kan produseer nie, die grootste bydraende faktor is in onakkurate
kolivorm telling deur VBF. Biochemiese data het voorgestel dat hierdie isolate moontlik ander
koolhidrate by voorkeur bo laktose gebruik. Onakkurate E. coli tellings is veroorsaak deur E. coli
isolate wat nie laktose of 4-metielumbelliferiel- -D-glukuronied (MUG) kon verbruik nie, sowel as
nie-E. coli isolate wat wel MUG kon hidroliseer. Die oordrag-metode van bakterieë tussen VBF
media is ook geïdentifiseer as problematies.
Monopleks polimerase ketting reaksie (PKR) onderskeiding van VBF isolate het aangedui
dat opsporing van die uidA geen die grootste akkuraatheid vir die opsporing van E. coli het, terwyl
die multipleks PKR protokol vir die opsporing van diarree-veroorsakende E. coli patotipes een stam
van entero-aggregerende E. coli (EAEC) geïdentifiseer het.
‘n Kwalitatiewe metodologiese risiko klassifikasie is gebruik, in kombinasie met die
individuele reaksies van VBF isolate, om hul bydrae tot telling onakkuraatheid vas te stel. Die
effek van MUG en Levine-eosien metileenblou (L-EMB) agar is ook geëvalueer. Daar is bevind dat
die onakkurate telling van E. coli meer problematies is as dié van kolivorme, maar ook dat die
uitlating van MUG by VBF die akkuraatheid van E. coli tellings kan verhoog. Die uitlating van LEMB
agar sal ‘n ignoreerbare effek hê op E. coli telling akkuraatheid. Hierdie werk het bevestig dat VBF akkuraat is in die telling van kolivorme en E. coli.
Onakkuraathede word primêr toegeskryf aan atipiese organismes, wat beskou word as ‘n klein
proporsie van die totale bakteriële bevolking. Colilert-18 is ‘n aanvaarbaar akkurate alternatief, en
die metode se produksie van snelle resultate kan hoogs voordelig wees in die monitering van
MGVs besproeiingswater.
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Effectiveness of case based method versus traditional lecture in the retention of athletic training knowledgeCarter, Lori D. 15 March 1995 (has links)
Graduation date: 1995
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Does IDA meet the requirements? : Evaluating the method Information Demand AnalysisWass, Sofie, Nyberg, Camilla January 2009 (has links)
<p>This study aims to evaluate the use of the method Information Demand Analysis (henceforth IDA) against an analysis tool. To gain empirical understanding of IDA, the method will be applied to a cooperation process between two business organisations. The research questions of the study are to investigate what can be required of a method, to identify the information demand for the above mentioned cooperation process, and to identify the strengths and weaknesses of the use of IDA.</p><p>Based on a literature study an evaluation framework, which describes what can be required of a method, was developed. The evaluation framework resulted in an analysis tool, which consists of the elements: method content, method user, method context, method validation, the method creator’s requirements, and the wishes and expectations of the business organisations. The use of IDA implied scoping to delimit the problem situation and a workshop to identify the information demand. In order to gain an understanding of the use of the method IDA, and to identify the information demand, the method was applied to a cooperation process between Steel AB and Wood AB. The information demand was later represented in Extended Enterprise Modelling Language (henceforth EEML). Finally, we analysed if and how the elements in the analysis tool were reflected in IDA and identified the strengths and weaknesses of the use of the method.</p><p>The strengths of IDA are that it is general and applicable on different types of business organisations. Furthermore, it has well defined concepts and the possibility of selecting appropriate concepts ensures that it is applicable on different problem situations. The business organisations, which participated in the workshop, found that IDA resulted in a holistic view and increased the understanding for each other. The weaknesses of IDA are lack of documentation of explicitly defined steps, the implications for selecting certain concepts, guidance, and explicitly described notations. Concerning the involved roles, in IDA, we request a description of them, their responsibilities, and the needed knowledge sets and skills for using the method. Since IDA still is under development we had difficulties understanding how our outcome of the method should fulfil the purpose of IDA.</p>
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A mixed method evaluation of the subjective well–being of first–year tertiary students during orientation / Johannes Hendrikus de KockDe Kock, Johannes Hendrikus January 2010 (has links)
The aim of orientation programs at tertiary academic institutions is to introduce newcomers
to the attitudinal and behavioral standards of their new academic and social situation, and
these programs usually have a formal and an informal component. Formal orientation is
officially developed and monitored by the university. Informal orientation is associated with
socially orientated initiation or hazing activities administered by senior students in the
seclusion of hostels and are often not monitored by the university, resulting in human rights
violations such as racial discrimination, physical abuse and psychological bullying. Because
both components of orientation take place during the same time frame and in the same
broader context, orientation programs as a whole have been receiving negative attention and
criticism in the media. Research has, however, also uncovered many positive elements in
orientation programs - in both the formal and informal components. Literature suggests that
universities put in place a high quality formal and informal orientation program to ensure the
well–being of first–year students.
Well–being is regarded as the subjective appraisals that people make about the quality of their
lives based on their experiences, relationships, feelings and overall functioning in life. Two
approaches towards subjective well–being are identified: the first is the hedonic approach,
focusing on emotional well–being (EWB) and is equated to positive feelings, subjective
happiness and satisfaction with life; the second is the eudaimonic approach, focusing on psychological well–being (PWB) and social well–being (SWB) which not only conceptualizes
well–being in terms of meaning and purpose, but also as positive functioning in life on
personal and social levels. The aim of this study was to determine the shifts in well–being of
first–year students during an orientation program (with both the formal and informal
components included) at a tertiary institution and to explore the experiences associated with
these shifts.
A sequential mixed method research design was used where quantitative and qualitative
research approaches were combined to provide an in–depth understanding of the
phenomenon. A convenience sample of first–year hostel residing students (mean age=19
years) was used for the quantitative study. Students completed the Mental Health Continuum
Short Form (MHC–SF) and the Satisfaction With Life Scale (SWLS) before (n=102), during
(n=371) and after (n=358) the orientation program. Twenty–one demographically
representative first–year hostel residing students (mean age=18.5 years) were purposive
selected to participate in the qualitative study consisting of a focus group discussion and
semi–structured in–depth individual interviews which took place after the programs’
completion.
The quantitative results indicated that first–year students’ well–being remained unchanged
before, during and after orientation in all facets except in SWB. First–year students’ SWB
increased practically significantly over the course of the orientation program. The qualitative
findings suggested that first–year students’ well–being fluctuated from high before the
orientation program to low during the program’s initial phase to high again after the
program’s completion. Experiences associated with SWB were perceived to be the central
experience associated with an increase in well–being. Recommendations are made regarding the promotion of the social and personal well–being of first–year students during an
orientation program. / Thesis (M.A. (Clinical Psychology))--North-West University, Potchefstroom Campus, 2011.
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A mixed method evaluation of the subjective well–being of first–year tertiary students during orientation / Johannes Hendrikus de KockDe Kock, Johannes Hendrikus January 2010 (has links)
The aim of orientation programs at tertiary academic institutions is to introduce newcomers
to the attitudinal and behavioral standards of their new academic and social situation, and
these programs usually have a formal and an informal component. Formal orientation is
officially developed and monitored by the university. Informal orientation is associated with
socially orientated initiation or hazing activities administered by senior students in the
seclusion of hostels and are often not monitored by the university, resulting in human rights
violations such as racial discrimination, physical abuse and psychological bullying. Because
both components of orientation take place during the same time frame and in the same
broader context, orientation programs as a whole have been receiving negative attention and
criticism in the media. Research has, however, also uncovered many positive elements in
orientation programs - in both the formal and informal components. Literature suggests that
universities put in place a high quality formal and informal orientation program to ensure the
well–being of first–year students.
Well–being is regarded as the subjective appraisals that people make about the quality of their
lives based on their experiences, relationships, feelings and overall functioning in life. Two
approaches towards subjective well–being are identified: the first is the hedonic approach,
focusing on emotional well–being (EWB) and is equated to positive feelings, subjective
happiness and satisfaction with life; the second is the eudaimonic approach, focusing on psychological well–being (PWB) and social well–being (SWB) which not only conceptualizes
well–being in terms of meaning and purpose, but also as positive functioning in life on
personal and social levels. The aim of this study was to determine the shifts in well–being of
first–year students during an orientation program (with both the formal and informal
components included) at a tertiary institution and to explore the experiences associated with
these shifts.
A sequential mixed method research design was used where quantitative and qualitative
research approaches were combined to provide an in–depth understanding of the
phenomenon. A convenience sample of first–year hostel residing students (mean age=19
years) was used for the quantitative study. Students completed the Mental Health Continuum
Short Form (MHC–SF) and the Satisfaction With Life Scale (SWLS) before (n=102), during
(n=371) and after (n=358) the orientation program. Twenty–one demographically
representative first–year hostel residing students (mean age=18.5 years) were purposive
selected to participate in the qualitative study consisting of a focus group discussion and
semi–structured in–depth individual interviews which took place after the programs’
completion.
The quantitative results indicated that first–year students’ well–being remained unchanged
before, during and after orientation in all facets except in SWB. First–year students’ SWB
increased practically significantly over the course of the orientation program. The qualitative
findings suggested that first–year students’ well–being fluctuated from high before the
orientation program to low during the program’s initial phase to high again after the
program’s completion. Experiences associated with SWB were perceived to be the central
experience associated with an increase in well–being. Recommendations are made regarding the promotion of the social and personal well–being of first–year students during an
orientation program. / Thesis (M.A. (Clinical Psychology))--North-West University, Potchefstroom Campus, 2011.
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Does IDA meet the requirements? : Evaluating the method Information Demand AnalysisWass, Sofie, Nyberg, Camilla January 2009 (has links)
This study aims to evaluate the use of the method Information Demand Analysis (henceforth IDA) against an analysis tool. To gain empirical understanding of IDA, the method will be applied to a cooperation process between two business organisations. The research questions of the study are to investigate what can be required of a method, to identify the information demand for the above mentioned cooperation process, and to identify the strengths and weaknesses of the use of IDA. Based on a literature study an evaluation framework, which describes what can be required of a method, was developed. The evaluation framework resulted in an analysis tool, which consists of the elements: method content, method user, method context, method validation, the method creator’s requirements, and the wishes and expectations of the business organisations. The use of IDA implied scoping to delimit the problem situation and a workshop to identify the information demand. In order to gain an understanding of the use of the method IDA, and to identify the information demand, the method was applied to a cooperation process between Steel AB and Wood AB. The information demand was later represented in Extended Enterprise Modelling Language (henceforth EEML). Finally, we analysed if and how the elements in the analysis tool were reflected in IDA and identified the strengths and weaknesses of the use of the method. The strengths of IDA are that it is general and applicable on different types of business organisations. Furthermore, it has well defined concepts and the possibility of selecting appropriate concepts ensures that it is applicable on different problem situations. The business organisations, which participated in the workshop, found that IDA resulted in a holistic view and increased the understanding for each other. The weaknesses of IDA are lack of documentation of explicitly defined steps, the implications for selecting certain concepts, guidance, and explicitly described notations. Concerning the involved roles, in IDA, we request a description of them, their responsibilities, and the needed knowledge sets and skills for using the method. Since IDA still is under development we had difficulties understanding how our outcome of the method should fulfil the purpose of IDA.
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Evaluation of the SDF method using a customised design flood estimation toolGericke, Ockert Jacobus 12 1900 (has links)
Thesis (MScEng (Civil Engineering))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: The primary aim of this study was to evaluate, calibrate and verify the SDF run-off
coefficients at a quaternary catchment level in the C5 secondary drainage region
(SDF basin 9) and other selected SDF basins in South Africa by establishing the
catchment parameters and SDF/probability distribution-ratios. The probability
distribution-ratios were based on the comparison between the flood peaks
estimated by the SDF method and statistical analyses of observed flow data.
These quaternary run-off coefficients were then compared with the existing
regional SDF run-off coefficients, whilst the run-off coefficient adjustment factors
as proposed by Van Bladeren (2005) were also evaluated.
It was evident from this study that the calibrated run-off coefficients obtained are
spread around those of Alexander (2003), but were generally lower in magnitude.
The adjusted run-off coefficients (Van Bladeren, 2005) had a tendency to
decrease in magnitude with increasing recurrence interval, whilst some of the
adjusted run-off coefficients exceeded unity.
The extent to which the original SDF method overestimated the magnitude and
frequency of flood peaks varied form basin to basin, with the SDF/probability
distribution-ratios the highest in the Highveld and southern coastal regions with
summer convective precipitation. In these regions the flood peak-ratios were
occasionally different by up to a factor of 3 or even more. The southern coastal
regions with winter orographic/frontal precipitation demonstrated the best flood
peak-ratios, varying from 0.78 to 1.63.
The adjusted SDF method results (Van Bladeren, 2005) were only better in 26%
of all the basins under consideration when compared to those estimated by the
original SDF method. On average, the adjusted SDF/probability distribution-ratios
varied between 0.30 and 6.58, which is unacceptable.
The calibrated version of the SDF method proved to be the most accurate in all
the basins under consideration. On average, the calibrated SDF/probability distribution-ratios varied between 0.85
and 1.15, whilst at some basins and individual return periods, less accurate
results were evident.
Verification tests were conducted in catchments not considered during the
calibration process with a view to establish whether the calibrated run-off
coefficients are predictable and to confirm that the method is reliable. The
verification results showed that the calibrated/verified SDF method is the most
accurate and similar trends were evident in all the basins under consideration. On
average, the verified SDF/probability distribution-ratios varied between 0.82 and
1.19, except in SDF basins 6 and 21 where the 5 to 20-year return period flood
peaks were overestimated by 41% and 56% respectively, which is still
conservative.
The secondary aim of this study was to develop a customised, user-friendly
Design Flood Estimation Tool (DFET) in a Microsoft Office Excel/Visual Basic
for Applications environment in order to assess the use and applicability of the
various design flood estimation methods.
The developed DFET will provide designers with a software tool for the rapid
investigation and evaluation of alternative design flood estimation methods either
at a regional or site specific scale. The focus user group of the application will
comprises of engineering technicians, engineering technologist and engineers
employed at civil engineering consultants, not necessarily specialists in the field of
flood hydrology. The DFET processed all the catchment, meteorological
(precipitation) and hydrological (observed flows) data used as input for the various
design flood estimation methods. / AFRIKAANSE OPSOMMING: Die primêre doelwit van die studie was om die SDF-afloopkoëffisiënte op ‘n
kwartinêre opvangsgebiedvlak in die C5-sekondêre dreineringsgebied (SDFopvangsgebied
9) en ander gekose SDF-opvangsgebiede in Suid-Afrika te
evalueer, te kalibreer en te verifieer deur die opvangsgebiedparameters en
SDF/waarskynlikheidsverspreiding-verhoudings vas te stel. Dié
waarskynlikheidsverspreiding-verhoudings was gebaseer op die vergelyking
tussen die vloedpieke soos beraam deur die SDF-metode en statistiese analises
van waargenome vloeidata. Dié kwartinêre afloopkoëffisiënte is met die
bestaande streeksgebonde SDF-afloopkoëffisiënte vergelyk, terwyl die
afloopkoëffisiënt-aanpassingsfaktore soos voorgestel deur Van Bladeren (2005)
ook geëvalueer is.
Dit het duidelik uit die studie geblyk dat die gekalibreerde afloopkoëffisiënte
verspreid rondom die van Alexander (2003) is, maar in die algemeen laer in
omvang. Die aangepaste afloopkoëffisiënte (Van Bladeren, 2005) was geneig om
af te neem in grootte met ‘n toename in die herhalingsperiode, terwyl sommige
afloopkoëffisiënte ‘n waarde van 1 oorskry het.
Die omvang waartoe die oorspronklike SDF metode die grootte en herhaalperiode
van vloedpieke oorskat het, wissel van opvangsgebied tot opvangsgebied, met die
SDF/waarskynlikheidsverspreiding-verhoudings die hoogste in die Hoëveld en
suidelike kusstreke gekenmerk deur konveksie-somerreënval. In hierdie streke het
die vloedpiekverhoudings gereeld verskil tot en met ‘n faktor van 3 of selfs meer.
Die suidelike kusstreke met kenmerkende ortografiese/frontale winterreënval het
oor die beste vloedpiekverhoudings beskik wat gewissel het tussen 0.78 en 1.63.
Die resultate van die aangepaste SDF-metode (Van Bladeren, 2005) was slegs in
26% van al die opvangsgebiede beter as die beramings van die oorspronklike
SDF-metode. Die aangepaste SDF/waarskynlikheidsverspreiding-verhoudings
het, met verwysing na gemiddeldes, tussen 0.30 en 6.58 gewissel, wat
onaanvaarbaar is. Die gekalibreerde weergawe van die SDF-metode was die mees akkurate metode
in al die opvangsgebiede van belang. Die gekalibreerde
SDF/waarskynlikheidsverspreiding-verhoudings het, met verwysing na
gemiddeldes, tussen 0.85 en 1.15 gewissel, terwyl die resultate van sommige
opvangsgebiede en individuele herhalingsperiodes minder akkuraat was.
Verifikasietoetse is uitgevoer in die opvangsgebiede wat nie tydens die
kalibrasieproses gebruik was nie om vas te stel of die gekalibreerde
afloopkoëffisiënte voorspelbaar is en om te bevestig dat die metode betroubaar is.
Die verifikasieresultate het getoon dat die gekalibreerde/geverifieerde SDFmetode
die mees akkurate metode is en dat soortgelyke tendense duidelik was in
al die relevante opvangsgebiede. Die geverifieerde
SDF/waarskynlikheidsverspreiding-verhoudings het, met verwysing na
gemiddeldes, tussen 0.82 en 1.19 gewissel, behalwe in SDF-opvangsgebiede 6
en 21 waar die 5- en 20-jaar herhalingsperiode-vloedpieke onderskeidelik met
41% en 56% oorskat is, wat steeds konserwatief is.
Die sekondêre doelwit van die studie was om ‘n gebruikersvriendelike
“Design Flood Estimation Tool” (DFET) in ‘n Microsoft Office Excel/Visual Basic
for Applications omgewing te ontwikkel om die gebruik en toepaslikheid van die
verskeie ontwerpvloedberamingsmetodes te bepaal.
Die DFET sal ontwerpers voorsien van ‘n sagtewareprogram om alternatiewe
ontwerpvloedberamingsmetodes op streek- of plaaslike skaal te ondersoek en te
evalueer. Die fokus-gebruikersgroep vir die toepassing van die program sal
bestaan uit ingenieurstegnici, ingenieurstegnoloë en ingenieurs werksaam by
raadgewende siviele ingenieurs, nie noodwendig vakkundiges in die veld van
hidrologie nie. Die DFET was gebruik om al die opvangsgebied-,
meteorologiese (reënval) en hidrologiese (waargenome vloeie) data vir die
verskeie ontwerpvloedberamingsmetodes te verwerk.
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Selectivity in NMR and LC-MS Metabolomics : The Importance of Sample Preparation and Separation, and how to Measure Selectivity in LC-MS Metabolomics.Elmsjö, Albert January 2017 (has links)
Until now, most metabolomics protocols have been optimized towards high sample throughput and high metabolite coverage, parameters considered to be highly important for identifying influenced biological pathways and to generate as many potential biomarkers as possible. From an analytical point of view this can be troubling, as neither sample throughput nor the number of signals relates to actual quality of the detected signals/metabolites. However, a method’s selectivity for a specific signal/metabolite is often closely associated to the quality of that signal, yet this is a parameter often neglected in metabolomics. This thesis demonstrates the importance of considering selectivity when developing NMR and LC-MS metabolomics methods, and introduces a novel approach for measuring chromatographic and signal selectivity in LC-MS metabolomics. Selectivity for various sample preparations and HILIC stationary phases was compared. The choice of sample preparation affected the selectivity in both NMR and LC-MS. For the stationary phases, selectivity differences related primarily to retention differences of unwanted matrix components, e.g. inorganic salts or glycerophospholipids. Metabolites co-eluting with these matrix components often showed an incorrect quantitative signal, due to an influenced ionization efficiency and/or adduct formation. A novel approach for measuring selectivity in LC-MS metabolomics has been introduced. By dividing the intensity of each feature (a unique mass at a specific retention time) with the total intensity of the co-eluting features, a ratio representing the combined chromatographic (amount of co-elution) and signal (e.g. in-source fragmentation) selectivity is acquired. The calculated co-feature ratios have successfully been used to compare the selectivity of sample preparations and HILIC stationary phases. In conclusion, standard approaches in metabolomics research might be unwise, as each metabolomics investigation is often unique. The methods used should be adapted for the research question at hand, primarily based on any key metabolites, as well as the type of sample to be analyzed. Increased selectivity, through proper choice of analytical methods, may reduce the risks of matrix-associated effects and thereby reduce the false positive and false negative discovery rate of any metabolomics investigation.
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Aplicação e avaliação de desempenho de método para representação da visão no gerenciamento ágil de projetos em uma empresa de bens de consumo / Implementation and performance evaluation of a method to represent the vision in the agile project management in a consumer goods companyFábio Henrique Trovon de Carvalho 21 October 2011 (has links)
O Gerenciamento Ágil de Projetos (APM) é uma abordagem de desenvolvimento alternativa às práticas tradicionais de gestão de projetos destinada a projetos que envolvam elevado grau de volatilidade de requisitos e fortemente susceptíveis a mudanças, como é o caso de novos produtos inovadores. Um dos principais diferenciais do APM é a substituição da fase de Iniciação do modelo clássico por uma fase denominada Visão. Vários métodos de Visão do produto têm sido propostos, entre eles o PVMM (Product Vision Management Method), que tem como diferencial combinar elementos e práticas dos vários métodos existentes de representação da Visão. Como não há relatos de aplicações do PVMM e de outros métodos de representação em projetos reais, esta foi a hipótese que motivou a elaboração desta pesquisa. Com o propósito de preencher essa lacuna, este trabalho tem por objetivo aplicar o PVMM em projeto real de produto manufaturado e avaliar o desempenho do método do ponto de vista da percepção da equipe de projeto. Como procedimento metodológico foi utilizado o estudo de casos múltiplos em dois projetos de novos produtos da empresa. A análise teve por base dados qualitativos oriundos de relatos da equipe e observações do pesquisador e de dados quantitativos provenientes de instrumentos padronizados de pesquisa. Os dados qualitativos reforçam certas recomendações e hipóteses da literatura que foram utilizadas como base no desenvolvimento do PVMM: a construção de pré-concepções ainda na fase de planejamento do projeto estimula a inovação; a discussão frente-a-frente em quadros estimula a inovação e facilita a discussão; a matriz item-entrega facilita a experimentação e orienta para a prática; a dinâmica e trabalho em equipe orientam e desafiam a equipe em prol da inovação. As análises quantitativas reforçam: orientação para inovação; colaboração; criatividade; elaboração progressiva de requisitos; iteração; agregação de valor para o cliente. Também foram identificadas deficiências principalmente nos requisitos simplicidade e limites do projeto. O trabalho apresenta como proposta de continuidade desenvolver modelos teóricos mais detalhados sobre o conceito de Visão e sua medição; aprimorar o PVMM no que tange a simplicidade dos artefatos criados; utilizar recursos de informática como painéis eletrônicos e softwares de modelagem 3D; aprimorar a matriz item-entrega. / The Agile Project Management (APM) is an alternative development approach to the traditional project management practices. The APM is intended for projects which requirements are elusive, volatile and subject to change such as innovative new products. One of the main differences in the APM approach is the substitution of the Initiation phase from the classical model to a phase named Vision. Several methods aimed to represent the product Vision have been proposed, including the PVMM (Product Vision Management Method). The PVMM is unique since it was developed incorporating a combination of elements and practices gathered from various existing Vision methods. The problem that motivates the development of this research is the lack of papers reporting the application of the PVMM and other methods in real projects. Seeking to fill this gap, this research aims to apply the PVMM in real projects of manufactured products and evaluate the method performance in terms of the project team perception. To conduct the study, it was applied the multiple case study methodological approach in two projects of new products in the company. The analysis was based on qualitative data from reports of the team and researchers\' observations and quantitative data from standardized research instruments. Qualitative data reinforce literature assumptions and recommendations used as the basis for the PVMM development: the construction of pre-conceptions in the planning phase of the project encourages innovation; discussion face-to-face in front of panels stimulates innovation and facilitates communication; the item-entrega matrix is practice-oriented and facilitates experimentation; the dynamics and teamwork oriented and challenge the team for innovation. Quantitative analysis reinforce: guidance for innovation, collaboration, creativity, progressive elaboration of requirements; iteration, adding value to the customer. Were also identified deficiencies in the requirements mainly simplicity and design limits. This research proposes to future studies: develop more detailed theoretical models regarding the Vision conceptualization and evaluation; improve the PVMM in terms of simplicity of the artifacts created; use computer resources such as electronic panels and 3D modeling software; improve the item-entrega matrix.
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Aplicação e avaliação de desempenho de método para representação da visão no gerenciamento ágil de projetos em uma empresa de bens de consumo / Implementation and performance evaluation of a method to represent the vision in the agile project management in a consumer goods companyCarvalho, Fábio Henrique Trovon de 21 October 2011 (has links)
O Gerenciamento Ágil de Projetos (APM) é uma abordagem de desenvolvimento alternativa às práticas tradicionais de gestão de projetos destinada a projetos que envolvam elevado grau de volatilidade de requisitos e fortemente susceptíveis a mudanças, como é o caso de novos produtos inovadores. Um dos principais diferenciais do APM é a substituição da fase de Iniciação do modelo clássico por uma fase denominada Visão. Vários métodos de Visão do produto têm sido propostos, entre eles o PVMM (Product Vision Management Method), que tem como diferencial combinar elementos e práticas dos vários métodos existentes de representação da Visão. Como não há relatos de aplicações do PVMM e de outros métodos de representação em projetos reais, esta foi a hipótese que motivou a elaboração desta pesquisa. Com o propósito de preencher essa lacuna, este trabalho tem por objetivo aplicar o PVMM em projeto real de produto manufaturado e avaliar o desempenho do método do ponto de vista da percepção da equipe de projeto. Como procedimento metodológico foi utilizado o estudo de casos múltiplos em dois projetos de novos produtos da empresa. A análise teve por base dados qualitativos oriundos de relatos da equipe e observações do pesquisador e de dados quantitativos provenientes de instrumentos padronizados de pesquisa. Os dados qualitativos reforçam certas recomendações e hipóteses da literatura que foram utilizadas como base no desenvolvimento do PVMM: a construção de pré-concepções ainda na fase de planejamento do projeto estimula a inovação; a discussão frente-a-frente em quadros estimula a inovação e facilita a discussão; a matriz item-entrega facilita a experimentação e orienta para a prática; a dinâmica e trabalho em equipe orientam e desafiam a equipe em prol da inovação. As análises quantitativas reforçam: orientação para inovação; colaboração; criatividade; elaboração progressiva de requisitos; iteração; agregação de valor para o cliente. Também foram identificadas deficiências principalmente nos requisitos simplicidade e limites do projeto. O trabalho apresenta como proposta de continuidade desenvolver modelos teóricos mais detalhados sobre o conceito de Visão e sua medição; aprimorar o PVMM no que tange a simplicidade dos artefatos criados; utilizar recursos de informática como painéis eletrônicos e softwares de modelagem 3D; aprimorar a matriz item-entrega. / The Agile Project Management (APM) is an alternative development approach to the traditional project management practices. The APM is intended for projects which requirements are elusive, volatile and subject to change such as innovative new products. One of the main differences in the APM approach is the substitution of the Initiation phase from the classical model to a phase named Vision. Several methods aimed to represent the product Vision have been proposed, including the PVMM (Product Vision Management Method). The PVMM is unique since it was developed incorporating a combination of elements and practices gathered from various existing Vision methods. The problem that motivates the development of this research is the lack of papers reporting the application of the PVMM and other methods in real projects. Seeking to fill this gap, this research aims to apply the PVMM in real projects of manufactured products and evaluate the method performance in terms of the project team perception. To conduct the study, it was applied the multiple case study methodological approach in two projects of new products in the company. The analysis was based on qualitative data from reports of the team and researchers\' observations and quantitative data from standardized research instruments. Qualitative data reinforce literature assumptions and recommendations used as the basis for the PVMM development: the construction of pre-conceptions in the planning phase of the project encourages innovation; discussion face-to-face in front of panels stimulates innovation and facilitates communication; the item-entrega matrix is practice-oriented and facilitates experimentation; the dynamics and teamwork oriented and challenge the team for innovation. Quantitative analysis reinforce: guidance for innovation, collaboration, creativity, progressive elaboration of requirements; iteration, adding value to the customer. Were also identified deficiencies in the requirements mainly simplicity and design limits. This research proposes to future studies: develop more detailed theoretical models regarding the Vision conceptualization and evaluation; improve the PVMM in terms of simplicity of the artifacts created; use computer resources such as electronic panels and 3D modeling software; improve the item-entrega matrix.
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