207,474 research outputs found
Gluten-free bread. I. Development of a gluten-free sourdough
No full textAlthough the food industry has risen to the formulation challenges associated with removing gluten from the dough, and a number of gluten-free (GF) products are now commercially available on the market, many GF breads formulations are frequently based on pure starches and still result in low technological and nutritional quality, dry crumb and poor overall mouthfeel and flavor of the final breads (Mariotti et al., 2013). Sourdough is the foremost fermentation used for baking purposes and it has been proven to be ideal for improving the texture, palatability, aroma, shelf-life and nutritional value of wheat and rye breads. Even if these effects have been extensively studied and well described for the traditional baking, little is known about the role of sourdough in GF baking (Moroni et al., 2009). In the last years, however, some studies evidenced various improvements in GF bread volume, crumb structure, flavor and shelf-life (mold-free) when a sourdough was used as leavening agent. All these benefits are mainly due to the starter cultures used and to the organic acids and aminoacids released during the leavening process. In this contest, the aim of this study was the set up of a GF sourdough from selected bacteria and yeasts isolated from a wheat-based sourdough. In particular, the microorganisms of interest (Candida humilis and Lactobacillus sanfranciscensis) were isolated from a traditional sourdough used for the production of Panettone (a well-known Italian sweet baked product). The isolated strains were inoculated (105 CFU/g C. humilis, 107 CFU/g Lb. sanfranciscensis) into a GF matrix, containing corn starch, rice flour, pea isolate, hydrocolloids and fiber as main ingredients (the optimized recipe comes from previous studies). The mass was fermented at 25°C for 24h. The GF inoculum was then added (10% integration level) to another GF matrix, very similar to the previous one, to produce the GF sourdough. This starter (called ‘mother dough’) was constantly and continuously propagated (10 refreshments covering a period of 30 days), and its properties were regularly monitored, particularly in terms of number and type of microorganisms, dough consistency, dough titratable acidity and capability to produce and retain CO2 (rheofermentographic test). During the fermentation process, the pH was continuously recorded and the leavening phase was considered complete when the values were equal to 3.8-4.0. A stable association between microorganisms, measured both in terms of microbiological population (e.g. number of microorganisms, type of microorganisms, ratio between yeasts and bacteria) and technological properties (e.g. amount of water added to the dough to reach the desired consistency, time required to obtain the full sourdough, CO2 production and retention volumes, titratable acidity etc.) of the GF sourdough was obtained just after the second refreshment; all these properties remained constant and satisfactory from here onwards, thus attesting that a GF sourdough had effectively been developed. Only at this point some bread-making trials were performed, in order to compare the properties and quality of GF breads obtained using the developed GF-sourdough, the compressed yeast (Saccharomyces cerevisiae) or their mixture, as leavening agents (see: Gluten-free bread. II. Compressed yeast versus sourdough)
Free C+ actions on affine threefolds
No full textWe study algebraic actions of the additive group C+ on an affine threefold X and prove a smoothness property for the quotient morphism X -< X//C+. Then, following Shulim Kaliman, we give a proof of the conjecture that every free C+ action on affine 3-space C^3 is a translation
Impacts of the COVID-19 pandemic on the development of cognitive and motor skills of Grade R learners
No full textDissertation (M.Ed.(Early Childhood Development and Learning))--University of the Free State, 2024The main aim of this study was to determine the impact of the COVID-19 pandemic on the development of cognitive and motor skills of Grade R learners in the Motheo district of the Free State province, South Africa. To implement this research, four specific objectives, four research questions, and four null hypotheses, were formulated to guide the study. The study adopted an Ex-post-facto research design. The study used a quantitative research approach with a sample size of 160 respondents which comprised of 150 Grade R learners and 10 Grade R teachers. The instrument for data collection was a questionnaire developed by the researcher on cognitive and motor skill development. The instrument was validated by experts in measurement and evaluation, and early childhood education. The reliability of the instrument was ascertained using Cronbach’s Alpha with coefficients of 0.82, 0.87, 0.79 and 0.88 for clusters A, B, C and D respectively. Mean and standard deviation were used to answer the research questions that guided the study, while an independent sample t-test was used to test the null hypotheses at 0.05 level of significance. The findings of the study showed that the cognitive and motor skills development of Grade R learners were above average. It was also found that the COVID-19 pandemic had a negative impact on the cognitive and motor skills development of Grade R learners. It was concluded that the COVID-19 pandemic had a negative impact on the cognitive and motor skills development of Grade R learners in the Motheo district. Based on the results of the study, it is recommended, among others, that efforts should be made by the school management, teachers, and parents, to promote activities that will enhance the cognitive and motor skills development of Grade R learners. This can be achieved by engaging the Grade R learners in activities that will promote and develop their cognitive and motor skills
Exploring the influence of neurofeedback training on Grade R learners’ concentration levels for school readiness
No full textThesis (Ph.D.(Psychology of Education))--University of the Free State, 2022The premise of this study is to explore the influence of neurofeedback training on Grade R learners’ concentration levels for school readiness. In order to understand the complexity of this study, it is important to note the past inequalities and the effect of it on children, specifically on their concentration levels within the classroom and the changes it brought to where the education system is today. This background gave way to the purpose of this study to determine the influence of neurofeedback training on Grade R learners’ concentration levels for school readiness, as well as to determine the experience teachers have with learners’ concentration levels in school. Furthermore, I want to establish how teachers perceive neurofeedback and the implementation thereof. This will indicate if it would be possible to implement neurofeedback training into the South African educational system and to determine the support teachers need to do so. A mixed method approach was followed, whereby the research adopts an embedded convergent research design, whereby qualitative and quantitative research data are embedded in a larger design. The sampling utilizes a simple multi-stage purposeful random sample design. The first stage is a random selection and the following stage is purposive selection of participants (Onwuegbuzie & Collins, 2007). The population involved all Primary Schools from the Motheo District, in the Free State Province, South Africa, who were willing to take part in this study. The data gathered from the questionnaires was analysed by a statistician with the program called Python to the point where the data could be represented in graph form. The data from the document analysis was done, were a six (6) page report, received from the qualified occupational therapist. The data from the focus group interview was also interpreted in conjunction with the data found from the document analysis to clarify, support and strengthen the results found. Literature was also collected with regard to theories and aspects of concentration, child development, as well as neurofeedback, and the necessary inferences and conclusions drawn. Findings from the study were significant and positive in terms of the possible implementation of Brain Gain Neurofeedback training into the South African school curriculum as well as the need, almost desperation, that were identified that exist among teachers
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
The creative photographic image
No full textThesisThe author ha.s chosen to explore the po ss ibilit y that the
creative talent exhibited by an artist's perceptive powers can be
equalled
effects.
by the photographer through subtle use of special
To this e nd the author has explo l'ed a pl'obiem encountered
particularly in 1990's photography which has resulted ill a mass
of high quality photographs taken by large numbers of amateurs
world- wide, who are u si ng sophisticated moderrl camet's technology
as a recording tool without achieving that element of creativity
which captul'es DU I' attention and communicates with our inmost
beings.
The authol' ha s used his own photogl'aphic work and t.ha t of
contempor"ary photogr'aphers in his field of s tudy, to su bstantiate
the claim that thl'ough use of subtle special effects in a ,'ariety
of topics, the photograph can be used a s imaginatively and
c reative ly a s an i mage pI'oduced by a competent artist o r' painter.
This observati.on could have important implication s for an
industry which throug}l co mput er' tec}lnology PI'oposes t o go beyond
the technical re strictions o f the painter whil s t main tai ning that
p rofession's cl"eative flexibility. These spec ial effects should, i n the Buttlo r"s opinion be u sed not
as an e nd to th e mselves, bu t as a mea n s o f transfol~ min g the
of ten c linical med ium of pho tography into a creative tool li lni te d
only by th e photographer's imaginative power's
A system of degenerate parabolic nonlinear PDE's: a new free boundary problem
No full textWe prove existence of solutions of a new free boundary problem described by a system of degenerate parabolic equations. The problem arises in petroleum engineering and concerns fluid flows in diatomite rocks. The unknown functions represent the pressure of the fluid and a damage parameter of the porous rock. These quantities are not necessarily continuous on the free boundary, which considerably complicates the mathematical analysis
Independent sets of maximum weight in apple-free graphs
No full textWe present the first polynomial-time algorithm to solve the maximum weight independent set problem for apple-free graphs, which is a common generalization of several important classes where the problem can be solved efficiently, such as claw-free graphs, chordal graphs, and cographs. Our solution is based on a combination of two algorithmic techniques (modular decomposition and decomposition by clique separators) and a deep combinatorial analysis of the structure of apple-free graphs. Our algorithm is robust in the sense that it does not require the input graph G to be apple-free; the algorithm either finds an independent set of maximum weight in G or reports that G is not apple-free
Modelling free gas overpressure in peat layers
No full textThe paper assesses fully coupled hydro-mechanical numerical approaches developed for unsaturated soils to model the effect of free gas overpressure on the response of peat layers. A simple linear model is used for the soil skeleton, however, the global response is non-linear due to changes over time of the compressibility of the solid skeleton over the compressibility of the fluid, and solubility of gas in water. The overpressure generated in foundation peat layers by barometric pressure oscillations is modelled, and the results are compared to literature data. The development of pore overpressure upon unloading is analysed as a function of the soil skeleton compressibility, and the consequences on the average stress acting on the soil skeleton are discussed
- …
