O objetivo do presente estudo foi verificar a possibilidade de identificação dos dois limiares metabólicos pelo comportamento da VFC. Para isso, 22 voluntários do gênero masculino [74,5 + 7,99kg, 177,0 + 8cm, 23,86 + 1,69 (índice de massa corporal) e 9,10 % de gordura], habituados à prática do ciclismo, realizaram teste ergométrico em bicicleta estacionária com carga inicial de 120W e incrementos de 30W a cada 3min, até a exaustão. Durante todo o teste foram feitos os registros da freqüência cardíaca (FC) e de sua variabilidade (VFC) e ao final de cada carga foram coletados 25µL de sangue para análise da concentração sangüínea de lactato. Aplicou-se um modelo matemático que ajustou a curva da VFC em três retas e o primeiro e segundo limiar de VFC foram identificados nas intersecções entre as retas. Para identificação do primeiro e segundo limiar de lactato, considerou-se as concentrações fixas de 2,0 e 3,5mM, respectivamente. A análise de variância para medidas repetidas indicou não haver diferenças significativas nas cargas em que os limiares de VFC e de lactato foram encontrados, mostrando que a metodologia proposta pode ser promissora. Entretanto a falta de correlação entre as variáveis indica que novos estudos necessitam ser realizados para confirmação desta possibilidade. / The purpose of this study was to verify the possibility of metabolic thresholds identifications through HRV. For that, 22 male volunteers [74,5 + 7,99kg, 177,0 + 8cm, 23,86 + 1,69 (body mass index) e 9,10 % fat], familiarized to cyclism practice, realized a cycloergometer test with initial load of 120W and 30W increases every 3min., until exhaustion. During all test, it was registered heart rate (HR) and its variability (HRV) and, at the end of each load, it was collected 25mL blood for lactate concentration analysis. It was applied a mathematical model to adjust HRV curve in three straight lines and first and second HRV thresholds were identified in intersections among the lines. For the identification of first and second lactate thresholds, it was considered 2,0 and 3,5mM fixed concentrations, respectively. Variance analysis for repeated measures indicated that there were no significant differences between loads in which HRV and lactate thresholds were found, showing that purposed methodology can be promissor. However, the lack of correlation between variables indicate that new studies must be made to confirm that possibility.

abstract: Multi-material fabrication allows for the creation of individual parts composed of several materials with distinct properties, providing opportunities for integrating mechanisms into monolithic components. Components produced in this manner will have material boundaries which may be points of failure. However, the unique capabilities of multi-material fabrication allow for the use of graded material transitions at these boundaries to mitigate the impact of abrupt material property changes. The goal of this work is to identify methods of creating graded material transitions that can improve the ultimate tensile strength of a multi-material component while maintaining other model properties. Particular focus is given towards transitions that can be produced using low cost manufacturing equipment. This work presents a series of methods for creating graded material transitions which include previously established transition types as well as several novel techniques. Test samples of each transition type were produced using additive manufacturing and their performance was measured. It is shown that some types of transitions can increase the ultimate strength of a part, while others may introduce new stress concentrations that reduce performance. This work then presents a method for adjusting the elastic modulus of a component to which graded material transitions have been added to allow the original design properties to be met. / Dissertation/Thesis / Supplementary code from appendices / Masters Thesis Engineering 2020

Thesis (M.Sc. ( Agricultural Economics)) --University of Limpopo, 2019 / The demand for animal products is projected to increase progressively due to extensive urbanization, rapid growth of human population and income dynamics. However, the evolution of food demand is strictly linked to the change in consumer preferences. Consumers around the world are progressively becoming more concerned and aware about food standards, quality and safety issues. The purpose of this study was to determine consumers’ preference regarding safe and quality beef and WTP for graded beef in Polokwane municipality. The research surveyed 150 consumers using a structured questionnaire to collect data on consumer characteristics and responses to different bid levels for graded beef. Analytical methods were descriptive statistics, Likert scales, contingent valuation method to evaluate respondents’ mean WTP for graded beef and logit model to determine the dependence of WTP on socioeconomic factors. Results showed that consumers prefer their beef tender, with less fat and bones and labelled with price, grade/class, size or quantity of the product and lastly quality inspection or certification indicator. Over half of the respondents (53%) were aware of grading or classification systems. The results further revealed that most respondents are willing to pay an increase of 16.04 % over the current price for beef. This could be an opportunity for investments in beef label industry. Consumer characteristics including age, income, gender and household size significantly influenced WTP for graded beef in Polokwane Municipality. Marketing strategies considered by beef product investors should target young, female and wealthier consumers. Grading with respect to quality attributes would make beef sales at differentiated prices possible. This will eventually enhance sales volume and returns for all stakeholders along the value chain / National Research Fund

No description available.

Background: The end-product of glycolysis is lactate, which is subsequently oxidised to produce more energy. With increasing intensity, the rate of lactate production exceeds the capacity to eliminate lactate, leading to an exponential accumulation of blood lactate. Clinicians use incremental graded exercise tests to induce this blood lactate curve. Two distinct thresholds can then be determined from the curve, of which the second threshold is highly correlated with competitive endurance performance. The exact threshold intensities depend on the threshold concept used as well as on variations in the test protocol. Aim: To evaluate how the Finnish lactate threshold concept is affected by using stage durations of 5 minutes instead of the recommended 3, and to determine how this affects the maximal oxygen uptake. Methods: Seven well-trained adults were recruited to perform two separate incremental graded exercise tests with 3- and 5-minute stages, respectively. Lactate thresholds were determined directly by blood lactate measurements and according to the instructions of the Finnish Society of Sport Sciences. Breath-by-breath gas exchange was measured throughout the tests.  Results: No significant differences occurred at the first lactate threshold. At the second lactate threshold, heart rate, oxygen uptake and blood lactate remained unchanged, while speed dropped (-0.81 ±0.81 km/h; p=0.037) when comparing the 5-minute protocol with the 3-minute protocol. Both protocols resulted in similar peak oxygen uptakes, while speed at peak oxygen uptake decreased (-1.07 ±0.89 km/h; p=0.015) for the 5-minute protocol. Conclusion: This study showed that the chosen stage duration does not affect the blood lactate at the first or second lactate threshold, while a longer stage duration does affect the work intensity corresponding to the second lactate threshold of the Finnish lactate threshold concept. As the work intensity at LT2 is often used to prescribe endurance training and to predict competitive endurance performance, these findings can be of interest to the endurance testing community. It enables an extended understanding when designing test protocols and when analysing the results of a lactate threshold test. This might in turn contribute to more accurate exercise intensity prescriptions and thereby faster development among endurance athletes. Further research with more subjects as well as research into the validity of the Finnish lactate threshold concept is recommended. / Bakgrund: Vid glykolys bildas laktat som biprodukt som sedan oxideras för att producera mera energi. Vid högre träningsintensitet produceras mer laktat i kroppen än kroppen hinner oxidera och därmed börjar laktat ackumuleras i blodet. Kliniskt används inkrementella träningstester för att framkalla en blodlaktatkurva. Vanligtvis bestäms två distinkta trösklar ur kurvan, av vilka den andra laktattröskeln är starkt korrelerad med uthållighetsprestation i tävlingssammanhang. Den exakta träningsintensiteten vid trösklarna beror på metoden som använts för att bestämma trösklarna ur blodlaktatkurvan samt variationer i testprotokollet. Syfte: Att bedöma hur den finska metoden för att bestämma laktattrösklarna påverkas då ett testprotokoll med 5-minutersnivåer används istället för de rekommenderade 3-minutersnivåerna, samt att bedöma hur detta påverkar den maximala syreupptagningsförmågan. Metoder: Sju vältränade vuxna utförde två separata inkrementella träningstester, med 3-minuters- respektive 5-minutersnivåer. Laktattrösklarna bestämdes med hjälp av blodlaktatmätningar och enligt instruktionerna av the Finnish Society of Sport Sciences. Försökspersonernas gasutbyte loggades under hela testernas gång.  Resultat: Inga signifikanta skillnader fanns vid första laktattröskeln. Vid den andra laktattröskeln var puls, syreupptagning och laktatnivå samma för båda protokollen, medan löphastigheten var lägre (-0.81 ±0.81 km/h; p=0.037) för 5-minutersprotokollet jämfört med 3-minutersprotokollet. Båda protokollen resulterade i liknande maximalt syreupptag, men löphastigheten vid maximalt syreupptag var lägre (-1.07 ±0.89 km/h; p=0.015) vid 5-minutersprotokollet.  Slutsatser: Studien visade att nivåernas varaktighet inte påverkade laktatvärdet vid första eller andra laktattröskeln, men att en längre nivålängd påverkar arbetsintensiteten vid den andra laktattröskeln då den finska metoden för att bestämma trösklarna används. Eftersom arbetsintensiteten vid den andra laktattröskeln ofta används för att förutse uthållighetsprestation i tävlingssammanhang samt för att ordinera arbetsintensitet för uthållighetsträning kan studien bidra med en värdefull förståelse för individer som jobbar med uthållighetstester. De kan utnyttja denna förståelse både då de utvecklar testprotokoll och då de analyserar resultat från tröskeltester. I längden kan detta leda till noggrannare ordineringar vad gäller arbetsintensitet och därmed en snabbare utveckling bland uthållighetsidrottare. Ytterligare forskning med fler försökspersoner samt forskning för att validera den finska metoden för att bestämma laktattrösklar behövs.

This study investigated the effects of ungraded running and graded walking as modalities of HIIT on enjoyment, perceived exertion, and affect. 29 healthy males and females (aged 23.3 ± 5.1) volunteered to participate in the study. Participants completed six visits to the laboratory: the first was a medical screening to ensure safety of the participants. For the second and third visits, participants completed two maximal treadmill exercise tests, one running and one walking. On the fourth visit, the speed needed for the run HIIT (running speed: 6.9 ± 1.2mph) and the grade needed for the walk HIIT (walking speed: 3.3 ± 0.3mph, walking grade: 17.2 ± 3.1%) experimental trials were confirmed. During the last two visits, participants completed both of the two (run HIIT and walk HIIT) randomized and counterbalanced experimental trials. Affective valence was measured at baseline and post-exercise. The single-item Feeling Scale (FS) and the Borg 6-20 RPE scale (both overall exertion and legs-only exertion) were used to measure in-task ratings of affect and exertion. The Physical Activity Enjoyment Scale (PACES) and FS were used to measure post-exercise ratings of enjoyment and affect. Results revealed a main effect for condition for post-exercise enjoyment (p < 0.001), with the run HIIT being more enjoyable. A main effect was also found for time for both overall exertion and legs-only exertion (p < 0.001 for both interactions), with the walk HIIT producing higher exertion ratings. There was a main effect for condition of legs-only exertion (p = 0.004), again walk HIIT produced higher exertion ratings. Lastly, there was a main effect when comparing 20% and 100% of total time in the run HIIT and the walk HIIT conditions, for both overall exertion and legs-only exertion (p < 0.001 for all interactions). This shows that exertion increased over time for both conditions. Exertion ratings, both overall and legs-only tended to be highest during the run HIIT condition when compared to the walk HIIT. The opposite was true for affective valence, the ratings were higher in the run HIIT condition than the walk HIIT. In conclusion, the perceptual responses in this study, which represent enjoyment, exertion and affective valence, were generally more favorable during the run HIIT condition. These results support previous findings to suggest that doing a running protocol is a well-tolerated and favorable modality for HIIT exercise.

Reading English literature can help learners of English as a foreign language (EFL) to develop their reading ability as well as other language skills. Reading can also have other benefits for EFL students such as learning about the target language’s culture or learn about an English variety in written form. This present study investigates what types of literature are used in Swedish upper secondary school, the EFL teachers’ attitudes towards short stories compared to simplified novels/graded readers and their preferred assessment methods associated with literature teaching. The majority of the teachers that took part in this survey have a positive attitude towards short stories and use them in their EFL classes. The results also show that after the students have completed reading a short story, most of the teachers that participated in this survey preferred to combine examination methods such as a group discussion with a written test. The title of this paper comes from one of the informants’ comments when asked if she would rather use a short story or a graded reader in her English class. This informant had used graded readers in her English language classroom, but she and everyone that took part in this survey chose short stories over graded readers.

El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado. / In this research, an improved first order formulation is presented to study the critical buckling load in functionally graded beams. The formulation has five independent variables in comparison with the Timoshenko theory that has three. The Trefftz criterion is utilized with incremental and fundamental states to define the stability analysis. Virtual work statements are derived for the finite element model where the field variables are interpolated by Lagrange polynomials. The numerical results are compared and verified with other formulations found in literature. Parametric studies are also carried out for buckling behavior due to different slenderness ratios, power-law indices and boundary conditions. Applications of the model to functionally graded materials show the validity of the present approach.

Simplicial complexes are mathematical objects whose importance stretches from topology to commutative algebra and combinatorics. In this thesis we focus on the family of balanced simplicial complexes. A d-dimensional simplicial complex is balanced if its 1-skeleton can be properly (d+1)-colored, as in the classical graph theoretic sense. Equivalently, a d-dimensional complex is balanced iff it admits a non-degenerate simplicial projection to the d-simplex. We present results on these complexes from a number of different points of view. After two introductory chapters, we exhibit in chapter 3 an infinite family of balanced counterexamples to Stanley's partitionability conjecture. These complexes, which are in addition constructible, answer a question of Duval et al. in the negative. Next we shift to combinatorial topology, and study cross-flips, i.e., local moves on balanced manifolds introduced by Izmestiev, Klee and Novik, which preserve both the coloring and the topological type. In chapter 4 we provide an explicit description and enumeration of an interesting subset of these moves and use it to prove a Pachner-type theorem. Indeed, we show that any two balanced combinatorial manifolds with boundary which are PL-homeomorphic can be transformed one into the other by a sequence of shellings and inverse shellings which preserve both the coloring and the topological type at each step. This solves a problem proposed by Izmestiev, Klee and Novik. Chapter 5 is devoted to the study of certain algebraic invariants of simplicial complexes in the balanced case. Here upper bounds for the graded Betti numbers of the Stanley-Reisner ring of balanced simplicial complexes are investigated in several level of generalities, and we show that they are sharper than in the general case. First, we employ Hochster formula to obtain inequalities for the case of arbitrary balanced complexes. Next, we focus on the balanced Cohen-Macaulay case and we obtain two upper bounds via two different strategies. Using similar ideas we also bound the Betti numbers in the linear strand of balanced normal d-pseudomanifolds, for d>2. Finally, we explicitly compute graded Betti numbers of the class of stacked cross-polytopal spheres, and conjecture that they provide a sharp upper bound for those of all balanced pseudomanifolds with the same dimension and number of vertices. In the last chapter, we implement cross-flips on balanced surfaces and 3-manifolds, and use this computer program to search for balanced manifolds on few vertices, possibly vertex-minimal. Reducing the barycentric subdivision of vertex minimal triangulations, we find a long list of balanced triangulations of interesting spaces on few vertices. Among those stand out a balanced vertex-minimal triangulation of the dunce hat (11-vertices) and of the 2- and 3-dimensional real projective space (9 and 16 vertices respectively). Using obstructions from knot theory and a careful choice of flips we find a balanced non-shellable 3-sphere and a balanced shellable non-vertex-decomposable 3-sphere on 28 and 22 vertices respectively. These are the smallest instances known in the literature.

Indiana University-Purdue University Indianapolis (IUPUI) / Thin-walled structures find wide applications in the automotive industry as energy absorption devices. A great deal of research has been conducted to design thin-walled structures, where the main objective is to reduce peak crushing forces and increase energy absorption capacity. With the advancement of computers and mathematics, it has been possible to develop 2D patterns which when folded turn into complex 3D structures. This technology can be used to develop patterns for getting structures with desired properties. In this study, square origami tubes with folding pattern (Yoshimura pattern) is designed and studied extensively using numerical analysis. An accurate Finite Element Model (FEM) is developed to conduct the numerical analysis. A parametric study was conducted to study the influence of geometric parameters on the mechanical properties like peak crushing force, mean crushing force, load uniformity and maximum intrusion, when subjected to dynamic loading. The results from this analysis are studied and various conclusions are drawn. It is found that, when the tube is folded with the pattern having specific dimensions, the performance is enhanced significantly, with predictable and stable collapse. It is also found that the stiffness of the module varies with geometrical parameters. With a proper study it is possible to develop origami structures with functionally graded stiffness, the performance of which can be tuned as per requirement, hence, showing promising capabilities as an energy absorption device where progressive collapse from near to end impact end is desired.