A caracterização de redes e o estudo de sistemas, ambos utilizando grafos, é algo muito usado por várias áreas científicas. Uma das linhas deste estudo é denominada de grafos aleatórios, que por sua vez auxilia na criação de modelos para análise de redes reais. Consideramos um modelo de grafo aleatório não homogêneo criado por Kang, Pachón e Rodríguez (2016), cuja construção é feita a partir da realização do grafo binomial G(n; p). Para este modelo, estudamos argumentos e métodos usados para encontrar resultados sobre o limiar de conectividade, importante propriedade relacionada a existência assintótica de vértices e componentes isolados. Em seguida, constatamos algumas características positivas e negativas a respeito da utilização do grafo para modelar redes reais complexas, onde usamos de simulações computacionais e medidas topológicas. / The characterization of networks and the study of systems, both using graphs, is very used by several scientific areas. One of the lines of this study is called random graphs, which in turn assists in creating models for the analysis of real networks. We consider an inhomogeneous random graph model created by Kang, Pachón e Rodríguez (2016), where its construction is made from the realization of the binomial graph G(n; p). For this model, we studied the arguments and methods used to find results on the connectivity threshold, important property related to asymptotic existence of vertices and isolated components. Then we found some positive and negative characteristics about the use of the graph to model complex real networks, using computer simulations and topological measures.

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.

Submaximal exercise performance is, in part, limited by the accumulation of metabolic byproducts and energy system capacities. Curcumin and the combination of curcumin and fenugreek soluble fiber (CurQfen®) have been shown to increase endogenous antioxidants and metabolic byproduct clearance as well as reduce inflammation and lipid peroxidation, and therefore, may enhance submaximal aerobic thresholds. In addition, there is evidence that the galactomannan component of fenugreek, used to enhance bioavailability of curcumin, may also have potential physiological effects related to the up regulation of free fatty acid oxidation Therefore, the purpose of this study was to examine the effects of curcumin and fenugreek soluble fiber supplementation on the ventilatory threshold (VT), respiratory compensation point (RCP), maximal oxygen consumption (O2 peak), and time to exhaustion (Tlim)derived from a graded exercise test (GXT). Forty-five untrained, college-aged, male (n = 24) and female (n = 21) subjects (mean age ± SD: 21.2 ± 2.5 yr) were randomly assigned to one of three supplementation groups; placebo (PLA, n=13), 500 mg·day-1 CurQfen® (CUR, n=14), or 300 mg·day-1 fenugreek soluble fiber (FEN, n=18). All of the subjects completed a maximal GXT on a cycle ergometer to determine the VT, RCP, O2 peak, and Tlim before (PRE) and after (POST) 28 days of daily supplementation. The VT and RCP were determined from the V-slope method for the ventilation (E)vs. O2 and E vs. CO2, respectively. Separate, one-way ANCOVAs were used to examine the between group differences for adjusted POST VT, RCP, O2 peak, and Tlim values, with the respective PRE test value as the covariate. The adjusted POST VT-O2 for the CUR (mean ± SD= 1.593 ± 0.157 L·min-1) and FEN (1.597 ± 0.157L·min-1) groups were greater than (p= 0.04 and p= 0.03, respectively) the PLA (1.465 ± 0.155L·min-1) group, but the FEN and CUR groups were not different (p = 0.94). The one-way ANCOVAs for RCP (F = 3.177, p = 0.052), O2 peak (F = 0.613, p = 0.547), and Tlim (F = 0.654, p = 0.525) indicated there were no significant differences among groups. These findings suggested that CurQfen® and/or fenugreek soluble fiber may improve submaximal, but not maximal, aerobic performance indices in untrained subjects.

No description available.

Tests to evaluate runners' aerobic capacity aiming to design training programs are often performed on a treadmill, while the training mainly takes place on over-ground surfaces. Studies have shown that different degrees of inclination on treadmills can compensate for the differences in heart rate (HR) response between running on treadmills and over-ground surfaces. The purpose of the study was to test whether the blood lactate concentration (BLC) differs between over-ground running and treadmill running at matched HR, and if so; can inclination of the treadmill be adjusted to generate equal BLC at matched HR? Eight male elite runners performed three incremental running tests where HR and BLC were measured; on a flat treadmill at six running velocities, on a running track at six velocities equal to the HR at test one, and on a treadmill at a fixed HR on different inclines (0°, 0.3°, 0.6°, 0.9°, 1.1° and 1.5°). The results revealed a non-significant trend indicating that over-ground running yields higher BLC at matched HR than treadmill running, and that 0.3° incline on treadmill correlated best with over- ground running. This study demonstrates a clear tendency of higher BLC at a given HR when running on an over-ground surface in comparison to running on a treadmill. Furthermore, a 0.3° incline on a treadmill is suggested to compensate for the difference in BLC at matched HR, between running on a treadmill and on an over-ground surface. However, more research with a larger sample size is needed to conclude and generalize the results.

Field and laboratory experiments were conducted to elucidate various factors influencing the temperature-dependent larval eclosion of winter moth, Operophtera brumata L, in New England. We found no difference in duration of the embryonic stage of eggs reared from larvae collected in Massachusetts (MA) and on Vancouver Island, British Columbia (BC), where winter temperatures are rarely below freezing. The number of growing degree days (GDD) required for larval eclosion declined with the number of days chilled in the laboratory and number of days below freezing in the field, confirming the findings of previous studies. Thus, eggs hatched with fewer GDD, when the spring came later than usual. Date of oviposition had no effect on date of hatch. Eggs laid by naturally occurring (feral) females hatched sooner with lower GDD than eggs from laboratory-reared females from MA and BC held on the same trees over the winter. South-facing eggs on the stems of trees hatched on average 1.6 days sooner than north-facing eggs. Growing degree days calculated from bi-hourly measures of temperature were 15% greater than GDD estimates based on the average of daily maximum and minimum temperatures, as used by many GDD estimates made for online sources. Over two years, the mean GDD in ⁰C for hatch of feral eggs based on bihourly temperature measurements, a 1 Jan start date and a 3.9⁰C developmental threshold was 176.53 ± 6.35SE

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.

Sleep Convention Logic (SCL) is an emerging ultra-low power Quasi-Delay Insensitive (QDI) asynchronous design paradigm with enormous potential for industrial applications. Design validation is a critical concern before commercialization. Unlike other QDI paradigms, such as NULL Convention Logic (NCL) and Pre-Charge Half Buffers (PCHB), there exists no formal verification methods for SCL. In this thesis, a unified formal verification scheme for combinational as well as sequential SCL circuits is proposed based on equivalence checking, which verifies both safety and liveness. The method is demonstrated using several multipliers, MACs, and ISCAS benchmarks.

For many years, speech recognition threshold (SRT) testing has been used as an indicator of audiologic health. However, with changing methods and technology, test-retest reliability has not been reviewed extensively with newer digitally recorded spondaic words which meet a published criterion of listener familiarity. This study examined the test-retest reliability of 33 high frequency usage and psychometrically equated spondaic words. The American Speech-Language-Hearing Association recommended method (2-dB decrements) was used to measure the left and right SRT of 40 participants using both male and female talker recordings. For each participant, four SRTs were found during the test condition and four SRTs were found during the retest condition. All of the SRT scores were analyzed and the averaged SRT values found using a male talker recording resulted in an average retest SRT to be 1.4 dB better than the average test SRT. The averaged SRT values found using a female talker recording resulted in an averaged retest SRT to be 1.2 dB better than the averaged test SRT. The SRT scores also showed high validity when compared to each participant's pure tone average (PTA). This study additionally found no significant interaction in using a male versus a female talker when using digitally recorded and psychometrically equated spondaic words.

Recent advances in the field of audiology have indicated that there has been a growing concern regarding the potential damage to the hearing mechanism induced by recreational noise exposure from personal music devices (PMD). Regular PMD use may have a long-term damaging effect on the outer- and inner hair cells of the cochlea which may result in a progressive hearing loss. As PMDs have advanced to a stage where the memory of the devices are able to contain hours of listening content, the environments where these devices are being used are rapidly expanding. Many young adults tend to use their PMDs whilst exercising. Exercise in itself induces physiological and metabolic changes such as increased blood flow and oxygen levels within the structures of the cochlea. The purpose of this study was to determine the differential impact and short-term effects of simultaneous cardiovascular workout and personal music device (PMD) use on the otoacoustic emissions of young adults. Seven female and five male subjects completed three testing conditions: (i) one hour exposure to PMD use in isolation, (ii) one hour exposure to cardiovascular workout in isolation, and (iii) one hour simultaneous exposure to PMD use and cardiovascular workout. Distortion product otoacoustic emissions (DPOAEs) were conducted prior to, as well as directly following each testing condition, as primary indicator of cochlear responses emitted through a preset stimulus frequency sequence measuring the 2f₁ - f₂ (75 – 70 dB SPL) and constructing a plot of DPOAE levels as a function of frequency. While each of the testing conditions on its own did not result in statistically significant changes of the DPOAE response, a highly significant different profile in the DPOAE response level increase/decrease for the higher frequencies (6-8 kHz) was obtained when comparing the different sessions to each other. Where exposure to cardiovascular workout showed a clear trend of an increased DPOAE response level between the pre-exposure and post-exposure testing from 2 kHz to 8 kHz with a maximum increase at 6 kHz, both the music only condition and the combined condition where the cardiovascular workout was combined with music resulted in a significant different profile. During combined exposure a clear trend of decreased DPOAE response amplitudes between the pre-exposure and post-exposure testing were seen for the higher frequencies. These findings may support the notion of a clear effect of cardiovascular workout on the otoacoustic emissions at higher test frequencies, measured by DPOAEs when performed with and without music exposure. / Dissertation (MLOG)--University of Pretoria, 2014. / tm2015 / Speech-Language Pathology and Audiology / MLOG / Unrestricted