Kreativitet är en av de mest eftertraktade och värderade mänskliga förmågorna, särskilt inom konst, teknologi och vetenskap. Vetenskapliga studier av kreativitet har visat svaga samband med personlighet och intelligens, egenskaper som annars är starka prediktorer för prestation. Kreativitet är dock rimligtvis kopplad till någon typ av prestationsaspekt av hjärnans funktion. En sådan aspekt är förmågan till timing, dvs beteenden och bedömningar som har med tid och tidsprecision att göra. Syftet med denna studie var att undersöka om timing är associerat med kreativitet, kontrollerat för personlighet och intelligens. Guilford’s Alternative Uses Task användes för att mäta kreativ originalitet och Inventory of Creative Activities and Achievements för att mäta kreativ effektivitet på 66 personer mellan 20-40 år som även testades för timingförmåga, psykometrisk intelligens och personlighet (the Big Five). Trots en signifikant korrelation mellan kreativ effektivitet och timing visade en multipel regression att personlighetsdimensionen öppenhet (O) förklarade mest varians (R2 = 13%) varvid timing utgjorde 2% (icke-signifikant) av den totalt drygt 30% förklarade variansen. Kreativ originalitet uppvisade inga signifikanta korrelationer med någon annan variabel. Ytterligare forskning kring tänkbara egenskaper som skulle kunna bidra med förståelse för kreativitet är önskvärd. / Creativity is one of the most desired and valued human abilities, particularly within art, technology and science. Scientific studies of creativity exhibit weak associations with personality as well as intelligence, traits that are otherwise strong predictors for achievement. Creativity is, however, reasonably linked to some performance aspect of brains function. One such aspect is timing ability, behaviours and assessments that include time and temporal precision. The purpose of this study was to assess whether creativity is associated with creativity, controlling for intelligence and personality. Guilford’s Alternative Uses Task was used for measuring creative originality and Inventory of Creative Activities and Achievements was used for measuring creative effectiveness for 66 participants between 20 and 40 years of age, who were also tested for timing ability, psychometric intelligence, and personality (the Big Five). While there was a significant correlation between creative effectiveness and timing, multiple regression showed that the personality dimension openness (O) explained most of the variance (R2 = 13%), wherewith timing accounted for 2% of about 30% explained variance for all other variables. Creative originality exhibited no significant correlations with any other variable. Further research on traits that may influence creativity is desirable.

ITC/USA 2009 Conference Proceedings / The Forty-Fifth Annual International Telemetering Conference and Technical Exhibition / October 26-29, 2009 / Riviera Hotel & Convention Center, Las Vegas, Nevada / Data-aided symbol synchronization for bursty communications utilizes a predetermined modulation sequence, i.e., a preamble, preceding the payload. For effective symbol synchronization, this preamble must be designed in accordance with the modulation format. In this paper, we analyze preambles for shaped offset quadrature phase-shift keying (SOQPSK) waveforms. We compare the performance of several preambles by deriving the Cram´er-Rao bound (CRB), and identify a desirable one for the Telemetry Group variant of SOQPSK. We also demonstrate, via simulation, that the maximum likelihood estimator with this preamble approaches the CRB at moderate signal-to-noise ratio.

Thesis (MSc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Hops is a small, but important agricultural commodity in South Africa. The hop cones contain secondary metabolites responsible for the flavour, aroma and bitterness in beer. The George and Waboomskraal area are the best suited for growing hops due to climate and geographical location. The optimum latitude for hops growing is 45° - 54° north and south of the equator, while these areas are at 34° S. International hop varieties are not adapted to the South African climate. Winters are too warm and summer days too short, thus all the varieties grown in South Africa have been bred for these specific conditions. The Hop breeding and research program strives to develop internationally competitive varieties with higher yields, desirable brewing characteristics, reducing input costs and increased productivity. To evaluate the current agricultural practices and to determine whether some of these practices negatively affect the plant health and yield, a study was conducted to investigate the effect of the time of stripping. Stripping refers to the practice of removing basal growth of the lower laterals and untrained bines. The study was done in two different microclimates, namely George and Waboomskraal. The aim was to determine the effect of the time of stripping on the vegetative growth, light interception, biomass, soft resins (alpha and beta acids), yield, rootstock weights and carbohydrate concentrations. The effect of stripping was also evaluated on different planting systems and plant maturity, namely Tram lines and conventional planting and 3 years old versus 5 year old plants. The effect of early stripping in terms of dry weight on mature plants is considerably less than the effect on younger plants. Young plants delivered lower dry weights, but accumulated higher carbohydrate reserves in the early stripping treatment. On young plants early stripping showed a significant difference favouring yield on tramlines. There is a general trend across all sites of higher crop efficiencies in the early stripped treatments. Growers could significantly increase yields without negatively affecting the quality (alpha and beta acids) by applying early stripping, especially in the George area. The effect of early stripping becomes more apparent in consecutive years as the time of defoliation affects foliage, carbohydrate concentration, canopy microclimate and light interception resulting in increased yields, especially on tramlines. From this study it can be concluded that early stripping appeared to have an influence on the dry root weight, carbohydrate concentration, light interception, crop efficiencies, yield and biomass. This practice is not only environmentally friendly by using less herbicide, it also delivers an economic gain. The effect of the time of stripping in consecutive years and different varieties deserves further study. / AFRIKAANSE OPSOMMING: Hops is 'n klein, maar belangrike landbou kommoditeit in Suid-Afrika. Die hopkeëls bevat sekondêre metaboliete wat verantwoordelik is vir die smaak, aroma en bitterheid van bier. Die George en Waboomskraal gebied is die beste geskik vir die kweek van hops, a.g.v. die klimaat en geografiese ligging. Die optimum breedtegraad vir hops verbouing is tussen 45° - 54° noord en suid van die ewenaar, waar hierdie gebiede by 34° S lê. Internasionale hops varieteite is nie aangepas by die Suid-Afrikaanse klimaat nie, want die winters is te warm en die daglengte in die somer is te kort. Al die variëteite in Suid Afrika is geteel vir dié spesifieke klimaatstoestande. Die Hopsteling en -navorsingprogram streef daarna om internasionaal mededingende varieteite met hoër opbrengste, verminderde insetkoste, verhoogde produktiwiteit en wenslike broueienskappe te ontwikkel. 'n Studie is gedoen om die effek van stropingstyd te evalueer en te identifiseer of hierdie praktyk negatiewe invloede op die gesondheid van plante en opbrengste het. Stroping verwys na die praktyk van die verwydering van basale groei van die laer laterale en onopgeleide ranke. Die studie is gedoen in twee verskillende mikroklimate, naamlik George en Waboomskraal. Die doel was om te bepaal wat die effek van stropingstyd op die vegetatiewe groei, lig onderskepping, biomassa, alfasure en betasure, opbrengs, wortelmassa en koolhidrate konsentrasies is. Die effek van stropingstyd was ook geëvalueer op verskillende plantsisteme en plant volwassenheid, naamlik Tramlyne en Konvensionele -plantsisteem, en 3 jaar oue teenoor 5 jaar oue plante. Die effek van vroeë stroping in terme van droë gewig op volwasse plante is aansienlik minder as die effek op jonger plante. Jong plante het laer droë gewig, maar hoër koolhidraat reserwes in die vroeë stroping behandeling gelewer. Vroë stroping van jong plante het ’n beduidende verskil getoon ten opsigte van opbrengste op die Tramlyn-plantsisteem. Daar is 'n algemene tendens op alle lokaliteite van hoër opbrengs doeltreffendheid in die vroeë stropings behandelings. Produsente, veral in die George area, kan opbrengste aansienlik verhoog sonder om die kwaliteit (alfa en beta sure) negatief te beïnvloed, deur die toepassing van vroeë stroping. Die effek van vroeë stroping word meer duidelik in agtereenvolgende jare, omdat die stropingstyd die koolhidrate konsentrasie, mikroklimaat binne in die hopranke en lig onderskepping wat lei tot verhoogde opbrengste, veral op die Tramlyn- plantsisteem, beïnvloed. Uit hierdie studie kan afgelei word dat vroeë stroping 'n invloed op die ligonderskepping, plantgewas doeltreffendheid, biomassa, opbrengs, droë wortelgewig en koolhidraatkonsentrasie het. Hierdie praktyk is nie net omgewingsvriendelik nie, maar gebruik minder onkruiddoder en lewer ekononomiese voordele vir die produsent. Die effek van stropingstyd op agtereenvolgende jare en verskillende varieteite verdien verdere studie.

American family life has undergone drastic changes over the last five decades. The median age at first marriage has risen sharply over that time, a trend that has attracted the attention of a number of family scholars. Less is known, however, about those who continue to marry early in a society where such a practice is increasingly rare and where the benefits to marriage during young adulthood are thought to be diminishing. In this dissertation, I ask specifically (a) what types of people continue to marry early in a context where delayed marriage is the norm, (b) how culture can impact marital timing, and (c) what effect marriage has on the mental health and well-being of young adults. To answer these questions, I analyze survey data primarily from the first and third waves of the National Longitudinal Study of Adolescent Health, a panel study of American adolescents that began in 1994-95 and tracked its respondents into young adulthood in 2001-02. The results suggest that a significant minority of young adults—25% of women and 16% of men—marry early, and early marriage occurs most frequently among young adults with low educational trajectories and who come from families with more limited resources. These young adults are typically found in rural communities and in the Southern United States, and they tend to identify with conservative religious traditions like conservative Protestantism and Mormonism. Culture, in the case of involvement in a religious community, can shape marriage timing by limiting the appeal of cohabitation, increasing marital desires and expectations, and by reducing perceived conflict between marriage and higher education. Moreover, a prevailing cultural schema that prescribes full time work as a prerequisite for marriage keeps even young adults who wish they were married from doing so. Finally, young adults who are married or engaged exhibit the best mental health in young adulthood. These findings suggest that demographic and cultural shifts in marriage have not spread evenly throughout the population, and despite its poor reputation early marriage may have some benefits for young adults. / text

Behavioral flexibility, the ability to change behavior in accordance with the changing environment, was studied in pigeons using a series of reversal learning paradigms. All experiments involved a series of 5-trial sequences and I was interested in whether pigeons are sensitive to the reversal by switching to the other alternative after a single error. In Experiments 1 and 2, the overall probability of the two stimuli was equated over sequences, but the probability correct of the two stimuli changed across trials. In both experiments, subjects showed no sensitivity to the differences in sequence type. Instead they used the overall average of the probability of reinforcement on each trial as the basis of choice. In the final two experiments, the likelihood that a reversal would occur on a given trial was equated such that there was an equal overall probability that the two stimuli would be correct on a given trial, but the overall probability of each stimulus being correct across sequences favored the second correct stimulus (S2). In Experiment 3, the overall probability of S2 correct was 80%, and results showed that subjects consistently chose S2 regardless of sequence type or trial number. In Experiment 4, the overall likelihood of S2 correct was 65%, and results showed that subjects began all sequences at chance, and as the sequence progressed, began choosing S2 more often. In all experiments, subjects showed remarkably similar behavior regardless of where (or whether) the reversal occurred in a given sequence. Therefore, subjects appeared to be insensitive to the consequences of responses within a sequence (local information) and instead, seemed to be averaging over the sequences based on the overall probability of reinforcement for S1 or S2 being correct on each trial (aggregate information), thus not maximizing overall reinforcement. Together, the results of this series of experiments suggest that pigeons have a basic disposition for using the overall probability instead of using local feedback cues provided by the outcome of individual trials. The fact that pigeons do not use the more optimal information afforded by recent reinforcement contingencies to maximize reinforcement has implications for their use of flexible response strategies under reversal learning conditions.

Even though that business plans are created every day, and that there is many literature on them, there is very little known on the process of the business plan development itself. Using a qualitative research method called autoethnography, this thesis explored the business plan development process. The main findings of this thesis were that there are four main themes or problems that can be associated with this process: problems regarding the data search and data collection; emotions; time constraints and the attractiveness of the idea.

Previous investigations comparing direct versus indirectly cued movements have consistently shown that indirectly cued movements take longer to prepare (Neely and Heath, 2010) and involve the recruitment of additional brain areas (Connolly et al., 2000). This increase in processing time has been associated with the additional cognitive transformations required of the task (Neely and Heath, 2010). In the present study we investigated whether differences between direct versus indirectly cued movements are also reflected in the time course of motor preparation. Participants performed a targeting task, moving directly to the location of a visual cue (i.e., directly cued movement) or to a location that differed by 60˚, 90˚, or 120˚ with respect to the visual cue provided (i.e., indirectly cued movements). Participants were instructed to initiate their movements concurrently with an anticipated go-signal. To examine the time course of motor preparation, a startling acoustic stimulus (SAS, 124dB) was randomly presented 150 ms, 500 ms, or 1000 ms prior to the go-signal. Results from the startle trials revealed that the time course of motor preparation was similar regardless of the angle of rotation required and hence whether it was a direct or indirectly cued trial. Specifically, motor preparation was delayed until less than 500 ms prior to movement initiation for both direct and indirectly cued movements. These findings indicate that similar motor preparation strategies are engaged for both types of cued movements, suggesting that the time to prepare a motor response may be similar regardless of whether a cognitive transformation is required.

Numerous experiments have demonstrated that the activity of neurons can alter the strength of excitatory synapses. This synaptic plasticity is bidirectional and synapses can be strengthened (potentiation) or weakened (depression). Synaptic plasticity offers a mechanism that links the ongoing activity of the brain with persistent physical changes to its structure. For this reason it is widely believed that synaptic plasticity mediates learning and memory. The hypothesis that synapses store memories by modifying their strengths raises an important issue. There should be a balance between the necessity that synapses change frequently, allowing new memories to be stored with high fidelity, and the necessity that synapses retain previously stored information. This is the plasticity stability dilemma. In this thesis the plasticity stability dilemma is studied in the context of the two dominant paradigms of activity dependent synaptic plasticity: Spike timing dependent plasticity (STDP) and long term potentiation and depression (LTP/D). Models of biological synapses are analysed and processes that might ameliorate the plasticity stability dilemma are identified. Two popular existing models of STDP are compared. Through this comparison it is demonstrated that the synaptic weight dynamics of STDP has a large impact upon the retention time of correlation between the weights of a single neuron and a memory. In networks it is shown that lateral inhibition stabilises the synaptic weights and receptive fields. To analyse LTP a novel model of LTP/D is proposed. The model centres on the distinction between early LTP/D, when synaptic modifications are persistent on a short timescale, and late LTP/D when synaptic modifications are persistent on a long timescale. In the context of the hippocampus it is proposed that early LTP/D allows the rapid and continuous storage of short lasting memory traces over a long lasting trace established with late LTP/D. It is shown that this might confer a longer memory retention time than in a system with only one phase of LTP/D. Experimental predictions about the dynamics of amnesia based upon this model are proposed. Synaptic tagging is a phenomenon whereby early LTP can be converted into late LTP, by subsequent induction of late LTP in a separate but nearby input. Synaptic tagging is incorporated into the LTP/D framework. Using this model it is demonstrated that synaptic tagging could lead to the conversion of a short lasting memory trace into a longer lasting trace. It is proposed that this allows the rescue of memory traces that were initially destined for complete decay. When combined with early and late LTP/D iii synaptic tagging might allow the management of hippocampal memory traces, such that not all memories must be stored on the longest, most stable late phase timescale. This lessens the plasticity stability dilemma in the hippocampus, where it has been hypothesised that memory traces must be frequently and vividly formed, but that not all traces demand eventual consolidation at the systems level.

<p>Humans and animals have remarkable capabilities in keeping time and using time as a guide to orient their learning and decision making. Psychophysical models of timing and time perception have been proposed for decades and have received behavioral, anatomical and pharmacological data support. However, despite numerous studies that aimed at delineating the neural underpinnings of interval timing, a complete picture of the neurobiological network of timing in the seconds-to-minutes range remains elusive. Based on classical interval timing protocols and proposing a Timing, Immersive Memory and Emotional Regulation (TIMER) test battery, the author investigates the contributions of the dorsal and ventral hippocampus as well as the dorsolateral and the dorsomedial striatum to interval timing by comparing timing performances in mice after they received cytotoxic lesions in the corresponding brain regions. On the other hand, a timing-based theoretical framework for the emergence of conscious experience that is closely related to the function of the claustrum is proposed so as to serve both biological guidance and the research and evolution of “strong” artificial intelligence. Finally, a new “Double Saturation Model of Interval Timing” that integrates the direct- and indirect- pathways of striatum is proposed to explain the set of empirical findings.</p> / Dissertation

The aim of this article is to examine the relations between two approaches to the measurement of life history (LH) strategies: A traditional approach, termed here the biodemographic approach, measures developmental characteristics like birthweight, gestation length, interbirth intervals, pubertal timing, and sexual debut, and a psychological approach measures a suite of cognitive and behavioral traits such as altruism, sociosexual orientation, personality, mutualism, familial relationships, and religiosity. The biodemographic approach also tends not to invoke latent variables, whereas the psychological approach typically relies heavily upon them. Although a large body of literature supports both approaches, they are largely separate. This review examines the history and relations between biodemographic and psychological measures of LH, which remain murky at best. In doing so, we consider basic questions about the nature of LH strategies: What constitutes LH strategy (or perhaps more importantly, what does not constitute LH strategy)? What is gained or lost by including psychological measures in LH research? Must these measures remain independent or should they be used in conjunction as complementary tools to test tenets of LH theory? Although definitive answers will linger, we hope to catalyze an explicit discussion among LH researchers and to provoke novel research avenues that combine the strengths each approach brings to this burgeoning field.