Thirty recreationally active individuals, 16 males and 14 females, participated in the study to examine the effects of policosanol supplementation on reaction time, force production and the blood lipid profile. The subjects were matched based on height, weight. gender, current physical activity level and body fat percentage. The matched subjects where randomly assigned to either the policosanol or placebo group. Supplementation period lasted 8 weeks with reaction and decision time measurements taken at baseline, weeks 2, 4, 6 and 8. Force production was evaluated with the Cybex Dynamometer at speeds of 60, 120, 180 and 240 degrees/second at baseline, weeks 2, 4, 6 and 8. Blood was drawn and analyzed at baseline, weeks 4 and 8. A two way repeated analysis of variance was used to analyze differences between pre and post measurement at a significance level of p <_ .05. There were no significant changes in reaction ordecision time between groups. Force production significantly increased in both groups however, there was no significance between groups. The blood analysis demonstrated significant changes in total cholesterol and triglycerides. No differences were found in high-density lipoprotein cholesterol, low-density lipoprotein cholesterol or liver function measurements. It was concluded that further research in needed to examine the effects of reaction time in older individuals with possibly slower reaction times. The increase in force was due to a training effect and not from policosanol supplementation. However, future research with policosanol and strength needs to incorporate a training protocol. The trend observed with the blood parameters was concluded be a normalizing effect rather than a lowering effect. / School of Physical Education

Wright and Adams (1994; 1999) developed a Choice Reaction Time measure to assess sexual interests in men and women. In their studies, men responded in accordance to their self-reported sexual interests much more consistently than women. Placing these results in the framework of objectification theories (e.g., Fredrickson & Roberts, 1997), the present study was designed to examine the relationship between body image and young women's CRT responses.Forty-two females participated in the CRT task. Consistent with previous studies, 21 (50%) of the women took longer to respond on male trials than female trials. These women were compared to those who took longer on female trials on all the body image and sexuality measures using ANOVA's. Results indicated no significant differences on any of the body image measures, but a small number of differences on sexuality measures. Results are discussed in terms of their implications for gender differences in sexual interest. / Department of Psychological Science

Biofuels are becoming more attractive worldwide because of the high energy demands and the fossil fuel resources that are being depleted. Biodiesel is one of the most attractive alternative energy sources to petroleum diesel fuel and it is renewable, non toxic, biodegradable, has low sulphur content and has a high flash point. Biodiesel can be generated from domestic natural resources such as coconuts, rapeseeds, soybeans, sunflower, and waste cooking oil through a commonly used method called transesterification. Transesterification is a reaction whereby oil (e.g. sunflower oil) or fats react with alcohol (e.g. methanol) with or without the presence of a catalyst (e.g. potassium hydroxide) to form fatty acid alkyl esters (biodiesel) and glycerol. The high-energy input for biodiesel production remains a concern for the competitive production of bio-based transportation fuels. However, microwave radiation is a method that can be used in the production of biodiesel to reduce the reaction time as well as to improve product yields. Sunflower oil is one of the biodiesel feedstocks that are used in South Africa and is widely used in cooking and for frying purposes. This study aims to use microwave irradiation to reduce the energy input for biodiesel production. The effect of various reaction variables, including reaction time (10 – 60 seconds), microwave power (300 – 900 watts), catalyst (potassium hydroxide) loading (0.5 – 1.5 wt%) and methanol to oil molar ratio (1:3 – 1:9) on the yield of fatty acid methyl ester (biodiesel) was investigated. The quality of biodiesel produced was analysed by Gas Chromatography (GC), Fourier Transform Infrared Spectroscopy (FTIR) and viscometry. The FTIR results confirmed the presence of functional groups of the FAME produced during transesterification. The results showed that transesterification can proceed much faster under microwave irradiation than when using traditional heating methods. The interaction between the alcohol and oil molecules is significantly improved, leading to shorter reaction times (seconds instead of hours) and improved diesel yields. The highest biodiesel yield obtained was 98% at 1:6 oil-to-methanol molar ratio for both 1 wt% and 1.5 wt% potassium hydroxide (KOH) at a reduced reaction time (30 seconds). The chemical composition of FAME (biodiesel) obtained from different conditions i contained palmitic acid (C16:0), stearic acid (C18:0), oleic acid (C18:1) and 70% linoleic acid (C18:2). The physical properties (cetane number, viscosity, density and FAME content) of biodiesel produced met the SANS 1935 specification. The energy consumption was reduced from 1.2 kWh with the traditional transesterification to 0.0067 kWh with the microwave transesterification. Microwave irradiation was shown to be effective in significantly lowering the energy consumption for production of biodiesel with good quality for small scale producers. / Thesis (MSc (Engineering Sciences in Chemical Engineering))--North-West University, Potchefstroom Campus, 2013

Biofuels are becoming more attractive worldwide because of the high energy demands and the fossil fuel resources that are being depleted. Biodiesel is one of the most attractive alternative energy sources to petroleum diesel fuel and it is renewable, non toxic, biodegradable, has low sulphur content and has a high flash point. Biodiesel can be generated from domestic natural resources such as coconuts, rapeseeds, soybeans, sunflower, and waste cooking oil through a commonly used method called transesterification. Transesterification is a reaction whereby oil (e.g. sunflower oil) or fats react with alcohol (e.g. methanol) with or without the presence of a catalyst (e.g. potassium hydroxide) to form fatty acid alkyl esters (biodiesel) and glycerol. The high-energy input for biodiesel production remains a concern for the competitive production of bio-based transportation fuels. However, microwave radiation is a method that can be used in the production of biodiesel to reduce the reaction time as well as to improve product yields. Sunflower oil is one of the biodiesel feedstocks that are used in South Africa and is widely used in cooking and for frying purposes. This study aims to use microwave irradiation to reduce the energy input for biodiesel production. The effect of various reaction variables, including reaction time (10 – 60 seconds), microwave power (300 – 900 watts), catalyst (potassium hydroxide) loading (0.5 – 1.5 wt%) and methanol to oil molar ratio (1:3 – 1:9) on the yield of fatty acid methyl ester (biodiesel) was investigated. The quality of biodiesel produced was analysed by Gas Chromatography (GC), Fourier Transform Infrared Spectroscopy (FTIR) and viscometry. The FTIR results confirmed the presence of functional groups of the FAME produced during transesterification. The results showed that transesterification can proceed much faster under microwave irradiation than when using traditional heating methods. The interaction between the alcohol and oil molecules is significantly improved, leading to shorter reaction times (seconds instead of hours) and improved diesel yields. The highest biodiesel yield obtained was 98% at 1:6 oil-to-methanol molar ratio for both 1 wt% and 1.5 wt% potassium hydroxide (KOH) at a reduced reaction time (30 seconds). The chemical composition of FAME (biodiesel) obtained from different conditions i contained palmitic acid (C16:0), stearic acid (C18:0), oleic acid (C18:1) and 70% linoleic acid (C18:2). The physical properties (cetane number, viscosity, density and FAME content) of biodiesel produced met the SANS 1935 specification. The energy consumption was reduced from 1.2 kWh with the traditional transesterification to 0.0067 kWh with the microwave transesterification. Microwave irradiation was shown to be effective in significantly lowering the energy consumption for production of biodiesel with good quality for small scale producers. / Thesis (MSc (Engineering Sciences in Chemical Engineering))--North-West University, Potchefstroom Campus, 2013

In a visual search experiment, the subject must find a target item hidden in a display of other items, and their performance is measured by their reaction time (RT). Here I look at how visual search reaction times are correlated with past reaction times. Target-absent RTs (i.e. RTs to displays that have no target) are strongly correlated with past target-absent RTs and, treated as a time series, have a 1/f power spectrum. Target-present RTs, on the other hand, are effectively uncorrelated with past RTs. A model for visual search is presented which generates search RTs with this pattern of correlations and power spectra. In the model, search is conducted by matching search items up with ¿categorizers,¿ which take a certain time to categorize each item as target or distractor; the RT is the sum of categorization times. The categorizers are drawn at random from a pool of active categorizers. After each search, some of the categorizers in the active pool are replaced with categorizers drawn from a larger population of unused categorizers. The categorizers that are not replaced are responsible for the RT correlations and the 1/f power spectrum.

Tyrimo tikslas - įvertinti klausos negalią turinčių sportuojančių ir nesportuojančių vyrų psichomotorinės reakcijos ir hemodinamikos rodiklius, priklausomai nuo fizinio krūvio bei kurtumo pobūdžio. Tyrimo hipotezė - įvertinus sportuojančių ir nesportuojančių vyrų su klausos negalia psichomotorinės reakcijos rodiklius po fizinio krūvio mėginio, reakcijos laikas nesportuojančių grupėje bus ilgesnis, o lyginant pagal kurtumo pobūdį, sportuojančių asmenų, turinčių įgytą kurtumą, reakcijos laikas bus trumpesnis. Tyrimo uždaviniai: 1. Įvertinti sportuojančių vyrų su klausos negalia, paprastosios ir sudėtingosios reakcijos laikus prieš ir po krūvio mėginio ir palyginti su nesportuojančių vyrų, turinčių klausos negalią, rodikliais. 2. Nustatyti klausos negalią turinčių sportuojančių vyrų psichomotorinės paprastosios ir sudėtingosios reakcijos laiką, priklausomai nuo kurtumo pobūdžio prieš ir po krūvio mėginio. 3. Įvertinti klausos negalią turinčių sportuojančių vyrų hemodinamikos rodiklių (dvigubos sandaugos), paprastosios ir sudėtingos reakcijos pokyčius, taikant 6 minučių ėjimo testą, priklausomai nuo kurtumo pobūdžio. Tyrimo metodika. Tyrime dalyvavo 22 jauno amžiaus kurtumo negalią turintys vyrai. Tiriamąją grupę sudarė kurčiųjų krepšinio rinktinės žaidėjai (amžius 23,80±2,6 metai), (45,5 proc., n=10), kontrolinę grupę – nesportuojantys, kurtumo negalią turintys vyrai (amžius 21,75±1,8 metai), (54,5 proc., n=12). Tyrimai buvo atlikti LSU Judesių valdymo laboratorijoje naudojant... [toliau žr. visą tekstą] / The aim of the study was – to evaluate psychomotor reactions and hemodynamic indices of sporstmen with hearing impairment and male persons who did not go in for sport. Hypothesis – The time of psychomotor reaction comparing sporstmen and people who do not do sports with hearing impairment subject to physical strain the time will be longer of those who do not go in for sport. And according deafness nature the reaction time will be longer in the group of sporstmen subject to acquired deafness nature. Objectives of the study: 1. To evaluate the time of simple and complex reaction before and after strain sample of sportsmen with hearing impairment and people who do not do sports with hearing impairment. 2. To estimate psychomotoric simple and complex reaction time of sportsmen with hearing impairment, subject to deafness nature before and after strain sample. 3. To evaluate hemodynamic parameters (double product) simple and complex reaction change of sportsmen with hearing impairment invoking 6 min. walking test subject to deafness nature. Research methods. Twenty two young people with hearing impairment took part in the study. There were deaf national basketball team players in the searching group (age 23,80±2,6), (45,5%., n=10), People with hearing impairment who do not go in for sport were in a control group (age 21,75±1,8 ), (54,5%., n=12). Researches were made in Lithuanian sports university (LSU) using analyser (DPA – 1) (p. No. 5251; 2005 08 25) of human hands and... [to full text]

The ability to navigate with limited vision is a skill that is often employed in our daily lives. Navigating without vision to a remembered target has previously been studied. However, not much is known about the attention required to perform blind navigation. We examined the effect of aging and presence of obstacles on the attentional demands of blind navigation. We evaluated reaction time, navigation errors and average walking speed in an 8 meter walking path, with or without obstacles, in the absence of vision. Results showed that older participants had increased reaction time and increased linear distance travelled as opposed to young participants, that obstacles increased reaction time and decreased average walking speed in all participants, and that emitting the reaction time stimulus early in the trial increased the linear distance travelled. Interpretation of the results suggests that aging and presence of obstacles augments the attentional demands of blind navigation.

Bibliography: leaves 194-220. / xv, 220 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Psychology, 1995?

xii, 179 leaves : tables ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.1979) from the Dept. of Psychology, University of Adelaide

xii, 179 leaves : tables ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.1979) from the Dept. of Psychology, University of Adelaide