Likelihood-Based Confidence Sets for the Timing of Structural Breaks

In this paper, we propose a new approach to constructing confidence sets for the timing of structural breaks. This approach involves using Markov-chain Monte Carlo methods to simulate marginal “fiducial” distributions of break dates from the likelihood function. We compare our proposed approach to asymptotic and bootstrap confidence sets and find that it performs best in terms of producing short confidence sets with accurate coverage rates. Our approach also has the advantages of i) being broadly applicable to different patterns of structural breaks, ii) being computationally efficient, and iii) requiring only the ability to evaluate the likelihood function over parameter values, thus allowing for many possible distributional assumptions for the data. In our application, we investigate the nature and timing of structural breaks in postwar U.S. Real GDP. Based on marginal fiducial distributions, we find much tighter 95% confidence sets for the timing of the so-called “Great Moderation” than has been reported in previous studies.Fiducial Inference; Bootstrap Methods; Structural Breaks; Confidence Intervals and Sets; Coverage Accuracy and Expected Length; Markov-chain Monte Carlo;

A Particle Image Velocimetry study of dual-rotor counter-rotating wind turbine near wake

This experimental work studied the flow characteristics in the near wake region behind dual-rotor wind turbines using two-dimensional particle image velocimetry. Two auxiliary rotors of 50% and 80% scale of the main rotor were installed upwind and operated in counter-rotating condition, which are compared to the conventional single rotor turbine. In all the three configurations, a constant Reynolds number 9.5×104 was applied and all the rotors operated at a fixed tip speed ratio of 3.46. The mean and phase averaged velocity fields were investigated together with the turbulence kinetic energy. It was found that the two auxiliary rotors do not result in a significantly different wake flow property. The configuration implementing the 50% auxiliary rotor sees a slightly better wake characteristics, in terms of weaker main rotor tip vortices and a counter-rotating swirling shear region at the mid-span behind the main rotor. The decay rates of the peak vorticity of the main rotor tip vortices and their circulation are found to follow an exponential manner

Spectrophotometeric determination of bromate in bread by the oxidation of dyes

A spectrophotometric method for the determination of bromate based on the oxidation of congo red and crystal violet dyes in a hydrochloric acid medium is described. The bromate level in bread samples determined range from 3.70 µg g-1 to 12.10 µg g-1; with limits of quantification of 0.45 – 0.78 µg g-1. Results show the presence of detectable residue levels of potassium bromate in all the bread samples analysed and the results compare favourably with established AOAC method. Journal of Applied Sciences and Environmental Management Vol. 10 (3) 2006: 43-4

Power Factor Correction for Thyristor Equipment in Glass Industry

Thyristor power controllers are now widely used in the glass industry for controlling furnace temperature. While offering a number of operational advantages, they operate at lagging power factors which require correction for minimum power cost. Harmonic resonance with the utility feed, however, complicate the use of capacitor banks. The nature of harmonic problems is described and the use of inductors to tune capacitor banks below any possible harmonic frequency is demonstrated.The Information Manager Vol. 8 (1) 2008: pp. 22-2

Winter habitat use of New Zealand falcons (Falco novaeseelandiae ferox) in an intensively managed pine plantation, central North Island, New Zealand

Copyright and source must be acknowledgedPublishe

Knowledge, Attitude and Willingness to Participate in Gamete Donation for Artificial Insemination among Undergraduate Students in Lagos

Background: Infertility affects one-fifth to one-sixth of couples of reproductive age. Gamete donation is one option for managing infertility, but it is relatively unknown in the developing world. Objectives: To assess Nigerian undergraduate students' knowledge, attitude and willingness to participate in gamete donation for artificial insemination. Methods: A descriptive cross-sectional study was conducted among 160 undergraduate students using a semi-structured self-administered questionnaire. The respondents were recruited using a multi-stage sampling technique. Results: The mean age of the respondents was 21.5±3.2 years, with a range of 18-32 years. The majority (89.4%) of the respondents were single and were in the first year of study (56.3%). Almost all the respondents (96.3%) had heard about the practice of gamete donation, but only (38.7%) had overall good knowledge about it. Almost half (46.9%) of respondents had an overall positive attitude towards gamete donation, while only 37.5% were willing to participate. The class level of the respondents (p = 0.03) was significantly associated with poor knowledge of gamete donation, while age (p = 0.01) and gender (p < 0.001) were associated with a negative attitude. Age (p<0.001) was also significantly associated with poor willingness to participate. Conclusion: The respondents' awareness of gamete donation was high, but their knowledge was poor, leading to a negative attitude and poor willingness to participate. Public enlightenment on gamete donation for artificial insemination should be intensified

Importance of knowledge capturing (KC) in the design briefing process in the construction industry

Construction is a major contributor to UK GDP (directly 8.5% in 2008, rising to 10% overall when the entire value chain is considered) and a driver of historical GDP growth. The sector employs over 3 million people in a multitude of roles representing 8% of UK employment and a significant proportion of construction employees. The construction industry operates in stages and one of which is the pre-design stage. The pre-design stage is an important phase of the construction process because this is where the client brief is written up and major decisions are made. An effective client briefing process is important to the attainment of client objectives with respect to time, cost and quality for construction projects. Through a critical review of literature. Research shows that despite several research conducted in the area of knowledge management, it has unfortunately, not been matched by parallel empirical research on the processes, challenges and benefits of knowledge capture (KC) in the design briefing process within the construction industry. As a result of this, many projects end up under performing and not matching up to the expected goals and objectives highlighted by the client. This goes on to ascertain that inadequate attention given to the knowledge capturing process during the design briefing can be a major deterrent to the output of a construction project which can in turn lead to highly dissatisfied clients and loss of contract for some organizations. This paper presents the importance and likely barriers associated with knowledge capturing during the client briefing process and the impact poorly run design briefing process has on the output of a construction project

Changes in serum lactate to aerobic exercise among amateur athletes and non-athletes

Lactate is an end product of glucose metabolism that is usually produced in a larger quantity during exercise. This increase in production during exercise has been understood to be the reason for fatigue. The aim of this study is to determine the responses of serum lactate to aerobic exercise among amateur athletes and non-athletes. 48 consenting males (24 amateur athletes and 24 non-athletes) participated in this comparative quasi-experimental design. Subjects cycled on a bicycle ergometer to attain moderate intensity exercise target heart rate (MIETHR) and maintained the MIETHR till exhaustion (15 on Borgs scale or volitional exertion) while the serum lactate was measured at intervals. Data were analyzed with descriptive statistics and inferential statistics of Analysis of variance (ANOVA). Alpha level was set at p < 0.05. The mean age of the participants was 26.08±2.28 and 28.13±1.51 for the athletes and non-athletes respectively. There was a significant difference p=0.001 Training induced adaptations include a lower serum lactate level, a point that should be noted in studying of metabolic adaptations.Keywords: Lactate, Athletes, Exercise, Response, Fitnes