Effect of Ablatant Composition on the Ablation of a Fuelling Pellet

The single species neutral-shielding model for the ablation of a hydrogenic pellet is extended by considering the ablatant as a mixture of four species: molecular and atomic hydrogen, protons and electrons. Compared with the results of the frozen flow, (i.e. the single species molecular hydrogen gas model), results of the analysis showed that the presence of dissociation and ionization effects caused a marked difference of the ablatant state. The attenuations of the incominq electron energy and energy flux, however, are very much similar irrespective of whether the ablated flow is in a frozen or an equilibrium state. The scaling law of the pellet ablation rate with respect to the plasma state of Te, ne and the pellet radius remains the same; the ablation rate is reduced bv approximately 15%. To examine the possible existence of a spherical shell around the pellet where most of the incoming electron energy is absorbed, a comparison is made between the local electron collisional mean free path and the electron Larmor radius. A critical field at the ionization radius is evaluated. An effective spherical energyabsorbing region exists when the local field strength is below the critical value. For a plasma state of low Te and ne, (where the ablatant is hardly ionized), and for one near the thermonuclear condition (where a highly dense ablatant exists near the pellet), the effective energy absorption region is nearly spherical

Performance Analysis of Dual Unipolar/Bipolar Spectral Code in Optical CDMA Systems

This study analyzes and calculates dual unipolar and bipolar coded configurations of spectral-amplitude-coding opticalcode division multiple access (SAC-OCDMA) systems by using simulation methods. The important feature of theSAC-OCDMA systems is that multiple access interference (MAI) can be eliminated by code sequences of a fixed inphasecross-correlation value. This property can be effectively canceled multiple access interference by using balancedetection schemes. This study uses Walsh-Hadamard codes as signature codes for the unipolar and bipolar schemes.The coder and decoder structures are based on optical filters of fiber Bragg gratings (FBGs). The simulation results ofunipolar/bipolar coding structures are first presented by commercial simulation obtained using OptiSystem software.The simulation results show that the bit error rate (BER) through use of the bipolar coding method is superior to theunipolar scheme, especially when the received effect power is large. When the system needs good performance totransmit multimedia data, we can use bipolar scheme in the network. If the users only transmit voice data, the unipolarmethod can be employed. The eye diagram also shows that the bipolar encoding structure exhibits a wider openingthan the unipolar encoding structure. The flexible implementation of codewords assigns and integratable hardwaredesigns for the scheme with FBGs to realize dual coding OCDMA system is proposed

Management based on exhaled nitric oxidelevels adjusted for atopy reduces asthma exacerbations in children : A dual centre randomised controlled trial

While several randomised control trials (RCTs) have evaluated the use of fractional exhaled nitric oxide (FeNO) to improve asthma outcomes, none used FeNO cut-offs adjusted for atopy, a determinant of FeNO levels. In a dual centre RCT, we assessed whether a treatment strategy based on FeNO levels, adjusted for atopy, reduces asthma exacerbations compared with the symptoms-based management (controls). Children with asthma from hospital clinics of two hospitals were randomly allocated to receive an a-priori determined treatment hierarchy based on symptoms or FeNO levels. There was a 2-week run-in period and they were then reviewed ten times over 12-months. The primary outcome was the number of children with exacerbations over 12-months. Sixty-three children were randomised (FeNO=31, controls=32); 55 (86%) completed the study. Although we did achieve our planned sample size, significantly fewer children in the FeNO group (6 of 27) had an asthma exacerbation compared to controls (15 of 28), p=0.021; number to treat for benefit=4 (95%CI 3-24). There was no difference between groups for any secondary outcomes (quality of life, symptoms, FEV1). The final daily inhaled corticosteroids (ICS) dose was significantly (p=0.037) higher in the FeNO group (median 400µg, IQR 250-600) compared to the controls (200, IQR100-400). Taking atopy into account when using FeNO to tailor asthma medications is likely beneficial in reducing the number of children with severe exacerbations at the expense of increased ICS use. However, the strategy is unlikely beneficial for improving asthma control. A larger study is required to confirm or refute our findings

Predictors of physical activity for weekdays and weekends among adolescent – a cross-sectional study in Sarawak, Malaysia

This study aimed to describe the patterns of physical activities both at weekends and on weekdays and to identify their associated factors. Material/Methods This was a cross-sectional study conducted among secondary school students aged 13-15 years old in Kuching Division, Sarawak, Malaysia. A self-administered questionnaire was used to collect socio-demographic information and to measure perceived barriers, self-efficacies and social influences. Anthropometric measurements were taken and used to determine BMI-for-age, while pedometers were used to assess the physical activity levels. Data were analyzed using SPSS. Results A total of 474 students from six secondary schools participated. About 16% of the respondents were overweight and obese, majority of them males. The mean BMI was 21.21±12.93, higher among males. The mean steps per day were 6251.37±3085.31, with weekends recorded a higher number of steps. The number of steps among males was higher than among females. On weekdays, self-motivation scores significantly predicted the participants’number of steps/physical activity rate (b = 521.43, 95% CI -72.78 to 1050.19). At weekends, lack of interest and knowledge scores (b = -427.82, 95% CI -837.72 to 17.92) and making choices scores (b = 737.41, 95% CI -197.94 to 1276.88) were significant to predict the number of steps/physical activity levels. Conclusions These findings indicated the importance of investigating predictors of physical activity for weekdays and weekends. Thus, efforts should focus on how to motivate adolescents to be more physically active targeting the identified predictors for weekdays and week ends