Deconvolution of Mono-Energetic and Multi-Lines Gamma-Ray Spectra Obtained with NaI(Tl) Scintillation Detectors Using Direct Matrix Inversion Method

Performance of a NaI(Tl) scintillation detector based on the gamma-ray spectroscopy system is not satisfactory in retaining its original peak (which is delta like function) of various gamma ray spectrum. The method of achieving precise peak for the various gamma ray was conducted by converting the observed pulse-height distribution of the NaI(Tl) detector to a true photon spectrum. This method is obtained experimentally with the help of an inverse matrix deconvolution method. The method is based on response matrix generated by the Monte Carlo simulation based on Geant4 package of mono-energy gamma-ray photon ranging from 0.050 to 2.04 MeV in the interval of 10 keV. The comparison of the measured and simulated response function was also performed in order to authenticate the simulation response function. Good agreement was observed around the photo-peak region of the spectrum, but slight deviation was observed at low energy region especially below 0.2 MeV. The Compton backscattering and Compton continuum counts was significantly transferred into the corresponding photo-peak and consequently the peak to total(P/T) ratio was improved. The P/T ratio results obtained after application of the deconvolution method taken with three calibration sources with gamma-ray’s energies of 81 keV, 303 keV and 356 keV (for 133Ba), 662 keV (for 137Cs), 1173 keV and 1333keV (for 60Co), were improved from(to) 0.50(0.90), 0.40(0.83), 0.57(0.93), 0.31(0.92), 0.18(0.84) and 0.15(0.83), respectively

Comparison of Experimental and Monte Carlo Simulation of Angular Distributions of Bremsstrahlung Photons from 28-GHZ Electron Cyclotron Resonance (ECR) Ion Source

Angular distributions of deceleration radiation or bremsstrahlung in German, both experimental and simulated from Electron Cyclotron Resonance Ion Source (ECRIS) are not well understood so far. The bremsstrahlung photons of the angular distributions from 28-GHz ECR ion source at Busan Centre of Korea Basic Science Institute (KBSI) were measured in nine azimuthal angles for the first time. Three round type NaI(Tl) detectors were used to measure the angular distributions of the bremsstrahlung photons emitted at the extraction side of the ECRIS at the same time. Another NaI(Tl) detector was placed downstream from the ECR ion source for monitoring photon intensity. The ECR ion source was operated at RF power of 1 kW. Monte Carlo simulation based on Geant4 package was performed to study the angular distributions of the bremsstrahlung photons. The simulation was based on a full geometry of the ECR ion source. Geant4 simulation was executed to take the geometrical acceptance and energy-dependent detection efficiency into account due to large non-uniformity in the material budget. True bremsstrahlung energy spectra from the 28-GHz ECR ion source were obtained using the inverse-matrix deconvolution method. The deconvolution method was based on a full geometry of the Geant4 model of the ECR ion source. It is interesting to observe that the maximum simulated photon yields at angle 150° was correlated with the measured photon yields at angle 150° at the extraction side, which can be explained by the internal structure and shape of the ECR plasma. Keywords: Angular distribution; Bremsstrahlung photons; Deconvolution; ECRIS; Geant4 simulation; NaI(TI) detectors; RF power

Social media, ethics and development in the postmodernist Malawian society

The paper argues that in the postmodernist era, there is great likelihood for people to use social media networks for wrong reasons rather than for promoting “the good” as the great Greek Philosopher, Plato, would demand. This is so because the ultimate goal of a postmodernist society is a commercial one, which is chiefly characterized by a high spirit of competition and general loss of holiness. The paper observes that in a postmodernist society, the people are greatly motivated by the trendy and that there is dominance of the non-realistic aspects, which lead them to lose their sense of humanity. In most cases, the people become mechanical in their pursuit of happiness, wealth and power. At the same time, subscription to the non-realistic aspects of life compels them to be continuous seekers of knowledge. As a result, this aspect makes it possible for nations whose economies are largely knowledge based to thrive. Hence, as more and more people embrace social media, development accelerates while the people lose their long cherished sense of virtue. Thus, social media is a necessary evil in the postmodernist era. After all, the end justifies the means.Key words: postmodernism, the queer, hyperreality, sublimation, de-individuatio

Factors affecting tuberculosis health message recall 2 years after active case finding in Blantyre, Malawi.

SETTING: Urban slums, Blantyre, Malawi. OBJECTIVE: To explore tuberculosis (TB) community-wide active case finding (cwACF) recall and accompanying messaging 2 years after the intervention. DESIGN: This mixed-methods study used population-weighted random cluster sampling to select three cwACF-receiving and three non-cwACF-receiving neighbourhoods in Blantyre. Qualitative data were collected using 12 focus group discussions (community peer-group members) and five in-depth interviews (TB officers) with script guides based on the concepts of the Health Belief Model (HBM). Thematic analysis was used to explore transcripts employing deductive coding. Questionnaires completed by focus group participants were used to collect quantitative data, providing a 'knowledge score' evaluated through univariate/multivariate analysis, analysis of variance and multiple linear regression. RESULTS: Community peer-group participants (n = 118) retained high awareness and positive opinions of cwACF and recognised the relationship between early diagnosis and reduced transmission, considering cwACF to have prompted subsequent health-seeking behaviour. TB-affected individuals (personal/family: 47.5%) had significantly higher knowledge scores than unaffected individuals (P = 0.039), but only if resident in cwACF-receiving neighbourhoods (P = 0.005 vs. P = 0.582), implying effect modification between exposures, albeit statistically under-powered (P = 0.229). CONCLUSION: Consistent with epidemiological evidence and HBM theory, cwACF may have a permanent impact on knowledge and behaviour, particularly in communities with a high prevalence of TB-affected individuals. Behaviour change strategies should be explicitly included in cwACF planning and evaluation

Atmospheric Instability Conditions during Rainy Seasons over Tanzania

The amount of rainfall and its distribution in time and space is dependent on the atmospheric instability conditions, and on its moisture content. The aim of this study was to determine the atmospheric instability conditions during January to March (JFM), February to April (FMA), March to May (MAM), and October to December (OND) rainy seasons over local climate zones in Tanzania. Zone area average seasonal Convective Available Potential Energy (CAPE), Convective Inhibition (CIN), Precipitable Water (PW) and Lifted index (Li) were calculated and analyzed. Results showed Li < 0 in JFM and FMA over whole Tanzania. During MAM and OND, Li < 0 over the Lake Zone, Western Highlands Zone and Central Zone only. CAPE ranged from 793 J/kg to 1183 J/kg during JFM, and 700 J/kg to 1080 J/kg during FMA. During MAM, CAPE ranged from 170 J/kg to 921 J/kg and from 173 J/kg to 833 J/kg during OND. Results also showed CAPE > 1000 J/kg over the Lake Zone, Western Highlands Zone, Island Zone, and Central Zone. These results show that the atmosphere was moderately unstable during the JFM and FMA and was weakly unstable during the MAM and OND. Therefore, the atmosphere is likely to be more convective during JFM and FMA seasons. Keywords: Lifted index, Convective inhibition, Precipitable water, Convective available potential energy, Atmospheric instability

Reducing child undernutrition through dietary diversification, reduced aflatoxin exposure, and improved hygiene practices: the immediate impacts in central Tanzania

Open Access Article; Published online: 28 Nov 2019The study aimed to quantify the immediate effects of dietary diversification, food safety, and hygiene interventions on child undernutrition in four rural villages in Kongwa district of central Tanzania. One hundred mothers with their children of less than 24 months old were recruited for this study. The difference-in-difference (DID) method was used to assess the effects of intensive intervention through a learning-by-doing process on the topic of aflatoxin free diversified food utilization and improved hygiene practices. Periodic anthropometric measurements were conducted on the 0th, 7th, 14th, and 21st days, and DID estimator showed the significant and positive average marginal effects of the intervention on Z-Scores being 0.459, 0.252, and 0.493 for wasting, stunting, and underweight, respectively. Notably, at the end of the study, the mean aflatoxin M1 level in urine samples decreased by 64% in the intervention group, while it decreased by 11% in the control group. The study provides quantitative evidence on intensive 21-day training for mothers incorporating integrated technologies yielded positive impacts on their children’s nutritional outcomes

The relationship between school type and academic performance at medical school:A national, multi-cohort study

Acknowledgements We thank UKMED for releasing the data for this project via a competitive bid process. We are grateful to the following for their support of the application to UKMED for this and other research projects: Dr Sally Curtis (University of Southampton, UK), Dr Sandra Nicholson (Barts and The London School of Medicine and Dentistry, UK), Professor Peter Johnston (NHS Education for Scotland, UK) and Dr Rhoda MacKenzie (University of Aberdeen, UK). We thank Daniel Smith and Andy Knapton of the General Medical Council of the UK for their support for the application and throughout the project, particularly regarding data linkage and troubleshooting. We thank Dr Gordon Prescott (University of Aberdeen, UK) for the statistical support. Funding This study is part of Ben Kumwenda’s doctoral programme of research funded by the UKCAT Research Panel, of which JC and RG are members.Peer reviewedPublisher PD

Relationship between sociodemographic factors and specialty destination of UK trainee doctors:a national cohort study

We are grateful to UKMED for releasing the data for this project. We also are grateful to the following for their support of the application to UKMED for this and other research projects: Dr Sally Curtis (University of Southampton, UK), Dr Sandra Nicholson (Barts and The London School of Medicine and Dentistry, UK). We thank Daniel Smith and Andy Knapton of the General Medical Council of the UK for their support for the application and throughout the project, particularly regarding data linkage and troubleshooting.Peer reviewedPublisher PD