45 research outputs found
Investigation of Dyed Film Based on Quinaldine Red Dyed Poly(Vinyl Alcohol) and Poly(Vinyl Butyral) for High Dose Dosimetry Applications
No full textStudy of Ag nanoparticles in a polyacrylamide hydrogel dosimeters by optical technique
No full textThe dosimetric characteristics of hydrogel dosimeters based on polyacrylamide (PAC) as a capping agent incorporating silver nitrate as a radiation-sensitive material are investigated using UV-Vis spectrophotometry within the dose range 0–100 Gy. Glycerol was used in the hydrogel matrix to promote the dosimetric response and increase the radiation sensitivity. Upon exposing the PAC hydrogel to γ-ray, it exhibits a Surface Plasmon Resonance (SPR) band at 453 nm, and its intensity increases linearly with absorbed doses up to 100 Gy. The results are compared with the silver nitrate gel dosimeter. Glycerol of 15% in the hydrogel matrix enhances the radiation sensitivity by about 30%. PAC hydrogel dosimeter can be considered a near water equivalent material in the 400 keV–20 MeV photon energy range. At doses less than 15 Gy, the PAC hydrogel dosimeter retains higher radiation sensitivity than the gel dosimeter. The total uncertainty (2σ) of the dose estimated using this hydrogel is about 4%. These results may support the validity of using this hydrogel as a dosimeter to verify radiotherapy techniques and dose monitoring during blood irradiation
Survivability and Impairment-aware Routing in Optical Networks: An Algorithmic Study
No full textOptical networks employing Wavelength Division Multiplexing (WDM) technology allow the multiplexing of several independent wavelength channels into a fiber. Since each wavelength channel operates independently at several Gb/s, WDM optical networks offer a tremendous transport capacity (which is in the order of several Tb/s), which makes them suitable candidates for future networks. A lightpath is made up of wavelength channels between the source and destination nodes to transfer a large amount of data. Routing in WDM networks involves assigning both paths and wavelengths, and is called routing and wavelength assignment (RWA). In WDM optical networks, there are two vital RWA issues that have garnered a lot of interest from researchers as well as network operators. 1) Survivability: Lightpaths in WDM networks usually transport a tremendous amount of data. If a lightpath fails due to various natural or man-made disasters, the data loss can be costly. Hence, survivability, which is the ability to reconfigure and resume communication is indispensable. 2) Impairment-aware routing: As an optical signal traverses its path, it encounters noise and signal distortions along its way. These physical impairments cause bit errors, which may make the signal unrecognizable at the receiving end. In order to reverse the effect of physical impairments, the signal needs to be regenerated at intermediate nodes. Unlike traditional RWA, impairment-aware RWA, takes into account the effect of physical impairments. Impairment-aware RWA entails two important issues: a) Impairment-aware path selection: how to find a feasible path from the source to the destination node? b) Regenerators placement: how many regenerators are required and where to place them in the network? The main focus of this thesis is to study various problems associated with survivability and impairment-aware RWA both in intra-domain (i.e., within in a single domain) and inter-domain (i.e., across domains) WDM networks. Especially, for intra-domain networks, it makes a detailed study of survivable and impairment-aware RWA issues, separately or combined. For the various problems studied in this thesis, the complexity of the problems is analyzed in detail, and accordingly exact, approximation or heuristic algorithms are proposed for solving them. In addition, a case study of survivable and impairment-aware routing is made on a realistic network that connects research and educational institutes in the Netherlands using data obtained from the network. The work done in this thesis will not only help us gain insight into the various problems in WDM networks, but it may also be applicable to corresponding problems in other types of networks, or even to problems in other areas.Network Architectures and Services, TelecommunicationsElectrical Engineering, Mathematics and Computer Scienc
Rational deployment of antimalarial drugs in Africa: should first-line combination drugs be reserved for paediatric malaria cases?
No full textArtemisinin-based combination therapy is exerting novel selective pressure upon populations of Plasmodium falciparum across Africa. Levels of resistance to non-artemisinin partner drugs differ among parasite populations, and so the artemisinins are not uniformly protected from developing resistance, already present in South East Asia. Here, we consider strategies for prolonging the period of high level efficacy of combination therapy for two particular endemicities common in Africa. Under high intensity transmission, two alternating first-line combinations, ideally with antagonistic selective effects on the parasite genome, are advocated for paediatric malaria cases. This leaves second-line and other therapies for adult cases, and for intermittent preventive therapy. The drug portfolio would be selected to protect the 'premier' combination regimen from selection for resistance, while maximising impact on severe disease and mortality in children. In endemic areas subject to low, seasonal transmission of Plasmodium falciparum, such a strategy may deliver little benefit, as children represent a minority of cases. Nevertheless, the deployment of other drug-based interventions in low transmission and highly seasonal areas, such as mass drug administration aimed to interrupt malaria transmission, or intermittent preventive therapy, does provide an opportunity to diversify drug pressure. We thus propose an integrated approach to drug deployment, which minimises direct selective pressure on parasite populations from any one drug component. This approach is suitable for qualitatively and quantitatively different burdens of malaria, and should be supported by a programme of routine surveillance for emerging resistanc
Department of Error: Mapping geographical inequalities in childhood diarrhoeal morbidity and mortality in low-income and middle-income countries, 2000–17: analysis for the Global Burden of Disease Study 2017 (The Lancet (2020) 395(10239) (1779–1801), (S0140673620301148), (10.1016/S0140-6736(20)30114-8))
No full textReiner RC Jr, Hay SI. Mapping geographical inequalities in childhood diarrhoeal morbidity and mortality in low-income and middle-income countries, 2000–17: analysis for the Global Burden of Disease Study 2017. Lancet 2020; 395: 1779–801—In this Article, the author byline has been amended to Local Burden of Disease Diarrhoea Collaborators. This correction has been made to the online version as of June 4, 2020, and the printed version is correct.</p
The Islamist movement in Sudan : the impact of Dr Hassal al-Turabi's personality on the movement.
No full textSIGLEAvailable from British Library Document Supply Centre-DSC:DX201005 / BLDSC - British Library Document Supply CentreGBUnited Kingdo
Author Correction: Mapping local patterns of childhood overweight and wasting in low- and middle-income countries between 2000 and 2017 (Nature Medicine, (2020), 26, 5, (750-759), 10.1038/s41591-020-0807-6)
No full textAn amendment to this paper has been published and can be accessed via a link at the top of the paper.</p
The regulation of labour and the state in the Sudan : a study of the relationship between the stage of social and economic development and the autonomy of labour relations law
No full textThe thesis is a study of labour regulation and the State in the
Sudan in the light of a general theoretical conception of labour law and
the State. The first Chapter defines the concepts of analysis that are
used throughout the study, isolates the "essential" properties of the
Capitalist State and Law from the historically concrete forms which they
assume in a particular society and distinguishes between processes which
influence development of the form of law and others which influence its
sociological development. Drawing on the analysis in Chapter I, Chapter
II exposes the inter-relationship between the Sudanese social formation,
State and Law and the implication of this inter-relationship for both the
form and substance of labour relations law. Chapters III, IV and V are
specific verifications of the hypothesis regarding the inter-relationship
between the State and labour relations law in the Sudan and that
regarding the development of the "substance" and "ideology" of law in
general.
The thesis considers law as an empirically-founded discipline.
But, it distinguishes between various types of empirical facts about law
corresponding with respective semi-autonomous social levels at which law
asserts its existence. The research method followed describes the
empirical facts about law at the particular level and, in order to
determine the epistemological significance of these facts, analytically
relates them to empirical facts at other levels. Wherever used in the
thesis the term "theory" signifies either this methodological procedure of
analysing the inter-connection of empirical facts at a certain level and
their inter-relation with other facts at other levels, or the substantive
generalizations about law which findings at these various levels would
allow.
I consider my application of this methodology to the study of
labour rela tions law, the historical dimension this application introduces
in socio-economic analysis of this law, the criticism of certain Marxist
and other sociological conceptions of law it enables, and the
socio-histor ical relativity of the "substance" and "ideology" of law it
reveals as original contributions to the knowledge of labour law. The
compilation and evaluation within the framework of the thesis of
empirical materials on industrial relations in the Sudan are likewise
original contribution to the knowledge of Sudanese "labour law" and
labour law in general
Tobacco use and cessation counseling in a population of health professions students in South Africa
No full textIncludes bibliographical references.Tobacco is a leading risk factor for the global burden of disease in both developed and developing countries. The morbidity and mortality caused by tobacco can be prevented efficaciously and cost-effectively by active intervention from health professionals. In developing countries, a limited number of studies have explored tobacco usage and training in smoking cessation and prevention amongst health professions students. This pilot study evaluated: 1. tobacco use patterns; 2. knowledge, attitudes and beliefs towards tobacco use and tobacco control; 3. environmental tobacco smoke exposures; and 4. training in smoking cessation and prevention amongst health professions students in South Africa
Global, regional, and national burden of meningitis, 1990-2016: a systematic analysis for the Global Burden of Disease Study 2016
No full textBackground Acute meningitis has a high case-fatality rate and survivors can have severe lifelong disability. We aimed to provide a comprehensive assessment of the levels and trends of global meningitis burden that could help to guide introduction, continuation, and ongoing development of vaccines and treatment programmes. Methods The Global Burden of Diseases, Injuries, and Risk Factors (GBD) 2016 study estimated meningitis burden due to one of four types of cause: pneumococcal, meningococcal, Haemophilus influenzae type b, and a residual category of other causes. Cause-specific mortality estimates were generated via cause of death ensemble modelling of vital registration and verbal autopsy data that were subject to standardised data processing algorithms. Deaths were multiplied by the GBD standard life expectancy at age of death to estimate years of life lost, the mortality component of disability-adjusted life-years (DALYs). A systematic analysis of relevant publications and hospital and daims data was used to estimate meningitis incidence via a Bayesian meta-regression tool. Meningitis deaths and cases were split between causes with meta-regressions of aetiological proportions of mortality and incidence, respectively. Probabilities of long-term impairment by cause of meningitis were applied to survivors and used to estimate years of life lived with disability (YLDs). We assessed the relationship between burden metrics and Socio-demographic Index (SDI), a composite measure of development based on fertility, income, and education. Findings Global meningitis deaths decreased by 21.0% from 1990 to 2016, from 403 012 (95% uncertainty interval [UI] 319426-458 514) to 318 400 (265 218-408 705). Incident cases globally increased from 2.50 million (95% UI 2.19-2.91) in 1990 to 2.82 million (2.46-3.31) in 2016. Meningitis mortality and incidence were dosely related to SDI. The highest mortality rates and incidence rates were found in the peri-Sahelian countries that comprise the African meningitis belt, with six of the ten countries with the largest number of cases and deaths being located within this region. Haemophilus influenzae type b was the most common cause of incident meningitis in 1990, at 780 070 cases (95% UI 613 585-978 219) globally, but decreased the most (-494%) to become the least common cause in 2016, with 397 297 cases (291076-533 662). Meningococcus was the leading cause of meningitis mortality in 1990 (192833 deaths [95% UI 153 358-221 503] globally), whereas other meningitis was the leading cause for both deaths (136 423 [112 682-178 022]) and incident cases (1.25 million [1.06-1.49]) in 2016. Pneumococcus caused the largest number of YLDs (634458 [444 787-839 749]) in 2016, owing to its more severe long-term effects on survivors. Globally in 2016, 1.48 million (1.04-1.96) YLDs were due to meningitis compared with 21.87 million (18.20-28.28) DALYs, indicating that the contribution of mortality to meningitis burden is far greater than the contribution of disabling outcomes. Interpretation Meningitis burden remains high and progress lags substantially behind that of other vaccine-preventable diseases. Particular attention should be given to developing vaccines with broader coverage against the causes of meningitis, making these vaccines affordable in the most affected countries, improving vaccine uptake, improving access to low-cost diagnostics and therapeutics, and improving support for disabled survivors. Substantial uncertainty remains around pathogenic causes and risk factors for meningitis. Ongoing, active cause-specific surveillance of meningitis is crucial to continue and to improve monitoring of meningitis burdens and trends throughout the world. Copyright (C) The Author(s). Published by Elsevier Ltd
