Debating Africa : BBC's documentary "Heart & soul - return to Zanzibar"

This issue of ISJ carried another article in the irregular series "Debating and Documenting Africa", the first one having been published in volume 1, number 2 (June 2008). This issue carries a discussion between Katy Hickman, Senior Producer at BBC World Service Religion and Ethics and Prof. Abdul Sheriff, formerly Professor of History at the University of Dar es Salaam and Director of Zanzibar Museums and the author of forthcoming titles, Dhow Cultures of the Indian Ocean: Cosmopolitanism, Commerce and Islam and The Early Dhow Culture in the Indian Ocean: From the Periplus to the Portuguese. The context of this debate is BBC Radio’s "Return to Zanzibar" programme in their series, Heart & Soul. Setting the scene is Katy Hickman’s contact with Prof. Sheriff in which she enclosed an early outline of the programme. This is followed by Prof. Sheriff’s response which raises various key issue of relevance to the study of Africa. This is followed by Katy Hickman’s response which explains how the final version was influenced by points raised by Prof. Sheriff. Also included is a later piece by the presenter of the programme, Yasmin Alibhai-Brown. While not part of this discussion, the latter is included to provide the presenter’s perspective. All these provide a look behind the scene on debates that take place before programmes are made and bring out the key role that historians, researchers and academicians can, and need to play, in social communications. ISJ’s Editorial Board re-presents this debate to stimulate further discussion

The value of information in organisations: A study of information use situations as contexts of value.

The notion that the value of information is significantly dependent on the context of use is widely accepted in information systems research. Context is however often conceived as given and exogenous to the use activity and hence beyond the control of the user. This study takes a dynamic and holistic view of context in which the purposes, processes and effects of information use are seen as inextricable from the structural and environmental factors that mediate such use in organisations. The concept of Information Use Situation (lUS) is employed to represent this view of context. An lUS framework is developed and used as a guide to explore, describe, and interpret a number of information use situations in four organisations in the service sector. The study draws on several context studies in information systems, work motivation and self-interest theories in social psychology, and a number of philosophical propositions on the nature of information and value, in highlighting the key features of the situations studied. The findings suggest that, in general, information use situations affect the value-in-use of information in at least three ways, by acting as filters, as mediators of use behaviour and as frames of reference for evaluating informational activities. The main contribution of this thesis to information systems research is in proposing and exploring the concept of information use situation as a more holistic view of context when studying the value of information in organisation. The thesis concludes that organisations need to recognise the diversity of information use situations they feature and to appreciate that the value of information depends significantly on the nature of the situation in which it is used. This requires managers to pay as much attention to the processes by which employees experience and appropriate information as to the quality of the formal information used if they are to realise the optimum value of their information resources

The rise of a commercial empire: An aspect of the economic history of Zanzibar, 1770-1873.

The development of Zanzibar as an entrepot and capital of a vast commercial empire has previously been attributed entirely to the far-sighted policies of Seyyid Said. A re-examination of the economic history of East Africa reveals that economic expansion from the eighteenth century resulted from economic forces which were independent of Omani policies; that these forces were already in motion before Seyyid Said first visited Zanzibar; and that the Omanis manipulated these forces to centralise economic activities at Zanzibar to a greater degree than would otherwise have been achieved, thus forming a commercial empire. The Omani demand for slaves for their expanding date plantations and the increasing French demand in the Mascarenes initiated a rapid expansion of Kilwa's hinterland and the growth of Zanzibar's entrepot role to supply the imports. When the French slave trade suffered a mortal blow from the Napoleonic wars and the eventual prohibition in 1822, the redundant slaves were diverted to the clove plantations of Zanzibar. The second major development was initiated by Portuguese taxation of the ivory trade of Mozambique. By 1801 ivory exports had been halved. To supply the unsatisfied Indian demand, to which was soon to be added European and American demand, the northern ivory hinterland was rapidly expanded during the first quarter of the nineteenth century. The development of the Indian mercantile community facilitated this expansion. The supply of this commodity of the hunt called for a constant expansion of the hinterland and sophistication of the commercial organization which, however, was dependent entirely on a caravan of human shoulders. The demand thus regularly outstripped supply, and ivory prices consequently rose. The price of manufactured imports, on the other hand, tended to remain steady or even decline as a result of mechanisation. The diverging price curves thus constituted a dynamic force for economic expansion. On such a vibrant economic base the Omanis structured their commercial empire. The empire, however, was not built on a stable administrative or political structure, but on a system of influence and common economic interests. In the age of the "Scramble" it merely crumbled

Automatic modulation classification using interacting multiple model - Kalman filter for channel estimation

YesA rigorous model for automatic modulation classification (AMC) in cognitive radio (CR) systems is proposed in this paper. This is achieved by exploiting the Kalman filter (KF) integrated with an adaptive interacting multiple model (IMM) for resilient estimation of the channel state information (CSI). A novel approach is proposed, in adding up the squareroot singular values (SRSV) of the decomposed channel using the singular value decompositions (SVD) algorithm. This new scheme, termed Frobenius eigenmode transmission (FET), is chiefly intended to maintain the total power of all individual effective eigenmodes, as opposed to keeping only the dominant one. The analysis is applied over multiple-input multiple-output (MIMO) antennas in combination with a Rayleigh fading channel using a quasi likelihood ratio test (QLRT) algorithm for AMC. The expectation-maximization (EM) is employed for recursive computation of the underlying estimation and classification algorithms. Novel simulations demonstrate the advantages of the combined IMM-KF structure when compared to the perfectly known channel and maximum likelihood estimate (MLE), in terms of achieving the targeted optimal performance with the desirable benefit of less computational complexity loads

Novel Approach for Modeling Wireless Fading Channels using a Finite State Markov Chain

yesEmpirical modeling of wireless fading channels using common schemes such as autoregression and thefinitestate Markov chain (FSMC) is investigated. The conceptual background of both channel structures and the establishment of their mutual dependence in a confined manner are presented. The novel contribution lies in the proposal of a new approach for deriving the state transition probabilities borrowed from economic disciplines, which has not been studied so far with respect to the modeling of FSMC wireless fading channels. The proposed approach is based on equal portioning of the received signal-to-noise ratio, realized by using an alternative probability construction that was initially highlighted by Tauchen. The associated statistical procedure shows that afirst-order FSMC with a limited number of channel states can satisfactorily approximate fading. The computational overheads of the proposed technique are analyzed andproven to be less demanding compared to the conventional FSMC approach based on the levelcrossing rate. Simulations confirm the analytical results and promising performance of the new channel modelbased on the Tauchen approach without extracomplexity costs

Effects of hospital facilities on patient outcomes after cancer surgery: an international, prospective, observational study

Background Early death after cancer surgery is higher in low-income and middle-income countries (LMICs) compared with in high-income countries, yet the impact of facility characteristics on early postoperative outcomes is unknown. The aim of this study was to examine the association between hospital infrastructure, resource availability, and processes on early outcomes after cancer surgery worldwide.Methods A multimethods analysis was performed as part of the GlobalSurg 3 study-a multicentre, international, prospective cohort study of patients who had surgery for breast, colorectal, or gastric cancer. The primary outcomes were 30-day mortality and 30-day major complication rates. Potentially beneficial hospital facilities were identified by variable selection to select those associated with 30-day mortality. Adjusted outcomes were determined using generalised estimating equations to account for patient characteristics and country-income group, with population stratification by hospital.Findings Between April 1, 2018, and April 23, 2019, facility-level data were collected for 9685 patients across 238 hospitals in 66 countries (91 hospitals in 20 high-income countries; 57 hospitals in 19 upper-middle-income countries; and 90 hospitals in 27 low-income to lower-middle-income countries). The availability of five hospital facilities was inversely associated with mortality: ultrasound, CT scanner, critical care unit, opioid analgesia, and oncologist. After adjustment for case-mix and country income group, hospitals with three or fewer of these facilities (62 hospitals, 1294 patients) had higher mortality compared with those with four or five (adjusted odds ratio [OR] 3.85 [95% CI 2.58-5.75]; p<0.0001), with excess mortality predominantly explained by a limited capacity to rescue following the development of major complications (63.0% vs 82.7%; OR 0.35 [0.23-0.53]; p<0.0001). Across LMICs, improvements in hospital facilities would prevent one to three deaths for every 100 patients undergoing surgery for cancer.Interpretation Hospitals with higher levels of infrastructure and resources have better outcomes after cancer surgery, independent of country income. Without urgent strengthening of hospital infrastructure and resources, the reductions in cancer-associated mortality associated with improved access will not be realised

The Longue Durée in Socio-Cultural Integration in the Western Indian Ocean

Mitschnitt eines Vortrags, der am 24.06.2003 im Rahmen des Sozial- und Kulturwissenschaftlichen Forschungskolloquiums am Südasien-Institut der Universität Heidelberg gehalten wurde