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

Spectrum sensing in cognitive radio using multitaper method based on MIMO-OFDM techniques

The current inefficient utilization of frequency spectrum has alerted regulatory bodies to streamline improvements. Cognitive radio (CR) has recently received considerable attention and is widely perceived as a promising improvement tool in estimating, or equivalently sensing, the frequency spectrum for wireless communication systems. The cognitive cycle in CR systems is capable of recognizing and processing better spectrum estimation (SE) and hence promotes the efficiency of spectrum utilization. Among different SE methods, the multi-taper method (MTM) shows encouraging results. Further performance improvement in the SE for CR can be achieved by applying multiple antennas and combining techniques. This paper proposes a constructive development of SE using MTM, abbreviated as MTSE, and by employing multiple-input multiple-output (MIMO), parsed into separate parallel channels using singular value decomposition (SVD), and maximum ratio combining (MRC) configurations. Deviating from these improvements, however, multicarrier systems such as orthogonal frequency division multiplexing (OFDM) show inferior sensing performances due to the noise multiplicity generated and combined from all subcarrier channels. By means of the quadrature matrix form, the probabilities for such integrated settings of SE have been derived to reach at their approximate asymptotes. Numerical simulations revealed specific better performances stemmed from coupling the fashionable MTSE and MIMO technologies

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

Impact of primary kidney disease on the effects of empagliflozin in patients with chronic kidney disease: secondary analyses of the EMPA-KIDNEY trial

Background: The EMPA KIDNEY trial showed that empagliflozin reduced the risk of the primary composite outcome of kidney disease progression or cardiovascular death in patients with chronic kidney disease mainly through slowing progression. We aimed to assess how effects of empagliflozin might differ by primary kidney disease across its broad population. Methods: EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA). Patients were eligible if their estimated glomerular filtration rate (eGFR) was 20 to less than 45 mL/min per 1·73 m2, or 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher at screening. They were randomly assigned (1:1) to 10 mg oral empagliflozin once daily or matching placebo. Effects on kidney disease progression (defined as a sustained ≥40% eGFR decline from randomisation, end-stage kidney disease, a sustained eGFR below 10 mL/min per 1·73 m2, or death from kidney failure) were assessed using prespecified Cox models, and eGFR slope analyses used shared parameter models. Subgroup comparisons were performed by including relevant interaction terms in models. EMPA-KIDNEY is registered with ClinicalTrials.gov, NCT03594110. Findings: Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and followed up for a median of 2·0 years (IQR 1·5–2·4). Prespecified subgroupings by primary kidney disease included 2057 (31·1%) participants with diabetic kidney disease, 1669 (25·3%) with glomerular disease, 1445 (21·9%) with hypertensive or renovascular disease, and 1438 (21·8%) with other or unknown causes. Kidney disease progression occurred in 384 (11·6%) of 3304 patients in the empagliflozin group and 504 (15·2%) of 3305 patients in the placebo group (hazard ratio 0·71 [95% CI 0·62–0·81]), with no evidence that the relative effect size varied significantly by primary kidney disease (pheterogeneity=0·62). The between-group difference in chronic eGFR slopes (ie, from 2 months to final follow-up) was 1·37 mL/min per 1·73 m2 per year (95% CI 1·16–1·59), representing a 50% (42–58) reduction in the rate of chronic eGFR decline. This relative effect of empagliflozin on chronic eGFR slope was similar in analyses by different primary kidney diseases, including in explorations by type of glomerular disease and diabetes (p values for heterogeneity all >0·1). Interpretation: In a broad range of patients with chronic kidney disease at risk of progression, including a wide range of non-diabetic causes of chronic kidney disease, empagliflozin reduced risk of kidney disease progression. Relative effect sizes were broadly similar irrespective of the cause of primary kidney disease, suggesting that SGLT2 inhibitors should be part of a standard of care to minimise risk of kidney failure in chronic kidney disease. Funding: Boehringer Ingelheim, Eli Lilly, and UK Medical Research Council

Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries

Background: Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.Methods: This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.Results: The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P < 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (beta coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.Conclusion: Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely

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