Forecasting overseas visitors into the United Kingdom using continuous time and autoregressive fractional integrated moving average models with discrete data

This paper applies Gaussian estimation methods to continuous time models for modelling overseas visitors into the UK. The use of continuous time modelling is widely used in economics and finance but not in tourism forecasting. Using monthly data for 1986–2010, various continuous time models are estimated and compared to autoregressive integrated moving average (ARIMA) and autoregressive fractionally integrated moving average (ARFIMA) models. Dynamic forecasts are obtained over different periods. The empirical results show that the ARIMA model performs very well, but that the constant elasticity of variance (CEV) continuous time model has the lowest root mean squared error (RMSE) over a short period.

A comparative study: long and short term effect of a nutrition sensitive approach to delay the progression of HIV to AIDS among people living with HIV (PLWH) in Nigeria

Background: Malnutrition has a negative impact on optimal immune function, thus increasing susceptibility to morbidity and mortality among HIV positive patients. Evidence indicates that the prevalence of macro and micronutrient deficiencies (particularly magnesium, selenium, zinc, and vitamin C) has a negative impact on optimal immune function, through the progressive depletion of CD4 T-lymphocyte cells, which thereby increases susceptibility to morbidity and mortality among PLWH. Objective: To assess the short and long term effects of a nutrition sensitive intervention to delay the progression of human immune-deficiency virus (HIV) to AIDS among people living with HIV in Abuja, Nigeria. Methods: A randomized control trial was carried out on 400 PLWH (adult, male and female of different religious background) in Nigeria between January and December 2012. Out of these 400 participants, 100 were randomly selected for the pilot study, which took place over six months (January to June, 2012). The participants in the pilot study overlapped to form part of the scale-up participants (n 400) monitored from June to December 2012. The comparative effect of daily 354.92 kcal/d optimized meals consumed for six and twelve months was ascertained through the nutritional status and biochemical indices of the study participants (n=100 pilot interventions), who were and were not taking the intervention meal. The meal consisted of: Glycine max 50g (Soya bean); Pennisetum americanum 20g (Millet); Moringa oleifera 15g (Moringa); Daucus carota spp. sativa 15g (Carrot). Results: At the end of sixth month intervention, mean CD4 cell count (cell/mm3) for Pre-ART and ART Test groups increased by 6.31% and 12.12% respectively. Mean mid upper arm circumference (MUAC) for Pre-ART and ART Test groups increased by 2.72% and 2.52% within the same period (n 400). Comparatively, participants who overlapped from pilot to scale-up intervention (long term use, n 100) were assessed for 12 months. Mean CD4 cell count (cell/mm3) for Pre-ART and ART test groups increased by 2.21% and 12.14%. Mean MUAC for Pre-ART and ART test groups increased by 2.08% and 3.95% respectively. Moreover, student’s t-test analysis suggests a strong association between the intervention meal, MUAC, and CD4 count on long term use of optimized meal in the group of participants being treated with antiretroviral therapy (ART) (P<0.05). Conclusion: Although the achieved results take the form of specific technology, it suggests that a prolong consumption of the intervention meal will be suitable to sustain the gained improvements in the anthropometric and biochemical indices of PLWHIV in Nigeria.

‘Don’t look down!’: A short history of rooftopping photography

The article examines the practice known as ‘rooftopping photography’ and its significance for the representation of vertical cities. It begins by charting the historical development of architecture as a viewing platform in the age of the camera, and dwells on the imagery of cityscapes from above that emerged in the inter-war period. Against this background, the essay investigates how rooftopping arose out of the urban exploration movement and became a global trend in the early 2010s. This phenomenon is situated within its wider social and cultural context, and is discussed with reference to the online media discourse that contributed to its public visibility. A set of ideas from the philosophy of photography and visual culture inform the critical analysis of rooftopping photographs: this broad and diverse body of images is examined with a focus on two predominant modes of representation—panoramic and plunging views. The affective responses elicited by so-called ‘vertigo-inducing’ images are discussed through the concept of vicarious kinaesthesia, which offers insights into the nexus between visceral experience and visual representation that lies at the core of rooftopping. By unpacking this interplay, the essay explores a phenomenon that has hitherto been given little scholarly attention and reflects on its broader implications for the relationship between photography and architecture today.