Mobile Audiovisual Terminal: System Design and Subjective Testing in DECT and UMTS networks

It is anticipated that there will shortly be a requirement for multimedia terminals that operate via mobile communications systems. This paper presents a functional specification for such a terminal operating at 32 kb/s in a digital European cordless telecommunications (DECT) and universal mobile telecommunications system (UMTS) radio network. A terminal has been built, based on a PC with digital signal processor (DSP) boards for audio and video coding and decoding. Speech coding is by a phonetically driven code-excited linear prediction (CELP) speech coder and video coding by a block-oriented hybrid discrete cosine transform (DCT) coder. Separate channel coding is provided for the audio and video data. The paper describes the techniques used for audio and video coding, channel coding, and synchronization. Methods of subjective testing in a DECT network and in a UMTS network are also described. These consisted of subjective tests of first impressions of the mobile audio–visual terminal (MAVT) quality, interactive tests, and the completion of an exit questionnaire. The test results showed that the quality of the audio was sufficiently good for comprehension and the video was sufficiently good for following and repeating simple mechanical tasks. However, the quality of the MAVT was not good enough for general use where high-quality audio and video was needed, especially when transmission was in a noisy radio environment

Perfect design or practical study? A workshop on navigating the challenges of community based prevention research

Subject: There is a shared interest among public health researchers in tackling methodological issues surrounding community based research, and on moving beyond a focus on individual level change. As part of a project on community empowerment funded by the People’s Health Trust, we have conducted a feasibility study on quantitative and economic evaluation of complex community-based interventions. To understand different quantitative methods that can be used to evaluate community empowerment interventions, we have undertaken a methodological literature review that identified the following sets of challenges: Defining population of interest – interventions taking place at a community level are not specifically targeted at a well-defined group of individuals. Therefore it is challenging to even find those who are affected by an intervention. Diverse and un-prescribed effects – the effect of community empowerment interventions are likely broad, suggesting we need to measure multiple outcomes in order to detect change. This increases the likelihood of detecting spurious change and can require a lot of resource. Furthermore, in many cases these outcomes are not pre-defined by a programme (i.e. communities choose their own foci)

Flash sintering of beta-alumina solid electrolytes for sodium battery applications

The rechargeable sodium batteries, sodium sulphur (NaS) batteries and molten-salt sodium nickel chloride (Na-NiCl2) are proven commercially available systems, particularly for large-scale energy storage applications and electric vehicle applications respectively. They have attractive properties such as the use of abundant low-cost raw materials, high energy and power density, high faradaic efficiency of charge/discharge, zero self-discharge rate and proven long-term durability. Conventional manufacturing of the core component, the sodium beta”-alumina solid electrolyte, requires a high sintering temperatures, ~ 1600 °C to achieve high density and good ceramic quality, which contributes significantly to battery cost, energy and time consumption in production. Flash sintering, a novel low-cost electrical field-assisted sintering technology, has been investigated for sintering beta”-alumina samples in a collaboration between Lucideon Limited and Ionotec Limited. This work will describe the preliminary results on flash sintering equipment design and prototype sodium beta”-alumina ceramics with variation of the flash-sintering process parameters, i.e. current, frequency, times (incubation, development, holding), pulse experiments, current ramp rate, the on-set furnace temperature, sample geometry (discs versus open-ended tubes), electrode materials (Ag versus Pt paints), single versus double electrode and sample homogeneity. In particular, we will report a significant step towards scale up by showing results on homogeneously-sintered, highly dense more complex geometries such as tubes and closed end tubes using refined field sintering process

Investment Evaluation of a Suburban Coastal Transport System

This paper aims at determining the optimum viable solution of an investment on a suburban coastal shipping system in the area of Athens. More specifically the development of a sea transport system, alternative to the existing road one, that connects Piraeus with the southern suburban coastal area of Athens is examined. The best viable solution of such an undertaking is considered to be the one, which under the existing constraints maximises the total profit that derives from this investment. The variables used for the formation of the constraints are the number of vessels used, the routing and the price of the services. The article focuses on the financing alternatives of the project and their impact on its economic efficiency and concludes with the best viable scenarios and optimum solution

A labelled discrete choice experiment adds realism to the choices presented: preferences for surveillance tests for Barrett esophagus

<p>Abstract</p> <p>Background</p> <p>Discrete choice experiments (DCEs) allow systematic assessment of preferences by asking respondents to choose between scenarios. We conducted a labelled discrete choice experiment with realistic choices to investigate patients' trade-offs between the expected health gains and the burden of testing in surveillance of Barrett esophagus (BE).</p> <p>Methods</p> <p>Fifteen choice scenarios were selected based on 2 attributes: 1) type of test (endoscopy and two less burdensome fictitious tests), 2) frequency of surveillance. Each test-frequency combination was associated with its own realistic decrease in risk of dying from esophageal adenocarcinoma. A conditional logit model was fitted.</p> <p>Results</p> <p>Of 297 eligible patients (155 BE and 142 with non-specific upper GI symptoms), 247 completed the questionnaire (84%). Patients preferred surveillance to no surveillance. Current surveillance schemes of once every 1–2 years were amongst the most preferred alternatives. Higher health gains were preferred over those with lower health gains, except when test frequencies exceeded once a year. For similar health gains, patients preferred video-capsule over saliva swab and least preferred endoscopy.</p> <p>Conclusion</p> <p>This first example of a labelled DCE using realistic scenarios in a healthcare context shows that such experiments are feasible. A comparison of labelled and unlabelled designs taking into account setting and research question is recommended.</p

Differential trends in the rising incidence of endometrial cancer by type: data from a UK population-based registry from 1994 to 2006

BACKGROUND: Endometrial cancer is the most common gynaecological cancer in the western world, the incidence increasing in the United Kingdom by over 40 % since 1993. Two types of endometrial cancer exist – oestrogen-dependent type 1 with good prognosis and non-oestrogen-dependent type 2 with poor prognosis. The histopathological distribution of the increase in endometrial cancer is unknown. This study investigates the observed incidence trends of the two types, the age, stage, and socioeconomic distribution of this increase and survival outcome. METHODS: Data were analysed from 6867 women with endometrial cancer registered between 1994 and 2006, at a UK population-based cancer registry. RESULTS: Increased endometrial cancer incidence is confined to type 1 cancers with a significant increase in age standardised incidenc

Important marine areas for the conservation of northern rockhopper penguins within the Tristan da Cunha Exclusive Economic Zone

The designation of Marine Protected Areas has become an important approach to conserving marine ecosystems that relies on robust information on the spatial distribution of biodiversity. We used GPS tracking data to identify marine Important Bird and Biodiversity Areas (IBAs) for the endangered northern rockhopper penguin Eudyptes moseleyi within the Exclusive Economic Zone (EEZ) of Tristan da Cunha in the South Atlantic. Penguins were tracked throughout their breeding season from 3 of the 4 main islands in the Tristan da Cunha group. Foraging trips remained largely within the EEZ, with the exception of those from Gough Island during the incubation stage. We found substantial variability in trip duration and foraging range among breeding stages and islands, consistent use of areas among years and spatial segregation of the areas used by neighbouring islands. For colonies with no or insufficient tracking data, we defined marine IBAs based on the mean maximum foraging range and merged the areas identified to propose IBAs around the Tristan da Cunha archipelago and Gough Island. The 2 proposed marine IBAs encompass 2% of Tristan da Cunha’s EEZ, and are used by all northern rockhopper penguins breeding in the Tristan da Cunha group, representing ~90% of the global population. Currently, the main threat to northern rockhopper penguins within the Tristan da Cunha EEZ is marine pollution from shipping, and the risk of this would be reduced by declaring waters within 50 nautical miles of the coast as ‘Areas To Be Avoided