A filter synthesis technique applied to the design of multistage broad-band microwave amplifiers

A method for designing multistage broad-band amplifiers based upon well-known filter synthesis techniques is presented. Common all-pole low-pass approximations are used to synthesize prototype amplifier circuits that may be scaled in frequency and impedance. All-pass filters introduced at the first stage are shown to improve input match while maintaining circuit performance less 6 dB gain. A theoretical comparison is made with the distributed amplifier and the cascaded single-stage distributed amplifier. Theoretically, a larger gain-bandwidth product is achieved using the synthesis technique. A proof-of-concept Butterworth low-pass two-stage amplifier was designed, simulated, and measured and achieved a flat gain performance of 1–4 GHz with a power gain of 14.5±1 dB close to the predicted 1–4.2 GHz, 15±1 dB

Gendering the revolution: Bohemia, power and culture in post-revolutionary Cuba, 1960–85

This article presents a gender analysis of power and culture in post-revolutionary Cuba, using Bohemia magazine as a source. It argues that despite the relative paucity of historical research on the subject, gender was integral to the identity, legitimacy and popularity of the Cuban Revolution. This article examines Bohemia as a communicatory tool and a site of dissemination and contestation to demonstrate how the Cuban Revolution both endorsed and criticised the cultural ideals it inherited. Bohemia elucidates a dynamic between grassroots enthusiasm, institutional mobilisation and popular disenchantment, whereby gender discourse functioned to encourage and regulate behaviour. The article first focuses on the construction of national identity through historical narratives in Bohemia, exploring the uses of José Martí and Mariana Grajales to create an ambiguous discourse framing behaviour, both domestically and internationally. It then shifts to the discursive construction of the individual Cuban woman, analysing the multiple contentious identities that existed in this post-revolutionary cultural framework, using this incongruity to evidence fundamental shortcomings in the revolution’s approach. The final section bridges the national and the individual to understand how these discursive frameworks were used to encourage female participation in the workplace, in political organisations and social campaigns. This analysis also highlights that the central dissonance within the revolutionary project’s cultural framework prevented the realisation of gender equality. This article therefore argues that a gender analysis is integral to understanding the nature, legitimacy and longevity of the Cuban Revolution on both a national and international level

Food Limitation as a Potentially Emerging Contributor to the Asian Vulture Crisis

It was believed that the reason for decline in Asian vulture population is the drug, Diclofenac sodium (DFS), used in livestock. Even after declaring the DFS use banned by the government, apparent decrease in the population of vultures was reported. Alternate hypothesis was suggested that food limitation may be a cause of Asian vulture crisis in Pakistan. Very recent shifts in livestock utilization observed in Pakistan may present a significant barrier to vulture recovery. Increased livestock utilization is translated to fewer carcasses. Since 2005, no livestock carcasses were found in 1650 km transect in the habitat of vultures. Carcasses recorded 13 in 1999 gradually declined to almost zero in 2005 and onwards, which suggests DFS may not be the only cause of Asian Vulture Crisi

Enhanced catalytic activity of Ni on η-Al2O3 and ZSM-5 on addition of ceria zirconia for the partial oxidation of methane

peer-reviewedNickel supported on η-Al2O3 and ZSM-5(80) catalysts with and without the addition of ceria-zirconia, were prepared by co-precipitation and wet impregnation methods and used for the low temperature catalytic partial oxidation of methane (CPOM). The catalysts were tested under reaction temperatures of between 400 and 700 °C with a WHSV of 63,000 mL g−1 h−1. The activity of the catalyst was found to be dependent on the support and preparation method. The optimum catalyst composition of those tested was 10% Ni on 25%CeO2-ZrO2/ZSM-5(80), prepared by co-precipitation, where the reaction reached equilibrium conversion at 400 °C (T50% < 400 °C), which is one of the lowest temperatures reported to date. Further increases in temperature led to improved selectivity to CO reaching 60% at 600 °C. Although the observed kinetics were found to be controlled by strong adsorption of CO at lower temperature, this was an equilibrium limitation with longer time on stream experiments showing no decrease in the catalyst activity over 25 h at 400 °CACCEPTEDpeer-reviewe

How much is '5-a-day'? A qualitative investigation into consumer understanding of fruit and vegetable intake guidelines.

BACKGROUND: Despite the known health benefits of fruit and vegetables (FV), population intakes remain low. One potential contributing factor may be a lack of understanding surrounding recommended intakes. The present study aimed to explore the understanding of FV intake guidelines among a sample of low FV consumers. METHODS: Six semi-structured focus groups were held with low FV consumers (n = 28, age range 19-55 years). Focus groups were recorded digitally, transcribed verbatim and analysed thematically using nvivo (QSR International, Melbourne, Australia) to manage the coded data. Participants also completed a short questionnaire assessing knowledge on FV intake guidelines. Descriptive statistics were used to analyse responses. RESULTS: The discussions highlighted that, although participants were aware of FV intake guidelines, they lacked clarity with regard to the meaning of the '5-a-day' message, including what foods are included in the guideline, as well as what constitutes a portion of FV. There was also a sense of confusion surrounding the concept of achieving variety with regard to FV intake. The sample highlighted a lack of previous education on FV portion sizes and put forward suggestions for improving knowledge, including increased information on food packaging and through health campaigns. Questionnaire findings were generally congruent with the qualitative findings, showing high awareness of the '5-a-day' message but a lack of knowledge surrounding FV portion sizes. CONCLUSIONS: Future public health campaigns should consider how best to address the gaps in knowledge identified in the present study, and incorporate evaluations that will allow the impact of future initiatives on knowledge, and ultimately behaviour, to be investigated