Channel Aided Interference Alignment

Interference alignment (IA) techniques mostly attain their degrees of freedom (DoF) benefits as the number of channel extensions tends to infinity. Intuitively, the more interfering signals that need to be aligned, the larger the number of dimensions needed to align them. This requirement poses a major challenge for IA in practical systems. This work evaluates the necessary and sufficient conditions on channel structure of a fully connected interference network with time-varying fading to make perfect IA feasible within limited number of channel extensions. We propose a method based on the obtained conditions on the channel structure to achieve perfect IA. For the case of $3$ user interference channel, it is shown that only one condition on channel coefficients is required to make perfect IA feasible at all receivers. IA feasibility literature have mainly focused on network topology so far. In contrast, derived channel aiding conditions in this work can be considered as the perfect IA feasibility conditions on channel structure.Comment: 20 pages, 4 figure. arXiv admin note: text overlap with arXiv:0901.4379 by other author

Sufism, Power Politics, and Reform: Al-Rānīrī’s Opposition to Hamzah al-Fanṣūrī’s Teachings Reconsidered

Middle of the seventeenth century witnessed the horror of the Acehnese socio-religious life can not be imagined. These events commonly known as a fatwa banning religious follower of the teachings attributed to great figures Fansuri Hamzah. The books are used as a handle follower Hamzah collected by royal officials, stacked and burned in public. The followers themselves must bear the violence the authorities, because of being chased and forced to 'convert' to no longer follow the belief that later became known as followers of Wujudiyah.DOI: 10.15408/sdi.v4i1.78

The biology and culture of mussels of the genus Perna

This review covers the biology and ecology of the three genera of Perna: P. viridis, P. canaliculatus and P. perna. An overview is given of the technological status of culture systems with emphasis being laid on the description of advanced culture techniques such as raft and longline systems. Postharvest handling aspects for preservation of live and processed mussels are presented in detail and public health and economic aspects of the mussel culture industry are described.Mussel culture, Biology Perna

Dynamite fishing in Sierra Leone

The dynamite fishing operations in Sierra Leone are enumerated and discussed

Dynamite fishing in Sierra Leone

Explosive fishing, Sierra Leone,

Men's Health Week in Iran; the Discrepancy between Experts and the General Population for Educational Priorities

Introduction: With the obsoletion of the paternalistic model of the doctor-patient relationship, considering public opinion regarding healthcare policymaking seems to be of great necessity. The present study was conducted to determine the educational priorities of male urology specialists and the general male population concerning urological diseases. Materials and methods: In this cross-sectional survey study, 400 male urologists and 400 men from the general population were assessed. Our investigation was carried out using a seven-item questionnaire covering the most important urological conditions. Respondents gathered from all over Iran through the 22nd Congress of Iranian Urological Association (IUA) and street surveys. Results: The mean age of the participants was 40.69 ± 13.23. The mean age for the general population and urologists was 35.8 ± 13.7 and 45.6 ± 10.6 years, respectively (P=0.0001). 56.8% of the respondents from the general population had a university degree. Overall, erectile dysfunction and sexually transmitted diseases (STDs) were the most mentioned diseases as an educational priority (40.1%). Chronic prostatitis was also the least mentioned condition as an educational priority in both groups and overall among all the participants ‎ (20.9%). A significant difference was observed between the general population and urologists in all the examined conditions (P<0.05).  Conclusion: This study indicated the differences among the educational priorities of the general male population and male urologists, and the necessity to make these two points of view closer and to involve the opinion of general population in decision making for men’s health week educational topics. &nbsp

Solar systems and computers: how to become independent of electricity supply

Solar power, Computers

European Union supports project to strengthen fisheries and biodiversity management in African, Caribbean, and Pacific (ACP) countries

Proper resource management implies a better understanding of ecosystems and the conservation of biodiversity. Scientists from developing countries often have limited information on their aquatic resources because of many difficulties in accessing and exchanging information on a national and international level. The project described not only aims to strengthen the scientific capacity of fisheries scientists in ACP institutions but it is also expected to create an awareness among fisheries researchers and managers of the importance of conserving biodiversity for the sustainable use of living aquatic resources. This will be achieved through training, building a network of regional and transregional cooperation using modern communication facilities, the promotion of research and the distribution and improvement of fisheries management tools. It is hoped that these capabilities will enable fisheries scientists in ACP countries to actively contribute towards a discussion to solve common problems originating from the endangering of the ecological basis of their fisheries

Fishing down Canadian aquatic food webs

The mean trophic level (TL) of fish landed in fisheries on the east and west coasts of Canada is declining by 0.03–0.10·decade–1, similar to global trends. This finding is based on data from United Nations Food and Agriculture Organization and the Canadian Department of Fisheries and Oceans and other Canadian sources for the period 1873–1997. Significant rates of decline in mean TL were obtained even when key species — Atlantic cod (Gadus morhua) on the east coast and Pacific herring (Clupea pallasi) and Pacific hake (Merluccius productus) on the west coast — were omitted from the analysis. Fish taken in inland water fisheries did not exhibit a decline in mean TL. Two models were developed, based on length and age, respectively, for correcting TL estimates of individual species for the effects of changes in body size due to changes in fishing mortality. Both produced corrections that were small relative to changes in mean TL that resulted from changes in species composition of the catch over time. Overall, these results suggest that the mean TL of fish landed can be used as an index of sustainability in ultispecies fisheries and that its reliability will depend on the quality of the data and length of the time series available for analysis