Swedish Defence Research Agency

About: Swedish Defence Research Agency is a government organization based out in Stockholm, Sweden. It is known for research contribution in the topics: Radar & Laser. The organization has 1413 authors who have published 2731 publications receiving 56083 citations. The organization is also known as: Totalförsvarets forskningsinstitut.

Relation between the amplitude probability distribution of an interfering signal and its impact on digital radio receivers

Abstract: New emission limit requirements are needed to protect digital communication systems from radiated interference. Traditionally, standard emission requirements have focused on protecting analog amplitude modulated radio services. However, developments in digital technology require emission limit requirements adapted to protect digital radio communication services. The amplitude probability distribution (APD) of the envelope or the quadrature components of an interfering signal has been shown to be related to the bit error probability of some digital radio receivers. However, a general description of the APD of an interfering signal and its impact on digital coherent radio receivers has not been presented. The aim of this paper is to clarify this relationship for a larger group of digital radio receivers. A method of incorporating the APD in conventional error expressions developed for digital coherent radio receivers in additive white Gaussian noise is presented. Furthermore, the relation between the maximum error probability for different digital modulation schemes and the APD is described, which allows definition of emission requirements on the APD

Outbreaks of Tularemia in a Boreal Forest Region Depends on Mosquito Prevalence

Abstract: Background. We aimed to evaluate the potential association of mosquito prevalence in a boreal forest area with transmission of the bacterial disease tularemia to humans, and model the annual variation of disease using local weather data. Methods. A prediction model for mosquito abundance was built using weather and mosquito catch data. Then a negative binomial regression model based on the predicted mosquito abundance and local weather data was built to predict annual numbers of humans contracting tularemia in Dalarna County, Sweden. Results. Three hundred seventy humans were diagnosed with tularemia between 1981 and 2007, 94% of them during 7 summer outbreaks. Disease transmission was concentrated along rivers in the area. The predicted mosquito abundance was correlated (0.41, P , .05) with the annual number of human cases. The predicted mosquito peaks consistently preceded the median onset time of human tularemia (temporal correlation, 0.76; P , .05). Our final predictive model included 5 environmental variables and identified 6 of the 7 outbreaks. Conclusions. This work suggests that a high prevalence of mosquitoes in late summer is a prerequisite for outbreaks of tularemia in a tularemia-endemic boreal forest area of Sweden and that environmental variables can be used as risk indicators.

Ozone-induced bronchial epithelial cytokine expression differs between healthy and asthmatic subjects.

Abstract: Background Ozone (O3) is a common air pollutant associated with adverse health effects. Asthmatics have been suggested to be a particularly sensitive group. Objective This study evaluated whether b ...

Characterisation of immune responses and protective efficacy in mice after immunisation with Rift Valley Fever virus cDNA constructs

Abstract: Affecting both livestock and humans, Rift Valley Fever is considered as one of the most important viral zoonoses in Africa However, no licensed vaccines or effective treatments are yet available for human use Naked DNA vaccines are an interesting approach since the virus is highly infectious and existing attenuated Rift Valley Fever virus vaccine strains display adverse effects in animal trials In this study, gene-gun immunisations with cDNA encoding structural proteins of the Rift Valley Fever virus were evaluated in mice The induced immune responses were analysed for the ability to protect mice against virus challenge Immunisation with cDNA encoding the nucleocapsid protein induced strong humoral and lymphocyte proliferative immune responses, and virus neutralising antibodies were acquired after vaccination with cDNA encoding the glycoproteins Even though complete protection was not achieved by genetic immunisation, four out of eight, and five out of eight mice vaccinated with cDNA encoding the nucleocapsid protein or the glycoproteins, respectively, displayed no clinical signs of infection after challenge In contrast, all fourteen control animals displayed clinical manifestations of Rift Valley Fever after challenge The appearance of Rift Valley Fever associated clinical signs were significantly decreased among the DNA vaccinated mice and further adjustment of this strategy may result in full protection against Rift Valley Fever