An implementation of a reference symbol approach to generic modulation in fading channels

As mobile satellite communications systems evolve over the next decade, they will have to adapt to a changing tradeoff between bandwidth and power. This paper presents a flexible approach to digital modulation and coding that will accommodate both wideband and narrowband schemes. This architecture could be the basis for a family of modems, each satisfying a specific power and bandwidth constraint, yet all having a large number of common signal processing blocks. The implementation of this generic approach, with general purpose digital processors for transmission of 4.8 kilobits per sec. digitally encoded speech, is described

Using formative assessment to influence self- and co-regulated learning: the role of evaluative judgement

Recently, the concept of evaluative judgement has gained attention as a pedagogical approach to classroom formative assessment practices. Evaluative judgement is the capacity to be able to judge the work of oneself and that of others, which implies developing knowledge about one’s own assessment capability. A focus on evaluative judgement helps us to better understand what is the influence of assessment practices in the regulation of learning. In this paper, we link evaluative judgement to two self-regulated learning models (Zimmerman and Winne) and present a model on the effects on co-regulation of learning. The models help us to understand how students can be self-regulated through developing their evaluative judgement. The co-regulation model visualises how the learner can become more strategic in this process through teacher and peer assessment in which assessment knowledge and regulation strategies are shared with the learner. The connections we make here are crucial to strengthening our understanding of the influence of assessment practices on students’ learnin

Separable concatenated codes with iterative map decoding for Rician fading channels

Very efficient signalling in radio channels requires the design of very powerful codes having special structure suitable for practical decoding schemes. In this paper, powerful codes are obtained by combining comparatively simple convolutional codes to form multi-tiered 'separable' convolutional codes. The decoding of these codes, using separable symbol-by-symbol maximum a posteriori (MAP) 'filters', is described. It is known that this approach yields impressive results in non-fading additive white Gaussian noise channels. Interleaving is an inherent part of the code construction, and consequently, these codes are well suited for fading channel communications. Here, simulation results for communications over Rician fading channels are presented to support this claim

Investigative school research projects in biology: Effects on students

Science education is sometimes orientated around students learning science by doing science. Investigative research projects may be intended to reflect some aspects of science more authentically than other teaching and learning approaches, such as confirmatory practical activities and teacher demonstrations. What remains under-researched is what the effects on students are as a result of undertaking such projects. In this study we collected data from students who were participating in investigative research projects. Our research question is ‘How do secondary school students participating in a biology research project see science and themselves in relation to it?’. Twelve 12-18 year-olds who were undertaking biology research projects in England participated in 1:1 interviews in 2021. There was an association between the participants’ motivation for engaging with the investigative research project and their science identities, with many of them articulating that the project provided them with an “authentic” experience of what “real scientists” do. Participants were nearly always positive about taking part in a research project; this was particularly the case for those students who presented their findings at a conference, where presenters received feedback from peers and members of the science community. For some of the participants, engaging in an investigative research project afforded them opportunities not only to develop their scientific inquiry skills but to gain a deeper understanding of the epistemological dimensions of science and its connection with historical, cultural and social values. This greater appreciation and insight into the nature of science increased their science-related career aspirations

Cryptococcus at work: Gene expression during human infection

Meningitis is a frequent manifestation of infection due to Cryptococcus neoformans and a major cause of increased morbidity in patients with AIDS. Numerous in vitro gene expression and genetic studies of the fungus have predicted a myriad of genes, pathways, and biological processes that may be critical for pathogenesis, and many studies using animal models have supported the role of these processes during infection. However, the relevance of these hypotheses based on in vitro and animal models has often been questioned. A recent study by Chen et al. [Y. Chen, D. L. Toffaletti, J. L. Tenor, A. P. Litvintseva, C. Fang, T. G. Mitchell, T. R. McDonald, K. Nielsen, D. R. Boulware, T. Bicanic, and J. R. Perfect, mBio 5(1):e01087-13, 2014] represents an important step in understanding the cryptococcal response during human infection

Role of Cryptococcus neoformans Rho1 GTPases in the PKC1 signaling pathway in response to thermal stress

To initiate and establish infection in mammals, the opportunistic fungal pathogen Cryptococcus neoformans must survive and thrive upon subjection to host temperature. Primary maintenance of cell integrity is controlled through the protein kinase C1 (PKC1) signaling pathway, which is regulated by a Rho1 GTPase in Saccharomyces cerevisiae. We identified three C. neoformans Rho GTPases, Rho1, Rho10, and Rho11, and have begun to elucidate their role in growth and activation of the PKC1 pathway in response to thermal stress. Western blot analysis revealed that heat shock of wild-type cells resulted in phosphorylation of Mpk1 mitogen-activated protein kinase (MAPK). Constitutive activation of Rho1 caused phosphorylation of Mpk1 independent of temperature, indicating its role in pathway regulation. A strain with a deletion of RHO10 also displayed this constitutive Mpk1 phosphorylation phenotype, while one with a deletion of RHO11 yielded phosphorylation similar to that of wild type. Surprisingly, like a rho10Δ strain, a strain with a deletion of both RHO10 and RHO11 displayed temperature sensitivity but mimicked wild-type phosphorylation, which suggests that Rho10 and Rho11 have coordinately regulated functions. Heat shock-induced Mpk1 phosphorylation also required the PKC1 pathway kinases Bck1 and Mkk2. However, Pkc1, thought to be the major regulatory kinase of the cell integrity pathway, was dispensable for this response. Together, our results argue that Rho proteins likely interact via downstream components of the PKC1 pathway or by alternative pathways to activate the cell integrity pathway in C. neoformans