SIP-based proactive and adaptive mobility management framework for heterogeneous networks

Abstract In this paper, we present and evaluate the performance of a mobility management system called the Proactive and Adaptive Handover (PAHO) system. PAHO is an application-level approach that uses SIP to manage client-initiated connection handoff across heterogeneous networks based on the IEEE 802.21 framework with designated user/configuration policy. Unlike conventional systems which make sub-optimal decision when managing connection handoff due to limited awareness of the relevant context for the application/service being delivered, PAHO defines proper interface to interact with the application as to determine when and to where the handoff and/or codec switching should take place in the event of network performance degradation. The results showed that using the PAHO approach on an audio/video conferencing session helps reducing the overall handover delay from 10.766 s (on non-PAHO system) down to at least 288 ms, and slowing down the degradation of MOS value throughout the entire experiment in the event of signal degradation as well as network congestion. It is also shown that load balancing among the access points (AP) could be achieved with an improved Information Server (IS). r 2007 Elsevier Ltd. All rights reserved

Dengue Virus Activates Polyreactive, Natural IgG B Cells after Primary and Secondary Infection

BACKGROUND: Dengue virus is transmitted by mosquitoes and has four serotypes. Cross-protection to other serotypes lasting for a few months is observed following infection with one serotype. There is evidence that low-affinity T and/or B cells from primary infections contribute to the severe syndromes often associated with secondary dengue infections. such pronounced immune-mediated enhancement suggests a dengue-specific pattern of immune cell activation. This study investigates the acute and early convalescent B cell response leading to the generation of cross-reactive and neutralizing antibodies following dengue infection. METHODOLOGY/PRINCIPAL FINDINGS: We assayed blood samples taken from dengue patients with primary or secondary infection during acute disease and convalescence and compared them to samples from patients presenting with non-dengue related fever. Dengue induced massive early plasmablast formation, which correlated with the appearance of polyclonal, cross-reactive IgG for both primary and secondary infection. Surprisingly, the contribution of IgG to the neutralizing titer 4-7 days after fever onset was more than 50% even after primary infection. CONCLUSIONS/SIGNIFICANCE: Poly-reactive and virus serotype cross-reactive IgG are an important component of the innate response in humans during both primary and secondary dengue infection, and "innate specificities" seem to constitute part of the adaptive response in dengue. While of potential importance for protection during secondary infection, cross-reactive B cells will also compete with highly neutralizing B cells and possibly interfere with their development

The Early Clinical Features of Dengue in Adults: Challenges for Early Clinical Diagnosis

Dengue infection in adults has become increasingly common throughout the world. As most of the clinical features of dengue have been described in children, we undertook a prospective study to determine the early symptoms and signs of dengue in adults. We show here that, overall, dengue cases presented with high rates of symptoms listed in the WHO 1997 or 2009 classification schemes for probable dengue fever thus resulting in high sensitivities of these schemes when applied for early diagnosis. However, symptoms such as myalgia, arthralgia, retro-orbital pain and mucosal bleeding were less frequently reported in older adults. This trend resulted in reduced sensitivity of the WHO classification schemes in older adults even though they showed increased risks of hospitalization and severe dengue. Instead, we suggest that older adults who present with fever and leukopenia should be tested for dengue, even in the absence of other symptoms. This could be useful for early clinical diagnosis in older adults so that they can be monitored and treated for severe dengue, which is especially important when an antiviral drug becomes available

Genomic insights into rapid speciation within the world's largest tree genus Syzygium

The relative importance of the mechanisms underlying species radiation remains unclear. Here, the authors combine reference genome assembly and population genetics analyses to show that neutral forces have contributed to the radiation of the most species-rich tree genus Syzygium. Species radiations, despite immense phenotypic variation, can be difficult to resolve phylogenetically when genetic change poorly matches the rapidity of diversification. Genomic potential furnished by palaeopolyploidy, and relative roles for adaptation, random drift and hybridisation in the apportionment of genetic variation, remain poorly understood factors. Here, we study these aspects in a model radiation, Syzygium, the most species-rich tree genus worldwide. Genomes of 182 distinct species and 58 unidentified taxa are compared against a chromosome-level reference genome of the sea apple, Syzygium grande. We show that while Syzygium shares an ancient genome doubling event with other Myrtales, little evidence exists for recent polyploidy events. Phylogenomics confirms that Syzygium originated in Australia-New Guinea and diversified in multiple migrations, eastward to the Pacific and westward to India and Africa, in bursts of speciation visible as poorly resolved branches on phylogenies. Furthermore, some sublineages demonstrate genomic clines that recapitulate cladogenetic events, suggesting that stepwise geographic speciation, a neutral process, has been important in Syzygium diversification.Peer reviewe

Genomic insights into rapid speciation within the world's largest tree genus Syzygium

Acknowledgements Y.W.L. was supported by a postgraduate scholarship research grant from the Ministry of National Development, Singapore awarded through the National Parks Board, Singapore (NParks; NParks’ Garden City Fund). Principal research funding from NParks and the School of Biological Sciences (SBS), Nanyang Technological University (NTU), Singapore, is acknowledged. We thank Peter Preiser, Associate Vice President for Biomedical and Life Sciences, for facilitating NTU support, and Kenneth Er, CEO of NParks, for facilitating research funding through that organisation. V.A.A. and C.L. were funded by SBS, NTU for a one-year research leave. V.A.A. and C.L. also acknowledge support from the United States National Science Foundation (grants 2030871 and 1854550, respectively). S.R. was supported by a postdoctoral research fellowship under the NTU Strategic Plant Programme. S.R. and N.R.W.C. acknowledge funding from NTU start-up and the Academy of Finland (decisions 318288, 319947) grants to J.S. Fieldwork conducted by Y.W.L. was supported by an Indonesian Government RISTEK research permit (Application ID: 1517217008) and an Access License from the Sabah State government [JKM/MBS.1000-2/2JLD.7(84)]. T.N.C.V. is grateful to the Assemblée de la Province Nord and Assemblée de la Province Sud (New Caledonia) for facilitating relevant collection permits. A.N. was partly supported by the Research Project Promotion Grant (Strategic Research Grant No. 17SP01302) from the University of the Ryukyus, and partly by the Environment Research and Technology Development Fund (JPMEERF20204003) from the Environmental Restoration and Conservation Agency of Japan. Fieldwork in Fiji conducted by R.B. was hosted and facilitated by Elina Nabubuniyaka-Young (The Pacific Community’s Centre for Pacific Crops and Trees, Fiji). We thank the NTU-Smithsonian Partnership for tree data obtained for the Bukit Timah Nature Reserve (BTNR) long-term forest dynamics plots. Administrative support provided by Mui Hwang Khoo-Woon and Peter Ang at the molecular laboratory of the Singapore Botanic Gardens (SBG) is acknowledged. Rosie Woods and Imalka Kahandawala (DNA and Tissue Bank, Royal Botanic Gardens, Kew) facilitated additional DNA samples. Daniel Thomas (SBG) and Yan Yu (Sichuan University) commented on biogeographical analyses. NovogeneAIT in Singapore is acknowledged for personalised sequencing service.Peer reviewedPublisher PD

Collectively Improving Our Teaching: Attempting Biology Department–wide Professional Development in Scientific Teaching

Many efforts to improve science teaching in higher education focus on a few faculty members at an institution at a time, with limited published evidence on attempts to engage faculty across entire departments. We created a long-term, department-wide collaborative professional development program, Biology Faculty Explorations in Scientific Teaching (Biology FEST). Across 3 years of Biology FEST, 89% of the department's faculty completed a weeklong scientific teaching institute, and 83% of eligible instructors participated in additional semester-long follow-up programs. A semester after institute completion, the majority of Biology FEST alumni reported adding active learning to their courses. These instructor self-reports were corroborated by audio analysis of classroom noise and surveys of students in biology courses on the frequency of active-learning techniques used in classes taught by Biology FEST alumni and nonalumni. Three years after Biology FEST launched, faculty participants overwhelmingly reported that their teaching was positively affected. Unexpectedly, most respondents also believed that they had improved relationships with departmental colleagues and felt a greater sense of belonging to the department. Overall, our results indicate that biology department-wide collaborative efforts to develop scientific teaching skills can indeed attract large numbers of faculty, spark widespread change in teaching practices, and improve departmental relations

Sarcoma classification by DNA methylation profiling

Sarcomas are malignant soft tissue and bone tumours affecting adults, adolescents and children. They represent a morphologically heterogeneous class of tumours and some entities lack defining histopathological features. Therefore, the diagnosis of sarcomas is burdened with a high inter-observer variability and misclassification rate. Here, we demonstrate classification of soft tissue and bone tumours using a machine learning classifier algorithm based on array-generated DNA methylation data. This sarcoma classifier is trained using a dataset of 1077 methylation profiles from comprehensively pre-characterized cases comprising 62 tumour methylation classes constituting a broad range of soft tissue and bone sarcoma subtypes across the entire age spectrum. The performance is validated in a cohort of 428 sarcomatous tumours, of which 322 cases were classified by the sarcoma classifier. Our results demonstrate the potential of the DNA methylation-based sarcoma classification for research and future diagnostic applications