1,927 research outputs found

    Limits To Certainty in QoS Pricing and Bandwidth

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    Advanced services require more reliable bandwidth than currently provided by the Internet Protocol, even with the reliability enhancements provided by TCP. More reliable bandwidth will be provided through QoS (quality of service), as currently discussed widely. Yet QoS has some implications beyond providing ubiquitous access to advance Internet service, which are of interest from a policy perspective. In particular, what are the implications for price of Internet services? Further, how will these changes impact demand and universal service for the Internet. This paper explores the relationship between certainty of bandwidth and certainty of price for Internet services over a statistically shared network and finds that these are mutually exclusive goals.Comment: 29th TPRC Conference, 200

    Skeletal muscle differentiation drives a dramatic downregulation of RNA polymerase III activity and differential expression of Polr3g isoforms

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    Gene regulatory networks underpinning skeletal muscle determination and differentiation have been extensively investigated, providing molecular insights into how cell lineages are established during development. These studies have exclusively focused on the transcriptome downstream of RNA polymerase II (Pol II). RNA polymerase III (Pol III) drives the production of tRNAs and other small RNAs essential for the flow of genetic information from gene to protein and we have found that a specific isoform of a subunit unique to Pol III is expressed early in the myogenic lineage. This points to the possibility that additional regulatory networks exist to control the production of Pol III transcripts during skeletal muscle differentiation. We describe the differential expression of Polr3g and its alternate isoform Polr3gL during embryonic development and using a custom tRNA microarray, we demonstrate their distinct activity on the synthesis of tRNA isoacceptors. We show that Pol III dependent transcripts are dramatically down-regulated during the differentiation of skeletal muscle, as are mRNAs coding for Pol III associated proteins Brf1 and Brf2, while Polr3gL is up-regulated alongside contractile protein genes. Forcing Polr3g expression in this context results in a partial reversal of myogenic differentiation

    ‘Loob’ and ‘Labas’: Spatial Constructions of Safety and Risk Amid the COVID-19 Pandemic in the Philippines

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    This article argues that local constructions of risky and safe spaces, as articulated by the notions ‘loob’ (inside) and ‘labas’ (outside), informed popular and political responses to the COVID-19 pandemic in the Philippines, leading to an overemphasis on staying at home and, conversely, a general avoidance or fear of outdoor spaces that was at times reinforced by public health authorities. Practices and policies related to the pandemic response rendered this binary opposition between ‘loob’ and ‘labas’ visible, from regulations concerning the use of personal protective equipment to restrictions of access to outdoor spaces. While this emergent form of bodily proxemics was contested and negotiated over time, its tenacity throughout the pandemic underscores the importance of understanding how people spatialize risk in times of health crises

    Perancangan Dan Pembuatan Aplikasi Skeletonization

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    Perkembangan teknologi pengolahan citra sangatlah berkembang saat ini, diantaranya adalah pengenalan obyek pada citra. Algoritma untuk mendapatkan hasil yang akurat dalam pengenalan obyek terus dikembangkan. Salah satu contohnya adalah aplikasi pengenalan tulisan tangan. Aplikasi ini biasanya digunakan untuk mengarsipkan catatan atau dokumen dari bentuk fisik seperti buku catatan maupun surat kedalam bentuk file digital.Salah satu proses awal dalam pengolahan citra adalah segmentasi citra, dan salah satu metode yang digunakan adalah skeletonizatonSkeletonization ini menggunakan metode Discrete Local Symmetry. Proses dimulai dengan menetapkan active contour dari citra. Dari active contour tersebut dilakukan proses triangulation. Dan dari proses tersebut dicari titik simetri. Kemudian dilakukan proses skeletonization menggunakan titik simetri yang didapatkan.Hasil pengujian menunjukkan bahwa ukuran sebuah citra sangat mempengaruhi hasil proses skeletonization menggunakan metode Discrete Local Symmetry. Metode Discrete Local Symmetry cocok digunakan untuk benda yang berbentuk ribbon-lik

    The era of the ARG: an empiricist's guide to ancestral recombination graphs

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    In the presence of recombination, the evolutionary relationships between a set of sampled genomes cannot be described by a single genealogical tree. Instead, the genomes are related by a complex, interwoven collection of genealogies formalized in a structure called an ancestral recombination graph (ARG). An ARG extensively encodes the ancestry of the genome(s) and thus is replete with valuable information for addressing diverse questions in evolutionary biology. Despite its potential utility, technological and methodological limitations, along with a lack of approachable literature, have severely restricted awareness and application of ARGs in empirical evolution research. Excitingly, recent progress in ARG reconstruction and simulation have made ARG-based approaches feasible for many questions and systems. In this review, we provide an accessible introduction and exploration of ARGs, survey recent methodological breakthroughs, and describe the potential for ARGs to further existing goals and open avenues of inquiry that were previously inaccessible in evolutionary genomics. Through this discussion, we aim to more widely disseminate the promise of ARGs in evolutionary genomics and encourage the broader development and adoption of ARG-based inference.Comment: 34 pages, 3 figures, 3 table

    Hippocampal neuronal cells that accumulate α-synuclein fragments are more vulnerable to Aβ oligomer toxicity via mGluR5--implications for dementia with Lewy bodies.

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    BackgroundIn dementia with Lewy bodies (DLB) abnormal interactions between α-synuclein (α-syn) and beta amyloid (Aβ) result in selective degeneration of neurons in the neocortex, limbic system and striatum. However, factors rendering these neurons selectively vulnerable have not been fully investigated. The metabotropic glutamate receptor 5 (mGluR5) has been shown to be up regulated in DLB and might play a role as a mediator of the neurotoxic effects of Aβ and α-syn in vulnerable neuronal populations. In this context, the main objective of the present study was to investigate the role of mGluR5 as a mediator of the neurotoxic effects of α-syn and Aβ in the hippocampus.ResultsWe generated double transgenic mice over-expressing amyloid precursor protein (APP) and α-syn under the mThy1 cassette and investigated the relationship between α-syn cleavage, Aβ, mGluR5 and neurodegeneration in the hippocampus. We found that compared to the single tg mice, the α-syn/APP tg mice displayed greater accumulation of α-syn and mGluR5 in the CA3 region of the hippocampus compared to the CA1 and other regions. This was accompanied by loss of CA3 (but not CA1) neurons in the single and α-syn/APP tg mice and greater loss of MAP 2 and synaptophysin in the CA3 in the α-syn/APP tg. mGluR5 gene transfer using a lentiviral vector into the hippocampus CA1 region resulted in greater α-syn accumulation and neurodegeneration in the single and α-syn/APP tg mice. In contrast, silencing mGluR5 with a lenti-shRNA protected neurons in the CA3 region of tg mice. In vitro, greater toxicity was observed in primary hippocampal neuronal cultures treated with Aβ oligomers and over-expressing α-syn; this effect was attenuated by down-regulating mGluR5 with an shRNA lentiviral vector. In α-syn-expressing neuronal cells lines, Aβ oligomers promoted increased intracellular calcium levels, calpain activation and α-syn cleavage resulting in caspase-3-dependent cell death. Treatment with pharmacological mGluR5 inhibitors such as 2-Methyl-6-(phenylethynyl)pyridine (MPEP) and 3-((2-Methyl-4-thiazolyl)ethynyl)pyridine (MTEP) attenuated the toxic effects of Aβ in α-syn-expressing neuronal cells.ConclusionsTogether, these results support the possibility that vulnerability of hippocampal neurons to α-syn and Aβ might be mediated via mGluR5. Moreover, therapeutical interventions targeting mGluR5 might have a role in DLB

    Synthesis of anisotropic 3D nanomagnets for magnetic actuation and sensing in piezoelectric polyvinylidene fluoride towards magnetic nanogenerator device fabrication

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    The 3D geometry and anisotropic properties of magnetic nanostructures has been found to have a direct impact on their magnetization properties due to spatial coordinates and larger surface areas, which sheds new light on next-generation materials for advanced applications in magnetic energy harvesting. Our work presents novel pathways for the synthesis and assembly of multifunctional anisotropic 3D nanomagnets with various shapes and sizes with key attention to their anisotropic morphologies. We investigated the excellent properties of these new anisotropic 3D nanomagnets for the design of magnetic actuator systems and nanogenerators by embedding the 3D nanomagnets in a piezoelectric polyvinylidene fluoride (PVDF) polymer matrix. The 3D nanomagnets-PDVF composites were found to exhibit the highly electroactive β-phase with enhanced piezoelectric sensitivity. Further, the 3D nanomagnets-PDVF thin films have outstanding magnetic responsiveness and actuation capacity ideal for the fabrication of magnetic nanogenerators. These types of materials have a great deal of potential to generate sustainable alternative energy sources through harvesting and conversion of ubiquitous and residual low-frequency environmental magnetic noise into usable electricity

    Synthesis of anisotropic 3D nanomagnets for magnetic actuation and sensing in piezoelectric polyvinylidene fluoride towards magnetic nanogenerator device fabrication

    Get PDF
    The 3D geometry and anisotropic properties of magnetic nanostructures has been found to have a direct impact on their magnetization properties due to spatial coordinates and larger surface areas, which sheds new light on next-generation materials for advanced applications in magnetic energy harvesting. Our work presents novel pathways for the synthesis and assembly of multifunctional anisotropic 3D nanomagnets with various shapes and sizes with key attention to their anisotropic morphologies. We investigated the excellent properties of these new anisotropic 3D nanomagnets for the design of magnetic actuator systems and nanogenerators by embedding the 3D nanomagnets in a piezoelectric polyvinylidene fluoride (PVDF) polymer matrix. The 3D nanomagnets-PDVF composites were found to exhibit the highly electroactive β-phase with enhanced piezoelectric sensitivity. Further, the 3D nanomagnets-PDVF thin films have outstanding magnetic responsiveness and actuation capacity ideal for the fabrication of magnetic nanogenerators. These types of materials have a great deal of potential to generate sustainable alternative energy sources through harvesting and conversion of ubiquitous and residual low-frequency environmental magnetic noise into usable electricity
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