1,187 research outputs found

    Theory and design of a class of cosine-modulated non-uniform filter banks

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    In this paper, the theory and design of a class of PR cosine-modulated nonuniform filter bank is proposed. It is based on a structure previously proposed by Cox, where the outputs of a uniform filter bank is combined or merged by means of the synthesis section of another filter bank with smaller channel number. Simplifications are imposed on this structure so that the design procedure can be considerably simplified. Due to the use of CMFB as the original and recombination filter banks, excellent filter quality and low design and implementation complexities can be achieved. Problems with these merging techniques such as spectrum inversion, equivalent filter representations and protrusion cancellation are also addressed. As the merging is performed after the decimation, the arithmetic complexity is lower than other conventional approaches. Design examples show that PR nonuniform filter banks with high stopband attenuation and low design and implementation complexities can be obtained by the proposed method.published_or_final_versio

    A new fast sub-optimal search method for closed-loop transmit diversity system with limited number of feedback bits

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    IEEE Radio and Wireless Conference, Atlanta, Georgia, USA, 19-22 September 2004In this paper, we present a fast sub-optimal searching algorithm for the closed-loop transmit diversity scheme used in wireless system. Under the low mobility condition and with perfect channel knowledge at the receiving end, our proposed searching algorithm can use a limited number of feedback bits to provide a sub-optimal solution that can achieve the SNR values close to the optimal solution with a greatly reduced complexity and outperform other sub-optimal schemes. The scheme also works well under the presence of feedback errors. © 2004 IEEE.published_or_final_versio

    Novel search algorithm for closed-loop transmit diversity system with limited number of feedback bits

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    We propose two simple closed-loop transmit diversity schemes with a fixed number of feedback bits being allocated for each transmit antenna. Under a low mobility condition and with perfect channel knowledge at the receiver, we show that our proposed schemes can achieve signal-to-noise ratio (SNR) values close to the optimal solution but with greatly reduced complexity. We also show that our methods outperform other suboptimal schemes such as the co-phasing method. © 2004 IEEE.published_or_final_versionIEEE 60th Vehicular Technology Conference 2004-Fall (VTC2004-Fall), "Wireless Technologies for Global Security", Los Angeles, CA, USA, 26-29 September 2004. In IEEE - VTS Vehicular Technology Conference Proceedings, 2004, v. 60 n. 3, p. 1849-185

    A Discrete Event Simulation model to evaluate the treatment pathways of patients with Cataract in the United Kingdom

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    Background The number of people affected by cataract in the United Kingdom (UK) is growing rapidly due to ageing population. As the only way to treat cataract is through surgery, there is a high demand for this type of surgery and figures indicate that it is the most performed type of surgery in the UK. The National Health Service (NHS), which provides free of charge care in the UK, is under huge financial pressure due to budget austerity in the last decade. As the number of people affected by the disease is expected to grow significantly in coming years, the aim of this study is to evaluate whether the introduction of new processes and medical technologies will enable cataract services to cope with the demand within the NHS funding constraints. Methods We developed a Discrete Event Simulation model representing the cataract services pathways at Leicester Royal Infirmary Hospital. The model was inputted with data from national and local sources as well as from a surgery demand forecasting model developed in the study. The model was verified and validated with the participation of the cataract services clinical and management teams. Results Four scenarios involving increased number of surgeries per half-day surgery theatre slot were simulated. Results indicate that the total number of surgeries per year could be increased by 40% at no extra cost. However, the rate of improvement decreases for increased number of surgeries per half-day surgery theatre slot due to a higher number of cancelled surgeries. Productivity is expected to improve as the total number of doctors and nurses hours will increase by 5 and 12% respectively. However, non-human resources such as pre-surgery rooms and post-surgery recovery chairs are under-utilized across all scenarios. Conclusions Using new processes and medical technologies for cataract surgery is a promising way to deal with the expected higher demand especially as this could be achieved with limited impact on costs. Non-human resources capacity need to be evenly levelled across the surgery pathway to improve their utilisation. The performance of cataract services could be improved by better communication with and proactive management of patients.Peer reviewedFinal Published versio

    Star forming dwarf galaxies

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    Star forming dwarf galaxies (SFDGs) have a high gas content and low metallicities, reminiscent of the basic entities in hierarchical galaxy formation scenarios. In the young universe they probably also played a major role in the cosmic reionization. Their abundant presence in the local volume and their youthful character make them ideal objects for detailed studies of the initial stellar mass function (IMF), fundamental star formation processes and its feedback to the interstellar medium. Occasionally we witness SFDGs involved in extreme starbursts, giving rise to strongly elevated production of super star clusters and global superwinds, mechanisms yet to be explored in more detail. SFDGs is the initial state of all dwarf galaxies and the relation to the environment provides us with a key to how different types of dwarf galaxies are emerging. In this review we will put the emphasis on the exotic starburst phase, as it seems less important for present day galaxy evolution but perhaps fundamental in the initial phase of galaxy formation.Comment: To appear in JENAM Symposium "Dwarf Galaxies: Keys to Galaxy Formation and Evolution", P. Papaderos, G. Hensler, S. Recchi (eds.). Lisbon, September 2010, Springer Verlag, in pres

    Estimating Costs Associated with Adverse Events in Patients with Advanced Lung Cancer

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    Chien-Yu Lin,1 Tzu-I Wu,1,2 Szu-Chun Yang1 1Division of Thoracic Medicine, Department of Internal Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan; 2Department of Public Health, College of Medicine, National Cheng Kung University, Tainan, TaiwanCorrespondence: Szu-Chun Yang, Email [email protected]: This study aimed to estimate the costs associated with adverse events (AEs) in advanced lung cancer patients treated with first-line therapies.Subjects and Methods: All patients with advanced lung cancer diagnosed between 2011 and 2019 were identified from the Taiwan National Cancer Registry. First-line treatment was defined as a therapy that began within 30 days before and 90 days after the diagnosis. We defined a newly-developed AE as one established after first-line treatment had commenced, with the contingency that the patient had not been diagnosed with the AE within one year prior to the outset of therapy. One patient with a specific AE was matched on age, sex, and regimens with four patients without the AE. Payments incurred over the same period of time in the two groups were compared to estimate the AE-related costs.Results: A total of 27,376 patients receiving first-line targeted therapy, immunotherapy, or chemotherapy were identified. Clinical characteristics of 15,454 treatment episodes with a specific AE and 61,816 treatment episodes without the AE were well balanced. The costliest AEs of any severity were sepsis/septicemia, neuropathy, and acute kidney injury, with the respective average incremental costs of 10101, 9982, and 7839 USD. The costliest severe AEs requiring hospitalization were sepsis/septicemia, interstitial lung disease/pneumonitis, and neuropathy, with mean incremental costs of 22483, 10645, and 10120 USD, respectively.Conclusion: Costs associated with AEs in advanced lung cancer patients treated with first-line therapies were substantial. These estimates could be adopted for future cost-effectiveness analyses of new lung cancer treatments.Keywords: adverse event, side effect, cost, lung cancer, utilizatio

    The developmental regulator Pax6 is essential for maintenance of islet cell function in the adult mouse pancreas

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    The transcription factor Pax6 is a developmental regulator with a crucial role in development of the eye, brain, and olfactory system. Pax6 is also required for correct development of the endocrine pancreas and specification of hormone producing endocrine cell types. Glucagon-producing cells are almost completely lost in Pax6-null embryos, and insulin-expressing beta and somatostatin-expressing delta cells are reduced. While the developmental role of Pax6 is well-established, investigation of a further role for Pax6 in the maintenance of adult pancreatic function is normally precluded due to neonatal lethality of Pax6-null mice. Here a tamoxifen-inducible ubiquitous Cre transgene was used to inactivate Pax6 at 6 months of age in a conditional mouse model to assess the effect of losing Pax6 function in adulthood. The effect on glucose homeostasis and the expression of key islet cell markers was measured. Homozygous Pax6 deletion mice, but not controls, presented with all the symptoms of classical diabetes leading to severe weight loss requiring termination of the experiment five weeks after first tamoxifen administration. Immunohistochemical analysis of the pancreata revealed almost complete loss of Pax6 and much reduced expression of insulin, glucagon, and somatostatin. Several other markers of islet cell function were also affected. Notably, strong upregulation in the number of ghrelin-expressing endocrine cells was observed. These findings demonstrate that Pax6 is essential for adult maintenance of glucose homeostasis and function of the endocrine pancreas

    The genomic evolution of human prostate cancer.

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    Prostate cancers are highly prevalent in the developed world, with inheritable risk contributing appreciably to tumour development. Genomic heterogeneity within individual prostate glands and between patients derives predominantly from structural variants and copy-number aberrations. Subtypes of prostate cancers are being delineated through the increasing use of next-generation sequencing, but these subtypes are yet to be used to guide the prognosis or therapeutic strategy. Herein, we review our current knowledge of the mutational landscape of human prostate cancer, describing what is known of the common mutations underpinning its development. We evaluate recurrent prostate-specific mutations prior to discussing the mutational events that are shared both in prostate cancer and across multiple cancer types. From these data, we construct a putative overview of the genomic evolution of human prostate cancer
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