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| 2. |
- A Atlasov, Kirill, et al.
(författare)
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1D photonic band formation and photon localization in finite-size photonic-crystal waveguides
- 2010
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Ingår i: OPTICS EXPRESS. - 1094-4087. ; 18:1, s. 117-122
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Tidskriftsartikel (refereegranskat)abstract
- A transition from discrete optical modes to 1D photonic bands is experimentally observed and numerically studied in planar photonic-crystal (PhC) L-N microcavities of length N. For increasing N the confined modes progressively acquire a well-defined momentum, eventually reconstructing the band dispersion of the corresponding waveguide. Furthermore, photon localization due to disorder is observed experimentally in the membrane PhCs using spatially resolved photoluminescence spectroscopy. Implications on single-photon sources and transfer lines based on quasi-1D PhC structures are discussed.
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| 3. |
- A Herrera, I, et al.
(författare)
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Comparing a multi-linear (STEP) and systemic (FRAM) method for accident analysis
- 2010
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Ingår i: RELIABILITY ENGINEERING and SYSTEM SAFETY. - London, UK : Elsevier Science B.V., Amsterdam.. - 0951-8320. ; 95:12, s. 1269-1275, s. 19-26
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Tidskriftsartikel (refereegranskat)abstract
- Accident models and analysis methods affect what accident investigators look for, which contributory factors are found, and which recommendations are issued. This paper contrasts the Sequentially Timed Events Plotting (STEP) method and the Functional Resonance Analysis Method (FRAM) for accident analysis and modelling. The main issue addressed in this paper is the comparison of the established multi-linear method STEP with the new systemic method FRAM and which new insights the latter provides for accident analysis in comparison to the former established multi-linear method. Since STEP and FRAM are based on a different understandings of the nature of accidents, the comparison of the methods focuses on what we can learn from both methods, how, when, and why to apply them. The main finding is that STEP helps to illustrate what happened, involving which actors at what time, whereas FRAM illustrates the dynamic interactions within socio-technical systems and lets the analyst understand the how and why by describing non-linear dependencies, performance conditions, variability, and their resonance across functions.
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| 4. |
- A Hulten, Maj, et al.
(författare)
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On the origin of the maternal age effect in trisomy 21 Down syndrome: the Oocyte Mosaicism Selection model
- 2010
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Ingår i: Reproduction. - 1470-1626 .- 1476-3990. ; 139:1, s. 1-9
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Forskningsöversikt (refereegranskat)abstract
- We have recently documented that trisomy 21 mosaicism is common in human foetal ovaries. On the basis of this observation we propose that the maternal age effect in Down syndrome (DS) is caused by the differential behaviour of trisomy 21 in relation to disomy 21 oocytes during development from foetal life until ovulation in adulthood. in particular, we suggest that trisomy 21 oocytes, lagging behind those that are disomic, may escape the timed pruning of the seven million in foetal life to the 300-400 finally selected for ovulation. The net effect of this preferential elimination will be an accumulation of trisomy 21 oocytes in the ovarian reserve of older women. We here highlight the implications of this Oocyte Mosaicism Selection (OMS) model with respect to the prevalent view that the maternal age effect is complex, dependent on many different biological and environmental factors. We examine conclusions drawn from recent large-scale studies in families, tracing DNA markers along the length of chromosome 21q between parents and DS children, in comparison to the OMS model. We conclude that these family linkage data are equally compatible with the maternal age effect originating from the accumulation of trisomy 21 oocytes with advancing maternal age. One relatively straightforward way to get to grips with what is actually going on in this regard would be to compare incidence of trisomy 21 oocytes (and their pairing configurations) in foetal ovaries with that in oocytes at the meiosis I stage from adult women.
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| 5. |
- Aamir, Syed Ahmed, 1980-, et al.
(författare)
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A 1.2-V pseudo-differential OTA with common-mode feedforward in 65-nm CMOS
- 2010
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Ingår i: Proceedings of the 17th IEEE International Conference on Electronics, Circuits, and Systems. - : Institute of Electrical and Electronics Engineers (IEEE). ; , s. 29-32
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Konferensbidrag (refereegranskat)abstract
- In this work, we describe the implementation of a 1. 2-V pseudo-differential operational transconductance amplifier (OTA) with common-mode feedforward (CMFF) and inherent common-mode feedback (CMFB) in a 65-nm, digital CMOS process. The OTA architecture provides an inherent CMFB when cascaded OTA structures are utilized andthis work has studied a cascaded amplifier consisting of fourstages. Due to the low-gain using core 65-nm circuit devices, the overall gain must be distributed on all four stages to acquire a gain of more than 60 dB, while maintaining a-3-dB bandwidth of 200 MHz. To achieve high gain, we propose using a modified, positive-feedback, cross-coupled input differential stage. The modified OTA achieves a high output swing of ± 0.85 V due to only two stacked transistors, 88 dB DC gain and a third-order harmonic of -60 dB for 800 mVpp at 30 MHz. Further on, in a capacitive buffer configuration, we achieve a high slew rate of 1240 V/µS, -3-dB bandwidth of 509 MHz, signal-to-noise ratio of 63 dB while consuming 10.4 mW power.
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| 6. |
- Aamir, Syed Ahmed, 1980-, et al.
(författare)
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A 500-MHz low-voltage programmable gain amplifier for HD video in 65-nm CMOS
- 2010
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Ingår i: Proceedings of 28th IEEE Norchip Conference., NORCHIP'10. - Tampere : www.ieee.org. - 9781424489718 - 9781424489725 ; , s. 1-4
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Konferensbidrag (refereegranskat)abstract
- This work describes the implementation of a 1.2-V programmable gain amplifier (PGA) for high-definition (HD) video digitizers in a 65-nm digital CMOS process. The “pseudo” switched-capacitor (SC) PGA architecture buffers the video signal, without switching, during the active video. The SC circuitry is used for setup of DC operating point during horizontal and vertical blanking periods. Additionally, it compensates for the `sync-tip' of analog video signals to an equal blanking level for increased dynamic range to the digitizer following the PGA. The operational transconductance amplifier (OTA) employed as main amplifier in the PGA is a pseudo-differential, positive-feedback input stage architecture with a common-mode feedforward (CMFF) technique. The common-mode feedback (CMFB) is provided once two OTAs are cascaded. Schematic-level simulation results show that the OTA maintains a -3-dB bandwidth of 550 MHz, while keeping the distortion HD3 at -60 dB for a 30-MHz, 850 mVpp high definition video signal. The 88 dB DC gain is distributed among four OTA stages and the overall, combined PGA achieves a signal-to-noise ratio of 63 dB. Due to only two stacked transistors, it achieves high output swing of ±0.85 V, 1240 V/μs slew rate while consuming 10.4 mW power.
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| 7. |
- Aarao, J, et al.
(författare)
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The extended-domain-eigenfunction method for solving elliptic boundary value problems with annular domains
- 2010
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Ingår i: JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL. - : Iop. - 1751-8113 .- 1751-8121. ; 43:18, s. 185202-
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Tidskriftsartikel (refereegranskat)abstract
- Standard analytical solutions to elliptic boundary value problems on asymmetric domains are rarely, if ever, obtainable. In this paper, we propose a solution technique wherein we embed the original domain into one with simple boundaries where the classical eigenfunction solution approach can be used. The solution in the larger domain, when restricted to the original domain, is then the solution of the original boundary value problem. We call this the extended-domain-eigenfunction method. To illustrate the methods strength and scope, we apply it to Laplaces equation on an annular-like domain.
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| 8. |
- Aasa, Mikael, et al.
(författare)
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Cost and health outcome of primary percutaneous coronary intervention versus thrombolysis in acute ST-segment elevation myocardial infarction-Results of the Swedish Early Decision reperfusion Study (SWEDES) trial.
- 2010
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Ingår i: American heart journal. - : Elsevier BV. - 1097-6744 .- 0002-8703. ; 160:2, s. 322-8
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: In ST-elevation myocardial infarction, primary percutaneous coronary intervention (PCI) has a superior clinical outcome, but it may increase costs in comparison to thrombolysis. The aim of the study was to compare costs, clinical outcome, and quality-adjusted survival between primary PCI and thrombolysis. METHODS: Patients with ST-elevation myocardial infarction were randomized to primary PCI with adjunctive enoxaparin and abciximab (n = 101), or to enoxaparin followed by reteplase (n = 104). Data on the use of health care resources, work loss, and health-related quality of life were collected during a 1-year period. Cost-effectiveness was determined by comparing costs and quality-adjusted survival. The joint distribution of incremental costs and quality-adjusted survival was analyzed using a nonparametric bootstrap approach. RESULTS: Clinical outcome did not differ significantly between the groups. Compared with the group treated with thrombolysis, the cost of interventions was higher in the PCI-treated group ($4,602 vs $3,807; P = .047), as well as the cost of drugs ($1,309 vs $1,202; P = .001), whereas the cost of hospitalization was lower ($7,344 vs $9,278; P = .025). The cost of investigations, outpatient care, and loss of production did not differ significantly between the 2 treatment arms. Total cost and quality-adjusted survival were $25,315 and 0.759 vs $27,819 and 0.728 (both not significant) for the primary PCI and thrombolysis groups, respectively. Based on the 1-year follow-up, bootstrap analysis revealed that in 80%, 88%, and 89% of the replications, the cost per health outcome gained for PCI will be <$0, $50,000, and $100,000 respectively. CONCLUSION: In a 1-year perspective, there was a tendency toward lower costs and better health outcome after primary PCI, resulting in costs for PCI in comparison to thrombolysis that will be below the conventional threshold for cost-effectiveness in 88% of bootstrap replications.
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| 9. |
- Abbas, Muhammad, et al.
(författare)
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Low-Complexity Parallel Evaluation of Powers Exploiting Bit-Level Redundancy
- 2010
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Ingår i: Conference Record of the Forty Fourth Asilomar Conference on Signals, Systems and Computers (ASILOMAR), 2010, 7-10 Nov. 2010. - Washington, DC, USA : IEEE Computer Society. - 9781424497225 ; , s. 1168-1172
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Konferensbidrag (refereegranskat)abstract
- In this work, we investigate the problem of computing any requested set of power terms in parallel using summations trees. This problem occurs in applications like polynomial approximation, Farrow filters (polynomial evaluation part) etc. In the proposed technique, the partial product of each power term is initially computed independently. A redundancy check is then made in each and among all partial products matrices at bit level. The redundancy here relates to the fact that same three partial products may be present in more than one columns, and, hence, can be mapped to the same full adder. The proposed algorithm is tested for different sets of powers and wordlengths to exploit the sharing potential.
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| 10. |
- Abbas, Muhammad, et al.
(författare)
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Power Estimation of Recursive and Non-Recursive CIC Filters Implemented in Deep-Submicron Technology
- 2010
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Ingår i: Proceedings of International Conference on Green Circuits and Systems (ICGCS), 2010, Date: 21-23 June, 2010. - : IEEE. - 9781424468775 - 9781424468768 ; , s. 221-225
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Konferensbidrag (refereegranskat)abstract
- The power modeling of different realizations of cascaded integrator-comb (CIC) decimation filters has been a subject of several recent works. In this work we have extended these with modeling of leakage power, which is an important factor since the input sample rate may differ several orders of magnitude. Furthermore, we have pointed out the importance of the input wordlength on the comparison of recursive and nonrecursive implementations.
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