| 1. |
- Duong, Quang Trung, et al.
(författare)
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Pairwise Error Probability of Distributed Space--Time Coding Employing Alamouti Scheme in Wireless Relays Networks
- 2009
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Ingår i: Wireless personal communications. - : Springer. - 0929-6212 .- 1572-834X. ; 51:2, s. 231-244
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we analyze the pairwise error probability (PEP) of distributed space-time codes, in which the source and the relay generate Alamouti space--time code in a distributed fashion. We restrict our attention to the space-time code construction for Protocol III in [1]. In particular, we derive two closed-form approximations for PEP when the relay is either close to the destination or source and an upper bound for any position of the relay. Using the alternative definition of $Q$-function, we can express these PEPs in terms of finite integral whose integrand is composed of trigonometric functions. We further show that with only one relay assisted source-destination link, system still achieves diversity order of two, assuming single-antenna terminals. We also perform Monte-Carlo simulations to verify the analysis.
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| 2. |
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| 3. |
- Brenninkmeijer, C. A. M., et al.
(författare)
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Civil Aircraft for the regular investigation of the atmosphere based on an instrumented container: The new CARIBIC system
- 2007
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Ingår i: Atmospheric Chemistry and Physics. - 1680-7324. ; 7:18, s. 4953-4976
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Tidskriftsartikel (refereegranskat)abstract
- An airfreight container with automated instruments for measurement of atmospheric gases and trace compounds was operated on a monthly basis onboard a Boeing 767-300 ER of LTU International Airways during long-distance flights from 1997 to 2002 (CARIBIC, Civil Aircraft for Regular Investigation of the Atmosphere Based on an Instrument Container, http://www.caribic-atmospheric.com). Subsequently a more advanced system has been developed, using a larger capacity container with additional equipment and an improved inlet system. CARIBIC phase #2 was implemented on a new long-range aircraft type Airbus A340-600 of the Lufthansa German Airlines (Star Alliance) in December 2004, creating a powerful flying observatory. The instrument package comprises detectors for the measurement of O-3, total and gaseous H2O, NO and NOy, CO, CO2, O-2, Hg, and number concentrations of sub-micrometer particles (>4 nm, >12 nm, and >18 nm diameter). Furthermore, an optical particle counter (OPC) and a proton transfer mass spectrometer (PTR-MS) are incorporated. Aerosol samples are collected for analysis of elemental composition and particle morphology after flight. Air samples are taken in glass containers for laboratory analyses of hydrocarbons, halocarbons and greenhouse gases (including isotopic composition of CO2) in several laboratories. Absorption tubes collect oxygenated volatile organic compounds. Three differential optical absorption spectrometers (DOAS) with their telescopes mounted in the inlet system measure atmospheric trace gases such as BrO, HONO, and NO2. A video camera mounted in the inlet provides information about clouds along the flight track. The flying observatory, its equipment and examples of measurement results are reported.
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| 4. |
- Dinh, Ngoc Phuoc, et al.
(författare)
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Functionalization of epoxy-based monoliths for ion exchange chromatography of proteins
- 2009
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Ingår i: Journal of Separation Science. - : Wiley InterScience. - 1615-9306. ; 32:15-16, s. 2556-2564
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Tidskriftsartikel (refereegranskat)abstract
- Macroporous epoxy-based monoliths prepared by emulsion polymerization have been modified for use in ion exchange chromatography (IEC) of proteins. Strong anion exchange functionality was established by iodomethane quaternization of tertiary amine present on the monolith surface as a part of the polymer backbone. The modification pathway to cation exchange materials was via incorporation of glycidyl methacrylate (GMA) brushes which were coated using atom transfer radical polymerization (ATRP). Strong (SO3-) and weak (COO-) cation exchange groups were thereafter introduced onto the GMA-grafted monoliths by reactions with sodium hydrogen sulfite and iminodiacetic acid, respectively. Grafting was confirmed by XPS, gravimetric measurement, and chromatographic behavior of the modified materials toward model proteins. In incubation experiments the proteins were recovered quantitatively with no obvious signs of unfolding after contact with the stationary phase for >2 h. Chromatographic assessments on the functionalized columns as well as problems associated with flow-through modification by ATRP are discussed.
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| 5. |
- Elsik, Christine G., et al.
(författare)
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The Genome Sequence of Taurine Cattle : A Window to Ruminant Biology and Evolution
- 2009
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 324:5926, s. 522-528
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Tidskriftsartikel (refereegranskat)abstract
- To understand the biology and evolution of ruminants, the cattle genome was sequenced to about sevenfold coverage. The cattle genome contains a minimum of 22,000 genes, with a core set of 14,345 orthologs shared among seven mammalian species of which 1217 are absent or undetected in noneutherian (marsupial or monotreme) genomes. Cattle-specific evolutionary breakpoint regions in chromosomes have a higher density of segmental duplications, enrichment of repetitive elements, and species-specific variations in genes associated with lactation and immune responsiveness. Genes involved in metabolism are generally highly conserved, although five metabolic genes are deleted or extensively diverged from their human orthologs. The cattle genome sequence thus provides a resource for understanding mammalian evolution and accelerating livestock genetic improvement for milk and meat production.
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| 6. |
- Hai, Trinh Ngoc, et al.
(författare)
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The influence of food on the pharmacokinetics of piperaquine in healthy Vietnamese volunteers.
- 2008
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Ingår i: Acta tropica. - : Elsevier BV. - 0001-706X. ; 107:2, s. 145-9
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Tidskriftsartikel (refereegranskat)abstract
- The combination piperaquine and dihydroartemisinin is emerging as first line treatment of uncomplicated falciparum malaria in Southeast Asia. The aim of this study was to determine the influence of a standard Vietnamese meal on the single-dose pharmacokinetics of piperaquine when administered in combination with dihydroartemisinin, and to gain extended data on the terminal half-life of piperaquine in healthy Vietnamese volunteers. Subjects were randomly assigned to take a single oral dose of piperaquine phosphate (640 mg)+dihydroartemisinin (80 mg) together with a standardized Vietnamese meal (n=16) or to remain fasting for 4h following drug intake (n=16). Frequent blood sampling was conducted during 36 h, followed by weekly samples for 7 weeks. The pharmacokinetic parameters of piperaquine were determined by noncompartmental analysis. The median (80% central range) AUC(0-last) was 11.5 (6.9-17.3)h mg/L in fed and 13.9 (2.8-19.3)h mg/L in fasting subjects, indicating a considerable variability in exposure in both groups. The estimated overall oral clearance was 0.27 (0.12-1.49)L/(h kg), the volume of distribution during the terminal elimination phase was 230 (102-419)L/kg and estimated terminal half-life was 18 (5-93) days. This study did not demonstrate a significant impact of a standardized Vietnamese meal on the oral absorption of piperaquine.
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| 7. |
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| 8. |
- Martinsson, Bengt, et al.
(författare)
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Characteristics and origin of lowermost stratospheric aerosol at northern midlatitudes under volcanically quiescent conditions based on CARIBIC observations
- 2005
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Ingår i: Journal of Geophysical Research. - 2156-2202. ; 110
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Tidskriftsartikel (refereegranskat)abstract
- Characteristics and origin of the aerosol in the lowermost stratosphere at northern midlatitudes were studied using measurements from a passenger aircraft ( Civil Aircraft for Regular Investigation of the Atmosphere Based on an Instrument Container, or CARIBIC). Aerosol samples were collected during 60 intercontinental flights during 1999 - 2002 and analyzed for elemental composition with particle-induced X-ray emission ( PIXE). Concurrent measurements of trace gases were used to interpret the aerosol measurements. It was found that particulate sulfur concentration increased steadily in the potential vorticity ( PV) region of 2 - 7 PVU, whereas particulate potassium and iron showed no such dependence. The variability in concentration of the latter two elements was mainly connected with season, similar to their variation in the upper troposphere, whereas PV dominated the particulate sulfur variability. An ozone-based model was developed to quantitatively determine the mixing of stratospheric and tropospheric air masses. A significant dependence on PV was found, and the stratospheric fraction of the air peaked during spring. It was found that the particulate sulfur concentration was strongly dependent on the origin of the air masses. The concentration increased by a factor of 3 over the lowermost stratosphere. A discontinuity in the concentration over the tropopause indicated particle formation from sulfur dioxide transported across the tropopause. The concentration at the top of the lowermost stratosphere was used to estimate that the particulate sulfur production in the stratosphere is 0.066 Tg S/yr with approximately half of the amount transported across the top of the lowermost stratosphere originating in carbonyl sulfide.
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| 9. |
- Nguyen, Anh Mai, et al.
(författare)
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Preparation and characterization of sizable macroporous epoxy resin-based monolithic supports for flow-through systems
- 2009
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Ingår i: Journal of Separation Science. - : Wiley InterScience. - 1615-9306 .- 1615-9314. ; 32:15-16, s. 2608-2618
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents further results from our efforts to prepare sizable macroporous monolithic materials from epoxy resins and polyamines by emulsion polymerization. For their uses as supports in flow systems, the study aimed at developing materials possessing maximum fluid permeability, high mechanical stability, and a controlled porosity and surface area. Characterization of the materials has been carried out using different techniques, focusing on morphological and mechanical features, and on the surface chemistry. Morphology and porosity were studied with SEM, nitrogen adsorption/desorption, mercury intrusion porosimetry (MIP), and (2)H NMR cryoporosimetry. The chemical composition of the bulk structures and their surfaces was studied by means of bulk elemental analysis and X-ray photoelectron spectroscopy, and potentiometric titration was used to assess the relative amounts of amines and epoxy groups. Essentially, the morphological features were a high fluid permeability, but rather low specific surface area. Convective flow was facilitated by large, interconnected, and evenly spaced macropores which were formed by nonporous skeletons of the connected-rod type. Despite the interfacial nature of the polymerization, the bulk and the surface of the fully cured materials showed similar elemental compositions. All materials were found to have a high surface density of hydroxyl groups, which facilitates functionalization reactions.
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| 10. |
- Nguyen Ngoc, Hung, et al.
(författare)
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Analysis of C, N and O in aerosol collected on an organic backing using internal blank measurements and variable beam size
- 2007
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section B: Beam Interactions with Materials and Atoms. - : Elsevier BV. - 0168-583X. ; 264:1, s. 96-102
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Tidskriftsartikel (refereegranskat)abstract
- A method with low MDL (minimum detection limit) was developed for analysis of carbon (C), nitrogen (N) and oxygen (O) in aerosol samples collected on an organic backing. An accelerator-produced beam of protons interacting with the sample and the detection of elastically scattered protons (PESA; particle elastic scattering analysis) and emitted X-rays (PIXE; particle-induced X-ray emission) were the basic components of the setup. The method is based on measurement of internal blank concentrations, i.e. measurement of the blank concentration outside the aerosol deposit in each sample, and the use of two sizes of the beam in order to improve the MDL of the analysis. Large beam size covering the entire aerosol deposit was used to obtain quantitative analysis with PIXE. Small beam was used to obtain relative elemental concentrations with PESA and PIXE, which were transformed to absolute values by the aid of large-beam analysis. The small-size-beam served two purposes: to make internal blank measurements feasible and to improve the signal ratio of aerosol-deposit to backing. Compared with the traditional way of analysis, using a beam that is larger than the deposit and specially prepared blank samples, the new method reduced the MDL of C, N and O by a factor of 130, 70 and 90, respectively. The new method was applied to aerosol samples collected in the upper troposphere and the lowermost stratosphere from the CARIBIC platform. As far as the authors know, these measurements are the first quantitative determinations of C, N and O in the aerosol of this part of the atmosphere. The results show that these elements together with sulfur are major components of the aerosol. (C) 2007 Elsevier B.V. All rights reserved.
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