| 1. |
- Schael, S, et al.
(författare)
-
Precision electroweak measurements on the Z resonance
- 2006
-
Ingår i: Physics Reports. - : Elsevier BV. - 0370-1573 .- 1873-6270. ; 427:5-6, s. 257-454
-
Forskningsöversikt (refereegranskat)abstract
- We report on the final electroweak measurements performed with data taken at the Z resonance by the experiments operating at the electron-positron colliders SLC and LEP. The data consist of 17 million Z decays accumulated by the ALEPH, DELPHI, L3 and OPAL experiments at LEP, and 600 thousand Z decays by the SLID experiment using a polarised beam at SLC. The measurements include cross-sections, forward-backward asymmetries and polarised asymmetries. The mass and width of the Z boson, m(Z) and Gamma(Z), and its couplings to fermions, for example the p parameter and the effective electroweak mixing angle for leptons, are precisely measured: m(Z) = 91.1875 +/- 0.0021 GeV, Gamma(Z) = 2.4952 +/- 0.0023 GeV, rho(l) = 1.0050 +/- 0.0010, sin(2)theta(eff)(lept) = 0.23153 +/- 0.00016. The number of light neutrino species is determined to be 2.9840 +/- 0.0082, in agreement with the three observed generations of fundamental fermions. The results are compared to the predictions of the Standard Model (SM). At the Z-pole, electroweak radiative corrections beyond the running of the QED and QCD coupling constants are observed with a significance of five standard deviations, and in agreement with the Standard Model. Of the many Z-pole measurements, the forward-backward asymmetry in b-quark production shows the largest difference with respect to its SM expectation, at the level of 2.8 standard deviations. Through radiative corrections evaluated in the framework of the Standard Model, the Z-pole data are also used to predict the mass of the top quark, m(t) = 173(+10)(+13) GeV, and the mass of the W boson, m(W) = 80.363 +/- 0.032 GeV. These indirect constraints are compared to the direct measurements, providing a stringent test of the SM. Using in addition the direct measurements of m(t) and m(W), the mass of the as yet unobserved SM Higgs boson is predicted with a relative uncertainty of about 50% and found to be less than 285 GeV at 95% confidence level. (c) 2006 Elsevier B.V. All rights reserved.
|
|
| 2. |
- Ablikim, M., et al.
(författare)
-
Measurements of (XcJ)-> K+K-K+K- decays
- 2006
-
Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 642:3, s. 197-202
-
Tidskriftsartikel (refereegranskat)abstract
- Using 14M psi(2S) events taken with the BESII detector, chi(cJ) -> 2(K+K-) decays are studied. For the four-kaon final state, the branching fractions are B(chi(c0,1,2) ->.2(K+K-)) = (3.48 +/- 0.23 +/- 0.47) x 10(-3), (0.70 +/- 0.13 +/- 0.10) x 10(-3), and (2.17 +/- 0.20 +/- 0.31) x 10(-3). For the phi K+K- final state, the branching fractions, which are measured for the first time, are B(chi(c0,1,2) -> phi K+K-) = (1.03 +/- 0.22 +/- 0.15) x 10(-3), (0.46 +/- 0.16 +/- 0.06) x 10(-3), and (1.67 +/- 0.26 +/- 0.24) x 10(-4). For the phi phi final state, B(chi(c0,2) -> phi phi) = (0.94 +/- 0.21 +/- 0.13) x 10(-3) and (1.70 +/- 0.30 +/- 0.25) x 10(-3).
|
|
| 3. |
- Rabouille, C., et al.
(författare)
-
Comparison of hypoxia among four river-dominated ocean margins: The Changjiang (Yangtze), Mississippi, Pearl, and Rhone rivers
- 2008
-
Ingår i: Continental Shelf Research. - : Elsevier BV. - 0278-4343. ; 28:12, s. 1527-1537
-
Tidskriftsartikel (refereegranskat)abstract
- We examined the occurrence of seasonal hypoxia (O-2 < 2 mg l(-1)) in the bottom waters of four river-dominated ocean margins (off the Changjiang, Mississippi, Pearl and Rhone Rivers) and compared the processes leading to the depletion of oxygen. Consumption of oxygen in bottom waters is linked to biological oxygen demand fueled by organic matter from primary production in the nutrient-rich river plume and perhaps terrigenous inputs. Hypoxia occurs when this consumption exceeds replenishment by diffusion, turbulent mixing or lateral advection of oxygenated water. The margins off the Mississippi and Changjiang are affected the most by summer hypoxia, while the margins off the Rhone and the Pearl rivers systems are less affected, although nutrient concentrations in the river water are very similar in the four systems. Spring and summer primary production is high overall for the shelves adjacent to the Mississippi, Changjiang and Pearl (1-10g C m(-2) d(-1)), and lower off the Rhone River (< 1 g C m(-2) d(-1)), which could be one of the reasons of the absence of hypoxia on the Rhone shelf The residence time of the bottom water is also related to the occurrence of hypoxia, with the Mississippi margin showing a long residence time and frequent occurrences of hypoxia during summer over very large spatial scales, whereas the East China Sea (ECS)/Changjiang displays hypoxia less regularly due to a shorter residence time of the bottom water. Physical stratification plays an important role with both the Changjiang and Mississippi shelf showing strong thermohaline stratification during summer over extended periods of time, whereas summer stratification is less prominent for the Pearl and Rhone partly due to the wind effect on mixing. The shape of the shelf is the last important factor since hypoxia occurs at intermediate depths (between 5 and 50 m) on broad shelves (Gulf of Mexico and ECS). Shallow estuaries with low residence time such as the Pearl River estuary during the summer wet season when mixing and flushing are dominant features, or deeper shelves, such as the Gulf of Lion off the Rhone show little or no hypoxia. (c) 2008 Elsevier Ltd. All rights reserved.
|
|
| 4. |
- Hibbett, D. S., et al.
(författare)
-
A higher-level phylogenetic classification of the Fungi
- 2007
-
Ingår i: Mycological Research. - : Elsevier BV. - 0953-7562 .- 1469-8102. ; 111, s. 509-547
-
Tidskriftsartikel (refereegranskat)abstract
- A comprehensive phylogenetic classification of the kingdom Fungi is proposed, with reference to recent molecular phylogenetic analyses, and with input from diverse members of the fungal taxonomic community. The classification includes 195 taxa, down to the level of order, of which 16 are described or validated here: Dikarya subkingdom nov.; Chytridiomycota, Neocallimastigomycota phyla nov.; Monoblepharidomycetes, Neocallimastigomycetes class. nov.; Eurotiomycetidae, Lecarioromycetidae, Mycocaliciomycetidae subclass. nov.; Acarosporales, Corticiales, Baeomycetales, Candelariales, Gloeophyllales, Melanosporales, Trechisporales, Umbilicariales ords. nov. The clade containing Ascomycota and Basidiomycota is classified as subkingdom Dikarya, reflecting the putative synapomorphy of dikaryotic hyphae. The most dramatic shifts in the classification relative to previous works concern the groups that have traditionally been included in the Chytridiomycota and Zygomycota. The Chytridiomycota is retained in a restricted sense, with Blastocladiomycota and Neocallimastigomycota representing segregate phyla of flagellated Fungi. Taxa traditionally placed in Zygomycota are distributed among Glomeromycota and several subphyla incertae sedis, including Mucoromycotina, Entomophthoromycotina, Kickxellomycotina, and Zoopagomycotiria. Microsporidia are included in the Fungi, but no further subdivision of the group is proposed. Several genera of 'basal' Fungi of uncertain position are not placed in any higher taxa, including Basidiobolus, Caulochytrium, Olpidium, and Rozella. (c) 2007 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.
|
|
| 5. |
- Li, Dai-Qing, et al.
(författare)
-
Suppression of sulfonylurea- and glucose-induced insulin secretion in vitro and in vivo in mice lacking the chloride transport protein ClC-3.
- 2009
-
Ingår i: Cell metabolism. - : Elsevier BV. - 1932-7420 .- 1550-4131. ; 10:4, s. 309-15
-
Tidskriftsartikel (refereegranskat)abstract
- Priming of insulin secretory granules for release requires intragranular acidification and depends on vesicular Cl(-)-fluxes, but the identity of the chloride transporter/ion channel involved is unknown. We tested the hypothesis that the chloride transport protein ClC-3 fulfills these actions in pancreatic beta cells. In ClC-3(-/-) mice, insulin secretion evoked by membrane depolarization (high extracellular K(+), sulfonylureas), or glucose was >60% reduced compared to WT animals. This effect was mirrored by a approximately 80% reduction in depolarization-evoked beta cell exocytosis (monitored as increases in cell capacitance) in single ClC-3(-/-) beta cells, as well as a 44% reduction in proton transport across the granule membrane. ClC-3 expression in the insulin granule was demonstrated by immunoblotting, immunostaining, and negative immuno-EM in a high-purification fraction of large dense-core vesicles (LDCVs) obtained by phogrin-EGFP labeling. The data establish the importance of granular Cl(-) fluxes in granule priming and provide direct evidence for the involvement of ClC-3 in the process.
|
|
| 6. |
- Yang, B., et al.
(författare)
-
Fabrication and Characterization of Small Optical Ridge Waveguides Based on SU-8 Polymer
- 2009
-
Ingår i: Journal of Lightwave Technology. - : Institute of Electrical and Electronics Engineers (IEEE). - 0733-8724 .- 1558-2213. ; 27:18, s. 4091-4096
-
Tidskriftsartikel (refereegranskat)abstract
- Small SU-8 ridge optical waveguides with an air cladding and a SiO2 buffer on Si substrate have been realized by using a direct ultraviolet (UV) photolithography technology. The propagation loss measured by the cut-back method is about 0.1 dB/mm (@1550 nm) when the core width is 2.8 mu m. The bending losses of the present SU-8 optical ridge waveguides are also characterized. The measured results show that the bending loss decreases exponentially as the bending radius increases and the total loss can be reduced effectively by introducing an appropriate offset between two connected sections with different curvatures. A small bending radius (as small as 75 mu m) is still allowed for the requirement of a small bending loss (< 0.1 dB) when an offset of 0.1 mu m is introduced. Finally, by using this kind of waveguide, a small 1 x 2 Y-branch power splitter is fabricated and characterized.
|
|
| 7. |
- Yang, L., et al.
(författare)
-
Characteristic analysis of tapered lens fibers for light focusing and butt-coupling to a silicon rib waveguide
- 2009
-
Ingår i: Applied Optics. - 1559-128X .- 2155-3165. ; 48:4, s. 672-678
-
Tidskriftsartikel (refereegranskat)abstract
- The characteristics of tapered lens fibers (TLFs) are analyzed by using a finite-difference time-domain (FDTD) method. Two types of TLFs are considered, namely a tape red-cladding TLF and a tapered-core TLF The radial FDTD method is first used to simulate light focusing for these two types of TLFs. It is shown that the tapered-core TLF has a smaller focus spot size and a larger transmission loss than the tapered-cladding TLF. The butt-coupling between a TLF of either type and a Si rib waveguide is then simulated by a three-dimensional FDTD method. The tapered-core TLF has a smaller coupling loss to the Si rib waveguide but a similar total loss (the sum of the coupling loss and the transmission loss), as compared with the tapered-cladding TLF
|
|
| 8. |
- Yang, L., et al.
(författare)
-
Compact 2x2 tapered multimode interference couplers based on SU-8 polymer rectangular waveguides
- 2008
-
Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 93:20
-
Tidskriftsartikel (refereegranskat)abstract
- A 2x2 tapered multimode interference (MMI) coupler is designed and fabricated by using air-cladded SU-8 rectangular waveguide, which is effective in reducing the device size and improving the self-imaging quality. The parabolically tapered MMI section is used to reduce further the size of the MMI coupler. A compact 2x2 coupler with a total MMI size of about 5.3x34.2 mu m(2) is demonstrated and characterized. The measurement results show that the fabricated 2x2 MMI coupler has relatively small excess loss and nonuniformity for both polarizations in a broad wavelength range (from 1480 to 1630 nm).
|
|
| 9. |
- Zhang, Hongyuan, et al.
(författare)
-
Asynchronous interference mitigation in cooperative base station systems
- 2008
-
Ingår i: IEEE Transactions on Wireless Communications. - 1536-1276. ; 7:1, s. 155-165
-
Tidskriftsartikel (refereegranskat)abstract
- Cooperative transmission by base stations (BSs) can significantly improve the spectral efficiency of multiuser, multicell, multiple input multiple output (MIMO) systems. We show that contrary to what is often assumed in the literature, the multiuser interference in such systems is fundamentally asynchronous. Intuitively, perfect timing-advance mechanisms can at best only ensure that the desired signal components - but not also the interference components - are perfectly aligned at their intended mobile stations. We develop an accurate mathematical model for the asynchronicity, and show that it leads to a significant performance degradation of existing designs that ignore the asynchronicity of interference. Using three previously proposed linear precoding design methods for BS cooperation, we develop corresponding algorithms that are better at mitigating the impact of the asynchronicity of the interference. Furthermore, we also address timing-advance inaccuracies (jitter), which are inevitable in a practical system. We show that using jitter-statistics-aware precoders can mitigate the impact of these inaccuracies as well. The insights of this paper are critical for the practical implementation of BS cooperation in multiuser MIMO systems, a topic that is typically oversimplified in the literature.
|
|
| 10. |
|
|
