| 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. |
- Aamodt, K., et al.
(författare)
-
The ALICE experiment at the CERN LHC
- 2008
-
Ingår i: Journal of Instrumentation. - 1748-0221. ; 3:S08002
-
Forskningsöversikt (refereegranskat)abstract
- ALICE (A Large Ion Collider Experiment) is a general-purpose, heavy-ion detector at the CERN LHC which focuses on QCD, the strong-interaction sector of the Standard Model. It is designed to address the physics of strongly interacting matter and the quark-gluon plasma at extreme values of energy density and temperature in nucleus-nucleus collisions. Besides running with Pb ions, the physics programme includes collisions with lighter ions, lower energy running and dedicated proton-nucleus runs. ALICE will also take data with proton beams at the top LHC energy to collect reference data for the heavy-ion programme and to address several QCD topics for which ALICE is complementary to the other LHC detectors. The ALICE detector has been built by a collaboration including currently over 1000 physicists and engineers from 105 Institutes in 30 countries, Its overall dimensions are 16 x 16 x 26 m(3) with a total weight of approximately 10 000 t. The experiment consists of 18 different detector systems each with its own specific technology choice and design constraints, driven both by the physics requirements and the experimental conditions expected at LHC. The most stringent design constraint is to cope with the extreme particle multiplicity anticipated in central Pb-Pb collisions. The different subsystems were optimized to provide high-momentum resolution as well as excellent Particle Identification (PID) over a broad range in momentum, up to the highest multiplicities predicted for LHC. This will allow for comprehensive studies of hadrons, electrons, muons, and photons produced in the collision of heavy nuclei. Most detector systems are scheduled to be installed and ready for data taking by mid-2008 when the LHC is scheduled to start operation, with the exception of parts of the Photon Spectrometer (PHOS), Transition Radiation Detector (TRD) and Electro Magnetic Calorimeter (EMCal). These detectors will be completed for the high-luminosity ion run expected in 2010. This paper describes in detail the detector components as installed for the first data taking in the summer of 2008.
|
|
| 3. |
- Hwang, J.W., et al.
(författare)
-
Effect of COD/SO42- ratio and Fe(II) under the variable hydraulic retention time (HRT) on fermentative hydrogen production
- 2009
-
Ingår i: Water Research. - : Elsevier BV. - 0043-1354 .- 1879-2448. ; 43, s. 3525-3533
-
Tidskriftsartikel (refereegranskat)abstract
- The effect of chemical oxygen demand/sulfate (COD/SO42−) ratio on fermentative hydrogen production using enriched mixed microflora has been studied. The chemostat system maintained with a substrate (glucose) concentration of 15 g COD L−1 exhibited stable H2 production at inlet sulfate concentrations of 0–20 g L−1 during 282 days. The tested COD/SO42− ratios ranged from 150 to 0.75 (with control) at pH 5.5 with hydraulic retention time (HRT) of 24, 12 and 6 h. The hydrogen production at HRT 6 h and pH 5.5 was not influenced by decreasing the COD/SO42− ratio from 150 to 15 (with control) followed by noticeable increase at COD/SO42− ratios of 5 and 3, but it was slightly decreased when the COD/SO42− ratio further decreased to 1.5 and 0.75. These results indicate that high sulfate concentrations (up to 20,000 mg L−1) would not interfere with hydrogen production under the investigated experimental conditions. Maximum hydrogen production was 2.95, 4.60 and 9.40 L day−1 with hydrogen yields of 2.0, 1.8 and 1.6 mol H2 mol−1 glucose at HRTs of 24, 12 and 6 h, respectively. The volatile fatty acid (VFA) fraction produced during the reaction was in the order of butyrate > acetate > ethanol > propionate in all experiments. Fluorescence In Situ Hybridization (FISH) analysis indicated the presence of Clostridium spp., Clostridium butyricum, Clostridium perfringens andRuminococcus flavefaciens as hydrogen producing bacteria (HPB) and absence of sulfate reducing bacteria (SRB) in our study.
|
|
| 4. |
- Kaput, J, et al.
(författare)
-
The case for strategic international alliances to harness nutritional genomics for public and personal health
- 2005
-
Ingår i: The British journal of nutrition. - : Cambridge University Press (CUP). - 0007-1145 .- 1475-2662. ; 94:5, s. 623-632
-
Tidskriftsartikel (refereegranskat)abstract
- Nutrigenomics is the study of how constituents of the diet interact with genes, and their products, to alter phenotype and, conversely, how genes and their products metabolise these constituents into nutrients, antinutrients, and bioactive compounds. Results from molecular and genetic epidemiological studies indicate that dietary unbalance can alter gene–nutrient interactions in ways that increase the risk of developing chronic disease. The interplay of human genetic variation and environmental factors will make identifying causative genes and nutrients a formidable, but not intractable, challenge. We provide specific recommendations for how to best meet this challenge and discuss the need for new methodologies and the use of comprehensive analyses of nutrient–genotype interactions involving large and diverse populations. The objective of the present paper is to stimulate discourse and collaboration among nutrigenomic researchers and stakeholders, a process that will lead to an increase in global health and wellness by reducing health disparities in developed and developing countries.
|
|
| 5. |
|
|
| 6. |
- Dogiel, V. A., et al.
(författare)
-
In-situ acceleration of subrelativistic electrons in the Coma halo and the halo’s influence on the Sunyaev-Zeldovich effect
- 2007
-
Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 461:2, s. 433-443
-
Tidskriftsartikel (refereegranskat)abstract
- Aims. The stochastic acceleration of subrelativistic electrons from a background plasma is studied in order to find a possible explanation of the hard X-ray emission detected from the Coma cluster. Methods. We calculate the necessary energy supply as a function of the plasma temperature and of the electron energy, and we show that, for the same value of the hard X-ray flux, the energy supply changes gradually from its high value for the case when emitting particle are non-thermal to lower values whenthe electrons are thermal. The kinetic equations we use include terms describing particle thermalization as well as momentum diffusion due to the Fermi IIacceleration. Results. We show that the temporal evolution of the particle distribution function has, at its final stationary stage, a rather specific form. This distribution function cannot be described by simple exponential or power-law expressions. A broad transfer region is formed by Coulomb collisions at energies betweenthe Maxwellian and power-law parts of the distribution functions. In this region the radiative lifetime of a single quasi-thermal electron differs greatly from thelifetime of the distribution function as a whole. For a plasma temperature of 8 keV, the particles emitting bremsstrahlung at 20-80 keV lie in this quasi-thermal regime. We show that the energy supply required by quasi-thermal electrons to produce the observed hard X-ray flux from Coma is one or two orders ofmagnitude smaller than the value derived from the assumption of a nonthermal origin of the emitting particles. This result may solve the problem of rapid cluster overheating by nonthermal electrons raised by Petrosian (2001): while Petrosian's estimates are correct for nonthermal particles, they are inapplicablein the quasi-thermal range. We finally analyze the change in Coma's Sunyaev-Zeldovich effect caused by the implied distortions of the Maxwellian spectrumof electrons, and we show that evidence for the acceleration of subrelativistic electrons can, in principle, be derived from detailed spectral measurements.
|
|
| 7. |
- Grim, Jonathan E., et al.
(författare)
-
Isoform- and cell cycle-dependent substrate degradation by the Fbw7 ubiquitin ligase
- 2008
-
Ingår i: Journal of Cell Biology. - : Rockefeller University Press. - 0021-9525 .- 1540-8140. ; 181:6, s. 913-920
-
Tidskriftsartikel (refereegranskat)abstract
- The SCF(FBW7) ubiquitin ligase degrades proteins involved in cell division, growth, and differentiation and is commonly mutated in cancers. The Fbw7 locus encodes three protein isoforms that occupy distinct subcellular localizations, suggesting that each has unique functions. We used gene targeting to create isoform-specific Fbw7-null mutations in human cells and found that the nucleoplasmic Fbw7alpha isoform accounts for almost all Fbw7 activity toward cyclin E, c-Myc, and sterol regulatory element binding protein 1. Cyclin E sensitivity to Fbw7 varies during the cell cycle, and this correlates with changes in cyclin E-cyclin-dependent kinase 2 (CDK2)-specific activity, cyclin E autophosphorylation, and CDK2 inhibitory phosphorylation. These data suggest that oscillations in cyclin E-CDK2-specific activity during the cell cycle regulate the timing of cyclin E degradation. Moreover, they highlight the utility of adeno-associated virus-mediated gene targeting in functional analyses of complex loci.
|
|
| 8. |
- Hwang, K.W., et al.
(författare)
-
Observation of difference in the size distribution of carbon and major inorganic compounds of atmospheric aerosols after the long-range transport between the selected days of winter and summer
- 2008
-
Ingår i: Atmospheric Environment. - : Elsevier BV. - 1352-2310 .- 1873-2844. ; 42:5, s. 1057-1063
-
Tidskriftsartikel (refereegranskat)abstract
- This paper presents the results from a study conducted in two urban areas in Korea to compare the size distributions of atmospheric aerosols, focusing on carbonaceous and certain major inorganic compounds, after long-range transport between selected days in winter and summer. Size segregated aerosols were sampled for 3 consecutive days each in February and July, 2004, and were analyzed to obtain the 24-h averaged concentrations of total mass, elemental carbon, organic carbon, nitrate, and sulfate. Backward trajectories from the receptor site on the sampling days were calculated to estimate the elapsed time for the air parcel to travel between Wonju and the Seoul metropolitan area. The averaged elapsed time on the sampling days was 3–12 h in the winter and 10–19 h in the summer. The enrichment of fine particles as expressed in particulate matter (PM)2/(PM10–PM2) was higher in the summer as compared to that in the winter. Size-fractionized concentration ratios of the organic to the elemental carbon at Wonju were two times as high as those at Seoul except for the particles with size <0.5 μm. This increasing trend was in proportional to the length of the elapsed time during the summer. Ultrafine particles in the summer were further enriched in carbon compounds, particularly in organic carbons and those in winter more enriched in the sulfates and nitrates. The mass fractions of organic carbon, elemental carbon, sulfate and nitrate became more significant with the decrease in the particle size.
|
|
| 9. |
- Mouyen, Maxime, 1982, et al.
(författare)
-
Expected temporal absolute gravity change across the Taiwanese Orogen, a modeling approach
- 2009
-
Ingår i: Journal of Geodynamics. - : Elsevier BV. - 0264-3707. ; 48:3-5
-
Tidskriftsartikel (refereegranskat)abstract
- The island of Taiwan is located on the convergent boundary between the Philippine Sea plate and the Chinese continental margin. It offers very active mountain building and collapsing processes well illustrated by the rugged topography, rapid uplift and denudation, young tectonic landforms, active faulting and numerous earthquakes. In this paper, using simple models, we have estimated vertical movements and associated absolute gravity variations which can be expected along a profile crossing the southern part of the island and probably suffering the highest rates of rising. The two different tectonic styles proposed for the island, thin-skinned and thick-skinned, were taken into account. Horizontal and vertical movements were modeled by an elastic deformation code. Gravity variations due to these deformations are then modeled at a second step. They are dominated by plate and free-air effects, i.e. elevation of the topography, with several μGal yr-1. By comparison, gravity changes generated by mass transfers are weak: maximum 0.1 μGal yr-1 with the thin-skinned tectonic and 0.3 μGal yr-1 with the thick-skinned tectonic. Though elastic rheology has limitations, this modeling offers interesting results on what gravity signal can be expected from the AGTO project (Absolute Gravity in the Taiwanese Orogen), which proposes to study the dynamic of these mountain ranges using absolute gravimetry (AG) and also including relative gravimetry (RG) and GPS measurements.
|
|
| 10. |
- Wu, W. C., et al.
(författare)
-
Design, Fabrication, and Characterization of Novel Vertical Coaxial Transitions for Flip-Chip Interconnects
- 2009
-
Ingår i: IEEE Transactions on Advanced Packaging. - 1521-3323. ; 32:2, s. 362-371
-
Tidskriftsartikel (refereegranskat)abstract
- In this paper, a novel transition design using vertical "coaxial transition" for coplanar waveguide (CPW-to-CPW) flip-chip interconnect is proposed and presented for the first time. The signal continuity is greatly improved since the coaxial-type transition provides more return current paths compared to the conventional transition in the flip-chip structure. The proposed coaxial transition structure shows a real coaxial property from the 3-D electromagnetic wave simulation results. The design rules for the coaxial transition are presented in detail with the key parameters of the coaxial transition structure discussed. For demonstration, the back-to-back flip-chip interconnect structures with the vertical coaxial transitions have been successfully fabricated and characterized. The demonstrated interconnect structure using the coaxial transition exhibits the return loss below 25 dB and the insertion loss within 0.4 dB from dc to 40 GHz. Furthermore, the measurement and simulation results show good agreement. The novel coaxial transition demonstrates excellent interconnect performance for flip-chip interconnects and shows great potential for flip-chip packaging applications at millimeter waves.
|
|
