Restriction on the energy and luminosity of e+e- storage rings due to beamstrahlung

The role of beamstrahlung in high-energy e+e- storage-ring colliders (SRCs) is examined. Particle loss due to the emission of single energetic beamstrahlung photons is shown to impose a fundamental limit on SRC luminosities at energies 2E_0 >~ 140 GeV for head-on collisions and 2E_0 >~ 40 GeV for crab-waist collisions. With beamstrahlung taken into account, we explore the viability of SRCs in the E_0=240-500 GeV range, which is of interest in the precision study of the Higgs boson. At 2E_0=240 GeV, SRCs are found to be competitive with linear colliders; however, at 2E_0=400-500 GeV, the attainable SRC luminosity would be a factor 15-25 smaller than desired.Comment: Latex, 5 pages. v2 differs only by minor changes is abstract and introduction, one reference is added. v3 corresponds to the paper published in PR

Nitrogen mineralization and gaseous nitrogen losses from waterlogged and drained organic soils in a black alder (<i>Alnus glutinosa</i> (L.) Gaertn.) forest

Black alder (<i>Alnus glutinosa</i> (L.) Gaertn.) forests on peat soils have been reported to be hotspots for high nitrous oxide (N₂O) losses. High emissions may be attributed to alternating water tables of peatlands and to the incorporation of high amounts of easily decomposable nitrogen (N) into the ecosystem by symbiotic dinitrogen (N₂)-fixation of alder trees. Our study addressed the question to what extent drainage enhances the emissions of N₂O from black alder forests and how N turnover processes and physical factors influence the production of N₂O and total denitrification. The study was conducted in a drained black alder forest with variable groundwater tables at a southern German fen peatland. Fluxes of N₂O were measured using the closed chamber method at two drained sites (D-1 and D-2) and one undrained site (U). Inorganic N contents and net N mineralization rates (NNM) were determined. Additionally a laboratory incubation experiment was carried out to investigate greenhouse gas and N₂ fluxes at different temperature and soil moisture conditions. Significantly different inorganic N contents and NNM rates were observed, which however did not result in significantly different N₂O fluxes in the field but did in the laboratory experiment. N₂O fluxes measured were low for all sites, with total annual emissions of 0.51 ± 0.07 (U), 0.97 ± 0.13 (D-1) and 0.93 ± 0.08 kg N₂O–N ha⁻¹ yr^&minus;1 (D-2). Only 37% of the spatiotemporal variation in field N₂O fluxes could be explained by peat temperature and groundwater level, demonstrating the complex interlinking of the controlling factors for N₂O emissions. However, temperature was one of the key variables of N₂O fluxes in the incubation experiment conducted. Increasing soil moisture content was found to enhance total denitrification losses during the incubation experiment, whereas N₂O fluxes remained constant. At the undrained site, permanently high groundwater level was found to prevent net nitrification, resulting in a limitation of available nitrate (NO₃^&minus;) and negligible gaseous N losses. N₂O flux rates that were up to four times higher were measured in the incubation experiment. They reveal the potential of high N₂O losses under changing soil physical conditions at the drained alder sites. The high net nitrification rates observed and high NO₃^&minus; contents bear the risk of considerable NO₃^&minus; leaching at the drained sites

Irradiation study of a fully monolithic HV-CMOS pixel sensor design in AMS 180 nm

High-Voltage Monolithic Active Pixel Sensors (HV-MAPS) based on the 180 nm HV-CMOS process have been proposed to realize thin, fast and highly integrated pixel sensors. The MuPix7 prototype, fabricated in the commercial AMS H18 process, features a fully integrated on-chip readout, i.e. hit-digitization, zero suppression and data serialization. It is the first fully monolithic HV-CMOS pixel sensor that has been tested for the use in high irradiation environments like HL-LHC. We present results from laboratory and test beam measurements of MuPix7 prototypes irradiated with neutrons (up to $5.0\cdot10^{15}{\,\rm{n}_{\rm{eq}}/cm^2}$) and protons (up to $7.8\cdot 10^{15} \,\rm{protons}/cm^2$) and compare the performance with non-irradiated sensors. Efficiencies well above 90 % at noise rates below 200 Hz per pixel are measured. A time resolution better than 22 ns is measured for all tested settings and sensors, even at the highest irradiation fluences. The data transmission at 1.25 Gbit/s and the on-chip PLL remain fully functional

Measurement of the Blackbody Radiation Shift of the 133Cs Hyperfine Transition in an Atomic Fountain

We used a Cs atomic fountain frequency standard to measure the Stark shift on the ground state hyperfine transiton frequency in cesium (9.2 GHz) due to the electric field generated by the blackbody radiation. The measures relative shift at 300 K is -1.43(11)e-14 and agrees with our theoretical evaluation -1.49(07)e-14. This value differs from the currently accepted one -1.69(04)e-14. The difference has a significant implication on the accuracy of frequency standards, in clocks comparison, and in a variety of high precision physics tests such as the time stability of fundamental constants.Comment: 4 pages, 2 figures, 2 table

Modification of Kawai model about the mixing of the pseudoscalar mesons

The Kawai model describing the glueball-quarkonia mixing is modified. The mixing of $\eta$, $\eta^\prime$ and $\eta(1410)$ is re-investigated based on the modified Kawai model. The glueball-quarkonia content of the three states is determined from a fit to the data of the electromagnetic decays involving $\eta$, $\eta^\prime$. Some predictions about the electromagnetic decays involving $\eta(1410)$ are presented.Comment: revtex 8 page

Design and Construction of a 50m Single Span Ultra High Performance Ductile Concrete Composite Road Bridge

A single span 50m long prestressed road bridge was constructed under Public Works&nbsp;Department in the State of Negeri Sembilan, Malaysia contract recently. The bridge was&nbsp;constructed at a small village, Kampung Linsum, crossing a river, Sungai Linggi. To date,&nbsp;this bridge is the Malaysia first and may also be the world longest composite road bridge&nbsp;which made from ultra-high performance ductile concrete (UHPdC). This paper presents the&nbsp;feature of the UHPdC precast girder; brief in-sight of the manufacturing of the girder; the&nbsp;construction sequence of the bridge; the design method and lastly the environmental impact&nbsp;calculation. The midspan deflections of the bridge at different construction history were&nbsp;compared against the collected field data and it showed that the calculated values generally&nbsp;agree well with the field data

Open-domain topic identification of out-of-domain utterances using Wikipedia

Users of spoken dialogue systems (SDS) expect high quality interactions across a wide range of diverse topics. However, the implementation of SDS capable of responding to every conceivable user utterance in an informative way is a challenging problem. Multi-domain SDS must necessarily identify and deal with out-of-domain (OOD) utterances to generate appropriate responses as users do not always know in advance what domains the SDS can handle. To address this problem, we extend the current state-of-the-art in multi-domain SDS by estimating the topic of OOD utterances using external knowledge representation from Wikipedia. Experimental results on real human-to-human dialogues showed that our approach does not degrade domain prediction performance when compared to the base model. But more significantly, our joint training achieves more accurate predictions of the nearest Wikipedia article by up to about 30% when compared to the benchmarks

Quark-Resonance model

We construct an effective Lagrangian for low energy hadronic interactions through an infinite expansion in inverse powers of the low energy cutoff $\Lambda_\chi$ of all possible chiral invariant non-renormalizable interactions between quarks and mesons degrees of freedom. We restrict our analysis to the leading terms in the $1/N_c$ expansion. The effective expansion is in (\mu^2/\cutoff^2 )^P \ln (\cutoff^2/\mu^2 )^Q. Concerning the next-to-leading order, we show that, while the pure \mu^2/\cutoff^2 corrections cannot be traced back to a finite number of non renormalizable interactions, those of order (\mu^2/\cutoff^2 ) \ln (\cutoff^2/\mu^2 ) receive contributions from a finite set of 1/\cutoff^2 terms. Their presence modifies the behaviour of observable quantities in the intermediate $Q^2$ region. We explicitely discuss their relevance for the two point vector currents Green's function.Comment: 41 pages, 11 figures, preprint ROM2F 93/3