Study of emittance blow-up sources between the PS booster and the 26 GeV PS

The tight transverse emittance budget for the bright beams foreseen for the LHC era demands that all sources of emittance blow-up in the injector chain are reduced to a minimum. A critical region is the transfer between the PS Booster (PSB) and the 26 GeV PS. The four rings of the PSB run with RF harmonic one, and for the LHC beam the PS will be filled with eight bunches originating from two consecutive PSB cycles. Thus, each bunch will be different and has to be individually treated. The present recombination scheme introduces an important difference in lattice parameters between the bunches from different rings. The difference between the bunches would, if left uncorrected, result in a substantial emittance blow-up. Several possible improvements of the recombination stage have been studied, including magnet shims, correction quadrupoles and an RF quadrupole magnet. To complement the theoretical studies, the contribution of mismatch and missteering to the emittance blow-up have been measured using a LHC-type beam, measuring the emittance in the PS with a wire-grid and fast wire-scanners. Results of the calculation and the measurements will be discussed and a strategy to minimise the blow-up will be indicated

The Power Spectrum of Mass Fluctuations Measured from the Lyman-alpha Forest at Redshift z=2.5

We measure the linear power spectrum of mass density fluctuations at redshift z=2.5 from the \lya forest absorption in a sample of 19 QSO spectra, using the method introduced by Croft et al. (1998). The P(k) measurement covers the range 2\pi/k ~ 450-2350 km/s (2-12 comoving \hmpc for \Omega=1). We examine a number of possible sources of systematic error and find none that are significant on these scales. In particular, we show that spatial variations in the UV background caused by the discreteness of the source population should have negligible effect on our P(k) measurement. We obtain consistent results from the high and low redshift halves of the data set and from an entirely independent sample of nine QSO spectra with mean redshift z=2.1. A power law fit to our measured P(k) yields a logarithmic slope n=-2.25 +/- 0.18 and an amplitude \Delta^2(k_p) = 0.57^{+0.26}_{-0.18}, where $\Delta^2$ is the contribution to the density variance from a unit interval of lnk and k_p=0.008 (km/s)^{-1}. Direct comparison of our mass P(k) to the measured clustering of Lyman Break Galaxies shows that they are a highly biased population, with a bias factor b~2-5. The slope of the linear P(k), never previously measured on these scales, is close to that predicted by models based on inflation and Cold Dark Matter (CDM). The P(k) amplitude is consistent with some scale-invariant, COBE-normalized CDM models (e.g., an open model with \Omega_0=0.4) and inconsistent with others (e.g., \Omega=1). Even with limited dynamic range and substantial statistical uncertainty, a measurement of P(k) that has no unknown ``bias factors'' offers many opportunities for testing theories of structure formation and constraining cosmological parameters. (Shortened)Comment: Submitted to ApJ, 27 emulateapj pages w/ 19 postscript fig

Beams in the CERN PS complex after the RF upgrades for LHC

In preparation for the Large Hadron Collider (LHC), extensive modifications have been made to the RF equipment of the PS Booster (PSB) and of the PS during the winter shut down 97-98. Low-frequency RF systems (0.6 - 1.8 MHz and 1.2 - 3.9 MHz) have been installed in the PSB and fixed frequency (40 and 80 MHz) systems in the PS. The longitudinal characteristics of all beams are changed to make the best use of the new capabilities. This paper summarises the characteristics of the new equipment and describes the RF gymnastics used to generate the various beams. The performances achieved so far ar e reported and compared to former results. Future plans are sketched

Proteins in Ionic Liquids: Reactions, Applications, and Futures

Biopolymer processing and handling is greatly facilitated by the use of ionic liquids, given the increased solubility, and in some cases, structural stability imparted to these molecules. Focussing on proteins, we highlight here not just the key drivers behind protein-ionic liquid interactions that facilitate these functionalities, but address relevant current and potential applications of protein-ionic liquid interactions, including areas of future interest

List coloring in the absence of a linear forest.

The k-Coloring problem is to decide whether a graph can be colored with at most k colors such that no two adjacent vertices receive the same color. The Listk-Coloring problem requires in addition that every vertex u must receive a color from some given set L(u)⊆{1,…,k}. Let Pn denote the path on n vertices, and G+H and rH the disjoint union of two graphs G and H and r copies of H, respectively. For any two fixed integers k and r, we show that Listk-Coloring can be solved in polynomial time for graphs with no induced rP1+P5, hereby extending the result of Hoàng, Kamiński, Lozin, Sawada and Shu for graphs with no induced P5. Our result is tight; we prove that for any graph H that is a supergraph of P1+P5 with at least 5 edges, already List 5-Coloring is NP-complete for graphs with no induced H

Transverse Performance of the Proton Beam Delivered by the CERN PS Complex for the Future LHC

The performance of the CERN LHC will depend heavily on the high-brightness beam delivered by the injector chain. In 1999, after completion of the programme of hardware upgrades of the PS Complex, a major effort was devoted to producing a proton beam with the nominal transverse characteristics foreseen for LHC operation. This paper focuses on the different beam dynamics issues encountered during the setting up of such a beam, in the Linac2, the PS-Booster (PSB), the PS and the TT2 transfer line to the SPS. During the setting-up, single-particle issues, like stop-band compensation, correction of injection oscillations during the double-batch injection process, and the correction of the high-energy closed orbit in the PS, were addressed. Furthermore, collective effects, such as high-order head-tail instabilities induced by the resistive-wall impedance, were observed and cured. The compensation of these harmful phenomena permitted to achieve the goal, namely the generation of small transverse beam emittances and their conservation along the chain of different machines

Compressive stenosis of the left hepatic vein as a pathogenesis of postresectional liver failure: a case report

<p>Abstract</p> <p>Introduction</p> <p>Postresectional liver failure (PLF) is a devastating and fatal complication of major hepatic resection, and we do not have a full understanding of the pathogenic mechanisms involved. No reliable treatment other than liver transplantation currently exists for PLF.</p> <p>Case presentation</p> <p>A 46-year-old Japanese man experienced PLF after an extended right hepatectomy for liver malignancy. Seven months after surgery, the patient's Model for End-Stage Liver Disease (MELD) score had reached 23. Doppler ultrasound study and three-dimensional computed tomography images showed a stenosed left hepatic vein compressed by surrounding hypertrophied hepatic parenchyma. Transluminal balloon angioplasty and stent placement therapy were conducted eight months after surgery. The pressure gradient between the hepatic vein and right atrium decreased from 13 to 3 mmHg after stent placement. Thereafter, the patient recovered.</p> <p>Conclusion</p> <p>Hepatic venous compression by surrounding hypertrophied hepatic parenchyma might, at least in part, be associated with the occurrence of PLF. Surgeons should bear this possibility in mind when confronted with cases of PLF, as early diagnosis and stent placement improves patients' chances of recovery.</p