For the beam-beam phenomenon in e + e " colliding rings, a simple model is presented, which illustrates several common features of the observed phenomenon (a blowup of one beam above a certain current, the unavoidable beam-beam limit, etc.). The tune-shift limit is given as a function only of betatron tune and radiation damping rate per collision point. This implies the universality of the phenomenon.PACS numbers: 29.20.Dh In all high-energy e + e~ colliding storage rings, it is commonly observed 1 that although the luminosity L increases as I 1 (I being beam current) for small /, L becomes proportional only to / when / exceeds a certain critical value. This is equivalent to the saturation of the beam-beam parameter 1 (£). Remarkably, 2 the saturated value (£oo) is almost universally 0.05, although the appearances of the phenomenon are quite complicated.Since the achievable L is limited by £«>, understanding of the phenomenon has been one of the most important problems. In particular, the saturation mechanism of £ is little understood, though it is clearly seen in a numerical multiparticle tracking 3 (MPT). It is almost certain 1 that the beam height increases in proportion to /; there seems, however, to be no theoretical explanation of it.We will present a simple model that explains the saturation and related universal phenomena. Let us consider a ring with N s interaction points (IP's) and N s /2 bunches of equal intensity in each beam. To make our model simple, we use a flat-beam 4 limit (FBL), where the horizontal motion can reasonably be assumed to be unaffected, and assume that coherent dipole motion is stable and ignorable. The next plausible assumption is that the particle distribution giving the beam-beam force at an IP can be treated as Gaussian.We have now only to study the motion of a particle in a bunch in the vertical direction y. The motion can be described by successive operations of the following three mappings: O (oscillation), Y\ -Y x andVi-Y 2 + G(Yi), G(r) = -fcerf[r/(2Af 1 ) 1/2 ]; R (radiation), Y[=Y { and Y' 2 =^2+ {(1 ~X 2 )e y } 1/2 r. Here Y\=yl^[fT y and K 2 = {a y y +fi y y')l^[Wy are tne canonical variables defined in terms of nominal Twiss parameters, Afi is the average of Y\ of the partner bunch under collision, fi (=2/rv) is the betatron phase advance per IP, A, is the damping ratio defined by ?t=exp( -28) with 8 being the damping decrement 5 [(revolution time)/(betatron damping time per IP)], e y is the nominal vertical emittance, and r is a noise with unit standard deviation. Lastly K = 2n 3/2^/ £ y rj defines the vertical beam-beam force averaged over the horizontal direction, where r\ is the nominal beam-beam parameter, Nr P 2ny 1/2 1 Ux£v) 1/2 'Here TV is the number of particles in the partner bunch, r e the classical electron radius, y the relativistic Lorentz factor, p®,y the nominal p function at an IP, and s x the nominal horizontal emittance. We have treated the effect of radiation as if it works locally. Since essentially the effect belongs to linear dynamics, this ...

Fungal isolates from gray leaf spot on perennial ryegrass (prg isolates) were characterized by DNA analyses, mating tests, and pathogenicity assays. All of the prg isolates were interfertile with Triticum isolates and clustered into the crop isolate group (CC group) on a dendrogram constructed from rDNA-internal transcribed spacer 2 sequences. Since the CC group corresponded to a newly proposed species, Magnaporthe oryzae, all of the prg isolates were designated M. oryzae. However, DNA fingerprinting with MGR586, MGR583, and Pot2 showed that the prg isolates are divided into two distinct populations, i.e., TALF isolates and WK isolates. The TALF isolates were virulent only on Lolium species, whereas the WK isolates were less specific, suggesting that gray leaf spot can be caused not only by Lolium-specific isolates but also by less specific isolates. We designated the TALF isolates as Lolium pathotype. The TALF isolates showed diverse karyotypes in spite of being uniform in DNA fingerprints, suggesting that theyare unstable in genome organization.

Pyricularia isolates from various host plants were subjected to a multilocus phylogenetic analysis based on rDNA-ITS, actin, beta-tubulin, and calmodulin loci. A combined gene tree resolved seven groups with 100% BS support, suggesting that they are monophyletic groups supported concordantly by all four loci. By incorporating biological and morphological species criteria, each of the seven groups was considered to be a current species. However, phylogenetic relationships among these species were unresolved in the single-gene trees and in the combined tree. Furthermore, the transition from concordance to conflict occurred more than once in the combined gene tree. They were interpreted by assuming that Pyricularia has evolved through repeated species radiation. The transition point other than the current species limit was considered to be the limit of the former species.

The equilibrium state of an electron in a storage ring can be described most accurately by the envelope matrix, as long as the electron motion is hnear. The equilibrium envelope can be calculated in the same way as the equilibrium barycenter (closed orbit). This is suited for accurate numerical calculations. The "emittances" can be extracted from the envelope as approximate quantities. The radiation integrals, which express the emittances in terms of Twiss parameters, dispersions, and other optical parameters, are extended to cover general 6X6 dynamics. Without any coupling between modes, these reduce to those of Sands.

Summary Background Asthma is a chronic airway inflammatory disease; however, the molecular mechanisms that underlie asthma exacerbation are only partially understood. Objective To identify gene expression signatures that reflect the acute exacerbation of asthma, we examined the differential expression of genes during asthma exacerbation and stable condition by using microarray analysis. Methods The subjects were mite‐sensitive asthmatic children and non‐asthmatic control children. The children were divided into four groups (AE: asthma exacerbation, n=12; SA: stable asthma, n=11; IC: infected control, n=6; and NC: non‐infected control, n=5). Total RNA was extracted from peripheral blood mononuclear cells and subjected to microarray analysis with Illumina Human Ref8 BeadChip arrays. Welch's t‐test was performed to identify genes whose expression was altered during asthma exacerbation. Quantitative real‐time RT‐PCR was performed on samples collected from 43 asthmatic children and 11 control children to verify the microarray results. Results The expression of 137/16 genes was significantly up/down‐regulated during asthma exacerbation assessed by microarray analysis. Of the genes, 62 were also differentially expressed during upper respiratory infection. Many of the asthma exacerbation related genes were involved in defence responses and responses to external stimuli, but these associations disappeared after excluding the infection‐related genes. Quantitative real‐time RT‐PCR confirmed that the genes related (S100A8 and GAS6) and unrelated to infections (CD200 and RBP7) were differentially expressed during asthma exacerbation (P<0.01). Conclusions Previously unidentified immune responses during asthma exacerbation may provide further clarification of the molecular mechanisms underlying asthma.