Roles of Fast-Cyclotron and Alfven-Cyclotron Waves for the Multi-Ion Solar Wind

Using linear Vlasov theory of plasma waves and quasi-linear theory of resonant wave-particle interaction, the dispersion relations and the electromagnetic field fluctuations of fast and Alfven waves are studied for a low-beta multi-ion plasma in the inner corona. Their probable roles in heating and accelerating the solar wind via Landau and cyclotron resonances are quantified. We assume that (1) low-frequency Alfven and fast waves have the same spectral shape and the same amplitude of power spectral density; (2) these waves eventually reach ion cyclotron frequencies due to a turbulence cascade; (3) kinetic wave-particle interaction powers the solar wind. The existence of alpha particles in a dominant proton/electron plasma can trigger linear mode conversion between oblique fast-whistler and hybrid alpha-proton cyclotron waves. The fast-cyclotron waves undergo both alpha and proton cyclotron resonances. The alpha cyclotron resonance in fast-cyclotron waves is much stronger than that in Alfven-cyclotron waves. For alpha cyclotron resonance, an oblique fast-cyclotron wave has a larger left-handed electric field fluctuation, a smaller wave number, a larger local wave amplitude, and a greater energization capability than a corresponding Alfven-cyclotron wave at the same wave propagation angle \theta, particularly at $80^\circ$ < \theta < $90^\circ$. When Alfven-cyclotron or fast-cyclotron waves are present, alpha particles are the chief energy recipient. The transition of preferential energization from alpha particles to protons may be self-modulated by differential speed and temperature anisotropy of alpha particles via the self-consistently evolving wave-particle interaction. Therefore, fast-cyclotron waves as a result of linear mode coupling is a potentially important mechanism for preferential energization of minor ions in the main acceleration region of the solar wind.Comment: 29 pages, 10 figures, 3 tables. Accepted for publication in Solar Physic

System size dependence of associated yields in hadron-triggered jets

We present results on the system size dependence of high transverse momentum di-hadron correlations at $\sqrt{s_{NN}}$ = 200 GeV as measured by STAR at RHIC. Measurements in d+Au, Cu+Cu and Au+Au collisions reveal similar jet-like correlation yields at small angular separation ($\Delta\phi\sim0$, $\Delta\eta\sim0$) for all systems and centralities. Previous measurements have shown that the away-side yield is suppressed in heavy-ion collisions. We present measurements of the away-side suppression as a function of transverse momentum and centrality in Cu+Cu and Au+Au collisions. The suppression is found to be similar in Cu+Cu and Au+Au collisions at a similar number of participants. The results are compared to theoretical calculations based on the parton quenching model and the modified fragmentation model. The observed differences between data and theory indicate that the correlated yields presented here will provide important constraints on medium density profile and energy loss model parameters.Comment: 12 pages, 5 figure

Energy dependence of charged pion, proton and anti-proton transverse momentum spectra for Au+Au collisions at \sqrt{s_NN} = 62.4 and 200 GeV

We study the energy dependence of the transverse momentum (pT) spectra for charged pions, protons and anti-protons for Au+Au collisions at \sqrt{s_NN} = 62.4 and 200 GeV. Data are presented at mid-rapidity (|y| < 0.5) for 0.2 < pT < 12 GeV/c. In the intermediate pT region (2 < pT < 6 GeV/c), the nuclear modification factor is higher at 62.4 GeV than at 200 GeV, while at higher pT (pT >7 GeV/c) the modification is similar for both energies. The p/pi+ and pbar/pi- ratios for central collisions at \sqrt{s_NN} = 62.4 GeV peak at pT ~ 2 GeV/c. In the pT range where recombination is expected to dominate, the p/pi+ ratios at 62.4 GeV are larger than at 200 GeV, while the pbar/pi- ratios are smaller. For pT > 2 GeV/c, the pbar/pi- ratios at the two beam energies are independent of pT and centrality indicating that the dependence of the pbar/pi- ratio on pT does not change between 62.4 and 200 GeV. These findings challenge various models incorporating jet quenching and/or constituent quark coalescence.Comment: 19 pages and 6 figure

Major differences in the dynamics of primary and secondary progressive multiple sclerosis

In patients with primary and secondary progressive multiple sclerosis (MS), major differences in the pattern and extent of abnormality on cerebral magnetic resonance imaging (MRI) between the two groups have recently been demonstrated. In the present study, 24 patients, matched for age, sex, duration of disease, and disability, had serial gadolinium diethylenetriaminepentaacetic acid–enhanced MRI over a 6-month period. The 12 patients in the secondary progressive group had a total of 109 new lesions over this time (18.2 lesions per patient per year) and 87% of these enhanced. Enhancement also occurred within and at the edge of preexisting lesions. In contrast, only 20 new lesions were seen in the primary progressive group (3.3 lesions per patient per year) and only one of these enhanced. There was no difference in the degree of clinical deterioration between the two groups over the 6-month period. These findings may indicate a difference in the dynamics of disease activity between the two forms of progressive MS, particularly in relation to the inflammatory component of the lesions, and have important implications for the selection of patients and the monitoring of disease activity in therapeutic trials

Genetic diversity in populations of Uncinula necator: comparison of RFLP- and PCR-based approaches

Clonal isolates of Uncinula necator, the grapevine powdery mildew pathogen, were characterized by mating type, RFLP and PCR analyses. Five random genomic clones, consisting of three multi-copy and two low-copy sequences, were used as probes for hybridization. The oligonucleotides (CAC)5, (GACA)4, the core sequence of the M-13 minisatellite region and the consensus region from a plant intron splice junction (R1), were used as primers in PCR reactions. The DNA probes detected high levels of genetic diversity in U. necator, identifying 34 unique haplotypes among the 81 isolates analysed, with a Shannon diversity index of D' = 0.85. In comparison, 15 haplotypes were resolved in PCR reactions with the four primers, resulting in a diversity index of D' = 0.59. The overall diversity within the collection, by combining RFLP and PCR data, was D' = 0.88, distinguishing 37 haplotypes. The RFLP analysis provided greater discrimination of individual haplotypes than did PCR. Phenetic analysis of the RFLP and PCR data separately and in combination revealed two broad phenetic groups. The average overall similarity between the two groups was 40%. Mating of isolates from the two phenetic groups resulted in viable ascospores. The combination of RFLP, PCR and mating techniques was effective in determining levels of diversity and provided insight into the genetic relatedness of U. necator isolates

Information sources used by older adults for decision making about tourism and travel destinations

Over the past decade, the older market has emerged as an extremely important one because of its increased purchasing power for most consumer goods and services. The tourism and leisure industry is also targeting people aged 65 years and older, because many possess a relatively large share of discretionary money that they want to spend on travel. This has resulted in increasing attention by the mass media and the advertising industry in particular. This paper discusses the main types of information sources that are used by older adults when they make decisions about tourist and travel destinations, and particularly focuses on the importance of word-of-mouth sources and personal experiences. It also explores the influence of the mass media on trip decision making of older adults, and discusses the importance of brochures, magazines and television as information sources for older adults. Finally, it critiques the lack of senior models in advertising campaigns for travel products that are aimed at the older market