Distortions of parton distributions due to multiquark effects

It has been observed that the momentum distributions of partons in bound nuclei are distorted relative to those of free protons and neutrons. This phenomenon was first observed in deep inelastic scattering experiments with muon and neutrino beams on nuclear targets and is known as the EMC effect. Similar phenomena have been observed in other high energy interactions such as the Drell-Yan process, the hadroproduction of direct photons, and the resonance production of charmonium and bottomonium states. In this work we investigate the possibility that these effects are predominantly of partonic origin. Standard nuclear quantum mechanics predicts that there is a non-zero probability for bound nucleons to overlap forming complex color singlets. We examine whether the observed EMC-type effects can be attributed to the difference between the parton momentum distributions in such clusters and those in single nucleons. We present a systematic way of determining these distributions in the Bjorken scaling limit and of estimating the average number of multiquark clusters in nuclei. The model predicts depletion of the valence quark and enhancement of the ocean quark and gluon components as the cluster baryon number increases. These properties can naturally explain significant features of the high energy behavior of nuclear targets

Resolution of a periodontoid rheumatoid pannus mass in an elderly patient treated with a rigid cervical collar: A case report and literature review

In patients with C2 rheumatoid pannus with spinal cord compression the treatment of choice is extensive surgery either through a transoral resection of the dens axis or a dorsal stabilisation, or both. We present a case of an 11-mm rheumatoid pannus with significant compression of the spinal cord, which failed surgical treatment with respect to dorsal stabilisation. Therefore, rigid cervical collar for 8 weeks followed by soft collar for another 4 weeks was chosen as a treatment option. During the follow-up period of 1 year, the pannus reduced significantly and the spinal cord decompressed. In cases where surgery is not an option or is technically very demanding, the alternative of cervical collar immobilisation is a satisfying option

Prevalence of Antibodies Against Virus-Like Particles of Epidermodysplasia Verruciformis-Associated HPV8 in Patients at Risk of Skin Cancer

There is increasing evidence for widespread occurrences of infection with Epidermodysplasia verruciformis-related human papillomaviruses, both in the general population and in immunosuppressed patients. In order to test for the prevalence of antibodies directed against the native L1 epitopes exposed on the surface of the virions, we have established an IgG-specific enzyme-linked immunosorbent assay with L1 virus-like particles of the Epidermodysplasia verruciformis-specific human papillomavirus 8 as antigen to screen 567 representative serum samples from the general population and immunosuppressed/dermatologic patients. Among healthy European donors (n = 210), 7.6% were found to be seropositive. In a group of renal transplant recipients (n = 185) the antibody prevalence was elevated to 21.1%, irrespective of the presence or absence of skin cancer. High positivity rates could be detected among (i) immunocompetent patients with nonmelanoma skin tumors (45.6%, n = 79) and (ii) Psoralene/UVA treated psoriasis patients (42.9%, n = 42). In contrast, anti-human papillomavirus 8-virus-like particle antibodies were found in only 6.8% of Hodgkin lymphoma patients (n = 44)

Centrality dependence of pi(+/-), K-+/-, p, and (p)over-bar production from root(NN)-N-S = 130 GeV Au+Au collisions at RHIC

Identified pi(+/-), K+/-, p, and (p) over bar transverse momentum spectra at midrapidity in root s(NN) = 130 GeV Au + Au collisions were measured by the PHENIX experiment at RHIC as a function of collision centrality. Average transverse momenta increase with the number of participating nucleons in a similar way for all particle species. Within errors, all midrapidity particle yields per participant are found to be increasing with the number of participating nucleons. There is an indication that K+/-, p, and (p) over bar yields per participant increase faster than the pi(+/-) yields. In central collisions at high transverse momenta (p(T) greater than or similar to 2 GeV/c), (p) over bar and p yields are comparable to the pi(+/-) yields

Net charge fluctuations in Au+Au interactions root s(NN)=130 GeV

Data from Au+Au interactions at s(NN)=130 GeV, obtained with the PHENIX detector at the Relativistic Heavy-Ion Collider, are used to investigate local net charge fluctuations among particles produced near midrapidity. According to recent suggestions, such fluctuations may carry information from the quark-gluon plasma. This analysis shows that the fluctuations are dominated by a stochastic distribution of particles, but are also sensitive to other effects, like global charge conservation and resonance decays

Suppression of hadrons with large transverse momentum in central Au+Au collisions at root s(NN)=130 GeV

Transverse momentum spectra for charged hadrons and for neutral pions in the range 1 Gev/c \u3c P - T \u3c 5 GeV/c have been measured by the PHENIX experiment at RHIC in Au + Au collisions at root S(NN) = 130 GeV. At high p(T) the spectra from peripheral nuclear collisions are consistent with scaling the spectra from p + p collisions by the average number of binary nucleon-nucleon collisions. The spectra from central collisions are significantly suppressed when compared to the binary-scaled p + p expectation, and also when compared to similarly binary-scaled peripheral collisions, indicating a novel nuclear-medium effect in central nuclear collisions at RHIC energies

Event-by-event fluctuations in mean p(T) and mean e(T) in root s(NN)=130 GeV Au+Au collisions

Distributions of event-by-event fluctuations of the mean transverse momentum and mean transverse energy near mid-rapidity have been measured in Au+Au collisions at roots(NN)=130 GeV at the Relativistic Heavy-Ion Collider. By comparing the distributions to what is expected for statistically independent particle emission, the magnitude of nonstatistical fluctuations in mean transverse momentum is determined to be consistent with zero. Also, no significant nonrandom fluctuations in mean transverse energy are observed. By constructing a fluctuation model with two event classes that preserve the mean and variance of the semi-inclusive p(T) or e(T) spectra, we exclude a region of fluctuations in root s(NN)=130 GeV Au+Au collisions