The asymmetry of antimatter in the proton.

The fundamental building blocks of the proton-quarks and gluons-have been known for decades. However, we still have an incomplete theoretical and experimental understanding of how these particles and their dynamics give rise to the quantum bound state of the proton and its physical properties, such as its spin1. The two up quarks and the single down quark that comprise the proton in the simplest picture account only for a few per cent of the proton mass, the bulk of which is in the form of quark kinetic and potential energy and gluon energy from the strong force2. An essential feature of this force, as described by quantum chromodynamics, is its ability to create matter-antimatter quark pairs inside the proton that exist only for a very short time. Their fleeting existence makes the antimatter quarks within protons difficult to study, but their existence is discernible in reactions in which a matter-antimatter quark pair annihilates. In this picture of quark-antiquark creation by the strong force, the probability distributions as a function of momentum for the presence of up and down antimatter quarks should be nearly identical, given that their masses are very similar and small compared to the mass of the proton3. Here we provide evidence from muon pair production measurements that these distributions are considerably different, with more abundant down antimatter quarks than up antimatter quarks over a wide range of momenta. These results are expected to revive interest in several proposed mechanisms for the origin of this antimatter asymmetry in the proton that had been disfavoured by previous results4, and point to future measurements that can distinguish between these mechanisms.

Mechanism of earthquake simulation as a prenatal stressor retarding rat offspring development and chinese medicine correcting the retardation: hormones and gene-expression alteration.

We aimed to investigate the mechanism of shaking as a prenatal stressor impacting the development of the offspring and Chinese medicines correcting the alterations. Pregnant rats were randomized into earthquake simulation group (ESG), herbal group (HG) which received herbal supplements in feed after shaking, and control group (CG). Findings revealed body weight and open field test (OFT) score of ESG offspring were statistically inferior to the CG and HG offspring. The corticosterone levels of ESG were higher than those of CG but not than HG. The dopamine level of ESG was slightly lower than that of the CG and of HG was higher than that of ESG. The 5-HT of ESG was higher than CG and HG. The growth hormone level of the ESG was significantly lower than ESG but not than CG. Gene expression profile showed 81 genes upregulated and 39 genes downregulated in ESG versus CG, and 60 genes upregulated and 28 genes downregulated in ESG versus HG. Eighty-four genes were found differentially expressed in ESG versus CG comparison and were normalized in ESG versus HG. We conclude that maternal shaking negatively affected physical and nervous system development, with specific alterations in neurohormones and gene expression. Chinese herbal medicine reduced these negative outcomes.

Measurement of angular distributions of Drell-Yan dimuons in p+p interactions at 800 GeV/c.

We report a measurement of the angular distributions of Drell-Yan dimuons produced using an 800 GeV/c proton beam on a hydrogen target. The polar and azimuthal angular distribution parameters have been extracted over the kinematic range 4.5

Measurement of Upsilon production for p + p and p + d interactions at 800 GeV/c.

We report a high statistics measurement of Upsilon production with an 800 GeV/c proton beam on hydrogen and deuterium targets. The dominance of the gluon-gluon fusion process for Upsilon production at this energy implies that the cross section ratio, sigma(p+d-->Upsilon)/2sigma(p+p-->Upsilon), is sensitive to the gluon content in the neutron relative to that in the proton. Over the kinematic region 0

Measurement of angular distributions of Drell-Yan dimuons in p+d interactions at 800 GeV/c.

We report a measurement of the angular distributions of Drell-Yan dimuons produced using an 800 GeV/c proton beam on a deuterium target. The muon angular distributions in the dilepton rest frame have been measured over the kinematic range 4.5

Neutron-detected tomography of impurity-seeded superfluid helium.

We describe a neutron radiography technique that can be used to map the distribution of 3He impurities in liquid 4He, providing direct and quantitative access to underlying transport processes. Images reflecting finite normal- and superfluid-component 4He velocity fields are presented.

J/psi polarization in 800-GeV p-Cu interactions.

We present measurements of the polarization of the J/psi produced in 800-GeV proton interactions with a copper target. Polarization of the J/psi is sensitive to the ccmacr; production and hadronization processes. A longitudinal polarization is observed at large x(F), while at small x(F) the state is produced essentially unpolarized or slightly transversely polarized. No significant variation of the polarization is observed versus p(T).

Partonic energy loss and the Drell-Yan process.

We examine the current status of the extraction of the rate of partonic energy loss in nuclei from A-dependent data. The advantages and difficulties of using the Drell-Yan process to measure the energy loss of a parton traversing a cold nuclear medium are discussed. The prospects of using relatively low energy proton beams for a definitive measurement of partonic energy loss are presented.

Energy loss of fast quarks in nuclei.

We report an analysis of the nuclear dependence of the yield of Drell-Yan dimuons from the 800 GeV/c proton bombardment of 2H, C, Ca, Fe, and W targets. Employing a new formulation of the Drell-Yan process in the rest frame of the nucleus, this analysis examines the effect of initial-state energy loss and shadowing on the nuclear-dependence ratios versus the incident proton's momentum fraction and dimuon effective mass. The resulting energy loss per unit path length is -dE/dz = 2.32+/-0.52+/-0.5 GeV/fm. This is the first observation of a nonzero energy loss of partons traveling in a nuclear environment.

Observation of polarization in bottomonium production at square root of s = 38.8 GeV.

We present a measurement of the polarization observed for bottomonium states produced in p-Cu collisions at square root of s = 38.8 GeV. The angular distribution of the decay dimuons of the Upsilon(1S) state shows no polarization at small values of the fractional longitudinal momentum x(F) and transverse momentum p(T) but significant positive transverse production polarization for either p(T)>1.8 GeV/c or for x(F)>0.35. The Upsilon(2S+3S) (unresolved) states show a large transverse production polarization at all values of x(F) and p(T) measured. These observations challenge NRQCD calculations of the polarization expected in the hadronic production of bottomonium states.

Nasopharyngeal carcinoma with dermatomyositis. Analysis of 12 cases.

OBJECTIVES: To evaluate the incidence rate of nasopharyngeal carcinoma with dermatomyositis, the influence of dermatomyositis on clinical course, and complications and survival of patients with nasopharyngeal carcinoma after radiotherapy. DESIGN: A retrospective study of 12 patients with nasopharyngeal carcinoma associated with dermatomyositis, with a maximum follow-up of 228 months. SETTING: Academic tertiary referral center. PATIENTS: There were 6441 new patients with nasopharyngeal carcinoma who were seen at the National Taiwan University Hospital, Taipei, during the period from 1970 through 1993. Twelve patients were found to have dermatomyositis. MAIN OUTCOME MEASURE: Clinical manifestations of nasopharyngeal carcinoma with dermatomyositis. RESULTS: Twenty-seven (26%) of 104 patients with dermatomyositis had an associated malignancy. Twelve of these patients were diagnosed as having nasopharyngeal carcinoma. The typical skin manifestation of dermatomyositis was found in all 12 patients. Myopathy occurred in 10 patients. Three patients died of recurrence of nasopharyngeal carcinoma, one died of a second malignancy, one died of upper gastrointestinal bleeding, and one became unavailable for follow-up. The other six patients have had disease-free survival, with a mean follow-up period of 100.5 months (range, 5 to 228 months). The 1-year survival rate was 83.8%, and the 5-year survival rate was 69.4%. CONCLUSIONS: In Taiwan, dermatomyositis is associated with an increased incidence rate of nasopharyngeal carcinoma. A search for nasopharyngeal carcinoma in patients with dermatomyositis should be performed in areas prevalent for nasopharyngeal carcinoma. If present, nasopharyngeal carcinoma can precede, occur concurrently with, or follow the diagnosis of dermatomyositis. Treatment of nasopharyngeal carcinoma may affect myositic or cutaneous disease. The prognosis and survival rates of nasopharyngeal carcinoma remained unaffected by dermatomyositis. No complications were noted owing to the radiotherapy used to treat dermatomyositis.

[Is reuse of autologous ear ossicles in cholesteatoma or chronic suppurative otitis media justified?]. / Ist die Wiederverwendung autologer Gehörknöchelchen beim Cholesteatom oder der chronischen Schleimhauteiterung gerechtfertigt?

From the 1950s onwards ossicular bone autografts have been used to restore the middle ear sound conduction mechanism. Controversy still exists regarding the appropriateness of autologous ossicular bone grafts in chronic middle ear diseases. This communication is based on a study of 149 ossicles surgically removed from 120 patients with different ear diseases, at the Department of Otolaryngology, Head and Neck Surgery of the University of Wuerzburg. It is the object of this study to systematically investigate the histological findings in the ossicles in cholesteatoma and chronic suppurative otitis media, and also to try to assess their significance. For comparison the ossicles of traumatic subluxation and otosclerosis are also included in our material. In about one-fourth of the incidences of cholesteatoma, squamous epithelium is found adherent to the ossicles with subepithelial connective tissue of varying thickness separating the matrix from the involved ossicle so that the matrix is never in direct contact with the underlying bone. Osteomyelitis is shown in both groups. Bone resorption predominates in the complicated metaplastic process due to the action of osteoclasts irrespective of the cholesteatoma group or the chronic otitis media group. Bone erosion is evident not only on the surface of the ossicles but also in the bone. On the other hand, ossicles in the groups of traumatic subluxation and otosclerosis remain histologically normal without evidence of pathologic changes. On the basis of these histological observations and on account of the high probability of adherent squamous epithelium in our opinion autologous ossicles from cholesteatoma and chronic suppurative otitis media should not be used in reconstructive middle ear surgery.