Investigation of the Periodic Magnetic Field Modulation Inside Apertures of LHC Superconducting Dipole Models

The windings of high-field accelerator magnets are usually made of Rutherford-type superconducting cables. The magnetic field distribution along the axis of such magnets exhibits a pronounced periodic modulation with a wavelength equal to the twist pitch length of the cable used in the winding. Such an effect, resulting from quasi-persistent currents, was investigated with a Hall probe array inserted inside the aperture of 1-metre long LHC superconducting dipole models. The amplitude and the time dependence of this periodic field oscillation have been studied as a function of the transport current history. The impact on the magnet stability of the non-uniform current redistribution producing such a field modulation is discussed

Investigation of the Periodic Magnetic Field Modulation in LHC Superconducting Dipoles

The windings of high-field accelerator magnets are usually made of Rutherford-type superconducting cables. The magnetic field distribution along the axis of such magnets exhibits a periodic modulation with a wavelength equal to the twist pitch length of the cable used in the winding. This effect, resulting from quasi-persistent currents, was investigated with a Hall probes array inserted inside the aperture of the LHC superconducting dipoles, both in short models and full-scale prototypes. The amplitude and the time dependence of this periodic field oscillation have been studied as a function of the magnet current history. The origin and the impact on the LHC dipoles stability of the non-uniform current redistribution producing such a field modulation are discussed

Lepton Polarization in Neutrino-Nucleon Interactions

We derive generic formulas for the polarization density matrix of leptons produced in neutrino and antineutrino collisions and briefly consider some important particular cases. Next we employ the general formalism in order to include the final lepton mass and spin into the popular model by Rein and Sehgal for single pion neutrinoproduction.Comment: Talk given at 10th International Workshop on High-Energy Spin Physics (SPIN 03), Dubna, Russia, 16-20 Sep 2003. 12 pages; extended version, typos remove

2OACTIVATION OF T CELLS UPON TREATMENT WITH BISPECIFIC ANTIBODIES CORRELATES WITH THE EXPRESSION OF CO-INHIBITORY RECEPTORS ON TUMOR-INFILTRATING LYMPHOCYTES IN HUMAN LUNG CANCER

Introduction: T cell bispecific antibodies (TCB) are designed to recruit and simultaneously activate T cells against target cells such as tumor cells expressing a particular surface antigen. However, it is currently unknown how immuno-modulatory mechanisms active in the tumor microenvironment such as the expression of T cell co-inhibitory receptors may influence the therapeutic effect of TCBs. Methods: We performed a comprehensive phenotypic analysis of tumor infiltrating immune cells from lung carcinoma digests by multicolour flow cytometry. In particular, expression of T cell co-inhibitory and -stimulatory receptors was analyzed. Tumor digests were treated with catumaxomab, a TCB directed against CD3 and EpCAM. T cell activation and effector functions were assessed upon exposure to catumaxomab. Results: CD8+ T cells in lung carcinoma showed a broad heterogeneity in expression of the T cell co-inhibitory receptors PD-1, Tim-3, CTLA-4, Lag-3 and BTLA. Tumor stage and nodal status correlated with number and intensity of expressed receptors. Upon exposure to catumaxomab, a considerable heterogeneity in T cell activation among different tumors was observed. Of note, T cells expressing high levels and multiple co-inhibitory receptors were more impaired in their activation and effector functions after treatment with catumaxomab indicating a higher level of exhaustion. In a further analysis of CD8+ TIL subsets we found that BTLA+ T cells expressed more additional inhibitory receptors than all other subsets, namely PD-1, Tim-3, CTLA-4 and Lag-3, whereas only a small part of PD-1+ T cells expressed another receptor. Tim-3+ T cells usually co-expressed PD-1, but multiple receptors were found only on a low number of cells. Conclusion: In summary, our data suggest that the activity of TCBs is largely affected by the expression of T cell co-inhibitory receptors on tumor-infiltrating immune cells. Furthermore, these data provide a clinical rationale for combining bispecific antibodies with compounds which antagonize T cell exhaustion. Disclosure: D. Thommen, J. Schreiner, P. Herzig, P. Mueller and A. Zippelius: received research funding from Roche Glycart; V. Karanikas: is employed by Roche Glycart. All other authors have declared no conflicts of interes

Resonance production by neutrinos: I. J=3/2 Resonances

The article contains general formulas for the production of J=3/2 resonances by neutrinos and antineutrinos. It specializes to the P_{33}(1232) resonance whose form factors are determined by theory and experiment and then are compared with experimental results at low and high energies. It is shown that the minimum in the low Q^2 region is a consequence of a combined effect from the vanishing of the vector form factors, the muon mass and Pauli blocking. Several improvements for the future investigations are suggested.Comment: 10 pages, LaTeX, misprints corrected, 1 reference adde

The atmospheric charged kaon/pion ratio using seasonal variation methods

Observed since the 1950's, the seasonal effect on underground muons is a well studied phenomenon. The interaction height of incident cosmic rays changes as the temperature of the atmosphere changes, which affects the production height of mesons (mostly pions and kaons). The decay of these mesons produces muons that can be detected underground. The production of muons is dominated by pion decay, and previous work did not include the effect of kaons. In this work, the methods of Barrett and MACRO are extended to include the effect of kaons. These efforts give rise to a new method to measure the atmospheric K/$\pi$ ratio at energies beyond the reach of current fixed target experiments. These methods were applied to data from the MINOS far detector. A method is developed for making these measurements at other underground detectors, including OPERA, Super-K, IceCube, Baksan and the MINOS near detector.Comment: 15 pages, 4 figures, submitted to Astropart. Phy

Distribuição espacial de Grevillea robusta em plantações de café.

bitstream/item/101430/1/1984-PA76-Baggio-DistribuicaoEspacial.pd

Magnetic and chemical properties of Cr-based films grown on GaAs(001)

We have investigated the magnetic and chemical properties of very thin Cr films, CrAs, and arsenized Cr grown by molecular beam epitaxy on Ga As (001), using x-ray photoemission spectroscopy and SQUID magnetometry. Distintic preparation procedures have been used with the purpose to undestand the origin of the ferromagneti signal observed for this system. It results that Ga segregation and chemical reactivity between Ga and Cr have negligible contribution in the formation of different thi films. A clear ferromagnetic response even at room temperature suggests the existence of a very thin interfacial layer formed that can eventually be burid during the growth process.Comment: 16 pages, 6 figure