Dynamic Properties of Charmonium

Nonrelativistic quark models of charmonia are tested by comparison of theoretical charmonium decay constants, form factors, and $\gamma\gamma$ widths with experiment and lattice gauge computations. The importance of relativistic effects, a running coupling, and the correct implementation of bound state effects are demonstrated. We describe how an improved model and computational techniques resolve several outstanding issues in previous nonrelativistic quark models such as the use of `correction' factors in quark model form factors, artificial energy prescriptions in decay constant calculations, and ad hoc phase space modifications. We comment on the small experimental value of $f_{\psi''}$ and the D-wave component of the $J/\psi$. Decay constants and $\gamma\gamma$ widths for bottomonium are also presented.Comment: 22 pages, 22 ps figures (table entries corrected, text modified

Flow competition between hepatic arterial and portal venous flow during hypothermic machine perfusion preservation of porcine livers

Hypothermic machine perfusion (HMP) is regarded as a better preservation method for donor livers than cold storage. During HMP, livers are perfused through the inlet blood vessels, namely the hepatic artery (HA) and the portal vein (PO. In previous HMP feasibility studies of porcine and human livers, we observed that the PV flow decreased while the HA flow increased. This flow competition restored either spontaneously or by lowering the HA pressure (P-HA). Since this phenomenon had never been observed before and because it affects the HMP stability, it is essential to gain more insight into the determinants of flow competition. To this end, we investigated the influence of the HMP boundary conditions on liver flows during controlled experiments. This paper presents the flow effects induced by increasing P-HA and by obstructing the outlet blood vessel, which is the vena cava inferior (VCI). Flow competition was evoked by increasing P-HA to 55-70 mmHg, as well as by obstructing the VCI. Remarkably, a severe obstruction resulted in a repetitive and alternating tradeoff between the HA and PV flows. These phenomena could be related to intra-sinusoidal pressure alterations. Consequently, a higher P-HA is most likely transmitted to the sinusoidal level. This increased sinusoidal pressure reduces the pressure drop between the PV and the sinusoids, leading to a decreased PV perfusion. Flow competition has not been encountered or evoked under physiological conditions and should be taken into account for the design of liver HMP protocols. Nevertheless, more research is necessary to determine the optimal parameters for stable HMP

A chromomagnetic mechanism for the X(3872) resonance

The chromomagnetic interaction, with proper account for flavour-symmetry breaking, is shown to explain the mass and coupling properties of the X(3872) resonance as a $J^{PC}$ = 1$^{++}$ state consisting of a heavy quark-antiquark pair and a light one. It is crucial to introduce all the spin-colour configurations compatible with these quantum numbers and diagonalise the chromomagnetic interaction in this basis. This approach thus differs from the molecular picture $D\bar {D}*$ and from the diquark-antidiquark picture.Comment: 4 pages - revtex4 - Typos corrected, refs. added, to be published in Phys. Rev.

Comprehensive data management for an ocean observatory: ONC\u27s Oceans 2.0

Ocean Networks Canada operates several comprehensive cabled ocean networks and a suite of single-point marine observing systems across Canada. Data flow in real-time from hundreds of sensors, installed beneath the ocean bottom, though the water column, and at the ocean surface. ONC has built a complimentary data management system, Oceans 2.0 that allows for real-time acquisition, secure storage, data exploration, and data product delivery. Key elements of the Oceans 2.0 data management system will be high-lighted, with a focus on best practices and lessons learned

Proposal to improve the behaviour of self-energy contributions to the S-matrix

A simple modification of the definition of the S-matrix is proposed. It is expected that the divergences related to nonzero self-energies are considerably milder with the modified definition than with the usual one. This conjecture is verified in a few examples using perturbation theory. The proposed formula is written in terms of the total Hamiltonian operator and a free Hamiltonian operator and is therefore applicable in any case when these Hamiltonian operators are known.Comment: 24 pages, 1 figure; v2: revised version; v3: section 3 improved. Accepted for publication in Central European Journal of Physics; v4: minor text misprints correcte

World's longest surviving liver-pancreas recipient

In July 1988, the liver and pancreas of a cadaveric donor were transplanted separately into a man with type 1 diabetes with end-stage chronic hepatitis B virus. Two features of the operation may help explain the patient's current status as the longest-lived liver-pancreas recipient. One was enteric drainage of pancreatic exocrine secretions. The other was delivery of the pancreas venous effluent to the host portal system and then directly to the hepatic allograft. © 2007 AASLD