All-Order Amplitudes at any Multiplicity in the Multi-Regge Limit

We propose an all-loop expression for scattering amplitudes in planar N=4 super Yang-Mills theory in multi-Regge kinematics valid for all multiplicities, all helicity configurations, and arbitrary logarithmic accuracy. Our expression is arrived at from comparing explicit perturbative results with general expectations from the integrable structure of a closely related collinear limit. A crucial ingredient of the analysis is an all-order extension for the central emission vertex that we recently computed at next-to-leading logarithmic accuracy. As an application, we use our all-order formula to prove that all amplitudes in this theory in multi-Regge kinematics are single-valued multiple polylogarithms of uniform transcendental weight.

Morphology and connections of the abdominal accessory neurons of the crayfish Cherax destructor

Associated with the abdominal muscle receptor organs of crayfish are accessory neurons that inhibit the activity of the stretch receptors. Cobalt infusion into their cut axons reveals four accessory somata associated with each hemiganglion in the abdomen of the crayfish Cherax destructor. These conform to the pattern described previously for these neurons: The cell bodies are in the ganglion posterior to the one from which they exit. We recorded intracellularly from the largest accessory neurons, Acc-1 and Acc-2, and stained them with intracellular dye to establish unambiguously the characteristics defining their identity and structure. We describe their branching patterns in the ganglion of origin and the ganglion of exit. This morphological information permitted us to distinguish all four accessory neurons in preparations with dye infused through their cut axons, and we propose a revised, unambiguous nomenclature for the two smaller ones. Our intracelluar recordings allowed us to reexamine the physiological relationships of Acc-1 and Acc-2, the only accessory neurons for which there are data in the literature. In general, the connections and inputs described in previous studies were substantiated, although there has clearly been confusion between the two, and they differ in a number of significant ways. We found that they are seldom active together, have different firing patterns, and may operate with different clusters of extensor and flexor motorneurons. The results illustrate the level at which the accessory neurons operate within the abdominal control system but do not distinguish between competing hypotheses concerning their role in behavior. The data are consistent with the view that accessory neurons assist in timing between adjacent segments.

The cord stretch receptors in the abdominal nerve cord of the crayfish Cherax destructor: physiology and relationships

The physiology and relationships of tonic cord stretch receptor neurons in the crayfish Cherax destructor were examined with intracellular and extracellular recording. Cord stretch evoked slow depolarisations leading to action potentials in tonic cord stretch receptor neurons. Intermittent post-synaptic potentials were also seen in cord stretch receptor neurons but were not the primary cause of the action potentials. Cord stretch still evoked action potentials in cord stretch receptor neurons when all synaptic activity, monitored at another known chemical synapse, was blocked using high [Mg(2+)] and low [Ca(2+)] in the bath. One source of facilitating excitatory post-synaptic potentials in the cord stretch receptor neurons was from mechanosensory hairs on the dorsal abdominal surface. Tonic cord stretch receptor neuron activity was associated with an increase in the activity of the abdominal slow extensor inhibitor motor neuron and at least one abdominal flexor excitor motor neuron in its segment, and reduced activity in the abdominal slow flexor inhibitor motor neuron. Activation of individual cord stretch receptor neurons produced a local resistance reflex. Cord stretch, activating many receptors, produced several other outcomes. One was the "extensor state" described in earlier literature. The tonic cord stretch receptor neurons of Cherax destructor appear to be stretch-sensitive interneurons that receive inputs from other elements of the abdominal control system and mediate polysynaptic reflex activity in postural motor neurons.

Extracorporeal shock-wave lithotripsy. Initial Australian experience

Fifty patients were treated with extracorporeal shock-wave lithotripsy for upper urinary tract calculi. The procedure was performed by means of either epidural or general anaesthesia. There were minimal postoperative complications with a mean length of stay of 3.6 days. Six patients required a repeat extracorporeal shock-wave lithotripsy procedure for residual fragments during their initial admission to hospital. Forty (80%) patients were free of all stone fragments within one month of their discharge from hospital. Three patients have residual fragments of greater than 2 mm in axial length. The remainder underwent other procedures to remove residual stones or will be treated with further extracorporeal shock-wave lithotripsy therapy.

A controlled clinical trial of machine perfusion of cadaveric donor renal allografts

Outcome in eighty-eight recipients of cadaveric donor renal allografts preserved before implantation by machine perfusion with a solution of human albumin was compared to that for eighty-three recipients of similar kidneys implanted after simple cold storage. Average total ischaemic intervals for machine-perfused and cold-stored kidneys were 18 and 4 1/4 hours, respectively. Machine-perfused kidneys were implanted regardless of perfusion characteristics. Initial function and 1-month and 1-year graft survivals for the machine-perfused group (58%, 85%, 68%, respectively) were either similar or improved compared to those of cold-stored kidneys (58%, 81%, 52%, respectively). Improved 1-year survival for machine-perfused grafts was dependent upon reduced rejection. Careful donor selection and management ensured good machine perfusion of kidneys on 90% of occasions. In the other 10%, despite poor perfusion characteristics, outcome for kidneys was similar to those with good perfusion characteristics. Antilymphocyte globulin treatment reduced rejection whether allografts were machine perfused or not. In the absence of antilymphocyte globulin treatment, machine-perfused kidneys did much better than cold-stored kidneys. Machine perfusion had important advantages and improved the results in kidney-graft recipients.