Search

The problem of representing scattering data given on the boundary of the analyticity domain by analytic functions satisfying unitarity is investigated. The optimal representation inL2-norm is shown to be the solution of a constrained convex optimization problem in some Hilbert space of analytic functions. A duality optimization theorem based on the generalized Lagrange multiplier technique is applied for solving this problem. The method is found to easily accommodate unequal errors on the real and imaginary parts of the amplitude and the case of data given along a limited part of the boundary.

A method for determining high-energy parameters from low-energy data is described and applied to the π N forward charge-exchange amplitude A ′ (−) . Unlike the usual FESR or CMSR which are based upon the Cauchy integral formula (dispersion relations) the present method used the solution of an extremal problem in the space of analytic functions. This allows us to derive in a completely model independent way optimal bounds on Regge residues and correlations between Regge parameters and low-energy data.

We investigated the celite activation of coagulation in heparinized plasma. Celite is shown, using the thrombelastograph, to produce clotting in plasma samples containing pharmacologic levels of heparin (e.g. 1.45 U/ml). We demonstrate that the celite-induced clotting involves Hageman factor, requires calcium, and is not due to celite absorption of heparin. Incubation at 37°C of celite activated plasma samples prior to recalcification, causes a progressive loss in coagulation potential. Unheparinized samples do not exhibit a similar loss. We found that the minimum concentration of heparin required to prevent celite-activated coagulation also reduces celite-activated esterase activity. Massive contact activation is suggested as the most likely explanation for the observed clotting of heparinized samples. Qualitative effects of cellular elements in the plasma are also reported. Finally, the results suggest that using celite activated samples in the thrombelastograph is an improved method for clinical monitoring of heparin effectiveness.

The possibility to write Veneziano formulae for the amplitudes of the process πω→πA1 is investigated. It is found that the asymptotic behaviours of the invariant amplitudes, the positions of the lowest poles, the elimination of parity doubling on the leading trajectories, the factorization properties of the Regge residues and the Adler condition can be consistently imposed and considerably reduce the number of arbitrary parameters. Using a current algebra technique in the soft-pion limit, a Veneziano-like expression for the pseudoscalar-vector-vector vertex is deduced. The result is consistent with the hypothesis of the meson dominance of the vectorial current.

a digital filter for improving the resolution of spectra composed of overlapping lines is presented, an emphasis being laid on the possibilities of diminishing both the oscillations of the response and the inherent decrease of the signal to noise ratio.

The digital filtering was proven to be useful in processing convolved signals. In this paper an application of this method in order to improve the resolution of nuclear and magnetic resonance spectra is presented, An emphasis is laid on the possibility of diminishing the noisy secondary effects. The processing was achieved using the FFT algorithm. Some practical results obtained are delivered.

The dynamics of clot formation using either thrombin or arvin to clot purified human fibrinogen F XIII free fibrinogen and human plasma was studied using the thrombelastograph (TEG). Varying concentrations of these components including calcium were observed for their effects on the overall clotting patterns. The action of plasmin or urokinase on these systems was also evaluated. The production of equal area thrombelastographic tracings required over four times the amount of Ancrod compared to thrombin in the absence of calcium. Calcium ions exerted profound effects upon the TEG configuration inhibiting clot formation at certain concentrations in the Ancrod system, while enhancing the rate and size of fibrin formation in the thrombin systems. These changes were heavily influenced by the ionic strength of the buffer system, and appear related to factor XIII activation. No TEG differences were observed when thrombin or Ancrod formed clots were subjected to proteolysis in the absence of calcium. Enhancement of Ancrod but not thrombin clots subjected to proteolysis in the presence of calcium was observed with early Ancrod samples, but this phenomenon was minimal with more purified Ancrod solutions available recently. Doubling of the control area was demonstrated in some cases with the less pure Ancrod and appeared to be related to the dose of urokinase employed. If one assumes that the lytic agents preferentially attack the residual fibrinogen molecule rather than formed fibrin then greater amounts of fibrin monomer could result and produce a larger initial clot than with Ancrod alone. Repeating these experiments with F XIII free fibrinogen produced the same results. Enhancement effects disappeared when the proteolytic agent was added after clotting had begun, and increased lytic susceptibility of the impure Ancrod systems sometimes occurred under these circumstances. Ancrod and thrombin formed fibrin clots exhibit different characteristics depending upon the nature of the test system. The potential thrombogenic properties of the earlier contaminated Ancrod samples emphasized the importance of using only the pure preparations for therapy in man.

Fifty-seven patients suffering from acute bleeding were studied with multiple (25) different coagulation tests. Twenty-three of the 57 patients underwent operation, including six in whom operative intervention was delayed in order to improve coexistent hematologic abnormalities. Bleeding in five of these six "delayed" subjects and, overall, in 20 of these 23 patients was successfully controlled by operation. The remaining 34 patients, so-called "medical bleeders," included eight originally considered for operation, but in whom this was avoided as a result of the coagulation profile. Medical treatment successfully arrested the bleeding in six of these eight patients. The study demonstrates the value of adequate preoperative coagulation testing in recognizing and correcting obvious hematologic abnormalities, minimizing unnecessary operations, and reducing the possibility of catastrophic intraoperative hemorrhage.