Extremum-entropy-based Heisenberg-like uncertainty relations

In this work we use the extremization method of various information-theoretic measures (Fisher information, Shannon entropy, Tsallis entropy) for $d$-dimensional quantum systems, which complementary describe the spreading of the quantum states of natural systems. Under some given constraints, usually one or two radial expectation values, this variational method allows us to determine an extremum-entropy distribution, which is the \textit{least-biased} one to characterize the state among all those compatible with the known data. Then we use it, together with the spin-dependent uncertainty-like relations of Daubechies-Thakkar type, as a tool to obtain relationships between the position and momentum radial expectation values of the type $\langle r^{\alpha}\rangle^{\frac{k}{\alpha}}\langle p^k\rangle\geq f(k,\alpha,q,N), q=2s+1$, for $d$-dimensional systems of $N$ fermions with spin $s$. The resulting uncertainty-like products, which take into account both spatial and spin degrees of freedom of the fermionic constituents of the system, are shown to often improve the best corresponding relationships existing in the literature.Comment: Accepted for publication in Journal of Physics

Modeling Compressible Non-Newtonian Chicken Flow

This paper addresses a few modeling issues relevant for the basic theoretical understanding of the meat flow behavior in simple geometries. We model the meat mixture as a non-Newtonian compressible fluid. Focusing on conceptually easy-to-follow cases like flow in thin molds, or steady incompressible or compressible flow in straight pipes we derive explicit expressions for the velocity and pressure profiles. For the thin moldcase, we formulate a one-dimensional free-boundary problem able to capture the a priori unknown position of the moving meat-air interface. Special attention is payed on the derivation of the free boundary conditions

Indications for pediatric liver transplantation

Two hundred fifty pediatric (<18 years of age) patients underwent orthotopic liver transplantation because of end-stage liver disease and were given combination therapy with cyclosporine and prednisone. The most common indications for transplantation in decreasing order of frequency were biliary atresia, inborn errors of metabolism, and postnecrotic cirrhosis. The 5-year actuarial survival for the entire group was 69.2%. Age and diagnosis did not influence survival. Infections were the most common cause of death, followed by liver failure and cerebrovascular accident. The impact of retransplantation on survival depends on the indication. The survival is better when retransplantation is carried out after rejection than because of technical complications, and the latter has a better survival than does primary graft nonfunction. The difference in survival among these groups is statistically significant. The quality of life for 164 of 173 survivors is good to excellent; only nine children are currently experiencing medical problems. A persistent problem in pediatric transplantation is the scarcity of small donors. © 1987 The C. V. Mosby Company

Jeans instability of a galactic disk embedded in a live dark halo

We investigate the Jeans instability of a galactic disk embedded in a dynamically responsive dark halo. It is shown that the disk-halo system becomes nominally Jeans unstable. On small scales the instability is suppressed, if the Toomre stability index Q_T is higher than a certain threshold, but on large scales the Jeans instability sets invariably in. However, using a simple self-consistent disk-halo model it is demonstrated that this occurs on scales which are much larger than the system so that this is indeed only a nominal effect. From a practical point of view the Jeans instability of galactic disks is not affected by a live dark halo.Comment: 3 pages, 1 figure, accepted by Astron. Astrophy

Dynamical friction force exerted on spherical bodies

We present a rigorous calculation of the dynamical friction force exerted on a spherical massive perturber moving through an infinite homogenous system of field stars. By calculating the shape and mass of the polarization cloud induced by the perturber in the background system, which decelerates the motion of the perturber, we recover Chandrasekhar's drag force law with a modified Coulomb logarithm. As concrete examples we calculate the drag force exerted on a Plummer sphere or a sphere with the density distribution of a Hernquist profile. It is shown that the shape of the perturber affects only the exact form of the Coulomb logarithm. The latter converges on small scales, because encounters of the test and field stars with impact parameters less than the size of the massive perturber become inefficient. We confirm this way earlier results based on the impulse approximation of small angle scatterings.Comment: 5 pages, 2 figures, accepted in MNRA

Shear Force at Failure and Stiffness of All-Inside Meniscal Repair Devices

The purpose of this study was to determine the failure load and stiffness of various meniscal repair devices. A total of 61 fresh-frozen porcine menisci (medial and lateral) were used for the study. A 30-mm vertical, full-thickness tear was created and repaired using one of three all-inside fixation devices and one inside–out repair in the vertical mattress pattern. We used the MaxBraid (Biomet, Warsaw, IN) inside–out suture as a control. The other devices tested were the Meniscal Cinch (Arthrex, Naples, FL), Ultra FasT-Fix (Smith & Nephew, Andover, MA), and the MaxFire MarXmen (Biomet, Warsaw, IN). In addition, two devices, MaxFire MarXmen and Ultra FasT-Fix, were tested using a horizontal mattress configuration. Using the vertical mattress pattern, the Meniscal Cinch had the highest average load to failure. The Meniscal Cinch was significantly less stiff than the other three devices (p \u3c 0.04). For the MarXmen and Ultra FasT-Fix, no differences were noted for load to failure between horizontal and vertical mattress patterns. The mode of failure was significantly different when comparing the two different surgical techniques for the MaxFire MarXmen (p = 0.005). The MaxFire MarXmen device produced a significantly stiffer (p  \u3c 0.001) construct when following the manufacturer\u27s instructions (5.8 N/mm) than with the technique used for the other all-inside devices (2.5 N/mm) The Meniscal Cinch had the highest load-to-failure value but the lowest stiffness of the group in the vertical mattress configuration. There was little difference in biomechanical properties between vertical and horizontal repair. Importantly, there was a significant difference in stiffness and failure mode for the MaxFire MarXmen when the manufacturer guidelines were not specifically followed

Liver transplantation before 1 year of age

Since 1981, 20 infants younger than 1 year of age received 26 orthotopic liver transplants. Immunosuppression was with cyclosporine and corticosteroids. Thirteen (65%) of the reciplents were discharged from the hospital. To date, 12 (60%) of the 20 reciplents are surviving, with follow-up of 1 to 56 months (average 14 months). The 5-year acluarial survival is 53.8%. The allograft liver function in the majority of surviving infants is excellent. The predominant causes of mortality were primary nonfunction of the allograft (three patients) and sepsis (three). Major morbidity was caused by hepatic artery thrombosis (five patients), gastrointestinal complications (six), biliary tract complications (five), and bacterial and viral infections (13). Six patients underwent retransplantation; three of these six survived. Results could be improved by prevention of hepatic artery thrombosis, by decreasing the incidence of sepsis, and by procurement of more and better suited pediatric donors. © 1987 The C. V. Mosby Company