The space of transport coefficients allowed by causality.

As an effective theory, relativistic hydrodynamics is fixed by symmetries up to a set of transport coefficients. A lot of effort has been devoted to explicit calculations of these coefficients. Here we adopt a more general approach, deploying bootstrap techniques to rule out theories that are inconsistent with microscopic causality.

Rigorous Bounds on Transport from Causality.

We use causality to derive a number of simple and universal constraints on dispersion relations, which describe the location of singularities of retarded two-point functions in relativistic quantum field theories. We prove that all causal dissipative dispersion relations have a finite radius of convergence in cases where stochastic fluctuations are negligible. We then give two-sided bounds on all transport coefficients in units of this radius, including an upper bound on diffusivity.

Hydrodynamic Gradient Expansion Diverges beyond Bjorken Flow.

The gradient expansion is the fundamental organizing principle underlying relativistic hydrodynamics, yet understanding its convergence properties for general nonlinear flows has posed a major challenge. We introduce a simple method to address this question in a class of fluids modeled by Israel-Stewart-type relaxation equations. We apply it to (1+1)-dimensional flows and provide numerical evidence for factorially divergent gradient expansions.

Lead toxicity in captive and wild Mallards (Anas platyrhynchos) in Spain.

Forty captive Mallards (Anas platyrhynchos), of both sexes, were separated into five groups and dosed with lead shot via oral intubation; one group was used as a control. Lead dosage differed in terms of shot number and size, as well as administration time. One hundred and thirty-five wild mallards were trapped between 1998 and 2001 in the Boada and Nava lagoons near the Canal de Castilla, in the Spanish province of Palencia.

Imaging diagnosis--Medullary tibial infarction in a horse.

An Andalusian Stallion with left hind limb lameness had a radiolucent lesion in the medullary cavity of distal tibial metaphysis. After euthanasia for other disease, the tibia was examined with magnetic resonance (MR). The MR imaging sequences were characterized by a double line sign, although showing quite different lesion area intensities.

Dehiscence of gastrojejunal stapled anastomosis after lithotripsy for nephrolithiasis.

We report the case of a 76-year-old woman with previous bariatric surgery and a large renal calculus following a prolonged lithotripsy session. The patient presented with peritonitis due to dehiscence of the gastrojejunal stapled anastomosis.

Lipoma-induced jejunojejunal intussusception: US and CT diagnosis.

A case study of a patient who presented with abdominal pain and a palpable mesogastric mass is discussed. Ultrasound and computed tomography (CT) demonstrated that the palpable mass was jejunojejunal intussusception of the small intestine. The lead point of the intussusception was a lipoma that appeared in the CT scan as a small intramural mass with an attenuation coefficient of fat.

Microsurgery in gaining paediatric vascular access for haemodialysis.

One hundred and one surgical procedures performed in children for construction and maintenance of vascular accesses for haemodialysis were retrospectively analyzed. There were 86 operations performed to create a new fistula in patients without vascular access or with nonrecoverable failed angio-access. Fifteen surgical procedures were performed to treat fistula complications.

[A biliary fistula after T-tube removal in the transplant patient: its diagnosis by Tc-99m-HIDA].

The Tc-99m HIDA scan is a valuable study after liver transplantation, associated with other image techniques. We have used this technique as a reliable and objective diagnostic method for biliary fistula after removal of the T-tube in 5 liver transplantation patients with pain after T-tube removal. All five patients who developed fistula not only were diagnosed immediately but, furthermore, the surgical technique was indicated by the gammagraphic study.