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Rapid Arctic sea ice retreat has fueled speculation about the possibility of threshold (or ‘tipping point’) behavior and irreversible loss of the sea ice cover. We test sea ice reversibility within a state-of-the-art atmosphere–ocean global climate model by increasing atmospheric carbon dioxide until the Arctic Ocean becomes ice-free throughout the year and subsequently decreasing it until the initial ice cover returns. Evidence for irreversibility in the form of hysteresis outside the envelope of natural variability is explored for the loss of summer and winter ice in both hemispheres. We find no evidence of irreversibility or multiple ice-cover states over the full range of simulated sea ice conditions between the modern climate and that with an annually ice-free Arctic Ocean. Summer sea ice area recovers as hemispheric temperature cools along a trajectory that is indistinguishable from the trajectory of summer sea ice loss, while the recovery of winter ice area appears to be slowed due to the long response times of the ocean near the modern winter ice edge. The results are discussed in the context of previous studies that assess the plausibility of sea ice tipping points by other methods. The findings serve as evidence against the existence of threshold behavior in the summer or winter ice cover in either hemisphere.

PubMed: 16350383 We tested documented in vitro and ex vivo advantages of novel hyaluronan based heparin bonded extracorporeal circuits in a prospective randomized study. During the period from June until September 2005, 40 patients undergoing reoperation for coronary artery bypass grafting were allocated into two equal groups (n = 20): Group 1 was treated with hyaluronan-based heparin-bonded circuits and group 2 was treated with uncoated control circuits. Complete blood count, fibrinogen, albumin, C3a, interleukin-2 levels, and thromboelastographic data were documented after induction of anesthesia (T1) and heparin administration before cardiopulmonary bypass (CPB) (T2), 15 minutes after initiation of CPB (T3), before cessation of CPB (T4), 15 minutes after reversal with protamine (T5), and the first postoperative day at 8:00 a.m. (T6). Hollow fibers were collected for consecutive biomaterial analysis by optical and scanning electron microscopy (SEM). Desorbed protein deposition on fibers was compared by spectrophotometry. Leukocyte counts were lower in T4-T6 in group 1 (p < .05). Platelet counts demonstrated significant differences at T4 and T5 in coated group (p < .05). Albumin and fibrinogen levels were better preserved in Group 1 at T4, T5 and T4, T6, consecutively (p < .05). C3a and IL-2 levels were lower at T3-T5 and T4-T5 in intervention group (p < .05). Postoperative hemorrhage was 412 ± 50 mL in group 1 and 684 ± 50 ml in group 2 (p < .05). Respiratory support time was shorter in group 1 versus control (p < .05). Platelet adhesion was significantly lower in intervention group. Amount of desorbed protein was 1.44 ± 0.01 mg/dL in group 1 and 1.94 ± 0.01 mg/dL in control (p < .05). SEM and spectrophotometry demonstrated better surface preservation in the hyaluronan coated group. Novel hyaluronan-based heparin-bonded circuits reduce platelet adhesion-aggregation and protein adsorption and provide better perioperative clinical parameters through platelet, albumin, and fibrinogen-sparing effects.

PubMed: 16250863 Systemic inflammatory response syndrome (SIRS) with activation of molecular cascades, cell activation, accumulation of interstitial fluid, organ dysfunction and, occasionally, organ failure is still a commonly recognized consequence of cardiac surgery. SIRS leads to costly complications and several strategies intended to ameliorate the symptoms that have been studied, including leukocyte reduction, using filtration. Although, the body of work suggests that leukoreduction attenuates SIRS, discrepancies remain within the literature. The recent literature is reviewed highlighting the areas where concordance is lacking. In our study, on the basis of indirect indicators of SIRS, platelet function by thromboelastography biomaterial evaluation by light and scanning electron microscopy, we present our conclusions regarding clinical outcomes and the role of leukofiltration. © 2005 Bentham Science Publishers Ltd.

This Working Paper is intended as the first snapshot of a growing list of literature and materials accumulated at Laxenburg relevant to the study of national urban settlement systems and urban growth policies in advanced countries.

A man with chronic lymphocytic leukemia had a rapidly progressive five-lobe infiltrate of the lungs after treatment with 60 mg of bleomycin. He had previously been treated with adriamycin and cyclophosphamide. An open lung biopsy showed no evidence of an infection and was consistent with drug-induced injury. The patient improved dramatically with corticosteroid therapy.

Evaluating alternative sites for major constructed facilities requires comparing impacts of different levels and different types to establish desirable yet feasible balances. Currently employed and proposed, methodologies for evaluating the desirability of sets of impacts generated by large facilities are compared, and the theoretical assumptions implicit in each are discussed. In aggregate, the three sets of methodologies considered are Cost-Benefit Analysis and its various modifications, matrix or tableau methods of several sorts, and, preference theory (of which utility is a special case). Primary attention is given to the structure of objective functions defined over impacts.