Aging Populations and Social Challenges. Paper presented on IIASA's 20th Anniversary

IIASA celebrated its twentieth anniversary on May 12-13 with its fourth general conference, IIASA '92: An International Conference on the Challenges to Systems Analysis in the Nineties and Beyond. The conference focused on the relations between environment and development and on studies that integrate the methods and findings of several disciplines. The role of systems analysis, a method especially suited to taking account of the linkages between phenomena and of the hierarchical organization of the natural and social world, was also assessed, taking account of the implications this has for IIASA's research approach and activities. This paper is one of six IIASA Collaborative Papers published as part of the report on the conference, an earlier instalment of which was Science and Sustainability, published in 1992. If there is anyone who writes with authority on pensions and the problems that all industrial countries will confront in at most the next 20 years it is Professor van Praag. He has been far ahead of his time in pointing out the fatal defect hidden in the present arrangement of social security. It was introduced and is now maintained and defended less from the viewpoint of long-term workability than for its short term convenience. The system I refer to is called Pay As You Go (PAYG), wherein no reserve is maintained; each year's tax collections (necessarily from those working) are paid out that same year to those retired. The convenience of PAYG was that as soon as announced it could start to pay retirees almost irrespective of the amounts they had contributed. It necessarily reduces saving in the economy, turns one generation against the preceding generation, and has other incidental ill-effects, but these are not what concern van Praag and Dalen most. What they fear is its instability in the face of demographic fluctuations, specifically the day when the postwar baby boom starts to retire. Subsequent to the baby boom of the 1950s birth rates went down and stayed down, so that the cohorts to pay the pensions will be relatively small, just as the cohorts coming to collect them will attain record size. Beyond that fact, caused by the changing birth rate, is the decline in mortality, the increased fraction of each cohort living to extreme old age. What happens when these facts require that payroll taxes go up to the 25 percent of all wages that will ultimately be necessary if the retired are to have social security incomes equal to 80 percent of the average wage? PAYG depends on each generation as it makes its payments trusting that the next generation will continue do the same; once doubt starts to spread the fragility of the whole system is revealed. We are told that the system is supported by a "contract between the generations" but the "contract" is metaphorical, as will be revealed in a few years when the crunch comes. Effects go beyond the social security system; they create a wholly artificial and unnecessary conflict between the generations. With PAYG a shortsighted younger generation can become alarmed at what is ultimately good news for all - the rapidly growing number of octogenarians and people even older - and be tempted to vote against further use of their taxes for research into and therapy of the chronic diseases of old age. But you do not require my explanation of the problem of PAYG. You not only have it better expressed by van Praag and Dalen, but they provide a remedy, one that will be the more painless the sooner it is initiated

Relativistic Effects in Nuclear Matter and Nuclei

The status of relativistic nuclear many-body calculations of nuclear systems to be built up in terms of protons and neutrons is reviewed. In detail, relativistic effects on several aspects of nuclear matter such as the effective mass, saturation mechanism, and the symmetry energy are considered. This review will especially focus on isospin asymmetric issues, since these aspects are of high interest in astrophysical and nuclear structure studies. Furthermore, from the experimental side these aspects are experiencing an additional boost from a new generation of radioactive beam facilities, e.g. the future GSI facility FAIR in Germany or SPIRAL2 at GANIL/France. Finally, the prospects of studying finite nuclei in microscopic calculations which are based on realistic $NN$ interactions by including relativistic effects in calculations of low momentum interactions are discussed.Comment: 57 pages, 16 figure

Separable form of low-momentum realistic NN interaction

The low-momentum interaction $V_{\text{low-k}}$ derived from realistic models of the nucleon-nucleon interaction is presented in a separable form. This separable force is supported by a contact interaction in order to achieve the saturation properties of symmetric nuclear matter. Bulk properties of nuclear matter and finite nuclei are investigated for the separable form of $V_{\text{low-k}}$ and two different parameterizations of the contact term. The accuracy of the separable force in Hartree-Fock calculations with respect to the original interaction $V_{\text{low-k}}$ is discussed. For a cutoff parameter $\Lambda$ of 2 fm$^{-1}$ a representation by a rank 2 separable force yields a sufficient accuracy, while higher ranks are required for larger cut-off parameters. The resulting separable force is parameterized in a simple way to allow for an easy application in other nuclear structure calculations.Comment: 11 pages, 7 figure

Alternative antibody for the detection of CA125 antigen: a European multicenter study for the evaluation of the analytical and clinical performance of the Access (R) OV Monitor assay on the UniCel (R) Dxl 800 Immunoassay System

Background: Cancer antigen CA125 is known as a valuable marker for the management of ovarian cancer. Methods: The analytical and clinical performance of the Access OV Monitor Immunoassay System (Beckman Coulter) was evaluated at five different European sites and compared with a reference system, defined as CA125 on the Elecsys System (Roche Diagnostics). Results: Total imprecision (%CV) of the OV Monitor ranged between 3.1% and 8.8%, and inter-laboratory reproducibility between 4.7% and 5.0%. Linearity upon dilution showed a mean recovery of 100% (SD+8.1%). Endogenous interferents had no influence on OV Monitor levels (mean recoveries: hemoglobin 107%, bilirubin 103%, triglycericles 103%). There was no high-dose hook effect up to 27,193 kU/L. Clinical performance investigated in sera from 1811 individuals showed a good correlation between the Access OV Monitor and Elecsys CA125 (R = 0.982, slope = 0.921, intercept = + 1.951). OV Monitor serum levels were low in healthy individuals (n = 267, median = 9.7 kU/L, 95th percentile = 30.8 kU/L), higher in individuals with various benign diseases (n = 549, medians = 10.9-16.4 kU/L, 95th percentiles = 44.2-355 kU/L) and even higher in individuals suffering from various cancers (n = 995, medians= 12.4-445 kU/L; 95th percentiles = 53.4-4664 kU/L). Optimal diagnostic accuracy for cancer detection against the relevant benign control group by the OV Monitor was found for ovarian cancer {[}area under the curve (AUC) 0.898]. Results for the reference CA125 assay were comparable (AUC 0.899). Conclusions: The Access OV Monitor provides very good methodological characteristics and demonstrates an excellent analytical and clinical correlation with Elecsys CA125. The best diagnostic accuracy for the OV Monitor was found in ovarian cancer. Our results also suggest a clinical value of the OV Monitor in other cancers

Stad en land in een nieuwe geografie; maatschappelijke veranderingen en ruimtelijk dynamiek

Political Scienc

Differential Expression of Proinflammatory Cytokines and Their Inhibitors during the Course of Meningococcal Infections

Circulating concentrations of tumor necrosis factor-α (TNF), interleukin (IL)-1β, IL-6, IL-1 receptor antagonist (IL-1ra), and soluble TNF receptors p55 (sTNFr-55) and p75 (sTNFr-75) and ex vivo production ofTNF, IL-1, IL-6, and IL-1ra using a whole blood culture system were measured during the acute and convalescent stages of meningococcal infection. Circulating TNF and IL-1 were below detection level, whereas IL-6 and IL-1ra, sTNFr-55, and sTNFr-75 were increased at admission. The ex vivo production of proinflammatory cytokines TNF, IL-1, and IL-6 was suppressed at admission and restored gradually during recovery. On the contrary, the production of the antiinflammatory IL-1ra was increased at admission. The elevated concentrations of both IL-1ra and sTNFr early in the course of infection suggest a regulatory role for these antiinflammatory compounds. The observed down-regulation of the ex vivo production of TNF, IL-1, and IL-6 and up-regulation of the production of IL-1 ra in the acute stage may indicate a protective regulation mechanis