Abstract:
Total hip or knee replacement is effective in improving joint function, quality of life, and pain reduction. The oldest old population with joint replacements (TJR) is underrepresented in current literature. We compared health-related and functional characteristics of oldest olds with and without TJR. Participants (aged 85 years) were divided into a group with and without TJR. Comorbidity, physical and joint functioning, daily living activities, quality of life, and mortality were recorded. Thirty-eight of 599 participants (6.3%) received a TJR in the past. Participants with a TJR had slightly less comorbidities, walked slower ( ？？ = 0 . 0 0 6 ), and complained more about hip-pain ( ？？ = 0 . 0 0 7 ). Mortality of those with a TJR was lower during the first 8-year followup ( ？？ = 0 . 0 4 ). All other characteristics were comparable between groups. We conclude that subjects with a TJR performed equally well, besides showing a lower gait speed and a higher frequency of hip-pain. Except for the lower gaitspeed, having a TJR is not associated with poorer health. 1. Introduction The population of oldest olds (i.e., 85 years and older) is the fastest growing segment of the elderly population in the western society [1]. The health status decreases with increasing chronological age [2]. One of the major age-related diseases is osteoarthritis (OA), which is more common in females [3–5]. In subjects between 60 and 70 years of age, prevalences of symptomatic knee OA are reported of approximately 10 percent in males and 20 percent in females [4]. Prevalence of knee OA is comparable in subjects aged 80 years and older [4, 5]. Symptomatic OA of the hip is present in approximately five percent of the 60 to 70 years old females and up to 18 percent in females of 80 years and older. In males, prevalences are slightly lower [3, 4]. Due to the demographic changes, the number of total hip replacement (THR) and total knee replacement (TKR) procedures steadily increases [6]. Increasing age is associated with a higher complication and mortality rate after total joint replacement [6]. However, the results of total joint replacement in elderly patients have been proven effective in terms of pain reduction, functional improvement, and cost-effectiveness and show similar results compared to younger patients receiving total joint replacement [7, 8]. OA of the hip or the knee impairs physical activity [4]. Restriction of physical activity is associated with numerous detrimental effects on general health status, physical function, and quality of life [4, 9]. Maintaining physical

Abstract:
Let A be the moduli space of principally polarized abelian varieties of dimension 4 over an algebraically closed field k of characteristic different from 2,3. It is proved that the universal principally polarized abelian variety over A, as well as the universal theta divisor over A, are unirational varieties.

Abstract:
Let S be a general complex Nikulin surface of genus 8, a geometric construction of S is given as follows. Consider a smooth 3-fold linear section T of the Grassmannian G(1,4) and the Hilbert scheme of rational normal sextic curves of T. In it consider the special family of sextics A which are also contained in the congruence of bisecant lines to a rational normal quartic curve of P^4. We show that S is biregular to a quadratic section of T containing a sextic A. In particular A admits a 1-dimensional family of bisecant lines contained in G(1,4) and 8 of them are in S. This explicit construction is then used to prove that the moduli space of genus 8 Nikulin surfaces is rational.

Abstract:
Refereed version to appear on Journal of Algebraic Geometry. Unchanged content. Strongly ameliorated presentation thanks to referee's action.

Abstract:
The paper aims to give an account, both historical and geometric, on the diverse geography of rational parametrizations of moduli spaces related to curves. It is a contribution to the book Handbook of Moduli, editors G. Farkas and I. Morrison, to be published by International Press. Refereed version.

Abstract:
Let U(r) be the moduli space of rank r vector bundles with trivial determinant on a smooth curve of genus 2. The map theta_r: U(r) -> |r Theta|, which associates to a general bundle its theta divisor, is generically finite. In this paper we give a geometric interpretation of the generic fibre of theta_r.

Abstract:
We describe the birational geometry of the moduli space S_g^{-} of odd spin curves (theta-characteristics) for all genera g. The odd spin moduli space is a uniruled variety for g<12, and of general type for g at least 12. Furthermore, for g<9 we use the existence of Mukai models of the moduli space of curves, to prove that S_g^{-} is unirational. Our results show that in genus 8, the odd spin moduli space in unirational, whereas its even counterpart is of Calabi-Yau type.

Abstract:
We carry out a complete birational classification of the universal theta divisor Th_g over the moduli space of curves of genus g, and show that Th_g enjoys good rationality properties for g<12, and is a variety of general type for g\geq 12. The key ingredient is an intersection-theoretic study of the universal antiramification locus of the Gauss map. We also present a complete classification of the universal symmetric product of degree g-2 over M_g.