Information Aggregation in Standing and Ad Hoc Committees

[No abstract

Image versus Information: Changing Societal Norms and Optimal Privacy

We analyze the costs and benefits of using social image to foster virtuous behavior. A Principal seeks to motivate reputation-conscious agents to supply a public good. Each agent chooses how much to contribute based on his own mix of public-spiritedness, private signal about the value of the public good, and reputational concern for appearing prosocial. By making individual behavior more visible to the community the Principal can amplify reputational payoffs, thereby reducing free-riding at low cost. Because societal preferences constantly evolve, however, she knows only imperfectly both the social value of the public good (which matters for choosing her own investment, matching rate or legal policy) and the importance attached by agents to social esteem and sanctions. Increasing publicity makes it harder for the Principal to learn from what agents do (the "descriptive norm") what they really value (the "prescriptive norm"), thus presenting her with a tradeoff between incentives and information aggregation. We derive the optimal degree of privacy/publicity and matching rate, then analyze how they depend on the economy's stochastic and informational structure. We show in particular that in a fast-changing society (greater variability in the fundamental or the image-motivated component of average preferences), privacy should generally be greater than in a more static one

Aneurysm of sinus of valsalva

Aneurysm of sinus of Valsalva is a rare cardiac abnormality with congenital origin in most of the cases. If it is located in the right coronary sinus, it usually ruptures into a right heart chamber and frequently a ventricular septal defect (VSD) coexists with this condition. Early diagnosis and immediate surgical treatment can save the patient’s life in most cases. All the 3 cases reported in this series had aneurysm of right sinus of Valsalva with associated VSD and mild degree of aortic regurgitation (AR). Two of the cases ruptured aneurysm into the right ventricle. Trans-esophageal echocardiography was used to confirm the diagnosis and all three showed good results with surgery

3D-printed Synthetic Polymer Templates for Bone Tissue Engineering : Bulk Modifications and Osteoconduction Assessment

Syntetiske polymerbiomaterialer er enkle å bearbeide, biologisk inerte og brukes derfor i en rekke biomedisinske applikasjoner. Forskning har i lang tid fokusert på å øke biologiske aktivitet til slike materialers, og å tilpasse egenskapene til ulike bruksområder. Tredimensjonal (3D)-printing er velegnet til framstille biomaterialmaler med stor presisjon etter bestemte designparametre. Målet med denne avhandlingen var å undersøke 3D-printede syntetiske polymermaler for bruk til dyrkning og regenerasjon av beinvev (BTE). Undersøkelsene bestod av tre faser: Først ble det utført en systematisk litteraturundersøkelse for å analysere relevante faktorer ved bruk av 3D-printede, nedbrytbare maler og virkningen deres på beinregenerering i kraniale beindefekter hos ulike dyrearter (Studie I). En meta-analyse ble utført for å sammenligne nydannelse av bein for hver materialtype (polymerer, keramer eller kompositter). Man fant at effekten på beinregenereasjon var høyest hos kompositter bestående av polymerer og biokeramer, men også materialstrukturen gitt av 3D-printing. Parallelt ble det utført en studie på funksjonalisering av 3D-printede polykaprolakton (PCL) maler med gelatin (GL) som ble testet in vitro (Studie II). Til tross for at økt mengde GL (ved 8 og 16%) forbedret osteogen differensieringen av stamceller (fra rotter) ble malene ikke videreført på grunn av materialets lave strekkfasthet. I neste fase, ble poly(lactide-co-trimethylenecarbonate) (PLATMC) sammenlignet med PCL, og man fant at PLATMC hadde gunstigere både nedbrytnings- og mekaniske egenskaper enn PCL (studie III). I tillegg viste PLATMC seg bedre egnet for å fremme mineralisering av ekstracellulær matriks (ECM) fra humane stamceller in vitro. I en subkutan implantasjonsmodell i kanin (varighet 8 uker) var vertsresponsen på PLATMC mild, med innvekst av løst bindevevs og høy infiltrasjon av celler, der PCL bar preg av tett fibrøs vevsinnkapsling. Videre, når begge malene ble implantert i skallebensdefekter i kaniner, viste PLATMC-malene størst innvekst av bein. Det ble også funnet nydannelse av bein direkte på materialoverflaten, noe som hittil ikke beskrevet for syntetiske polymer. I tredje fasen valgte man å modifisere PLATMC ved å kombinere polymeren med hydroksapatitt (HA), et mineral og en viktig komponent i beinmasse. 3D-printede blandinger med ulike andeler HA (10, 30 og 50 %) ble sammenlignet med umodifisert PLATMC og testet for fysiske og biologiske egenskaper (Studie IV). Man fant at tilsatt HA reduserte strekkfastheten sammenlignet med ren PLATMC. HA10 viste noe redusert nedbrytningshastighet og lave nivåer av frigitt kalsium, mens de høye nedbrytningsprofilene til HA30 og HA50 ble tidlig ledsaget av omfattende frigivelse av kalsium. Ved bruk av stamceller (fra menneske) (in vitro), fant man for HA10 høyere mineralisering av ECM etter 14 og 21 dager enn for PLATMC alene, mens HA30 og HA50 ikke fremmet mineralisering i like stor grad. I tillegg viste HA30 og HA50 markant mindre beininnvekst når de ble implantert i skallebeinsdefekter i kaniner. Oppsummert fant man at umodifisert 3D-printet PLATMC fremmet mineralisering av ECM både in vitro og in vivo, men at man ved å tilsette HA i for store mengder, gjennom frigivelse av kalsium, forstyrrer denne prosessen i tillegg til å redusere materialets strekkfasthet. Resultatene fra disse studiene samlet støtter bruken av 3D-printede PLATMC-maler for beinregenerering.Synthetic polymer biomaterials are used in numerous biomedical applications providing biological inertness and ease of processing and shaping. Current research is directed towards boosting their biological activity, customized per application. 3D-printing is a promising technique for producing biomaterial templates with the required design parameters. The aim of the thesis was therefore to investigate the fabrication of osteoconductive 3D-printed synthetic polymer-based templates for bone tissue engineering (BTE). The investigation comprised three phases: In phase I, a literature survey was conducted, to review factors of relevance in applying potentially-degradable 3D-printed templates and their influence on bone regeneration in the calvarial bone defect (CBD) model, across various animal species (Study I). A meta-analysis was undertaken to compare the yield of new bone for each type of template material (polymer, ceramic or composites/blends). The highest impact on new bone formation was associated with the blended polymers and bioceramics, and the interconnected porosity generated by the 3D-printing. In parallel, an experimental study was undertaken on the functionalization of 3D-printed polycaprolactone (PCL) templates with gelatin (GL) due to its good biodegradation and biocompatibilty. Their physical and osteoconductive properties were tested in vitro (Study II). The biochemical compatibility contributed by GL (at 8 and 16%) improved the osteogenic differentiation of the seeded rat-BMSCs. However, this led to quite low tensile resistance and PCL/GL templates were therefore not studied in further in vivo trials. In phase II, poly(lactide-co-trimethylene carbonate) (PLATMC) was compared to PCL, and revealed that PLATMC had better degradation and mechanical properties than PCL (Study III), with prominent osteoconductivity and mineralized extracellular matrix (ECM) deposition (in vitro). In a subcutaneous implantation model in rabbits (8 weeks), the host response to PLATMC was mild, with loose connective tissue interface and high cellular invasion. In contrast, PCL was characterized by dense fibrous tissue encapsulation. When both templates were implanted in CBD in rabbits, PLATMC templates showed greater amount of new bone formation together with obvious contact osteogenesis presented on its surface, which was unique and unreported for a synthetic polymer before. In phase III, PLATMC was blended with hydroxyapatite (HA), in several ratios: 10 % HA (HA10), 30 % (HA30) and 50 % (HA50). Printability, physical, mechanical, and biological properties were compared (Study IV). The disclosed tensile properties of all 3D-printed HA blends were reduced, compared to PLATMC. HA10 showed reduced degradation and mild Ca release rate, while the high degradation profile of HA30 and HA50 was accompanied by massive early Ca release rates. On the biological aspect in vitro, using human-BMSCs seeded up to 28 days, HA10 disclosed higher mineralized ECM secretion at 14 and 21 days than PLATMC, while the osteoconductivity of HA30 and HA50 were markedly reduced and exhibited no advantages over pristine PLATMC templates. Moreover, HA30 and HA50, exhibited marked less osteoconductivity and reduced bone ingrowth when implanted in CBD. Thus high Ca release were correlated to reduced bone ingrowth and reduced osteoconduction, and the rate of Ca release should be considered in characterizing new HA-based templates. In summary, 3D-printed PLATMC showed promising osteoconductive activity, stimulating abundant mineralized ECM secretion in vitro, and demonstrated contact osteogenesis in vivo. However, the addition of HA reduced its tensile properties and high Ca release rates exhibited less osteoconductive properties than PLATMC. The results of these studies support the application of 3D-printed PLATMC templates for BTE.Doktorgradsavhandlin

Negotiating development: translocal gendered spaces in Muslim societies ; a methodology paper

Der Beitrag präsentiert und diskutiert den methodologischen Rahmen eines Forschungsprojektes zur Untersuchung der Verhandlung von Entwicklungskonzepten und -visionen in Südostasien sowie Ost- und Westafrika, die einen unterschiedlichen Grad des Islamisierungsprozesses aufweisen. Im Mittelpunkt stehen dabei der Kontext translokaler geschlechter-orientierter Räume der muslimischen Gesellschaften und die dort auftretenden Verbindungen bzw. Interaktionen zwischen den kulturellen Kategorien der muslimischen und der westlichen Welt. Das Aufeinandertreffen unterschiedlicher kultureller Ausrichtungen umfasst translokale Netzwerke von NGOs, Frauenbewegungen sowie -netzwerke, internationale Entwicklungsorganisationen bzw. -gruppen und deren Entwicklungskonzepte zu Menschenrechten, Armutsbekämpfung oder Geschlechtergleichheit. Die Ausführungen gliedern sich in die Erörterung der drei maßgeblichen methodologischen Vorgehensweisen zur Untersuchung der Lokalisation globaler Entwicklungskonzepte, die schließlich die Konstitution translokaler Räume in muslimischen Gesellschaften bewirken: (1) die soziologische Perspektive bei der empirischen Betrachtung der Verhandlung, (2) die wissenschaftliche Herangehensweise an den Forschungsgegenstand der Islamisierung durch eine translokal erzeugte Perspektive sowie (3) die Konstitution des Raumes im Kontext der Translokalität. (ICG

Appropriating the mosque: women's religious groups in Khartoum

'Seit der Machtübernahme der National Islamic Front (NIF) 1989 bildeten sich in den Moscheen der Hauptstadt des Sudan immer mehr Frauengruppen. Der vorliegende Beitrag vermittelt, auf welche Weise diese Moscheegruppen gesellschaftlichen Raum für Frauen herstellen, sich den religiös-öffentlichen, männlich bestimmten Raum der Moschee aneignen und ihn transformieren. Die Autorin betont, dieses Fallbeispiel der Moscheegruppen widerspreche der undifferenzierten Ansicht, Frauen in islamischen und speziell in islamistischen Ländern seien (notwendigerweise) unterdrückt und die Infragestellung ungleicher Geschlechterbeziehungen und Machtstrukturen setze eine Abwendung von der Religion voraus. Das Gegenteil sei der Fall: Frauen, die in Moscheegruppen aktiv sind, beanspruchen (mehr) Macht, indem sie religiös(er) werden. Sie transformieren öffentliche und religiöse Räume und handeln mit sozialen und religiösen Autoritäten und Institutionen geschlechtsspezifische Positionen aus.' (Autorenreferat)'This paper discusses the case of women's mosques groups in the capital of Sudan which have considerably spread since the National Islamic Front (NIF) seized power in 1989. The paper empirically demonstrates how the mosque groups are forming a social space for women and how this is leading to the appropriation and transformation of a public-religious and a highly masculine space such as the mosque. The main argument of the paper maintains that the case of the mosque groups contests the undifferentiated view that women in Islamic and specially Islamised societies are (necessarily) oppressed and that the only way to question the unequal gender relation and power structure is by getting away from religion. The paper asserts that, on the contrary, women active in mosque groups are claiming (more) power by becoming (more) religious. Through this power they constitute a space, transform public and religious ones and negotiate their gendered position vis-à-vis social and religious authorities and institutions.' (author's abstract)