Reciprocity, Exchange and Redistribution. An experimental investigation inspired by Karl Polanyi’s The Economy as Instituted Process

Inspired by Karl Polanyi’s writings on three allocation modes, namely reciprocity, exchange and redistribution, we first tested a reciprocity ring with ten players. The baseline treatment, with no possibility of socialisation, displayed very low levels of allocative efficiency. Consistently with the Polanyian approach to reciprocity, we found that inducing the notion of symmetry among the players increased efficiency levels significantly. We then simulated a market exchange, with significant allocative efficiency gains. We conclude that indirect-reciprocity rings among anonymous players can seldom function in the absence of definite institutional refinements, promoting forms of symmetry-acknowledgement.Reciprocity, Redistribution, Exchange, Comparative Institutional Analysis.

Joint formation of bright quasars and elliptical galaxies in the young Universe

We show that the mass function of black holes expected from the past quasar activity (both visible and obscured) is consistent with the number of dormant black holes found in the bulges of nearby galaxies. The joint formation of quasars and bulges is addressed by means of an analytical model for galaxy formation, based on the hierarchical clustering of cold dark matter halos. The model is able to reproduce the main statistical properties of both populations under the hypotheses that (i) star formation and quasar shining follow an anti-hierarchical order, and (ii) galaxy morphology and final black hole mass are determined by the same physical process.Comment: 5 pages, 3 postscript figures included, proceedings of the IGRAP meeting "Clustering at high redshift", Marseille, June 199

Stability analysis of abstract systems of Timoshenko type

We consider an abstract system of Timoshenko type $$\begin{cases} \rho_1{{\ddot \varphi}} + a A^{\frac12}(A^{\frac12}\varphi + \psi) =0\\ \rho_2{{\ddot \psi}} + b A \psi + a (A^{\frac12}\varphi + \psi) - \delta A^\gamma {\theta} = 0\\ \rho_3{{\dot \theta}} + c A\theta + \delta A^\gamma {{\dot \psi}} =0 \end{cases}$$ where the operator $A$ is strictly positive selfadjoint. For any fixed $\gamma\in\mathbb{R}$, the stability properties of the related solution semigroup $S(t)$ are discussed. In particular, a general technique is introduced in order to prove the lack of exponential decay of $S(t)$ when the spectrum of the leading operator $A$ is not made by eigenvalues only.Comment: Corrected typo

Evidence for a Massive Dark Object in NGC 4350

In this work we build a detailed dynamic model for a S0 galaxy possibly hosting a central massive dark object (MDO). We show that the photometric profiles and the kinematics along the major and minor axes, including the h3 and h4 profiles, imply the presence of a central MDO of mass M = 1.5 - 9.7 10^8 solar masses, i.e. 0.3-2.8% of the mass derived for the stellar spheroidal component. Models without MDO are unable to reproduce the kinematic properties of the inner stars and of the rapidly rotating nuclear gas. The stellar population comprise of an exponential disc (27% of the light) and a diffuse spheroidal component (73% of the light) that cannot be represented by a simple de Vaucouleurs profile at any radius. The M/L ratios we found for the stellar components (respectively 3.3 and 6.6) are typical of those of disc and elliptical galaxies.Comment: 9 pages, 4 encapsulated postscript figures. Requires mn.sty, psfig.sty. Accepted for publication in MNRA

CMB Distortions from Superconducting Cosmic Strings

We reconsider the effect of electromagnetic radiation from superconducting strings on cosmic microwave background (CMB) mu- and y-distortions and derive present (COBE-FIRAS) and future (PIXIE) constraints on the string tension, mu_s, and electric current, I. We show that absence of distortions of the CMB in PIXIE will impose strong constraints on mu_s and I, leaving the possibility of light strings (G mu_s < 10^{-18}) or relatively weak currents (I < 10 TeV).Comment: 10pages, 5 figures, Submitted to PRD, v2:References added, replaced to match the PRD versio

Spectroscopic Confirmation of the Cl 1604 Supercluster at z~0.9

We present spectroscopic confirmation of the Cl 1604 supercluster at z~0.9. Originally detected as two individual clusters, Cl 1604+4304 at z = 0.90 and Cl 1604+4321 at z = 0.92, which are closely separated in both redshift and sky position, subsequent imaging revealed a complex of red galaxies bridging the two clusters, suggesting that the region contained a large scale structure. We have carried out extensive multi-object spectroscopy, which, combined with previous measurements, provides ~600 redshifts in this area, including 230 confirmed supercluster members. We detect two additional clusters that are part of this structure, Cl 1604+4314 at z = 0.87 and Cl 1604+4316 at z = 0.94. All four have properties typical of local clusters, with line-of-sight velocity dispersions between 489 and 962 km/s. The structure is significantly extended in redshift space, which, if interpreted as a true elongation in real space, implies a depth of 93 Mpc. We examine the spatial and redshift distribution of the supercluster members.Comment: Accepted to ApJ Letters. 4 pages with 3 figure

Mass function of dormant black holes and the evolution of the Active Galactic Nuclei

We derive the mass function of the relic black holes and compared with that of the Massive Dark Objects in galaxies. Under the assumption that accretion onto massive BH's powers the Active Galactic Nuclei, the mass function of the BH responsibile for the past activity of QSO/AGN is computed. Our results support the scenario in which the QSO phase has exclusively occurred in every proto-elliptical.Comment: 10 pages, 8 Figures. Version improved with referee comments. J. Accepted on MNRA

Enhanced platelet adhesion induces angiogenesis in intestinal inflammation and inflammatory bowel disease microvasculature

Although angiogenesis is viewed as a fundamental component of inflammatory bowel disease (IBD) pathogenesis, we presently lack a thorough knowledge of the cell type(s) involved in its induction and maintenance in the inflamed intestinal mucosa. This study aimed to determine whether platelet (PLT) adhesion to inflamed intestinal endothelial cells of human origin may favour angiogenesis. Unstimulated or thrombin-activated human PLT were overlaid on resting or tumour necrosis factor (TNF)-α-treated human intestinal microvascular endothelial cells (HIMEC), in the presence or absence of blocking antibodies to either vascular cell adhesion molecule (VCAM)-1, intercellular adhesion molecule (ICAM)-1, integrin αvβ3, tissue factor (TF) or fractalkine (FKN). PLT adhesion to HIMEC was evaluated by fluorescence microscopy, and release of angiogenic factors (VEGF and soluble CD40L) was measured by ELISA. A matrigel tubule formation assay was used to estimate PLT capacity to induce angiogenesis after co-culturing with HIMEC. TNF-α up-regulated ICAM-1, αvβ3 and FKN expression on HIMEC. When thrombin-activated PLT were co-cultured with unstimulated HIMEC, PLT adhesion increased significantly, and this response was further enhanced by HIMEC activation with TNF-α. PLT adhesion to HIMEC was VCAM-1 and TF independent but ICAM-1, FKN and integrin αvβ3 dependent. VEGF and sCD40L were undetectable in HIMEC cultures either before or after TNF-α stimulation. By contrast, VEGF and sCD40L release significantly increased when resting or activated PLT were co-cultured with TNF-α-pre-treated HIMEC. These effects were much more pronounced when PLT were derived from IBD patients. Importantly, thrombin-activated PLT promoted tubule formation in HIMEC, a functional estimate of their angiogenic potential. In conclusion, PLT adhesion to TNF-α-pre-treated HIMEC is mediated by ICAM-1, FKN and αvβ3, and is associated with VEGF and sCD40L release. These findings suggest that inflamed HIMEC may recruit PLT which, upon release of pro-angiogenic factors, actively contribute to inflammation-induced angiogenesis