The Social Capital of Venture Capitalists and Its Impact on the Funding of Start-Up Firms

How does the social capital of venture capitalists (VCs) affect the funding of start-ups? Extant entrepreneurship literature conceptualizes a substitute effect between the social and financial capital that new firms attain from their investors. On the contrary, by building on the rich social capital literature, we hypothesize a positive effect of VCs’ social capital, derived from past syndication, on the amount of money that start-ups receive. Specifically, we argue that both structural aspects of VCs’ social network, such as the number of connections and the spanning of structural holes, and relational aspects, such as the diversity of network partners’ attributes, provide VCs with superior access to information about current investment objects and opportunities to leverage them in the future, increasing their willingness to invest in these firms. Our empirical results, derived from a novel dataset containing more than 5,000 funding rounds in the Internet and IT sector, strongly confirm our hypotheses. Both structural and relational attributes of VCs’ syndication networks have a significant influence on the funds received by start-up firms, highlighting the importance of a social capital perspective on new venture funding. We discuss the implications of our findings for theories of venture capital and entrepreneurship, showing that the role and effect of VCs’ social capital on start-up firms is much more complex than previously argued in the literature.social networks;social capital;start-ups;venture capital;structural holes

Self-Consistent Response of a Galactic Disk to an Elliptical Perturbation Halo Potential

We calculate the self-consistent response of an axisymmetric galactic disk perturbed by an elliptical halo potential of harmonic number m = 2, and obtain the net disk ellipticity. Such a potential is commonly expected to arise due to a galactic tidal encounter and also during the galaxy formation process. The self-gravitational potential corresponding to the self-consistent, non-axisymmetric density response of the disk is obtained by inversion of Poisson equation for a thin disk. This response potential is shown to oppose the perturbation potential, because physically the disk self-gravity resists the imposed potential. This results in a reduction in the net ellipticity of the perturbation halo potential in the disk plane. The reduction factor denoting this decrease is independent of the strength of the perturbation potential, and has a typical minimum value of 0.75 - 0.9 for a wide range of galaxy parameters. The reduction is negligible at all radii for higher harmonics (m > or = 3) of the halo potential. (abridged).Comment: 26 pages (LaTex- aastex style), 3 .eps figures. To appear in the Astrophysical Journal, Vol. 542, Oct. 20, 200

Nonflammable, antistatic, and heat-sealable film

Antistatic, heat-sealable, nonflammable films prepared from polyvinylidene fluoride and polyvinylidene chloride resin

Radial HI Profiles at the Periphery of Galactic Disks: The Role of Ionizing Background Radiation

Observations of neutral hydrogen in spiral galaxies reveal a sharp cutoff in the radial density profile at some distance from the center. Using 22 galaxies with known HI distributions as an example, we discuss the question of whether this effect can be associated exclusively with external ionizing radiation, as is commonly assumed. We show that before the surface density reaches $\sigma_{\textrm{HI}}\le 0.5 {\cal M}_\odot/{\textrm {pc}}^2$(the same for galaxies of different types), it is hard to expect the gas to be fully ionized by background radiation. For two of 13 galaxies with a sharp drop in the HI profile, the "steepening" can actually be caused by ionization. At the same time, for the remaining galaxies, the observed cutoff in the radial HI profile is closer to the center than if it was a consequence of ionization by background radiation and, therefore, it should be caused by other factors.Comment: 15 pages, 6 figure

Low frequency m=1 normal mode oscillations of a self-gravitating disc

A continuous system such as a galactic disc is shown to be well approximated by an N-ring differentially rotating self-gravitating system. Lowest order (m=1) non-axisymmetric features such as lopsidedness and warps are global in nature and quite common in the discs of spiral galaxies. Apparently these two features of the galactic discs have been treated like two completely disjoint phenomena. The present analysis based on an eigenvalue approach brings out clearly that these two features are fundamentally similar in nature and they are shown to be very Low frequency Normal Mode (LNM) oscillations manifested in different symmetry planes of the galactic disc. Our analysis also show that these features are actually long-lived oscillating pattern of the N-ring self-gravitating system.Comment: 5 figures. Accepted for publication in MNRAS Letter

The Schumpeterian Entrepreneur: A Review of the Empirical Evidence on the Antecedents, Behavior, and Consequences of Innovative Entrepreneurship

Innovative entrepreneurship is considered an important pillar for economic development and has sparked a lively discussion in academia and practice alike. Oftentimes, however, the debate is not sufficiently grounded on solid empirical evidence. The academic literature is growing but very scattered and is separated into several disciplines. We provide a summary that takes stock of the academic knowledge about innovative entrepreneurship and summarizes the evidence from 102 empirical studies published in the primary economics and management journals on the antecedents, behavior, and consequences of innovative entrepreneurship. Based on this state-of-the-art literature review, directions for future research are discussed

A 340 kDa hyaluronic acid secreted by human vascular smooth muscle cells regulates their proliferation and migration

The formation of atherosclerotic lesions is characterized by invasion of vascular smooth muscle cells (VSMC) into the tunica intima of the arterial wall and subsequently by increased proliferation of VSMC, a process apparently restricted to the intimal layer of blood vessels. Both events are preceded by the pathological overexpression of several growth factors, such as platelet-derived growth factor (PDGF) which is a potent mitogen for VSMC and can induce their chemotaxis. PDGF is generally not expressed in the normal artery but it is upregulated in atherosclerotic lesions. We have previously shown that PDGF-BB specifically stimulates proliferating VSMC to secrete a 340 kDa hyaluronic acid (HA-340). Here, we present evidence regarding the biological functions of this glycan. We observed that HA-340 inhibited the PDGF-induced proliferation of human VSMC in a dosedependent manner and enhanced the PDGF-dependent invasion of VSMC through a basement membrane barrier. These effects were abolished following treatment of HA-340 with hyaluronidase. The effect of HA-340 on the PDGF-dependent invasion of VSMC coincided with increased secretion of the 72-kDa type IV collagenase by VSMC and was completely blocked by GM6001, a hydroxamic acid inhibitor of matrix metalloproteinases. HA-340 did not exert any chemotactic potency, nor did it affect chemotaxis of VSMC along a PDGF gradient. In human atheromatic aortas, we found that HA-340 is expressed with a negative concentration gradient from the tunica media to the tunica intima and the atheromatic plaque. Our findings suggest that HA-340 may be linked to the pathogenesis of atherosclerosis, by modulating VSMC proliferation and invasio

Delayed clusters accompanying nonmesonic weak decay of the Λ\Lambda-hypernuclei: a clue to nonleptonic processes

The nonmesonic decay of $\Lambda$-hypernuclei provides access to the nonleptonic weak decay process $\Lambda N \to NN$, which is achievable only through the observation of hypernuclear ground-state decays. We continue the discussion of some specific cases which make it possible to detect a few exclusive transitions, namely, the stripping of nucleon from the ground state results in a resonance state decaying via emission of two clusters. Delayed clusters accompanying weak decay of light hypernuclei give a unique information on spin dependence of the weak decay matrix elements.Comment: Presented at International Bogolyubov Conference "Problems of Theoretical and Mathematical Physics" (dedicated to the 100th anniversary of the birth of N.N.~Bogolyubov) Dubna, Russia, August 21 - 27, 200