7,007 research outputs found
In crowdfunding we trust : a trust-building model in lending crowdfunding
Trust critically affects the perceived probability of receiving expected returns on investment. Crowdfunding differs in many ways from traditional forms of investing. We have to ask what builds trust in this particular context. Based on literature regarding the formation of initial trust, we developed a model to explain which factors lead to crowdfunders’ trust in a crowdfunding project. We tested it on data collected from actual investors in a real project on a crowdlending platform. Our results show that trust in the crowdfunding platform and the information quality are more important factors of project trust than trust in the creator
Monolayer- and crystal-type MoO3 catalysts: Their catalytic properties in relation to their surface structures
Various MoO3 catalysts have been prepared by means of adsorption of molybdenum on supports from molybdate solutions or from the gas phase. Complete monomolecular layers of Mo6+ oxide can be prepared on the carriers Al2O3, Cr2O3, TiO2, CeO2, and ZrO2, whereas on SiO2 crystallites of MoO3 are formed. Reduction experiments show that the higher valencies of Mo are stabilized in the case of a monomolecular layer. Alcohol dehydration, pentene hydrogenation, and poisoning of these reactions with pyridine reveal that MoO2 present as a monolayer is less acidic than crystalline MoO2. On the complete monolayer catalysts investigated, mostly more than 70% of the dehydration and hydrogenation activities can be correlated with sites showing a relatively high acidity which are equivalent to 10–20% of the Mo content. The CO oxidation rates on the oxidized catalysts are antiparallel to those of the reactions on the reduced ones mentioned above; relatively basic sites preferentially chemisorb CO. The conclusion is that the activity pattern of the catalysts is a function of the acidity of the supports. It is suggested that Mo5+ ions contribute to the formation of the active acid sites after reduction with hydrogen
Which Globular Clusters contain Intermediate-mass Black Holes?
It has been assumed that intermediate-mass black holes (IMBHs) in globular
clusters can only reside in the most centrally concentrated clusters, with a
so-called `core-collapsed' density profile. While this would be a natural
guess, it is in fact wrong. We have followed the evolution of star clusters
containing IMBHs with masses between 125 \le M_{BH} \le 1000 M_{\odot} through
detailed N-body simulations, and we find that a cluster with an IMBH, in
projection, appears to have a relatively large `core' with surface brightness
only slightly rising toward the center. This makes it highly unlikely that any
of `core-collapsed' clusters will harbor an IMBH. On the contrary, the places
to look for an IMBH are those clusters that can be fitted well by
medium-concentration King models.
The velocity dispersion of the visible stars in a globular cluster with an
IMBH is nearly constant well inside the apparent core radius. For a cluster of
mass M_C containing an IMBH of mass M_{BH}, the influence of the IMBH becomes
significant only at a fraction 2.5 M_{BH}/M_C of the half-mass radius, deep
within the core, where it will affect only a small number of stars. In
conclusion, observational detection of an IMBH may be possible, but will be
challenging.Comment: 13 pages, 3 figures, Accepted ofr publication in ApJ (scheduled for
February 2005
Positivity bounds on gluon TMDs for hadrons of spin 1
We consider the transverse momentum dependent gluon distribution functions
(called gluon TMDs) by studying the light-front gluon-gluon correlator,
extending the results for unpolarized and vector polarized targets to also
include tensor polarized targets -- the latter type of polarization is relevant
for targets of spin . The light-front correlator includes
process-dependent gauge links to guarantee color gauge invariance. As from the
experimental side the gluon TMDs are largely unknown, we present positivity
bounds for combinations of leading-twist gluon distributions that may be used
to estimate their maximal contribution to observables. Since the gluonic
content of hadrons is particularly relevant in the small- kinematic region,
we also study these bounds in the small- limit for the dipole-type gauge
link structure using matrix elements of a single Wilson loop.Comment: 10 page
Quantum Critical Exponents for a Disordered Three-Dimensional Weyl Node
Three-dimensional Dirac and Weyl semimetals exhibit a disorder-induced
quantum phase transition between a semimetallic phase at weak disorder and a
diffusive-metallic phase at strong disorder. Despite considerable effort, both
numerically and analytically, the critical exponents and of this
phase transition are not known precisely. Here we report a numerical
calculation of the critical exponent using a minimal
single-Weyl node model and a finite-size scaling analysis of conductance. Our
high-precision numerical value for is incompatible with previous
numerical studies on tight-binding models and with one- and two-loop
calculations in an -expansion scheme. We further obtain
from the scaling of the conductivity with chemical potential
Reexamining the relation between debt mix and growth in Japan.
We propose a U-shaped relation between the relative weight of bank loans in total corporate debt and the firm's market-to-book ratio-a proxy for expected growth-which reconciles most existing theories. Using data on Japanese firms for 1983-97, we do find that, in the lower range of growth spectrum, firms with better prospects take more bonds in their debt mix: when the firm's prospects improve, the benefits from private debt initially fall relative to its costs. In contrast, in the higher range of growth, firms with more growth potentials take more monitored debt, reflecting, amongst other factors, the higher information and contracting costs of public debt faced by extreme growers. We can explain the seemingly conflicting evidence that Anderson and Makhija (1999) and Hoshi, Kashyap and Scharfstein (1993) provide in this respect. We also find that keiretsu firms do not behave significantly different from non-keiretsu ones, suggesting that keiretsu firms are fairly independent in their financing decisions and that extra costs and benefits from bank loans are either small or in reasonable balance. Firms that faced restrictions in issuing bonds, pre-1990, continue to behave differently from other firms long after the restrictions were lifted.
Topological equivalence of crystal and quasicrystal band structures
A number of recent articles have reported the existence of topologically
non-trivial states and associated end states in one-dimensional incommensurate
lattice models that would usually only be expected in higher dimensions. Using
an explicit construction, we here argue that the end states have precisely the
same origin as their counterparts in commensurate models and that
incommensurability does not in fact provide a meaningful connection to the
topological classification of systems in higher dimensions. In particular, we
show that it is possible to smoothly interpolate between states with
commensurate and incommensurate modulation parameters without closing the band
gap and without states crossing the band gap.Comment: 7 pages, 9 figures. Editors' Suggestio
- …