2,752 research outputs found
The Economics of Conflicts of Interest in Financial Institutions
A conflict of interest exists when a party to a transaction could potentially make a gain from taking actions that are detrimental to the other party in the transaction. This paper examines the economics of conflicts of interest in financial institutions and reviews the growing empirical literature (mostly focused on analysts) on the economic implications of these conflicts. Economic analysis shows that, although conflicts of interest are omnipresent when contracting is costly and parties are imperfectly informed, there are important factors that mitigate their impact and, strikingly, it is possible for customers of financial institutions to benefit from the existence of such conflicts. The empirical literature reaches conclusions that differ across types of conflicts of interest, but overall these conclusions are more ambivalent and certainly more benign than the conclusions drawn by journalists and politicians from mostly anecdotal evidence. Though much has been made of conflicts of interest arising from investment banking activities, there is no consensus in the empirical literature supporting the view that conflicts resulting from these activities had a systematic adverse impact on customers of financial institutions.
The effect of gag reflex on cardiac sympatovagal tone
Objectives: Heart velocity may be influenced by gagging. The medulla oblongata receives the afferents of gag reflex. Neuronal pools of vomiting, salivation and cardiac parasympathetic fibers are very close in this area. So, their activities may be changed by spillover from each other. Using the heart rate variability (HRV) analysis, the effect of gagging on cardiac sympatovagal balance was studied. Methods: ECG was recorded from 9 healthy nonsmoker volunteer students for 10 minutes in the sitting position between 10 and 11 AM. Gagging was elicited by tactile stimulation of the posterior pharyngeal wall. At 1 kHz sampling rate, HRV was calculated. The mean of heart rate at low and high frequencies (LF: 0.04-0.15; HF: 0.15-0.4 Hz) were compared before and after the stimulus. Results: The mean of average heart rate, LF and HF in normalized units (nu) and the ratio of them (LF/HF) before and after the gagging were 89.9 ± 3 and 95.2 ± 3 bpm; 44.2 ± 5.8 and 21.2 ± 4; 31.1 ± 5.3 and 39.4 ± 3.8; and 1.7 ± 0.3 and 0.6 ± 0.2 respectively. Conclusion: Gagging increased heart velocity and had differential effect on two branches of cardiac autonomic nerves. The paradoxical relation between average heart rate and HRV indexes of sympatovagal tone may be due to unequal rate of change in autonomic fiber activities which is masked by 5 minutes interval averaging. © OMSB, 2012
Non-equilibrium forces following quenches in active and thermal matter
Non-equilibrium systems are known to exhibit long-ranged correlations due to
conservation of quantities like density or momentum. This, in turn, leads to
long-ranged fluctuation-induced (Casimir) forces, predicted to arise in a
variety of non-equilibrium settings. Here, we study such forces, which arise
transiently between parallel plates or compact inclusions in a gas of
particles, following a change ("quench") in temperature or activity of the
medium. Analytical calculations, as well as numerical simulations of passive or
active Brownian particles, indicate two distinct forces: (i) The immediate
effect of the quench is adsorption or desorption of particles of the medium to
the immersed objects, which in turn initiates a front of relaxing (mean)
density. This leads to time-dependent {\it density-induced forces}. (ii) A
long-term effect of the quench is that density fluctuations are modified,
manifested as transient (long-ranged) (pair-)correlations that relax
diffusively to their (short-ranged) steady-state limit. As a result, transient
{\it fluctuation-induced forces} emerge. We discuss the properties of
fluctuation-induced and density-induced forces as regards universality,
relaxation as a function of time, and scaling with distance between objects.
Their distinct signatures allow us to distinguish the two types of forces in
simulation data. Finally, we propose several scenarios for their experimental
observation.Comment: - Added Journal reference and DOI - Modified title - Fixed minor
typos - Added plot of Eq. (32) [16 pages, 11 figures
Collapse of Randomly Linked Polymers
We consider polymers in which M randomly selected pairs of monomers are
restricted to be in contact. Analytical arguments and numerical simulations
show that an ideal (Gaussian) chain of N monomers remains expanded as long as
M<<N. This result is inconsistent with results obtained from free energy
considerations by Brygelson and Thirumalai (PRL76, 542 (1996)).Comment: 1 page, 1 postscript figure, LaTe
Melting of persistent double-stranded polymers
Motivated by recent DNA-pulling experiments, we revisit the Poland-Scheraga
model of melting a double-stranded polymer. We include distinct bending
rigidities for both the double-stranded segments, and the single-stranded
segments forming a bubble. There is also bending stiffness at the branch points
between the two segment types. The transfer matrix technique for single
persistent chains is generalized to describe the branching bubbles. Properties
of spherical harmonics are then exploited in truncating and numerically solving
the resulting transfer matrix. This allows efficient computation of phase
diagrams and force-extension curves (isotherms). While the main focus is on
exposition of the transfer matrix technique, we provide general arguments for a
reentrant melting transition in stiff double strands. Our theoretical approach
can also be extended to study polymers with bubbles of any number of strands,
with potential applications to molecules such as collagen.Comment: 9 pages, 7 figure
Probability distributions for polymer translocation
We study the passage (translocation) of a self-avoiding polymer through a
membrane pore in two dimensions. In particular, we numerically measure the
probability distribution Q(T) of the translocation time T, and the distribution
P(s,t) of the translocation coordinate s at various times t. When scaled with
the mean translocation time , Q(T) becomes independent of polymer length,
and decays exponentially for large T. The probability P(s,t) is well described
by a Gaussian at short times, with a variance that grows sub-diffusively as
t^{\alpha} with \alpha~0.8. For times exceeding , P(s,t) of the polymers
that have not yet finished their translocation has a non-trivial stable shape.Comment: 5 pages, 4 figure
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