11,507 research outputs found
The Electrochemical Oxidation of Substituted Catechols
The oxidation of substituted catechols was studied by cyclic voltammetry, chronoamperometry, rotating ringâdisk electrode, and coulometry. The results showed that the quinones that were formed from the oxidation of substituted catechols reacted with the basic forms of the starting material to yield the dimeric product. These products were generally unstable and rapidly polymerized or underwent some other irreversible reaction to form an electroinactive product. For 3,4âdihydroxyacetophenone and propriophenone, the intermediate was stable long enough to be observed in cyclic voltammetry. The rate of the coupling reaction was found to correlate well with the Hammett ÏâÏ parameters and indicated that there was substantial negative charge in the transition state. Finally, an analysis of the coulometric nâvalues along with the iat1/2/C values indicated that the initial coupling product was a diphenyl ether. Analysis of the coulometry products showed extensive polymerization
ACCOUNTING STANDARDS AND EARNINGS MANAGEMENT AROUND THE WORLD
This study investigates the relation between accounting standards and earnings management around the world. I find that international accounting standards, accrual-based accounting standards, accounting standards with increased disclosure requirements, and separating tax and financial reporting all constrain earnings management. Following previous studies, I treat accounting standard measures as being endogenous, and use instrumental variables to re-estimate the model. I find consistent results. I conclude that accounting standard policy is an important institution in determining the quality of reported financial information. Different from prior international earnings management studies, I directly test whether international firms are managing earnings using the distribution method. I find evidence that firms are managing reported earnings around the world. I also document that high-quality accounting standards decrease analyst forecast error
Log-Harnack Inequality for Stochastic Differential Equations in Hilbert Spaces and its Consequences
A logarithmic type Harnack inequality is established for the semigroup of
solutions to a stochastic differential equation in Hilbert spaces with
non-additive noise. As applications, the strong Feller property as well as the
entropy-cost inequality for the semigroup are derived with respect to the
corresponding distance (cost function)
All Reviews are Not Created Equal: The Disaggregate Impact of Reviews and Reviewers at Amazon.com
Observing the Formation of Long-range Order during Bose-Einstein Condensation
We have experimentally investigated the formation of off-diagonal long-range
order in a gas of ultracold atoms. A magnetically trapped atomic cloud prepared
in a highly nonequilibrium state thermalizes and thereby crosses the
Bose-Einstein condensation phase transition. The evolution of phase coherence
between different regions of the sample is constantly monitored and information
on the spatial first-order correlation function is obtained. We observe the
growth of the spatial coherence and the formation of long-range order in real
time and compare it to the growth of the atomic density. Moreover, we study the
evolution of the momentum distribution during the nonequilibrium formation of
the condensate.Comment: 4 pages, 4 figure
Excitonic condensate and quasiparticle transport in electron-hole bilayer systems
Bilayer electron-hole systems undergo excitonic condensation when the
distance d between the layers is smaller than the typical distance between
particles within a layer. All excitons in this condensate have a fixed dipole
moment which points perpendicular to the layers, and therefore this condensate
of dipoles couples to external electromagnetic fields. We study the transport
properties of this dipolar condensate system based on a phenomenological model
which takes into account contributions from the condensate and quasiparticles.
We discuss, in particular, the drag and counterflow transport, in-plane
Josephson effect, and noise in the in-plane currents in the condensate state
which provides a direct measure of the superfluid collective-mode velocity.Comment: 7 pages, 3 figure
Structural and Energetic Determinants of Apo Calmodulin Binding to the IQ Motif of the NaV1.2 Voltage-Dependent Sodium Channel
SummaryThe neuronal voltage-dependent sodium channel (Nav1.2), essential for generation and propagation of action potentials, is regulated by calmodulin (CaM) binding to the IQ motif in its α subunit. A peptide (Nav1.2IQp, KRKQEEVSAIVIQRAYRRYLLKQKVKK) representing the IQ motif had higher affinity for apo CaM than (Ca2+)4-CaM. Association was mediated solely by the C-domain of CaM. A solution structure (2KXW.pdb) of apo 13C,15N-CaM C-domain bound to Nav1.2IQp was determined with NMR. The region of Nav1.2IQp bound to CaM was helical; R1902, an Nav1.2 residue implicated in familial autism, did not contact CaM. The apo C-domain of CaM in this complex shares features of the same domain bound to myosin V IQ motifs (2IX7) and bound to an SK channel peptide (1G4Y) that does not contain an IQ motif. Thermodynamic and structural studies of CaM-Nav1.2IQp interactions show that apo and (Ca2+)4-CaM adopt distinct conformations that both permit tight association with Nav1.2IQp during gating
Assessing candidate preference through web browsing history
Predicting election outcomes is of considerable interest to candidates, political scientists, and the public at large. We propose the use of Web browsing history as a new indicator of candidate preference among the electorate, one that has potential to overcome a number of the drawbacks of election polls. However, there are a number of challenges that must be overcome to effectively use Web browsing for assessing candidate preferenceâincluding the lack of suitable ground truth data and the heterogeneity of user populations in time and space. We address these challenges, and show that the resulting methods can shed considerable light on the dynamics of votersâ candidate preferences in ways that are difficult to achieve using polls.Accepted manuscrip
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