738 research outputs found
Ricardian or Monopoly Rents? The Perspective of Potential Entrants
Tests of the efficiency and market power hypotheses have focused on incumbents’ profitability. The current study examines the issue from the perspective of potential entrants. A key premise of the paper, which follows from the efficiency hypothesis, is that incumbents’ Ricardian rents (resulting from efficiency) usually do not induce entry. However, incumbents’ monopoly rents should attract entry, ceteris paribus. The entry response to adjusted and unadjusted profitability measures is compared. The difference between the measures represents Ricardian rents, according to the efficiency hypothesis, and monopoly rents, according to the market power hypothesis. The results, generally, favor the market power hypothesis.
A Diffusion-Based Approach to Geminate Recombination of Heme Proteins with Small Ligands
A model of postphotodissociative monomolecular (geminate) recombination of
heme proteins with small ligands (NO, O2 or CO) is represented. The
non-exponential decay with time for the probability to find a heme in unbound
state is interpreted in terms of diffusion-like migration of ligabs
physics/0212040 and between protein cavities. The temporal behavior for the
probability is obtained from numerical simulation and specified by two
parameters: the time \tau_{reb} of heme-ligand rebinding for the ligand
localized inside the heme pocket and the time \tau_{esc} of ligand escape from
the pocket. The model is applied in the analysis of available experimental data
for geminate reoxygenation of human hemoglobin HbA. Our simulation is in good
agreement with the measurements. The analysis shows that the variation in pH of
the solution (6.0<pH<9.4) results in considerable changes for \tau_{reb} from
0.36 ns (at pH=8.5) up to 0.5 ns (pH=6.0) but effects slightly on the time
\tau_{esc} (\tau_{esc} ~ 0.88 ns).Comment: 8 pages with 4 figures, submitted to Chem. Phy
COVID Down Under: where did Australia's pandemic apps go wrong?
Governments and businesses worldwide deployed a variety of technological
measures to help prevent and track the spread of COVID-19. In Australia, these
applications contained usability, accessibility, and security flaws that
hindered their effectiveness and adoption. Australia, like most countries, has
transitioned to treating COVID as endemic. However it is yet to absorb lessons
from the technological issues with its approach to the pandemic. In this short
paper we provide a systematization of the most notable events; identify and
review different failure modes of these applications; and develop
recommendations for developing apps in the face of future crises. Our work
focuses on a single country. However, Australia's issues are particularly
instructive as they highlight surprisingly pitfalls that countries should
address in the face of a future pandemic
Dopamine receptor D5 signaling plays a dual role in experimental autoimmune encephalomyelitis potentiating Th17-mediated immunity and favoring suppressive activity of regulatory T-cells
Indexación: Scopus.This work was supported by grants FONDECYT-1170093 (to RP) and FONDECYT-3160383 (to CP) from ‘‘Fondo Nacional de Desarrollo Científico y Tecnológico de Chile’’, AFB170004 (to RP) from ‘‘Comisión Nacional de Investigación Científica y Tecnológica de Chile (CONICYT)’’ and DI-1224-16/R (to RP) from Universidad Andres Bello.A number of studies have shown pharmacologic evidence indicating that stimulation of type I dopamine receptor (DR), favors T-helper-17 (Th17)-mediated immunity involved in experimental autoimmune encephalomyelitis (EAE) and in some other inflammatory disorders. Nevertheless, the lack of drugs that might discriminate between DRD1 and DRD5 has made the pharmacological distinction between the two receptors difficult. We have previously shown genetic evidence demonstrating a relevant role of DRD5-signaling in dendritic cells (DCs) favoring the CD4+ T-cell-driven inflammation in EAE. However, the role of DRD5-signaling confined to CD4+ T-cells in the development of EAE is still unknown. Here, we analyzed the functional role of DRD5-signaling in CD4+ T-cell-mediated responses and its relevance in EAE by using a genetic approach. Our results show that DRD5-signaling confined to naive CD4+ T-cells exerts a pro-inflammatory effect promoting the development of EAE with a stronger disease severity. This pro-inflammatory effect observed for DRD5-signaling in naive CD4+ T-cells was related with an exacerbated proliferation in response to T-cell activation and to an increased ability to differentiate toward the Th17 inflammatory phenotype. On the other hand, quite unexpected, our results show that DRD5-signaling confined to Tregs strengthens their suppressive activity, thereby dampening the development of EAE manifestation. This anti-inflammatory effect of DRD5-signaling in Tregs was associated with a selective increase in the expression of glucocorticoid-induced tumor necrosis factor receptor-related protein (GITR), which has been described to play a critical role in the expansion of Tregs. Our findings here indicate a complex role for DRD5-signaling in CD4+ T-cells-driven responses potentiating early inflammation mediated by effector T-cells in EAE, but exacerbating suppressive activity in Tregs and thereby dampening disease manifestation in late EAE stages. © 2018 Osorio-Barrios, Prado, Contreras and Pacheco.https://www.frontiersin.org/articles/10.3389/fncel.2018.00192/ful
Transactional Scripts in Contract Stacks
Deals accomplished through software persistently residing on computer networks—sometimes called smart contracts, but better termed transactional scripts—embody a potentially revolutionary contracting innovation. Ours is the first precise account in the legal literature of how such scripts are created, and when they produce errors of legal significance.Scripts’ most celebrated use case is for transactions operating exclusively on public, permissionless, blockchains: such exchanges eliminate the need for trusted intermediaries and seem to permit parties to commit ex ante to automated performance. But public transactional scripts are costly both to develop and execute, with significant fees imposed for data storage. Worse, bugs practically can’t be eliminated. The result is that many scripts will terminate in misunderstanding, frustrated intent and failure.When code misdelivers, disappointed parties will seek legal recourse. We argue that jurists should situate scripts within other legally operative statements and disclosures, or contract stacks. Precision about the relationship between script and stack sustains a novel framework, rooted in old doctrines of interpretation, parol evidence and equity, that will help jurists compile answers to the private law problems that digitized exchange entails
Formation of the New England oroclines: insights from Permian sedimentary basins in Eastern Australia
Role of the Subunits Interactions in the Conformational Transitions in Adult Human Hemoglobin: an Explicit Solvent Molecular Dynamics Study
Hemoglobin exhibits allosteric structural changes upon ligand binding due to
the dynamic interactions between the ligand binding sites, the amino acids
residues and some other solutes present under physiological conditions. In the
present study, the dynamical and quaternary structural changes occurring in two
unligated (deoxy-) T structures, and two fully ligated (oxy-) R, R2 structures
of adult human hemoglobin were investigated with molecular dynamics. It is
shown that, in the sub-microsecond time scale, there is no marked difference in
the global dynamics of the amino acids residues in both the oxy- and the deoxy-
forms of the individual structures. In addition, the R, R2 are relatively
stable and do not present quaternary conformational changes within the time
scale of our simulations while the T structure is dynamically more flexible and
exhibited the T\rightarrow R quaternary conformational transition, which is
propagated by the relative rotation of the residues at the {\alpha}1{\beta}2
and {\alpha}2{\beta}1 interface.Comment: Reprinted (adapted) with permission from J. Phys. Chem. B
DOI:10.1021/jp3022908. Copyright (2012) American Chemical Societ
Detecting Excessive Data Exposures in Web Server Responses with Metamorphic Fuzzing
APIs often transmit far more data to client applications than they need, and
in the context of web applications, often do so over public channels. This
issue, termed Excessive Data Exposure (EDE), was OWASP's third most significant
API vulnerability of 2019. However, there are few automated tools -- either in
research or industry -- to effectively find and remediate such issues. This is
unsurprising as the problem lacks an explicit test oracle: the vulnerability
does not manifest through explicit abnormal behaviours (e.g., program crashes
or memory access violations).
In this work, we develop a metamorphic relation to tackle that challenge and
build the first fuzzing tool -- that we call EDEFuzz -- to systematically
detect EDEs. EDEFuzz can significantly reduce false negatives that occur during
manual inspection and ad-hoc text-matching techniques, the current most-used
approaches.
We tested EDEFuzz against the sixty-nine applicable targets from the Alexa
Top-200 and found 33,365 potential leaks -- illustrating our tool's broad
applicability and scalability. In a more-tightly controlled experiment of eight
popular websites in Australia, EDEFuzz achieved a high true positive rate of
98.65% with minimal configuration, illustrating our tool's accuracy and
efficiency
Coin-Operated Capitalism
This Article presents the legal literature’s first detailed analysis of the inner workings of Initial Coin Offerings. We characterize the ICO as an example of financial innovation, placing it in kinship with venture capital contracting, asset securitization, and (obviously) the IPO. We also take the form seriously as an example of technological innovation, where promoters are beginning to effectuate their promises to investors through computer code, rather than traditional contract. To understand the dynamics of this shift, we first collect contracts, “white papers,” and other contract-like documents for the fifty top-grossing ICOs of 2017. We then analyze how such projects’ software code reflected (or failed to reflect) their contractual promises. Our inquiry reveals that many ICOs failed even to promise that they would protect investors against insider self-dealing. Fewer still manifested such contracts in code. Surprisingly, in a community known for espousing a technolibertarian belief in the power of “trustless trust” built with carefully designed code, a significant fraction of issuers retained centralized control through previously undisclosed code permitting modification of the entities’ governing structures. These findings offer valuable lessons to legal scholars, economists, and policymakers about the roles played by gatekeepers; about the value of regulation; and the possibilities for socially valuable private ordering in a relatively anonymous, decentralized environment
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