Long-term Information, Short-lived Securities

We explore strategic trade in short-lived securities by agents who possess long-term information. Trading short-lived securities is profitable only if enough of the private information becomes public prior to contract expiration; otherwise the security will worthlessly expire. We highlight how this results in trading behavior fundamentally different from that observed in standard models of informed trading in equity. Specifically, we show that informed agents are more reluctant to trade shorter-term securities too far in advance of when their information will necessarily be made public, and that existing positions in a shorter-term security make future purchases more attractive. Because informed agents prefer longer-term securities, this can make trading shorter-term contracts more attractive for liquidity traders. We characterize the conditions under which liquidity traders choose to incur extra costs to roll over short-term positions rather than trade in distant contracts, providing an explanation for why most longer-term derivative security markets have little liquidity and large bid-ask spreads.Priviate information, derivative securities, rolling the hedge, fixed transaction costs

Physiological proteomics of gram-positive bacteria

Comunicaciones a congreso

Sneutrino as Lightest Supersymmetric Particle in B3 mSUGRA Models and Signals at the LHC

We consider B3 mSUGRA models where we have one lepton number violating LQD operator at the GUT scale. This can alter the supersymmetric mass spectrum leading to a sneutrino as the lightest supersymmetric particle in a large region of parameter space. We take into account the restrictions from neutrino masses, the muon anomalous magnetic moment, b -> s gamma and other precision measurements. We furthermore investigate existing restrictions from direct searches at LEP, the Tevatron and the CERN p\bar p collider. We then give examples for characteristic signatures at the LHC.Comment: 22 pages, 11 figure

Sources of variability in essential oil composition of Ocimum americanum and Ocimum tenuiflorum

Basil has traditionally been used for a long time in medicine and gastronomy. Essential oil is the most important active substance of the drug, which influences the aroma and the effect of the plant. Although the compositions of essential oils vary in different basil cultivars, the main components are oxygenated monoterpenes and phenylpropane derivates. The high chemical variation is most likely caused by interspecific hybridization. Various factors, like genetic background, ontogenesis, morphogenesis, abiotic factors, essential oil extraction method, drying, and storage, are responsible for the variant essential oil composition

How to do health services research in stroke: a focus on performance measurement and quality improvement

The objective of this ‘How to’ research series article is to provide guidance on getting started in Health Services Research. The purpose of health services research is to contribute knowledge that can be used to help improve health systems and clinical services through influencing policy and practice. The methods used are broad, have varying levels of rigour and may require different specialist skills. This paper sets out practical steps for undertaking health services research. Importantly, use of the highlighted techniques can identify solutions to address inadequate knowledge translation or promote greater access to evidence-based stroke care to optimise patient outcomes

Impacts of Land Abandonment on Vegetation: Successional Pathways in European Habitats

Changes in traditional agricultural systems in Europe in recent decades have led to widespread abandonment and colonization of various habitats by shrubs and trees. We combined several vegetation databases to test whether patterns of changes in plant diversity after land abandonment in different habitats followed similar pathways. The impacts of land abandonment and subsequent woody colonization on vegetation composition and plant traits were studied in five semi-natural open habitats and two arable habitats in six regions of Europe. For each habitat, vegetation surveys were carried out in different stages of succession using either permanent or non-permanent plots. Consecutive stages of succession were defined on a physiognomic basis from initial open stages to late woody stages. Changes in vegetation composition, species richness, numbers of species on Red Lists, plant strategy types, Ellenberg indicator values of the vegetation, Grime CSR strategy types and seven ecological traits were assessed for each stage of the successional pathway. Abandonment of agro-pastoral land-use and subsequent woody colonization were associated with changes in floristic composition. Plant richness varied according to the different habitats and stages of succession, but semi-natural habitats differed from arable fields in several ecological traits and vegetation responses. Nevertheless, succession occurred along broadly predictable pathways. Vegetation in abandoned arable fields was characterized by a decreasing importance of R-strategists, annuals, seed plants with overwintering green leaves, insect-pollinated plants with hemi-rosette morphology and plants thriving in nutrient-rich conditions, but an increase in species considered as endangered according to the Red Lists. Conversely, changes in plant traits with succession within the initially-open semi-natural habitats showed an increase in plants thriving in nutrient-rich conditions, stress-tolerant plants and plants with sexual and vegetative reproduction, but a sharp decrease in protected species. In conclusion, our study showed a set of similarities in responses of the vegetation in plant traits after land abandonment, but we also highlighted differences between arable fields and semi-natural habitats, emphasizing the importance of land-use legacy

Expression of CD226 is associated to but not required for NK cell education

AbstractDNAX accessory molecule-1 (DNAM-1, also known as CD226) is an activating receptor expressed on subsets of natural killer (NK) and T cells, interacts with its ligands CD155 or CD112, and has co-varied expression with inhibitory receptors. Since inhibitory receptors control NK-cell activation and are necessary for MHC-I-dependent education, we investigated whether DNAM-1 expression is also involved in NK-cell education. Here we show an MHC-I-dependent correlation between DNAM-1 expression and NK-cell education, and an association between DNAM-1 and NKG2A that occurs even in MHC class I deficient mice. DNAM-1 is expressed early during NK-cell development, precedes the expression of MHC-I-specific inhibitory receptors, and is modulated in an education-dependent fashion. Cd226−/− mice have missing self-responses and NK cells with a normal receptor repertoire. We propose a model in which NK-cell education prevents or delays downregulation of DNAM-1. This molecule endows educated NK cells with enhanced effector functions but is dispensable for education.</jats:p

Testing Dividend Signalling Models

This paper derives a key monotonicity property common to all dividend signaling models: the greater the rate that dividend income is taxed relative to capital gains income, the greater the value of information revealed by a given dividend, and hence the greater the associated excess return. This monotonicity condition is tested with robust non-parametric techniques. No evidence is found to support dividend signaling models. The same results are inconsistent with tax-based CAPM arguments

The MarR-Type Repressor MhqR Confers Quinone and Antimicrobial Resistance in Staphylococcus aureus

Aims: Quinone compounds are electron carriers and have antimicrobial and toxic properties due to their mode of actions as electrophiles and oxidants. However, the regulatory mechanism of quinone resistance is less well understood in the pathogen Staphylococcus aureus. Results: Methylhydroquinone (MHQ) caused a thiol-specific oxidative and electrophile stress response in the S. aureus transcriptome as revealed by the induction of the PerR, QsrR, CstR, CtsR, and HrcA regulons. The SACOL2531-29 operon was most strongly upregulated by MHQ and was renamed as mhqRED operon based on its homology to the Bacillus subtilis locus. Here, we characterized the MarR-type regulator MhqR (SACOL2531) as quinone-sensing repressor of the mhqRED operon, which confers quinone and antimicrobial resistance in S. aureus. The mhqRED operon responds specifically to MHQ and less pronounced to pyocyanin and ciprofloxacin, but not to reactive oxygen species (ROS), hypochlorous acid, or aldehydes. The MhqR repressor binds specifically to a 9–9 bp inverted repeat (MhqR operator) upstream of the mhqRED operon and is inactivated by MHQ in vitro, which does not involve a thiol-based mechanism. In phenotypic assays, the mhqR deletion mutant was resistant to MHQ and quinone-like antimicrobial compounds, including pyocyanin, ciprofloxacin, norfloxacin, and rifampicin. In addition, the mhqR mutant was sensitive to sublethal ROS and 24 h post-macrophage infections but acquired an improved survival under lethal ROS stress and after long-term infections. Innovation: Our results provide a link between quinone and antimicrobial resistance via the MhqR regulon of S. aureus. Conclusion: The MhqR regulon was identified as a novel resistance mechanism towards quinone-like antimicrobials and contributes to virulence of S. aureus under long-term infections

Finding Direct-Collapse Black Holes at Birth

Direct-collapse black holes (DCBHs) are currently one of the leading contenders for the origins of the first quasars in the universe, over 300 of which have now been found at $z >$ 6. But the birth of a DCBH in an atomically-cooling halo does not by itself guarantee it will become a quasar by $z \sim$ 7, the halo must also be located in cold accretion flows or later merge with a series of other gas-rich halos capable of fueling the BH's rapid growth. Here, we present near infrared luminosities for DCBHs born in cold accretion flows in which they are destined to grow to 10$^9$ M$_{\odot}$ by $z \sim$ 7. Our observables, which are derived from cosmological simulations with radiation hydrodynamics with Enzo, reveal that DCBHs could be found by the James Webb Space Telescope at $z \lesssim$ 20 and strongly-lensed DCBHs might be found in future wide-field surveys by Euclid and the Wide-Field Infrared Space Telescope at $z \lesssim$ 15.Comment: 5 pages, 2 figures, accepted by ApJ