5,234 research outputs found
Modeling the Dynamics of Inflation Compensation
This paper investigates the relationship between short-term and
long-term ination expectations using daily data on ination compen-
sation. We use a exible econometric model which allows us to uncover
this relationship in a data-based manner. We relate our
ndings to
the issue of whether ination expectations are anchored, unmoored
or contained. Our empirical results indicate no support for either
unmoored or
rmly anchored ination expectations. Most evidence
indicates that ination expectations are contained.
Quantum to Classical Transition of the Charge Relaxation Resistance of a Mesoscopic Capacitor
We present an analysis of the effect of dephasing on the single channel
charge relaxation resistance of a mesoscopic capacitor in the linear low
frequency regime. The capacitor consists of a cavity which is via a quantum
point contact connected to an electron reservoir and Coulomb coupled to a gate.
The capacitor is in a perpendicular high magnetic field such that only one
(spin polarized) edge state is (partially) transmitted through the contact. In
the coherent limit the charge relaxation resistance for a single channel
contact is independent of the transmission probability of the contact and given
by half a resistance quantum. The loss of coherence in the conductor is modeled
by attaching to it a fictitious probe, which draws no net current. In the
incoherent limit one could expect a charge relaxation resistance that is
inversely proportional to the transmission probability of the quantum point
contact. However, such a two terminal result requires that scattering is
between two electron reservoirs which provide full inelastic relaxation. We
find that dephasing of a single edge state in the cavity is not sufficient to
generate an interface resistance. As a consequence the charge relaxation
resistance is given by the sum of one constant interface resistance and the
(original) Landauer resistance. The same result is obtained in the high
temperature regime due to energy averaging over many occupied states in the
cavity. Only for a large number of open dephasing channels, describing
spatially homogenous dephasing in the cavity, do we recover the two terminal
resistance, which is inversely proportional to the transmission probability of
the QPC. We compare different dephasing models and discuss the relation of our
results to a recent experiment.Comment: 10 pages, 8 figure
Mesoscopic Capacitance Oscillations
We examine oscillations as a function of Fermi energy in the capacitance of a
mesoscopic cavity connected via a single quantum channel to a metallic contact
and capacitively coupled to a back gate. The oscillations depend on the
distribution of single levels in the cavity, the interaction strength and the
transmission probability through the quantum channel. We use a Hartree-Fock
approach to exclude self-interaction. The sample specific capacitance
oscillations are in marked contrast to the charge relaxation resistance, which
together with the capacitance defines the RC-time, and which for spin polarized
electrons is quantized at half a resistance quantum. Both the capacitance
oscillations and the quantized charge relaxation resistance are seen in a
strikingly clear manner in a recent experiment.Comment: 9 pages, 2 figure
Probing the Superfluid to Mott Insulator Transition at the Single Atom Level
Quantum gases in optical lattices offer an opportunity to experimentally
realize and explore condensed matter models in a clean, tunable system. We
investigate the Bose-Hubbard model on a microscopic level using single
atom-single lattice site imaging; our technique enables space- and
time-resolved characterization of the number statistics across the
superfluid-Mott insulator quantum phase transition. Site-resolved probing of
fluctuations provides us with a sensitive local thermometer, allows us to
identify microscopic heterostructures of low entropy Mott domains, and enables
us to measure local quantum dynamics, revealing surprisingly fast transition
timescales. Our results may serve as a benchmark for theoretical studies of
quantum dynamics, and may guide the engineering of low entropy phases in a
lattice
SYNTHESIZING AND INTEGRATING RESEARCH ON IT-BASED VALUE CO-CREATION: A META-ANALYSIS
Recently, competition has shifted from the firm to the network level. Following this path, a growing stream in IT value research has emerged, aiming to understand how multiple firms create value through joint IT resources and capabilities. Despite the efforts made thus far, there are inconsistencies regarding construct definitions and divergent empirical findings. In this paper, we synthesize and integrate the body of knowledge on IT-based value co-creation. Drawing on the relational view, we first synthesize the existing empirical findings. The results of a meta-analysis of 72 studies encompassing 33,732 observations underline the importance of four sources of IT value: IT-based inter-organizational assets, IT-based knowledge sharing, IT-based complementary capabilities, and IT-based governance. A further moderator meta-analysis integrates divergent empirical findings in the literature. We find that objective measures dampen the relationship between inter-organizational IT and business value, while process-level measures and IT capabilities strengthen it. Moreover, we find evidence for higher value impacts in developing countries and an influence of inter-organizational relationship types. This study contributes by clarifying the IT-business value relationship and offers insights into sources of inconsistencies in IT-based value co-creation studies. By doing so, this paper lays a foundation for future research and theory development
Synthesizing and Integrating Research on IT-Based Value Cocreation: A Meta-Analysis
IT value research has witnessed growing interest in the use of joint IT resources and capabilities following recent shifts in market competition from the firm to the network level. Despite research efforts in this domain, there remain substantial inconsistencies in the IT value cocreation literature regarding the effect of interorganizational IT on business value and the role of methodological and contextual factors. Drawing on the resource-based view and the relational view of the firm, we conducted a meta-analysis to synthesize and integrate the body of knowledge of IT-based value cocreation. Our analysis of 80 studies, encompassing 21,843 observations, highlights the value-generating effect of four interorganizational IT capabilities: IT-based relation-specific assets, IT-based knowledge sharing, IT-based complementary capabilities, and IT-based governance. Insights from our preliminary meta-analysis reveal that contradictory findings are driven by the conceptualization of IT variables as interorganizational IT resources. A further moderator meta-analysis explains divergent empirical findings in the literature. We find that the use of relational-level value and perceptual measures, use of single respondents, and the context of developing countries and supply chain and networked interdependencies result in larger estimates of business value. In contrast, the use of network-level, firm-level, and objective measures; use of matched-pair approaches; and the context of developed countries and pooled interdependencies result in smaller estimates. Overall, this paper provides clarity and structure to the current understanding of the research field by providing explanations for inconsistent findings as well as a foundation for future research and theory development
Mode of Inoculation of the Lyme Disease Agent Borrelia burgdorferi Influences Infection and Immune Responses in Inbred Strains of Mice
Mice were infected with Borrelia burgdorferi by infection via Ixodes ricinus and experimental inoculation to determine whether transmission rates of spirochetes and antibody responses are influenced. Mice infected by the natural route were substantially more infective for ticks; two- to sixfold more tick larvae were positive for B. burgdorferi than those fed on experimentally inoculated mice. In natural infection, spirochetemia may be greater or spirochetes may be more accessible for transmission. Thus, this form of xenodiagnosis could be used to determine levels of spirochetes in the vertebrate host. Similar levels of antibody were present in all mice; however, those infected by the natural route lacked antibodies to outer surface proteins (Osp) A and B. The small antigen dose given through a tick bite may not have been sufficient to induce rapid OspA or OspB antibodies, thereby allowing the later development of higher levels of spirochetemi
PI3K/AKT, MAPK and AMPK signalling: protein kinases in glucose homeostasis
New therapeutic approaches to counter the increasing prevalence of obesity and type 2 diabetes mellitus are in high demand. Deregulation of the phosphoinositide-3-kinase (PI3K)/v-akt murine thymoma viral oncogene homologue (AKT), mitogen-activated protein kinase (MAPK) and AMP-activated protein kinase (AMPK) pathways, which are essential for glucose homeostasis, often results in obesity and diabetes. Thus, these pathways should be attractive therapeutic targets. However, with the exception of metformin, which is considered to function mainly by activating AMPK, no treatment for the metabolic syndrome based on targeting protein kinases has yet been developed. By contrast, therapies based on the inhibition of the PI3K/AKT and MAPK pathways are already successful in the treatment of diverse cancer types and inflammatory diseases. This contradiction prompted us to review the signal transduction mechanisms of PI3K/AKT, MAPK and AMPK and their roles in glucose homeostasis, and we also discuss current clinical implication
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