305 research outputs found
The Effects of Exchange Rates on Export Prices of Farmed Salmon
The CBS inverse demand system is extended to include exchange rates. Applying the extended model to trade data for farmed salmon, results suggest export prices are at least as sensitive to changes in exchange rates as to changes in trade volume. Exchange rate pass-through (absorption into export prices) is complete for the Chilean peso and the British pound, but incomplete for the Norwegian kroner and the US dollar. This suggests producers in Chile and the United Kingdom (UK) are more affected by short-term movements in relative currency values than are producers in Norway and Rest of World (ROW). Model simulations suggest currency realignments, especially the depreciation of the Chilean peso, contributed to the 2003-04 collapse in world salmon prices.Exchange rates, flexibilities, inverse demand system, Demand and Price Analysis, International Relations/Trade, Q13, M30, F10,
Mpemba Effect in Crystallization of Polybutene-1
The Mpemba effect and its inverse can be understood as a result of
nonequilibrium thermodynamics. In polymers, changes of state are generally
non-equilibrium processes. However, the Mpemba effect has been rarely reported
in the crystallization of polymers. In the melt, polybutene-1 (PB-1) has the
lowest critical cooling rate in polyolefins and tends to maintain its original
structure and properties with thermal history. A nascent PB-1 sample was
prepared by using metallocene catalysis at low temperature, and the
crystallization behavior and crystalline structure of the PB-1 were
characterized by DSC and WAXS. Experimentally, a clear Mpemba effect is
observed not only in the crystallization of the nascent PB-1 melt in form II
but also in form I obtained from the nascent PB-1 at low melting temperature.
It is proposed that this is due to the differences in the chain conformational
entropy in the lattice which influence conformational relaxation times. The
entropy and the relaxation time can be predicted using the Adam-Gibbs
equations, whereas non-equilibrium thermodynamics is required to describe the
crystallization with the Mpemba effect
A Monte Carlo Study of the Dynamical-Flucautation Property of the Hadronic System Inside Jets
A study of the dynamical fluctuation property of jets is carried out using
Monte Carlo method. The results suggest that, unlike the average properties of
the hadronic system inside jets, the anisotropy of dynamical fluctuations in
these systems changes abruptly with the variation of the cut parameter \yct.
A transition point exists, where the dynamical fluctuations in the hadronic
system inside jet behave like those in soft hadronic collisions, i.e. being
circular in the transverse plan with repect to dynamical fluctuations. This
finding obtained from Jetset and Herwig Monte Carlo is encouraged to be checked
by experiments.Comment: 8 pages, 3 figure
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A Mechanistic Analysis of Phase Evolution and Hydrogen Storage Behavior in Nanocrystalline Mg(BH4)2 within Reduced Graphene Oxide.
Magnesium borohydride (Mg(BH4)2, abbreviated here MBH) has received tremendous attention as a promising onboard hydrogen storage medium due to its excellent gravimetric and volumetric hydrogen storage capacities. While the polymorphs of MBH-alpha (α), beta (β), and gamma (γ)-have distinct properties, their synthetic homogeneity can be difficult to control, mainly due to their structural complexity and similar thermodynamic properties. Here, we describe an effective approach for obtaining pure polymorphic phases of MBH nanomaterials within a reduced graphene oxide support (abbreviated MBHg) under mild conditions (60-190 °C under mild vacuum, 2 Torr), starting from two distinct samples initially dried under Ar and vacuum. Specifically, we selectively synthesize the thermodynamically stable α phase and metastable β phase from the γ-phase within the temperature range of 150-180 °C. The relevant underlying phase evolution mechanism is elucidated by theoretical thermodynamics and kinetic nucleation modeling. The resulting MBHg composites exhibit structural stability, resistance to oxidation, and partially reversible formation of diverse [BH4]- species during de- and rehydrogenation processes, rendering them intriguing candidates for further optimization toward hydrogen storage applications
Validation of a Multivariate Serum Profile for Epithelial Ovarian Cancer Using a Prospective Multi-Site Collection
In previous studies we described the use of a retrospective collection of ovarian cancer and benign disease samples, in combination with a large set of multiplexed immunoassays and a multivariate pattern recognition algorithm, to develop an 11-biomarker classification profile that is predictive for the presence of epithelial ovarian cancer. In this study, customized, Luminex-based multiplexed immunoassay kits were GMP-manufactured and the classification profile was refined from 11 to 8 biomarkers (CA-125, epidermal growth factor receptor, CA 19-9, C-reactive protein, tenascin C, apolipoprotein AI, apolipoprotein CIII, and myoglobin). The customized kits and the 8-biomarker profile were then validated in a double-blinded manner using prospective samples collected from women scheduled for surgery, with a gynecologic oncologist, for suspicion of having ovarian cancer. The performance observed in model development held in validation, demonstrating 81.1% sensitivity (95% CI 72.6 – 87.9%) for invasive epithelial ovarian cancer and 85.4% specificity (95% CI 81.1 – 88.9%) for benign ovarian conditions. The specificity for normal healthy women was 95.6% (95% CI 83.6 – 99.2%). These results have encouraged us to undertake a second validation study arm, currently in progress, to examine the performance of the 8-biomarker profile on the population of women not under the surgical care of a gynecologic oncologist
Foreign language learning as potential treatment for mild cognitive impairment
As the number of older adults increases, age-related health issues (both physical and cognitive) and associated costs are expected to increase, placing emotional and financial stress on family members and the health system. Dementia is one of the most devastating and costly diseases that older adults face. The present study aimed to determine whether foreign language learning can improve cognitive outcomes of older adults with mild cognitive impairment (MCI). The objectives are to determine whether foreign language learning is (1) effective in boosting cognitive reserve and promoting healthy cognitive function and (2) superior to other established cognitively stimulating activities such as crossword and logic puzzles
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Diabetes reversal by inhibition of the low-molecular-weight tyrosine phosphatase.
Obesity-associated insulin resistance plays a central role in type 2 diabetes. As such, tyrosine phosphatases that dephosphorylate the insulin receptor (IR) are potential therapeutic targets. The low-molecular-weight protein tyrosine phosphatase (LMPTP) is a proposed IR phosphatase, yet its role in insulin signaling in vivo has not been defined. Here we show that global and liver-specific LMPTP deletion protects mice from high-fat diet-induced diabetes without affecting body weight. To examine the role of the catalytic activity of LMPTP, we developed a small-molecule inhibitor with a novel uncompetitive mechanism, a unique binding site at the opening of the catalytic pocket, and an exquisite selectivity over other phosphatases. This inhibitor is orally bioavailable, and it increases liver IR phosphorylation in vivo and reverses high-fat diet-induced diabetes. Our findings suggest that LMPTP is a key promoter of insulin resistance and that LMPTP inhibitors would be beneficial for treating type 2 diabetes
Pentraxins and Fc Receptor-Mediated Immune Responses
C-reactive protein (CRP) is a member of the pentraxin family of proteins. These proteins are highly conserved over the course of evolution being present as far back as 250 million years ago. Mammalian pentraxins are characterized by the presence of five identical non-covalently linked subunits. Each subunit has a structurally conserved site for calcium-dependent ligand binding. The biological activities of the pentraxins established over many years include the ability to mediate opsonization for phagocytosis and complement activation. Pentraxins have an important role in protection from infection from pathogenic bacteria, and regulation of the inflammatory response. It was recognized early on that some of these functions are mediated by activation of the classical complement pathway through C1q. However, experimental evidence suggested that cellular receptors for pentraxins also play a role in phagocytosis. More recent experimental evidence indicates a direct link between pentraxins and Fc receptors. The Fc receptors were first identified as the major receptors for immunoglobulins. The avidity of the interaction between IgG complexes and Fc receptors is greatly enhanced when multivalent ligands interact with the IgG binding sites and activation of signaling pathways requires Fc receptor crosslinking. Human pentraxins bind and activate human and mouse IgG receptors, FcγRI and FcγRII, and the human IgA receptor, FcαRI. The affinities of the interactions between Fc receptors and pentraxins in solution and on cell surfaces are similar to antibody binding to low affinity Fc receptors. Crystallographic and mutagenesis studies have defined the structural features of these interactions and determined the stoichiometry of binding as one-to-one. Pentraxin aggregation or binding to multivalent ligands increases the avidity of binding and results in activation of these receptors for phagocytosis and cytokine synthesis. This review will discuss the structural and functional characteristics of pentraxin Fc receptor interactions and their implications for host defense and inflammation
Boost Invariance and Multiplicity Dependence of the Charge Balance Functionin and Collisions at GeV/c
Boost invariance and multiplicity dependence of the charge balance function
are studied in \pi^{+}\rp and \rK^{+}\rp collisions at 250 GeV/ incident
beam momentum. Charge balance, as well as charge fluctuations, are found to be
boost invariant over the whole rapidity region, but both depend on the size of
the rapidity window. It is also found that the balance function becomes
narrower with increasing multiplicity, consistent with the narrowing of the
balance function when centrality and/or system size increase, as observed in
current relativistic heavy ion experiments.Comment: 4 pages, 5 figures, Revte
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