3,547 research outputs found
Hypothesis: âVasocrineâ signalling from perivascular fat - a mechanism linking insulin resistance and vascular disease
Adipose tissue expresses cytokines which inhibit insulin signalling pathways in liver and muscle. Obesity also results in impairment of endothelium-dependent vasodilatation to insulin. We propose a vasoregulatory role for local deposits of fat around the origin of arterioles supplying skeletal muscle. Isolated first order arterioles from rat cremaster muscle are under dual regulation by insulin, which activates both endothelin-1 mediated vasoconstriction and nitric oxide mediated vasodilatation. In obese rat arterioles, insulin-stimulated nitric oxide synthesis is impaired, resulting in unopposed vasoconstriction. We propose this to be the consequence of production of the adipocytokine tumour necrosis factor-α from the cuff of fat seen surrounding the origin of the arteriole in obese rats â a depot to which we ascribe a specialist vasoregulatory role. We suggest that this cytokine accesses the nutritive vascular tree to inhibit insulin-mediated capillary recruitment â a mechanism we term âvasocrineâ signalling. We also suggest a homology between this vasoactive periarteriolar fat and both periarterial and visceral fat, which may explain relationships between visceral fat, insulin resistance and vascular disease
Factor Price Equalization in Heckscher-Ohlin Model
This paper investigates the likelihood of factor-price equalization under the simple assumptions of Heckscher-Ohlin Theory. Factor-price equalization is also directly related to whether countries specialize or not in the global market. A full-equilibrium in the world requires not only the equilibrium in the production side of the economy, but also the supply-demand equality in the world. However, once we obtain an equilibrium in the production side of the economy, it is always possible to define demand in a way to get supply-demand equality at any production side equilibrium amounts. Therefore, it is not possible to talk about factor-price equalization without specifying demand in the economy. Using L-P diagrams, the paper demonstrates how both factor-price equalization and non-equalization cases are possible when we look at only the production side of the economy. It is also demonstrated that the equilibrium possibilities will be much larger for factor-price equalization case if the number of commodities is more than the number of factors of production. However, the larger possibilities do not refer to different real equilibria, but only to indeterminacy in production. When demand is introduced in the economy and supply-demand equality constraints are respected, we see that factor-prices might or might not be equalized depending on factor endowments, production functions and demand. The paper demonstrates this by introducing a model with 2 countries, 2 factors of production, 3 goods and CES utility function. Finally, using comparative statistics on this simple model, the conditions under which the likelihood of factor-price equalization increases are determined.
Connecting qualitative research on exercise and environment to public health agendas requires an equity lens
In this commentary, I respond to the special section in Health & Place (vol. 46) on âExercise and environment: new qualitative work to link popular practice and public healthâ edited by Hitchings and Latham. I argue that if qualitative research is to effectively inform public health policy and practice it cannot ignore the fact that physical activity participation is inequitable. Without building in a critical equity lens, geographers risk perpetuating the âinequality paradoxââthat is, the potential for population health interventions to inadvertently exacerbate health inequalities. Related to this, I challenge the editorsâ assumption that geographersâ critiques of public health approaches to physical activity and our applied efforts to foster physical activity participation are mutually exclusive endeavours. Rather, I argue they are mutually necessary within a social justice agenda. Finally, I close this commentary by offering ways forward for qualitative research on exercise and environment to connect with public health agendas and inform interventions
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Error Terms for the Trapezoid, Midpoint, and Simpson\u27s Rules
When it is not possible to integrate a function we resort to Numerical Integration. For example the ubiquitous Normal curve tables are obtained using Numerical Integration. The antiderivative of the defining function for the normal curve involves the formula for antiderivative of e-x^2 which can\u27t be expressed in the terms of basic functions.
Simpson\u27s rule is studied in most Calculus books, and in all undergraduate Numerical Analysis books, but proofs are not provided. Hence if one is interested in a proof of Simpson\u27s rule, either it can be found in advanced Numerical Analysis books as a special case of the so called Newton-Cotes formulas, or in math journals such as American Mathematical Monthly. My thesis adviser Hajrudin Fejzic, has recently published yet another proof. In this thesis I plan to introduce Numerical Integration formulas such as simpler Composite and Midpoint rules as well as Simpson\u27s rule and I will provide the proofs to these rules using the ideas developed in Dr. Fejzic\u27s publication as well as new proofs based on ideas of Dr. Fejzic that were communicated to me
Etude des couches de passage Couvinien-Givetien entre la vallée de l'Ourthe et la vallée de l'Aisne
This paper deals mainly with the sections in the Aisne Valley, at Rouge-MiniĂšre and Sy. A small section at Filot completes that of Sy. Certain observation could also be made in the Pont-le-PrĂȘtre stream section, near Villers-Sainte-Gertrude and at FerriĂšres. These sections have allowed a better appreciation of the important variations in facies which occur near the Couvinian-Givetian boundary. This boundary has been delimited more exactly on the basis of ostracods, conodonts and corals
Quantum theory of the low-frequency linear susceptibility of interferometer-type superconducting qubits
We use the density matrix formalism to analyze the interaction of
interferometer-type superconducting qubits with a high quality tank circuit,
which frequency is well below the gap frequency of a qubit. We start with the
ground state characterization of the superconducting flux and charge qubits.
Then, by making use of a dressed state approach we describe the qubits'
spectroscopy when the qubit is irradiated by a microwave field which is tuned
to the gap frequency. The last section of the paper is devoted to continuous
monitoring of qubit states by using a DC SQUID in the inductive mode.Comment: 11 pages, 5 figures; the title and abstract are slightly changed;
several typos are corrected; in order to make our argumentation more clear we
added some comments in the introduction and other section
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