We propose a model of a firm’s reversible investment decision with macroeconomic conditions based on optimal switching of a diffusion regime. The switching costs and the cash flow generated from the firm depend on a business cycle alternating via a Markov chain, and the triggers of investment and disinvestment in each state are determined endogenously. Provided the investment costs are cyclical...

In the context of semi-abelian categories, several additional conditions have been considered in order to obtain a closer group-like behavior. Among them are locally algebraic cartesian closedness and algebraic coherence. The recent notion of S-protomodular categories, whose main examples are the category of monoids and, more generally, categories of monoids with operations and Jónsson-Tarski v...

A unit-vector field n : P → S2 on a convex polyhedron P ⊂ R3 satisfies tangent boundary conditions if, on each face of P , n takes values tangent to that face. Tangent unit-vector fields are necessarily discontinuous at the vertices of P . We consider fields which are continuous elsewhere. We derive a lower bound E P (h) for the infimum Dirichlet energy Einf P (h) for such tangent unit-vector f...

Sickle hemoglobin (Fe(II)HbS) reconstituted with nickel(II)protoporphyrin IX yields an artificial hemoglobin (Ni(II)HbS), the first heme-substituted hemoglobin shown to mimic the polymerization of deoxyHbS. Unlike Fe(II)HbS, Ni(II)HbS does not bind oxygen and therefore polymerizes under aerobic conditions. While the polymer solubility coefficient (Csat) for Ni(II)HbS is elevated about 2 g/100 m...

Aims: Cystathionine b-synthase (CBS) catalyzes the first and rate-limiting step in the two-step trans-sulfuration pathway that converts homocysteine to cysteine. It is also one of three major enzymes responsible for the biogenesis of H2S, a signaling molecule. We have previously demonstrated that CBS is activated in cells challenged by oxidative stress, but the underlying molecular mechanism of...

A graph G is s-Hamiltonian if for any S ⊆ V (G) of order at most s, G−S has a Hamiltonian-cycle, and s-Hamiltonian connected if for any S ⊆ V (G) of order at most s, G − S is Hamiltonian-connected. Let k > 0, s ≥ 0 be two integers. The following are proved in this paper: (1) Let k ≥ s+ 2 and s ≤ n− 3. If G is a k-connected graph of order n and if max{d(v) : v ∈ I} ≥ (n+s)/2 for every independen...

*Correspondence: [email protected] 1Department of Quantitative Methods for Economics and Business, University of Granada, Granada, Spain Full list of author information is available at the end of the article Abstract Very recently, Roldán-López-de-Hierro and Shahzad introduced the notion of R-contractions as an extension of several notions given by different researchers (for instance, R-contractio...

Motivated by new techniques in the computation of scattering amplitudes of massless particles in four dimensions, like BCFW recursion relations, the question of how much structure of the S-matrix can be determined from purely S-matrix arguments has received new attention. The BCFW recursion relations for massless particles of spin 1 and 2 imply that the whole tree-level S-matrix can be determin...

in this paper the notion of rees short exact sequence for s-posets is introduced, and we investigate the conditions for which these sequences are left or right split. unlike the case for s-acts, being right split does not imply left split. furthermore, we present equivalent conditions of a right s-poset p for the functor hom(p;-) to be exact.