Inorganic carbon physiology underpins macroalgal responses to elevated CO2

Beneficial effects of CO2 on photosynthetic organisms will be a key driver of ecosystem change under ocean acidification. Predicting the responses of macroalgal species to ocean acidification is complex, but we demonstrate that the response of assemblages to elevated CO2 are correlated with inorganic carbon physiology. We assessed abundance patterns and a proxy for CO2:HCO3- use (\u3b413C values) of macroalgae along a gradient of CO2 at a volcanic seep, and examined how shifts in species abundance at other Mediterranean seeps are related to macroalgal inorganic carbon physiology. Five macroalgal species capable of using both HCO3- and CO2 had greater CO2 use as concentrations increased. These species (and one unable to use HCO3-) increased in abundance with elevated CO2 whereas obligate calcifying species, and non-calcareous macroalgae whose CO2 use did not increase consistently with concentration, declined in abundance. Physiological groupings provide a mechanistic understanding that will aid us in determining which species will benefit from ocean acidification and why

Practical guidelines for rigor and reproducibility in preclinical and clinical studies on cardioprotection

The potential for ischemic preconditioning to reduce infarct size was first recognized more than 30 years ago. Despite extension of the concept to ischemic postconditioning and remote ischemic conditioning and literally thousands of experimental studies in various species and models which identified a multitude of signaling steps, so far there is only a single and very recent study, which has unequivocally translated cardioprotection to improved clinical outcome as the primary endpoint in patients. Many potential reasons for this disappointing lack of clinical translation of cardioprotection have been proposed, including lack of rigor and reproducibility in preclinical studies, and poor design and conduct of clinical trials. There is, however, universal agreement that robust preclinical data are a mandatory prerequisite to initiate a meaningful clinical trial. In this context, it is disconcerting that the CAESAR consortium (Consortium for preclinicAl assESsment of cARdioprotective therapies) in a highly standardized multi-center approach of preclinical studies identified only ischemic preconditioning, but not nitrite or sildenafil, when given as adjunct to reperfusion, to reduce infarct size. However, ischemic preconditioning—due to its very nature—can only be used in elective interventions, and not in acute myocardial infarction. Therefore, better strategies to identify robust and reproducible strategies of cardioprotection, which can subsequently be tested in clinical trials must be developed. We refer to the recent guidelines for experimental models of myocardial ischemia and infarction, and aim to provide now practical guidelines to ensure rigor and reproducibility in preclinical and clinical studies on cardioprotection. In line with the above guideline, we define rigor as standardized state-of-the-art design, conduct and reporting of a study, which is then a prerequisite for reproducibility, i.e. replication of results by another laboratory when performing exactly the same experiment

Uniqueness results for nonlinear elliptic equations with a lower order term

We prove the uniqueness of the weak solution of noncoercive nonlinear elliptic problems whose model is u ∈ W_^1,p (Ω), -div(a(x)(1+|∇u|^2)^(p-2)/2 ∇u)+b(x)(1+|∇u|2)(σ+1)/2=f in D′(Ω), where Ω is a bounded open subset of RN, N>2, p satisfies p ≥2N/(N+1), a is a function belonging to L^∞(Ω) such that a(x) ≥α>0, f belongs to the dual space W-1,p′(Ω), b belongs to some Lebesgue space L^r(Ω) with r>r*(N,p) and σ belongs to the interval [0,σ*(N,p,r)], with σ*(N,p,r) and r*(N,p) functions which are specified below

Existence and uniqueness results for nonlinear elliptic problems with a lower order term and measure datum

In this Note we consider a class of noncoercive nonlinear problems whose prototype is -Delta(p)u + b(x)delu(lambda) = mu in Omega, u = 0 on partial derivativeOmega where Q is a bounded open subset of R-N (N greater than or equal to 2), Delta(p) is the so called p-Laplace operator (1 < p < N) or a variant of it, g is a Radon measure with bounded variation on 2 or a function in L-1 (Omega), lambda greater than or equal to 0 and b belongs to the Lorentz space L-N,L-1 (Omega) or to the Lebesgue space L-infinity(Omega). We prove existence and uniqueness of renormalized solutions. To cite this article: M.F. Betta et al., C R. Acad. Sci. Paris, Ser. I 334 (2002) 757-762. (C) 2002 Academie des sciences/Editions scientifiques et medicales Elsevier SAS