The Angiotensin Affair: How Great Minds Thinking Alike Came to a Historical Agreement

In 1934, J. C. Fasciolo had to submit a thesis and Dr. Houssay suggested he investigate about nephrogenic hypertension. E. Braun‐Menéndez showed interest in helping and Drs. L.F. Leloir and J.M. Muñoz from the Institute of Physiology joined them in their attempt to isolate and purify the pressor substance. In 1939, they extracted the substance “hypertension” from the venous blood from the ischemic kidneys. They proposed an enzyme‐substrate reaction. They named hypertensinogen the substrate and hypertensinases the enzymes that break down the hypertension. Two months following the Argentine publication, the team in the United States, formed by I.H. Page and O.M. Helmer, published their findings, which were in agreement with those reported by the Argentine team. By 1940, they isolated angiotonin, the equivalent of hypertension, and called the renin substrate hypertensinogen. In 1957, in the conference held in Ann Arbor, Braun‐Menéndez and Page agreed on a new nomenclature. As a result, the words angiotensinogen and angiotensin were born from the combination of the names originally set by both teams. The discovery of the renin‐angiotensin system is an example that science should follow: Value the progress made by colleagues, collaborate side by side, and pursue the ultimate truth

Linear-nonlinear duality for circuit design on quantum computing platforms

The unitary description of beam splitters (BSs) and optical parametric amplifiers (OPAs) in terms of the dynamical Lie groups $SU(2)$ and $SU(1,1)$ has a long history. Recently, an inherent duality has been proposed that relates the unitaries of both optical devices. At the physical level, this duality relates the linear nature of a lossless BS to the nonlinear Parametric Down-Conversion (PDC) process exhibited by an OPA. Here, we argue that the duality between BS and PDC can instead be naturally interpreted by analyzing the geometrical properties of both Lie groups, an approach that explicitly connects the dynamical group description of the optical devices with the aforementioned duality. Furthermore, we show that the BS-PDC duality can be represented through tensor network diagrams, enabling the implementation of a PDC as a circuit on a standard quantum computing platform. Thus, it is feasible to simulate nonlinear processes by using single-qubit unitaries that can be implemented on currently available digital quantum processors

Generalized coherence vector applied to coherence transformations and quantifiers

One of the main problems in any quantum resource theory is the characterization of the conversions between resources by means of the free operations of the theory. In this work, we advance on this characterization within the quantum coherence resource theory by introducing the generalized coherence vector of an arbitrary quantum state. The generalized coherence vector is a probability vector that can be interpreted as a concave roof extension of the pure states coherence vector. We show that it completely characterizes the notions of being incoherent, as well as being maximally coherent. Moreover, using this notion and the majorization relation, we obtain a necessary condition for the conversion of general quantum states by means of incoherent operations. These results generalize the necessary conditions of conversions for pure states given in the literature, and show that the tools of the majorization lattice are useful also in the general case. Finally, we introduce a family of coherence quantifiers by considering concave and symmetric functions applied to the generalized coherence vector. We compare this proposal with the convex roof measure of coherence and others quantifiers given in the literature.Comment: 21 pages, 2 figures (close to the published version

Casimir forces from a loop integral formulation

We reformulate the Casimir force in the presence of a non-trivial background. The force may be written in terms of loop variables, the loop being a curve around the scattering sites. A natural path ordering of exponentials take place when a particular representation of the scattering centres is given. The basic object to be evaluated is a reduced (or abbreviated) classical pseudo-action that can be operator valued.Comment: references added, text clarified in place

Silvopastoral Systems: Analyses of an Alternative to Open Swards

Silvopasture is a sustainable land use management practiced in most continents in the world including parts of southern Europe, but is not broadly used in northern and western Europe. The importance of this practice has been recognised and the last draft of the EU regulation by the European Agricultural Fund for Rural Development (http://europa.eu.int/comm/agriculture/capreform/rurdevprop_en.pdf) includes specifically funding for establishment of agroforestry practices in Europe. This paper discusses the advantages of managing semi intensive grassland within a silvopastoral system from an ecological, productive and social point of view in the south, south-central and western countries of Europe