Decoherence of Einstein-Podolsky-Rosen steering

We consider two systems A and B that share Einstein-Podolsky-Rosen (EPR) steering correlations and study how these correlations will decay, when each of the systems are independently coupled to a reservoir. EPR steering is a directional form of entanglement, and the measure of steering can change depending on whether the system A is steered by B, or vice versa. First, we examine the decay of the steering correlations of the two-mode squeezed state. We find that if the system B is coupled to a reservoir, then the decoherence of the steering of A by B is particularly marked, to the extent that there is a sudden death of steering after a finite time. We find a different directional effect, if the reservoirs are thermally excited. Second, we study the decoherence of the steering of a Schr\"odinger cat state, modeled as the entangled state of a spin and harmonic oscillator, when the macroscopic system (the cat) is coupled to a reservoir

Carl Djerassi: “In memoriam”. Pionero de la creación del “anticonceptivo oral” y hombre polifacético

ResumenCarl Djerassi nació en Viena en 1923 y emigró a New York en 1939 donde escribió una carta a Eleanor Roosevelt solicitando un apoyo para continuar sus estudios, graduándose en química en 1942 y obteniendo su doctorado en química en la Universidad de Wisconsin en 1945. Sintetizó el esteroide básico del “anticonceptivo oral”, genéricamente conocido como noretisterona. Desde el siglo pasado se sabía que la administración parenteral de estrógenos y progesterona inhibía la ovulación, pero resultaba de un costo muy elevado. Jorge Rosenkranz invitó a Djerassi a incorporarse a Syntex para buscar la síntesis de progesterona, quienes junto con Luis E. Miramontes emplearon el esteroide esencial obtenido del barbasco descubierto por Rusell E. Marker. De esta manera se consiguió industrializar el anticonceptivo hormonal oral conocido trivialmente como la “píldora”.Djerassi se podría considerar como un conspicuo químico, biólogo y sociólogo; incursionó en la literatura, fue coleccionista de arte y benefactor de artistas. Fue presidente de Syntex en México y en Palo Alto. Falleció el 30 de enero de 2015 a la edad de 91 años en San Francisco California.AbstractCarl Djerassi (Vienna, 1923) immigrated to New York in 1939, where he wrote to Eleanor Roosevelt requesting funding to continue his studies, graduating in chemistry in 1942, and acquiring a doctorate in chemistry at the University of Wisconsin in 1945. He synthesised the basic “oral contraceptive” steroid, known generically as norethisterone. Since the preceding century parenteral estrogens and progesterone had been known to inhibit ovulation, but producing them was very expensive. Jorge Rosenkranz invited Djerassi to join Syntex to work on progesterone synthesis; together with Luis E. Miramontes, the researchers used the essential steroid from barbasco [a Mexican yam] discovered by Russell E. Marker to make it possible to industrialise the oral hormonal contraceptive commonly known as “the pill”.Djerassi could be considered as a distinguished chemist, biologist and sociologist, who also pursued literature and was an art collector and artists’ benefactor. Past president of Syntex in Mexico and in Palo Alto, he died on 30 January 2015 at the age of 91 in San Francisco, California

Sex Hormones: Role in Neurodegenerative Diseases and Addiction

The brain is a complex organ in charge of regulating the homeostasis of our body and behaviors such as motivation, reward, memory, and movement control, between others. These behaviors are regulated by dopaminergic neurons, which can be modulated by several stimuli throughout the life of an individual. For example, early exposure to sex hormones or endocrine disruptors during critical period of neuronal development affects dopaminergic pathways permanently, producing some disorders such as drug addiction. On the other hand, current knowledge regarding neurodegeneration in Parkinson and Alzheimer diseases pointed out the neuroprotection that estradiol can exert, but contradictory information can also be found in the literature. To know the underlying mechanisms that are related to the above mentioned diseases will help to improve health policies and treatments development

Hybrid Access Techniques for Densely Populated Wireless Local Area Networks

Postprint (published version

La eficiencia energética a través de los proyectos de cogeneración

El principal objetivo de los proyectos de cogeneración es la eficiencia energética en los sistemas en los que se requiere satisfacer una demanda simultánea de energías en la forma de trabajo mecánico, y de calor. Los paradigmas de inicios de la revolución industrial permitieron la obtención de los correspondientes vectores energéticos separadamente mediante los procesos “monopropósito” o “no integrados”, que se caracterizan por su ineficiencia entálpica en la obtención de trabajo, y exergética en la de vectores calóricos. La obtención simultánea de ambos permite hacerlo en una forma sustancialmente mas eficiente, pero produce rigideces que deben ser analizados y resueltos adecuadamente. Ellos pueden ser de carácter técnico, económico, o de otra índole. En el presente trabajo se tratará el primero de ellos.The main objective of cogeneration projects is the energy efficiency improvement in the systems in those that are required to satisfy a simultaneous demands of energy in the form of mechanical work, and in the form of heat. The paradigms of beginnings of the industrial revolution allowed the obtaining of the corresponding useful energy separately by means of the "heat only” and “power only” or "not integrated" processes. They are characterized by their enthalpic inefficiency in the obtaining of work, and exergetic inefficiency in that of obtaining useful heat. The simultaneous obtaining of both forms of energy allows to make it substantially more efficient, but some rigidities take place that should be analyzed and resolved appropriately. They may be of technical, or economic character, or of another nature. Presently work will deal with the first one.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

La eficiencia energética a través de los proyectos de cogeneración

El principal objetivo de los proyectos de cogeneración es la eficiencia energética en los sistemas en los que se requiere satisfacer una demanda simultánea de energías en la forma de trabajo mecánico, y de calor. Los paradigmas de inicios de la revolución industrial permitieron la obtención de los correspondientes vectores energéticos separadamente mediante los procesos “monopropósito” o “no integrados”, que se caracterizan por su ineficiencia entálpica en la obtención de trabajo, y exergética en la de vectores calóricos. La obtención simultánea de ambos permite hacerlo en una forma sustancialmente mas eficiente, pero produce rigideces que deben ser analizados y resueltos adecuadamente. Ellos pueden ser de carácter técnico, económico, o de otra índole. En el presente trabajo se tratará el primero de ellos.The main objective of cogeneration projects is the energy efficiency improvement in the systems in those that are required to satisfy a simultaneous demands of energy in the form of mechanical work, and in the form of heat. The paradigms of beginnings of the industrial revolution allowed the obtaining of the corresponding useful energy separately by means of the "heat only” and “power only” or "not integrated" processes. They are characterized by their enthalpic inefficiency in the obtaining of work, and exergetic inefficiency in that of obtaining useful heat. The simultaneous obtaining of both forms of energy allows to make it substantially more efficient, but some rigidities take place that should be analyzed and resolved appropriately. They may be of technical, or economic character, or of another nature. Presently work will deal with the first one.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES