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Macroscopic quantum phase coherence has one of its pivotal expressions in the Josephson effect [1], which manifests itself both in charge [2] and energy transport [3-5]. The ability to master the amount of heat transferred through two tunnel-coupled superconductors by tuning their phase difference is the core of coherent caloritronics [4-6], and is expected to be a key tool in a number of nanoscience fields, including solid state cooling [7], thermal isolation [8, 9], radiation detection [7], quantum information [10, 11] and thermal logic [12]. Here we show the realization of the first balanced Josephson heat modulator [13] designed to offer full control at the nanoscale over the phase-coherent component of thermal currents. Our device provides magnetic-flux-dependent temperature modulations up to 40 mK in amplitude with a maximum of the flux-to-temperature transfer coefficient reaching 200 mK per flux quantum at a bath temperature of 25 mK. Foremost, it demonstrates the exact correspondence in the phase-engineering of charge and heat currents, breaking ground for advanced caloritronic nanodevices such as thermal splitters [14], heat pumps [15] and time-dependent electronic engines [16-19]., Comment: 6+ pages, 4 color figures

En este artículo se hace un análisis crítico de la regulación normativa de las telecomunicaciones tanto antes como después de su apertura, así como del fundamento legal de la potestad de imperio respecto a dichas regulaciones.

We report an experimental study of the scaling of zero-bias conductance peaks compatible with Majorana zero modes as a function of magnetic field, tunnel coupling, and temperature in one-dimensional structures fabricated from an epitaxial semiconductor-superconductor heterostructure. Results are consistent with theory, including a peak conductance that is proportional to tunnel coupling, saturates at $2e^2/h$, decreases as expected with field-dependent gap, and collapses onto a simple scaling function in the dimensionless ratio of temperature and tunnel coupling., Accepted in Physical Review Letters

Two superconductors coupled by a weak link support an equilibrium Josephson electrical current which depends on the phase difference $\varphi$ between the superconducting condensates [1]. Yet, when a temperature gradient is imposed across the junction, the Josephson effect manifests itself through a coherent component of the heat current that flows oppositely to the thermal gradient for $ \varphi, Comment: 10 pages, 9 color figures

We report the realization of an ultra-efficient low-temperature hybrid heat current rectifier, thermal counterpart of the well-known electric diode. Our design is based on a tunnel junction between two different elements: a normal metal and a superconducting island. Electronic heat current asymmetry in the structure arises from large mismatch between the thermal properties of these two. We demonstrate experimentally temperature differences exceeding $60$ mK between the forward and reverse thermal bias configurations. Our device offers a remarkably large heat rectification ratio up to $\sim 140$ and allows its prompt implementation in true solid-state thermal nanocircuits and general-purpose electronic applications requiring energy harvesting or thermal management and isolation at the nanoscale., Comment: 8 pages, 6 color figures

La potestad regulatoria aunque incipiente ha permeado la sociedad costarricense en los últimos años por lo que es importante señalar sus bases constitucionales y su origen, para una mejor comprensión del Derecho Regulatorio. Se comienza por los orígenes y características de la regulación, así como su naturaleza jurídica y potestades de imperio. Además, se establecen las características fundamentales que debe tener toda regulación económica para funcionar eficientemente. Para efectos de Derecho Comparado se hace referencia a otros países como Estados Unidos, Gran Bretaña, Francia, Argentina, Brasil y Chile para comparar el funcionamiento de los entes reguladores en distintos países. The regulatory authority, even though it is meager, has permeated the Costa Rican society in more recent years. That is why it is important to indicate its constitutional basis and its origin for a better understanding of Regulatory Law. This article begins with the origins, characteristics and the legal nature of regulation. Also, it establishes the fundamental characteristics that economic regulation must have to work efficiently. Other countries such as the United States, Great Britain, France, Argentina, Brazil and Chile are also referenced for a comparison of the operation of regulatory systems. UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Sociales::Instituto de Investigaciones Jurídicas (IIJ) UCR::Vicerrectoría de Docencia::Ciencias Sociales::Facultad de Derecho

The emerging field of phase-coherent caloritronics (from the Latin word "calor", i.e., heat) is based on the possibility to control heat currents using the phase difference of the superconducting order parameter. The goal is to design and implement thermal devices able to master energy transfer with a degree of accuracy approaching the one reached for charge transport by contemporary electronic components. This can be obtained by exploiting the macroscopic quantum coherence intrinsic to superconducting condensates, which manifests itself through the Josephson and the proximity effect. Here, we review recent experimental results obtained in the realization of heat interferometers and thermal rectifiers, and discuss a few proposals for exotic non-linear phase-coherent caloritronic devices, such as thermal transistors, solid-state memories, phase-coherent heat splitters, microwave refrigerators, thermal engines and heat valves. Besides being very attractive from the fundamental physics point of view, these systems are expected to have a vast impact on many cryogenic microcircuits requiring energy management, and possibly lay the first stone for the foundation of electronic thermal logic., 11 pages, 6 colour figures

We investigate the thermal transport properties of a temperature-biased Josephson tunnel junction composed of two different superconductors. We show that this simple system can provide a large negative differential thermal conductance (NDTC) with a peak-to-valley ratio of $\sim 3$ in the transmitted electronic heat current. The NDTC is then exploited to outline the caloritronic analogue of the tunnel diode, which can exhibit a modulation of the output temperature as large as 80 mK at a bath temperature of 50 mK. Moreover, this device may work in a regime of thermal hysteresis that can be used to store information as a thermal memory. On the other hand, the NDTC effect offers the opportunity to conceive two different designs of a thermal transistor, which might operate as a thermal switch or as an amplifier/modulator. The latter shows a heat amplification factor $>1$ in a 500-mK-wide working region of the gate temperature. After the successful realization of heat interferometers and thermal diodes, this kind of structures would complete the conversion of the most important electronic devices in their thermal counterparts, breaking ground for coherent caloritronics nanocircuits where heat currents can be manipulated at will., 9 pages, 7 colour figures

In speech and deed, Lincoln's statesmanship manifests the possibility of an honorable, reasonable, and just love of country—that is, a reflective patriotism imbued by a republican love of liberty under God's Providence. In his speeches and writings, Lincoln consistently underscored that love of country must be governed by “reason,” “wisdom,” and “intelligence.” Thus, in his First Inaugural, March 4, 1861, he characteristically appealed to the combined forces of “Intelligence, patriotism, Christianity, and a firm reliance on Him, who has never yet forsaken this favored land.” Lincoln's reflective patriotism was nurtured by his gratitude to the Founders and measured by his fidelity to a national Union dedicated to the universal moral principles of the Declaration under the particular rule of law established by the Constitution. Historically, it was articulated as an alternative to rival forms of allegiance that Lincoln opposed as both unjust and unreasonable during the Civil War era—namely, section...

“Today, turnover rates among DSPs (direct support professionals) in private community residential settings are consistently within the 40%–70% range” (p. xi). This staggering and problematic statis...

We report the realization of a ballistic Josephson interferometer. The interferometer is made by a quantum ring etched in a nanofabricated two-dimensional electron gas confined in an InAs-based heterostructure laterally contacted to superconducting niobium leads. The Josephson current flowing through the structure shows oscillations with h/e flux periodicity when threading the loop with a perpendicular magnetic field. This periodicity, in sharp contrast with the h/2e one observed in conventional dc superconducting quantum interference devices, confirms the ballistic nature of the device in agreement with theoretical predictions. This system paves the way for the implementation of interferometric Josephson pi-junctions, and for the investigation of Majorana fermions., 4+ pages, 4 colored figures

Background: In 1968, De Barsy reported on a girl exhibiting an aged aspect, ‘dwarfism, oligophrenia, and degeneration of the elastic tissue in cornea and skin’. The disorder was recognized as a subgroup of cutis laxa syndrome and termed De Barsy–Moens–Dierckx syndrome. The pathogenesis of the disorder is unknown. Methods: To improve the comprehension of the pathogenetic mechanisms involved in the De Barsy syndrome, we performed an ultrastructural, morphometric, immunocytochemical study on a skin biopsy of a boy with the De Barsy phenotype, who has been clinically followed for 12 years from birth. Moreover, the lysyl oxidase activity was measured on skin fibroblasts cultured in vitro. Results: Light and electron microscopy, morphometry, and immunocytochemical observations showed a significant reduction of the elastic fibers in the papillary and in the reticular dermis of patient compared to an age-matched control (p

Lincoln's Christianity. By Michael Burkhimer. (Yardley, PA: Westholme Publishing. 2007. Pp. xiv, 210. $24.95 paperback. ISBN 978-1-59416-053-0.) Abraham Lincoln memorably invoked the Bible in his public speeches and writings. Yet defining the precise character of his personal religious convictions has proved elusive. His wife, Mary Todd, remarked that "he was a religious man by nature. . . [yet] he was never a technical Christian." The debate over Lincoln's faith began shortly after his death, when his law partner William Herndon announced that he was an "infidel." Was honest Abe dishonest in his use of religious rhetoric to stir the emotions of a Bible-reading nation in support of the Union cause? While important in revealing Lincoln's youthful skepticism and the unorthodox character of his belief, Herndon's account requires qualification. As David Donald has noted, Herndon was driven to overstatement in response to the hagiographie qualities of J. G. Holland's biography, published in 1865, which claimed that Lincoln had made an explicit profession of the Christian faith. Moreover, Herndon's own testimony is itself inconsistent and unclear. For example, in one sentence he characterizes Lincoln as "an infidel ... a Universalist ... a Unitarian .. . aTheist"-"four distinct propositions," as Donald notes.1 The debate over Lincoln's religious beliefs continues today, with each side in the culture war appealing to him in support of its own view of religion's role in American public life. This is not surprising given the centrality of the Sixteenth President to our democratic self-understanding. In general, those of the secular left claim that he was a skeptic, while those of the religious right regard him as an evangelical Christian. Lincoln's Christianity by Michael Burkhimer is therefore highly recommended as a clear and concise work that sheds much light on the elusive topic of the Sixteenth President's religious belief. Burkhimer rejects the simple dichotomy between Lincoln as either a skeptic or an evangelical. This temptation to fit Lincoln neatly into one category or the other has been the source of many interpretative pitfalls. Instead, Burkhimer provides persuasive evidence to support his view that the Sixteenth President's faith developed and deepened over time."Though he was slowly brought into a Christian faith starting in 1849-1850, his last four years saw a blossoming and a deepening spiritually in his life and writings" (p. 107). Burkhimer begins by exploring the religious environment of Lincoln's early youth. The Calvinist teaching of predestination would exert a consistent influence upon Lincoln's belief throughout the rest of his life. …

We report the realization and investigation of a ballistic Andreev interferometer based on an InAs two dimensional electron gas coupled to a superconducting Nb loop. We observe strong magnetic modulations in the voltage drop across the device due to quasiparticle interference within the weak-link. The interferometer exhibits flux noise down to $\sim 80\, \mu\Phi_0/\sqrt{\textrm{Hz}}$, and a robust behavior in temperature with voltage oscillations surviving up to $\sim7\,$K. Besides this remarkable performance, the device represents a crucial first step for the realization of a fully-tunable ballistic superconducting magnetometer and embodies a potential new platform for the investigation of Majorana bound states as well as non-local entanglement of Cooper pairs., Comment: 4+ pages, 4 color figures

Summary We used a rat model to correlate age, matrix gene expression and lysyl oxidase activity in three connective tissues, skin, aorta and lung. By in situ hybridization, we showed that intense collagen type I and elastin mRNA expression were limited to a brief postnatal period. Although there were some organ-specific differences, the mRNA abundance for these two scleroproteins drastically diminished with time. Thus, the majority of mesenchymal cells in young (60days) and old (720 days) animals, appeared to be in a quiescent state, consistent with the slow turnover of these two scleroproteins. We also measured the activity of lysyl oxidase, an enzyme which plays a crucial role in the formation of crosslinks in both pro collagen and tropoelastin molecules. In all the organs investigated, we observed a tissue-dependent pattern of activity. Moreover in this study we focused on the importance of gene matrix expression in evaluating lysyl oxidase activity of aging tissues.

Aponeurotic tissue from seven normal subjects and from apparently unaffected branches, nodules and cords of 16 Dupuytren’s patients were compared. Control tissue was characterized by polymorphous cells, showing cytoplasmic microfilament bundles, numerous pinocytic vesicles, basement membrane-like structures, and a thick coat of interwoven filaments, and by type I- and III-positive heterogeneous collagen fibrils, fibronectin, vitronectin, decorin and proteoglycans. The clinically normal branches consisted of fibroblast-like cells, small type III-highly positive collagen fibrils, fibronectin and proteoglycans. Nodules and fibrotic cords contained fibroblast-like cells, type I and III collagen, fibronectin and proteoglycans. Myofibroblast-like cells in only five out of 16 patients were present. There was no relation between clinical stage and structural alterations; the whole aponeurosis always seemed to be involved; cord retraction would seem to depend on the interactions among fibroblast-like cells and matrix components and among matrix macro-molecules themselves.

Elastin fibres are present in all connective tissues of vertebrates, and are particularly abundant in those undergoing physiological mechanical stress. Elastin, the main component of the fibres, is secreted as soluble tropoelastin molecules, that are crosslinked into insoluble aggregates in the extracellular space. Tropoelastin is highly hydrophobic and is encoded by a single copy gene, localized on chromosome 7 in humans; the primary transcript undergoes alternate splicing giving rise to different tropoelastin molecules, whose distribution and physiological significance are still under investigation. Elastin shows a transient developmental expression, with barely detectable turnover during adult life. In thin sections, elastin fibres appear rather compact and consist of an amorphous material (true elastin) and of longitudinal strips, probably made of various components. By freeze-fracture and negative staining, the elastin fibre has been shown to be made of a loose irregular network of beaded filaments, which can be oriented by stretching. Cytochemical and immunocytochemical approaches have shown that elastin fibres contain proteoglycans as well as sites recognized by antibodies to lysyl oxidase and microfibrillar components. It has been suggested that microfibrils and proteoglycans might have a role in elastin fibrogenesis. Elastin fibres undergo irreversible alterations during aging and in pathological conditions. These alterations consists mainly of accumulation of ions and of abnormal matrix constituents, and/or swelling and disaggregation of the fibre itself.

Connective tissues such as blood vessels are known to be greatly affected by age because of impaired functional properties and increased susceptibility to diseases. With the aim of providing further information on the role of the extracellular matrix in age-related modifications, we investigated the aorta in the rat model from birth to senescence by means of morphological and morphometric observations and by evaluation of lysyl oxidase activity. Results focused on the dramatic vascular rearrangements due to progressive fibrosis of the extracellular matrix and on prominent elastin modifications. The presence of lysyl oxidase activity, even in the oldest animals, might be at least partly responsible for the increased stiffness of the aging extracellular matrix. The striking age-related remodeling of the aortic architecture and the alterations of the interactions between cellular and extracellular compartments might greatly influence the functional properties of the arterial wall in senescence, at least contributing to the consequences of some apparently age-related vascular disorders.