Effi cient Specialization in Ricardian Production

It is well known that the analysis of efficient specialization in Ricardian production with many countries and many commodities cannot be broken down to the simple case of two countries and two commodities. By drawing on some recent results of convex geometry and the theory of cephoids, this paper characterizes efficient patterns of incomplete specialization in the general case.Ricardian trade; efficient specialization; comparative cost; cephoids; deGua simplexes

“It Don’t Mean a Thing if It Ain’t Got that Swing”– an Alternative Concept for Understanding the Evolution of Dance and Music in Human Beings

The functions of dance and music in human evolution are a mystery. Current research on the evolution of music has mainly focused on its melodic attribute which would have evolved alongside (proto-)language. Instead, we propose an alternative conceptual framework which focuses on the co-evolution of rhythm and dance (R&D;) as intertwined aspects of a multimodal phenomenon characterized by the unity of action and perception. Reviewing the current literature from this viewpoint we propose the hypothesis that R&D; have co-evolved long before other musical attributes and (proto-)language. Our view is supported by increasing experimental evidence particularly in infants and children: beat is perceived and anticipated already by newborns and rhythm perception depends on body movement. Infants and toddlers spontaneously move to a rhythm irrespective of their cultural background. The impulse to dance may have been prepared by the susceptibility of infants to be soothed by rocking. Conceivable evolutionary functions of R&D; include sexual attraction and transmission of mating signals. Social functions include bonding, synchronization of many individuals, appeasement of hostile individuals, and pre- and extra-verbal communication enabling embodied individual and collective memorizing. In many cultures R&D; are used for entering trance, a base for shamanism and early religions. Individual benefits of R&D; include improvement of body coordination, as well as painkilling, anti-depressive, and anti-boredom effects. Rhythm most likely paved the way for human speech as supported by studies confirming the overlaps between cognitive and neural resources recruited for language and rhythm. In addition, dance encompasses visual and gestural communication. In future studies attention should be paid to which attribute of music is focused on and that the close mutual relation between R&D; is taken into account. The possible evolutionary functions of dance deserve more attention

Concentration of Vacancies at Metal Oxide Surfaces: Case Study of MgO (100)

We investigate effects of doping on formation energy and concentration of oxygen vacancies at a metal oxide surface, using MgO (100) as an example. Our approach employs density-functional theory, where the performance of the exchange-correlation functional is carefully analyzed, and the functional is chosen according to a fundamental condition on DFT ionization energies. The approach is further validated by CCSD(T) calculations for embedded clusters. We demonstrate that the concentration of oxygen vacancies at a doped oxide surface is largely determined by formation of a macroscopically extended space charge region

Genesis and Propagation of Fractal Structures During Photoelectrochemical Etching of n-Silicon

The genesis, propagation, and dimensions of fractal-etch patterns that form anodically on front- or back-illuminated n-Si(100) photoelectrodes in contact with 11.9 M NH₄F(aq) has been investigated during either linear-sweep voltammetry or when the electrode was held at a constant potential (E = +6.0 V versus Ag/AgCl). Optical images collected in situ during electrochemical experiments revealed the location and underlying mechanism of initiation and propagation of the structures on the surface. X-ray photoelectron spectroscopic (XPS) data collected for samples emersed from the electrolyte at varied times provided detailed information about the chemistry of the surface during fractal etching. The fractal structure was strongly influenced by the orientation of the crystalline Si sample. The etch patterns were initially generated at points along the circumference of bubbles that formed upon immersion of n-Si(100) samples in the electrolyte, most likely due to the electrochemical and electronic isolation of areas beneath bubbles. XPS data showed the presence of a tensile-stressed silicon surface throughout the etching process as well as the presence of SiO_xF_y on the surface. The two-dimensional fractal dimension D_(f,2D) of the patterns increased with etching time to a maximum observed value of D_(f,2D)=1.82. Promotion of fractal etching near etch masks that electrochemically and electronically isolated areas of the photoelectrode surface enabled the selective placement of highly branched structures at desired locations on an electrode surface

Halting Schistosoma haematobium - Associated Bladder Cancer

Background: At present schistosomiasis is endemic in 78 countries, affecting more than 260 million people. Schistosomiasis haematobia alone affects more than 112 millions. Evidence Acquisition: We performed a computerized search of in PubMed database with keywords: Bladder Cancer Cost and Schistosomiasis Mass Treatment. Results: Bladder cancer is an important sequelae of this infection. In low-resource countries, where this disease is endemic, individuals inflicted with bladder cancer have very limited access to treatment and death is most probably certain. Conclusions: Mass treatment with praziquantel is an easy, safe, and inexpensive treatment that could save the lives of thousands and reduce the morbidity of millions.info:eu-repo/semantics/publishedVersio

Photon counting intensity interferometry in the blue at a 0.5 m telescope

Intensity interferometry is a re-emerging interferometry tool that alleviates some of the challenges of amplitude interferometry at the cost of reduced sensitivity. We demonstrate the feasibility of intensity interferometry with fast single photon counting detectors at small telescopes by utilising a telescope of diameter of merely $0.5$\,m. The entire measurement setup, including collimation, optical filtering, and two single photon detectors, is attached directly to the telescope without the use of optical fibres, facilitated by the large area of our single photon detectors. For digitisation and timing, we utilise a Time-To-Amplitude-Converter. Observing $\alpha$ Lyrae (Vega) for a total exposure time of $32.4$\,h over the course of six nights, an auto-correlation signal with a contrast of $(9.5 \pm 2.7) \times 10^-3$ and a coherence time of $(0.34 \pm 0.12)$ ps at a SNR of 2.8 is measured. The result fits well to preceding laboratory tests as well as expectations calculated from the optical and electronic characteristics of our measurement setup. This measurement, to our knowledge, constitutes the first time that a bunching signal with starlight was measured in the B band with single photon counting detectors. Simultaneously, this is to date the stellar intensity interferometry measurement utilising the smallest telescope. Our successful measurement shows that intensity interferometry can be adopted not only at large scale facilities, but also at readily available and inexpensive smaller telescopes

Conductance of a molecular junction mediated by unconventional metal-induced gap states

The conductance of a molecular junction is commonly determined by either charge-transfer-doping, where alignment of the Fermi energy to the molecular levels is achieved, or tunnelling through the tails of molecular resonances within the highest-occupied and lowest-unoccupied molecular-orbital gap. Here, we present an alternative mechanism where electron transport is dominated by electrode surface states. They give rise to metallization of the molecular bridge and additional, pronounced conductance resonances allowing for substantial tailoring of its electronic properties via, e.g. a gate voltage. This is demonstrated in a field-effect geometry of a fullerene-bridge between two metallic carbon nanotubes.Comment: 7 pages, 5 figures included; to be published in Europhys. Let

Commentary: Human Liver Flukes

Free PMC Article: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5936791/pdf/fpubh-06-00122.pdfA commentary on: Human Liver Flukes by Harrington D, Lamberton P, McGregor A. Lancet Gastroenterol Hepatol (2017) 2:680–9. doi: 10.1016/S2468-1253(17)30111-5We read with interest the paper by Harrington et al. on “human liver flukes,” recently published in the Lancet Gastroenterology and Hepatology. They report that the prevalence of Fasciola hepatica in the inner Porto area of Portugal is 3.2%. These authors also state that this is a notably high prevalence. Fascioliasis, as a neglected tropical disease, commonly affects poor people from developing countries and occurs sporadically in Europe. In 1996, Dias et al. reported a case of chronic fascioliasis in a patient with a 6-year history of intermittent biliary colic after having ingested uncooked wild watercress. Our group has performed a search in the database of Centro Hospitalar de S. João (CHSJ), from 1997 to 2017. CHSJ is the biggest hospital in the North of Portugal. This hospital is located in the city of Porto and serves a population of 1,700,000 inhabitants distributed by an approximate area of 2,040 km2. The results we have obtained diverge from the figures reported by Harrington et al.: during the last 20 years only four cases of fascioliasis have been recorded: one case in 1998, one case in 2003, and two cases in 2014.info:eu-repo/semantics/publishedVersio