Interference effects in one-dimensional moiré crystals

Interference effects in finite sections of one-dimensional moiré crystals are investigated using a Landauer-Büttiker formalism within the tight-binding approximation. We explain interlayer transport in double-wall carbon nanotubes and design a predictive model. Wave function interference is visible at the mesoscale: in the strong coupling regime, as a periodic modulation of quantum conductance and emergent localized states; in the localized-insulating regime, as a suppression of interlayer transport, and oscillations of the density of states. These results could be exploited to design quantum electronic devices. © 2021 The Author

GW band structure of InAs and GaAs in the wurtzite phase

We report the first quasiparticle calculations of the newly observed wurtzite polymorph of InAs and GaAs. The calculations are performed in the GW approximation using plane waves and pseudopotentials. For comparison we also report the study of the zinc-blende phase within the same approximations. In the InAs compound the In 4d electrons play a very important role: whether they are frozen in the core or not, leads either to a correct or a wrong band ordering (negative gap) within the Local Density Appproximation (LDA). We have calculated the GW band structure in both cases. In the first approach, we have estimated the correction to the pd repulsion calculated within the LDA and included this effect in the calculation of the GW corrections to the LDA spectrum. In the second case, we circumvent the negative gap problem by first using the screened exchange approximation and then calculating the GW corrections starting from the so obtained eigenvalues and eigenfunctions. This approach leads to a more realistic band-structure and was also used for GaAs. For both InAs and GaAs in the wurtzite phase we predict an increase of the quasiparticle gap with respect to the zinc-blende polytype.Comment: 9 pages, 6 figures, 3 table

Behavioural Evidence and Chemical Identification of a Female Sex Pheromone in Anagrus atomus (Hymenoptera: Mymaridae)

Anagrus atomus (L.) is an egg parasitoid involved in the biological control of Empoasca vitis (G\uf6the) in vineyards. Sex pheromones play a crucial role in mate finding for several parasitoid species and could be used for monitoring under field conditions. We carried out laboratory and field studies aimed at assessing the existence and identity of a possible A. atomus sex pheromone. We found that males were significantly attracted by virgin females independent of age. Males were not attracted to individuals of the same sex, but they were attracted by a crude extract from an unmated female and its polar fraction. Eugenol (4-allyl-2-methoxyphenol) was identified as the attractive substance and proved to be attractive not only in the olfactometer but also in another laboratory bioassay and under field conditions. Attraction of males, but not females, confirms that this is not an aggregation pheromone. This is the first sex-pheromone component identified in Mymaridae, however more compounds could be involved in the mating behaviour of A. atomus. The utility of a sex pheromone in A. atomus is discussed in the context of fitness returns

Santa Bárbara, una cofradía de indios en San Antonio de Humahuaca (1713-1785)

Study on the functioning of Santa Barbara brotherhood pertaining to the town of Indians Humahuaca, jurisdiction of colonial Tucumán during the 18th century.Estudio sobre el funcionamiento de la cofradía de Santa Bárbara del pueblo de indios de Humahuaca, jurisdicción del Tucumán colonial, durante el siglo XVIII.  Palabras clave: Cofradías, pueblos de indios, Humahuaca, Tucumán. 

Deafness: from suspicion to referral for intervention

OBJECTIVE: To investigate the experiences of mothers concerning the suspicion of deafness, the diagnosis and the referral to rehabilitation, as well as their perception about how the diagnosis was presented and explained. METHODS: Qualitative study with ten hearing mothers of deaf children who attended specialized treatment at São Paulo State, Brazil, for at least two years. A semi-structured interview with the mothers was performed and data were analyzed by examining of participants speeches, seeking to understand the meaning that mothers attributed to their own words. RESULTS: Although the diagnosis of six children was done before 12 months of age and considering mothers' multiple feelings on facing the deafness of their children, earlier diagnosis would have been possible if maternal observations have been given adequate value. Health professionals showed some difficulties in listening mothers' doubts, complaints and inquiries. In some cases, even when the diagnosis of deafness was appropriate by newborn hearing screening or clinical tools, children's treatment was delayed because referrals for specialized centers were inadequate. At the moment of communicating the problem, social, cultural and emotional needs of the mothers were not considered. CONCLUSIONS: The qualification and attention of health professionals is important to enable the early diagnosis of deafness, allowing appropriate support for the family and patients' referral and follow-up.OBJETIVO: Investigar a vivência das mães entre a suspeita, o diagnóstico de surdez e o encaminhamento para habilitação, bem como a percepção delas a respeito da forma como foi dado e explicado o diagnóstico. MÉTODOS: Estudo qualitativo com dez mães ouvintes com filhos surdos que frequentavam atendimento especializado em Centro de Estudos e Pesquisas em Reabilitação, no estado de São Paulo, há pelo menos dois anos. Realizou-se entrevista semiestruturada com as mães e foi feita análise da fala das participantes, buscando compreender o sentido que as mães deram à sua comunicação. RESULTADOS: Apesar do diagnóstico de seis crianças ter sido feito antes de um ano de idade e, considerando-se os múltiplos sentimentos das mães frente à surdez de seus filhos, observou-se que, em alguns casos, o diagnóstico poderia ter ocorrido antes se a fala das mães fosse valorizada. Percebeu-se dificuldade de escuta dos profissionais da saúde em relação às dúvidas, queixas e questionamentos das mães. Constatou-se que, em alguns casos, mesmo quando ocorreu a triagem auditiva neonatal ou o diagnóstico oportuno, retardou-se o atendimento à criança porque não foram feitos encaminhamentos adequados para locais que trabalham na área da surdez. No momento do diagnóstico, a forma como foi comunicada a surdez à família necessitaria levar em consideração as condições sociais, culturais e emocionais das mães. CONCLUSÕES: Ressalta-se a importância da qualificação e atenção dos profissionais de saúde, para possibilitar o diagnóstico precoce, o apoio aos pais e o encaminhamento e seguimento adequados para os casos de surdez.OBJETIVO: Investigar la vivencia de las madres entre la sospecha, el diagnóstico de sordera y el encaminamiento para habilitación, así como la percepción de ellas respecto a la forma como se dio y explicó el diagnóstico. MÉTODOS: Estudio cualitativo con diez madres oyentes con hijos sordos que frecuentaban atención especializada en Centro de Estudios e Investigaciones en Rehabilitación, en la provincia de São Paulo, hace como mínimo dos años. Se realizó entrevista semiestructurada con las madres y se hizo análisis del habla de las participantes, buscando comprender el sentido que las madres dieron a su comunicación. RESULTADOS: A pesar del diagnóstico de seis niños haber sido realizado antes de un año de edad y teniendo en cuenta los múltiples sentimientos de las madres frente a la sordera de los hijos, se observó que en algunos casos el diagnóstico podría haber ocurrido antes si el habla de las madres fuera valorada. Se percibió la dificultad de «escucha» de los profesionales de la salud respecto a las dudas, quejas y cuestionamientos de las madres. Se constató que, en algunos casos, aun cuando tuvo lugar la selección auditiva neonatal o el diagnóstico oportuno, se retardó la atención al niño porque no se hicieron encaminamientos adecuados para locales que trabajan en el área de la sordera. En el momento del diagnóstico, la forma como se comunicó la sordera a la familia necesitaría tener en cuenta las condiciones sociales, culturales y emocionales de las madres. CONCLUSIONES: Se subraya la importancia de la cualificación y atención de los profesionales de salud, para hacer posible el diagnóstico temprano, el apoyo a los padres y el encaminamiento y seguimiento adecuados para los casos de sordera.25726

Manipulation of spin transport in graphene/transition metal dichalcogenide heterobilayers upon twisting

Proximity effects are one of the pillars of exotic phenomena and technological applications of two dimensional materials. However, the interactions nature depends strongly on the materials involved, their crystalline symmetries, and interfacial properties. Here we used large-scale first-principle calculations to demonstrate that strain and twist-angle are efficient knobs to tailor the spin-orbit coupling in graphene transition metal dichalcogenide heterobilayers. We found that by choosing a twist-angle of 30 degrees, the spin relaxation times increase by two orders of magnitude, opening a path to improve these heterostructures spin transport capability. Moreover, we demonstrate that strain and twist angle will modify the relative values of valley-Zeeman and Rashba spin-orbit coupling, allowing to tune the system into an ideal Dirac-Rashba regime. These results enable us to envision an answer for the variability of spin-orbit coupling found in different experiments and have significant consequences for applications that depend on polycrystallinity, where grains form at different orientations

Feasibility Study of a Neutron Time Of Flight Facility at the CERN-PS

This report summarises the feasibility study of a neutron time-of-flight facility at the CERN-PS as described in Refs. [1] and [2]. The idea is to extract at 24 GeV/cproton bunches (r.m.s. length ~7 ns) on to a target. The neutrons produced by spallation are directed to an experimental area located 230 m downstream throughout a vacuum pipe (diameter ~80 cm) making use of the existing TT2A tunnel about 7 m below the ISR tunne

Virtual histological assessment of the prenatal life history and age at death of the Upper Paleolithic fetus from Ostuni (Italy)

The fetal remains from the Ostuni 1 burial (Italy, ca 27 ka) represent a unique opportunity to explore the prenatal biological parameters, and to reconstruct the possible patho-biography, of a fetus (and its mother) in an Upper Paleolithic context. Phase-contrast synchrotron X-ray microtomography imaging of two deciduous tooth crowns and microfocus CT measurements of the right hemimandible of the Ostuni 1b fetus were performed at the SYRMEP beamline and at the TomoLab station of the Elettra - Sincrotrone laboratory (Trieste, Italy) in order to refne age at death and to report the enamel developmental history and dental tissue volumes for this fetal individual. The virtual histology allowed to estimate the age at death of the fetus at 31–33 gestational weeks. Three severe physiological stress episodes were also identifed in the prenatal enamel. These stress episodes occurred during the last two months and half of pregnancy and may relate to the death of both individuals. Compared with modern prenatal standards, Os1b’s skeletal development was advanced. This cautions against the use of modern skeletal and dental references for archaeological fnds and emphasizes the need for more studies on prenatal archaeological skeletal samples

Transcriptome profiling of the rice blast fungus during invasive plant infection and in vitro stresses

<p>Abstract</p> <p>Background</p> <p>Rice blast is the most threatening disease to cultivated rice. <it>Magnaporthe oryzae</it>, its causal agent, is likely to encounter environmental challenges during invasive growth in its host plants that require shifts in gene expression to establish a compatible interaction. Here, we tested the hypothesis that gene expression patterns during <it>in planta </it>invasive growth are similar to <it>in vitro </it>stress conditions, such as nutrient limitation, temperature up shift and oxidative stress, and determined which condition most closely mimicked that of <it>in planta </it>invasive growth. Gene expression data were collected from these <it>in vitro </it>experiments and compared to fungal gene expression during the invasive growth phase at 72 hours post-inoculation in compatible interactions on two grass hosts, rice and barley.</p> <p>Results</p> <p>We identified 4,973 genes that were differentially expressed in at least one of the <it>in planta </it>and <it>in vitro </it>stress conditions when compared to fungal mycelia grown in complete medium, which was used as reference. From those genes, 1,909 showed similar expression patterns between at least one of the <it>in vitro </it>stresses and rice and/or barley. Hierarchical clustering of these 1,909 genes showed three major clusters in which <it>in planta </it>conditions closely grouped with the nutrient starvation conditions. Out of these 1,909 genes, 55 genes and 129 genes were induced and repressed in all treatments, respectively. Functional categorization of the 55 induced genes revealed that most were either related to carbon metabolism, membrane proteins, or were involved in oxidoreduction reactions. The 129 repressed genes showed putative roles in vesicle trafficking, signal transduction, nitrogen metabolism, or molecular transport.</p> <p>Conclusions</p> <p>These findings suggest that <it>M. oryzae </it>is likely primarily coping with nutrient-limited environments at the invasive growth stage 72 hours post-inoculation, and not with oxidative or temperature stresses.</p

Realization of vertically aligned, ultra-high aspect ratio InAsSb nanowires on graphite

The monolithic integration of InAs1–xSbx semiconductor nanowires on graphitic substrates holds enormous promise for cost-effective, high-performance, and flexible devices in optoelectronics and high-speed electronics. However, the growth of InAs1–xSbx nanowires with high aspect ratio essential for device applications is extremely challenging due to Sb-induced suppression of axial growth and enhancement in radial growth. We report the realization of high quality, vertically aligned, nontapered and ultrahigh aspect ratio InAs1–xSbx nanowires with Sb composition (xSb(%)) up to ∼12% grown by indium-droplet assisted molecular beam epitaxy on graphite substrate. Low temperature photoluminescence measurements show that the InAs1–xSbx nanowires exhibit bright band-to-band related emission with a distinct redshift as a function of Sb composition providing further confirmation of successful Sb incorporation in as-grown nanowires. This study reveals that the graphite substrate is a more favorable platform for InAs1–xSbx nanowires that could lead to hybrid heterostructures possessing potential device applications in optoelectronics