Strong Spin-Orbit Interaction Induced in Graphene by Monolayer WS2_2

We demonstrate strong anisotropic spin-orbit interaction (SOI) in graphene induced by monolayer WS$_2$. Direct comparison between graphene/monolayer WS$_2$ and graphene/bulk WS$_2$ system in magnetotransport measurements reveals that monolayer transition metal dichalcogenide (TMD) can induce much stronger SOI than bulk. Detailed theoretical analysis of the weak-antilocalization curves gives an estimated spin-orbit energy ($E_{\rm so}$) higher than 10 meV. The symmetry of the induced SOI is also discussed, and the dominant $z$ $\rightarrow$ $-z$ symmetric SOI can only explain the experimental results. Spin relaxation by the Elliot-Yafet (EY) mechanism and anomalous resistance increase with temperature close to the Dirac point indicates Kane-Mele (KM) SOI induced in graphene.Comment: 5 pages, 4 figure

More Real than Real: A Study on Human Visual Perception of Synthetic Faces

Deep fakes became extremely popular in the last years, also thanks to their increasing realism. Therefore, there is the need to measures human's ability to distinguish between real and synthetic face images when confronted with cutting-edge creation technologies. We describe the design and results of a perceptual experiment we have conducted, where a wide and diverse group of volunteers has been exposed to synthetic face images produced by state-of-the-art Generative Adversarial Networks (namely, PG-GAN, StyleGAN, StyleGAN2). The experiment outcomes reveal how strongly we should call into question our human ability to discriminate real faces from synthetic ones generated through modern AI

Selección de trabajos de estudiantes de la Maestría en Relaciones Internacionales del IRI (año 2015/2016)

Como ya hemos venido haciendo, la presente publicación busca recuperar, seleccionar y visibilizar algunos de los más destacados trabajos realizados, entre los años 2015 y el 2016, por los/as alumnos/as de la Maestría en Relaciones Internacionales del IRI, UNLP. Dichos ensayos responden a diversas áreas de estudio, a saber: África en las Relaciones Internacionales, Medio Oriente en la Política Internacional, Cáucaso y Asia Central Contemporáneo, América Latina en las Relaciones Internacionales y Terrorismo contemporáneo. En este sentido, es importante destacar que tanto los recortes geográficos y temporales, como la metodología y teoría empleadas, también son variados. Asimismo, cabe aclarar que algunos/as autores/as han realizado actualizaciones de datos, a fin de optimizar el resultado final de sus escritos. En otro orden, nos es grato contar en esta compilación con la presencia de alumnos/as de distintas latitudes. De este modo, de los seis trabajos que presentamos en esta ocasión, cuatro pertenecen a extranjeros/ as: dos de Chile y dos de Francia. Esta pequeña muestra de interculturalidad pretende a su vez ser una expresión de lo que perseguimos desde el Instituto de Relaciones Internacionales: un espacio de formación superior de la Universidad Nacional de La Plata, receptor de profesionales de todo el mundo. Creemos que es justamente en ese intercambio de experiencias y diálogos de ideas y saberes desde donde mejor podemos posicionarnos para pensar a las RRII, en una época de constantes cambios, disputas de poder y quiebres de antiguos paradigmas. A continuación, comentaremos brevemente los textos que componen este Documento de trabajo. El primero de ellos es el de Cecilia Teruggi, y se titula “La transición estratégica de Arabia Saudita en materia petrolera: OPEP, revolución energética de Occidente y desafíos de la transformación del Reino”. Allí la autora nos describe el contexto de debilitamiento que sufrió la Organización de Países Productores de Petróleo, entre el 2014 y el 2017, y qué postura y acciones tomó el Reino como líder de la OPEP. Además de la exhaustividad del relato, el texto de Cecilia nos permite evidenciar cómo el mercado petrolero se ve condicionado por los cambios políticos en todos los niveles (doméstico, regional e internacional). Por su parte, el trabajo “Las políticas de la Unión Europea en materia de lucha contra la radicalización, desde sus inicios hasta 2014”, de Hélène Lavillauroy, analiza las decisiones políticas europeas contra el terrorismo, desde las primeras expresiones hasta el ataque de Charlie Hebdo, en enero de 2015. Pensar en estas nuevas amenazas nacionales y transnacionales nos lleva a ubicarnos en un mundo complejo, donde la imprevisibilidad es una característica de estas nuevas formas de violencia. En este contexto, donde se hace evidente el fracaso de la integración –los protagonistas de los atentados son parte de una segunda generación de inmigrantes en países como Francia y Bélgica- , Hélène nos advierte que las acciones de la Unión Europea no son determinantes para acabar con este flagelo social, y que sólo limita su rol al apoyo de sus Estados miembros. Por otro lado, Irma Henríquez Díaz, con su ensayo “Los aportes del Africanocentrismo y la Intelectualidad africana como alternativas frente al Eurocentrismo”, se propone problematizar sobre las herramientas que la intelectualidad africana presenta para pensar su propia historia y sus procesos. En este sentido, la autora chilena descata la propuesta teórica de Molefi Kete Asante, quien propone entender al Africanocentrismo tanto como un nuevo posicionamiento cultural y analítico para la realidad de la región; como un paradigma antropológico, sociológico, político e histórico, que elabora una crítica al binomio eurocentrismooccidentalismo, para el estudio de la cultura señalada. Lucas Pavez Rosales, en cambio, nos presenta un análisis que se enmarca en el Cono Sur. Con su texto “¿Un Siglo de Concertación y Proyección Regional? Equilibrios de Poder y Procesos de Integración entre Argentina, Brasil y Chile (1915-2015)”, analiza tres episodios históricos, para sustentar su hipótesis sobre un equilibrio de poder que impide la consolidación de un solo país como hegemón de Sudamérica. Así, los hechos estudiados por este historiador son: 1) el contexto de la firma del Pacto ABC en 1915; 2) el intento de alianza ABC de Perón en 1953; y 3) la creación de Unasur en el siglo XXI como nueva forma de integración regional. En otro orden, Matías Caubet, con su trabajo “Las relaciones sino-rusas y la Organización de Cooperación de Shanghái como un primer eje de análisis sobre la cuestión”, se pregunta sobre el rol de dicha Organización en el panorama internacional actual. El interrogante surge porque, tal como advierte el autor, la aparición de la OCS “es una clara muestra de la aparición de nuevas potencias que comienzan a suponer un reto y un desafío a la, otrora, hegemonía estadounidense en el sistema-mundo”. En esta complejidad, Matías nos aclara que el caso seleccionado también puede ser considerado un ejemplo de que no existen intereses homogéneos entre los nuevos retadores. De ahí que el desafío sea tan grande. Finalmente, Rosalía Arguelles nos presenta su artículo “Guaraníes, identidad nacional y diplomacia de los pueblos en Argentina Paraguay y Brasil”, donde realiza un interesante recorrido histórico por el rol de los guaraníes, en tanto pueblo originario transzonal en la identidad nacional del Cono Sur. En esta línea, la autora parte de la afirmación que Argentina, Paraguay y Brasil construyeron su ideal de Nación definiendo jurídicamente y culturalmente a los guaraníes. Asimismo, algunos de los interrogantes que se propone ir respondiendo Rosalía a lo largo de su ensayo, son: ¿En cuál de estos tres países las luchas por la tierra y el medioambiente son más activas?; ¿cuáles juegan a nivel global?; ¿cómo esas luchas modifican el tablero de la política exterior? y ¿cuál es su influencia a nivel Cono Sur y MERCOSUR?Instituto de Relaciones Internacionale

Four main virotypes among extended-spectrum-β-lactamase-producing isolates of Escherichia coli O25b:H4-B2-ST131: bacterial, epidemiological, and clinical characteristics

A total of 1,021 extended-spectrum- -lactamase-producing Escherichia coli (ESBLEC) isolates obtained in 2006 during a Spanish national survey conducted in 44 hospitals were analyzed for the presence of the O25b:H4-B2-ST131 (sequence type 131) clonal group. Overall, 195 (19%) O25b-ST131 isolates were detected, with prevalence rates ranging from 0% to 52% per hospital. Molecular characterization of 130 representative O25b-ST131 isolates showed that 96 (74%) were positive for CTX-M-15, 15 (12%) for CTX-M-14, 9 (7%) for SHV-12, 6 (5%) for CTX-M-9, 5 (4%) for CTX-M-32, and 1 (0.7%) each for CTX-M-3 and the new ESBL enzyme CTX-M-103. The 130 O25b-ST131 isolates exhibited relatively high virulence scores (mean, 14.4 virulence genes). Although the virulence profiles of the O25b-ST131 isolates were fairly homogeneous, they could be classified into four main virotypes based on the presence or absence of four distinctive virulence genes: virotypes A (22%) (afa FM955459 positive, iroN negative, ibeA negative, sat positive or negative), B (31%) (afa FM955459 negative, iroN positive, ibeA negative, sat positive or negative), C (32%) (afa FM955459 negative, iroN negative, ibeA negative, sat positive), and D (13%) (afa FM955459 negative, iroN positive or negative, ibeA positive, sat positive or negative). The four virotypes were also identified in other countries, with virotype C being overrepresented internationally. Correspondingly, an analysis of XbaI macrorestriction profiles revealed four major clusters, which were largely virotype specific. Certain epidemiological and clinical features corresponded with the virotype. Statistically significant virotype-specific associations included, for virotype B, older age and a lower frequency of infection (versus colonization), for virotype C, a higher frequency of infection, and for virotype D, younger age and community-acquired infections. In isolates of the O25b:H4-B2-ST131 clonal group, these findings uniquely define four main virotypes, which are internationally distributed, correspond with pulsed-field gel electrophoresis (PFGE) profiles, and exhibit distinctive clinical-epidemiological association

The Seabed Makes the Dolphins: Physiographic Features Shape the Size and Structure of the Bottlenose Dolphin Geographical Units

The common bottlenose dolphin (Tursiops truncatus) is a cosmopolitan delphinid, regularly present in the Mediterranean Sea. According to previous studies, this dolphin tends to form resident geographical units scattered on the continental shelf. We investigated how the physiographic characteristics of the area of residence, with special reference to the size and shape of the continental shelf, affect the home range and the group size of the local units. We analysed and compared data collected between 2004-2016 by 15 research groups operating in different study areas of the Mediterranean Sea: the Alboran Sea, in the South-Western Mediterranean, the Gulf of Lion and the Pelagos Sanctuary for the marine mammals, in the North-Western Mediterranean, and the Gulf of Ambracia, in the North-Central Mediterranean Sea. We have found that in areas characterised by a wide continental platform, dolphins have wider home ranges and aggregate into larger groups. In areas characterized by a narrow continental platform, dolphins show much smaller home ranges and aggregate into smaller groups. The results obtained from this collective research effort highlight the importance of data sharing to improve our scientific knowledge in the field of cetaceans and beyond

A population of gamma-ray emitting globular clusters seen with the Fermi Large Area Telescope

Globular clusters with their large populations of millisecond pulsars (MSPs) are believed to be potential emitters of high-energy gamma-ray emission. Our goal is to constrain the millisecond pulsar populations in globular clusters from analysis of gamma-ray observations. We use 546 days of continuous sky-survey observations obtained with the Large Area Telescope aboard the Fermi Gamma-ray Space Telescope to study the gamma-ray emission towards 13 globular clusters. Steady point-like high-energy gamma-ray emission has been significantly detected towards 8 globular clusters. Five of them (47 Tucanae, Omega Cen, NGC 6388, Terzan 5, and M 28) show hard spectral power indices $(0.7 < \Gamma <1.4)$ and clear evidence for an exponential cut-off in the range 1.0-2.6 GeV, which is the characteristic signature of magnetospheric emission from MSPs. Three of them (M 62, NGC 6440 and NGC 6652) also show hard spectral indices $(1.0 < \Gamma < 1.7)$, however the presence of an exponential cut-off can not be unambiguously established. Three of them (Omega Cen, NGC 6388, NGC 6652) have no known radio or X-ray MSPs yet still exhibit MSP spectral properties. From the observed gamma-ray luminosities, we estimate the total number of MSPs that is expected to be present in these globular clusters. We show that our estimates of the MSP population correlate with the stellar encounter rate and we estimate 2600-4700 MSPs in Galactic globular clusters, commensurate with previous estimates. The observation of high-energy gamma-ray emission from a globular cluster thus provides a reliable independent method to assess their millisecond pulsar populations that can be used to make constraints on the original neutron star X-ray binary population, essential for understanding the importance of binary systems in slowing the inevitable core collapse of globular clusters.Comment: Accepted for publication in A&A. Corresponding authors: J. Kn\"odlseder, N. Webb, B. Pancraz

Diagnostic accuracy of pulmonary host inflammatory mediators in the exclusion of ventilator-acquired pneumonia.

BACKGROUND: Excessive use of empirical antibiotics is common in critically ill patients. Rapid biomarker-based exclusion of infection may improve antibiotic stewardship in ventilator-acquired pneumonia (VAP). However, successful validation of the usefulness of potential markers in this setting is exceptionally rare. OBJECTIVES: We sought to validate the capacity for specific host inflammatory mediators to exclude pneumonia in patients with suspected VAP. METHODS: A prospective, multicentre, validation study of patients with suspected VAP was conducted in 12 intensive care units. VAP was confirmed following bronchoscopy by culture of a potential pathogen in bronchoalveolar lavage fluid (BALF) at >10(4) colony forming units per millilitre (cfu/mL). Interleukin-1 beta (IL-1β), IL-8, matrix metalloproteinase-8 (MMP-8), MMP-9 and human neutrophil elastase (HNE) were quantified in BALF. Diagnostic utility was determined for biomarkers individually and in combination. RESULTS: Paired BALF culture and biomarker results were available for 150 patients. 53 patients (35%) had VAP and 97 (65%) patients formed the non-VAP group. All biomarkers were significantly higher in the VAP group (p<0.001). The area under the receiver operator characteristic curve for IL-1β was 0.81; IL-8, 0.74; MMP-8, 0.76; MMP-9, 0.79 and HNE, 0.78. A combination of IL-1β and IL-8, at the optimal cut-point, excluded VAP with a sensitivity of 100%, a specificity of 44.3% and a post-test probability of 0% (95% CI 0% to 9.2%). CONCLUSIONS: Low BALF IL-1β in combination with IL-8 confidently excludes VAP and could form a rapid biomarker-based rule-out test, with the potential to improve antibiotic stewardship

Gamma-ray and radio properties of six pulsars detected by the fermi large area telescope

We report the detection of pulsed γ-rays for PSRs J0631+1036, J0659+1414, J0742-2822, J1420-6048, J1509-5850, and J1718-3825 using the Large Area Telescope on board the Fermi Gamma-ray Space Telescope (formerly known as GLAST). Although these six pulsars are diverse in terms of their spin parameters, they share an important feature: their γ-ray light curves are (at least given the current count statistics) single peaked. For two pulsars, there are hints for a double-peaked structure in the light curves. The shapes of the observed light curves of this group of pulsars are discussed in the light of models for which the emission originates from high up in the magnetosphere. The observed phases of the γ-ray light curves are, in general, consistent with those predicted by high-altitude models, although we speculate that the γ-ray emission of PSR J0659+1414, possibly featuring the softest spectrum of all Fermi pulsars coupled with a very low efficiency, arises from relatively low down in the magnetosphere. High-quality radio polarization data are available showing that all but one have a high degree of linear polarization. This allows us to place some constraints on the viewing geometry and aids the comparison of the γ-ray light curves with high-energy beam models

Polygenic risk scores and breast and epithelial ovarian cancer risks for carriers of BRCA1 and BRCA2 pathogenic variants

Purpose We assessed the associations between population-based polygenic risk scores (PRS) for breast (BC) or epithelial ovarian cancer (EOC) with cancer risks forBRCA1andBRCA2pathogenic variant carriers. Methods Retrospective cohort data on 18,935BRCA1and 12,339BRCA2female pathogenic variant carriers of European ancestry were available. Three versions of a 313 single-nucleotide polymorphism (SNP) BC PRS were evaluated based on whether they predict overall, estrogen receptor (ER)-negative, or ER-positive BC, and two PRS for overall or high-grade serous EOC. Associations were validated in a prospective cohort. Results The ER-negative PRS showed the strongest association with BC risk forBRCA1carriers (hazard ratio [HR] per standard deviation = 1.29 [95% CI 1.25-1.33],P = 3x10(-72)). ForBRCA2, the strongest association was with overall BC PRS (HR = 1.31 [95% CI 1.27-1.36],P = 7x10(-50)). HR estimates decreased significantly with age and there was evidence for differences in associations by predicted variant effects on protein expression. The HR estimates were smaller than general population estimates. The high-grade serous PRS yielded the strongest associations with EOC risk forBRCA1(HR = 1.32 [95% CI 1.25-1.40],P = 3x10(-22)) andBRCA2(HR = 1.44 [95% CI 1.30-1.60],P = 4x10(-12)) carriers. The associations in the prospective cohort were similar. Conclusion Population-based PRS are strongly associated with BC and EOC risks forBRCA1/2carriers and predict substantial absolute risk differences for women at PRS distribution extremes.Peer reviewe

An original phylogenetic approach identified mitochondrial haplogroup T1a1 as inversely associated with breast cancer risk in BRCA2 mutation carriers

Introduction: Individuals carrying pathogenic mutations in the BRCA1 and BRCA2 genes have a high lifetime risk of breast cancer. BRCA1 and BRCA2 are involved in DNA double-strand break repair, DNA alterations that can be caused by exposure to reactive oxygen species, a main source of which are mitochondria. Mitochondrial genome variations affect electron transport chain efficiency and reactive oxygen species production. Individuals with different mitochondrial haplogroups differ in their metabolism and sensitivity to oxidative stress. Variability in mitochondrial genetic background can alter reactive oxygen species production, leading to cancer risk. In the present study, we tested the hypothesis that mitochondrial haplogroups modify breast cancer risk in BRCA1/2 mutation carriers. Methods: We genotyped 22,214 (11,421 affected, 10,793 unaffected) mutation carriers belonging to the Consortium of Investigators of Modifiers of BRCA1/2 for 129 mitochondrial polymorphisms using the iCOGS array. Haplogroup inference and association detection were performed using a phylogenetic approach. ALTree was applied to explore the reference mitochondrial evolutionary tree and detect subclades enriched in affected or unaffected individuals. Results: We discovered that subclade T1a1 was depleted in affected BRCA2 mutation carriers compared with the rest of clade T (hazard ratio (HR) = 0.55; 95% confidence interval (CI), 0.34 to 0.88; P = 0.01). Compared with the most frequent haplogroup in the general population (that is, H and T clades), the T1a1 haplogroup has a HR of 0.62 (95% CI, 0.40 to 0.95; P = 0.03). We also identified three potential susceptibility loci, including G13708A/rs28359178, which has demonstrated an inverse association with familial breast cancer risk. Conclusions: This study illustrates how original approaches such as the phylogeny-based method we used can empower classical molecular epidemiological studies aimed at identifying association or risk modification effects.Peer reviewe