Landauer-B\"uttiker Study of the Anomalous Hall Effect

We report on Landauer-B\"uttiker studies of anomalous Hall transport in a two-dimensional electron gas with Rashba spin-orbit coupling and a magnetization provided by localized magnetic moments. Our system is described by a discretized tight-binding model in a four-terminal geometry. We consider both the case of magnetically disordered systems as well as ballistic transport in disorder-free systems with spatially homoge- neous magnetization. In the latter case we investigate both out-of-plane and in-plane magnetizations. We numerically establish a close connection between singularities in the density of states and peaks in the Hall conductance close to the lower band edge. Consistent with previous theoretical studies based on diagrammatic perturbation expansions, these peaks occur at Fermi energies where only the lower dispersion branch is occupied. Moreover, for large magnetization the Hall conductance is, along with the density of states, sup- pressed. This numerical finding can be understood from analytical properties of the underlying model in the limit of an infinite system.Comment: 10 pages, 13 figures. Published Phys. Rev. B 80, 155321 (2009

Fast Quantum Computing with Buckyballs

We have found that encapsulated atoms in fullerene molecules, which carry a spin, can be used for fast quantum computing. We describe the scheme for performing quantum computations, going through the preparation of the qubit state and the realization of a two-qubit quantum gate. When we apply a static magnetic field to each encased spin, we find out the ideal design for the preparation of the quantum state. Therefore, adding to our system a time dependent magnetic field, we can perform a phase-gate. The operational time related to a $\pi-$phase gate is of the order of $ns$. This finding shows that, during the decoherence time, which is proportional to $\mu s$, we can perform many thousands of gate operations. In addition, the two-qubit state which arises after a $\pi-$gate is characterized by a high degree of entanglement. This opens a new avenue for the implementation of fast quantum computation.Comment: 9 pages, 4 figure

La sopravvivenza dei pazienti affetti da morbo di Addison in Italia

Introduction: Survival of patients affected by Addison’s Disease (AD) is controversial, because only few studies have been published so far. We decided to evaluate survival of an Italian group of patients, affected by AD of various causes. Materials and Methods: We examinated 1315 patients (58.6% females and 41.4% males) affected by AD, followed-by Endocrine Units all over Italy: the sum of follow-up years was 16983. 70.5% of patients has autoimmune AD (AAD), 113 with APS-1 and 814 with con AAD not APS-1 correlated (AAD not APS-1); 29.5% has non autoimmune AD, 98 of which with post-tuberculosis AD (TBC-AD), 50 with AD due to malignancy (Tu-AD), 97 with congenital AD (Ge-AD) and 143 with AD due to other causes (Ac-AD). We analyzed mean age of diagnosis, years of follow-up and mean age at the end of follow-up, survival was evaluated with Kaplan-Meier analysis and Cox regression. Results were correlated with Italian population data, correlated for sex and age (ISTAT register). We also performed a similar analysis considering only those patients who terminated the follow-up (1006 subjects). Results: In APS-1 patients, mean age of diagnosis is 16.1±13.8 years, with 15 deaths in 113 subjects (13.3%) at a mean age of 32.5±18.4 years and a mean estimated survival (MES) of 40.4±5.8 years; in MAA non APS-1, mean age of diagnosis is 35.7±14.4 years, with 18 deaths in 814 subjects (2.2%) at 77.9±13.3 years of age and a MES of 56.1±3.8 years; in TBC-AD, mean age of diagnosis is 50.1±15.7 years, with 11 deaths in 98 subjects (11.2%) at a mean age of 81.1±7.4 years and MES of 42.5±4.1 years; in Tu-AD, mean age of diagnosis is 57.9±15.5 years, with 12 deaths in 50 subjects (24%) at 65.6±14.4 years of age and a MES of 11.3±5.8 years; in Ge-AD, mean age of diagnosis is 7.3±10 years, with 4 deaths in 97 subjects (4.1%) at a mean age of 16.7±4.3 years and a MES of 41.1±1.8 years; in Ac-AD, mean age of diagnosis is 43±19.5 years, with 5 deaths in 143 subjects (3.5%) at a mean age of 55.2±40 years and a MES of 44.4±1.8 years. Comparing mean estimated survival of each subgroup with Italian matched population, only APS-1 and Tu-AD appear lower. Comparing subgroups head to head, Tu-AD patients’ survival is lower than all other groups (p<0.001), while survival of APS-1 and TBC-AD subgroups is lower than AAD non-APS-1 subgroups (p<0.001 and p=0.01, respectively); all other comparisons are not statistically different. Cox regression analysis, referring to AAD non-APS-1 subgroup, demonstrate an higher risk of mortality in APS-1 (HR 4.38, CI 2.18-8.8; p<0.001), TBC-AD (HR 2.99, CI 1.39-6.44; p=0.005) and Tu-AD (HR 47.88, CI 21.07-108.81; p<0.001). Survival analysis performed only on those patients who completed the follow-up results similar to the previous analysis. Conclusions: AD patients survival depends on ethiology of AD: in APS-1 and Tu-AD patients survival is lower than other subgroups and to the matched Italian population. In all other groups (AAD non-APS-1, TBC-AD, congenital AD and Ac-AD), survival is not different from matched Italian population

Multi-omics gut microbiome signatures in obese women: role of diet and uncontrolled eating behavior

Background: Obesity and related co-morbidities represent a major health challenge nowadays, with a rapidly increasing incidence worldwide. The gut microbiome has recently emerged as a key modifier of human health that can affect the development and progression of obesity, largely due to its involvement in the regulation of food intake and metabolism. However, there are still few studies that have in-depth explored the functionality of the human gut microbiome in obesity and even fewer that have examined its relationship to eating behaviors. Methods: In an attempt to advance our knowledge of the gut-microbiome-brain axis in the obese phenotype, we thoroughly characterized the gut microbiome signatures of obesity in a well-phenotyped Italian female cohort from the NeuroFAST and MyNewGut EU FP7 projects. Fecal samples were collected from 63 overweight/obese and 37 normal-weight women and analyzed via a multi-omics approach combining 16S rRNA amplicon sequencing, metagenomics, metatranscriptomics, and lipidomics. Associations with anthropometric, clinical, biochemical, and nutritional data were then sought, with particular attention to cognitive and behavioral domains of eating. Results: We identified four compositional clusters of the gut microbiome in our cohort that, although not distinctly associated with weight status, correlated differently with eating habits and behaviors. These clusters also differed in functional features, i.e., transcriptional activity and fecal metabolites. In particular, obese women with uncontrolled eating behavior were mostly characterized by low-diversity microbial steady states, with few and poorly interconnected species (e.g., Ruminococcus torques and Bifidobacterium spp.), which exhibited low transcriptional activity, especially of genes involved in secondary bile acid biosynthesis and neuroendocrine signaling (i.e., production of neurotransmitters, indoles and ligands for cannabinoid receptors). Consistently, high amounts of primary bile acids as well as sterols were found in their feces. Conclusions: By finding peculiar gut microbiome profiles associated with eating patterns, we laid the foundation for elucidating gut-brain axis communication in the obese phenotype. Subject to confirmation of the hypotheses herein generated, our work could help guide the design of microbiome-based precision interventions, aimed at rewiring microbial networks to support a healthy diet-microbiome-gut-brain axis, thus counteracting obesity and related complications

miRNA levels are associated with body mass index in endometrial cancer and may have implications for therapy

Endometrial cancer (EC) is the most prevalent gynecological cancer in high-income countries. Its incidence is skyrocketing due to the increase in risk factors such as obesity, which represents a true pandemic. This study aimed to evaluate microRNA (miRNA) expression in obesity-related EC to identify potential associations between this specific cancer type and obesity. miRNA levels were analyzed in 84 EC patients stratified based on body mass index (BMI; &gt;= 30 or &lt;30) and nine noncancer women with obesity. The data were further tested in The Cancer Genome Atlas (TCGA) cohort, including 384 EC patients, 235 with BMI &gt;= 30 and 149 with BMI &lt;30. Prediction of miRNA targets and analysis of their expression were also performed to identify the potential epigenetic networks involved in obesity modulation. In the EC cohort, BMI &gt;= 30 was significantly associated with 11 deregulated miRNAs. The topmost deregulated miRNAs were first analyzed in 84 EC samples by single miRNA assay and then tested in the TCGA dataset. This independent validation provided further confirmation about the significant difference of three miRNAs (miR-199a-5p, miR-449a, miR-449b-5p) in normal-weight EC patients versus EC patients with obesity, resulting significantly higher expressed in the latter. Moreover, the three miRNAs were significantly correlated with grade, histological type, and overall survival. Analysis of their target genes revealed that these miRNAs may regulate obesity-related pathways. In conclusion, we identified specific miRNAs associated with BMI that are potentially involved in modulating obesity-related pathways and that may provide novel implications for the clinical management of obese EC patients

Report of high insulin requirements in pediatric critically ill patients with COVID-19: Experience with continuous remote glucose monitoring

Los pacientes en estado crítico con COVID-19 sufren hiperglucemias sostenidas de difícil manejo. A esto se suma el desafío de minimizar la exposición al contagio. En el presente artículo analizamos la evolución metabólica de dos pacientes pediátricos con COVID-19 admitidos en unidad de cuidados intensivos (UCI) para pacientes COVID-19 del Hospital “Prof. Dr. Juan P. Garrahan” de la Ciudad Autónoma de Buenos Aires, Argentina, que requirieron tratamiento con insulina endovenosa y cuya glucemia fue monitoreada de manera remota con la plataforma InsuMate® desarrollada en la Universidad Nacional de La Plata. Los pacientes requirieron tasas de infusión de insulina en dosis marcadamente mayores que las de otros pacientes críticos que impresionaron relacionadas con los valores de marcadores de inflamación. La infusión pudo ajustarse con cuatro monitoreos diarios de glucosa y las métricas obtenidas con el monitor de glucosa. El uso del sistema de monitoreo remoto continuo de glucosa permitió disminuir la frecuencia de monitoreo glucémico durante el tratamiento.Critically ill patients with COVID-19 suffer from sustained hyperglycemia that is difficult to manage. Added to this is the challenge of minimizing exposure to contagion. In this article we analyze the metabolic evolution of two pediatric patients with COVID-19 admitted to the intensive care unit (ICU) for COVID-19 patients at the Hospital “Prof. Dr. Juan P. Garrahan ”from the Autonomous City of Buenos Aires, Argentina, who required treatment with intravenous insulin and whose blood glucose was remotely monitored with the InsuMate® platform developed at the National University of La Plata. The patients required insulin infusion rates in doses markedly higher than those of other critically ill patients, who were impressively related to the values of inflammation markers. The infusion could be adjusted with four daily glucose monitors and the metrics obtained with the glucose monitor. The use of the continuous remote glucose monitoring system made it possible to decrease the frequency of glycemic monitoring during treatment.Fil: Krochik, Andrea Gabriela. Gobierno de la Ciudad de Buenos Aires. Hospital de Pediatría "Juan P. Garrahan"; ArgentinaFil: Prieto, Mariana. Gobierno de la Ciudad de Buenos Aires. Hospital de Pediatría "Juan P. Garrahan"; ArgentinaFil: Martinez Mateu, Carolina. Gobierno de la Ciudad de Buenos Aires. Hospital de Pediatría "Juan P. Garrahan"; ArgentinaFil: Barcala, Consuelo. Gobierno de la Ciudad de Buenos Aires. Hospital de Pediatría "Juan P. Garrahan"; ArgentinaFil: Gallagher, Rosario. Gobierno de la Ciudad de Buenos Aires. Hospital de Pediatría "Juan P. Garrahan"; ArgentinaFil: Filippini, Silvia. Gobierno de la Ciudad de Buenos Aires. Hospital de Pediatría "Juan P. Garrahan"; ArgentinaFil: Arambarri, Delfina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones en Electrónica, Control y Procesamiento de Señales. Universidad Nacional de La Plata. Instituto de Investigaciones en Electrónica, Control y Procesamiento de Señales; ArgentinaFil: Mendoza, Leandro Ezequiel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones en Electrónica, Control y Procesamiento de Señales. Universidad Nacional de La Plata. Instituto de Investigaciones en Electrónica, Control y Procesamiento de Señales; ArgentinaFil: Rosales, Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones en Electrónica, Control y Procesamiento de Señales. Universidad Nacional de La Plata. Instituto de Investigaciones en Electrónica, Control y Procesamiento de Señales; ArgentinaFil: de Battista, Hernán. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones en Electrónica, Control y Procesamiento de Señales. Universidad Nacional de La Plata. Instituto de Investigaciones en Electrónica, Control y Procesamiento de Señales; ArgentinaFil: Sanchez Peña, Ricardo Salvador. Instituto Tecnológico de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Garelli, Fabricio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones en Electrónica, Control y Procesamiento de Señales. Universidad Nacional de La Plata. Instituto de Investigaciones en Electrónica, Control y Procesamiento de Señales; Argentin

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

Measurement of the dependence of transverse energy production at large pseudorapidity on the hard-scattering kinematics of proton-proton collisions at √s=2.76 TeV with ATLAS

The relationship between jet production in the central region and the underlying-event activity in a pseudorapidity-separated region is studied in 4.0 pb-1 of s=2.76 TeV pp collision data recorded with the ATLAS detector at the LHC. The underlying event is characterised through measurements of the average value of the sum of the transverse energy at large pseudorapidity downstream of one of the protons, which are reported here as a function of hard-scattering kinematic variables. The hard scattering is characterised by the average transverse momentum and pseudorapidity of the two highest transverse momentum jets in the event. The dijet kinematics are used to estimate, on an event-by-event basis, the scaled longitudinal momenta of the hard-scattered partons in the target and projectile beam-protons moving toward and away from the region measuring transverse energy, respectively. Transverse energy production at large pseudorapidity is observed to decrease with a linear dependence on the longitudinal momentum fraction in the target proton and to depend only weakly on that in the projectile proton. The results are compared to the predictions of various Monte Carlo event generators, which qualitatively reproduce the trends observed in data but generally underpredict the overall level of transverse energy at forward pseudorapidity

Measurements of the charge asymmetry in top-quark pair production in the dilepton final state at s √ =8 TeV with the ATLAS detector

Measurements of the top-antitop quark pair production charge asymmetry in the dilepton channel, characterized by two high-pT leptons (electrons or muons), are presented using data corresponding to an integrated luminosity of 20.3  fb−1 from pp collisions at a center-of-mass energy s√=8  TeV collected with the ATLAS detector at the Large Hadron Collider at CERN. Inclusive and differential measurements as a function of the invariant mass, transverse momentum, and longitudinal boost of the tt¯ system are performed both in the full phase space and in a fiducial phase space closely matching the detector acceptance. Two observables are studied: AℓℓC based on the selected leptons and Att¯C based on the reconstructed tt¯ final state. The inclusive asymmetries are measured in the full phase space to be AℓℓC=0.008±0.006 and Att¯C=0.021±0.016, which are in agreement with the Standard Model predictions of AℓℓC=0.0064±0.0003 and Att¯C=0.0111±0.0004