Real space mapping of topological invariants using artificial neural networks

Topological invariants allow to characterize Hamiltonians, predicting the existence of topologically protected in-gap modes. Those invariants can be computed by tracing the evolution of the occupied wavefunctions under twisted boundary conditions. However, those procedures do not allow to calculate a topological invariant by evaluating the system locally, and thus require information about the wavefunctions in the whole system. Here we show that artificial neural networks can be trained to identify the topological order by evaluating a local projection of the density matrix. We demonstrate this for two different models, a 1-D topological superconductor and a 2-D quantum anomalous Hall state, both with spatially modulated parameters. Our neural network correctly identifies the different topological domains in real space, predicting the location of in-gap states. By combining a neural network with a calculation of the electronic states that uses the Kernel Polynomial Method, we show that the local evaluation of the invariant can be carried out by evaluating a local quantity, in particular for systems without translational symmetry consisting of tens of thousands of atoms. Our results show that supervised learning is an efficient methodology to characterize the local topology of a system.Comment: 9 pages, 6 figure

Chiropractic student diagnosis and management of headache disorders: A survey examining self-perceived preparedness and clinical proficiency.

ObjectiveTo explore the self-perceived preparedness and clinical proficiency in headache diagnosis and management of Australian chiropractic students in senior years of study.MethodsAustralian chiropractic students in the 4th (n = 134) and 5th year (n = 122) of 2 chiropractic university programs were invited to participate in an online cross-sectional survey. Descriptive analyses were conducted for all variables. Post hoc analyses were performed using simple linear regression to evaluate the relationship between self-perceived preparedness and correctness of headache diagnosis and management scores.ResultsAustralian chiropractic students in senior years demonstrated moderate overall levels of self-perceived preparedness and proficiency in their ability to diagnose and manage headache disorders. Final-year students had a slightly higher self-perceived preparedness and proficiency in headache diagnosis and management compared to those students in the 4th year of study. There was no relationship between self-perceived preparedness and correctness of headache diagnosis and management for either 4th- or 5th-year chiropractic students.ConclusionOur findings suggest that there may be gaps in graduate chiropractic student confidence and proficiency in headache diagnosis and management. These findings call for further research to explore graduate chiropractic student preparedness and proficiency in the diagnosis and management of headache disorders

Epidural administration of ropivacaine and its effects on the pharmacodynamics of rocuronium: Randomized controlled trial. Interaction between ropivacaine and rocuronium

Potentiation of neuromuscular blocking agents by local anesthetics has been described in various clinical and experimental studies. This study assessed the influence of epidural ropivacaine on pharmacodynamic characteristics of rocuronium.Design: This was a prospective randomized clinical trial at the women's hospital, an university tertiary hospital in Brazil. Sixty-two patients underwent elective abdominal surgeries requiring general anesthesia.Intervention: Patients were distributed into two groups: Group 1 (general anesthesia and epidural anesthesia) and Group 2 (general anesthesia). In Group 1, 0.2% ropivacaine at a dose of 40 mg (20 ml) was associated with 2 mg (2 ml) of morphine in a single epidural injection. The following parameters were assessed: clinical duration (DC25) and time for recovery of the train-of-four (TOF) 0.9 ratio (T4/T1 = 90%) after an initial 0.6 mg/kg dose of rocuronium. The primary outcomes were DC25and TOF 0.9 ratio (T4/T1 = 90%). Secondary outcomes were total propofol and remifentanil consumption.Results: Values were presented as median and interquartile range. The results for DC25and TOF 0.9 of rocuronium were, respectively, 41.5 35.0-55.0 (25.0-63.0) in Group 1 and 44.0 37.0-51.0 (20.0-67.0) in Group 2 (P = 0.88); 88.0 67.0-99.0 (43.0-137.0) in Group 1; and 80.0 71.0-86.0 (38.0-155.0) in Group 2 (P = 0.83). There was no significant difference between the groups, in terms of pharmacodynamic characteristics of rocuronium. Propofol consumption did not show any difference between the groups. However, remifentanil consumption was significantly lower in Group 1 (P < 0.01).Conclusion: Epidural ropivacaine, in the dose studied, did not prolong the duration of rocuronium-induced neuromuscular blockade.Trial Registry Number: ReBEC (ref: RBR-7cyp6t)141636

Geometric reconstruction methods for electron tomography

Electron tomography is becoming an increasingly important tool in materials science for studying the three-dimensional morphologies and chemical compositions of nanostructures. The image quality obtained by many current algorithms is seriously affected by the problems of missing wedge artefacts and nonlinear projection intensities due to diffraction effects. The former refers to the fact that data cannot be acquired over the full $180^\circ$ tilt range; the latter implies that for some orientations, crystalline structures can show strong contrast changes. To overcome these problems we introduce and discuss several algorithms from the mathematical fields of geometric and discrete tomography. The algorithms incorporate geometric prior knowledge (mainly convexity and homogeneity), which also in principle considerably reduces the number of tilt angles required. Results are discussed for the reconstruction of an InAs nanowire

Feeding spectra and activity of the freshwater crab Trichodactylus kensleyi (Decapoda: Brachyura: Trichodactylidae) at La Plata basin

Background: In inland water systems, it is important to characterize the trophic links in order to identify the ‘trophic species’ and, from the studies of functional diversity, understand the dynamics of matter and energy in these environments. The aim of this study is to analyze the natural diet of Trichodactylus kensleyi of subtropical rainforest streams and corroborate the temporal variation in the trophic activity during day hours. Results: A total of 15 major taxonomic groups were recognized in gut contents. The index of relative importance identified the following main prey items in decreasing order of importance: vegetal remains, oligochaetes, chironomid larvae, and algae. A significant difference was found in the amount of full stomachs during day hours showing a less trophic activity at midday and afternoon. The index of relative importance values evidenced the consumption of different prey according to day moments. Results of the gut content indicate that T. kensleyi is an omnivorous crab like other trichodactylid species. Opportunistic behavior is revealed by the ingestion of organisms abundant in streams such as oligochaetes and chironomid larvae. The consumption of allochthonous plant debris shows the importance of this crab as shredder in subtropical streams. However, the effective assimilation of plant matter is yet unknown in trichodactylid crabs. Conclusions: This research provides knowledge that complements previous studies about trophic relationships of trichodactylid crabs and supported the importance of T. kensleyi in the transference of energy and matter from benthic community and riparian sources to superior trophic levels using both macro- and microfauna.Fil: Williner, Verónica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias; ArgentinaFil: de Azevedo Carvalho, Debora. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Collins, Pablo Agustin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; Argentin

Effectiveness and safety of obeticholic acid in a Southern European multicenter cohort of patients with primary biliary cholangitis and suboptimal response to ursodeoxycholic acid

Background Obeticholic acid (OCA) was recently approved as the only on-label alternative for patients with primary biliary cholangitis (PBC) with intolerance or suboptimal response to ursodeoxycholic acid (UDCA). However, few data are available outside clinical trials. Aim To assess the effectiveness and safety of OCA in a real-world cohort of patients with non-effective UDCA therapy. Methods Open-label, prospective, real-world, multicentre study, enrolling consecutive patients who did not meet Paris II criteria, from 18 institutions in Spain and Portugal. Effectiveness was assessed by the changes in GLOBE and UK-PBC scores from baseline. POISE and Paris II criteria were evaluated after 12 months of OCA . Liver fibrosis was evaluated by FIB-4 and AST to platelet ratio index (APRI). Results One hundred and twenty patients were eligible, median time since PBC diagnosis 9.3 (4.0-13.8) years, 21.7% had cirrhosis, and 26.7% received had previous or concomitant treatment with fibrates. Seventy-eight patients completed at least 1 year of OCA. The Globe-PBC score decreased to 0.17 (95% CI 0.05 to 0.28; P = 0.005) and the UK-PBC score decreased to 0.81 (95% CI -0.19 to 1.80; P = 0.11). There was a significant decrease in alkaline phosphatase of 81.3 U/L (95% CI 42.5 to 120; P < 0.001), ALT 22.1 U/L (95% CI 10.4 to 33.8; P < 0.001) and bilirubin 0.12 mg/dL (95% CI 0 to 0.24; P = 0.044). FIB-4 and APRI remained stable. According to the POISE criteria, 29.5% (23 out of 78) achieved response. The adverse events rate was 35%; 11.67% discontinued (8.3% due to pruritus). Conclusions This study supports data from phase III trials with significant improvement of PBC-Globe continuous prognostic marker score among OCA-treated patients with good tolerability

Long-finned pilot whale population diversity and structure in Atlantic waters assessed through biogeochemical and genetic markers

Acknowledgements. Cetacean samples were collected under the auspices of stranding monitoring programs run by the Sociedade Portuguesa de Vida Selvagem, the Coordinadora para o Estudio dos Mamíferos Mariños (supported by the regional government Xunta de Galicia), the UK Cetacean Strandings Investigation Programme and the Scottish Agriculture College Veterinary Science Division (jointly funded by Defra and the Devolved Governments of Scotland and Wales), the Marine Mammals Research Group of the Institute of Marine Research (Norway), the Museum of Natural History of the Faroe Islands and the International Fund for Animal Welfare Marine Mammal Rescue and Research Program (USA). The authors thank all the members of these institutions and organizations for their assistance with data and sample collection. S.S.M., P.M.F. and M.F. were supported by PhD grants from the Fundação para a Ciência e Tecnologia (POPH/FSE ref SFRH/BD/ 38735/ 2007, SFRH/BD/36766/2007 and SFRH/BD/30240/ 2006, respectively). A.L. was supported by a postdoctoral grant from the Fundação para a Ciência e Tecnologia (ref SFRH/BPD/82407/2011). The work related to strandings and tissue collection in Portugal was partially supported by the SafeSea project EEAGrants PT 0039 (supported by Iceland, Liechtenstein and Norway through the EEA Financial Mechanism), the MarPro project Life09 NAT/PT/000038 (funded by the European Union program LIFE+) and the project CetSenti FCT RECI/AAG-GLO/0470/2012 (FCOMP- 01-0124-FEDER-027472) (funded by the program COMPETE and the Fundação para a Ciência e Tecnologia). G.J.P. thanks the University of Aveiro and Caixa Geral de Depósitos (Portugal) for financial support. The authors acknowledge the assistance of the chemical analysts at Marine Scotland Science with the fatty acid analysis.Peer reviewedPostprintPublisher PD

Integration of miRNA and mRNA expression profles reveals microRNA-regulated networks during muscle wasting in cardiac cachexia

Cardiac cachexia (CC) is a common complication of heart failure (HF) associated with muscle wasting and poor patient prognosis. Although different mechanisms have been proposed to explain muscle wasting during CC, its pathogenesis is still not understood. Here, we described an integrative analysis between miRNA and mRNA expression profiles of muscle wasting during CC. Global gene expression profiling identified 1,281 genes and 19 miRNAs differentially expressed in muscle wasting during CC. Several of these deregulated genes are known or putative targets of the altered miRNAs, including miR-29a-3p, miR-29b-3p, miR-210-5p, miR-214, and miR-489. Gene ontology analysis on integrative mRNA/miRNA expression profiling data revealed miRNA interactions affecting genes that regulate extra-cellular matrix (ECM) organization, proteasome protein degradation, citric acid cycle and respiratory electron transport. We further identified 11 miRNAs, including miR-29a-3p and miR-29b-3p, which target 21 transcripts encoding the collagen proteins related to ECM organization. Integrative miRNA and mRNA global expression data allowed us to identify miRNA target genes involved in skeletal muscle wasting in CC. Our functional experiments in C2C12 cells confirmed that miR-29b down-regulates collagen genes and contributes to muscle cell atrophy. Collectively, our results suggest that key ECM-associated miRNAs and their target genes may contribute to CC in HF

Distributional and reproductive aspects of the bigeye thresher shark (Alopias superciliosus) in the Atlantic ocean

Captura asociada a la pesquería de palangre de superficie dirigida a pez espadaThe bigeye thresher shark, Alopias supercilious is sometimes caught as bycatch in pelagic longline fisheries targeting tunas and swordfish in the Atlantic Ocean. As part of an ongoing cooperative program for fisheries and biological data collection, fishery observer data from various fishing nations and projects were compiled and analyzed. Those data sets include information on geographic location of the observations, as well as size, sex and in some cases maturity stage. A total of 4371 bigeye threshers were recorded throughout the Atlantic Ocean between 1992 and 2013, with the sizes ranging from 70 to 305 cm FL (fork length). Considerable variability was observed in the catchat- size, with particular emphasis on the tropical region where the mean sizes tended to be smaller than in the other regions. The expected distribution of juvenile and adult specimens also showed considerable variability, and the sex-ratios varied between regions and size classes. Maturity ogives were fitted to data from 642 specimens, with the median sizes at maturity estimated at 208.6 cm FL (corresponding to 349.1 cm TL) for females and 159.2 cm FL (corresponding to 269.8 cm TL) for males. In addition, a segmented regression model (SRM) was used for males, and two breakpoints (Bk1: 122.5cm FL, Bk2: 173.3cm FL) estimated, identifying transitions between the three different maturity stages for male sharks (immature, maturing and mature). Only a few pregnant females were recorded, always with the presence of two embryos (one per uterus), and were distributed predominantly in the tropical northeast Atlantic closer the African continent, and in the southwest region, with those regions possibly serving as nursery areas for this species. These reproductive parameters, and especially the estimated median sizes at maturity and low fecundity, highlight the vulnerability of this species, reinforcing that the bigeye thresher tends to mature at a larger size than the other species of the Alopiidae family. The biological and distributional patterns presented can help managers adopt more informed and efficient conservation measures for this species.En prensa0,000