Spectral and localization properties of random bipartite graphs

Bipartite graphs are often found to represent the connectivity between the components of many systems such as ecosystems. A bipartite graph is a set of $n$ nodes that is decomposed into two disjoint subsets, having $m$ and $n-m$ vertices each, such that there are no adjacent vertices within the same set. The connectivity between both sets, which is the relevant quantity in terms of connections, can be quantified by a parameter $\alpha\in[0,1]$ that equals the ratio of existent adjacent pairs over the total number of possible adjacent pairs. Here, we study the spectral and localization properties of such random bipartite graphs. Specifically, within a Random Matrix Theory (RMT) approach, we identify a scaling parameter $\xi\equiv\xi(n,m,\alpha)$ that fixes the localization properties of the eigenvectors of the adjacency matrices of random bipartite graphs. We also show that, when $\xi10$) the eigenvectors are localized (extended), whereas the localization--to--delocalization transition occurs in the interval $1/10<\xi<10$. Finally, given the potential applications of our findings, we round off the study by demonstrating that for fixed $\xi$, the spectral properties of our graph model are also universal.Comment: 17 pages, 10 figure

Maerl grounds : habitats of high biodiversity in European seas

The BIOMAERL programme is a 3-year collaborative programme between laboratories in UK, Spain, France and Malta which began in February 1996. Its main plans are described in the workplan. A full inventory of the biological composition (biodiversity) of maerl bed assemblages in these regions therefore has yet to be completed, but progress is outlined below.peer-reviewe

The Boston Puerto Rican Health Study, a longitudinal cohort study on health disparities in Puerto Rican adults: challenges and opportunities

BACKGROUND: The Boston Puerto Rican Health Study is an ongoing longitudinal cohort study designed to examine the role of psychosocial stress on presence and development of allostatic load and health outcomes in Puerto Ricans, and potential modification by nutritional status, genetic variation, and social support. METHODS: Self-identified Puerto Ricans, aged 45-75 years and residing in the Boston, MA metro area, were recruited through door-to-door enumeration and community approaches. Participants completed a comprehensive set of questionnaires and tests. Blood, urine and salivary samples were extracted for biomarker and genetic analysis. Measurements are repeated at a two-year follow-up. RESULTS: A total of 1500 eligible participants completed baseline measurements, with nearly 80% two-year follow-up retention. The majority of the cohort is female (70%), and many have less than 8th grade education (48%), and fall below the poverty level (59%). Baseline prevalence of health conditions is high for this age range: considerable physical (26%) and cognitive (7%) impairment, obesity (57%), type 2 diabetes (40%), hypertension (69%), arthritis (50%) and depressive symptomatology (60%). CONCLUSIONS: The enrollment of minority groups presents unique challenges. This report highlights approaches to working with difficult to reach populations, and describes some of the health issues and needs of Puerto Rican older adults. These results may inform future studies and interventions aiming to improve the health of this and similar communities

A serological assay to detect SARS-CoV-2 seroconversion in humans

Development of an enzyme-linked immunosorbent assay to detect antibodies to the SARS-CoV-2 spike protein in human sera and plasma. Here, we describe a serological enzyme-linked immunosorbent assay for the screening and identification of human SARS-CoV-2 seroconverters. This assay does not require the handling of infectious virus, can be adjusted to detect different antibody types in serum and plasma and is amenable to scaling. Serological assays are of critical importance to help define previous exposure to SARS-CoV-2 in populations, identify highly reactive human donors for convalescent plasma therapy and investigate correlates of protection.Peer reviewe

Determination of the optical depth of a DI diesel spray

The optical depth is responsible of limiting the optical diagnostic using visible wavelength in the sprays. This paper proposes to measure the optical depth directly in a real Diesel spray through line-of-sight laser extinction measurements. This easily reproducible method which does not require expensive or complex optical techniques is detailed and the measurement procedure is presented in this paper. As diesel sprays are mostly optically thick, the measurements in the denser region are not reliable and a fuel concentration model has been used to derive the results to the entire spray. This work provides values of SMD at different distance from the nozzle tip depending on the specific parameters like injection pressure or discharge density. The values extracted from a combined experimental/computational approach have been compared to PDPA measurements under the same testing conditions. The results have shown that the maximum optical depth was higher than 10 and that an increase of the injection pressure led to higher ¿ values. The SMD values appeared to be below the results measured by the PDPA and the droplet diameter showed to be the main responsible of the optical depth of the jet under the tested conditions. © 2011 The Korean Society of Mechanical Engineers and Springer-Verlag Berlin Heidelberg.Payri González, F.; Pastor, JV.; Payri, R.; Manin, JL. (2011). Determination of the optical depth of a DI diesel spray. Journal of Mechanical Science and Technology. 25(1):209-219. https://doi.org/10.1007/s12206-010-1024-xS209219251L. Pickett and D. Siebers, Non-sooting, low flame temperature mixing-controlled DI diesel combustion, SAE Paper, 2004-01-1399 (2004).S. Cheng, A. Upatnieks and C. J. Mueller, Investigation of fuel effects on dilute, mixing-controlled combustion in an optical direct-injection diesel engine, Energy & Fuels, 21 (2007) 1989–2002.S. Park, H. Kim and B. Choi, Emission characteristics of exhaust gases and nanoparticles from a diesel engine with biodiesel-diesel blended fuel (BD20), J. Mech. Sci. Technol., 23(9) (2009) 2555–2564.J. Benajes, S. Molina, K. De Rudder and T. Rente, Influence of injection rate shaping on combustion and emissions for a medium duty diesel engine, J. Mech. Sci. Technol., 20(9) (2006) 1436–1448.S. Som, S. K. Aggarwal, E. M. El-Hannouny, D. E. Longman, Investigation of Nozzle Flow and Cavitation Characteristics in a Diesel Injector, J. of Eng. Gas Turb. and Power, 132(4) (2010).J. Lee and K. Min, Effects of needle response on spray characteristics in high pressure injector driven by piezo actuator for common-rail injection system, J. Mech. Sci. Technol., 19(5) (2005) 1194–1205.R. Payri, F. J. Salvador, J. Gimeno and V. Soare, Determination of diesel sprays characteristics in real engine in-cylinder air density and pressure conditions, J. Mech. Sci. Technol., 19 (2005) 2040–2052.Y. Yue, C. F. Powell, R. Poola and J. Wang, Quantitative measurements of diesel fuel spray characteristics in the near-nozzle region by using x-ray absorption, Atomization Sprays, 11(4) (2001).M. Linne, M. Paciaroni, T. Hall and T. Parker, Ballistic imaging of the near field in a diesel spray, Experiments in Fluid,s 40(6) (2006) 836–846.H. E. Albrecht, N. Damaschke, M. Borys and C. Tropea, Laser Doppler and Phase Doppler Measurement Techniques, Springer Berlin (2003).R. Domann and Y. Hardalupas, Quantitative Measurement of planar Droplet Sauter Mean Diameter in sprays using Planar Droplet Sizing, 11th Int. Symp. on App. of Laser Techniques to Fluid Mechanics (Lisbon Portugal) (2002).M. Van der Mark, M. Van Albada and A. Lagendijk, Light scattering in strongly scattering media: Multiple scattering and weak localization, Physical Review, B 37(7) (1988).L. Araneo and R. Payri, Experimental quantification of the planar droplet sizing technique error for micro-metric monodispersed spherical particles, Proc. of the Inst. for Liquid Atomization and Spray Systems Conf. (Como Italy) (2008).G. Hiromi, Multiple scattering correction in the measurement of particle size and number density by the diffraction method, Applied Optics 25(19) (1986) 3552–3558.C. Dumouchel, P. Yongyingsakthavorn and J. Cousin, Light multiple scattering correction of laser-diffraction spray drop-size distribution measurements, International Journal of Multiphase Flow 35(3) (2009) 277–287.J. V. Pastor, R. Payri, L. Araneo and J. Manin, Correction method for droplet sizing by laser-induced fluorescence in a controlled test situation, Optical Engineering, 48(1) (2009).C. Espey and J. E. Dec, The effect of TDC temperature and density on the liquid-phase fuel penetration in a Di Diesel engine, SAE transactions, 104(4) (1995) 1400–1414.J. M. Desantes, R. Payri, A. García and J. Manin, Experimental Study of Biodiesel Blends’ Effects on Diesel Injection Processes, Energy & Fuels, 23 (2009) 3227–3235.C. R. Kitchin, Stars, Nebulae and the Interstellar Medium: Observational Physics and Astrophysics CRC Press (1987).M. A. Linne, Spectroscopic Measurement: An Introduction to the Fundamentals, Academic Press (London, UK) (2002).J. V. Pastor, J. J. Lopez, J. E. Juliá and J. V. Benajes, Planar laser-induced fluorescence fuel concentration measurements in isothermal sprays, Opt. Express, 10(7) (2002) 309–323.J. Benajes, R. Payri, S. Molina, A.H. Plazas, Investigation of the influence of injection rate shaping on the spray characteristics in a diesel common rail system equipped with a piston amplifier, Journal of fluids engineering-transactions of the ASME, 127(6) (2005) 1102–1110.V. Bermudez, R. Payri, F. J. Salvador and A. H. Plazas, Study of the influence of nozzle seat type on injection rate and spray behavior, ImechE, Journal of automobile engineering, Part D, 219 (2005) 677–689.R. Payri, J. M. Garcia, F. J. Salvador and J. Gimeno, Using spray momentum flux measurements to understand the influence of diesel nozzle geometry on spray characteristics, Fuel, 84 (2005) 551–561.J. M. Desantes, R. Payri, F. J. Salvador and A. Gil, Development and validation of a theoretical model for diesel spray penetration, Fuel, 85 (2006) 910–917.H. Hattori, K. Narumiya, M. Tsue and T. Kadota, Analysis of initial breakup mechanism of diesel spray injected into high-pressure ambience, SAE Paper, 2004-01-0528 (2004).J. D. J. Ingle and S. R. Crouch, Spectrochemical Analysis, Prentice Hall (New Jersey, USA) (1988).F. V. Tinaut, A. Melgar, F. Castro, M. L. Sanchez and B. A. Gimenez, Method to determine liquid concentration in nonstationary axisymmetric sprays, Experiments in Fluids, 23 (1997) 299–305.P. Laven, Simulation of Rainbows, Coronas and Glories by the use of Mie theory, Applied Optics 43(3) (2003) 436–444.J. M. Desantes, R. Payri, J. M. Garcia and F. J. Salvador, A contribution to the understanding of isothermal diesel spray dynamics, Fuel, 86(7–8) (2007) 1093–1101.R. Payri, L. Araneo, J. Shakal and V. Soare, Phase doppler measurements: system set-up optimization for characterization of a diesel nozzle, J. Mech. Sci. Technol., 22 (2008) 1620–1632.E. Berrocal, D. L. Sedarsky, M. E. Paciaroni, I. V. Meglinski and M. A. Linne, Laser light scattering in turbid media Part I: Experimental and simulated results for the spatial intensity distribution, Optics Express, 15 (2007) 10649–10665.C. Roze, T. Girasole, L. Mevcs, G. Grehan, L. Hespel and A. Delfour, Interaction between ultra short pulses and a dense scattering medium by Monte Carlo simulation: consideration of particle size effect, Optics Communications, 220(4–6) (2003) 237–245.E. Berrocal, D. L. Sedarsky, M. E. Paciaroni, I. V. Meglinski and M. A. Linne, Laser light scattering in turbid media Part II: Spatial and temporal analysis of individual scattering orders via Monte Carlo simulation, Optics Express, 17 (2009) 13792–13809.E. Berrocal, Multiple scattering of light in optical diagnostics of dense sprays and other complex turbid media, PhD Thesis Cranfield University (2006).J. Naber and D. Siebers, Effects of gas density and vaporization on penetration and dispersion of diesel sprays, SAE Paper, 960034 (1996).V. Soare, Phase Doppler Measurements in Diesel Dense Sprays: Optimisation of Measurements and Study of the Orifice Geometry Influence over the Spray at Microscopic Level PhD Thesis, Universidad Politécnica de Valencia, (2007).G. Wigley, Measurement techniques and data analyses for direct injection fuel sprays, in Phase Doppler measurements in Ultra-dense sprays, University of Darmstad (2005).J. Koo and J. Kim, Assessment of a Phase Doppler Anemometry Technique in Dense Droplet Laden Jet, KSME International Journal, 17(7) (2003) 1083–1094.J. S. Kim and J. S. Kim, A characterization of the spray evolution by dual-mode phase doppler anemometry in an injector of liquid-propellant thruster, J. Mech. Sci. Technol., 23(6) (2009) 1637–1649.J. Labs and T.E. Parker, Two-dimensional droplet size and volume fraction distributions from the near-injector region of high-pressure diesel sprays, Atomization & Sprays, 16 (2006) 843–855

A Comprehensive Microarray-Based DNA Methylation Study of 367 Hematological Neoplasms

Background: Alterations in the DNA methylation pattern are a hallmark of leukemias and lymphomas. However, most epigenetic studies in hematologic neoplasms (HNs) have focused either on the analysis of few candidate genes or many genes and few HN entities, and comprehensive studies are required. Methodology/Principal Findings: Here, we report for the first time a microarray-based DNA methylation study of 767 genes in 367 HNs diagnosed with 16 of the most representative B-cell (n = 203), T-cell (n = 30), and myeloid (n = 134) neoplasias, as well as 37 samples from different cell types of the hematopoietic system. Using appropriate controls of B-, T-, or myeloid cellular origin, we identified a total of 220 genes hypermethylated in at least one HN entity. In general, promoter hypermethylation was more frequent in lymphoid malignancies than in myeloid malignancies, being germinal center mature B-cell lymphomas as well as B and T precursor lymphoid neoplasias those entities with highest frequency of gene-associated DNA hypermethylation. We also observed a significant correlation between the number of hypermethylated and hypomethylated genes in several mature B-cell neoplasias, but not in precursor B- and T-cell leukemias. Most of the genes becoming hypermethylated contained promoters with high CpG content, and a significant fraction of them are targets of the polycomb repressor complex. Interestingly, T-cell prolymphocytic leukemias show low levels of DNA hypermethylation and a comparatively large number of hypomethylated genes, many of them showing an increased gene expression. Conclusions/Significance: We have characterized the DNA methylation profile of a wide range of different HNs entities. As well as identifying genes showing aberrant DNA methylation in certain HN subtypes, we also detected six genes DBC1, DIO3, FZD9, HS3ST2, MOS, and MYOD1 that were significantly hypermethylated in B-cell, T-cell, and myeloid malignancies. These might therefore play an important role in the development of different HNs

Association of Candidate Gene Polymorphisms With Chronic Kidney Disease: Results of a Case-Control Analysis in the Nefrona Cohort

Chronic kidney disease (CKD) is a major risk factor for end-stage renal disease, cardiovascular disease and premature death. Despite classical clinical risk factors for CKD and some genetic risk factors have been identified, the residual risk observed in prediction models is still high. Therefore, new risk factors need to be identified in order to better predict the risk of CKD in the population. Here, we analyzed the genetic association of 79 SNPs of proteins associated with mineral metabolism disturbances with CKD in a cohort that includes 2, 445 CKD cases and 559 controls. Genotyping was performed with matrix assisted laser desorption ionizationtime of flight mass spectrometry. We used logistic regression models considering different genetic inheritance models to assess the association of the SNPs with the prevalence of CKD, adjusting for known risk factors. Eight SNPs (rs1126616, rs35068180, rs2238135, rs1800247, rs385564, rs4236, rs2248359, and rs1564858) were associated with CKD even after adjusting by sex, age and race. A model containing five of these SNPs (rs1126616, rs35068180, rs1800247, rs4236, and rs2248359), diabetes and hypertension showed better performance than models considering only clinical risk factors, significantly increasing the area under the curve of the model without polymorphisms. Furthermore, one of the SNPs (the rs2248359) showed an interaction with hypertension, being the risk genotype affecting only hypertensive patients. We conclude that 5 SNPs related to proteins implicated in mineral metabolism disturbances (Osteopontin, osteocalcin, matrix gla protein, matrix metalloprotease 3 and 24 hydroxylase) are associated to an increased risk of suffering CKD

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

Multiple star systems in the Orion nebula

This is the author accepted manuscript. The final fersion is available from EDP Sciences via the DOI in this record.This work presents an interferometric study of the massive-binary fraction in the Orion Trapezium cluster with the recently comissioned GRAVITY instrument. We observed a total of 16 stars of mainly OB spectral type. We find three previously unknown companions for θ1 Ori B, θ2 Ori B, and θ2 Ori C. We determined a separation for the previously suspected companion of NU Ori. We confirm four companions for θ1 Ori A, θ1 Ori C, θ1 Ori D, and θ2 Ori A, all with substantially improved astrometry and photometric mass estimates. We refined the orbit of the eccentric high-mass binary θ1 Ori C and we are able to derive a new orbit for θ1 Ori D. We find a system mass of 21.7 M⊙ and a period of 53 days. Together with other previously detected companions seen in spectroscopy or direct imaging, eleven of the 16 high-mass stars are multiple systems. We obtain a total number of 22 companions with separations up to 600 AU. The companion fraction of the early B and O stars in our sample is about two, significantly higher than in earlier studies of mostly OB associations. The separation distribution hints toward a bimodality. Such a bimodality has been previously found in A stars, but rarely in OB binaries, which up to this point have been assumed to be mostly compact with a tail of wider companions. We also do not find a substantial population of equal-mass binaries. The observed distribution of mass ratios declines steeply with mass, and like the direct star counts, indicates that our companions follow a standard power law initial mass function. Again, this is in contrast to earlier findings of flat mass ratio distributions in OB associations. We excluded collision as a dominant formation mechanism but find no clear preference for core accretion or competitive accretion.Marie Skłodowska-Curie Grant AgreementFCT-PortugalERC Starting Gran