203 research outputs found
Self-avoiding walks and connective constants in small-world networks
Long-distance characteristics of small-world networks have been studied by
means of self-avoiding walks (SAW's). We consider networks generated by
rewiring links in one- and two-dimensional regular lattices. The number of
SAW's was obtained from numerical simulations as a function of the number
of steps on the considered networks. The so-called connective constant,
, which characterizes the long-distance
behavior of the walks, increases continuously with disorder strength (or
rewiring probability, ). For small , one has a linear relation , and being constants dependent on the underlying
lattice. Close to one finds the behavior expected for random graphs. An
analytical approach is given to account for the results derived from numerical
simulations. Both methods yield results agreeing with each other for small ,
and differ for close to 1, because of the different connectivity
distributions resulting in both cases.Comment: 7 pages, 5 figure
A Mediterranean lifestyle reduces the risk of cardiovascular disease in the âSeguimiento Universidad de Navarraâ (SUN) cohort
Background and aims: A healthy lifestyle is essential to prevent cardiovascular disease
(CVD). However, beyond dietary habits, there is a scarcity of studies comprehensively assessing
the typical traditional Mediterranean lifestyle with a multi-dimensional index. We assessed the
association between the Mediterranean lifestyle (measured with the MEDLIFE index including
diet, physical activity, and other lifestyle factors) and the incidence of CVD.
Methods and results: The âSeguimiento Universidad de Navarraâ (SUN) project is a prospective,
dynamic and multipurpose cohort of Spanish university graduates. We calculated a MEDLIFE
score, composed of 28 items on food consumption, dietary habits, physical activity, rest, social
habits, and conviviality, for 18,631 participants by assigning 1 point for each typical Mediterra-
nean lifestyle factor achieved, for a theoretically possible final score ranging from 0 to 28 points.
During an average follow-up of 11.5 years, 172 CVD cases (myocardial infarction, stroke or cardio-
vascular death) were observed. An inverse association between the MEDLIFE score and the risk of
primary cardiovascular events was observed, with multivariable-adjusted hazard ratio
(HR) Z 0.50; (95% confidence interval, 0.31e0.81) for the highest MEDLIFE scores (14e23 points)
compared to the lowest scores (0e9 points), p (trend) Z 0.004.
Conclusion: A higher level of adherence to the Mediterranean lifestyle was significantly associ-
ated with a lower risk of CVD in a Spanish cohort. Public health strategies should promote the
Mediterranean lifestyle to preserve cardiovascular health
Planktonic Protist Diversity across Contrasting Subtropical and Subantarctic Waters of the Southwest Pacific.
Planktonic protists are an essential component of marine pelagic ecosystems where they mediate important trophic and biogeochemical functions. Although these functions are largely influenced by their taxonomic affiliation, the composition and spatial variability of planktonic protist communities remain poorly characterized in vast areas of the ocean. Here, we investigated the diversity of these communities in contrasting oceanographic conditions of the southwest Pacific (33â58 °S) using DNA metabarcoding of the 18S rRNA gene. Seawater samples collected during twelve cruises ( = 482, 0â3100 m) conducted east of New Zealand were used to characterize protist communities in Subtropical (STW) and Subantarctic (SAW) surface water masses and the Subtropical Front (STF) that separates them. Diversity decreased with increasing latitude and increasing temperature but tended to be lowest in the STF. Sample ordination resulting from the abundance of amplicon single variants (ASVs) corresponded to the different water masses. Overall, Dinoflagellata (Syndiniales, 27%; Dinophyceae, 24% of standardized number of reads) dominated the euphotic zone followed by Chlorophyta (20%), but their relative abundance and composition at class and lower taxonomic levels varied consistently between water masses. Among Chlorophyta, several picoplanktonic algae species of the Mamiellophyceae class including Ostreococcus lucimarinus dominated in STW, while the Chloropicophyceae species Chloroparvula pacifica was most abundant in SAW. Bacillariophyta (5%), Prymnesiophyceae (5%), and Pelagophyceae (2%) classes were less abundant but showed analogous water mass specificity at class and finer taxonomic levels. Protist community composition in the STF had mixed characteristics and showed regional differences with the southern STF (50 °S) having more resemblance with subantarctic communities than the STF over the Chatham Rise region (42â44 °S). Below the euphotic zone, Syndiniales sequences (40%) dominated the dataset followed by Radiolaria (31%), Dinophyceae (14%) and other heterotrophic groups like Marine Stramenopiles and ciliates (1â1.5%). Among Radiolaria, several unidentified ASVs assigned to Spumellaria were most abundant, but showed significantly different distributions between STW and SAW highlighting the need to further investigate the taxonomy and ecology of this group. The present study represents a significant step forward towards characterizing protistan communities composition in relation to major physical oceanographic features in the southwest Pacific providing new insights about the biogeography and ecological preferences of different planktonic protist taxa from class to species and genotypic level
Transfer Matrices and Partition-Function Zeros for Antiferromagnetic Potts Models. V. Further Results for the Square-Lattice Chromatic Polynomial
We derive some new structural results for the transfer matrix of
square-lattice Potts models with free and cylindrical boundary conditions. In
particular, we obtain explicit closed-form expressions for the dominant (at
large |q|) diagonal entry in the transfer matrix, for arbitrary widths m, as
the solution of a special one-dimensional polymer model. We also obtain the
large-q expansion of the bulk and surface (resp. corner) free energies for the
zero-temperature antiferromagnet (= chromatic polynomial) through order q^{-47}
(resp. q^{-46}). Finally, we compute chromatic roots for strips of widths 9 <=
m <= 12 with free boundary conditions and locate roughly the limiting curves.Comment: 111 pages (LaTeX2e). Includes tex file, three sty files, and 19
Postscript figures. Also included are Mathematica files data_CYL.m and
data_FREE.m. Many changes from version 1: new material on series expansions
and their analysis, and several proofs of previously conjectured results.
Final version to be published in J. Stat. Phy
Unfolding of differential energy spectra in the MAGIC experiment
The paper describes the different methods, used in the MAGIC experiment, to
unfold experimental energy distributions of cosmic ray particles (gamma-rays).
Questions and problems related to the unfolding are discussed. Various
procedures are proposed which can help to make the unfolding robust and
reliable. The different methods and procedures are implemented in the MAGIC
software and are used in most of the analyses.Comment: Submitted to NIM
The Mars Environmental Dynamics Analyzer, MEDA. A Suite of Environmental Sensors for the Mars 2020 Mission
86 pags., 49 figs., 24 tabs.NASAâs Mars 2020 (M2020) rover mission includes a suite of sensors to monitor current environmental conditions near the surface of Mars and to constrain bulk aerosol properties from changes in atmospheric radiation at the surface. The Mars Environmental Dynamics Analyzer (MEDA) consists of a set of meteorological sensors including wind sensor, a barometer, a relative humidity sensor, a set of 5 thermocouples to measure atmospheric temperature at âŒ1.5 m and âŒ0.5 m above the surface, a set of thermopiles to characterize the thermal IR brightness temperatures of the surface and the lower atmosphere. MEDA adds a radiation and dust sensor to monitor the optical atmospheric properties that can be used to infer bulk aerosol physical properties such as particle size distribution, non-sphericity, and concentration. The MEDA package and its scientific purpose are described in this document as well as how it responded to the calibration tests and how it helps prepare for the human exploration of Mars. A comparison is also presented to previous environmental monitoring payloads landed on Mars on the Viking, Pathfinder, Phoenix, MSL, and InSight spacecraft.This work has been funded by the Spanish Ministry of Economy and Competitiveness, through the projects No. ESP2014-54256-C4-1-R (also -2-R, -3-R and -4-R) and AYA2015-65041-P; Ministry of Science, Innovation and Universities, projects No. ESP2016-79612-C3-1-R (also -2-R and -3-R),
ESP2016-80320-C2-1-R, RTI2018-098728-B-C31 (also -C32 and -C33) and RTI2018-099825-B-C31; Instituto Nacional de TĂ©cnica Aeroespacial; Ministry of Science and Innovationâs Centre for the Development of Industrial Technology; Grupos Gobierno Vasco IT1366-19; and European Research Council Consolidator Grant no 818602. The US co-authors performed their work under sponsorship from NASAâs Mars 2020 project, from the
Game Changing Development program within the Space Technology Mission Directorate and from the Human Exploration and Operations Directorate
Systematic Review of Medicine-Related Problems in Adult Patients with Atrial Fibrillation on Direct Oral Anticoagulants
New oral anticoagulant agents continue to emerge on the market and their safety requires assessment to provide evidence of their suitability for clinical use. There-fore, we searched standard databases to summarize the English language literature on medicine-related problems (MRPs) of direct oral anticoagulants DOACs (dabigtran, rivaroxban, apixban, and edoxban) in the treatment of adults with atri-al fibrillation. Electronic databases including Medline, Embase, International Pharmaceutical Abstract (IPA), Scopus, CINAHL, the Web of Science and Cochrane were searched from 2008 through 2016 for original articles. Studies pub-lished in English reporting MRPs of DOACs in adult patients with AF were in-cluded. Seventeen studies were identified using standardized protocols, and two reviewers serially abstracted data from each article. Most articles were inconclusive on major safety end points including major bleeding. Data on major safety end points were combined with efficacy. Most studies inconsistently reported adverse drug reactions and not adverse events or medication error, and no definitions were consistent across studies. Some harmful drug effects were not assessed in studies and may have been overlooked. Little evidence is provided on MRPs of DOACs in patients with AF and, therefore, further studies are needed to establish the safety of DOACs in real-life clinical practice
Measurement of prompt D and meson azimuthal anisotropy and search for strong electric fields in PbPb collisions at root = 5.02 TeV
The strong Coulomb field created in ultrarelativistic heavy ion collisions is expected to produce a rapiditydependent difference (Av2) in the second Fourier coefficient of the azimuthal distribution (elliptic flow, v2) between D0 (uc) and D0 (uc) mesons. Motivated by the search for evidence of this field, the CMS detector at the LHC is used to perform the first measurement of Av2. The rapidity-averaged value is found to be (Av2) = 0.001 ? 0.001 (stat)? 0.003 (syst) in PbPb collisions at ?sNN = 5.02 TeV. In addition, the influence of the collision geometry is explored by measuring the D0 and D0mesons v2 and triangular flow coefficient (v3) as functions of rapidity, transverse momentum (pT), and event centrality (a measure of the overlap of the two Pb nuclei). A clear centrality dependence of prompt D0 meson v2 values is observed, while the v3 is largely independent of centrality. These trends are consistent with expectations of flow driven by the initial-state geometry. ? 2021 The Author. Published by Elsevier B.V. This is an open access article under the CC BY licens
Performance of the CMS Level-1 trigger in proton-proton collisions at âs = 13 TeV
At the start of Run 2 in 2015, the LHC delivered proton-proton collisions at a center-of-mass energy of 13\TeV. During Run 2 (years 2015â2018) the LHC eventually reached a luminosity of 2.1Ă 10 cms, almost three times that reached during Run 1 (2009â2013) and a factor of two larger than the LHC design value, leading to events with up to a mean of about 50 simultaneous inelastic proton-proton collisions per bunch crossing (pileup). The CMS Level-1 trigger was upgraded prior to 2016 to improve the selection of physics events in the challenging conditions posed by the second run of the LHC. This paper describes the performance of the CMS Level-1 trigger upgrade during the data taking period of 2016â2018. The upgraded trigger implements pattern recognition and boosted decision tree regression techniques for muon reconstruction, includes pileup subtraction for jets and energy sums, and incorporates pileup-dependent isolation requirements for electrons and tau leptons. In addition, the new trigger calculates high-level quantities such as the invariant mass of pairs of reconstructed particles. The upgrade reduces the trigger rate from background processes and improves the trigger efficiency for a wide variety of physics signals
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