61 research outputs found

    Rock magnetic techniques complemented by ferromagnetic resonance spectroscopy to analyse a sediment record

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    Environmental magnetism uses the spatial and temporal occurrence of magnetic carriers as diagnostic tools to detect environmental changes. Concentration, composition, grain size and configuration of the carriers inferred from magnetic properties are key parameters, because they are indicative of the formation conditions of magnetic phases, and/or of processes such as diagenesis and weathering. We present a detailed ferromagnetic resonance (FMR) spectroscopy analysis in concert with routinely used rock magnetic measurements to determine these parameters in a sediment record that documents the development of Lake Soppensee (Central Switzerland) since latest Pleistocene. FMR spectroscopy monitors varying concentration of the predominant magnetite/maghemite by the spectral signal intensity, whereas the stable single domain and superparamagnetic states are determined by the signal shape at room and low temperature. Fitting and simulation of FMR spectra are successfully applied to samples with well-defined magnetite components in the sediment matrix. Clear evidence for the colonization of magnetotactic bacteria (MTB) in Lake Soppensee was possible by applying empirical spectral separation to measured FMR signals that yield two magnetite populations differing in their configuration, that is, dispersed and aligned in chains. Low temperature measurements showed that these MTB can be preserved as pure or oxidized magnetite. The FMR data set confirms and completes rock magnetic information obtained from the lacustrine sedimentary record. The advanced application of FMR spectroscopy in the presented study critically highlights the benefit of this rapid and non-destructive method for future analysis of magnetic properties in environmental studie

    Health-related quality of life after colorectal cancer in England: a patient-reported outcomes study of individuals 12 to 36 months after diagnosis

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    Purpose: This population-level study was conducted to define the health-related quality of life (HRQL) of individuals living with and beyond colorectal cancer (CRC) and to identify factors associated with poor health outcomes. Patients and Methods: All individuals diagnosed with CRC in England in 2010 and 2011 who were alive 12 to 36 months after diagnosis were sent a questionnaire. This included questions related to treatment, disease status, other long-term conditions (LTCs), generic HRQL (EuroQol-5D), and cancer-specific outcomes (Functional Assessment of Cancer Therapy and Social Difficulties Inventory items). Results: The response rate was 63.3% (21,802 of 34,467 patients). One or more generic health problems were reported by 65% of respondents, with 10% of patients reporting problems in all five domains. The reporting of problems was higher than in the general population and was most marked in those age less than 55 years. Certain subgroups reported a higher number of problems, notably those with one or more other LTCs, those with active or recurrent disease, those with a stoma, and those at the extremes of the age range ( 85 years). Of respondents without a stoma, 16.3% reported no bowel control. Reversal of a stoma resulted in fewer severe bowel problems but more moderate problems than those who had never had a stoma. A quarter of rectal cancer respondents (25.1%) reported difficulties with sexual matters (compared with 11.2% of colon cancer respondents). Conclusion: This study demonstrates the success of a national patient-reported outcomes survey. The results have the potential to support system-wide improvement in health outcomes through the identification of particular challenges faced by individuals after treatment for CRC

    Combined use of magnetometry and spectroscopy for identifying magnetofossils in sediments

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    Identification of the mineral remains of magnetotactic bacteria (MTB),known as magnetofossils, is of particular interest because theiroccurrence can be used for environmental and climatic reconstructions.Single-domain magnetite particles, which are biomineralized in the cellbody of MTB, have characteristic properties that can be used to detecttheir fossil remains. Acquisition of anhysteretic and isothermalremanent magnetization (ARM and IRM), first-order reversal curve (FORC)diagrams, and ferromagnetic resonance (FMR) spectra were used to detectthe magnetic mineral inventory in Holocene lake sediments. A comparativeanalysis in terms of the discriminatory power of these methods ispresented. The FORC diagrams contain two distinct features: a sharphorizontal ridge centered on the horizontal axis B-c and a feature withsymmetric spread along the vertical B-b axis. The coercivity spectraderived from the central ridge coincides with that derived from ARM andIRM acquisition curves and is compatible with the presence ofnoninteracting linear chains of single-domain magnetite. The secondfeature on FORC diagrams is indicative of interacting particles inclusters. In the FMR spectra from bulk sediment, two populations areseparated empirically based on the FORC information. An asymmetricsignal is taken to describe the population, which contains single-domainparticles in clusters. Empirical spectral separation of thiscontribution results in FMR spectra that are similar to those of intactMTB, which strongly suggests that a fraction of linear magnetosomechains is present. Combination of FMR and FORC results demonstrates thestrong potential of these methods for identifying magnetofossils, basedon alignment and interaction patterns of magnetic particles

    Constraints on dark matter to dark radiation conversion in the late universe with DES-Y1 and external data

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    84siWe study a class of decaying dark matter models as a possible resolution to the observed discrepancies between early- and late-time probes of the universe. This class of models, dubbed DDM, characterizes the evolution of comoving dark matter density with two extra parameters. We investigate how DDM affects key cosmological observables such as the CMB temperature and matter power spectra. Combining 3x2pt data from Year 1 of the Dark Energy Survey,Planck-2018 CMB temperature and polarization data, Supernova (SN) Type Ia data from Pantheon, and BAO data from BOSS DR12, MGS and 6dFGS, we place new constraints on the amount of dark matter that has decayed and the rate with which it converts to dark radiation. The fraction of the decayed dark matter in units of the current amount of dark matter, zetazeta, is constrained at 68% confidence level to be <0.32 for DES-Y1 3x2pt data, <0.030 for CMB+SN+BAO data, and <0.037 for the combined dataset. The probability that the DES and CMB+SN+BAO datasets are concordant increases from 4% for the LambdaLambdaCDM model to 8% (less tension) for DDM. Moreover, tension in S8=sigma8sqrtOmegam/0.3S_8=sigma_8sqrt{Omega_m/0.3} between DES-Y1 3x2pt and CMB+SN+BAO is reduced from 2.3sigmasigma to 1.9sigmasigma. We find no reduction in the Hubble tension when the combined data is compared to distance-ladder measurements in the DDM model. The maximum-posterior goodness-of-fit statistics of DDM and LambdaLambdaCDM are comparable, indicating no preference for the DDM cosmology over LambdaLambdaCDM....partially_openopenChen, Angela; Huterer, Dragan; Lee, Sujeong; Ferté, Agnès; Weaverdyck, Noah; Alonso Alves, Otavio; Leonard, C. Danielle; MacCrann, Niall; Raveri, Marco; Porredon, Anna; Di Valentino, Eleonora; Muir, Jessica; Lemos, Pablo; Liddle, Andrew; Blazek, Jonathan; Campos, Andresa; Cawthon, Ross; Choi, Ami; Dodelson, Scott; Elvin-Poole, Jack; Gruen, Daniel; Ross, Ashley; Secco, Lucas F.; Sevilla, Ignacio; Sheldon, Erin; Troxel, Michael A.; Zuntz, Joe; Abbott, Tim; Aguena, Michel; Allam, Sahar; Annis, James; Avila, Santiago; Bertin, Emmanuel; Bhargava, Sunayana; Bridle, Sarah; Brooks, David; Carnero Rosell, Aurelio; Carrasco Kind, Matias; Carretero, Jorge; Costanzi, Matteo; Crocce, Martin; da Costa, Luiz; Elidaiana da Silva Pereira, Maria; Davis, Tamara; Doel, Peter; Eifler, Tim; Ferrero, Ismael; Fosalba, Pablo; Frieman, Josh; Garcia-Bellido, Juan; Gaztanaga, Enrique; Gerdes, David; Gruendl, Robert; Gschwend, Julia; Gutierrez, Gaston; Hinton, Samuel; Hollowood, Devon L.; Honscheid, Klaus; Hoyle, Ben; James, David; Jarvis, Mike; Kuehn, Kyler; Lahav, Ofer; Maia, Marcio; Marshall, Jennifer; Menanteau, Felipe; Miquel, Ramon; Morgan, Robert; Palmese, Antonella; Paz-Chinchon, Francisco; Plazas Malagón, Andrés; Roodman, Aaron; Sanchez, Eusebio; Scarpine, Vic; Schubnell, Michael; Serrano, Santiago; Smith, Mathew; Suchyta, Eric; Tarle, Gregory; Thomas, Daniel; To, Chun-Hao; Varga, Tamas Norbert; Weller, Jochen; Wilkinson, ReeseChen, Angela; Huterer, Dragan; Lee, Sujeong; Ferté, Agnès; Weaverdyck, Noah; Alonso Alves, Otavio; Leonard, C. Danielle; Maccrann, Niall; Raveri, Marco; Porredon, Anna; Di Valentino, Eleonora; Muir, Jessica; Lemos, Pablo; Liddle, Andrew; Blazek, Jonathan; Campos, Andresa; Cawthon, Ross; Choi, Ami; Dodelson, Scott; Elvin-Poole, Jack; Gruen, Daniel; Ross, Ashley; Secco, Lucas F.; Sevilla, Ignacio; Sheldon, Erin; Troxel, Michael A.; Zuntz, Joe; Abbott, Tim; Aguena, Michel; Allam, Sahar; Annis, James; Avila, Santiago; Bertin, Emmanuel; Bhargava, Sunayana; Bridle, Sarah; Brooks, David; Carnero Rosell, Aurelio; Carrasco Kind, Matias; Carretero, Jorge; Costanzi, Matteo; Crocce, Martin; da Costa, Luiz; Elidaiana da Silva Pereira, Maria; Davis, Tamara; Doel, Peter; Eifler, Tim; Ferrero, Ismael; Fosalba, Pablo; Frieman, Josh; Garcia-Bellido, Juan; Gaztanaga, Enrique; Gerdes, David; Gruendl, Robert; Gschwend, Julia; Gutierrez, Gaston; Hinton, Samuel; Hollowood, Devon L.; Honscheid, Klaus; Hoyle, Ben; James, David; Jarvis, Mike; Kuehn, Kyler; Lahav, Ofer; Maia, Marcio; Marshall, Jennifer; Menanteau, Felipe; Miquel, Ramon; Morgan, Robert; Palmese, Antonella; Paz-Chinchon, Francisco; Plazas Malagón, Andrés; Roodman, Aaron; Sanchez, Eusebio; Scarpine, Vic; Schubnell, Michael; Serrano, Santiago; Smith, Mathew; Suchyta, Eric; Tarle, Gregory; Thomas, Daniel; Chun-Hao, To; Varga, Tamas Norbert; Weller, Jochen; Wilkinson, Rees

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

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    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 W boson polarisation in ttˉt\bar{t} events from pp collisions at s\sqrt{s} = 8 TeV in the lepton + jets channel with ATLAS

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    Measurements of top-quark pair differential cross-sections in the eμe\mu channel in pppp collisions at s=13\sqrt{s} = 13 TeV using the ATLAS detector

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