Dominant aerosol processes during high-pollution episodes over Greater Tokyo

This paper studies two high-pollution episodes over Greater Tokyo: 9 and 10 December 1999, and 31 July and 1 August 2001. Results obtained with the chemistry-transport model (CTM) Polair3D are compared to measurements of inorganic PM2.5. To understand to which extent the aerosol processes modeled in Polair3D impact simulated inorganic PM2.5, Polair3D is run with different options in the aerosol module, e.g. with/without heterogeneous reactions. To quantify the impact of processes outside the aerosol module, simulations are also done with another CTM (CMAQ). In the winter episode, sulfate is mostly impacted by condensation, coagulation, long-range transport, and deposition to a lesser extent. In the summer episode, the effect of long-range transport largely dominates. The impact of condensation/evaporation is dominant for ammonium, nitrate and chloride in both episodes. However, the impact of the thermodynamic equilibrium assumption is limited. The impact of heterogeneous reactions is large for nitrate and ammonium, and taking heterogeneous reactions into account appears to be crucial in predicting the peaks of nitrate and ammonium. The impact of deposition is the same for all inorganic PM2.5. It is small compared to the impact of other processes although it is not negligible. The impact of nucleation is negligible in the summer episode, and small in the winter episode. The impact of coagulation is larger in the winter episode than in the summer episode, because the number of small particles is higher in the winter episode as a consequence of nucleation.Comment: Journal of Geophysical Research D: Atmospheres (15/05/2007) in pres

The performance of thin NaI(Tl) scintillator plate for dark matter search

A thin (0.05cm) and wide area (5cmX5cm) NaI(Tl) scintillator was developed. The performance of the thin NaI(Tl) plate, energy resolution, single photoelectron energy and position sensitivity were tested. An excellent energy resolution of 20% (FWHM) at 60keV was obtained. The single photoelectron energy was calculated to be approximately 0.42 0.02keV. Position information in the 5cmx5cm area of the detector was also obtained by analyzing the ratio of the number of photons collected at opposite ends of the detector. The position resolution was obtained to be 1cm (FWHM) in the 5cmx5cm area.Comment: 10 pages. Accepted to Journal of Physical Society of Japa

Updating preconditioners for modified least squares problems

[EN] In this paper, we analyze how to update incomplete Cholesky preconditioners to solve least squares problems using iterative methods when the set of linear relations is updated with some new information, a new variable is added or, contrarily, some information or variable is removed from the set. Our proposed method computes a low-rank update of the preconditioner using a bordering method which is inexpensive compared with the cost of computing a new preconditioner. Moreover, the numerical experiments presented show that this strategy gives, in many cases, a better preconditioner than other choices, including the computation of a new preconditioner from scratch or reusing an existing one.Partially supported by Spanish Grants MTM2014-58159-P and MTM2015-68805-REDT.Marín Mateos-Aparicio, J.; Mas Marí, J.; Guerrero-Flores, DJ.; Hayami, K. (2017). Updating preconditioners for modified least squares problems. Numerical Algorithms. 75(2):491-508. https://doi.org/10.1007/s11075-017-0315-zS491508752Alexander, S.T., Pan, C.T., Plemmons, R.J.: Analysis of a recursive least squares hyperbolic rotation algorithm for signal processing. Linear Algebra Appl. 98, 3–40 (1988)Andrew, R., Dingle, N.: Implementing QR factorization updating algorithms on GPUs. Parallel Comput. 40(7), 161–172 (2014). doi: 10.1016/j.parco.2014.03.003 . http://www.sciencedirect.com/science/article/pii/S0167819114000337 . 7th Workshop on Parallel Matrix Algorithms and ApplicationsBenzi, M., T˚uma, M.: A robust incomplete factorization preconditioner for positive definite matrices. Numer. Linear Algebra Appl. 10(5-6), 385–400 (2003)Benzi, M., Szyld, D.B., Van Duin, A.: Orderings for incomplete factorization preconditioning of nonsymmetric problems. SIAM J. Sci. Comput. 20(5), 1652–1670 (1999)Björck, Å.: Numerical methods for Least Squares Problems. SIAM, Philadelphia (1996)Bru, R., Marín, J., Mas, J., T˚uma, M.: Preconditioned iterative methods for solving linear least squares problems. SIAM J. Sci. Comput. 36(4), A2002–A2022 (2014)Cerdán, J., Marín, J., Mas, J.: Low-rank upyears of balanced incomplete factorization preconditioners. Numer. Algorithms. doi: 10.1007/s11075-016-0151-6 (2016)Chambers, J.M.: Regression updating. J. Amer. Statist. Assoc. 66, 744–748 (1971)Davis, T.A., Hu, Y.: The university of florida sparse matrix collection. ACM trans. Math. Software 38(1), 1–25 (2011)Davis, T.A., Hager, W.W.: Modifying a sparse Cholesky factorization. SIAM J. Matrix Anal. Appl. 20, 606–627 (1999)Davis, T.A., Hager, W.W.: Multiple-rank modifications of a sparse Cholesky factorization. SIAM J. Matrix Anal. Appl. 22, 997–1013 (2001)Davis, T.A., Hager, W.W.: Row modification of a sparse Cholesky factorization. SIAM J. Matrix Anal. Appl. 26, 621–639 (2005)Hammarling, S., Lucas, C.: Updating the QR factorization and the least squares problem. Tech. rep., The University of Manchester, http://www.manchester.ac.uk/mims/eprints (2008)Olsson, O., Ivarsson, T.: Using the QR factorization to swiftly upyear least squares problems. Thesis report, Centre for Mathematical Sciences. The Faculty of Engineering at Lund University LTH (2014)Pothen, A., Fan, C.J.: Computing the block triangular form of a sparse matrix. ACM Trans. Math. Software 16, 303–324 (1990)Saad, Y.: ILUT: A dual threshold incomplete LU factorization. Numer. Linear Algebra Appl. 1(4), 387–402 (1994)Saad, Y.: Iterative Methods for Sparse Linear Systems. PWS Publishing Co., Boston (1996

Is Optimism Associated With Healthier Cardiovascular-Related Behavior? Meta-Analyses of 3 Health Behaviors

Optimistic people have reduced risk for cardiovascular disease and cardiovascular-related mortality compared with their less optimistic peers. One explanation for this is that optimistic people may be more likely to engage in healthy behavior like exercising frequently, eating fruits and vegetables, and avoiding cigarette smoking. However, researchers have not formally determined the extent or direction of optimism’s association with health behaviors. Moreover, it is unclear whether optimism temporally precedes health behaviors or whether the relationship is because of shared common causes. We conducted random effects meta-analyses examining optimism’s association with 3 health behaviors relevant for the prevention of cardiovascular disease. PubMed and PsycINFO databases were searched for studies published through November 2017 reporting on optimism’s relationship with physical activity, diet, and cigarette smoking. We identified 34 effect sizes for physical activity (n=90 845), 15 effect sizes for diet (n=47 931), and 15 effect sizes for cigarette smoking (n=15 052). Findings suggested that more optimistic individuals tended to engage in healthier behaviors compared with less optimistic individuals, but effect sizes were modest (ractivity=0.07, P\u3c0.0001; rdiet=0.12, P\u3c0.0001; and rsmoking=0.07, P=0.001). Most evidence was cross-sectional (≥53% of effect sizes) and did not consider sociodemographic characteristics (\u3c53% of effect sizes) or psychological distress (\u3c27% of effect sizes) as potential confounders. Optimism is associated with healthier behaviors that protect against cardiovascular disease, although most evidence was relatively low quality. Additional longitudinal and experimental research is required to determine whether optimism causally contributes to healthy behaviors and whether optimism could be an effective target for preventing cardiovascular disease

Partial Disorder and Metal-Insulator Transition in the Periodic Anderson Model on a Triangular Lattice

Ground state of the periodic Anderson model on a triangular lattice is systematically investigated by the mean-field approximation. We found that the model exhibits two different types of partially disordered states: one is at half filling and the other is at other commensurate fillings. In the latter case, the kinetic energy is lowered by forming an extensive network involving both magnetic and nonmagnetic sites, in sharp contrast to the former case in which the nonmagnetic sites are rather isolated. This spatially extended nature of nonmagnetic sites yields a metallic partially-disordered state by hole doping. We discuss the mechanism of the metal-insulator transition by the change of electronic structure.Comment: 4 pages, 4 figures, accepted for publication in J. Phys. Soc. Jp

WIMPs search by means of the highly segmented scintillator

The highly sensitive method to search for WIMPs dark matter particles is proposed. An array of thin NaI(Tl) plate has the great selectivity for distinguishing the WIMPs events and background ones. The principle of signal selection for WIMPs is described. The high sensitivity for SD (spin-dependent) type WIMPs is expected by applying multi-layer system of NaI(Tl) detector.Comment: 11 pages, added some sentences to make the arguments clea