Browsing by Author "Zhang, Z"

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    Attrition in heterogeneous cohorts
    (Demographic Research, 2010-11-10) Vaupel, JW; Zhang, Z
    In a heterogeneous cohort, the change with age in the force of mortality or some other kind of hazard or intensity of attrition depends on how the hazard changes with age for the individuals in the cohort and on how the composition of the cohort changes due to the loss of those most vulnerable to attrition. Here we prove that the change with age for the cohort equals the average of the change in the hazard for the individuals in the cohort minus the variance in the hazard across individuals. The variance captures the compositional change. This very general and remarkably elegant relationship can be applied to understand and to analyze changes with age in many kinds of demographic hazards, including, e.g., the lifetable aging rate or the intensity of first births. © 2010 James W. Vaupel & Zhen Zhang.
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    Dark Energy Survey Year 1 Results: Cosmological Constraints from Cluster Abundances and Weak Lensing
    Abbott, TMC; Aguena, M; Alarcon, A; Allam, S; Allen, S; Annis, J; Avila, S; Bacon, D; Bechtol, K; Bermeo, A; Bernstein, GM; Bertin, E; Bhargava, S; Bocquet, S; Brooks, D; Brout, D; Buckley-Geer, E; Burke, DL; Carnero Rosell, A; Carrasco Kind, M; Carretero, J; Castander, FJ; Cawthon, R; Chang, C; Chen, X; Choi, A; Costanzi, M; Crocce, M; da Costa, LN; Davis, TM; De Vicente, J; DeRose, J; Desai, S; Diehl, HT; Dietrich, JP; Dodelson, S; Doel, P; Drlica-Wagner, A; Eckert, K; Eifler, TF; Elvin-Poole, J; Estrada, J; Everett, S; Evrard, AE; Farahi, A; Ferrero, I; Flaugher, B; Fosalba, P; Frieman, J; García-Bellido, J; Gatti, M; Gaztanaga, E; Gerdes, DW; Giannantonio, T; Giles, P; Grandis, S; Gruen, D; Gruendl, RA; Gschwend, J; Gutierrez, G; Hartley, WG; Hinton, SR; Hollowood, DL; Honscheid, K; Hoyle, B; Huterer, D; James, DJ; Jarvis, M; Jeltema, T; Johnson, MWG; Johnson, MD; Kent, S; Krause, E; Kron, R; Kuehn, K; Kuropatkin, N; Lahav, O; Li, TS; Lidman, C; Lima, M; Lin, H; MacCrann, N; Maia, MAG; Mantz, A; Marshall, JL; Martini, P; Mayers, J; Melchior, P; Mena-Fernández, J; Menanteau, F; Miquel, R; Mohr, JJ; Nichol, RC; Nord, B; Ogando, RLC; Palmese, A; Paz-Chinchón, F; Plazas, AA; Prat, J; Rau, MM; Romer, AK; Roodman, A; Rooney, P; Rozo, E; Rykoff, ES; Sako, M; Samuroff, S; Sánchez, C; Sanchez, E; Saro, A; Scarpine, V; Schubnell, M; Scolnic, D; Serrano, S; Sevilla-Noarbe, I; Sheldon, E; Smith, J Allyn; Smith, M; Suchyta, E; Swanson, MEC; Tarle, G; Thomas, D; To, C; Troxel, MA; Tucker, DL; Varga, TN; von der Linden, A; Walker, AR; Wechsler, RH; Weller, J; Wilkinson, RD; Wu, H; Yanny, B; Zhang, Y; Zhang, Z; Zuntz, J; Collaboration, DES
    We perform a joint analysis of the counts and weak lensing signal of redMaPPer clusters selected from the Dark Energy Survey (DES) Year 1 dataset. Our analysis uses the same shear and source photometric redshifts estimates as were used in the DES combined probes analysis. Our analysis results in surprisingly low values for $S_8 =\sigma_8(\Omega_{\rm m}/0.3)^{0.5}= 0.65\pm 0.04$, driven by a low matter density parameter, $\Omega_{\rm m}=0.179^{+0.031}_{-0.038}$, with $\sigma_8-\Omega_{\rm m}$ posteriors in $2.4\sigma$ tension with the DES Y1 3x2pt results, and in $5.6\sigma$ with the Planck CMB analysis. These results include the impact of post-unblinding changes to the analysis, which did not improve the level of consistency with other data sets compared to the results obtained at the unblinding. The fact that multiple cosmological probes (supernovae, baryon acoustic oscillations, cosmic shear, galaxy clustering and CMB anisotropies), and other galaxy cluster analyses all favor significantly higher matter densities suggests the presence of systematic errors in the data or an incomplete modeling of the relevant physics. Cross checks with X-ray and microwave data, as well as independent constraints on the observable--mass relation from SZ selected clusters, suggest that the discrepancy resides in our modeling of the weak lensing signal rather than the cluster abundance. Repeating our analysis using a higher richness threshold ($\lambda \ge 30$) significantly reduces the tension with other probes, and points to one or more richness-dependent effects not captured by our model.
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    Derivation of a continuum model and the energy law for moving contact lines with insoluble surfactants
    (Physics of Fluids, 2014-06-05) Zhang, Z; Xu, S; Ren, W
    A continuous model is derived for the dynamics of two immiscible fluids with moving contact lines and insoluble surfactants based on thermodynamic principles. The continuum model consists of the Navier-Stokes equations for the dynamics of the two fluids and a convection-diffusion equation for the evolution of the surfactant on the fluid interface. The interface condition, the boundary condition for the slip velocity, and the condition for the dynamic contact angle are derived from the consideration of energy dissipations. Different types of energy dissipations, including the viscous dissipation, the dissipations on the solid wall and at the contact line, as well as the dissipation due to the diffusion of surfactant, are identified from the analysis. A finite element method is developed for the continuum model. Numerical experiments are performed to demonstrate the influence of surfactant on the contact line dynamics. The different types of energy dissipations are compared numerically. © 2014 AIP Publishing LLC.
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    Differential response to exercise in claudin-low breast cancer
    (Oncotarget, 2017-01-01) Glass, OK; Bowie, M; Fuller, J; Darr, D; sary, JU; Boss, K; Choudhury, KR; Liu, X; Zhang, Z; Locasale, JW; Williams, C; Dewhirst, MW; Jones, LW; Seewaldt, V
    © Glass et al. Exposure to exercise following a breast cancer diagnosis is associated with reductions in the risk of recurrence. However, it is not known whether breast cancers within the same molecular-intrinsic subtype respond differently to exercise. Syngeneic mouse models of claudin-low breast cancer (i.e., EO771, 4TO7, and C3(1)SV40Tagp16- luc) were allocated to a uniform endurance exercise treatment dose (forced treadmill exercise) or sham-exercise (stationary treadmill). Compared to shamcontrols, endurance exercise treatment differentially affected tumor growth rate: 1- slowed (EO771), 2- accelerated (C3(1)SV40Tag-p16-luc), or 3- was not affected (4TO7). Differential sensitivity of the three tumor lines to exercise was paralleled by effects on intratumoral Ki-67, Hif1-a, and metabolic programming. Inhibition of Hif1-α synthesis by the cardiac glycoside, digoxin, completely abrogated exerciseaccelerated tumor growth in C3(1)SV40Tag-p16-luc. These results suggest that intratumoral Hif1-α expression is an important determinant of claudin-low breast cancer adaptation to exercise treatment.
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    Efficient Board-Level Functional-Fault Diagnosis with Missing Syndromes
    (2015-07-01) Jin, S; Ye, F; Zhang, Z; Chakrabarty, K; Gu, X
    Functional fault diagnosis is widely used in board manufacturing to ensure product quality and improve product yield. Advanced machine-learning techniques have recently been advocated for reasoning-based diagnosis; these techniques are based on the historical record of successfully repaired boards. However, traditional diagnosis systems fail to provide appropriate repair suggestions when the diagnostic logs are fragmented and some error outcomes, or syndromes, are not available during diagnosis. We describe the design of a diagnosis system that can handle missing syndromes and can be applied to four widely used machine-learning techniques. Several imputation methods are discussed and compared in terms of their effectiveness for addressing missing syndromes. Moreover, a syndrome-selection technique based on the minimumredundancy-maximum-relevance (mRMR) criteria is also incorporated to further improve the efficiency of the proposed methods. Two large-scale synthetic data sets generated from the log information of complex industrial boards in volume production are used to validate the proposed diagnosis system in terms of diagnosis accuracy and training time.
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    How Annealing and Charge Scavengers Affect Visible Emission from ZnO Nanocrystals
    (JOURNAL OF PHYSICAL CHEMISTRY C, 2016-03-10) Reish, ME; Zhang, Z; Ma, S; Harrison, I; Everitt, HO
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    Hydrogel-coated enzyme electrodes formed by GOx-mediated polymerization for glucose detecting
    (RSC Advances, 2015-01-01) Zhang, Z; Tang, Z; Su, T; Li, W; Wang, Q
    This communication reports the mild fabrication of a hydrogel-coated enzyme electrode for glucose detecting with high sensitivity (35.19 μA mM-1 cm-2) and robust stability.
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    The difference between alternative averages
    (Demographic Research, 2012-12-06) Vaupel, JW; Zhang, Z
    Background: Demographers have long been interested in how compositional change, e.g., change in age structure, affects population averages. Objective: We want to deepen understanding of how compositional change affects population averages. Results: The difference between two averages of a variable, calculated using alternative weighting functions, equals the covariance between the variable and the ratio of the weighting functions, divided by the average of the ratio. We compare weighted and unweighted averages and also provide examples of use of the relationship in analyses of fertility and mortality. Comments: Other uses of covariances in formal demography are worth exploring. © 2012 James W. Vaupel & Zhen Zhang.