1,327 research outputs found

    Antecedents and consequences of new product development and international new product rollout timeliness:an examination of mediating and moderating influences

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    The study examined the relationships between antecedents, timeliness in NPD and INPR, and consequences. A conceptual framework was tested using 232 new products from South Korean firms. The hypothesized relationships among the constructs in the model were evaluated by multiple regression and hierarchal regression analyses using SPSS 12 as well as by structural equation modelling (SEM) using SIMPLIS LISREL. In addition, confirmatory factor analysis (CFA) was carried out using SIMPLIS LISREL. In the direct relationships, cross-functional linkages and marketing synergy exhibited a statistically significant effect on NPD timeliness. The results also supported the influences of the HQ-subsidiary/agent relationship and NPD timeliness on INPR timeliness as well as INPR timeliness on performance. In the mediating effect tests, marketing proficiency significantly accounts for the relationships between cross-functional linkages and NPD timeliness, between marketing synergy and NPD timeliness, and between the HQ-subsidiary/agent relationship and INPR timeliness. Technical proficiency also mediates the effect of the HQ-subsidiary/agent relationship on INPR timeliness. The influence of NPD timeliness on new product performance in target markets is attributed to INPR timeliness. As for the results of the external environmentals and standardization influences, competitive intensity moderates the relationship between NPD timeliness and new product performance. Technology change also moderates the relationship between cross-functional linkages and NPD timeliness and between timeliness in NPD and INPR and performance. Standardization has a moderating role on the relationship between NPD timeliness and INPR timeliness. This study presents the answers to research questions which concern what factors are predictors of criterion variables, how antecedents influence timeliness in NPD and INPR and when the direct relationships in the INPR process are strengthened

    Application of Digital Anti-Coincidence Counting Method for Primary Activity Determination of 59Fe

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    As a radiopharmaceutical, the use of 59Fe is classified as a high pharmaceutical risk product. Therefore, a standard reference for activity measurement of 59Fe is necessary to ensure its metrological aspect. This paper describes an alternative method for primary activity determination of 59Fe for establishing a standard reference. The 59Fe solution was prepared using two different cocktails and measured by the 4pb(LS)-g counting system using a digital anti-coincidence counting method with emulated live-time of the extending dead-time. A final activity results at the reference time for the two samples series are (473.32± 2.55) kBq/g and (477.14 ± 2.42) kBq/g with quoted uncertainty evaluated at k = 1. The final activity was compared to the value obtained from the other two coincidence counting method and found to be in a good agreement within its uncertainty value

    Renormalization Effects in a Dilute Bose Gas

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    The low-density expansion for a homogeneous interacting Bose gas at zero temperature can be formulated as an expansion in powers of ρa3\sqrt{\rho a^3}, where ρ\rho is the number density and aa is the S-wave scattering length. Logarithms of ρa3\rho a^3 appear in the coefficients of the expansion. We show that these logarithms are determined by the renormalization properties of the effective field theory that describes the scattering of atoms at zero density. The leading logarithm is determined by the renormalization of the pointlike 333 \to 3 scattering amplitude.Comment: 10 pages, 1 postscript figure, LaTe

    Two-magnon Raman scattering in insulating cuprates: Modifications of the effective Raman operator

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    Calculations of Raman scattering intensities in spin 1/2 square-lattice Heisenberg model, using the Fleury-Loudon-Elliott theory, have so far been unable to describe the broad line shape and asymmetry of the two magnon peak found experimentally in the cuprate materials. Even more notably, the polarization selection rules are violated with respect to the Fleury-Loudon-Elliott theory. There is comparable scattering in B1gB_{1g} and A1gA_{1g} geometries, whereas the theory would predict scattering in only B1gB_{1g} geometry. We review various suggestions for this discrepency and suggest that at least part of the problem can be addressed by modifying the effective Raman Hamiltonian, allowing for two-magnon states with arbitrary total momentum. Such an approach based on the Sawatzsky-Lorenzana theory of optical absorption assumes an important role of phonons as momentum sinks. It leaves the low energy physics of the Heisenberg model unchanged but substantially alters the Raman line-shape and selection rules, bringing the results closer to experiments.Comment: 7 pages, 6 figures, revtex. Contains some minor revisions from previous versio

    Urine albumin/creatinine ratio below 30mg/g is a predictor of incident hypertension and cardiovascular mortality

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    BackgroundMicroalbuminuria is associated with cardiovascular disease (CVD) mortality, but whether lower levels of urine albumin excretion similarly predict CVD is uncertain. We investigated associations between urine albumin:creatinine ratio (UACR) <30 mg/g, and incident hypertension, incident diabetes mellitus, and all?cause and CVD mortality, during a maximum of 11 years of follow?up.Methods and ResultsIndividuals (37 091) in a health screening program between 2002 and 2012 with baseline measurements of UACR were studied. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% CIs for incident hypertension, incident diabetes mellitus, and mortality outcomes (lowest UACR quartile as reference) at follow?up. For linear risk trends, the quartile rank was used as a continuous variable in regression models. Nine?hundred sixty?three cases of incident hypertension, 511 cases of incident diabetes mellitus, and 349 deaths occurred during follow?up. In the fully adjusted models, there was a significant HR for the association between UACR and incident hypertension (highest UACR quartile HR 1.95 [95% CI 1.51, 2.53], P?value for trend across UACR quartiles P<0.001). In contrast, the association between UACR and incident diabetes mellitus was not significant (highest UACR quartile, HR 1.15 [95% CI 0.79, 1.66], P?value for trend P=0.20). For CVD mortality, with increasing UACR quartiles, there was a significant increase in HR across quartiles, P=0.029, (for all?cause mortality, P=0.078).ConclusionsLow levels of albuminuria, UACR below 30 mg/g, are associated with increased risk of incident hypertension and CVD mortality at follow?up, but are not associated with increased risk of incident diabetes mellitus

    Elimination of leakage in GaN-on-diamond

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    The use of chemical vapor deposition diamond as a substrate for gallium nitride (GaN) to form GaN- on-diamond has the potential to allow for higher linear power densities in GaN high electron mobility transistors (HEMTs). The increase in GaN HEMT power density on diamond has been limited to date by the electrical leakage in GaN-on-diamond substrates. In this paper we show that to eliminate buffer leakage in silicon based GaN-on- diamond, you have to completely remove the transition layers used to grow high quality GaN on the original host silicon. By completely removing the transition layers in GaN-on-diamond, we demonstrated buffer leakage comparable to the leakage in GaN on silicon carbide

    Sulfuric acid and hydrogen peroxide surface passivation effects on AlGaN/GaN high electron mobility transistors

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    In this work, we have compared SiNx passivation, hydrogen peroxide, and sulfuric acid treatment on AlGaN/GaN HEMTs surface after full device fabrication on Si substrate. Both the chemical treatments resulted in the suppression of device pinch-off gate leakage current below 1 μA/mm, which is much lower than that for SiNx passivation. The greatest suppression over the range of devices is observed with the sulfuric acid treatment. The device on/off current ratio is improved (from 104–105 to 107) and a reduction in the device sub-threshold (S.S.) slope (from ∼215 to 90 mV/decade) is achieved. The sulfuric acid is believed to work by oxidizing the surface which has a strong passivating effect on the gate leakage current. The interface trap charge density (Dit ) is reduced (from 4.86 to 0.90 × 1012 cm−2 eV−1), calculated from the change in the device S.S. The gate surface leakage current mechanism is explained by combined Mott hopping conduction and Poole Frenkel models for both untreated and sulfuric acid treated devices. Combining the sulfuric acid treatment underneath the gate with the SiNx passivation after full device fabrication results in the reduction of Dit and improves the surface related current collapse

    A Bayesian Maximum Entropy approach to address the change of support problem in the spatial analysis of childhood asthma prevalence across North Carolina

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    The spatial analysis of data observed at different spatial observation scales leads to the change of support problem (COSP). A solution to the COSP widely used in linear spatial statistics consists in explicitly modeling the spatial autocorrelation of the variable observed at different spatial scales. We present a novel approach that takes advantage of the nonlinear Bayesian Maximum Entropy (BME) extension of linear spatial statistics to address the COSP directly without relying on the classical linear approach. Our procedure consists in modeling data observed over large areas as soft data for the process at the local scale. We demonstrate the application of our approach to obtain spatially detailed maps of childhood asthma prevalence across North Carolina (NC). Because of the high prevalence of childhood asthma in NC, the small number problem is not an issue, so we can focus our attention solely to the COSP of integrating prevalence data observed at the county level together with data observed at a targeted local scale equivalent to the scale of school districts. Our spatially detailed maps can be used for different applications ranging from exploratory and hypothesis-generating analyses to targeting intervention and exposure mitigation efforts

    Statistics of pre-localized states in disordered conductors

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    The distribution function of local amplitudes of single-particle states in disordered conductors is calculated on the basis of the supersymmetric σ\sigma-model approach using a saddle-point solution of its reduced version. Although the distribution of relatively small amplitudes can be approximated by the universal Porter-Thomas formulae known from the random matrix theory, the statistics of large amplitudes is strongly modified by localization effects. In particular, we find a multifractal behavior of eigenstates in 2D conductors which follows from the non-integer power-law scaling for the inverse participation numbers (IPN) with the size of the system. This result is valid for all fundamental symmetry classes (unitary, orthogonal and symplectic). The multifractality is due to the existence of pre-localized states which are characterized by power-law envelopes of wave functions, ψt(r)2r2μ|\psi_t(r)|^2\propto r^{-2\mu}, μ<1\mu <1. The pre-localized states in short quasi-1D wires have the power-law tails ψ(x)2x2|\psi (x)|^2\propto x^{-2}, too, although their IPN's indicate no fractal behavior. The distribution function of the largest-amplitude fluctuations of wave functions in 2D and 3D conductors has logarithmically-normal asymptotics.Comment: RevTex, 17 twocolumn pages; revised version (several misprint corrected
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