Methylene-Only Subspectra in \u3csup\u3e13\u3c/sup\u3eC CPMAS Using a New Double Quantum Filtering Sequence

Methodology for the assignment of 13C CPMAS spectra is still in its infancy. Previous methods of CPMAS spectral editing have utilized differences in the strength of the 13C–1H dipolar interaction or the rate and spin thermodynamics of crosspolarization from protons to carbon, to differentiate between quaternary, tertiary, and methylene carbons. We introduce a different approach, which is based on the fact that double-quantum coherence develops between the protons of a methylene group considerably faster than between most other proton spin pairs in an organic solid. We generate this coherence, filter it, convert it back to single quantum, and then crosspolarize selectively to carbon, followed by a short period of reversed crosspolarization to null out unwanted coherence generated from longer distance spin pairs. The sequence has been named DQCP. While the signal-to-noise of this method is poorer than ordinary CP, it is comparable to previous methods for generating methylene-only spectra, and the technique is straightforward and easy to implement

Competitive Consequences of Using a Category Captain

Many retailers designate one national brand manufacturer in each product category as a “category captain” to help manage the entire category. A category captain may perform demand-enhancing services such as better shelf arrangements, shelf-space management, and design and management of in-store displays. In this paper, we examine when and why a retailer may engage one manufacturer exclusively as a category captain to provide such service and the implications. We find that demand substitutability of competing brands gives rise to a service efficiency effect—service that expands the category is more effective in increasing a manufacturer\u27s sales and margin than service that shifts demand from a rival\u27s brand. We show that the service efficiency effect may motivate a category captain to provide a service that benefits all brands in the category even though doing so is more costly. We further show that, in categories that are less price competitive, there is higher competition between manufacturers to become the category captain. Consequently, a retailer may obtain better service by using a category captain than by engaging both manufacturers simultaneously. Our findings may help explain why a retailer may rely on a category captain despite concerns regarding opportunism and why there is limited empirical evidence of harm to rival manufacturers

Competitive Consequences of Using a Category Captain

Many retailers designate one national brand manufacturer in each product category as a “category captain” to help manage the entire category. A category captain may perform demand-enhancing services such as better shelf arrangements, shelf-space management, and design and management of in-store displays. In this paper, we examine when and why a retailer may engage one manufacturer exclusively as a category captain to provide such service and the implications. We find that demand substitutability of competing brands gives rise to a service efficiency effect—service that expands the category is more effective in increasing a manufacturer\u27s sales and margin than service that shifts demand from a rival\u27s brand. We show that the service efficiency effect may motivate a category captain to provide a service that benefits all brands in the category even though doing so is more costly. We further show that, in categories that are less price competitive, there is higher competition between manufacturers to become the category captain. Consequently, a retailer may obtain better service by using a category captain than by engaging both manufacturers simultaneously. Our findings may help explain why a retailer may rely on a category captain despite concerns regarding opportunism and why there is limited empirical evidence of harm to rival manufacturers

An Evaluation on Wind Energy Potential using Multi-Objective Optimization-based Non-dominated Sorting Genetic Algorithm III

Wind energy is an abundant renewable energy resource that is extensively used worldwide in recent years. The present work proposes a new Multi-Objective Optimization (MOO) based genetic algorithm (GA) model for a wind energy system. The proposed algorithm consists of non-dominated sorting which focuses to maximize the power extraction of the wind turbine and the lifetime of the battery. Also, the performance characteristics of the wind turbine and battery energy storage system (BESS) are analyzed specifically torque, current, voltage, state of charge (SOC), and internal resistance. The complete analysis is carried out in the MATLAB/Simulink platform. The simulated results are compared with existing optimization techniques such as single-objective, multi-objective, and non-dominating sorting GA II (Genetic Algorithm-II). From the observed results, the NSGA III optimization algorithm offers superior performance notably higher turbine power output with higher torque rate, lower speed variation, and lesser degradation rate of the battery. This result attested to the fact that the proposed optimization tool can extract a higher rate of power from a self-excited induction generator (SEIG) when compared with a conventional optimization tool.publishedVersio

Static Correlation and Dynamical Properties of Tb3+-moments in Tb2Ti2O7 -Neutron Scattering Study-

Static and dynamical properties of the magnetic moment system of pyrochlore compound Tb2Ti2O7 with strong magnetic frustration, have been investigated down to the temperature T=0.4 K by neutron scattering on a single crystal sample. The scattering vector (Q)-dependence of the magnetic scattering intensity becomes appreciable with decreasing T at around 30 K, indicating the development of the magnetic correlation. From the observed energy profiles, the elastic, quasi elastic and inelastic components have been separately obtained. The quasi elastic component corresponds to the diffusive motion of the magnetic moments within the lowest states, which are formed of the lowest energy levels of Tb3+ ions. Magnetic correlation pattern which can roughly reproduce the Q-dependence of the scattering intensities of the elastic and quasi elastic component is discussed based on the trial calculations for clusters of 7 moments belonging to two corner-sharing tetrahedra. A possible origin of the glassy state, which develops at around 1.5 K with decreasing T is discussed.Comment: 10 pages, 12 figures, to be published in J. Phys. Soc. Jpn. 71(2002)No.2 59

Local lattice disorder in the geometrically-frustrated spin glass pyrochlore Y2Mo2O7

The geometrically-frustrated spin glass Y2Mo2O7 has been considered widely to be crystallographically ordered with a unique nearest neighbor magnetic exchange interaction, J. To test this assertion, we present x-ray-absorption fine-structure results for the Mo and Y K edges as a function of temperature and compare them to results from a well-ordered pyrochlore, Tl2Mn2O7. We find that the Mo-Mo pair distances are significantly disordered at approximately right angles to the Y-Mo pairs. These results strongly suggest that lattice disorder nucleates the spin-glass phase in this material.Comment: 9 pages, 2 Postscript figures, Phys. Rev. B: Rapid, in pres

Application of a Household-Based Molecular Xenomonitoring Strategy to Evaluate the Lymphatic Filariasis Elimination Program in Tamil Nadu, India

Lymphatic filariasis (LF) is one of the world’s foremost debilitating infectious diseases with nearly 800 million people at risk of infection. Given that LF is a mosquito-borne disease, the use of molecular xenomonitoring (MX) to detect parasite DNA/RNA in mosquitoes can serve as a valuable tool for LF monitoring and evaluation, particularly in Culexvector areas. We investigated using MX in a low-level prevalence district of Tamil Nadu, India by applying a household-based sampling strategy to determine trap location sites. Two independent mosquito samples were collected in each of a higher human infection hotspot area (sites with community microfilaria prevalence �1%) and across a larger evaluation area that also encompassed the hotspots. Pooled results showed mostly reproducible outcomes in both settings and a significant higher pool positivity in the hotspot area. A follow-up survey conducted two years later reconfirmed these findings while also showing a reduction in pool positivity and estimated prevalence of infection in mosquitoes in both settings. The utilization of a household-based sampling strategy for MX proved effective and should be further validated in wider epidemiological settings

Intermediate Valence Model for the Colossal Magnetoresistance in Tl_{2}Mn_{2}O_{7}

The colossal magnetoresistance exhibited by Tl_{2}Mn_{2}O_{7} is an interesting phenomenon, as it is very similar to that found in perovskite manganese oxides although the compound differs both in its crystalline structure and electronic properties from the manganites. At the same time, other pyrochlore compounds, though sharing the same structure with Tl_{2}Mn_{2}O_{7}, do not exhibit the strong coupling between magnetism and transport properties found in this material. Mostly due to the absence of evidence for significant doping into the Mn-O sublattice, and the tendency of Tl to form conduction bands, the traditional double exchange mechanism mentioned in connection with manganites does not seem suitable to explain the experimental results in this case. We propose a model for Tl_{2}Mn_{2}O_{7} consisting of a lattice of intermediate valence ions fluctuating between two magnetic configurations, representing Mn-3d orbitals, hybridized with a conduction band, which we associate with Tl. This model had been proposed originally for the analysis of intermediate valence Tm compounds. With a simplified treatment of the model we obtain the electronic structure and transport properties of Tl_{2}Mn_{2}O_{7}, with good qualitative agreement to experiments. The presence of a hybridization gap in the density of states seems important to understand the reported Hall data.Comment: 8 pages + 5 postscript fig

Epidemiology and risk factors of chronic kidney disease in India – results from the SEEK (Screening and Early Evaluation of Kidney Disease) study

Background: There is a rising incidence of chronic kidney disease that is likely to pose major problems for both healthcare and the economy in future years. In India, it has been recently estimated that the age-adjusted incidence rate of ESRD to be 229 per million population (pmp), and >100,000 new patients enter renal replacement programs annually. Methods: We cross-sectionally screened 6120 Indian subjects from 13 academic and private medical centers all over India. We obtained personal and medical history data through a specifically designed questionnaire. Blood and urine samples were collected. Results: The total cohort included in this analysis is 5588 subjects. The mean ± SD age of all participants was 45.22 ± 15.2 years (range 18–98 years) and 55.1% of them were males and 44.9% were females. The overall prevalence of CKD in the SEEK-India cohort was 17.2% with a mean eGFR of 84.27 ± 76.46 versus 116.94 ± 44.65 mL/min/1.73 m2 in non-CKD group while 79.5% in the CKD group had proteinuria. Prevalence of CKD stages 1, 2, 3, 4 and 5 was 7%, 4.3%, 4.3%, 0.8% and 0.8%, respectively. Conclusion: The prevalence of CKD was observed to be 17.2% with ~6% have CKD stage 3 or worse. CKD risk factors were similar to those reported in earlier studies. It should be stressed to all primary care physicians taking care of hypertensive and diabetic patients to screen for early kidney damage. Early intervention may retard the progression of kidney disease. Planning for the preventive health policies and allocation of more resources for the treatment of CKD/ESRD patients are imperative in India