Influence of catalyst deactivation on the nature of the steady state solutions for reactions on catalytic surfaces

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An Investigation on the Influence of Modeling Approach and Load Pattern on Seismic Performance of RC Structures

Non-linear Static Analysis serves as a suitable measure to evaluate the performance of a structural system. The careful selection of modelling approach and the load pattern is critical to arrive at an adequate performance evaluation. The present study seeks to evaluate and compare the response of an existing eight story reinforced concrete structure, through the application of different modeling approaches and load patterns prescribed by FEMA 356. The results indicates that, with extreme clarity, that in all cases, the shape of the lateral load distribution is what the response of the buildings is finely accustomed to. This is especially true when different patterns of load are considered. It can also be observed that there is a very small difference between various load patterns

Dynamic pricing models for electronic business

Dynamic pricing is the dynamic adjustment of prices to consumers depending upon the value these customers attribute to a product or service. Today’s digital economy is ready for dynamic pricing; however recent research has shown that the prices will have to be adjusted in fairly sophisticated ways, based on sound mathematical models, to derive the benefits of dynamic pricing. This article attempts to survey different models that have been used in dynamic pricing. We first motivate dynamic pricing and present underlying concepts, with several examples, and explain conditions under which dynamic pricing is likely to succeed. We then bring out the role of models in computing dynamic prices. The models surveyed include inventory-based models, data-driven models, auctions, and machine learning. We present a detailed example of an e-business market to show the use of reinforcement learning in dynamic pricing

Stable and Metastable vortex states and the first order transition across the peak effect region in weakly pinned 2H-NbSe_2

The peak effect in weakly pinned superconductors is accompanied by metastable vortex states. Each metastable vortex configuration is characterized by a different critical current density J_c, which mainly depends on the past thermomagnetic history of the superconductor. A recent model [G. Ravikumar, et al, Phys. Rev. B 61, R6479 (2000)] proposed to explain the history dependent J_c postulates a stable state of vortex lattice with a critical current density J_c^{st}, determined uniquely by the field and temperature. In this paper, we present evidence for the existence of the stable state of the vortex lattice in the peak effect region of 2H-NbSe_2. It is shown that this stable state can be reached from any metastable vortex state by cycling the applied field by a small amplitude. The minor magnetization loops obtained by repeated field cycling allow us to determine the pinning and "equilibrium" properties of the stable state of the vortex lattice at a given field and temperature unambiguously. The data imply the occurence of a first order phase transition from an ordered phase to a disordered vortex phase across the peak effect.Comment: 20 pages, 10 figures. Corresponding author: S. Ramakrishna

A randomized, double-blind, parallel, placebo-controlled study to evaluate efficacy and safety of a synergistic multi-herbal extract blend KaraHeart™ in supporting healthy cholesterol levels

Background: Hyperlipidemia is a condition involving abnormally high levels of lipids in the blood. Hyperlipidemia is a major risk factor for cardiovascular diseases and refers to either high levels of triglycerides (TGL) or cholesterol. Herbal supplements have been used in the management of cholesterol levels in Ayurveda, a complete medical system originating in India. KaraHeart™ is a multi-herbal extract synergistic blend that may help in the management of healthy cholesterol levels. The current study tested the efficacy, tolerability, and safety of KaraHeart™ versus a placebo in the management of cholesterol levels of patients with mild hyperlipidemia.Methods: This was a randomized, double-blind, parallel, and placebo-controlled study. A total of 100 patients were divided into two groups. One group was given KaraHeart™ and the other group was given a placebo for 120 days. Treatment results were assessed by checking the lipid profile parameters such as total cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL), very-low-density lipoprotein (VLDL), and TGL.Results: The study found that the herbal supplement KaraHeart™ significantly reduced levels of LDL, VLDL, TGL, and total cholesterol, while increasing the levels of HDL in the blood. Additionally, the study concluded that KaraHeart™ was safe to use.Conclusions: KaraHeart™ was shown to be safe and effective in the management of cholesterol levels

A study of supercooling of the disordered vortex phase via minor hysteresis loops in 2H-NbSe_2

We report on the observation of novel features in the minor hysteresis loops in a clean crystal of NbSe_2 which displays a peak effect. The observed behavior can be explained in terms of a supercooling of the disordered vortex phase while cooling the superconductor in a field. Also, the extent of spatial order in a flux line lattice formed in ascending fields is different from (and larger than) that in the descending fields below the peak position of the peak effect; this is attributed to unequal degree of annealing of the state induced by a change of field in the two cases.Comment: 5 pages of text + 6 figures, submitted to Phys. Rev.

Group descent algorithms for nonconvex penalized linear and logistic regression models with grouped predictors

Penalized regression is an attractive framework for variable selection problems. Often, variables possess a grouping structure, and the relevant selection problem is that of selecting groups, not individual variables. The group lasso has been proposed as a way of extending the ideas of the lasso to the problem of group selection. Nonconvex penalties such as SCAD and MCP have been proposed and shown to have several advantages over the lasso; these penalties may also be extended to the group selection problem, giving rise to group SCAD and group MCP methods. Here, we describe algorithms for fitting these models stably and efficiently. In addition, we present simulation results and real data examples comparing and contrasting the statistical properties of these methods

Effect of pinning and driving force on the metastability effects in weakly pinned superconductors and the determination of spinodal line pertaining to order-disorder transition

We explore the effect of varying drive on metastability features exhibited by the vortex matter in single crystals of 2H-NbSe$_2$ and CeRu$_2$ with varying degree of random pinning. An optimal balance between the pinning and driving force is needed to view the metastability effects in typically weakly pinned specimen of low temperature superconductors. As one uses samples with larger pinning in order to differentiate the response of different metastable vortex states, one encounters a new phenomena, viz., the second magnetization peak (SMP) anomaly prior to the PE. Interplay between the path dependence in the critical current density and the non-linearity in the electromagnetic response determine the metastability effects seen in first and the third harmonic response of the ac susceptibility across the temperature regions of the SMP and the PE. The limiting temperature above which metastability effects cease can be conveniently located in the third harmonic data, and the observed behavior can be rationalized within the Beans Critical State model. A vortex phase diagram showing the different vortex phases for a typically weakly pinned specimen has been constructed via the ac susceptibility data in a crystal of 2H-NbSe$_2$ which shows the SMP and the PE anomalies. The phase space of coexisting weaker and stronger pinned regions has been identified. It can be bifurcated into two parts, where the order and disorder dominate, respectively. The former part continuously connects to the reentrant disordered vortex phase pertaining to the small bundle pinning regime, where the vortices are far apart, interaction effects are weak and the polycrystalline form of flux line lattice prevails.Comment: Submitted to the Special Volume on Vortex State Studies, Pramana J. Phy

Genetic diversity analysis in tamarind (Tamarindus indica L.)

The present study conducted at Shimoga (Karnataka) during 2005–2008 is an attempt to examine genetic relatedness and genetic diversity among 13 Indian collections of Tamarind. Twenty eight selected arbitrary primers were used for characterization using RAPD that generated 131 fragments, of which 116 (88.54%) were polymorphic. Two genotypes, NTI62 and NTI84 were distinguished by unique band specific to them. The genetic similarity coefficient values suggested a wide genetic base for genotypes considered for the study. Cluster analysis based on unweighted pair group method using arithmetic average (UPGMA) clearly indicated that genotypes did not cluster according to their site of collection. This could be attributed to highly cross pollinating nature, small distribution area and that most tamarind genotypes grown in India are from seed source. &nbsp