Metallic clusters on a model surface: quantum versus geometric effects

We determine the structure and melting behavior of supported metallic clusters using an ab initio density-functional-based treatment of intracluster interactions and an approximate treatment of the surface as an idealized smooth plane yielding an effective Lennard-Jones interaction with the ions of the cluster. We apply this model to determine the structure of sodium clusters containing from 4 to 22 atoms, treating the cluster-surface interaction strength as a variable parameter. For a strong cluster-surface interaction, the clusters form two-dimensional (2D) monolayer structures; comparisons with calculations of structure and dissociation energy performed with a classical Gupta interatomic potential show clearly the role of quantum shell effects in the metallic binding in this case, and evidence is presented that these shell effects correspond to those for a confined 2D electron gas. The thermodynamics and melting behavior of a supported Na_20 cluster is considered in detail using the model for several cluster-surface interaction strengths. We find quantitative differences in the melting temperatures and caloric curve from density-functional and Gupta treatments of the valence electrons. A clear dimensional effect on the melting behavior is also demonstrated, with 2D structures showing melting temperatures above those of the bulk or (at very strong cluster-surface interactions) no clear meltinglike transition

Supporting Collaborative Health Tracking in the Hospital: Patients' Perspectives

The hospital setting creates a high-stakes environment where patients' lives depend on accurate tracking of health data. Despite recent work emphasizing the importance of patients' engagement in their own health care, less is known about how patients track their health and care in the hospital. Through interviews and design probes, we investigated hospitalized patients' tracking activity and analyzed our results using the stage-based personal informatics model. We used this model to understand how to support the tracking needs of hospitalized patients at each stage. In this paper, we discuss hospitalized patients' needs for collaboratively tracking their health with their care team. We suggest future extensions of the stage-based model to accommodate collaborative tracking situations, such as hospitals, where data is collected, analyzed, and acted on by multiple people. Our findings uncover new directions for HCI research and highlight ways to support patients in tracking their care and improving patient safety

A Systematic Study of Electronic Structure from Graphene to Graphane

While graphene is a semi-metal, a recently synthesized hydrogenated graphene called graphane, is an insulator. We have probed the transformation of graphene upon hydrogenation to graphane within the framework of density functional theory. By analyzing the electronic structure for eighteen different hydrogen concentrations, we bring out some novel features of this transition. Our results show that the hydrogenation favors clustered configurations leading to the formation of compact islands. The analysis of the charge density and electron localization function (ELF) indicates that as hydrogen coverage increases the semi-metal turns into a metal showing a delocalized charge density, then transforms into an insulator. The metallic phase is spatially inhomogeneous in the sense, it contains the islands of insulating regions formed by hydrogenated carbon atoms and the metallic channels formed by contiguous bare carbon atoms. It turns out that it is possible to pattern the graphene sheet to tune the electronic structure. For example removal of hydrogen atoms along the diagonal of the unit cell yielding an armchair pattern at the edge gives rise to a band gap of 1.4 eV. We also show that a weak ferromagnetic state exists even for a large hydrogen coverage whenever there is a sub-lattice imbalance in presence of odd number of hydrogen atoms.Comment: This is an author-created, un-copyedited version of an article accepted for publication in J. Phys.: Condens. Matte

The Absolute of Advaita and the Spirit of Hegel: Situating Vedānta on the Horizons of British Idealisms

$\textit{Purpose}$ A significant volume of philosophical literature produced by Indian academic philosophers in the first half of the twentieth century can be placed under the rubric of ‘Śaṁkara and X’, where X is Hegel, or a German or a British philosopher who had commented on, elaborated or critiqued the Hegelian system. We will explore in this essay the philosophical significance of Hegel-influenced systems as an intellectual conduit for these Indo-European conceptual encounters, and highlight how for some Indian philosophers the British variations on Hegelian systems were both a point of entry into debates over ‘idealism’ and ‘realism’ in contemporary European philosophy and an occasion for defending Advaita against the charge of propounding a doctrine of world illusionism. $\textit{Methodology}$ Our study of the philosophical enquiries of A.C. Mukerji, P.T. Raju, and S.N.L. Shrivastava indicates that they developed distinctive styles of engaging with Hegelian idealisms as they reconfigured certain aspects of the classical Advaita of Śaṁkara through contemporary vocabulary. $\textit{Result and Conclusion}$ These appropriations of Hegelian idioms can be placed under three overlapping styles: (a) Mukerji was partly involved in locating Advaita in an intermediate conceptual space between, on the one hand, Kantian agnosticism and, on the other hand, Hegelian absolutism; (b) Raju and Shrivastava presented Advaitic thought as the fulfilment of certain insights of Hegel and F.H. Bradley; and (c) the interrogations of Hegel’s ‘idealism’ provided several Indian academic philosophers with a hermeneutic opportunity to revisit the vexed question of whether the ‘idealism’ of Śaṁkara reduces the phenomenal world, structured by $\textit{māyā}$, to a bundle of ideas

Evaluation of a real-time PCR assay for simultaneous detection of Kingella kingae and Staphylococcus aureus from synovial fluid in suspected septic arthritis

Direct plating of synovial fluid (SF) on agar-based media often fails to identify pathogens in septic arthritis (SA). We developed a PCR assay for the simultaneous detection of Kingella kingae and Staphylococcus aureus from SF to evaluate molecular detection in SF and to estimate the incidence of K. kingae in SA in North America. The assay was based on detection of the cpn60 gene of K. kingae and the spa gene of S. aureus in multiplex real-time PCR. K. kingae was identified in 50% of patients between 0 and 5 yr of age (n=6) but not in any patients >18 yr old (n=105). Direct plating of SF on agar-based media failed to detect K. kingae in all samples. The PCR assay was inferior to the culture-based method for S. aureus, detecting only 50% of culture-positive cases. Our findings suggest that K. kingae is a common pathogen in pediatric SA in North America, in agreement with previous reports from Europe. PCR-based assays for the detection of K. kingae may be considered in children with SA, especially in those with a high degree of clinical suspicion