New Benchmark Set of Transition-Metal Coordination Reactions for the Assessment of Density Functionals

We present the WCCR10 data set of ten ligand dissociation energies of large cationic transition metal complexes for the assessment of approximate exchange--correlation functionals. We analyze nine popular functionals, namely BP86, BP86-D3, B3LYP, B3LYP-D3, B97-D-D2, PBE, TPSS, PBE0, and TPSSh by mutual comparison and by comparison to experimental gas-phase data measured with well-known precision. The comparison of all calculated data reveals a large, system-dependent scattering of results with nonnegligible consequences for computational chemistry studies on transition metal compounds. Considering further the comparison with experiment, the non-empirical functionals PBE and TPSS turn out to be among the best functionals for our reference data set. The deviation can be lowered further by including Hartree--Fock exchange. Accordingly, PBE0 and TPSSh are the two most accurate functionals for our test set, but also these functionals exhibit deviations from experiment by up to 50 kJ/mol for individual reactions. As an important result we found no functional to be reliable for all reactions. Furthermore, for some of the ligand dissociation energies studied in this work, dispersion corrections yield results which increase the deviation from experiment. This deviation increases further if structure optimization including dispersion corrections is performed. Finally, we compare our results to other benchmark studies and highlight that the performance assessed for different density functionals depends significantly on the reference molecule set chosen.Comment: 36 pages, 7 figures, 3 table

04441 Abstracts Collection -- Mobile Information Management

From 24.10.04 to 29.10.04, the Dagstuhl Seminar 04441 ``Mobile Information Management\u27\u27 was held in the International Conference and Research Center (IBFI), Schloss Dagstuhl. During the seminar, several participants presented their current research, and ongoing work and open problems were discussed. Abstracts of the presentations given during the seminar as well as abstracts of seminar results and ideas are put together in this paper. The first section describes the seminar topics and goals in general. Links to extended abstracts or full papers are provided, if available

Using Permuted States of Validated Simulation to Analyze Conflict Rates in Optimistic Replication

Optimistic replication provides high data availability in the presence of network outages. Although widely deployed, this relaxed consistency model introduces concurrent updates, whose behavior is poorly understood due to the vast state space. This paper introduces the notion of permuted states to eliminate system states that are redundant and unreachable, which can constitute the majority of states (4069 out of 4096 for four replicas). With the aid of permuted states, we are for the first time able to construct analytical models beyond the two-replica case. By examining the analysis for 2 to 4 replicas, we can demystify the process of forming identical conflicts—the most common conflict type at high replication factors. Additionally, we have automated and optimized the generation of permuted states, which allows us to explore higher replication factors (up to 10 replicas) using hybrid techniques. It also allows us to validate our results with existing simulations based on actual replication mechanisms, which previously were analytically validated with only one pair of replicas. Finally, we have discovered that update locality and bimodal access patterns are the primary factors contributing to the formation of identical conflicts

Length of carotid stenosis predicts peri-procedural stroke or death and restenosis in patients randomized to endovascular treatment or endarterectomy.

BACKGROUND: The anatomy of carotid stenosis may influence the outcome of endovascular treatment or carotid endarterectomy. Whether anatomy favors one treatment over the other in terms of safety or efficacy has not been investigated in randomized trials. METHODS: In 414 patients with mostly symptomatic carotid stenosis randomized to endovascular treatment (angioplasty or stenting; n = 213) or carotid endarterectomy (n = 211) in the Carotid and Vertebral Artery Transluminal Angioplasty Study (CAVATAS), the degree and length of stenosis and plaque surface irregularity were assessed on baseline intraarterial angiography. Outcome measures were stroke or death occurring between randomization and 30 days after treatment, and ipsilateral stroke and restenosis ≥50% during follow-up. RESULTS: Carotid stenosis longer than 0.65 times the common carotid artery diameter was associated with increased risk of peri-procedural stroke or death after both endovascular treatment [odds ratio 2.79 (1.17-6.65), P = 0.02] and carotid endarterectomy [2.43 (1.03-5.73), P = 0.04], and with increased long-term risk of restenosis in endovascular treatment [hazard ratio 1.68 (1.12-2.53), P = 0.01]. The excess in restenosis after endovascular treatment compared with carotid endarterectomy was significantly greater in patients with long stenosis than with short stenosis at baseline (interaction P = 0.003). Results remained significant after multivariate adjustment. No associations were found for degree of stenosis and plaque surface. CONCLUSIONS: Increasing stenosis length is an independent risk factor for peri-procedural stroke or death in endovascular treatment and carotid endarterectomy, without favoring one treatment over the other. However, the excess restenosis rate after endovascular treatment compared with carotid endarterectomy increases with longer stenosis at baseline. Stenosis length merits further investigation in carotid revascularisation trials

Quantum bits with Josephson junctions

Already in the first edition of this book (Barone and Paterno, "Fundamentals and Physics and Applications of the Josephson Effect", Wiley 1982), a great number of interesting and important applications for Josephson junctions were discussed. In the decades that have passed since then, several new applications have emerged. This chapter treats one such new class of applications: quantum optics and quantum information processing (QIP) based on superconducting circuits with Josephson junctions. In this chapter, we aim to explain the basics of superconducting quantum circuits with Josephson junctions and demonstrate how these systems open up new prospects, both for QIP and for the study of quantum optics and atomic physics.Comment: 30 pages, 10 figures. Book chapter for a new edition of Barone and Paterno's "Fundamentals and Physics and Applications of the Josephson Effect". Final versio

Molecular insights into the behaviour of bile salts at interfaces: a key to their role in lipid digestion

Hypotheses. Understanding the mechanisms underlying lipolysis is crucial to address the ongoing obesity crisis and associated cardiometabolic disorders. Bile salts (BS), biosurfactants present in the small intestine, play key roles in lipid digestion and absorption. It is hypothesised that their contrasting functionalities – adsorption at oil/water interfaces and shuttling of lipolysis products away from these interfaces – are linked to their structural diversity. We investigate the interfacial films formed by two BS, sodium taurocholate (NaTC) and sodium taurodeoxycholate (NaTDC), differing by the presence or absence of a hydroxyl group on their steroid skeleton. Experiments. Their adsorption behaviour at the air/water interface and interaction with a phospholipid monolayer – used to mimic a fat droplet interface – were assessed by surface pressure measurements and ellipsometry, while interfacial morphologies were characterised in the lateral and perpendicular directions by Brewster angle microscopy, X-ray and neutron reflectometry, and molecular dynamics simulations. Findings. Our results provide a comprehensive molecular-level understanding of the mechanisms governing BS interfacial behaviour. NaTC shows a higher affinity for the air/water and lipid/water interfaces, and may therefore favour enzyme adsorption, whereas NaTDC exhibits a higher propensity for desorption from these interfaces, and may thus more effectively displace hydrolysis products from the interface, through dynamic exchange

Securing Distributed Adaptation

Open architecture networks provide applications with fine-grained control over network elements. With this control comes the risk of misuse and new challenges to security beyond those present in conventional networks. One particular security requirement is the ability of applications to protect the secrecy and integrity of transmitted data while still allowing trusted active elements within the network to operate on that data. This paper describes mechanisms for identifying trusted nodes within a network and securely deploying adaptation instructions to those nodes while preventing unauthorized access and modification of application data. Promising experimental results of our implementation within the Conductor adaptation framework will also be presented, suggesting that such features can be incorporated into real networks