A Generalization of Poisson-Nijenhuis Structures

We generalize Poisson-Nijenhuis structures. We prove that on a manifold endowed with a Nijenhuis tensor and a Jacobi structure which are compatible, there is a hierarchy of pairwise compatible Jacobi structures. Furthermore, we study the homogeneous Poisson-Nijenhuis structures and their relations with Jacobi structures.Comment: 21 pages, Late

Reduction of Jacobi manifolds via Dirac structures theory

We first recall some basic definitions and facts about Jacobi manifolds, generalized Lie bialgebroids, generalized Courant algebroids and Dirac structures. We establish an one-one correspondence between reducible Dirac structures of the generalized Lie bialgebroid of a Jacobi manifold $(M,\Lambda,E)$ for which 1 is an admissible function and Jacobi quotient manifolds of $M$. We study Jacobi reductions from the point of view of Dirac structures theory and we present some examples and applications.Comment: 18 page

Jacobi quasi-Nijenhuis Algebroids

In this paper, for a Jacobi algebroid $A$, by introducing the notion of Jacobi quasi-Nijenhuis algebroids, which is a generalization of Poisson quasi-Nijenhuis manifolds introduced by Sti\'{e}non and Xu, we study generalized complex structures on the Courant-Jacobi algebroid $A\oplus A^*$, which unifies generalized complex (contact) structures on an even(odd)-dimensional manifold.Comment: 17 pages, no figur

AV-Courant algebroids and generalized CR structures

We construct a generalization of Courant algebroids which are classified by the third cohomology group $H^3(A,V)$, where $A$ is a Lie Algebroid, and $V$ is an $A$-module. We see that both Courant algebroids and $\mathcal{E}^1(M)$ structures are examples of them. Finally we introduce generalized CR structures on a manifold, which are a generalization of generalized complex structures, and show that every CR structure and contact structure is an example of a generalized CR structure.Comment: 18 page

Board review course effect on resident in-training examination

Background The in-training examination is a national and yearly exam administered by the American Board of Emergency Medicine to all emergency medicine residents in the USA. The purpose of the examination is to evaluate a resident’s progress toward obtaining the fundamental knowledge to practice independent emergency medicine. Aims The purpose of this study was to determine the effects of a 40 hour board review lecture course on the resident in-training examination in emergency medicine. Methods A 40 hour board review lecture course was designed and implemented during the weekly 5 hour long resident conferences during the 8 weeks preceding the in-training examination date in 2006. Attendance was manda-tory at the Accreditation Council for Graduate Medical Education (ACGME) standard of 70 % or greater. A positive result was considered to be a 10 % increase or greater in the resident’s individual national class percentile ranking among their national peers for their class year for the emergency medicine in-training examination. A resident was excluded from the study if there was no 2005 in-training examination score for self-comparison. The 95% confidence intervals (CI) were used to analyze the results. Results Of 16 residents, 1 (6.25%; 95 % CI: 0–18%) showed a positive result of increasing their national class percentile ranking by 10 % or greater. For the PGY2, one of the eight had a positive result (12.5%; 95 % CI: 0–35.4%). For PGY3, no resident (0%; 95 % CI: 0–35.4%) had a positive result. Conclusions A 40 hour board review lecture course has no positive effect on improving a resident’s in-training examination score

Gravitational waves: search results, data analysis and parameter estimation

The Amaldi 10 Parallel Session C2 on gravitational wave (GW) search results, data analysis and parameter estimation included three lively sessions of lectures by 13 presenters, and 34 posters. The talks and posters covered a huge range of material, including results and analysis techniques for ground-based GW detectors, targeting anticipated signals from different astrophysical sources: compact binary inspiral, merger and ringdown; GW bursts from intermediate mass binary black hole mergers, cosmic string cusps, core-collapse supernovae, and other unmodeled sources; continuous waves from spinning neutron stars; and a stochastic GW background. There was considerable emphasis on Bayesian techniques for estimating the parameters of coalescing compact binary systems from the gravitational waveforms extracted from the data from the advanced detector network. This included methods to distinguish deviations of the signals from what is expected in the context of General Relativity

A reliability-aware chance-constrained battery sizing method for island microgrid

Island Microgrids can coordinate local energy resources, provide post-fault reliability improvements for local customers, and aggregate local power and energy resources to offer services to the wider system. A crucial component of an Island Microgrid is the battery energy storage system, which can manage local imbalances, alleviate constraints, and improve reliability by enabling post-fault islanding. A planning and sizing method is required to quantify and maximize the benefits of battery energy storage while avoiding over-investment and under-utilization. This paper combines comprehensive reliability assessment with chance-constrained convex optimization, via second-order cone programming, to optimally size energy storage within an Island Microgrid. Chance constraints are applied to the battery state-of-charge to avoid sizing the energy storage to accommodate extreme cases of uncertainty, avoiding uneconomic investment. The probability of reaching a state-of-charge constraint also indicates the likelihood that the battery energy storage system will be unable to facilitate island operation in the event of an outage, which affects the Island Microgrid reliability. The method is demonstrated on a real Austrian distribution network as part of the MERLON project. Results illustrate that an optimal trade-off can be identified between system reliability and operating cost when the probability of violating the chance constraints is 4.8%

Direct Introduction of a Dimesitylboryl Group Using Base-Mediated Substitution of Aryl Halides with Silyldimesitylborane

The first dimesitylboryl substitution of aryl halides with a silylborane bearing a dimesitylboryl group in the presence of alkali-metal alkoxides is described. The reactions of aryl bromides or iodides with Ph2MeSi-BMes(2) and Na(OtBu) afforded the desired aryl dimesitylboranes in good to high yields and with high borylation/silylation ratios. Selective reaction of the sterically less-hindered C-Br bond of dibromoarenes provided monoborylated products. This reaction was used to rapidly construct a D-pi-A aryl dimesityl borane with a non-symmetrical biphenyl spacer

Deformation correlations, stress field switches and evolution of an orogenic intersection: the Pan-African Kaoko-Damara orogenic junction, Namibia

Age calibrated deformation histories established by detailed mapping and dating of key magmatic time markers are correlated across all tectono-metamorphic provinces in the Damara Orogenic System. Correlations across structural belts result in an internally consistent deformation framework with evidence of stress field rotations with similar timing, and switches between different deformation events. Horizontal principle compressive stress rotated clockwise ∼180° in total during Kaoko Belt evolution, and ∼135° during Damara Belt evolution. At most stages, stress field variation is progressive and can be attributed to events within the Damara Orogenic System, caused by changes in relative trajectories of the interacting Rio De La Plata, Congo, and Kalahari Cratons. Kaokoan orogenesis occurred earliest and evolved from collision and obduction at ∼590 Ma, involving E–W directed shortening, progressing through different transpressional states with ∼45° rotation of the stress field to strike-slip shear under NW–SE shortening at ∼550–530 Ma. Damaran orogenesis evolved from collision at ∼555–550 Ma with NW–SE directed shortening in common with the Kaoko Belt, and subsequently evolved through ∼90° rotation of the stress field to NE–SW shortening at ∼512–508 Ma. Both Kaoko and Damara orogenic fronts were operating at the same time, with all three cratons being coaxially convergent during the 550–530 Ma period; Rio De La Plata directed SE against the Congo Craton margin, and both together over-riding the Kalahari Craton margin also towards the SE. Progressive stress field rotation was punctuated by rapid and significant switches at ∼530–525 Ma, ∼508 Ma and ∼505 Ma. These three events included: (1) Culmination of main phase orogenesis in the Damara Belt, coinciding with maximum burial and peak metamorphism at 530–525 Ma. This occurred at the same time as termination of transpression and initiation of transtensional reactivation of shear zones in the Kaoko Belt. Principle compressive stress switched from NW–SE to NNW–SSE shortening in both Kaoko and Damara Belts at this time. This marks the start of Congo-Kalahari stress field overwhelming the waning Rio De La Plata-Congo stress field, and from this time forward contraction across the Damara Belt generated the stress field governing subsequent low-strain events in the Kaoko Belt. (2) A sudden switch to E–W directed shortening at ∼508 Ma is interpreted as a far-field effect imposed on the Damara Orogenic System, most plausibly from arc obduction along the orogenic margin of Gondwana (Ross-Delamerian Orogen). (3) This imposed stress field established a N–S extension direction exploited by decompression melts, switch to vertical shortening, and triggered gravitational collapse and extension of the thermally weakened hot orogen core at ∼505 Ma, producing an extensional metamorphic core complex across the Central Zone