Numerically determined transport laws for fingering ("thermohaline") convection in astrophysics

We present the first three-dimensional simulations of fingering convection performed in a parameter regime close to the one relevant for astrophysics, and reveal the existence of simple asymptotic scaling laws for turbulent heat and compositional transport. These laws can straightforwardly be extrapolated to the true astrophysical regime. Our investigation also indicates that thermocompositional "staircases," a key consequence of fingering convection in the ocean, cannot form spontaneously in the fingering regime in stellar interiors. Our proposed empirically-determined transport laws thus provide simple prescriptions for mixing by fingering convection in a variety of astrophysical situations, and should, from here on, be used preferentially over older and less accurate parameterizations. They also establish that fingering convection does not provide sufficient extra mixing to explain observed chemical abundances in RGB stars.Comment: Submitted to ApJ Letters on October 29th. 15 pages, 4 figures. See Garaud 2010 for companion pape

Very long baseline interferometry observation of the triple AGN candidate J0849+1114

Context. In the hierarchical structure formation model, galaxies grow through various merging events. Numerical simulations indicate that mergers can enhance the activity of central supermassive black holes in galaxies. Aims. A system of three interacting galaxies, called J0849+1114, has recently been identified and multi-wavelength evidence of all three galaxies containing active galactic nuclei has recently been found. The system has substantial radio emission; we aim to investigate the origin of this radio emission with a high-resolution radio interferometric observation and to discover whether it is related to star formation or to one or more of the active galactic nuclei in the system. Methods. We performed high-resolution continuum observation of J0849+1114 with the European Very Long Baseline Interferometry Network at 1.7 GHz. Results. We detected one compact radio emitting source at the position of the easternmost nucleus. Its high brightness temperature and radio power indicate that the radio emission originates from a radio-emitting active galactic nucleus. Additionally, we found that significant amount of flux density is contained in ∼100 milliarcsec-scale feature related to the active nucleus

Prodsimplicial-Neighborly Polytopes

Simultaneously generalizing both neighborly and neighborly cubical polytopes, we introduce PSN polytopes: their k-skeleton is combinatorially equivalent to that of a product of r simplices. We construct PSN polytopes by three different methods, the most versatile of which is an extension of Sanyal and Ziegler's "projecting deformed products" construction to products of arbitrary simple polytopes. For general r and k, the lowest dimension we achieve is 2k+r+1. Using topological obstructions similar to those introduced by Sanyal to bound the number of vertices of Minkowski sums, we show that this dimension is minimal if we additionally require that the PSN polytope is obtained as a projection of a polytope that is combinatorially equivalent to the product of r simplices, when the dimensions of these simplices are all large compared to k.Comment: 28 pages, 9 figures; minor correction

Confirmation of the Planetary Microlensing Signal and Star and Planet Mass Determinations for Event OGLE-2005-BLG-169

We present Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3) observations of the source and lens stars for planetary microlensing event OGLE-2005-BLG-169, which confirm the relative proper motion prediction due to the planetary light curve signal observed for this event. This (and the companion Keck result) provide the first confirmation of a planetary microlensing signal, for which the deviation was only 2%. The follow-up observations determine the flux of the planetary host star in multiple passbands and remove light curve model ambiguity caused by sparse sampling of part of the light curve. This leads to a precise determination of the properties of the OGLE-2005-BLG-169Lb planetary system. Combining the constraints from the microlensing light curve with the photometry and astrometry of the HST/WFC3 data, we find star and planet masses of M_* = 0.69+- 0.02 M_solar and m_p = 14.1 +- 0.9 M_earth. The planetary microlens system is located toward the Galactic bulge at a distance of D_L = 4.1 +- 0.4 kpc, and the projected star-planet separation is a_perp = 3.5 +- 0.3 AU, corresponding to a semi-major axis of a = 4.0 (+2.2 -0.6) AU.Comment: 21 pages, including 5 figures, published in Ap

Silicon-organic hybrid electro-optical devices

Organic materials combined with strongly guiding silicon waveguides open the route to highly efficient electro-optical devices. Modulators based on the so-called silicon-organic hybrid (SOH) platform have only recently shown frequency responses up to 100 GHz, high-speed operation beyond 112 Gbit/s with fJ/bit power consumption. In this paper, we review the SOH platform and discuss important devices such as Mach-Zehnder and IQ-modulators based on the linear electro-optic effect. We further show liquid-crystal phase-shifters with a voltage-length product as low as V pi L = 0.06 V.mm and sub-mu W power consumption as required for slow optical switching or tuning optical filters and devices

Outcomes from a single-intervention trial to improve interprofessional practice behaviors at a student-led free clinic

Background Interprofessional collaboration (IPC) is the practice of two or more healthcare professionals working together and learning from one another to improve health outcomes. IPC is important for quality training, typically improving individual and group level outcomes. Students value the opportunity for leadership and teamwork development when IPC is offered in their curriculum. The Indiana University Student Outreach Clinic (IUSOC) is a student run clinic that provides free primary care services to underserved residents residing in Indianapolis, Indiana. The IUSOC partner leaders identified a need to enhance knowledge about partner roles, scope of practice, and professional training with the hopes of improving quality of care through IPC and utilization of clinic resources. Methods A cluster randomized design consisted of education session days and control days. Participants had an equal selection probability. Student partners from ten different disciplines were involved. Two survey instruments were used for data collection: 1) The Interprofessional Socialization and Valuing Scale and 2) The Professional Consciousness Raising Questionnaire. The former measured the attitudes and beliefs that underlie interprofessional socialization, while the latter assessed pre/post student knowledge of the roles and responsibilities of each partner. Results The control arm of the study was composed of 167 student participants and the intervention arm had 170 participants. Participants in the intervention arm had greater scores for “ability to work with others”, “value in working with others”, and “comfort in working with others.” The intervention arm also had significantly increased odds of correctly identifying the roles responsibilities of the nursing, law, dental, and global health disciplines. Conclusions Results of this study demonstrate that administering a short interprofessional education exercise to healthcare professional students leads to improved IPC through increased interprofessional knowledge about other professions and change in beliefs and values toward the value of interprofessional collaboration among healthcare professionals

The Big Ten IPE Academic Alliance: A regional approach to developing Interprofessional Education and practice

Interprofessional practice and education (IPE) efforts has greatly increased in the past few years, primarily through the leadership of several national and international organizations. These organizations have sponsored forums for information exchange and best practices, which has significantly influenced the development of programs across various educational institutions and practice environments. Several regional groups have emerged, organized around a common purpose and geographic proximity, to share ideas and implement new IPE programs across the cooperating organizations. This article describes the history and growth of one of the newer regional groups, the Big Ten IPE Academic Alliance. Included in this discussion is how the group was created, its governing structure and the various results of its efforts. The intent is to provide expanded guidance how to develop regional groups that are effective vehicles for the successful implementation of IPE within educational and health settings

Polytopality and Cartesian products of graphs

We study the question of polytopality of graphs: when is a given graph the graph of a polytope? We first review the known necessary conditions for a graph to be polytopal, and we provide several families of graphs which satisfy all these conditions, but which nonetheless are not graphs of polytopes. Our main contribution concerns the polytopality of Cartesian products of non-polytopal graphs. On the one hand, we show that products of simple polytopes are the only simple polytopes whose graph is a product. On the other hand, we provide a general method to construct (non-simple) polytopal products whose factors are not polytopal.Comment: 21 pages, 10 figure

50 Tbit/s Massively ParallelWDMTransmission in C and L Band Using Interleaved Cavity-Soliton Kerr Combs

Interleaving two soliton Kerr combs we generate 179 carriers for WDM transmission and demonstrate transmission of a data stream of 50 Tbit/s over 75 km. This is the highest data rate achieved with a chip-scale comb source

Silicon-Organic Hybrid (SOH) and Plasmonic-Organic Hybrid (POH) integration

Silicon-organic hybrid (SOH) and plasmonic-organic hybrid (POH) integration combines organic clectro-optic materials with silicon photonic and plasmonic waveguides, The concept enables fast and power-efficient modulators that support advanced modulation formats such as QPSK and 16QAM