Almahata Sitta (=asteroid 2008 TC3) and the search for the ureilite parent body

This article explores what the recovery of 2008 TC3 in the form of the Almahata Sitta meteorites may tell us about the source region of ureilites in the main asteroid belt. An investigation is made into what is known about asteroids with roughly the same spectroscopic signature as 2008 TC3. A population of low-inclination near-Earth asteroids is identified with spectra similar to 2008 TC3. Five asteroid families in the Main Belt, as well as a population of ungrouped asteroids scattered in the inner and central belts, are identified as possible source regions for this near-Earth population and 2008 TC3. Three of the families are ruled out on dynamical and spectroscopic grounds. New near-infrared spectra of 142 Polana and 1726 Hoffmeister, lead objects in the two other families, also show a poor match to Almahata Sitta. Thus, there are no Main Belt spectral analogs to Almahata Sitta currently known. Space weathering effects on ureilitic materials have not been investigated, so that it is unclear how the spectrum of the Main Belt progenitor may look different from the spectra of 2008 TC3 and the Almahata Sitta meteorites. Dynamical arguments are discussed, as well as ureilite petrogenesis and parent body evolution models, but these considerations do not conclusively point to a source region either, other than that 2008 TC3 probably originated in the inner asteroid belt.

Finding Merit in Judicial Appointments: NIJAC and the Search for a New Judiciary in Northern Ireland

The post-Agreement constitutional architecture has produced a new legal space in Northern Ireland. While the court structure has largely endured in a recognisable format there are perhaps now new expectations of how it will function in the next stage of Northern Ireland’s transition from a society in conflict. These expectations come into focus around the nature and role of the judiciary that is to oversee this new legal space. At the same time there are other, wider forces pressing upon the judiciary across the United Kingdom and these are being acted out in the various appointment commissions and regimes that have been created to modernise the judiciary. This all contributes to establishing a dynamic context for considering whether and/or how the judiciary in Northern Ireland is changing, and the forces that may be conditioning any change. This chapter looks at some of the expectations that might arise for the judiciary. It focuses both on some ideas about what might be the role of a judge in a transitional context, and the debate about how judges generally should be appointed across the United Kingdom where the idea of “merit” emerges as governing concept. Next consideration is given to how this idea of merit plays out in the Northern Ireland context and, in particular, how it impacts on the appointment of women to senior judicial roles which has emerged as the central concern in the new dispensation. Here the chapter draws on two pieces of research: the first looking at the issues surrounding judicial appointments and attitudes towards seeking such posts in the Northern Ireland context, and a second project where the idea of “merit” as a governing factor in judicial appointment was further explored in focus groups and interviews. Finally the chapter looks ahead at the challenges around judicial appointment that remain and suggests that notion of ‘merit’ has not provided the robust foundation which its proponents imagined it would.

Search for a New International System

The crisis in Ukraine has three separate but closely linked causes, which must be understood before any long-term solution is found. The three causes are unstable post-Soviet borders, Ukrainian difficulties in state- and nation- building, and Russia’s frustration with the post-Cold War status quo, believes Dr Alexander Titov, who insists that the search for a new international system is taking shape through this current crisis in Europe

A hybrid harmony search with arithmetic crossover operation for economic dispatch

Economic dispatch (ED) problems often exhibit non-linear, non-convex characteristics due to the valve point effects. Further, various constraints and factors, such as prohibited operation zones, ramp rate limits and security constraints imposed by the generating units, and power loss in transmission make it even more challenging to obtain the global optimum using conventional mathematical methods. Meta-heuristic approaches are capable of solving non-linear, non-continuous and non-convex problems effectively as they impose no requirements on the optimization problems. However, most methods reported so far mainly focus on a specific type of ED problems, such as static or dynamic ED problems. This paper proposes a hybrid harmony search with arithmetic crossover operation, namely ACHS, for solving five different types of ED problems, including static ED with valve point effects, ED with prohibited operating zones, ED considering multiple fuel cells, combined heat and power ED, and dynamic ED. In this proposed ACHS, the global best information and arithmetic crossover are used to update the newly generated solution and speed up the convergence, which contributes to the algorithm exploitation capability. To balance the exploitation and exploration capabilities, the opposition based learning (OBL) strategy is employed to enhance the diversity of solutions. Further, four commonly used crossover operators are also investigated, and the arithmetic crossover shows its efficiency than the others when they are incorporated into HS. To make a comprehensive study on its scalability, ACHS is first tested on a group of benchmark functions with a 100 dimensions and compared with several state-of-the-art methods. Then it is used to solve seven different ED cases and compared with the results reported in literatures. All the results confirm the superiority of the ACHS for different optimization problems.

An efficient harmony search with new pitch adjustment for dynamic economic dispatch

A simple yet efficient harmony search (HS) method with a new pitch adjustment rule (NPAHS) is proposed for dynamic economic dispatch (DED) of electrical power systems, a large-scale non-linear real time optimization problem imposed by a number of complex constraints. The new pitch adjustment rule is based on the perturbation information and the mean value of the harmony memory, which is simple to implement and helps to enhance solution quality and convergence speed. A new constraint handling technique is also developed to effectively handle various constraints in the DED problem, and the violation of ramp rate limits between the first and last scheduling intervals that is often ignored by existing approaches for DED problems is effectively eliminated. To validate the effectiveness, the NPAHS is first tested on 10 popular benchmark functions with 100 dimensions, in comparison with four HS variants and five state-of-the-art evolutionary algorithms. Then, NPAHS is used to solve three 24-h DED systems with 5, 15 and 54 units, which consider the valve point effects, transmission loss, emission and prohibited operating zones. Simulation results on all these systems show the scalability and superiority of the proposed NPAHS on various large scale problems.

Query Suggestions for Textual Problem Solution Repositories

Textual problem-solution repositories are available today in
various forms, most commonly as problem-solution pairs from community
question answering systems. Modern search engines that operate on
the web can suggest possible completions in real-time for users as they
type in queries. We study the problem of generating intelligent query
suggestions for users of customized search systems that enable querying
over problem-solution repositories. Due to the small scale and specialized
nature of such systems, we often do not have the luxury of depending on
query logs for finding query suggestions. We propose a retrieval model
for generating query suggestions for search on a set of problem solution
pairs. We harness the problem solution partition inherent in such
repositories to improve upon traditional query suggestion mechanisms
designed for systems that search over general textual corpora. We evaluate
our technique over real problem-solution datasets and illustrate that
our technique provides large and statistically significant

Real-space grids and the Octopus code as tools for the development of new simulation approaches for electronic systems

Real-space grids are a powerful alternative for the simulation of electronic systems. One of the main advantages of the approach is the flexibility and simplicity of working directly in real space where the different fields are discretized on a grid, combined with competitive numerical performance and great potential for parallelization. These properties constitute a great advantage at the time of implementing and testing new physical models. Based on our experience with the Octopus code, in this article we discuss how the real-space approach has allowed for the recent development of new ideas for the simulation of electronic systems. Among these applications are approaches to calculate response properties, modeling of photoemission, optimal control of quantum systems, simulation of plasmonic systems, and the exact solution of the Schrödinger equation for low-dimensionality systems.

The HARPS-N Rocky Planet Search. I. HD 219134 b: A transiting rocky planet in a multi-planet system at 6.5 pc from the Sun

We know now from radial velocity surveys and transit space missions thatplanets only a few times more massive than our Earth are frequent aroundsolar-type stars. Fundamental questions about their formation history,physical properties, internal structure, and atmosphere composition are,however, still to be solved. We present here the detection of a systemof four low-mass planets around the bright (V = 5.5) and close-by (6.5pc) star HD 219134. This is the first result of the Rocky Planet Searchprogramme with HARPS-N on the Telescopio Nazionale Galileo in La Palma.The inner planet orbits the star in 3.0935 ± 0.0003 days, on aquasi-circular orbit with a semi-major axis of 0.0382 ± 0.0003AU. Spitzer observations allowed us to detect the transit of the planetin front of the star making HD 219134 b the nearest known transitingplanet to date. From the amplitude of the radial velocity variation(2.25 ± 0.22 ms-1) and observed depth of the transit(359 ± 38 ppm), the planet mass and radius are estimated to be4.36 ± 0.44 M⊕ and 1.606 ± 0.086R⊕, leading to a mean density of 5.76 ± 1.09 gcm-3, suggesting a rocky composition. One additional planetwith minimum-mass of 2.78 ± 0.65 M⊕ moves on aclose-in, quasi-circular orbit with a period of 6.767 ± 0.004days. The third planet in the system has a period of 46.66 ± 0.08days and a minimum-mass of 8.94 ± 1.13 M⊕, at0.233 ± 0.002 AU from the star. Its eccentricity is 0.46 ±0.11. The period of this planet is close to the rotational period of thestar estimated from variations of activity indicators (42.3 ± 0.1days). The planetary origin of the signal is, however, thepreferredsolution as no indication of variation at the corresponding frequency isobserved for activity-sensitive parameters. Finally, a fourth additionallonger-period planet of mass of 71 M⊕ orbits the starin 1842 days, on an eccentric orbit (e = 0.34 ± 0.17) at adistance of 2.56 AU.The photometric time series and radial velocities used in this work areavailable in electronic form at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr(ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/584/A72