A primal-dual semidefinite programming algorithm tailored to the variational determination of the two-body density matrix

The quantum many-body problem can be rephrased as a variational determination of the two-body reduced density matrix, subject to a set of N-representability constraints. The mathematical problem has the form of a semidefinite program. We adapt a standard primal-dual interior point algorithm in order to exploit the specific structure of the physical problem. In particular the matrix-vector product can be calculated very efficiently. We have applied the proposed algorithm to a pairing-type Hamiltonian and studied the computational aspects of the method. The standard N-representability conditions perform very well for this problem.Comment: 24 pages, 5 figures, submitted to the Journal of Computational Physic

Variational determination of the second-order density matrix for the isoelectronic series of beryllium, neon and silicon

The isoelectronic series of Be, Ne and Si are investigated using a variational determination of the second-order density matrix. A semidefinite program was developed that exploits all rotational and spin symmetries in the atomic system. We find that the method is capable of describing the strong static electron correlations due to the incipient degeneracy in the hydrogenic spectrum for increasing central charge. Apart from the ground-state energy various other properties are extracted from the variationally determined second-order density matrix. The ionization energy is constructed using the extended Koopmans' theorem. The natural occupations are also studied, as well as the correlated Hartree-Fock-like single particle energies. The exploitation of symmetry allows to study the basis set dependence and results are presented for correlation-consistent polarized valence double, triple and quadruple zeta basis sets.Comment: 19 pages, 7 figures, 3 tables v2: corrected typo in Eq. (52

Valorization of wheat bran agro-industrial byproduct as an upgrading filler for mycelium-based composite materials

When considered by a biorefinery approach, an agroindustrial byproduct such as wheat bran can find a new standing in the field of fabrication of mycelium-based materials. The present work reports on a systematic study on the effect of wheat bran as an upgrading feedstock for the growth and development of fully biobased and biodegradable composites. Two families of materials based on bran/cotton and bran/hemp mixtures were fabricated on an industrial scale. The natural materials thus obtained were fully characterized and their end-life was assessed in composting conditions. The research focusses on two main aspects: the nutritional contribution of bran for the fungal growth and its effect on the mechanical properties as a filler in the final composites. It must be noted that the valorization and exploitation of a byproduct such as bran can have a considerable impact on the industrial production of mycelium-based composite materials, by reducing the time of production while increasing their mechanical performances

The half-life of 221^{221}Fr in Si and Au at 4K and at mK temperatures

The half-life of the $\alpha$ decaying nucleus $^{221}$Fr was determined in different environments, i.e. embedded in Si at 4 K, and embedded in Au at 4 K and about 20 mK. No differences in half-life for these different conditions were observed within 0.1%. Furthermore, we quote a new value for the absolute half-life of $^{221}$Fr of t$_{1/2}$ = 286.1(10) s, which is of comparable precision to the most precise value available in literature

Harmoney : semantics for FinTech

As a result of legislation imposed by the European Parliament, in order to protect inhabitants from being exposed to a too high financial risk when investing in a variety of financial markets and products, Financial Service Providers (FSPs) are obliged to test the knowledge and experience of potential investors. This is oftemtimes done by means of questionnaires. However, these questionnaires differ in style and structure from one FSP to the other. The goal of this research is to manage in a more cost-effective manner (aligned with the needs and competencies of the individual financial investor in terms of products and services) the management of the private equity and to facilitate the fine-tuned personalised financial advisory services needed. This is achieved by means of a knowledge-based approach, integrating the available information of the investor (e.g. personal profile in terms of financial knowledge and experience) and for an extendable amount of financial service providers w ith their financial products and demonstrated by a number of exemplary use case scenarios

Valorization of Ferulic Acid from Agro-Industrial by-Products for Application in Agriculture

The use of bioplastic mulch in agriculture has increased dramatically in the last years throughout the world. Nowadays, biodegradable materials for mulching films strive to constitute a reliable and more sustainable alternative to classical materials such as polyethylene (PE). The main challenge is to improve their durability in the soil to meet the required service length for crop farming by using benign and sustainable antioxidant systems. Here, we report the design and fabrication of biodegradable materials based on polybutylene (succinate adipate) (PBSA) for mulching applications, incorporating a fully biobased polymeric antioxidant deriving from ferulic acid, which can be extracted from an industrial by-product. Poly-dihydro (ethylene ferulate) (PHEF) from ferulic acid was synthesized by a two-step polymerization process. It is characterized by improved thermal stability in comparison with ferulic acid monomer and therefore suitable for common industrial processing conditions. Different blends of PBSA and PHEF obtained by melt mixing or by reactive extrusion were prepared and analyzed to understand the effect of the presence of PHEF. The results demonstrate that PHEF, when processed by reactive extrusion, presents a remarkable antioxidant effect, even in comparison with commercial additives, preserving a high level of the mechanical properties of the PBSA matrix without affecting the biodegradable character of the blend

Ambient-aware continuous care through semantic context dissemination

Background: The ultimate ambient-intelligent care room contains numerous sensors and devices to monitor the patient, sense and adjust the environment and support the staff. This sensor-based approach results in a large amount of data, which can be processed by current and future applications, e. g., task management and alerting systems. Today, nurses are responsible for coordinating all these applications and supplied information, which reduces the added value and slows down the adoption rate. The aim of the presented research is the design of a pervasive and scalable framework that is able to optimize continuous care processes by intelligently reasoning on the large amount of heterogeneous care data. Methods: The developed Ontology-based Care Platform (OCarePlatform) consists of modular components that perform a specific reasoning task. Consequently, they can easily be replicated and distributed. Complex reasoning is achieved by combining the results of different components. To ensure that the components only receive information, which is of interest to them at that time, they are able to dynamically generate and register filter rules with a Semantic Communication Bus (SCB). This SCB semantically filters all the heterogeneous care data according to the registered rules by using a continuous care ontology. The SCB can be distributed and a cache can be employed to ensure scalability. Results: A prototype implementation is presented consisting of a new-generation nurse call system supported by a localization and a home automation component. The amount of data that is filtered and the performance of the SCB are evaluated by testing the prototype in a living lab. The delay introduced by processing the filter rules is negligible when 10 or fewer rules are registered. Conclusions: The OCarePlatform allows disseminating relevant care data for the different applications and additionally supports composing complex applications from a set of smaller independent components. This way, the platform significantly reduces the amount of information that needs to be processed by the nurses. The delay resulting from processing the filter rules is linear in the amount of rules. Distributed deployment of the SCB and using a cache allows further improvement of these performance results

A step counting hill climbing algorithm

This paper presents a new single-parameter local search heuristic named Step Counting Hill Climbing algorithm (SCHC). It is a very simple method in which the current cost serves as an acceptance bound for a number of consecutive steps. This is the only parameter in the method that should be set up by the user. Furthermore, the counting of steps can be organized in different ways; therefore the proposed method can generate a large number of variants and also extensions. In this paper, we investigate the behaviour of the three basic variants of SCHC on the university exam timetabling problem. Our experiments demonstrate that the proposed method shares the main properties with the Late Acceptance Hill Climbing method, namely its convergence time is proportional to the value of its parameter and a non-linear rescaling of a problem does not affect its search performance. However, our new method has two additional advantages: a more flexible acceptance condition and better overall performance. In this study we compare the new method with Late Acceptance Hill Climbing, Simulated Annealing and Great Deluge Algorithm. The Step Counting Hill Climbing has shown the strongest performance on the most of our benchmark problems used