On the Singularities of the Magnon S-matrix

We investigate the analytic structure of the magnon S-matrix in the spin-chain description of planar ${\cal N}=4$ SUSY Yang-Mills/$AdS_{5}\times S^{5}$ strings. Semiclassical analysis suggests that the exact S-matrix must have a large family of poles near the real axis in momentum space. In this article we show that these are double poles corresponding to the exchange of pairs of BPS magnons. Their locations in the complex plane are uniquely fixed by the known dispersion relation for the BPS particles. The locations precisely agree with the recent conjecture for the $S$ matrix by Beisert, Hernandez, Lopez, Eden and Staudacher (hep-th/0609044 and hep-th/0610251). These poles do not signal the presence of new bound states. In fact, a certain non-BPS localized classical solution, which was thought to give rise to new bound states, can actually decay into a pair of BPS magnons.Comment: 40 pages, 14 figures; typos corrected, references adde

Projectrapportage Cooperatief pootvis productiecentrum voor de Nederlandse mariene viskweek sector

Het doel van dit project is het demonstreren van de haalbaarheid van een coöperatief productiecentrum voor tarbot en tong pootvis ten behoeve van de Nederlandse platviskweek sector. De rapportage gaat voornamelijk in op de kennisvragen m.b.t. de kosten en de technische haalbaarheid van een pootvis productiesysteem

On Central Charges and Hamiltonians for 0-brane dynamics

We consider general properties of central charges of zero branes and associated duality invariants, in view of their double role, on the bulk and on the world volume (quantum-mechanical) theory. A detailed study of the BPS condition for the mass spectrum arising from toroidal compactifications is given for 1/2, 1/4 and 1/8 BPS states in any dimensions. As a byproduct, we retreive the U-duality invariant conditions on the charge (zero mode) spectrum and the orbit classification of BPS states preserving different fractions of supersymmetry. The BPS condition for 0-branes in theories with 16 supersymmetries in any dimension is also discussed.Comment: 23 pages, latex fil

Multi-Fuel Burner Systems for Industrial Applications

Multi-fuel firing systems are used in several industrial processes such as in power stations, drying mills and metallurgical plants as well as in rotary kiln systems, industrial boilers, cogeneration plants and various thermal process factories. Such systems should being not only able to utilize different fuel types, but also to respond flexible due to changing in fuel compositions and qualities. In particular the ignition, stability and pollutant problems must be taken into account. That means that these systems should fulfill the operational parameters and ecological target according to German Technical Instructions on Air Quality Control TA Luft 2002. The Operation of these so called multi fuels systems is determined on the one hand by the conditions of the start-up procedure (e. g. drying of the refractory material, creation of the necessary operating environment) and on the other hand by the process-related requirements, fluctuating commodity prices, unstable fuel supplies and the use of internally resulting production scrap. In this paper two multi-fuel burner systems are selected from the extensive Brinkman’s production program to be shown in details. These are combined combustion systems for «pulverized coal-gas» and «pulverized coal-oil», respectively.Многотопливные горелочные системы используются в различных промышленных процессах, на ТЭС и в металлургии, включая сухое измельчение сырых материалов, во вращающихся печах, промышленных котлах, установках когенерации и специальных термических технологиях. Соответствующие системы должны быть пригодны для использования различных видов топлива и гибко реагировать на изменения его состава и качества, в частности, необходимо учитывать устойчивость воспламенения топливной смеси и сопутствующее загрязнение окружающей среды. Такие системы должны обеспечивать эксплуатационные параметры и экологические нормативы в соответствии с германскими техническими стандартами качества воздуха (TA Luft 2002 г.). Качество работы этих многотопливных систем определяется, с одной стороны, пусковыми условиями (например, сушка огнеупоров, создание требуемой рабочей среды), с другой стороны, эксплуатационными требованиями, колебаниями цен на сырьевые продукты и готовые товары, а также условиями, учитывающими специфику технологии, нестабильное снабжение топливом. Принимается во внимание также внутренняя утилизация отходов в пределах производства. В статье рассмотрены две многотопливные горелочные системы, выбранные из обширной производственной номенклатуры ООО «Бринкман». Соответственно представлены системы комбинированного сжигания пылеугольного и газового топлива, а также пылеугольного топлива с жидким топливом.Багатопаливні пальникові системи використовуються у різних промислових процесах, на ТЕС та у металургії включно з сухим подрібненням вологих матеріалів у обертових пічах, промислових котлах, установках когенерації та спеціальних термічних технологіях. Відповідні системи мають бути придатними для використання різних видів палива та гнучко реагувати на зміни його складу та якості, зокрема необхідно враховувати стійкість займання паливної суміші та супутнє забруднення довкілля. Такі системи мають забезпечувати експлуатаційні параметри та екологічні нормативи у відповідності до германських технічних стандартів щодо якості повітря (TA Luft 2002 р.). Якість роботи цих багатопаливних систем визначається пусковими умовами (наприклад, сушіння вогнетрив ів, створення потрібного робочого середовища) та, експлуатаційними вимогами, коливаннями цін на сировинні продукти та готові товари, а також умовами, що враховують специфіку технології, нестабільне постачання палива. Приймається до уваги також внутрішня утилізація відходів у межах виробництва. Розглянуто дві багатопаливні пальникові системи, вибрані з великої виробничої номенклатури ТОВ «Брінкман». Представлено системи комбінованого спалювання пиловугільного та газового палива, а також пиловугільного палива з рідким паливом

Water demand forecasting accuracy and influencing factors at different spatial scales using a Gradient Boosting Machine

Understanding, comparing, and accurately predicting water demand at different spatial scales is an important goal that will allow effective targeting of the appropriate operational and conservation efforts under an uncertain future. This study uses data relating to water consumption available at the household level, as well as postcode locations, household characteristics, and weather data in order to identify the relationships between spatial scale, influencing factors, and forecasting accuracy. For this purpose, a Gradient Boosting Machine (GBM) is used to predict water demand 1–7 days into the future. Results show an exponential decay in prediction accuracy from a Mean Absolute Percentage Error (MAPE) of 3.2% to 17%, for a reduction in group size from 600 to 5 households. Adding explanatory variables to the forecasting model reduces the MAPE up to 20% for the peak days and smaller household groups (20–56 households), whereas for larger aggregations of properties (100–804 households), the range of improvement is much smaller (up to 1.2%). Results also show that certain types of input variables (past consumption and household characteristics) become more important for smaller aggregations of properties, whereas others (weather data) become less important.Sanitary Engineerin

Facilitating Access to Justice in the Area of Economic Competition Protection

The relevance of the study is determined by the fact that all types of competitive relations should be affected in the formation of business development programs and be based on the adoption of appropriate decisions by all parties of economic relations. The novelty of the study is determined by the fact that each of the participants in economic relations in some cases cannot receive concomitant protection, which is based on equal access to the functions and organs of justice, which are provided by public authorities as carriers of justice. The practical significance of the study is determined by ensuring fair competition to form the prerequisites for the development of the social environment

Tachyon Condensation on Noncommutative Torus

We discuss noncommutative solitons on a noncommutative torus and their application to tachyon condensation. In the large B limit, they can be exactly described by the Powers-Rieffel projection operators known in the mathematical literature. The resulting soliton spectrum is consistent with T-duality and is surprisingly interesting. It is shown that an instability arises for any D-branes, leading to the decay into many smaller D-branes. This phenomenon is the consequence of the fact that K-homology for type II von Neumann factor is labeled by R.Comment: LaTeX, 17 pages, 1 figur

Canonical Quantization of Open String and Noncommutative Geometry

We perform canonical quantization of open strings in the $D$-brane background with a $B$-field. Treating the mixed boundary condition as a primary constraint, we get a set of secondary constraints. Then these constraints are shown to be equivalent to orbifold conditions to be imposed on normal string modes. These orbifold conditions are a generalization of the familiar orbifold conditions which arise when we describe open strings in terms of closed strings. Solving the constraints explicitly, we obtain a simple Hamiltonian for the open string, which reveals the nature of noncommutativity transparently.Comment: 14 pages, RevTex, added reference

Influences of deep learning, need for cognition and preparation time on open- and closed-book test performance

Objectives The ability to master discipline-specific knowledge is one of the competencies medical students must acquire. In this context, 'mastering' means being able to recall and apply knowledge. A way to assess this competency is to use both open- and closed-book tests. Student performance on both tests can be influenced by the way the student processes information. Deep information processing is expected to influence performance positively. The personal preferences of students in relation to how they process information in general (i.e. their level of need for cognition) may also be of importance. In this study, we examined the inter-relatedness of deep learning, need for cognition and preparation time, and scores on open- and closed-book tests. Methods This study was conducted at the University Medical Centre Groningen. Participants were Year 2 students (n = 423). They were asked to complete a questionnaire on deep information processing, a scale for need for cognition on a questionnaire on intellectualism and, additionally, to write down the time they spent on test preparation. We related these measures to the students' scores on two tests, both consisting of open- and closed-book components and used structural equation modelling to analyse the data. Results Both questionnaires were completed by 239 students (57%). The results showed that need for cognition positively influenced both open- and closed-book test scores (beta-coefficients 0.05 and 0.11, respectively). Furthermore, study outcomes measured by open-book tests predicted closed-book test results better than the other way around (beta-coefficients 0.72 and 0.11, respectively). Conclusions Students with a high need for cognition performed better on open- as well as closed-book tests. Deep learning did not influence their performance. Adding open-book tests to the regularly used closed-book tests seems to improve the recall of knowledge that has to be known by heart. Need for cognition may provide a valuable addition to existing theories on learning

Emergent Gravity from Noncommutative Spacetime

We showed before that self-dual electromagnetism in noncommutative (NC) spacetime is equivalent to self-dual Einstein gravity. This result implies a striking picture about gravity: Gravity can emerge from electromagnetism in NC spacetime. Gravity is then a collective phenomenon emerging from gauge fields living in fuzzy spacetime. We elucidate in some detail why electromagnetism in NC spacetime should be a theory of gravity. In particular, we show that NC electromagnetism is realized through the Darboux theorem as a diffeomorphism symmetry G which is spontaneously broken to symplectomorphism H due to a background symplectic two-form $B_{\mu\nu}=(1/\theta)_{\mu\nu}$, giving rise to NC spacetime. This leads to a natural speculation that the emergent gravity from NC electromagnetism corresponds to a nonlinear realization G/H of the diffeomorphism group, more generally its NC deformation. We also find some evidences that the emergent gravity contains the structure of generalized complex geometry and NC gravity. To illuminate the emergent gravity, we illustrate how self-dual NC electromagnetism nicely fits with the twistor space describing curved self-dual spacetime. We also discuss derivative corrections of Seiberg-Witten map which give rise to higher order gravity.Comment: 50 pages; Cosmetic revision and updated reference