From Six to Four and More: Massless and Massive Maximal Super Yang-Mills Amplitudes in 6d and 4d and their Hidden Symmetries

A self-consistent exposition of the theory of tree-level superamplitudes of the 4d N=4 and 6d N=(1,1) maximally supersymmetric Yang-Mills theories is provided. In 4d we work in non-chiral superspace and construct the superconformal and dual superconformal symmetry generators of the N=4 SYM theory using the non-chiral BCFW recursion to prove the latter. In 6d we provide a complete derivation of the standard and hidden symmetries of the tree-level superamplitudes of N=(1,1) SYM theory, again using the BCFW recursion to prove the dual conformal symmetry. Furthermore, we demonstrate that compact analytical formulae for tree-superamplitudes in N=(1,1) SYM can be obtained from a numerical implementation of the supersymmetric BCFW recursion relation. We derive compact manifestly dual conformal representations of the five- and six-point superamplitudes as well as arbitrary multiplicity formulae valid for certain classes of superamplitudes related to ultra-helicity-violating massive amplitudes in 4d. We study massive tree superamplitudes on the Coulomb branch of the N=4 SYM theory from dimensional reduction of the massless superamplitudes of the six-dimensional N=(1,1) SYM theory. We exploit this correspondence to construct the super-Poincare and enhanced dual conformal symmetries of massive tree superamplitudes in N=4 SYM theory which are shown to close into a finite dimensional algebra of Yangian type. Finally, we address the fascinating possibility of uplifting massless 4d superamplitudes to 6d massless superamplitudes proposed by Huang. We confirm the uplift for multiplicities up to eight but show that finding the uplift is highly non-trivial and in fact not of a practical use for multiplicities larger than five.Comment: 77 pages, 1 figure. v2: Reference adde

The relation between fluid intelligence and the general factor as a function of cultural background: a test of Cattell's investment theory

According to Cattell’s (1987) Investment theory individual differences in acquisition of knowledge and skills are partly the result of investment of Fluid Intelligence (Gf) in learning situations demanding insights in complex relations. If this theory holds true Gf will be a factor of General Intelligence (g) because it is involved in all domains of learning. The purpose of the current study was to test the Investment theory, through investigating effects on the relation between Gf and g of differential learning opportunities for different subsets of a population. A second-order model was fitted with confirmatory factor analysis to a battery of 17 tests hypothesized to measure four broad cognitive abilities The model was estimated for three groups with different learning opportunities (N = 2358 Swedes, N = 620 European immigrants, N = 591 non-European immigrants), as well as for the total group. For this group the g Gf relationship was 0.83, while it was close to unity within each of the three subgroups. These results support the Investment theory.Structure of intelligence; Cattell’s Investment theory; fluid Intelligence; general Intelligence

Estimation of Basic Reproduction Number of the COVID-19 Epidemic in Denmark using a Two-Step Model

Objective: To conduct an early estimation of the Basic Reproduction Number (BRN) induced by government interference, and to project resulting day to day number of in-patients, ICU-patients and cumulative number of deaths in a Danish setting. Method: We used the Kermack and McKendrick model with varying basic reproduction number to estimate number infected and age stratified percentages to estimate number of in-patients, ICU-patients and cumulative number of deaths. Changes in basic reproduction number was estimated based on current in-patient numbers. Results: The basic reproductive number in the time period of February 27th to March 18th was found to be 2.65, however, this number was reduced to 1.99 after March 18th. Keywords: COVID-19, basic reproduction number, Danish populatio

Comparison of two selected test methods for assessment of dynamic viscosity of bituminous binders

Dynamická viskozita je jednou z hlavních charakteristik asfaltového pojiva a jeho aplikace v asfaltových směsích. Viskozitu lze využít pro predikci tokového chování a pro stanovení úrovně zpracovatelnosti a zhutnění. Jelikož asfaltové pojivo je viskoelastický materiál, není stanovení dynamické viskozity jednoduché jako v případě Newtonovské kapaliny. Známé a v praxi využívané jsou různé metody jejího stanovení, dnes nejčastěji s využitím rotačního Brookfield viskozimetru. Uvažovat lze i další metody, přičemž nejsou ověřené závislosti výsledků různých metod. Příspěvek se zaměřuje především na zkoušku s využitím rotačního viskozimetru a zkoušku stanovení dynamické viskozity na dynamickém smykovém reometru s využitím geometrie destička-destička ve zkušebním režimu s řízenou rotací. Provedena byla vzájemná porovnání a posouzení možných závislostí obou přístupů z hlediska pozdějšího využití v praxi i při experimentálním posuzování. Cílem bylo identifikovat a odvodit možné závislosti mezi oběma metodami. V rámci získaných výsledků byla pozornost též věnována porovnání změny dynamické viskozity u nezestárlých a zestárlých asfaltových pojiv z důvodu určujícího dopadu fenoménu stárnutí na degradaci materiálu a tudíž trvanlivost asfaltové směsi. Jako dodatečný výsledek byl posouzen vliv některých používaných přísad na viskozitu asfaltového pojiva.Dynamic viscosity is one of the key characteristics related to bitumen and its use in asphalt mixes. Viscosity is in this connection used for prediction of flow behavior and determination of good workability and compaction. Since bitumen is a viscoelastic material the determination of dynamic viscosity is not as simple as for Newtonian fluid. Different test methods are know and used, most commonly rotation Brookfield viscosimeter. Applicable are also other test methods, nevertheless assessed functionalities of results from different test methods are not described exactly. The paper describes in this connection application of rotation viscosity test and use of dynamic shear rheometer with plate-plate geometry in a rotational test. Mutual comparison of possible functionalities of both approaches for later use in laboratory and application in practice are made. Within the scope of gained results further assessment has been done as well for the comparison of dynamic viscosity of un-aged and aged bituminous binders, because of the crucial impact of ageing as one of the key effects of material degradation. Influence of selected additives on bitumen viscosity has been analyzed as well

A multi-agent platform for auction-based allocation of loads in transportation logistics

This paper describes an agent-based platform for the allocation of loads in distributed transportation logistics, developed as a collaboration between CWI, Dutch National Center for Mathematics and Computer Science, Amsterdam and Vos Logistics Organizing, Nijmegen, The Netherlands. The platform follows a real business scenario proposed by Vos, and it involves a set of agents bidding for transportation loads to be distributed from a central depot in the Netherlands to different locations across Germany. The platform supports both human agents (i.e. transportation planners), who can bid through specialized planning and bidding interfaces, as well as automated, software agents. We exemplify how the proposed platform can be used to test both the bidding behaviour of human logistics planners, as well as the performance of automated auction bidding strategies, developed for such settings. The paper first introduces the business problem setting and then describes the architecture and main characteristics of our auction platform. We conclude with a preliminary discussion of our experience from a human bidding experiment, involving Vos planners competing for orders both against each other and against some (simple) automated strategies