Stabilization of solitons of the multidimensional nonlinear Schrodinger equation: Matter-wave breathers

We demonstrate that stabilization of solitons of the multidimensional Schrodinger equation with a cubic nonlinearity may be achieved by a suitable periodic control of the nonlinear term. The effect of this control is to stabilize the unstable solitary waves which belong to the frontier between expanding and collapsing solutions and to provide an oscillating solitonic structure, some sort of breather-type solution. We obtain precise conditions on the control parameters to achieve the stabilization and compare our results with accurate numerical simulations of the nonlinear Schrodinger equation. Because of the application of these ideas to matter waves these solutions are some sort of matter breathers

Bullion production in imperial China and its significance for sulphide ore smelting world-wide

Gold and silver production was of major importance for almost all ancient societies but has been rarely studied archaeologically. Here we present a reconstruction of a previously undocumented technology used to recover gold, silver and lead at the site of Baojia in Jiangxi province, China dated between the 7th and 13th centuries AD. Smelting a mixture of sulphidic and gossan ores in a relatively low temperature furnace under mildly reducing conditions, the process involved the use of metallic iron to reduce lead sulphide to lead metal, which acted as the collector of the precious metals. An experimental reconstruction provides essential information, demonstrating both the significant influence of sulphur on the silicate slag system, and that iron reduction smelting of lead can be carried out at a relatively low temperature. These new findings are relevant for further studies of lead and precious metal smelting slags world-wide. The technological choices of ancient smelters at this site are then discussed in their specific geographical and social-economic settings

Generalized Slow Roll Conditions and the Possibility of Intermediate Scale Inflation in Scalar-Tensor Theory

Generalized slow roll conditions and parameters are obtained for a general form of scalar-tensor theory (with no external sources), having arbitrary functions describing a nonminimal gravitational coupling F(\phi), a Kahler-like kinetic function k(\phi), and a scalar potential V(\phi). These results are then used to analyze a simple toy model example of chaotic inflation with a single scalar field \phi and a standard Higgs potential and a simple gravitational coupling function. In this type of model inflation can occur with inflaton field values at an intermediate scale of roughly 10^{11} GeV when the particle physics symmetry breaking scale is approximately 1 TeV, provided that the theory is realized within the Jordan frame. If the theory is realized in the Einstein frame, however, the intermediate scale inflation does not occur.Comment: 14 pages, no figs. Accepted to Classical and Quantum Gravit

Statistical Differences in Set Analysis in Badminton at the RIO 2016 Olympic Games

The aim of the present study was to determine statistical differences in a set of badminton competition matches in five different modalities with regard to competition level (Group Phase vs. Eliminatory Phase). Data from 453 sets (125 in men's singles; 108 sets in women's singles; 77 sets in men's doubles; 73 in women's doubles and 70 in mixed doubles) from the RIO 2016 Olympics Games were recorded and classified in two groups of variables to analyze variables related to match (5) and set (15). A descriptive analysis and univariate test (Mann-Whitney U) for non-parametric data were conducted. The results show in men's and women's singles all the variables related to match were higher in the Elimination Phase than in the Group Phase (p < 0.01). In Sets 1 and 3, the longest set duration, rally and average rally were found in the Elimination Phase than Group Stage (p < 0.05). In women's singles, these differences were also recorded in Set 2. For doubles, the results are more stable among groups. Men's doubles had a longer duration of the match and set (sets 1 and set 2) (p < 0.01), and also scored highest for average rally strokes (sets 1 3) < 0.05) and shuttles used in the Elimination Phase vs. the Group Phase along the match (p < 0.01). In women's doubles, more shuttles were used in a match in the Elimination than in the Group Phase. Moreover, the same results are established for Set 2, including for average rally. Mixed doubles saw no match going to three sets. However, the greatest differences showed a longer rally and average rally being registered in the Elimination than in the Group Phase. In conclusion, the timing factors of the badminton singles and doubles games were different in the Elimination and Group Phases. This information may help players and coaches prepare and administer different types of workouts or, more specifically, competition schedules adapted to the characteristics of modern badminton

Bloomery iron smelting in the Daye County (Hubei): Technological traditions in Qing China

China is widely accepted as the birthplace and shrine of the blast furnace, with bloomery iron technology largely believed to be scant before the Han Dynasty, and virtually inexistent afterwards. Challenging this traditional picture, this paper presents the material characterisation and reverse engineering of the primary smelting of bloomery iron at five metal production sites, located in close proximity of each other in the Daye County in Hubei Province, China, and in operation during the middle Qing Dynasty. A combination of materials science analyses–optical microscopy, SEM-EDS and WD-XRF–of surface collected technical material such as slags, furnace remains, and ores has demonstrated the established existence of bloomery iron at the core of the Chinese Empire. The five case studies present robust evidence of an overall broadly shared technical procedure based on the smelting of high grade ores in batteries of embanked furnaces, generating abundant slag but a limited metal output. The reconstruction of the various smelting processes in a relatively small region illustrates different technological adaptations to natural resources and socio-technological contexts, which are discussed using conceptual frameworks of rational economy and technological traditions.This paper is based on the PhD dissertation undertaken by David Larreina-Garcia at the UCL Institute of Archaeology, under the primary supervision of Marcos Martinón-Torres, carried out with the financial support of a UCL Impact Scholarship funded by UCL, the Institute for Archaeo-Metallurgical Studies (IAMS) and the Rio Tinto Group. Radiocarbon dates were obtained through the NERC/AHRC radiocarbon service (grant n° NF/2014/2/12)

Adaptability and Procedural Content Generation for Educational Escape Rooms

We present a literature review that aims to understand the role of the Educational Escape Room (EER) in improving the teaching, learning, and assessment processes through an EER design framework. The main subject is to identify the recent interventions in this field in the last five years. Our study focuses on understanding how it is possible to create an EER available to all students, namely visually challenged users. As a result of the implementation of new learning strategies that promote autonomous learning, a concern arose in adapting educational activities to each student's individual needs. To study the adaptability of each EER, we found the EER design framework essential to increase the student experience by promoting the consolidation of knowledge through narrative and level design. The results of our study show evidence of progress in students' performance while playing an EER, revealing that students' learning can be effective. Research on Procedural Content Generation (PCG) highlighted how important it is to implement adaptability in future studies of EERs. However, we found some limitations regarding the process of evaluating learning through the EERs, showing how important it is to study and implement learning analytics in future studies in this field

Do altmetrics promote Open Access? An exploratory analysis on altmetric differences between types of access in the field of Physics

The promotion of Open Science needs new metrics that encourage openness in scientific practices, and can help institutions to monitor it. In 2017, the European Commission (EC) created an Expert Group with the task of informing the commission on the possibility of including altmetric indicators as potential metrics that could foster and monitor open science advancements, but it failed to show how these metrics can help to foster Open Science. The current paper analyses differences in altmetric scores between Green OA publications, Gold OA publications and non OA publications. The goal of the paper is to empirically study whether altmetric indicators reinforce Open Access practices regardless of the type of access. We report a preliminary analysis based on two Physics journals. Our results show that gold OA documents are best covered in Altmetric.com and receive higher mentions than documents with other types of access. This is especially troublesome in the case of green OA, as it reflects that altmetric indicators do promote a very specific type of access closely linked with the publishing industry