Volume element structure and roton-maxon-phonon excitations in superfluid helium beyond the Gross-Pitaevskii approximation

We propose a theory which deals with the structure and interactions of volume elements in liquid helium II. The approach consists of two nested models linked via parametric space. The short-wavelength part describes the interior structure of the fluid element using a non-perturbative approach based on the logarithmic wave equation; it suggests the Gaussian-like behaviour of the element's interior density and interparticle interaction potential. The long-wavelength part is the quantum many-body theory of such elements which deals with their dynamics and interactions. Our approach leads to a unified description of the phonon, maxon and roton excitations, and has noteworthy agreement with experiment: with one essential parameter to fit we reproduce at high accuracy not only the roton minimum but also the neighboring local maximum as well as the sound velocity and structure factor.Comment: 9 pages, 6 figure

Surface state atoms and their contribution to the surface tension of quantum liquids

We investigate the new type of excitations on the surface of liquid helium. These excitations, called surfons, appear because helium atoms have discrete energy level at the liquid surface, being attracted to the surface by the van der Waals force and repulsed at a hard-core interatomic distance. The concentration of the surfons increases with temperature. The surfons propagate along the surface and form a two-dimensional gas. Basing on the simple model of the surfon microscopic structure, we estimate the surfon activation energy and effective mass for both helium isotopes. We also calculate the contribution of the surfons to the temperature dependence of the surface tension. This contribution explains the great and long-standing discrepancy between theory and experiment on this temperature dependence in both helium isotopes. The achieved agreement between our theory and experiment is extremely high. The comparison with experiment allows to extract the surfon activation energy and effective mass. The values of these surfon microscopic parameters are in a reasonable agreement with the calculated from the proposed simple model of surfon structure.Comment: 10 pages, 6 figure

Understanding the political motivations that shape Rwanda’s emergent developmental state

Twenty years after its horrific genocide, Rwanda has become a model for economic development. At the same time, its government has been criticized for its authoritarian tactics and use of violence. Missing from the often-polarized debate are the connections between these two perspectives. Synthesizing existing literature on Rwanda in light of a combined year of fieldwork, we argue that the GoR is using the developmental infrastructure to deepen state power and expand political control. We first identify the historical pressures that have motivated the Rwanda Patriotic Front (RPF) to re-imagine the political landscape. Sectarian unrest, political rivalry, wider regional insecurity, and aid withdrawal have all pressured the RPF to identify growth as strategic. However, the country’s political transformation extends beyond a prioritisation of growth and encompasses the reordering of the social and physical layout of the territory, the articulation of new ideologies and mindsets, and the provision of social services and surveillance infrastructure. Growth and social control go hand in hand. As such, the paper’s main contribution is to bring together the two sides of the Rwandan debate and place the country in a broader sociological literature about the parallel development of capitalist relations and transformations in state power

Track A Basic Science

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138319/1/jia218438.pd

Building a peaceful and sustainable future : democratic governance, decentralization and reconstruction in Southern Africa; final narrative report

Cara Produksipangan yang Baikmerupakanhalpenting yang harusdilakukandalamsebuahindustriyangdilakukanpadasampelhome industrykerupuk yang ada di Kota Cimahi. Tujuanpenelitianiniadalahuntukmendapatkaninformasimengenaicaraproduksipangan yang baikpadahome industry kerupuk di Kota Cimahi di bagianluar, dalamdanhasilproduksi. Alasandaridilakukannyapenelitianiniadalahberdasarkanhasilobservasi yang dilakukanpenelitipadabeberapahome industry kerupuk di Kota Cimahibahwamasihterdapatcarapengolahan yang tidakhigine, lingkungan yang tidakbersih, sertamenggunakanalat yang tidakdiperuntukanuntukpengolahanpangan. Metode yang digunakandalampenelitianiniadalahdeskriptifdenganpendekatanexplanatory sequential mixed methods design (rancanganmetodecampuransekuensialeksplanatoris). Metodecampuransekuensialeksplanatorisadalahcaramengumpulkan data kuantitatifdankualitatifdalamduafase, dengansalahsatubentuk data mengikutidanmemberikaninformasipadabentuk data pengumpulanlainnya. Dalampenelitianini data kualitatifakanmenguatkan data kuantitaif. Temuandalampenelitianiniadalahmasihditemukannyakriteriadalamindikator yang belumditerapkanolehsampelsebagaihome industry kerupuk di Kota Cimahi. Penerapancaraproduksipangan yang baikdalambagianluarproduksisudahlebihdarisetengahnyaditerapkanyaitusebesar 63%, dibagiandalamproduksisudahsebagianbesarditerapkansebesar 75%, danbagianhasilproduksibarulebihdarisetengahnyaditerapkansebesar 63%. ;---Good Manufacturing Production are things that are needed in an industry that is carried out in a sample of home industries in the city of Cimahi. The purpose of this study was to obtain information about good production methods in the home industry in Cimahi City on the outside, inside and production. The reason for this research is the results of research conducted by researchers in several home industries in Cimahi City that still have non-existent processing methods, unclean environments, and use tools that are not intended for food processing. The method used in this study is descriptive explanatory method with an explanatory sequential method approach. The explanatory sequential mixed method is a method of collecting quantitative and qualitative data in two phases, with one form of data and providing information on other forms of data. In this study qualitative data will strengthen quantitative data. Findings in the research that have been carried out are still found in indicators that have never been applied by the sample as a cracker house industry in Cimahi City. The application of good food production methods in the outer part of production has been more than half is 63% applied, in most parts of the production has been mostly is 75% applied, and the share of new production is more than half is 63% applied

Redefining southern Australia's climatic regions and seasons

Climate scientists routinely rely on averaging over time or space to simplify complex information and to concisely communicate findings. Currently, no consistent definitions of 'warm' or 'cool' seasons for southern Australia exist, making comparisons across studies difficult. Similarly, numerous climate studies in Australia use either arbitrarily defined areas or the Natural Resource Management (NRM) clusters to perform spatial averaging. While the NRM regions were informed by temperature and rainfall information, they remain somewhat arbitrary. Here we use weather type influence on rainfall and clustering methods to quantitatively define climatic regions and seasons over southern Australia. Three methods are explored: k-means clustering and two agglomerative clustering methods, Ward linkage and average linkage. K-means was found to be preferred in temporal clustering, while the average linkage method was preferred for spatial clustering. For southern Australia as a whole, we define the cool season as April-September and warm season as October-March, though we note that a three-season split may provide more nuanced climate analysis. We also show that different regions across southern Australia experience different seasons and demonstrate the changing spatial influence of weather types with the seasons, which may aid regionally or seasonally specific climate analysis. Division of southern Australia into 15 climatic regions shows localised agreement with the NRM clusters where distinct differences in rainfall amounts exist. However, the climate regions defined here better represent the importance of topographical aspect on weather type influence and the inland extent of particular weather types. We suggest that the use of these regions would provide consistent climate analysis across studies if widely adopted. A key requirement for climate scientists is the simplification of data sets into both seasonally or regionally averaged subsets. This simplification, by grouping like regions or seasons, is done for a number of reasons both scientific and practical, including to help understand patterns of variability, underlying drivers and trends in climate and weather, to communicate large amounts of data concisely, to reduce the amount of data required for processing (which becomes increasingly important with higher resolution climate model output), or to more simply draw a physical boundary between regions for other purposes, such as flora and fauna habitat analysis, appropriate agricultural practices or water management.Statistic