Geometric Network Creation Games

Network Creation Games are a well-known approach for explaining and analyzing the structure, quality and dynamics of real-world networks like the Internet and other infrastructure networks which evolved via the interaction of selfish agents without a central authority. In these games selfish agents which correspond to nodes in a network strategically buy incident edges to improve their centrality. However, past research on these games has only considered the creation of networks with unit-weight edges. In practice, e.g. when constructing a fiber-optic network, the choice of which nodes to connect and also the induced price for a link crucially depends on the distance between the involved nodes and such settings can be modeled via edge-weighted graphs. We incorporate arbitrary edge weights by generalizing the well-known model by Fabrikant et al.[PODC'03] to edge-weighted host graphs and focus on the geometric setting where the weights are induced by the distances in some metric space. In stark contrast to the state-of-the-art for the unit-weight version, where the Price of Anarchy is conjectured to be constant and where resolving this is a major open problem, we prove a tight non-constant bound on the Price of Anarchy for the metric version and a slightly weaker upper bound for the non-metric case. Moreover, we analyze the existence of equilibria, the computational hardness and the game dynamics for several natural metrics. The model we propose can be seen as the game-theoretic analogue of a variant of the classical Network Design Problem. Thus, low-cost equilibria of our game correspond to decentralized and stable approximations of the optimum network design.Comment: Accepted at 31st ACM Symposium on Parallelism in Algorithms and Architectures (SPAA '19). 33 pages, 11 figure

Modified 2D Proca Theory: Revisited Under BRST and (Anti-)Chiral Superfield Formalisms

Within the framework of Becchi-Rouet-Stora-Tyutin (BRST) approach, we discuss mainly the fermionic (i.e. off-shell nilpotent) (anti-)BRST, (anti-)co-BRST and some discrete dual-symmetries of the appropriate Lagrangian densities for a two (1+1)-dimensional (2D) modified Proca (i.e. a massive Abelian 1-form) theory without any interaction with matter fields. One of the novel observations of our present investigation is the existence of some kinds of restrictions in the case of our present St\"{u}ckelberg-modified version of the 2D Proca theory which is not like the standard Curci-Ferrari (CF)-condition of a non-Abelian 1-form gauge theory. Some kinds of similarities and a few differences between them have been pointed out in our present investigation. To establish the sanctity of the above off-shell nilpotent (anti-)BRST and (anti-)co-BRST symmetries, we derive them by using our newly proposed (anti-)chiral superfield formalism where a few specific and appropriate sets of invariant quantities play a decisive role. We express the (anti-)BRST and (anti-)co-BRST conserved charges in terms of the superfields that are obtained after the applications of (anti-)BRST and (anti-)co-BRST invariant restrictions and prove their off-shell nilpotency and absolute anticommutativity properties, too. Finally, we make some comments on (i) the novelty of our restrictions/obstructions, and (ii) the physics behind the negative kinetic term associated with the pseudo-scalar field of our present theory.Comment: LaTeX file, 58 pages, Journal reference give

A Historical Survey of the Economic Development of Mainland China, 1949-1962

Chinese agriculture differs from the Western agriculture in the development and utilization of agricultural science on the fields. China has always been an agricultural country, but she failed to improve in techniques of cultivation as the time passed by. The land, prior to the Communist take-over, was owned and cultivated by individuals and the produce was sold in a free-market. Unfortunately, the Chinese government, prior to 1949, failed to bring about adequate agricultural reforms and implement economic development measures. As a result an overwhelming proportion of the population of China is occupied on the land, the supply of which is fixed, and the capital resources employed are small, the per capita output and income of China are low. With the vast majority of the population in agriculture and low per capita output, the national income of the country is also low. Thus, China is classified as an underdeveloped nation. Arising from the same problem of overpopulation, the family land was subdivided and fragmented into economically inefficient units before the Communist take-over

The Effect of Mg Doping on Structural and Luminescent Properties of Barium Strontium Titanate (BST)

AbstractPure and Mg doped barium strontium titanate (BST) phosphor samples are prepared by solid state reaction (SSR) method at 1300°c. The prepared samples are characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-VIS absorption spectroscopy. The optical properties are studied in terms of mechanoluminescence (ML) and thermoluminescence (TL). The XRD results reveal perovskite structure of samples with XRD peaks corresponding to planes (100), (110), (111), (200) and (211). The SEM micrographs exhibit agglomeration of particles of different shapes. The particle size calculated using SEM and XRD data is found to lie in nano range. The ML intensity is found to depend on applied load while the TL intensity increases with increasing irradiation time

Benefit of irrigation water transfers in the National River Linking Project: a case study of the Ken-Betwa link

River basin managementRiver basin developmentDevelopment projectsWater transferIrrigation waterCrop productionCrop managementLivestock

Thermal convection of viscoelastic fluids in concentric rotating cylinders: Elastic turbulence and kinetic energy budget analysis

The introduction of solid polymers into a Newtonian solvent induces significant modifications in the flow behavior and heat transfer characteristics of resulting viscoelastic fluids. This study performs a comprehensive numerical investigation on thermal convection within a system comprising two concentric horizontal cylinders filled with viscoelastic fluids, with the inner cylinder rotating. The analysis encompasses all three modes of thermal convection, namely, forced, free, and mixed convection, over a range of Weissenberg numbers up to 10 and three values of the Richardson number, namely, 0, 0.143, and $\infty$, representing forced, mixed, and free convection modes of heat transfer, respectively. In forced convection, the flow field remains stable, while in free and mixed convection, an increase in the Weissenberg number leads to a transition from steady to unsteady periodic, quasi-periodic, and finally, an aperiodic and chaotic behavior. This transition arises due to the presence of elastic instability and the subsequent appearance of elastic turbulence in viscoelastic fluids with the increasing Weissenberg number. Furthermore, our findings indicate that fluid viscoelasticity has minimal influence on heat transfer rates in the cases of forced and free convection. Conversely, heat transfer rates in mixed convection increase with the Weissenberg number. We conduct a detailed analysis of the viscoelastic kinetic energy budget to elucidate this enhancement in the heat transfer rate for viscoelastic fluids. We show that this improved heat transfer results from kinetic energy transfer from polymer molecules to the flow field, leading to increased chaotic motion within the system and, eventually, higher heat transfer rates

Acute BVDV infection inhibits expression of interferon-stimulated genes during pregnancy recognition in bovine endometrium

Bovine viral diarrhea virus (BVDV) can evade host detection by downregulation of interferon signaling pathways. Infection of cows with noncytopathic (ncp) BVDV can cause early embryonic mortality. Upregulation of type I interferon stimulated genes (ISGs) by blastocyst-secreted interferon tau (IFNT) is a crucial component of the maternal recognition of pregnancy (MRP) in ruminants. This study investigated the potential of acute BVDV infection to disrupt MRP by modulating endometrial ISG expression. Endometrial cells from 10 BVDV-free cows were cultured and treated with 0 or 100 ng/ml IFNT for 24 h in the absence or presence of ncpBVDV infection to yield four treatment groups: CONT, ncpBVDV, IFNT, or ncpBVDV+IFNT. ncpBVDV infection alone only upregulated TRIM56, but reduced mRNA expression of ISG15, MX2, BST2, and the proinflammatory cytokine IL1B. As anticipated, IFNT treatment alone significantly increased expression of all 17 ISGs tested. In contrast to the limited effect of ncpBVDV alone, the virus markedly inhibited IFNT-stimulated expression of 15 ISGs tested (ISG15, HERC5, USP18, DDX58, IFIH1, IFIT1, IFIT3, BST2, MX1, MX2, RSAD2, OAS1Y, SAMD9, GBP4, and PLAC8), together with ISG15 secreted protein. Only TRIM56 and IFI27 expression was unaltered. IL1B expression was reduced by the combined treatment. These results indicate that acute ncpBVDV infection may decrease uterine immunity and lead to MRP failure through inhibition of IFNT-stimulated endometrial ISG production. This in turn could reduce fertility and predispose cows to uterine disease, while evasion of the normal uterine immune response by ncpBVDV may contribute to maintenance and spreading of this economically important disease