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

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

Conjugatable water-soluble Pt(ii) and Pd(ii) porphyrin complexes: Novel nano- and molecular probes for optical oxygen tension measurement in tissue engineering

Measurement of oxygen tension in compressed collagen sheets was performed using matrix-embedded optical oxygen sensors based on platinum(II) and palladium(II) porphyrins supported on polyacrylamide nanoparticles. Bespoke, fully water-soluble, mono-functionalised Pt(II) and Pd(II) porphyrin complexes designed for conjugation under mild conditions were obtained using microwave-assisted metallation. The new sensors display a linear response (1/τ vs. O₂) to varying oxygen tension over a biologically relevant range (7.0 × 10⁻⁴ to 2.7 × 10⁻¹ mM) in aqueous solutions; a behaviour that is maintained following conjugation to polyacrylamide nanoparticles, and following embedding of the nanosensors in compressed collagen sheets, paving the way to innovative approaches for real-time resolution of oxygen gradients throughout 3D matrices useful for tissue regeneration

Single grain (LRE)-Ba-Cu-O superconductors fabricated by top seeded melt growth in air

We have recently reported a practical processing method for the fabrication in air of large, single grain (LRE)-Ba-Cu-O [where LRE Nd, Sm, Eu and Gd] bulk superconductors that exhibit high Tc and high Jc. The process is based initially on the development of a new type of generic seed crystal that can promote effectively the epitaxial nucleation of any (RE)-Ba-Cu-O system and, secondly, by suppressing the formation of (LRE)/Ba solid solution in a controlled manner within large LRE-Ba-Cu-O grains processed in air. In this paper we investigate the degree of homogeneity of large grain Sm-Ba-Cu-O superconductors fabricated by this novel process. The technique offers a significant degree of freedom in terms of processing parameters and reproducibility in the growth of oriented single grains in air and yields bulk samples with significantly improved superconducting and field-trapping properties compared to those processed by conventional top seeded melt growth (TSMG)

Element-resolved orbital polarization in (III,Mn)As ferromagnetic semiconductors from KK edge x-ray magnetic circular dichroism

Using x-ray magnetic circular dichroism (XMCD), we determine the element-specific character and polarization of unoccupied states near the Fermi level in (Ga,Mn)As and (In,Ga,Mn)As thin films. The XMCD at the As K absorption edge consists of a single peak located on the low-energy side of the edge, which increases with the concentration of ferromagnetic Mn moments. The XMCD at the Mn K edge is more detailed and is strongly concentration-dependent, which is interpreted as a signature of hole localization for low Mn doping. The results indicate a markedly different character of the polarized holes in low-doped insulating and high-doped metallic films, with a transfer of the hole orbital magnetic moment from Mn to As sites on crossing the metal-insulator transition.Comment: 5 figures, to be published in Physical Review

Young stellar population and ongoing star formation in the HII complex Sh2-252

In this paper an extensive survey of the star forming complex Sh2-252 has been undertaken with an aim to explore its hidden young stellar population as well as to understand the structure and star formation history. This complex is composed of five embedded clusters associated with the sub-regions A, C, E, NGC 2175s and Teu 136. Using 2MASS-NIR and Spitzer-IRAC, MIPS photometry we identified 577 young stellar objects (YSOs), of which, 163 are Class I, 400 are Class II and 14 are transition disk YSOs. Spatial distribution of the candidate YSOs shows that they are mostly clustered around the sub-regions in the western half of the complex, suggesting enhanced star formation activity towards its west. Using the spectral energy distribution and optical colour-magnitude diagram based age analyses, we derived probable evolutionary status of the sub-regions of Sh2-252. Our analysis shows that the region A is the youngest (~ 0.5 Myr), the regions B, C and E are of similar evolutionary stage (~ 1-2 Myr) and the clusters NGC 2175s and Teu 136 are slightly evolved (~ 2-3 Myr). Morphology of the region in the 1.1 mm map shows a semi-circular shaped molecular shell composed of several clumps and YSOs bordering the western ionization front of Sh2-252. Our analyses suggest that next generation star formation is currently under way along this border and that possibly fragmentation of the matter collected during the expansion of the HII region as one of the major processes responsible for such stars. We observed the densest concentration of YSOs (mostly Class I, ~ 0.5 Myr) at the western outskirts of the complex, within a molecular clump associated with water and methanol masers and we suggest that it is indeed a site of cluster formation at a very early evolutionary stage, sandwiched between the two relatively evolved CHII regions A and B.Comment: 19 pages, 13 figures, Accepted for publication in MNRA

Secured Decentralized Confidential Data Distributed in the Disruption-Tolerant Military Network

Disruption tolerant network technologies are becoming successful solutions that allow wireless devices carried by soldiers to communicate with each other and access the confidential information or command reliably by exploiting external storage nodes. Some of the most challenging issues in this scenario are the enforcement of authorization policies and the policies update for secure data retrieval. Cipher text-policy attribute-based encryption is a promising cryptographic solution to the access control issues. However, the problem of applying CP-ABE in decentralized DTNs introduces several security and privacy challenges with regard to the attribute revocation, key escrow, and coordination of attributes issued from different authorities. We propose a secure data retrieval scheme using idea for decentralized DTNs where multiple key authorities manage their attributes independently. We demonstrate how to apply the proposed mechanism to securely and efficiently manage the confidential data distributed in the disruption-tolerant military network

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