Effective potential for composite operators and for an auxiliary scalar field in a Nambu-Jona-Lasinio model

We derive the effective potentials for composite operators in a Nambu-Jona-Lasinio (NJL) model at zero and finite temperature and show that in each case they are equivalent to the corresponding effective potentials based on an auxiliary scalar field. The both effective potentials could lead to the same possible spontaneous breaking and restoration of symmetries including chiral symmetry if the momentum cutoff in the loop integrals is large enough, and can be transformed to each other when the Schwinger-Dyson (SD) equation of the dynamical fermion mass from the fermion-antifermion vacuum (or thermal) condensates is used. The results also generally indicate that two effective potentials with the same single order parameter but rather different mathematical expressions can still be considered physically equivalent if the SD equation corresponding to the extreme value conditions of the two potentials have the same form.Comment: 7 pages, no figur

Reflections on the History of the Indian Ocean: the sources and their relation to local practices and global connectivities

This paper discusses the interpretation of sources for Indian Ocean history, from the point of view of translocal interpretations beyond the locality of the source. The article presents three cases, all deriving from the Muslim South-Western Indian Ocean. The argument is made that the ambiguity of the sources, and the interrelationship between the various locations related to the source, affect not only the historians interpretation but also the sense of the past held by people in these locations

Nuclear spin-lattice relaxation rate in the D+iD superconducting state: implications for CoO superconductor

We calculated the nuclear spin-lattice relaxation rate $1/T_1$ for the D+iD superconducting state with impurities. We found that small amount of unitary impurities quickly produces the residual density of states inside the gap. As a result, the T-linear behavior in 1/T$_1$ is observed at low temperatures. Our results show that the D+iD pairing symmetry of the superconducting state of Na$_{0.35}$CoO$_{2} \cdot y$H$_2$ O is compatible with recent $^{59}$Co 1/T$_1$ experiments of several groups.Comment: 5 pages, 4 figures, minor change

Collapse arrest and soliton stabilization in nonlocal nonlinear media

We investigate the properties of localized waves in systems governed by nonlocal nonlinear Schrodinger type equations. We prove rigorously by bounding the Hamiltonian that nonlocality of the nonlinearity prevents collapse in, e.g., Bose-Einstein condensates and optical Kerr media in all physical dimensions. The nonlocal nonlinear response must be symmetric, but can be of completely arbitrary shape. We use variational techniques to find the soliton solutions and illustrate the stabilizing effect of nonlocality.Comment: 4 pages with 3 figure

Direct imaging of long-range ferromagnetic and antiferromagnetic order in a dipolar metamaterial

Magnetic metamaterials such as artificial spin ice offer a route to tailor magnetic properties. Such materials can be fabricated by lithographically defining arrays of nanoscale magnetic islands. The magnetostatic interactions between the elements are influenced by their shape and geometric arrangement and can lead to long-range ordering. We demonstrate how the magnetic order in a two-dimensional periodic array of circular disks is controlled by the lattice symmetry. Antiferromagnetic and ferromagnetic order extending through the entire array is observed for the square and hexagonal lattice, respectively. Furthermore, we show that a minute deviation from perfect circularity of the elements along a preferred direction results in room-temperature blocking and favors collinear spin textures

Burn septicaemia in Kuwait: associated demographic and clinical factors

Objective: To study the demographic and clinical factors associated with burn septicaemia patients in Kuwait. Materials and Methods: All burn in-patients, who developed septicaemia at the Burns Unit, Al-Babtain Centre for Burns and Plastic Surgery, Kuwait, during a 9-year period (June 1992 to May 2001) were included in the study. The data were recorded for age, sex, nationality, cause and percentage of burns, inhalation injury, resuscitation, number of episodes, septicaemia on post-burn day, the microorganisms responsible in each episode, treatment and outcome for statistical analysis. Using SPSS (PC version 11.0) software, a probability level of p<0.05 was considered significant. Results: Of the 2,082 patients treated in the Burns Unit, 166 [8%; 99 (60%) males and 67 (40%) females] with a mean age of 26 years (range 1-70) had septicaemia. Significantly higher (p <0.001) cases were recorded among Kuwaiti children (≤14 years) and non-Kuwaitis (25-59 years) than other corresponding age groups. The total body surface area burned ranged from 2 to 95% (mean 42%) and the main cause of burn was flame (77.1%). Inhalation injury was diagnosed in 39 (23.5%) patients. A total of 253 septicaemic episodes occurred in all patients. The majority, 123 (74.1%), had a single episode and the remaining 43 (25.6%) had multiple (2-10) episodes. One hundred and fifty-five (61.3%) episodes were due to gram-positive organisms, mainly methicillin-resistant Staphylococcus aureus, and 32 (12.7%) were polymicrobial. One hundred and twenty-four (74.7%) patients had wound excision and skin grafting procedures and their survival was significantly higher (OR=4.3; 95% CI: 1.98-9.31) than nonsurgically treated patients. Thirty-nine (23.5%) patients died mainly due to multi-organ failure. Conclusion: The findings indicate that the patients with extensive flame burns were prone to developing septicaemia due mainly to gram-positive bacteria. The surgical excision of eschar and wound covering improved the outcome of the patients while prophylactic antibiotic treatment had no role in the incidence and outcome of the burn patients

Compact contenders? Investigating cost competitiveness requirements of small modular nuclear reactors and their potential impact on the European energy system

Europe is currently in the process of executing a strategy to increase the share of renewable energy in its electricity mix. However, concerns about energy system instability, higher transmission costs, and energy security have sparked discussions about the potential integration of alternative technologies, such as small modular nuclear reactors (SMR), which offer stable output and high flexibility. In view of the ongoing debate and the uncertainty surrounding the cost estimations of SMR, this study first attempts to establish a reference range for SMR that would ensure its economic viability for inclusion in the energy system. We then perform a comparison of European energy systems, with and without SMR, to explore how the inclu sion of SMR can impact the energy system. Lastly, we delve into learning effects to assess the potential for increased competitiveness in the future. Our results show that if the construction cost of SMR remains below 7392 euros/kw and operational cost does not exceed 230 euros/kw, SMR could become competitive and reduce overall energy system costs. This potential cost reduction arises from SMR’s ability to replace traditional large-scale nuclear power plants, which have high upfront and operating expenses, and to compete with variable renewable energy sources by lowering transmission cost. Furthermore, learning effects could enhance the competitiveness of SMR in the future, even if they currently lack a cost-related advantage