From first-order magneto-elastic to magneto-structural transition in (Mn,Fe)1.95P0.50Si0.50 compounds

We report on structural, magnetic and magnetocaloric properties of MnxFe1.95-xP0.50Si0.50 (x > 1.10) compounds. With increasing the Mn:Fe ratio, a first-order magneto-elastic transition gradually changes into a first-order magneto-structural transition via a second-order magnetic transition. The study also shows that thermal hysteresis can be tuned by varying the Mn:Fe ratio. Small thermal hysteresis (less than 1 K) can be obtained while maintaining a giant magnetocaloric effect. This achievement paves the way for real refrigeration applications using magnetic refrigerants.Comment: 4 pages, 3 figures, Supplemental Materia

Autoethnography as a Decolonizing Methodology: Reflections on Masta’s What the Grandfathers Taught Me

As an Asian graduate student and a Native professor at a U.S. Midwestern Predominantly White Institution, we reflected upon Masta’s (2018) article, What the Grandfathers Taught Me: Lessons for an Indian Country Researcher, to examine the decolonizing aspects of autoethnography. Masta’s use of autoethnography to explore her experiences provides a deeply personal view into the phenomenon of living and researching Indigenous in an America that is inherently White in character, tradition, structure, and culture. The use of participatory and constructivist Indigenous autoethnography places the lived experience of an Indigenous woman at the center of the study, using the Indigenous lens to respect the cultural values, beliefs, and teachings of a community that remains largely overlooked in Eurocentric research. Such an appreciation and understanding led us to argue that autoethnography is a promising decolonizing methodology which has the potential to inform decolonization and social justice movements

Assessment of the Impacts of Health Related Millennium Development Goals’ Intervention on Economic Growth in Nigeria: 2000-2015

In September, 2000, the 189 member states of the United Nations unanimously adopted a millennium declaration tagged “The Millennium Development Goals (MDGs).” as an attempt to address the challenges relating to extreme poverty, hunger, health, gender equality, education, environmental sustainability and global partnership for development. Three of the goals were health-specific while the others can be regarded as health enhancing as there exist some form of positive correlation between health system development and sustainable economic growth. This study empirically investigates the effect of Millennium Development Goals’ (MDGs) health interventions on economic growth in Nigeria for the period 2000 – 2015. It adopts the least squares regression analysis to examine the impact of MDGs 4, 5, and 6 in improving the health system performance for Nigeria’s economic growth. The model adopted views health as a durable capital stock that yields an output of a healthy economy whose production function account for the gap between health care as an output and medical care as an input into the aggregate output of an economy. Results show that increased recurrent expenditures on health and reduction in infant mortality rate has positive impact on economic growth while low life expectancy at birth, high rate of maternal mortality rate and the spread of HIV/AIDS have negative impact on economic growth/. The study conclude with recommendations including increase in public spending on health, targeting intervention on high risk and vulnerable women and children, as well as  speeding up efforts to track down the spread of HIV/AIDs among others as means to achieve sustainable growth

Challenges in Bridging Social Semantics and Formal Semantics on the Web

This paper describes several results of Wimmics, a research lab which names stands for: web-instrumented man-machine interactions, communities, and semantics. The approaches introduced here rely on graph-oriented knowledge representation, reasoning and operationalization to model and support actors, actions and interactions in web-based epistemic communities. The re-search results are applied to support and foster interactions in online communities and manage their resources

Spectral Theory for Non-linear Superconducting Microwave Systems: Extracting Relaxation Rates and Mode Hybridization

The accurate modeling of mode hybridization and calculation of radiative relaxation rates have been crucial to the design and optimization of superconducting quantum devices. In this work, we introduce a spectral theory for the electrohydrodynamics of superconductors that enables the extraction of the relaxation rates of excitations in a general three-dimensional distribution of superconducting bodies. Our approach addresses the long-standing problem of formulating a modal description of open systems that is both efficient and allows for second quantization of the radiative hybridized fields. This is achieved through the implementation of finite but transparent boundaries through which radiation can propagate into and out of the computational domain. The resulting spectral problem is defined within a coarse-grained formulation of the electrohydrodynamical equations that is suitable for the analysis of the non-equilibrium dynamics of multiscale superconducting quantum systems.Comment: 21 pages, 12 figures, journal pape

Topological insulators and topological non-linear sigma models

In this paper we link the physics of topological nonlinear {\sigma} models with that of Chern-Simons insulators. We show that corresponding to every 2n-dimensional Chern-Simons insulator there is a (n-1)-dimensional topological nonlinear {\sigma} model with the Wess-Zumino-Witten term. Breaking internal symmetry in these nonlinear {\sigma} models leads to nonlinear {\sigma} models with the {\theta} term. [This is analogous to the dimension reduction leading from 2n-dimensional Chern-Simons insulators to (2n-1) and (2n-2)-dimensional topological insulators protected by discrete symmetries.] The correspondence described in this paper allows one to derive the topological term in a theory involving fermions and order parameters (we shall referred to them as "fermion-{\sigma} models") when the conventional gradient-expansion method fails. We also discuss the quantum number of solitons in topological nonlinear {\sigma} model and the electromagnetic action of the (2n-1)-dimensional topological insulators. Throughout the paper we use a simple model to illustrate how things work.Comment: 18 pages, 11 figures (figure problem fixed

Characterizing rings in terms of the extent of injectivity and projectivity of their modules

Given a ring R, we define its right i-profile (resp. right p-profile) to be the collection of injectivity domains (resp. projectivity domains) of its right R-modules. We study the lattice theoretic properties of these profiles and consider ways in which properties of the profiles may determine the structure of rings and viceversa. We show that the i-profile is isomorphic to an interval of the lattice of linear filters of right ideals of R, and is therefore modular and coatomic. In particular, we give a practical characterization of the i-profile of a right artinian ring. We show through an example that the p-profile is not necessarily a set, and also characterize the right p-profile of a right perfect ring. The study of rings in terms of their (i- or p-)profile was inspired by the study of rings with no (i- or p-) middle class, initiated in recent papers by Er, L\'opez-Permouth and S\"okmez, and by Holston, L\'opez-Permouth and Orhan-Ertas. In this paper, we obtain further results about these rings and we also use our results to provide a characterization of a special class of QF-rings in which the injectivity and projectivity domains of any module coincide.Comment: 19 pages, examples and propositions added. Title change

Magnetic order tuned by Cu substitution in Fe1.1-zCuzTe

We study the effects of Cu substitution in Fe1.1Te, the non-superconducting parent compound of the iron-based superconductor, Fe1+yTe1-xSex, utilizing neutron scattering techniques. It is found that the structural and magnetic transitions, which occur at \sim 60 K without Cu, are monotonically depressed with increasing Cu content. By 10% Cu for Fe, the structural transition is hardly detectable, and the system becomes a spin glass below 22 K, with a slightly incommensurate ordering wave vector of (0.5-d, 0, 0.5) with d being the incommensurability of 0.02, and correlation length of 12 angstrom along the a axis and 9 angstrom along the c axis. With 4% Cu, both transition temperatures are at 41 K, though short-range incommensurate order at (0.42, 0, 0.5) is present at 60 K. With further cooling, the incommensurability decreases linearly with temperature down to 37 K, below which there is a first order transition to a long-range almost-commensurate antiferromagnetic structure. A spin anisotropy gap of 4.5 meV is also observed in this compound. Our results show that the weakly magnetic Cu has large effects on the magnetic correlations; it is suggested that this is caused by the frustration of the exchange interactions between the coupled Fe spins.Comment: 7 pages, 7 figures, version as appeared on PR

Modeling Stable Matching Problems with Answer Set Programming

The Stable Marriage Problem (SMP) is a well-known matching problem first introduced and solved by Gale and Shapley (1962). Several variants and extensions to this problem have since been investigated to cover a wider set of applications. Each time a new variant is considered, however, a new algorithm needs to be developed and implemented. As an alternative, in this paper we propose an encoding of the SMP using Answer Set Programming (ASP). Our encoding can easily be extended and adapted to the needs of specific applications. As an illustration we show how stable matchings can be found when individuals may designate unacceptable partners and ties between preferences are allowed. Subsequently, we show how our ASP based encoding naturally allows us to select specific stable matchings which are optimal according to a given criterion. Each time, we can rely on generic and efficient off-the-shelf answer set solvers to find (optimal) stable matchings.Comment: 26 page