Exploring the magnetic properties of the largest single molecule magnets

The giant {Mn₇₀} and {Mn₈₄} wheels are the largest nuclearity single-molecule magnets synthesized to date, and understanding their magnetic properties poses a challenge to theory. Starting from first-principles calculations, we explore the magnetic properties and excitations in these wheels using effective spin Hamiltonians. We find that the unusual geometry of the superexchange pathways leads to weakly coupled {Mn₇} subunits carrying an effective S = 2 spin. The spectrum exhibits a hierarchy of energy scales and massive degeneracies, with the lowest-energy excitations arising from Heisenberg-ring-like excitations of the {Mn₇} subunits around the wheel. We further describe how weak longer-range couplings can select the precise spin ground-state of the Mn wheels out of the nearly degenerate ground-state band

How is Death Penalty Used in China?

Strike hard Campaigns. The Views of the People and of the Elite. Comments on the interplay between penal populism, leadership from the front and human rights. To what extent are hard strike campaigns formed as penal populism in the provinces or as a result of leadership from the front centrally. The hard strike campaigns in the future. (Preliminary Symposium Program for The first Oslo international Symposium on Death penalty in Asia)published_or_final_versio

Chapter 7 Review: Effects of Microplastic on Zooplankton Survival and Sublethal Responses

Microplastics (MPs) are a prolific contaminant in aquatic ecosystems across the globe. Zooplankton (including holoplankton and meroplankton) play vital ecological roles in marine and freshwater ecosystems and have been shown to readily consume MPs. The present review uses 88 pieces of published literature to examine and compare the effects of MPs on survival, growth, development, feeding rate, swimming speed, reproduction, organ damage and gene expression of different groups of zooplankton including copepods, daphnids, brine shrimp, euphausids, rotifers and the larvae of fishes, sea urchins, molluscs, barnacles, decapods and ascidians. Among the groups studied, daphnids and copepods are the most sensitive to MPs, with their feeding rate and fecundity significantly decreased at environmentally relevant MP concentrations. This might adversely affect daphnids and copepods populations in the long term. In contrast, molluscs, barnacles, brine shrimp and euphausids appear to be more tolerant to MPs. No clear impacts on survival, development time, growth or feeding rate can be observed in these zooplankton groups at any of the MP concentrations tested, suggesting that these groups might become more dominant with prolonged exposure to MP pollution. Leachates derived from MPs can induce severe abnormality in bivalve and sea urchin embryos. MPs have prominent effects on survival and fecundity of F1 offspring in bivalves, copepods and daphnids, indicating that MPs could incite transgenerational effects and drastically affect sustainability in zooplankton populations

A "data sharing trust" model for rapid, collaborative science

Complex datasets provide opportunities for discoveries beyond their initial scope. Effective and rapid data sharing andmanagement practices are crucial to realize this potential; however, they are harder to implement than post-publication access. Here, we introduce the concept of a "data sharing trust'' tomaximize the value of large datasets

The failure of stellar feedback, magnetic fields, conduction, and morphological quenching in maintaining red galaxies

The quenching "maintenance'" and related "cooling flow" problems are important in galaxies from Milky Way mass through clusters. We investigate this in halos with masses $\sim 10^{12}-10^{14}\,{\rm M}_{\odot}$, using non-cosmological high-resolution hydrodynamic simulations with the FIRE-2 (Feedback In Realistic Environments) stellar feedback model. We specifically focus on physics present without AGN, and show that various proposed "non-AGN" solution mechanisms in the literature, including Type Ia supernovae, shocked AGB winds, other forms of stellar feedback (e.g. cosmic rays), magnetic fields, Spitzer-Braginskii conduction, or "morphological quenching" do not halt or substantially reduce cooling flows nor maintain "quenched" galaxies in this mass range. We show that stellar feedback (including cosmic rays from SNe) alters the balance of cold/warm gas and the rate at which the cooled gas within the galaxy turns into stars, but not the net baryonic inflow. If anything, outflowing metals and dense gas promote additional cooling. Conduction is important only in the most massive halos, as expected, but even at $\sim 10^{14}\,{\rm M}_{\odot}$ reduces inflow only by a factor $\sim 2$ (owing to saturation effects and anisotropic suppression). Changing the morphology of the galaxies only slightly alters their Toomre-$Q$ parameter, and has no effect on cooling (as expected), so has essentially no effect on cooling flows or maintaining quenching. This all supports the idea that additional physics, e.g., AGN feedback, must be important in massive galaxies.Comment: 16 pages, 12 figure

SPRING: speech and pronunciation improvement through games, for Hispanic children

Lack of proper English pronunciations is a major problem for immigrant population in developed countries like U.S. This poses various problems, including a barrier to entry into mainstream society. This paper presents a research study that explores the use of speech technologies merged with activity-based and arcade-based games to do pronunciation feedback for Hispanic children within the U.S. A 3-month long study with immigrant population in California was used to investigate and analyze the effectiveness of computer aided pronunciation feedback through games. In addition to quantitative findings that point to statistically significant gains in pronunciation quality, the paper also explores qualitative findings, interaction patterns and challenges faced by the researchers in dealing with this community. It also describes the issues involved in dealing with pronunciation as a competency.Comment: ACM ICTD 201

Exploring the magnetic properties of the largest single molecule magnets

The giant {Mn₇₀} and {Mn₈₄} wheels are the largest nuclearity single-molecule magnets synthesized to date, and understanding their magnetic properties poses a challenge to theory. Starting from first-principles calculations, we explore the magnetic properties and excitations in these wheels using effective spin Hamiltonians. We find that the unusual geometry of the superexchange pathways leads to weakly coupled {Mn₇} subunits carrying an effective S = 2 spin. The spectrum exhibits a hierarchy of energy scales and massive degeneracies, with the lowest-energy excitations arising from Heisenberg-ring-like excitations of the {Mn₇} subunits around the wheel. We further describe how weak longer-range couplings can select the precise spin ground-state of the Mn wheels out of the nearly degenerate ground-state band