Dynamical reduction of the dimensionality of exchange interactions and the "spin-liquid" phase of κ\kappa-(BEDT-TTF)2X_2X

We show that the anisotropy of the effective spin model for the dimer Mott insulator phase of $\kappa$-(BEDT-TTF)$_2X$ salts is dramatically different from that of the underlying tight-binding model. Intra-dimer quantum interference results in a model of coupled spin chains, where frustrated interchain interactions suppress long-range magnetic order. Thus, we argue, the "spin liquid" phase observed in some of these materials is a remnant of the Tomonaga-Luttinger physics of a single chain. This is consistent with previous experiments and resolves some outstanding puzzles. An erratum [Phys. Rev. Lett. 120, 199901 (2018).] is added as an appendix.Comment: Accepted by PRL, 6 pages, 5 figure

Towards mechanomagnetics in elastic crystals: insights from [Cu(acac)2_2]

We predict that the magnetic properties of \cuacac, an elastically flexible crystal, change dramatically when the crystal is bent. We find that unbent \cuacac\ is an almost perfect Tomonaga-Luttinger liquid. Broken-symmetry density functional calculations reveal that the magnetic exchange interactions along the chains is an order of magnitude larger than the interchain exchange. The geometrically frustrated interchain interactions cannot magnetically order the material at any experimentally accessible temperature. The ordering temperature ($T_N$), calculated from the chain random phase approximation, increases by approximately 24 orders of magnitude when the material is bent. We demonstrate that geometric frustration both suppresses $T_N$ and enhances the sensitivity of $T_N$ to bending. In \cuacac, $T_N$ is extremely sensitive to bending, but remains too low for practical applications, even when bent. Partially frustrated materials could achieve the balance of high $T_N$ and good sensitivity to bending required for practical applications of mechanomagnetic elastic crystals

Code or Contract: Whether Wal-Mart\u27s Code of Conduct Creates a Contractual Obligation Between Wal-Mart and the Employees of its Foreign Suppliers

This comment examines whether corporate codes of conduct and more specifically, Wal-Mart\u27s Code of Conduct, are binding contracts between foreign suppliers and their employees or whether they are voluntary and non-contractual devices. An analysis of U.S. law and the text and implementation of Wal-Mart\u27s Code of Conduct reveals that the Code should not be interpreted as a contract binding on foreign suppliers and their employees for the breach of contract for denial of minimum and overtime wages, the breach of contract for forced labor, and the breach of contract for denial of the fundamental right to freely associate. The comment goes on to discuss the ramifications of this type of suit and other possibilities for bringing about the successful reform of labor conditions for foreign workers. This comment concludes that the best means for reform is not litigation but legislation. Part II of this comment discusses the historical origins of corporate codes of conduct and the role that they currently play within MNCs. Part III discusses how courts in the United States have interpreted corporate codes of conduct. Part IV analyzes the text and implementation of Wal-Mart\u27s Code of Conduct and determines whether it should be interpreted as a contract or mere guidelines in light of recent court rulings. Part V analyzes the impact of the lawsuit and discusses the appropriateness of other possible means for reforming foreign working conditions. Part VI draws conclusions with respect to the most effective means of impacting workers\u27 conditions, such as grassroot efforts

Automated tutoring for a database skills training environment

Universities are increasingly offering courses online. Feedback, assessment, and guidance are important features of this online courseware. Together, in the absence of a human tutor, they aid the student in the learning process. We present a programming training environment for a database course. It aims to offer a substitute for classroom based learning by providing synchronous automated feedback to the student, along with guidance based on a personalized assessment. The automated tutoring system should promote procedural knowledge acquisition and skills training. An automated tutoring feature is an integral part of this tutoring system

Certified Weed Free Hay and Straw Program

There is a growing demand in North America for the use of certified weed free hay and straw as a preventative program to limit the spread of noxious weeds. This voluntary certification program is designed to assure that hay and straw sold with proper certification identification meets minimum standards designed to limit the spread of noxious and undesirable weeds. Buyers are provided assurance that hay and straw certified through this program meets these minimum standards

Code or Contract: Whether Wal-Mart\u27s Code of Conduct Creates a Contractual Obligation Between Wal-Mart and the Employees of its Foreign Suppliers

This comment examines whether corporate codes of conduct and more specifically, Wal-Mart\u27s Code of Conduct, are binding contracts between foreign suppliers and their employees or whether they are voluntary and non-contractual devices. An analysis of U.S. law and the text and implementation of Wal-Mart\u27s Code of Conduct reveals that the Code should not be interpreted as a contract binding on foreign suppliers and their employees for the breach of contract for denial of minimum and overtime wages, the breach of contract for forced labor, and the breach of contract for denial of the fundamental right to freely associate. The comment goes on to discuss the ramifications of this type of suit and other possibilities for bringing about the successful reform of labor conditions for foreign workers. This comment concludes that the best means for reform is not litigation but legislation. Part II of this comment discusses the historical origins of corporate codes of conduct and the role that they currently play within MNCs. Part III discusses how courts in the United States have interpreted corporate codes of conduct. Part IV analyzes the text and implementation of Wal-Mart\u27s Code of Conduct and determines whether it should be interpreted as a contract or mere guidelines in light of recent court rulings. Part V analyzes the impact of the lawsuit and discusses the appropriateness of other possible means for reforming foreign working conditions. Part VI draws conclusions with respect to the most effective means of impacting workers\u27 conditions, such as grassroot efforts