2,201 research outputs found

    Can Neuroscience Help Predict Future Antisocial Behavior?

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    Part I of this Article reviews the tools currently available to predict antisocial behavior. Part II discusses legal precedent regarding the use of, and challenges to, various prediction methods. Part III introduces recent neuroscience work in this area and reviews two studies that have successfully used neuroimaging techniques to predict recidivism. Part IV discusses some criticisms that are commonly levied against the various prediction methods and highlights the disparity between the attitudes of the scientific and legal communities toward risk assessment generally and neuroscience specifically. Lastly, Part V explains why neuroscience methods will likely continue to help inform and, ideally, improve the tools we use to help assess, understand, and predict human behavior

    Interplay of Magnetism and Transport in HoBi

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    We report the observation of an extreme magnetoresistance (XMR) in HoBi with a large magnetic moment from Ho f-electrons. Neutron scattering is used to determine the magnetic wave vectors across several metamagnetic (MM) transitions on the phase diagram of HoBi. Unlike other magnetic rare-earth monopnictides, the field dependence of resistivity in HoBi is non-monotonic and reveals clear signatures of every metamagnetic transition in the low-temperature and low-field regime, at T < 2 K and H < 2.3 T. The XMR appears at H > 2.3 T after all the metamagnetic transitions are complete and the system is spin-polarized by the external magnetic field. The existence of an onset field for XMR and the intimate connection between magnetism and transport in HoBi are unprecedented among the magnetic rare-earth monopnictides. Therefore, HoBi provides a unique opportunity to understand the electrical transport in magnetic XMR semimetals.Comment: 6 pages, 4 figure

    Gapped and gapless short range ordered magnetic states with (12,12,12)(\frac{1}{2},\frac{1}{2},\frac{1}{2}) wavevectors in the pyrochlore magnet Tb2+x_{2+x}Ti2x_{2-x}O7+δ_{7+\delta}

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    Recent low temperature heat capacity (CP_P) measurements on polycrystalline samples of the pyrochlore antiferromagnet Tb2+x_{2+x}Ti2x_{2-x}O7+δ_{7+\delta} have shown a strong sensitivity to the precise Tb concentration xx, with a large anomaly exhibited for x0.005x \sim 0.005 at TC0.5T_C \sim 0.5 K and no such anomaly and corresponding phase transition for x0x \le 0. We have grown single crystal samples of Tb2+x_{2+x}Ti2x_{2-x}O7+δ_{7+\delta}, with approximate composition x=0.001,+0.0042x=-0.001, +0.0042, and +0.0147+0.0147, where the x=0.0042x=0.0042 single crystal exhibits a large CP_P anomaly at TCT_C=0.45 K, but neither the x=0.001x=-0.001 nor the x=+0.0147x=+0.0147 single crystals display any such anomaly. We present new time-of-flight neutron scattering measurements on the x=0.001x=-0.001 and the x=+0.0147x=+0.0147 samples which show strong (12,12,12)\left(\frac{1}{2},\frac{1}{2},\frac{1}{2}\right) quasi-Bragg peaks at low temperatures characteristic of short range antiferromagnetic spin ice (AFSI) order at zero magnetic field but only under field-cooled conditions, as was previously observed in our x=0.0042x = 0.0042 single crystal. These results show that the strong (12,12,12)\left(\frac{1}{2},\frac{1}{2},\frac{1}{2}\right) quasi-Bragg peaks and gapped AFSI state at low temperatures under field cooled conditions are robust features of Tb2_2Ti2_2O7_7, and are not correlated with the presence or absence of the CP_P anomaly and phase transition at low temperatures. Further, these results show that the ordered state giving rise to the CP_P anomaly is confined to 0x0.010 \leq x \leq 0.01 for Tb2+x_{2+x}Ti2x_{2-x}O7+δ_{7+\delta}, and is not obviously connected with conventional order of magnetic dipole degrees of freedom.Comment: 7 pages, 3 figure

    International Governance of Autonomous Military Robots

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    New technologies have always been a critical component of military strategy and preparedness. One new technology on the not-too-distant technological horizon is lethal autonomous robotics, which would consist of robotic weapons capable of exerting lethal force without human control or intervention. There are a number of operational and tactical factors that create incentives for the development of such lethal systems as the next step in the current development, deployment and use of autonomous systems in military forces. Yet, such robotic systems would raise a number of potential operational, policy, ethical and legal issues. This article summarizes the current status and incentives for the development of lethal autonomous robots, discusses some of the issues that would be raised by such systems, and calls for a national and international dialogue on appropriate governance of such systems before they are deployed. The article reviews potential modes of governance, ranging from ethical principles implemented through modifications or refinements of national policies, to changes in the law of war and rules of engagement, to international treaties or agreements, or to a variety of other "soft law" governance mechanisms
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