Nature of the low temperature ordering of Pr in PrBa_2Cu_3O_(6+x)

Theoretical model is presented to describe the anomalous ordered phase of Pr ions in PrBa_2Cu_3O_(6+x) below T_Pr = 12-17 K. The model considers the Pr multipole degrees of freedom and coupling between the Cu and Pr subsystems. We identify the symmetry allowed coupling of Cu and Pr ions and conclude that only an ab-plane Pr dipole ordering can explain the Cu spin rotation observed at T_Pr by neutron diffraction by Boothroyd et al. [A. T. Boothroyd et al., Phys. Rev. Lett. 78, 130 (1997)]. A substantial enhancement of the Pr ordering temperature is shown to arise from the Cu-Pr coupling which is the key for the anomalous magnetic behavior in PrBa_2Cu_3O_(6+x).Comment: 6 pages, 4 figure

Beta-decay properties of neutron-rich Ca, Ti, and Cr isotopes

Beta-decay properties of neutron-rich Ca, Ti, and Cr isotopes are studied within a deformed proton-neutron quasiparticle random-phase approximation. The underlying mean field is described self-consistently from deformed Skyrme Hartree-Fock calculations with pairing correlations. Residual spin-isospin interactions in the particle-hole and particle-particle channels are also included in the formalism. The energy distributions of the Gamow-Teller strength, the beta-decay feedings, the beta-decay half-lives, and the beta-delayed neutron emission probabilities are discussed and compared with other theoretical results, as well as with the available experimental information. The evolution of these nuclear beta-decay properties is investigated in isotopic chains in a search for structural changes. A reliable estimate of the beta-decay properties in this mass region is a valuable information for evaluating decay rates in astrophysical scenarios.Comment: 11 pages, 12 figure

Attention modulates the processing of emotional expression triggered by foveal faces

To investigate whether the processing of emotional expression for faces presented within foveal vision is modulated by spatial attention, event-related potentials (ERPs) were recorded in response to stimulus arrays containing one fearful or neutral face at fixation, which was flanked by a pair of peripheral bilateral lines. When attention was focused on the central face, an enhanced positivity was elicited by fearful as compared to neutral faces. This effect started at 160 ms post-stimulus, and remained present for the remainder of the 700 ms analysis interval. When attention was directed away from the face towards the line pair, the initial phase of this emotional positivity remained present, but emotional expression effects beyond 220 ms post-stimulus were completely eliminated. These results demonstrate that when faces are presented foveally, the initial rapid stage of emotional expression processing is unaffected by attention. In contrast, attentional task instructions are effective in inhibiting later, more controlled stages of expression analysis

Evidence for fresh frost layer on the bare nucleus of comet Hale--Bopp at 32 AU distance

Here we report that the activity of comet Hale--Bopp ceased between late 2007 and March, 2009, at about 28 AU distance from the Sun. At that time the comet resided at a distance from the Sun that exceeded the freeze-out distance of regular comets by an order of magnitude. A Herschel Space Observatory PACS scan was taken in mid-2010, in the already inactive state of the nucleus. The albedo has been found to be surprisingly large (8.1$\pm$0.9%{}), which exceeds the value known for any other comets. With re-reduction of archive HST images from 1995 and 1996, we confirm that the pre-perihelion albedo resembled that of an ordinary comet, and was smaller by a factor of two than the post-activity albedo. Our further observations with the Very Large Telescope (VLT) also confirmed that the albedo increased significantly by the end of the activity. We explain these observations by proposing gravitational redeposition of icy grains towards the end of the activity. This is plausible for such a massive body in a cold environment, where gas velocity is lowered to the range of the escape velocity. These observations also show that giant comets are not just the upscaled versions of the comets we know but can be affected by processes that are yet to be fully identified.Comment: 7 pages, 6 figures, accepted for publication in Ap

Issues in management of artificial intelligence based projects

Now that Artificial Intelligence (AI) is gaining acceptance, it is important to examine some of the obstacles that still stand in the way of its progress. Ironically, many of these obstacles are related to management and are aggravated by the very characteristcs that make AI useful. The purpose of this paper is to heighten awareness of management issues in AI development and to focus attention on their resolution

Charlie and the CryptoFactory: Towards Secure and Trusted Manufacturing Environments

The modernisation that stems from Industry 4.0 started populating the manufacturing sector with networked devices, complex sensors, and a significant proportion of physical actuation components. However, new capabilities in networked cyber-physical systems demand more complex infrastructure and algorithms and often lead to new security flaws and operational risks that increase the attack surface area exponentially. The interconnected nature of Industry 4.0-driven operations and the pace of digital transformation mean that cyber-attacks can have far more extensive effects than ever before. Based on that, the core ideas of this paper are driven by the observation that cyber security is one of the key enablers of Industry 4.0. Having this in mind, we propose CryptoFactory – a forward looking design of a layered-based architecture that can be used as a starting point for building secure and privacy-preserving smart factories. CryptoFactory aims to change the security outlook in smart manufacturing by discussing a set of fundamental requirements and functionality that modern factories should support in order to be resistant to both internal and external attacks. To this end, CryptoFactory first focuses on how to build trust relationships between the hardware devices in the factory. Then, we look on how to use several cryptographic approaches to allow IoT devices to securely collect, store and share their data while we also touch upon the emerging topic of secure and privacy-preserving communication and collaboration between manufacturing environments and value chains. Finally, we look into the problem of how to perform privacy-preserving analytics by leveraging Trusted Execution Environments and the promising concept of Functional Encryption