51,643 research outputs found

    Density of states at disorder-induced phase transitions in a multichannel Majorana wire

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    An NN-channel spinless p-wave superconducting wire is known to go through a series of NN topological phase transitions upon increasing the disorder strength. Here, we show that at each of those transitions the density of states shows a Dyson singularity ν(ε)ε1lnε3\nu(\varepsilon) \propto \varepsilon^{-1}|\ln\varepsilon|^{-3} , whereas ν(ε)εα1\nu(\varepsilon) \propto \varepsilon^{|\alpha|-1} has a power-law singularity for small energies ε\varepsilon away from the critical points. Using the concept of "superuniversality" [Gruzberg, Read, and Vishveshwara, Phys. Rev. B 71, 245124 (2005)], we are able to relate the exponent α\alpha to the wire's transport properties at zero energy and, hence, to the mean free path ll and the superconducting coherence length ξ\xi.Comment: 4+1 pages, 3 figure

    Review on Nonoccupational Personal Solar UV Exposure Measurements

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    Solar ultraviolet (UV) radiation follows people during their whole life. Exposure to UV radiation is vital but holds serious risks, too. The quantification of human UV exposure is a complex issue. UV exposure is directly related to incoming UV radiation as well as to a variety of factors such as the orientation of the exposed anatomical site with respect to the sun and the duration of exposure. The use of badge-sensors allows assessing the UV exposure of differently oriented body sites. Such UV devices have been available for over 40 years, and a variety of measuring campaigns have been undertaken since then. This study provides an overview of those studies which reported measurements of the personal UV exposure (PE) during outdoor activities of people not related to their occupation. This overview is given chronologically to show the progress of knowledge in this research and is given with respect to different activities. Special focus is put on the ratio of personal exposure to ambient UV radiation. This ratio, when given as a function of solar elevation, allows estimating PE at any other location or date if ambient UV radiation is known

    Applying Lessons from Cyber Attacks on Ukrainian Infrastructures to Secure Gateways onto the Industrial Internet of Things

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    Previous generations of safety-related industrial control systems were ‘air gapped’. In other words, process control components including Programmable Logic Controllers (PLCs) and smart sensor/actuators were disconnected and isolated from local or wide area networks. This provided a degree of protection; attackers needed physical access to compromise control systems components. Over time this ‘air gap’ has gradually been eroded. Switches and gateways have subsequently interfaced industrial protocols, including Profibus and Modbus, so that data can be drawn from safety-related Operational Technology into enterprise information systems using TCP/IP. Senior management uses these links to monitor production processes and inform strategic planning. The Industrial Internet of Things represents another step in this evolution – enabling the coordination of physically distributed resources from a centralized location. The growing range and sophistication of these interconnections create additional security concerns for the operation and management of safety-critical systems. This paper uses lessons learned from recent attacks on Ukrainian critical infrastructures to guide a forensic analysis of an IIoT switch. The intention is to identify and mitigate vulnerabilities that would enable similar attacks to be replicated across Europe and North America

    Discrimination, Acculturation, Acculturative Stress, and Latino Psychological Distress: A Moderated-Mediational Model

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    Prior research has found that perceived discrimination is associated with adverse mental health outcomes among Latinos. However, the process by which this relationship occurs remains an understudied area. The present study investigated the role of acculturative stress in underlying the relationship between perceived discrimination and Latino psychological distress. Also examined was the ability of acculturation to serve as a moderator between perceived discrimination and acculturative stress. Among a sample of Latino adults (N = 669), moderated mediational analyses revealed that acculturative stress mediated the perceived discrimination-psychological distress relationship, and that the link between perceived discrimination and acculturative stress was moderated by Anglo behavioral orientation but not Latino behavioral orientation. The findings are discussed within a stress and coping perspective that identifies the psychological consequences associated with perceived discrimination and acculturative stress

    Forensic Attacks Analysis and the Cyber Security of Safety-Critical Industrial Control Systems

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    Industrial Control Systems (ICS) and SCADA (Supervisory Control And Data Acquisition) applications monitor and control a wide range of safety-related functions. These include energy generation where failures could have significant, irreversible consequences. They also include the control systems that are used in the manufacture of safety-related products. In this case bugs in an ICS/SCADA system could introduce flaws in the production of components that remain undetected before being incorporated into safety-related applications. Industrial Control Systems, typically, use devices and networks that are very different from conventional IP-based infrastructures. These differences prevent the re-use of existing cyber-security products in ICS/SCADA environments; the architectures, file formats and process structures are very different. This paper supports the forensic analysis of industrial control systems in safety-related applications. In particular, we describe how forensic attack analysis is used to identify weaknesses in devices so that we can both protect components but also determine the information that must be analyzed during the aftermath of a cyber-incident. Simulated attacks detect vulnerabilities; a risk-based approach can then be used to assess the likelihood and impact of any breach. These risk assessments are then used to justify both immediate and longer-term countermeasures

    Geometry of Banach spaces and biorthogonal systems

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    A separable Banach space X contains 1\ell_1 isomorphically if and only if X has a bounded wc_0^*-stable biorthogonal system. The dual of a separable Banach space X fails the Schur property if and only if X has a bounded wc_0^*-biorthogonal system

    Efficacy of Different Pet Treat Formulations to Prevent Infestation by the Mite Tyrophagus putrescentiae

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    The pet food industry is a major part of the high-value processed food market in the USA and worldwide. Pest control associated with pet foods is an important activity. The mite Tyrophagus putrescentiae is a prolific cosmopolitan species that can infests high-value pet treats undetected until the infestations increase to very large numbers. Propylene glycol is a food-safe additive used to prevent mite infestations (Zhang et al., 2018; Abbar et al. 2015). Unfortunately, propylene glycol in certain foods can harm pets, and many companies are changing formulations. Here we conducted forced infestation of mites on three experimental pet treats and compared these to the current product that contains propylene glycol for susceptibility to mite infestation. We confirmed that the current product with propylene glycol did not support any mite population growth after a forced infestation with 20 mites. Two of the test formulations showed promise in preventing mite infestation, but one formulation was clearly susceptible to mites
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