Phantom Space-times in Fake Supergravity

We discuss phantom metrics admitting Killing spinors in fake N=2, D=4 supergravity coupled to vector multiplets. The Abelian U(1) gauge fields in the fake theory have kinetic terms with the wrong sign. We solve the Killing spinor equations for the standard and fake theories in a unified fashion by introducing a parameter which distinguishes between the two theories. The solutions found are fully determined in terms of algebraic conditions, the so-called stabilisation equations, in which the symplectic sections are related to a set of functions. These functions are harmonic in the case of the standard supergravity theory and satisfy the wave-equation in flat (2+1)-space-time in the fake theory. Explicit examples are given for the minimal models with quadratic prepotentials.Comment: 11 page

A Lightweight McEliece Cryptosystem Co-processor Design

Due to the rapid advances in the development of quantum computers and their susceptibility to errors, there is a renewed interest in error correction algorithms. In particular, error correcting code-based cryptosystems have reemerged as a highly desirable coding technique. This is due to the fact that most classical asymmetric cryptosystems will fail in the quantum computing era. Quantum computers can solve many of the integer factorization and discrete logarithm problems efficiently. However, code-based cryptosystems are still secure against quantum computers, since the decoding of linear codes remains as NP-hard even on these computing systems. One such cryptosystem is the McEliece code-based cryptosystem. The original McEliece code-based cryptosystem uses binary Goppa code, which is known for its good code rate and error correction capability. However, its key generation and decoding procedures have a high computation complexity. In this work we propose a design and hardware implementation of an public-key encryption and decryption co-processor based on a new variant of McEliece system. This co-processor takes the advantage of the non-binary Orthogonal Latin Square Codes to achieve much smaller computation complexity, hardware cost, and the key size.Comment: 2019 Boston Area Architecture Workshop (BARC'19

A lightweight McEliece cryptosystem co-processor design

Due to the rapid advances in the development of quantum computers and their susceptibility to errors, there is a renewed interest in error correction algorithms. In particular, error correcting code-based cryptosystems have reemerged as a highly desirable coding technique. This is due to the fact that most classical asymmetric cryptosystems will fail in the quantum computing era. Quantum computers can solve many of the integer factorization and discrete logarithm problems efficiently. However, code-based cryptosystems are still secure against quantum computers, since the decoding of linear codes remains as NP-hard even on these computing systems. One such cryptosystem is the McEliece code-based cryptosystem. The original McEliece code-based cryptosystem uses binary Goppa code, which is known for its good code rate and error correction capability. However, its key generation and decoding procedures have a high computation complexity. In this work we propose a design and hardware implementation of an public-key encryption and decryption co-processor based on a new variant of McEliece system. This co-processor takes the advantage of the non-binary Orthogonal Latin Square Codes to achieve much smaller computation complexity, hardware cost, and the key size.Published versio

Post-quantum cryptographic hardware primitives

The development and implementation of post-quantum cryptosystems have become a pressing issue in the design of secure computing systems, as general quantum computers have become more feasible in the last two years. In this work, we introduce a set of hardware post-quantum cryptographic primitives (PCPs) consisting of four frequently used security components, i.e., public-key cryptosystem (PKC), key exchange (KEX), oblivious transfer (OT), and zero-knowledge proof (ZKP). In addition, we design a high speed polynomial multiplier to accelerate these primitives. These primitives will aid researchers and designers in constructing quantum-proof secure computing systems in the post-quantum era.Published versio

Modulation of β-amyloid precursor protein trafficking and processing by the low density lipoprotein receptor family

Amyloid-β peptide (Aβ) accumulation in the brain is an early, toxic event in the pathogenesis of Alzheimer's disease (AD). Aβ is produced by proteolytic processing of a transmembrane protein, β-amyloid precursor protein (APP), by β- and γ-secretases. Mounting evidence has demonstrated that alterations in APP cellular trafficking and localization directly impact its processing to Aβ. Recent studies have shown that members of the low-density lipoprotein receptor family, including LRP, LRP1B, SorLA/LR11, and apolipoprotein E (apoE) receptor 2, interact with APP and regulate its endocytic trafficking. Another common feature of these receptors is their ability to bind apoE, which exists in three isoforms in humans and the presence of the ε4 allele represents a genetic risk factor for AD. In this review, we summarize the current understanding of the function of these apoE receptors with a focus on their role in APP trafficking and processing. Knowledge of the interactions between these distinct low-density lipoprotein receptor family members and APP may ultimately influence future therapies for AD

Entanglement for a Bimodal Cavity Field Interacting with a Two-Level Atom

Negativity has been adopted to investigate the entanglement in a system composed of a two-level atom and a two-mode cavity field. Effects of Kerr-like medium and the number of photon inside the cavity on the entanglement are studied. Our results show that atomic initial state must be superposed, so that the two cavity field modes can be entangled. Moreover, we also conclude that the number of photon in the two cavity mode should be equal. The interaction between modes, namely, the Kerr effect, has a significant negative contribution. Note that the atom frequency and the cavity frequency have an indistinguishable effect, so a corresponding approximation has been made in this article. These results may be useful for quantum information in optics systems.Comment: Accepted by Commun. Theor. Phy

Relationship between loneliness, social isolation and modifiable risk factors for cardiovascular disease: a latent class analysis

Background: There is growing research into the effects of psychological and social factors such as loneliness and isolation on cardiovascular disease (CVD). However, it is unclear whether individuals with particular clusters of CVD risk factors are more strongly affected by loneliness and isolation. This study aimed to identify latent clustering of modifiable risk factors among adults aged 50+ and explore the relationship between loneliness, social isolation and risk factor patterns. Methods: Data from 8218 adults of English Longitudinal Study of Ageing were used in latent class analyses to identify latent classes of cardiovascular risk factors and predictors of class membership. Results: There were four latent classes: low-risk (30.2%), high-risk (15.0%), clinical-risk (42.6%) and lifestyle-risk (12.2%) classes. Loneliness was associated with a greater risk of being in the high-risk class (relative risk ratio (RRR) 2.40, 95%CI 2.40 to 1.96) and lifestyle-risk class (RRR 1.36, 95%CI 1.10 to 1.67) and a lower risk of being in the clinical-risk class (RRR 0.84, 95%CI 0.72 to 0.98) relative to the low-risk class. Social disengagement, living alone and low social contact were also differentially associated with latent class memberships. Conclusion: These findings supplement our existing knowledge of modifiable risk factors for CVD by showing how risk factors cluster together and how the risk patterns are related to social factors, offering important implications for clinical practice and preventive intervention

Loneliness during a strict lockdown: Trajectories and predictors during the COVID-19 pandemic in 38,217 United Kingdom adults

Rationale: There are increasing worries that lockdowns and “stay-at-home” orders due to the COVID-19 pandemic could lead to a rise in loneliness, which is recognised as a major public health concern. But profiles of loneliness during the pandemic and risk factors remain unclear. / Objective: The current study aimed to examine if and how loneliness levels changed during the strict lockdown and to explore the clustering of loneliness growth trajectories. / Methods: Data from 38,217 UK adults in the UCL COVID -19 Social Study (a panel study collecting data weekly during the pandemic) were analysed during the strict lockdown period in the UK (23/03/2020-10/05/2020). The sample was well-stratified and weighted to population proportions of gender, age, ethnicity, education and geographical location. Growth mixture modelling was used to identify the latent classes of loneliness growth trajectories and their predictors. / Results: Analyses revealed four classes, with the baseline loneliness level ranging from low to high. In the first a few weeks of lockdown, loneliness levels increased in the highest loneliness group, decreased in the lowest loneliness group, and stayed relatively constant in the middle two groups. Younger adults (OR=2.17-6.81), women (OR=1.59), people with low income (OR=1.3), the economically inactive (OR=1.3-2.04) and people with mental health conditions (OR=5.32) were more likely to be in highest loneliness class relative to the lowest. Further, living with others or in a rural area, and having more close friends or greater social support were protective. / Conclusions: Perceived levels of loneliness under strict lockdown measures due to COVID-19 were relatively stable in the UK, but for many people these levels were high with no signs of improvement. Results suggest that more efforts are needed to address loneliness

Joint Resource Allocation and Power Control in Heterogeneous Cellular Networks for Smart Grids

The smart grid communication plays a pivotal role in coordinating energy generation, energy transmission, and energy distribution. Cellular technology with long-term evolution (LTE)-based standards has been a preference for smart grid communication networks. However, conventional cellular networks could suffer from radio access network (RAN) congestion when many smart grid devices attempt access simultaneously. Heterogeneous cellular networks (HetNets) are proposed as important techniques to solve this problem because HetNets can alleviate the RAN congestion by off-loading access attempt from a macrocell to small cells. In smart grid, real-time data from phasor measurement units (PMUs) has a stringent delay requirement in order to ensure the stability of the grid. In this paper, we propose a joint resource allocation and power control scheme to improve the end-to-end delay in HetNets by taking into account the simultaneous transmission of PMUs. We formulate the optimization problem as a mixed integer problem and adopt a game-theoretic approach and the best response dynamics algorithm to solve the problem. Simulation results show that the proposed scheme can significantly minimize the end-to-end delay compared to first-in first-out scheduling and round-robin scheduling schemes