The minimal spectral radius with given independence number

In this paper, we determine the graphs which have the minimal spectral radius among all the connected graphs of order $n$ and the independence number $\lceil\frac{n}{2}\rceil-1.$Comment: 14 page

Scalable accelerator for nonuniform multi-word log-quantized neural network

Department of Electrical EngineeringLogarithmic quantization has many hardware-friendly features, but its lower accuracy in certain conditions has prevented more widespread use. Recently modified schemes have been proposed to solve the accuracy problem without compromising its hardware efficiency by selectively employing multiple words. This however causes variable-latency multiplication, demanding a new hardware architecture to support efficient mapping of large neural network layers as well as various types of convolution layers such as depthwise separable convolution. In this paper we present a novel hardware architecture for nonuniform multi-word log-quantized neural networks that is scalable with the number of processing elements while maximizing data reuse. Our architecture supports depthwise convolution and pointwise convolution as well as 3D convolution, which are important for recent mobile-friendly networks. We also propose a hardware-software cooperative optimization to reduce the impact of variable-latency multiplication on performance. Our experimental results using various convolution layers from MobileNetV2 demonstrate the speed advantage of our architecture and high scalability with the number of PEs, compared with previous architectures for depthwise separable convolution or log quantization. Our results also show that our optimization is very effective in improving the performance of our architecture.clos

Infrared optical absorption spectra of CuO single crystals: Fermion-spinon band and dimensional crossover of the antiferromagnetic order

We have obtained mid-infrared optical absorption spectra of the S=1/2 quasi one-dimensional CuO using polarized transmission measurement and interpreted the spectra in terms of phonon assisted magnetic excitations. When the electric field is parallel to the main antiferromagnetic direction a Delta shaped peak is observed with the maximum at 0.23eV which is attributed to spinons along Cu-O chains. At low temperatures in the antiferromagnetic phase another peak appears at 0.16eV which is attributed to two-magnon absorption but the spinon peak remains. This behavior is interpreted as due to a dimensional crossover where the low temperature three-dimensional magnetic phase keeps short range characteristics of a one-dimensional magnet.Comment: 5 pages, 5 figure

DEVELOPMENT AND EVALUATION OF A NOVEL TAEKWONDO CHEST PROTECTOR TO IMPROVE MOBILITY WHEN PERFORMING AXE KICKS

The axe kick, in Olympic style taekwondo, has been identified as the most popular scoring technique aimed to the head during full contact competition. The first purpose of this study was to identify and investigate design issues with the current World Taekwondo Federation approved chest protector. A secondary purpose was to develop a novel chest protector addressing the identified design issues and to conduct a biomechanical analysis. Fifteen male elite Taekwondo players were selected to perform three different styles of the axe kick, i.e., front, in-out, and out-in axe kick five times each for a total of 45 kicks. Two-way repeated measures ANOVA showed significant differences between the novel and existing chest protector conditions for vertical height of the toe, downward kicking foot speed, hip flexion angle and ipsilateral shoulder flexion extension range of motion (ROM) (p0.05). These results indicate that the novel chest protector interferes less with both the lower and upper limbs during the performance of the axe kick and provides a more natural, free-moving alternative to the current equipment used

SALM5 trans-synaptically interacts with LAR-RPTPs in a splicing-dependent manner to regulate synapse development

Synaptogenic adhesion molecules play critical roles in synapse formation. SALM5/Lrfn5, a SALM/Lrfn family adhesion molecule implicated in autism spectrum disorders (ASDs) and schizophrenia, induces presynaptic differentiation in contacting axons, but its presynaptic ligand remains unknown. We found that SALM5 interacts with the Ig domains of LAR family receptor protein tyrosine phosphatases (LAR-RPTPs; LAR, PTPδ, and PTPσ). These interactions are strongly inhibited by the splice insert B in the Ig domain region of LAR-RPTPs, and mediate SALM5-dependent presynaptic differentiation in contacting axons. In addition, SALM5 regulates AMPA receptor-mediated synaptic transmission through mechanisms involving the interaction of postsynaptic SALM5 with presynaptic LAR-RPTPs. These results suggest that postsynaptic SALM5 promotes synapse development by trans-synaptically interacting with presynaptic LAR-RPTPs and is important for the regulation of excitatory synaptic strength

Biopsychosocial factors of gaming disorder: a systematic review employing screening tools with well-defined psychometric properties

Background and aimsConsidering the growing number of gamers worldwide and increasing public concerns regarding the negative consequences of problematic gaming, the aim of the present systematic review was to provide a comprehensive overview of gaming disorder (GD) by identifying empirical studies that investigate biological, psychological, and social factors of GD using screening tools with well-defined psychometric properties.Materials and methodsA systematic literature search was conducted through PsycINFO, PubMed, RISS, and KISS, and papers published up to January 2022 were included. Studies were screened based on the GD diagnostic tool usage, and only five scales with well-established psychometric properties were included. A total of 93 studies were included in the synthesis, and the results were classified into three groups based on biological, psychological, and social factors.ResultsBiological factors (n = 8) included reward, self-concept, brain structure, and functional connectivity. Psychological factors (n = 67) included psychiatric symptoms, psychological health, emotion regulation, personality traits, and other dimensions. Social factors (n = 29) included family, social interaction, culture, school, and social support.DiscussionWhen the excess amount of assessment tools with varying psychometric properties were controlled for, mixed results were observed with regards to impulsivity, social relations, and family-related factors, and some domains suffered from a lack of study results to confirm any relevant patterns.ConclusionMore longitudinal and neurobiological studies, consensus on a diagnostic tool with well-defined psychometric properties, and an in-depth understanding of gaming-related factors should be established to settle the debate regarding psychometric weaknesses of the current diagnostic system and for GD to gain greater legitimacy in the field of behavioral addiction

Transcranial direct current stimulation for online gamers: A prospective single-arm feasibility study

Aim: Excessive use of online games can have negative influences on mental health and daily functioning. Although the effects of transcranial direct current stimulation (tDCS) have been investigated for the treatment of addiction, it has not been evaluated for excessive online game use. This study aimed to investigate the feasibility and tolerability of tDCS over the dorsolateral prefrontal cortex (DLPFC) in online gamers. Methods: A total of 15 online gamers received 12 active tDCS sessions over the DLPFC (anodal left/cathodal right, 2 mA for 30 min, 3 times per week for 4 weeks). Before and after tDCS sessions, all participants underwent 18F-fluoro-2-deoxyglucose positron emission tomography scans and completed the Internet Addiction Test (IAT), Brief Self Control Scale (BSCS), and Beck Depression Inventory-II (BDI-II). Results: After tDCS sessions, weekly hours spent on games (p = .02) and scores of IAT (p < .001) and BDI-II (p = .01) were decreased, whereas BSCS score was increased (p = .01). Increases in self-control were associated with decreases in both addiction severity (p = .002) and time spent on games (p = .02). Moreover, abnormal right-greater-than-left asymmetry of regional cerebral glucose metabolism in the DLPFC was partially alleviated (p = .04). Conclusions: Our preliminary results suggest that tDCS may be useful for reducing online game use by improving interhemispheric balance of glucose metabolism in the DLPFC and enhancing self-control. Larger sham-controlled studies with longer follow-up period are warranted to validate the efficacy of tDCS in gamers

Serial Monitoring of Immune Markers Being Represented Regulatory T Cell/T Helper 17 Cell Ratio: Indicating Tolerance for Tapering Immunosuppression after Liver Transplantation

Recipients of liver transplantation (LT) require long-term immunosuppressive drug treatment, but lifelong immunosuppressive treatment has severe side effects. It is known that some LT recipients develop immune tolerance, and although the development of such operational tolerance should allow a decrease in the burden of immunosuppressive drug treatment, the factors that indicate operational tolerance are not clear. This study aimed to monitor immunological markers over time in LT recipients to identify those markers indicating the development of operational tolerance. We performed a prospective pilot study measuring immune markers, including the ratio of regulatory T (Treg) and T helper (Th) 17 cells in peripheral blood in the 14 most immunologically stable patients among 70 clinically stable LT recipients. The doses of immunosuppressive drugs given to these 14 LT recipients were tapered over time and they were monitored for immunological markers related to the development of immune tolerance. As the doses of immunosuppressive drugs were reduced, the Treg/Th17, Th1/Th17, and CD8/Th17 ratio in tolerant recipients was significantly increased compared with that of nontolerant recipients. These results suggest that monitoring of changes in the immune makers, including Treg/Th17 ratio during tapering of immunosuppression may allow prediction of the development of tolerance

Regulation of synaptic Rac1 activity, long-term potentiation maintenance, and learning and memory by BCR and ABR Rac GTPase-activating proteins

Rho family small GTPases are important regulators of neuronal development. Defective Rho regulation causes nervous system dysfunctions including mental retardation and Alzheimer's disease. Rac1, a member of the Rho family, regulates dendritic spines and excitatory synapses, but relatively little is known about how synaptic Rac1 is negatively regulated. Breakpoint cluster region (BCR) is a Rac GTPase-activating protein known to form a fusion protein with the c-Abl tyrosine kinase in Philadelphia chromosome-positive chronic myelogenous leukemia. Despite the fact that BCR mRNAs are abundantly expressed in the brain, the neural functions of BCR protein have remained obscure. We report here that BCR and its close relative active BCR-related (ABR) localize at excitatory synapses and directly interact with PSD-95, an abundant postsynaptic scaffolding protein. Mice deficient for BCR or ABR show enhanced basal Rac1 activity but only a small increase in spine density. Importantly, mice lacking BCR or ABR exhibit a marked decrease in the maintenance, but not induction, of long-term potentiation, and show impaired spatial and object recognition memory. These results suggest that BCR and ABR have novel roles in the regulation of synaptic Rac1 signaling, synaptic plasticity, and learning and memory, and that excessive Rac1 activity negatively affects synaptic and cognitive functions.This work was supported by the National Creative Research Initiative Program of the Korean Ministry of Education, Science and Technology (E.K.), Neuroscience Program Grant 2009-0081468 (S.-Y.C.), 21st Century Frontier R&D Program in Neuroscience Grant 2009K001284 (H.K.), Basic Science Research Program Grant R13-2008-009-01001-0 (Y.C.B.), and United States Public Health Service Grants HL071945 (J.G.) and HL060231 (J.G., N.H.)