Sacrificing Accuracy for Reduced Computation: Cascaded Inference Based on Softmax Confidence

We study the tradeoff between computational effort and accuracy in a cascade of deep neural networks. During inference, early termination in the cascade is controlled by confidence levels derived directly from the softmax outputs of intermediate classifiers. The advantage of early termination is that classification is performed using less computation, thus adjusting the computational effort to the complexity of the input. Moreover, dynamic modification of confidence thresholds allow one to trade accuracy for computational effort without requiring retraining. Basing of early termination on softmax classifier outputs is justified by experimentation that demonstrates an almost linear relation between confidence levels in intermediate classifiers and accuracy. Our experimentation with architectures based on ResNet obtained the following results. (i) A speedup of 1.5 that sacrifices 1.4% accuracy with respect to the CIFAR-10 test set. (ii) A speedup of 1.19 that sacrifices 0.7% accuracy with respect to the CIFAR-100 test set. (iii) A speedup of 2.16 that sacrifices 1.4% accuracy with respect to the SVHN test set

Wearable High Voltage Compliant Current Stimulator for Restoring Sensory Feedback

Transcutaneous Electrical Nerve Stimulation (TENS) is a promising technique for eliciting referred tactile sensations in patients with limb amputation. Although several studies show the validity of this technique, its application in daily life and away from laboratories is limited by the need for more portable instrumentation that guarantees the necessary voltage and current requirements for proper sensory stimulation. This study proposes a low-cost, wearable high-voltage compliant current stimulator with four independent channels based on Components-Off-The-Shelf (COTS). This microcontroller-based system implements a voltage-current converter controllable through a digital-to-analog converter that delivers up to 25 mA to load up to 3.6 kΩ. The high-voltage compliance enables the system to adapt to variations in electrode-skin impedance, allowing it to stimulate loads over 10 kΩ with currents of 5 mA. The system was realized on a four-layer PCB (115.9 mm × 61 mm, 52 g). The functionality of the device was tested on resistive loads and on an equivalent skin-like RC circuit. Moreover, the possibility of implementing an amplitude modulation was demonstrated

The Index-Based Subgraph Matching Algorithm (ISMA): Fast Subgraph Enumeration in Large Networks Using Optimized Search Trees

Subgraph matching algorithms are designed to find all instances of predefined subgraphs in a large graph or network and play an important role in the discovery and analysis of so-called network motifs, subgraph patterns which occur more often than expected by chance. We present the index-based subgraph matching algorithm (ISMA), a novel tree-based algorithm. ISMA realizes a speedup compared to existing algorithms by carefully selecting the order in which the nodes of a query subgraph are investigated. In order to achieve this, we developed a number of data structures and maximally exploited symmetry characteristics of the subgraph. We compared ISMA to a naive recursive tree-based algorithm and to a number of well-known subgraph matching algorithms. Our algorithm outperforms the other algorithms, especially on large networks and with large query subgraphs. An implementation of ISMA in Java is freely available at http://sourceforge.net/projects/isma

Dopamine neuronal loss contributes to memory and reward dysfunction in a model of Alzheimer's disease

Alterations of the dopaminergic (DAergic) system are frequently reported in Alzheimer’s disease (AD) patients and are commonly linked to cognitive and non-cognitive symptoms. However, the cause of DAergic system dysfunction in AD remains to be elucidated. We investigated alterations of the midbrain DAergic system in the Tg2576 mouse model of AD, overexpressing a mutated human amyloid precursor protein (APPswe). Here, we found an age-dependent DAergic neuron loss in the ventral tegmental area (VTA) at pre-plaque stages, although substantia nigra pars compacta (SNpc) DAergic neurons were intact. The selective VTA DAergic neuron degeneration results in lower DA outflow in the hippocampus and nucleus accumbens (NAc) shell. The progression of DAergic cell death correlates with impairments in CA1 synaptic plasticity, memory performance and food reward processing. We conclude that in this mouse model of AD, degeneration of VTA DAergic neurons at pre-plaque stages contributes to memory deficits and dysfunction of reward processing

Genetic pre-participation screening in selected athletes: a new tool for the prevention of sudden cardiac death?

Sudden cardiac death (SCD) of athletes is a topical issue. “Borderline cardiac abnormalities”, which occur in ~2% of elite male athletes, may result in SCD, which may have a genetic base. Genetic analysis may help identify pathological cardiac abnormalities. We performed phenotype-guided genetic analysis in athletes who, pre-participation, showed ECG and/or echo “borderline” abnormalities, to discriminate subjects at a greater risk of SCD. Methods: We studied 24 elite athletes referred by the National Federation of Olympic sports; and 25 subjects seeking eligibility to practice agonistic sport referred by the Osservatorio Epidemiologico della Medicina dello Sport della Regione Campania. Inclusion criteria: a) ECG repolarization borderline abnormalities; b) benign ventricular arrhythmias; c) left ventricular wall thickness in the grey zone of physiology versus pathology (max wall thickness 12-15 mm in females; 13-16 mm in males). Based on the suspected phenotype, we screened subjects for the LMNA gene, for 8 sarcomeric genes, 5 desmosomal genes, and cardiac calcium, sodium and potassium channel disease genes. Results: Genetic analysis was completed in 37/49 athletes, 22 competitive and 27 non-competitive athletes, showing “borderline” clinical markers suggestive of hypertrophic cardiomyopathy (HCM,n. 24), dilated cardiomyopathy (n. 4), arrhythmogenic right ventricular dysplasia/cathecholaminergic polymorphic ventricular tachycardia (ARVD/CPVT, n. 11), long QT syndrome (LQTS, n. 4), sick sinus syndrome (SSS, n. 5), Brugada syndrome (BrS, n. 1). We identifyed 11 mutations in 9 athletes (an ARVD athlete was compound heterozygote for the PKP2 gene and an HCM athlete was double heterozygote for the MYBPC3 and TNNT2 genes): 3 known mutations related to LQTS, HCM and ARVD, respectively, and 8 novel mutations, located in the SCN5A, RyR2, PKP2, MYBPC3 and ACTC1 genes. The new mutations were absent in ~800 normal chromosomes and were predicted “probably damaging” by in silico analysis. Patch clamp analysis in channelopathies indicated for some mutation abnormal biophysical behavior of the corresponding mutant protein. Conclusion: Genetic analysis may help distinguish between physiology and pathology in athletes with clinically suspected heart disease

Thermal neutron detection by means of Timepix3

Thermal neutron detection plays a crucial role in numerous scientific and technical applications such as nuclear reactor physics, particle accelerators, radiotherapy,materials analysis and space exploration. There are several challenges associated with the accurate identification and quantification of thermal neutrons. The present work proposes a detailed characterization of a Timepix3 (TPX3) detector equipped with a Lithium Fluoride (6LiF) converter in order to study its response to thermal neutrons that are identified through the 6Li(n,α)3H reaction. The TPX3-based test system has been installed at the HOTNES facility in ENEA and the analysis highlighted its excellent performance showing high effectiveness in the identification of neutrons through morphological analysis of tracks produced by alpha and triton particles, after accurate discrimination from the gamma background. With the use of Monte Carlo simulations, it has been demonstrated that the main contribution is due to tritons and its signal can be used effectively in the identification of thermal neutrons obtaining an efficiency of 0.9 % for 25 meV neutrons. This allows the TPX3 to have important applications as an environmental monitor for thermal neutrons. This monitoring system can be simply realized and is easy to manage because of its compact size and its digital acquisition that allows a real-time analysis

Near infrared light emission quenching in organolanthanide complexes

We investigate the quenching of the near infrared light emission in Er3+ complexes induced by the resonant dipolar interaction between the rare-earth ion and high frequency vibrations of the organic ligand. The nonradiative decay rate of the lanthanide ion is discussed in terms of a continuous medium approximation, which depends only on a few, easily accessible spectroscopic and structural data. The model accounts well for the available experimental results in Er3+ complexes, and predicts an similar to 100% light emission quantum yield in fully halogenated systems

Roadmaps to Utopia: Tales of the Smart City

Notions of the Smart City are pervasive in urban development discourses. Various frameworks for the development of smart cities, often conceptualized as roadmaps, make a number of implicit claims about how smart city projects proceed but the legitimacy of those claims is unclear. This paper begins to address this gap in knowledge. We explore the development of a smart transport application, MotionMap, in the context of a £16M smart city programme taking place in Milton Keynes, UK. We examine how the idealized smart city narrative was locally inflected, and discuss the differences between the narrative and the processes and outcomes observed in Milton Keynes. The research shows that the vision of data-driven efficiency outlined in the roadmaps is not universally compelling, and that different approaches to the sensing and optimization of urban flows have potential for empowering or disempowering different actors. Roadmaps tend to emphasize the importance of delivering quick practical results. However, the benefits observed in Milton Keynes did not come from quick technical fixes but from a smart city narrative that reinforced existing city branding, mobilizing a growing network of actors towards the development of a smart region. Further research is needed to investigate this and other smart city developments, the significance of different smart city narratives, and how power relationships are reinforced and constructed through them

Physiological Responses During Hybrid BNCI Control of an Upper-Limb Exoskeleton

When combined with assistive robotic devices, such as wearable robotics, brain/neural-computer interfaces (BNCI) have the potential to restore the capabilities of handicapped people to carry out activities of daily living. To improve applicability of such systems, workload and stress should be reduced to a minimal level. Here, we investigated the user’s physiological reactions during the exhaustive use of the interfaces of a hybrid control interface. Eleven BNCI-naive healthy volunteers participated in the experiments. All participants sat in a comfortable chair in front of a desk and wore a whole-arm exoskeleton as well as wearable devices for monitoring physiological, electroencephalographic (EEG) and electrooculographic (EoG) signals. The experimental protocol consisted of three phases: (i) Set-up, calibration and BNCI training; (ii) Familiarization phase ; and (iii) Experimental phase during which each subject had to perform EEG and EoG tasks. After completing each task, the NASA-TLX questionnaire and self-assessment manikin (SAM) were completed by the user. We found significant differences (p-value < 0.05) in heart rate variability (HRV) and skin conductance level (SCL) between participants during the use of the two different biosignal modalities (EEG, EoG) of the BNCI. This indicates that EEG control is associated with a higher level of stress (associated with a decrease in HRV) and mental work load (associated with a higher level of SCL) when compared to EoG control. In addition, HRV and SCL modulations correlated with the subject’s workload perception and emotional responses assessed through NASA-TLX questionnaires and SAM