125 research outputs found

    Programming multi-level quantum gates in disordered computing reservoirs via machine learning and TensorFlow

    Get PDF
    Novel machine learning computational tools open new perspectives for quantum information systems. Here we adopt the open-source programming library TensorFlow to design multi-level quantum gates including a computing reservoir represented by a random unitary matrix. In optics, the reservoir is a disordered medium or a multi-modal fiber. We show that trainable operators at the input and the readout enable one to realize multi-level gates. We study various qudit gates, including the scaling properties of the algorithms with the size of the reservoir. Despite an initial low slop learning stage, TensorFlow turns out to be an extremely versatile resource for designing gates with complex media, including different models that use spatial light modulators with quantized modulation levels.Comment: Added a new section and a new figure about implementation of the gates by a single spatial light modulator. 9 pages and 4 figure

    Adiabatic evolution on a spatial-photonic Ising machine

    Get PDF
    Combinatorial optimization problems are crucial for widespread applications but remain difficult to solve on a large scale with conventional hardware.Novel optical platforms, knownas coherent or photonic Ising machines, are attracting considerable attention as accelerators on optimization tasks formulable as Ising models. Annealing is a well-known technique based on adiabatic evolution for finding optimal solutions in classical and quantum systems made by atoms, electrons, or photons. Although various Ising machines employ annealing in some form, adiabatic computing on optical settings has been only partially investigated.Here, we realize the adiabatic evolution of frustrated Ising models with 100 spins programmed by spatial light modulation. We use holographic and optical control to change the spin couplings adiabatically, and exploit experimental noise to explore the energy landscape. Annealing enhances the convergence to the Ising ground state and allows to find the problem solution with probability close to unity.Our results demonstrate a photonic scheme for combinatorial optimization in analogy with adiabatic quantum algorithms and classical annealing methods but enforced by optical vector-matrix multiplications and scalable photonic technology

    Biofeedback in the prophylactic treatment of medication overuse headache: a pilot randomized controlled trial

    Get PDF
    Abstract Background: Medication overuse headache (MOH) is a major clinical concern and a common health risk. Recent literature stressed the need to manage chronic headache by using integrated biobehavioral approaches. Few studies evaluated how biofeedback can be useful in MOH. The aim of the study is to evaluate in a randomized, controlled, single-blind trial the effects of biofeedback associated with traditional pharmacological therapy in the prophylactic treatment of MOH. Method: Twenty-seven subjects were randomized to frontal electromyographic (EMG) biofeedback associated with prophylactic pharmacological therapy (Bfb Group) or to pharmacological treatment alone (Control Group). The primary outcome was to evaluate the number of patients that return episodic after treatment. Secondly we evaluate the effects of frontal EMG BFB on frequency of headache and analgesic intake. Changes in coping strategies and in EMG frontalis tension were also evaluated. ANOVA was performed on all the variables of interest. Results: Our results indicate that at the end of treatment the number of patients that returned episodic in the Bfb group was significantly higher than in the Control group. Patients in the Bfb group differed from the Control group in headache frequency, amount of drug intake and active coping with pain. These outcomes were confirmed also after 4 months of follow-up. No significant effects were observed in EMG recordings. Conclusions: Biofeedback added to traditional pharmacological therapy in the treatment of MOH is a promising approach for reducing headache frequency and analgesic intake. Modification of coping cognitions in the Bfb group, as an adjunct mechanism of self-regulation, needs more evaluations to understand the role of biofeedback in changing maladaptive psychophysiological responses

    MISSEL: a method to identify a large number of small species-specific genomic subsequences and its application to viruses classification

    Get PDF
    Continuous improvements in next generation sequencing technologies led to ever-increasing collections of genomic sequences, which have not been easily characterized by biologists, and whose analysis requires huge computational effort. The classification of species emerged as one of the main applications of DNA analysis and has been addressed with several approaches, e.g., multiple alignments-, phylogenetic trees-, statistical- and character-based methods

    Bronchiolitis. Analysis of 10 consecutive epidemic seasons

    Get PDF
    Bronchiolitis is the leading cause of hospitalization in infants under 12 months. Our aims were to analyze epidemiological characteristics of infants with bronchiolitis over 10 consecutive seasons and to evaluate whether there are any clinical differences between infants hospitalized for bronchiolitis during epidemic peak months and infants in non-peak months. We enrolled consecutive enrolled 723 previously healthy term infants hospitalized at the Paediatric Emergency Department, "Sapienza" University of Rome over the period 2004-2014. Fourteen respiratory viruses were detected from nasopharyngeal aspirates by molecular methods. Clinical and demographic data were extracted from clinical charts. Viruses were detected in 351 infants (48.5%): RSV in 234 (32.4%), RV in 44 (6.1%), hBoV in 11 (1.5%), hMPV in 12 (1.6%), co-infections in 39 (5.4%), and other viruses in 11 (1.5%). Analyzing the 10 epidemic seasons, we found higher incidence for bronchiolitis every 4 years with a peak during the months December-January. Infants hospitalized during peak months had lower family history for asthma (P = 0.003), more smoking mothers during pregnancy (P = 0.036), were slightly higher breastfed (0.056), had lower number of blood eosinophils (P = 0.015) and had a higher clinical severity score (P = 0.017). RSV was detected mostly during peak months, while RV was equally distributed during the seasons. We found some variations in bronchiolitis incidence during epidemics, and discriminative characteristics in infants hospitalized for bronchiolitis during peak months and in non-peak months, that might reflect two different populations of children. Pediatr Pulmonol. 2016; 9999:XX-XX. © 2016 Wiley Periodicals, Inc

    Noninvasive vagus nerve stimulation as acute therapy for migraine. The randomized PRESTO study

    Get PDF
    Objective: To evaluate the efficacy, safety, and tolerability of noninvasive vagus nerve stimulation (nVNS; gammaCore; electroCore, LLC, Basking Ridge, NJ) for the acute treatment of migraine in a multicenter, double-blind, randomized, sham-controlled trial. Methods: A total of 248 participants with episodic migraine with/without aura were randomized to receive nVNS or sham within 20 minutes from pain onset. Participants were to repeat treatment if pain had not improved in 15 minutes. Results: nVNS (n = 120) was superior to sham (n = 123) for pain freedom at 30 minutes (12.7% vs 4.2%; p = 0.012) and 60 minutes (21.0% vs 10.0%; p = 0.023) but not at 120 minutes (30.4% vs 19.7%; p = 0.067; primary endpoint; logistic regression) after the first treated attack. A post hoc repeatedmeasures test provided further insight into the therapeutic benefit of nVNS through 30, 60, and 120 minutes (odds ratio 2.3; 95% confidence interval 1.2, 4.4; p = 0.012). nVNS demonstrated benefits across other endpoints including pain relief at 120minutes and was safe and well-tolerated. Conclusion: This randomized sham-controlled trial supports the abortive efficacy of nVNS as early as 30 minutes and up to 60 minutes after an attack. Findings also suggest effective pain relief, tolerability, and practicality of nVNS for the acute treatment of episodic migraine

    Non-24-hour sleep-wake rhythm disorder and melatonin secretion impairment in a patient with pineal cyst

    Get PDF
    We report the case of a 14-year-old girl with a wide non-compressive pineal cyst, associated with the inability to control her sleep-wake schedule. Actigraphic monitoring showed a 24-hour free-running disorder (tau 26.96 hours). A 24-hour serum melatonin curve assay, with concomitant video-polysomnographic and body-core temperature monitoring, was performed. Melatonin curve showed a blunted nocturnal peak, lower total quantity of melatonin, and prolonged melatonin secretion in the morning, with normal temperature profile and sleep parameters. Treatment with melatonin up to 14 mg at bedtime was initiated with complete realignment of the sleep-wake rhythm (tau 23.93 hours). The role of the pineal cyst in the aforementioned alteration of melatonin secretion and free-running disorder remains controversial, but our case supports the utility of monitoring sleep/wake, temperature, and melatonin rhythms in the diagnostic work-up of pineal cysts associated with free-running disorder

    Study of hypothalamic metabolism in cluster headache by proton MR spectroscopy

    Get PDF
    The authors used 1H-MRS to investigate hypothalamic metabolism in 26 patients with cluster headache (CH) and 12 healthy subjects. Hypothalamic N-acetylaspartate/creatine was reduced in patients with CH vs controls (p < 0.01). Dividing the patients into episodic CH outside- and in-cluster periods and chronic CH, the hypothalamic N-acetylaspartate/creatine in all three subgroups of patients was reduced. The reduction of the neuronal marker N-acetylaspartate is consistent with hypothalamic neuronal dysfunction in patients with CH
    • …
    corecore