Qutrit Randomized Benchmarking.

Ternary quantum processors offer significant potential computational advantages over conventional qubit technologies, leveraging the encoding and processing of quantum information in qutrits (three-level systems). To evaluate and compare the performance of such emerging quantum hardware it is essential to have robust benchmarking methods suitable for a higher-dimensional Hilbert space. We demonstrate extensions of industry standard randomized benchmarking (RB) protocols, developed and used extensively for qubits, suitable for ternary quantum logic. Using a superconducting five-qutrit processor, we find an average single-qutrit process infidelity of 3.8×10^{-3}. Through interleaved RB, we characterize a few relevant gates, and employ simultaneous RB to fully characterize crosstalk errors. Finally, we apply cycle benchmarking to a two-qutrit CSUM gate and obtain a two-qutrit process fidelity of 0.85. Our results present and demonstrate RB-based tools to characterize the performance of a qutrit processor, and a general approach to diagnose control errors in future qudit hardware.

Prevención y diagnóstico precoz del melanoma con dermatoscopia: una perspectiva biológica / Dermoscopy in the Prevention and Early Diagnosis of Melanoma: A Biological Perspective

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Nanohertz frequency determination for the gravity probe B high frequency superconducting quantum interference device signal.

In this paper, we present a method to measure the frequency and the frequency change rate of a digital signal. This method consists of three consecutive algorithms: frequency interpolation, phase differencing, and a third algorithm specifically designed and tested by the authors. The succession of these three algorithms allowed a 5 parts in 10(10) resolution in frequency determination. The algorithm developed by the authors can be applied to a sampled scalar signal such that a model linking the harmonics of its main frequency to the underlying physical phenomenon is available. This method was developed in the framework of the gravity probe B (GP-B) mission. It was applied to the high frequency (HF) component of GP-B's superconducting quantum interference device signal, whose main frequency f(z) is close to the spin frequency of the gyroscopes used in the experiment. A 30 nHz resolution in signal frequency and a 0.1 pHz/s resolution in its decay rate were achieved out of a succession of 1.86 s-long stretches of signal sampled at 2200 Hz. This paper describes the underlying theory of the frequency measurement method as well as its application to GP-B's HF science signal.

Nódulos eritematosos agrupados en el tronco / Cluster oferyt hematous nodules on the trunk

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Lumbar transplants of immortalized serotonergic neurons alleviate chronic neuropathic pain.

The RN46A cell line was derived from embryonic day 13 rat medullary raphe cells by infection with a retrovirus encoding the temperature-sensitive mutant of SV40 large T antigen. This cell line is neuronally restricted and constitutively differentiates following a shift to non-permissive temperature. Brain-derived neurotrophic factor (BDNF) induced the serotonergic phenotype and increased the survival of RN46A cells in vitro. After transfection of the rat BDNF gene into RN46A cells, an autocrine BDNF-secreting cell line, 46A-B14, was isolated and transplanted into the rat CNS. Transplanted 46A-B14 cells had increased survival and enhanced serotonin (5HT) synthesis compared to 46A-V1 cells, RN46A cells transfected with vector-alone. When 46A-B14 cells were transplanted in the lumbar subarachnoid space of the spinal cord 1 week after a chronic constriction injury (CCI) of the sciatic nerve, they survived longer than 6 weeks on the pia mater. Furthermore, the tactile and cold allodynia and thermal hyperalgesia induced by CCI was significantly reduced during a 4-6- week period. The maximal effect occurred 1 week after transplantation. 46A-V1 cells, transplanted after CCI, did not survive beyond 2-3 weeks and had no effect on the allodynia and hyperalgesia induced by CCI. Acute intrathecal injection of the 5HT receptor antagonist methysergide decreased the antinociceptive effects of the 46A-B14 cells to pre-transplant levels. These data suggest that a chronically applied, low local dose of serotonin near the dorsal horn was able to reverse the development of chronic neuropathic pain following CCI. The use of neural cell lines that are able to deliver inhibitory neurotransmitters such as serotonin, in a model of chronic pain offers a novel approach to pain management.

Cervical spinal cord injury in the adult rat: assessment of forelimb dysfunction.

Traumatic injury to the adult human spinal cord most frequently occurs at the mid-to-low cervical segments and produces tetraplegia. To investigate treatments for improving upper extremity function after cervical spinal cord injury (SCI), three behavioral tests were examined for their potential usefulness in evaluating forelimb function in an adult rat model that mimics human low cervical SCI. Testing was conducted pre- and up to 4 weeks post-operation in adult female rats subjected to either contusion injury at the C7 spinal cord segment or sham-surgery. Modified Forelimb Tarlov scales revealed significant proximal and distal forelimb extension dysfunction in lesion rats at l-to-4 weeks post-cervical SCI. The Forelimb Grip Strength Test showed a significant decrease in forelimb grip strength of lesion rats throughout the 4 weeks post-cervical SCI. Significant deficits in reach and pellet retrieval by lesion rats were measured at l-to-4 weeks post-cervical SCI with the conditioned pellet retrieval Staircase Test. The results demonstrate that these qualitative and quantitative forelimb behavioral tests can be used to evaluate forelimb function following low cervical SCI and may be useful to investigate treatments for improving forelimb function in these lesions.