A solid state spin-wave quantum memory for time-bin qubits

We demonstrate the first solid-state spin-wave optical quantum memory with on-demand read-out. Using the full atomic frequency comb scheme in a \PrYSO crystal, we store weak coherent pulses at the single-photon level with a signal to noise ratio $> 10$. Narrow-band spectral filtering based on spectral hole burning in a second \PrYSO crystal is used to filter out the excess noise created by control pulses to reach an unconditional noise level of $(2.0 \pm 0.3) \times10^{-3}$ photons per pulse. We also report spin-wave storage of photonic time-bin qubits with conditional fidelities higher than a measure and prepare strategy, demonstrating that the spin-wave memory operates in the quantum regime. This makes our device the first demonstration of a quantum memory for time-bin qubits, with on demand read-out of the stored quantum information. These results represent an important step for the use of solid-state quantum memories in scalable quantum networks.Comment: 10 pages, 10 figure

Ácidos grasos, bioactivos y actividades antioxidante y antimicrobiana de Ankyropetalum spp., una nueva fuente de ácido nervónico

Ankyropetalum extracts were obtained by using two different extractors (Soxhlet and ultrasonic bath). The phenol, flavonoid, DPPH, FRAP, and antimicrobial activity properties of the extracts were investigated. In addition, the fatty acid composition was determined in GC-MS. High values were found in A. reuteri and A. gypsophiloides for total phenolic and flavonoid contents, respectively. DPPH and FRAP values were high in A. arsusianum and A. gypsophiloides, respectively. Better results were obtained by using methanol as the solvent and soxhlet as the extractor. The results showed that the extracts seem to be reasonably effective against test organisms including clinical isolates. The most promising results were obtained with all species USB extracts against Candida parapsilosis. It is notable that the levels of nervonic acid in A. arsusianum and A. reuteri reached 40%. Unlike other sources of nervonic acid in the world, the absence of erucic acid in plant oil increases the value of these plants.Los extractos de Ankyropetalum se obtuvieron usando dos medios de extracción diferentes (Soxhlet y baño ultrasónico). A estos extractos se les determinó el contenido fenólico, flavonoides, DPPH, FRAP, y la actividad antimicrobiana. Además, se determinó la composición de ácidos grasos mediante GC-MS. Se encontraron valores altos de contenido fenólico y flavonoide total en A. reuteri y A. gypsophiloides, respectivamente. Los valores de DPPH y FRAP fueron altos en A. arsusianum y A. gypsophiloides, respectivamente. Se obtuvieron mejores resultados utilizando metanol como disolvente y Soxhlet como extractor. Los resultados mostraron que los extractos parecen ser razonablemente efectivos contra los organismos ensayados, incluidos los aislados clínicos. Los resultados más prometedores se obtuvieron con todos los extractos USB de especies contra la Cándida parapsilosis. Es notable que los niveles de ácido nervónico en A. arsusianum y A. reuteri alcanzaron el 40%. A diferencia de otras fuentes de ácido nervónico en el mundo, la ausencia de ácido erúcico en el aceite vegetal aumenta el valor de estas plantas

Storage of up-converted telecom photons in a doped crystal

We report on an experiment that demonstrates the frequency up-conversion of telecommunication wavelength single-photon-level pulses to be resonant with a $\mathrm{Pr}^{3+}$:$\mathrm{Y}_2\mathrm{Si}\mathrm{O}_5$ crystal. We convert the telecom photons at $1570\,\mathrm{nm}$ to $606\,\mathrm{nm}$ using a periodically-poled potassium titanyl phosphate nonlinear waveguide. The maximum device efficiency (which includes all optical loss) is inferred to be $\eta_{\mathrm{dev}}^{\mathrm{max}} = 22 \pm 1\,$ (internal efficiency $\eta_{\mathrm{int}} = 75\pm8\,$) with a signal to noise ratio exceeding 1 for single-photon-level pulses with durations of up to 560$\,$ns. The converted light is then stored in the crystal using the atomic frequency comb scheme with storage and retrieval efficiencies exceeding $\eta_{\mathrm{AFC}} = 20\,$ for predetermined storage times of up to $5\,\mu\mathrm{s}$. The retrieved light is time delayed from the noisy conversion process allowing us to measure a signal to noise ratio exceeding 100 with telecom single-photon-level inputs. These results represent the first demonstration of single-photon-level optical storage interfaced with frequency up-conversion

Feedback control of electrical stimulation electrode arrays

Electrical stimulation electrode arrays are an emerging technology that enables muscles to be artificially contracted through the activation of their associated motor neurons. A principal application of electrical stimulation is to assist human motion for orthotic or therapeutic purposes. This paper develops a framework for the design of model-based electrode array feedback controllers that balance joint angle tracking performance with the degree of disturbance and modeling mismatch that can exist in the true underlying biomechanical system. This framework is used to develop a simplified control design procedure that is suitable for application in a clinical setting. Experimental results evaluate the feasibility of the control design approach through tests on ten participants using both fabric and polycarbonate electrode arrays

A spectral hole memory for light at the single photon level

We demonstrate a solid state spin-wave optical memory based on stopped light in a spectral hole. A long lived narrow spectral hole is created by optical pumping in the inhomogeneous absorption profile of a Pr$^{3+}$:Y$_2$SiO$_5$ crystal. Optical pulses sent through the spectral hole experience a strong reduction of their group velocity and are spatially compressed in the crystal. A short Raman pulse transfers the optical excitation to the spin state before the light pulse exits the crystal, effectively stopping the light. After a controllable delay, a second Raman pulse is sent, which leads to the emission of the stored photons. We reach storage and retrieval efficiencies for bright pulses of up to $39\,\%$ in a $5 \,\mathrm{mm}$-long crystal. We also show that our device works at the single photon level by storing and retrieving $3\,\mathrm{\mu s}$-long weak coherent pulses with efficiencies up to $31\,\%$, demonstrating the most efficient spin-wave solid state optical memory at the single-photon level so far. We reach an unconditional noise level of $(9\pm1)\times 10^{-3}$ photons per pulse in a detection window of $4\,\mathrm{\mu s}$ leading to a signal-to-noise ratio of $33 \pm 4$ for an average input photon number of 1, making our device promising for long-lived storage of non-classical light.Comment: 5 pages, 4 figure

Combining electrical stimulation mediated by iterative learning control with movement practice using real objects and simulated tasks for post-stroke upper extremity rehabilitation.

Objective: Task specific training and Electrical Stimulation (ES) are techniques used in rehabilitation of the upper extremity post stroke. This study describes the feasibility of using a rehabilitation system that combines personalised, precisely controlled levels of ES to the anterior deltoid, triceps and finger and wrist extensors during goal-oriented activity utilising real objects from daily life. Materials and Methods:Four chronic stroke participants undertook seventeen intervention sessions, each of one hour duration. During each session, particpants performed goal -orientated tasks while Iterative learning control (ILC) updated the ESsignal applied to each muscle group. The update was based on the difference between the ideal and actual movement in the previous attempt at the task, measured using Microsoft Kinect and PrimeSense sensors. The control system applied the minimum amount of ES required with a view to facilitating success at each given task while maximising voluntary effort. Results: Preliminary results demonstrate that ES mediated by ILC resulted in a statistically significant improvement in range of movement in all four joint angles studied (shoulder flexion; elbow, wrist and index finger extension) over 17 intervention sessions. Additionally, participants required signficantly less extrinsic support for each task. The tasks and system is described and initial intervention data are reported. Discussion: The feasibility of using this system for assisting upper limb movement has been demonstrated. A large scale pilot RCT is now required

Effects of drinking water treatment sludge on crop quality of zea mays L.

This research was conducted to evaluate effects of drinking water treatment sludge on crop quality. In this trial Zea mays L. (pioneer 32 w 86) was used, and the research was planned according to random blocks sampling design with three replicates. Increased amount of sludge, as of 0, 1, 2, 3, 4 t da-1, was applied on blocks. Zea mays L. seeds were sewed between rows within a distance of 65 cm, and on rows within a distance of 25 cm. Blocks were irrigated to stimulate germination during dry conditions. When the numbers of leaves were reached 8, 10 kg da-1 of N fertilizer was applied. Plant length, first corncob height, corncob length, corncob diameter and number of corncob were observed and measured using randomly selected 10 plants from each block. As a result, the highest plant length, 206.97 cm, was found on blocks of control. The lowest plant length 189.76 cm was found on blocks with 1 t da-1. The highest first corncob height, 85.62 cm, was found on blocks with 1 t da-1 sludge applied. The lowest first corncob height, 82.09 cm, was found on blocks with 4 t da-1 sludge applied. Average of the highest corncob number 1.23 was found on blocks with 4 t da-1 sludge applied. Average of the lowest corncob number 1.03 was found on blocks with 1 t da-1 sludge applied. The highest corncob length 22.08 cm was found on blocks with 2 t da-1 sludge applied. The lowest corncob length 19.94 cm was found on blocks with 3 t da-1 sludge applied. The highest corncob diameter 4.15 cm was found on blocks with 0 t da-1 sludge applied. The lowest corncob diameter 3.86 cm was found on blocks with 1 t da-1 sludge applied

Psychometric validation of the Turkish nine-item Internet Gaming Disorder Scale–Short Form (IGDS9-SF)

The main aims of the current study were to test the factor structure, reliability and validity of the nine-item Internet Gaming Disorder Scale-Short Form (IGDS9- SF), a standardized measure to assess symptoms and prevalence of Internet Gaming Disorder (IGD). In the present study participants were assessed with the IGDS9-SF, nine-item Internet Gaming Disorder Scale (IGDS) and the Young's Internet Addiction Test-Short Form (YIAT-SF). Confirmatory factor analyses demonstrated that the factor structure (i.e., the dimensional structure) of the IGDS9-SF was satisfactory. The scale was also reliable (i.e., internally consistent with a Cronbach's alpha of 0.89) and showed adequate convergent and criterion-related validity, as indicated by statistically significant positive correlations between average time daily spent playing games during last year, IGDS and YIAT-SF scores. By applying the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) threshold for diagnosing IGD (e.g., endorsing at least five criteria), it was found that the prevalence of disordered gamers ranged from 0.96% (whole sample) to 2.57% (e-sports players). These findings support the Turkish version of the IGDS9-SF as a valid and reliable tool for determining the extent of IGD-related problems among young adults and for the purposes of early IGD diagnosis in clinical settings and similar research

Spor Bilimlerinde Hareket Yakalama Teknolojisi: Kinect ile Üç Boyutlu Sanal Spor Platformu

Düzenli spor yapmanın yaşam ve sağlık kalitesi için yararlı olduğu kabul edilmektedir. Fakat düzenli spor yapma olanaklarının özellikle gelişmekte olan ülkelerde yeterince yaygınlaşmadığı gözlenmektedir. İnternet ve Kinect gibi güncel ve gelişmiş teknolojilerin sağladığı olanaklar ile, spor yapamayanlara fiziksel olarak aynı ortamda bulunmaksızın, sanal eğitmen kontrolünde spor yapabilme olanağı sunmanın alternatif bir çözüm yaratabileceği düşünülmektedir. Bu doğrultudaki çalışmalarla, Kinect üç boyutlu sanal spor platformu tasarlanıp geliştirilmiştir. Geliştirilen platformun özellikleri, yeni teknolojilerin avantajlarının kullanıldığı platformlar ile alternatif spor yapma olanakları gözden geçirilmektedirRegular sports activity is considered to be beneficial for life quality and health. On the other hand, regular sporting opportunities are not widespread, especially in developing countries. It may be possible to provide an alternative solution for physical activity in the control of a virtual instructor, without being physically in the same place, thanks to the facilities provided by technologies such as Internet and Kinect. In this respect, the three dimensional virtual sports platform Kinect was designed and developed. The different features of the platform are described, and the advantages of new technology achievement and possibilities of alternative sports practice are give