Span Loss Research Articles

Effect of Edible Coatings on Morphological Characters of Strawberry Fruits

Strawberry (Fragaria × ananassa Duch.) a member of rosaceae family, is a monoecious, short day, succulent, thalamus, perennial herb and quick growing fruit plant. Strawberries are processed into various value-added products such as canned strawberry, jam, jelly, ice cream, wine and other soft drinks. Strawberry is a delicious but delicate fruit with 2-4 days shelf life on ambient condition. Fruit of strawberry are very delicate and highly perishable in nature which resulted very short life span and considerable postharvest loss. The use of edible coating improved the shelf life of strawberry in general compared to untreated control. Significant difference was observed for effect of edible coating on strawberry for all the quality parameter during storage. The fruit weight, width and length decreased in all edible coating treatment. The minimum decrease in fruit weight, Width and length was recorded in treatment T7 (EC + Aloe vera gel 20%) while, the minimum decrease in volume and specific gravity of fruit in the same edible coating.

Natural variation in age-related dopamine neuron degeneration is glutathione dependent and linked to life span

Aging is the biggest risk factor for Parkinson's disease (PD), suggesting that age-related changes in the brain promote dopamine neuron vulnerability. It is unclear, however, whether aging alone is sufficient to cause significant dopamine neuron loss, and if so, how this intersects with PD-related neurodegeneration. Here, through examining a large collection of naturally varying Drosophila strains, we find a strong relationship between life span and age-related dopamine neuron loss. Strains with naturally short-lived animals exhibit a loss of dopamine neurons without generalized neurodegeneration, while animals from long-lived strains retain dopamine neurons across age. Metabolomic profiling reveals lower glutathione levels in short-lived strains which is associated with elevated levels of reactive oxygen species (ROS), sensitivity to oxidative stress, and vulnerability to silencing the familial PD gene parkin. Strikingly, boosting neuronal glutathione levels via glutamate-cysteine ligase (Gcl) overexpression is sufficient to normalize ROS levels, extend life span, and block dopamine neurons loss in short-lived backgrounds, demonstrating that glutathione deficiencies are central to neurodegenerative phenotypes associated with short longevity. These findings may be relevant to human PD pathogenesis, where glutathione depletion is reported to occur in the idiopathic PD patient brain through unknown mechanisms. Building on this, we find reduced expression of the Gcl catalytic subunit in both Drosophila strains vulnerable to age-related dopamine neuron loss and in the human brain from familial PD patients harboring the common LRRK2 G2019S mutation. Our study across Drosophila and human PD systems suggests that glutathione synthesis and levels play a conserved role in regulating age-related dopamine neuron health.

Unrepeatered transmission of single-carrier 800 Gb/s over 447.96 km with simplified third-order ROPA system

Abstract To achieve the longest distance of 800 Gb/s unrepeatered transmission, we use commercial 800 Gb/s transceivers with soft-decision FEC, optimized high-order Raman pumps, and enhanced bidirectional ROPA with third-order Raman pumping in this experiment to optimize system performance. Two types of G.654E fibers are also fully characterized and used as span fibers. The improvement of transmission distance is mainly due to the remote pump power for RGU can be increased by nearly 4 dB in G.654E fiber by the third-order Raman pumping. At last, a single 800 Gb/s channel is transmitted over 447.96 km with a span loss of 73.16 dB. As far as we know, this is the longest 800 Gb/s unrepeatered transmission distance ever reported.

Risk Factors for Nonalcoholic Fatty Liver Disease among Patients Referred to Radiological Departments at Hail Hospitals, KSA

Background: Nonalcoholic fatty liver disease (NAFLD) incidence and prevalence have increased globally. The gravity of this chronic disease comes from its ability to progress to cirrhosis and hepatocellular carcinoma, which are rising rapidly. Genetic, demographic, environmental, and clinical factors are significant in the occurrence of NAFL. This study aimed to assess risk factors that affect the occurrence of NAFLD. Methods and Results: This cross-sectional study was carried out at hospitals in the Hail Region, KSA. It included 160 patients: 76 were considered as control (normal liver), and 84 suffered from fatty liver (according to a US image). Sonography was carried out using a US scanner with curvilinear transducers having a frequency of 3.5MHz. The following data were obtained: age, BMI, clinical history, including long-term medication of more than 3 months (oral antidiabetic medications, hormone replacement therapy for hyperthyroidism, and antihypertensive drug), T2D, viral hepatitis, liver span, lipidemia, metabolic disorders, and weight loss. The prevalence of NAFLD increases significantly among patients taking medications for a long time and T2D patients (P<0.001). Hepatomegaly is one of the most common physical examination findings of NAFLD (P<0.001). Conclusion: A periodic US examination is helpful because it can reveal fatty infiltration of the liver in the early stages to avoid fatal complications, especially for patients with long-term medication or T2D. Other studies with larger sample sizes and different known risk factors are needed to discover all risk factors for the KSA population.

A Study of Power Efficiency Maximization in Submarine Cable Systems

Power efficiency is a key concept in submarine cable transmission systems because of fixed and limited electrical power supplies. Electrical power is provided by a DC voltage applied across the cable from power feed equipment (PFE) located at the terminal ends and is used to power all optical amplifiers throughout the entire link which may be many thousands of kilometers. We examine here via system modeling aspects of power efficiency in the context of maximizing this quantity, primarily with respect to the optimal generalized signal-to-noise ratio (GSNR). We explore the dependence on capacity metric, span loss, link length, and fiber attenuation. We also compare the optimal GSNR predicted using pump power as a measure of power consumption in a single fiber with total cable capacity predicted by application of a pump sharing model and the resulting electrical-to-optical conversion efficiency predicted as a function of amplifier output power, span loss, and repeater power available. We find that the cable capacity measure predicts somewhat higher optimal GSNR than the single fiber measure based on amplifier pump power. The optimal GSNR decreases with longer link length and optimal span loss is somewhat higher than previous results based on different analyses.

High-speed multi-channel long-haul coherent optical transmission system

In this work, high-speed transmission over the long-haul optical channel using orthogonal frequency division multiplexing (OFDM) was investigated. Furthermore, we recommend mixing polarization division multiplexing (PDM) with coherent OFDM (CO-OFDM) and quadrature amplitude modulation (16-QAM) to improve spectral efficiency (SE) while transmitting over a wavelength division multiplexing (WDM) system. An 800 Gb/s WDM PDM-CO-OFDM-16QAM transmission system with various channel spacing of 100 GHz, 50 GHz, and 25 GHz is examined utilizing the OptiSystem (2021) version 18.0 software package over ten spans of 60 km standard single-mode fiber (SSMF). Different channel spacing WDM systems have been compared in terms of performance and SE. The results reveal that the WDM system with 100 GHz channel spacing has a longer transmission range and needs minimal optical signal to noise ratio (OSNR) at the reception. The 25 GHz channel spacing WDM system exceeds the others in terms of SE. Further, the effect of ultra-low loss and large effective area fiber in lowering span loss and nonlinear effects for 25 GHz channel spacing WDM system is investigated. The findings show that the system performance with the new fiber outperforms the SSMF. The acceptable bit error rate (BER) for this study is 0.033 (20% concatenated forward error correction (FEC) threshold).

On Sparse Gain Flattening in Pump-Constrained Submarine Links

Having in mind the capacity optimization of power-constrained submarine links, by following the work in (Cho <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">et al.</i> , 2020) we first compare the achievable information rate (AIR) of gain-flattened and un-flattened short links (called here blocks) of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$N_{b}\leq 12$</tex-math></inline-formula> spans with span loss 16.5 dB and with end-span single-stage co-pumped erbium-doped fiber amplifiers (EDFA) when the transmitted wavelength division multiplexed (WDM) channels all have the same transmitted power. All EDFAs have the same pump power and the same physical parameters. In the flattened case, each EDFA is followed by an ideal gain-flattening filter (GFF) that chops off the EDFA gain exceeding the span loss. No GFFs are used in the un-flattended case. We show that, for block length <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$N_{b}&gt;7$</tex-math></inline-formula> , at large-enough input power the AIR of the GFF block exceeds that of the no-GFF block, while for <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$N_{b}\leq 7$</tex-math></inline-formula> at large input power the AIR is about the same. We next build a long submarine link by concatenating many <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$N_{b}$</tex-math></inline-formula> -span no-GFF blocks, and placing a GFF at the last EDFA of each block in order to flatten the block gain down to the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$N_{b}$</tex-math></inline-formula> -span loss, and calculate the AIR of the resulting sparse-GFF submarine link, accounting also for nonlinear interference. For a 287-span case-study link with span loss 9.5 dB, we show that the best power efficiency is achieved by blocks of size <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$N_{b}=6$</tex-math></inline-formula> (i.e., one GFF every 6 spans) when the pump is around 11 mW. When the GFF excess loss is 0.3 dB the top-AIR gain over the standard all-GFF system is 9.5%, a value that decreases to 4% when the excess loss is zero. Considering that modern submarine-grade GFFs have almost zero excess loss, and that the most efficient pump power is likely too low to operate with, we conclude that sparse-GFF links offer little advantage in practice over the current design.

A novel preparation and vapor phase modification of 2D‐open channel bioadsorbent for uranium separation

AbstractAn economical and highly uranium extraction from seawater remains a crucial task for energy sources and environmental safety. Aiming for improving the mass transfer rate of uranium from seawater, a new synthetic strategy was adopted to synthesize two‐dimensional‐open channel microporous bioadsorbent for uranium extraction from seawater. Herein, a vapor phase modification approach was adopted to graft divinylbenzene (DVB), and polyacrylonitrile (AN) onto the surfaces of microporous frameworks via a free radical polymerization method. The postsynthetic functionalization was carried out by hydrothermal process, where amidoxime groups are structure‐directing agents to trap uranium. Furthermore, amidoxime groups not only enhanced hydrophilicity but also adjusts adsorbents pKa. AO‐Fc faces minimum interference of competing ions and achieves a high uranium adsorption capacity of 8.57 ± 0.02 and 409 ± 1 mg/g in seawater and simulated solution. Despite its stable structure, AO‐Fc exhibits a long life span and negligible weight loss revealed AO‐Fc could be applied as a potential adsorbent for radionuclides.

High-Generalizability Reinforcement Learning Based Capacity Optimization in WDM Long-Haul Networks

We propose a fast machine learning assisted capacity optimization in a point-to-point link of an elastic optical network using a reinforcement learning (RL) algorithm. We demonstrate a RL agent trained on idealized parameters in simulation, and compare the results with classical optimization algorithms such as a genetic algorithm and a simple power sweep. Furthermore, we present the high generalization ability of the RL agent under varying link conditions. Experimental results show that for 8 DWDM channels over nine 50km spans of True Wave Classic NZDSF with a span loss of 12 dB the RL agent is able to cope with these unseen conditions, removing the need to optimize for every possible link scenario during training.

Accuracy of analytical expressions for Rayleigh backscattered crosstalk in bidirectional multi-core fiber transmissions.

Use of bidirectional multi-core fiber (MCF) transmissions is attractive as it suppresses inter-core crosstalk by propagating the signals in opposite directions between nearest neighboring cores; therefore, signal quality and/or core density is improved compared with unidirectional transmissions where all the signals propagate in the same direction across the cores. In long-haul bidirectional MCF transmissions, Rayleigh backscattering is one of the major causes of inter-core crosstalk (XT). In this paper, we derive approximate expressions for Rayleigh backscattered XT and discuss the accuracy of the approximations. The derived expressions revealed that the reduction from conventional co-propagating XT to backscattered XT depends approximately only on wavelength, refractive index, effective area, the Rayleigh scattering component in propagation loss, and span loss.

A comparative analysis of matrix reordering algorithms regarding canonical data patterns

Matrix reordering is an Information Visualization topic that aims to study how to reveal information hidden within matrix-based visualizations, through appropriate reordering of its rows and columns. Considering the plethora of algorithms currently available to perform this task, and the set of matrix patterns presented in the visualization literature, we noted a lack of a comprehensive comparative analysis related to a subset of these patterns, known as canonical data patterns. Thus, this work aimed to perform a broad comparison of 37 state-of-the-art reordering algorithms by measuring the efficiency (execution time) and effectiveness (which combines objective functions as Moore Neighborhood, Minimal Span Loss Function and Circular Correlation, and a qualitative approach by visually assessing the output matrices) of the algorithms. We used as input a large synthetic matrix data set with different canonical data patterns. As a result, it was possible to indicate the most appropriate reordering algorithms for each pattern considered.

Independent and mixed transmission of 166.5 Gb/s PM‐8QAM and 222 Gb/s PM‐16QAM Nyquist‐wavelength division multiplexed superchannel for long‐haul metro network

SummaryThis paper investigates the Nyquist‐wavelength division multiplexed (Nyquist‐WDM) terabit superchannel by employing independent and mixed line rate (MLR) transmission of different polarization‐multiplexed quadrature amplitude modulation (PM‐QAM) subcarriers. Here, terabit superchannel transmission including forward error correction overhead is successfully achieved by employing either 7 × 166.5 Gb/s PM‐8QAM or 5 × 222 Gb/s PM‐16QAM or both 2 × 166.5 Gb/s PM‐8QAM and 3 × 222 Gb/s PM‐16QAM simultaneous transmission. Considering linear filtering penalties and nonlinear propagation effects, the proposed superchannel is transmitted over standard single‐mode fiber (SSMF) and pure silica core fiber (PSCF) along with erbium‐doped fiber amplifier (EDFA) at 19.8‐ and 15.12‐dB span loss for SSMF and PSCF, respectively. The performance of both terabit superchannels is analyzed in terms of maximum reach, good spectral efficiency, highest transmission capacity, and optimum launch power with variation in channel spacing from 50‐GHz fixed ITU‐T grid to 29 GHz, at an acceptable bit error rate (BER). To achieve BER 4 × 10−3, MLR‐based 166.5 Gb/s PM‐8QAM and 222 Gb/s PM‐16QAM suffer a penalty of 5.5‐ and 9.2‐dB OSNR over Nyquist‐only 7 × 166.5 Gb/s PM‐8QAM and 5 × 222 Gb/s PM‐16QAM transmission at the advent of a flexible multi‐flow transponder. It is observed that at 33.33‐GHz Nyquist spacing over PSCF, 5 × 222 Gb/s PM‐16QAM and 7 × 166.5 Gb/s PM‐8QAM superchannels deliver a reach up to 1800 and 2970 km, while MLR approach results in extreme reach of 2250 and 3600 km over PSCF as per MLR PM‐16QAM and PM‐8QAM subcarriers, respectively. Hence, an appreciable spectral efficiency–distance product (SEDP) is achieved due to PSCF at Nyquist spacing of 33.33 GHz with 5.25 bit/s/Hz spectral efficiency. A good link power budget is also calculated for the proposed MLR‐based Nyquist‐WDM superchannel. MLR‐based PM‐16QAM and PM‐8QAM subcarriers deliver excellent SEDP of 11,812 and 18,900 bit/s/Hz·km, respectively, which is, to the best of author's knowledge, better on comparing with the other existing literature for single‐core channel explorations.

Modulation format dependence on transmission reach in phase-sensitively amplified fiber links.

We quantify the maximum transmission reach for phase-insensitive amplifier (PIA) and phase-sensitive amplifier (PSA) links with different modulation formats and show that the maximum transmission reach increase (MTRI) when using PSAs compared to PIAs is enhanced for higher-order modulation formats. The higher-order modulation formats are more susceptible to smaller phase rotations from nonlinearities, and PSAs are efficient in mitigating these smaller phase distortions. Numerical simulations were performed for single- and multi-span PIA and PSA links with single and multiple wavelength channels. We obtain a significant enhancement in the MTRI with PSAs compared to PIAs when using higher-order modulation formats for both the single- and multi-channel systems in single- and multi-span links. We verify the enhancement with a single-span, single-channel system experiment. We also demonstrate, for the first time, a 64-QAM modulation format fiber transmission in phase-sensitively amplified link, with a 13.3-dB maximum allowable span loss increase compared to a phase-insensitively amplified link.

Joint channel power and amplifier gain optimization in coherent DWDM systems

In this paper, the channel power and amplifier gain of coherent dense wavelength division multiplexing (DWDM) fiber-optic communication systems are jointly optimized. The objective is to maximize the minimum margin of signal to noise ratio (SNR). The presented optimization problem is non-linear and non-convex, in which the intra- and inter-channel nonlinear interference (NLI) noise of fiber is estimated by using the so-called Gaussian noise (GN) model. Furthermore, the noise and other practical aspects of optical amplifiers such as output power saturation, maximum gain limitation, gain tilt and ripple, and noise figure non-flatness are modeled. Finally, we show that this problem can be reformulated as a convex optimization. Our results reveal that joint power and amplifier gain optimization in a 5-span fiber link with span length of 80 km (100 km) leads to 1 dB (0.47 dB) higher SNR than the conventional power optimization method in which amplifier gain is fixed and equals to span loss. By considering gain ripple and tilt in a 8-span fiber link with span length of 80 km, we observed that our algorithm has 0.72 dB and 1.86 dB higher SNR than the alternative power optimization methods in which amplifier gain is equalized and unequalized, respectively.

Trends in Optical Span Loss Detected Using the Time Series Decomposition Method

Optical fiber cables deployed in the last 30 years have been considered to be long-lived components due to the generally high level of reliability of glass and the robustness of cable construction. Like all other components however, optical cables can change with age as a result of their construction or deployment characteristics as well as operational and environmental stress factors. In this article, we apply a time-series decomposition method on span loss data collected during 12 months in four bidirectional spans of a production network in order to detect long-term degradation of the fiber plant. After extracting the trend component, a Mann–Kendall test is applied to the span loss curves and a Sen's slope estimator test is used for determining the magnitude of span loss change. The method allows detecting a 1.3% increase in span loss over the 12-month period of observation in one of the fiber spans. This trend is confirmed using a linear regression model computed according to Theil Sen method applied to additional one-year data. The proposed method can allow the early detection of fiber plant degradation and the proactive planning of fiber replacement.

Unrepeatered 240-km 64-QAM Transmission Using Distributed Raman Amplification over SMF Fiber

We present a theoretical and experimental investigation of unrepeatered transmission over standard single-mode fiber (SMF-28) using several schemes of distributed Raman amplification, including first, second, and dual order. In order to further extend the transmission distance, we utilize advanced bidirectional higher-order ultra-long Raman fiber laser-based amplification, where we use fiber Bragg gratings (FBGs) to reflect Stokes-shifted light from the secondary pumps. Our work demonstrates the possibility of transmission up to 240-km span length with a total span loss of 52.7 dB. Here, we use a 28-Gbaud signal using a 64-quadrature amplitude modulation (QAM) modulation format. Our results highlight the contribution of nonlinear compensation using digital back propagation in a digital signal processor (DSP) code at the receiver.

Cross-Phase Modulation Mitigation in Phase-Sensitive Amplifier Links

We experimentally investigate a wavelength-division multiplexing (WDM) system with a single span of 80 km standard single-mode fiber (SSMF) and a phase-sensitive amplifier (PSA) as a pre-amplifier. Using two channels spaced 25 GHz apart with single-polarization 10-Gbaud quadrature phase-shift keying (QPSK) signal, we show quantitatively that a PSA can mitigate self-phase modulation (SPM) and cross-phase modulation (XPM). With three single-polarization 10-Gbaud QPSK channels spaced 12.5 GHz apart, we verify that PSA can mitigate XPM and also determine an allowed span loss increase of 9.5 dB for the center channel with correlated edge channels for the PSA compared to the phase-insensitive amplifier (PIA) due to the combined improvement from low-noise amplification and nonlinearity mitigation.

Unrepeatered Transmission Over 670.64 km of 50G BPSK, 653.35 km of 100G PS-QPSK, 601.93 km of 200G 8QAM, and 502.13 km of 400G 64QAM

We report the results of 50G, 100G, 200G, 400G un- repeatered transmission aimed at achieving the longest distance without any inline active elements, this system realizes record single-carrier 50 Gb/s (PM-BPSK), 100 Gb/s (PS-QPSK), 200 Gb/s (PM-8QAM) and 400 Gb/s (PM-64QAM) unrepeatered transmission over 670.64 km with 103.95 dB span loss, 653.35 km with 101.27 dB span loss, 601.93 km with 93.3 dB span loss, and 502.13 km with 77.83 dB span loss, respectively. This is achieved using optimized high-order Raman pumps, cascaded RGUs and coherent modulation format with concatenated FEC. G.654.E fiber with ultra-low loss & 130 μm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> effective area is used as span fiber.

Hiroshima/Nagasaki survivors and their offspring: results of longterm epidemiological studies

After the atomic bombing of Hiroshima and Nagasaki, long-term epidemiological studies were undertaken on the irradiated survivors and their offspring, and are still underway. These thorough studies involving tens of thousands of persons and published in hundreds of papers have shown a moderate increase in cancer incidence for irradiated survivors, with limited impact on their life span (loss of one year at most). In studies on the offspring of these survivors, no statistically significant deleterious effect on malformation frequency, incidence of mutations or mortality from cancer and other diseases has been seen so far. These data are actually the basis for current radiation safety levels; they show that health risks from radiation are limited, but they are not applicable to complex situations such as nuclear power station accidents that involve diverse types of radiation as well as contamination by radioactive materials.

Diabetes with early kidney involvement may shorten life expectancy by 16 years

This study aimed to identify the excess risks associated with diabetic patients with early kidney involvement (early diabetic kidney disease). The mortality risks of early diabetic kidney disease, defined as diabetes in early stages 1-3 chronic kidney disease (CKD), were assessed from a cohort of 512,700 adults in Taiwan participating in a health surveillance program from 1994-2008. Three related groups were identified and compared: diabetes without CKD, early diabetic kidney disease, and early CKD without diabetes. Deaths were ascertained through the National Death Registry. One-third of diabetics had early kidney disease, and approximately two-thirds of patients were classified with early CKD due to proteinuria. Patients with early diabetic kidney disease had more lifestyle risks such as inactivity or obesity, which characteristically amplified excess mortality by up to five times. The three-fold increase in all-cause mortality (hazard ratio 3.16) and a 16-year loss in life expectancy made early diabetic kidney disease a serious and yet often overlooked disease, with most patients unaware of their kidney involvement. Mortality for early diabetic kidney disease was nearly twice as high as that for early CKD (hazard ratio 2.01) or diabetes without CKD (hazard ratio 1.79). The 16-year life span loss is much worse than individually from early CKD (six years) or diabetes (ten years). Thus, identifying early proteinuria among diabetic patients and realizing the importance of reducing lifestyle risks like inactivity is a clinical challenge, but can save lives.