Blind Equalization in Optical Communications Using Independent Component Analysis

We propose a multi-tap independent component analysis (ICA) scheme for blind equalization and phase recovery in coherent optical communication systems. The proposed algorithm is described and evaluated in the cases of QPSK and 16-QAM transmission. Comparison with CMA equalization shows similar performance in the case of QPSK and an advantage for the ICA equalizer in the case of 16-QAM. The equalization scheme was evaluated in a multi-span optical communications system impaired by both polarization mode dispersion (PMD) and polarization dependent loss (PDL)

Commercially Available Antibodies to Human Tumour Necrosis Factor-α Tested for Cross-Reactivity with Ovine and Bovine Tumour Necrosis Factor-α using Flow Cytometric Assays

A thorough understanding of the immune system, including the role of different cytokines, during inflammatory diseases in ruminants could lead to the development of new diagnostic methods and treatments. Tumour necrosis factor-α (TNF-α) is an important cytokine in the onset of the inflammatory responses. Unfortunately, the number of studies on cytokines, like TNF-α, in ruminants is limited due to a lack of species-specific reagents. As cytokines have remained rather conserved during evolution, cross-reactivity between animal species may occur. Therefore, the aim of the present study was to investigate 5 commercially available antibodies against human TNF-α for their ability to cross-react with ovine and/or bovine TNF-α, using a bead-based flow cytometric method. Two of the antibody clones (Mab 11 and 6401.1111) showed cross reactivity with ovine recombinant TNF-α in concentrations above 2.5 ng/ml. However, none of the antibodies detected TNF-α in bovine milk, or serum containing known concentrations of bovine TNF-α, as earlier determined with ELISA. The results could be due to inability of the antibodies to cross-react between species, but quenching of the signal by matrix proteins might also have lowered the response

Changes in some Blood Micronutrients, Leukocytes and Neutrophil Expression of Adhesion Molecules in Periparturient Dairy Cows

Dairy cows are highly susceptible to infectious diseases, like mastitis, during the period around calving. Although factors contributing to increased susceptibility to infection have not been fully elucidated, impaired neutrophil recruitment to the site of infection and changes in the concentrations of some micronutrients related with the function of the immune defence has been implicated. Most of the current information is based on studies outside the Nordic countries where the conditions for dairy cows are different. Therefore, the aim of the study was to evaluate changes in blood concentrations of the vitamins A and E, the minerals calcium (Ca), phosphorous (P), and magnesium (Mg), the electrolytes potassium (K) and sodium (Na) and the trace elements selenium (Se), copper (Cu) and zinc (Zn), as well as changes in total and differential white blood cell counts (WBC) and expression of the adhesion molecules CD62L and CD18 on blood neutrophils in Swedish dairy cows during the period around calving. Blood samples were taken from 10 cows one month before expected calving, at calving and one month after calving. The results were mainly in line with reports from other countries. The concentrations of vitamins A and E, and of Zn, Ca and P decreased significantly at calving, while Se, Cu, and Na increased. Leukocytosis was detected at calving, mainly explained by neutrophilia, but also by monocytosis. The numbers of lymphocytes tended to decrease at the same time. The mean fluorescent intensity (MFI) of CD62L and CD18 molecules on blood neutrophils remained constant over time. The proportion of CD62L+ neutrophils decreased significantly at calving. The animals were fed according to, or above, their requirements. Therefore, changes in blood levels of vitamins, minerals and trace elements were mainly in response to colostrum formation, changes in dry matter intake, and ruminal metabolism around calving. Decreased levels of vitamins A and E, and of Zn at calving might have negative implications for the functions of the immune defence. The lower proportion of CD62L+ neutrophils at calving may result in less migration of blood neutrophils into the tissues, and might contribute to the increased susceptibility to infections at this time

3D Orientation Estimation with Multiple 5G mmWave Base Stations

We consider the problem of estimating the 3D orientation of a user, using the downlink mmWave signals received from multiple base stations. We show that the received signals from several base stations, having known positions, can be used to estimate the unknown orientation of the user. We formulate the estimation problem as a maximum likelihood estimation problem in the the manifold of rotation matrices. In order to provide an initial estimate to solve the non-linear non-convex optimization problem, we resort to a least squares estimation problem that exploits the underlying geometry. Our numerical results show that the problem of orientation estimation can be solved when the signals from at least two base stations are received. We also provide the orientation lower error bound, showing a narrow gap between the performance of the proposed estimators and the bound

Backward particle message passing

Particle methods are an established way to represent messages and perform message passing in factor graphs. Despite their common use, there are several cases for which messages are hard to compute, even in linear models. Building on results from Gaussian message passing, we demonstrate how backward particle-based messages can be computed and describe a practical application in the context of fiber-optical communications

A residual performance methodology to evaluate multifunctional systems

The development of multifunctional materials and structures is receiving increasing interest for many applications and industries; it is a promising way to increase system-wide efficiency and improve the ability to meet environmental targets. However, quantifying the advantages of a multifunctional solution over monofunctional systems can be challenging. One approach is to calculate a reduction in mass, volume or other penalty function. Another approach is to use a multifunctional efficiency metric. However, either approach can lead to results that are unfamiliar or difficult to interpret and implement for an audience without a multifunctional materials or structures background. Instead, we introduce a comparative metric for multifunctional materials that correlates with familiar design parameters for monofunctional materials. This metric allows the potential benefits of the multifunctional system to be understood easily without needing a holistic viewpoint. The analysis is applied to two different examples of multifunctional systems; a structural battery and a structural supercapacitor, demonstrating the methodology and its potential for state-of-the-art structural power materials to offer a weight saving over conventional systems. This metric offers a new way to communicate research on structural power which could help identify and prioritise future research

Stallion Sperm Viability, as Measured by the Nucleocounter SP-100, Is Affected by Extender and Enhanced by Single Layer Centrifugation

On-stud assessment of stallion sperm quality can be problematic. A new instrument, the Nucleocounter SP-100, was validated for measuring stallion sperm concentration and viability. It was subsequently used to evaluate sperm viability in Kenney's extender and INRA96. There was a strong correlation between sperm concentrations measured by the Nucleocounter SP-100 and by the Bürker counting chamber (r = 0.84; P < .001). Similarly, there was a good correlation between sperm viability results from the Nucleocounter SP-100 and flow cytometric results (r = 0.73; P < .001). Sperm viability at 24 hours was significantly better for samples extended in INRA96 than in Kenney's extender (P < .001). Furthermore, sperm kinematics were better for stored samples in INRA96 than in Kenney's extender. Single Layer Centrifugation selected spermatozoa that maintained their viability better during storage for 24 hours than the uncentrifuged samples. In conclusion, the type of semen extender used and Single Layer Centrifugation were found to influence both the kinematics and viability of stallion spermatozoa. The Nucelocounter-SP100 was considered to be a useful instrument for rapidly measuring stallion sperm concentration and viability

Nonlocal effects in high energy charged particle beams

Within the framework of the thermal wave model, an investigation is made of the longitudinal dynamics of high energy charged particle beams. The model includes the self-consistent interaction between the beam and its surroundings in terms of a nonlinear coupling impedance, and when resistive as well as reactive parts are included, the evolution equation becomes a generalised nonlinear Schroedinger equation including a nonlocal nonlinear term. The consequences of the resistive part on the propagation of particle bunches are examined using analytical as well as numerical methods.Comment: 6 pages, 6 figures, uses RevTeX

40-Gbaud 16-QAM transmitter using tandem IQ modulators with binary driving electronic signals

We propose a novel 16-quadrature amplitude modulation (QAM) transmitter based on two cascaded IQ modulators driven by four separate binary electrical signals. The proposed 16-QAM transmitter features scalable configuration and stable performance with simple bias-control. Generation of 16-QAM signals at 40 Gbaud is experimentally demonstrated for the first time and visualized with a high speed constellation analyzer. The proposed modulator is also compared to two other schemes. We investigate the modulator bandwidth requirements and tolerance to accumulated chromatic dispersion through numerical simulations, and the minimum theoretical insertion attenuation is calculated analytically