A comparison of the radiation vulnerabilities of ring resonator andinterferometric fiber optic gyroscopes

A comparison is made between passive ring-resonator and interferometric fiber-optic gyroscope sensitivity to the radiation darkening of optical fibers. The radiation degradation factor for each type of gyroscope is developed, and figures of merit are given for comparing gyroscopes independently of the specific mechanization or modulation scheme used. It is shown that for most practical situations, interferometric gyros offer superior performance in radiation environments     

Polarization Mode Dispersion of Installed Fibers

Polarization mode dispersion (PMD), a potentially limiting impairment in high-speed long-distance fiber-optic communication systems, refers to the distortion of propagating optical pulses due to random birefringences in an optical system. Because these perturbations (which can be introduced through manufacturing imperfections, cabling stresses, installation procedures, and environmental sensitivities of fiber and other in-line components) are unknowable and continually changing, PMD is unique among optical impairments. This makes PMD both a fascinating research subject and potentially one of the most challenging technical obstacles for future optoelectronic transmission. Mitigation and compensation techniques, proper emulation, and accurate prediction of PMD-induced outage probabilities critically depend on the understanding and modeling of the statistics of PMD in installed links. Using extensive data on buried fibers used in long-haul high-speed links, the authors discuss the proposition that most of the temporal PMD changes that are observed in installed routes arise primarily from a relatively small number of "hot spots" along the route that are exposed to the ambient environment, whereas the buried shielded sections remain largely stable for month-long time periods. It follows that the temporal variations of the differential group delay for any given channel constitute a distinct statistical distribution with its own channel-specific mean value. The impact of these observations on outage statistics is analyzed, and the implications for future optoelectronic fiber-based transmission are discussed     

Experience with a Hybrid Processor: K-Means Clustering

We discuss hardware/software co-processing on a hybrid processor for a compute- and data-intensive multispectral imaging algorithm, k-means clustering. The experiments are performed on two models of the Altera Excalibur board, the first using the soft IP core 32-bit NIOS 1.1 RISC processor, and the second with the hard IP core ARM processor. In our experiments, we compare performance of the sequential k-means algorithm with three different accelerated versions. We consider granularity and synchronization issues when mapping an algorithm to a hybrid processor. Our results show that speedup of 11.8X is achieved by migrating computation to the Excalibur ARM hardware/software as compared to software only on a Gigahertz Pentium III. Speedup on the Excalibur NIOS is limited by the communication cost of transferring data from external memory through the processor to the customized circuits. This limitation is overcome on the Excalibur ARM, in which dual-port memories, accessible to both the processor and configurable logic, have the biggest performance impact of all the techniques studied.     

Tumor-Stroma Ratio and Programmed Cell Death Ligand 1 Expression in Preoperative Biopsy and Matched Laryngeal Carcinoma Surgical Specimen

Programmed cell death ligand 1 (PD-L1) seems to rely on close relations between neoplastic and immune cells in the tumor microenvironment. Tumor to stroma ratio (TSR) has been associated with prognosis in different malignancies. The aims of this exploratory investigation were to analyze for the first time the: (i) association between TSR, PD-L1 expression and other clinical–pathological features in laryngeal squamous cell carcinoma (LSCC) biopsies and paired surgical specimens; (ii) prognostic and predictive role of TSR and PD-L1. TSR, PD-L1 expression (in terms of combined positive score [CPS]), and other clinical–pathological features were analyzed in biopsies and surgical specimens of 43 consecutive LSCC cases. A CPS < 1 evaluated on surgical specimens was associated with a low TSR (stroma rich) on both biopsies and surgical specimens (p = 0.0143 and p = 0.0063). Low TSR showed a significant negative prognostic value when evaluated on both biopsies and surgical specimens (HR = 8.808, p = 0.0003 and HR = 11.207, p = 0.0002). CPS ≥ 1 appeared to be a favorable prognostic factor (HR = 0.100, p = 0.0265). The association between bioptic and surgical specimen TSR and PD-L1 expression should be further investigated for a potential impact on targeted treatments, also with regard to immunotherapeutic protocols.     

The genetic relationship of body weight and early-lactation health disorders in two experimental herds

The objectives of this study were to estimate genetic parameters for body weight (BW) and BW change (BWC) and genetic correlations of BW and BWC with diseases and genomic predicted transmitting abilities (PTA) of productive and conformation traits of Holsteins during the first 120 DIM. Daily BW data were from the Afiweigh cow body weighing system (SAE Afikim, Kibbutz Afikim, Israel), which records BW as a cow exits the milking parlor. Disease categories included metabolic diseases, ketosis, infectious diseases, mastitis, reproductive diseases, and other diseases. Edited data included 68,914 and 11,615 daily BW observations from 441 Pennsylvania State University and 72 Virginia Tech Holstein cows, respectively. Two-trait random regression models were used to estimate relationships between BW, BWC, and diseases at 25, 38, and 58 mo of age at calving. Fixed effects for BW were age at calving nested within lactation group, week of lactation, and herd date; random effects for BW included animal, permanent environment, and error. Fixed effects for disease were herd-year-season of calving and age at calving nested within lactation group; random effects for disease were animal, permanent environment (for mastitis only), and error. Correlations of PTA for BW and BWC with genomic PTA for productive and type traits were also estimated with data from 117 cows. Heritability estimates for daily BW ranged from 0.34 to 0.63. Greater BW and less BWC were favorably correlated with ketosis, metabolic diseases, infectious diseases, and other diseases. The genetic correlation estimate between BW and ketosis was strongest at 60 DIM (−0.51), and genetic correlation estimates at 60 DIM with metabolic diseases (−0.52), infectious diseases (−0.81), and other diseases (−0.48) followed the same trend as ketosis. The genetic correlation estimate between BWC and ketosis was strongest for the change from 5 to 20 DIM (0.70) and was similar for metabolic diseases (0.37), infectious diseases (0.74), and other diseases (0.49). Correlations of BW and BWC with reproductive diseases tended to be in the reverse direction of those reported for ketosis. A larger PTA for BW was significantly correlated with smaller genomic PTA for milk yield, dairy form, rear udder height, and udder cleft. Predicted transmitting ability for BWC was negatively correlated with genomic PTA for protein percentage, strength, and hip width (ranging from −0.26 to −0.13 across lactation) and was positively correlated with dairy form, rear udder height, and udder cleft (ranging from 0.20 to 0.37 across lactation). Selection for reduced BW loss can be implemented with automated body weighing systems and may be successful in decreasing disease incidence in the early stages of lactation.     

Muscular effort and musculo-skeletal disorders in piano students: electromyographic, clinical and preventive aspects

An investigation was made on the relationship between music practice and musculo-skeletal disorders among piano students, with the main aim of developing health education programmes that would improve the performance and health of the students. The investigation covered three areas: (a) Analysis of study organization and main musculo-skeletal complaints achieved by a questionnaire distributed to all piano students at the Milan Conservatory. (b) Vocational electromyographic analysis of the effort exerted by the various muscle groups of the trunk, of the shoulder and shoulder blade girdle, and of the arm during performance of a standard set of piano exercises, an unseen passage and a passage of maximum difficulty. This analysis was made on a sample of six subjects. (c) A series of preventive measures was developed on the basis of a critical assessment of the results (38% of the students practised for excessively long periods without breaks; 62% had from 1 to 5 complaints, the most affected sites being the spine and the trapezius muscles). These consisted largely of a health education programme aimed at helping the students to suitably organize practice and rest periods and in instructing them in appropriate exercises for relaxation and stretching of overused muscle groups and strengthening the supporting muscle groups. Changes in lifestyle were also suggested.     

High-capacity packet-switched optical ring network

We propose a novel architecture with MAC and admission control protocols for a high-capacity packet-switched optical ring network. In this network the link capacity significantly exceeds the node bit rate. Nodes transmit and receive packets on multiple wavelengths in parallel by using novel optical techniques. Network control is simple since the load is balanced over wavelengths at the physical layer. The MAC protocol is based on credits, and the derived admission control protocol has similar complexity as in a single channel network. Consequently, the network can follow fast traffic changes which are typical in data networks     

Peripheral benzodiazepine receptor expression on leukocytes and neutrophil function during anticonvulsant monotherapy

AIM: To gain a full understanding of the concept of equity and means of promoting and monitoring a more equitable healthservice. BACKGROUND: With previous policy decisions having sidelined equity, a new government is likely to wish to reverse this trend. ORIGINS OF INFORMATION: Government and expert opinion. DATA ANALYSIS: A critical approach to previous literature. KEY ISSUES: Equity is not a unitary concept and so it is explored and dissected using the framework of: Distribution of Resources, Access and Uptake of Healthcare, Standards and Outcomes of Healthcare, Health Status. Means of improving and monitoring equity in these four areas are suggested. CONCLUSIONS: There are a number of ways of considering the concept of equity and for any fruitful discussion to occur there needs to be an agreed working definition. Specific topics are discussed where equity is lacking and a plan of action is suggested which is likely to improve equity in the areas identified.     

Clipping distortion in lightwave CATV systems: models, simulations,and measurements

Theoretical, numerical, and experimental investigations of clipping distortions in CATV systems are reported. The applicability of A.A.M. Saleh's (1989) calculation of the carrier-to-nonlinear-distortion ratio (CNLD) is extended by incorporating a more precise spectral analysis and further analytic results. An effective transfer function model which spectrally resolves the clipping distortion at intermodulation products (IMPs) of all orders and frequencies, and features closed-form analytic calculation of the second- and third-order distortions (CSO and CTB) from basic principles, as well as the CNLD, is introduced. It is found that Saleh's model slightly overestimates the simulation results for the CNLD, while the new model is in essential agreement with the simulation for all three distortion measures. Experimental measurements of the CSO, CTB, and CNLD over a 50-dB range in distortion exhibited excellent agreement with the simulations and the new model over the entire range. The unified nature of the model allows standard CATV, CSO, and CTB measurements to be theoretically connected to the CNLD and clipping boundary