Performance comparison of parallel optical interconnects for enterprise servers
There is an emerging need in the computing industry for higher bandwidth, longer distance, and increased density interconnections within clusters of high performance enterprise-class computer systems. Many of these servers share a common set of high level requirements which lend themselves to the use of parallel optical interconnects to either supplement or replace existing copper data buses. In this paper, we describe the results of application testing performed on 12-fiber parallel optical cables and connectors, including a relative comparison between three different multimode cable assembly sources. Assembly loss and effects of both axial and off-axis pull forces are measured for cable samples mated to a laser transmitter array. Significant variations exist in the performance of the same type of cable assembly from different manufacturing sources, particularly concerning their susceptibility to pull forces; we also investigate the effects of fiber strain relief to improve performance of these links. While currently available 12-fiber array connectors are not equivalent in performance to standard duplex connectors, this work suggests areas for future improvement and data communication application requirements which should be considered when using parallel fiber optic arrays.
Fiber Optic Data Communication Technological Trends And Advances
Contributors Preface Pt. 1 Technology Advances Ch. 1 History of Fiber Optics Ch. 2 Market Analysis and Business Planning Ch. 3 Small Form Factor Fiber Optic Connector Ch. 4 Specialty Fiber Optic Cables Ch. 5 Optical Wavelength Division Multiplexing for Data Communication Networks Ch. 6 Optical Backplanes, Board and Chip Interconnects Ch. 7 Parallel Computer Architectures Using Fiber Optics Pt. 2 The Future Ch. 8 Packaging Assembly Techniques Ch. 9 InfiniBand - The Interconnect from Backplane to Fiber Ch. 10 New Devices for Optoelectronics: Smart Pixels Ch. 11 Emerging Technology for Fiber Optic Data Communication Ch. 12 Manufacturing Challenges App. A Measurement Conversion Tables App. B Physical Constants App. C Index of Professional Organizations App. D OSI Model App. E Network Standards and Documents App. F Data Network Rates App. G Other Datacom Developments Acronyms Glossary Index
Familial Cortical Myoclonic Tremor and Epilepsy, an Enigmatic Disorder: From Phenotypes to Pathophysiology and Genetics. A Systematic Review
Background Autosomal dominant familial cortical myoclonic tremor and epilepsy (FCMTE) is characterized by distal tremulous myoclonus, generalized seizures, and signs of cortical reflex myoclonus. FCMTE has been described in over 100 pedigrees worldwide, under several different names and acronyms. Pathological changes have been located in the cerebellum. This systematic review discusses the clinical spectrum, treatment, pathophysiology, and genetic findings. Methods We carried out a PubMed search, using a combination of the following search terms: cortical tremor, myoclonus, epilepsy, benign course, adult onset, familial, and autosomal dominant; this resulted in a total of 77 studies (761 patients; 126 pedigrees) fulfilling the inclusion and exclusion criteria. Results Phenotypic differences across pedigrees exist, possibly related to underlying genetic differences. A “benign” phenotype has been described in several Japanese families and pedigrees linked to 8q (FCMTE1). French patients (5p linkage; FCMTE3) exhibit more severe progression, and in Japanese/Chinese pedigrees (with unknown linkage) anticipation has been suggested. Preferred treatment is with valproate (mind teratogenicity), levetiracetam, and/or clonazepam. Several genes have been identified, which differ in potential pathogenicity. Discussion Based on the core features (above), the syndrome can be considered a distinct clinical entity. Clinical features may also include proximal myoclonus and mild progression with aging. Valproate or levetiracetam, with or without clonazepam, reduces symptoms. FCMTE is a heterogeneous disorder, and likely to include a variety of different conditions with mutations of different genes. Distinct phenotypic traits might reflect different genetic mutations. Genes involved in Purkinje cell outgrowth or those encoding for ion channels or neurotransmitters seem good candidate genes.