Graphene Synthesis by Plasma-Enhanced CVD Growth with Ethanol

A modified route to synthesize graphene flakes is proposed using the Chemical Vapor Deposition (CVD) technique, by using copper substrates as supports. The carbon source used was ethanol, the synthesis temperature was 950°C and the pressure was controlled along the whole process. In this CVD synthesis process the incorporation of the carbon source was produced at low pressure and 950°C inducing the appearance of a plasma blue flash inside the quartz tube. Apparently, the presence of this plasma blue flash is required for obtaining graphene flakes. The synthesized graphene was characterized by different techniques, showing the presence of non-oxidized graphene with high purityThis work was supported by the Spanish Education and Research Ministry (MEC) under Grant MAT2010- 19804 and from Ministerio de Economía y Competitividad (MINECO) of Spain, through the grant ENE2014-57977-C2-1-R. Financial support from the U.S. Department of Energy, through the Massie Chair Project at Turabo University and from the U.S. Department of Defense under Grant W911NF-14-1- 0046, are also acknowledge

Fault Diagnosis for Complex Systems Using Coloured Petri Nets

Non

The Impact of Suicide Bereavement on Educational and Occupational Functioning: A Qualitative Study of 460 Bereaved Adults.

People bereaved by suicide are at an increased risk of suicide and of dropping out of education or work. Explanations for these associations are unclear, and more research is needed to understand how improving support in educational or work settings for people bereaved by suicide might contribute to reducing suicide risk. Our objective was to explore the impact of suicide on occupational functioning. We conducted a cross-sectional online study of bereaved adults aged 18-40, recruited from staff and students of British higher educational institutions in 2010. We used thematic analysis to analyse free text responses to two questions probing the impact of suicide bereavement on work and education. Our analysis of responses from 460 adults bereaved by suicide identified three main themes: (i) specific aspects of grief that impacted on work performance, cognitive and emotional domains, and social confidence; (ii) structural challenges in work or educational settings including a lack of institutional support, the impact of taking time off, and changes to caring roles; and (iii) new perspectives on the role of work, including determination to achieve. Institutional support should be tailored to take account of the difficulties and experiences described

Localization and Fingerprint of Radio Signals Employing a Multichannel Photonic Analog-to-Digital Converter

[EN] The fingerprint and localization of radio signals employing a multichannel photonic analog-to-digital converter (ADC) is proposed, analyzed, and demonstrated in a laboratory experiment. The photonic ADC detects the radio signals with high sensitivity in a large bandwidth without down-conversion stages. This is of special interest when processing emerging low-power wireless standards like ultra-wideband (UWB) radio. The optical processing in the multichannel photonic ADC is tailored for the localization and fingerprint of generic radio transmitters when orthogonal-frequency division multiplexing (OFDM) modulation is employed in the transmission. The photonic ADC includes engineered optical and electrical amplification. The experimental work demonstrates that detection of radio signals with -65 dBm power with signal-to-noise ratio better than 20 dB is feasible, which is in good accordance with the theoretical analysis. The multichannel photonic ADC comprises five optical channels which are precisely time-aligned in optical domain achieving 0.23-m spatial resolution (median) in the localization of radio transmitters. The experimental work also demonstrates that photonic-ADC processing is adequate for OFDM-based UWB radio-signal fingerprint including estimation of the average power, frequency band of operation, and time-frequency hopping pattern if applicable. UWB transmitter localization has been experimentally demonstrated with 0.4-m error.This work was supported in part by the European 7th Framework Program Project UCELLS FP7-IST-216785. The work of M. Morant was supported by Spain FPU MEC under Grant AP2007-01413.Llorente, R.; Morant, M.; Puche, JF.; Romme, J.; Amiot, N.; Uguen, B.; Duplicy, J. (2010). Localization and Fingerprint of Radio Signals Employing a Multichannel Photonic Analog-to-Digital Converter. IEEE Transactions on Microwave Theory and Techniques. 58(11):3304-3311. https://doi.org/10.1109/TMTT.2010.2076730S33043311581

Support Needs and Experiences of People Bereaved by Suicide: Qualitative Findings from a Cross-Sectional British Study of Bereaved Young Adults.

People bereaved by suicide are at increased risk of suicide, but evidence is lacking that available interventions reduce suicide risk. Few large-scale studies have described the views of suicide-bereaved people regarding their needs for support. Our objective was to explore the nature of young adults' experiences of support after bereavement by suicide and their views on valued and unhelpful aspects. We conducted a cross-sectional study of staff and students aged 18-40 at 37 United Kingdom (UK) higher educational institutions in 2010, eliciting qualitative responses to two questions probing experiences of support and unmet needs after the suicide of a close contact. We conducted thematic analysis of responses from 420 adults bereaved by suicide, of whom 75% had received support after the loss. We identified three broad descriptive areas corresponding to important aspects of support: value and experiences of the support received; views on specific support needs; and reasons for not seeking support. We found that needs for emotional support exist throughout the social networks of people who die by suicide but are often hidden. Our findings suggest a need for proactive offers of support from family, friends, and professionals after suicide, repeated regularly in case a bereaved person does not feel ready for support early on

Birefringence effects in multi-core fiber: coupled local-mode theory

© 2016 Optical Society of America. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modifications of the content of this paper are prohibitedIn this paper, we evaluate experimentally and model theoretically the intra- and inter-core crosstalk between the polarized core modes in single-mode multi-core fiber media including temporal and longitudinal birefringent effects. Specifically, extensive experimental results on a four-core fiber indicate that the temporal fluctuation of fiber birefringence modifies the intra- and inter-core crosstalk behavior in both linear and nonlinear optical power regimes. To gain theoretical insight into the experimental results, we introduce an accurate multi-core fiber model based on local modes and perturbation theory, which is derived from the Maxwell equations including both longitudinal and temporal birefringent effects. Numerical calculations based on the developed theory are found to be in good agreement with the experimental data.This work has been partly funded by Spain National Plan project MINECO/FEDER UE XCORE TEC2015-70858-C2-1-R; HIDRASENSE RTC-2014-2232-3; European Regional Development Fund (ERDF) and the Galician Regional Government under project GRC2015/018. A. Macho and M. Morant work was supported by BES-2013-062952 F.P.I. Grant and postdoc UPV PAID-10-14 program, respectively.Macho-Ortiz, A.; García Meca, C.; Fraile-Peláez, FJ.; Morant Pérez, M.; Llorente Sáez, R. (2016). Birefringence effects in multi-core fiber: coupled local-mode theory. Optics Express. 24(19):21415-21434. https://doi.org/10.1364/OE.24.021415S21415214342419Mizuno, T., Takara, H., Sano, A., & Miyamoto, Y. (2016). Dense Space-Division Multiplexed Transmission Systems Using Multi-Core and Multi-Mode Fiber. Journal of Lightwave Technology, 34(2), 582-592. doi:10.1109/jlt.2015.2482901Morant, M., Macho, A., & Llorente, R. (2016). On the Suitability of Multicore Fiber for LTE–Advanced MIMO Optical Fronthaul Systems. Journal of Lightwave Technology, 34(2), 676-682. doi:10.1109/jlt.2015.2507137Hayashi, T., Sasaki, T., Sasaoka, E., Saitoh, K., & Koshiba, M. (2013). Physical interpretation of intercore crosstalk in multicore fiber: effects of macrobend, structure fluctuation, and microbend. Optics Express, 21(5), 5401. doi:10.1364/oe.21.005401Fini, J. M., Zhu, B., Taunay, T. F., Yan, M. F., & Abedin, K. S. (2012). Statistical Models of Multicore Fiber Crosstalk Including Time Delays. Journal of Lightwave Technology, 30(12), 2003-2010. doi:10.1109/jlt.2012.2188017Luis, R. S., Puttnam, B. J., Cartaxo, A. V. T., Klaus, W., Mendinueta, J. M. D., Awaji, Y., … Sasaki, T. (2016). Time and Modulation Frequency Dependence of Crosstalk in Homogeneous Multi-Core Fibers. Journal of Lightwave Technology, 34(2), 441-447. doi:10.1109/jlt.2015.2474128Hayashi, T., Taru, T., Shimakawa, O., Sasaki, T., & Sasaoka, E. (2012). Characterization of Crosstalk in Ultra-Low-Crosstalk Multi-Core Fiber. Journal of Lightwave Technology, 30(4), 583-589. doi:10.1109/jlt.2011.2177810Fini, J. M., Zhu, B., Taunay, T. F., & Yan, M. F. (2010). Statistics of crosstalk in bent multicore fibers. Optics Express, 18(14), 15122. doi:10.1364/oe.18.015122Koshiba, M., Saitoh, K., Takenaga, K., & Matsuo, S. (2011). Multi-core fiber design and analysis: coupled-mode theory and coupled-power theory. Optics Express, 19(26), B102. doi:10.1364/oe.19.00b102Hayashi, T., Taru, T., Shimakawa, O., Sasaki, T., & Sasaoka, E. (2011). Design and fabrication of ultra-low crosstalk and low-loss multi-core fiber. Optics Express, 19(17), 16576. doi:10.1364/oe.19.016576Koshiba, M., Saitoh, K., Takenaga, K., & Matsuo, S. (2012). Analytical Expression of Average Power-Coupling Coefficients for Estimating Intercore Crosstalk in Multicore Fibers. IEEE Photonics Journal, 4(5), 1987-1995. doi:10.1109/jphot.2012.2221085Macho, A., Morant, M., & Llorente, R. (2015). Experimental evaluation of nonlinear crosstalk in multi-core fiber. Optics Express, 23(14), 18712. doi:10.1364/oe.23.018712Macho, A., Morant, M., & Llorente, R. (2016). Unified Model of Linear and Nonlinear Crosstalk in Multi-Core Fiber. Journal of Lightwave Technology, 34(13), 3035-3046. doi:10.1109/jlt.2016.2552958Mecozzi, A., Antonelli, C., & Shtaif, M. (2012). Coupled Manakov equations in multimode fibers with strongly coupled groups of modes. Optics Express, 20(21), 23436. doi:10.1364/oe.20.023436Mecozzi, A., Antonelli, C., & Shtaif, M. (2012). Nonlinear propagation in multi-mode fibers in the strong coupling regime. Optics Express, 20(11), 11673. doi:10.1364/oe.20.011673Mumtaz, S., Essiambre, R.-J., & Agrawal, G. P. (2013). Nonlinear Propagation in Multimode and Multicore Fibers: Generalization of the Manakov Equations. Journal of Lightwave Technology, 31(3), 398-406. doi:10.1109/jlt.2012.2231401Palmieri, L., & Galtarossa, A. (2014). Coupling Effects Among Degenerate Modes in Multimode Optical Fibers. IEEE Photonics Journal, 6(6), 1-8. doi:10.1109/jphot.2014.2343998Antonelli, C., Mecozzi, A., & Shtaif, M. (2015). The delay spread in fibers for SDM transmission: dependence on fiber parameters and perturbations. Optics Express, 23(3), 2196. doi:10.1364/oe.23.002196Marcuse, D. (1975). Coupled-Mode Theory for Anisotropic Optical Waveguides. Bell System Technical Journal, 54(6), 985-995. doi:10.1002/j.1538-7305.1975.tb02878.xWong, D. (1990). Thermal stability of intrinsic stress birefringence in optical fibers. Journal of Lightwave Technology, 8(11), 1757-1761. doi:10.1109/50.60576Gloge, D. (1971). Weakly Guiding Fibers. Applied Optics, 10(10), 2252. doi:10.1364/ao.10.002252Cartaxo, A. V. T., Luis, R. S., Puttnam, B. J., Hayashi, T., Awaji, Y., & Wada, N. (2016). Dispersion Impact on the Crosstalk Amplitude Response of Homogeneous Multi-Core Fibers. IEEE Photonics Technology Letters, 28(17), 1858-1861. doi:10.1109/lpt.2016.2573925Poole, C. D., & Favin, D. L. (1994). Polarization-mode dispersion measurements based on transmission spectra through a polarizer. Journal of Lightwave Technology, 12(6), 917-929. doi:10.1109/50.296179Karlsson, O., Brentel, J., & Andrekson, P. A. (2000). Long-term measurement of PMD and polarization drift in installed fibers. Journal of Lightwave Technology, 18(7), 941-951. doi:10.1109/50.850739Brodsky, M., Frigo, N. J., Boroditsky, M., & Tur, M. (2006). Polarization Mode Dispersion of Installed Fibers. Journal of Lightwave Technology, 24(12), 4584-4599. doi:10.1109/jlt.2006.88578