Accuracy of a method based on atomic absorption spectrometry to determine inorganic arsenic in food : Outcome of the collaborative trial IMEP-41

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Multimode Interference In Tapered Single Mode-multimode-single Mode Fiber Structures For Strain Sensing Applications

Tapering single mode-multimode-single mode structures to enhance sensitivity is proposed and experimentally demonstrated. 50 mm-long coreless MMF sections are spliced between SMFs and tapered. They are characterized in strain and an increase in strain sensitivity is obtained with taper diameter reduction. Sensitivities as high as -23.69 pm/με for the 15 μm taper are attained. A combination of an untapered and tapered SMS is proposed as a sensing system for the simultaneous measurement of strain and temperature. © 2012 SPIE.8421Soldano, L., Pennings, E., Optical multi-mode interference devices based on self-imaging: Principles and applications (1995) Lightwave Technology, Journal of, 13, pp. 615-627. , AprilKumar, A., Varshney, R.K., Sharma, P., Transmission characteristics of sms fiber optic sensor structures (2003) Optics Communications, 219, pp. 215-219Wang, Q., Farrell, G., Yan, W., Investigation on single-mode-multimode-single-mode fiber structure (2008) J. Lightwave Technol., 26, pp. 512-519. , MarMehta, A., Mohammed, W., Johnson, E., Multimode interference-based fiber-optic displacement sensor (2003) Photonics Technology Letters, IEEE, 15, pp. 1129-1131. , augMohammed, W., Mehta, A., Johnson, E., Wavelength tunable fiber lens based on multimode interference (2004) Lightwave Technology, Journal of, 22, pp. 469-477. , febFrazão, O., Silva, S.O., Viegas, J., Ferreira, L.A., Araújo, F.M., Santos, J.L., Optical fiber refractometry based on multimode interference (2011) Appl. Opt., 50, pp. E184-E188. , SepMohammed, W.S., Smith, P.W.E., Gu, X., All-fiber multimode interference bandpass filter (2006) Opt. Lett., 31, pp. 2547-2549. , SepWang, Q., Farrell, G., Multimode-fiber-based edge filter for optical wavelength measurement application and its design (2006) Microwave and Optical Technology Letters, 48 (5), pp. 900-902Wang, P., Brambilla, G., Ding, M., Semenova, Y., Wu, Q., Farrell, G., High-sensitivity, evanescent field refractometric sensor based on a tapered, multimode fiber interference (2011) Opt. Lett., 36, pp. 2233-2235. , JunFrazão, O., Silva, S.F.O., Guerreiro, A., Santos, J.L., Ferreira, L.A., Araújo, F.M., Strain sensitivity control of fiber bragg grating structures with fused tapers (2007) Appl. Opt., 46 (36), pp. 8578-8582Biazoli, C.R., André, R.M., Frazão, O., Cordeiro, C.M.B., Tapering down optical fiber to ultra-high strain sensitivity (2012) Photonics Technology Letters, IEEE, , Submitte

Multiple drivers of decline in the global status of freshwater crayfish (Decapoda: Astacidea)

International audienceRates of biodiversity loss are higher in freshwater ecosystems than in most terrestrial or marine ecosystems, making freshwater conservation a priority. However, prioritization methods are impeded by insufficient knowledge on the distribution and conservation status of freshwater taxa, particularly invertebrates. We evaluated the extinction risk of the world's 590 freshwater crayfish species using the IUCN Categories and Criteria and found 32% of all species are threatened with extinction. The level of extinction risk differed between families, with proportionally more threatened species in the Parastacidae and Astacidae than in the Cambaridae. Four described species were Extinct and 21% were assessed as Data Deficient. There was geographical variation in the dominant threats affecting the main centres of crayfish diversity. The majority of threatened US and Mexican species face threats associated with urban development, pollution, damming and water management. Conversely, the majority of Australian threatened species are affected by climate change, harvesting, agriculture and invasive species. Only a small proportion of crayfish are found within the boundaries of protected areas, suggesting that alternative means of long-term protection will be required. Our study highlights many of the significant challenges yet to come for freshwater biodiversity unless conservation planning shifts from a reactive to proactive approach