DR. RAPHAEL LINKER
Personal Background
Date and place of birth: July 8, 1967; Belgium Marital status: Married + 3
Academic Degrees
2000 PhD, Faculty of Agricultural Engineering, Technion – IIT
1995 MSc, Faculty of Agricultural Engineering, Technion – IIT
1990 Diplôme d’Ingénieur Civil, Faculty of Electro-Mechanical Engineering, Brussels Free University
Current Position
2005 – present Senior Lecturer, Faculty of Civil and Environmental Engineering, Technion – IIT
Research Interests
Mid-infrared spectroscopy-based sensing for agricultural and environmental systems. Emphasis on data processing and on-line measurements
Modeling, control and optimization of agricultural and environmental systems Hyperspectral and fluorescence imaging
Honors and Awards
2003 – 2004 Technion. Zeff Post-doctoral Fellowship
2002 – 2003 Technion. Lady Davis Post-doctoral Fellowship
2000 AgriControl 2000 Conference, Wageningen (The Netherlands). Best Paper Award
1998 Technion Gutwirth Award for achievement in studies
1993 Technion Teaching Assistant Technion Award
List of Recent Publications
1. (a) Etzion Y., R. Linker, U. Kogan and I. Shmulevich (2004). Determination of protein concentration in raw milk by mid-infrared Fourier transform infrared/attenuated total reflectance spectroscopy. Journal of Dairy Science, 87:2779-2788.
2. Linker R. (2004). Wavebands selection for determination of nitrate in soil using mid-IR/ATR spectroscopy. Applied Spectroscopy, 58(11):1277-1281.
3. Linker R. and L. S. Katzman (2004). Detection of root disease in hydroponic spinach by monitoring dissolved oxygen in nutrient solution. International Agricultural Engineering Journal, 13(3):87-92.
4. Linker R., A. Kenny, A. Shaviv, L. Singher and I. Shmulevich (2004). FTIR/ATR nitrate determination of soil pastes using PCR, PLS and cross-correlation. Applied Spectroscopy, 58(5):516-520.
5. Linker R. and I. Seginer (2004). Greenhouse temperature modeling: A comparison between sigmoid neural networks and hybrid models. Mathematics and Computers in Simulation, 65:19-29.
6. Linker R., I. Seginer and F. Buwalda (2004). Description and calibration of a dynamic model for lettuce grown in a nitrate-limiting environment. Mathematical and Computer Modelling, 40: 1009-1024.
7. Linker R. (2005). Spectrum analysis by recursively pruned extended auto-associative neural network. Journal of Chemometrics, 19: 492-499.
8. Linker R. and C. Johnson-Rutzke (2005). Modeling the effect of abrupt changes in nitrogen availability on lettuce growth, root-shoot partitioning and nitrate concentration. Agricultural Systems, 86: 166-189.
9. Linker R., I. Shmulevich, A. Kenny and A. Shaviv (2005). Soil identification and chemometrics for direct determination of nitrate in soils using FTIR-ATR mid-infrared spectroscopy. Chemosphere, 61: 652-658.
10. (a) Borenstein A., R. Linker, I. Shmulevich and A. Shaviv (2006). Determination of soil nitrate and water content using attenuated total reflectance spectroscopy. Applied Spectroscopy, 60: 1267-1272.
11. (b) Fan L., R. Linker, S. Gepstein, E. Tanimoto, R. Yamamoto and P. M. Neumann (2006). Progressive inhibition by water deficit of cell wall extensibility and growth along the elongation zone of maize roots is related to increased lignin metabolism and progressive stelar accumulation of wall phenolics. Plant Physiology, 140: 603-612.
12. (b) Jahn B. R., R. Linker R., S. K. Upadhyaya, A. Shaviv, D. C. Slaughter and I. Shmulevich (2006). Mid infrared spectroscopic determination of soil nitrate content. Biosystems Engineering, 94: 505-515.
15. (a) Mathieu J., R. Linker, L. Levine, L. Albright. A.J. Both, R. Spanswick, R. Wheeler, E. Wheeler, D. deVilliers and R. Langhans (2006). Evaluation of the NiCoLet Model for Simulation of Short-Term Hydroponic Lettuce Growth andNitrate Uptake. Biosystems Engineering, 95: 323-337.
16. (a) Du, C., R. Linker and A. Shaviv (2007). Characterization of soils using photoacoustic mid-infrared spectroscopy. Applied Spectroscopy, 61: 1063-1067.
17. (a) Du, C., R. Linker and A. Shaviv (2008). Identification of agricultural Mediterranean soils using mid-infrared photoacoustic spectroscopy. Geoderma, 143: 85-90.
18. Linker, R (2008). Determination of nitrate concentration in soil via photoacoustic spectroscopy analysis of ion exchange membranes. Applied Spectroscopy, 62: 302-305.
Abstracts
Determination of soil nitrate and water content using attenuated total reflectance spectroscopy
A. Borenstein, R. Linker,* I. Shmulevich, and A. Shaviv
Division of Environmental, Water and Agricultural Engineering; Faculty of Civil and Environmental Engineering; Technion-Israel Institute of Technology, Haifa 32000, Israel
Applied Spectroscopy Volume 60, Number 11, 2006
Direct determination of nitrate and soil moisture can significantly improve N-application management and thus reduce N-derived environmental pollution related to agriculture. Several studies have shown that Fourier transform infrared attenuated total reflectance (FT-IR/ATR) spectroscopy could be used to estimate the nitrate content of standardized soil pastes. Paste standardization appeared to be the main obstacle to in situ application of this approach, and the present study shows how FT-IR/ATR can be used to estimate both water content and nitrate concentration of field soil samples.Water content and nitrate concentration are determined sequentially using two subsamples of the initial soil sample. An a priori determined amount of highly concentrated nitrate solution is added to the first subsample and the ATR spectrum of this paste is used to estimate the sample water content. It is then possible to calculate the amount of water that should be added to the second subsample so that the resulting paste is very close to the ideal standard paste. Nitrate concentration, mg [N]/kg [dry soil], is estimated using the FT-IR/ATR spectrum of this second paste. Results are presented for a laboratory experiment with four agricultural soils, as well as for a field trial with a calcareous soil. For water content, the determination errors range from 0.01 to 0.02 g [water]/g [dry soil]. For nitrate concentration, the errors for three of the soils range from 5.9 to 8.4 mg [N]/kg [dry soil], while for the fourth, calcareous clay soil the determination error is 13.6 mg [N]/kg [dry soil]. The determination errors obtained for the field trial are similar to the ones obtained for a similar soil under laboratory conditions, which shows the potential usefulness of the approach for improving N-application management and reducing environmental pollution.
Evaluation of the Nicolet model for simulation of short-term hydroponic lettuce growth and nitrate uptake
Jennifer Mathieu1; Raphael Linker2; Lanfang Levine3; Louis Albright4; A.J. Both5; Roger Spanswick4; Raymond Wheeler6; Eileen Wheeler7; David deVilliers4; Robert Langhans8
Biosystems Engineering 95 (3), 323–337, 2006
Accurate simulation models for short-term (_hours) changes in hydroponic crop growth and nitrate uptake are needed for rapid fault detection in hydroponic systems. Comparison between model-predicted and measured values for crop growth and nitrate uptake is proposed as the basis for such a fault detection system.
provided evidence of short-term behaviour, including statistically significant predictions of diurnal patterns. This is a first step in realising fault detection systems based on mechanistic simulation models.
Mid-infrared spectroscopic determination of soil nitrate content
B.R. Jahn1; R. Linker2; S.K. Upadhyaya1; A. Shaviv2; D.C. Slaughter1; I. Shmulevich2
1
Department of Biological and Agricultural Engineering, University of California, Davis, CA 95616, USA; e-mail of corresponding author: [email protected]
2Faculty of Civil and Environmental Engineering, Lowdermilk Division of Agricultural Engineering, Technion-Israel
Institute of Technology, Haifa 32000, Israel
Biosystems Engineering 94 (4), 505–515, 2006
(Received 22 September 2005; accepted in revised form 17 May 2006; published online 14 July 2006)
Mid-infrared (mid-IR) spectroscopy experiments were conducted to detect added nitrate in various soil types both in the laboratory and field. Soil pastes from ten different soils, including sandy loam, clay, and peat soils, were analysed for soil nitrate contents using the Fourier transform infrared (FTIR) attenuated total reflectance (ATR) technique. Nitrate concentrations for
the laboratory experiments varied from approximately 0–1000 ppm. NO3-N while concentrations
for the field experiments varied from approximately 0–140 ppm. NO3-N. Three-dimensional plots
were created by graphing the wavelet deconvoluted values at 32 scales for each sample. From each plot, the volume of the nitrate peak was determined and correlated to nitrate concentrations. Results of the laboratory experiments indicated values for the coefficient of determination R2 as
high as 0_99 and standard errors as low as 24 ppm. NO3-N for soil-specific calibrations. Results
of the field experiments gave values for R2 as high as 0_98 and standard errors as low as 5 ppm NO3-N for soil-specific calibrations. An alternative technique to determine nitrate content was developed in which wavelet analysis was used to identify a few wavenumbers at which interferences from other ions were minimal. This method produced calibration equations that were soil independent and gave superior results to those obtained based on correlating wavelet deconvoluted volumes to nitrate concentrations.
Nitrate determination using anion exchange membrane and mid-infrared spectroscopy
Raphael Linker* and Avi Shaviv
Faculty of Civil and Environmental Engineering, Division of Environmental, Water and Agricultural Engineering, Technion-Israel Institute of Technology, Haifa 32000, Israel
Applied Spectroscopy Volume 60, Number 9, 2006
correlation between the nitrate charge and the absorbance in the 1000–1070 cm_1 interval, which includes the m1 nitrate band located around 1040 cm_1. The prediction errors range from 0.8 to 2.1 leq, which, under the specific experimental conditions, corresponds to approximately 2 to 6 ppm N– NO3_ on a solution basis or 2 to 5 mg [N]/kg [dry soil] on a dry soil basis. Index
Headings: Nitrate fertilization management; Partial least squares;
Nitrate determination in soil pastes using attenuated total reflectance mid-infrared spectroscopy: Improved accuracy via soil identification
R. Linker; M. Weiner; I. Shmulevich; A. Shaviv
Division of Environmental, Water and Agricultural Engineering; Faculty of Civil and Environmental Engineering; Technion-Israel Institute of Technology; e-mail of corresponding author: [email protected]
Biosystems Engineering 94 (1), 111–118, 2006
(Received 11 April 2005; accepted in revised form 25 January 2006; published online 15 March 2006)
Progressive inhibition by water deficit of cell wall extensibility and growth along the elongation zone of maize roots is related to increased lignin metabolism and progressive stelar accumulation of wall phenolics1
Ling Fan, Raphael Linker, Shimon Gepstein, Eiichi Tanimoto, Ryoichi Yamamoto, and Peter M. Neumann*
Plant Physiology Laboratory, Department of Environmental, Water, and Agricultural Engineering, Faculty of Civil and Environmental Engineering (L.F., R.L., P.M.N.) and Faculty of Biology (S.G.), Technion-Israel
Institute of Technology, Haifa 32000, Israel; Plant Physiology Laboratory, Department of Information and Biological Sciences, Graduate School of Natural Sciences, Nagoya City University, Nagoya 467–8501, Japan (E.T.); and Biology and Chemistry Laboratory, Tezukayama University, Nara 631–8585, Japan (R.Y.)
Plant Physiology Vol. 140, pp. 603–612, February 2006
Water deficit caused by addition of polyethylene glycol 6000 at 20.5 MPa water potential to well-aerated nutrient solution for 48 h inhibited the elongation of maize (Zea mays) seedling primary roots. Segmental growth rates in the root elongation zone were maintained 0 to 3 mm behind the tip, but in comparison with well-watered control roots, progressive growth inhibition was initiated by water deficit as expanding cells crossed the region 3 to 9 mm behind the tip. The mechanical extensibility of the cell walls was also progressively inhibited. We investigated the possible involvement in root growth inhibition by water deficit of alterations in metabolism and accumulation of wall-linked phenolic substances. Water deficit increased expression in the root elongation zone of transcripts of two genes involved in lignin biosynthesis, cinnamoyl-CoA reductase 1 and 2, after only 1 h, i.e. before decreases in wall extensibility. Further increases in transcript expression and increased lignin staining were detected after 48 h. Progressive stress-induced increases in wall-linked phenolics at 3 to 6 and 6 to 9 mm behind the root tip were detected by comparing Fourier transform infrared spectra and UV-fluorescence images of isolated cell walls from water deficit and control roots. Increased UV fluorescence and lignin staining colocated to vascular tissues in the stele. Longitudinal bisection of the elongation zone resulted in inward curvature, suggesting that inner, stelar tissues were also rate limiting for root growth.We suggest that spatially localized changes in wall-phenolic metabolism are involved in the progressive inhibition of wall extensibility and root growth and may facilitate root acclimation to drying environments.
Characterization of soils using photoacoustic mid-infrared spectroscopy
Du Changwen, Raphael Linker,* and Avi Shaviv
National Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China (D.C.); and Faculty of Civil and Environmental Engineering, Technion-Israel Institute of Technology, Haifa 32000, Israel (R.L., A.S.)
Applied Spectroscopy Volume 61, Number 10, 2007
the ATR spectra due to the strong water bands present in the latter. PAS quantitative analysis of clay, calcium carbonate, and organic matter is presented, with respective determination errors of
