I learned on Friday of the very sad and untimely death of my good friend David Broomhead. I first came upon Dave’s name when Roy Goodacre and I were working on neural networks in Aberystwyth, and discovered that the Radial Basis Function neural network method that Dave had co-invented  some ten years previously ran some 20-900 times quicker  than did the multilayer perceptrons we were previously using. When I moved to Manchester in 2002, it was natural then that I should seek him out for a scientific chat to see where we might have mutual interests. It soon emerged that we had in fact been at Oxford together (he a year ahead of me doing Chemistry, so as a biochemist we had not met), had a mutual friend in the form of another theoretical chemist who had cofounded the Uhuru wholefoods shop, and were both weekly commuters who had some free time in midweek evenings that would allow us to enjoy talking about science (sensu lato) over a beer.
Thus began a long and wholly enjoyable relationship in which we would meet in the ‘snug’ (quiet) bar of the local watering hole, the Lass o’ Gowrie to discuss numerical methods and their applications to biological problems (lots), as well as sport (a little) and politics (rather less). Ideas that seemed worth pursuing would be turned into grant proposals (5 successful ones running – an unheard-of strike rate for me) and over time, of course, the discussions turned further to the results of the systems we were by then studying.
Our co-published oeuvre [3-15] covers a wide range of activities, from ODE modelling to nonlinear dynamics to information theory, and appears below (and see here), and is in some sense a legacy. But what everyone who met him always recognised (and see here for a typical blog, from which I have copied the above picture of Dave) was that Dave was simply the nicest bloke you could imagine. I suspect this sprang in part from his roots, and from a lifelong socialism that was reflected in his patience (few were as bright as him, and he had to explain some very complex things to us, slowly) and his overwhelming humanity. Dave becoming ill coincided with my secondment to BBSRC, so I saw comparatively little of him from 2008-13, but was very pleased to see him again this year. We had initiated some cheminformatics plans based around his earlier work [16, 17] on dimensionality reduction, that I hope may continue. As phrased in the Tao Te Ching, “Work is done, then forgotten. Therefore it lasts for ever.” As shall my memories of some very happy times with a very brilliant, warm and special person.
 Broomhead DS, Lowe D: Multivariable function interpolation and adaptive networks. Complex Syst 1988; 2:321-355.
 Goodacre R, Timmins ÉM, Burton R, Kaderbhai N, Woodward AM, Kell DB, Rooney PJ: Rapid identification of urinary tract infection bacteria using hyperspectral whole-organism fingerprinting and artificial neural networks. Microbiology UK 1998; 144:1157-1170.
 Ashall L, Horton CA, Nelson DE, Paszek P, Ryan S, Sillitoe K, Harper CV, Spiller DG, Unitt JF, Broomhead DS, Kell DB, Rand D, Sée V, White MRH: Pulsatile stimulation determines timing and specificity of NFkappa-B-dependent transcription. Science 2009; 324:242-246.
 Herrgård MJ, Swainston N, Dobson P, Dunn WB, Arga KY, Arvas M, Blüthgen N, Borger S, Costenoble R, Heinemann M, Hucka M, Le Novère N, Li P, Liebermeister W, Mo ML, Oliveira AP, Petranovic D, Pettifer S, Simeonidis E, Smallbone K, Spasić I, Weichart D, Brent R, Broomhead DS, Westerhoff HV, Kırdar B, Penttilä M, Klipp E, Palsson BØ, Sauer U, Oliver SG, Mendes P, Nielsen J, Kell DB: A consensus yeast metabolic network obtained from a community approach to systems biology. Nat Biotechnol 2008; 26:1155-1160.
 Ihekwaba AEC, Broomhead DS, Grimley R, Benson N, Kell DB: Sensitivity analysis of parameters controlling oscillatory signalling in the NF-kappaB pathway: the roles of IKK and IkBa. Systems Biology 2004; 1:93-103.
 Ihekwaba AEC, Broomhead DS, Grimley R, Benson N, White MRH, Kell DB: Synergistic control of oscillations in the NF-kappaB signalling pathway. IEE Systems Biology 2005; 152:153-160.
 Li P, Dada JO, Jameson D, Spasic I, Swainston N, Carroll K, Dunn W, Khan F, Messiha HL, Simeonidis E, Weichart D, Winder C, Broomhead DS, Goble CA, Gaskell SJ, Kell DB, Westerhoff HV, Mendes P, Paton NW: Systematic integration of experimental data and models in systems biology. BMC Bioinformatics 2010; 11:582.
 Lüdtke N, Panzeri S, Brown M, Broomhead DS, Knowles J, Montemurro MA, Kell DB: Information-theoretic Sensitivity Analysis: a general method for credit assignment in complex networks. J Roy Soc Interface 2008; 5:223-235.
 Nelson DE, Ihekwaba AEC, Elliott M, Gibney CA, Foreman BE, Nelson G, See V, Horton CA, Spiller DG, Edwards SW, McDowell HP, Unitt JF, Sullivan E, Grimley R, Benson N, Broomhead DS, Kell DB, White MRH: Oscillations in NF-kappaB signalling control the dynamics of gene expression. Science 2004; 306:704-708.
 Smallbone K, Messiha HL, Carroll KM, Winder CL, Malys N, Dunn WB, Murabito E, Swainston N, Dada JO, Khan F, Pir P, Simeonidis E, Spasić I, Wishart J, Weichart D, Hayes NW, Jameson D, Broomhead DS, Oliver SG, Gaskell SJ, McCarthy JEG, Paton NW, Westerhoff HV, Kell DB, Mendes P: A model of yeast glycolysis based on a consistent kinetic characterization of all its enzymes. FEBS Lett 2013; 587:2832–2841.
 Smallbone K, Simeonidis E, Broomhead DS, Kell DB: Something from nothing: bridging the gap between constraint-based and kinetic modelling. FEBS J 2007; 274:5576-5585.
 Wang Y, Paszek P, Horton CA, Kell DB, White MRH, Broomhead DS, Muldoon MR: Interactions among oscillatory pathways in NF- kappa B signalling. BMC Syst Biol 2011; 5:23.
 Wang Y, Paszek P, Horton CA, Yue H, H.White MR, Kell DB, Muldoon MR, Broomhead DS: A systematic survey of the response of a model NF-kappaB signalling pathway to TNFalpha stimulation. J Theoret Biol 2012; 297:137-147.
 Yue H, Brown M, Knowles J, Wang H, Broomhead DS, Kell DB: Insights into the behaviour of systems biology models from dynamic sensitivity and identifiability analysis: a case study of an NF-kappaB signalling pathway Mol Biosyst 2006; 2:640-649.
 Yue H, Wang Y, Broomhead DS, Brown M, Kell DB: Sensitivity analysis of an oscillatory signal transduction pathway. FOSBE2007 2007:99-104.
 Broomhead DS, Kirby M: A new approach to dimensionality reduction: theory and algorithms. SIAM J Appl Math 2000; 60:2114-2142.
 Broomhead DS, Kirby MJ: The Whitney reduction network: a method for computing autoassociative graphs. Neural Comp 2001; 13:2595-2616.