Katepalli Sreenivasan pays tribute to Denardo's enormous contribution to the field of optics, and shares his sadness at the death of his friend.

In writing about my friend Gallieno Denardo, I have had to resist the temptation to write in the present tense, as if he is still with us - as if he will somehow show up in my office and fill it with his boisterous, if somewhat nervous, laughter. Alas, that will never happen again.

Monday 23 July was Gallieno's 72nd birthday. I sent him a brief e-greeting some time that afternoon. He had been housebound for more than a week because of an accident and I didn't expect an immediate response. I hadn't received anything from him by the next morning. At around 10.00 a.m. on the 24th I learned that Gallieno was no more. He had likely passed away just around the time I sent my e-mail.

At first I could not believe the news of Gallieno's death because it seemed so unlikely and untimely. I hoped against hope that someone might show up to reassure me that this terrible news was not true. But, alas, it was true and there was nothing left to do but stare into endless emptiness.

I had had lunch with Gallieno just the previous Friday and had mentioned to him that he had probably missed the ICTP more than the ICTP had missed him during his absence. When I drove him from Adriatico to the Main Building, he alighted from the car with some difficulty and walked slowly on his crutches, but he gave no indication of anything more than modest discomfort. If it is true that gentle death without suffering befalls only generous people, there was abundant proof in death, as in life, that Gallieno was unreservedly generous to all. I know for a fact that he always thought in terms of how he could be useful to others in need, never asking how his actions would serve his strategic advantage.

When I came for my first formal visit to the ICTP, still unsure if I would accept the position of ICTP director, Gallieno was one of the people who tipped my decision in favour. He convinced me that it would indeed be possible to set up an experimental research programme at the ICTP (he took me to Elettra and the Optics Lab), and explained why someone like me would be good for the ICTP at that time. Later he was like an older brother to me, giving guidance and advice when asked, rarely pushing a personal agenda and never demanding things in return. He made me feel good about myself on occasion - heaven knows that there are many reasons to feel otherwise - and provided as input his immense experience when critical decisions had to be made.

Now that Gallieno is gone for good I have to find people to take on all of the responsibilities that he shouldered so capably without pretence. No doubt the ICTP will rise to the occasion and things will turn out fine at some level, but it will never be the same without him. We will miss the wealth of information that resided in Gallieno's mind, and the compassion and effectiveness with which he used it.

Africa Day
Recently the ICTP celebrated Africa Day at the instance of the Africa department of the Italian Ministry of Foreign Affairs. Several African scientists, young and old, spoke at the meeting. For those who knew of Gallieno's involvement in Africa it came as no surprise that the meeting turned out, unplanned, to celebrate Gallieno's contributions to African science. Nearly everyone acknowledged the warmth and personal involvement that he invested in the ICTP's projects in Africa. In his usual unassuming way, he brushed off this honour simply by saying that people were exaggerating. Those who knew the details were aware that the truth was different: Gallieno deserved everything that was said of him that day.

Katepalli Sreenivasan (left) and Gallieno Denardo celebrate Africa Day on 23 May 2007 at ICTP, Trieste.

Patient and pragmatic
Gallieno did many things for the ICTP but this is no place to attempt a list. I should, however, mention three aspects: the Office of External Activities (OEA); his mentoring of an important training activity on lasers and optics; and his special interest in eastern Europe. In all of these his vision was not grandiose but pragmatic and practical. He built the OEA over time and with patience, and he cultivated deserving scientists all over the world. He was keenly aware of their shortcomings and knew their little problems and difficulties, but he also knew what measures would be appropriate to solve them. Even though his own field of research was not optics he saw its importance for a number of areas of basic sciences and, through the involvement of many interested people over the world, created a great optics community around the ICTP. For areas in which the ICTP does not have local expertise, as has been the case with lasers and optics, I believe this to be the most effective way to forge ahead. Gallieno had strong feelings for central European cultures, particularly Slavic (he spoke fluent Slovenian), and he devoted much energy to creating strong links with the ICTP. Naturally he had many friends in that part of the world. He was also keen to nurture the ICTP's relationships with the International Atomic Energy Agency, which he considered vital and strategic.

I know that different people have their different ideas of what happens after death. I must confess that I don't know my own thinking well in this respect - let alone knowing about those of others. However, if it is true that there is a soul that survives the collapse of the physical body, I have no doubt that Gallieno's soul hovers over the ICTP, taking pride in its accomplishments and cheering us on to do better when it falls short of expectations. But he would be neither jealous nor complaining. That thought lessens my sadness at the knowledge of his death.

Katepalli R Sreenivasan, ICTP director and Abdus Salam honorary professor.