When we write vectors as matrices, we tend to write an $n$-dimensional vector vector as $n \times 1$ column matrix. We emphasize that the gradient vector is defined only for scalar-valued functions. For vector valued functions, we will stick with viewing the derivative as a matrix.
Gloomy Addiction Relapse Statistics. Drug and alcohol rehab statistics show that the percentage of people who will relapse after a period recovery ranges from 50% to 90%. This is a frightening statistic and it is often used as justification for those who wish to carry on with their addiction.
-- A 1999 study by the Journal of Consulting and Clinical Psychology found that rates of PTSD in Gulf War veterans increased significantly over time, with a rate of 3 percent for men, 8 percent for women immediately upon return from the war, climbing to 7 percent for men and 16 percent for women followed up 18 to 24 months later.