sadness

n.

悲哀，忧伤，忧愁，悲哀；令人悲哀或忧伤的事物；愁眉苦脸，心境恶劣，心情恶劣；认真

1. His sudden death was occasion for much sadness.
   他的突然死亡是很多的悲哀场合。
2. Try to pin down the exact quality of its sadness.
   努力弄清楚它的确切的悲哀特点。

Attachment and Loss: Sadness and Depression by John Bowlby
Attachment and loss: Loss, sadness and depression (Vol. 3)
Brain activity during transient sadness and happiness in healthy women.
Neuroanatomical correlates of happiness, sadness, and disgust.
Beyond simple pessimism: Effects of sadness and anger on social perception.
Dissociable neural responses to facial expressions of sadness and anger
Anger and advancement versus sadness and subjugation: the effect of negative emotion expressions on social status conferral
Negative affect and social judgment: The differential impact of anger and sadness
Differential limbic--cortical correlates of sadness and anxiety in healthy subjects: implications for affective disorders.
Reciprocal limbic-cortical function and negative mood: Converging PET findings in depression and normal sadness.