During the past three decades there has been a large amount of research on biological nitrogen fixation, in part stimulated by increasing world prices of nitrogen-containing fertilizers and environmental concerns. In the last several years, research on plant-microbe interactions, and symbiotic and asymbiotic nitrogen fixation has become truly interdisciplinary in nature, stimulated to some degree by the use of modern genetic techniques. These methodologies have allowed us to make detailed analyses of plant and bacterial genes involved in symbiotic processes and to follow the growth and persistence of the root-nodule bacteria and free-living nitrogen-fixing bacteria in soils. Through the efforts of a large number of researchers we now have a better understanding of the ecology of rhizobia, environmental parameters affecting the infection and nodulation process, the nature of specificity, the biochemistry of host plants and microsymbionts, and chemical signalling between symbiotic partners. This volume gives a summary of current research efforts and knowledge in the field of biological nitrogen fixation. Since the research field is diverse in nature, this book presents a collection of papers in the major research areas of physiology and metabolism, genetics, evolution, taxonomy, ecology, and international programmes.

Depression has colonized the world. Today, more than 300 million of us have been diagnosed as depressed. But 150 years ago, "depression" referred to a mood, not a sickness. Does that mean people weren't sick before, only sad? Of course not. Mental illness is a complex thing, part biological, part social, its definition dependent on time and place. But in the mid-twentieth century, even as European empires were crumbling, new Western clinical models and treatments for mental health spread across the world. In so doing, "depression" began to displace older ideas like "melancholia," the Japanese "utsusho," or the Punjabi "sinking heart" syndrome. Award-winning historian Jonathan Sadowsky tells this global story, chronicling the path-breaking work of psychiatrists and pharmacists, and the intimate sufferings of patients. Revealing the continuity of human distress across time and place, he shows us how different cultures have experienced intense mental anguish, and how they have tried to alleviate it. He reaches an unflinching conclusion: the devastating effects of depression are real. A number of treatments do reduce suffering, but a permanent cure remains elusive. Throughout the history of depression, there have been overzealous promoters of particular approaches, but history shows us that there is no single way to get better that works for everyone. Like successful psychotherapy, history can liberate us from the negative patterns of the past.