Nicotine withdrawal symptoms include depressed mood, stress, anxiety, irritability, difficulty concentrating, and sleep disturbances. Emotional effects can include a fear of death, sadness, memory problems and difficulty in concentrating. The initial instruction requires standing still and concentrating on posture, rather than dancing. Some of these symptoms include fatigue, loss of appetite, depression, and trouble concentrating. Nokia announced it will be primarily concentrating on their alliance with Microsoft. Durruti was concentrating himself on helping the collective. We should be concentrating our efforts on renewables and greater energy conservation. We were concentrating strictly in Cuba at that particular time. He was now concentrating entirely on a jazz approach. He goes back to concentrating on his studies and his new job instead. The increase in intensity is typically accomplished by using concentrating optics. Heating the water can be achieved through the use of concentrating solar power. JVKV are also individually concentrating on their solo careers in both acting and music. They hoped to achieve a breakthrough by concentrating their mass on a narrow front. State governors resisted concentrating a national effort.