The overuse of these sites on a daily basis has many negative effects on the physical and mental health of students making them lethargic and unmotivated to create contact with the people in person. The parents should check and balance on their children when they use the internet. They should be on guard whether they are using it for appropriate time period or not. The peers and teachers should also help students make them aware of the negative effects and explain what they are losing in the real world by sticking to these social networking sites.
Competitive and monopsony models offer different predictions about the employment effects of minimum wage changes. For minimum wage increases that push below-competitive wages toward competitive levels, monopsony models predict employment and/or hours will rise rather than fall. However, minimum wage increases above competitive levels will decrease employment, just as in the competitive model. The rise in employment in the first case will also expand industry output until the minimum wage equals the competitive wage and product prices should fall. In a classic monopsony, profits fall and the firms may exit in the long run. In new monopsony models, savings from decreased turnover may offset the profit effect. Unlike the competitive model, expenditures on general training may increase because the monopsony employer can capture some of the return.
In any case, there is nonetheless a good deal of evidence to indicate that modafinil is producing at least a portion of its wakefulness-promoting effects by acting as a DRI, or at least via activation of the dopaminergic system. In support of modafinil acting as a dopaminergic agent, its wakefulness-promoting effects are abolished in DAT knockout mice (although it is important to note that DAT knockout mice show D 1 and D 2 receptor and norepinephrine compensatory abnormalities, which might confound this finding), reduced by both D 1 and D 2 receptor antagonists (although conflicting reports exist),  and completely blocked by simultaneous inactivation of both D 1 and D 2 receptors.  In accordance, modafinil shows full stimulus generalization to other DAT inhibitors including cocaine, methylphenidate, and vanoxerine, and discrimination is blocked by administration of both ecopipam (SCH-39166), a D 1 receptor antagonist, and haloperidol , a D 2 receptor antagonist.  Partial substitution was seen with the DRA dextroamphetamine and the D 2 receptor agonist PNU-91356A , as well as with nicotine (which indirectly elevates dopamine levels through activation of nicotinic acetylcholine receptors ).