Negative reinforcement

It is a bad idea to take drugs in school. Even if school bores you, you have to be there, and mastering classroom skills is your ticket to freedom and independence in adult life. Drugs can interfere with your education by making it hard to pay attention, concentrate, and remember, or by involving you with people who reinforce negative attitudes about school. 

In all three frontier orbital combinations shown above, the upper orbital components are the same sign, and their overlap is positive. In the two cases on the left, the lower orbital components also lead to positive overlap. Thus, the upper and lower interactions reinforce, and the total frontier orbital interaction is non-zero. Electron movement (chemical reaction) can occur. The right-most case is different. Here the lower orbital components lead to negative overlap (the orbitals have opposite signs at the interacting sites), and the total overlap is zero. No electron movement and no chemical reaction can occur in this case. 

For pipelines to be placed under water, it is necessary to provide negative buoyancy. This is commonly achieved by placing lightly reinforced concrete up to 150 mm thick over the 3-5 mm hot enamal coating on the steel. Joints at the welded tube ends have to be coated with a minimum of delay due to the high production rate required on the laying barge, and tapes have therefore found application at this point. Where submarine pipelines are pulled ... 

Although the evidence base for this relatively rare disorder is not well developed, patients who are dependent on GHB appear to benefit from cognitive and motivational psychosocial therapies and from support of recovery in a manner similar to alcohol-dependent patients. However, because of the high likelihood of amnesia and cognitive dysfunction during the acute and subacute phases of GHB withdrawal, psychosocial interventions should, when possible, include significant others who can review and reinforce with the patient the negative consequences of GHB dependence. 

The phase-twisted peak shapes (or mixed absorption-dispersion peak shape) is shown in Fig. 3.9. Such peak shapes arise by the overlapping of the absorptive and dispersive contributions in the peak. The center of the peak contains mainly the absorptive component, while as we move away from the center there is an increasing dispersive component. Such mixed phases in peaks reduce the signal-to-noise ratio complicated interference effects can arise when such lines lie close to one another. Overlap between positive regions of two different peaks can mutually reinforce the lines (constructive interference), while overlap between positive and negative lobes can mutually cancel the signals in the region of overlap (destructive interference). 

Since the core polarization will give a negative spin density at the iron nucleus, it is expected that in the state the isotropic and dipolar contributions partially cancel each other along the Fe-O bond direction while they will reinforce each other along this direction in the state. 

Hydroboration is highly regioselective and stereospecific. The boron becomes bonded primarily to the less-substituted carbon atom of the alkene. A combination of steric and electronic effects works to favor this orientation. Borane is an electrophilic reagent. The reaction with substituted styrenes exhibits a weakly negative p value (-0.5).156 Compared with bromination (p+ = -4.3),157 this is a small substituent effect, but it does favor addition of the electrophilic boron at the less-substituted end of the double bond. In contrast to the case of addition of protic acids to alkenes, it is the boron, not the hydrogen, that is the more electrophilic atom. This electronic effect is reinforced by steric factors. Hydroboration is usually done under conditions in which the borane eventually reacts with three alkene molecules to give a trialkylborane. The... 

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