One of the features that makes the hydroboration reaction so useful is the regiochemistry that results when an unsymmetrical alkene is hydroborated. For example, hydroboration-oxidation of 1-methylcyclopentene yields trans-2-methylcyclopentanol. Boron and hydrogen add to the alkene with syn stereochemistry, with boron attaching to the less highly substituted carbon. During the oxidation step, the boron is […] Read more

First, hydrocarbons, or compounds that could have been converted into hydrocarbons at the intense pressures of the earth’s depths, must have been a common constituent of the primordial materials out of which the earth was formed. Second, in the four and a half billion years since the earth accreted, the primordial hydrocarbons must not subsequently […] Read more

As you can see in Figure 3-1, a bar is fixed at one and is set into vibration by tapping it from the bottom. Imagine that a strobe light is used to take a series of snapshots of the bar as it vibrates up and down. At each snapshot the instantaneous displacement of the bar […] Read more

In one 24-hour day, Sam took 3 naps for: 1 hour, 2 minutes, 2 hours, 58 minutes, and 1 hour, 11 minutes. How many hours was Sam awake? You’re right! Hmmm… try again. Time’s almost up… want a hint […] Read more

In the beginnings of international trade the older countries exchange their products for the raw materials and food produced by the new ones. Then, as emigrants from the old countries go out into the new ones, they want to be supplied with the comforts and appliances of the older civilizations, such as, to take an […] Read more

This chapter provides technical information about fall hazards and protection methods. The information is intended to help prepare OSHA compliance officers to conduct inspections and investigations. For convenience, links are provided to applicable OSHA standards throughout this chapter. This chapter does not cover all OSHA requirements for fall prevention/protection methods, and is not intended to […] Read more

In the next 15 minutes, you will learn the four steps towards a better retirement. An IRA will be a key player in almost any retirement plan. Here are some steps you can take now to make your IRA work harder for you and help secure a more comfortable retirement. The earlier you start contributing […] Read more

Fitness that’s invigorating, not intimidating! This 60-minute class pairs moderate aerobics with exercises designed to improve your strength, balance, and flexibility. Whether you’re a senior, newcomer, pregnant, or prefer low impact, you can’t go wrong with this popular light version of the original Jazzercise program. We begin the workout with some good old warm-ups […] Read more

Thank you. I’ve always believed in numbers and the equations and logics that lead to reason. But after a lifetime of such pursuits, I ask, “What truly is logic? Who decides reason?” My quest has taken me through the physical, the metaphysical, the delusional — and back. And I have made the most important discovery […] Read more