Sunglasses

Sunglasses may be made with either prescription or non-prescription lenses that are darkened to offer protection against bright visible light. Good quality sunglasses should also protect against ultraviolet light. Due to changes in the atmosphere, ultraviolet levels are much elevated than in the past and ultraviolet protection for eyes and skin is even more important. It is possible to have lenses that seem very dark and yet offer little ultraviolet protection. Sunglasses fluctuate greatly and many offer more style than protection.

Clock synchronization

Clock synchronization is a problem from computer science and engineering which deals with the idea that internal clocks of several computers may be different. Even when initially set accurately, real clocks will differ after some amount of time due to clock drift, caused by clocks counting time at slightly different rates. There are several problems that occur as a consequence of rate differences and several solutions, some being more appropriate than others in certain contexts.

A Personal portal

A Personal portal is a site on the World Wide Web that characteristically provides personalized capabilities to its visitors, given that a pathway to other content. It is intended to use distributed applications, different numbers and types of middleware and hardware to provide services from a number of different sources. In addition, business portals are intended to share collaboration in workplaces. A further business-driven requirement of portals is that the content be able to work on multiple platforms such as personal computers, personal digital assistants (PDAs), and cell phones.

Grafting

Grafting is a method of plant propagation extensively used in horticulture, where the tissues of one plant are encouraged to fuse with those of another. It is most usually used for the propagation of trees and shrubs grown commercially. In most cases, one plant is chosen for its roots, and this is called the stock or rootstock. The other plant is chosen for its stems, leaves, flowers, or fruits and is called the scion.In stem grafting, a common grafting method, a shoot of a chosen, desired plant cultivar is grafted onto the stock of another type. In another common form called budding, a dormant side bud is grafted on the stem of another stock plant, and when it has fused successfully, it is encouraged to grow by cutting out the stem above the new bud.For successful grafting to take place, the vascular cambium tissues of the stock and scion plants must be located in contact with each other. Both tissues must be kept alive till the graft has taken, typically a period of a few weeks. Successful grafting only requires that a vascular connection takes place between the two tissues. A physical weak point often still occurs at the graft, because the structural tissue of the two distinct plants, such as wood may not fuse.