Problem: It is best for the receiving antenna to match the polarization of the transmitted wave for optimum reception. Intermediate matchings will lose some signal strength, but not as much as a complete mismatch. A circularly polarized antenna can be used to equally well match vertical or horizontal linear polarizations. Transmission from a circularly polarized antenna received by a linearly polarized antenna (or vice versa) entails a 3 dB reduction in signal-to-noise ratio as the received power has thereby been cut in half.
What is used to match vertical and horizontal linear polarizations?
The answer is the following: circularly polarized

Problem: In 1998, Apple introduced its new iMac which, like the original 128K Mac, was an all-in-one computer. Its translucent plastic case, originally Bondi blue and later various additional colors, is considered an industrial design landmark of the late 1990s. The iMac did away with most of Apple's standard (and usually proprietary) connections, such as SCSI and ADB, in favor of two USB ports. It replaced a floppy disk drive with a CD-ROM drive for installing software, but was incapable of writing to CDs or other media without external third-party hardware. The iMac proved to be phenomenally successful, with 800,000 units sold in 139 days. It made the company an annual profit of US$309 million, Apple's first profitable year since Michael Spindler took over as CEO in 1995. This aesthetic was applied to the Power Macintosh and later the iBook, Apple's first consumer-level laptop computer, filling the missing quadrant of Apple's "four-square product matrix" (desktop and portable products for both consumers and professionals). More than 140,000 pre-orders were placed before it started shipping in September, and by October proved to be a large success.
What did the iMac need to use in order to write CDs or other media?
The answer is the following: external third-party hardware

Problem: During the Eastern Han, conscription could be avoided if one paid a commutable tax. The Eastern Han court favored the recruitment of a volunteer army. The volunteer army comprised the Southern Army (Nanjun ), while the standing army stationed in and near the capital was the Northern Army (Beijun ). Led by Colonels (Xiaowei ), the Northern Army consisted of five regiments, each composed of several thousand soldiers. When central authority collapsed after 189 AD, wealthy landowners, members of the aristocracy/nobility, and regional military-governors relied upon their retainers to act as their own personal troops (buqu ).
How could conscription into military service be avoided?
The answer is the following: one paid a commutable tax

Problem: Prior to 1948, approximately 800,000 Jews were living in lands which now make up the Arab world (excluding Israel). Of these, just under two-thirds lived in the French-controlled Maghreb region, 1520% in the Kingdom of Iraq, approximately 10% in the Kingdom of Egypt and approximately 7% in the Kingdom of Yemen. A further 200,000 lived in Pahlavi Iran and the Republic of Turkey. Today, around 26,000 Jews live in Arab countries and around 30,000 in Iran and Turkey. A small-scale exodus had begun in many countries in the early decades of the 20th century, although the only substantial aliyah came from Yemen and Syria. The exodus from Arab and Muslim countries took place primarily from 1948. The first large-scale exoduses took place in the late 1940s and early 1950s, primarily in Iraq, Yemen and Libya, with up to 90% of these communities leaving within a few years. The peak of the exodus from Egypt occurred in 1956. The exodus in the Maghreb countries peaked in the 1960s. Lebanon was the only Arab country to see a temporary increase in its Jewish population during this period, due to an influx of refugees from other Arab countries, although by the mid-1970s the Jewish community of Lebanon had also dwindled. In the aftermath of the exodus wave from Arab states, an additional migration of Iranian Jews peaked in the 1980s when around 80% of Iranian Jews left the country.[citation needed]
The only substantial aliyah came from where?
The answer is the following:
Yemen and Syria