The IANA time zone database maps a name to the named location's historical and predicted clock shifts. This database is used by many computer software systems, including most Unix-like operating systems, Java, and the Oracle RDBMS; HP's "tztab" database is similar but incompatible. When temporal authorities change DST rules, zoneinfo updates are installed as part of ordinary system maintenance. In Unix-like systems the TZ environment variable specifies the location name, as in TZ=':America/New_York'. In many of those systems there is also a system-wide setting that is applied if the TZ environment variable isn't set: this setting is controlled by the contents of the /etc/localtime file, which is usually a symbolic link or hard link to one of the zoneinfo files. Internal time is stored in timezone-independent epoch time; the TZ is used by each of potentially many simultaneous users and processes to independently localize time display.
What environment variable defines a location's name?
TZ

Houston has mild winters in contrast to most areas of the United States. In January, the normal mean temperature at Intercontinental Airport is 53.1 F (11.7 C), while that station has an average of 13 days with a low at or below freezing. Snowfall is rare. Recent snow events in Houston include a storm on December 24, 2004 when one inch (2.5 cm) of snow accumulated in parts of the metro area. Falls of at least one inch on both December 10, 2008 and December 4, 2009 marked the first time measurable snowfall had occurred in two consecutive years in the city's recorded history. The coldest temperature officially recorded in Houston was 5 F (15 C) on January 18, 1940. Houston has historically received an ample amount of rainfall, averaging about 49.8 in (1,260 mm) annually per 19812010 normals. Localized flooding often occurs, owing to the extremely flat topography and widespread typical clay-silt prairie soils, which do not drain quickly.
How much rain does Houston usually get per year?
49.8 in

Sensory memory holds sensory information less than one second after an item is perceived. The ability to look at an item and remember what it looked like with just a split second of observation, or memorization, is the example of sensory memory. It is out of cognitive control and is an automatic response. With very short presentations, participants often report that they seem to "see" more than they can actually report. The first experiments exploring this form of sensory memory were conducted by George Sperling (1963) using the "partial report paradigm". Subjects were presented with a grid of 12 letters, arranged into three rows of four. After a brief presentation, subjects were then played either a high, medium or low tone, cuing them which of the rows to report. Based on these partial report experiments,Sperling was able to show that the capacity of sensory memory was approximately 12 items, but that it degraded very quickly (within a few hundred milliseconds). Because this form of memory degrades so quickly, participants would see the display but be unable to report all of the items (12 in the "whole report" procedure) before they decayed. This type of memory cannot be prolonged via rehearsal.
Can we control what is stored in our sensory memory?
It is out of cognitive control