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Bridgewater is a town in Aroostook County, Maine, United States. The population was 532 at the 2020
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census.
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Geography
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According to the United States Census Bureau, the town has a total area of , of which is land and
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is water.
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Climate
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This climatic region is typified by large seasonal temperature differences, with warm to hot (and
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often humid) summers and cold (sometimes severely cold) winters. According to the Köppen Climate
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Classification system, Bridgewater has a humid continental climate, abbreviated "Dfb" on climate
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maps.
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Demographics
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2010 census
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As of the census of 2010, there were 610 people, 263 households, and 175 families living in the
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town. The population density was . There were 326 housing units at an average density of . The
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racial makeup of the town was 96.7% White, 0.7% Native American, 0.2% Asian, 1.0% from other races,
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and 1.5% from two or more races. Hispanic or Latino of any race were 1.1% of the population.
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There were 263 households, of which 25.9% had children under the age of 18 living with them, 55.5%
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were married couples living together, 8.4% had a female householder with no husband present, 2.7%
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had a male householder with no wife present, and 33.5% were non-families. 29.7% of all households
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were made up of individuals, and 14.4% had someone living alone who was 65 years of age or older.
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The average household size was 2.32 and the average family size was 2.90.
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The median age in the town was 46.7 years. 22.5% of residents were under the age of 18; 4.4% were
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between the ages of 18 and 24; 20.7% were from 25 to 44; 32.7% were from 45 to 64; and 19.8% were
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65 years of age or older. The gender makeup of the town was 50.0% male and 50.0% female.
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2000 census
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As of the census of 2000, there were 612 people, 248 households, and 173 families living in the
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town. The population density was 15.8 people per square mile (6.1/km2). There were 316 housing
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units at an average density of 8.1 per square mile (3.1/km2). The racial makeup of the town was
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98.04% White, 0.49% Native American, 0.65% from other races, and 0.82% from two or more races.
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Hispanic or Latino of any race were 0.65% of the population.
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There were 248 households, out of which 27.0% had children under the age of 18 living with them,
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59.3% were married couples living together, 6.0% had a female householder with no husband present,
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and 30.2% were non-families. 25.4% of all households were made up of individuals, and 12.9% had
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someone living alone who was 65 years of age or older. The average household size was 2.47 and the
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average family size was 2.97.
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In the town, the population was spread out, with 22.2% under the age of 18, 5.6% from 18 to 24,
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25.0% from 25 to 44, 26.6% from 45 to 64, and 20.6% who were 65 years of age or older. The median
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age was 43 years. For every 100 females, there were 101.3 males. For every 100 females age 18 and
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over, there were 94.3 males.
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The median income for a household in the town was $27,679, and the median income for a family was
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$33,125. Males had a median income of $24,167 versus $21,190 for females. The per capita income for
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the town was $15,534. About 12.7% of families and 17.6% of the population were below the poverty
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line, including 23.7% of those under age 18 and 16.5% of those age 65 or over.
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History and settlement
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In 1820 the State of Maine was officially separated from Massachusetts, and at that time the name
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Bridgewater was applied to the Township. The area north of Bangor had been previously divided into
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6 mile square townships, and in 1803 the future Bridgewater Township was subdivided into two 3 mile
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x 6 mile areas, each designated a "grant" area to fund public academies in Portland and
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Bridgewater, respectively. The town of Bridgewater was incorporated on 2 March 1858.
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Notable people
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Jim Gerritsen, organic potato farmer and anti-GMO activist
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Colonel Frank M. Hume, commanding officer of the 103rd Infantry, 26th Division during World War I
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Colonel Gerald Evan Williams, World War II Air Force officer
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Sites of interest Bridgewater Town Hall and Jail References External links
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Towns in Aroostook County, Maine Towns in Maine
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In physics, the Fermi–Pasta–Ulam–Tsingou problem or formerly the Fermi–Pasta–Ulam problem was the
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apparent paradox in chaos theory that many complicated enough physical systems exhibited almost
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exactly periodic behavior – called Fermi–Pasta–Ulam–Tsingou recurrence (or Fermi–Pasta–Ulam
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recurrence) – instead of the expected ergodic behavior. This came as a surprise, as Fermi,
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certainly, expected the system to thermalize in a fairly short time. That is, it was expected for
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all vibrational modes to eventually appear with equal strength, as per the equipartition theorem,
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or, more generally, the ergodic hypothesis. Yet here was a system that appeared to evade the
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ergodic hypothesis. Although the recurrence is easily observed, it eventually became apparent that
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over much, much longer time periods, the system does eventually thermalize. Multiple competing
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theories have been proposed to explain the behavior of the system, and it remains a topic of active
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research.
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The original intent was to find a physics problem worthy of numerical simulation on the then-new
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MANIAC computer. Fermi felt that thermalization would pose such a challenge. As such, it represents
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one of the earliest uses of digital computers in mathematical research; simultaneously, the
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unexpected results launched the study of nonlinear systems.
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The FPUT experiment
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In the summer of 1953 Enrico Fermi, John Pasta, Stanislaw Ulam, and Mary Tsingou conducted computer
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simulations of a vibrating string that included a non-linear term (quadratic in one test, cubic in
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another, and a piecewise linear approximation to a cubic in a third). They found that the behavior
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of the system was quite different from what intuition would have led them to expect. Fermi thought
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that after many iterations, the system would exhibit thermalization, an ergodic behavior in which
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the influence of the initial modes of vibration fade and the system becomes more or less random
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with all modes excited more or less equally. Instead, the system exhibited a very complicated
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quasi-periodic behavior. They published their results in a Los Alamos technical report in 1955.
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(Enrico Fermi died in 1954, and so this technical report was published after Fermi's death.)
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In 2020, National Security Science magazine featured an article on Tsingou that included her
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commentary and historical reflections on the FPUT problem. In the article,Tsingou states “I
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remember sitting there one day with Pasta and Ulam,” as they brainstormed “some problems we could
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do on the computer, some really mathematical problems.” They tried several things, but, eventually,
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“they came up with this vibrating string.”
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The FPUT experiment was important both in showing the complexity of nonlinear system behavior and
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the value of computer simulation in analyzing systems.
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Name change
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The original paper names Fermi, Pasta, and Ulam as authors (although Fermi died before the report
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was written) with an acknowledgement to Tsingou for her work in programming the MANIAC simulations.
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Mary Tsingou's contributions to the FPUT problem were largely ignored by the community until
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published additional information regarding the development and called for the problem to be renamed
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to grant her attribution as well.
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The FPUT lattice system
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Fermi, Pasta, Ulam, and Tsingou simulated the vibrating string by solving the following discrete
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system of nearest-neighbor coupled oscillators. We follow the explanation as given in Richard
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Palais's article. Let there be N oscillators representing a string of length with equilibrium
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positions , where is the lattice spacing. Then the position of the j-th oscillator as a function
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of time is , so that gives the displacement from equilibrium. FPUT used the following equations of
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motion: