mass transit

Examples of mass transit in the following topics:

• The Rise of the City

  • Skyscrapers were being built in the cities and the idea of mass transit had begun to take root.
  • Mass-transit systems allowed people to commute to work from farther distances.

• Monitoring Competition

  • Levitt argued, for example, that the passenger train industry made the mistake of restricting their competition to other railroads, instead of all mass transit transportation alternatives, including automobiles, airlines, and buses .
  • Levitt argued that the passenger train industry erred in restricting their competition to other railroads instead of all mass transit transportation alternatives, including automobiles, airlines, and buses.

• Automobiles, Airplanes, Mass Production, and Assembly-Line Progress

  • This was largely due to the adoption by industry of the technique of mass production, the system under which identical products were churned out quickly and inexpensively using assembly lines.
  • Before the war, cars were a luxury, but in the 1920s mass-produced vehicles became common throughout the country.
  • State government contracts to build highways and roads in rural areas increased as new housing sprung up outside the range of mass transit.
  • Radio became the first mass broadcasting medium during the 1920s.
  • Radio advertising became the grandstand for mass marketing and its economic importance led to the mass culture that has dominated society since.

• Biodiversity Change through Geological Time

  • The fossil record of the mass extinctions was the basis for defining periods of geological history, so they typically occur at the transition point between geological periods.
  • The transition in fossils from one period to another reflects the dramatic loss of species and the gradual origin of new species .
  • The transitions between the five main mass extinctions can be seen in the rock strata.
  • Sudden and dramatic losses of biodiversity, called mass extinctions, have occurred five times.
  • Describe how biodiversity has changed through geological time as a result of mass extinctions

• Molecular Excitations

  • On the other hand because the mass of the ions is much larger than that of the electrons we expect the wavefunction of the ions to be localized in a region $\sim a_0 m/M \ll a_0$.
  • We can get dipole transitions between the different rotational states if
  • We see that for the $R$ branch the transition energy decreases with increasing $Q$.
  • The Fortrat diagram (Figure 10.5) depicts the transition energies for various roto-vibrational transitions as a function of the rotational quantum number .
  • In general each vibration transition includes a rotational transition as well so one gets group of transitions.

• Population Trends

  • Most European nations are examples of countries at the end of the demographic transition: both birth and death rates are low, so populations are static or shrinking.
  • The demographic transition helps explain the differences between countries.
  • The demographic transition refers to the shift from high birth rates and death rates to low birth and death rates; this occurs as part of the economic development of a country.
  • Once the population exceeded the planet's carrying capacity, the population would be restrained through mass famine and starvation.
  • This model illustrates the demographic transition, as birth and death rates rise and fall but eventually reach equilibrium.

• Cleavage of the Zygote

  • From here, the spatial arrangement of blastomeres can follow various patterns, due to different planes of cleavage in various organisms.The end of cleavage is known as the midblastula transition and coincides with the onset of zygotic transcription.
  • The inner cell mass remains in contact with the trophoblast at one pole of the ovum.
  • Monozygotic twins can also develop from two inner cell masses.
  • A rare occurrence is the division of a single inner cells mass giving rise to twins.
  • However, if one inner cell mass divides incompletely, the result is conjoined twins.

• Energy, Mass, and Momentum of Photon

  • It has no rest mass and has no electric charge.
  • During a molecular, atomic or nuclear transition to a lower or higher energy level, photons of various energy will be emitted or absorbed respectively.
  • Momentum of photon: According to the theory of Special Relativity, energy and momentum (p) of a particle with rest mass m has the following relationship: $E^2 = (mc^2)^2+p^2c^2$, where c is the speed of light.
  • In the case of a photon with zero rest mass, we get $E = pc$.
  • You may wonder how an object with zero rest mass can have nonzero momentum.

• Heating Curve for Water

  • Water transitions from ice to liquid to water vapor as heat is added to it.
  • The amount of heat added, q, can be computed by: $q=m\cdot C_{H_2O(s)}\cdot \Delta T$ , where m is the mass of the sample of water, C is the specific heat capacity of solid water, or ice, and $\Delta T$ is the change in temperature during the process.
  • Instead, use the heat of fusion ($\Delta H_{fusion}$ ) to calculate how much heat was involved in that process: $q=m\cdot \Delta H_{fusion}$, where m is the mass of the sample of water.
  • At the atmospheric pressure of 1 atm, this phase transition occurs at 100o C (the normal boiling point of water).
  • Use the heat of vaporization ($\Delta H_{vap}$ ) to calculate how much heat was absorbed in this process: $q=m\cdot C_{H_2O(g)}\cdot \Delta T$, where m is the mass of the sample of water.

• Menopause

  • The transition from reproductive to non-reproductive is the result of a reduction in female hormonal production by the ovaries.
  • This transition is normally not sudden or abrupt, tends to occur over a period of years, and is a natural consequence of aging.
  • The only sign or effect that all women universally have in common is that by the end of the menopause transition every woman will have a complete cessation of menses.
  • An early menopause can be related to cigarette smoking, higher body mass index, racial and ethnic factors, illnesses, chemotherapy, radiation and the surgical removal of the uterus and/or both ovaries.
  • Signs and effects of the menopause transition can begin as early as age 35, although most women become aware of the transition in their mid to late 40's, often many years after the actual beginning of the perimenopausal window.