... depicting the wavelengths of electromagnetic radiation
absorbed by a material, usually a gas . It can ... white light, which consists of electromagnetic radiation
at all frequencies, passing through a sample of ... in the direction in which the electromagnetic radiation
was originally travelling. If the material is a ...
... Adaptive radiation
describes the rapid speciation of a single or ... by mutation and natural selection .
often occurs when a species is introduced to a ... 300 million years ago.
The dynamics of adaptive radiation
is such that, within a relatively short time, ...
4.4 Clinical trials
4.5 ... can be treated by surgery , chemotherapy , radiation
therapy or other methods. The choice of therapy ... regimens are given in a combination.
Fick's law of diffusion
... D .
Fick's first law is also important in radiation
transfer equations. However, in this context it ... when the diffusion constant is low and the radiation
becomes limited by the speed of light rather than by the resistance of the material the radiation
is flowing through. In this situation, one can ...
Magnetic resonance imaging
2.2.5 Interventional MRI
2.2.7 Current Density ... patients from associating the examination with radiation
exposure. Scientists still use NMR when ... utilizes strong magnetic fields and non-ionizing radiation
in the radio frequency range. Compare this to CT ...
... are the building blocks of electromagnetic radiation
: that is, a photon is a "particle" of light , ... that is, the smallest amount of electromagnetic radiation
that can exist is one photon whatever its ... light in thermal equilibrium ( black-body radiation
The associated quantum state is the Fock ...
... the faeces and urine, respiration, conduction and radiation
from the skin, and by evaporation of ... about 3, respiration about 20, skin (conduction, radiation
and evaporation) about 77. Hence it is clear the ... by cooling blood vessels in the dermis.
- e.g. acquisition of heat from ...
Computed axial tomography
... +1000 HU.
Improvements in CT technology have meant that the overall radiation
dose has decreased, scan times have decreased and the ability to ... same location from a different angle) has increased over time. Still, the radiation
dose from CT scans is several times higher than conventional X-ray ...
... field or magnetic field , or in any volume containing electromagnetic radiation
. The SI unit of electrical energy is the joule , while the unit used ... and inductors, or the fields propagating in space as electromagnetic radiation
. The amount of electrical energy surrounding a conductor or travelling ...
... An autoradiograph is an image produced on a photographic film by the radiation
from a radioactive substance.
... extinction is dependent on an accurate and complete catalogue of plants provided systematics and taxonomy .
Plant responses to ultraviolet radiation
can help us monitor problems like the holes in the ozone layer .
Analysing pollen deposited by plants thousands or millions of years ago can ...
... The bag is heated to body temperature, to avoid causing cramping. Dry heat is used; common methods include microwaves , heating pads and solar radiation
(often using the dashboard of a car, for instance while travelling).
The patient, who performs the entire procedure themselves, dons a disposable ...
3 See also
4 External links
Diffusion is one kind of transport phenomenon : compare it, for example, to radiation
. All diffusion can be modelled quantitatively using the diffusion equation , the solutions of which go by different names depending on the ...
... environment. Cold-blooded animals are often referred to as ectotherms .
Ectotherms depend largely on external sources of heat, such as solar radiation
. As the environmental temperature increases, the animal's metabolic rate will increase. Lizards, fish, and amphibians are examples of ...
... (usually DNA or RNA ) of a cell , and can be caused by "copying errors" in the genetic material during cell division and by exposure to radiation
, chemicals, or viruses , or can occur deliberately under cellular control during processes such as meiosis or hypermutation . In multicellular ...
... in space has been very sporadic, with a maximum of thirteen humans in space at any given time, in part because of human vulnerability to ionizing radiation
, starting with Yuri Gagarin 's space flight in 1961 . Between 1969 and 1974 , up to two humans at a time spent brief intervals on the Moon . ...
... Immunotherapy is most commonly used in the context of the treatment of cancers together with chemotherapy ( drugs ) and radiotherapy ( radiation
). However, immunotherapy is also often used in the immunosuppressed (such as HIV patients) and people suffering from other immune deficiencies or ...
... were switched on in some women.
The hypothesis was first stated by Mary F. Lyon in 1961 while she was studying the genetic consequences of radiation
exposure, and therefore bears her name .
XY sex-determination system
Carrel L, ...
... known as extremophiles . Some extremophiles have been known to survive for a prolonged time in a vacuum , and some can be unusually resistant to radiation
Microorganisms are used in brewing , baking , biotechnology , recycling of other organisms' remains and waste products, and many other ...
... (usually DNA or RNA ) of a cell . Mutations can be caused by copying errors in the genetic material during cell division and by exposure to radiation
, chemicals, or viruses , or can occur deliberately under cellular control during the processes such as meiosis or hypermutation . Mutations are ...
... ) of an organism and thus increases the number of mutations above the natural background level.
Mutagens are usually chemical compounds or radiation
The Ames test is one method to determine how mutagenic an agent is.
... organisms . The field encompasses many biological phenomena, including photosynthesis , visual processing , circadian rhythms , and ultraviolet radiation
effects. There are numerous professional societies devoted to the study of photobiology, the largest of which are the American Society for ...
... The prion hypothesis was developed to explain why the mysterious infectious agent causing Creutzfeldt-Jakob disease resisted ultraviolet radiation
(which breaks down nucleic acids), yet responded to agents that disrupt proteins. Initially, this hypothesis was highly controversial, because it ...
... the independent proposals of the theory of evolution by natural selection of Patrick Matthew and Alfred Russel Wallace .
See also: Adaptive radiation
Eldredge, Niles, and Gould, Stephen Jay:"Punctuated equilibria: an alternative to phyletic gradualism" in: T.Schopf (Hrsg.), ...
... and excretion (through sweat ).
Skin on creatures regularly subjected to sunlight have pigmentation which absorbs the potentially dangerous radiation
contained therein. Human skin pigmentation varies across populations in a visually dramatic manner. This has sometimes led to the classification of ...
... drastic changes (called "saltation") that result in speciation in a very short time. Speciation is also related to a process known as adaptive radiation
Ernst Mayr proposed a speciation mechanism called allopatry . Allopatry begins when subpopulations of a species ...
... through the Earth 's atmosphere (although blue light is scattered more than red light, which is the reason the sky is blue). Electromagnetic radiation
outside the optical wavelength range is almost entirely absorbed by the atmosphere.
... point in a given time. The wavelength is equal to the speed of the wave type divided by the frequency of the wave. When dealing with electromagnetic radiation
in a vacuum, this speed is the speed of light c , for signals (waves) in air, this is the speed of sound in air. The relationship is given by:
... macromolecules such as protein and DNA complexes. The crystals are harvested and often frozen with liquid nitrogen . Freezing crystals both reduces radiation
damage incurred during data collection and decreases thermal motion within the crystal. Crystals are placed on a diffractometer , a machine that ...