The world’s first wiki where authorship really matters Nature Genetics, Due credit and reputation for authors. Imagine a global collaborative knowledge base for original thoughts. Search thousands of articles and collaborate with scientists around the globe. Hoffmann, R. A wiki for the life sciences where authorship matters. Nature Genetics Share Send to a friend Share. Personal info Your homepage Your articles Create article. View Font size Color scheme.
This work is licensed under a Creative Commons Attribution 4. This book is intended for intermediate readers. A printable version of Planet Earth is available. For a single panel print version to print out. Every moment of your life will be from the perspective of a single planet— Planet Earth. You were born here and you will die here.
BioTek White Papers, Jun, An Introduction to Fluorescence Resonance Energy Transfer (FRET) Technology and its Application in Bioscience.
Located 10 minutes north of Augusta, Jewel Cave is the largest show cave in Western Australia and also the most recently developed. It is named after the Jewel Casket, a small chamber in the lower sections of the cave. The cave was opened to the public on the 26th December Cliff was lowered into the cave during January Descending 12 metres through a solution pipe into a large chamber he reached a soil cone another 8 metres below the ceiling.
The cave has a depth of 42 metres, with the floor being approximately 24 metres above sea level. Jewel Cave is located in a limestone area approximately 90 kilometres long and 3 kilometres wide known as the Leeuwin-Naturaliste Ridge. The limestone Aeolian calcarenite , which forms the Leeuwin- Naturaliste Ridge was formed from coastal sand dunes when westerly winds along our coastline blew beach sand, sea-shells and corals into huge sand dunes during the last million years.
Humboldt W. Leverenz, a specialist in materials used in electrical technologies, graduated from Stanford University in with a degree in chemistry. He received the Franklin Institute Brown Medal in for his contributions to the development of the fluorescent lamp. The main focus of his research at this time was developing luminescent materials for development of an all-electronic television.
Leverenz’s development of zinc beryllium silicate manganese was a major contribution to the development of practical fluorescent lamps. He eventually shifted his research to sulfur-dominated materials.
Traps MQ Luminescence Dating Facility, Department of Environmental Sciences, Macquarie
Phosphorescence is a specific type of photoluminescence related to fluorescence. Unlike fluorescence, a phosphorescent material does not immediately re-emit the radiation it absorbs. The slower time scales of the re-emission are associated with “forbidden” energy state transitions in quantum mechanics. As these transitions occur less often in certain materials, absorbed radiation may be re-emitted at a lower intensity for up to several hours.
In simpler terms, phosphorescence is a process in which energy absorbed by a substance is released relatively slowly in the form of light. This is in some cases the mechanism used for “glow-in-the-dark” materials which are “charged” by exposure to light. Unlike the relatively swift reactions in a common fluorescent tube, phosphorescent materials used for these materials absorb the energy and “store” it for a longer time as the subatomic reactions required to re-emit the light occur less often.
Most photoluminescent events, in which a chemical substrate absorbs and then re-emits a photon of light, are fast, on the order of 10 nanoseconds. However, for light to be absorbed and emitted at these fast time scales, the energy of the photons involved i. In the special case of phosphorescence, the absorbed photon energy undergoes an unusual intersystem crossing into an energy state of higher spin multiplicity see term symbol , usually a triplet state. As a result, the energy can become trapped in the triplet state with only quantum mechanically “forbidden” transitions available to return to the lower energy state.
These transitions, although “forbidden”, will still occur but are kinetically unfavored and thus progress at significantly slower time scales. Most phosphorescent compounds are still relatively fast emitters, with triplet lifetimes on the order of milliseconds. However, some compounds have triplet lifetimes up to minutes or even hours, allowing these substances to effectively store light energy in the form of very slowly degrading excited electron states.
Objectives To examine indexed health science journals to evaluate the prevalence of Wikipedia citations, identify the journals that publish articles with Wikipedia citations, and determine how Wikipedia is being cited. Study selection Publications in the English language that included citations to Wikipedia were retrieved using the online databases Scopus and Web of Science.
Using Thomson Reuters Journal Citation Reports, impact factors were collected for all journals included in the search. Data extraction Resulting citations were thematically coded, and descriptive statistics were calculated.
Phosphorescence is a specific type of photoluminescence related to fluorescence. Unlike fluorescence, a phosphorescent material does not immediately re-emit.
The discovery of green fluorescent protein in the early s ultimately heralded a new era in cell biology by enabling investigators to apply molecular cloning methods, fusing the fluorophore moiety to a wide variety of protein and enzyme targets, in order to monitor cellular processes in living systems using optical microscopy and related methodology. When coupled to recent technical advances in widefield fluorescence and confocal microscopy, including ultrafast low light level digital cameras and multitracking laser control systems, the green fluorescent protein and its color-shifted genetic derivatives have demonstrated invaluable service in many thousands of live-cell imaging experiments.
Osamu Shimomura and Frank Johnson, working at the Friday Harbor Laboratories of the University of Washington in , first isolated a calcium-dependent bioluminescent protein from the Aequorea victoria jellyfish, which they named aequorin. During the isolation procedure, a second protein was observed that lacked the blue-emitting bioluminescent properties of aequorin, but was able to produce green fluorescence when illuminated with ultraviolet light.
Due to this property, the protein was eventually christened with the unceremonious name of green fluorescent protein GFP. Over the next two decades, researchers determined that aequorin and the green fluorescent protein work together in the light organs of the jellyfish to convert calcium-induced luminescent signals into the green fluorescence characteristic of the species.
Although the gene for green fluorescent protein was first cloned in , the significant potential as a molecular probe was not realized until several years later when fusion products were used to track gene expression in bacteria and nematodes. Since these early studies, green fluorescent protein has been engineered to produce a vast number of variously colored mutants, fusion proteins, and biosensors that are broadly referred to as fluorescent proteins.
More recently, fluorescent proteins from other species have been identified and isolated, resulting in further expansion of the color palette.
Continue to access RSC content when you are not at your institution. Follow our step-by-step guide. The general design principle for developing luminescent redox indicators based on photoinduced electron transfer is described. The first part of the review introduces colorimetric and fluorimetric redox indicators.
Radiometric dating is a technique used to date materials based on a knowledge of the decay rates of naturally occurring isotopes , and the current abundances. It is our principal source of information about the age of the Earth and a significant source of information about rates of evolutionary change. All ordinary matter is made up of combinations of chemical elements , each with its own atomic number , indicating the number of protons in the atomic nucleus.
Additionally, elements may exist in different isotopes , with each isotope of an element differing only in the number of neutrons in the nucleus. A particular isotope of a particular element is called a nuclide. Some nuclides are inherently unstable. That is, at some random point in time, an atom of such a nuclide will be transformed into a different nuclide by the process known as radioactive decay.
Optically-Stimulated Luminescence is a late Quaternary dating technique used to date the last time quartz sediment was exposed to light. As sediment is transported by wind, water, or ice, it is exposed to sunlight and zeroed of any previous luminescence signal. Once this sediment is deposited and subsequently buried, it is removed from light and is exposed to low levels of natural radiation in the surrounding sediment.
DigAR Lab · Geoarchaeology Lab · Luminescence Dating Laboratory · Microanalysis Lab · Biological Anthropology Labs» · Biodemography Laboratory.
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The treatments, methods, or techniques described herein are provided for informational purposes. The reader assumes responsibility for any application results. Examination and Documentation are part of the process of conservation of an object for documenting condition before, during and after treatment as well as tools for assessment. Standardized documentation and examination techniques are used by conservators as part of their practice in accordance with AIC’s Code of Ethics that states in article VII: “The Conservation Professional shall document examination, scientific investigation and treatment by creating permanent records and reports”.
Documentation techniques have to follow strict rules of consistency and accuracy.
 Lumenescence dating. Wikipedia. Luminescence_dating.  C.K. Ross, N.V. Klassen, Water calorimetry for radiation dosimetry.
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