Sunday, July 31, 2011

The term “fossil fuel,” a linguistic relic from the time when anything dug from the earth was a fossil

The modern term “fossil fuel” is a linguistic relic from the sixteenth century and earlier times when any natural object or substance dug from underground was a fossil [1]. Famous for his masterpieces Opera Botanica (Work on Botanics) [2] and Historiae Animalium (History of Animals) [3], the naturalist Conrad Gesner (1516-1565) [4], with the latinized name Conradi Gesneri, published his book On Fossil Objects in 1565, in which the term “fossil” referred to any interesting object found in the ground [5].

In the seventeenth century, when the Dutch anatomist and geologist Nicolaus Steno formulated geologic principles on a scientific basis, the term “fossil” still had this broad meaning. But progress in geology, initiated in Steno's time, eventually changed the meaning to its modern use. Today the term “fossil” is typically confined to the preserved remains of ancient plants or animal life, including wood, bones, teeth and shells [1]. Fossil fuels are decomposition products of organisms living in the past. With recent progress in analytical chemistry and biochemistry, the word “fossil” is conquering nanoscience with terms such as “fossil molecule,” referring to chemical compounds originating from ancient life on earth  (see, for example, crenarchaeol, derived from crenarchaea).

Keynotes: fossils, paleontology, natural history, historical books, bibliophily.

References and more to explore
[1] Alan Cutler: The Seashell on the Mountaintop. Dutton (Penguin Group), New York, 2003; page 31.
[2] Conradi Gesneri: Opera botanica [].
[3] Virtually, turn the pages and see the illustrations in Conrad Gesner's Historiae Animalium [].
[4] Conrad Gesner Physician, Scholar, Scientist 1516-1565  [].
[5] History of Science: Konrad Gesner, posted Jan. 18, 2011:

Friday, July 29, 2011

New philosophy, natural philosophy, mechanical philosophy, experimental philosophy

New philosophy, natural philosophy, mechanical philosophy, experimental philosophy—these are all terms that describe the new science in the seventeenth century, when science did not exist in the form we know it today. Alan Cutler explains in his biography of the Dutch anatomist and geologist Nicolaus Steno, that during Steno's time most knowledge came from books [1]. Then, many universities confined learning to the writings of Aristotle and other scholars, did not encourage curiosity and kept students away from activities at which they might have dirtied their hands. Knowledge came from outside the academic walls [1]: “Potters learned about clay from the clay itself; miners and quarrymen learned about rocks from the rocks.” 

Steno was a great exception and ahead of his time: he dissected (for example, a shark head), observed and deduced to derive knowledge and principles, such as his principle of superposition; rather than just gleaning information from texts. Sixty years after Galileo Galilei triumphed over Aristotle and Ptolemy by observing stars and planets through telescopes and shaping modern physics (including astronomy), Steno's approach to earth science slowly was recognized by academic institutions and obscure societies, which were still clinging to superstition, scorcery and alchemy as their “state-of-the-art.” The new philosophy became visible at the horizon and the diverse terms for it eventually merged into the terms natural history, natural science or— simply and universally—science.

[1] Alan Cutler: The Seashell on the Mountaintop. Dutton (Penguin Group), New York, 2003; page 19.

Thursday, July 28, 2011

A term in geology: principle of superposition

The principle that in a series of stratified sedimentary rocks the lowest stratum is the oldest, is known in geology as the principle of superposition [1].Sometimes referred to as law of superposition, this principle is part of a set of three principles in stratigraphy, which were formulated in the seventeenth century by the Danish anatomist and geologist Nicolaus Steno. Steno's insight derived from his experience as an anatomist as well as his observations and knowledge of the growth of crystals, erosion of land and exposure of marine fossils in the mountains surrounding Florence,Tuscany.

The stratigraphic principle is a feature of the geologic field trip Principles of Historical Geology, which beautifully demonstrates these principles in an online slide-show file. My favorite narrative, explaining the superposition principle, is that given by Alan Cutler in his book The Seashell on the Mountaintop [2]:

The backbone of his [Steno's] system was a simple but tremendously powerful idea. Recognizing that the layers of rock that entombed fossil shells were made by the gradual accumulation of sediment, he realized that each layer embodied a span of time in the past. He saw no way to measure the number of years or centuries involved, and was loathe to speculate, but it was clear that the layers on top of the other formed an unambiguous sequence. The lowest layer had been formed first, the highest last. Depending on their fossils and their sediments, the layers recorded the succession of seas, rivers, lakes, and soils that once had covered the land. Geologists call Steno's insight the “principle of superposition.” It means that, layer by layer, the history of the world is written in stone.   

Cutler compares the significance of Steno's results with that of Galileo's breakthrough: while the latter opened up space by observation and discovery with a telescope, Steno provided an approach to study the past of planet earth—although only in relative terms of time until the invention of absolute dating methods such as techniques based on isotopes and radioactivity. 

[1] The Free Dictionary Thesaurus: principle of superposition [].
[2] Alan Cutler: The Seashell on the Mountaintop. Dutton (Penguin Group), New York, 2003; page 14.

Wednesday, July 27, 2011

Niels Stensen, following academic custom and going by the name Nicolai Stenonis

The Danish anatomist and geologist Niels Stensen started his career in the seventeenth century at the University of Copenhagen, where he followed academic custom and went by the name Nicolai Stenonis. Today he is known by the name Nicolaus Steno [1-3].

He was born in Copenhagen in January of 1638—Danemark was then at war with Sweden—and died in December of 1686 in Schwerin—today the capital of the German state Mecklenburg-Vorpommern. Most of his life, Steno worked, observed and researched at other places including Rostock, Amsterdam, Montpellier and Florence. In the book entitled The Seashell on the Mountaintop, Alan Cutler illuminates these locations in historical context, follows Steno's traveling and studies, and discusses his contributions to modern scientific thinking.

Steno had excellent observational skills, which he employed independently from what was known from books. Steno became a member of the Accademia del Cimento (Academy of Experiments) in Florence, Tuscany, funded by Prince Leopoldo and Grand Duke II de Medici. The academy welcomed Steno's ideas and his approach to science. Steno's findings in the hills and mountains surrounding Florence, rich in marine fossils, and his background in anatomy resulted in his celebrated formulation of the principles of stratigraphy: the law of superposition (layer-by-layer sedimentation), the principle of original horizontality and the principle of lateral continuity.

Steno was a darling of the Medici court, as Cutler writes in the prologue of his book. But today he is mostly overlooked: even visitors of the basilica of San Lorenzo in Florence, while admiring art work by Michelangelo and Brunelleschi, often miss the small chapel, where an inscription on the wall above the sacrophagus gives his name as Nicolai Stenonis. Tourists barely explore corners and layers beyond the authority of their travel guide.

Steno has been brought up in the Lutheran faith and later converted to Catholicism. Rare during his time as well as today, Steno had the ability to freely discuss scientific and religous topics without compromising one for the sake of the other.

References and suggested reading
[1] Alan Cutler: The Seashell on the Mountaintop. Dutton (Penguin Group), New York, 2003; page 18.
[2] Janice Busil: Nicolaus Steno: Getting to know the unheeded genius []
[3] Maria Hirsch: Urvater der modernen Geologie [Grandfather of modern geology] FOCUS Online, January 27, 2009. [].

Saturday, July 23, 2011

A term in chemistry and spintronics: half-metal for a material with an energy gap depending on electron spin direction

Metals differ from other chemical elements of the periodic table by their electrical and magnetic properties. A typical metal is characterized by good or excellent electrical conductivity, while the spins of the delocalized electrons in the lattice structure of the metal atoms are oriented without preference for a certain, singular direction. In contrast, a half-metal is only conducting when the spins of all electrons are aligned in one direction. It is insulating when their alignment is in opposite orientation. A half-metal is characterized by the presence of an energy gap at the Fermi level for only one electron spin direction, while the energy band for the opposite spin direction is continuous [1]. 

Half-metallic behavior is found in alloys and metal compounds. Examples include Heusler alloys (ferromagnetic alloys with a Heusler phase),  Fe3O4 (magnetite) and CrO2 [1-4].

Keywords: electronic materials, ferromagnetic materials, electrical conductivity, magnetoresistance

References and more to explore
[1] D. V. Talapin, J.-S. Lee, M. V. Kovalenko and E. V. Shevchenko: Prospects of Colloidal Nanocrystals for Electronic and Optoelectronic Applications. Chem. Rev. 2010, 110, 389-458. DOI: 10.1021/cr900137k; see page 410 for discussion of half-metals.
[2] I. Galanakis and Ph. Mavropoulos: Spin-polarization and electronic properties of half-metallic Heusler alloys calculated from first principle. J. Phys.: Condens. Matter 2007, 19, 315213 (16pp) [].
[3] J. Pierre and L. Ranno: Half Metallic Ferromagnets. Laboratoire Louis Neel, CNRS, Grenoble [].
[4] I. I. Mazin, D. J. Singh and C. Ambrosch-Draxl: Transport, optical, and electronic properties of the half-metal CrO2. Phys. Rev. B. 1999, 59, 411-418 []. 

Friday, July 22, 2011

Synonymous terms in chemistry and materials science: “conducting polymer” and “conjugated polymer”

Conducting polymers are often called conjugated polymers due to their macromolecular bond structure with alternating single and double bonds in the polymer chain: conducting polymers typically are organic materials possessing an extended conjugated π-electron system along a polymer backbone [1-3]. Such polymers become conducting polymers by providing unoccupied energy states for extra electrons or electron deficiencies (holes) and a macromolecular architecture for relatively unhindered charge carrier movement.

Polymeric materials with such structural characteristics are or are derived from, for example, polyacetylene, polypyrrole, polythiophene, polyaniline and poly(p-phenylene). Electrical properties and performance of conjugated-polymer materials can be enhanced by doping with either electron donors or electron acceptors. The doping process can also be employed to derive polymeric semiconductors (semiconducting polymers). Notice that the term “semiconjugated polymer” is not a synonym for “semiconducting polymer.”

Keywords: electronic materials, polymer chemistry, macromolecules, electrical conductivity

References and suggested reading
[1] Arno Kraft: Conducting Polymers; pages 341 to 377 in Organic Molecular Solids - Properties and Applications. Edited by William Jones, CRC Press, Boca Raton and New York, 1997.
[2] Steinke's Tutorial: Conducting Polymers [].
[3] Mohd Hamzah Harun, Elias Saion, Anuar Kassim, Noorhana Yahya and Ekramul Mahmud: Conjugated Conducting Polymers: A brief Overview. JASA 2, January 2007 [].

Sunday, July 10, 2011

Google's “+1” for “plus one” is fun

We know from arithmetics and computer science that  “+1” means “plus one.” The Google+ project now introduces the +1 button as a new tool to share your resources with your circle of friends and colleagues [1-3]. And as people—excuse me, friends and colleagues—are plusone-ing your sites, this may help improve the site ranking.

Plus one buttons are easy to implement (see Google +1 your website). Pages render fine when using the code provided by Google. I wasn't the only one, however, who experienced problems, while validating my HTML5 pages. After updating them with  +1 buttons and running them through the site, complaints were returned. So, a validation error for the g:plusone tag can be expected [4]. Then, I successfully replaced this XML element (for example, on the page with the following code:

<div class="g-plusone" data-count="true" data-size="medium">

Further information is available on the Google code site:

Keywords: HTML5 conformance, markup validation, social networking, professional networking, friend grouping, online sharing, bookmarking 

References and resources
[1] The Official Google Blog: Introducing the Google+ project: Real-life sharing, rethought for the web [].
[2] Google: Recommendations when you want them [].
[3] Digital inspiration: The Google Plus One Bookmarklet [].
[4] Pixelflips: Google +1 Button Validation Error []. 
[5] Drupal: Google Plus One HTML5 tag [].

Saturday, July 9, 2011

Acronym in microbiology and pathology: WNS for white-nose syndrome

WNS stands for white-nose syndrome, a fungal infection found in various bat species. The white-nose syndrome fungus (Geomyces destructans) affects hibernating bats in Europe and, more recently, also in North America [1]. The disease was discovered in early 2007, when bats in upstate New York started behaving oddly, flying far away from their caves during icy-cold winter days [2]. Infected bats typically show white patches of fungal growth around their muzzle, ears and wing membranes. There is evidence that American bats are less immunologically resistant to WNS than their European counterparts. G. destructans may have wiped out many bats in Europe in the distant past and today's survivors can withstand the fungus.

It is not known how the fungus kills the bat, but it has been proposed that mortality is caused by wing damage [3]. The USGS National Wildlife Health Center, in partnership with various research groups, plays a vital role in WNS research in the United States [4] .

References and more to explore
[1] Gudrun Wibbelt et al.: White-Nose Syndrome Fungus (Geomyces destructans) in Bats, Europe. Emerging Infectious Diseases August 2010, 16 (8), 1237-1242. [].
[2] Michelle Nijhuis: Crisis in the Caves. Smithsonian July/August 2011, 42 (4), 55-74. [].
[3] P. M. Cryan et al.: Wing pathology of white-nose syndrome in bats suggests life-threatening disruption of physiology. BMC Biology 2010, 8:135. DOI: 10.1186/1741-7007-8-135.
[4] National Wildlife Health Center: White-Nose Syndrome (WNS) [].

Monday, July 4, 2011

Ug99, a virulent strain of stem rust first identified in Uganda in 1999

Ug99 is a virulent and fast-mutating strain of stem rust, named after the location and year of its first identification: Uganda, 1999 [1-3]. The stem rust fungus, Puccinia graminis,  is spreading across the globe. It is a feared disease of wheat, known for centuries and causing significant losses of crop yield. The Ug99 strain spread from Uganda through other parts of Africa, including Kenya, Ethiopia and Sudan, crossed the Red Sea into Yemen and jumped the Persian Gulf into Iran.

How can the Ug99 threat be contained or eliminated? This depends on the success in developing a Ug99-specific fungicide (keeping up with the pace of mutations) or—probably a better solution—to find and grow resistant wheat varieties.

[1] Charles Siebert: Food Ark. National Geographic July 2011, 220 (1), 108-131. [].
[2] Ravi P. Singh et al.: Current status, likely migration and strategies to migrate the threat to wheat production from race Ug99 (TTKS) of stem rust pathogen. CAB Reviews: Perspective in Agriculture, Veterinary Science, Nutrition and Natural Resources 2006, 1 (054). [].
[3] Tiffany Stecker: Stem Rust Ug99 - Agricultural Bully, June 20, 2011 [].

Sunday, July 3, 2011

Ochroma pyramidale tree, commonly known as balsa tree

The tree species Ochroma pyramidale is a flowering plant of the mallow family (Malvaceae). Its common name is Balsa tree [1-3]. Ochroma descends from the Greek meaning pale and Balsa is a Spanish word meaning raft. Other common names (Bois flot, Corkwood, Down-Tree, West Indian balsa) and binomial synonyms (Bombax pyramidal, Ochroma bicolor, O. Concolor, O. grandiflora, O. lagopus, O. obtusum) are also in use [1].

Some of the synonyms indicate the cork-like structure of the Balsa wood and its floating-on-water behavior. Natalie Angier writes that Balsa has a fifth the density of water, cork a fourth, and only the papaya-related Jacaratia has lighter wood [3].

In her interesting article, illustrated with photographs by Christian Ziegler, Angier reports that scientist have long assumed that the night-flowering tree is pollinated by bats, which are nocturnal and, many of them, nectarivores [3]. But in addition the Balsa night life attracts all kinds of species including Capuchin monkeys, olingos (distant relative of the racoon),  opossums, geckos, honeybees, hummingbirds and snakes. While the snakes are looking for prey, most of the other arboreal guests act as pollinators by drinking the syrupy juice of the mature, cream-colored balsa flowers and then carrying pollen to the female parts of another balsa tree's flower. 

Ochromas are among the fastest growing tropical forest trees thriving from southern Mexico over Panama to Bolivia [3].

References and more to explore
[1] Jungle Garden - Hardy Tropical Plants: Ochroma pyramidale:
[2] Swartz: Ochroma pyramidale:
[3] Natalie Angier: Open all night. National Geographic May 2011, 219 (5), 130-143. [].