Willem Einthoven

from Wikipedia

Willem Einthoven (21 May 1860 – 29 September 1927) was a Dutch doctor and physiologist. He invented the first practical electrocardiogram (ECG or EKG) in 1903 and received the Nobel Prize in Medicine in 1924 for it.

BackgroundWillem_Einthoven_ECG

Einthoven was born in Semarang on Java in the Dutch East Indies (now Indonesia), the son of Louise Marie Mathilde Caroline (de Vogel) and Jacob Einthoven. His father, a doctor, died when Einthoven was a child. His mother returned to the Netherlands with her children in 1870 and settled in Utrecht. His father was of Jewish and Dutch descent, and his mother’s ancestry was Dutch and Swiss. In 1885, Einthoven received a medical degree from the University of Utrecht. He became a professor at the University of Leiden in 1886.

In 1902, he became member of the Royal Netherlands Academy of Arts and Sciences.

He died in Leiden in the Netherlands and is buried in the graveyard of the Reformed Church at 6 Haarlemmerstraatweg in Oegstgeest.
Work

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Occam’s razor

Taken From Wikipedia, the free encyclopedia on September 1, 2016

Andreas Cellarius’s illustration of the Copernican system, from the Harmonia Macrocosmica (1660). The motions of the sun, moon and other solar system planets can be calculated using a geocentric model (the earth is at the centre) or using a heliocentric model (the sun is at the centre). Both work, but the geocentric system requires many more assumptions than the heliocentric system, which has only seven. This was pointed out in a preface to Copernicus’ first edition of De revolutionibus orbium coelestium.

Occam’s razor (also written as Ockham’s razor, and lex parsimoniae in Latin, which means law of parsimony) is a problem-solving principle attributed to William of Ockham (c. 1287–1347), who was an English Franciscan friar, scholastic philosopher and theologian. The principle can be interpreted as stating Among competing hypotheses, the one with the fewest assumptions should be selected.

In science, Occam’s razor is used as a heuristic technique (discovery tool) to guide scientists in the development of theoretical models, rather than as an arbiter between published models. In the scientific method, Occam’s razor is not considered an irrefutable principle of logic or a scientific result; the preference for simplicity in the scientific method is based on the falsifiability criterion. For each accepted explanation of a phenomenon, there may be an extremely large, perhaps even incomprehensible, number of possible and more complex alternatives, because one can always burden failing explanations with ad hoc hypotheses to prevent them from being falsified; therefore, simpler theories are preferable to more complex ones because they are more testable.

Testing the razor

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Sick sinus syndrome

from the A.D.A.M. Medical Encyclopedia.

Sick sinus syndrome
Bradycardia-tachycardia syndrome; Sinus node dysfunction
Last reviewed: June 4, 2012.

Sick sinus syndrome is a collection of heart rhythm disorders that include:

  • Sinus bradycardia — slow heart rates from the natural pacemaker of the heart
  • Sinus pauses or arrest — when the natural pacemaker of the heart stops working for periods of time

People with these disorders may also have other abnormal heart rhythms, such as:

  • Atrial tachycardia — fast heart rate that starts in the upper chambers of the heart (atria)
  • Bradycardia-tachycardia — alternating slow and fast heart rhythms

Causes, incidence, and risk factors

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