Lights flash at frequency f = 0.5 Hz (Hz = hertz), 1.0 Hz and 2.0 Hz, where Failed to parse (Missing texvc executable; please see math/README to configure.): x

Hz means Failed to parse (Missing texvc executable; please see math/README to configure.): x
flashes per second. T is the period and T = Failed to parse (Missing texvc executable; please see math/README to configure.): y
s (s = second) means that Failed to parse (Missing texvc executable; please see math/README to configure.): y

is the number of seconds per flash. T and f are each other's reciprocal: f = 1/T and T = 1/f.

The hertz (symbol Hz) is the SI unit of frequency defined as the number of cycles per second of a periodic phenomenon.^[1] One of its most common uses is the description of the sine wave, particularly those used in radio and audio applications. The word "hertz" is named for Heinrich Rudolf Hertz, who was the first to conclusively prove the existence of electromagnetic waves.

Definition[link]

The hertz is equivalent to cycles per second.^[2] In defining the second, the CIPM declared that "the standard to be employed is the transition between the hyperfine levels F = 4, M =  0 and F = 3, M = 0 of the ground state 2S_1/2 of the cesium 133 atom, unperturbed by external fields, and that the frequency of this transition is assigned the value 9 192 631 770 hertz"^[3] thereby effectively defining the hertz and the second simultaneously.

In English, hertz is used as a plural.^[4] As an SI unit, Hz can be prefixed; commonly used multiples are kHz (kilohertz, 10³ Hz), MHz (megahertz, 10⁶ Hz), GHz (gigahertz, 10⁹ Hz) and THz (terahertz, 10¹² Hz). One hertz simply means "one cycle per second" (typically that which is being counted is a complete cycle); 100 Hz means "one hundred cycles per second", and so on. The unit may be applied to any periodic event—for example, a clock might be said to tick at 1 Hz, or a human heart might be said to beat at 1.2 Hz. The "frequency" (activity) of aperiodic or stochastic events, such as radioactive decay, is expressed in becquerels.

Even though angular velocity, angular frequency and hertz all have the dimensions of 1/s, angular velocity and angular frequency are not expressed in hertz,^[5] but rather in an appropriate angular unit such as radians per second. Thus a disc rotating at 60 revolutions per minute (rpm) is said to be rotating at either 2π rad/s or 1 Hz, where the former measures the angular velocity and the latter reflects the number of complete revolutions per second. The conversion between a frequency f measured in hertz and an angular velocity ω measured in radians per second are:

Failed to parse (Missing texvc executable; please see math/README to configure.): \omega = 2\pi f \,

and Failed to parse (Missing texvc executable; please see math/README to configure.): f = \frac{\omega}{2\pi} \, 

. This SI unit is named after Heinrich Hertz. As with every International System of Units (SI) unit whose name is derived from the proper name of a person, the first letter of its symbol is upper case (Hz). When an SI unit is spelled out in English, it should always begin with a lower case letter (hertz), except where any word would be capitalized, such as at the beginning of a sentence or in capitalized material such as a title. Note that "degree Celsius" conforms to this rule because the "d" is lowercase. —Based on The International System of Units, section 5.2.

History[link]

The hertz is named after the German physicist Heinrich Hertz who made important scientific contributions to the study of electromagnetism. The name was established by the International Electrotechnical Commission (IEC) in 1930.^[6] It was adopted by the General Conference on Weights and Measures (CGPM) (Conférence générale des poids et mesures) in 1960, replacing the previous name for the unit, cycles per second (cps), along with its related multiples, primarily kilocycles per second (kc/s) and megacycles per second (Mc/s), and occasionally kilomegacycles per second (kMc/s). The term cycles per second was largely replaced by hertz by the 1970s.

The term "gigahertz", most commonly used in computer processor clock rates and radio frequency (RF) applications, can be pronounced either /ˈɡɪɡəhɜrts/, with a hard /ɡ/ sound, or /ˈdʒɪɡəhɜrts/, with a soft /dʒ/^[7] (see giga-#Pronunciation). The prefix "giga-" is derived directly from the Greek "γιγας" ("giant").

Applications[link]

Sine waves of different frequency.

Details of a heartbeat as an example of a non-sinusoidal periodic phenomenon that can be described in terms of hertz. Two complete cycles are illustrated.

Vibration[link]

Sound is a traveling wave which is an oscillation of pressure. Humans perceive frequency of sound waves as pitch. Each musical note corresponds to a particular frequency which can be measured in hertz. An infant's ear is able to perceive frequencies ranging from 20 Hz to 20,000 Hz; the average adult human can hear sounds between 20 Hz and 16,000 Hz.^[8] The range of ultrasound, high-intensity infrasound and other physical vibrations such as molecular vibrations extends into the megahertz range and well beyond.

Electromagnetic radiation[link]

Electromagnetic radiation is often described by its frequency—the number of oscillations of the perpendicular electric and magnetic fields per second—expressed in hertz.

Radio frequency radiation is usually measured in kilohertz (kHz), megahertz (MHz), or gigahertz (GHz). Light is electromagnetic radiation that is even higher in frequency, and has frequencies in the range of tens (infrared) to thousands (ultraviolet) of terahertz. Electromagnetic radiation with frequencies in the low terahertz range, (intermediate between those of the highest normally usable radio frequencies and long-wave infrared light), is often called terahertz radiation. Even higher frequencies exist, such as that of gamma rays, which can be measured in exahertz. (For historical reasons, the frequencies of light and higher frequency electromagnetic radiation are more commonly specified in terms of their wavelengths or photon energies: for a more detailed treatment of this and the above frequency ranges, see electromagnetic spectrum.)

Computing[link]

In computing, most central processing units (CPU) are labeled in terms of their clock rate expressed in megahertz or gigahertz (10⁶ or 10⁹ hertz, respectively). This number refers to the frequency of the CPU's master clock signal ("clock rate"). This signal is simply an electrical voltage which changes from low to high and back again at regular intervals. This signal is a square wave. Hertz has become the primary unit of measurement accepted by the general populace to determine the performance of a CPU, but many experts have criticized this approach, which they claim is an easily manipulable benchmark.^[9] For home-based personal computers, the CPU has ranged from approximately 1 megahertz in the late 1970s (Atari, Commodore, Apple computers) to up to 6 GHz in the present (IBM POWER processors) and up to 8 GHz overclocked (AMD FX processors).^[10]

Various computer buses, such as the front-side bus connecting the CPU and northbridge, also operate at different frequencies in the megahertz range

[edit] SI multiples

Frequencies not expressed in hertz[link]

Even higher frequencies are believed to occur naturally, in the frequencies of the quantum-mechanical wave functions of high-energy (or, equivalently, massive) particles, although these are not directly observable, and must be inferred from their interactions with other phenomena. For practical reasons, these are typically not expressed in hertz, but in terms of the equivalent quantum energy, which is proportional to the frequency by the factor of Planck's constant.

See also[link]

References[link]

External links[link]

• BIPM Cesium ion f_Cs definition
• National Research Council of Canada: Generation of the Hz
• National Research Council of Canada: Cesium fountain clock
• National Physical Laboratory: Trapped ion optical frequency standards
• National Research Council of Canada: Optical frequency standard based on a single trapped ion
• National Research Council of Canada: Optical frequency comb
• One Hertz in Radians per Second (Google). Note, as of 06 May 2009 there is an error of 2Failed to parse (Missing texvc executable; please see math/README to configure.): \pi

.

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Heinrich Hertz
Born	Heinrich Rudolf Hertz (1857-02-22)22 February 1857 Hamburg, German Confederation
Died	1 January 1894(1894-01-01) (aged 36) Bonn, German Empire
Residence	Germany
Nationality	German
Fields	Physics Electronic Engineering
Institutions	University of Kiel University of Karlsruhe University of Bonn
Alma mater	University of Munich University of Berlin
Doctoral advisor	Hermann von Helmholtz
Known for	Electromagnetic radiation Photoelectric effect
Signature

Heinrich Rudolf Hertz (22 February 1857 – 1 January 1894) was a German physicist who clarified and expanded James Clerk Maxwell's electromagnetic theory of light, which was first demonstrated by David Edward Hughes using non-rigorous trial and error procedures. Hertz is distinguished from Maxwell and Hughes because he was the first to conclusively prove the existence of electromagnetic waves by engineering instruments to transmit and receive radio pulses using experimental procedures that ruled out all other known wireless phenomena.^[1] The scientific unit of frequency — cycles per second — was named the "hertz" in his honor.^[2]

Life and career[link]

Early years[link]

Hertz was born in Hamburg, then a sovereign state of the German Confederation, into a prosperous and cultured Hanseatic family. His father, David Gustav Hertz, was a writer and later a senator. His mother was the former Anna Elisabeth Pfefferkorn. His paternal great-grandfather, David Wolff Hertz (1757–1822), fourth son of Benjamin Wolff Hertz, moved to Hamburg in 1793, where he made his living as a jeweller; he and his wife Schöne Hertz (1760–1834) were buried in the former Jewish cemetery in Ottensen. Their first son, Wolff Hertz (1790–1859), was chairman of the Jewish community. Hertz' paternal grandfather, Heinrich David Hertz (1797–1862), was a respected businessman, and his paternal grandmother, Betty Oppenheim, was the daughter of the banker Salomon Oppenheim, from Cologne. Hertz's father and paternal grandparents converted from Judaism to Christianity.^[3][4] His mother's family was Lutheran.^[5]

While studying at the Gelehrtenschule des Johanneums in Hamburg, he showed an aptitude for sciences as well as languages, learning Arabic and Sanskrit. He studied sciences and engineering in the German cities of Dresden, Munich and Berlin, where he studied under Gustav R. Kirchhoff and Hermann von Helmholtz.

In 1880, Hertz obtained his PhD from the University of Berlin; and remained for post-doctoral study under Hermann von Helmholtz.

In 1883, Hertz took a post as a lecturer in theoretical physics at the University of Kiel.

In 1885, Hertz became a full professor at the University of Karlsruhe where he discovered electromagnetic waves.

The most dramatic prediction of Maxwell's theory of electromagnetism, published in 1865, was the existence of electromagnetic waves moving at the speed of light, and the conclusion that light itself was just such a wave. This challenged experimentalists to generate and detect electromagnetic radiation using some form of electrical apparatus.

The first successful radio transmission was made by David Edward Hughes in 1879, but it would not be conclusively proven to have been electromagnetic waves until the experiments of Heinrich Hertz in 1886. For the Hertz radio wave transmitter, he used a high voltage induction coil, a condenser (capacitor, Leyden jar) and a spark gap—whose poles on either side are formed by spheres of 2 cm radius—to cause a spark discharge between the spark gap’s poles oscillating at a frequency determined by the values of the capacitor and the induction coil.

To prove there really was radiation emitted, it had to be detected. Hertz used a piece of copper wire, 1 mm thick, bent into a circle of a diameter of 7.5 cm, with a small brass sphere on one end, and the other end of the wire was pointed, with the point near the sphere. He bought a screw mechanism so that the point could be moved very close to the sphere in a controlled fashion. This "receiver" was designed so that current oscillating back and forth in the wire would have a natural period close to that of the "transmitter" described above. The presence of oscillating charge in the receiver would be signaled by sparks across the (tiny) gap between the point and the sphere (typically, this gap was hundredths of a millimeter).

In more advanced experiments, Hertz measured the velocity of electromagnetic radiation and found it to be the same as the light’s velocity. He also showed that the nature of radio waves’ reflection and refraction was the same as those of light and established beyond any doubt that light is a form of electromagnetic radiation obeying the Maxwell equations.

Hertz's experiments triggered broad interest in radio research that eventually produced commercially successful wireless telegraph, audio radio, and later television. In 1930 the International Electrotechnical Commission (IEC) honored Hertz by naming the unit of frequency—one cycle per second—the "hertz".^[2]

Meteorology[link]

He always had a deep interest in meteorology probably derived from his contacts with Wilhelm von Bezold (who was Hertz's professor in a laboratory course at the Munich Polytechnic in the summer of 1878). Hertz, however, did not contribute much to the field himself except some early articles as an assistant to Helmholtz in Berlin, including research on the evaporation of liquids, a new kind of hygrometer, and a graphical means of determining the properties of moist air when subjected to adiabatic changes.^[6]

Contact mechanics[link]

Memorial of Heinrich Hertz on the campus of the Karlsruhe Institute of Technology

In 1886–1889, Hertz published two articles on what was to become known as the field of contact mechanics. Hertz is well known for his contributions to the field of electrodynamics (see below); however, most papers that look into the fundamental nature of contact cite his two papers as a source for some important ideas. Joseph Valentin Boussinesq published some critically important observations on Hertz's work, nevertheless establishing this work on contact mechanics to be of immense importance. His work basically summarises how two axi-symmetric objects placed in contact will behave under loading, he obtained results based upon the classical theory of elasticity and continuum mechanics. The most significant failure of his theory was the neglect of any nature of adhesion between the two solids, which proves to be important as the materials composing the solids start to assume high elasticity. It was natural to neglect adhesion in that age as there were no experimental methods of testing for it.

To develop his theory Hertz used his observation of elliptical Newton's rings formed upon placing a glass sphere upon a lens as the basis of assuming that the pressure exerted by the sphere follows an elliptical distribution. He used the formation of Newton's rings again while validating his theory with experiments in calculating the displacement which the sphere has into the lens. K. L. Johnson, K. Kendall and A. D. Roberts (JKR) used this theory as a basis while calculating the theoretical displacement or indentation depth in the presence of adhesion in their landmark article "Surface energy and contact of elastic solids" published in 1971 in the Proceedings of the Royal Society (A324, 1558, 301–313). Hertz's theory is recovered from their formulation if the adhesion of the materials is assumed to be zero. Similar to this theory, however using different assumptions, B. V. Derjaguin, V. M. Muller and Y. P. Toporov published another theory in 1975, which came to be known as the DMT theory in the research community, which also recovered Hertz's formulations under the assumption of zero adhesion. This DMT theory proved to be rather premature and needed several revisions before it came to be accepted as another material contact theory in addition to the JKR theory. Both the DMT and the JKR theories form the basis of contact mechanics upon which all transition contact models are based and used in material parameter prediction in nanoindentation and atomic force microscopy. So Hertz's research from his days as a lecturer, preceding his great work on electromagnetism, which he himself considered with his characteristic soberness to be trivial, has come down to the age of nanotechnology.

Electromagnetic research[link]

Official English translation of Untersuchungen über die Ausbreitung der elektrischen Kraft published in 1893, a year before Hertz's death.

Theoretical results from the 1887 experiment

In 1886, Hertz developed the Hertz antenna receiver. This is a set of terminals which is not electrically grounded for its operation. He also developed a transmitting type of dipole antenna, which was a center-fed driven element for transmitting UHF radio waves. These antennas are the simplest practical antennas from a theoretical point of view.

In 1887, Hertz experimented with radio waves in his laboratory. These actions followed Michelson's 1881 experiment (precursor to the 1887 Michelson–Morley experiment), which did not detect the existence of aether drift. Hertz altered Maxwell's equations to take this view into account for electromagnetism. Hertz used a Ruhmkorff coil-driven spark gap and one meter wire pair as a radiator. Capacity spheres were present at the ends for circuit resonance adjustments. His receiver, a precursor to the dipole antenna, was a simple half-wave dipole antenna for shortwaves. Hertz published his work in a book titled: Electric waves: being researches on the propagation of electric action with finite velocity through space.^[7]

Through experimentation, he proved that transverse free space electromagnetic waves can travel over some distance. This had been predicted by James Clerk Maxwell and Michael Faraday. With his apparatus configuration, the electric and magnetic fields would radiate away from the wires as transverse waves. Hertz had positioned the oscillator about 12 meters from a zinc reflecting plate to produce standing waves. Each wave was about 4 meters. Using the ring detector, he recorded how the magnitude and wave's component direction vary. Hertz measured Maxwell's waves and demonstrated that the velocity of radio waves was equal to the velocity of light. The electric field intensity and polarity was also measured by Hertz. (Hertz, 1887, 1888).

The Hertzian cone was first described by Hertz as a type of wave-front propagation through various media. His experiments expanded the field of electromagnetic transmission and his apparatus was developed further by others in the radio. Hertz also found that radio waves could be transmitted through different types of materials, and were reflected by others, leading in the distant future to radar.

Hertz helped establish the photoelectric effect (which was later explained by Albert Einstein) when he noticed that a charged object loses its charge more readily when illuminated by ultraviolet light. In 1887, he made observations of the photoelectric effect and of the production and reception of electromagnetic (EM) waves, published in the journal Annalen der Physik. His receiver consisted of a coil with a spark gap, whereby a spark would be seen upon detection of EM waves. He placed the apparatus in a darkened box to see the spark better. He observed that the maximum spark length was reduced when in the box. A glass panel placed between the source of EM waves and the receiver absorbed ultraviolet radiation that assisted the electrons in jumping across the gap. When removed, the spark length would increase. He observed no decrease in spark length when he substituted quartz for glass, as quartz does not absorb UV radiation. Hertz concluded his months of investigation and reported the results obtained. He did not further pursue investigation of this effect, nor did he make any attempt at explaining how the observed phenomenon was brought about.

Hertz did not realize the practical importance of his experiments. He stated that,

"It's of no use whatsoever[...] this is just an experiment that proves Maestro Maxwell was right—we just have these mysterious electromagnetic waves that we cannot see with the naked eye. But they are there."^[8][9][10]

Asked about the ramifications of his discoveries, Hertz replied,

"Nothing, I guess."^[8]

His discoveries would later be more fully understood by others and be part of the new "wireless age". In bulk, Hertz' experiments explain reflection, refraction, polarization, interference, and velocity of electric waves.

In 1892, Hertz began experimenting and demonstrated that cathode rays could penetrate very thin metal foil (such as aluminium). Philipp Lenard, a student of Heinrich Hertz, further researched this "ray effect". He developed a version of the cathode tube and studied the penetration by X-rays of various materials. Philipp Lenard, though, did not realize that he was producing X-rays. Hermann von Helmholtz formulated mathematical equations for X-rays. He postulated a dispersion theory before Röntgen made his discovery and announcement. It was formed on the basis of the electromagnetic theory of light (Wiedmann's Annalen, Vol. XLVIII). However, he did not work with actual X-rays.

Death at age 36[link]

In 1892, an infection was diagnosed (after a bout of severe migraines) and Hertz underwent some operations to correct the illness. He died of Wegener's granulomatosis at the age of 36 in Bonn, Germany in 1894, and was buried in Ohlsdorf, Hamburg at the Jewish cemetery.^{[citation needed]}

Hertz's wife, Elizabeth Hertz (maiden name: Elizabeth Doll), did not remarry. Heinrich Hertz left two daughters, Joanna and Mathilde. Subsequently, all three women left Germany in the 1930s and went to England, after the rise of Adolf Hitler. Charles Susskind interviewed Mathilde Hertz in the 1960s and he later published a book on Heinrich Hertz. Heinrich Hertz's daughters never married and he does not have any descendants, according to the book by Susskind.

Legacy and honors[link]

His nephew Gustav Ludwig Hertz was a Nobel Prize winner, and Gustav's son Carl Hellmuth Hertz invented medical ultrasonography.

The SI unit hertz (Hz) was established in his honor by the IEC in 1930 for frequency, an expression of the number of times that a repeated event occurs per second. It was adopted by the CGPM (Conférence générale des poids et mesures) in 1960, officially replacing the previous name, the "cycle per second" (cps).

In 1969 (East Germany), a Heinrich Hertz memorial medal^[11] was cast. The IEEE Heinrich Hertz Medal, established in 1987, is "for outstanding achievements in Hertzian waves [...] presented annually to an individual for achievements which are theoretical or experimental in nature".

Heinrich Hertz

A crater that lies on the far side of the Moon, just behind the eastern limb, is named in his honor. The Hertz market for radio electronics products in Nizhny Novgorod, Russia, is named after him. The Heinrich-Hertz-Turm radio telecommunication tower in Hamburg is named after the city's famous son.

Hertz is honored by Japan with a membership in the Order of the Sacred Treasure, which has multiple layers of honor for prominent people, including scientists.^[12]

Heinrich Hertz has been honored by a number of countries around the world in their postage issues, and in post-World War II times has appeared on various German stamp issues as well.

On his birthday in 2012, Google honored Hertz with a Google doodle, inspired by his life's work, on its home page.^[13][14]

Nazi revisionism[link]

Although Hertz would not have considered himself Jewish, his "Jewish" portrait was removed by the Nazis from its prominent position of honor in Hamburg's City Hall (Rathaus) because of his partly "Jewish ancestry." Hertz was a Lutheran; and although his father’s family had been Jewish,^[15] his father had converted to Catholicism before marrying.^{[citation needed]} The painting has since been returned to public display.^[16]

See also[link]

Notes[link]

References[link]

Further reading[link]

External links[link]

Wikimedia Commons has media related to: Heinrich Hertz

• Quotations related to Heinrich Hertz at Wikiquote
• Hertzian radiation - better known as radio waves: what it is and how it happens
• Encyclopædia Britannica (1911): Hertz biography

Manuel Contreras
Manuel Contreras
Born	(1929-05-04) May 4, 1929 (age 83) Santiago, Chile
Alias(es)	Mamo Contreras
Penalty	Life imprisonment
Status	Imprisoned

Juan Manuel Guillermo Contreras Sepúlveda (born May 4, 1929) is a Chilean military officer and the former head of DINA, during the dictatorship of General Augusto Pinochet. As head of DINA he was the most powerful man in the country, after Pinochet. He is currently serving 25 life sentences for kidnapping, forced disappearance and assassination.^[1]

Operation Condor[link]

From 1973 to 1977, Contreras led the agency on an international hunt to track down and murder the political opponents of the dictatorship, particularly members of the Communist and Socialist Parties and the violent Movement of the Revolutionary Left (MIR). According to the report "CIA activities in Chile" released on September 19, 2000, the US government policy community approved CIA's contact with Contreras from 1974 to 1977 to accomplish the CIA's mission in Chile in spite of his role in human rights abuses. By 1975 American intelligence reporting had concluded that Contreras was the principal obstacle to a reasonable human rights policy within the Pinochet's government, but the CIA was directed to continue its relationship with Contreras, even giving Contreras a one-time payment in 1975.^[2][3] The CIA became concerned with Contrera's role in the assassination of former Salvador Allende cabinet member and ambassador to Washington Orlando Letelier and his American assistant, Ronni Karpen Moffit in Washington, DC, on September 21, 1976. The CIA gathered specific, detailed intelligence reporting concerning Contrera's involvement in ordering the Letelier assassination, but some of the material remains classified and another portion has been withheld at the request of the US Department of Justice (CIA, 2000) CIA contacts with Contreras continued until 1977.^[3]

After Orlando Letelier's assassination, tensions between Contreras and Pinochet grew over the course of his tenure, and the DINA was closed down in 1977 and replaced with a new apparatus, the National Intelligence Center (CNI). By 1979, Contreras was out of the army after a short time at the rank of General.

Prison sentences and court investigations[link]

In 1995, a Chilean court sentenced Contreras to seven years in prison for the Letelier assassination. Contreras first rebelled against the Chilean justice, taking refuge in the South, and then in a military regiment and later in a military hospital ^[4] After a two-months escape, he was detained again in a military prison, where he completed his sentence in January 2001. He was afterwards placed under house arrest and then released.

In May 2002, Contreras was convicted as the mastermind of the 1974 abduction and forced disappearance of Socialist Party leader Victor Olea Alegria. Contreras was also convicted by an Argentine court in connection with the assassination of former Chilean army chief Carlos Prats and his wife Sofía Cuthbert in Buenos Aires in 1974. However, an extradition request by Argentina was denied by Chile. On June 2008, he received two life sentences for the assassination of General Prats and his wife.

On January 28, 2005 Contreras was put in prison for the disappearance of tailor and MIR member Miguel Ángel Sandoval in 1975. The sentence time is 12 years.

On May 13, 2005, Contreras submitted to Chile's Supreme Court a 32-page document that claimed to list the whereabouts of about 580 people who disappeared during Pinochet's rule. Human rights groups immediately questioned the information and its source, citing Contreras's years of deception and denials of responsibility for human rights abuses. Many of the details he provided were previously known, and some contradicted the findings of commissions that have investigated the disappearances. In the document he wrote that Pinochet personally ordered these repressive measures.

During the same May 2005 hearing to the Supreme Court, Contreras directly involved the CIA and Cuban anti-Castrist terrorist Luis Posada Carriles in the 1976 assassination of Orlando Letelier.^[5]

Contreras has accused Augusto Pinochet of having given the order of the assassination of Orlando Letelier and of Carlos Prats. He also declared to Chilean justice in 2005 that the CNI, successor of DINA, handed out monthly payments between 1978 and 1990 to the persons who had worked with DINA agent Michael Townley in Chile, all members of Patria y Libertad, the far-right movement which had been involved in the Tanquetazo : Mariana Callejas (Townley's wife), Francisco Oyarzún, Gustavo Etchepare and Eugenio Berríos.^[6] Assassinated in 1995, Berrios, who worked as a chemist for the DINA in Colonia Dignidad, also worked with drug traffickers and DEA agents.^[7]

Judge Víctor Montiglio, who succeeded judge Juan Guzmán, granted amnesty to Contreras in 2005, after his conviction in operation Colombo.

References[link]

External links[link]

• Juan Manuel Guillermo CONTRERAS SEPULVEDA, Trial Watch Profile, TRIAL

This biographical article needs additional citations for verification. Please help by adding reliable sources. Contentious material about living persons that is unsourced or poorly sourced must be removed immediately, especially if potentially libelous or harmful. (February 2011)

This article's tone or style may not reflect the encyclopedic tone used on Wikipedia. Specific concerns may be found on the talk page. See Wikipedia's guide to writing better articles for suggestions. (February 2011)

Professor Noreena Hertz (born 24 September 1967, London) is an English economist, author and campaigner.

In her 2002 book The Silent Takeover: Global Capitalism and The Death of Democracy, Hertz warned that unregulated markets, corporate greed, and over-powerful financial institutions would have serious global consequences that would impact most heavily on the ordinary citizen. Following the financial meltdown and recession of 2008-09, many commentators have described Hertz as insightful.^{[citation needed]}

Hertz's books have been published worldwide. Since the publication of The Silent Takeover in 2002, she has regularly appeared on television and radio programmes to discuss economics, politics, and globalisation.

Life and career[link]

Noreena Hertz is a great-granddaughter of British Chief Rabbi Joseph H. Hertz, and was born and brought up in London, England. When she was 20 years old, her mother, the fashion designer and feminist activist Leah Hertz, died of cancer.

Hertz attended North London Collegiate School, Westminster School, and University College London, UK, where she earned her Bachelor's degree.^[1] She then attended the Wharton School of the University of Pennsylvania, U.S. where she earned her MBA, before gaining a PhD in Economics from the University of Cambridge (King's). At the invitation of a professor at Wharton,^{[citation needed]} she then went to Russia to work for the World Bank and played a role in setting up the Russian stock exchange and in advising the Russian government on its privatisation programmes. Her disenchanted and highly critical Cambridge doctoral thesis, "Russian Business Relationships in the Wake of Reform", dispelling the myth of Russia's successful transition to a market economy and questioning the bank's requirements, was published in 1996.

In 2000, the left-leaning UK newspaper The Observer described Hertz as 'one of the world's leading young thinkers'; in 2001 Management Today named her amongst the top 35 women under 35,^[2][3] and Vogue magazine named her 'one of the world's most inspiring women'.

In 2002 The Silent Takeover was published. Hertz then turned her attention to the Middle East Peace Process, where she headed a 40-member research team of Palestinians, Israelis, Jordanians and Egyptians. She was selected as a 'Young Global Leader of Tomorrow' by the World Economic Forum in 2004.

In 2005, Hertz was appointed a Fellow of the Judge Business School, University of Cambridge. That year IOU: The Debt Threat was published. A popular treatise on the dangers of irrational lending, it was publicly endorsed by Archbishop Desmond Tutu, Bob Geldof and Bono. During 2005, Hertz also served a 6 month professorship at the University of Utrecht in the Netherlands.

As of 2006, Hertz is a fellow and associate director of the Centre for International Business & Management (CIBAM),^[4] at Cambridge's Judge Business School.

In 2006, Hertz played a leading role in the development of (RED) - an innovative commercial model to raise money for AIDS victims in Africa. The singer Bono was also closely involved in the project and has described Hertz's writings as the inspiration for the (RED) project. That year she was appointed Fellow of the Centre for Global Governance at the London School of Economics.

In 2008, Hertz took up a Visiting Professorship at Rotterdam School of Management, Erasmus University, the business school of Erasmus University Rotterdam in the Netherlands. Harpers Bazaar chose her as "one of the most powerful women in Britain" and described her as "one of the greatest communicators of our generation."

In 2009, Hertz was appointed Professor of Globalisation, Sustainability and Finance at Rotterdam School of Management, Erasmus University^[5] and the Duisenberg School of Finance.^[6]

Personal life[link]

Hertz is married to Danny Cohen, the controller of BBC One.

Books[link]

Hertz has published several studies on globalization and Russia. She has written several popular books based on her experience at the World Bank, including:

• 1997: Russian Business Relationships in the Wake of Reform (ISBN 0-333-71083-5)
• 2002: The Silent Takeover : Global Capitalism and the Death of Democracy (ISBN 0-7432-3478-2)
• 2005: The Debt Threat : How Debt Is Destroying the Developing World (ISBN 0-06-056052-5)
• 2005: IOU: The Debt Threat and Why We Must Defuse It (ISBN 0-00-717899-9)

Politics[link]

Hertz is considered to be on the centre-left, rather than the further left position of Naomi Klein, to whom she is sometimes compared.^{[citation needed]}

Campaigns[link]

In April 2007 Hertz launched a campaign in Britain to alleviate the problems of low pay in nursing. She asked several hundred top-flight footballers and managers to contribute a day's pay to a hardship fund for nurses struggling in their first few years, and above all to draw public attention to the issue.^[7]

The Royal College of Nursing is collecting and administering the fund, and as of October 2007 began the distribution process.

External links[link]

• Noreena Hertz's personal website (new)
• Noreena Hertz's TED Talk - "How To Use Experts - And When Not To" (new)
• Hertz interview with Bill Moyers
• Hertz essay on the future of capitalism, March 2009
• [3]

Footnotes[link]

1. ^ Jardine, Cassandra (31 March 2001). "Adventures of a high flier". The Telegraph - Culture. Telegraph Media Group. http://www.telegraph.co.uk/culture/4722576/Adventures-of-a-high-flier.html. Retrieved 31 January 2011. 
2. ^ [1]^{[dead link]}
3. ^ [2]^{[dead link]}
4. ^ UK (2010-08-27). "Centre for International Business & Management (CIBAM) - Faculty & Research - Cambridge Judge Business School". Jbs.cam.ac.uk. http://www.jbs.cam.ac.uk/research/centres/cibam/index.html. Retrieved 2011-02-03. 
5. ^ http://www.rsm.nl
6. ^ "Duisenberg school of finance, the best finance school in europe - Home". Dsf.nl. http://www.dsf.nl. Retrieved 2011-02-03. 
7. ^ Triggle, Nick (2007-04-17). "Health | Footballers highlight nurse woes". BBC News. http://news.bbc.co.uk/1/hi/health/6563277.stm. Retrieved 2011-02-03.