Friday, July 10, 2009

TED

Lots of worthwhile ideas at TED:

Bonnie Basler gave a captivating talk on the discovery of how bacteria communicate. She suggests this is the origin of multicellularity, emphasises the practical importance of bacteria, and predicts that future antibiotics will focus on these communications rather than just killing bacteria.

Paul Ewald suggests taking advantage of evolution in the treatment of disease (rather than fighting it endlessly with pharmaceuticals). Vector diseases (e.g., malaria spread by mosquitoes) and waterbourne diseases (e.g., cholera spread by diarrhoea) tend to be more harmful because their transmission does not require the host to be healthy and mobile. Mosquito-proofing homes and hospitals and providing sanitary water supplies will (in addition to cutting transmission) favour strains that are more benign.

Steven Pinker, author of the captivating "Language instinct", notes that the rates of violence are decreasing through history (hence typical longing for more primitive times is misplaced), and that humans are obviously not born as blank slates (another case where political correctness seems to have gotten in the way of intellectual honesty).

Paul Collier...

Stewart Brand...

Jonathan Haidt gave an insightful talk on the political divide. Openness to new experience corresponds with liberalism (as well as intellectualism) rather than conservatism. He identifies the innate (though malleable) anthropological/evolutionary foundations of natural human morality as: harm/care, fairness/reciprocity, ingroup/loyalty, authority/respect and purity/sanctity (the latter exemplified not only in female sexuality but also organic food). Everybody supports the first two, but liberals reject the latter three (as the basis of xenophobia, etc). Essentially, conservatives appreciate stability even at the expense of the bottom few, whilst liberals are not averse to risking change. He relates (or less clearly juxtapositions) this to how cooperation can be shown in simple games to decay unless there is a punishment element. There is a balance to be had: he notes the insight of the asian religions to be that the destroyer and the preserver (or yin and yang) are not in opposition to one another; simply calling the bible-belt stupid isn't productive (he suggests the moral authority of the dalai lama comes from his moral humility).

Tuesday, June 16, 2009

Scientific history

Solar system model was originally fitted to basic astrometry (phases and relative sky position records, with scale by lunar parallax) [Kepler, early 1600's, Newton 1680's]. Distances within the solar system are now tracked by radar and telemetry.

Finite speed of light measured (relative to planetary orbital speeds) from Doppler shift in a signal (Io's stages) from Jupiter [Roemer, 1676] and annual aberration of stellar directions [Bradley, 1720's]. Direct local measurements are now trivial (e.g., modern computers can perform an instruction in a light handspan).

Lab measurements [Cavendish, 1798] of the gravitational constant permit the mass of astronomical bodies to be determined from the scale of orbital motions.

Relative molecular weights, along with the concept that ordinary matter is composed from elementary atoms, were inferred from the integer proportions in which chemicals react [Dalton, ~1805]. Absolute atomic masses (or Boltzmann's constant) were deduced from the behaviour of gasses [Loschmidt, 1865]. (A modern method would be crystal diffraction.)

Stellar parallax is the primary method for determining distance to stars in the nearby regions of the galaxy. [Bessel, 1838; Gaia, 2010's?].

Charge to mass ratios are found by mass spectroscopy, particularly for cathode rays and ions (permitting observation of distinct isotopes) [Thomson, c.1900]. The quantisation of electric charge can be measured directly [Millikan, ~1910].

Penetrating rays (that may trigger photochemical reactions or fluorescence) can be produced by cathode tubes [Roentgen, 1895]. Some substances spontaneously produce radiations [Becquerel, 1896], commonly of three types discernible by mass spectroscopy. The radioactivity process is atomic transmutation [Rutherford 1901; Curie], occurring randomly (to decay exponentially) [Geiger & Rutherford].

The nucleus of the atom was discovered by scattering [Rutherford, 1910].

Relativity [Einstein, 1905 & 1915].

The brightness of standard candles (Cepheid variable stars, having pulsation correlated to luminosity) identified in some extended astronomical objects showed that these are in fact separate galaxies (far more distant than the stars of our milky way galaxy), and furthermore their distance is roughly proportional with red-shift. That is, on the intergalactic scale everything is moving apart (at such a rate as if everything were together around 13 billion years ago) [Hubble, 1920's].

Understanding of life, mainly through fossil record [Darwin, 1859], DNA [1950's] and molecular biology.

Rotation curves, determined from the variation in red-shift across each galaxy, appear inconsistent with the visible distribution of matter (as though the motion of stars were influenced by large halos of invisible mass) [1959]. Gravitational lensing patterns around colliding (clusters of) galaxies appear to demonstrate electromagnetically observable matter becoming well separated from this dark matter [Bullet cluster, 2006].

Very distant standard candles are less red-shifted than would be extrapolated from their faintness, as though the universe is accelerating in its expansion. In General Relativity theory, this equates with the presence of a previously unobserved ("dark") form of energy. [Type Ia Supernovae, 1998]

Monday, May 4, 2009

History

13 billion years ago (Ga) Beginning of the universe.
5 Ga Formation of our sun.
600 million years ago (Ma) Multicellular organisms.
360 Ma Four limbed vertebrates.
At some later point, mammals branch into monotremes, marsupials and placentals. Tree-rodents separate into proto-flying lemurs and primates.
65 Ma Dinosaur extinction (except birds).
30 Ma Apes and monkeys part.
10 Ma Chimpanzees part from other apes.
7 Ma Other chimpanzees part with us.
4 Ma Walking upright.
2.5 Ma Use of stones as crude tools becomes common for East-African proto-humans.
1 Ma Omnivorous homo-erectus survives more robust-skulled proto-humans, expands from Africa into the east and europe. May control fire.
100,000BC Anatomically modern humans arise in Africa.
40,000BC Perhaps grammar? Tools become more complex. Localised cultural artifacts. Stone struck off larger stone for edges. Rope. Compound tools. Axes, needles, fish hooks, net-sinkers. Bows and arrows, darts, woomera, big game hunting begins. Neanderthals disappear. Australia colonised via Indonesia. Trade (nonlocal materials). Some begin to live to old age, becoming wealth of information (menopause?). Art.
9000BC North and South America colonised via Siberia and Alaska. (World human population of order ten million?)
8000BC Agriculture originates in near east, but takes over 2000 years to spread north-west. It permits larger population density, development of diseases, desertification.
4000BCDomesticated sheep, cows, pigs, horses and goats, in Western Eurasia.
3300BCWheel.
~2000BCBronze age.
500BCBuddhism founded amidst Hinduism.
~450-320BCSocrates, with the method for "recalling" new knowledge, and wisdom in professing ignorance. Plato, who thought our senses only convey distorted shadowy instantiations of ideal true forms. Aristotle, reasoned/speculated on the ideal elemental essences, celestial sphere..
330 CEAs the Roman Empire splits, Constantinople made capital of the Eastern Roman Empire. Roman empire also becomes Christian.
~500 CEWestern fall of Roman Empire, beginning of the Middle ages (with power dominated by the Catholic church, the remaining outposts of education).
630Muhammad conquers Mecca, after a series of battles. (Islam will dominate the Middle East, northern Africa, and Indonesia; a quarter of people are Muslim.)
800Charlemagne crowned emperor, in lead-up to the Holy Roman Empire (932), universities, Catholic/Orthodox schism (1054) and the crusades to retake Jerusalem.
830Persian Algoritmi fathers algebra, introduces Hindu-Arabic to west (spread around Mediterranean by Fibonacci of Pisa, 1202). This is the time of the Arabic translation movement, House of Wisdom, and the Islamic Golden Age. Alhacen fathers scientific method, 1021.
1350Black death halves population of Europe. Beginning of Renaissance, in which humanists focus on beauty and individuals and studying the ancients.
1517Protestant reformation, rejecting papal authority (and leading to separation of church and state). Leonardo da Vinci in Florence, centre of capitalism.
1632Galileo's controversy (and the writings of Descartes, 1637) contributes to the enlightenment, which advocates reason (and science as distinct from the church) as the legitimate source of authority.

Monday, April 20, 2009

Human evolution symposium

Bronya Keats described how population bottlenecks (or founding) associate particular groups and genetic diseases. Also discussed the rate at which alleles for recessive disorders are naturally reduced from a population, and contrasted the normal statistical distribution of genotypes (given allele abundances) with the displaced equilibriums that arise where there is a heterozygote advantage. In the case of sickle-cell anaemia in malaria-affected populations, the gene statistics demonstrate that we are still pressured today by natural selection.

Neil Risch shared data suggesting an over-reaction to racism. Contrary to claims that race is genetically insignificant, machine categorisation of individual genomes does cluster according to race. At the same time, the degree of genetic diversity within each cluster can be used to trace the ancestry (i.e., founder effects from the original dispersal out of Africa). He also discussed the difficulty of race-related genetic effects being confounded by social effects (e.g., a disease risk-factor among African-Americans may have no effect in Africa).

John Hopper argued that it would be more cost-effective for the government to provide genetic testing after early detection (when it may improve cancer treatment) rather than to subsidise using the test to prescreen healthy people (which disproportionately favours the wealthy, and still produces neglegible benefits because the rare individuals that test positive are still not prepared to take significant risk-reduction measures such as prophylactic excision). Looking at his use of flow charts (and my own first aid training), I wonder why we do not have epidemiologists produce a 'curriculum' (a standardised treatment flowchart) for doctors (and instead, we trust the doctors to keep their own expertise up-to-date, knowing that they are being distracted by advertisers)?

Monday, April 13, 2009

Aikido Canberra

(For updates see: Official Aikikai Canberra webpage)

Aikido is fun! It is a form of personal development with the excitement of martial confrontation, the skill of a refined art, and the satisfaction of good exercise.

Aikido involves blending with and redirecting the aggressor's movement (instead of directly opposing with force) to restrain or evade without needing to inflict injury. Aikido is non-competitive (and retains techniques that would not be safe for competitions), the idea is to refine one's self rather than conflict with others. "Aikido" can be translated as "harmonising discipline".

A typical class warms up first with stretching, the time is then punctuated with demonstrations of specific techniques by the instructor, and the bulk is spent practising those techniques in pairs (or small groups). Students take turns to attack or to respond to being attacked, and frequently change partners (so that everyone can train with the more advanced students and with people of different builds). Sometimes training involves weapons (e.g., sword, staff and knife) or multiple attackers.

Aiki-Kai Australia is the local mainstream aikido organisation; we are recognised by the Aikikai Foundation in Japan (headed by the heir of the founder of aikido) and member of the IAF (which organises international events). The technical instruction is overseen through the foundation of Sugano shihan (who introduced aikido to Australia at the direction of the founder of aikido). It has dojos in every state of Australia and organises week-long national training camps every six months (so that students can learn from more senior instructors than their local areas possess).

In Canberra, Australian Capital Territory (ACT), we currently train in two locations and invite you to come and watch a class:

  • Main dojo, learn directly from Hanan Janiv 7th dan shihan. Scout hall, Tooms Pl, Lyons. Wednesday, 7:30-9pm. Possibly also Friday or Monday, contact for details.
  • ANU SRA dojo (The Australian National University). Tuesday 7:30-8:30pm and Sunday 5:00-6:30pm.

Beginners may commence anytime. The simplest option is just to enroll (for a semester) in our ANU dojo beginners' course, at which no special clothing or equipment is expected. Comitted students instead join the national organisation, pay monthly, then (to train in both locations) join ANU Aiki-Kai club and become Sports Union associates (or be ANU students). The total cost per training session works out about the same as taking public transport.



For more specifics, try contacting people via aikido.org.au or the facebook group.

Saturday, April 11, 2009

Physics topics

I'm interested in writing a book to introduce advanced physics to high-school level interested people. Sketch of the topics (hopefully covering all the examples that are important to everyday life and public debate.. should perhaps outline this, and the philosophy, in the first section, perhaps leaving history to brighten the later parts). Maybe the way to pull this off is to only loosely break it into these chapters, but strongly break it into small independent sections: that way mathematical detail can be contained, elsewhere it can be written for a most general possible audience, with loads of pictures (not just technical diagrams). It probably also makes it more fun to write, and useful to a broader crowd.

Physics is the reductionist science. A systematic evidence-based pursuit of knowledge, by the approach of deducing complex system behaviour from the dynamics of simpler individual components, and with emphasis on mathematics of the interactions rather than on cataloguing the complex systems.

Newtonian mechanics. This is always first, getting preliminaries out of the way (levers/gears/pulleys). Important topics: gyroscopes and Coriolis (i.e., unintuitive emergent stuff), waves (the foundations for understanding QM, such as Fourier, and can take examples of sound), impedence matching, fluids/flight. Vector calculus, trig., Lagrangians, conserved quantities. Surface tension (possibly need to break class. mechanics into simple and sophisticated techniques, or sections to showcase different mathematical concepts?).

Thermodynamics. The focus is statistics; gases are just an isolated example. Also cover heater efficiency, Carnot efficiency, stimulated emission, ..

QM. All just classical wave stuff really.

Electromagnetism: from the forces on static-charged pith-balls and magnetised iron-filings or compass needles. Self-consistency argument for Maxwell's equations. Leads to optics, electronics, relativity (Lorentz symmetry), and field theory (gauge symmetry).

Electronics (passives, relays to op amps and computers, meter/motor/generator, radio).

Optics. (This comes after QM.) Why stuff looks how it does.

Special relativity. Heuristic approach? Emc2. Paradox of FTL. Twins with focus on acceleration phase. Rotating disc.

Nuclear. This topic isn't tightly connected to the others, but is important (controversial) and poorly studied. Particle zoo.

General relativity. The idea is to explain basic differential geometry, and just give a fleeting example of an actual space-time. Tensors should have been introduced earlier.

QFT. Show field lagrangian of multiparticle QM. Fibre bundle stuff. Non-scalar stuff.