Category Archives: Science

Arts, Education, History, Science

Quantum Leaps: Hipparchus

C. 170–125 BC

HIPPARCHUS spent long periods taking measurements of the earth’s position in relation to the stars. The results enabled him to make several important findings and calculations.

. The Precession of The Equinoxes

He discovered what is now known as the “precession of the equinoxes” by comparing his own observations with those noted by Timocharis of Alexandria a century and a half previously together with earlier recordings from Babylonia. What Hipparchus soon realised was that by taking into account any observational errors made by his predecessors, the points at which the equinox (the two occasions during the year when day and night are of equal length) occurred seemed to move slowly but consistently from east to west against the backdrop of the fixed stars. He gave a value for the annual precession of around 46 seconds of the arc, which is exceptionally close to the modern figure of 50.26 seconds, given the tools and data then available to him.

. The Distance of The Moon

From these observations, Hipparchus was able to make much more accurate calculations on the length of the year, producing a figure that was accurate to within six and a half minutes.

He was also able to correctly determine the lengths of the seasons and offer more exact predictions of when eclipses would take place.

He made observations of the sun’s supposed orbit and attempted to do likewise with the more irregular orbit of the moon. Although partially successful, he could not make entirely accurate calculations.

Using measurements and timings related to the earth’s shadow during eclipses, other attempts were made to determine the size of the sun and moon and their distances from the earth. Again, while not entirely accurate, Hipparchus proposed that the distance of the moon from the earth was 240,000 miles. This is remarkably close to the modern figure.

. A Catalogue of Stars

Perhaps Hipparchus’ most important astronomical achievement was his plotting of the first known catalogue of the stars, despite warnings from some of his contemporaries that he was thus guilty of impiety. He was inspired to begin this work in 134 BC after allegedly seeing a “new star” which prompted his speculation that the stars were not fixed as had previously been thought.

He went on to record the position of 850 stars in the remaining years of his life, a significant achievement given the resources available to him. What is more, he devised a scale for recording a star’s magnitude or brightness: from the most visible (the first magnitude) to the faintest (the sixth). Though amended considerably, it is a scale still used today.

. Developing Trigonometry

Because of the accelerated developments Hipparchus was making in astronomy, he was required to break new ground in other disciplines, particularly mathematics, to facilitate his celestial observations and calculations. Most notably of all, he developed an early version of trigonometry. With no notion of sine available to him, he constructed a table of chords which calculated the relationship between the length of a line joining two points on a circle and the corresponding angle at the centre.

. Further Influence of Hipparchus

Although Hipparchus is considered to be one of the most influential astronomers of the ancient world, it is arguable that his most impacting achievements lay in the areas of mathematics and geography.

The geographer and astronomer Ptolemy cited Hipparchus as his most important predecessor, and he is most often revered for his astronomical measurements and cataloguing. Yet, as the attributed inventor of trigonometry, as well as being the first person to plot places on the earth’s surface using longitude and latitude, his influence has been long lasting and widespread.

He was able to apply his work on the trigonometry of spheres to the planet from which he made his observations. Significantly, he was the first person to use longitude and latitude in his mathematical calculations to position where places were on the earth’s surface. Like so many of Hipparchus’s achievements, it is his further pioneering work that still resonates today.

Hipparchus was born in Nicaea, Bithynia, now in modern Turkey, where he undertook some of his astronomical observations, along with sustained periods in Rhodes and to a lesser extent in Alexandria.

Most of the detail of Hipparchus’s life that has come down to us is taken from Ptolemy’s record of his achievements (because the vast majority of Hipparchus’s original work has been lost).

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Medical, Psychology, Science

(Quantum Leaps): Sigmund Freud

1856–1939

“The interpretation of dreams is the royal road to the unconscious activities of the mind.” – Freud

SIGMUND Freud’s popular impact remains profound even today. Yet for a scientist who changed the world, some critics would argue that his methods were at best unscientific and at worst downright reckless. Indeed, later thinkers in the fields of psychology and psychiatry have long since discredited many of his conclusions but still the Austrian’s influence pervades. Whatever the rights or wrongs of his ‘scientific’ deductions, Sigmund Freud remains the benchmark by which others working in the same field must compare themselves and compete against.

Medical Beginnings

Freud’s entry into science was far less controversial. He began by studying medicine at the University of Vienna in 1873 and went on to take up a position at a hospital in the same city from 1882. It was time spent working with the French neurologist Jean-Martin Charcot (1825–93) in Paris 1885, however, which set him on the path of his future career. Here he worked with patients suffering from hysteria and began to analyse the causes of their behaviour. Additional research with Josef Breuer back in Vienna during the early 1890s helped develop the basis for all of his future work, culminating in the publication of Studies in Hysteria in 1895.

The Idea of ‘Free Association’

In common with views generally held at the time, at the heart of Freud’s conclusions was a belief that mental illness was normally a psychological rather than a physical brain disease. Once one accepted this premise then Freud’s introduction of the idea of “psychoanalysis” for diagnosing the causes of mental disorder (and indeed ultimately to explain all mental behaviour) was a logical one.

One of the innovative tools he developed to aid in this was the idea of “free association”. Rather than hypnotise people as was traditional, Freud advocated this method whereby patients enunciated thoughts or ideas which came into their consciousness without prior contemplation or analysis.

Dream Theory

From this Freud believed he could make an insight into the “unconscious” of a patient and, in particular, the “repressed” thoughts and emotions (often related to past negative experiences) which their “conscious” prevented from being articulated or enacted upon. For Freud, having a patient understand and acknowledge their repressed desires was a route to therapy and ultimately the treatment of a mental disorder. He also believed that dreams offered a major insight into repressed thoughts held in the unconscious mind. This is shown in his most prominent work – which fully established his revolutionary approach – and which is entitled The Interpretation of Dreams, published in 1899.

While many critics were able to bear with – if not necessarily agree with – Freud’s interpretations up until this point, he caused an outcry with his 1905 Three Essays on the Theory of Sexuality. His conclusions included the explanation that most repressed behaviour was in essence suppression of sexual impulses and, most shockingly, this activity began in infancy. It was here that he also introduced the now notorious concept of the Oedipus complex, a phrase used by Freud to describe feelings of sexual attraction of a child for its parent of the same sex, and hostility to the parent of the other sex. This phrase, Freud claimed, speculatively at best, was one that all children passed through.

Gradually, however, Freud’s analyses would gain credibility, if not necessarily with everyone, and certainly by the 1920s they had entered the popular consciousness on a global scale. He wrote many other texts including the 1923 The Ego and the ID. Freud effectively redefined the “unconscious” as the “ID”, an intangible collection of base impulses such as instincts and emotions present in the mind from birth. With experience, living and structure, aspects of the ID would gradually help formulate a person’s “ego”.

Freud By Name, Freudian By Nature

Freud’s legacy remains as much in the tools of language that he has bestowed on the modern world as anything else. Terms he introduced or of which he altered the meaning to give them our now common understanding, include: psychoanalysis, free association, the ID, the ego, neuroses, repression, the Oedipus complex and, of course, the Freudian slip. The structured, systematic approach he brought to analysing an inherently difficult-to-quantify subject also pervaded the work of his successors in the field.

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Medical, Research, Science

How Do Our Genes Make Us Human?

MOLECULAR BIOLOGY

Intro: One thing common to all life on Earth, from bacteria to blue whales to bonobos, is a genetic code contained within strands of DNA. This leads to the perplexing question of how our DNA creates human beings.

LONG sections of genetic code are identical across the entire span of life. About 50 per cent of our own DNA sequence is the same as bananas’, while we share 98 per cent of our DNA with chimpanzees. So, what makes us different?

In April 2003, a major milestone in the study of human genetics was reached with the publication of the complete human genome. An enormous collaborative project worked on by scientists in 20 different countries, it may well come to be regarded in the same light as the great scientific landmarks. Principal among these was the work of the Augustinian monk Gregor Mendel – often referred to as the “father of genetics” – which he carried out in the 1850s and ‘60s and which first established the rules of heredity, as well as James Watson and Francis Crick’s 1953 description of the molecular structure of DNA as the now-famous double helix.

Gene Expression

The published genome contains the sequence of some three billion so-called base pairs, which constitute the genetic code in our DNA. The translation of the code made up by these base pairs is used to build up 20 different essential amino acids which, together with other amino acids we get from our food, combine in numerous different ways to form all the different proteins we require in our bodies. Geneticists used to think that the role of DNA was almost entirely concerned with providing a template for the manufacture of these proteins, but the complete genome showed that the sections of DNA which perform this function, our genes, only account for about two per cent of the total.

The function of the remaining 98 per cent, sometimes known as “junk DNA”, is not entirely known, but it has become increasingly apparent that much of it is not junk at all. It plays a role in, among other things, gene expression. This is the actual process by which the information contained in our genes is used to make up all the different tissues and organs in our body, through the process known as cell differentiation. Here, stem cells divide to produce different types of cells, such as liver cells or nerve cells. Unravelling the way in which one type of cell divides to produce a wide variety of different cells has proved to be extremely difficult and is currently one of the principal areas of genetic research.

The basic functioning of DNA in producing amino acids from the genetic code is relatively straightforward: the double-stranded DNA molecule effectively unzips, splitting apart the base pairs and revealing the code that is then copied by single-stranded RNA and used to assemble amino acids. But the control of this process, in which the required genes are activated and those not needed switched off, appears to be extremely complicated. Each advance in our knowledge of gene expression uncovers a whole new level of complexity that has to be unravelled. Beyond that, there is also the equally tricky problem of determining how, during the process of protein folding, the proteins made from genes assume the three-dimensional shape that determines their functions. The potential applications of our advancing knowledge of gene expression and protein folding are wide, not least in increasing our understanding and ability to treat diseases which have a genetic basis, prominent among which are many forms of cancer.

The Difficulties of Cloning

Another landmark in genetic research was achieved in 1996, when the first mammal (known as Dolly the Sheep) was cloned by geneticists at the University of Edinburgh in Scotland, using a technique called somatic cell nuclear transfer. This involves the removal of a nucleus containing genetic material from a cell of the animal to be cloned, and its introduction into an egg from which the original nucleus has been removed. The egg is then implanted into a surrogate mother and, in theory at least, will develop into an embryo with DNA identical to the animal from which the nucleus was taken.

Needless to say, if it were as easy as that, cloning would be a common occurrence today. In reality, it has proved much more difficult, in part because of the complications which arise as a consequence of gene expression. In some successful cloning experiments, for instance, the observable traits, or phenotype as it is known, of the cloned offspring are not always the same as those of the original animal. So, despite being genetically identical, the offspring looks different from the parent. In order to produce exact copies of the original, the process of cloning has to solve the complicated issues involved with gene expression, including the role of junk DNA in regulating genes. We are, it appears, a long way from seeking flocks of cloned sheep.

Alternative Theories

In recent years, it has become increasingly apparent that gene expression is not controlled solely by DNA but is also influenced by a number of external factors collectively known as epigenetics. This is a new field of scientific research and the details of how it works are disputed, but, in essence, it implies that the environment in which DNA replication occurs during cell division can influence the activity of genes and, in doing so, can have an effect on the resulting phenotype. This is thought to occur at a molecular level, through environmental factors modifying the actions of those proteins that surround strands of DNA and influencing the switching off or activation of genes. These epigenetic modifications do not change the DNA sequence of base pairs, so are not inherited by future generations, even if those generations may then be subjected to the same environmental conditions as the parent, resulting in similar epigenetic modifications.

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