The paper included a review of the literature and some of my own research work dealing with the relationship between vitamin A and tumors. In animal experiments and in clinical investigations vitamin A and vitamin A acid had shown a preventive effect on the development of tumors as well as a therapeutic effect on certain established premalignant and malignant epithehal lesions. [The SC/B indica...

In the preceding lectures, we discussed clustering. One view of clustering is that it’s a way to summarize a complex real-valued datapoint x ∈ R with a single categorical variable y ∈ {1, . . . ,K}. This could be useful for understanding and visualizing the structure in the data, as well as a preprocessing step for other learning algorithms. For example, we could build a very simple classifier ...

It was argued that a statistically significant finding, confirming a direction prediction based on a psychological theory, is usually an insignificant event. Replicability is the real desideratum. Three types of replication were identified and their importance discussed in terms of examples from the literature. [The Science Citation Index® (SC!®) and the Social Sciences Citation Index® (SSCI®) ...

In these lectures we will develop a quantitative model to describe the structure of the observable Universe as a whole. To begin, let us review the relevant physical scales. An Earth mass is 6× 1027 g ≃ 3 × 1051 GeV/c2 ≃ 3× 10−6 M⊙. Its radius is 6.4 × 10 8 cm. It spins around the Sun, which has a mass M⊙ = 2 × 10 33 g ≃ 1057 GeV/c2 and radius R⊙ ≃ 7 × 10 10 cm. The Earth-Sun distance is 1AU = ...

The movement of people from one country to another and the subsequent settling of migrants in host communities diversely affect all parties in relocation processes. Directly or indirectly, both migrant and their host communities respond differently to the worldviews of the migrants and the socio-cultural contexts of the host communities. While the religious beliefs of people appear to be the le...

Cartesian and polar form of a complex number. The Argand diagram. Roots of unity. The relationship between exponential and trigonometric functions. The geometry of the Argand diagram. 1 The Need For Complex Numbers All of you will know that the two roots of the quadratic equation ax + bx+ c = 0 are x = −b± √ b2 − 4ac 2a (1) and solving quadratic equations is something that mathematicians have b...

According to general relativity, the trajectories of light rays can be bent by gravitational fields. Massive objects can therefore gravitationally “lens” the images of objects behind them. A cosmological examples of gravitational lensing is lensing of galaxies or quasars at redshifts z ∼ 1 by elliptical galaxies or galaxy clusters along the line of sight. If the lensing is “strong,” then there ...