The PHD Movie

As a huge fan of the PHD comic, I have been looking forward to the PHD movie but it was not screened in my University, so I have to wait until it is available online! This is a great movie for graduate student. It hilariously accurately describes our life! And it keeps on reminding you about the piles of homework, test paper and lab reports that are lying around your table and floor waiting for your to mark! So now it's time to get back to work... -___-|||

sem + Graphviz

It is very difficult to draw path diagrams and SEM models in Microsoft Word / Powerpoint. Graphviz is a free program that worth trying out, together with the sem package in R (http://cran.r-project.org/web/packages/sem/index.html), drawing path diagrams with loading became a much easier tasks...

Download Graphviz
A guide on the syntax of Graphviz, if you are not using sem packages and have to code the path diagram yourself: How To Use Graphviz for SEM Models and Path Diagrams

方勵之先生，安息吧！

下午從電視得知方勵之先生離世的消息，感到很難過。方先生在民主運動後逃離祖國到了美國，到他今天離世，中國仍舊是老樣子，實在叫人黯然……


其實，知道方先生是因為《從牛頓定律到愛因斯坦相對論》，他是其中一位作者。這書對中學時代的我影響很大，可以說是我天文物理以至哲學的啟蒙老師。方先生用初中生也能懂的文字去講解廣義相對論、宇宙學和天體物理學的發展，當中提及的例子（如孖生兄弟去太空、在開動的火車裏於車頭和車尾開槍等）更令我對天文物理學產生了一種強烈的興趣，覺得空間時間等現象很厲害很不可思議。還記得當年我一口氣看了很多物理學和哲學的書籍，中六時更參加了科大的Physics Summer School，當時覺得物理學、量子力學等等很有趣（說來慚愧，這些我現在通通忘記了）。要不是同時參加了Engineering Summer Camp，而又覺得Computer Engineering有趣些，加上當年學校不鼓勵我們選讀純理科，或許我真的會讀物理學。


雖然現在與物理學無緣，但仍要多謝方先生讓我喜歡上天文物理學。謝謝方先生，願您安息。有空定要再看一遍《從牛頓定律到愛因斯坦相對論》和《宇宙的創生》。