https://bobostory.wordpress.com List

  • -
    3 hours ago
  • Greetings, from Home Sweet Hole ‘N the Rock - [image: Greetings, from Home Sweet Hole ‘N the Rock] We interrupt your life above ground for some unsolicited subterranean splendour. It’s just a quick pi...
    5 hours ago
  • 翻译:身份政治 - 恩:难道宗教不也是一个问题?伊斯兰教是一个非常传统的宗教,其中妇女的权利遭到了很大限制。看看许多穆斯林的移民,难道我们不应该担心这种不同价值观的相遇会给我们的社会带来问题吗? 巴:我认为这种恐惧被完全夸大了,这也十分肤浅。这是西方人的发明,一种幻觉。在我小时候,法国农村的普通妇女带头巾很正常,因为她们是基督...
    1 day ago
  • 牛肚 - 牛胃由四個胃室組成,即瘤胃、網胃、瓣胃和皺胃。聽學名,有點恐怖。廣東人最會起名了,把第二個叫成金錢肚,因為胃壁 […]
    1 week ago
  • 慕娜桑.桑白 - 1.慕娜桑.桑白作品(1) 2.慕娜桑.桑白作品 (2) 3.慕娜桑.桑白作品 (3) 4.慕娜桑.桑白作品 … 繼續閱讀 慕娜桑.桑白
    1 week ago
  • 許定銘:慕娜桑.桑白 - 1.慕娜桑.桑白作品(1) 2.慕娜桑.桑白作品 (2) 3.慕娜桑.桑白作品 (3) 4.慕娜桑.桑白作品 (4) 5.慕娜桑.桑白作品 (5) 6.慕娜桑.桑白作品 (6) 在香港報界活躍五十多年,一直是社長及總編輯級別的老報人馮兆榮,是一九五O年代的文藝青年。在一九五八至六O年間他曾和木石及蔡...
    1 week ago
  • Video: The Rate and Mass of Growth - [event starts at 2:00] In this lecture, David Harvey offers a close reading of Volume III of Karl Marx’s Capital to distinguish the rate of growth versus ...
    5 weeks ago
  • 蔡浩泉、張灼祥、西西、張海素、鍾玲玲、馬康麗1981年照片 - 鬍鬚張和大頭蔡 Victor Hui:應該在西貢,約一九八一。阿蔡怕冷,張校長穿背心,他要穿羽絨。他的皮包裡長期塞著這類外套和其他衣物、雜物,隨時可以「走路」的樣子。這是一次素葉和大拇指的聯合郊遊,為何有此一遊?Sorry,唔記得咗。 (圖片來自蔡浩泉臉書專頁2019年9月1日) (評論來自《大拇指》...
    2 months ago
  • 畧說《承教小記》和《豐子愷漫畫選繹》的版本 - 《承教小記》版本 跟書友談起小思《承教小記》的版本,我見過三種,封面都不同: 明 … 繼續閱讀 →
    5 months ago
  • 畧說《承教小記》和《豐子愷漫畫選繹》的版本 - *《承教小記》版本* 跟書友談起小思《承教小記》的版本,我見過三種,封面都不同: 明川出版社1983年7月初版 華漢文化1986年2月增訂再版 華漢文化1990年3月第三版 書友覺得明川版最難找,但這個版本我倒不時見到,可能大家都識貨,覺得珍貴,沒有隨便棄掉,就仍有流傳。 現在坊間常見的,是華漢三版以後...
    5 months ago
  • 財富之城──威尼斯 - 剛讀完Roger Crowley(羅傑.克勞利)有關威尼斯共和國歷史的著作: City of Fortune: How Venice Won & Lost a Naval Empire (財富之城──威尼斯怎樣嬴取及失去其海上帝國)(台版:《財富之城──威尼斯共和國的海洋霸權》),作為我近年來閱讀地中海和威尼...
    8 months ago
  • Tarot (塔羅與靈修) - 古老的符號系統一般都有兩種用途:占卜與靈修 。在功利的社會裏,占卜必然成為大部分人學習它們的主因。然而,若你能用靈修的系統去默觀它們,你可能會發現更偉大的真理。 舉例,在每天的星座運程底下,埋藏著一個人的成長過程:從天真的嬰孩白羊、勤勉的學生金牛、闖蕩的青年雙子、成家的母性巨蟹、領導的父性獅子、思考的智者處女、...
    9 months ago
  • 杭寧遊記 - 我的藏書裡有二部古籍和西湖相關,一是《御覽西湖志纂》,一是《西湖志》。
    1 year ago
  • 蘇賡哲:城寨和大學 - 12月5日多倫多明報 據説日本人最喜歡的香港特色地區是已消失了的九龍城寨,改建成公園已久,他們仍出版一本又一本追憶書籍。 以前家在九龍城賈炳達道,城寨自然也是熟悉的。所謂三不管黃、賭、毒集中地,髒亂無序不難想像。中共智囊強世功稱之為「一切人類道德所鄙視的東西,在這裏可以合法存在」。其實這話是有語病的,因...
    1 year ago
  • 釐清香港議員取消資格案的法律概念:又名「跳出跳入打我呀笨蛋」然後被打 - 好多人真的不懂法律又要講法律。又有好多人以為只有香港才會有「人大釋法」。任何一個 … 繼續閱讀 →
    2 years ago
  • 照顧與創作 - 月前為谷淑美的攝影詩文集《流光.時黑》做了中文部分的編輯工作,實在因為是一種唇亡齒寒感。谷淑美的書,是關於她照顧年老患病的母親,過程中進而對母親生命、自己生命的發掘,轉化為攝影與文字創作。自己進入中年,身體開始變差,也進一步想到將來要照顧家人的責任,暗暗畏懼其龐大。於是,也就想通過進入谷淑美的歷程,讓自己學...
    2 years ago
  • - 暗夜小巴像搖骰,我們每個橫切面都刻了字,不知我們在終站會變成甚麼。或者是上帝,或者是狗。或者倒轉的日歷。紙張一天一天倒著依附,雨中有人望過來問:為甚麼不可以?聽到問題的人,心裡又虛又慌,因為撇除了時日的制裁,也沒有多麼費力。耗費也是不足夠的。如果真的有努力過的話,根本不會站在這裡。喂,他其實一早...
    2 years ago
  • 《別字》試刊號第二期出版﹗ - 立即下載:《別字》試刊號第二期 《字花》的網上純創作誌《別字》登場了! 「別字」一名,既有別冊之意,更寄望透過網上平台,另闢傳播門徑,開拓閱讀體驗。 暫定三個欄目,「透光」的作品從自由投稿中特別挑選,「有時」配合《字花》徵稿或另設新題,「極限」則專載萬字長篇。 試刊號第二期,以PDF形式呈現,供各位下載...
    2 years ago
  • 酒足飯飽。酣然入夢——江戶子的老派追求 - 東京適合散步。出了名的散步文士,堪稱達人者有二:二次大戰前,搞不定老婆,不想吵,遂攜著一把蝙蝠傘,四處趴趴走的永井荷風;戰後,老婆、老母擺得一平二穩,隨身帶著幾張江戶古地圖,這邊那邊亂亂踅的池波正太郎。 *正港的江戶子* 池波是正港的「江戶子」,淺草出身,愛玩愛熱鬧愛美食。父母親很早離異,跟著...
    3 years ago
  • 乌托邦遗迹 - [image: uploads/201510/18_114414_s1.1973peterderret.jpg] [水瓶节,宁宾,1973年。摄影:Peter Derret] 乌托邦遗迹 欧宁 宁宾(Nimbin)是澳大利亚新南威尔士东北部山区的一个小镇,因1973年举办水瓶节(Aquarius Fes...
    4 years ago
  • 「馬拉松 看世界」專頁 向世界馬拉松出發 - 如無意外,本周日我應該身在三藩巿,跑今年第五個外國比賽,也是人生第三十個馬拉松比賽(廿九個在香港以外)。雖然Blog有好一段日子沒有update,但跑步仍是繼續下去,這兩年尤其多,也去了俄羅斯、澳洲這些新國家、新大陸跑,是另一個飛躍期。 這些年的跑馬路上,有幸認識一些志同道合、見識廣博、洞察力強、對比賽有要...
    4 years ago
  • 自由路艱:再思肖友懷事件 - 文:野莩遣返或特赦肖友懷,無絕對之可不可行,但決定時當先考慮法理依據,而非道德情懷。我曾就此事詢問一位在入境處工作的朋友,她的答覆非常簡單:「1. 依法當遣返事主;2. 父母非港人,事主不能申請單程證;3. 除了酌情,事主無其他留港途徑。」那麼酌情先例會為制度開漏洞嗎?「Personally speaking...
    4 years ago
  • 烏蘭巴托的夜 - 《烏蘭巴托的夜》是首蒙古歌曲。蒙古的作曲家寫的,賈樟柯重新填了詞,左小祖咒改編,電影《世界》插曲(湖南台的字幕打錯了)。左小原版的就好聽,他少有的比較「正經」地演唱。譚版也不錯,大氣,聲情並茂。 左小改編演唱的《烏蘭巴托的夜》 賈樟柯電影片斷(趙濤演唱) 蒙古族樂隊杭蓋的版本 烏蘭巴托的夜 作詞:賈樟...
    4 years ago
  • 莉娜骑士在盘子上 - 1874年12月25日,一个女孩诞生在罗马北部小城维泰博的贫民窟,迷信说,这一天诞生的人有特别的命运,父母为她取名“娜塔莉娜”(Natalina ),因为“natale”是意大利语里的“圣诞节”。12 岁开始,她当过卖花姑娘、包装女工,生活虽然贫寒,好在她天赋歌喉,每天从早唱到晚。邻居一个音乐教师给她上...
    4 years ago
  • 欲望的事故 - 欲望的事故 顾文豪 特里林在《知性乃道德职责》一书中引述亚里士多德关于悲剧的定义,认为悲剧的主人公具有某种程度的、可进行自由选择的可能性,他“必须通过自己的道德状况来为自己的命运进行辩解”,而其道德状况并非十全十... *博客大巴,你的个人传媒早班车*
    5 years ago
  • 給《明報》 - 一口答應寫一篇給《明報》,箇中心情,猶如「償還」。 明明我沒有欠這報甚麼,稿債沒有,瓜葛沒有。 都是人情吧。多老套。 這些年來,跟《明報》的這些年來,救命,怎麼細數。 第一次認真寫稿刊登,已是2003年的事了。正是馬家輝博士邀請,給世紀版寫一篇關於「網上飄流的香港家書」。(私人回憶:先生有份跟我寫的。)一年過...
    5 years ago
  • 那一身華美的曲線 - [image: 那一身華美的曲線] 她就站在落地窗邊,回眸對我笑了笑。我沒說話,什麼話都不想說。能說什麼呢?在她的笑容裏早就透露了對我些微的輕視:你總歸只能沈默吧!她似乎視我的沈默為一種必然的結果,像是看透我的一切。其實,我想了想,和她也不過就一面之緣。甚至在之後的好長一段時間再見到她,她根本就不記得我。自然,要...
    6 years ago
  • 召喚 新春秋 - 召喚 新春秋 諸劍仙現身, 草草一刀 頓首
    6 years ago
  • 偶然的發現 - 很久沒在facebook上看到湯正川的post,早上偶然看到他與另一DJ的對談,發現這首歌,先放上來,待電腦回復正常,再仔細欣賞。
    6 years ago
  • 汪曾祺佚文:黑罂粟花——李贺歌诗编读后 - *黑罂粟花——李贺歌诗编读后* *汪曾祺* * 下午六点钟,有些人心里是黄昏,有些人眼前是夕阳。金霞,紫霭,珠灰色淹没远山近水,夜当真来了,夜是黑的。 有唐一代,是中国历史上最豪华的日子,每个人都年轻,充满生命力量,境遇又多优裕,所以他们做的事几乎全是从前此后人所不能做的,从政府机构、社会秩...
    6 years ago
  • - *Chapeau...!*Cock your hat - angles are attitudes (Sinatra) By Heinz Decker Hats seem to stimulate the imagination; maybe because they are a prolongatio...
    7 years ago
  • 閱讀讓我質疑制度 - [本訪問稿乃〈不可能所有的真實都出現在你的攝影機前──賈樟柯、杜海濱訪談〉的第一部份。訪問稿全文網上版見以下網頁: http://leftfilm.wordpress.com/2012/07/17/jiaduinterview1/ http://leftfilm.wordpress.com/2012/07/17...
    7 years ago
  • 蜚聲卓越在書林──蘇州文育山房 - 蘇州的氣候溫潤,步調舒緩,水道與巷弄縱橫交錯,教人一來到此便安下心來。城裡的平江街區,從宋代便已經存在,以今日留存的巷弄來看,八百年來的格局規劃變化並不大,只是範圍縮小許多。而就在這僅存的街區裡,留下的不只是悠悠時光,亦有不少哲人賢士駐守的痕跡。書癡黃丕烈的百宋一廛、史學家顧頡剛的顧氏花園、清代狀元洪...
    7 years ago
  • 當世界留下二行詩 宣傳BV - 當世界留下二行詩瓦歷斯.諾幹Walis.Nokan本書以極簡的形式,現代詩行的排列,挑戰詩藝和語境的實驗風格觀察視角從台灣的土地與家園,擴及到族群、社會乃至世界的關懷。動情至深,引發共鳴,為作者近年來最新創意力作!短短的二行詩,宛如「芥子納須彌」激起無限想像空間,是一本趣意盎然、值得珍藏的現代詩集。向陽、李...
    7 years ago
  • 【读品】2011年第六期(总110辑) - 编辑手记 十六日成为我每一个月的终结与开始,这会产生一种错觉,好像每一期【读品】的诞生都在遥远且神秘地呼应着月亮与潮汐的关系。久而久之,时间不再是均质的,也不机械,而是紧密依附于自然的节奏,循环往复。我有时浑然不知星期中每天的意义,只知每月时间节点迫近,因为生物钟已早于理智做出判断:让所有...
    8 years ago
  • V城系列明信片 - 圖:by 智海 and 楊智恆
    8 years ago
  • 诗歌是飞行术,散文是步兵 - *诗歌是飞行术,散文是步兵顾文豪* *刊于《南方都市报——阅读周刊》2009年10月11日* 在众多优秀诗人看来,散文不是适合他们展露才思表陈感情的文体,偶然为之,亦不过如布罗茨基所说的是一种“以其他方式延续的诗歌”。他还有另一个比喻———诗歌是飞行术,散文则是步兵。 是的,诗人兴许能在...
    9 years ago
  • 《般若波罗蜜多心经》印存 - 《般若波罗蜜多心经》印存 般若波罗蜜多心经 35*35*138mm 薄意山水巴林红丝冻石 观自在菩萨 26*35*80mm 貔貅钮巴林黄冻石 行深般若波罗蜜多时 30*38*90mm 貔貅钮巴林冻石 照见五蕴皆空 33*33*114mm 螭钮巴林黄彩石 度一切苦厄 25*2...
    11 years ago

Sunday, March 23, 2014

邊度有書:澳門獨立書店風景


好吧,這次就別去金沙、也不要光留在威尼斯人酒店,去議事亭前地吧。不只行街購物,拾級而上,到訪這家澳門少見的獨立書店,你便體會到另一番光景。
書店名為「边度有書」,語帶相關,一是疑惑的詢問哪裏有書本?另一重意思則是以感嘆的語氣道出現代社會不堪的閱讀風氣-「(在社會上)哪裏有書啊!(眼睛只看到錢吧)」
當然這只是筆者個人的想像啦,別當真。然而書店門前的樓梯旁卻掛上一塊小字牌,寫著「只要閱讀,澳門邊度有‘輸’」。說的也是,這書店的出現,正好說明澳門不只賭場業務蓬勃。數百坪的二樓空間內,售賣不少中港台書籍,中、英文都有,而選書都是以人文氣息濃厚為主,說著社會上的故事,也說風土人情。譬如是講解活字印刷的書本、講述社會運動和抗爭的外國雜誌、紀錄緬甸旅遊趣事及生活紀錄的雜誌等等,你都會在「边度有書」找到。
店內窗戶旁有綠油油的植物,前面還有張三人座沙發及方形小桌子,上面擺放自家製橡皮圖章、音樂 CD 和耳筒,你可以買杯公平貿易咖啡,邊聽音樂邊為店家留言,隨興寫下想對他們或其他訪客說的話。正當很多野心勃勃的都市人只為生存打拼,忘記如何享受生活,便是時候走進這個不講輸贏的地方,翻開一兩本書或雜誌看看,將呼吸調慢下來吧。
很多遊客慕名前來看望書店內的小貓,看來獨立書店和貓咪的確是對好伴侶。另外,「边度有書」亦有自家出版,雖然為數較少,但亦是用心之作。而他們出品的帆布袋也是非常討喜,設計簡單樸素。
如果不太喜歡看書,可以再上一層到三樓,那裏有姊妹店「边度有音樂」,售賣黑膠唱片、店主精心挑選的各類唱片、原創手作雜貨,能看出經營者的用心。兩家店的牆上均貼滿文藝活動海報、明信片、即影即有相片等。如果喜歡貓貓,還可以留意上面有沒有與貓相關的活動。
「边度有書・边度有音樂」告訴人們的,除了推廣閱讀風氣這種老掉牙口號以外,正如書店的網誌所寫:「讓日本子再慢一點,再慢一點⋯⋯」

Wednesday, March 12, 2014

The 17 Equations That Changed The Course Of History


Mathematics is all around us, and it has shaped our understanding of the world in countless ways.
In 2013, mathematician and science author Ian Stewart published a book on 17 Equations That Changed The World. We recently came across this convenient table on Dr. Paul Coxon's twitter account by mathematics tutor and blogger Larry Phillips that summarizes the equations. (Our explanation of each is below):
Here is a little bit more about these wonderful equations that have shaped mathematics and human history:
pythagorean theorem chalkboard
Shutterstock/ igor.stevanovic
1) The Pythagorean Theorem: This theorem is foundational to our understanding of geometry. It describes the relationship between the sides of a right triangle on a flat plane: square the lengths of the short sides, a and b, add those together, and you get the square of the length of the long side, c.
This relationship, in some ways, actually distinguishes our normal, flat, Euclidean geometry from curved, non-Euclidean geometry. For example, a right triangle drawn on the surface of a sphere need not follow the Pythagorean theorem.
2) Logarithms: Logarithms are the inverses, or opposites, of exponential functions. A logarithm for a particular base tells you what power you need to raise that base to to get a number. For example, the base 10 logarithm of 1 is log(1) = 0, since 1 = 100; log(10) = 1, since 10 = 101; and log(100) = 2, since 100 = 102.
The equation in the graphic, log(ab) = log(a) + log(b), shows one of the most useful applications of logarithms: they turn multiplication into addition.
Until the development of the digital computer, this was the most common way to quickly multiply together large numbers, greatly speeding up calculations in physics, astronomy, and engineering. 
3) Calculus: The formula given here is the definition of the derivative in calculus. The derivative measures the rate at which a quantity is changing. For example, we can think of velocity, or speed, as being the derivative of position — if you are walking at 3 miles per hour, then every hour, you have changed your position by 3 miles.
Naturally, much of science is interested in understanding how things change, and the derivative and the integral — the other foundation of calculus — sit at the heart of how mathematicians and scientists understand change.
Isaac Newton
Isaac Newton
4) Law of Gravity: Newton's law of gravitation describes the force of gravity between two objects, F, in terms of a universal constant, G, the masses of the two objects, m1 and m2, and the distance between the objects, r. Newton's law is a remarkable piece of scientific history — it explains, almost perfectly, why the planets move in the way they do. Also remarkable is its universal nature — this is not just how gravity works on Earth, or in our solar system, but anywhere in the universe.
Newton's gravity held up very well for two hundred years, and it was not until Einstein's theory of general relativity that it would be replaced.
5) The square root of -1: Mathematicians have always been expanding the idea of what numbers actually are, going from natural numbers, to negative numbers, to fractions, to the real numbers. The square root of -1, usually written i, completes this process, giving rise to the complex numbers.
Mathematically, the complex numbers are supremely elegant. Algebra works perfectly the way we want it to — any equation has a complex number solution, a situation that is not true for the real numbers : x2 + 4 = 0 has no real number solution, but it does have a complex solution: the square root of -4, or 2i. Calculus can be extended to the complex numbers, and by doing so, we find some amazing symmetries and properties of these numbers. Those properties make the complex numbers essential in electronics and signal processing.
6) Euler's Polyhedra Formula: Polyhedra are the three-dimensional versions of polygons, like the cube to the right. The corners of a polyhedron are called its vertices, the lines connecting the vertices are its edges, and the polygons covering it are its faces.
A cube has 8 vertices, 12 edges, and 6 faces. If I add the vertices and faces together, and subtract the edges, I get 8 + 6 - 12 = 2.
Euler's formula states that, as long as your polyhedron is somewhat well behaved, if you add the vertices and faces together, and subtract the edges, you will always get 2. This will be true whether your polyhedron has 4, 8, 12, 20, or any number of faces.
Euler's observation was one of the first examples of what is now called a topological invariant — some number or property shared by a class of shapes that are similar to each other. The entire class of "well-behaved" polyhedra will have V + F - E = 2. This observation, along with with Euler's solution to the Bridges of Konigsburg problem, paved the way to the development of topology, a branch of math essential to modern physics.
bell curve
The normal distribution.
7) Normal distribution: The normal probability distribution, which has the familiar bell curve graph to the left, is ubiquitous in statistics.
The normal curve is used in physics, biology, and the social sciences to model various properties. One of the reasons the normal curve shows up so often is that it describes the behavior of large groups of independent processes.
8) Wave Equation: This is a differential equation, or an equation that describes how a property is changing through time in terms of that property's derivative, as above. The wave equation describes the behavior of waves — a vibrating guitar string, ripples in a pond after a stone is thrown, or light coming out of an incandescent bulb. The wave equation was an early differential equation, and the techniques developed to solve the equation opened the door to understanding other differential equations as well.
9) Fourier Transform: The Fourier transform is essential to understanding more complex wave structures, like human speech. Given a complicated, messy wave function like a recording of a person talking, the Fourier transform allows us to break the messy function into a combination of a number of simple waves, greatly simplifying analysis.
 The Fourier transform is at the heart of modern signal processing and analysis, and data compression. 
10) Navier-Stokes Equations: Like the wave equation, this is a differential equation. The Navier-Stokes equations describes the behavior of flowing fluids — water moving through a pipe, air flow over an airplane wing, or smoke rising from a cigarette. While we have approximate solutions of the Navier-Stokes equations that allow computers to simulate fluid motion fairly well, it is still an open question (with a million dollar prize) whether it is possible to construct mathematically exact solutions to the equations.
11) Maxwell's Equations: This set of four differential equations describes the behavior of and relationship between electricity (E) and magnetism (H).
Maxwell's equations are to classical electromagnetism as Newton's laws of motion and law of universal gravitation are to classical mechanics — they are the foundation of our explanation of how electromagnetism works on a day to day scale. As we will see, however, modern physics relies on a quantum mechanical explanation of electromagnetism, and it is now clear that these elegant equations are just an approximation that works well on human scales.
12) Second Law of Thermodynamics: This states that, in a closed system, entropy (S) is always steady or increasing. Thermodynamic entropy is, roughly speaking, a measure of how disordered a system is. A system that starts out in an ordered, uneven state — say, a hot region next to a cold region — will always tend to even out, with heat flowing from the hot area to the cold area until evenly distributed.
The second law of thermodynamics is one of the few cases in physics where time matters in this way. Most physical processes are reversible — we can run the equations backwards without messing things up. The second law, however, only runs in this direction. If we put an ice cube in a cup of hot coffee, we always see the ice cube melt, and never see the coffee freeze.
AP050124019477
Albert Einstein
13) Relativity: Einstein radically altered the course of physics with his theories of special and general relativity. The classic equation E = mc2 states that matter and energy are equivalent to each other. Special relativity brought in ideas like the speed of light being a universal speed limit and the passage of time being different for people moving at different speeds.
General relativity describes gravity as a curving and folding of space and time themselves, and was the first major change to our understanding of gravity since Newton's law. General relativity is essential to our understanding of the origins, structure, and ultimate fate of the universe.
14) Schrodinger's Equation: This is the main equation in quantum mechanics. As general relativity explains our universe at its largest scales, this equation governs the behavior of atoms and subatomic particles.
Modern quantum mechanics and general relativity are the two most successful scientific theories in history — all of the experimental observations we have made to date are entirely consistent with their predictions. Quantum mechanics is also necessary for most modern technology — nuclear power, semiconductor-based computers, and lasers are all built around quantum phenomena.
15) Information Theory: The equation given here is for Shannon information entropy. As with the thermodynamic entropy given above, this is a measure of disorder. In this case, it measures the information content of a message — a book, a JPEG picture sent on the internet, or anything that can be represented symbolically. The Shannon entropy of a message represents a lower bound on how much that message can be compressed without losing some of its content.
Shannon's entropy measure launched the mathematical study of information, and his results are central to how we communicate over networks today.
16) Chaos Theory: This equation is May's logistic map. It describes a process evolving through time — xt+1, the level of some quantity x in the next time period — is given by the formula on the right, and it depends on xt, the level of x right now. k is a chosen constant. For certain values of k, the map shows chaotic behavior: if we start at some particular initial value of x, the process will evolve one way, but if we start at another initial value, even one very very close to the first value, the process will evolve a completely different way.
We see chaotic behavior — behavior sensitive to initial conditions — like this in many areas. Weather is a classic example — a small change in atmospheric conditions on one day can lead to completely different weather systems a few days later, most commonly captured in the idea of a butterfly flapping its wings on one continent causing a hurricane on another continent
17) Black-Scholes Equation: Another differential equation, Black-Scholes describes how finance experts and traders find prices for derivatives. Derivatives — financial products based on some underlying asset, like a stock — are a major part of the modern financial system.
The Black-Scholes equation allows financial professionals to calculate the value of these financial products, based on the properties of the derivative and the underlying asset.
cboe stock options trader
REUTERS/Frank Polich
Here are some traders in the S&P 500 options pit at the Chicago Board Options Exchange. You won't find a single person here that hasn't heard about the Black-Scholes equation.


Read more: http://www.businessinsider.com/17-equations-that-changed-the-world-2014-3#ixzz2voZ5Hq3k

Monday, March 3, 2014

實用書局

健威 <此時此刻>

說不完的香港故事。

有七十年歷史的實用書局因老闆龍良臣去世,將於六月結業了。讀了新聞,大為詫異:怎麼實用書局還在?

滄海桑田,我以為它一早就消失於時代的波濤中,想不到,它仍在。龍先生跟孫女說:「以前好威水㗎,成條街都是書局。」他說的是文化的集體盛況;那是他那帶鄉音的孫女、也是現在年輕一代沒法想像的——六七十年代,奶路臣街、西洋菜街一帶書店密布;除了書店,還有擺地攤的;而在西洋菜街的實用書局,就是其中頗體面的一間,實用主要賣的是文史哲書籍,店內書籍分類、陳列整齊,跟一般稍混亂的舊書店很不一樣;那時內地文化大革命,焚書坑儒,除了政治宣傳書籍,出版幾近停頓;卻幸而有香港的小型出版社延續一線文化香脈,不斷翻印一些在內地不可能出版的絕版書,這幾家出版社是龍門(司徒華是股東之一)、神州、滙文閣、波文……而實用又是其中之一,其翻印得最多的是,周作人的文集,幾乎沒錯失任何一本;我愛讀周作人,把實用翻版的七八本周作人全都買下了。

龍先生說自己是共產黨的地下黨,他的性格的確有點像,因為他內歛不多言,永遠跟人保持些距離,所以我沒認真跟他說過幾句話;但觀乎他晚年的窘境,又懷疑「地下黨」是不是一種過分的想像——正如七十年代西湖邊上,所有小販工人都有「國安」身份,那恐怕是外圍又外圍,但都可以「國安」稱之。

旺角的文史哲書店到了八十年代都灰飛煙滅,實用也消失了,我以為它早已化成記憶,沒想到,它搬到油麻地一幢亂七八糟、色情場所密布的大廈去,而且苟延了三十年。文化人的堅持真可歌可泣,可悲亦可嘆。說香港沒文化,對得起龍先生嗎?