KNOWLEDGE π

      ★★ EVOLUTION   ★★★ Evolution is change in the heritable characteristics of biological populations over successive generations.These characteristics are the expressions of genes that are passed on from parent to offspring during reproduction. Different characteristics tend to exist within any given population as a result of mutation, genetic recombination and other sources of genetic variation. Evolution occurs when evolutionary processes such as natural selection (including sexual selection) and genetic drift act on this variation, resulting in certain characteristics becoming more common or rare within a population. The evolutionary pressures that determine whether a characteristic would be common or rare within a population constantly change, resulting in a change in heritable characteristics arising over successive generations. It is this process of evolution that has given rise to biodiversity at every level of biological organisation, including the le...

  SUBMARINES TECHNOLOGY   Before and during World War II, the primary role of the submarine was anti-surface ship warfare. Submarines would attack either on the surface using deck guns, or submerged using torpedoes. They were particularly effective in sinking Allied transatlantic shipping in both World Wars, and in disrupting Japanese supply routes and naval operations in the Pacific in World War II. Mine-laying submarines were developed in the early part of the 20th century. The facility was used in both World Wars. Submarines were also used for inserting and removing covert agents and military forces in special operations, for intelligence gathering, and to rescue aircrew during air attacks on islands, where the airmen would be told of safe places to crash-land so the submarines could rescue them. Submarines could carry cargo through hostile waters or act as supply vessels for other submarines. Submarines could usually locate and attack other submarines only on the surf...

  HISTORY OF                  SUBMARINE (PART- I)  A submarine (or sub) is a watercraft capable of independent operation underwater.  It differs from a submersible, which has more limited underwater capability. The term is also sometimes used historically or colloquially to refer to remotely operated vehicles and robots, as well as medium-sized or smaller vessels, such as the midget submarine and the wet sub. Submarines are referred to as "boats" rather than "ships" irrespective of their size. Although experimental submarines had been built earlier, submarine design took off during the 19th century, and they were adopted by several navies. They were first widely used during World War I (1914–1918), and are now used in many navies, large and small. Military uses include attacking enemy surface ships (merchant and military) or other submarines, and for aircraft carrier protection, blockade running, nuclear deterrence, reconnaissa...

   AZIZUL KHAN Khan Bahadur Qazi Azizul Haque (1872 – 1935) was a Bengali inventor and police officer in British India, notable for his work with Edward Henry and Hem Chandra Bose in developing the Henry Classification System of fingerprints, which is still in use. Haque provided the mathematical basis for the system. Haque was born in 1872 in the village of Paigram Kasba, Phultala, in the Khulna division of the Bengal Presidency (now in Bangladesh). His parents died in a boat accident when he was young. He left his family home at age 12 and went to Kolkata, where he befriended a family who became impressed with his mathematical skills and arranged for him to get a formal education. Haque studied mathematics and science at Presidency College, Kolkata. In 1892, Edward Henry of the Calcutta Police wrote to the college principal asking for the recommendation of a strong statistics student to help with his fingerprint project, and the principal nominated Haque. Henry recruited Haq...

ঘূর্ণিঝড় নাম করন: ঘূর্ণিঝড় বা ঘূর্ণিবাত্যা হল ক্রান্তীয় অঞ্চলের সমুদ্রে সৃষ্ট বৃষ্টি, বজ্র ও প্রচন্ড ঘূর্ণি বাতাস সংবলিত আবহাওয়ার একটি নিম্ন-চাপ প্রক্রিয়া যা নিরক্ষীয় অঞ্চলে উৎপন্ন তাপকে মেরু অঞ্চলের দিকে প্রবাহিত করে। এই ধরনের ঝড়ে বাতাস প্রবল বেগে ঘুরতে ঘুরতে ছুটে চলে বলে এর নামকরণ হয়েছে ঘূর্ণিঝড়। ঘূর্ণিঝড়ের ঘূর্ণন উত্তর গোলার্ধে ঘড়ির কাঁটার বিপরীত দিকে এবং দক্ষিণ গোলার্ধে ঘড়ির কাঁটার দিকে। ঘূর্ণিঝড় উপকূলে আঘাত হানলে যদিও দুর্যোগের সৃষ্টি হয়, কিন্তু এটি আবহাওয়ার একটি স্বাভাবিক প্রক্রিয়া, যা পৃথিবীতে তাপের ভারসাম্য রক্ষা করে। গড়ে পৃথিবীতে প্রতি বছর প্রায় ৮০ টি ঘূর্ণিঝড় সৃষ্টি হয়। এর অধিকাংশই সমুদ্রে মিলিয়ে যায়, কিন্তু যে অল্প সংখ্যক উপকূলে আঘাত হানে তা অনেক সময় ভয়াবহ ক্ষতি সাধন করে আন্তর্জাতিক নিয়ম অনুসারে যে মহাসাগরে ঘূর্ণিঝড় তৈরি হয়, তার অববাহিকায় থাকা দেশগুলি তার নামকরণ করে। মোট ১১টি সংস্থা ঘূর্ণিঝড়ের নাম ঠিক করে। আবহবিদদের মতে, সাধারণ মানুষের কাছে ঝড় সম্পর্কে তথ্য পৌঁছে দিতে হলে একটা সহজ নাম থাকা দরকারি। তা না হলে একই সময় একই সমুদ্রে একাধিক ঝড় থাকলে চ...

  NANOTECHNOLOGY Nanotechnology,  also shortened to nanotech, is the use of matter on an atomic, molecular, and supramolecular scale for industrial purposes. The earliest, widespread description of nanotechnology referred to the particular technological goal of precisely manipulating atoms and molecules for fabrication of macroscale products, also now referred to as molecular nanotechnology.[1][2] A more generalized description of nanotechnology was subsequently established by the National Nanotechnology Initiative, which defined nanotechnology as the manipulation of matter with at least one dimension sized from 1 to 100 nanometers. This definition reflects the fact that quantum mechanical effects are important at this quantum-realm scale, and so the definition shifted from a particular technological goal to a research category inclusive of all types of research and technologies that deal with the special properties of matter which occur below the given size threshold. It is t...

 In 2010 at The Meeting of the States Parties to the Convention on the Prohibition of the Development, Production and Stockpiling of Bacteriological (Biological) and Toxin Weapons and Their Destruction in Geneva[] the sanitary epidemiological reconnaissance was suggested as well-tested means for enhancing the monitoring of infections and parasitic agents, for the practical implementation of the International Health Regulations (2005). The aim was to prevent and minimize the consequences of natural outbreaks of dangerous infectious diseases as well as the threat of alleged use of biological weapons against BTWC States Parties. Many countries require their active-duty military personnel to get vaccinated for certain diseases that may potentially be used as a bioweapon such as anthrax. Public health and disease surveillance It is important to note that most classical and modern biological weapons' pathogens can be obtained from a plant or an animal which is naturally infected. In the ...