Monday, 21 October 2013

Cri-du-chat syndrome

What is cri-du-chat syndrome?

Cri-du-chat (cat's cry) syndrome, also known as 5p- (5p minus) syndrome, is a chromosomal condition that results when a piece of chromosome 5 is missing. Infants with this condition often have a high-pitched cry that sounds like that of a cat. The disorder is characterized by intellectual disability and delayed development, small head size (microcephaly), low birth weight, and weak muscle tone (hypotonia) in infancy. Affected individuals also have distinctive facial features, including widely set eyes (hypertelorism), low-set ears, a small jaw, and a rounded face. Some children with cri-du-chat syndrome are born with a heart defect.

How common is cri-du-chat syndrome?

Cri-du-chat syndrome occurs in an estimated 1 in 20,000 to 50,000 newborns. This condition is found in people of all ethnic backgrounds.

What are the genetic changes related to cri-du-chat syndrome?

Cri-du-chat syndrome is caused by a deletion of the end of the short (p) arm of chromosome 5. This chromosomal change is written as 5p-. The size of the deletion varies among affected individuals; studies suggest that larger deletions tend to result in more severe intellectual disability and developmental delay than smaller deletions.
The signs and symptoms of cri-du-chat syndrome are probably related to the loss of multiple genes on the short arm of chromosome 5. Researchers believe that the loss of a specific gene, CTNND2, is associated with severe intellectual disability in some people with this condition. They are working to determine how the loss of other genes in this region contributes to the characteristic features of cri-du-chat syndrome.

Can cri-du-chat syndrome be inherited?

Most cases of cri-du-chat syndrome are not inherited. The deletion occurs most often as a random event during the formation of reproductive cells (eggs or sperm) or in early fetal development. Affected people typically have no history of the disorder in their family.
About 10 percent of people with cri-du-chat syndrome inherit the chromosome abnormality from an unaffected parent. In these cases, the parent carries a chromosomal rearrangement called a balanced translocation, in which no genetic material is gained or lost. Balanced translocations usually do not cause any health problems; however, they can become unbalanced as they are passed to the next generation. Children who inherit an unbalanced translocation can have a chromosomal rearrangement with extra or missing genetic material. Individuals with cri-du-chat syndrome who inherit an unbalanced translocation are missing genetic material from the short arm of chromosome 5, which results in the intellectual disability and health problems characteristic of this disorder.

Where can I find information about diagnosis or management of cri-du-chat syndrome?

These resources address the diagnosis or management of cri-du-chat syndrome and may include treatment providers.
You might also find information on the diagnosis or management of cri-du-chat syndrome in Educational resources and Patient support.
General information about the diagnosis and management of genetic conditions is available in the Handbook. Read more about genetic testing, particularly the difference between clinical tests and research tests.
To locate a healthcare provider, see How can I find a genetics professional in my area? in the Handbook.

Where can I find additional information about cri-du-chat syndrome?

You may find the following resources about cri-du-chat syndrome helpful. These materials are written for the general public.

What other names do people use for cri-du-chat syndrome?

  • cat cry syndrome
  • chromosome 5p- Syndrome
  • 5p deletion syndrome
  • monosomy 5p
  • 5p- syndrome

Where can I find general information about genetic conditions?

The resources on this site should not be used as a substitute for professional medical care or advice.

Shailesh kr shukla

Saturday, 19 October 2013

Medicinal Plants

India has 15 Agroclimatic zones and 17000-18000 species of flowering plants of which 6000-7000 are estimated to have medicinal usage in folk and documented systems of medicine, like Ayurveda, Siddha, Unani and Homoeopathy.  About 960 species of medicinal plants are estimated to be in trade of which 178 species have annual consumption levels in excess of 100 metric tones.

Medicinal plants are not only a major resource base for the traditional medicine & herbal industry but also provide livelihood and health security to a large segment of Indian population.  The domestic trade of the AYUSH industry is of the order of Rs. 80 to 90 billion (1US$ = Rs.50).  The Indian medicinal plants and their products also account of exports in the range of Rs. 10 billion. 

There is global resurgence in traditional and alternative health care systems resulting in world herbal trade which stands at US$ 120 billion and is expected to reach US$ 7 trillion by 2050.  Indian share in the world trade, at present, however, is quite low.

The National Medicinal Plants Board (NMPB) set-up in November 2000 by the Government of India has the primary mandate of coordinating all matters relating to medicinal plants and support policies and programmes for growth of trade, export, conservation and cultivation.  The Board is located in the Department of Ayurveda, Yoga & Naturopathy, Unani, Siddha & Homeopathy (AYUSH) of the Ministry of Health & Family Welfare.

SOME MEDICINAL PLANTS AND THERE USES.Common name: Chameleon Plant, Toningkhok (Manipuri) 
Botanical name: Houttuynia cordata    Family: Saururaceae (lizard-tail family)

Chameleon Plant is a perennial ground cover plant. It is been marketed as a creeping ornamental garden plant, which has heart shaped leaves up to 75 mm long and almost as wide. The leaves are comprised of a mixture of colors from green through yellow to red, the brighter colors being more prominent when grown in full sunlight. The leaves are opposite along thin erect stems which arise from slender rhizomes. The minute flowers are densely clustered on short spikes. At the base of each spike are four white petal-like parts. The leaves of Chameleon Plant are heart-shaped, usually green, but take on various colors like variegated cream, bronze, scarlet, and have a peppery scent when crushed. The leaves make a marvelous flavoring in salads. In Manipur, people love it and consume it in various ways, as salad, also in pakodasCommon name: Shiny Bush, Slate pencil plant, pepper elder, rat's ear, shiny bush, silverbush •Malayalam: Mashitandu chedi • Assamese: Pononoa • Sanskrit: Toyakandha, Varshabhoo 
Botanical name: Peperomia pellucida    Family: Piperaceae (Pepper family)
Synonyms: Peperomia exigua, Peperomia translucens, Piper pellicudum

Shiny bush is a common fleshy annual herb, growing by roadside and in wasteland. Stems are translucent pale green, erect or ascending, usually 15-45 cm long, internodes usually 3-8 cm long, hairless. Fleshy leaves are heart shaped, shiny light green, 1.5-4 cm long, 1-3.3 cm wide. It has very small bi-sexual flowers growing in the form of cord-like spikes, 3-6 cm long, arising from the leaf axils. The fruits are also very small, round to oblong, ridged, first green later black. They have one single seed. Shiny bush has a mustard like odor.The plant can be utilized as a vegetable and in salads. Shiny Bush is native to south America, but widely naturalized and cultivated. 
Common name: Tailed Pepper, java pepper, cubeb • Hindi: कबाब चीनी Kabab-chini, kabachini, शीतल चीनी Sheetal-chini • Kannada: Balmenasu, Gandha menasu • Malayalam: Val-milaku • Marathi: Mothi, Pimpli • Oriya: Sugandhamaricha • Sanskrit: Renuka, cinatiksna, Chinorana, Kakkola • Tamil: valmilaku, kanakamilaku, takkolam • Telugu: halava-miriyalu, toka-miriyalu • Urdu: Kabab-chini, Shital-chini 
Botanical name: Piper cubeba    Family: Piperaceae (Pepper family)

Tailed pepper is a plant cultivated for its fruit and essential oil. It is mostly grown in Java and Sumatra, hence sometimes called Java pepper. It is a perennial plant, with a climbing stem, round branches, about as thick as a goose-quill, ash-colored, and rooting at the joints. The leaves are from 4-6.5 inches long, 1.5-2 inches broad, ovate-oblong, long pointed, and very smooth. Flowers are arranged in narrow spikes at the end of the branches. Fruit, a berry rather longer than that of black pepper. Tailed pepper is native to SE Asia, introduced in India by Arabian traders.
Medicinal uses:  Sanskrit texts included cubeb in various remedies. Charaka and Sushruta prescribed a cubeb paste as a mouthwash, and the use of dried cubebs internally for oral and dental diseases, loss of voice, halitosis, fevers, and cough. Unani physicians use a paste of the cubeb berries externally on male and female genitals to intensify sexual pleasure during coitus. Due to this attributed property, cubeb was called "Habb-ul-Uruus".
Identification credit: Vijayadas D.
Common name: South-Indian Uvaria • Kannada: bugadee balli, bugadee hoo, gunavaara • Malayalam: Narumpanal, Kureel • Marathi: kala-apkara • Sanskrit: Neelavalli, Valeeshakhota • Tamil: puliccan, pulikkan 
Botanical name:  Uvaria narum    Family: Annonaceae (Sugar-apple family)

South-Indian Uvaria is a large woody stellately pubescent straggling shrub with dark bluish green leaves. Leaves are oblong - lanceolate , pointed or long-pointed, hairless on both sides, stalks short, less than 6 mm. Crushed leaves smell like cinnamon. Flowers are reddish, solitary, at branch ends or leaf-opposed, 2.5 cm in diameter. Stamens have anthers concealed by the overlapping connectives. Carpels are numerous , scarlet-red; seeds chestnut brown. South-Indian Uvaria is found in Western ghats from Maharashtra southwards up to an altitude of 1,200 m.
Medicinal uses:  Root and leaves-used in intermittent fevers, biliousness, jaundice; also in rheumatic affections; bruised in salt water, used in skin diseases. A decoction of the root bark is given to women to control fits at the time of delivery.
Identification credit: Asokan Mash

Common name: Sugar Apple, Custard apple • Hindi: Sharifa शरीफ़ा , Sitaphal सीताफल • Manipuri: Sitaphal • Assamese: Katal • Tamil: சீதாபழம் Sitapalam 
Botanical name: Annona squamosa     Family: Annonaceae (sugar apple family)

A small tropical tree, indigenous to the Amazon rainforest, growing up to 20' tall. The leaves are thin, oblong while the flowers are greenish - yellow. Flowers are oblong, 1 to 1 1/2 in long, never fully open, with 1 in long, drooping stalks, and 3 fleshy outer petals, yellow-green on the outside and pale-yellow inside with a purple or dark-red spot at the base. The avoid or conical fruit, with a purple knobby skin, is very sweet and is eaten fresh or can be used for shakes. The fruit is juicy and creamy - white; it may contain up to 40 black seeds. These seeds are poisonous. From delicious fruits of Sitaphal, jelly, jam, conserves, sharbets, syrup, tart and fermented drinks are prepared. The peelings and pulps contain oil that is useful in flavouring.
Medicinal uses:  The bark and leaves contain annonaine, an alkaloid. In tropical 
Common name: Himalayan Marsh Orchid, Marsh Orchis, Spotted Heart Orchid • Kumaon: Hatajari •Kashmiri: Salem Panja • Ladakhi: ཨམབོལཀཔཨ Ambolakpa • Urdu: Salap • Nepali: पाँच आँवले Panch aonle 
Botanical name:  Dactylorhiza hatagirea    Family: Orchidaceae (Orchid family)
Synonyms: Orchis latifolia var. indica

Himalayan Marsh Orchid is a medicinal herb which is now considered critically endangered. It is a perennial herb with erect, leafy, stout and hollow stem. Leaves are oblong-lance-shaped, with sheathing base. Pink purple flowers are borne in an upright spike. Flowers are purple and the bracts green, narrowly lance-shaped, lower longer than the flowers, upper slightly shorter. Flowers are about 1.8 cm long, including the curved spur. Sepals and petals are nearly equal. Three of them form a hood, and the two side sepals spread outwards. The lip is rounded and shallowly 3-lobed, spotted dark purple. Marsh Orchis is found in shrubberies, open slopes and marshes, in the Himalayas, from Pakistan to SE Tibet, at altitudes of 2800-4000 m. Flowering: June-July. Roots are tuberous, divided into 2 or 3 lobes. 

Common name: Fiji Arrowroot, batflower, East Indian arrowroot, Polynesian arrowroot, Tahiti arrowroot • Hindi: बाघ मूंछ Bagh-moochh, देवकन्द devkanda • Marathi: देवकंद devkanda • Tamil: சேனை cenai, ககனம் kakanam, காறாக்கருணை kattu-k-karunai • Telugu: అడవిదుంప adavidumpa 
Botanical name: Tacca leontopetaloides    Family: Dioscoreaceae (Yam family)
Synonyms: Tacca hawaiiensis, Tacca involucrata, Tacca pinnatifida

Fiji Arrowroot is a perennial herb naturally distributed from western Africa through southeast Asia to northern Australia. The leaf's upper surface has depressed veins, and the under surface is shiny with bold yellow veins. Greenish purple flowers are borne on tall stalks in clusters, with long trailing whisker-like bracts. The plant is usually dormant for part of the year and dies down to the ground. Later, new leaves will arise from the round underground tuber. The tubers are hard and potato-like, with a brown skin and white interior. The tubers of Polynesian arrowroot contain starch that was an important food source for many Pacific Island cultures, primarily for the inhabitants of low islands and atolls. Polynesian arrowroot was prepared into a flour to make a variety of puddings. 

Common name: Aloe vera, Medicinal aloe, Burn plant • Hindi: Gheekumari घीकुमारी • Marathi: Khorpad • Tamil: கதலை Kathalai • Malayalam: Chotthu kathalai 
Botanical name: Aloe vera    Family: Asphodelaceae (Aloe family)
Synonyms: Aloe barbadensis, Aloe indica, Aloe vulgaris

Aloe, a popular houseplant, has a long history as a multipurpose folk remedy. Commonly known as Aloe vera, the plant can be snapped off and placed on cuts and burns for immediate relief. Aloe vera is a clump forming succulent whose fleshy gray-green leaves are arranged in a vase shaped rosette atop a very short stem. The leaves are up to 18 in long and 2 in wide at the base, slightly grooved on top, and terminating in a sharp point. The leaves have small grayish teeth on the margins. The main rosette gets up to about 2 ft high, and the plant continually produces little offset rosettes. In winter and spring, medicinal aloe bears small tubular yellow flowers on branched stalks up to 3 ft tall. The real Aloe vera has yellow flowers, but many of the clones available have orange flowers. Although Aloe Vera is a member of the Lily family, it is very-cactus like in its characteristics. 

Common name: Crowfoot Grass, beach wiregrass, coast button grass, comb fringe grass, Duck grass, Durban crowfoot, Egyptian fingergrass, Egyptian grass, finger comb grass, four-finger grass • Hindi: मकड़ा Makra • Manipuri:Pungphai 
Botanical name: Dactyloctenium aegyptium    Family: Poaceae (Grass family)
Synonyms: Eleusine aegyptiaca

Crowfoot Grass is a slender to moderately robust, spreading annual herb, with wiry stems, that bend and root at the lower nodes, with tips that may rise to about 2 ft in height. It is a very common weed of open spaces and wasteland. Leaves are typically grass-like,2-30 cm long, 2-9 mm wide, with blades and sheaths that are without hair. Leaf margins have long, stiff hairs. Flowers arise in 1-7 spikes, 1-6.2 cm long, 3-7 mm wide, at the tip of stems. Seed head resembles a crow's foot, hence the common name. Crowfoot Grass is native to Africa, but naturalized world-wide. 


Friday, 18 October 2013


SQL is a standard language for accessing and manipulating databases.
Abbreviation of structured query language, and pronounced either see-kwellor as separate letters. SQL is a standardized query language for requesting information from a database. The original version called SEQUEL (structuredEnglish query language) was designed by an IBM research center in 1974 and 1975. SQL was first introduced as a commercial database system in 1979 by Oracle Corporation.
Historically, SQL has been the favorite query language for database management systems running on minicomputers and mainframes. Increasingly, however, SQL is being supported by PC database systems because it supports distributed databases (databases that are spread out over several computer systems). This enables several users on a local-area network to access the same database simultaneously.
Although there are different dialects of SQL, it is nevertheless the closest thing to a standard query language that currently exists. In 1986, ANSI approved a rudimentary version of SQL as the official standard, but most versions of SQL since then have included many extensions to the ANSI standard. In 1991, ANSI updated the standard. The new standard is known as SAG SQL.

    What is SQL?

    • SQL stands for Structured Query Language
    • SQL lets you access and manipulate databases
    • SQL is an ANSI (American National Standards Institute) standard

    What Can SQL do?

    • SQL can execute queries against a database
    • SQL can retrieve data from a database
    • SQL can insert records in a database
    • SQL can update records in a database
    • SQL can delete records from a database
    • SQL can create new databases
    • SQL can create new tables in a database
    • SQL can create stored procedures in a database
    • SQL can create views in a database
    • SQL can set permissions on tables, procedures, and views

    SQL is a Standard - BUT....

    Although SQL is an ANSI (American National Standards Institute) standard, there are different versions of the SQL language.
    However, to be compliant with the ANSI standard, they all support at least the major commands (such as SELECT, UPDATE, DELETE, INSERT, WHERE) in a similar manner.


    RDBMS stands for Relational Database Management System.
    RDBMS is the basis for SQL, and for all modern database systems such as MS SQL Server, IBM DB2, Oracle, MySQL, and Microsoft Access.
    The data in RDBMS is stored in database objects called tables.
    A table is a collection of related data entries and it consists of columns and rows.

    SQL Commands


    A database consists of one or more tables. A table is identified by its name. A table is made up of columns and rows. Columns contain the column name and data type. Rows contain the records or data for the columns.

    Basic SQL

    Each record has a unique identifier or primary key. SQL, which stands for Structured Query Language, is used to communicate with a database. Through SQL one can create and delete tables. Here are some commands:
    • CREATE TABLE - creates a new database table
    • ALTER TABLE - alters a database table
    • DROP TABLE - deletes a database table
    • CREATE INDEX - creates an index (search key)
    • DROP INDEX - deletes an index
    SQL also has syntax to update, insert, and delete records.
    • SELECT - get data from a database table
    • UPDATE - change data in a database table
    • DELETE - remove data from a database table
    • INSERT INTO - insert new data in a database table


    The SELECT is used to query the database and retrieve selected data that match the specific criteria that you specify:

    SELECT column1 [, column2, ...]
    FROM tablename
    WHERE condition

    The conditional clause can include these operators
    • = Equal
    • > Greater than
    • < Less than
    • >= Greater than or equal
    • <= Less than or equal
    • <> Not equal to
    • LIKE pattern matching operator
    SELECT * FROM tablename 

    returns all the data from the table.

    Use single quotes around text values (most database systems will also accept double quotes). Numerical values should not be enclosed in quotes.
    LIKE matches a pattern. The wildcard % is used to denote 0 or more characters.
    • 'A%' : matches all strings that start with A
    • '%a' : matches all strings that end with a
    • '%a%' : matches all strings that contain an a


    The CREATE TABLE statement is used to create a new table. The format is:

    CREATE TABLE tablename
    (column1 data type,
    column2 data type,
    column3 data type);
    • char(size): Fixed length character string.
    • varchar(size): Variable-length character string. Max size is specified in parenthesis.
    • number(size): Number value with a max number of columns specified in parenthesis
    • date: Date value
    • number(size,d): A number with a maximum number of digits of "size" and a maximum number of "d" digits to the right of the decimal


    Once a table has been created data can be inserted using INSERT INTO command.

    INSERT INTO tablename
    (col1, ... , coln)
    VALUES (val1, ... , valn)


    To change the data values in a pre existing table, the UPDATE command can be used.

    UPDATE tablename
    SET colX = valX [, colY = valY, ...]
    WHERE condition


    The DELETE command can be used to remove a record(s) from a table.

    DELETE FROM tablename
    WHERE condition

    To delete all the records from a table without deleting the table do

    DELETE * FROM tablename


    To remove an entire table from the database use the DROP command.

    DROP TABLE tablename


    ORDER BY clause can order column name in either ascending (ASC) or descending (DESC) order.

    ORDER BY col_name ASC

    AND / OR

    AND and OR can join two or more conditions in a WHERE clause. AND will return data when all the conditions are true. OR will return data when any one of the conditions is true.


    IN operator is used when you know the exact value you want to return for at least one of the columns

    SELECT * FROM table_name WHERE col_name IN (val1val2, ...)


    The BETWEEN ... AND operator selects a range of data between two values. These values can be numbers, text, or dates.

    SELECT * FROM table_name WHERE col_name BETWEEN val1 AND val2


    There are times when we need to collate data from two or more tables. That is called a join. Tables in a database are related to each other through their keys. We can associate data in various tables without repeating them. For example we could have a table called Customers which could have information about customers like their name, address, phone numbers. We could have another table called Products that has information regarding the products like part number, product name, manufacturer, number in stock, unit price. A third table called Orders could have information regarding what product was ordered, by whom, the date the order was placed, and quantity. Here are the tables:
    01MickeyMouse123 Gouda St.456-7890
    02DonaldDuck325 Eider Ln.786-2365
    2005-2721-680231 Oct 20052
    2005-3420-450102 Nov 20053
    We can obtain information on who has ordered what:

    SELECT Customers.FirstName, Customers.LastName, Products.Name
    FROM Customers, Products, Orders
    WHERE Customers.Cust_ID = Orders.Cust_ID AND Products.Part_No = Orders.Part_No
    We can select data from two tables with INNER JOIN. The INNER JOIN returns all rows from both tables where there is a match. If there are rows in Customers that do not have matches in Orders, those rows will not be listed.
    SELECT Customers.FirstName, Customers.LastName, Orders.Date
    FROM Customers
    INNER JOIN Orders
    ON Customers.Cust_ID = Orders.Cust_ID
    The LEFT JOIN returns all the rows from the first table (Customers), even if there are no matches in the second table (Orders). If there are rows in Customers that do not have matches in Orders, those rows also will be listed.
    SELECT Customers.FirstName, Customers.LastName, Orders.Date
    FROM Customers
    LEFT JOIN Orders
    ON Customers.Cust_ID = Orders.Cust_ID
    The RIGHT JOIN returns all the rows from the second table (Orders), even if there are no matches in the first table (Customers). If there had been any rows in Orders that did not have matches Customers, those rows also would have been listed.
    SELECT Customers.FirstName, Customers.LastName, Orders.Date
    FROM Customers
    RIGHT JOIN Orders
    ON Customers.Cust_ID = Orders.Cust_ID


    With ALTER TABLE you can add or delete columns in an existing table. When you add a column you must specify a data type.
    ALTER TABLE table_name
    ADD col_name datatype

    ALTER TABLE table_name
    DROP COLUMN col_name


    The UNION command is used to select data from two tables very similar to the JOIN command. But the UNION command can be used only with columns having the same datatype. With UNION only distinct values are selected, i.e. if there are common data in the two tables only one instance of that data is returned.

    SELECT Name FROM Customers_USA
    SELECT Name FROM Customers_Asia

    This will select all the customers from USA and Asia but if there is a name that occurs in both the tables it will return only one such name. To get all the names use UNION ALL instead.

    SQL Functions

    There are several built-in functins in SQL. The basic function types are:
    • Aggregate Functions: These are functions that operate against a collection of values, but return a single value.
    • Scalar Functions: These functions operate against a single value, and return a single value.
    To use a built-in function the syntax is: 

    SELECT function (col_name) FROM table_name 


    The GROUP BY was added to SQL so that aggregate functions could return a result grouped by column values.

    SELECT col_name, function (col_name) FROM table_name GROUP BY col_name
    HAVING keyword was introduced because the WHERE keyword could not be used. HAVING states a condition.

    SELECT clo_name, function (col_name) FROM table_name
    GROUP BY col_name
    HAVING function (col_name) condition value


    A view is a virtual table that is a result of SQL SELECT statement. A view contains fields from one or more real tables in the database. This virtual table can then be queried as if it were a real table.

    CREATE VIEW view_name AS
    SELECT col_name(s)
    FROM table_name
    WHERE condition

    A view could be used from inside a query, a stored procedure, or from inside another view. You can add functions and joins to a view and present the data you want to the user.

    Shailesh kr shukla

        Thursday, 17 October 2013

        Earth's Moon: Formation, Composition and Orbit

        The moon is the easiest celestial object to find in the night sky — when it's there. Moon phases and the moon's orbit are a mystery to many. Because it takes 27.3 days both to rotate on its axis and to orbit Earth, the Moon always shows us the same face. We see the Moon because of reflected sunlight. How much of it we see depends on its position in relation to Earth and the Sun.
        Though a satellite of Earth, the Moon is bigger than Pluto. Some scientists think of it as a planet (four other moons in our solar system are even bigger), though that viewpoint has never caught on officially. There are various theories about how the Moon was created, but recent evidence indicates it formed when a huge collision tore a chunk of the Earth away.
        This recent photo of the moon was taken by astronauts on the International Space Station during the Expedition 24 mission mid-2010.

        The moon is Earth's only natural satellite. The moon is a cold, dry orb whose surface is studded with craters and strewn with rocks and dust (called regolith). The moon has no atmosphere. Recent lunar missions indicate that there might be some frozen ice at the poles
        The same side of the moon always faces the Earth. The far side of the moon was first observed by humans in 1959 when the unmanned Soviet Luna 3 mission orbited the moon and photographed it. Neil Armstrong and Buzz Aldrin (on NASA's Apollo 11 mission, which also included Michael Collins) were the first people to walk on the moon, on July 20, 1969. 

        Physical characteristics of Earth's moon

        The leading explanation for how the moon formed was that a giant impact knocked off the raw ingredients for the moon off the primitive molten Earth and into orbit. Scientists have suggested the impactor was roughly 10 percent the mass of Earth, about the size of Mars.
        2.Internal structure
        The moon very likely has a very small core just 1 to 2 percent of the moon's mass and roughly 420 miles (680 km) wide. It likely consists mostly of iron, but may also contain large amounts of sulfur and other elements.
        3.Surface composition
        Like the four inner planets, the moon is rocky. It's pockmarked with craters formed by asteroid impacts millions of years ago. Because there is no weather, the craters have not eroded.
        Atmosphere of the moon
        The moon has a very thin atmosphere, so a layer of dust — or a footprint — can sit undisturbed for centuries. And without much of an atmosphere, heat is not held near the planet, so temperatures vary wildly. Daytime temperatures on the sunny side of the moon reach 273 degrees F; on the dark side it gets as cold as -243.

        Moon Facts

        There are many interesting facts about the moon and trivia that may or may not be important to you. Some interesting facts include:
        • When Alan Sheppard was on the moon, he hit a golf ball and drove it 2,400 feet, nearly one half a mile.
        • In a survey conducted in 1988, 13% of those surveyed believed that the moon is made of cheese.
        • The multi layer space suits worn by the astronauts to the moon weighed 180 pounds on earth, but thirty pounds on the moon due to the lower gravity.
        • How close can you get without completely running out of gas? Apollo 11 had only 20 seconds of fuel left when they landed on the moon.
        • Apollo 15 was the first mission to use a lunar rover. The top speed that was ever recorded in this 4-wheeled land vehicle was 10.56 miles per hour.
        • It is possible to have a month without a full moon. This occurs in February, but either January or March will have two moons.
        • In China, the dark shadows that are on the moon are called "the toad in the moon".
        • The Apollo missions brought back 2196 rock samples weighing 382 kg in total
        Facts About the Moon
        • The moon is not a planet, but a satellite of the Earth.
        • The surface area of the moon is 14,658,000 square miles or 9.4 billion acres
        • Only 59% of the moon's surface is visible from earth.
        • The moon rotates at 10 miles per hour compared to the earth's rotation of 1000 miles per hour.
        • When a month has two full moons, the second full moon is called a blue moon. Another definition of a blue moon is the third full moon in any season (quarter of year) containing 4 total full moons.
        • From Earth, we always see the same side of the moon; the other side is always hidden.
        • The dark spots we see on the moon that create the image of the man in the moon are actually craters filled with basalt, which is a very dense material.
        • The moon is the only extraterrestrial body that has ever been visited by humans. It is also the only body that has had samples taken from it.
        • The first space craft to send back pictures from the moon was Luna 3 (built by the Soviet Union) in October 1959.
        • The moon has no global magnetic field.
        • The moon's diameter is about 1/4 the diameter of the Earth. About 49 moons would fit inside the Earth.

        What is a Super Full Moon?

        The distance of the moon from the Earth varies throughout the month and year. The average distance is about 238,000 miles (382,900 kilometers). The moon's position furthest away from Earth is called “apogee” while its closest approach to Earth is referred to as “perigee”. These events do not regularly coincide with the phases of the moon. However, it can happen that the moon is at perigee during the phase of full moon. This event is referred to as Super Full Moon.

        A super full moon occurs when the moon’s closest approach to the Earth (lunar perigee) coincides with the phase of full moon. When this happens the moon may seem bigger and brighter. However, for the ordinary star-gazer there will be no significant difference.
        10 Need-to-Know Things About Earth's Moon:
        1. If the sun were as tall as a typical front door, Earth would be the size of a nickel and the moon would the size of a green pea.
        2. The moon is Earth's satellite and orbits the Earth at a distance of about 384 thousand km (239 thousand miles) or 0.00257 AU.
          Color image of astronaut walking on the moon.
          Twelve human beings have walked on the moon.
        3. The moon makes a complete orbit around Earth in 27 Earth days and rotates or spins at that same rate, or in that same amount of time. This causes the moon to keep the same side or face towards Earth during the course of its orbit.
        4. The moon is a rocky, solid-surface body, with much of its surface cratered and pitted from impacts.
        5. The moon has a very thin and tenuous (weak) atmosphere, called an exosphere.
        6. The moon has no moons.
        7. The moon has no rings.
        8. More than 100 spacecraft been launched to explore the moon. It is the only celestial a body beyond Earth that has been visited by human beings (The Apollo Program).
        9. The moon's weak atmosphere and its lack of liquid water cannot support life as we know it.
        10. Surface features that create the face known as the "Man in the moon" are impact basins on the moon that are filled with dark basalt rocks.

        shailesh kr shukla

        Standard Units (SI Units)

        The International System of Units (abbreviated SIis the metric system used in science, industry, and medicine.

        Brief history of the SI

        The creation of the decimal Metric System at the time of the French Revolution and the subsequent deposition of two platinum standards representing the meter and the kilogram, on 22 June 1799, in the Archives de la République in Paris can be seen as the first step in the development of the present International System of Units.
        In 1832, Gauss strongly promoted the application of this Metric System, together with the second defined in astronomy, as a coherent system of units for the physical sciences. Gauss was the first to make absolute measurements of the earth’s magnetic force in terms of a decimal system based on the three mechanical units millimeter, gram and second for, respectively, the quantities length, mass and time. In later years, Gauss and Weber extended these measurements to include electrical phenomena
        These applications in the field of electricity and magnetism were further developed in the 1860s under the active leadership of Maxwell and Thomson through the British Association for the Advancement of Science (BAAS). They formulated the requirement for a coherent system of units with base units and derived units. In 1874 the BAAS introduced the CGS system, a three-dimensional coherent unit system based on the three mechanical units centimeter, gram and second, using prefixes ranging from micro to mega to express decimal submultiples and multiples. The following development of physics as an experimental science was largely based on this system.
        The sizes of the coherent CGS units in the fields of electricity and magnetism, proved to be inconvenient so, in the 1880s, the BAAS and the International Electrical Congress, predecessor of the International Electrotechnical Commission (IEC), approved a mutually coherent set of practical units. Among them were the ohm for electrical resistance, the volt for electromotive force, and the ampere for electric current.
        After the establishment of the Meter Convention on May, 20 1875 the CIPM concentrated on the construction of new prototypes taking the meter and kilogram as the base units of length and mass. In 1889 the 1st CGPM sanctioned the international prototypes for the meter and the kilogram. Together with the astronomical second as unit of time, these units constituted a three-dimensional mechanical unit system similar to the CGS system, but with the base units meter, kilogram and second. 
        • No matter what field of science you enter, you will need to take measurements, understand them, communicate them to others, and be able to repeat them. In other words, we all have to speak the same basic language.
        • The ability to obtain accurate measurements and communicate those measurements is a key requirement for progress.
        • These are the seven basic units in the SI system: the kilogram (kg) (mass), the second (s) (time), the Kelvin (K) (temperature),  the ampere (A) (electric current), the mole (mol) (amount of a substance), the candela (cd) (luminous intensity), and the meter (m), (distance).
        The Seven SI Units

        This figure displays the fundamental SI units and the combinations leading to more complex measurement units.

        1. Image of The Seven SI Units

          SI Units

          SI = Système International d'unités
          1. Quantity, Name, Symbol
          2. SI Prefixes
          3. SI Derived Units
          4. cgs Units

          Quantity, Name, Symbol

          metre (meter): m
          (the correct English spelling of the unit is "metre", but the variant "meter" is frequently used in the United States)
          kilogram: kg
          second: s
          electric current
          ampere: A
          thermodynamic temperature
          kelvin: K
          amount of substance
          mole: mol
          luminous intensity
          candela: cd

          SI Derived Units

          (Please note: all units to the right of the slash are actually in the denominator!)
          hertz: Hz = 1/s
          newton: N = m kg/s2
          Pressure, stress
          pascal: Pa = N/m2 = kg/m s2
          Energy, work, quantity of heat
          joule: J = N m = m2 kg/s2
          Power, radiant flux
          watt: W = J/s = m2 kg/s3
          Quantity of electricity, electric charge
          coulomb: C = s A
          Electric potential
          volt: V = W/A = m2 kg/s3 A
          farad: F = C/V = s4 A2/m2 kg
          Electric resistance
          ohm: Omega = V/A = m2 kg/s3 A2
          siemens: S = A/V = s3 A2/m2 kg
          Magnetic flux
          weber: Wb = V s = m2 kg/s2 A
          Magnetic flux density, magnetic induction
          tesla: T = Wb/m2 = kg/s2 A
          henry: H = Wb/A = m2 kg/s2 A2
          Luminous flux
          lumen: lm = cd sr
          lux: lx = lm/m2 = cd sr/m2
          Activity (ionizing radiations)
          becquerel: Bq = 1/s
          Absorbed dose
          gray: Gy = J/kg = m2/s2
          Dynamic viscosity
          pascal second: Pa s = kg/m s
          Moment of force
          metre newton: N m = m2 kg/s2
          Surface tension
          newton per metre: N/m = kg/s2
          Heat flux density, irradiance
          watt per square metre: W/m2 = kg/s3
          Heat capacity, entropy
          joule per kelvin: J/K = m2 kg/s2 K
          Specific heat capacity, specific entropy
          joule per kilogram kelvin: J/kg K = m2/s2 K
          Specific energy
          joule per kilogram: J/kg = m2/s2
          Thermal conductivity
          watt per metre kelvin: W/m K = m kg/s3 K
          Energy density
          joule per cubic metre: J/m3 = kg/m s2
          Electric field strength
          volt per metre: V/m = m kg/s3 A
          Electric charge density
          coulomb per cubic metre: C/m3 = s A/m3
          Electric displacement, electric flux density
          coulomb per square metre: C/m2 = s A/m2
          farad per metre: F/m = s4 A2/m3 kg
          henry per metre: H/m = m kg/s2 A2
          Molar energy
          joule per mole: J/mol = m2 kg/s2 mol
          Molar entropy, molar heat capacity
          joule per mole kelvin: J/mol K = m2 kg/s2 K mol
          Exposure (ionizing radiations)
          coulomb per kilogram: C/kg = s A/kg
          Absorbed dose rate
          gray per second: Gy/s = m2/s3
           The Importance of Standard Units in Everyday Life
          The system of measurements is very important in everyday life . In the past , various systems of measurements were used. For example , length was measured in units like foot , yard , chain and mile . Weight was measured in units like pound , ounce , kati , tahil . 
          :82: Today , many countries in the world use the same units of measurements . We say that they use standard units . The standard units used are the S.I. units .
          :82: Under this system of units , mass is measured in kilograms (kg) and length is measured in metres (m).
          :82: The use of standard units makes it easier for people from different countries to communicate with each other . Furthermore , the use of a standard units means a measurement in that unit has the same value anywhere in the world .

          Shailesh kr shukla