Wednesday, March 18, 2015
Octopus Predatory Behavior
Having finished the last post with a short discussion of hunting/foraging behavior in the octopus, I figured I should do a lighter post with some fun video examples of cephalopod predatory behavior.
This is a short video of an octopus hunting (I dont know the species) by For the Sea Productions. The octopus catches a fish, apparently by spreading its web and feeling around. Theres some great color-changing behavior here, too. Its hard to know how typical this behavior is, though, as its obviously influenced by the presence of the person filming.
This is a clip from Deep Sea 3D (I think - I havent seen the IMAX film, but thats what the caption says) showing a visually-provoked attack on a crab. I believe that the octopus here is a Pacific giant octopus.
Lets not leave out the other cephalopods! In contrast to octopuses, cuttlefish are primarily visual predators, who shoot out two long tentacles (these are tentacles proper - they are distinct from arms, which octopuses also have) to grab their prey.
This video was made by the California Academy of Sciences, and shows some adorable cuttlefish attacking crabs. Im not sure what species they are. Again, you can see dramatic color changes as the animals become aroused.
This one, also by the CAS, shows a great slow-motion shot of the cuttlefish tentacular strike.
Ill end with one of my favorite videos of cephalopod predation:
Notice how the octopus turns mostly white and spreads its arms when the cuttlefish (most likely Sepia apama, although Im not sure) approaches. This is called the deimatic display, and its a defensive behavior seen in adult octopuses.
I feel obligated to warn anyone reading this that when you search "octopus eating" or similar strings on youtube, you are much more likely to find videos of people eating octopuses than octopuses eating anything. : (
Read more »
This is a short video of an octopus hunting (I dont know the species) by For the Sea Productions. The octopus catches a fish, apparently by spreading its web and feeling around. Theres some great color-changing behavior here, too. Its hard to know how typical this behavior is, though, as its obviously influenced by the presence of the person filming.
This is a clip from Deep Sea 3D (I think - I havent seen the IMAX film, but thats what the caption says) showing a visually-provoked attack on a crab. I believe that the octopus here is a Pacific giant octopus.
Lets not leave out the other cephalopods! In contrast to octopuses, cuttlefish are primarily visual predators, who shoot out two long tentacles (these are tentacles proper - they are distinct from arms, which octopuses also have) to grab their prey.
This video was made by the California Academy of Sciences, and shows some adorable cuttlefish attacking crabs. Im not sure what species they are. Again, you can see dramatic color changes as the animals become aroused.
This one, also by the CAS, shows a great slow-motion shot of the cuttlefish tentacular strike.
Ill end with one of my favorite videos of cephalopod predation:
Notice how the octopus turns mostly white and spreads its arms when the cuttlefish (most likely Sepia apama, although Im not sure) approaches. This is called the deimatic display, and its a defensive behavior seen in adult octopuses.
I feel obligated to warn anyone reading this that when you search "octopus eating" or similar strings on youtube, you are much more likely to find videos of people eating octopuses than octopuses eating anything. : (
Geography some interesting facts!
|
The INTERNET now has a personality. YOURS! See your Yahoo! Homepage.
Labels:
facts!,
geography,
interesting,
some
Measuring Amps What is Measured in Amps
Most electrical appliances have wires attached to them.
The wires carry an electric current around a complete pathway called an electric circuit.
Some appliances need more electric current than others before they will work.
The amount of electric current depends on how much electricity is flowing along the wires.
How can we measure the amount of electric current?
We could try counting the number of electrons that pass along the wire each second.
But this wouldnt be easy!
There are a huge number of electrons traveling along most electric wires.
About 3 million million million electrons flow through a flash bulb every second!
Thats much easier!
Scientists use a special measuring device called an ammeter to measure the electric current.
The ammeter is connected into an electric circuit so that the electrons flowing around the circuit also flow through the ammeter.
Read more »
The wires carry an electric current around a complete pathway called an electric circuit.
Some appliances need more electric current than others before they will work.
The amount of electric current depends on how much electricity is flowing along the wires.
How can we measure the amount of electric current?
We could try counting the number of electrons that pass along the wire each second.
But this wouldnt be easy!
There are a huge number of electrons traveling along most electric wires.
About 3 million million million electrons flow through a flash bulb every second!
To make it easier, we measure the flow of electric current in amperes.
The word ampere comes from the name of the French scientist Andre Ampere, who invented a way of measuring electric current.We usually say amp instead of ampere.
One amp is equal to about 6 million million million electrons every second. So a flashbulb would have a current of half an amp flowing through it.Thats much easier!
Scientists use a special measuring device called an ammeter to measure the electric current.
The ammeter is connected into an electric circuit so that the electrons flowing around the circuit also flow through the ammeter.
Panama Canal What is the Panama Canal
One of the most important construction projects in the history of mankind was the building of the Panama Canal.
The Panama Canal has influenced the development of trade across the globe.
The construction of the canal, shortened the distance between many ports on the Atlantic and Pacific oceans for about 8,000 miles (13,000 kilometers).
According to the first idea, the Panama Canal was supposed to be built by the French at the level of the sea, with depth of 30 feet (9 meters), and width at the bottom of 72 feet (22 meters).
However, the French plan was not realized and in 1904 The United States accepted the construction of the canal.
The French plan to dig a canal below the water level, from one ocean to the other, was dangerous.
In fact, if the differences between high and low tide on one side of the ocean were larger than the other, there would be major currents trough the channel.
This plan also required a lot more digging. Given these problems, it was decided to build a canal with locks, which meant that it must provide water at a higher altitude, in order to meet more parts of the channel.
This has been achieved with the erection of dams on the Chagres River.
Dams form one kind of staircase, through which the ships come into the channel. Ships are raised in some places where the water level is higher, and then descend to the other places.
Almost half of the canal passes through Lake Gatun.
Ships coming from the Atlantic are raised to the level of the lake by 92 feet (28 meters) through a series of three dams. On the other side - Pacific Ocean there is one notch 8 miles (13 kilometers) long. The ships then are being suspended 33 feet (10 meters) in the first dam and 60 feet (18 meters) through two other dams, so go down to sea level. Through the dams the ships are pulled with electric locomotives moving along the coast. Today, trough the dams even the largest ships can move.
Read more »
The Panama Canal has influenced the development of trade across the globe.
The construction of the canal, shortened the distance between many ports on the Atlantic and Pacific oceans for about 8,000 miles (13,000 kilometers).
According to the first idea, the Panama Canal was supposed to be built by the French at the level of the sea, with depth of 30 feet (9 meters), and width at the bottom of 72 feet (22 meters).
However, the French plan was not realized and in 1904 The United States accepted the construction of the canal.
The French plan to dig a canal below the water level, from one ocean to the other, was dangerous.
In fact, if the differences between high and low tide on one side of the ocean were larger than the other, there would be major currents trough the channel.
This plan also required a lot more digging. Given these problems, it was decided to build a canal with locks, which meant that it must provide water at a higher altitude, in order to meet more parts of the channel.
This has been achieved with the erection of dams on the Chagres River.
Dams form one kind of staircase, through which the ships come into the channel. Ships are raised in some places where the water level is higher, and then descend to the other places.
Almost half of the canal passes through Lake Gatun.
Ships coming from the Atlantic are raised to the level of the lake by 92 feet (28 meters) through a series of three dams. On the other side - Pacific Ocean there is one notch 8 miles (13 kilometers) long. The ships then are being suspended 33 feet (10 meters) in the first dam and 60 feet (18 meters) through two other dams, so go down to sea level. Through the dams the ships are pulled with electric locomotives moving along the coast. Today, trough the dams even the largest ships can move.
Story of Vritra
INDRA, the Lord of the three regions, was once so drunk with pride that he quite forgot the courteous manners and forms that the gods had hitherto observed.
When Brihaspati, preceptor of the gods, foremost in all branches of learning, and venerated alike by the gods and the asuras, came to his court, Indra did not rise from his seat to receive the acharya or ask him to be seated and failed to do the customary honors.
In his great conceit, Indra persuaded himself to believe that the sastras allowed him as a king in court the prerogative of receiving guests seated. Brihaspati was hurt by Indras discourtesy and, attributing it to the arrogance of prosperity, silently left the assembly.
Without the high priest of the gods, the court lost in splendor and dignity and became an unimpressive gathering.
Indra soon realized the foolishness of his conduct and, sensing trouble for himself from the acharyas displeasure, he thought to make up with him by falling at his feet and asking for forgiveness.
But this he could not do, because Brihaspati had, in his anger, made himself invisible. This preyed on Indras mind.
With Brihaspati gone, Indras strength began to decline, while that of the asuras increased, which encouraged the latter to attack the gods. Then Brahma, taking pity on the beleaguered gods, advised them to take unto themselves a new acharya.
Said he to them: "You have, through Indras folly, lost Brihaspati. Go now to Twashtas son Visvarupa and request that noble spirit to be your preceptor and all will be well with you."
Heartened by these words, the gods sought the youthful anchorite Visvarupa and made their request to him saying: "Though young in years, you are well versed in the Vedas. Do us the honor of being our teacher."
Visvarupa agreed, to the great advantage of the gods for, as a result of his guidance and teaching, they were saved from the tormenting asuras.
Visvarupas, mother was of the asura clan of daityas, which caused Indra to regard Visvarupa with suspicion. He feared that because of his birth, Visvarupa might not be quite loyal and his suspicion gradually deepened.
Apprehending danger to himself from this descendent of the enemies of the gods, Indra sought to entice him into error with the temptresses of his court and so weaken him spiritually. But Visvarupa did not succumb.
The artful and seductive blandishments of Indras glamour girls had no effect on the young ascetic. He held fast to his vow of celibacy. When Indra found that his plan of seduction failed, he gave way to murderous thoughts and one day killed Visvarupa with the Vajrayudha.
The story goes that the world suffers vicariously for this great sin of Indra. And, as a result of it, parts of the earth turned alkaline and became unsuitable for cultivation and women came to be afflicted with the physical troubles and uncleanness peculiar to them. The frothing of water is also attributed to this.
Twashta in his great rage and grief at Indras cruel killing of his son and, desirous of avenging his death, performed a great sacrifice. And out of the sacrificial flames sprang Indras mortal enemy Vritra.
Twashta sent him against the chief of the gods, saying: "Enemy of Indra, may you be strong and may you kill Indra." A great battle raged between the two in which Vritra was gaining the upper hand.
When the battle was going against Indra, the rishis and the gods sought refuge in great Vishnu who offered them protection and said to them: "Be not afraid. I shall enter Indras Vajrayudha and he will win the battle in the end." And they returned in good heart.
They went to Vritra and said to him: "Please make friends with Indra. You are both equal in strength and valor."
Vritra respectfully answered: "O blameless ones, how can Indra, and I become friends? Forgive me. There cannot be friendship between rivals for supremacy. Two great powers cannot coexist as you know." The rishis said in reply: "Do not entertain such doubts. Two good souls can be friends and their friendship is often after hostility."
Vritra yielded saying: "Well, then, I shall cease fighting. But I have no faith in Indra. He might take me unawares. So I seek this boon of you, namely, that neither by day nor by night, neither with dry weapons nor with wet ones, neither with stone nor with wood, nor with metals, nor with arrows shall Indra be able to take my life."
"So be it," said the rishis and the gods.
Hostilities ceased. But soon Vritras fears were confirmed. Indra only feigned friendship for Vritra but was, all the time, waiting for a suitable opportunity to slay him.
One evening, he met Vritra on the beach and began to attack him in the twilight. The battle had raged for a long while when Vritra praising the Lord Vishnu, said to Indra: "Meanest of the mean, why do you not use the unfailing Vajrayudha? Hallowed by Hari, use it against me and I shall attain blessedness through Hari."
Indra maimed Vritra by chopping off his right arm but, undaunted, the latter hurled with his left band, his iron mace at his assailant who thereupon cut down his other arm also. When Indra disappeared into the mouth of Vritra, great was the consternation of the gods.
But Indra was not dead. He ripped Vritras belly open and issuing forth went to the nearby beach. And directing his thunderbolt at the water hurled it so that the surf flew and hit Vritra. Vishnu having entered the foam, it became a deadly weapon and the mighty Vritra lay dead. The long battle thus ended and the afflicted world heaved a sigh of relief. But to Indra himself, the end of the war brought only ignominy because his victory was secured through sin and deceit and is went into hiding for sheer shame.
Indras disappearance caused the gods and the rishis great distress. For a people without a king or a council of state to govern them cannot prosper. So they went to the good and mighty king Nahusha and offered him the crown.
"Forgive me, I cannot be your king. Who am I to aspire to the seat of Indra? How can I protect you? It is impossible," he humbly objected. But they insisted, saying: "Do not hesitate. Be anointed our king. All the merit and potency of our penance will be yours and be an addition to your strength. The power and the energy of everyone you set your eyes on shall be transferred to you and you will be invincible." Thus over-powered, he agreed. Revolution is no new thing. This story shows that, even in the world of the gods, there was a revolution leading to Indras dethronement and Nahushas installation as king in his stead. The story of Nahushas fall is also instructive. INDRA, the Lord of the three regions, was once so drunk with pride that he quite forgot the courteous manners and forms that the gods had hitherto observed.When Brihaspati, preceptor of the gods, foremost in all branches of learning, and venerated alike by the gods and the asuras, came to his court, Indra did not rise from his seat to receive the acharya or ask him to be seated and failed to do the customary honors.In his great conceit, Indra persuaded himself to believe that the sastras allowed him as a king in court the prerogative of receiving guests seated. Brihaspati was hurt by Indras discourtesy and, attributing it to the arrogance of prosperity, silently left the assembly.Without the high priest of the gods, the court lost in splendor and dignity and became an unimpressive gathering.Indra soon realized the foolishness of his conduct and, sensing trouble for himself from the acharyas displeasure, he thought to make up with him by falling at his feet and asking for forgiveness.But this he could not do, because Brihaspati had, in his anger, made himself invisible. This preyed on Indras mind.With Brihaspati gone, Indras strength began to decline, while that of the asuras increased, which encouraged the latter to attack the gods. Then Brahma, taking pity on the beleaguered gods, advised them to take unto themselves a new acharya.Said he to them: "You have, through Indras folly, lost Brihaspati. Go now to Twashtas son Visvarupa and request that noble spirit to be your preceptor and all will be well with you."Heartened by these words, the gods sought the youthful anchorite Visvarupa and made their request to him saying: "Though young in years, you are well versed in the Vedas. Do us the honor of being our teacher."Visvarupa agreed, to the great advantage of the gods for, as a result of his guidance and teaching, they were saved from the tormenting asuras.Visvarupas, mother was of the asura clan of daityas, which caused Indra to regard Visvarupa with suspicion. He feared that because of his birth, Visvarupa might not be quite loyal and his suspicion gradually deepened.Apprehending danger to himself from this descendent of the enemies of the gods, Indra sought to entice him into error with the temptresses of his court and so weaken him spiritually. But Visvarupa did not succumb.The artful and seductive blandishments of Indras glamour girls had no effect on the young ascetic. He held fast to his vow of celibacy. When Indra found that his plan of seduction failed, he gave way to murderous thoughts and one day killed Visvarupa with the Vajrayudha.The story goes that the world suffers vicariously for this great sin of Indra. And, as a result of it, parts of the earth turned alkaline and became unsuitable for cultivation and women came to be afflicted with the physical troubles and uncleanness peculiar to them. The frothing of water is also attributed to this.Twashta in his great rage and grief at Indras cruel killing of his son and, desirous of avenging his death, performed a great sacrifice. And out of the sacrificial flames sprang Indras mortal enemy Vritra. Twashta sent him against the chief of the gods, saying: "Enemy of Indra, may you be strong and may you kill Indra." A great battle raged between the two in which Vritra was gaining the upper hand. When the battle was going against Indra, the rishis and the gods sought refuge in great Vishnu who offered them protection and said to them: "Be not afraid. I shall enter Indras Vajrayudha and he will win the battle in the end." And they returned in good heart.They went to Vritra and said to him: "Please make friends with Indra. You are both equal in strength and valor."Vritra respectfully answered: "O blameless ones, how can Indra, and I become friends? Forgive me. There cannot be friendship between rivals for supremacy. Two great powers cannot coexist as you know." The rishis said in reply: "Do not entertain such doubts. Two good souls can be friends and their friendship is often after hostility."Vritra yielded saying: "Well, then, I shall cease fighting. But I have no faith in Indra. He might take me unawares. So I seek this boon of you, namely, that neither by day nor by night, neither with dry weapons nor with wet ones, neither with stone nor with wood, nor with metals, nor with arrows shall Indra be able to take my life.""So be it," said the rishis and the gods.Hostilities ceased. But soon Vritras fears were confirmed. Indra only feigned friendship for Vritra but was, all the time, waiting for a suitable opportunity to slay him.One evening, he met Vritra on the beach and began to attack him in the twilight. The battle had raged for a long while when Vritra praising the Lord Vishnu, said to Indra: "Meanest of the mean, why do you not use the unfailing Vajrayudha? Hallowed by Hari, use it against me and I shall attain blessedness through Hari." Indra maimed Vritra by chopping off his right arm but, undaunted, the latter hurled with his left band, his iron mace at his assailant who thereupon cut down his other arm also. When Indra disappeared into the mouth of Vritra, great was the consternation of the gods.But Indra was not dead. He ripped Vritras belly open and issuing forth went to the nearby beach. And directing his thunderbolt at the water hurled it so that the surf flew and hit Vritra. Vishnu having entered the foam, it became a deadly weapon and the mighty Vritra lay dead. The long battle thus ended and the afflicted world heaved a sigh of relief. But to Indra himself, the end of the war brought only ignominy because his victory was secured through sin and deceit and is went into hiding for sheer shame. Indras disappearance caused the gods and the rishis great distress. For a people without a king or a council of state to govern them cannot prosper. So they went to the good and mighty king Nahusha and offered him the crown."Forgive me, I cannot be your king. Who am I to aspire to the seat of Indra? How can I protect you? It is impossible," he humbly objected. But they insisted, saying: "Do not hesitate. Be anointed our king. All the merit and potency of our penance will be yours and be an addition to your strength. The power and the energy of everyone you set your eyes on shall be transferred to you and you will be invincible." Thus over-powered, he agreed. Revolution is no new thing. This story shows that, even in the world of the gods, there was a revolution leading to Indras dethronement and Nahushas installation as king in his stead. The story of Nahushas fall is also instructive.
Jaundice Icterus What is Jaundice
Jaundice (Icterus) is a condition characterized by a yellowing of the skin and the whites of the eyes.
Jaundice is a symptom, not a disease in itself.
The yellow coloration is caused by an excess in the body of the bile pigment bilirubin.
Normally, bilirubin is formed by the breakdown of hemoglobin during the destruction of worn-out red blood cells. It is then excreted by the liver into the bile via the bile ducts.
The liver then can’t excrete bilirubin fast enough.
This occurs in malaria, thalassemia, and hemolytic disease of the newborn.
Jaundice may also result from various diseases that can affect the liver, such as hepatitis, cirrhosis or cancer.
If the bile ducts become blocked, bile can’t be excreted and jaundice occurs.
The ducts may be blocked by inflammation and in fection (cholangitis); a gallstone (cholelithiasis); or cancer of the pancreas or the common bile duct.
Occasionally a drug such as chlorpromazine may inhibit bilirubin excretion by the liver.
In babies, the condition generally disappears within a few days as the enzyme is formed.
Rarely, this enzyme deficiency can also cause jaundice in adults.
In many forms of the condition, bilirubin is excreted in the urine, which becomes dark brown in color.
If the excretion of bile is obstructed, stools are almost white and the digestion of fat is impaired.
If the condition has been present for some time, intense localized itching may occur due to blockage of the bile ducts.
The urine is examined for bilirubin, and the feces for pale coloration (which would indicate an obstruction to bile excretion).
It Is sometimes necessary to perform a liver biopsy to examine Cells under a microscope or to examine the liver, gallbladder, and bile ducts with ultrasound to locate gallstones.
Read more »
Jaundice is a symptom, not a disease in itself.
The yellow coloration is caused by an excess in the body of the bile pigment bilirubin.
Normally, bilirubin is formed by the breakdown of hemoglobin during the destruction of worn-out red blood cells. It is then excreted by the liver into the bile via the bile ducts.
What causes high bilirubin in the body?
High bilirubin can be caused by:- Overproduction of bilirubin;
- Failure of the liver to metabolize bilirubin or to excrete it;
- Blockage of the bile ducts.
The liver then can’t excrete bilirubin fast enough.
This occurs in malaria, thalassemia, and hemolytic disease of the newborn.
Jaundice may also result from various diseases that can affect the liver, such as hepatitis, cirrhosis or cancer.
If the bile ducts become blocked, bile can’t be excreted and jaundice occurs.
The ducts may be blocked by inflammation and in fection (cholangitis); a gallstone (cholelithiasis); or cancer of the pancreas or the common bile duct.
Occasionally a drug such as chlorpromazine may inhibit bilirubin excretion by the liver.
Jaundice in Babies
Mild jaundice occurs as a common and normal condition in newborn babies because at birth there is both a deficiency in the enzyme that helps to excrete bilirubin and also an increased breakdown of red blood cells.In babies, the condition generally disappears within a few days as the enzyme is formed.
Rarely, this enzyme deficiency can also cause jaundice in adults.
Symptoms of Jaundice
Symptoms of Jaundice depend on the specific cause of the jaundice.In many forms of the condition, bilirubin is excreted in the urine, which becomes dark brown in color.
If the excretion of bile is obstructed, stools are almost white and the digestion of fat is impaired.
If the condition has been present for some time, intense localized itching may occur due to blockage of the bile ducts.
How are the causes of jaundice diagnosed?
Diagnosis requires special blood tests, in which a physician determines whether the liver is diseased; whether the bilirubin is being correctly metabolized by the liver cells; and whether there is any abnormal breakdown of the red blood cells.The urine is examined for bilirubin, and the feces for pale coloration (which would indicate an obstruction to bile excretion).
It Is sometimes necessary to perform a liver biopsy to examine Cells under a microscope or to examine the liver, gallbladder, and bile ducts with ultrasound to locate gallstones.
We Are With You A Tribute to all Protestants from Jadavpur University
If it was necessary to brutally,physically attack students of one of the most esteemed universities of India,then we might think of many more things necessary to eradicate the corrupt,insane and maniacal party that is currently residing in this so called system.I have always been maintaining a certain professionalism while writing political,but the limits - every limit has been crossed.And it cannot be accepted anymore.We,students,are disgusted and agitated.How dare the police act like that with the students?This is an universal insult to students.After this,the police will rush in the middle of History Class when school students are reading about Russian Revolution or daring to pronounce the name of any other communist or socialist parties.Or anything they do - perhaps singing inside the campus will be stated not allowed.No one has given any party the monopoly right to convert our prestigious institutions into prison cells.We are not prisoners,we are students.Moreover,forces cannot be allowed like that into a college without proper arrest warrant and the students cannot be carried off in police vans in the middle of the night with no trace of any documentation but harsh voices and boots and brutal attacks.
Is that the way you treat young women?Really?You have no right to physically assault any woman,no matter how big criminals they are.And I do not understand how you pick students up and physically assault them and then do not accept FIRs. What democracy are you talking about?This is not just about SFI. This is not just about Jadavpur University.This is happening everywhere.Today,can someone answer what justice we were able to bring for Sudipto Gupto? This terrorist governance murdered that boy and nothing happened.Simply nothing happened.Just someone lost his life.You are responsible for ending your reign.If you want to know what is going on in West Bengal (if anyone outside India is reading this),please go watch The Great Dictator and I would not have to explain it anymore.
Please Like The Facebook Hokkolorab (These are two Bengali words.Hok means Let it happen and Kolorab means Noise) Page to support us in this protest.The protest is gradually getting internationalised and we hope to gain support from every student with a proper moral base.
Thanks to all of you.Raising your voice is important.No matter how little part of the struggle it gets to be.Millions of droplets will make an ocean.Long Live Revolution!
Disclaimer - The video posted is not owned by me.
WHAT CAUSES GLOBAL WARMING
The world is getting warmer. If you enjoy warm weather, you may think this is good news—but it’s not. Some experts say that over the last hundred years, temperatures on the earth have increased by 2.7 to 10 degrees Fahrenheit (1.5 to 5.6 degrees Celsius).
The earth’s atmosphere is warming up, just as if it was trapped inside a greenhouse. This warming process is often called the greenhouse effect.
The panes of glass in a greenhouse let in light from the sun but trap it when it is released as heat. This makes the climate inside the greenhouse hot.
In a similar way, the earth’s atmosphere lets in sunlight and then traps the heat near the earth’s surface. This is the “greenhouse effect.
But there is another reason why the earth is warming up.
When we burn fuels like coal, oil, gas, or wood, carbon dioxide is released into the atmosphere. Plants use carbon dioxide to help make their food. So tropical rain forests take in large amounts of carbon dioxide from the atmosphere, but at the same time people are cutting down vast areas of these forests.
The earth is warmed by the sun.
Most of the heat is sent back, or radiated, into the atmosphere. Carbon dioxide in the atmosphere traps some of this heat, preventing it from escaping into space. This keeps the earth warm. But if there is too much carbon dioxide in the atmosphere, it will trap too much heat, and the earth’s atmosphere will become too hot.
As the earth’s atmosphere becomes much warmer, the ice in the Arctic and in Antarctica constantly melts. This raises the level of the seas all over the world. A rise of only a few inches could flood many coastlines. Low-lying coastal towns and cities would be endangered by floods, and so would large areas of farmland.
If the seas became warmer, the sea animals and plants would be affected. And many might not be able to survive at all. In other parts of the world, a lack of rain may mean that farmland would become too dry and dusty.
Too much carbon dioxide in the atmosphere prevents more heat than usual from escaping into space. But we still need some heat to keep us warm.
Read more »
The earth’s atmosphere is warming up, just as if it was trapped inside a greenhouse. This warming process is often called the greenhouse effect.
The panes of glass in a greenhouse let in light from the sun but trap it when it is released as heat. This makes the climate inside the greenhouse hot.
In a similar way, the earth’s atmosphere lets in sunlight and then traps the heat near the earth’s surface. This is the “greenhouse effect.
Why is the earth warming up?
More of the sun’s energy is reaching the earth’s atmosphere because the ozone layer is becoming thinner.But there is another reason why the earth is warming up.
When we burn fuels like coal, oil, gas, or wood, carbon dioxide is released into the atmosphere. Plants use carbon dioxide to help make their food. So tropical rain forests take in large amounts of carbon dioxide from the atmosphere, but at the same time people are cutting down vast areas of these forests.
The earth is warmed by the sun.
Most of the heat is sent back, or radiated, into the atmosphere. Carbon dioxide in the atmosphere traps some of this heat, preventing it from escaping into space. This keeps the earth warm. But if there is too much carbon dioxide in the atmosphere, it will trap too much heat, and the earth’s atmosphere will become too hot.
As the earth’s atmosphere becomes much warmer, the ice in the Arctic and in Antarctica constantly melts. This raises the level of the seas all over the world. A rise of only a few inches could flood many coastlines. Low-lying coastal towns and cities would be endangered by floods, and so would large areas of farmland.
If the seas became warmer, the sea animals and plants would be affected. And many might not be able to survive at all. In other parts of the world, a lack of rain may mean that farmland would become too dry and dusty.
Too much carbon dioxide in the atmosphere prevents more heat than usual from escaping into space. But we still need some heat to keep us warm.
The Squid Giant Axon
This post is dedicated to the squid giant axon (not the giant squid axon, although there is presumably a giant squid giant axon – and it’s really big!) These axons carry information to the muscles of a squid’s mantle when it is startled, causing them to contract and jet to safety. These axons are notable because they are so large – up to 1mm in diameter. If this doesn’t seem large to you, consider that typical axons in humans are only a few micrometers in diameter. The squid giant axon is several hundred times larger than the typical human axon. You can see the axon in question in this diagram, labeled “III” (It turns out that the axons commonly studied are the third step in the chain of large axons that carry this specific information; hence they are often referred to as “tertiary giant axons.”)
If you haven’t heard of the squid giant fiber system before, you are probably thinking “So what?” Well, I’ll tell you what. Nowadays, we have technologies that let us interact with various neurons in various ways. For example, we can use tiny glass pipettes to inject current or voltage into a neuron or record its activity. We can use arrays of electrodes to do the same thing with a large population of neurons. These procedures are rather routine in neuroscience, and are done with many different types of neurons in a great variety of animals and specific preparations.
When J. Z. Young was dissecting squid in the 1930’s, however, the techniques available to him were not so refined. He devised a way to isolate a single neuro-muscular unit from the rest of the squids anatomy and manipulate it (see The Function of the Giant Nerve Fibres of the Squid for his description of the procedure – I highly recommend this article, as he’s a great writer and it really is a classic in the history of neuroscience.) Although there were already theories of action potential conduction (notably, Bernstein’s theory that action potentials propagated due to changes in ions flowing across the cell membrane, which turned out to be correct,) Young’s preparation allowed him to directly demonstrate basic properties of single nerve cells. This allowed theories about neuronal function to be empirically tested at a whole new resolution. For example, in the paper cited above, he clearly demonstrates the all-or-none nature of action potentials (that is, when neurons are stimulated, they have a binary response: they either send an action potential down their or they don’t. There are no graded, partial responses.)
Young’s technique opened up the squid giant axon as a model system for many investigators who were trying to understand the behavior of neurons. Notably, Hodkin and Huxley developed a quantitative model of the propagation of action potentials using this preparation, in a famous series of papers that are summarized in A Quantitative Description of the Membrane Curent and its Application to Conduction and Excitation in Nerve. Essentially, the squid giant axon preparation gave researchers an incredible tool, with which they developed the basic models and techniques (for example, the development of voltage clamp by Kenneth Cole in the 1940’s, which allowed the ionic basis of action potentials to be investigated.)
In short, the basic electrophysiological techniques that are in use today almost all stem from Young’s work with the squid giant axon.
On a tangentially related note, Young spent much of the rest of his career trying to convince the scientific community that invertebrates, especially cephalopods, were good model animals with which to study neuroscience. At length, he’s convinced me, as well as (at least some) contemporary scientists, as evidenced by this recent review of the octopus as a model organism for studying memory systems (The Octopus: A Model for a Comparative Analysis of the Evolution of Learning and Memory Mechanisms ).
I have my own ideas about why it’s particularly good to study octopus; but alas, that’s for another post.
My Wish List For Books Summer 2014
MATHS BOOKS
- Tata McGraw-Hills Mathematics for IIT-JEE
SCIENCE BOOKS
- Theoretical Nuclear Physics (Dover Publications)
BENGALI (LITERATURE) BOOKS
- Chin Bharot Long March by Narayan Sanyal
(I could not find out a good photograph of this book.In fact,there was only one photographs which is loosing clarity on stretching to even medium size.This proves the negligence done to Bengali books.Once I get hold of this book,I am definitely going to post detailed photographs.)
- Ami Netajike Dekhechi by Narayan Sanyal
POLITICAL BOOKS
- Best of Maxim Gorky
- Crime and Punishment by Dostoevsky
- Long Walk To Freedom by Nelson Mandela
- Mein Kampf by Adolf Hitler (No,I am not a Nazi and I dont like this maniac who killed thousands of Communists in the concentration camps.Genocide is never a human deed.But I want to know his maniacal attributes or if he had ideas of dictatorship,what were they and why were they so.)
Carbon Prints and Gum Bichromate Prints The Invention of Photography Video Series
Carbon Prints and Gum Bichromate Prints - The Pigment Processes - Invention of Photography 5.44 min video created by George Eastman House.
Carbon prints and gum bichromate prints are both examples of pigment processes. Rather than the metal salts typically used in the formation of photographic images, pigments and bichromated colloids are used in making these prints. A bichromated colloid is a viscous substance such as gelatin or albumen that is made light-sensitive by the addition of a bichromate. Bichromated colloids harden when exposed to light and become insoluble in water; this is the principle behind many of the non-silver-based photographic processes. Pigment processes were developed in the 1850s and offer superior permanence and control of the appearance of the final print. The resulting prints are characterized by broad tones and soft detail, sometimes resembling paintings or drawings.
(This video is made possible by a grant from the U.S. Institute of Museum and Library Services, grant number MA-10-13-0194.)
George Eastman House, an independent nonprofit museum, is an educational institution that tells the story of photography and motion pictures—media that have changed and continue to change our perception of the world.
Read more »
Carbon prints and gum bichromate prints are both examples of pigment processes. Rather than the metal salts typically used in the formation of photographic images, pigments and bichromated colloids are used in making these prints. A bichromated colloid is a viscous substance such as gelatin or albumen that is made light-sensitive by the addition of a bichromate. Bichromated colloids harden when exposed to light and become insoluble in water; this is the principle behind many of the non-silver-based photographic processes. Pigment processes were developed in the 1850s and offer superior permanence and control of the appearance of the final print. The resulting prints are characterized by broad tones and soft detail, sometimes resembling paintings or drawings.
(This video is made possible by a grant from the U.S. Institute of Museum and Library Services, grant number MA-10-13-0194.)
George Eastman House, an independent nonprofit museum, is an educational institution that tells the story of photography and motion pictures—media that have changed and continue to change our perception of the world.
INDIAN ARMY BEACON OF UNITY AND SECULARISM
In all the controversy and disputes over language and faith,
the Indian Army stands in stark contrast as a beacon of what
unity and secularism is all about ....
A slap in the face of all who question interfaith and
religious harmony and a reminder as to what
Secularism truly is
Heres the article sent to me by Colonel Rastogi Colonel Rastogi
Any one more secular than the army?
As a serving army officer, I never stop marvelling at the gullibility of our countrymen
to be provoked with alacrity into virulence in the name of religion.
I have never heard the word secular during all my service -- and yet,
the simple things that are done simply in the army make it appear like an island of
sanity in a sea of hatred.
In the army, each officer identifies with the religion of his troops. In regiments
where the soldiers are from more than one religion, the officers -- and indeed all jawans
attend the weekly religious prayers of all the faiths.
How many times have I trooped out of the battalion mandir and, having worn my shoes,
entered the battalion church next door? A few years ago it all became simpler
-- mandirs, masjids, gurudwars and churches began to share premises all over the army.
It saved us the walk.
Perhaps it is so because the army genuinely believes in two central truths
-- oneness of god and victory in operations.
Both are so sacred we cannot nitpick and question the basics.
In fact, sometimes the army mixes up the two! On a visit to the holy cave at Amarnath
a few years ago I saw a plaque mounted on the side of the hill by a battalion
that had once guarded the annual Yatra.
It said, Best wishes from -....- battalion. Deployed for Operation Amarnath.
On another instance, I remember a commanding officer ordered the battalion maulaviji
to conduct the proceedings of Janamashtmi prayers because the panditji had to
proceed on leave on compassionate grounds. No eyebrows were raised.
It was the most rousing and best-prepared sermon on Lord Krishna I have ever had
the pleasure of listening to.
On the Line of Control, a company of Khemkhani Muslim soldiers replaced a Dogra
battalion. Over the next few days, the post was shelled heavily by Pakistanis,
and there were a few non-fatal casualties.
One day, the junior commissioned officer of the company, Subedar Sarwar Khan
walked up to the company commander Major Sharma and said,
"Sahib, ever since the Dogras left, the mandir has been shut. Why dont you
open it once every evening and do aarti? Why are we displeasing the gods?"
Major Sharma shamefacedly confessed he did not know all the words of the aarti.
Subedar Sarwar went away and that night, huddled over the radio set under a
weak lantern light, painstakingly took down the words of the aarti
from the post of another battalion!
How many of us know that along the entire border with Pakistan, our troops abstain
from alcohol and non-vegetarian food on all Thursdays?
The reason: It is called the Peer day --
essentially a day of religious significance for the Muslims.
In 1984, after Operation Bluestar there was anguish in the Sikh community
over the desecration of the holiest of their shrines.
Some of this anger and hurt was visible in the army too.
I remember the first Sikh festival days after the event -- the number of army personnel
of every religious denomination that thronged the regimental gurudwara of the nearest
Sikh battalion was the largest I had seen. I distinctly remember each officer and soldier
who put his forehead to the ground to pay obeisance appeared to linger just a wee bit
longer than usual. Was I imagining this? I do not think so.
There was that empathy and caring implicit in the quality of the gesture
that appeared to say, "You are hurt and we all understand."
We were deployed on the Line of Control those days. Soon after the news of
disaffection among a small section of Sikh troops was broadcast on the BBC,
Pakistani troops deployed opposite the Sikh battalion yelled across
to express their solidarity with the Sikhs.
The Sikh havildar shouted back that the Pakistanis had better not harbour any wrong
notions. "If you dare move towards this post, we will mow you down."
Finally, a real -- and true -- gem....
Two boys of a Sikh regiment battalion were overheard discussing this
a day before Christmas.
"Why are we having a holiday tomorrow?" asked Sepoy Singh.
"It is Christmas," replied the wiser Naik Singh.
"But what is Christmas?"
"Christmas," replied Naik Singh, with his eyes half shut in reverence
and hands in a spontaneous prayer-clasp, "is the guruparb of the Christians."
God bless our Jawans
Colonel Rastogiji
Its priceless!!! !!!!!!!!! !!!!!
Read more »
the Indian Army stands in stark contrast as a beacon of what
unity and secularism is all about ....
A slap in the face of all who question interfaith and
religious harmony and a reminder as to what
Secularism truly is
Heres the article sent to me by Colonel Rastogi Colonel Rastogi
Any one more secular than the army?
As a serving army officer, I never stop marvelling at the gullibility of our countrymen
to be provoked with alacrity into virulence in the name of religion.
I have never heard the word secular during all my service -- and yet,
the simple things that are done simply in the army make it appear like an island of
sanity in a sea of hatred.
In the army, each officer identifies with the religion of his troops. In regiments
where the soldiers are from more than one religion, the officers -- and indeed all jawans
attend the weekly religious prayers of all the faiths.
How many times have I trooped out of the battalion mandir and, having worn my shoes,
entered the battalion church next door? A few years ago it all became simpler
-- mandirs, masjids, gurudwars and churches began to share premises all over the army.
It saved us the walk.
Perhaps it is so because the army genuinely believes in two central truths
-- oneness of god and victory in operations.
Both are so sacred we cannot nitpick and question the basics.
In fact, sometimes the army mixes up the two! On a visit to the holy cave at Amarnath
a few years ago I saw a plaque mounted on the side of the hill by a battalion
that had once guarded the annual Yatra.
It said, Best wishes from -....- battalion. Deployed for Operation Amarnath.
On another instance, I remember a commanding officer ordered the battalion maulaviji
to conduct the proceedings of Janamashtmi prayers because the panditji had to
proceed on leave on compassionate grounds. No eyebrows were raised.
It was the most rousing and best-prepared sermon on Lord Krishna I have ever had
the pleasure of listening to.
On the Line of Control, a company of Khemkhani Muslim soldiers replaced a Dogra
battalion. Over the next few days, the post was shelled heavily by Pakistanis,
and there were a few non-fatal casualties.
One day, the junior commissioned officer of the company, Subedar Sarwar Khan
walked up to the company commander Major Sharma and said,
"Sahib, ever since the Dogras left, the mandir has been shut. Why dont you
open it once every evening and do aarti? Why are we displeasing the gods?"
Major Sharma shamefacedly confessed he did not know all the words of the aarti.
Subedar Sarwar went away and that night, huddled over the radio set under a
weak lantern light, painstakingly took down the words of the aarti
from the post of another battalion!
How many of us know that along the entire border with Pakistan, our troops abstain
from alcohol and non-vegetarian food on all Thursdays?
The reason: It is called the Peer day --
essentially a day of religious significance for the Muslims.
In 1984, after Operation Bluestar there was anguish in the Sikh community
over the desecration of the holiest of their shrines.
Some of this anger and hurt was visible in the army too.
I remember the first Sikh festival days after the event -- the number of army personnel
of every religious denomination that thronged the regimental gurudwara of the nearest
Sikh battalion was the largest I had seen. I distinctly remember each officer and soldier
who put his forehead to the ground to pay obeisance appeared to linger just a wee bit
longer than usual. Was I imagining this? I do not think so.
There was that empathy and caring implicit in the quality of the gesture
that appeared to say, "You are hurt and we all understand."
We were deployed on the Line of Control those days. Soon after the news of
disaffection among a small section of Sikh troops was broadcast on the BBC,
Pakistani troops deployed opposite the Sikh battalion yelled across
to express their solidarity with the Sikhs.
The Sikh havildar shouted back that the Pakistanis had better not harbour any wrong
notions. "If you dare move towards this post, we will mow you down."
Finally, a real -- and true -- gem....
Two boys of a Sikh regiment battalion were overheard discussing this
a day before Christmas.
"Why are we having a holiday tomorrow?" asked Sepoy Singh.
"It is Christmas," replied the wiser Naik Singh.
"But what is Christmas?"
"Christmas," replied Naik Singh, with his eyes half shut in reverence
and hands in a spontaneous prayer-clasp, "is the guruparb of the Christians."
God bless our Jawans
Colonel Rastogiji
Its priceless!!! !!!!!!!!! !!!!!
Tuesday, March 17, 2015
Information Flow Diagram
Images gallery of information flow diagram
Data flow diagram
A data flow diagram (DFD) is a graphical representation of the "flow" of data through an information system, modeling its process aspects. Often they are a
Introduction to Data Flow Diagram DFDs
In the late 1970s data-flow diagrams (DFDs) were introduced and popularized for structured analysis and design (Gane and
Information flow diagram
An information flow diagram (IFD) is an illustration of information flow throughout an organisation. An IFD shows the relationship between external and internal
Introduction to DFD Data Flow Diagrams SmartDraw Tutorials
Data flow diagrams illustrate how data is processed by a system in terms of inputs and outputs.
What Is a Data Flow Diagram? EzineArticles Submission Submit
Data flow diagram (DFD) with its familiar appearance like mind mappings, is a graphical organizer. From its name, it is used to show and represent the flow
Data Flow Diagram Software Create data flow diagrams rapidly with
Provides some useful data flow diagrams resource such as how to data flow diagram, data flow diagram examples and data flow diagram software.
Data Flow Diagrams Software Engineering Institute
A Data Flow Diagram (DFD) is a concise way of describing the flows of information within a system. As such it is an important method for understanding and
What Is a Data Flow Diagram? eHow
A data flow diagram allows a computer programmer to develop the logic of a particular program she is writing. Other People Are Reading How to Create a Data Flow
Labels:
diagram,
flow,
information
Subscribe to:
Posts (Atom)