Decompression sickness describes a condition arising from dissolved gases coming out of solution into bubbles inside the body on depressurisation. DCS most refers to problems arising from underwater diving decompression, but may be experienced in other depressurisation events such as emerging from a caisson, flying in an unpressurised aircraft at altitude, extravehicular activity from spacecraft. DCS and arterial gas embolism are collectively referred to as decompression illness. Since bubbles can form in or migrate to any part of the body, DCS can produce many symptoms, its effects may vary from joint pain and rashes to paralysis and death. Individual susceptibility can vary from day to day, different individuals under the same conditions may be affected differently or not at all; the classification of types of DCS by its symptoms has evolved since its original description over a hundred years ago. Risk of DCS caused by diving can be managed through proper decompression procedures and contracting it is now uncommon.
Its potential severity has driven much research to prevent it and divers universally use dive tables or dive computers to limit their exposure and to control their ascent speed. If DCS is suspected, it is treated by hyperbaric oxygen therapy in a recompression chamber. If treated early, there is a higher chance of successful recovery. DCS is classified by symptoms; the earliest descriptions of DCS used the terms: "bends" for skeletal pain. In 1960, Golding et al. introduced a simpler classification using the term "Type I" for symptoms involving only the skin, musculoskeletal system, or lymphatic system, "Type II" for symptoms where other organs are involved. Type II DCS is considered more serious and has worse outcomes; this system, with minor modifications, may still be used today. Following changes to treatment methods, this classification is now much less useful in diagnosis, since neurological symptoms may develop after the initial presentation, both Type I and Type II DCS have the same initial management.
The term dysbarism encompasses decompression sickness, arterial gas embolism, barotrauma, whereas decompression sickness and arterial gas embolism are classified together as decompression illness when a precise diagnosis cannot be made. DCS and arterial gas embolism are treated similarly because they are both the result of gas bubbles in the body; the U. S. Navy prescribes identical treatment for arterial gas embolism, their spectra of symptoms overlap, although the symptoms from arterial gas embolism are more severe because they arise from an infarction. While bubbles can form anywhere in the body, DCS is most observed in the shoulders, elbows and ankles. Joint pain accounts for about 60% to 70% of all altitude DCS cases, with the shoulder being the most common site. Neurological symptoms are present in 10% to 15% of DCS cases with headache and visual disturbances being the most common symptom. Skin manifestations are present in about 10% to 15% of cases. Pulmonary DCS is rare in divers and has been observed much less in aviators since the introduction of oxygen pre-breathing protocols.
The table below shows symptoms for different DCS types. The relative frequencies of different symptoms of DCS observed by the U. S. Navy are as follows: Although onset of DCS can occur after a dive, in more than half of all cases symptoms do not begin to appear for at least an hour. In extreme cases, symptoms may occur; the U. S. Navy and Technical Diving International, a leading technical diver training organization, have published a table that documents time to onset of first symptoms; the table does not differentiate between types of symptom. DCS is caused by a reduction in ambient pressure that results in the formation of bubbles of inert gases within tissues of the body, it may happen when leaving a high-pressure environment, ascending from depth, or ascending to altitude. DCS is best known as a diving disorder that affects divers having breathed gas, at a higher pressure than the surface pressure, owing to the pressure of the surrounding water; the risk of DCS increases when diving for extended periods or at greater depth, without ascending and making the decompression stops needed to reduce the excess pressure of inert gases dissolved in the body.
The specific risk factors are not well understood and some divers may be more susceptible than others under identical conditions. DCS has been confirmed in rare cases of breath-holding divers who have made a sequence of many deep dives with short surface intervals. Two principal factors control the risk of a diver suffering DCS: the rate and duration of gas absorption under pressure – the deeper or longer the dive the more gas is absorbed into body tissue in higher concentrations than normal; when the change in pressure causes no immediate symptoms, rapid pressure change can cause permanent bone injury called dysbaric osteonecrosis. DON ca
The Battle of Taranto took place on the night of 11–12 November 1940 during the Second World War between British naval forces, under Admiral Andrew Cunningham, Italian naval forces, under Admiral Inigo Campioni. The Royal Navy launched the first all-aircraft ship-to-ship naval attack in history, employing 21 Fairey Swordfish biplane torpedo bombers from the aircraft carrier HMS Illustrious in the Mediterranean Sea; the attack struck the battle fleet of the Regia Marina at anchor in the harbour of Taranto, using aerial torpedoes despite the shallowness of the water. The success of this attack augured the ascendancy of naval aviation over the big guns of battleships. According to Admiral Cunningham, "Taranto, the night of 11–12 November 1940, should be remembered for as having shown once and for all that in the Fleet Air Arm the Navy has its most devastating weapon." Long before the First World War, the Italian Regia Marina's First Squadron was based at Taranto, a port-city on Italy's south-east coast.
In that period, the British Royal Navy developed plans for countering the power of the Regia Marina. Blunting the power of any adversary in the Mediterranean Sea was an ongoing exercise. Plans for the capture of the port at Taranto were considered as early as the Italian invasion of Abyssinia in 1935. In 1940–41, Italian Army operations in North Africa, based in Libya, required a supply line from Italy; the British Army's North African Campaign, based in Egypt, suffered from much greater supply difficulties. Supply convoys to Egypt had to either cross the Mediterranean via Gibraltar and Malta near the coast of Sicily, or steam around the Cape of Good Hope, up the east coast of Africa, through the Suez Canal to reach Alexandria; the latter was a long and slow route, the Italian fleet was in an excellent position to interdict British supplies and reinforcements using the direct route through the Mediterranean. Following the concept of a fleet in being, the Italians kept their warships in harbour and were unwilling to seek battle with the Royal Navy on their own because any ship lost bigger than a destroyer could not be replaced.
The Italian fleet at Taranto was powerful: six battleships, seven heavy cruisers, two light cruisers and eight destroyers. This made the threat of a sortie against British shipping a serious problem. During the Munich Crisis of 1938, Admiral Sir Dudley Pound, the commander of the British Mediterranean Fleet, was concerned about the survival of the aircraft carrier HMS Glorious in the face of Italian opposition in the Mediterranean, ordered his staff to re-examine all plans for attacking Taranto, he was advised by Lumley Lyster, the captain of Glorious, that his Fairey Swordfish biplane torpedo bombers were capable of a night attack. Indeed, the Fleet Air Arm was the only naval aviation arm with such a capability. Pound ordered training to begin. Security was kept so tight. Just a month before the war began, Pound advised his replacement, Admiral Andrew Cunningham, to consider the possibility; this came to be known as Operation Judgment. The fall of France and the consequent loss of the French fleet in the Mediterranean made redress essential.
The older carrier, HMS Eagle, on Cunningham's strength, was ideal, possessing a experienced air group composed of the obsolescent Swordfish aircraft. Three Sea Gladiator fighters were added for the operation. Firm plans were drawn up after the Italian Army halted at Sidi Barrani, which freed up the British Mediterranean Fleet. Operation Judgment was just a small part of the overarching Operation MB8, it was scheduled to take place on 21 October 1940, Trafalgar Day, but a fire in an auxiliary fuel tank of one Swordfish led to a delay. 60 imp gal auxiliary tanks were fitted in the observer's position on torpedo bombers - the observer taking the air gunner's position - to extend the operating range of the aircraft enough to reach Taranto.) This minor fire spread into something more serious. Eagle suffered a breakdown in her fuel system, so she was eliminated; when the brand-new carrier HMS Illustrious, based at Alexandria, became available in the Mediterranean, she took on board five Swordfish from Eagle and launched the strike alone.
The complete naval task force—commanded by Rear Admiral Lyster, who had originated the plan of attack on Taranto—consisted of Illustrious, the heavy cruisers HMS Berwick and York, the light cruisers HMS Gloucester and Glasgow, the destroyers HMS Hyperion, Ilex and Havelock. The 24 attack Swordfish came from 813, 815, 819, 824 Naval Air Squadrons; the small number of attacking warplanes raised concern that Judgment would only alert and enrage the Italian Navy without achieving any significant results. Illustrious had Fairey Fulmar fighters of 806 Naval Air Squadron aboard to provide air cover for the task force, with radar and fighter control systems. Half of the Swordfish were armed with torpedoes as the primary strike aircraft, with the other half carrying aerial bombs and flares to carry out diversions; these torpedoes were fitted with Duplex magnetic/contact exploders, which were sensitive to rough seas, as the attacks on the German battleship Bismarck showed. There were worries the torpedoes would bottom out in the harbour after being dropped.
The loss rate for the bombers was expected to be fifty percent. Several reconnaissance flights by Martin Marylands of the RAF's No. 431 General Reconnaissance Flight flying from Malta confirmed the location of the Italian fleet. These flights produced photos on which the intelligence officer of Illustrious sp
Miguel de San Román Meza served as the 25th President of Peru for a brief period between 1862 and 1863. In 1822 he participated in the Battle of Ayacucho. From there on, San Román participated in various battles during the first years of the Peruvian republican period, he supported Agustín Gamarra until his defeat in the battle of Ingavi. Despite this defeat, San Román was awarded the grade of Gran Mariscal, he occupied the post of "President of the Council of State" between 1845 and 1849. He served as the President of the National convention from 1855 to 1856. In 1855 he was named Minister of War under Ramón Castilla, served as Prime Minister of Peru from July to October 1858. In 1862 he was elected as the President of Peru. Miguel de San Román introduced the Peruvian Sol currency in 1863 and adopted the decimal system for standard weight and measures, he died a couple of months after assuming power in the Lima district Chorrillos. List of Prime Ministers of Peru List of Presidents of Peru