كلمة في الدقيقة
206
Darsh_KEWAT
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السرعة
CPCT
Our red blood is full of iron. We need iron for growth and for immunity. It is even added to foodstuffs such as cereals to ensure that there is enough of thisnutrient in the diet to prevent iron deficiency. However on a very different scale during the development of life on planet earth over billions of years irondeficiency may have stimulated evolution. According to our new research rising and falling levels of iron on our planet may have enabled complex organismsto evolve from simpler forebears. The terrestrial planets in our solar system have different amounts of iron in their rocky mantles the layer below theoutermost planetary crust. Mantle of the mercury has the least amount of iron. On the other hand the mantle of the mars has the most. This variation is due todifferences in distance from the sun. It is also down to the varying conditions under which the planets initially formed their metallic iron rich cores. Theamount of iron in the mantle regulates several planetary processes including the retention of surface water. And without water life as we know it cannot exist.Astronomical observations of other solar systems may enable estimates of a mantle iron of planets helping to narrow the search for planets capable ofharbouring life. As well as contributing to planetary habitability iron is fundamental for the biochemistry that allows life to happen. Iron has a uniquecombination of properties including the ability to form chemical bonds in multiple orientations and relative ease of gaining or losing one electron. As a resultiron mediates many biochemical processes in cells especially by enabling catalysis a process that speeds up chemical reactions. Metabolic processes that arevital to life such as cellular energy generation rely on iron. In our work we calculated the amount of iron in the seas of the earth over billions of years. We thenconsidered the effect on evolution of enormous amounts of iron falling out of the seas. The initial formative events of geochemistry evolving into biochemistrylife took place more than four billion years ago. And there is a consensus that iron was a pivotal element for this process. The conditions of early earth werevery different to those now. In particular there was almost no oxygen in the atmosphere which meant that iron was easily soluble in water as ferrous iron. Theabundance of nutritious iron in the early seas of the earth had really helped life to evolve. However this ferrous paradise was not to last. The GreatOxygenation Event resulted in the appearance of oxygen in the atmosphere of the earth. It occurred from around two billion years ago. This changed thesurface of earth and caused a profound loss of soluble iron from the upper ocean and surface waters of the planet. A second more recent event calledoxygenation event occurred between eight hundred to five hundred million years ago. This particularly raised oxygen concentrations yet higher. Life haddeveloped and maintains an inescapable dependency on iron. The loss of access to soluble iron had major consequences for the evolution of life on earth.Behaviour that optimised the acquisition and use of iron would have had a clear selective advantage. We can still see this in genetic analysis of infections today.
Cloud computing is the delivery of on demand computing services from applications to storage and processingpower typically over the internet and on a pay as you go basis. Rather than owning their own computinginfrastructure or data centers companies can rent access to anything from applications to storage from a cloudservice provider. One benefit of using cloud computing services is that firms can avoid the upfront cost andcomplexity of owning and maintaining their own IT infrastructure and instead simply pay for what they use whenthey use it. In turn providers of cloud computing services can benefit from significant economies of scale bydelivering the same services to a wide range of customers. Cloud computing services cover a vast range of optionsnow from the basics of storage networking and processing power through to natural language processing andartificial intelligence as well as standard office applications. Pretty much any service that does not require you to bephysically close to the computer hardware that you are using can now be delivered via the cloud. Cloud computingunderpins a vast number of services. That includes consumer services like Gmail or the cloud backup of the photoson your smartphone though to the services which allow large enterprises to host all their data and run all of theirapplications in the cloud. Netflix relies on cloud computing services to run its video streaming service and its otherbusiness systems too and have a number of other organisations. Cloud computing is becoming the default option formany apps software vendors are increasingly offering their applications as services over the internet rather thanstandalone products as they try to switch to a subscription model. However there is a potential downside to cloudcomputing as it can also introduce new costs and new risks for companies. A fundamental concept behind cloudcomputing is that the location of the service and many of the details such as the hardware or operating system onwhich it is running are largely irrelevant to the user. It is with this in mind that the metaphor of the cloud wasborrowed from old telecoms network schematics in which the public telephone network was often represented as acloud to denote that it just did not matter it was just a cloud of stuff. This is an oversimplification of course for manycustomers location of their services and data remains a key issue. Cloud computing as a term has been around sincethe early twenty first century but the concept of computing as a service has been around for much longer time whencomputer bureaus would allow companies to rent time on a mainframe rather than have to buy one themselves.These timesharing services were largely overtaken by the rise of the PC which made owning a computer much moreaffordable and then in turn by the rise of corporate data centres where companies would store vast amounts of data.But the concept of renting access to computing power has resurfaced again and again in the application serviceproviders utility computing and grid computing of the early twenty first century. This was followed by cloudcomputing which really took hold with the emergence of software as a service and hyperscale cloud computingproviders such as Amazon Web Services.