Homework - Polaroid camera

Тhe phenomenon of the Polaroid camera

Do you remember these amazing cameras that immediately develop photographs after having pressed the shutter-release button? Apart from a predecessor model from 1860, the first instant camera, as we know it today, was launched in 1947 by the American scientist Edwin Land, the founder of the Polaroid Corporation.

But how does an instant camera function? Does it consist of a mini printer? – There is a simple answer to it: it is a chemical reaction and the secret is in the film. In order to make an immediate photo development possible, the camera is loaded with film packs containing sheets of plastic negatives instead of a usual film. In contrast to regular cameras, this photographic material already contains the necessary chemicals for photo development as its photosensitive layers - developer layer, image layer, timing layer and acid layer - correspond to the negative film. Once you have snapped a picture, the development process is initiated in the form of a chemical reaction under the surface of the silver compounds on the negatives. Then the four layers react in the presence of a reagent (the chemical that triggers the reaction) and the colors that are captured in the silver layers of the negative are produced. When the photograph is ejected, the particles of the chemicals are simultaneously spread and the image is produced. After that the photograph still needs some seconds to fully develop.

That is it! That is the secret of the Polaroid camera. Hopefully your curiosity has been satisfied!

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Introducing my CAJ – viral and bacterial threats

What is a viral infection?                                                                                                              A viral infection is referred to a disease that can be caused by various types of viruses, such as the influenza-virus. These infections can occur in different places in the body. While some are predominantly in the intestine, others prefer the lungs and airways. When you have a viral infection, people usually suffer from fever, diarrhea, shortness of breath and other complaints.

What is a bacterial infection?                                                                                                       A bacterial infection is referred to any type of infection caused by bacteria rather than a virus. Since bacteria are very common in our bodies and in the world around us, only about 1% of bacteria will actually make us sick. Most times, bacterial infections are treated with several kinds of antibiotics, based on the symptoms and the diagnosis.

It can happen at any time that you fall ill because you were infected with bacteria or contracted a virus. Fortunately, in most cases, these viral and bacterial infections are harmless up to a certain stage of disease.  By harmless I mean that these infections can easily be treated, provided that they are detected at an early stage. 

Apart from very common viral and bacterial threats, such as influenza, chicken pox, MRSA and AIDS, there are also some others that appear as an epidemic (frequent appearance of a disease within a particular region or population) or even as an pandemic (frequent appearance of a disease, however, not within a certain region, but spread across countries or continents). Both the bird flu and the mad cow disease serve as well-known example for a pandemic.

CAJ: MERS coronavirus – the danger from the desert

Another viral threat that is currently making trouble is the MERS coronavirus (Middle East respiratory syndrome coronavirus). This virus is very similar to the SARS coronavirus (severe acute respiratory syndrome) and was first identified in Saudi Arabia in 2012. Since then the virus has claimed more than 150 lives, mainly in the Arabian Peninsula and neighboring countries. But suspected cases were also reported in 14 other countries such as Great Britain, the USA, Egypt, Holland etc.

What is the MERS coronavirus?

The virus can cause flu-like symptoms, but also lead to severe pneumonia and kidney failure. Sometimes it doesn’t even cause any symptoms. Therefore, many infected people were only “detected” in the course of a routine examination they had to undergo as they were in contact with other infected people. The two biggest problems: 1) the actual number of people that contracted the virus can’t be calculated. 2) There is NO vaccination or therapy for the virus. Moreover, the mortality rate exceeds 30% which is very high in comparison with the SARS-virus (approximately 10%).

But where does the virus come from?

According to a recent study, the source of pathogens are probably dromedaries. A nationwide examination of blood and fecal samples of these animals showed that three quarters of all Arabian camels are infected with the MERS virus. However, it hasn’t yet been completely explained how and when the pathogens were passed from the dromedaries to humans.

Do we have to fear a pandemic?

In my opinion, the many pilgrims who come to visit the holy places in Mecca, Medina and Jeddah should be aware of the risks of contracting the virus. The best solution would be to see a doctor after their trip.  I think there might be some further cases, but I don’t think that it’s going to result in a pandemic.

CAJ: The EBOLA virus

Most of you may have never heard of this kind of virus before, and so didn’t me. Only a few weeks ago I first heard about it when I was reading a newspaper article.

How dangerous is the Ebola virus?

With a mortality rate of about 90%, the Ebola virus is considered to be one of the most dangerous pathogens. “Luckily” it has only occurred in Africa so far, predominantly in the Republic of the Congo where it was discovered in 1976. In the past few months at least 59 people in Guinea were killed by the highly pathogenic virus. Moreover, six suspected cases were reported in neighboring Liberia, of which five resulted in death.

But how is the virus transmitted and how does it affect the people?

Fruit bats of a certain plant are considered to be the natural host of the virus. But primarily it is transmitted to people from wild animals and then spreads through human-to-human transmission (through blood and other body fluids). Having contracted the virus (the incubation period is typically two days to three weeks), it makes the people very sick within a very short time. The illness is characterized by fever, headache, muscle pain, weakness, sore throat and followed by impaired kidney and liver function and even internal and external bleeding. The patients need intensive supportive care, however, the problem is that, despite intensive research, there is no licensed specific treatment or vaccine available. That’s why Ebola virus outbreaks have a case fatality rate of up to 90%.

Why aren’t there any cases in Europe or on other continents yet?

The answer is simple: Due to the fact that the infected patients get severely ill within a very short time, they “fortunately” aren’t even able to travel to other countries. Thus, the risk of bringing the disease to other continents is very low. Once there has been a suspected case in Canada, but according to the authorities hasn’t been confirmed.

Group work - rate an instructional text

When looking at these instructions, confusion may arise as its elements, namely text passages and illustrations, are combined in a rather chaotic way. Since it is not obvious which picture corresponds to which passage, it is hard to follow all the steps. Furthermore, neither the steps nor the illustrations are numbered and therefore, it is not clear where to start. A good recommendation features not only a list of required components and tools, but also the estimated time required for assembly, which is not the case here. Although the author used the correct way of addressing the reader by using active and imperative language, the building steps are rather vague and contain minimal information. The fact that the text passages are written by hand may irritate and distract the readers and also inhibits their ability to comprehend the instructions. All in all, the quality of it is rather low and thus will not only confuse the readers, but also discourage them from using it. As it lacks the necessary elements of a decent guide, it renders the instructions not very helpful for non-professionals.

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