By Nasos Skaltsas and Chris Spiratos (A class)

Before humans milked cows, herded goats or raised hogs, before they written language, before they had permanent homes, and most certainly before they had cats, they had dogs.

Or dogs had them, depending on how anyone views the relationship between humans and dogs. But scientists are still debating exactly when and where the ancient bond originated. And a large new study being run out, with scientists around the world, may soon provide some answers.

Scientists have come up with a broad picture of the origins of dogs. First off, researchers agree that they evolved from ancient wolves. Scientists once thought that some visionary hunter-gatherer nabbed a wolf puppy from its family one day and started raising tamer and tamer wolves. This is oversimplified, of course, but the essence of the idea is that people   bred wolves to become dogs just the way they now breed dogs to be tiny or large, or to herd sheep.

The prevailing opinion now, however, is that this origin story does not pass muster. Wolves are hard to tame, even as puppies and many researchers find it much more logical that dogs, in effect, invented themselves.

By Aggeliki Hala and Thalia Sfaelou (B class)

Global warming is primarily a problem of too much carbon dioxide (CO2) in the atmosphere—which acts as a blanket, trapping heat and warming the planet. As we burn fossil fuels like coal, oil and natural gas for energy or cut down and burn forests to create pastures and plantations, carbon accumulates and overloads our atmosphere. Certain waste management and agricultural practices aggravate the problem by releasing other potent global warming gases, such as methane and nitrous oxide.

The Consequences of a Warming World

Over the last century, global average temperature has increased dangerously. The 2001-2010 decade is the warmest since 1880—the earliest year for which comprehensive global temperature records were available. In fact, nine of the warmest years on record have occurred in just the last 10 years. This warming has been accompanied by a decrease in very cold days and nights and an increase in extremely hot days and warm nights. The continental United States, for example, has seen record daily highs twice as often as record daily lows from 2000 to 2009. While the record shows that some parts of the world are warming faster than others, the long-term global upward trend is unambiguous.

Of course, land and ocean temperature is only one way to measure the effects of climate change. A warming world also has the potential to change rainfall and snow patterns, increase droughts and severe storms, reduce lake ice cover, melt glaciers, increase sea levels, and change plant and animal behavior.

Solutions to global warming

• Greening transportation: The transportation sector’s emissions have increased at a faster rate than any other energy-using sector over the past decade. A variety of solutions are at hand, including improving efficiency (miles per gallon) in all modes of transport, switching to low-carbon fuels, and reducing vehicle miles traveled through smart growth and more efficient mass transportation systems.
• Revving up renewables: Renewable energy sources such as solar, wind, geothermal and bioenergy are available around the world. Multiple studies have shown that renewable energy has the technical potential to meet the vast majority of our energy needs. Renewable technologies can be deployed quickly, are increasingly cost-effective, and create jobs while reducing pollution.
• Managing forests and agriculture: Taken together, tropical deforestation and emissions from agriculture represent nearly 30 percent of the world’s heat-trapping emissions. We can fight global warming by reducing emissions from deforestation and forest degradation and by making our food production practices more sustainable.
• Ensuring sustainable development: The countries of the world—from the most to the least developed—vary dramatically in their contributions to the problem of climate change and in their responsibilities and capacities to confront it. A successful global compact on climate change must include financial assistance from richer countries to poorer countries to help make the transition to low-carbon development pathways and to help adapt to the impacts of climate change.

By Andrew Symeonidis, Michael Tzanatos & Bill Nikos (A class)

Most climate scientists agree that the main cause of the current global warming trend is human expansion of the «greenhouse effect», an effect that occurs when the atmosphere traps heat radiating from the Earth towards space. This happens because certain gases in the atmosphere block heat from escaping. We are going to analyze some of the effects and the consequences below.

First of all, there has been an increase in the number of droughts and floods in the last years and it seems that the increase will be continuous. Extra water vapour in the atmosphere falls again as extra rain, which can cause flooding in other places in the world. When the weather gets warmer, evaporation from both land and sea increases. This can cause drought in areas of the world where the increased evaporation is not compensated for by more precipitation. Also, less ice and snow has been observed compared to some years earlier. This can cause catastrophic results for some areas that are dependent on melted water from mountain areas and they may suffer from drought and lack of domestic water supply.

In addition, another consequence is the more extreme weather incidents and conditions. The warmer climate will probably cause more heat waves, more violent rainfall and also an increase in the number and/or severity of storms. Finally, the sea level is constantly rising. Some Pacific Island nations are expected to be partially or completely submerged by the end of the century. Sea level rises because of melting ice and snow and because of the thermal expansion of the sea (water expands when warmed). Areas that are just above sea level now may become submerged.

To sum up, the greenhouse effect is a phenomenon that can cause serious damage in some domains of life in Earth, but without it, the planet would be a very cold place.

By Vasilis Tsorbatzoglou (B class)

A supernova is the explosion of a star. It is the largest explosion that takes place in space.

 Where Do Supernovas Take Place?

Supernovas are often seen in other galaxies. But supernovas are difficult to see in our own Milky Way galaxy because dust blocks our view. In 1604, Johannes Kepler discovered the last observed supernova in the Milky Way. NASA’s Chandra telescope discovered the  remains of a more recent supernova. It exploded in the Milky Way more than a hundred years ago.

What Causes a Supernova?

A supernova happens where there is a change in the core, or center, of a star. A change can occur in two different ways, with both resulting in a supernova.

The first type of supernova happens in binary star systems. Binary stars are two stars that orbit the same point. One of the stars, a carbon-oxygen white dwarf, steals matter from its companion star. Eventually, the white dwarf accumulates too much matter. Having too much matter causes the star to explode, resulting in a supernova.

 The second type of supernova occurs at the end of a single star’s lifetime. As the star runs out of nuclear fuel, some of its mass flows into its core. Eventually, the core is so heavy that it cannot withstand its own gravitational force. The core collapses, which results in the giant explosion of a supernova. The sun is a single star, but it does not have enough mass to become a supernova.

Why Do Scientists Study Supernovas?

A supernova burns for only a short period of time, but it can tell scientists a lot about the universe.

One kind of supernova has shown scientists that we live in an expanding universe, one that is growing at an ever increasing rate.

Scientists also have determined that supernovas play a key role in distributing elements throughout the universe. When the star explodes, it shoots elements and debris into space. Many of the elements we find here on Earth are made in the core of stars. These elements travel on to form new stars, planets and everything else in the universe.

By Christine Horba and Akrivi Christopoulou (B class)

Dog owners will not be surprised to learn that man’s best friend can tell what mood they are in by looking at their face. A recent study has discovered that dogs look at their owner’s faces for sings of anger, sadness, or happiness in exactly the same way as we do to other people.

The scientists involved in the study believe dogs have developed these face reading skills over thousands of generations as a means of avoiding an unwelcome kick or slap from their owner. Dogs look at the human’s face differently from any other image and the way they process the information that they see is dealt with in the same way a human would deal with it.

Research has revealed that human faces are one-sided when it comes to showing emotion. Feelings such as anger, pleasure, and fright show much more clearly on the right-hand side of our faces than on the left. This is believed to be because the right side of a face is controlled by the left part of the brain, which deals with emotions.

Normally when people meet someone for the first time, they tend to look left and they watch the right-hand side of the face. This is called ‘left-gaze bias’ and has been proved time and time again experiments. It is now believed that dogs do the same thing and look at the right-hand side of their owner’s face.

To carry out the research, scientists showed seventeen dogs pictures of people, other dogs, monkeys, and objects, and filmed the dogs’ head and eye movements. They found that when the dogs looked at pictures of anything but a human, their eyes moved evenly across the picture, but when presented with a picture of a human, their eyes moved to the left, just as a human’s would. No other animal tested has shown this response to pictures of anything, so dogs are unique in this respect.

It was also discovered that dogs look to the left much more when shown a picture of someone who is angry rather than happy or sad. This would suggest that it is important for a dog to work out a human’s mood quickly and accurately when a human is angry, and therefore more likely to hit out at the dog. Surprisingly, when the dogs were shown pictures of an upside-down human face, they still looked to the left, whereas humans lose the left-gaze bias when in the same situation.

By Efthimaki Ioanna (A class)

What are dreams?

Dreams are basically stories and images our mind creates while we sleep. Dreams can be vivid. They can make you feel happy, sad, or scared. And they may seem confusing or perfectly rational.

When dreams occur?

Our sleep is divided into five stages. In the first stage we do not sleep very deeply and we wake up easily. During the following stages our sleep gets deeper and deeper. After the fourth stage REM (Rapid Eye Movement) sleep begins. Most dreaming occurs in this phase. There can be up to seven such REM phases in one night. During this phase our heart rate and breathing gets faster. Blood pressure goes up and the brain starts to work but the body does not. That is why we don’t act out our dreams because the body is inactive.

Theories of Dreaming

There are many theories about why we dream, but no one knows for sure. The most famous expert on dreaming was Sigmund Freud, an Austrian doctor. At the end of the 19th century he found out that a part of our brain is the subconscious. It is a place where we keep our desires and wishes. In dreams we act out these wishes. However, some researchers say dreams have no purpose or meaning and are nonsensical activities of the sleeping brain. They are just strange stories that don’t relate to normal life. Others say dreams are necessary for mental, emotional, and physical health. People often have the same dreams over and over again. They may be events in your life that have caused problems which you have not solved yet.

 Common dreams

Often people report having similar dreams, they are being chased, fall off a cliff, or appear in public naked. These types of dreams are likely caused by a hidden stress or anxiety. While the dreams may be similar, experts say the meaning behind the dream is unique to each person.

Why Do Nightmares Occur?

Nightmares, or bad dreams, are common in children and adults. Often nightmares are caused by:

Stress, conflict, and fear

Trauma

Emotional problems

Medication or drug use

Illness

What Are Lucid Dreams?

Have you ever had a dream where you knew you were dreaming during your dream? This is called a lucid dream. Research has shown that lucid dreaming is accompanied by an increased activation of parts of the brain that are normally suppressed during sleep. Lucid dreaming represents a brain state between REM sleep and being awake.

Some people who are lucid dreamers are able to influence the direction of their dream, changing the story so to speak. While this may be a good tactic to take, especially during a nightmare, many dream experts say it is better to let your dreams occur naturally.

8 Interesting Facts about dreaming

• People forget 90% of their dreams

• Blind people also dream

• In our dreams we only see faces that we already know

• Not everybody dreams in colour

• People can have four to seven dreams in one night.

• Animals Dream Too

• Men and Women Dream Differently

• If you are snoring, then you cannot be dreaming.

 Sources

http://www.webmd.com/sleep-disorders/guide/dreaming-overview

http://www.english-online.at/science/dreaming/dreams-and-how-they-work.htm

http://www.medicalnewstoday.com/articles/297625.php

http://www.boredpanda.com/15-interesting-facts-about-dreams-dreaming/

By Pefanis Dimitris (B class)

It is evident that every person on this Earth has attempted to imagine how our precious planet appears from above. Although we have seen a lot of photos of the Earth taken from space, the image of an earth alone in the inky blackness of space is false. Unfortunately, the picture of a junkyard surrounding the planet is far more real.

There are millions of pieces of rubbish that orbit around earth due to the planet’s gravitational field. Those pieces come from dead spacecraft, usually from inactive and abandoned satellites and space stations. Researchers from NASA suggest that at least 18.000 pieces of debris (10cm minimum) are circling the earth with other items even smaller in size that are not yet classified.

All those debris and items orbit in high velocities (higher than 18.000mph). For that reason, they are a threat to every space mission. Take into consideration that all those pieces are able to tear through space suits, not to mention the damage they can cause to International Space Station or the space shuttle. And of course, the military and commercial flights are also in peril.

In order to deal with this problem the company known as “Star Inc” has introduced the Electrodynamic Debris Eliminator (Edde), funded by the US Defense Advanced Research Projects Agency. It weighs around 100kg and it has nets attached on it that are able to scoop up any piece of junk. According to its designers, a dozen of these craft will take only seven years to remove all 2,465 identified objects over 2kg floating in low-earth orbit. Although it is a quite promising, it is still in experimental face and we are not yet certain of the results.

All in all, space trash is quite an alarming issue that requires attention from all the scientific society. It is certain that if humanity takes the proper measures, this problem will surely be eliminated.

Source:

http://www.theguardian.com/science/2010/aug/22/pollution-litter-space-edde-darpa

By Chrysanthi Manenti, Georgia Katsidima & Bessy Rodopoulou (B class)

Have you ever heard about renewable energy sources? Well if you haven’t, you should know it’s a good way to contribute to the saving of the planet as it can replace conventional fuels in few distinct areas such as electricity generation, wind and air heating or cooling and motor fuels.

First of all, renewable energy is commonly used to refer to the energy that originates from sources which are replenished on a human timescale. Renewable energy might come from sunlight, wind, rain, tides, waves, and geothermal heat but wind, solar and biomass are three main renewable energy sources.

Moreover, solar energy, which relies on the nuclear fusion power from the core of the sun, can be collected and used in many ways. For example, lots of people use solar energy to heat water with solar collectors. As for wind power, wind energy can be used to pump water or generate electricity. Finally, the most modern forms of biomass (the energy from plants are methane generation and alcohol production for automobile fuels.

To sum up, our planet is about to get destructed. That’s why we should adopt an environmental way of thinking and a good way of showing our environmental conscience is using renewable energy. But we have to admit that using renewable energy might be difficult because methods of exploiting these forms of energy are not advanced yet.

By Irene Papapavlou & Hara Hourpiliadi (B class)

The tiger is the largest feline and the third biggest carnivore on earth. It can weigh up to 220-660 pounds while measure to 4-10 feet. Its majestic nature has made it the subject of many myths and traditions around the world. Tigers mainly use their eye sight and hearing to find their pray, they don’t really rely on their sense of smell. Usually the tiger hunts alone by lying in ambush in order to get the benefit of the surprise. In some part of India it is said that the locals would have tiger faces painted on their backs when wondering around the forest. This measure was taken in order to give the impression of staring right at them so that they would prevent attacks from happening. Tigers live solitary lives. Every one of them has its own territory in which they live and hunt until death. The hunt is not always successful, in fact it is estimated that only 1 in 10 attempts will provide food. However they can go several days without food but when the find it they can consume up to 40kg of meat! Unlike most felines, they are admirable swimmers. Tigers can easily swim several kilometers to cross rivers and lakes. They give birth to 2-3 cubs every 2 years, although almost half of them won’t get to live for more than 2 years.

Today the tiger is worldwide threatened with extinction. 97% of its population was lost the past 100 years, while only 3.200 remain in the wild. The dense forests that make up their habitat are vastly disappearing. Large companies buy and clear enormous amounts of tropical land which gives tigers less and less space to live. During the last 10 years their habitats have shrunk by 45%. Nevertheless the greatest yet direct threaten for tigers is illegal wildlife trade. They are poached for their skin as well as body-parts which are used in traditional Asian medicine for their supposedly magic powers. Despite the use being banned, the illegal demand is so high that a dead tiger today can reach 70.000 dollars in Asian markets.

Tigers are both feared and admired by people from all around the globe. To save them we have to protect their natural habitat as well as try to eliminate illegal poaching and trading completely. If we don’t fight for their survival they will become a distant legends and rare zoo sightings.

 Sources:             

Text: http://www.wwf.gr/index.php/en/endangered-species/tiger

Images: https://www.google.gr/search?q=%CF%84%CE%B9%CE%B3%CE%B5%CF%81&safe=active&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiH7I7l0JjKAhUECywKHVnhB_kQ_AUIBygB&biw=1366&bih=653#safe=active&tbm=isch&q=tiger+hd&imgdii=u1IrzxtgZC7u0M%3A%3Bu1IrzxtgZC7u0M%3A%3B3zbN5xR45tHheM%3A&imgrc=u1IrzxtgZC7u0M%3A

https://www.google.gr/search?q=%CF%84%CE%B9%CE%B3%CE%B5%CF%81&safe=active&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiH7I7l0JjKAhUECywKHVnhB_kQ_AUIBygB&biw=1366&bih=653#safe=active&tbm=isch&q=tiger+hd&imgrc=-lr-4Dys4HrZbM%3A

https://www.google.gr/search?q=%CF%84%CE%B9%CE%B3%CE%B5%CF%81&safe=active&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiH7I7l0JjKAhUECywKHVnhB_kQ_AUIBygB&biw=1366&bih=653#safe=active&tbm=isch&q=tiger+swimming&imgdii=c6_jlJ-h0EPe2M%3A%3Bc6_jlJ-h0EPe2M%3A%3BHMfAbi8booJQMM%3A&imgrc=c6_jlJ-h0EPe2M%3A

By Myrsini Hamakioti (B class)

A tornado is a violently rotating column of air that is in contact with both the surface of the earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud. They are often referred to as twisters or cyclones.

The deadliest tornado

 The most deadly tornado known to humankind is the April 26, 1989 Daulatpur-Salturia Tornado. Again, these areas are found in Bangladesh. The already drought-affected areas were smacked by another natural disaster. The estimated size of the tornado according to sources was 1 mile wide. In just a matter of minutes, the horrific twister claimed the lives of 1,300 people and left 12,000 others injured. The towns were completely destroyed and 80,000 were left homeless.

The drought that Bangladesh was experiencing for 6 months intensified the atmospheric conditions, which allowed a deadly massive tornado to form.

 History shows that tornadoes are a natural phenomenon. Elsewhere in the world, countries are not spared from Mother Nature’s wrath. There are places in different countries that have seen and experienced the worst and deadliest in terms of twisters. Due to their regional topography, these areas are hotbeds for tornadoes. This is especially in the country of Bangladesh, which holds the most records of deadly tornadoes.

When Mother Nature strikes, she shows no mercy regardless how high-tech new equipment can be. While disaster preparedness is taught to many, natural disasters like tornadoes can wreck havoc on whatever comes along their path and fatalities often occur.

Sources:

• http://www.therichest.com/expensive-lifestyle/location/top-10-deadliest-tornadoes-in-world-history/?view=all
• https://en.m.wikipedia.org/wiki/Tornado
• http://www.weather.com/storms/tornado/news/deadliest-tornado-world-bangladesh-20140416