Inequality math challenge: Solve the problem

MATH CHALLENGE 1. 
if -4≤m≤7 and -3<n<10, what is the maximum possible integer value for m-n?

N.B. Write your answer in comment section. you may also upload the image of solution to the problem.

Do plants poop?: Get your answers

Regard: Grunge

May be sometimes you asked yourself a question like do plants poop? means do plants have excreta or stool like humans and animals? But you did not care of your question. Now It's a spoon feeding answer to your question. Let's see what biologist say about this!

Answer 1: 

It depends on what exactly you mean by “poop.” If you mean solid waste coming out of a hole at the end of a tube just for poop, well, plants obviously don't do that. But pooping is really just a way for our bodies to pump out stuff they can't use, or that might hurt us. And plants totally do that, too!

Answer 2: 

Plants don't have a digestive system, per se. Your (very good) example of a venus fly trap is the closest they come. Carnivorous plants secrete enzymes that slowly breakdown the bugs they trap. when the enzymes break down the bug to its simplest molecules (mostly nitrogen), those molecules are absorbed by the plant. There can be some gunk left in the plant after a bug is digested. Instead of pooping out the waste, that part of the trap will just wither and die as new traps grow.

Answer 3:

Think about it like this: we absorb nutrients from our food with our intestines. We need to eat and digest the food to get it to our intestines, then we need to get rid of the waste to make room for more food. Plants, on the other hand, essentially have their "intestines" on the outsides of their bodies. So they don't need to "eat" or "poop", they just grow their roots into new areas to absorb more nutrients. Plants can sometimes get close to eating and pooping (carnivorous plants). Also, some Halophytes can excrete salt out of their leaves.

Acknowledgment: Real clear science, Reddit

Wolves: Fact and Fiction

Photo: Wolves howling at the moon (itl.cat)

Wolves and Dogs

Wolves are not wild dogs! Although wolves and dogs share a common ancestor and many characteristics, they are classified as different animals: Canis lupus (the gray wolf) and Canis lupus familiaris (the domestic dog). Wolves and dogs each have many subspecies or breeds.

The most important difference between wolves and dogs is that wolves are wild. Kathryn Lord, an evolutionary biologist, says “If you want to socialize a dog with a human or a horse, all you need is 90 minutes to introduce them between the ages of four and eight weeks. After that, a dog will not be afraid of humans or whatever else you introduced. But with a wolf pup, achieving even close to the same fear reduction requires 24-hour contact starting before age three weeks, and even then you won’t get the same attachment or lack of fear.”

Wolves and dogs also have different physical characteristics. Wolves have larger heads, pointier snouts, thicker teeth, and longer legs.

Howling at the Moon

Wolves do not howl at the moon! They howl to communicate with each other. Howling is the most direct way of communicating across long distances, and is especially important in areas where wolf territories are vast. A howl can communicate things like a wolf’s location, warnings about predators, and the position of prey.

Wolves howl for more reasons than we'll ever know. They howl day or night—not just when there is a full moon. They even have daily howling choruses with their own packs, which can be one way of strengthening member bonds. 

The myth that wolves howl at the moon may stem from the fact that ancient people probably ventured outside more often when there was a full moon, since it offers more light for navigating in the dark. Perhaps people simply were more aware of wolf howls on nights will full moons.

Acknowledgment: National geographic

A conceptual assessment of SAU agronomy field crops damage by dust from it's opened southern part

Photo: Dusty leaves (collected)

Background: 

A few minutes earlier, while, I was travelling from Rangpur, my birth place, to Dhaka noticed a huge number of plants leaves fully covered with dust particles formed on road by heavy vehicles running on it. The plants were looking very weird and tired ot being dusty. I asked myself about the effect of dust on photosynthetic activity on these plants. Later on the self-question provoked me to know the details of the effect of dust on photosynthesis. I found lot of works already done on the issue. The findings of the experiment triggered me to think about the crops standing on the SAU agronomy field which are also facing more or less same scenario as roadside plants due to dust spreading from it's opened south side. 

The effect of dust on crop leaves photosynthesis:

Different experiments conducted on the impact of dust particles on photosynthesis showed that dust particles have a significant effect on reducing photosynthetic efficiency of crop plants depending on the thickness of dust on leaves. Even it may result in death of plants on long starvation due to lack of photosynthesis. 

SAU Context:

Therefore, on the basis of the experimental findings, in general, it can be thrust that SAU agronomy field crops are also being hampered by reduced photosynthetic efficiency due to dust spread on leaves from it's southern open part. 

Recommendation: 

Experiments should be carried out on SAU agronomy field crops to assess the effect of dust on photosynthesis. Most probably, so far such kind of experiments are not conducted at SAU. Therefore, there is a good chance of opening a new dimension of research also. 

N.B. this essay was written in a hasty state, any error in writing will be seen as a mistake by chance. 

Brief History of Pet Domestication

Photo: A Pet Cat (P.C.: Pixabay)

The idea that a dog is man’s best friend seems to be a very old concept. In fact, a dog jawbone found in Iraq led scientists to believe that dogs were domesticated over 14,000 years ago. Although wolves are the closest relatives of dogs, scientists are able to distinguish the skeletal elements because wolf heads grow larger through adulthood, whereas that of a dog retains juvenile traits.

Though dogs have been domesticated for a long time, they have undergone many changes since those earliest years, as humans have used selective breeding to create new dog breeds with desired qualities. The Romans preferred colors for their dogs: shepherd’s dogs were bred white so they did not look like wolves at night and farmyard dogs were to be black to scare away thieves. Their shapes have also changed, although smaller-bodied dogs are not a modern invention. There is evidence that a dog similar to the Pekingese, a small, vulnerable dog, lived in China in the 1st century A.D.

Cats are descended from five different types of wildcat, and are thought to have been first domesticated around 7,500 B.C. Whilethey have been used as companions and pets, they have historically also been used for controlling mice and rat infestations. In fact, it is believed that cats may have first encountered humans after they were attracted to rat-infested areas where humans lived.

Though the first evidence of a domesticated cat was found in Cyprus, they are most famous for their role in ancient Egyptian society. Egyptians often mummified cats and placed them in luxurious chambers in the pyramids. There were even three feline goddesses that Egyptians worshipped.

Acknowledgment: Journal of young investigators

Developmental History of Plough

A ploughman with country plough (photo location: Ullagary, Pirganj, Rangpur

Farming is perhaps the oldest industry in the world. Historians are generally in agreement that the earliest implement was probably a crude pointed bent stick or tree branch which was used to stir and break the soil surface. In effect, a hand-held hoe in which the user scratched at the earth to bring nutrients to the surface and let moisture penetrate the soil. This would then produce a suitable tilth and condition in which seeds could be sown.

Existence became closely linked to the success of crops. By cultivating the soil, germination improved, crop yields increased together with crop quality.

Over 4000 years ago, those basic hand-held tools soon developed into simple ‘scratch’ ploughs. These primitive ploughs were pulled by oxen, camels or even elephants and in some instances even their women folk were used. Animals enabled the land to be tilled more easily and faster, subsequently, producing more food for their families. These ‘scratch’ ploughs continued to be used for thousands of years.

The primitive plough made an open shallow furrow, pushing soil away to either side rather than inverting it. The ancient Egyptians made considerable advance in its design. They also succeeded in growing many crop varieties in their dry arid climate by devising complex irrigation systems. As depicted on many of their monuments, the development of the plough from hand-held sticks to implements pulled by animals put them far ahead compared to other civilisations. However, the Greeks and Chinese were not so far behind and further developed the Egyptian ploughs with wheels. These were known as ‘crooked’ ploughs because the beam curved forwards towards the draft animal. The fitment of wheels provided greater control and manoeuvrability. Oak was used for the share beam, elm the draught beam and iron for the shares. Iron at that time was very precious so plough metal would be reshaped into weapons in times of war.

Eventually, the plough was developed to cut a long soil slice and turn it upside down, burying surface residue, conserving moisture, aerating the soil and killing weeds.

The Romans were very efficient with their conquering advances, but their ploughs were simple and crude. Although there had been enormous advances from simple stirring sticks for these early ploughs to produce well tilled soil, the land had to be cross ploughed at right angles to the first operation to ensure all the land was well prepared for sowing. Following the Romans, Anglo-Saxon law required every ploughman to make his own plough and that no one was entitled to use one unless they constructed it themselves.

The origin of the word ‘plough’ is difficult to determine as throughout Europe the spelling is similar - ‘plog’, ‘ploh’, ‘pflug’, ‘ploeg’, ‘plogr’ and old Saxon ’plog’. Ploughs were fastened to draft animals by their horns, tails and later using their shoulders to pull the implement through the soil.

There was little attempt to change the design of the plough until the mid-1600’s with the Dutch being among the first to improve its shape. The change in shape was soon discovered by many, however, in Northern England and Scotland this was further developed. Joseph Foljambe from Rotherham built and patented a plough having what was described as, the perfect implement then in then in u se. Known as the ‘Rotherham Swing Plough’, because no depth wheel was used. It was constructed from a wooden frame with the fittings and coulter made of iron and the mouldboard and share covered with an iron plate. This new design was considered by all who saw it, to be more efficient and lighter to pull than any other kind at that time. For many years this design proved very popular and was used extensively up and down the country. It was perhaps the first to be factory produced on a large scale.

In 1763 a Berwickshire man, John Small, applied mathematical calculations and science to the mouldboard shape. He experimented with varying mouldboard curvatures and patterns, eventually producing a universal cast iron shape that would turn the soil more effectively with less force, wear and strain on the horse and ploughman. Over the years this ‘Scots Plough’ as it was known, was the beginning of the modern mouldboard plough.

Like our ancestors, we used to find improvements. Since the mid 1800’s, there has been enormous change in plough development. Horse ploughs soon became redundant for more efficient steam units with large multi furrow balance ploughs. These ploughs were pulled by cable up and down fields, with only the sound of a steam whistle to indicate a change of ploughing direction.

Using converted horse ploughs, the more manoeuvrable wheeled tractor slowly took over from steam in the early 1900’s and was the start of the modern system we are familiar with today. In the 1920’s when Harry Ferguson’s 3-point linkage appeared it totally revolutionised implement attachment, machine control and performance. This system of attaching an implement to a tractor is now universally used throughout the agricultural industry.

We have witnessed many changes in plough design. For example; in the UK the conventional plough (right hand bodies only) has now been superseded by the reversible plough because of its simplicity of use and the ability to produce level fields. This being an essential part of current farming practices as larger and wider implements are being used. Sprayers, combine and sugar beet harvesters, to name but a few, would not perform to the high standards expected unless the cultivated land was level. Compared to the ploughs being used in the 1950’s and 1960’s we can pick out some major changes in design which have been necessary to cater for the needs and pressures of modern farming.

Acknowledgment: Ploughmen

Sustainable Agriculture in The Desert

Photo: Agriculture in Desert

Organic farming has arrived in Saudi Arabia. But can sustainably produced tomatoes and cucumbers stop the dramatic decline in water reserves on the Arabian Peninsula?

Khalid Al-Haddad is particularly proud of his homemade bread.

Not only is it baked in the in-house oven, but all the ingredients come from his own produce. Al-Haddad is the owner of the "Abazeer" market in the center of Jeddah on the Red Sea, the second largest city in Saudi Arabia. And the shop's assortment is impressive.

"We offer a wide range of organic fruits and organic vegetables," Al-Haddad says. There are also biscuits, spices and even homemade cheese. "And our organic peppermint seems to be a very special offer. We even get orders from Egypt and Lebanon for it."

When Al-Haddad founded his "Abazeer" market in 1985, the Saudi government had just intensified farming in the mostly desert landscape to achieve self-sufficiency in wheat production. Then, at the beginning of the nineties, Saudi Arabia was one of the world's largest exporters of wheat. Quite impressive, considering that less than half a percentage point of the country's area is available for agriculture.

The success, however, came at a price.

It was very hard to turn the fields from sandy soil into fertile land. There were highly inefficient irrigation methods in use, such as giant irrigation systems, where up to half of the sprayed water evaporates before it reaches the ground. The consequences are apparent today. The groundwater level in Saudi Arabia has declined rapidly over the past decades. Many wells have fallen dry, even in fertile areas. The Kingdom has now recognized the problem of water deficiency. King Abdullah, who was in office from 2005 until his death in 2015, made some tentative attempts to convince his countrymen to be more careful with the dwindling water reserves, especially in agriculture. The promotion of particularly water-intensive wheat cultivation is stopped; and there are export stops imposed on other highly water consuming products.

In the Hejaz, the coastal region at the Red Sea, Khalid Al-Haddad runs three large farms. Besides tomatoes and garlic, he also breeds potatoes and beans, cucumbers and zucchini, aubergines, peas and peppers, but also exotic fruits such as papaya, mango, peaches and apricots. His farms have now completely shifted to droplet irrigation. So he spares more than forty percent of water over the irrigation systems, Al-Haddad says.

And that is only the beginning. He started composting the dried-up remains and using them to further fertilize the land. He sows in certain seeding sequences and uses particular nitrogen-binding plant varieties. And of course he refuses to use artificial fertilizers and pesticides, he proudly assures us. All that improves the quality of the soils and thus their water-retaining capacity – at least that's what the German consultants have told him.

The consultants were the experts of the GIZ, the German Association for International Cooperation, who have been on the ground since 2005 on behalf of the Saudi Arabian Agricultural Ministry.

According to Saad Khalil, the Vice Minister of Agriculture, the experience on the organic sector was decisive for choosing the Germans as consultants. "We had to create a reliable legal framework for organic agriculture." In 2011, a Saudi organic seal was introduced. The raw model was the well recognised EU seal. "It is the first of its kind on the Arabian Peninsula," Khalil says.

Currently, 16,000 hectares of land are managed according to the new organic framework, which is almost two per cent of the country's total agricultural area. By 2017, the share should rise to five percent. A realistic goal, taking into account that the royal family has announced to convert the entire production of its huge farms towards organic methods.

"The problem here is that it is not possible to constantly offer organic products all year round," Vice Minister Khalil explains. "It doesn't make sense to take tremendous steps of advertising organic peppers if you can not supply organic peppers for the next six months?" The availability of seed and fertilizers is another problem, according to Khalil. “In the short term, imports can compensate those shortages. The Ministry of Agriculture is already negotiating with potential suppliers from the Mediterranean and the Middle East.”

As of today, there are thirty organic supermarkets throughout the country. And the large conventional supermarkets have started to reserve large parts of their shelves for organic products. Eco food at the stands of the big weekly markets in Riyadh are regularly sold out after just a few hours. Even an organic delivery service is now operating the capital.

It seems as if the kingdom of Saudi Arabia, often critizised for its ruthless approach to religious interpretation and its fixation on oil and other carbon-based fuels production, has taken some important steps towards a more sustainable future

10 facts about plant you'll find interesting

Photo: An emerging seedling

Plants can be dangerous, they’re smarter than we think and there are much more details about plants we don’t know yet – until today. They never disappoint to amaze us human beings. Here you go!

1) 85% of plant life is found in the ocean.

2) Lots of plants are used as dyes. You can colour cloth with stewed onion skin, tea bags or walnut juice. One of the oldest blue dyes comes from a plant called ‘woad’ that has been used since Neolithic times – more than 6,000 years ago.

3) Brazil is named after a tree.

4) Stress relief can be achieved with chemicals in freshly-cut grass, according to scientists.

5) 70,000 plant species are utilized for medicine.

6) 2009 is the year scientists discovered a plant in the Philippines that is capable of devouring rats.

7) More than 20 percent of the world oxygen is produced in the Amazon Rainforest.

8) Dandelion is completely edible, from the petals to the roots.

9) The first certified botanical garden was founded by Pope Nicholas III in the Vatican City in 1278 AD.

10) Trees are the longest-living organisms on earth.

Acknowledgment: Secrets of plants