Author Archives: FNM Team

Yarsagumba benefits – yarchagumba, Keeda Jadi medicinal benefits

Yarsagumba has earned name as a traditional herb able to cure many diseases and ailments.

It is scientifically known as Cordyceps sinensis. It is popularly known as yarsagumba, yarchagumba, Keeda Jadi.

It has been used since long as a medicine in the old communities of China, Nepal and India. The beneficial effects of caterpillar fungus have been mentioned in the traditional Chinese and Tibetan medicinal literature. According to that, it acts as a medicine for at least 21 diseases and ailments. These diseases are broadly linked with liver, kidney and heart. In addition it is said to be extremely beneficial in the treatment of infertility.

Yarsagumba benefits

Cordyceps or Yarsagumba and its product have also shown remarkable health benefits on respiratory, nervous, sexual and immunological problems.

Yarsagumba also shows anti-cancer, anti-oxidant, anti-inflammatory and anti-microbial activities.

As per the potential medicinal action of Yarsagumba or Cordyceps, its treatment is beneficial in the following treatment:

  • Yarsagumba or Cordyceps sinensis treatment is most effective in erectile dysfunction and to increase longevity
  • female aphrodisiac, malignant tumor, liver diseases, kidney diseases, low BP and dizziness
  • yarsagumba treats infertility, tuberculosis, bronchitis, cough and cold, Arthritis, jaundice, prostate enlargement, chronic pain, sciatica and backache, diabetes
  • Yarsagumba also treats alcoholic hepatitis, coronary heart disease, rheumatism,

Yarsagumba owes its effectiveness towards the cure of so many diseases to the chemical constituents present in it.

Main constituents of the Yarsagumba extract are cordycepic acid, glutamic acid, amino acids, saccharides and sugar derivatives, sterols, nucleotides and nucleosides, 28 saturated and unsaturated fatty acids and their derivatives, organic aids, Vitamin, B1, B2, B12, E, K and many inorganic elements. These components are believed to be behind its potent anti-cancer, anti-oxidant and anti-inflammatory activities.

Yarsagumba benefits: What are the evidences? 

To investigate the effectiveness of Yarsagumba, a study was conducted in China on mice under laboratory conditions. Mice were given the doses containing yarsagumba orally. It was found that after 3 weeks of yarsagumba (Cordyceps) diet, the mice were able to swim longer as compared to the group of mice on regular diet without yarsagumba.

In mice Yarsagumba acted as tonic for the heart action. It inhibited windpipe constrictions and relaxed contracted vascular smooth muscle. Yarsagumba increased their ability and endurance of exercise.

Another study was conducted to test the effects on physical performance. Yarsagumba diet improved energy metabolism in mice. Researchers found that Yarsagumba formulation enhances lactate clearances. This allows athletes greater anaerobic physical performance.

Owing to its beneficial health effects Yarsagumba is now more expensive than the gold. In 2007 its being sold at the rate of ~108700 US $ (70 Lakhs Indian Rs) per kilogram.

Why USA opted out of Paris Climate Change Agreement?

Donald Trump has always been a very vocal climate change denier. Right from many years before the presidential election – till date he has repeatedly said Climate Change a hoax, a con, a stupid thing, a canard and a manipulation by scientists.

He had said on many occasions that the ‘Global warming concept was created by and for the Chinese in order to make U.S. manufacturing non-competitive’.

In a tweet in 2012 Donald Trump said “Let’s continue to destroy the competitiveness of our factories & manufacturing so we can fight mythical global warming. China is so happy!”

Apparently his opinion and stand on global warming and climate change could not get changed after becoming president.

Why USA opted out of Paris Climate Change Agreement?

Trump could not give any cogent reasons as to Why USA opted out of Paris Climate Change Agreement. Some of his cites reasons have been jobs loss at the coal Industry, financial burden the Paris Agreement imposes on USA and the unfair treatment as compared to China and India

Under Obama administration USA took leadership position during the negotiation of Paris Agreement in 2015 to make sure that the world has a new and ambitious treaty on climate change.

On June 1, 2017 while announcing the withdrawal of USA from the Paris Climate Accord President Trump could not give any cogent reasons as to why USA opted out of Paris Climate Change Agreement? 

Is is certain that he fulfilled the pledge he made during the presidential election campaign to “cancel” the accord.

Given below are some of the most pressing issues Trump feels are against the USA in the Paris accord.

USA does not want to contribute financially or otherwise to the Global Climate Change funding processes under the Protocol.

Trump said that his announcement would end the implementation of carbon reduction targets set under Obama and stall all contributions to the United Nations’ Green Climate Fund as these were “costing the United States a fortune.”

Under UNFCCC, negotiations take place under some guiding principles. One principal is of Common but Differential Responsibility and Related Ability. At the core of it is the fact that the rich and industrialized nations have already emitted their share of CO2.

Due to accumulated emissions  of the past, natural resources have shrinked worldwide. The people in the poor countries are dependent on the natural resources for their livelihood. Hence they have suffered the most.

The Paris Agreement differentiates the poor & developing countries from the developed and rich countries. It offers  some advantage to the poor and developing countries to compensate their loss.

It asks rich countries to provided poor countries low carbon technologies and financial resources.

He said ‘Paris Agreement has placed “draconian” financial burdens on the American people’: Through Green Climate Fund, developed countries are bound to provide 100 billion $ per year support to developing countries every year till 2020. Paris Agreement has extended the duration of this support till 2025.

According to the President it is “Yet another scheme to redistribute wealth out of the United States”.

Donald Trump hinted towards his willingness for renegotiations over the Paris agreement and said “And we will start to renegotiate and we’ll see if there’s a better deal. If we can, great. If we can’t, that’s fine.”

Trumps feel that ‘Paris Agreement is unfair to the USA as it put different level of obligations on it and top polluters like China and India’

The talks under the convention takes into account the historical responsibilities. The country that has emitted more in the past has more responsibility to curb emissions now.

Trump said “As someone who cares deeply about our environment, I cannot in good conscience support a deal which punishes the United States,” And added “The Paris accord is very unfair at the highest level to the United States”.

Clearly Trump wants to completely ignore the historical CO2 emissions of USA which is far more than that of the China and India combined.

USA tops the chart of present level of per capita emissions of the countries. It comes second when total carbon emissions of the country are counted even when the population of China and India are far more than that of USA.

China and India are emerging economies. It means that their historic emissions have been negligible. Per capita emissions of these countries are still low from that of the developed countries.

But they rise in the list of biggest polluters when total emissions of the nations are taken into account because of their population size.

‘The mines are starting to open up’ — ‘American people are at loss because of the jobs lost in the coal sector’:

Paris agreement blocks the development of clean coal in America.

Through this move the severe energy restrictions imposed by the Paris Climate Accord will be removed. Trump wants to revive the country’s recently explored abundant coal energy reserves.

Trump said “The mines are starting to open up. We are having a big opening”. And of course he wants to have full utilization of that.  As per the US president this will provide jobs to the American workers in the coal industry and will fulfill his promise ‘to put American workers first’.

However how many jobs it will create is not clear. Many believe that now the renewable energy sector provides more jobs than the coal sector.

It was not only USA but virtually every nation committed to cut down on greenhouse gases emission sources from burning of fossil fuels.

The move has come as a big setback for the climate change supporters.

USA always remained out of the Kyoto Protocol 1997 as well. Kyoto Protocol is the first international agreement on climate change. The then President of USA George W Bush had refused to sign the pact.

The need for yet another climate change agreement was felt because USA was not happy with the existing one. The result was that a global exercise took place and Paris Agreement came into existence which is more bottom up in its approach than top down as against the Kyoto Protocol.

This time again USA failed to be a part of the international climate Change agreement.


Global Warming Statistics 2017 as Provided by Scientists from NASA

Scientists from NASA’s Goddard Institute for Space Studies (GISS), New York do monthly analysis of the global temperatures. They use the publicly available data from 6,300 meteorological stations located around the world. They also use data from ship- and buoy-based instruments to measure sea surface temperatures and from Antarctic research stations.

Global Warming Statistics 2017 as provided by Scientists from NASA is useful in enhancing knowledge about the trends in global temperatures change.

There are two important factors to look out in the analysis – one is the position of the monthly average temperature of a particular month in the records of last 137 years and second its variation from the mean monthly temperature of 1951-1980 (known as anomaly).

1. Global Average Temperature Anomaly for January 2017 

According to the reports from NASA’s Goddard Institute for Space Studies January 2017 was the third-warmest January on record since the modern record keeping started in 1980.

The slot for the warmest January has been occupied by January 2016. January 2007 has been the second warmest January so far in last 137 years history.  

January 2017 was 0.20 degrees Celsius cooler than the warmest January of 2016. However, when compared with the mean January temperature from 1951-1980, January 2017 was 0.92 degrees Celsius warmer.

 2. Global temperature Anomaly for February 2017

February 2017 has been the second-warmest February on 137 years record. The slot for the warmest February goes to February 2016. The mean temperature of February 2017‘s was 0.20 degrees Celsius cooler than that of February 2016.

However, when compared with mean February temperature from 1951-1980, the temperature of February 2017 was 1.1 degrees Celsius warmer.

3. Global temperature Anomaly for March 2017

Similar to February, March 2017 was recorded as the second-warmest March in 137 years of modern record-keeping.

The top slot for the month of average March temperature also goes to the March 2016. In March 2017 the average temperature was 0.15 degrees Celsius cooler than March 2016.

However, as compared to the Mean March temperature from 1951-1980, the temperature of 2017 was 1.12 degrees Celsius warmer.

 4. Global temperature Anomaly for April 2017

As with the February and March, April 2017 was also recorded as the second-warmest April since the beginning of modern record keeping.  

The record for the warmest April so far goes to April 2016. April 2017 was found to be 0.18 degrees Celsius cooler than April 2016. When compared with the mean April temperature from 1951-1980, April 2016 was found to be 0.88 degrees Celsius warmer.

Based on the availability of additional data, the monthly analyses are sometimes updated and based on the data the above mentioned results are subject to change.

Difference between Paris Agreement and Kyoto Protocol is in the Approach to Achieve the Ultimate Goal of Stabilizing Greenhouse Gases in the Atmosphere

Paris Agreement on Climate Change and Kyoto Protocol share the same goal. It is to restrict the global temperature rise below 2 degree Celsius.

Unprecedented increase in the Greenhouse gas Emissions is being attributed for the global temperature rise. To limit the rising temperature collective actions are required to be taken by all the countries. 

Kyoto Protocol (Treaty) 1997  is the first international agreement to keep the global temperature rise under check. Its commitment period will end in 2020 and from onward the Paris Agreement on Climate Change 2015 will come into effect.  Both the Kyoto Protocol and Paris Agreement took place under the United Nations Framework Convention on Climate Change (UNFCCC).

Difference between Paris Agreement and Kyoto ProtocolIn order to understand the key difference between Paris Agreement and Kyoto Protocol it is important to understand that different countries emit different amount of Greenhouse gases (GHG’s). The GHG emissions of  the past is called historical emissions. The historical emissions of different countries have also been very different. This means that each country has contributed differently towards the present global temperature rise. Therefore, it is logical that the efforts by different countries to reduce emissions and adapt to the climatic changes should also be in tune with their emission levels.

The United Nations provide a platform to discuss and decide ‘who’ will do ‘what’. These international treaties set targets for different category of nations to combat climate change.

The Paris Agreement and Kyoto Protocol differs in their approach to achieve the ultimate goal of stabilizing Greenhouse Gases in the atmosphere and keeping the temperature rise below 2 degree C. The difference is in the way these treaties make developed and developing countries commit to take actions to combat climate change.

Kyoto protocol legally binds developed countries to reduce their emissions. These countries are listed in the Annex I of the UNFCCC. During the first commitment period of Kyoto protocol (2008-2012), the developed countries were required to reduce their emissions by 5% below the 1990 level.

During the present second commitment period of the Kyoto protocol which spans between 2013-2010 these nations are required to reduce the emissions by 18%. 

Kyoto protocol does not bind developing countries to cut down their GHG emissions.

Thus, Kyoto protocol maintains strict difference between the developed and the developing nations in terms of emission reduction targets.

The reduction targets under the Kyoto Protocol now covers only 15% of the total emissions worldwide. The reason is that the USA did not participate in the Kyoto protocol, a few countries opted out of it for the second commitment period and some could not achieve their targets.

Paris agreement on climate change attempts to blur the divide between the developed and the developing nations. It made all the nations under UNFCCC to voluntarily commit on their own domestic emission reduction targets.

Paris agreement was agreed (adopted) by 195 nations in Paris during the 21st Conference of Parties (COP21). The efforts to make the countries commit on emission reductions started long before the 21st meeting of COP.

The Conference of Parties 19 (COP19) held in Warsaw (2013) asked all the countries to submit their national pledges to reduce emissions and other plans to combat the adverse effects of climate change. These were called Intended Nationally Determined Contributors (INDC).

Before the Paris conference 180 countries communicated their emission reduction targets to the UNFCCC. These countries collectively emit 90% of the total emissions worldwide.

It is clear that that contrary to Kyoto protocol that makes smaller fraction of emitter countries reduce their emissions, Paris climate agreement can make maximum emitters reduce their emissions. However, in this effort of emission reduction Paris agreement asks developed countries to take the lead.

While the approach adopted by Kyoto protocol was top down in terms of emission reduction targets, in Paris agreement it is the countries that have decided internally (national pledges) how much emissions they aim to reduce. This makes the Paris Agreement’s approach more bottom up.

Where is World’s largest Solar Power Plant located?

The World’s largest Solar Power Plant has been installed in Kurnool district of Andhra Pradesh, India. It is world’s largest solar power plant at any single location. Read below to know 8 very interesting facts about Kurnool Ultra Mega Solar Park.

Where is World's largest Solar Power Plant located

World’s largest solar power plant is in Andhra Pradesh, India Photo Credit

Facts about World’s largest Solar Power Plant

1. The Kurnool Ultra Mega Solar Park will become fully operation by the end of May 2017. When running at its optimum capacity it will generate 1,000 megawatts (1 gigawatt) electricity. As of now its producing 90% of the installed capacity i.e. 900 MW.


2. Although its generating 90% of its total production capacity at present, it has already left behind Adani Power’s 648 MW solar power plant at Kamuthi, Tamil Nadu, India and 550 MW Topaz Solar Farm in California, USA in terms of total production capacity.


3. The Kurnool Ultra Mega Solar Park is spread over 5,811 acres of land.


4. In terms of unit production, the Kurnool Plant is producing eight million units of energy per day. This is sufficient to fulfill 80% of the district’s requirement. The park will produce 2,600 million units of power per annum.


5. The total investment by the developers and the government for this giant solar power park exceeds ₹7,000 crore. The Government of India has granted Rs 200 crore for the project.


6. The park has been developed under the solar parks scheme of Ministry of New and Renewable Energy, Government of India. It is set up by Andhra Pradesh Solar Power Corporation, with 4 joint developers: (i) Greenko (500 MW), (ii) Soft Bank Energy (350 MW), (iii) Azure Power (100 MW) and (iv) Prayatna Developers (Adani group) (50 MW).


7. The Kurnool Ultra Mega Solar Park has 40,00,000 solar panels of 315 watts each. With the help of 2,000 circuit kilometres of cables they are connected to the nearby four 220/33 kV pooling stations of 250 MW each and a 400 / 220 kV grid substation.


8. The developers – Sun Edison (M/s GreenKo) Soft Bank Energy, Azure Power and Prayatna Developers – had quoted a tariff of Rs. 4.63 per unit (kWh) during the auction. After bundling, the tariff to DISCOMS will come down to Rs. 4 per unit.


Don’t Revoke US Paris Climate Deal- 5 Interesting remarks by Bear Grylls on Climate Change

Bear Grylls, a well-known survival expert and a host of TV shows on the same subject, has expressed his concerns related to climate change, policies around it, energy and related issues often.  He is a supporter of the brigade that says that climate change is real and we need to protect our planet from it. Have a look at the 5 Interesting remarks by Bear Grylls on Climate Change:

5 Interesting remarks by Bear Grylls on Climate Change

Bear Grylls requests President Donald Trump not to opt out of Paris Climate Deal in one of his tweets. Photo Courtsy

1. Whatever our views: start of a new era & change keeps us on our toes! (Ps @realDonaldTrump plse though don’t revoke US Paris climate deal!)- 9 Nov 2016

Click to know What President Donald Trump has been saying about Climate change


2. We must also fight against the cynicism that questions global warming and we must fight against a lethargy that says it is too late or that isn’t our problem. It is not someone else’s problem.


Bear Grylls on Climate Change

Bear Grylls with President Obama. Photo Courtsy

3. On Obama’s Climate Action Plan: What you’ve done with your climate change plan is the most significant thing any single human being has ever done to protect planet.


4. I want my children in the future to know that I didn’t stand back and observe, but rather I made steps, however small they were, to bring about change.


5. We’ve only got one planet and we’ve got to protect it and look after it.


Climate Change is a Hoax tweets Donald Trump

President of the Unites States of America and the most powerful climate change denier of the world Mr. Donald Trump has said repeatedly that climate change is a hoax, a stupid thing, a canard and a manipulation by scientists.

These 10 interesting tweets of Donald Trump on Global Warming show his opinion and stand on global warming and climate change which are believed to be the most challenging threats to the mankind by many.

1. The concept of global warming was created by and for the Chinese in order to make U.S. manufacturing non-competitive.  6 Nov 2012


2. Any and all weather events are used by the GLOBAL WARMING HOAXSTERS to justify higher taxes to save our planet! They don’t believe it $$$$! 27 Jan 2014


3. Snowing in Texas and Louisiana, record setting freezing temperatures throughout the country and beyond. Global warming is an expensive hoax!  28 Jan 2014


Mr. Donald Trump is the most powerful climate change denier at present

Mr. Donald Trump is the most powerful climate change denier at present Pic Courtesy

4. We should be focused on clean and beautiful air-not expensive and business closing GLOBAL WARMING-a total hoax!  28 Dec 2013


5. Wow, it’s snowing in Isreal and on the pyramids in Egypt. Are we still wasting billions on the global warming con? MAKE U.S. COMPETITIVE! 14 Dec 2013


6. Let’s continue to destroy the competitiveness of our factories & manufacturing so we can fight mythical global warming. China is so happy! 1 Nov 2012


6. Windmills are the greatest threat in the US to both bald and golden eagles. Media claims fictional ‘global warming’ is worse.  9 Sep 2014


8. Global warming is based on faulty science and manipulated data which is proven by the emails that were leaked. 2 Nov 2012



President Donald Trump Does not believe in climate change Photo Courtesy

9. Global warming has been proven to be a canard repeatedly over and over again. The left needs a dose of reality. 28 Mar 2012


10. Whether Global Warming or Climate change. The fact is We didn’t cause it. We cannot change it. 18 Feb 2014

Tweet Courtsey

Greenland Ice Sheets are Melting From Below According to New Studies by NASA

According to the new studies carried out by NASA’ Oceans Melting Greenland (OMG) campaign Greenland Ice Sheets are Melting From Below. 

The interesting knowledge about the Greenland’s ice structures and its melting is being generated by NASA’s Oceans Melting Greenland (OMG) campaign. It’s a five year long mission started in 2015.

Ocean Melting Greenland (OMG) Campaign to Enhance the Knowledge on Melting of Greenland Ice Sheets 

Greenland’s coastline is 27,000-miles long. The OMG campaign studies the glaciers and ocean along the coastline. The aim of the campaign is to know where and how fast the seawater is melting the glacial ice. 

Both boats and aeroplanes are being used for the OMG campaign. Through the coastal channels the warm salty water of the Atlantic ocean reaches inside and melts ice sheets. The campaign is trying to make high resolution maps of the Greenland’s coast and pathways to get the detailed picture.

NASA’s G3 research plane is being used in the campaign. With the help of the sensors it reveals the temperature and salinity of the ocean up to the depth of 3000 feet. With the help of the GLISTIN radar it reveals the thinning and retreat of the glaciers from the below. These observations will help in bringing accuracy in the sea level rise projections.

As per the information provided by NASA referring two recent research publications that used OMG data, an understanding is being developed on how glaciers and ocean currents are interacting along Greenland’s west coast.

The OMG campaign is also helping towards improvement on seafloor maps used to predict future melting and subsequent sea level rise.

Few very interesting observations have come out from this campaign. According to the observations the sea water that surrounds the Greenland consists of two layers. The topmost layer is around ~600 feet deep. This layer contains relatively fresh cold water coming from the arctic while the layer below is salty & around 3 to 4 degrees Celsius warmer than the top layer. It is also saltier than the upper layer.

This subsurface layer is formed by the oceanic water coming from the south. The top layer weighs way less than the saltwater layer and therefore the two layers don’t mix much. Together it appears as if there is a cold fresh water river flowing above the warm salty ocean.

There are many coastal glaciers in Greenland. The interaction between the glaciers and the circulating water decides the rate of the ice melt.

The data gathered from the OMG observations reveal that if the sea shore in front of the coastal glaciers is shallow glaciers interact only with the top frigid freshwater. This reduces the rate of ice melt. Contrary, if the seafloor in front of the glaciers is deep, the warm subsurface layers melt the glaciers relatively rapidly from below.

These are the initial findings. Once the refined sea floor maps become available lot many interesting happening will reveal themselves. 

Why the knowledge about the melting of the Greenland Ice Sheets is important?

Greenland is the world’s largest island. Thick ice sheets cover 80% of the area of Greenland. More precisely 1,710,000 square kilometers area of Greenland is ice sheet covered. In most of the places the ice sheet is as thick as 2 km while it is ~3 km thick in the thickest areas.

Total 90% of the ice present in the earth is present as ice sheet in Antarctica and Greenland. As an estimate, the fresh water present as ice sheets in Greenland is so much that if all of it gets melted, it would lead to the rise in the oceans by more than 20 feet. But the relief is that it is not going to happen soon.

But the scientists are unanimously of the opinion that if it continues to melt at the present rate, by the end of this century it will lead to the sea level rise by 6-8 feet. The possible causes of the increased rate of Greenland ice sheets melting are rise in the sea and land temperatures, changing weather patterns etc.

The predicted sea level rise will have impacts on lives and livelihoods of billions of people live in the low land areas. Hence the melting of Greenland ice sheets is a phenomenon the scientists are keen to know more and more about.

Amazing Facts about Mangalyaan – India’s First Space Mission to Mars

Mangalyaan is India’s First Space Mission to Mars. The literal meaning of Mangalyaan is Mars-craft. With the help of Mangalyaan, scientists are able to know more about the Mars and its atmosphere. The scientists across the world are trying to study mars through this information and imagery. Read below to know more about some of the most amazing facts about Mangalyaan :

Amazing Facts about Mangalyaan

1. Mangalyaan has also been India’s most challenging space mission so far. This is also called the Mars Orbiter Mission (MOM). In India it is the Indian Space Research Organization (ISRO) that works to send rockets and satellites in the space. ISRO created history by sending the Mangalyaan to the Mars in the very first attempt.

2. This was India’s first space craft that intended to cross the earth’s orbit and go beyond to the orbit of another planet. Such a long and tough journey requires a very strong rocket. It was the powerful Polar Satellite Launch Vehicle (PSLV) that took the Mangalyaan to the Mars. The rocket was entirely indigenously built by the Indian scientists.

3. Mangalyaan started its journey towards Mars on 5th November 2013 from the space Centre situated at Sriharikota (Andhra Pradesh). Sriharikota is a barrier island off the Bay of Bengal. When the rocket got off from Shriharikota, its weight was 1337 kg. The part of the fuel to this weight was more than half. As the space craft moves forward the weight of the fuel gets reduced.

4. The Mangalyaan completed its journey in 298 days. It was a step-wise journey. It entered into the Mars’ orbit on 24th September 2014. With this India became the first Asian country to achieve this. Before that only Russian, European and the space agencies of USA could do that.

5. While orbiting Mars, the Mangalyaan continuously keep an eye on the Mars. It sends the information regarding the planet Mars to us. There are five instruments installed in Mangalyaan for this purpose. In scientific terms these instruments are called payloads. The scientists get very good quality of images and other information sent by Mangalyaan through waves.

6. The instruments loaded in the Mangalyaan need electricity to function. The wide solar panels installed in the Mangalyaan generate electricity. They are able to generate approximately 840 watt of electricity per day.

interesting facts about Mangalyaan

Newly Introduced 2000 Rs. Currency Note has the Picture of Mangalyaan on it. The solar Panels are clearly visible in it.

7. The successful execution of the Mars Orbit Mission signifies the advancement of the country towards the development of the technologies required for designing, planning, management and operations of an interplanetary mission. The knowledge related to the Mars’ surface features, morphology, mineralogy and atmosphere would be very crucial to develop understanding about the planet.

8. One of the remarkable achievements of this mission has been its cost effectiveness. The total cost of the mission was approximately ₹450 Crore which is way less than the cost of other similar missions worldwide.

Short Note on Mangalyaan