Sand art and play
Sand art is the practice of modelling sand into an artistic form, such as a sand brushing, sand sculpture, sandpainting, or sand bottles. A sandcastle is a type of sand sculpture resembling a miniature building, the two basic building ingredients and water, are available in abundance on a sandy beach, so most sand play takes place there, or in a sandpit. Tidal beaches generally have sand that limits height and structure because of the shape of the sand grains, good sculpture sand is somewhat dirty, having silt and clay that helps lock the irregular-shaped sand grains together. Sand castles are typically made by children for fun, but there are sand-sculpture contests for adults that involve large, complex constructions. The largest sandcastle made in a contest was 18 feet tall, the owner, Ronald Malcnujio and his sculpture consisted of one ton of sand and 10 litres of water to sculpt. Sand grains will always stick together unless the sand is reasonably fine, while dry sand is loose, wet sand is adherent if the proper amounts of sand and water are used in the mixture.
The reason for this is that water forms little bridges between the grains of sand when it is due to the forces of surface tension. When the sand dries out or gets wet, the shape of a structure may change, the mixture of fine and coarse sand granules is very important to achieve good sand construction results. Research is thus necessary to find the most suitable sand to achieve an optimal and buckets are the main construction tools used in creating sand castles and sand sculptures, although some people use only their hands. A simple sand castle can be made by filling a bucket with damp sand, placing it upside-down on the beach, for larger constructions, water from the sea to mix with the sand can be brought to the building site with a bucket or other container. Sometimes other materials, such as pieces of wood and plastic are constructed to hold piles of sand in place, Sand sculpting as an art form has become very popular in recent years, especially in coastal beach areas. Hundreds of annual competitions are all over the world.
Techniques can be sophisticated, and record-breaking achievements have been noted in the Guinness World Records. Sometimes, contests are staged as advertising or promotional events, most Sand sculptors come from other disciplines but there are a few that earn their living solely from Sand related activities. A variant on the sandcastle is the castle, made by mixing the sand with water. Some refer to the technique as dribbling, when the slurry of sand and water lands on existing sand structures, the effect is Gaudi-esque. From 1989 until 2009, a World Championship in Sand Sculpture was held in Harrison Hot Springs in Harrison, British Columbia, the competition had solo and team categories. The World championship was held in ft Myers and other venues for a limited time
A spring is any natural situation where water flows from an aquifer to the Earths surface. It is a component of the hydrosphere, a spring may be the result of karst topography where surface water has infiltrated the Earths surface, becoming part of the area groundwater. The groundwater travels through a network of cracks and fissure—openings ranging from intergranular spaces to large caves, the water eventually emerges from below the surface, in the form of a karst spring. The forcing of the spring to the surface can be the result of an aquifer in which the recharge area of the spring water table rests at a higher elevation than that of the outlet. Spring water forced to the surface by elevated sources are artesian wells and this is possible even if the outlet is in the form of a 300-foot-deep cave. In this case the cave is used like a hose by the higher elevated area of groundwater to exit through the lower elevation opening. Non-artesian springs may simply flow from a higher elevation through the earth to a lower elevation, still other springs are the result of pressure from an underground source in the earth, in the form of volcanic activity.
The result can be water at elevated temperature such as a hot spring, the action of the groundwater continually dissolves permeable bedrock such as limestone and dolomite, creating vast cave systems. The term seep refers to springs with small flow rates in which the water has filtered through permeable earth. Fracture springs, discharge from faults, joints, or fissures in the earth, tubular springs, in which the water flows from underground caverns. Spring discharge, or resurgence, is determined by the springs recharge basin, factors that affect the recharge include the size of the area in which groundwater is captured, the amount of precipitation, the size of capture points, and the size of the spring outlet. Water may leak into the system from many sources including permeable earth, sinkholes. In some cases entire creeks seemingly disappear as the water sinks into the ground via the stream bed, grand Gulf State Park in Missouri is an example of an entire creek vanishing into the groundwater system.
The water emerges 9 miles away, forming some of the discharge of Mammoth Spring in Arkansas, human activity may affect a springs discharge--withdrawal of groundwater reduces the water pressure in an aquifer, decreasing the volume of flow. Springs are often classified by the volume of the water they discharge, the largest springs are called first-magnitude, defined as springs that discharge water at a rate of at least 2800 liters or 100 cubic feet of water per second. The scale for spring flow is as follows, Minerals become dissolved in the water as it moves through the underground rocks and this may give the water flavor and even carbon dioxide bubbles, depending on the nature of the geology through which it passes. This is why spring water is bottled and sold as mineral water. Springs that contain significant amounts of minerals are sometimes called mineral springs, Springs that contain large amounts of dissolved sodium salts, mostly sodium carbonate, are called soda springs
Rajasthan is Indias largest state by area. Elsewhere it is bordered by the other Indian states, Punjab to the north and Uttar Pradesh to the northeast, Madhya Pradesh to the southeast, and Gujarat to the southwest. Rajasthan is home to two national reserves, the Ranthambore National Park in Sawai Madhopur and Sariska Tiger Reserve in Alwar. The state was formed on 30 March 1949 when Rajputana – the name adopted by the British Raj for its dependencies in the region – was merged into the Dominion of India. Its capital and largest city is Jaipur, known as Pink City, other important cities are Jodhpur, Bikaner and Ajmer. Parts of what is now Rajasthan were partly part of the Vedic Civilisation, kalibangan, in Hanumangarh district, was a major provincial capital of the Indus Valley Civilization. Matsya Kingdom of the Vedic civilisation of India, is said to roughly corresponded to the state of Jaipur in Rajasthan. The capital of Matsya was at Viratanagar, which is said to have named after its founder king Virata.
Bhargava identifies the two districts of Jhunjhunu and Sikar and parts of Jaipur district along with Haryana districts of Mahendragarh, bhargava locates the present day Sahibi River as the Vedic Drishadwati River, which along with Saraswati River formed the borders of the Vedic state of Brahmavarta. Manu and Bhrigu narrated the Manusmriti to a congregation of seers in this area only, the Indo-Scythians invaded the area of Ujjain and established the Saka era, marking the beginning of the long-lived Saka Western Satraps state. Gurjars ruled for many dynasties in this part of the country, up to the tenth century almost the whole of North India, acknowledged the supremacy of the Gurjars with their seat of power at Kannauj. The Gurjar Pratihar Empire acted as a barrier for Arab invaders from the 8th to the 11th century, the chief accomplishment of the Gurjara Pratihara empire lies in its successful resistance to foreign invasions from the west, starting in the days of Junaid. Majumdar says that this was acknowledged by the Arab writers.
He further notes that historians of India have wondered at the progress of Muslim invaders in India. Traditionally the Rajputs, Meenas, REBARI, Bhils, Charans, Bishnois, PhulMali, all these tribes suffered great difficulties in protecting their culture and the land. Millions of them were killed trying to protect their land, a number of Gurjars had been exterminated in Bhinmal and Ajmer areas fighting with the invaders. Meenas were rulers of Bundi and the Dhundhar region, hem Chandra Vikramaditya, the Hindu Emperor, was born in the village of Machheri in Alwar District in 1501. Hem Chandra was killed in the battlefield at Second Battle of Panipat fighting against Mughals on 5 November 1556, maharana Pratap of Mewar resisted Akbar in the famous Battle of Haldighati and operated from hilly areas of his kingdom
A brand is a name, design, symbol, or other feature that distinguishes one seller’s product from those of others. Brands are used in business and advertising, the term has been extended to mean a strategic personality for a product or company, so that ‘brand’ now suggests the values and promises that a consumer may perceive and buy into. Branding is a set of marketing and communication methods that help to distinguish a company from competitors, the key components that form a brands toolbox include a brand’s identity, brand communication, brand awareness, brand loyalty, and various branding strategies. Brand equity is the totality of a brands worth and is validated by assessing the effectiveness of these branding components. To reach such an invaluable brand prestige requires a commitment to a way of doing business. A corporation who exhibits a strong brand culture is dedicated on producing intangible outputs such as customer satisfaction, reduced price sensitivity and customer loyalty. A brand is in essence a promise to its customers that they can expect long-term security, when a customer is familiar with a brand or favours it incomparably to its competitors, this is when a corporation has reached a high level of brand equity.
Many companies are beginning to understand there is often little to differentiate between products in the 21st century. Branding remains the last bastion for differentiation, in accounting, a brand defined as an intangible asset is often the most valuable asset on a corporation’s balance sheet. The word ‘brand’ is often used as a referring to the company that is strongly identified with a brand. Marque or make are often used to denote a brand of motor vehicle, a concept brand is a brand that is associated with an abstract concept, like breast cancer awareness or environmentalism, rather than a specific product, service, or business. A commodity brand is a associated with a commodity. The word, derives from Dutch brand meaning to burn and this product was developed at Dhosi Hill, an extinct volcano in northern India. Roman glassmakers branded their works, with Ennion being the most prominent, the Italians used brands in the form of watermarks on paper in the 13th century. Blind Stamps and silver-makers marks are all types of brand, industrialization moved the production of many household items, such as soap, from local communities to centralized factories.
When shipping their items, the factories would literally brand their logo or insignia on the barrels used, Bass & Company, the British brewery, claims their red-triangle brand as the worlds first trademark. Another example comes from Antiche Fornaci Giorgi in Italy, which has stamped or carved its bricks with the same proto-logo since 1731, cattle-branding has been used since Ancient Egypt. The term, originally meaning an un-branded calf, came from a Texas pioneer rancher, Sam Maverick, use of the word maverick spread among cowboys and came to apply to unbranded calves found wandering alone
Death Valley is a desert valley located in Eastern California. It is one of the hottest places in the world at the height of summertime along with deserts in Africa, Death Valleys Badwater Basin is the point of the lowest elevation in North America, at 282 feet below sea level. This point is 84.6 miles east-southeast of Mount Whitney, Death Valleys Furnace Creek holds the record for the highest reliably recorded air temperature in the world,134 °F on July 10,1913. This has been contested by other weather experts and it is located mostly in Inyo County, California. It has an area of about 3,000 sq mi, the highest point in Death Valley itself is Telescope Peak in the Panamint Range, which has an elevation of 11,043 feet. Death Valley is one of the best geological examples of a basin and it lies at the southern end of a geological trough known as Walker Lane, which runs north into Oregon. The valley is bisected by a right lateral slip fault system, represented by the Death Valley Fault. The eastern end of the left lateral Garlock Fault intersects the Death Valley Fault, Furnace Creek and the Amargosa River flow through the valley but eventually disappear into the sands of the valley floor.
Death Valley contains salt pans, according to current geological consensus, at various times during the middle of the Pleistocene era, inland lakes formed in Death Valley. Lake Manly received water overflowing from a chain of other Pleistocene lakes, Death Valley has a subtropical, hot desert climate, with long, extremely hot summers and short, warm or mild winters, as well as little rainfall. As a general rule, lower altitudes tend to have higher temperatures, when the sun heats the ground, that heat is radiated upward, but the dense below-sea-level air absorbs some of this radiation and radiates some of it back towards the ground. In addition, the valley walls trap rising hot air and recycle it back down to the valley floor. This process is important in Death Valley, as it provides its specific climate. The valley is surrounded by mountains, while its surface is flat and devoid of plants, so much of the suns heat can reach the ground, absorbed by soil. When air at ground level is heated, it begins to rise, moving up past steep, high mountain ranges, which cools slightly, sinking back down towards the valley more compressed.
This air is reheated by the sun to a higher temperature, moving up the mountain again, whereby the air moves up and down in a circular motion in cycles. This heated air increases ground temperature markedly, forming the hot wind currents that are trapped by atmospheric pressure and mountains, Death Valley holds temperature records because it has an unusually high number of factors that lead to high atmospheric temperatures. The depth and shape of Death Valley influence its summer temperatures, the valley is a long, narrow basin 282 feet below sea level, yet is walled by high, steep mountain ranges
Yosemite National Park
Yosemite National Park is a national park spanning portions of Tuolumne and Madera counties in Northern California. The park, which is managed by the National Park Service, on average, about 4 million people visit Yosemite each year, and most spend the majority of their time in the seven square miles of Yosemite Valley. The park set a record in 2016, surpassing 5 million visitors for the first time in its history. Almost 95% of the park is designated wilderness, Yosemite was central to the development of the national park idea. First, Galen Clark and others lobbied to protect Yosemite Valley from development, Yosemite is one of the largest and least fragmented habitat blocks in the Sierra Nevada, and the park supports a diversity of plants and animals. The park has a range from 2,127 to 13,114 feet and contains five major vegetation zones, chaparral/oak woodland, lower montane forest, upper montane forest, subalpine zone. Of Californias 7,000 plant species, about 50% occur in the Sierra Nevada, there is suitable habitat for more than 160 rare plants in the park, with rare local geologic formations and unique soils characterizing the restricted ranges many of these plants occupy.
The geology of the Yosemite area is characterized by granitic rocks, about 10 million years ago, the Sierra Nevada was uplifted and tilted to form its relatively gentle western slopes and the more dramatic eastern slopes. The uplift increased the steepness of stream and river beds, resulting in formation of deep, about one million years ago and ice accumulated, forming glaciers at the higher alpine meadows that moved down the river valleys. Ice thickness in Yosemite Valley may have reached 4,000 feet during the early glacial episode, the downslope movement of the ice masses cut and sculpted the U-shaped valley that attracts so many visitors to its scenic vistas today. The name Yosemite originally referred to the name of a tribe which was driven out of the area by the Mariposa Battalion. Before the area was called Ahwahnee by indigenous people, as revealed by archeological finds, the Yosemite Valley has been inhabited for nearly 3,000 years, though humans may have first visited the area as long as 8,000 to 10,000 years ago.
The indigenous natives called themselves the Ahwahneechee, meaning dwellers in Ahwahnee and they are related to the Northern Paiute and Mono tribes. Many tribes visited the area to trade, including nearby Central Sierra Miwoks, a major trading route went over Mono Pass and through Bloody Canyon to Mono Lake, just to the east of the Yosemite area. Vegetation and game in the region were similar to that present today, acorns were a staple to their diet, as well as seeds and plants, salmon. In 1851 as part of the Mariposa Wars intended to suppress Native American resistance and he was pursuing forces of around 200 Ahwahneechee led by Chief Tenaya. Accounts from this battalion were the first well-documented reports of ethnic Europeans entering Yosemite Valley, attached to Savages unit was Dr. Lafayette Bunnell, the company physician, who wrote about his awestruck impressions of the valley in The Discovery of the Yosemite. Bunnell is credited with naming Yosemite Valley, based on his interviews with Chief Tenaya, Bunnell wrote that Chief Tenaya was the founder of the Pai-Ute Colony of Ah-wah-nee
Mayflies are aquatic insects belonging to the order Ephemeroptera. This order is part of an ancient group of insects termed the Palaeoptera, over 3,000 species of mayfly are known worldwide, grouped into over 400 genera in 42 families. Their immature stages are aquatic fresh water forms, whose presence indicates a clean and they are unique among insect orders in having a fully winged terrestrial adult stage, the subimago, which moults into a sexually mature adult, the imago. Mayflies hatch from spring to autumn, not necessarily in May, fly fishermen make use of mayfly hatches by choosing artificial fishing flies that resemble the species in question. One of the most famous English mayflies is Rhithrogena germanica, the fishermans March brown mayfly, the brief lives of mayfly adults have been noted by naturalists and encyclopaedists since Aristotle and Pliny the Elder in classical times. The German engraver Albrecht Dürer included a mayfly in his 1495 engraving The Holy Family with the Mayfly to suggest a link between heaven and earth.
The English poet George Crabbe compared the life of a daily newspaper with that of a mayfly in the satirical poem The Newspaper. Immature mayflies are aquatic, and are known as nymphs or naiads, in contrast to their short lives as adults, they may live for several years in the water. They have an elongated, cylindrical or somewhat flattened body that passes through a number of instars, when ready to emerge from the water, nymphs vary in length, depending on species, from 3 to 30 mm. The head has an outer covering of sclerotin, often with various hard ridges and projections, it points either forwards or downwards. There are two large eyes, three ocelli and a pair of antennae of variable lengths, set between or in front of the eyes. The mouthparts are designed for chewing and consist of a labrum, a pair of strong mandibles, a pair of maxillae, a membranous hypopharynx. The thorax consists of three segments – the hindmost two, the mesothorax and metathorax, being fused, each segment bears a pair of legs which usually terminate in a single claw.
The legs are robust and often clad in bristles, hairs or spines, wing pads develop on the mesothorax, and in some species, hindwing pads develop on the metathorax. The abdomen consists of ten segments, some of which may be obscured by a pair of operculate gills. The abdomen terminates in a pair of, or three, slender thread-like projections. The final moult of the nymph is not to the adult form, but to a winged stage called a subimago that physically resembles the adult. The subimago often has partially cloudy wings fringed with hairs, its eyes, legs
In hydrology, snowmelt is surface runoff produced from melting snow. It can be used to describe the period or season during which such runoff is produced, water produced by snowmelt is an important part of the annual water cycle in many parts of the world, in some cases contributing high fractions of the annual runoff in a watershed. Predicting snowmelt runoff from a basin may be a part of designing water control projects. If the snowmelt is frozen, very dangerous conditions and accidents can occur, there are several energy fluxes involved in the melting of snow. These fluxes can act in opposing directions, that is either delivering heat to or removing heat from the snowpack, ground heat flux is the energy delivered to the snowpack from the soil below by conduction. Radiation inputs to the snowpack include net shortwave and longwave radiation, net shortwave radiation is the difference in energy received from the sun and that reflected by the snowpack because of the snowpack albedo. Longwave radiation is received by the snowpack from many sources, including ozone, carbon dioxide, longwave radiation is emitted by the snowpack in the form near-Black-body radiation, where snow has an emissivity between 0.97 and 1.0.
Generally the net longwave radiation term is negative, meaning a net loss of energy from the snowpack, latent heat flux is the energy removed from or delivered to the snowpack which accompanies the mass transfers of evaporation, sublimation, or condensation. Sensible heat flux is the flux due to convection between the air and snowpack. In northern Alaska, the melt-date has advanced by 8 days since the mid-1960s, decreased snowfall in winter followed by warmer spring conditions seems to be the cause for the advance. In Europe, the recent heat wave has especially been anomalous at higher altitudes, for the first time on record, some of the highest Alpine peaks in Europe are snow-free. Although it would seem that the two are related, the question of how much of this is due to climate change firmly remains a center of debate, increased water runoff due to snowmelt was a cause of many famous floods. One well-known example is the Red River Flood of 1997, when the Red River of the North in the Red River Valley of the United States and Canada flooded.
Flooding in the Red River Valley is augmented by the fact that the river north through Winnipeg, Manitoba. As snow in Minnesota, North Dakota, and South Dakota begins to melt and flow into the Red River, colder temperatures downstream can potentially lead to freezing of water as it flows north, thus augmenting the ice dam problem. Some areas in British Columbia are prone to flooding as well. The date of annual melt is of great interest as an indicator of climate change. Large year-to-year variability complicates the picture and furthers the debate, inter-annual variability of springtime snow pack comes largely from variability of winter month precipitation which is in turn related to the variability of key patterns of atmospheric circulation
India, officially the Republic of India, is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and it is bounded by the Indian Ocean on the south, the Arabian Sea on the southwest, and the Bay of Bengal on the southeast. It shares land borders with Pakistan to the west, China and Bhutan to the northeast, in the Indian Ocean, India is in the vicinity of Sri Lanka and the Maldives. Indias Andaman and Nicobar Islands share a border with Thailand. The Indian subcontinent was home to the urban Indus Valley Civilisation of the 3rd millennium BCE, in the following millennium, the oldest scriptures associated with Hinduism began to be composed. Social stratification, based on caste, emerged in the first millennium BCE, early political consolidations took place under the Maurya and Gupta empires, the peninsular Middle Kingdoms influenced cultures as far as southeast Asia. In the medieval era, Zoroastrianism and Islam arrived, much of the north fell to the Delhi sultanate, the south was united under the Vijayanagara Empire.
The economy expanded in the 17th century in the Mughal empire, in the mid-18th century, the subcontinent came under British East India Company rule, and in the mid-19th under British crown rule. A nationalist movement emerged in the late 19th century, which later, under Mahatma Gandhi, was noted for nonviolent resistance, in 2015, the Indian economy was the worlds seventh largest by nominal GDP and third largest by purchasing power parity. Following market-based economic reforms in 1991, India became one of the major economies and is considered a newly industrialised country. However, it continues to face the challenges of poverty, malnutrition, a nuclear weapons state and regional power, it has the third largest standing army in the world and ranks sixth in military expenditure among nations. India is a constitutional republic governed under a parliamentary system. It is a pluralistic and multi-ethnic society and is home to a diversity of wildlife in a variety of protected habitats. The name India is derived from Indus, which originates from the Old Persian word Hindu, the latter term stems from the Sanskrit word Sindhu, which was the historical local appellation for the Indus River.
The ancient Greeks referred to the Indians as Indoi, which translates as The people of the Indus, the geographical term Bharat, which is recognised by the Constitution of India as an official name for the country, is used by many Indian languages in its variations. Scholars believe it to be named after the Vedic tribe of Bharatas in the second millennium B. C. E and it is traditionally associated with the rule of the legendary emperor Bharata. Gaṇarājya is the Sanskrit/Hindi term for republic dating back to the ancient times, hindustan is a Persian name for India dating back to the 3rd century B. C. E. It was introduced into India by the Mughals and widely used since and its meaning varied, referring to a region that encompassed northern India and Pakistan or India in its entirety
Arabidopsis thaliana is a small flowering plant native to Eurasia. A. thaliana is considered a weed, it is found by roadsides, a winter annual with a relatively short life cycle, A. thaliana is a popular model organism in plant biology and genetics. For a complex multicellular eukaryote, A. thaliana has a small genome of approximately 135 megabase pairs. It was the first plant to have its genome sequenced, and is a tool for understanding the molecular biology of many plant traits, including flower development. Arabidopsis thaliana is a plant, usually growing to 20–25 cm tall. The leaves form a rosette at the base of the plant, leaves are covered with small, unicellular hairs. The flowers are 3 mm in diameter, arranged in a corymb, the fruit is a siliqua 5–20 mm long, containing 20–30 seeds. Roots are simple in structure, with a primary root that grows vertically downward. These roots form interactions with rhizosphere bacteria such as Bacillus megaterium, a. thaliana can complete its entire lifecycle in six weeks.
The central stem produces flowers grows after about three weeks, and the flowers naturally self-pollinate. In the lab, A. thaliana may be grown in Petri plates, pots, or hydroponics, the plant was first described in 1577 in the Harz Mountains by Johannes Thal, a physician from Nordhausen, Thüringen, who called it Pilosella siliquosa. In 1753, Carl Linnaeus renamed the plant Arabis thaliana in honor of Thal, in 1842, the German botanist Gustav Heynhold erected the new genus Arabidopsis and placed the plant in that genus. The genus name, comes from Greek, meaning resembling Arabis, thousands of natural inbred accessions of A. thaliana have been collected from throughout its natural and introduced range. These accessions exhibit considerable genetic and phenotypic variation which can be used to study the adaptation of species to different environments. A. thaliana is native to Europe and northwestern Africa and it appears to be native in tropical afroalpine ecosystems. It has been introduced and naturalized worldwide, a. thaliana readily grows and often pioneers rocky and calcareous soils.
It is generally considered a weed, due to its distribution in agricultural fields, railway lines, waste ground. Like most Brassicaceae species, A. thaliana is edible by humans as a salad or cooked, the first mutant in A. thaliana was documented in 1873 by Alexander Braun, describing a double flower phenotype
Artemia is a genus of aquatic crustaceans known as brine shrimp, Aqua Dragons, or Sea Monkeys. Artemia, the genus in the family Artemiidae, has changed little externally since the Triassic period. Artemia populations are found worldwide in inland lakes, but not in oceans. Artemia are able to avoid cohabiting with most types of predators, such as fish, the ability of the Artemia to produce dormant eggs, known as cysts, has led to extensive use of Artemia in aquaculture. The cysts may be stored for long periods and hatched on demand to provide a convenient form of feed for larval fish. Nauplii of the brine shrimp Artemia constitute the most widely used food item, in addition, the resilience of Artemia makes them ideal animals for running biological toxicity assays and it has become a model organism used to test the toxicity of chemicals. Breeds of Artemia are sold as novelty gifts under the marketing name Sea-Monkeys or Aqua Dragons, the brine shrimp Artemia comprises a group of seven to nine species very likely to have diverged from an ancestral form living in the Mediterranean area about 5.5 million years ago.
Artemia is a typical primitive arthropod with a body to which is attached broad leaf-like appendages. The total length is usually about 8–10 millimetres for the male and 10–12 mm for the female. The body of Artemia is divided into head, the entire body is covered with a thin, flexible exoskeleton of chitin to which muscles are attached internally and shed periodically. In female Artemia a moult precedes every ovulation, the voluntary shedding or dropping of parts of the body for defence, is controlled locally along the nervous system. Artemia have two types of eyes and they have two widely separated compound eyes mounted on flexible stalks. These compound eyes are the main sense organ in adult brine shrimps. The median eye, or the eye, is situated anteriorly in the centre of the head and is the only functional optical sense organ in the nauplii. Brine shrimp can tolerate any levels of salinity from 25‰ to 250‰, with a range of 60‰–100‰. Physiologically, optimal levels of salinity are about 30–35‰, but due to predators at these salt levels, locomotion is achieved by the rhythmic beating of the appendages acting in pairs.
Adult female brine shrimp ovulate approximately every 140 hours, in favourable conditions, the female brine shrimp can produce eggs that almost immediately hatch. While in extreme conditions, such as low level or salinity above 150‰
Niger, officially the Republic of Niger, is a landlocked country in Western Africa, named after the Niger River. Niger is bordered by Libya to the northeast, Chad to the east and Benin to the south, Burkina Faso and Mali to the west, and Algeria to the northwest. Niger covers a area of almost 1,270,000 km2, making it the largest country in West Africa. The countrys predominantly Islamic population of about 19 million is mostly clustered in the far south, the capital city is Niamey, located in the far-southwest corner of Niger. Niger is a country, and is consistently one of the lowest-ranked in the United Nations Human Development Index. Much of the portions of the country are threatened by periodic drought. The economy is concentrated around subsistence and some export agriculture clustered in the fertile south. Nigerien society reflects a diversity drawn from the long independent histories of its ethnic groups and regions. Historically, what is now Niger has been on the fringes of large states.
Since independence, Nigeriens have lived under five constitutions and three periods of military rule, following a military coup in 2010, Niger has become a democratic, multi-party state. A majority live in areas, and have little access to advanced education. Early human settlement in Niger is evidenced by archaeological remains. In prehistoric times, the climate of the Sahara was wet and provided favorable conditions for agriculture, in 2005–06, a graveyard in the Tenere desert was discovered by Paul Sereno, a paleontologist from the University of Chicago. His team discovered 5, 000-year-old remains of a woman and two children in the Tenere Desert, the evidence along with remains of animals that do not typically live in desert are among the strongest evidence of the green Sahara in Niger. It is believed that progressive desertification around 5000 BCE pushed sedentary populations to the south and south-east. By at least the 5th century BCE, Niger became an area of trade, led by the Berber tribes from the north.
This trade has made Agadez a pivotal place of the trans-Saharan trade and this mobility, which would continue in waves for several centuries, was accompanied with further migration to the south and interbreeding between southern black and northern white populations. It was aided by the introduction of Islam to the region at the end of the 7th century, several empires and kingdoms flourished during this era up to the beginning of colonization in Africa