Sumatra is a large island in western Indonesia, part of the Sunda Islands. It is the largest island, located in Indonesia and the sixth-largest island in the world at 473,481 km2. Sumatra is an elongated landmass spanning a diagonal northwest-southeast axis; the Indian Ocean borders the west and southwest coasts of Sumatra with the island chain of Simeulue and Mentawai off the western coast. In the northeast the narrow Strait of Malacca separates the island from the Malay Peninsula, an extension of the Eurasian continent. In the southeast the narrow Sunda Strait separates Sumatra from Java; the northern tip of Sumatra borders the Andaman Islands, while off the southeastern coast lie the islands of Bangka and Belitung, Karimata Strait and the Java Sea. The Bukit Barisan mountains, which contain several active volcanoes, form the backbone of the island, while the northeastern area contains large plains and lowlands with swamps, mangrove forest and complex river systems; the equator crosses the island at its center in West Riau provinces.
The climate of the island is tropical and humid. Lush tropical rain forest once dominated the landscape. Sumatra has a wide range of plant and animal species but has lost 50% of its tropical rainforest in the last 35 years. Many species are now critically endangered, such as the Sumatran ground cuckoo, the Sumatran tiger, the Sumatran elephant, the Sumatran rhinoceros, the Sumatran orangutan. Deforestation on the island has resulted in serious seasonal smoke haze over neighbouring countries, such as the 2013 Southeast Asian haze causing considerable tensions between Indonesia and affected countries Malaysia and Singapore. Sumatra was known in ancient times by the Sanskrit names of Swarnadwīpa and Swarnabhūmi, because of the gold deposits in the island's highlands; the first mention of the name of Sumatra was in the name of Srivijayan Haji Sumatrabhumi, who sent an envoy to China in 1017. Arab geographers referred to the island as Lamri in the tenth through thirteenth centuries, in reference to a kingdom near modern-day Banda Aceh, the first landfall for traders.
The island is known by other names namely, Andalas or Percha Island. Late in the 14th century the name Sumatra became popular in reference to the kingdom of Samudra Pasai, a rising power until replaced by the Sultanate of Aceh. Sultan Alauddin Shah of Aceh, in letters addressed to Queen Elizabeth I of England in 1602, referred to himself as "king of Aceh and Samudra"; the word itself is from Sanskrit "Samudra", meaning "gathering together of waters, sea or ocean". Marco Polo named the kingdom Samara or Samarcha in the late 13th century, while the 14th century traveller Odoric of Pordenone used Sumoltra for Samudra. Subsequent European writers used similar forms of the name for the entire island. European writers in the 19th century found that the indigenous inhabitants did not have a name for the island; the Melayu Kingdom was absorbed by Srivijaya. Srivijayan influence waned in the 11th century after it was defeated by the Chola Empire of southern India. At the same time, Islam made its way to Sumatra through Arabs and Indian traders in the 6th and 7th centuries AD.
By the late 13th century, the monarch of the Samudra kingdom had converted to Islam. Marco Polo visited the island in 1292. Ibn Battuta visited with the sultan for 15 days, noting the city of Samudra was "a fine, big city with wooden walls and towers," and another 2 months on his return journey. Samudra was succeeded by the powerful Aceh Sultanate. With the coming of the Dutch, the many Sumatran princely states fell under their control. Aceh, in the north, was the major obstacle, as the Dutch were involved in the long and costly Aceh War; the Free Aceh Movement fought against Indonesian government forces in the Aceh Insurgency from 1976 to 2005. Security crackdowns in 2001 and 2002 resulted in several thousand civilian deaths; the longest axis of the island runs 1,790 km northwest–southeast, crossing the equator near the centre. At its widest point, the island spans 435 km; the interior of the island is dominated by two geographical regions: the Barisan Mountains in the west and swampy plains in the east.
Sumatra is the closest Indonesian island to mainland Asia. To the southeast is Java, separated by the Sunda Strait. To the north is the Malay Peninsula, separated by the Strait of Malacca. To the east is Borneo, across the Karimata Strait. West of the island is the Indian Ocean; the Great Sumatran fault, the Sunda megathrust, run the entire length of the island along its west coast. On 26 December 2004, the western coast and islands of Sumatra Aceh province, were struck by a tsunami following the Indian Ocean earthquake; this was the longest earthquake recorded, lasting between 600 seconds. More than 170,000 Indonesians were killed in Aceh. Other recent earthquakes to strike Sumatra include the 2005 Nias–Simeulue earthquake and the 2010 Mentawai earthquake and tsunami. To the east, big rivers carry silt from the mountains, forming the vast lowland interspersed by swamps. If unsuitable for farming, the area is of great economic importance for Indonesia, it produces oil from both above and below the soil -- petroleum.
Sumatra is the largest producer of Indonesian coffee. Small-holders grow Arabica coffee in the highlands, while Rob
Hauts-de-France, is a region of France created by the territorial reform of French Regions in 2014, from a merger of Nord-Pas-de-Calais and Picardy. Its capital is Lille; the new region came into existence on 1 January 2016, after the regional elections in December 2015. France's Conseil d'État approved Hauts-de-France as the name of the region on 28 September 2016, effective 30 September 2016. With 6,009,976 inhabitants, a population of 189 inhabitants/km2, it represents the 3rd most populous region in France and the 2nd most densely populated in metropolitan France after Île-de-France; the region covers an area of more than 31,813 km2. It borders Normandy, Grand Est, Île-de-France and the United Kingdom via the English Channel; the region's interim name Nord-Pas-de-Calais-Picardie was a hyphenated placename, created by hyphenating the merged regions' names—Nord-Pas-de-Calais and Picardie—in alphabetical order. On 14 March 2016, well ahead of the 1 July deadline, the Regional council decided on Hauts-de-France as the region's permanent name.
The provisional name of the region was retired on 30 September 2016, when the new name of the region, Hauts-de-France, took effect. The region borders Belgium to the northeast, the English Channel to the northwest, as well as the French regions of Grand Est to the southeast, Île-de-France to the south, Normandy to the southwest, it is connected to the United Kingdom via the Channel Tunnel. Hauts-de-France comprises five departments: Aisne, Oise, Pas-de-Calais, Somme. Lille Amiens Roubaix Tourcoing Dunkirk Calais Villeneuve-d'Ascq Saint-Quentin Beauvais Valenciennes The region was a pivotal center of mulquinerie Nord-Pas-de-Calais Picardy Regions of France Canadian National Vimy Memorial Battle of Vimy Ridge Regional Council of the Hauts-de-France Official website Merger of the regions - France 3
Population genetics is a subfield of genetics that deals with genetic differences within and between populations, is a part of evolutionary biology. Studies in this branch of biology examine such phenomena as adaptation and population structure. Population genetics was a vital ingredient in the emergence of the modern evolutionary synthesis, its primary founders were Sewall Wright, J. B. S. Haldane and Ronald Fisher, who laid the foundations for the related discipline of quantitative genetics. Traditionally a mathematical discipline, modern population genetics encompasses theoretical and field work. Population genetic models are used both for statistical inference from DNA sequence data and for proof/disproof of concept. What sets population genetics apart today from newer, more phenotypic approaches to modelling evolution, such as evolutionary game theory and adaptive dynamics, is its emphasis on genetic phenomena as dominance and the degree to which genetic recombination breaks up linkage disequilibrium.
This makes it appropriate for comparison to population genomics data. Population genetics began as a reconciliation of Mendelian biostatistics models. Natural selection will only cause evolution. Before the discovery of Mendelian genetics, one common hypothesis was blending inheritance, but with blending inheritance, genetic variance would be lost, making evolution by natural or sexual selection implausible. The Hardy–Weinberg principle provides the solution to how variation is maintained in a population with Mendelian inheritance. According to this principle, the frequencies of alleles will remain constant in the absence of selection, mutation and genetic drift; the next key step was the work of statistician Ronald Fisher. In a series of papers starting in 1918 and culminating in his 1930 book The Genetical Theory of Natural Selection, Fisher showed that the continuous variation measured by the biometricians could be produced by the combined action of many discrete genes, that natural selection could change allele frequencies in a population, resulting in evolution.
In a series of papers beginning in 1924, another British geneticist, J. B. S. Haldane, worked out the mathematics of allele frequency change at a single gene locus under a broad range of conditions. Haldane applied statistical analysis to real-world examples of natural selection, such as peppered moth evolution and industrial melanism, showed that selection coefficients could be larger than Fisher assumed, leading to more rapid adaptive evolution as a camouflage strategy following increased pollution; the American biologist Sewall Wright, who had a background in animal breeding experiments, focused on combinations of interacting genes, the effects of inbreeding on small isolated populations that exhibited genetic drift. In 1932 Wright introduced the concept of an adaptive landscape and argued that genetic drift and inbreeding could drive a small, isolated sub-population away from an adaptive peak, allowing natural selection to drive it towards different adaptive peaks; the work of Fisher and Wright founded the discipline of population genetics.
This integrated natural selection with Mendelian genetics, the critical first step in developing a unified theory of how evolution worked. John Maynard Smith was Haldane's pupil, whilst W. D. Hamilton was influenced by the writings of Fisher; the American George R. Price worked with both Maynard Smith. American Richard Lewontin and Japanese Motoo Kimura were influenced by Wright; the mathematics of population genetics were developed as the beginning of the modern synthesis. Authors such as Beatty have asserted that population genetics defines the core of the modern synthesis. For the first few decades of the 20th century, most field naturalists continued to believe that Lamarckism and orthogenesis provided the best explanation for the complexity they observed in the living world. During the modern synthesis, these ideas were purged, only evolutionary causes that could be expressed in the mathematical framework of population genetics were retained. Consensus was reached as to which evolutionary factors might influence evolution, but not as to the relative importance of the various factors.
Theodosius Dobzhansky, a postdoctoral worker in T. H. Morgan's lab, had been influenced by the work on genetic diversity by Russian geneticists such as Sergei Chetverikov, he helped to bridge the divide between the foundations of microevolution developed by the population geneticists and the patterns of macroevolution observed by field biologists, with his 1937 book Genetics and the Origin of Species. Dobzhansky examined the genetic diversity of wild populations and showed that, contrary to the assumptions of the population geneticists, these populations had large amounts of genetic diversity, with marked differences between sub-populations; the book took the mathematical work of the population geneticists and put it into a more accessible form. Many more biologists were influenced by population genetics via Dobzhansky than were able to read the mathematical works in the original. In Great Britain E. B. Ford, the pioneer of ecological genetics, continued throughout the 1930s and 1940s to empirically demonstrate the power of selection due to ecological factors including the ability to maintain genetic diversity through genetic polymorphisms such as human blood types.
Ford's work, in collaboration with Fisher, contributed to a shift in emphasis during the course of the modern synthesis towards natural selection as the dominant force. The original, modern synthesis view of population genetics assumes that mutations provi
Reed beds are natural habitats found in floodplains, waterlogged depressions, estuaries. Reed beds are part of a succession from young reeds colonising open water or wet ground through a gradation of dry ground; as reed beds age, they build up a considerable litter layer that rises above the water level and that provides opportunities for scrub or woodland invasion. Artificial reed beds are used to remove pollutants from grey water. Reed beds vary in the species that they can support, depending upon water levels within the wetland system, seasonal variations, the nutrient status and salinity of the water. Reed swamps have 20 cm or more of surface water during the summer and have high invertebrate and bird species use. Reed fens have water levels at or below the surface during the summer and are more botanically complex. Reeds and similar plants do not grow in acidic water. Although common reeds are characteristic of reed beds, not all vegetation dominated by this species is characteristic of reed beds.
It commonly occurs in unmanaged, damp grassland and as an understorey in certain types of damp woodland. Most European reed beds comprise Phragmites australis but include many other tall monocotyledons adapted to growing in wet conditions – other grasses such as reed sweet-grass, Canary reed-grass and small-reed, large sedges, yellow flag iris, reed-mace, water-plantains, flowering rush. Many dicotyledons occur, such as water mint, skull-cap, touch-me-not balsam and water forget-me-nots. Many animals are adapted to living around reed-beds; these include mammals such as Eurasian otter, European beaver, water vole, Eurasian harvest mouse and water shrew, birds such as great bittern, purple heron, European spoonbill, water rail, purple gallinule, marsh harrier, various warblers, bearded reedling and reed bunting. Constructed wetlands are artificial swamps using reed or other marshland plants to form part of small-scale sewage treatment systems. Water trickling through the reed bed is cleaned by microorganisms living on the root system and in the litter.
These organisms utilize the sewage for growth nutrients. The process is similar to aerobic conventional sewage treatment, as the same organisms are used, except that conventional treatment systems require artificial aeration. Treatment ponds are small versions of constructed wetlands which uses reed beds or other marshland plants to form an smaller water treatment system. Similar to constructed wetlands, water trickling through the reed bed is cleaned by microorganisms living on the root system and in the litter. Treatment ponds are used for the water treatment of a small neighbourhood. Organisms used in water purification South Milton Ley
A wetland is a distinct ecosystem, inundated by water, either permanently or seasonally, where oxygen-free processes prevail. The primary factor that distinguishes wetlands from other land forms or water bodies is the characteristic vegetation of aquatic plants, adapted to the unique hydric soil. Wetlands play a number of functions, including water purification, water storage, processing of carbon and other nutrients, stabilization of shorelines, support of plants and animals. Wetlands are considered the most biologically diverse of all ecosystems, serving as home to a wide range of plant and animal life. Whether any individual wetland performs these functions, the degree to which it performs them, depends on characteristics of that wetland and the lands and waters near it. Methods for assessing these functions, wetland ecological health, general wetland condition have been developed in many regions and have contributed to wetland conservation by raising public awareness of the functions and the ecosystem services some wetlands provide.
Wetlands occur on every continent. The main wetland types are swamp, marsh and fen. Many peatlands are wetlands; the water in wetlands is either brackish, or saltwater. Wetlands can be non-tidal; the largest wetlands include the Amazon River basin, the West Siberian Plain, the Pantanal in South America, the Sundarbans in the Ganges-Brahmaputra delta. The UN Millennium Ecosystem Assessment determined that environmental degradation is more prominent within wetland systems than any other ecosystem on Earth. Constructed wetlands are used to treat municipal and industrial wastewater as well as stormwater runoff, they may play a role in water-sensitive urban design. A patch of land that develops pools of water after a rain storm would not be considered a "wetland" though the land is wet. Wetlands have unique characteristics: they are distinguished from other water bodies or landforms based on their water level and on the types of plants that live within them. Wetlands are characterized as having a water table that stands at or near the land surface for a long enough period each year to support aquatic plants.
A more concise definition is a community composed of hydric soil and hydrophytes. Wetlands have been described as ecotones, providing a transition between dry land and water bodies. Mitsch and Gosselink write that wetlands exist "...at the interface between terrestrial ecosystems and aquatic systems, making them inherently different from each other, yet dependent on both."In environmental decision-making, there are subsets of definitions that are agreed upon to make regulatory and policy decisions. A wetland is "an ecosystem that arises when inundation by water produces soils dominated by anaerobic and aerobic processes, which, in turn, forces the biota rooted plants, to adapt to flooding." There are four main kinds of wetlands – marsh, swamp and fen. Some experts recognize wet meadows and aquatic ecosystems as additional wetland types; the largest wetlands in the world include the swamp forests of the Amazon and the peatlands of Siberia. Under the Ramsar international wetland conservation treaty, wetlands are defined as follows: Article 1.1: "...wetlands are areas of marsh, peatland or water, whether natural or artificial, permanent or temporary, with water, static or flowing, brackish or salt, including areas of marine water the depth of which at low tide does not exceed six metres."
Article 2.1: " may incorporate riparian and coastal zones adjacent to the wetlands, islands or bodies of marine water deeper than six metres at low tide lying within the wetlands." Although the general definition given above applies around the world, each county and region tends to have its own definition for legal purposes. In the United States, wetlands are defined as "those areas that are inundated or saturated by surface or groundwater at a frequency and duration sufficient to support, that under normal circumstances do support, a prevalence of vegetation adapted for life in saturated soil conditions. Wetlands include swamps, marshes and similar areas"; this definition has been used in the enforcement of the Clean Water Act. Some US states, such as Massachusetts and New York, have separate definitions that may differ from the federal government's. In the United States Code, the term wetland is defined "as land that has a predominance of hydric soils, is inundated or saturated by surface or groundwater at a frequency and duration sufficient to support a prevalence of hydrophytic vegetation adapted for life in saturated soil conditions and under normal circumstances supports a prevalence of such vegetation."
Related to this legal definitions, the term "normal circumstances" are conditions expected to occur during the wet portion of the growing season under normal climatic conditions, in the absence of significant disturbance. It is not uncommon for a wetland to be dry for long portions of the growing season. Wetlands can be dry during the dry season and abnormally dry periods during the wet season, but under normal environmental conditions the soils in a wetland will be saturated to the surface or inundated such that the soils become anaerobic, those conditions will persist through the wet portion of the growing season; the most important factor producing wetlands is flooding. The duration of flooding or prolonged soil saturation by groundwater determines whether the resulting wetland has aquatic, marsh or swamp vegetation
Java is an island of Indonesia, bordered by the Indian Ocean on the south and the Java Sea on the north. With a population of over 141 million or 145 million, Java is the home to 56.7 percent of the Indonesian population and is the world's most populous island. The Indonesian capital city, Jakarta, is located on its northwestern coast. Much of Indonesian history took place on Java, it was the center of powerful Hindu-Buddhist empires, the Islamic sultanates, the core of the colonial Dutch East Indies. Java was the center of the Indonesian struggle for independence during the 1930s and 1940s. Java dominates Indonesia politically and culturally. Four of Indonesia's eight UNESCO world heritage sites are located in Java: Ujung Kulon National Park, Borobudur Temple, Prambanan Temple, Sangiran Early Man Site. Formed as the result of volcanic eruptions from geologic subduction between Sunda Plate and Australian Plate, Java is the 13th largest island in the world and the fifth largest in Indonesia by landmass at about 138,800 square kilometres.
A chain of volcanic mountains forms an east–west spine along the island. Three main languages are spoken on the island: Javanese and Madurese, where Javanese is the most spoken. Furthermore, most residents are bilingual, speaking Indonesian as their second language. While the majority of the people of Java are Muslim, Java's population comprises people of diverse religious beliefs and cultures. Java is divided into four administrative provinces, West Java, Central Java, East Java, Banten, two special regions and Yogyakarta; the origins of the name "Java" are not clear. One possibility is that the island was named after the jáwa-wut plant, said to be common in the island during the time, that prior to Indianization the island had different names. There are other possible sources: the word jaú and its variations mean "beyond" or "distant". And, in Sanskrit yava means barley, a plant for which the island was famous. "Yavadvipa" is mentioned in the Ramayana. Sugriva, the chief of Rama's army dispatched his men to Yavadvipa, the island of Java, in search of Sita.
It was hence referred to in India by the Sanskrit name "yāvaka dvīpa". Java is mentioned in the ancient Tamil text Manimekalai by Chithalai Chathanar that states that Java had a kingdom with a capital called Nagapuram. Another source states that the "Java" word is derived from a Proto-Austronesian root word, Iawa that meaning "home"; the great island of Iabadiu or Jabadiu was mentioned in Ptolemy's Geographia composed around 150 CE in the Roman Empire. Iabadiu is said to mean "barley island", to be rich in gold, have a silver town called Argyra at the west end; the name indicates Java, seems to be derived from the Sanskrit name Java-dvipa. The annual news of Songshu and Liangshu referred Java as She-po, He-ling called it She-po again until the Yuan dynasty, where they began mentioning Zhao-Wa. According to Ma Huan's book, the Chinese call Java as Chao-Wa, the island was called She-pó in the past; when John of Marignolli returned from China to Avignon, he stayed at the Kingdom of Saba for a few months, which he said had many elephants and led by a queen.
Java lies between Sumatra to Bali to the east. Borneo lies to the north and Christmas Island is to the south, it is the world's 13th largest island. Java is surrounded by the Java Sea to the north, Sunda Strait to the west, the Indian Ocean to the south and Bali Strait and Madura Strait in the east. Java is entirely of volcanic origin; the highest volcano in Java is Mount Semeru. The most active volcano in Java and in Indonesia is Mount Merapi. In total, Java boast more than 150 mountains. More mountains and highlands help to split the interior into a series of isolated regions suitable for wet-rice cultivation. Java was the first place where Indonesian coffee was grown, starting in 1699. Today, Coffea arabica is grown on the Ijen Plateau by larger plantations; the area of Java is 150,000 square kilometres. It is up to 210 km wide; the island's longest river is the 600 km long Solo River. The river rises from its source in central Java at the Lawu volcano flows north and eastward to its mouth in the Java Sea near the city of Surabaya.
Other major rivers are Brantas, Citarum and Serayu. The average temperature ranges from 22 °C to 29 °C; the northern coastal plains are hotter, averaging 34 °C during the day in the dry season. The south coast is cooler than the north, highland areas inland are cooler; the wet season ends in April. During that rain falls in the afternoons and intermittently during other parts of the year; the wettest months are February. West Java is wetter than East mountainous regions receive much higher rainfall; the Parahyangan highlands of West Java receive over 4,000 millimetres annually, while the north coast of East Java receives 900 millimetres annually. The natural environment of Jav
In chemistry, pH is a scale used to specify how acidic or basic a water-based solution is. Acidic solutions have a lower pH, while basic solutions have a higher pH. At room temperature, pure water is neither acidic nor basic and has a pH of 7; the pH scale is logarithmic and approximates the negative of the base 10 logarithm of the molar concentration of hydrogen ions in a solution. More it is the negative of the base 10 logarithm of the activity of the hydrogen ion. At 25 °C, solutions with a pH less than 7 are acidic and solutions with a pH greater than 7 are basic; the neutral value of the pH depends on the temperature, being lower than 7 if the temperature increases. Contrary to popular belief, the pH value can be less than 0 or greater than 14 for strong acids and bases respectively; the pH scale is traceable to a set of standard solutions whose pH is established by international agreement. Primary pH standard values are determined using a concentration cell with transference, by measuring the potential difference between a hydrogen electrode and a standard electrode such as the silver chloride electrode.
The pH of aqueous solutions can be measured with a glass electrode and a pH meter, or a color-changing indicator. Measurements of pH are important in chemistry, medicine, water treatment, many other applications; the concept of pH was first introduced by the Danish chemist Søren Peder Lauritz Sørensen at the Carlsberg Laboratory in 1909 and revised to the modern pH in 1924 to accommodate definitions and measurements in terms of electrochemical cells. In the first papers, the notation had the "H" as a subscript to the lowercase "p", as so: pH; the exact meaning of the "p" in "pH" is disputed, but according to the Carlsberg Foundation, pH stands for "power of hydrogen". It has been suggested that the "p" stands for the German Potenz, others refer to French puissance. Another suggestion is that the "p" stands for the Latin terms pondus hydrogenii, potentia hydrogenii, or potential hydrogen, it is suggested that Sørensen used the letters "p" and "q" to label the test solution and the reference solution.
In chemistry, the p stands for "decimal cologarithm of", is used in the term pKa, used for acid dissociation constants. Bacteriologist Alice C. Evans, famed for her work's influence on dairying and food safety, credited William Mansfield Clark and colleagues with developing pH measuring methods in the 1910s, which had a wide influence on laboratory and industrial use thereafter. In her memoir, she does not mention how much, or how little and colleagues knew about Sørensen's work a few years prior, she said: In these studies Dr. Clark's attention was directed to the effect of acid on the growth of bacteria, he found that it is the intensity of the acid in terms of hydrogen-ion concentration that affects their growth. But existing methods of measuring acidity determined not the intensity, of the acid. Next, with his collaborators, Dr. Clark developed accurate methods for measuring hydrogen-ion concentration; these methods replaced the inaccurate titration method of determining acid content in use in biologic laboratories throughout the world.
They were found to be applicable in many industrial and other processes in which they came into wide usage. The first electronic method for measuring pH was invented by Arnold Orville Beckman, a professor at California Institute of Technology in 1934, it was in response to local citrus grower Sunkist that wanted a better method for testing the pH of lemons they were picking from their nearby orchards. PH is defined as the decimal logarithm of the reciprocal of the hydrogen ion activity, aH+, in a solution. PH = − log 10 = log 10 For example, for a solution with a hydrogen ion activity of 5×10−6 we get 1/ = 2×105, thus such a solution has a pH of log10 = 5.3. For a commonplace example based on the facts that the masses of a mole of water, a mole of hydrogen ions, a mole of hydroxide ions are 18 g, 1 g, 17 g, a quantity of 107 moles of pure water, or 180 tonnes, contains close to 1 g of dissociated hydrogen ions and 17 g of hydroxide ions. Note that pH depends on temperature. For instance at 0 °C the pH of pure water is 7.47.
At 25 °C it's 7.00, at 100 °C it's 6.14. This definition was adopted because ion-selective electrodes, which are used to measure pH, respond to activity. Ideally, electrode potential, E, follows the Nernst equation, for the hydrogen ion can be written as E = E 0 + R T F ln = E 0 − 2.303 R T F pH where E is a measured potential, E0 is the standard electrode potential, R is the gas const