query: who discovered that atoms combine in whole number ratios

pos: Law of multiple proportions Law of multiple proportions In chemistry, the law of multiple proportions is one of the basic laws of stoichiometry used to establish the atomic theory, alongside the law of conservation of mass (matter) and the law of definite proportions. It is sometimes called Dalton's Law after its discoverer, the British chemist John Dalton, who published it in the first part of the first volume of his "New System of Chemical Philosophy" (1808). Here is the statement of the law: For example, Dalton knew that the element carbon forms two oxides by combining with oxygen in different proportions. A fixed mass

pos: Chemistry: A Volatile History elements? Scientists had recently discovered that when elements combine to form compounds, they always do so in the same proportions, by weight. John Dalton thought that for this to happen, each element had to be made of its own unique building blocks, which he called atoms. Dalton suggested that everything in the universe was made of atoms, and that there are as many kinds of atoms as there are elements, each one with its own signature weight. Based on these ideas, working completely alone, Dalton attempted to impose some order on the elements by drawing up a list, where each

pos: Atom theory of atoms was popularized in France by the physician François Bernier (1620–1688) and in England by the natural philosopher Walter Charleton (1619–1707). The chemist Robert Boyle (1627–1691) and the physicist Isaac Newton (1642–1727) both defended atomism and, by the end of the seventeenth century, it had become accepted by portions of the scientific community. In the early 1800s, John Dalton used the concept of atoms to explain why elements always react in ratios of small whole numbers (the law of multiple proportions). For instance, there are two types of tin oxide: one is 88.1% tin and 11.9% oxygen and

pos: Law of definite proportions fellow Frenchman Claude Louis Berthollet, who argued that the elements could combine in any proportion. The existence of this debate demonstrates that, at the time, the distinction between pure chemical compounds and mixtures had not yet been fully developed. The law of definite proportions contributed to, and was placed on a firm theoretical basis by, the atomic theory that John Dalton promoted beginning in 1803, which explained matter as consisting of discrete atoms, that there was one type of atom for each element, and that the compounds were made of combinations of different types of atoms in fixed proportions. A

pos: Whole number rule whole-number rule." The law of definite proportions was formulated by Joseph Proust around 1800 and states that all samples of a chemical compound will have the same elemental composition by mass. The atomic theory of John Dalton expanded this concept and explained matter as consisting of discrete atoms with one kind of atom for each element combined in fixed proportions to form compounds. In 1815, William Prout reported on his observation that the atomic weights of the elements were whole multiples of the atomic weight of hydrogen. He then hypothesized that the hydrogen atom was the fundamental object and that

pos: Chemistry day. Before his work, though, many important discoveries had been made, specifically relating to the nature of 'air' which was discovered to be composed of many different gases. The Scottish chemist Joseph Black (the first experimental chemist) and the Dutchman J.B. van Helmont discovered carbon dioxide, or what Black called 'fixed air' in 1754; Henry Cavendish discovered hydrogen and elucidated its properties and Joseph Priestley and, independently, Carl Wilhelm Scheele isolated pure oxygen. English scientist John Dalton proposed the modern theory of atoms; that all substances are composed of indivisible 'atoms' of matter and that different atoms have varying atomic

pos: Diatomic molecule of the order of parts per million, but H is the most abundant diatomic molecule in the universe. The interstellar medium is, indeed, dominated by hydrogen atoms. Diatomic elements played an important role in the elucidation of the concepts of element, atom, and molecule in the 19th century, because some of the most common elements, such as hydrogen, oxygen, and nitrogen, occur as diatomic molecules. John Dalton's original atomic hypothesis assumed that all elements were monatomic and that the atoms in compounds would normally have the simplest atomic ratios with respect to one another. For example, Dalton assumed water's formula

neg: History of chemistry and Dalton included a clear description of the law in his "New System of Chemical Philosophy". The law of multiple proportions is one of the basic laws of stoichiometry used to establish the atomic theory. Despite the importance of the work as the first view of atoms as physically real entities and introduction of a system of chemical symbols, "New System of Chemical Philosophy" devoted almost as much space to the caloric theory as to atomism. French chemist Joseph Proust proposed the law of definite proportions, which states that elements always combine in small, whole number ratios to form compounds,

neg: The Structure of Scientific Revolutions completely upon distillation (they form an azeotrope). Water and alcohol can be combined in any proportion. Under this paradigm, scientists believed that chemical reactions (such as the combination of water and alcohol) did not necessarily occur in fixed proportion. This belief was ultimately overturned by Dalton’s atomic theory, which asserted that atoms can only combine in simple, whole-number ratios. Under this new paradigm, any reaction which did not occur in fixed proportion could not be a chemical process. This type world-view transition among the scientific community exemplifies Kuhn's paradigm shift. A famous example of a revolution in scientific thought is

neg: John Dalton multiple proportions appears to be anticipated in the words: But there is reason to suspect that this sentence may have been added some time after the reading of the paper, which was not published until 1805. Compounds were listed as binary, ternary, quaternary, etc. (molecules composed of two, three, four, etc. atoms) in the "New System of Chemical Philosophy" depending on the number of atoms a compound had in its simplest, empirical form. Dalton hypothesised the structure of compounds can be represented in whole number ratios. So, one atom of element X combining with one atom of element Y is

neg: Formula |}{\underset{\underset{\underset{| \atop \displaystyle H}{C}}-H</chem>|caption=The structural formula for butane. There are three common non-pictorial types of chemical formulas for this molecule: A chemical formula identifies each constituent element by its chemical symbol and indicates the proportionate number of atoms of each element. In empirical formulas, these proportions begin with a key element and then assign numbers of atoms of the other elements in the compound, as ratios to the key element. For molecular compounds, these ratio numbers can all be expressed as whole numbers. For example, the empirical formula of ethanol may be written CHO because the molecules of ethanol all

neg: Atom the other is 78.7% tin and 21.3% oxygen (tin(II) oxide and tin dioxide respectively). This means that 100g of tin will combine either with 13.5g or 27g of oxygen. 13.5 and 27 form a ratio of 1:2, a ratio of small whole numbers. This common pattern in chemistry suggested to Dalton that elements react in multiples of discrete units — in other words, atoms. In the case of tin oxides, one tin atom will combine with either one or two oxygen atoms. Dalton also believed atomic theory could explain why water absorbs different gases in different proportions. For example, he

neg: Discovery of the neutron radioactivity and the discovery of isotopes, Soddy was awarded the 1921 Nobel Prize in Chemistry. Building from work by J. J. Thomson on the deflection of positively charged atoms by electric and magnetic fields, Francis Aston built the first mass spectrograph at the Cavendish Laboratory in 1919. His aim was to try to separate the two isotopes of neon, which he was able to easily do. Aston discovered that the masses of all the particles are whole numbers, called the whole number rule, that is, the masses of all the isotopes are whole number multiples of the mass of the

neg: Geiger–Marsden experiment atomic weight (Geiger and Marsden knew that for foils of equal stopping power, the number of atoms per unit area is proportional to the square root of the atomic weight). Thus, for each metal, Geiger and Marsden obtained the number of scintillations that a fixed number of atoms produce. For each metal, they then divided this number by the square of the atomic weight, and found that the ratios were more or less the same. Thus they proved that "s ∝ Q". Finally, Geiger and Marsden tested how the scattering varied with the velocity of the alpha particles (i.e. if

neg: John Dalton of Gases by Water and other Liquids" already mentioned. There he says: The main points of Dalton's atomic theory are: Dalton proposed an additional controversial "rule of greatest simplicity" that could not be independently confirmed. For elements that combined in multiple ratios, their combinations were assumed to be the simplest ones possible. Two combinations resulted in a binary and a ternary compound. This was merely an assumption, derived from faith in the simplicity of nature. No evidence was then available to scientists to deduce how many atoms of each element combine to form compound molecules. But this or some other

neg: Noble gas these interactions became tractable because the noble gases are monatomic and the atoms spherical, which means that the interaction between the atoms is independent of direction, or isotropic. The noble gases are colorless, odorless, tasteless, and nonflammable under standard conditions. They were once labeled "group 0" in the periodic table because it was believed they had a valence of zero, meaning their atoms cannot combine with those of other elements to form compounds. However, it was later discovered some do indeed form compounds, causing this label to fall into disuse. Like other groups, the members of this family show patterns

neg: Amorphous carbon owing to the tetrahedral shape formed by "sp" hybridized bonds, or as diamond-like carbon (owing to the similarity of many physical properties to those of diamond). Experimentally, sp to sp ratios can be determined by comparing the relative intensities of various spectroscopic peaks (including EELS, XPS, and Raman spectroscopy) to those expected for graphite or diamond. In theoretical works, the "sp" to "sp" ratios are often obtained by counting the number of carbon atoms with three bonded neighbors versus those with four bonded neighbors. (This technique requires deciding on a somewhat arbitrary metric for determining whether neighboring atoms are considered

neg: Heat capacity other words; even though an ingot of arsenic is only about 17% larger than an antimony one of the same mass, it absorbs about 59% more heat for a given temperature rise. The heat capacity ratios of the two substances closely follows the ratios of their molar volumes (the ratios of numbers of atoms in the same volume of each substance); the departure from the correlation to simple volumes in this case is due to lighter arsenic atoms being significantly more closely packed than antimony atoms, instead of similar size. In other words, similar-sized atoms would cause a mole of

neg: Irrational number reduced to whole numbers and their ratios.” Another legend states that Hippasus was merely exiled for this revelation. Whatever the consequence to Hippasus himself, his discovery posed a very serious problem to Pythagorean mathematics, since it shattered the assumption that number and geometry were inseparable–a foundation of their theory. The discovery of incommensurable ratios was indicative of another problem facing the Greeks: the relation of the discrete to the continuous. Brought into light by Zeno of Elea, who questioned the conception that quantities are discrete and composed of a finite number of units of a given size. Past Greek conceptions

neg: Chemistry: A Volatile History chemist Henry Moseley speculated that the answer to the number of protons lay in the nucleus. By firing a radioactive source at copper, he was able to knock electrons from their atoms, releasing a burst of energy in the form of an x-ray. When measured, the x-rays always had the same energy, unique to copper. He discovered each element released x-rays of different energies. Moseley's brilliance was to realise the x-ray energy is related to the number of protons inside the atom: the atomic number. Because this is the number of protons, the atomic number must be a whole number

neg: Richard Smoley primitive intelligence. Look at the thousands of ways in which atoms of hydrogen combine with those of other elements, forming the most diverse substances. Do you mean to say that they do this without intelligence?...Gathered together in certain forms, the atoms constitute animals of the lower orders. Finally they combine in man, who represents the total intelligence of all the atoms.” Smoley adds, “If an atom could not take a stance in the physical world and draw a line between itself and what is not itself, it could not exist.” Smoley characterizes human consciousness in terms of his contrast of

neg: Whole number rule the other elements were a combination of different numbers of hydrogen atoms. In 1920, Francis W. Aston demonstrated through the use of a mass spectrometer that apparent deviations from Prout's hypothesis are predominantly due to the existence of isotopes. These deviations are secondarily due to binding energy, as mass defect. During the 1920s, it was thought that the atomic nucleus was made of protons and electrons, which would account for the disparity between the atomic number of an atom and its atomic mass. In 1932, James Chadwick discovered an uncharged particle of approximately the mass as the proton, which he

neg: Magnetic resonance (quantum mechanics) in that state from all previous intervals, so the number of atoms in state 2 is formula_57; The rate of decay of atoms from state two is proportional to the number of atoms present in that state, while the constant of proportionality is decay constant formula_58 . Performing the integration rate of decay of atoms from state two is obtained as: From this expression many interesting points can be exploited, such The existence of spin angular momentum of electrons was discovered experimentally by the Stern–Gerlach experiment. In that study a beam of neutral atoms with one electron in the valence

neg: Metallicity mass that is attributed to gas versus metals, or measuring the ratios of the number of atoms of two different elements as compared to the ratios found in the Sun. Stellar composition is often simply defined by the parameters "X", "Y" and "Z". Here "X" is the mass fraction of hydrogen, "Y" is the mass fraction of helium, and "Z" is the mass fraction of all the remaining chemical elements. Thus In most stars, nebulae, H II regions, and other astronomical sources, hydrogen and helium are the two dominant elements. The hydrogen mass fraction is generally expressed as formula_2, where

neg: History of molecular theory and renaissance Europe. A modern conceptualization of molecules began to develop in the 19th century along with experimental evidence for pure chemical elements and how individual atoms of different chemical substances such as hydrogen and oxygen can combine to form chemically stable molecules such as water molecules. The earliest views on the shapes and connectivity of atoms was that proposed by Leucippus, Democritus, and Epicurus who reasoned that the solidness of the material corresponded to the shape of the atoms involved. Thus, iron atoms are solid and strong with hooks that lock them into a solid; water atoms are smooth

neg: Volumetric heat capacity two substances closely follows the ratios of their molar volumes (the ratios of numbers of atoms in the same volume of each substance); the departure from the correlation to simple volumes in this case is due to lighter arsenic atoms being significantly more closely packed than antimony atoms, instead of similar size. In other words, similar-sized atoms would cause a mole of arsenic to be 63% larger than a mole of antimony, with a correspondingly lower density, allowing its volume to more closely mirror its heat capacity behavior. "Thermal inertia" is a term commonly used for modelling heat transfers. It

neg: Atomas player to combine two unlike atoms (opposed to two like atoms with the regular plus orb). Additionally, neutrinos spawn with a 1/60 chance after a score of 1500, and makes a copy of any orb on the board that you choose. Lucky charms are unlocked as the player advances and grant bonuses such as increasing the number of plus atoms. The game ends when the game board is full and can no longer place any new elements. In addition to the Classic game mode as described above there are also Time Attack, Zen and Geneva modes. In the Time Attack

neg: Atomic ratio the "atomic ratio" of hydrogen to oxygen is . Another application is in radiochemistry, where this may refer to isotopic ratios or isotopic abundances. Mathematically, the "isotopic abundance" is where "N" are the number of atoms of the isotope of interest and "N" is the total number of atoms, while the "atomic ratio" is For example, the "isotopic ratio" of deuterium (D) to hydrogen (H) in heavy water is roughly (corresponding to an "isotopic abundance" of 0.00014%). In laser physics however, the "atomic ratio" may refer to the doping ratio or the doping fraction. Atomic ratio The atomic ratio is

neg: Introduction to quantum mechanics direction is arbitrary, conventionally the z-direction is chosen. The fourth quantum number, the [[spin quantum number]] (pertaining to the "orientation" of the electron's spin) is denoted , with values + or −. The chemist [[Linus Pauling]] wrote, by way of example: It is the underlying structure and symmetry of atomic orbitals, and the way that electrons fill them, that leads to the organisation of the [[periodic table]]. The way the atomic orbitals on different atoms combine to form [[molecular orbital]]s determines the structure and strength of chemical bonds between atoms. [[File:Dirac 3.jpg|upright|thumb|right|[[Paul Dirac]] (1902–1984)]] In 1928, [[Paul Dirac]] extended the

neg: Uranium-238 particles per second, producing the same number of thorium-234 (Th-234) atoms. In a closed system an equilibrium would be reached, with all amounts except for lead-206 and U in fixed ratios, in slowly decreasing amounts. The amount of Pb-206 will increase accordingly while that of U decreases; all steps in the decay chain have this same rate of 3 decayed particles per second per mole U. Thorium-234 has a mean lifetime of 3 seconds, so there is equilibrium if one mole of U contains 9 atoms of thorium-234, which is 1.5 mole (the ratio of the two half-lives). Similarly, in

neg: Formula contain two carbon atoms, six hydrogen atoms, and one oxygen atom. Some types of ionic compounds, however, cannot be written with entirely whole-number empirical formulas. An example is boron carbide, whose formula of CB is a variable non-whole number ratio with n ranging from over 4 to more than 6.5. When the chemical compound of the formula consists of simple molecules, chemical formulas often employ ways to suggest the structure of the molecule. There are several types of these formulas, including molecular formulas and condensed formulas. A molecular formula enumerates the number of atoms to reflect those in the molecule,

neg: Quantity In his "Elements", Euclid developed the theory of ratios of magnitudes without studying the nature of magnitudes, as Archimedes, but giving the following significant definitions: For Aristotle and Euclid, relations were conceived as whole numbers (Michell, 1993). John Wallis later conceived of ratios of magnitudes as real numbers as reflected in the following: That is, the ratio of magnitudes of any quantity, whether volume, mass, heat and so on, is a number. Following this, Newton then defined number, and the relationship between quantity and number, in the following terms: "By "number" we understand not so much a multitude of unities,

neg: Edward Frankland be derived by the substitution of an organic group for the oxygen, sulphur, &c. In this way they enabled him to overthrow the theory of conjugate compounds, and they further led him in 1852 to publish the conception that the atoms of each elementary substance have a definite saturation capacity, so that they can only combine with a certain limited number of the atoms of other elements. The theory of valency thus founded has dominated the subsequent development of chemical doctrine, and forms the groundwork upon which the fabric of modern structural chemistry reposes. Edward Frankland's 1852 publication on his

neg: Ratio ratio and "" ("proportionality") for the equality of ratios. Euclid collected the results appearing in the Elements from earlier sources. The Pythagoreans developed a theory of ratio and proportion as applied to numbers. The Pythagoreans' conception of number included only what would today be called rational numbers, casting doubt on the validity of the theory in geometry where, as the Pythagoreans also discovered, incommensurable ratios (corresponding to irrational numbers) exist. The discovery of a theory of ratios that does not assume commensurability is probably due to Eudoxus of Cnidus. The exposition of the theory of proportions that appears in Book

neg: Silanylidene group atoms is known as the silicon skeleton or silicon backbone. The simplest possible silanylidene group (the parent functional group) is silylidene, . There is no limit to the number of silicon atoms that can be linked together, the only limitation being that the functional group is acyclic, is saturated, and is a hydrosilicon. Saturated hydrosilicon functional groups with a double joining bond, can be: According to the definition by IUPAC, the former two are silanylidene groups, whereas the third group is called cyclosilanylidene groups. Saturated hydrosilicon functional groups with a double joining bond can also combine any of the linear,

neg: VSEPR theory central atoms participate in bonding to two or more other atoms; the geometry of these key atoms and their non-bonding electron pairs in turn determine the geometry of the larger whole. The number of electron pairs in the valence shell of a central atom is determined after drawing the Lewis structure of the molecule, and expanding it to show all bonding groups and lone pairs of electrons. In VSEPR theory, a double bond or triple bond are treated as a single bonding group. The sum of the number of atoms bonded to a central atom and the number of lone

neg: Chemical formula a different connectivity from other molecules that can be formed using the same atoms in the same proportions (isomers). The formula (CH)CH implies a central carbon atom connected to one hydrogen atom and three CH groups. The same number of atoms of each element (10 hydrogens and 4 carbons, or CH) may be used to make a straight chain molecule, "n"-butane: CHCHCHCH. In any given chemical compound, the elements always combine in the same proportion with each other. This is the law of constant composition. The law of constant composition says that, in any particular chemical compound, all samples of

neg: SMILES arbitrary target specification to encode pharmacophore elements such as anionic centers. In the following example, recursive SMARTS notation is used to combine acid oxygen and tetrazole nitrogen in a definition of oxygen atoms that are likely to be anionic under normal physiological conditions. The SMARTS above would only match the acid hydroxyl and the tetrazole N−H. When a carboxylic acid deprotonates the negative charge is delocalised over both oxygen atoms and it may be desirable to designate both as anionic. This can achieved using the following SMARTS. The precise and transparent substructural specification that SMARTS allows has been exploited in a number of

neg: Aspect ratio of 1:1 is a circle. In geometry, there are several alternative definitions to aspect ratios of general compact sets in a d-dimensional space: If the dimension d is fixed, then all reasonable definitions of aspect ratio are equivalent to within constant factors. Aspect ratios are mathematically expressed as "x":"y" (pronounced "x-to-y"). Cinematographic aspect ratios are usually denoted as a (rounded) decimal multiple of width vs unit height, while photographic and videographic aspect ratios are usually defined and denoted by whole number ratios of width to height. In digital images there is a subtle distinction between the "display" aspect ratio (the

neg: Mass (mass spectrometry) stable nucleus. The nitrogen rule states that organic compounds containing exclusively hydrogen, carbon, nitrogen, oxygen, silicon, phosphorus, sulfur, and the halogens either have an odd nominal mass that indicates an odd number of nitrogen atoms are present or an even nominal mass that indicates an even number of nitrogen atoms are present in the molecular ion. The whole number rule states that the masses of the isotopes are integer multiples of the mass of the hydrogen atom. The rule is a modified version of Prout's hypothesis proposed in 1815, to the effect that atomic weights are multiples of the weight

neg: History of chemistry which he later analyzed chemically. In 1808 Gay-Lussac announced what was probably his single greatest achievement: from his own and others' experiments he deduced that gases at constant temperature and pressure combine in simple numerical proportions by volume, and the resulting product or products—if gases—also bear a simple proportion by volume to the volumes of the reactants. In other words, gases under equal conditions of temperature and pressure react with one another in volume ratios of small whole numbers. This conclusion subsequently became known as "Gay-Lussac's law" or the "Law of Combining Volumes". With his fellow professor at the École

neg: Redfield ratio which nutrients are limiting in a localized system, if there is a limiting nutrient. The ratio can also be used to understand the formation of phytoplankton blooms and subsequently hypoxia by comparing the ratio between different regions, such as a comparison of the Redfield Ratio of the Mississippi River to the ratio of the northern Gulf of Mexico. Redfield discovered the remarkable congruence between the chemistry of the deep ocean and the chemistry of living things such as phytoplankton in the surface ocean. Both have N:P ratios of about 16:1 in terms of atoms. When nutrients are not limiting, the

neg: Superpartient ratio formula_2 are also greater than one and fully reduced, but are called superparticular ratios and are not superpartient. "Superpartient" comes from Greek ἐπιμερής "epimeres" "containing a whole and a fraction," literally "superpartient". Superpartient ratio In mathematics, a superpartient ratio, also called superpartient number or epimoric ratio, is a rational number that is greater than one and is not superparticular. The term has fallen out of use in modern pure mathematics, but continues to be used in music theory and in the historical study of mathematics. Superpartient ratios were written about by Nicomachus in his treatise "Introduction to Arithmetic". Mathematically, a

neg: Valence bond theory Valence bond theory In chemistry, valence bond (VB) theory is one of two basic theories, along with molecular orbital (MO) theory, that were developed to use the methods of quantum mechanics to explain chemical bonding. It focuses on how the atomic orbitals of the dissociated atoms combine to give individual chemical bonds when a molecule is formed. In contrast, molecular orbital theory has orbitals that cover the whole molecule. In 1916, G. N. Lewis proposed that a chemical bond forms by the interaction of two shared bonding electrons, with the representation of molecules as Lewis structures. In 1927 the Heitler–London

neg: Ājīvika mere juxtapositions of atoms of various types, and the combinations occur always in fixed ratios governed by certain cosmic rules, forming "skandha" (molecules, building blocks). Atoms, asserted the Ajivikas, cannot be seen by themselves in their pure state, but only when they aggregrate and form "bhutas" (objects). They further argued that properties and tendencies are characteristics of the objects. The Ajivikas then proceeded to justify their belief in determinism and "no free will" by stating that everything experienced – "sukha" (joy), "dukkha" (sorrow) and "jiva" (life) – is mere function of atoms operating under cosmic rules. Riepe states that the

neg: Deuterium abundance of deuterium in the atmosphere of Jupiter has been directly measured by the Galileo space probe as 26 atoms per million hydrogen atoms. ISO-SWS observations find 22 atoms per million hydrogen atoms in Jupiter. and this abundance is thought to represent close to the primordial solar system ratio. This is about 17% of the terrestrial deuterium-to-hydrogen ratio of 156 deuterium atoms per million hydrogen atoms. Cometary bodies such as Comet Hale-Bopp and Halley's Comet have been measured to contain relatively more deuterium (about 200 atoms D per million hydrogens), ratios which are enriched with respect to the presumed protosolar

neg: Ozone depletion an ozone layer in the Earth's stratosphere were discovered by Sydney Chapman in 1930. Short-wavelength UV radiation splits an oxygen () molecule into two oxygen (O) atoms, which then combine with other oxygen molecules to form ozone. Ozone is removed when an oxygen atom and an ozone molecule "recombine" to form two oxygen molecules, i.e. O + → 2. In the 1950s, David Bates and Marcel Nicolet presented evidence that various free radicals, in particular hydroxyl (OH) and nitric oxide (NO), could catalyze this recombination reaction, reducing the overall amount of ozone. These free radicals were known to be present

neg: Diagnostic odds ratio test: It may also be expressed in terms of the Positive predictive value (PPV) and Negative predictive value (NPV): It is also related to the likelihood ratios, formula_10 and formula_11: The log diagnostic odds ratio is sometimes used in meta-analyses of diagnostic test accuracy studies due to its simplicity (being approximately normally distributed). Traditional meta-analytic techniques such as inverse-variance weighting can be used to combine log diagnostic odds ratios computed from a number of data sources to produce an overall diagnostic odds ratio for the test in question. The log diagnostic odds ratio can also be used to study the

neg: Plasma recombination present time, it is believed that the most likely plasma losses observed in the recombining region are due to two different modes: electron ion recombination (EIR) and molecular activated recombination (MAR). Plasma recombination Plasma recombination is a process by which positive ions of a plasma capture a free (energetic) electron and combine with electrons or negative ions to form new neutral atoms (gas). Recombination is an exothermic reaction, meaning heat releasing. Recombination usually takes place in the whole volume of a plasma (volume recombination), although in some cases it is confined to some special region of it. Each kind of

neg: Hindu philosophy of two types: atomic (paramāṇu) and composite. An atom is, according to Vaiśeṣika scholars, that which is indestructible (anitya), indivisible, and has a special kind of dimension, called “small” (aṇu). A composite, in this philosophy, is defined to be anything which is divisible into atoms. Whatever human beings perceive is composite, while atoms are invisible. The Vaiśeṣikas stated that size, form, truths and everything that human beings experience as a whole is a function of atoms, their number and their spatial arrangements, their guṇa (quality), "karma" (activity), "sāmānya" (commonness), "viśeṣa" (particularity) and "amavāya" (inherence, inseparable connectedness of everything). The Nyāya

neg: Chemistry valence electrons are shared by two atoms: the resulting electrically neutral group of bonded atoms is termed a molecule. Atoms will share valence electrons in such a way as to create a noble gas electron configuration (eight electrons in their outermost shell) for each atom. Atoms that tend to combine in such a way that they each have eight electrons in their valence shell are said to follow the octet rule. However, some elements like hydrogen and lithium need only two electrons in their outermost shell to attain this stable configuration; these atoms are said to follow the "duet rule",

neg: Atom majority of atoms combine to form various compounds, including water, salt, silicates and oxides. Atoms can also combine to create materials that do not consist of discrete molecules, including crystals and liquid or solid metals. This atomic matter forms networked arrangements that lack the particular type of small-scale interrupted order associated with molecular matter. While isotopes with atomic numbers higher than lead (82) are known to be radioactive, an "island of stability" has been proposed for some elements with atomic numbers above 103. These superheavy elements may have a nucleus that is relatively stable against radioactive decay. The most likely

neg: History of optics basic atoms are those of earth ("prthivı"), water ("apas"), fire ("tejas"), and air ("vayu"), that should not be confused with the ordinary meaning of these terms. These atoms are taken to form binary molecules that combine further to form larger molecules. Motion is defined in terms of the movement of the physical atoms. Light rays are taken to be a stream of high velocity of "tejas" (fire) atoms. The particles of light can exhibit different characteristics depending on the speed and the arrangements of the "tejas" atoms. Around the first century BC, the "Vishnu Purana" refers to sunlight as "the

neg: Sympathetic cooling Sympathetic cooling Sympathetic cooling is a process in which particles of one type cool particles of another type. Typically, atomic ions that can be directly laser cooled are used to cool nearby ions or atoms, by way of their mutual Coulomb interaction. This technique allows cooling of ions and atoms that can't be cooled directly by laser cooling. This includes most molecular ion species, especially large organic molecules. However, sympathetic cooling is most efficient when the mass/charge ratios of the sympathetic- and laser-cooled ions are similar. The cooling of neutral atoms in this manner was first demonstrated by Christopher Myatt

neg: Mass spectrum all atoms (including isotopes) follow a whole-number rule This implied that the masses of atoms were not on a scale but could be expressed as integers. (In fact multiply charged ions were rare, so for the most part the ratio was whole as well.) There have been several suggestions (e.g. the unit thomson) to change the official mass spectrometry nomenclature formula_2 to be more internally consistent. The "y"-axis of a mass spectrum represents signal intensity of the ions. When using counting detectors the intensity is often measured in counts per second (cps). When using analog detection electronics the intensity is

neg: Matter and antileptons". The connection between these formulations follows. Leptons (the most famous being the electron), and quarks (of which baryons, such as protons and neutrons, are made) combine to form atoms, which in turn form molecules. Because atoms and molecules are said to be matter, it is natural to phrase the definition as: "ordinary matter is anything that is made of the same things that atoms and molecules are made of". (However, notice that one also can make from these building blocks matter that is "not" atoms or molecules.) Then, because electrons are leptons, and protons, and neutrons are made

neg: Menelaus's theorem the product of the three ratios is 1: which is equivalent to the given equation. It is uncertain who actually discovered the theorem; however, the oldest extant exposition appears in "Spherics" by Menelaus. In this book, the plane version of the theorem is used as a lemma to prove a spherical version of the theorem. In Almagest, Ptolemy applies the theorem on a number of problems in spherical astronomy. During the Islamic Golden Age, Muslim scholars devoted a number of works that engaged in the study of Menelaus's theorem, which they referred to as "the proposition on the secants" ("shakl

neg: Chemical element whole number. For example, the relative atomic mass of chlorine is 35.453 u, which differs greatly from a whole number as it is an average of about 76% chlorine-35 and 24% chlorine-37. Whenever a relative atomic mass value differs by more than 1% from a whole number, it is due to this averaging effect, as significant amounts of more than one isotope are naturally present in a sample of that element. Chemists and nuclear scientists have different definitions of a "pure element". In chemistry, a pure element means a substance whose atoms all (or in practice almost all) have the

neg: Tanmatras to form the Mahabhutas; atoms and suksma bhutas cannot exist in the phenomenal state in an uncombined form. Two panus or paramanus (atoms) combine as a result of parispanda (rotary or vibratory motion) to form a dvyanuka (molecule), three of these dvyanukas combine to form a tryanuka, and so on till heavier metals are formed. Except akasha, all other tanmatras have attributes of the previous ones in the succeeding ones. The tanmatras are quanta of energy. The total sattwik aspects of the five tanmatras combine to form the antah-karana or inner-instrument consisting of manas, buddhi, citta and ahamkara; the individual

neg: Big Bang nucleosynthesis of deuterium and helium-3, trace amounts (on the order of 10) of lithium, and negligible heavier elements. That the observed abundances in the universe are generally consistent with these abundance numbers is considered strong evidence for the Big Bang theory. In this field, for historical reasons it is customary to quote the helium-4 fraction "by mass", symbol Y, so that 25% helium-4 means that helium-4 atoms account for 25% of the mass, but less than 8% of the nuclei would be helium-4 nuclei. Other (trace) nuclei are usually expressed as number ratios to hydrogen. The creation of light elements during

neg: Rust rust. Only iron or alloys that contain iron can rust, but other metals can corrode in similar ways. The main catalyst for the rusting process is water. Iron or steel structures might appear to be solid, but water molecules can penetrate the microscopic pits and cracks in any exposed metal. The hydrogen atoms present in water molecules can combine with other elements to form acids, which will eventually cause more metal to be exposed. If chloride ions are present, as is the case with saltwater, the corrosion is likely to occur more quickly. Meanwhile, the oxygen atoms combine with metallic

neg: Alkane whereas the third group is called cycloalkanes. Saturated hydrocarbons can also combine any of the linear, cyclic (e.g., polycyclic) and branching structures; the general formula is , where "k" is the number of independent loops. Alkanes are the acyclic (loopless) ones, corresponding to "k" = 0. Alkanes with more than three carbon atoms can be arranged in various different ways, forming structural isomers. The simplest isomer of an alkane is the one in which the carbon atoms are arranged in a single chain with no branches. This isomer is sometimes called the "n"-isomer ("n" for "normal", although it is not

neg: Atomas in the center of the board instead of an atom. The plus orb allows the player to combine two like atoms into an element with a greater atomic number. Chain reactions can be formed by having the same atoms on either side of where the player places the plus orb. The minus orb allows the player to move an atom to a different location of the board or be converted into a plus orb if the player chooses. Occasionally there are black plus orbs (Dark Plus) which spawn with a 1/90 chance after a score of 750 and allow the

neg: Atomic mass strongly-bound compared with other atoms, the mass defect of binding for most atoms is an even smaller fraction of a dalton (unified atomic mass unit, based on carbon-12). Since free protons and neutrons differ from each other in mass by a small fraction of a dalton (about 0.0014 u), rounding the relative isotopic mass, or the atomic mass of any given nuclide given in daltons to the nearest whole number always gives the nucleon count, or mass number. Additionally, the neutron count (neutron number) may then be derived by subtracting the number of protons (atomic number) from the mass number

neg: Irrational number During the 14th to 16th centuries, Madhava of Sangamagrama and the Kerala school of astronomy and mathematics discovered the infinite series for several irrational numbers such as "π" and certain irrational values of trigonometric functions. Jyeṣṭhadeva provided proofs for these infinite series in the "Yuktibhāṣā". In the Middle ages, the development of algebra by Muslim mathematicians allowed irrational numbers to be treated as "algebraic objects". Middle Eastern mathematicians also merged the concepts of "number" and "magnitude" into a more general idea of real numbers, criticized Euclid's idea of ratios, developed the theory of composite ratios, and extended the concept of

neg: Molecular orbital diagram Molecular orbital diagram A molecular orbital diagram, or MO diagram, is a qualitative descriptive tool explaining chemical bonding in molecules in terms of molecular orbital theory in general and the linear combination of atomic orbitals (LCAO) molecular orbital method in particular. A fundamental principle of these theories is that as atoms bond to form molecules, a certain number of atomic orbitals combine to form the same number of molecular orbitals, although the electrons involved may be redistributed among the orbitals. This tool is very well suited for simple diatomic molecules such as dihydrogen, dioxygen, and carbon monoxide but becomes more

neg: Plasma recombination Plasma recombination Plasma recombination is a process by which positive ions of a plasma capture a free (energetic) electron and combine with electrons or negative ions to form new neutral atoms (gas). Recombination is an exothermic reaction, meaning heat releasing. Recombination usually takes place in the whole volume of a plasma (volume recombination), although in some cases it is confined to some special region of it. Each kind of reaction is called a recombining mode and their individual rates are strongly affected by the properties of the plasma such as its energy (heat), density of each species, pressure and temperature

neg: Hydrogen spectral series values are returned only when is greater than . Note that this equation is valid for all hydrogen-like species, i.e. atoms having only a single electron, and the particular case of hydrogen spectral lines are given by Z=1. In the Bohr model, the Lyman series includes the lines emitted by transitions of the electron from an outer orbit of quantum number n > 1 to the 1st orbit of quantum number n' = 1. The series is named after its discoverer, Theodore Lyman, who discovered the spectral lines from 1906–1914. All the wavelengths in the Lyman series are in the

neg: Leclanché cell cell begins when zinc atoms on the surface of the anode oxidize, i.e. they give up both their valence electrons to become positively charged Zn ions. As the Zn ions move away from the anode, leaving their electrons on its surface, the anode becomes more negatively charged than the cathode. When the cell is connected in an external electrical circuit, the excess electrons on the zinc anode flow through the circuit to the carbon rod, the movement of electrons forming an electric current. After passing through the whole circuit, when the electrons enter the cathode (carbon rod), they combine with

neg: Deuterium is produced. Other natural processes are thought to produce only an insignificant amount of deuterium. Nearly all deuterium found in nature was produced in the Big Bang 13.8 billion years ago, as the basic or primordial ratio of hydrogen-1 to deuterium (about 26 atoms of deuterium per million hydrogen atoms) has its origin from that time. This is the ratio found in the gas giant planets, such as Jupiter. However, other astronomical bodies are found to have different ratios of deuterium to hydrogen-1. This is thought to be a result of natural isotope separation processes that occur from solar heating

neg: Deuterium of ices in comets. Like the water cycle in Earth's weather, such heating processes may enrich deuterium with respect to protium. The analysis of deuterium/protium ratios in comets found results very similar to the mean ratio in Earth's oceans (156 atoms of deuterium per million hydrogens). This reinforces theories that much of Earth's ocean water is of cometary origin. The deuterium/protium ratio of the comet 67P/Churyumov-Gerasimenko, as measured by the Rosetta space probe, is about three times that of earth water. This figure is the highest yet measured in a comet. Deuterium/protium ratios thus continue to be an active topic

neg: Arthur Eddington expanding state, and most of his cosmological investigations focused on the constant's significance and characteristics. In "The Mathematical Theory of Relativity," Eddington interpreted the cosmological constant to mean that the universe is "self-gauging". During the 1920s until his death, Eddington increasingly concentrated on what he called "fundamental theory" which was intended to be a unification of quantum theory, relativity, cosmology, and gravitation. At first he progressed along "traditional" lines, but turned increasingly to an almost numerological analysis of the dimensionless ratios of fundamental constants. His basic approach was to combine several fundamental constants in order to produce a dimensionless number.

neg: Vienna Standard Mean Ocean Water use today. The isotopic composition of VSMOW water is specified as ratios of the molar abundance of the rare isotope in question divided by that of its most common isotope and is expressed as parts per million (ppm). For instance O (the most common isotope of oxygen with eight protons and eight neutrons) is roughly 2632 times more prevalent in sea water than is O (with an additional neutron). The isotopic ratios of VSMOW water are defined as follows: It should be noted that every molecule of water has 2 hydrogen atoms, so if one considers 3210 (half of 6420)

neg: Susan Alexjander their musical properties. In one of her earliest collaborations, with biologist David W. Deamer from the University of California, Alexjander created music based on movements of the atoms and molecules that make up human DNA. An infrared spectrophotometer was used to measure the wavelength of infrared light absorbed by sections of DNA and to identify frequencies for each DNA molecule. The ratios of the light frequencies were then converted into perceptible ratios of sound frequencies, often involving microtonal changes, to create "strange, beautiful music". The resulting album "Sequencia", a pioneering experiment in sound creation, was recorded on Earth Day, 1990.

neg: Atom lower energy state that has an energy difference matching the energy of the interacting photon. The emitted photon and the interacting photon then move off in parallel and with matching phases. That is, the wave patterns of the two photons are synchronized. This physical property is used to make lasers, which can emit a coherent beam of light energy in a narrow frequency band. Valency is the combining power of an element. It is equal to number of hydrogen atoms that atom can combine or displace in forming compounds. The outermost electron shell of an atom in its uncombined state

neg: John C. Goodman other factors, we would never expect the effort-benefit ratios of two opposing groups to be the same. Furthermore, Goodman and Porter discovered that small differences in political prices lead to large welfare losses for society as a whole—much larger, for example, than what we would ordinarily expect to find in the private sector. That leads to: Goodman’s Theorem: Since the conditions for optimality will almost never hold in any political system, optimal government is in principle impossible. If the political price milk producers are willing to pay is greater than the political price offered by the consumers of milk, we

neg: Helium-3 is less than that for assumptions of solar disk composition as obtained from meteorite and lunar samples, with terrestrial materials generally containing lower He/He ratios due to ingrowth of He from radioactive decay. He has a cosmological ratio of 300 atoms per million atoms of He (at. ppm), leading to the assumption that the original ratio of these primordial gases in the mantle was around 200-300 ppm when Earth was formed. A lot of He was generated by alpha-particle decay of uranium and thorium, and now the mantle has only around 7% primordial helium, lowering the total He/He ratio to

neg: Martian meteorite (stony) meteorites: "shergottites" (169), "nakhlites" (20), "chassignites" (3), and ones otherwise (15) (containing the orthopyroxenite (OPX) Allan Hills 84001, as well as 10 basaltic breccia meteorites). Consequently, Martian meteorites as a whole are sometimes referred to as the "SNC group". They have isotope ratios that are said to be consistent with each other and inconsistent with the Earth. The names derive from the location of where the first meteorite of their type was discovered. Roughly three-quarters of all Martian meteorites can be classified as shergottites. They are named after the Shergotty meteorite, which fell at Sherghati, India in 1865. Shergottites

neg: Boride at the other. The generally accepted definition is that if the ratio of boron atoms to metal atoms is 4:1 or more if the compound is boron rich, if it is less, then it is metal rich. The main group metals, lanthanides and actinides form a wide variety of boron-rich borides, with metal:boron ratios up to YB. The properties of this group vary from one compound to the next, and include examples of compounds that are semi conductors, superconductors, diamagnetic, paramagnetic, ferromagnetic or anti-ferromagnetic. They are mostly stable and refractory. Some metallic dodecaborides contain boron icosahedra, others (for example yttrium,

neg: Atomism combine. In both Jaina and Vaisesika atomism, atoms first combine in pairs (dyads), and then group into trios of pairs (triads), which are the smallest visible units of matter. The Buddhist atomists had very qualitative, Aristotelian-style atomic theory. According to ancient Buddhist atomism, which probably began developing before the 4th century BCE, there are four kinds of atoms, corresponding to the standard elements. Each of these elements has a specific property, such as solidity or motion, and performs a specific function in mixtures, such as providing support or causing growth. Like the Hindu Jains, the Buddhists were able to integrate

neg: Helium dimer this helium atoms are excited, and then combine to yield the dihelium ion. The He goes on to react with N in the air to make N. These ions react with a sample surface to make positive ions that are used in mass spectroscopy. The plasma containing the helium dimer can be as low as 30 °C in temperature, and this reduces heat damage to samples. He has been shown to form van der Waals compounds with other atoms forming bigger clusters such as MgHe and CaHe. The helium-4 trimer (He), a cluster of three helium atoms, is predicted to

neg: Chalcogen particle accelerators. Even when it is produced, only a small number of atoms at a time are synthesized. Chalcophile elements are those that remain on or close to the surface because they combine readily with chalcogens other than oxygen, forming compounds which do not sink into the core. Chalcophile ("chalcogen-loving") elements in this context are those metals and heavier nonmetals that have a low affinity for oxygen and prefer to bond with the heavier chalcogen sulfur as sulfides. Because sulfide minerals are much denser than the silicate minerals formed by lithophile elements, chalcophile elements separated below the lithophiles at the

neg: Argon compounds form van der Waals molecules. These can be made by expanding argon under high pressure mixed with the atoms of another element. The expansion happens through a tiny hole into a vacuum, and results in cooling to temperatures a few degrees above absolute zero. At higher temperatures the atoms will be too energetic to stay together by way of the weak London dispersion forces. The atoms that are to combine with argon can be produced by evaporation with a laser or alternatively by an electric discharge. The known molecules include AgAr, AgAr, NaAr, KAr, MgAr, CaAr, SrAr, ZnAr, CdAr, HgAr,

neg: Volumetric heat capacity above varies more widely, from about 1.2 MJ/m³K (for example bismuth) to 3.5 MJ/m³K (for example iron), but this is mostly due to differences in the physical size of atoms. See a discussion in atom. Atoms vary greatly in density, with the heaviest often being more dense, and thus are closer to taking up the same average volume in solids than their mass alone would predict. If all atoms "were" the same size, molar and volumetric heat capacity would be proportional and differ by only a single constant reflecting ratios of the atomic-molar-volume of materials (their atomic density). An additional

neg: Boron in the molecule. For example, in diborane BH, the boron oxidation state is +3, but in decaborane BH, it is / or +1.4. In these compounds the oxidation state of boron is often not a whole number. The boron nitrides are notable for the variety of structures that they adopt. They exhibit structures analogous to various allotropes of carbon, including graphite, diamond, and nanotubes. In the diamond-like structure, called cubic boron nitride (tradename Borazon), boron atoms exist in the tetrahedral structure of carbons atoms in diamond, but one in every four B-N bonds can be viewed as a coordinate covalent

neg: Plumbogummite to 17 Å, with Z=3. Various reported values of "a" and "c"are: Mills "et al." investigated a gallium-rich sample of plumbogummite from Tsumeb, Namibia, and found larger cell parameters, with a = 7.0752 Å and c = 16.818 Å. The basic structural units of plumbogummite are PO tetrahedra, with phosphorus atoms (P) at the center and oxygen atoms (O) at the corners, together with AlO octahedra, aluminium atoms (Al) at the center and oxygen atoms at the corners. The tetrahedra and octahedra combine by sharing corners, to form composite layers. Lead atoms (Pb) occupy sites between the layers. Plumbogummite is

neg: Network covalent bonding Network covalent bonding A network solid or covalent network solid is a chemical compound (or element) in which the atoms are bonded by covalent bonds in a continuous network extending throughout the material. In a network solid there are no individual molecules, and the entire crystal or amorphous solid may be considered a macromolecule. Formulas for network solids, like those for ionic compounds, are simple ratios of the component atoms represented by a formula unit. Examples of network solids include diamond with a continuous network of carbon atoms and silicon dioxide or quartz with a continuous three-dimensional network of SiO

neg: Monoisotopic mass general chemistry. Monoisotopic mass is typically expressed in unified atomic mass units (u), also called daltons (Da). The mass spectral peak representing the monoisotopic mass is not always the most abundant isotopic peak in a spectrum despite it containing the most abundant isotope for each atom. This is because as the number of atoms in a molecule increases, the probability that the entire molecule contains at least one heavy isotope atom also increases. For example, if there are 100 carbon atoms in a molecule each of which has an approximately 1% chance of being a heavy isotope the whole molecule

neg: Protein Structure Evaluation Suite & Server different structure parameters for the protein (as a whole), for different members of the structure ensemble, for specific residues and for specific atoms. Different shades of red indicate serious problems, different shades of yellow or amber indicate potential problems and different shades of green indicate that the protein model or its residues/atoms are free of problems. Each color is also assigned a number (ranging from 0 to 9 -- with 0 being bad and 9 being excellent) so that the structure quality assessment is more quantifiable. PROSESS’s quality indices and quality color scales have been designed specifically to help non-structural

neg: Titanate nanosheet appropriate solvent, creating single-layer colloidal suspensions. Solvents must have an interaction energy with the layers that is greater than the interaction energy between two layers. "In situ" X-Ray diffraction data indicates that TiNSs can be treated as macromolecules with a sufficient amount of solvent in between layers so that they behave as individual sheets. Unilamellar TiNSs have a number of unique properties, and are said to combine those of conventional titanate and titania. Structurally, they are infinite ultrathin (~0.75 nm) 2D sheets with a high density of negative surface charges originating from the oxygen atoms at the corners of the

neg: Locations of Half-Life pre-World War II neoclassicism, to post-war revival of classical designs, Soviet modernism, and post-Soviet contemporary designs, as well as Combine structures. The playable area of the city is quite large, including a railway station, a dilapidated canal system, underground road tunnels, multiple communal living quarters and crowded, tightly-packed tenement buildings. The whole city seems to be in an advanced state of urban decay, with abandoned structures and graffiti rampant throughout the city. It contains a large number of signs written in Cyrillic. The city is policed by the Combine Civil Protection, who patrol the streets and suppress dissent with extreme

neg: Hemoglobin 16000 ("n" = number of iron atoms per hemoglobin, now known to be 4), the first determination of a protein's molecular mass. This "hasty conclusion" drew a lot of ridicule at the time from scientists who could not believe that any molecule could be that big. Gilbert Smithson Adair confirmed Engelhard's results in 1925 by measuring the osmotic pressure of hemoglobin solutions. The oxygen-carrying property of hemoglobin was discovered by Hünefeld in 1840. In 1851, German physiologist Otto Funke published a series of articles in which he described growing hemoglobin crystals by successively diluting red blood cells with a solvent

neg: Tau (particle) branching ratio of the dominant hadronic tau decays are: In total, the tau lepton will decay hadronically approximately 64.79% of the time. Since the tauonic lepton number is conserved in weak decays, a tau neutrino is always created when a tau decays. The branching ratio of the common purely leptonic tau decays are: The similarity of values of the two branching ratios is a consequence of lepton universality. The tau lepton is predicted to form exotic atoms like other charged subatomic particles. One of such, called tauonium by the analogy to muonium, consists of an antitauon and an electron: .

neg: Infrared spectroscopy of the whole molecule rather than vibrations within it. These figures do not represent the "recoil" of the C atoms, which, though necessarily present to balance the overall movements of the molecule, are much smaller than the movements of the lighter H atoms. The simplest and most important or "fundamental" IR bands arise from the excitations of normal modes, the simplest distortions of the molecule, from the ground state with vibrational quantum number v = 0 to the first excited state with vibrational quantum number v = 1. In some cases, overtone bands are observed. An overtone band arises from

neg: Rydberg polaron Rydberg polaron A Rydberg polaron is an exotic state of matter, created at low temperatures, in which a very large atom contains other ordinary atoms in the space between the nucleus and the electrons. For the formation of this atom, scientists had to combine two fields of atomic physics: Bose-Einstein condensates and Rydberg atoms. Rydberg atoms are formed by exciting a single atom into a high-energy state, in which the electron is very far from the nucleus. Bose-Einstein condensates are a state of matter that is produced at temperatures close to absolute zero. Polarons are induced by using a laser

neg: Theory of everything called a theory of everything. In the late 1920s, the new quantum mechanics showed that the chemical bonds between atoms were examples of (quantum) electrical forces, justifying Dirac's boast that "the underlying physical laws necessary for the mathematical theory of a large part of physics and the whole of chemistry are thus completely known". After 1915, when Albert Einstein published the theory of gravity (general relativity), the search for a unified field theory combining gravity with electromagnetism began with a renewed interest. In Einstein's day, the strong and the weak forces had not yet been discovered, yet, he found the

neg: Big Bang nucleosynthesis combine quickly into one helium-4 nucleus. This produces one helium for every 12 hydrogens, resulting in a universe that is a little over 8% helium by number of atoms, and 25% helium by mass. One analogy is to think of helium-4 as ash, and the amount of ash that one forms when one completely burns a piece of wood is insensitive to how one burns it. The resort to the BBN theory of the helium-4 abundance is necessary as there is far more helium-4 in the universe than can be explained by stellar nucleosynthesis. In addition, it provides an important

neg: Prout's hypothesis minus the mass of the nuclear binding energy, the mass defect. According to the whole number rule proposed by Francis Aston, the mass of an isotope is roughly, but not exactly, its mass number "A" = "Z" + "N" times an atomic mass unit (u), plus or minus binding energy discrepancy – atomic mass unit being the modern approximation for "mass of a proton, neutron, or hydrogen atom". For example iron-56 atoms (which have among the highest binding-energies) weigh only about 99.1% as much as 56 hydrogen atoms. The missing 0.9% of mass represents the energy lost when the nucleus

neg: Harmony the evolution of harmonic practice and language itself, in Western art music, is and was facilitated by this process of prior composition, which permitted the study and analysis by theorists and composers of individual pre-constructed works in which pitches (and to some extent rhythms) remained unchanged regardless of the nature of the performance. Some traditions of Western music performance, composition, and theory have specific rules of harmony. These rules are often described as based on natural properties such as Pythagorean tuning's law whole number ratios ("harmoniousness" being inherent in the ratios either perceptually or in themselves) or harmonics and resonances

neg: Oxygen balance that are excess or deficient for 100 grams of a compound. where "X" = number of atoms of carbon, "Y" = number of atoms of hydrogen, "Z" = number of atoms of oxygen, and "M" = number of atoms of metal (metallic oxide produced). In the case of TNT (CH(NO)CH), Molecular weight = 227.1 "X" = 7 (number of carbon atoms) "Y" = 5 (number of hydrogen atoms) "Z" = 6 (number of oxygen atoms) Therefore, Because sensitivity, brisance, and strength are properties resulting from a complex explosive chemical reaction, a simple relationship such as oxygen balance cannot be depended

neg: Chemistry: A Volatile History two completely different compounds. Wöhler and von Liebig had inadvertently discovered isomerism: the same number of atoms of the same elements "combining in different ways" to make "different" compounds. In time, this would explain how just 92 elements could make the vast array of compounds we know today. Chemists started to realise that understanding the arrangement of atoms within compounds was crucial if they wished to design new compounds, and the first step in this direction was taken by studying carbon. In 1796 Smithson Tennant was experimenting on diamonds when he decided to burn one. Using only sunlight and a