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Livestock production systems can be defined based on feed source, as grassland-based, mixed, and landless. , 30% of Earth's ice- and water-free area was used for producing livestock, with the sector employing approximately 1.3 billion people. Between the 1960s and the 2000s, there was a significant increase in livestoc...
Grassland based livestock production relies upon plant material such as shrubland, rangeland, and pastures for feeding ruminant animals. Outside nutrient inputs may be used, however manure is returned directly to the grassland as a major nutrient source. This system is particularly important in areas where crop product...
Production practices. Tillage is the practice of breaking up the soil with tools such as the plow or harrow to prepare for planting, for nutrient incorporation, or for pest control. Tillage varies in intensity from conventional to no-till. It can improve productivity by warming the soil, incorporating fertilizer and co...
Water management is needed where rainfall is insufficient or variable, which occurs to some degree in most regions of the world. Some farmers use irrigation to supplement rainfall. In other areas such as the Great Plains in the U.S. and Canada, farmers use a fallow year to conserve soil moisture for the following year....
Payment for ecosystem services is a method of providing additional incentives to encourage farmers to conserve some aspects of the environment. Measures might include paying for reforestation upstream of a city, to improve the supply of fresh water. Agricultural automation. Different definitions exist for agricultural ...
The technological evolution in agriculture has involved a progressive move from manual tools to animal traction, to motorized mechanization, to digital equipment and finally, to robotics with artificial intelligence (AI). Motorized mechanization using engine power automates the performance of agricultural operations su...
Automation technologies are increasingly used for managing livestock, though evidence on adoption is lacking. Global automatic milking system sales have increased over recent years, but adoption is likely mostly in Northern Europe, and likely almost absent in low- and middle-income countries. Automated feeding machines...
Effects of climate change on yields. Climate change and agriculture are interrelated on a global scale. Climate change affects agriculture through changes in average temperatures, rainfall, and weather extremes (like storms and heat waves); changes in pests and diseases; changes in atmospheric carbon dioxide and ground...
Crop alteration and biotechnology. Plant breeding. Crop alteration has been practiced by humankind for thousands of years, since the beginning of civilization. Altering crops through breeding practices changes the genetic make-up of a plant to develop crops with more beneficial characteristics for humans, for example, ...
The Green Revolution popularized the use of conventional hybridization to sharply increase yield by creating "high-yielding varieties". For example, average yields of corn (maize) in the US have increased from around 2.5 tons per hectare (t/ha) (40 bushels per acre) in 1900 to about 9.4 t/ha (150 bushels per acre) in 2...
Agricultural innovation developed for the specific agroecological conditions of one region is not easily transferred and used in another region with different agroecological conditions. Instead, the innovation would have to be adapted to the specific conditions of that other region and respect its biodiversity and envi...
Herbicide-resistant seeds have a gene implanted into their genome that allows the plants to tolerate exposure to herbicides, including glyphosate. These seeds allow the farmer to grow a crop that can be sprayed with herbicides to control weeds without harming the resistant crop. Herbicide-tolerant crops are used by far...
Environmental impact. Effects and costs. Agriculture is both a cause of and sensitive to environmental degradation, such as biodiversity loss, desertification, soil degradation and climate change, which cause decreases in crop yield. Agriculture is one of the most important drivers of environmental pressures, particula...
Agriculture seeks to increase yield and to reduce costs, often employing measures that cut biodiversity to very low levels. Yield increases with inputs such as fertilizers and removal of pathogens, predators, and competitors (such as weeds). Costs decrease with increasing scale of farm units, such as making fields larg...
Land and water issues. Land transformation, the use of land to yield goods and services, is the most substantial way humans alter the Earth's ecosystems, and is the driving force causing biodiversity loss. Estimates of the amount of land transformed by humans vary from 39 to 50%. It is estimated that 24% of land global...
Eutrophication, excessive nutrient enrichment in aquatic ecosystems resulting in algal blooms and anoxia, leads to fish kills, loss of biodiversity, and renders water unfit for drinking and other industrial uses. Excessive fertilization and manure application to cropland, as well as high livestock stocking densities ca...
Pesticides. Pesticide use has increased since 1950 to 2.5 million short tons annually worldwide, yet crop loss from pests has remained relatively constant. The World Health Organization estimated in 1992 that three million pesticide poisonings occur annually, causing 220,000 deaths. Pesticides select for pesticide resi...
Contribution to climate change. Agriculture contributes towards climate change through greenhouse gas emissions and by the conversion of non-agricultural land such as forests into agricultural land. The agriculture, forestry and land use sector contribute between 13% and 21% of global greenhouse gas emissions. Emission...
Climate change put significant part of crops in danger already at 1.5 degrees of warming. While in North Anerica, Europe and central Asia the share of endangered crops is relatively little at this level of warming, in the Middle east and North Africa region for example, close to 50% of cropland is in danger. With furth...
Technological advancements help provide farmers with tools and resources to make farming more sustainable. Technology permits innovations like conservation tillage, a farming process which helps prevent land loss to erosion, reduces water pollution, and enhances carbon sequestration. Agricultural automation can help ad...
The food demand of Earth's projected population, with current climate change predictions, could be satisfied by improvement of agricultural methods, expansion of agricultural areas, and a sustainability-oriented consumer mindset. Energy dependence. Since the 1940s, agricultural productivity has increased dramatically, ...
Indirect consumption includes the manufacture of fertilizers, pesticides, and farm machinery. In particular, the production of nitrogen fertilizer can account for over half of agricultural energy usage. Together, direct and indirect consumption by US farms accounts for about 2% of the nation's energy use. Direct and in...
The total amount of plastics used in agriculture is difficult to quantify. A 2012 study reported that almost 6.5 million tonnes per year were consumed globally while a later study estimated that global demand in 2015 was between 7.3 million and 9 million tonnes. Widespread use of plastic mulch and lack of systematic co...
Disciplines. Agricultural economics. Agricultural economics is economics as it relates to the "production, distribution and consumption of [agricultural] goods and services". Combining agricultural production with general theories of marketing and business as a discipline of study began in the late 1800s, and grew sign...
National government policies, such as taxation, subsidies, tariffs and others, can significantly change the economic marketplace for agricultural products. Since at least the 1960s, a combination of trade restrictions, exchange rate policies and subsidies have affected farmers in both the developing and the developed w...
Agricultural science. Agricultural science is a broad multidisciplinary field of biology that encompasses the parts of exact, natural, economic and social sciences used in the practice and understanding of agriculture. It covers topics such as agronomy, plant breeding and genetics, plant pathology, crop modeling, soil ...
Policy. Agricultural policy is the set of government decisions and actions relating to domestic agriculture and imports of foreign agricultural products. Governments usually implement agricultural policies with the goal of achieving a specific outcome in the domestic agricultural product markets. Some overarching theme...
A 2021 report finds that globally, support to agricultural producers accounts for almost US$540 billion a year. This amounts to 15 percent of total agricultural production value, and is heavily biased towards measures that are leading to inefficiency, as well as are unequally distributed and harmful for the environment...
Aldous Huxley Aldous Leonard Huxley ( ; 26 July 1894 – 22 November 1963) was an English writer and philosopher. His bibliography spans nearly 50 books, including non-fiction works, as well as essays, narratives, and poems. Born into the prominent Huxley family, he graduated from Balliol College, Oxford, with a degree i...
Early life. Huxley was born in Godalming, Surrey, England, on 26 July 1894. He was the third son of the writer and schoolmaster Leonard Huxley, who edited "The Cornhill Magazine", and his first wife, Julia Arnold, who founded Prior's Field School. Julia was the niece of poet and critic Matthew Arnold and the sister of ...
Huxley's education began in his father's well-equipped botanical laboratory, after which he enrolled at Hillside School near Godalming. He was taught there by his own mother for several years until she became terminally ill. After Hillside he went on to Eton College. His mother died in 1908, when he was 14 (his father ...
Huxley also worked for a time during the 1920s at Brunner and Mond, an advanced chemical plant in Billingham in County Durham, northeast England. According to an introduction to his science fiction novel "Brave New World" (1932), the experience he had there of "an ordered universe in a world of planless incoherence" wa...
Works of this period included novels about the dehumanising aspects of scientific progress, (his magnum opus "Brave New World"), and on pacifist themes ("Eyeless in Gaza"). In "Brave New World", set in a dystopian London, Huxley portrays a society operating on the principles of mass production and Pavlovian conditionin...
Heard introduced Huxley to Vedanta (Upanishad-centered philosophy), meditation, and vegetarianism through the principle of ahimsa. In 1938, Huxley befriended Jiddu Krishnamurti, whose teachings he greatly admired. Huxley and Krishnamurti entered into an enduring exchange (sometimes edging on debate) over many years, wi...
During this period, Huxley earned a substantial income as a Hollywood screenwriter; Christopher Isherwood, in his autobiography "My Guru and His Disciple", states that Huxley earned more than $3,000 per week (approximately $50,000 in 2020 dollars) as a screenwriter, and that he used much of it to transport Jewish and l...
Huxley wrote an introduction to the posthumous publication of J. D. Unwin's 1940 book "Hopousia or The Sexual and Economic Foundations of a New Society". On 21 October 1949, Huxley wrote to George Orwell, author of "Nineteen Eighty-Four", congratulating him on "how fine and how profoundly important the book is". In his...
Robert S. de Ropp (scientist, humanitarian, and author), who had spent time with Huxley in England in the 1930s, connected with him again in the U.S. in the early 1960s and wrote that "the enormous intellect, the beautifully modulated voice, the gentle objectivity, all were unchanged. He was one of the most highly civi...
Huxley's engagement with Eastern wisdom traditions was entirely compatible with a strong appreciation of modern science. Biographer Milton Birnbaum wrote that Huxley "ended by embracing both science and Eastern religion". In his last book, "Literature and Science", Huxley wrote that "The ethical and philosophical impli...
In the 1920s, Huxley was skeptical of religion, "Earlier in his career he had rejected mysticism, often poking fun at it in his novels [...]" Gerald Heard became an influential friend of Huxley, and since the mid-1920s had been exploring Vedanta, as a way of understanding individual human life and the individual's rela...
In the late 1930s, Huxley and Heard immigrated to the United States, and beginning in 1939 and continuing until his death in 1963, Huxley had an extensive association with the Vedanta Society of Southern California, founded and headed by Swami Prabhavananda. Together with Gerald Heard, Christopher Isherwood and other f...
In 1944, Huxley wrote the introduction to the "Bhagavad Gita – The Song of God", translated by Swami Prabhavananda and Christopher Isherwood, which was published by the Vedanta Society of Southern California. As an advocate of the perennial philosophy, Huxley was drawn to the "Gita", as he explained in the Introduction...
Huxley also occasionally lectured at the Hollywood and Santa Barbara Vedanta temples. Two of those lectures have been released on CD: "Knowledge and Understanding" and "Who Are We?" from 1955. Many of Huxley's contemporaries and critics were disappointed by Huxley's turn to mysticism; Isherwood describes in his diary h...
Huxley wrote that "The mystical experience is doubly valuable; it is valuable because it gives the experiencer a better understanding of himself and the world and because it may help him to lead a less self-centered and more creative life." Having tried LSD in the 1950s, he became an advisor to Timothy Leary and Richar...
It was, and is, widely believed that Huxley was nearly blind since the illness in his teens, despite the partial recovery that had enabled him to study at Oxford. For example, some ten years after publication of "The Art of Seeing", in 1952, Bennett Cerf was present when Huxley spoke at a Hollywood banquet, wearing no ...
American popular science author Steven Johnson, in his book "Mind Wide Open", quotes Huxley about his difficulties with visual encoding: Personal life. Huxley married on 10 July 1919 Maria Nys (10 September 1899 – 12 February 1955), a Belgian epidemiologist from Bellem, a village near Aalter, he met at Garsington, Oxf...
Huxley was a close friend of Jiddu Krishnamurti and Rosalind Rajagopal, and was involved in the creation of the Happy Valley School, now Besant Hill School, of Happy Valley, in Ojai, California. The most substantial collection of Huxley's few remaining papers, following the destruction of most in the 1961 Bel Air Fire,...
At home on his deathbed, unable to speak owing to cancer that had metastasized, Huxley made a written request to his wife Laura for "LSD, 100 μg, intramuscular." According to her account of his death in "This Timeless Moment", she obliged with an injection at 11:20 a.m. and a second dose an hour later; Huxley died aged...
Huxley's memorial service took place in London in December 1963; it was led by his elder brother Julian. On 27 October 1971, his ashes were interred in the family grave at the Watts Cemetery, home of the Watts Mortuary Chapel in Compton, Guildford, Surrey, England. Huxley had been a long-time friend of Russian composer...
Aberdeen (disambiguation) Aberdeen is a city in Scotland. Aberdeen may also refer to:
Algae Algae ( , ; : alga ) is an informal term for any organisms of a large and diverse group of photosynthetic eukaryotes, which include species from multiple distinct clades. Such organisms range from unicellular microalgae such as "Chlorella", "Prototheca" and the diatoms, to multicellular macroalgae such as the gia...
Algae lack the various structures that characterize plants (which evolved from freshwater green algae), such as the phyllids (leaf-like structures) and rhizoids of bryophytes (non-vascular plants), and the roots, leaves and other xylemic/phloemic organs found in tracheophytes (vascular plants). Most algae are autotroph...
Because of the wide range of types of algae, there is a correspondingly wide range of industrial and traditional applications in human society. Traditional seaweed farming practices have existed for thousands of years and have strong traditions in East Asian food cultures. More modern algaculture applications extend th...
The Ancient Greek word for 'seaweed' was (), which could mean either the seaweed (probably red algae) or a red dye derived from it. The Latinization, , meant primarily the cosmetic rouge. The etymology is uncertain, but a strong candidate has long been some word related to the Biblical (), 'paint' (if not that word its...
The algae contain chloroplasts that are similar in structure to cyanobacteria. Chloroplasts contain circular DNA like that in cyanobacteria and are interpreted as representing reduced endosymbiotic cyanobacteria. However, the exact origin of the chloroplasts is different among separate lineages of algae, reflecting the...
In 1768, Samuel Gottlieb Gmelin (1744–1774) published the "Historia Fucorum", the first work dedicated to marine algae and the first book on marine biology to use the then new binomial nomenclature of Linnaeus. It included elaborate illustrations of seaweed and marine algae on folded leaves. W. H. Harvey (1811–1866) an...
Although used as a taxonomic category in some pre-Darwinian classifications, e.g., Linnaeus (1753), de Jussieu (1789), Lamouroux (1813), Harvey (1836), Horaninow (1843), Agassiz (1859), Wilson & Cassin (1864), in further classifications, the "algae" are seen as an artificial, polyphyletic group. Throughout the 20th...
Some parasitic algae (e.g., the green algae "Prototheca" and "Helicosporidium", parasites of metazoans, or "Cephaleuros", parasites of plants) were originally classified as fungi, sporozoans, or protistans of "incertae sedis", while others (e.g., the green algae "Phyllosiphon" and "Rhodochytrium", parasites of plants, ...
Recent genomic and phylogenomic approaches have significantly clarified plastid genome evolution, the horizontal movement of endosymbiont genes to the "host" nuclear genome, and plastid spread throughout the eukaryotic tree of life. Relationship to land plants. Fossils of isolated spores suggest land plants may have be...
Most of the simpler algae are unicellular flagellates or amoeboids, but colonial and nonmotile forms have developed independently among several of the groups. Some of the more common organizational levels, more than one of which may occur in the lifecycle of a species, are In three lines, even higher levels of organiza...
Physiology. Many algae, particularly species of the Characeae, have served as model experimental organisms to understand the mechanisms of the water permeability of membranes, osmoregulation, salt tolerance, cytoplasmic streaming, and the generation of action potentials. Plant hormones are found not only in higher plan...
Trentepohlia is an example of a common green alga genus worldwide that can grow on its own or be lichenised. Lichen thus share some of the habitat and often similar appearance with specialized species of algae ("aerophytes") growing on exposed surfaces such as tree trunks and rocks and sometimes discoloring them. Coral...
Sea sponges. Endosymbiontic green algae live close to the surface of some sponges, for example, breadcrumb sponges ("Halichondria panicea"). The alga is thus protected from predators; the sponge is provided with oxygen and sugars which can account for 50 to 80% of sponge growth in some species. Life cycle. Rhodophyta, ...
Numbers. The "Algal Collection of the US National Herbarium" (located in the National Museum of Natural History) consists of approximately 320,500 dried specimens, which, although not exhaustive (no exhaustive collection exists), gives an idea of the order of magnitude of the number of algal species (that number remain...
The most recent estimate suggests 72,500 algal species worldwide. Distribution. The distribution of algal species has been fairly well studied since the founding of phytogeography in the mid-19th century. Algae spread mainly by the dispersal of spores analogously to the dispersal of cryptogamic plants by spores. Spores...
To some degree, the distribution of algae is subject to floristic discontinuities caused by geographical features, such as Antarctica, long distances of ocean or general land masses. It is, therefore, possible to identify species occurring by locality, such as "Pacific algae" or "North Sea algae". When they occur out o...
The various sorts of algae play significant roles in aquatic ecology. Microscopic forms that live suspended in the water column (phytoplankton) provide the food base for most marine food chains. In very high densities (algal blooms), these algae may discolor the water and outcompete, poison, or asphyxiate other life fo...
Cultural associations. In classical Chinese, the word is used both for "algae" and (in the modest tradition of the imperial scholars) for "literary talent". The third island in Kunming Lake beside the Summer Palace in Beijing is known as the Zaojian Tang Dao (藻鑒堂島), which thus simultaneously means "Island of the Algae-...
Energy source. To be competitive and independent from fluctuating support from (local) policy on the long run, biofuels should equal or beat the cost level of fossil fuels. Here, algae-based fuels hold great promise, directly related to the potential to produce more biomass per unit area in a year than any other form o...
Three forms of algae used as food: The oils from some algae have high levels of unsaturated fatty acids. Some varieties of algae favored by vegetarianism and veganism contain the long-chain, essential omega-3 fatty acids, docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). Fish oil contains the omega-3 fatty ac...
Polymers. Various polymers can be created from algae, which can be especially useful in the creation of bioplastics. These include hybrid plastics, cellulose-based plastics, poly-lactic acid, and bio-polyethylene. Several companies have begun to produce algae polymers commercially, including for use in flip-flops and i...
Analysis of variance Analysis of variance (ANOVA) is a family of statistical methods used to compare the means of two or more groups by analyzing variance. Specifically, ANOVA compares the amount of variation "between" the group means to the amount of variation "within" each group. If the between-group variation is sub...
from reaction times (the "personal equation") and had developed methods of reducing the errors. The experimental methods used in the study of the personal equation were later accepted by the emerging field of psychology which developed strong (full factorial) experimental methods to which randomization and blinding wer...
Randomization models were developed by several researchers. The first was published in Polish by Jerzy Neyman in 1923. Example. The analysis of variance can be used to describe otherwise complex relations among variables. A dog show provides an example. A dog show is not a random sampling of the breed: it is typically ...
In the illustrations to the right, groups are identified as "X"1, "X"2, etc. In the first illustration, the dogs are divided according to the product (interaction) of two binary groupings: young vs old, and short-haired vs long-haired (e.g., group 1 is young, short-haired dogs, group 2 is young, long-haired dogs, etc.)...
An attempt to explain weight by breed is likely to produce a very good fit. All Chihuahuas are light and all St Bernards are heavy. The difference in weights between Setters and Pointers does not justify separate breeds. The analysis of variance provides the formal tools to justify these intuitive judgments. A common u...
Random-effects models. Random-effects model (class II) is used when the treatments are not fixed. This occurs when the various factor levels are sampled from a larger population. Because the levels themselves are random variables, some assumptions and the method of contrasting the treatments (a multi-variable generaliz...
Defining fixed and random effects has proven elusive, with multiple competing definitions. Assumptions. The analysis of variance has been studied from several approaches, the most common of which uses a linear model that relates the response to the treatments and blocks. Note that the model is linear in parameters but ...
Unit-treatment additivity. In its simplest form, the assumption of unit-treatment additivity states that the observed response formula_3 from experimental unit formula_4 when receiving treatment formula_5 can be written as the sum of the unit's response formula_6 and the treatment-effect formula_7, that is formula_8 T...
Derived linear model. Kempthorne uses the randomization-distribution and the assumption of "unit treatment additivity" to produce a "derived linear model", very similar to the textbook model discussed previously. The test statistics of this derived linear model are closely approximated by the test statistics of an appr...
Statistical models for observational data. However, when applied to data from non-randomized experiments or observational studies, model-based analysis lacks the warrant of randomization. For observational data, the derivation of confidence intervals must use "subjective" models, as emphasized by Ronald Fisher and his ...
However, studies of processes that change variances rather than means (called dispersion effects) have been successfully conducted using ANOVA. There are "no" necessary assumptions for ANOVA in its full generality, but the "F"-test used for ANOVA hypothesis testing has assumptions and practical limitations which are o...
Characteristics. ANOVA is used in the analysis of comparative experiments, those in which only the difference in outcomes is of interest. The statistical significance of the experiment is determined by a ratio of two variances. This ratio is independent of several possible alterations to the experimental observations: ...
Partitioning of the sum of squares. ANOVA uses traditional standardized terminology. The definitional equation of sample variance is formula_12, where the divisor is called the degrees of freedom (DF), the summation is called the sum of squares (SS), the result is called the mean square (MS) and the squared terms are ...
formula_13 The number of degrees of freedom "DF" can be partitioned in a similar way: one of these components (that for error) specifies a chi-squared distribution which describes the associated sum of squares, while the same is true for "treatments" if there is no treatment effect. formula_14 The "F"-test. The "F"-tes...
There are two methods of concluding the ANOVA hypothesis test, both of which produce the same result: The ANOVA "F"-test is known to be nearly optimal in the sense of minimizing false negative errors for a fixed rate of false positive errors (i.e. maximizing power for a fixed significance level). For example, to test t...
For a single factor. The simplest experiment suitable for ANOVA analysis is the completely randomized experiment with a single factor. More complex experiments with a single factor involve constraints on randomization and include completely randomized blocks and Latin squares (and variants: Graeco-Latin squares, etc.)....
For multiple factors. ANOVA generalizes to the study of the effects of multiple factors. When the experiment includes observations at all combinations of levels of each factor, it is termed factorial. Factorial experiments are more efficient than a series of single factor experiments and the efficiency grows as the num...
Caution is advised when encountering interactions; Test interaction terms first and expand the analysis beyond ANOVA if interactions are found. Texts vary in their recommendations regarding the continuation of the ANOVA procedure after encountering an interaction. Interactions complicate the interpretation of experimen...
Associated analysis. Some analysis is required in support of the "design" of the experiment while other analysis is performed after changes in the factors are formally found to produce statistically significant changes in the responses. Because experimentation is iterative, the results of one experiment alter plans for...
Besides the power analysis, there are less formal methods for selecting the number of experimental units. These include graphical methods based on limiting the probability of false negative errors, graphical methods based on an expected variation increase (above the residuals) and methods based on achieving a desired c...
Model confirmation. Sometimes tests are conducted to determine whether the assumptions of ANOVA appear to be violated. Residuals are examined or analyzed to confirm homoscedasticity and gross normality. Residuals should have the appearance of (zero mean normal distribution) noise when plotted as a function of anything ...
Follow-up tests to identify which specific groups, variables, or factors have statistically different means include the Tukey's range test, and Duncan's new multiple range test. In turn, these tests are often followed with a Compact Letter Display (CLD) methodology in order to render the output of the mentioned tests m...
ANOVA is (in part) a test of statistical significance. The American Psychological Association (and many other organisations) holds the view that simply reporting statistical significance is insufficient and that reporting confidence bounds is preferred. Generalizations. ANOVA is considered to be a special case of linea...
The one-hot encoding function formula_37 is defined such that the formula_4-th entry of formula_39 is formula_40 The vector formula_36 is the concatenation of all of the above vectors for all formula_32. Thus, formula_43. In order to obtain a fully general formula_29-way interaction ANOVA we must also concatenate every...
Alkane In organic chemistry, an alkane, or paraffin (a historical trivial name that also has other meanings), is an acyclic saturated hydrocarbon. In other words, an alkane consists of hydrogen and carbon atoms arranged in a tree structure in which all the carbon–carbon bonds are single. Alkanes have the general chemic...
In an alkane, each carbon atom is sp3-hybridized with 4 sigma bonds (either C–C or C–H), and each hydrogen atom is joined to one of the carbon atoms (in a C–H bond). The longest series of linked carbon atoms in a molecule is known as its carbon skeleton or carbon backbone. The number of carbon atoms may be considered a...
The alkanes have two main commercial sources: petroleum (crude oil) and natural gas. An alkyl group is an alkane-based molecular fragment that bears one open valence for bonding. They are generally abbreviated with the symbol for any organyl group, R, although Alk is sometimes used to specifically symbolize an alkyl gr...
formula_1 The determinant of this matrix alternates between -1, 0 and 1 for successive members of the series. The adjacency matrix for the homologous series of (unbranched) monocyclic cycloalkanes can be written as: formula_2 where formula_3 is the number of carbon atoms (order of the matrix). The determinant of this m...
Branched alkanes are more thermodynamically stable than their linear (or less branched) isomers. For example, the highly branched 2,2,3,3-tetramethylbutane is about 1.9 kcal/mol more stable than its linear isomer, "n"-octane. Nomenclature. The IUPAC nomenclature (systematic way of naming compounds) for alkanes is based...
The first eight members of the series (in terms of number of carbon atoms) are named as follows: The first four names were derived from methanol, ether, propionic acid and butyric acid. Alkanes with five or more carbon atoms are named by adding the suffix -ane to the appropriate numerical multiplier prefix with elision...

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