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Paleogeography reconstruction of the Early Triassic world (left panel), showing that fishes and ichthyosaurs vacated the equator during the Smithian, with tetrapods exclusively occurring in the northern and southern middle to high latitudes…

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from article Ancient lethal hothouse

A scanning electron microscope image of the Early Triassic conodont Neospathodus, which is used for temperature reconstruction in this study.

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from article Stress and depression

Diagram of the hypothalamic-pituitary-adrenal axis. ACTH, adrenocorticotropin; CRH, corticotropin-releasing hormone.

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from article Phylogenetics: predicting rarity and endangerment

Phylogenetic tree of the family Hominidae [consisting of humans (Homo sapiens) and the great apes—orangutan (Pongo pygmaeus), common chimpanzee (Pan troglodytes), pygmy chimpanzee (Pan paniscus), and gorilla (Gorilla gorilla)], with branch lengths…

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from article Phylogenetics: predicting rarity and endangerment

(Top) Number of mammal species within various IUCN Red List categories. (Bottom) Percent of threatened (critically endangered + endangered + vulnerable) species within each major mammalian order; primates, including the great apes, contain the…

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from article Wood supply and demand

U.S. annual wood pulp production, 1900–2009. (Sources: Forest Service, Commerce Department, American Forest & Paper Association, International Woodfiber Report)

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from article Wood supply and demand

U.S. annual paper and paperboard consumption, and real gross domestic product (GDP), 1970–2009. [Sources: U.S. Bureau of Economic Analysis (GDP); American Forest & Paper Association (apparent consumption, including wet machine board and construction…

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from article Wood supply and demand

Annual U.S. consumption of paper and paperboard by principal category, 1970–2009. [Source: American Forest & Paper Association (excluding wet machine board and construction paper)]

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from article Wood supply and demand

U.S. solid wood and composite wood consumption as a percentage of domestic production.

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from article Wood supply and demand

U.S. timber growing stock net annual growth and removals, billions of cubic feet, 1986–2006.

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from article Wood supply and demand

U.S. real price indexes for delivered timber commodities, 1982–2009. [Source: Bureau of Labor Statistics, Producer Price Indexes (deflated using all-commodity producer price index)]

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from article Post-Paleozoic ecological complexity

Two contrasting relative abundance distributions from Ordovician and Pleistocene assemblages of skeletonized bottom-dwelling marine animals, representing early Paleozoic and late post-Paleozoic time intervals, respectively. Abundances are shown on a…

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from article Post-Paleozoic ecological complexity

(a) Simple and (b) complex model relative abundance distributions (RADs) are shown as the proportions of individuals belonging to each species in a community, with species ordered from most to least abundant. Distributions were calculated with the…

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from article Post-Paleozoic ecological complexity

(a) Percentages of complex RADs for fossil assemblages in the Paleozoic and post-Paleozoic are shown. All statistically significant RADs are summarized within successive geologic time periods as mean values (circles) and error bars indicating one…

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from article Bubble-rafting snails

(a) Live bubble-rafting violet snail (Janthina exigua) with float and egg capsules (labeled “e”) [photo courtesy of Denis Riek; www.roboastra.com]. (b) Live female wentletrap (Epifungium ulu) with egg mass (labeled “e”) and dwarf male (indicated by…

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from article Bubble-rafting snails

Evolutionary relationships of janthinids and epitoniids. (Left) Reduced evolutionary tree showing the results of a multigene DNA analysis of violet snails (top four species), wentletraps, and other putative benthic sister lineages. Violet snails are…

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from article Phthalates in western Aleutian Island seabirds

Map of islands from which samples have been collected (2009–2014).

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from article Oxytocin and autism

Oxytocin increases eye contact. (a, b) Gaze time spent on the face under oxytocin and placebo. (c, d) Gaze time spent on different regions of interest under oxytocin and placebo. (Reprinted with permission from E. Andari et al., Promoting social…

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from article Oxytocin and autism

Oxytocin improves social comprehension. (a) Computer ball game showing the amount of reciprocation of each partner toward the participant P (indicated by the tinted arrows). Gray arrows indicate a healthy subject's performance. (b) Number of balls…

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from article Oxytocin and autism

Time course of ball tosses during the computer ball game. Cumulative number of balls sent by participants (vertical axis) after each trial played by the good partner (horizontal axis). (Reprinted with permission from E. Andari et al., Promoting…

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from article Factors related to risk of autism

Rising prevalence rates of autism in the United States (1997–2008). PDD: pervasive developmental disorder. (Left panel: C. A. Boyle et al., Trends in the prevalence of developmental disabilities in US children, 1997–2008, Pediatrics, 127:1034–1042,…

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from article Pulsar navigation

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from article Pulsar navigation

Crab Nebula and pulsar in the x-ray band, imaged by NASA's Chandra X-ray Observatory. (NASA, CXC, SAO)

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from article Pulsar navigation

ARGOS satellite with the USA experiment.

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from article Effects of global warming on polar bears

Wrangel Island, Russia.

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from article Effects of global warming on polar bears

Number of bears recorded on Wrangel Island during ice-free seasons in 2004–2010.

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from article Effects of global warming on polar bears

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from article Effects of global warming on polar bears

Percentage of bears in various physical conditions observed on Wrangel Island during ice-free seasons in 2002–2010.

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from article Effects of global warming on polar bears

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from article Kale

Kale (Brassica oleracea var. acephala). (Photo courtesy of Howard F. Schwartz, Colorado State University)

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from article Olive

Olive tree (Olea europaea). (Photo courtesy of Piero Amorati, IC Croce, Casalecchio di Reno; www.Bugwood.org)

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from article Olive

Close-up view of an unripe green olive. (Photo courtesy of Piero Amorati, IC Croce, Casalecchio di Reno; www.Bugwood.org)

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from article Tropical forest

Tropical rainforest on Brunei. (Credit: Rodney Keenan)

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from article Tropical forest

Monsoon tropical forest in Queensland, Australia. (Credit: Rodney Keenan)

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from article Tropical forest

Tropical savanna forest in Northern Territory, Australia. (Credit: Rodney Keenan)

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from article Tropical forest

Natural forest areas (in thousands of hectares; 1 hectare = 2.47 acres) in various climatic domains (boreal/polar, temperate, subtropical, and tropical) from 1990 to 2015. The data are derived from the Global Forest Resources Assessment 2015 by the…

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from article Tropical forest

Tropical forest climatic zones around the world. Tropical rainforests are indicated by dark blue; tropical monsoon forests are indicated by a medium shade of blue; tropical savanna forests are indicated by light blue. (Credit: Based on data compiled…

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from article Aircraft collision avoidance system

Surveillance with Mode A/C transponders. (Reprinted with permission of MIT Lincoln Laboratory, Lexington, MA)

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from article Aircraft collision avoidance system

TCAS pilot displays. (a) Traffic advisory (TA) display. (b) Vertical resolution advisory (RA) display. (Reprinted with permission of MIT Lincoln Laboratory)

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from article Pine

Mature sugar pine (Pinus lambertiana) in Sequoia National Park, California. (Photo courtesy of the National Park Service)

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from article Pine

Scots (Scotch) pine (Pinus sylvestris). (a) Female (ovulate) cone, unfertilized. (b) Fertilized cones. (c) Advanced stage in cone development. (d) Cone opening to discharge seeds. (e) Seed scale showing two winged seeds.

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from article Hickory

Leaves of pignut hickory (Carya glabra). (Photo by Robert H. Mohlenbrock, USDA–NRCS PLANTS Database)

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from article Biogeochemistry

Biogeochemistry is concerned with both the biological uptake and release of nutrients, as shown for nitrogen. (Credit: U.S. Geological Survey)

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from article Biogeochemistry

Carbon cycle. Photosynthetic fluxes between the atmosphere and oceans, and the atmosphere and land, represent net primary productivity. Reservoir units, gigatons (1015 g) C; flux units, gigatons C/yr.

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from article Biogeochemistry

Terrestrial nitrogen cycle; organic nitrogen includes both particulate and dissolved material. Flux units, teragrams (1012 g) N/yr.

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from article Biogeochemistry

Marine nitrogen cycle; organic nitrogen includes both particulate and dissolved material. Flux units, teragrams (1012 g) N/yr.

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from article Biogeochemistry

Phosphorus cycle. Reservoir units, teragrams (1012 g) P; flux units, teragrams P/yr.

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from article Biogeochemistry

Sulfur cycle. Reservoir units, teragrams (1012 g) S; flux units, teragrams S/yr.

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from article Field theory (mathematics)

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from article Field theory (mathematics)

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from article Speech perception

The perception of speech (as well as the production of speech) involves interactive processes occurring in various regions of the brain. Researchers also have noted the important contribution that vision makes to normal speech perception. (Copyright…

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from article Speech perception

An auditory spectrogram of the word "telephone." (a) The vertical striations in the bands represent amplitude modulation at the frequency of the voice pitch. Such striations are absent from the initial noise portion corresponding to the voiceless…

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from article Rice

A long-grain variety of rice (Oryza sativa) growing in a field. (Credit: Keith Weller/Agricultural Research Service, U.S. Department of Agriculture)

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from article Rice

Rice panicle. Each spikelet has a single caryopsis enclosed in the lemma and palea. A centimeter ruler is shown for measurement purposes. (Credit: Agricultural Research Service, U.S. Department of Agriculture)

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from article Rice

Rice grains. (Credit: Howard F. Schwartz/Colorado State University)

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from article Rice

Mechanical harvesting of rice on a farm in northern California. (Credit: Gary Kramer/Natural Resources Conservation Service, U.S. Department of Agriculture)

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from article Rice

Rice stem nodes affected by rice blast lesions. Rice blast is a fungal disease caused by Magnaporthe grisea. (Credit: Donald Groth/Louisiana State University AgCenter)

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from article Rice

Bacterial panicle blight (seen as a discoloration) on rice grains. This disease is caused by Burkholderia glumae. (Credit: Donald Groth/Louisiana State University AgCenter)

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from article Rice

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from article Sugar crops

Sugarcane (Saccharum officinarum) growing in Cuba. (Credit: Curioso Photography/Shutterstock)

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from article Sugar crops

Sugarbeets (Beta vulgaris). (Credit: Agricultural Research Service, U.S. Department of Agriculture)

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from article Information theory (biology)

Human information processing. The estimates of channel capacity are based on the number of rods in the retina of the eye and the number of hair cells in the inner ear's organ of Corti.

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from article Information theory (biology)

Flow diagram of communication.

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from article Information theory (biology)

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from article Information theory (biology)

Coupling diagram of communication.

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from article Kudzu

Spreading of kudzu (Pueraria montana var. lobata) over a Mississippi landscape. (Photo by Peggy Grub, Agricultural Research Service, U.S. Department of Agriculture)

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from article Biomass

Wood materials are common sources of biomass. They can be burned directly for energy or processed in industrial facilities to produce renewable biofuels. (Credit: alffoto/Getty Images)

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from article Biomass

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from article Biomass

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from article Invasive forest species

The emerald ash borer (Agrilus planipennis) is a destructive invasive forest species. Native to northeastern Asia, this wood-boring beetle has devastated large areas of forests in North America and Europe. (Credit: Benjamin Smith)

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from article Invasive forest species

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from article Logging

Feller-buncher cutting tree. (John Deere)

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from article Logging

Forwarder loading logs for transport to landing. (John Deere)

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from article Logging

Heavy-duty log truck-trailer being loaded with a grapple. Part of a steel yarding tower is visible at the left and is rigged with a skyline cable system. (Kenworth Truck Co., Division of PACCAR)

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from article Surface (geometry)

Part of a dihedron (the rest has been torn away), showing dihedral angle.

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from article Surface (geometry)

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from article Surface (geometry)

Some quadric surfaces, with parameters a, b, and c. (a) Ellipsoid; 0 < c < b < a. (b) Hyperboloid of one sheet; 0 < a < b < c. (c) Elliptic paraboloid; 0 < a < b and c > 0. (d) Hyperboloid of two sheets; 0 < a < b < c. (e) Hyperbolic paraboloid; c >…

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from article Surface (geometry)

Surface of revolution. The generating curve (in the yz plane) is f(y,z) = 0. The axis of revolution is the z axis.

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from article Surface (geometry)

Sphere, with a zone and a lune.

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from article Surface (geometry)

Catenoid. The axis of revolution is the y axis.

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from article Interpolation

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from article Interpolation

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from article Interpolation

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from article Autopilot

Basic elements of an autopilot system.

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from article Autopilot

Typical longitudinal autopilot control loop.

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from article Autopilot

Typical directional autopilot control loop.

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from article Plant

The kingdom Plantae contains a tremendous diversity of plants. The plants seen in the photograph are drought-tolerant varieties native to California and the Mediterranean region. (Credit: David Madison/Getty Images)

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from article Problem solving (psychology)

Composite view of a colorized magnetic resonance imaging (MRI) scan of a human brain blended with a cross-section illustration of a human head. Cognitive psychology attempts to understand the integral mental processes of the human brain involved in…

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from article Problem solving (psychology)

The game of chess involves many aspects of problem solving. In chess playing, a solution consists of an attempt to convert an initial state of a task (for example, a chessboard before the first move is made) into a final or goal state (checkmate)…

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from article Agricultural chemistry

Agricultural chemistry often involves the use of fertilizers to improve agricultural output and productivity. Urea (carbamide) fertilizers are notable sources of nitrogen, which is necessary for healthy plant growth and well-balanced soil…

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from article Forest measurement

Determination of tree height using common sighting instruments. (After T. E. Avery and H. E. Burkhart, Forest Measurement, 4th ed., McGraw-Hill, 1994)

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from article Forest measurement

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from article Forest measurement

Plan for a nominal 20% systematic strip inventory. Sample strips 1 chain (66 ft or 20 m) wide are spaced 5 chains (330 ft or 100 m) apart. (After H. E. Burkhart et al., Timber inventory, in K. F. Wenger, ed., Forestry Handbook, 2d ed., John Wiley,…

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from article Forest measurement

Plan for nominal 10% systematic plot inventory. Sample plots are circular, ⅕ acre (0.08 ha) in size, spaced at 4-chain (264-ft or 80-m) intervals on lines 5 chains (330 ft or 100 m) apart. (After H. E. Burkhart et al., Timber inventory, in K. F.…

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from article Forest measurement

Data from diverse sources can be stored, manipulated, and displayed by use of geographic information systems. (After T. E. Avery and H. E. Burkhart, Forest Measurements, 4th ed. McGraw-Hill, 1994)

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from article Forest measurement

The characteristic sigmoid growth curve of trees is illustrated by the cumulative height-growth pattern of some coniferous species (1 ft = 0.3 m). (After T. E. Avery and H. E. Burkhart, Forest Measurements, 4th ed., McGraw-Hill, 1994)

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from article Forest measurement