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from article Tomato
Tomato affected by anthracnose (caused by the fungus Colletotrichum phomoides). (Credit: U.S. Department of Agriculture Cooperative Extension Slide Series, Clemson University)
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from article Tomato
Tomatoes showing blossom-end rot. (Credit: Mary Ann Hansen, Virginia Polytechnic Institute and State University)
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from article Ohmmeter
Electronic digital ohmmeter. (Tinsley)
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from article Ohmmeter
Diagram of ohmmeter, showing operating principles. C1, C2 = current terminals; P1, P2 = potential terminals.
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from article Ohmmeter
Special measuring probes (Kelvin clips), consisting of a set of leads with combined current probes (C1, C2) and potential probes (P1, P2).
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from article Cavity resonator
Closed-end sound pipe resonating (a) at the fundamental frequency f1 (the first harmonic) with wavelength λ1, and (b) at an overtone, f3 ≈ 3f1 (the third harmonic), with wavelength λ3.
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from article Cavity resonator
Wavemeters. (a) Wavemeter consisting of cylindrical cavity with an adjustable end-wall, resonating in the TE011 mode. The free-space wavelength λ0 corresponding to the resonant frequency f0 is given by λ0 = 2L[1 + (2L/1.64a)]− 1 2 . (b) Practical…
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from article Cavity resonator
Determination of the Q of a cavity resonator by (a) measuring the bandwidth and (b) measuring the damping rate of the oscillations.
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from article Lens (optics)
Refraction of light waves demonstrated by the disjointed appearance of a spoon entering a bowl of water, as well as the transposition of background colors due to the bowl's curvature. (Credit: Copyright © McGraw Hill)
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from article Lens (optics)
Illustration of a standard concave lens (left) that acts as a diverging lens and a standard convex lens (right) that acts as a converging lens.
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from article Learning
Lateral view of the human brain, including the primary areas of the frontal, temporal, parietal, and occipital lobes. (Copyright © McGraw-Hill Education)
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from article Learning
Brain activity can be recorded in various ways, from single-cell activity (top tracing) to the familiar electrical patterns ("brain waves") of an electroencephalogram (bottom tracing). (Credit: Based on an original drawing by C. Cotman and J.…
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from article Pine nut
Pine nuts in their hard shell (Mexican piñon pine, Pinus cembroides). (Photo by Steve Hurst, U.S. Department of Agriculture–Natural Resources Conservation Service PLANTS Database)
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from article Pine nut
Cone containing pine nuts (stone pine, Pinus pinea). (Photo by Vito Buono, Bari, Italy)
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from article Biofilm
Biofilms are highly structured communities of microorganisms that are surface-associated or attached to one another, and are enclosed within a self-produced protective extracellular matrix. Biofilm formation and actions involve a number of stages:…
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from article Pyroclastic rock
Pyroclastic rock. Bombs from Mauna Kea, Hawai'i, USA. (Credit: J. P. Lockwood/USGS Photo Library, Denver, CO)
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from article Pyroclastic rock
Distribution downwind of the pyroclastic fall deposit from the climactic eruption of Mount St. Helens, Washington, on May 18, 1980. The contours (isopachs) are drawn through points of measured equal thickness (in centimeters) of this ash layer.…
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from article Pyroclastic rock
Aerial view in March 1998 of the fan-shaped pyroclastic delta formed by repeated entries of pyroclastic flows and surges into the Caribbean Sea during the Soufrière Hills Volcano eruption in 1996–1997. (Credit: R.P. Hoblitt, USGS)
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from article Pyroclastic rock
Observed or postulated mechanisms for the generation of pyroclastic flow and surge deposits. (a, b) Mechanisms that commonly produce block-and-ash flow deposits. (b, c) Mechanisms that trigger laterally directed blasts. (d–f) Mechanisms that…
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from article Pyroclastic rock
Some variations in pyroclastic rock formations. (a) Layers of pyroclastic fall deposits from the eruption plume of the June 15, 1991, explosive eruption of Mount Pinatubo (Luzon, Philippines). This exposure, located about 9 km (5.5 mi) southeast of…
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from article Equisetales
Equisetum arvense. (a) Sterile shoot. (b) Fertile shoot growing from an underground rootstock. (c) Cone. (d) Two views of shield-shaped sporangiophores. (e) Spores, greatly enlarged. As spore dries, elaters expand. (After E. W. Sinnott and K. S.…
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from article Equisetales
Equisetum gametophyte. (a) Small gametophyte, showing antheridia only. (b) Male gametes. (c) Larger gametophyte; branching lobes have archegonia at bases. (After E. W. Sinnott and K. S. Wilson, Botany: Principles and Problems, 6th ed., McGraw-Hill,…
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from article Equisetales
Sporophytes. (a) Equisetum gametophyte with sporophytes. (b, c, d) The young sporophytes of Equisetum hiemale. (After G. M. Smith, Cryptogamic Botany, vol. 2, 2d ed., McGraw-Hill, 1955)
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from article Lung
Human lungs. (a) The trachea bifurcates as the right and left primary bronchi that enter each lung. The bronchi subdivide further to form the bronchial tree. (b) Color-coded view of the major branches of the bronchial tree. (Copyright © McGraw Hill)
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from article Dewar flask
Two typical Dewar containers.
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from article Animal testing
Mice are the most commonly used vertebrate species in animal testing and research. (Credit: Dolores Bonaparte)
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from article Animal testing
The use of animals in biomedical research remains essential, but the handling of these sentient beings must be done humanely to minimize and prevent animal harm. (Credit: U.S. Department of Agriculture)
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from article Propagator (field theory)
Feynman diagrams for scattering processes. (a) Electron-proton scattering via photon exchange. (b) Proton-proton scattering via meson exchange.
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from article Common cold
Adenovirus structure. An adenovirus binds to the host cell via its fiber through the knob at the end of the fiber "spikes" on the capsid (protein coat) surface. (Credit: M. K. Cowan and H. Smith; copyright © McGraw Hill)
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from article Common cold
Human respiratory system. Common cold viruses enter through the nose, mouth, or eyes, infecting epithelial cells of the oropharynx. (Credit: M. K. Cowan and H. Smith; copyright © McGraw Hill)
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from article Common cold
Life cycle of a double-stranded DNA virus, such as an adenovirus. The virus attaches to specific receptors, after which it is taken up by the cell. Following entry into the cell, the viral capsid (protein coat) is digested, releasing DNA, which…
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from article Common cold
Electron micrograph (tinted green) of human coronavirus 229E particles. Coronaviruses are named for the corona, or halo, surrounding the capsid (protein coat). The crown-like corona results from the presence of viral spikes protruding from the viral…
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from article Conservation of energy
The conservation of energy allows energy to be interconverted among many different forms. In the use of wind power, for example, the kinetic energy of wind (movements of air) can be converted by turbine blades into electrical energy. (Credit: Ron…
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from article Pathotoxin
Oat seedling resistant to Victoria blight obtained by screening a susceptible population with the pathotoxin victorin, a product of the pathogen Helminthosporium victoriae.
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from article Pathotoxin
Separation of corn seedlings resistant (N) and susceptible (T) to southern corn leaf blight by treatment with a pathotoxin produced by Helminthosporium maydis race T.
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from article Pathotoxin
Chemical structures of four pathotoxins. (a) Fusicoccin. (b) Tentoxin. (c) AM-toxin. (d) HMT-toxin.
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from article Electrical units and standards
Calculable capacitor. (a) Cross section of general cylindrical capacitor with four segments. (b) Cross section of symmetrical capacitor with cylindrical electrodes. (c) Calculable capacitor used in absolute determination of the ohm. (U.S. National…
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from article Electrical units and standards
Moving-coil balance. (a) Schematic diagram. (b) Equipment. (U.K. National Physical Laboratory)
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from article Electrical units and standards
Josephson effect. (a) Josephson junction characteristic. (b) Linear array of more than 2000 Josephson junctions in a folded microwave stripline, giving a total voltage step in the region of 1 volt. (U.S. National Institute of Standards and…
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from article Electrical units and standards
Quantum Hall effect. (a) Geometry of semiconductor. (b) Hall resistance characteristic. i = quantum number.
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from article Tree ferns
Cyathea cooperi (Australian tree fern), a common member of the family Cyatheaceae. (Photo by Forest and Kim Starr)
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from article Tree ferns
Arrangement of leaves of Cyathea cooperi (Australian tree fern). (Photo by Bryan Harry, Haleakalā National Park, National Park Service, Maui, Hawaii)
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from article Earth's interior
Speculative models of the interiors of the terrestrial planets. All are rocky, divided into a crust (not shown here), mantle, and metallic core. (After R. T. Merrill and M. W. McElhinny, The Earth's Magnetic Field, Academic Press, 1983)
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from article Earth's interior
Preliminary Reference Earth Model (PREM) for P- and S-wave velocities, vp and vs, and density ρ. In the part of the upper mantle where the model is anisotropic, velocities are given in both the vertical and horizontal direction. The broken lines…
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from article Earth's interior
Variations of gravity and pressure inside the Earth. 1 m = 3.3 ft. 1 megabar = 100 GPa. (After P. Melchior, The Physics of the Earth's Core, Pergamon Press, 1986)
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from article Earth's interior
Density versus depth for several mantle constituents along the 1400°C (2552°F) adiabat. Data points show the density variation of PREM. All three constituents shown here contain magnesium-rich silicates. (After D. L. Anderson, Where on Earth is the…
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from article Earth's interior
P-wave velocity anomalies above the core–mantle boundary in terms of spherical harmonics up to degree and order 6, obtained by inverting P-wave travel time data. Positive perturbations indicate faster-than-average material. Contour interval = 25…
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from article Earth's interior
Speculative, schematic model of the core–mantle boundary layer. A heterogeneous chemical boundary layer is embedded in a thermal boundary layer. Large-scale mantle circulation transports chemical heterogeneity to the base of the mantle as well as…
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from article Earth's interior
Schematic temperature profile of the mantle. Subsequent estimates of core temperature are higher than suggested in the figure; the temperature jump across the thermal boundary layer at the base of the mantle will then be correspondingly higher. °F =…
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from article Earth's interior
Schematic temperature profile of the core. The melting-point curve for the core is substantially below the melting point of pure iron. All temperatures may have to be raised to correspond with further estimates of the melting point of iron. °F = (K…
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from article Earth's interior
Contour plots of the radial component of the magnetic field at the core–mantle boundary (a) for the year 1715 and (b) for 1980. The contour interval is 100 microteslas; solid-line contours represent flux into the core, and broken-line contours…
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from article Circadian clock (plants)
Three-module circadian clock system.
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from article Circadian clock (plants)
Model of the Arabidopsis circadian clock, showing light input (bold arrow), the central oscillator (large box) and output/response (tinted arrows). Light signals synchronize the clock via the cryptochromes (cry) and phytochromes (phy). These are…
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from article Anthrax
A color-enhanced scanning electron micrograph showing splenic tissue from a monkey with inhalation anthrax. Rod-shaped bacilli of Bacillus anthracis (yellow) and an erythrocyte (red) are shown. (Credit: Arthur Friedlander/National Institute of…
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from article Anthrax
Micrograph (stained with hematoxylin and eosin) showing submucosal hemorrhage in the small intestine of a person fatally affected by gastrointestinal anthrax. (Credit: Marshal Fox/Centers for Disease Control and Prevention)
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from article Neuron
Typical vertebrate neurons, including the sending neuron and the receiving neuron. (Copyright © McGraw Hill)
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from article Triple point
Phase diagram for water, showing gas, liquid, and several solid (ice) phases; triple points at A, B, and C. The pressure scale changes at 101 kilopascals from logarithmic scale at low pressure to linear at high pressure.
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from article Tumor virus
Under certain conditions, human papillomaviruses are capable of causing cancer in humans. (Credit: Laboratory of Tumor Virus Biology, National Cancer Institute)
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from article Mutagens and carcinogens
Arsenic is a known carcinogen. In this graphical example, more than half of the mice exposed to arsenic in their drinking water [at concentration levels of 50 and 500 parts per billion (ppb)] showed increased incidences of lung tumors (compared to a…
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from article Mutagens and carcinogens
Proflavin is a chemical disinfectant agent against bacteria, causing mutagenic DNA changes (such as the insertion or deletion of a DNA base pair). However, it is carcinogenic in mammals. Thus, it is used only for the disinfecting of surfaces or for…
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from article Mutagens and carcinogens
Model of carcinogenesis. Changes often occur in the growth properties of normal cells, leading to cancer cells that are not responsive to normal regulatory controls and can eventually give rise to a visible neoplasm or tumor. The main stages of the…
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from article Autophagy
Modes of autophagy in yeast and mammalian cells. Macroautophagy involves the uptake of cytoplasm at a site away from the lysosome or vacuole. The origin of the sequestering membrane is not known, but it likely includes multiple sources such as the…
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from article Autophagy
Basic steps involved in macroautophagy, shown with the structural intermediates. See the text for full details.
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from article Autophagy
The cytoplasm-to-vacuole targeting (Cvt) pathway is an example of selective autophagy. The schematic illustrates the steps of the Cvt pathway and also shows electron micrographs of the sequestration event. Precursor aminopeptidase I (prApe1) forms a…
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from article Autophagy
Atg8 tagged with white fluorescent protein (GFP-Atg8) can be used to monitor autophagosome formation. Cells in growing conditions (for example, in the presence of nitrogen; +N) carry out a basal level of macroautophagy and typically display a single…
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from article Inertial confinement fusion
Ablative indirect drive and ablative direct drive. (a) In laser-illuminated, ablative indirect drive, the ICF target consists of a cylindrical hohlraum (hollow room) in which laser light is injected through the two holes in the end caps and heats…
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from article Inertial confinement fusion
X-ray images with a framing camera (developed at Lawrence Livermore National Laboratory) from a directly driven inertial confinement fusion capsule at the University of Rochester's Omega Facility. The camera has 80-ps exposure time and 55-ps time…
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from article Inertial confinement fusion
Deuterium–tritium fuel ion temperature and density at ignition, plotted against normalized radius, for a typical high-gain capsule.
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from article Inertial confinement fusion
The National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL). Its driver is the world's largest laser. The 1.8 MJ of ultraviolet light (351-nm wavelength from frequency-tripled neodymium:glass laser light) is generated with…
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from article Inertial confinement fusion
Progress toward ignition on NIF is illustrated by the plot of no-burn D–T equivalent yield in number of neutrons versus the value of ρr inferred from the energy lost by fusion neutrons during passage out of the compressed fuel. These experiments…
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from article Inertial confinement fusion
View of the combined Z Machine and Z-Beamlet laser facility (lower left) with exploded view of the cross section of the Z Machine (upper left). Both will be used to drive the MagLIF capsule (right) at Sandia National Laboratories. The 10-kJ…
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from article Inertial confinement fusion
Computed capsule gains (energy yield divided by absorbed energy) from 1D simulations of the principal (radial) dynamics for ablative direct drive of a perfect capsule, which is irradiated by either 248-nm laser light or 351-nm laser light with…
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from article Inertial confinement fusion
Electra, an ∼500 J/pulse, electron-beam pumped KrF laser at the Naval Research Laboratory. It has achieved 90,000 shots in a continuous run and 330,000 shots in 8 days at 2.5–5 Hz.
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from article Inertial confinement fusion
Conceptual design of the X-target. (Credit: Heavy Ion Fusion Science Virtual National Laboratory)
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from article Renner-Teller effect
Bending potential function V for a degenerate electronic state of a linear molecule as a function of displacement r, and for three values (0, 0.5, 1.0) of the Renner parameter ε. In the absence of Renner-Teller splitting (ε = 0) there is a single…
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from article Cell cycle
Phases of the eukaryotic cell cycle. Interphase is subdivided into three phases: gap phase 1 (G1), synthesis (S), and gap phase 2 (G2). M phase, which follows interphase, consists of mitosis (nuclear division) and cytokinesis (cell division). G0…
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from article Cell cycle
During cytokinesis (cell division), the cell pinches into two parts between the separated daughter nuclei. At the end of this process, the two daughter cells often remain tethered by a thin "midbody" of microtubules. Once this midbody breaks, the…
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from article Cell cycle
Behavior of various Cdk/cyclin complexes and their cellular events. (Copyright © McGraw Hill)
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from article Capacitance
Parallel-plate capacitor P1, P2 with guard ring GG. Spacing between guard ring and plate is exaggerated. (a) Cross section with all parts of capacitor at ground potential. (b) Top view showing plate P1 surrounded by guard ring. (c) Cross section of…
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from article Capacitance
Variable air capacitor.
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from article Capacitance
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from article Capacitance
Wound-roll construction of plastic film and paper capacitors.
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from article Capacitance
Ceramic capacitor constructed in chip form, showing cutaway of finished chip.
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from article Capacitance
Tantalum electrolytic capacitor showing cross section. (General Electric Co.)
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from article Capacitance
Construction and polarity markings of aluminum electrolytic capacitor. (a) Cross section. (b Polarization markings for tabular capacitor with axial leads. (c) Polarization markings for capacitor with radial leads. (After A. Mottershead, Electricity…
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from article Capacitance
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from article Pituitary gland
The pituitary, also known as the hypophysis, is a pea-sized gland situated at the base of the brain. The hypothalamus is designed and anatomically positioned to receive a diversity of messages from external and internal sources that can be…
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from article Pituitary gland
Anatomy of the pituitary gland. (Copyright © McGraw Hill)
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from article Salicylate
Chemical structures of (a) salicylate, the conjugate base of (b) salicylic acid, and the nonsteroidal anti-inflammatory drug (NSAID) (c) acetylsalicylic acid (aspirin).
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from article Meningococcus
A photomicrograph reveals the presence of the bacterium Neisseria meningitidis, which can be pathogenic, leading to meningococcal meningitis. (Credit: James Volk/Centers for Disease Control and Prevention)
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from article Hydrological consequences of global warming
The hydrologic cycle is characterized by evaporation and transpiration from the surfaces; transport of water vapor in the atmosphere by the wind, clouds, and precipitation; and water storage in snow, glaciers, groundwater, and oceans. Units: 1000…
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from article Hydrological consequences of global warming
Spatial patterns of climate model projections of (a) precipitation, (b) soil moisture, (c) runoff, and (d) evaporation for 2090–2099 under the mid-range A1B emission scenario from the Intergovernmental Panel for Climate Change 2007. (Climate Change…
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from article Oxygen toxicity
The dual effect of oxygen on biologic activity. Organisms that avail themselves of the enormous metabolic advantages provided by dioxygen (O2) must defend themselves against its toxicity. (Copyright © McGraw Hill)
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from article Transmission lines
Two common transmission lines for communication. (a) Coaxial cable. (b) Strip line.
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from article Transmission lines
Equivalent circuit that represents three sections of a lossless transmission line. Each section is of length Δz, and has an inductor (L) and capacitor (C). Voltages (V ) and currents (I ), and their differences (ΔV and ΔI ) between successive…
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from article Transmission lines
Signal detection on an oscilloscope. (a) Oscilloscope pictures of voltage pulses at three locations, z1, z2, and z3, on a transmission line, successively more distant from the signal generator. (b) Oscilloscope pictures of a periodic voltage sine…
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from article Transmission lines
Transmission line with characteristic impedance Zc, terminated in a load impedance ZL. A change of coordinate system (from z to ζ) is indicated.
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from article Transmission lines
Envelope of the voltage standing wave consisting of a wave propagating from z = −∞ and being reflected at z = 0. The wavelength, λ, and the maximum and minimum voltages, Vmax and Vmin , are indicated.
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from article Transmission lines
Two waveguides, with conventional coordinates. (a) Rectangular waveguide. (b) Cylindrical waveguide.
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from article Transmission lines
Dispersion curve for a rectangular waveguide of width a, showing relationship between the propagation constant, β, and the angular frequency, ω. Here, n specifies the mode of propagation, and c is the speed of light.
