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DEFINITION: Point of detonation of an explosive device.

Lichens are very common organisms found in widely diverse habitats, including rock surfaces, trees, and human-made structures. Lichens use structures on which they grow as hosts to support their growth. They are composites, composed of two different organisms, an alga and a fungus, resulting in a symbiotic organism that has a morphology very different from the two original organisms. In lichen symbiosis, the alga provides energy through photosynthesis and the fungus provides protection and support. Lichens come in three types: crustose, a crusty form that grows tightly on rocks or trees; foliose, which resembles foliage; and fruticose, which has the appearance of “fingers.” Lichens provide food for animals, such as reindeer living in arctic regions, and habitat for invertebrates. Lichens absorb nutrients from air and rain and are an important part of nutrient recycling. They grow very slowly, with rates less than 5 millimeters per year. Some species even have growth rates of less than 0.5 millimeter per year. Lichens often live for long periods of time, with some species in the arctic estimated to be over five thousand years old.

In chemical analysis, the components of a sample are identified and their concentrations determined. The main objective of qualitative analysis is to identify one or more substances or chemicals that may be present in a sample. The main goal of quantitative analysis is to determine how much of a particular chemical or substance is present in the sample. Most forensic analysis techniques currently in use are qualitative and are used to identify or confirm the presence or absence of certain materials. Subsequent analyses provide additional information, such as the amounts of component substances present in a sample. Forensics scientists conduct qualitative and quantitative analyses on chemical components of materials, objects, solutions, and biological specimens, including body fluids.

DEFINITION: Chemical agents that affect the body by being absorbed into the blood.

DEFINITION: Technique that employs special filters to enhance microscopic images.

DEFINITION: Technique used in examining evidence that involves lighting an object from different angles to enhance the visibility of its surface features.

DEFINITION: Technique used to identify the components of very small samples through the combination of microscope and spectrophotometer.

The sun produces ultraviolet (UV) light. UV light is a portion of the electromagnetic spectrum with wavelengths shorter than those of visible light but longer than those of x-rays. UV light wavelengths—shorter than the shortest wavelength of visible light, violet—are too short to be seen by the human eye (ultraviolet literally means “beyond violet”). UV radiation produced by the sun is commonly split into three bands: UV-A, with wavelengths of 320-400 nanometers; UV-B, with wavelengths of 320-280 nanometers; and UV-C, with wavelengths of 200-280 nanometers. Most people are familiar with UV light through the painful effects of sunburn. A small amount of UV radiation is necessary for the well-being of humans and other organisms because it promotes vitamin D synthesis in humans and acts as a germicide, controlling microbial growth. Too much UV radiation, however, is associated with many harmful effects.

Composting is a natural biological process that breaks down organic materials into a stable organic substance called compost. Compost is created by combining organic wastes, such as yard trimmings, food wastes, and manures, in piles or containers. Microorganisms, primarily bacteria and fungi, decompose and form compost, a nutrient-rich material that is also called humus. Humus is dark brown or black in color and is free of most and weed seeds. Compost can either be added to soil as fertilizer or be used to support plant growth. Composting is used in landscaping, horticulture, and agriculture as an organic fertilizer to enrich soils. Compost is also used for erosion control, wetland construction, and as landfill cover. Industrial composting systems are increasingly being utilized as landfill alternatives, making them an important tool for waste management.

Few natural resources of significant economic value remain in Taiwan. After many decades of mining, almost all metallic minerals, coal, and talc have been depleted in the twenty-first century. Most of the country’s oil, gas, and power needs must be met through importing, although Taiwan aims to develop renewable energy using wind and solar power. In 2019, only 6 percent of total electricity supply in the country was derived from renewable sources. Taiwan’s export-oriented economy depends on the world's global economy for growth.

Semiconductor materials are found all over the world. The most frequently used semiconductor materials are composed of crystalline inorganic solid elements found in nature, with silicon the most common semiconductor material. Standardized semiconductor crystals are grown in laboratories, with the global semiconductor industry dominated by Taiwan, South Korea, the United States, and Japan. By 2024, Taiwan had become the world's largest producer of semiconductors, with more than 60 percent of the global market.

The aseptic technique involves applying preventive measures to minimize the chance of introducing into clinical settings the microorganisms, such as viruses and harmful bacteria (known as pathogens), that cause disease. In other words, its purpose is to maintain asepsis, or the absence of pathogens, in clinical settings. The aseptic technique is intended to protect the patient and the healthcare worker from pathogens and to prevent their spread.

Proteins are composed of twenty-two different amino acids in various combinations, joined together in a chain. The human body can synthesize fourteen amino acids, known as inessential amino acids, whereas the other eight, known as essential amino acids, must be provided by the diet.

DEFINITION: Analytical chemistry technique used as a screening tool in classifying chemical compounds.

DEFINITION: Predatory, carnivorous mammals of the family Canidae

DEFINITION: Large herbivorous mammals native to Africa and southern Asia

DEFINITION: Nonfiction writing about the natural environment

Tundra ecosystems are treeless regions found in the Arctic and on mountaintops. The word “tundra” is derived from the Finnish word tunturi, which refers to treeless areas of hills and mountains. There are two types of tundra: those in the north, called Arctic tundra, and those in high mountains, called alpine tundra. Antarctica has some tundra as well. Tundra climate is very harsh, involving extremely cold and snowy winters and short, cool summers with very little precipitation. In the Arctic tundra, the average temperature is between -12° and -7° Celsius. Most Arctic tundra regions have permafrost, a layer of ground below the surface soil that remains permanently frozen. The tundra landscape is shaped by periodic freezing and thawing of soil, which forms cracks and alters drainage.

Warmer temperatures and air pollution are interrelated: Rising temperatures result in increases in ozone production and energy utilization. Increased energy demands result in more power plant utilization, which leads to greater emissions.

DATE: Established 1973

SIGNIFICANCE: The SCLC1 gene is expressed in cells and tissues of individuals with lung cancer, particularly small-cell cancer of the lung. Interactions between cigarette smoking and acquired chromosomal abnormalities facilitate expression of this gene.

ALSO KNOWN AS: Isolated sulfite oxidase deficiency; sulphite oxidase deficiency

The incubation period is the time between exposure to a virus or bacterium and the development of symptoms.

The immune system defends itself against infectious organisms (pathogens) such as bacteria by utilizing physical barriers that prevent bacteria from entering the body and by detecting and eliminating bacteria after they enter the body. Cells, proteins, tissues, and organs work together in a coordinated response, the immune response, to defend against microorganisms.

DEFINITION: Anthraquinones are derived from plant products. Anthraquinones naturally occur in some plants, such as aloe, senna, rhubarb, Cascara buckthorn, and sheep sorrel. Indian rhubarb root (Rheum palmatum) contains several anthraquinones. Sheep sorrel (Rumex acetosella) also includes several types of anthraquinones. Subclasses of this group are emodin, aloe emodin, and anthraquinone derivatives.

ATC CODE: 101

ATC CODE: 101C

ALSO KNOWN AS: Bone marrow transplantation (BMT), peripheral blood stem cell transplantation (PBSCT), umbilical cord blood stem cell transplant