Acanthophractida | |
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Order: | Acanthophractida |
Acanthophractida is an order of marine radiolarians in the subclass Acantharia; skeleton includes a latticework shell and skeletal rods. [1] They have a latticework shell, which can be spherical or ovoid and fused with the skeletal rods. The shell is concentric with the central capsule. "The body is usually covered with a single or double gelatinous sheath through which the skeletal rods emerge". [2]
The drum is a member of the percussion group of musical instruments. In the Hornbostel-Sachs classification system, it is a membranophone. Drums consist of at least one membrane, called a drumhead or drum skin, that is stretched over a shell and struck, either directly with the player's hands, or with a percussion mallet, to produce sound. There is usually a resonant head on the underside of the drum. Other techniques have been used to cause drums to make sound, such as the thumb roll. Drums are the world's oldest and most ubiquitous musical instruments, and the basic design has remained virtually unchanged for thousands of years.
A skeleton is the structural frame that supports the body of an animal. There are several types of skeletons, including the exoskeleton, which is the stable outer shell of an organism, the endoskeleton, which forms the support structure inside the body, and the hydroskeleton, a flexible internal skeleton supported by fluid pressure. Vertebrates are animals with a vertebral column, and their skeletons are typically composed of bone and cartilage. Invertebrates are animals that lack a vertebral column. The skeletons of invertebrates vary, including hard exoskeleton shells, plated endoskeletons, or spicules. Cartilage is a rigid connective tissue that is found in the skeletal systems of vertebrates and invertebrates.
Hyoliths are animals with small conical shells, known as fossils from the Palaeozoic era. They are at least considered as lophotrochozoan, and possibly being lophophorates, a group which includes the brachiopods, while others consider them as being basal lophotrochozoans, or even molluscs.
An exoskeleton is an external skeleton that supports and protects an animal's body, in contrast to an internal skeleton (endoskeleton) in for example, a human. In usage, some of the larger kinds of exoskeletons are known as "shells". Examples of exoskeletons within animals include the arthropod exoskeleton shared by chelicerates, myriapods, crustaceans, and insects, as well as the shell of certain sponges and the mollusc shell shared by snails, clams, tusk shells, chitons and nautilus. Some animals, such as the turtle, have both an endoskeleton and an exoskeleton.
A barnacle is a type of arthropod constituting the subclass Cirripedia in the subphylum Crustacea, and is hence related to crabs and lobsters. Barnacles are exclusively marine, and tend to live in shallow and tidal waters, typically in erosive settings. They are sessile (nonmobile) and most are suspension feeders, but those in infraclass Rhizocephala are highly specialized parasites on crustaceans. They have four nektonic larval stages. Around 1,000 barnacle species are currently known. The name Cirripedia is Latin, meaning "curl-footed". The study of barnacles is called cirripedology.
The long bones are those that are longer than they are wide. They are one of five types of bones: long, short, flat, irregular and sesamoid. Long bones, especially the femur and tibia, are subjected to most of the load during daily activities and they are crucial for skeletal mobility. They grow primarily by elongation of the diaphysis, with an epiphysis at each end of the growing bone. The ends of epiphyses are covered with hyaline cartilage. The longitudinal growth of long bones is a result of endochondral ossification at the epiphyseal plate. Bone growth in length is stimulated by the production of growth hormone (GH), a secretion of the anterior lobe of the pituitary gland.
Coral sand is a collection of sand of particles originating in tropical and sub-tropical marine environments from bioerosion of limestone skeletal material of marine organisms. One example of this process is that of parrot fishes which bite off pieces of coral, digest the living tissue, and excrete the inorganic component as silt and sand. However, the term "coral" in coral sand is used loosely in this sense to mean limestone of recent biological origin; corals are not the dominant contributors of sand particles to most such deposits. Rather, remnant skeletal fragments of foraminifera, calcareous algae, molluscs, and crustaceans can predominate. Because it is composed of limestone, coral sand is acid-soluble.
Actinin is a microfilament protein. Alpha-actinin-1 is necessary for the attachment of actin myofilaments to the Z-lines in skeletal muscle cells, and to the dense bodies in smooth muscle cells. The functional protein is an anti-parallel dimer, which cross-links the thin filaments in adjacent sarcomeres, and therefore coordinates contractions between sarcomeres in the horizontal axis.
Minnesota Woman, also known as Pelican Rapids-Minnesota Woman, is the skeletal remains of a woman thought to be 8,000 years old. The bones were found near Pelican Rapids, Minnesota on June 16, 1931, during construction on U.S. Route 59. The bones were brought to Albert Jenks at the University of Minnesota, who identified them as the bones of a woman who was 15 or 16 years old, but who had never borne children. The woman had two artifacts—a dagger made from an elk's horn and a conch shell pendant. The conch shell came from a whelk species known as Sinistrofulgur perversum, which had previously only been known to exist in Florida.
In electronics, a ferrite core is a type of magnetic core made of ferrite on which the windings of electric transformers and other wound components such as inductors are formed. It is used for its properties of high magnetic permeability coupled with low electrical conductivity. Because of their comparatively low losses at high frequencies, they are extensively used in the cores of RF transformers and inductors in applications such as switched-mode power supplies, and ferrite loopstick antennas for AM radio receivers.
Latticework is an openwork framework consisting of a criss-crossed pattern of strips of building material, typically wood or metal. The design is created by crossing the strips to form a grid or weave. Latticework may be functional – for example, to allow airflow to or through an area; structural, as a truss in a lattice girder; used to add privacy, as through a lattice screen; purely decorative; or some combination of these.
In biology, a test is the hard shell of some spherical marine animals and protists, notably sea urchins and microorganisms such as testate foraminiferans, radiolarians, and testate amoebae. The term is also applied to the covering of scale insects. The related Latin term testa is used for the hard seed coat of plant seeds.
Bioclasts are skeletal fossil fragments of once living marine or land organisms that are found in sedimentary rocks laid down in a marine environment—especially limestone varieties around the globe. some of which take on distinct textures and coloration from their predominate bioclasts—that geologists, archaeologists and paleontologists use to date a rock strata to a particular geological era.
The 2000 Shell Championship Series was an Australian motor racing series open to V8 Supercars. The championship, which was the second Shell Championship Series, began on 11 February at the Phillip Island Grand Prix Circuit and ended on 19 November at the Mount Panorama Circuit after 13 rounds. Titles were awarded for drivers, teams and manufacturers by the series organisers AVESCO, and the winning driver, Mark Skaife, was also awarded the Australian Touring Car Championship by the Confederation of Australian Motor Sport, the 41st time that this title had been awarded.
engrailed is a homeodomain transcription factor involved in many aspects of multicellular development. First known for its role in arthropod embryological development, working in consort with the Hox genes, engrailed has been found to be important in other areas of development. It has been identified in many bilaterians, including the arthropods, vertebrates, echinoderms, molluscs, nematodes, brachiopods, and polychaetes. It acts as a "selector" gene, conferring a specific identity to defined areas of the body, and co-ordinating the expression of downstream genes.
A tom drum is a cylindrical drum with no snares, named from the Anglo-Indian and Sinhala language. It was added to the drum kit in the early part of the 20th century. Most toms range in size between 6 and 20 inches in diameter, though floor toms can go as large as 24 inches (61 cm). It is not to be confused with a tam-tam, a gong.
Ethiopian crosses, Abyssinian crosses, or Ethiopian-Eritrean crosses are a grouping of Christian cross variants that are symbols of Christianity in Ethiopia, Eritrea, and among Ethiopians and Eritreans. Their elaborate, stylized design is markedly distinct from other Christian cross variants. Ethiopian crosses are almost always made from elaborate latticework, the intertwined lattice represents everlasting life. No two crosses are exactly identical in style, the artisans who make them being allowed the freedom to exercise a measure of individual taste and creativity in their choice of shape and pattern. Crosses may be of the processional type with a socket at the base so they may be mounted on a staff and carried in church ceremonies or hand-held blessing crosses used by priests in benedictions.
Cyamodontoidea is an extinct superfamily of placodont marine reptiles from the Triassic period. It is one of the two main groups of placodonts, the other being Placodontoidea. Cyamodontoids are distinguished from placodontoids by their large shells, formed from fused bony plates called osteoderms and superficially resembling the shells of turtles. Cyamodontoids also have distinctive skulls with narrow, often toothless jaws and wide, flaring temporal regions behind the eyes. Two large temporal openings are positioned at the top of the back of the skull, an arrangement that is known as the euryapsid condition and seen throughout Sauropterygia, the marine reptile group to which placodonts belong. Cyamodontoids are also distinguished by their large crushing teeth, which grow from the palatine bones on the roof of the mouth.
The Museum of European and Mediterranean Civilisations is a national museum located in Marseille, France. It was inaugurated on 7 June 2013 as part of Marseille-Provence 2013, a year when Marseille was designated as the European Capital of Culture. In 2015, it won the Council of Europe Museum Prize.