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Tree-of-Life
Pak Breeders and Pak Protectors are two developmental stages of fictional life in Larry Niven's Known Space universe. The Pak first appeared in "The Adults", which appeared in ''Galaxy'' in 1967; this story was expanded into the novel ''Protector'' by Larry Niven (1973). The Pak also appear in several of Niven's later novels, notably those set in the Ringworld. '' Destroyer of Worlds'' depicts a confrontation between the Pak and the Puppeteers. Narrative purpose Niven has written that he invented the Protectors as a thought experiment to explain the common effects of aging on humans and to create a fictional evolutionary explanation for humans' long lives after females have passed reproductive age. Accordingly, most of the positive attributes of Protectors are based on negative human aging effects: swollen joints, decreased muscle-fat ratio, weakening heart, invariant diet, decreasing height, facial atrophy, leathery skin, hair loss, lack of sex drive, and tooth loss are all ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amalgamated Regional Militia
Known Space is the fictional setting of about a dozen science fiction novels and several collections of short stories by American writer Larry Niven. It has also become a shared universe in the spin-off '' Man-Kzin Wars'' anthologies. The Internet Speculative Fiction Database (ISFDB) catalogs all works set in the fictional universe that includes Known Space under the series name Tales of Known Space, which was the title of a 1975 collection of Niven's short stories. The first-published work in the series, which was Niven's first published piece, was "The Coldest Place", in the December 1964 issue of '' If'' magazine, edited by Frederik Pohl. This was the first-published work in the 1975 collection. The stories span approximately one thousand years of future history, from the first human explorations of the Solar System to the colonization of dozens of nearby systems. Late in the series, Known Space is an irregularly shaped "bubble" about 60 light-years across. The epithet "Kn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protector (novel)
''Protector'' is a 1973 science fiction novel by American writer Larry Niven, set in his Known Space universe. It was nominated for the Hugo in 1974, and placed fourth in the annual Locus poll for that year. The work fleshes out a species called the Pak, originally introduced in a 1967 story called "The Adults", which forms the first half of the novel (there titled ''Phssthpok''); the second half is titled ''Vandervecken''. The Pak also appear in several of Niven's later works, including the later volumes of the ''Ringworld'' series and the novel '' Destroyer of Worlds'' which serves as a semi-sequel to ''Protector''. Plot summary The novel comprises two phases in the same space that are separated by 220 years of time. Its central conceit is that Humans evolved from the juvenile stage of the Pak, a species with a distinct adult form ("Protectors") that has immense strength and intelligence and cares only about younger Pak of their bloodline. A key plot point is that tra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Skull
The skull, or cranium, is typically a bony enclosure around the brain of a vertebrate. In some fish, and amphibians, the skull is of cartilage. The skull is at the head end of the vertebrate. In the human, the skull comprises two prominent parts: the neurocranium and the facial skeleton, which evolved from the first pharyngeal arch. The skull forms the frontmost portion of the axial skeleton and is a product of cephalization and vesicular enlargement of the brain, with several special senses structures such as the eyes, ears, nose, tongue and, in fish, specialized tactile organs such as barbels near the mouth. The skull is composed of three types of bone: cranial bones, facial bones and ossicles, which is made up of a number of fused flat and irregular bones. The cranial bones are joined at firm fibrous junctions called sutures and contains many foramina, fossae, processes, and sinuses. In zoology, the openings in the skull are called fenestrae, the most ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coconut
The coconut tree (''Cocos nucifera'') is a member of the palm tree family (biology), family (Arecaceae) and the only living species of the genus ''Cocos''. The term "coconut" (or the archaic "cocoanut") can refer to the whole coconut palm, the seed, or the fruit, which botanically is a drupe, not a Nut (fruit), nut. Originally native to Central Indo-Pacific, they are now ubiquitous in coastal tropical regions and are a cultural icon of the tropics. The coconut tree provides food, fuel, cosmetics, folk medicine and building materials, among many other uses. The inner flesh of the mature seed, as well as the coconut milk extracted from it, forms a regular part of the diets of many people in the tropics and subtropics. Coconuts are distinct from other fruits because their endosperm contains a large quantity of an almost clear liquid, called "coconut water" or "coconut juice". Mature, ripe coconuts can be used as edible seeds, or processed for Coconut oil, oil and Coconut milk, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moment (physics)
A moment is a mathematical expression involving the product of a distance and a physical quantity such as a force or electric charge. Moments are usually defined with respect to a fixed reference point and refer to physical quantities located some distance from the reference point. For example, the moment of force, often called torque, is the product of a force on an object and the distance from the reference point to the object. In principle, any physical quantity can be multiplied by a distance to produce a moment. Commonly used quantities include forces, masses, and electric charge distributions; a list of examples is provided later. Elaboration In its most basic form, a moment is the product of the distance to a point, raised to a power, and a physical quantity (such as force or electrical charge) at that point: : \mu_n = r^n\,Q, where Q is the physical quantity such as a force applied at a point, or a point charge, or a point mass, etc. If the quantity is not concen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Femoral Vein
In the human body, the femoral vein is the vein that accompanies the femoral artery in the femoral sheath. It is a deep vein that begins at the adductor hiatus (an opening in the adductor magnus muscle) as the continuation of the popliteal vein. The great saphenous vein (a superficial vein), and the deep femoral vein drain into the femoral vein in the femoral triangle when it becomes known as the common femoral vein. It ends at the inferior margin of the inguinal ligament where it becomes the external iliac vein. Its major tributaries are the deep femoral vein, and the great saphenous vein. The femoral vein contains valves. Structure The femoral vein bears valves which are mostly bicuspid and whose number is variable between individuals and often between left and right leg. Course The femoral vein continues into the thigh as the continuation from the popliteal vein at the back of the knee. It drains blood from the deep thigh muscles and thigh bone. Proximal to th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genocide
Genocide is violence that targets individuals because of their membership of a group and aims at the destruction of a people. Raphael Lemkin, who first coined the term, defined genocide as "the destruction of a nation or of an ethnic group" by means such as "the disintegration of [its] political and social institutions, of [its] cultural genocide, culture, linguicide, language, national feelings, religious persecution, religion, and [its] economic existence". During the struggle to ratify the Genocide Convention, powerful countries restricted Lemkin's definition to exclude their own actions from being classified as genocide, ultimately limiting it to any of five "acts committed with intent to destroy, in whole or in part, a national, ethnical, racial or religious group". While there are many scholarly Genocide definitions, definitions of genocide, almost all international bodies of law officially adjudicate the crime of genocide pursuant to the Genocide Convention. Genocide has ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thallium Oxide
Thallium has several oxides: * Thallium(I) oxide Tl2O *Thallium(III) oxide Thallium(III) oxide, also known as thallic oxide, is a chemical compound of thallium and oxygen. It occurs in nature as the rare mineral avicennite. Its structure is related to that of Mn2O3 which has a bixbyite like structure. Tl2O3 is metallic ... Tl2O3 * Thallium(I) superoxide or thallium dioxide TlO2 * Tl4O3 {{Short pages monitor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Abundance Of Elements In Earth's Crust
The abundance of elements in Earth's crust is shown in tabulated form with the estimated Earth's crust, crustal abundance for each chemical element shown as mg/kg, or parts-per notation, parts per million (ppm) by mass (10,000 ppm = 1%). Reservoirs The Earth's crust is one "reservoir" for measurements of abundance. A reservoir is any large body to be studied as unit, like the ocean, atmosphere, mantle or crust. Different reservoirs may have different relative amounts of each element due to different chemical or mechanical processes involved in the creation of the reservoir. Difficulties in measurement Estimates of elemental abundance are difficult because (a) the composition of the upper and lower crust are quite different, and (b) the composition of the continental crust can vary drastically by locality. The composition of the Earth changed after its formation due to loss of volatile compounds, melting and recrystalization, selective loss of some elements to the deep in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
