A (simple) arc in finite projective geometry is a set of points which satisfies, in an intuitive way, a feature of curved figures in continuous geometries. Loosely speaking, they are sets of points that are far from "line-like" in a plane or far from "plane-like" in a three-dimensional space. In this finite setting it is typical to include the number of points in the set in the name, so these simple arcs are called k-arcs. An important generalization of the k-arc concept, also referred to as arcs in the literature, are the (k, d)-arcs.
In a finite projective plane π (not necessarily Desarguesian) a set A of k (k ≥ 3) points such that no three points of A are collinear (on a line) is called a k - arc. If the plane π has order q then k ≤ q + 2, however the maximum value of k can only be achieved if q is even. In a plane of order q, a (q + 1)-arc is called an oval and, if q is even, a (q + 2)-arc is called a hyperoval.
Every conic in the Desarguesian projective plane PG(2,q), i.e., the set of zeros of an irreducible homogeneous quadratic equation, is an oval. A celebrated result of Beniamino Segre states that when q is odd, every (q + 1)-arc in PG(2,q) is a conic. This is one of the pioneering results in finite geometry.
Arc, for activity-regulated cytoskeleton-associated protein (also known as Arg3.1), is a plasticity protein first characterized in 1995. Arc is a member of the immediate-early gene (IEG) family, a rapidly activated class of genes functionally defined by their ability to be transcribed in the presence of protein synthesis inhibitors. Arc mRNA is localized to activated synaptic sites in an NMDA receptor-dependent manner, where the newly translated protein is believed to play a critical role in learning and memory-related molecular processes. Arc is widely considered to be an important protein in neurobiology because of its activity regulation, localization, and utility as a marker for plastic changes in the brain. Dysfunctions in the production of Arc protein has been implicated as an important factor in understanding of various neurological conditions including: Amnesia;Alzheimer's disease; Autism spectrum disorders; and, Fragile X syndrome. Along with other IEGs such as zif268 and Homer 1a, Arc is also a significant tool for systems neuroscience as illustrated by the development of the cellular compartment analysis of temporal activity by fluorescence in situ hybridization, or catFISH technique (see fluorescent in situ hybridization).
In Euclidean geometry, an arc (symbol: ⌒) is a closed segment of a differentiable curve. A common example in the plane (a two-dimensional manifold), is a segment of a circle called a circular arc. In space, if the arc is part of a great circle (or great ellipse), it is called a great arc.
Every pair of distinct points on a circle determines two arcs. If the two points are not directly opposite each other, one of these arcs, the minor arc, will subtend an angle at the centre of the circle that is less than π radians (180 degrees), and the other arc, the major arc, will subtend an angle greater than π radians.
The length (more precisely, arc length), L, of an arc of a circle with radius and subtending an angle
(measured in radians) with the circle center — i.e., the central angle — equals
. This is because
Substituting in the circumference
and, with being the same angle measured in degrees, since
the arc length equals
A practical way to determine the length of an arc in a circle is to plot two lines from the arc's endpoints to the center of the circle, measure the angle where the two lines meet the center, then solve for L by cross-multiplying the statement:
Twisted may refer to:
Twisted (Usher and Pharrel song)
Laurie Halse Anderson (born October 23, 1961) is an American writer best known for children's and young adult novels. She received the Margaret A. Edwards Award from the American Library Association in 2009 for her contribution to young adult literature.
She was first recognized for her novel Speak, published in 1999.
Laurie Beth Halse was born to Rev. Frank A. Halse Jr. and Joyce Holcomb Halse in Potsdam, New York. She grew up there with her younger sister, Lisa. As a student, she showed an early interest in writing, specifically during the second grade. Anderson enjoyed reading—especially science fiction and fantasy—as a teenager, but never envisioned herself becoming a writer.
Anderson attended Fayetteville-Manlius High School, in Manlius, New York, a suburb of Syracuse.
During Anderson’s senior year, she moved out of her parents' house at the age of sixteen and lived as an exchange student for thirteen months on a pig farm in Denmark. After her experience in Denmark, Anderson moved back home to work at a clothing store, earning the minimum wage. This motivated her to attend college.
Twisted is a 1986 horror and psychological thriller starring Christian Slater, Lois Smith, and Tandy Cronyn.
One evening, the Collins family discovers their maid, Mrs. Murdock, dead at the end of their steps; her neck is broken. Evidently, she had an accident; now they need a new babysitter for an upcoming party. The sensible Helen meets little Susan Collins at the discount market and likes her, so she offers to do the job. She does not know Susan's teenage brother Mark: technically skilled and good in school, but restive and cunning. Mark also listens regularly to German marching music from the Third Reich. As soon as the parents have left, he psychologically terrorizes Helen and his sister with electronic tricks. Williams (Karl Taylor), a school jock whom Mark burned earlier in science class, is out for revenge; Mark murders him with a fencing sword.
Ultimately, Mark himself is killed when Helen knocks him onto a spiked German helmet. Mark's parents come home to find the house in shambles; they blame Helen and have her arrested, unaware that Mark lies dead upstairs. Secretly, Susan dons her late brother's glasses and proceeds to listen to his Nazi music and the cycle begins anew.
Pines are conifer trees in the genus Pinus /ˈpiːnuːs/, in the family Pinaceae. They are the only genus in the subfamily Pinoideae. The Plant List compiled by the Royal Botanic Gardens, Kew and Missouri Botanical Garden accepts 126 species names of pines as current, together with 35 unresolved species and many more synonyms.
The modern English name pine derives from Latin pinus which some have traced to the Indo-European base *pīt- ‘resin’ (source of English pituitary). In the past (pre-19th century) they were often known as fir, from Old Norse fura, by way of Middle English firre. The Old Norse name is still used for pines in some modern north European languages, in Danish fyr, in Norwegian fura/fure/furu, Swedish fura/furu, Dutch vuren, and Föhre in German, but in modern English, fir is now restricted to fir (Abies) and Douglas-fir (Pseudotsuga).
Pines are gymnosperms. The genus is divided into three subgenera, which can be distinguished by cone, seed, and leaf characters: