Poll (livestock)

The poll is a name of the part of an animal's head, alternatively referencing a point immediately behind or right between the ears. This area of the anatomy is of particular significance for the horse.

Specifically, the "poll" refers to the occipital protrusion at the back of the skull. However, in common usage, many horsemen refer to the poll joint, between the atlas (C1) and skull as the poll. The area at the joint has a slight depression, and is a sensitive location. Thus, because the crownpiece of a bridle passes over the poll joint, a rider can indirectly exert pressure on the horse's poll by means of the reins, bit, and bridle.

Importance of the poll in riding

The poll is especially important in riding, as correct flexion at the poll joint is a sign that the horse is properly on the bit. Over-flexion, with the poll lowered and the neck bent at a cervical vertebra farther down the neck, is usually a sign that the horse is either evading contact or that the rider is trying to pull the horse onto the bit, rather than correctly ride from behind. In classical dressage, the poll should always be the highest point on the horse when the horse is on the bit. The horse is always relaxed over the poll, giving it a relaxed look when going about its job. When, for example, the third vertebra (C3) is the highest point on the neck, rather than the poll, it is a clear sign of incorrect work.

DNA polymerase lambda

DNA polymerase lambda, also known as POLL, is a protein that, in humans, is encoded by the POLLA gene.

Function

Pol λ is a member of the X family of DNA polymerases. It is thought to resynthesize missing nucleotides during non-homologous end joining, a pathway of DNA double-strand break repair. The crystal structure of pol λ shows that, unlike the DNA polymerases that catalyze DNA replication, pol λ makes extensive contacts with the 5' phosphate of the downstream DNA strand. This allows the polymerase to stabilize the two ends of a double-strand break and explains how pol λ is uniquely suited for a role in non-homologous end joining. In addition to NHEJ, pol λ can also participate in base excision repair, where it provides backup activity in the absence of Pol β.

Besides its catalytic polymerase domain, pol λ has an 8 kDa domain and a BRCT domain. The 8 kDa domain has lyase activity that can remove a 5' deoxyribosephosphate group from the end of a strand break. The BRCT domain is a phosphopeptide binding domain that is common among DNA repair proteins and is likely involved in coordinating protein-protein interactions. Pol λ is structurally and functionally related to pol μ, another member of the X family that also participates in non-homologous end joining. Like pol μ, pol λ participates in V(D)J recombination, the process by which B-cell and T-cell receptor diversity is generated in the vertebrate immune system. Whereas pol μ is important for heavy-chain rearrangements, pol λ seems to be more important for light-chain rearrangements. The yeast Saccharomyces cerevisiae has a single homolog of both pol λ and pol μ called Pol4.

Horse

The horse (Equus ferus caballus) is one of two extant subspecies of Equus ferus. It is an odd-toed ungulate mammal belonging to the taxonomic family Equidae. The horse has evolved over the past 45 to 55 million years from a small multi-toed creature, Hyracotherium, into the large, single-toed animal of today. Humans began to domesticate horses around 4000 BC, and their domestication is believed to have been widespread by 3000 BC. Horses in the subspecies caballus are domesticated, although some domesticated populations live in the wild as feral horses. These feral populations are not true wild horses, as this term is used to describe horses that have never been domesticated, such as the endangered Przewalski's horse, a separate subspecies, and the only remaining true wild horse. There is an extensive, specialized vocabulary used to describe equine-related concepts, covering everything from anatomy to life stages, size, colors, markings, breeds, locomotion, and behavior.

Horses' anatomy enables them to make use of speed to escape predators and they have a well-developed sense of balance and a strong fight-or-flight response. Related to this need to flee from predators in the wild is an unusual trait: horses are able to sleep both standing up and lying down. Female horses, called mares, carry their young for approximately 11 months, and a young horse, called a foal, can stand and run shortly following birth. Most domesticated horses begin training under saddle or in harness between the ages of two and four. They reach full adult development by age five, and have an average lifespan of between 25 and 30 years.

Horse (disambiguation)

A horse is a hoofed mammal of the species Equus ferus caballus.

Horse or Horses may also refer to:

Animals

Arts and entertainment

Horse (1941 film)

Uma (馬, also known as Horse) is a 1941 black-and-white Japanese film directed by Kajiro Yamamoto and starring Hideko Takamine, whom Yamamoto had directed in his film Composition Class (Tsuzurikata Kyōshitsu) three years before. Uma was actually completed by assistant director Akira Kurosawa. It follows the story of Ine Onoda, the eldest daughter of a poor family of farmers, who raises a colt from birth and comes to love the horse dearly. When the horse is grown, the government orders it auctioned and sold to the army. Ine struggles to prevent the sale.

Overview

The film is a tale about a young girl and the colt she raises from its birth. But it is also about the struggle of farmers existing on the edge of poverty. Akira Kurosawa is credited as the film's production coordinator, which is equivalent to first assistant director. But Kurosawa's signature is all over this work and is the last film he was to work on as an assistant before starting his own directing career. The film took three years to plan and a year to film. Kajiro Yamamoto had to commute to the far mountainous location but had to turn his attention to his money making comedies in Tokyo and so he left production in the hands of his assistant, Kurosawa.