SUMMARY / RELATED TOPICS

Bird migration

Bird migration is the regular seasonal movement north and south along a flyway, between breeding and wintering grounds. Many species of bird migrate. Migration carries high costs in predation and mortality, including from hunting by humans, is driven by availability of food, it occurs in the northern hemisphere, where birds are funneled on to specific routes by natural barriers such as the Mediterranean Sea or the Caribbean Sea. Migration of species such as storks, turtle doves, swallows was recorded as many as 3,000 years ago by Ancient Greek authors, including Homer and Aristotle, in the Book of Job. More Johannes Leche began recording dates of arrivals of spring migrants in Finland in 1749, modern scientific studies have used techniques including bird ringing and satellite tracking to trace migrants. Threats to migratory birds have grown with habitat destruction of stopover and wintering sites, as well as structures such as power lines and wind farms; the Arctic tern holds the long-distance migration record for birds, travelling between Arctic breeding grounds and the Antarctic each year.

Some species of tubenoses such as albatrosses circle the earth, flying over the southern oceans, while others such as Manx shearwaters migrate 14,000 km between their northern breeding grounds and the southern ocean. Shorter migrations are common, including altitudinal migrations on mountains such as the Andes and Himalayas; the timing of migration seems to be controlled by changes in day length. Migrating birds navigate using celestial cues from the sun and stars, the earth's magnetic field, mental maps. In the Pacific, traditional landfinding techniques used by Micronesians and Polynesians suggest that bird migration was observed and interpreted for more than 3000 years. In Samoan tradition, for example, Tagaloa sent his daughter Sina to Earth in the form of a bird, Tuli, to find dry land, the word tuli referring to landfinding waders to the Pacific golden plover. Records of bird migration were known in Europe from at least 3,000 years ago as indicated by the Ancient Greek writers Hesiod, Homer and Aristotle.

The Bible notes migrations, as in the Book of Job, where the inquiry is made: "Is it by your insight that the hawk hovers, spreads its wings southward?" The author of Jeremiah wrote: "Even the stork in the heavens know its seasons, the turtle dove, the swift and the crane keep the time of their arrival." Aristotle noted that cranes traveled from the steppes of Scythia to marshes at the headwaters of the Nile. Pliny the Elder, in his Historia Naturalis, repeats Aristotle's observations. Aristotle, suggested that swallows and other birds hibernated; this belief persisted as late as 1878, when Elliott Coues listed the titles of no less than 182 papers dealing with the hibernation of swallows. The "highly observant" Gilbert White, in his posthumously published 1789 The Natural History of Selborne, quoted a man's story about swallows being found in a chalk cliff collapse "while he was a schoolboy at Brighthelmstone", though the man denied being an eyewitness. However, he writes that "as to swallows being found in a torpid state during the winter in the Isle of Wight or any part of this country, I never heard any such account worth attending to", that if early swallows "happen to find frost and snow they withdraw for a time—a circumstance this much more in favour of hiding than migration", since he doubts they would "return for a week or two to warmer latitudes".

It was not until the end of the eighteenth century that migration as an explanation for the winter disappearance of birds from northern climes was accepted. Thomas Bewick's A History of British Birds mentions a report from "a intelligent master of a vessel" who, "between the islands of Menorca and Majorca, saw great numbers of Swallows flying northward", states the situation in Britain as follows: Swallows roost at night, after they begin to congregate, by the sides of rivers and pools, from which circumstance it has been erroneously supposed that they retire into the water. Bewick describes an experiment which succeeded in keeping swallows alive in Britain for several years, where they remained warm and dry through the winters, he concludes: These experiments have since been amply confirmed by... M. Natterer, of Vienna... and the result proves, what is in fact now admitted on all hands, that Swallows do not in any material instance differ from other birds in their nature and propensities.

In 1822, a white stork was found in the German state of Mecklenburg with an arrow made from central African hardwood, which provided some of the earliest evidence of long-distance stork migration. This bird was referred to as a Pfeilstorch, German for "Arrow stork". Since around 25 Pfeilstörche have been documented. Migration is the regular seasonal movement north and south, undertaken by many species of birds. Bird movements include those made in response to changes in habitat, or weather. Sometimes, journeys are not termed "true migration" because they are irregular or in only one direction. Migration is marked by its annual seasonality. Non-migratory birds are said to be sedentary. 1800 of the world's 10,000 bird species are long-distance migrants. Many bird populations migrate long distances along a flyway; the most common pattern involves flying north in the spring to breed in the temperate or Arctic summer and returning in the autumn

Allochiria

Allochiria is a neurological disorder in which the patient responds to stimuli presented to one side of their body as if the stimuli had been presented at the opposite side. It is associated with spatial transpositions symmetrical, of stimuli from one side of the body to the opposite one, thus a touch to the left side of the body will be reported as a touch to the right side, known as somatosensory allochiria. If the auditory or visual senses are affected, sounds will be reported as being heard on the opposite side to that on which they occur and objects presented visually will be reported as having been presented on the opposite side. Patients may express allochiria in their drawing while copying an image. Allochiria co-occurs with unilateral neglect and, like hemispatial neglect, the disorder arises from damage to the right parietal lobe. Allochiria is confused with alloesthesia known as false allochiria. True allochiria is a symptom of dyschiria and unilateral neglect. Dyschiria is a disorder in the localization of sensation due to various degrees of dissociation and cause impairment in one side causing the inability to tell which side of the body was touched.

The term is from the Greek meaning "other hand". Allochiria has been observed in the context of neglect, due to a lesion that affects the right parietal lobe. In patients with allochiria, their sensibility is retained but the patient is not clear as to which side of the body has been touched, their power of localization is retained but error exists to the side touched and they refer the irritation to the corresponding part of the limb. In the patients' mind there is error as to which side of the body is touched. There are multiple definitions of allochiria. According to Musser, allochiria is the reference of a sensory stimulus to the corresponding location on the opposite location on the opposite side of the body. Judson Bury says that a patient may refer to an impression on one side to a corresponding place on the opposite side of the body. Thus, if a patient is pricked on one limb, he may say. Overall though different author's definition differs on points such as the type of stimulus, the symmetry between the site of the stimulus and the seat of its localization, they all agree that an essential feature of allochiria is the deflection of a sensation to the wrong side of the body, true allochiria.

In none of these definitions is any stress laid on the state of the patient's knowledge of a right or left side and the symptoms are seen as an error in localization. Obsersteiner laid stress that there is in allochiria no defect in vertical localization but confusion in the patient's mind between the opposite sides of the body and come to look upon the symptom as any form of bad mistake in localization. There is in the patient's mind doubt or error as to the side touched while sensibility including the power of localization is otherwise retained. Allochiria has been described as occurring in nerve lesions, disseminated sclerosis Multiple sclerosis, tabes dorsalis, unilateral injury to the spinal cord, Ménière's disease, symmetrical gangrene, in connection with touch, the "muscle sense," the temperature sense, smell, taste and the electrical reactions. Allochiria can occur in relation to every segment of the body. In some cases allochiria may be bilateral, in others it may be restricted to certain regions of the body, or only to one part of the body.

Allochiria is marked to have connections with a variety of senses and sometimes only certain kinds of stimuli can arouse the appropriate feeling of one sidedness. This is seen. Electromotor allochiria has been observed in the face, lower limbs, upper limbs. In these cases, a stimulus presented on the affected side caused contraction of the opposite facial muscles with a current so weak that the healthy facial did not react. Another example is; the central fact is that an electrical stimulus may manifest its effect at a distant part of the nervous system. This distant part may be on the same side of the body or on the opposite side it is more on the opposite side because the representation of corresponding contralateral limbs in the spinal cord are nearer to each other than homolateral limbs; this has nothing to do with the confusion of the two sides that occurs in the patients mind when allochiria is present. If patient asked to carry out a movement on effect side he does so with the corresponding part of the opposite side under the impression that he has performed the required movement.

Patients with reflex allochiria respond to a stimulation of the sole of the foot or in the inner part of the thigh as being evoked as the corresponding reflex on the opposite side only. In cases of auditory allochiria, observations recorded that when a tuning fork was held to one ear, the patient responded with a series of symptoms, including pain and deafness, in the opposite ear. In visual allochiria, objects situated on one side of the visual field are perceived in the contralateral visual field. In one of the two cases recorded, the visual impression received by the right open eye was referred to the left eye, the patient maintained that she perceived the impression with the left eye that in fact was shut. In the other case, a colored object held in front of the left eye was recognized and the patient maintained that she saw the color with the right eye. In a case of gustatory allochiria, a substance p

Gamma 3

Gamma 3 is Gamma's third album, released in 1982. "What's Gone Is Gone" - 5:30 "Right the First Time" - 3:47 "Moving Violation" - 3:36 "Mobile Devotion" - 6:34 "Stranger" - 3:00 "Condition Yellow" - 4:08 "Modern Girl" - 3:35 "No Way Out" - 4:05 "Third Degree" - 3:47 Davey Pattison: vocals Ronnie Montrose: guitar Mitchell Froom: keyboards Glenn Letsch: bass guitar Denny Carmassi: drums Produced by Ronnie Montrose Engineered by Jim Gaines Gamma.