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Environmental factor

Apart from the true monogenicgenetic disorders, environmental factors may determine the development of disease in those genetically predisposed to a particular condition. Stress, physical and mentalabuse, diet, exposure to toxins, pathogens, radiation and chemicals found in almost all personal care products and household cleaners are common environmental factors that determine a large segment of non-hereditary disease. Environmental factors such as the weather affect business interests. If a disease process is concluded to be the result of a combination of genetic and environmental factor influences, its etiological origin can be referred to as having a multifactorial pattern.

An example of an environmental trigger would be a component of a human's drinking water which holds the possibility of activating (triggering) a change in a person's body. These changes are mainly negative ones. Using this example, what is in the drinking water may affect one person entirely different than another -- someone may be affected greatly, whereas someone may not be at all.

Many cancers (osteosarcoma, etc), along with a plethora of other diseases, are thought to be a result of environmental triggers.

Nitrates may be an environmental trigger for Alzheimer's, diabetes, and Parkinson's disease.

Environmental triggers for asthma and autism have been studied too.

Hypoxia (environmental)

Hypoxia, or oxygen depletion, is a phenomenon that occurs in aquatic environments as dissolved oxygen (DO; molecular oxygen dissolved in the water) becomes reduced in concentration to a point where it becomes detrimental to aquatic organisms living in the system. Dissolved oxygen is typically expressed as a percentage of the oxygen that would dissolve in the water at the prevailing temperature and salinity (both of which affect the solubility of oxygen in water; see oxygen saturation and underwater). An aquatic system lacking dissolved oxygen (0% saturation) is termed anaerobic, reducing, or anoxic; a system with low concentration—in the range between 1 and 30% saturation—is called hypoxic or dysoxic. Most fish cannot live below 30% saturation. A "healthy" aquatic environment should seldom experience less than 80%. The exaerobic zone is found at the boundary of anoxic and hypoxic zones.

Where hypoxia occurs

Hypoxia can occur throughout the water column and also at high altitudes as well as near sediments on the bottom. It usually extends throughout 20-50% of the water column, but depending on the water depth and location of pycnoclines (rapid changes in water density with depth) it can occur in 10-80% of the water column. For example, in a 10-meter water column, it can reach up to 2 meters below the surface. In a 20-meter water column, it can extend up to 6 meters below the surface.

Causes of hypoxia

Oxygen depletion can result from a number of natural factors, but is most often a concern as a consequence of pollution and eutrophication in which plant nutrients enter a river, lake, or ocean, and phytoplankton blooms are encouraged. While phytoplankton, through photosynthesis, will raise DO saturation during daylight hours, the dense population of a bloom reduces DO saturation during the night by respiration. When phytoplankton cells die, they sink towards the bottom and are decomposed by bacteria, a process that further reduces DO in the water column. If oxygen depletion progresses to hypoxia, fish kills can occur and invertebrates like worms and clams on the bottom may be killed as well.

Hypoxia may also occur in the absence of pollutants. In estuaries, for example, because freshwater flowing from a river into the sea is less dense than salt water, stratification in the water column can result. Vertical mixing between the water bodies is therefore reduced, restricting the supply of oxygen from the surface waters to the more saline bottom waters. The oxygen concentration in the bottom layer may then become low enough for hypoxia to occur. Areas particularly prone to this include shallow waters of semi-enclosed water bodies such as the Waddenzee or the Gulf of Mexico, where land run-off is substantial. In these areas a so-called "dead zone" can be created. The World Resources Institute has identified 375 hypoxic coastal zones around the world, concentrated in coastal areas in Western Europe, the Eastern and Southern coasts of the US, and East Asia, particularly in Japan.

Hypoxia may also be the explanation for periodic phenomena such as the Mobile Bay jubilee, where aquatic life suddenly rushes to the shallows, perhaps trying to escape oxygen-depleted water. Recent widespread shellfish kills near the coasts of Oregon and Washington are also blamed on cyclic dead zone ecology.


To combat hypoxia, it is essential to reduce the amount of land-derived nutrients reaching rivers in runoff. Defensively this can be done by improving sewage treatment and by reducing the amount of fertilizers leaching into the rivers. Offensively this can be done by restoring natural environments along a river; marshes are particularly effective in reducing the amount of phosphorus and nitrogen (nutrients) in water.

Technological solutions are also possible, such as that used in the redeveloped Salford Docks area of the Manchester Ship Canal in England, where years of runoff from sewers and roads had accumulated in the slow running waters. In 2001 a compressed air injection system was introduced, which raised the oxygen levels in the water by up to 300%. The resulting improvement in water quality led to an increase in the number of invertebrate species, such as freshwater shrimp, to more than 30. Spawning and growth rates of fish species such as roach and perch also increased to such an extent that they are now amongst the highest in England.

In a very short time the oxygen saturation can drop to zero when offshore blowing winds drive surface water out and anoxic depthwater rises up. At the same time a decline in temperature and a rise in salinity is observed (from the longterm ecological observatory in the seas at Kiel Fjord, Germany). New approaches of long-term monitoring of oxygen regime in the ocean observe online the behavior of fish and zooplankton, which changes drastically under reduced oxygen saturations (ecoSCOPE) and already at very low levels of water pollution.

Bog chemistry

In certain northern European sphagnum acidic bogs, a condition of hypoxia arises that prevents tissue decay by impeding micro-organisms in th

Algorithm examples

This article 'Algorithm examples supplementsAlgorithm and Algorithm characterizations.

An example: Algorithm specification of addition m+n

Choice of machine model:

There is no “best�, or “preferred� model. The Turing machine, while considered the standard, is notoriously awkward to use. And different problems seem to require different models to study them. Many researchers have observed these problems, for example:

“The principal purpose of this paper is to offer a theory which is closely related to Turing's but is more economical in the basic operations� (Wang (1954) p. 63)
“Certain features of Turing machines have induced later workers to propose alternative devices as embodiments of what is to be meant by effective computability.... a Turing machine has a certain opacity, its workings are known rather than seen. Further a Turing machine is inflexible ... a Turing machine is slow in (hypothetical) operation and, usually complicated. This makes it rather hard to design it, and even harder to investigate such matters as time or storage optimization or a comparison between efficiency of two algorithms.� (Melzak (1961) p. 281)
Shepherdson-Sturgis (1963) proposed their register-machine model because “these proofs [using Turing machines] are complicated and tedious to follow for two reasons: (1) A Turing machine has only one head... (2) It has only one tape....� They were in search of “a form of idealized computer which is sufficiently flexible for one to be able to convert an intuitive computational procedure into a program for such a machine� (p. 218).
“I would prefer something along the lines of the random access computers of Angluin and Valiant [as opposed to the pointer machine of Schönhage]� (Gurivich 1988 p. 6)
“Showing that a function is Turing computable directly...is rather laborious ... we introduce an ostensibly more flexible kind of idealized machine, an abacus machine...� (Boolos-Burgess-Jeffrey 2002 p.45).

About all that one can insist upon is that the algorithm-writer specify in exacting detail (i) the machine model to be used and (ii) its instruction set.

Atomization of the instruction set:

The Turing machine model is primitive, but not as primitive as it can be. As noted in the above quotes this is a source of concern when studying complexity and equivalence of algorithms. Although the observations quoted below concern the Random access machine model – a Turing-machine equivalent – the problem remains for any Turing-equivalent model:

“...there hardly exists such a thing as an ‘innocent’ extension of the standard RAM model in the uniform time measure; either one only has additive arithmetic, or one might as well include all multiplicative and/or bitwise Boolean instructions on small operands....� (van Emde Boas (1992) p. 26)
“Since, however, the computational power of a RAM model seems to depend rather sensitively on the scope of its instruction set, we nevertheless will have to go into detail...
“One important principle will be to admit only such instructions which can be said to be of an atomistic nature. We will describe two versions of the so-called successor RAM, with the successor function as the only arithmetic operation....the RAM0 version deserves special attention for its extreme simplicity; its instruction set consists of only a few one letter codes, without any (explicit) addressing.� (Schönhage (1980) p.494)

Example #1: The most general (and original) Turing machine – single-tape with left-end, multi-symbols, 5-tuple instruction format – can be atomized into the Turing machine of Boolos-Burgess-Jeffrey (2002) – single-tape with no ends, two "symbols" { B, | } (where B symbolizes "blank square" and | symbolizes "marked square"), and a 4-tuple instruction format. This model in turn can be further atomized into a Post-Turing machine– single-tape with no ends, two symbols { B, | }, and a 0- and 1-parameter instruction set ( e.g. { Left, Right, Mark, Erase, Jump-if-marked to instruction xxx, Jump-if-blank to instruction xxx, Halt } ).

Example #2: The RASP can be reduced to a RAM by moving its instructions off the tape and (perhaps with translation) into its finite-state machine “table� of instructions, the RAM stripped of its indirect instruction and reduced to a 2- and 3-operand “abacus� register machine; the abacus in turn can be reduced to the 1- and 2-operand Minsky (1967)/Shepherdson-Sturgis (1963) counter machine, which can be further atomized into the 0- and 1-operand instructions of Schönhage (and even a 0-operand Schönhage-like instruction set is possible).

Cost of atomization:

Atomization comes at a (usually severe) cost: while the resulting instructions may be “simpler�, atomization (usually) creates more instructions and the need for more computational steps. As shown in the following example the increase in computation steps may be significant (i.e. orders of magnitude – the following example is “tame�), and atomization may (but not always, as in the case of the Post-Turing model) reduce the usability and readability of “the machine code�. For more see Turing tarpit.

Example: The single register machine instruction "INC 3" – increment the contents of register #3, i.e. increase its count by 1 – can be atomized into the 0-parameter instruction set of Schönhage, but with the equivalent number of steps to accomplish the task increasing to 7; this number is directly related to the register number “n� i.e. 4+n):

More examples can be found at the pages Register machine and Random access machine where the addition of "convenience instructions" CLR h and COPY h1,h1 are shown to reduce the number of steps dramatically. Indirect addressing is the other significant example.

Precise specification of Turing-machine algorithm m+n

As described in Algorithm characterizations per the specifications of Boolos-Burgess-Jeffrey (2002) and Sipser (2006), and with a nod to the other characterizations we proceed to specify:

(i) Number format: unary strings of marked squares (a "marked square" signfied by the symbol 1) separated by single blanks (signified by the symbol B) e.g. “2,3� = B11B111B
(ii) Machine type: Turing machine: single-tape left-ended or no-ended, 2-symbol { B, 1 }, 4-tuple instruction format.
(iii) Head location: See more at “Implementation Description� below. A symbolic representation of the head's location in the tape's symbol string will put the current state to the right of the scanned symbol. Blank squares may be included in this protocol. The state's number will appear with brackets around it, or sub-scripted. The head is shown as

From Yahoo Answers

Question:Is it possible to have "Focal Abnormalities at the ankle joint of the mid tarsal area. with findings suggesting artthritic or traumatic changes" as a result of 7 months of limping on that foot? I injured myself at work in sept of 07' and they still have no idea whats wrong. I "sprained" my left ankle and have been in a boot almost 7 months because I have no rotation and still excesive pain and swelling. I had a bone scan recently which showed my injured foot as normal, but my good foot showed the aboved quoted findings. Now the insc company wants to challenge coverage because it is not "compensible with injury". My "good" leg is becoming painful and hard to limp around anymore and I was just curious is this might be the reason... Any advice? Its workmens comp related...

Answers:"focal abnormalities" sounds like 'overused and bruised' to me. It's almost imperative that when you injure one ankle that you'd be riding in wheel chairs to alleviate pressure on both the ankles. it's called compensatory damage, because the other side usually gets worse, as it is in your case. (For example, when you injure an eye, they cover both your eyes to prevent any unwanted changes to your eyesight) I find it hard to believe that your doctor let you limp around for 7 months on one ankle! Crunches are always recommend to be paired (to prevent damage to the other leg) and canes are recommended to be used on the opposite side of the injured leg to aid the helping leg (non-injured). I do not know what the worker's comp policy is on that but one must always take care of the other leg just as much as the injured one in such cases. i wish you all the best. Sorry if I couldn't be of help that much.

Question:There are many materials that lend themselves to recycling. Some of these do not have the clear-cut, easily seen advantage of aluminum recycling. For example, to make glass from raw materials requires a little over 18,100 kJ/kg of glass manufactured. To make glass from recycled materials takes about 16,700 kJ/kg of glass product. If the costs of collecting the recycled glass are factored in, the energy savings are more than offset. 9) Cite two environmental and two economic reasons to manufacture glass from recycled materials, even if the costs are higher than using raw materials.

Answers:huh? You totally lost me. sorry

Question:a. the production of plans bearing oval squash from parents plants bearing round and long squash b. the effect of light on chlorophyll production in plants c. the pattern of inheritance for sex linked traits in humans d. the production of human offspring with blood type AB A change which affects the base sequence in the DNA of an organism may result in a. synthesis b. mutation c. replication 4. adaptive radiation thanks in advance!

Answers:b. the effect of light on chlorophyll production in plants 4. adaptive radiation The wording of the second question seems to exclude choice b, mutation, since a mutation is a change which affects the base sequence, and the question asks what a possible result of that change is, not what the definition of that change is.

Question:Hey everyone, My teacher said he would be talking about ACID RAIN in class in the following days, and have us create some kind of awareness about it in our community. I just wanted some background information about it, and your perspective upon that matter. Of course i can read various texts about it, but i want to know what you guys think about it, and if it is something to be taken seriously? Also, if anyone has any ideas of how to spread awareness about the harmful effects of acid rain, please let me know...because not only would it help me, but also be easier to spread the word. (Include examples of why it's bad, instead of just saying, "It's bad!!!" pleasseee!) Thanks, Take Care

Answers:acid rain causes corrosion on limestone, rock and metals over years. acid rain is caused because of too much pollution going into the atmosphere

From Youtube

3D Scan of Female Model :Example of 3D Scan of a Female full body scan. We first show the geometry followed by the re-topologizing of the model with quads to make animation ready. We then added UV's texture map and touched up in Zbrush for the final look.

Mass Effect 2 46 - Mineral Scanning (Boring) :This is one of my boring vids, but at least I want to give an example of what this game is like. This is Mass Effects new minigame. You basically go to many planets scanning for 4 types of minerals. Each type is used for upgrades in specific categories. Platinum and Element Zero are the rarest to get. EZ is rarer, but you don't need that much.. which leaves Platinum to be the thing that you always want more. The other 2 are quite common. The graph indicates if an element is obtained if you were to use a pod. Pods cost money to use, to use them wisely. Besides elements, we also get anomalies, which are sidequest missions. I think I want to annotate this vid, but it's under consideration