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Monday, November 14, 2016

The Biological Activated Carbon Process for Water Purification

Water Treatment
Granular activated carbon (GAC) has been used extensively for the removal of dissolved organics from drinking water. In the early seventies, it was reported that bacteria which proliferate in GAC filters may be responsible for a fraction of the net removal of organics in the filter. Following this discovery, pre-ozonation was found to significantly enhance the biological activity on GAC. The combination of ozonation and GAC is commonly referred to as the biological activated carbon (BAC) process, or biologically enhanced activated carbon process.
In Europe, the BAC process was implemented in many large water treatment plants in the '80s. Reasons for its widespread use include
  • The generally poorer quality of surface waters, when compared to North America
  • The concern for chlorination by-products. For instance, under the European Community drinking water directives, the guide level for organochlorine compounds is 1 µg/L
  • The strict aesthetic demands of European consumers.
The European way of thinking for production of high quality drinking water is spreading rapidly in other industrialized countries such as Japan, Canada, and Australia.The US water industry has been reluctant to use microorganisms for drinking water treatment. However, biological treatment is expected to become more common over the next decade. Driving forces behind this change will be the increased use of ozone in response to the disinfectants-disinfection by-product (D-DBP) rule, and the increased concern over biological regrowth in the distribution system.
Benefits of Biological Activity
Biological elimination of dissolved organic compounds within GAC filters offers several finished water quality benefits. For instance, biological activity removes a significant fraction of dissolved organic carbon (DOC). A theoretical representation of DOC removed by adsorption and biological activity is shown in the figure. Initially, most of the removal occurs through physical adsorption (Period A), while the bacteria are in the acclimation phase. During this period, DOC removal ranges from 40 to 90 percent. A 10 to 20 percent fraction is nonadsorbable on GAC .
During period B, adsorption and biological degradation processes operate in parallel. The bacteria are now acclimated, and the removal by adsorption is gradually decreasing due to the saturation of adsorption sites. Period C is referred to as the steady-state period. Biological oxidation is the predominant process responsible for DOC removal. Most of the adsorption capacity is exhausted. Under steady-state conditions, DOC removal efficiencies range from 15 to 40 percent. If the removal efficiency obtained under steady-state conditions meets treatment objectives, the service life of GAC can be significantly increased.
Naturally occurring compounds comprising the DOC of surface waters are known to be precursors of disinfection (chlorination) by-products (DBPs) such as trihalomethanes (THMs) and haloacetic acids (HAAs). THMs and HAAs are the major compounds targeted under the D-DBP rule. The removal of these DBP precursors correlates with the removal of DOC. However, greater removal efficiencies have been reported for precursors of total organic halogen (TOX), THM and HAA than for DOC, showing the selectivity of biological treatment for these chlorine-reactive compounds. Under steady-state conditions, removal efficiencies of THM and HAA precursors reportedly range from 20 to 70 percent. Removal efficiencies are much greater in the initial stages of the process (Period A), in which 75 to 90 percent of precursors are removed through physical adsorption.
Biological oxidation within GAC filters also can be efficient for the removal of inorganics such as ammonia. Ammonia is a toxic chemical which promotes biogrowth and reacts with chlorine. The combined removal of DOC and ammonia leads to a significant reduction of the chlorine demand of the finished water. A reduced chlorine demand lowers the amount of DBPs and improves the aesthetic quality of the water.
Pre-ozonation provides many benefits to the water treatment process (e.g., excellent disinfection without the formation of THMs or HAAs, microflocculation, color removal, iron and manganese removal, reduction of taste and odor, enhanced biological activity, etc.). However, ozonation by-products are generally readily biodegradable and can lead to biogrowth in the distribution system. The removal of these biodegradable compounds within BAC filters leads to the control of biological regrowth and an increased stability of the residual chlorine. Under steady-state conditions, removal efficiencies of assimilable organic carbon (AOC) and biodegradable organic carbon (BDOC) have been reported to range from 50 to 100 percent. In addition, the process can lead to the complete removal of ozonation by-products that are of health concern and may be targeted for future regulations. These include some short-chain aldehydes.
Biologically active GAC also can be effective for eliminating synthetic organic chemicals such as benzene, toluene, and pesticides like atrazine which present health concerns. The process also can reduce the concentrations of taste- and odor-causing compounds such as short-chain aldehydes (fruity), amines and aliphatic aldehydes (fishy), and phenols and chlorinated phenols (antiseptic/medicinal).
Finally, biological activity can enhance the adsorption capacity of GAC for non- or slowly biodegradable compounds by eliminating substances that would otherwise compete for adsorption sites. This is sometimes referred to as the bioregeneration effect.
Major BAC Process Variables
The empty bed contact time is the most important parameter for the removal of biodegradable organic matter. The contact time to be selected is dependent on the treatment objective, the support media type (discussed later), and the water temperature. Contact times reported in major French waterworks range from 10 to 15 minutes. Efficient AOC removal can be obtained with a contact time less than five minutes.
The presence of microorganisms and higher forms of life in BAC filters leads to more rapid pressure buildups and requires more frequent and efficient backwashing procedures. The effect is more drastic in warm water than in cold water. BAC filters must be backwashed on a regular basis to prevent the proliferation of higher organisms in the media and maintain a low trophic level. A fraction of the bacterial biomass fixed on GAC is eliminated during backwashing. In cold water, the removal efficiency of biodegradable matter is significantly reduced after backwashing, but winter operation requires less frequent backwashing. This reduction is even more significant if filters are backwashed with chlorinated water. Additionally, the efficiency of biological treatment is lowered if the influent has been predisinfected with chlorine, chloramines, or chlorine dioxide.
Recent Canadian and US studies have demonstrated that first stage BAC filters achieved similar performance to post-filter GAC adsorbers, drastically reducing the capital cost involved. Consequently, given an adequate contact time, BAC filters can be retrofitted into existing sand or dual media filters.
The risk of exportation of bacterial biomass into the effluent must be assessed when considering the BAC process. Bacteria exiting the BAC filters are easily eliminated by post-disinfection. Activated carbon particles have been shown to provide a habitat for organisms and to protect them from inactivation during postdisinfection. Additional filtration through sand is recommended to prevent escape of activated carbon fines in the product water. This can be accomplished by having a layer of sand media (6 to 9 in.) as a support for the granulated activated carbon media.
Biological Activity on Filtration Media
The efficiency of activated carbon for biological treatment of drinking water is significantly greater than the efficiency of conventional filtration media such as sand or anthracite.
Granular activated carbon has the ability to support a denser bacterial population than sand or anthracite. Under drinking water conditions and with preozonated water, fixed bacterial biomass reported in the literature ranges from 1.0X106 to 1.0X107 bacteria/gram of sand or anthracite versus 1.0X108 to 1.0X109 bacteria/gram of activated carbon.
Three major properties of GAC have been suggested to explain the differences.
  1. Porosity, surface area, and surface roughness: The average diameters of single-celled bacteria found in water supplies range from 0.3 to 10 µm. Activated carbon is characterized by the presence of man-made and inherent crevices, ridges, macro-pores, and other surface irregularities which provide a sheltered environment for colonization and protection from fluid shear forces.
  2. Adsorption capacity: The adsorptive capacity serves to
  • n Concentrate substances, including the substrates, nutrients and oxygen, on the surface of the carbon. This concentration effect promotes more rapid colonization and allows degradation to occur even when the substrate concentrations in the influent are too low to support growth.
  • Extend the contact time between the biomass and adsorbed organic substances.
  • Adsorb bacteria-adsorption of bacteria was found to agree with the Langmuir isotherm.
  • Reduce the concentration of toxic compounds in local microbial environments.
  1. Surface charge of activated carbon: The presence of a variety of functional groups on the carbon surface has been shown to enhance microbial attachment. Greater biological activity within and faster colonization on GAC lead to the following benefits over conventional filtration media:
  • Greater efficiency for the removal of biodegradable compounds. A similar performance will require a significantly longer time with sand and anthracite.
  • Shorter acclimation time. This has a major impact during start-up and after backwashing.
  • Faster response to variations in the influent water quality, such as concentration in biodegradable compounds, concentration in toxic organics, and temperature. Benefits are more pronounced in cold water.
  • Finally, physical adsorption on GAC provides additional benefits over conventional filtration media.
Selection of GAC for Biological Treatment
Factors to be considered when selecting activated carbon for the treatment of drinking water are:
  • Biological support properties
  • Adsorption capacity properties
  • Physical properties such as density, abrasion resistance, and hardness, and their effect on a reactivated product.
Biological Support Properties
Due to their inherent and/or man-made macroporous structure, adsorption capacity, and surface chemistry, most commercially available granular activated carbons are excellent support media for biological treatment of drinking water. Under water treatment conditions, similar performance has been obtained for the biological removal of dissolved organics with various activated carbons made from sources such as coal, lignite, and wood. Minor differences in performance have been shown in cold water.
Adsorption Properties
Adsorption capacity for dissolved organics is another critical property to consider. Total adsorption capacity, as expressed by the iodine number, and trace removal capacity, is important:
  • During start-up, after backwashing, and in response to variations in influent composition (the adsorption capacity of activated carbon serves to maintain effluent quality until the biological activity of the system is established.)
  • For the removal of non- or slowly biodegradable organics of concern (taste and odor compounds, micro-pollutants such as synthetic organic chemicals, pesticides, etc.)
  • For additional removal of natural organic matter.
Physical Properties
Additional properties to consider when selecting an activated carbon product include the apparent bed density (AD), hardness and abrasion resistance, chemical reactivity, ash level and ash constituents. These properties are characteristic limitations of the starting material (e.g., bituminous coal, lignite, wood, etc.).
The AD of activated carbon influences the backwashing efficiency, the thermal reactivation yield, and the quantity of product, on a weight basis, per volume of GAC contactor. Carbons characterized by a greater AD hold up to higher backwashing water velocities; they allow more flexibility for thermal reactivation; they represent a greater amount of product, on a weight basis, per bed volume (consequently, a longer on-stream time for a similar adsorption capacity). Finally, they hold up better to the removal of carbon atoms when contacted with oxidants such as chlorine or ozone.
Carbons with high hardness and abrasion resistance lead to low carbon losses (e.g., carbon fines) during treatment, backwashing, transfer, and thermal reactivation (high reactivation yields).
Low chemical reactivity products are critical for high thermal reactivation yields, and consequently lower make-up requirements and costs.
Finally, the ash content and ash constituents determine the leaching characteristics of the product.
Service Life
Several factors must be assessed when considering carbon changeout or reactivation. The most critical is the remaining adsorption capacity of the carbon. Significant capacity is required if an important fraction of DOC, and consequently of DBP precursors, must be removed. Under these conditions, the GAC service life ranges from six to 12 months.
Adsorption capacity also may be required for the control of taste and odor. For this purpose, service lives of two to five years can be expected.
Finally, the adsorption capacity will be required if the water contains the continuous or episodic presence of micropollutants such as synthetic organic chemicals, pesticides, etc. Carbon service lives of one to two years are common under these conditions. However, monitoring breakthrough of the contaminants may be needed for better predictions.
For high quality raw water, for which small reductions in DOC and DBP precursors are sufficient to meet the treatment objectives, and that do not contain micropollutants of concern or taste- and odor-causing compounds, biological activity on to GAC may suffice and significant physical adsorption may not be required. Under these conditions, the service life of the carbon may be limited by the buildup of metals and refractory organics on the carbon that would significantly reduce biological activity. Finally, metals buildup and high organic loadings will have a negative effect on the quality of the carbon and subsequent reactivated product if reactivation is used. For all these reasons, service lives of two to five years are recommended.
Thanks  http://www.wwdmag.com

Seven innovations that could shape the future of computing

In-memory computing
Graphene-based microchips


Quantum computing
Molecular electronics
DNA data storage
Neuromorphic computing
Passive Wi-fi.

Sunday, November 13, 2016

Garbarakshambigai Slokam to get pregnant


Women with infertility problems and others who are trying to conceive should read the following Mantra of Garbarakshambigai .
If time permits chant the Mantra 108 times everyday and invoke the blessings of the Goddess to get a healthy child.
Aum Garbarakshambigaayai cha vidhmahe
Mangala dhevadhaayai cha dheemahee
Dhanno devi prachodhayaath

There is also one more Slokam that can be chanted 108 times a day to get pregnant or to get married.
Aum devendhiraani namosthubyam
Dhevendhira piriya baamini
Vivaaha baakyam aarokyam
Puthra Laabam sadhehime
Padhim dhehi sudham dhehi
Soubaakyam dhehime subhe
Soumaangalyam subam Gnayanam
Dhehime Garbarakshake
Kaathyaayini mahaamaaye. Maha yoginya dhisvari
Nandhagoba seedham dhevam. Padhim Megurudhe Namah

May God shower her blessings on us with a healthy and long life child.

Thursday, November 10, 2016

The Graduate Movie


Based on the novel of the same name by Charles Webb, The Graduate is a 1967 comedy drama directed by Mike Nichols and starring Dustin Hoffman, Anne Bancroft, Katharine Ross and Murray Hamilton.
Benjamin Braddock (Hoffman) is twenty-one, has just graduated and finds himself mentally adrift and aimless as he is trying to shut out his parents' and society's advice on how to approach his future. At a graduation party thrown by his parents, he finds him self-driving his  father's law partner's wife, Mrs Robinson (Bancroft) home, where she proceeds to seduce him. Benjamin initially rebuffs her but it doesn't take long for him to change his mind as he starts an affair with the older woman. Things complicate significantly, though, when Mr. Robinson (Hamilton) and his parents set him  up with the Robinsons' daughter Elaine (Ross) and he finds himself falling in love with her.
One of the most influential Hollywood movies of the sixties, and, along with Bonnie & Clyde, the precursor to the New Hollywood of the seventies, The Graduate is a landmark comedy drama, which solidified its director's status and made an instant star out of Dustin Hoffman. Very much a product of its time, the film struck a chord with audiences as its protagonist and his struggle perfectly captured the youth rebellion of the time. On top of that, director Nichols also kept the film's style fresh with plenty of French New Wave influences and a killer soundtrack by Simon and Garfunkel only added to the film's youth appeal. Hoffman and Bancroft are fantastic, the widescreen photography great and the film perfectly captures youthful and post-school malaise. The Graduate went on to be nominated for seven Academy Awards, including Best Picture, Actor, Actress, Adapted Screenplay and Cinematography, winning one for Best Director, as well as seven Golden Globe nominations, winning five for Best Comedy, Director, Actress and Best Male and Female Newcomer. It also won five BAFTA Awards for Film, Director, Editing, New Actor and Screenplay, a Grammy Award for Best Original Score Written for a Motion Picture and a Top Ten Film Award from the National Board of Review. In 1996, The Graduate was also selected for preservation in the U.S. National Film Registry as being "culturally, historically, or aesthetically significant". A true Hollywood classic.

கல்லில் வடித்து அசத்தியிருக்கிறார்கள்! அதுவும் கோபுரத்தின் மேலே!! (எனக்கும் கொஞ்சம் கொடு கண்ணா...!)

எட்டாத உயரத்தில் இருக்கும் வெண்ணையை, அரவைக்கல்லின் மீதேறி எக்கி நின்று எடுத்துக் கொண்டிருக்க......
எடுக்கும் போது பானைகள் உருண்டு சத்தம் செய்துவிடாமல் இருக்க, தன்னுடைய மறு கையை பானைகளுக்கு அடியில் தாங்கிப் பிடிக்க......
ஏற்கனவே, சில பானைகளில் இருந்த வெண்ணையை உண்டு ருசி கண்ட அவனின் நண்பர்கள், "தயவுசெய்து எனக்கும் கொஞ்சம் கொடு கண்ணா...!" என்று ஏங்கியபடி காத்துக்கிடக்க......
அதிலும், வலது ஓரத்தில் மூன்றாவதாக இருக்கும் ஒருவன், முட்டிக் கால் போட்டு கெஞ்சிக் கொண்டிருக்க......
'பானையில் இருந்து ஏதேனும் கீழே சிந்தாதா...' என ஒரு எலி காத்துக் கிடப்பதைப் போன்று......
கல்லில் வடித்து அசத்தியிருக்கிறார்கள்! அதுவும் கோபுரத்தின் மேலே!!
''யார் வந்து பார்க்கப் போகிறார்கள்...?'' என்ற அலட்சியம் துளியும் இல்லை!.
இடம் : திருக்குறுங்குடி, திருநெல்வேலி.
(நாயக்க மன்னர்கள் காலம்)

Monday, November 7, 2016

இருள் , மாரிக்கால கானகம்


வெகுநாட்களாக
உறக்கமின்றி தவிக்கும் ஒருத்தி
நாளடைவில்
இரவுகளை வெறுக்கத்தொடங்கினாள்

அவளைக் கண்வருடி
கதைசொல்லி
உறக்கத்திலாழ்த்த தெரிந்தவன்
வெகுதொலைவிலிருக்கிறான்

அவனுடன்
இணைத்துக் காணுகிற
இரவின் சித்திரங்களை
மனச்சுவற்றில் தீட்டிகொண்டிருந்தாள்

தீராத பக்கங்களைக் கொண்டதாக
அச்சுவர்
பெருகிக் கொண்டே இருந்தது

அவ்விரவு வேளைகளில்
நிலைகொள்ளாமல் தவிக்குமவள்
பகல்களை
தன்னிடமிருந்து விலக்க
விரும்புவதேயில்லை

அவனுடைய
வருகை நிகழ்த்தும் பகல்களில்
கிடைக்கிற கதகதகதப்பை
இருள் அவளுக்குத் தருவதேயில்லை.


மாரிக்கால கானகம்
மனதை ஈர்க்கக் கூடிய
மர்மமான பாதைகள் கொண்டதாக
எப்போதுமிருக்கிறது

முன்பு உதிர்ந்த சருகுகள்
நைந்து ஈரவாசனையைப் பரப்ப
மரங்களின் தூர்களில்
பூத்திருக்கும் காளான்களின் மிளிர்வு
அழைப்பை ஒளிர்வுடையதாக்கும்

புழுக்களும் பூச்சிகளும்
பறவைகளும் விலங்குகளும்
உள்நுழைய விழையும் கால்களைத்
தடுக்கும்

மரக்கிளைகளில் வழிந்து
இலைகளின் வழியே
விட்டு விட்டுச் சொட்டுகிற துளி
மறுபடியும் மறுபடியும் அழைக்கும்

ஒருபக்கம் அச்சம்
மறுபக்கம் அழைப்பு என
மழைக்காடு
மறுதலிக்கவியலாத
வசீகரமுடையது

காட்டிற்குள்ளாக
கால்களோடித் திரிய
வாய்ப்பற்ற பருவங்களில்
மனமே காடென விரிய
அவ்வனத்தின்
முடிவுறா புதிர்வெளிக்குள்
முகையரும்பிப் பூக்கின்றன
எண்ணிலியாய் கற்பனைகள்.


Sakthi Jothi

SLEEP STAGES and the so-called "COGNITIVE MAP"


(note: This post appears to be about just "sleep" but it is mainly concerned with how we integrate "space" and "time" into "maps" and so situate our "Selves"...and nightlong alternation between Slow Wave Sleep and Dream Sleep is key )
This recent article from Scientific American is a great review of the epistemological difficulties entailed in the study of our “minding brain’s” map making and how that model of the brain needs to be updated.
Decoding Space and Time in the Brain
https://blogs.scientificamerican.com/…/decoding-space-and-…/
It begins this way: "...henceforth, space by itself, and time by itself, are doomed to fade away into mere shadows, and only a kind of union between the two will preserve an independent reality."
They go on, "This now iconic quote spoken by Hermann Minkowski in 1906 captured the spirit of Albert Einstein's recently published special theory of relativity. Einstein, in a stroke of mathematical genius, had shown that both space and time as independent mathematical constructs were mere illusions in the equations of relativity, conceding instead to a 4-dimensional construct which Minkowski adroitly termed space-time.
While most people are familiar with the ensuing influence Einstein's ideas had on both the academic and public conception of the physical universe, few people are aware a similar revolution against space and time is underway in the fields of experimental psychology and neuroscience.”
We have recently posted on a few "erudite" but fatally flawed publications on the nature of "dreams" and their integration into the Role of Sleep in Making our Way through our lives when we are Awake (we might call it the 'DayJob" rather than the ""Night Job"
We see here, again in this popular article, the customary narrative of how and why we cycle through sleep stages.
http://www.world-of-lucid-dreaming.com/the-stages-of-sleep.…
However, the account that is still so rampant in our popular culture and in our Paparazzi driven media, does not point to the direct linkages which we suspect must exist between Slow Wave Sleep and REM sleep and its dreams.

HOW SEX RULES OUR DREAMS? IS FREUD BACK?
An entertaining and nice BEDTIME STORY
https://www.facebook.com/neuroendocrinology/photos/a.1633019730259383.1073741835.1576160679278622/1870502433177777/?type=3&theater
Today, we have realized how much crucial "consolidation' occurs during Slow Wave Sleep, enabling the hippocampal repository of 'episodically" described moments and experience to be somehow transferred or shared with cortical processes for use in the our next day's and subsequent days' experience and our management of our responses to the events that follow.
There's a fine review of Sleep Consolidation and the exquisite coordinations between parts of the brain going as we sleep available here:
About Sleep's Role in Memory
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3768102/
Just how this ongoing synergy between hippocampus and cortical areas goes on is not yet discussed in any clear manner by neuroscience...although there is increasing aware of the characteristic charting of waves frequency and amplitudes that is associated with that correspondence, much of which arises during the nonREM Slow Wave Sleep periods of our nights.
Once of the prevalent ways of speaking, we have had since Tolman introduced his "cognitive map" notion in the 1940s as a counter to simplistic behaviorist narratives of the mind...is the treatment of the 'minding brain" as one which somehow relies on maps that are formed over the course of experience to guide us in our lives...or "navigating" through, not just mazes and geography but the other aspects of life.
As we have noted here on numerous occasions, the problem with the map narrative is that it is not sufficiently understood by those who speak in terms of the concept. It is universally acknowledged that maps are not the actual territory, but then it is presumed that line between the objective world and the linguistic world is found in structure and that some dedicative rendering provides the isomorphism.
The tendency to think that a 'map", any map, is actually some kind of "picture" of a "territory" is quite insufficient, and, as we see it, mostly misguided.
The cognitive map concept suffers from the same problems as the concept of 'maps" in general Most of us know by now the famous quote by Korzybski, a polymath of the beginning of the last century, "The Map is NOT the Territory"
"Two important characteristics of maps should be noticed. A map is not the territory it represents, but, if correct, it has a similar structure to the territory, which accounts for its usefulness"
But here we have to differ. The 'map" any map is not truly founded on creating an isomorphism between points in space or any territory and some equivalent drops of pigment on a canvas somewhere in our brain, or, more recently the 'hippocampus
This is obvious but it is usually forgotten by those who speak in the 'lingo" of the map. More recently (see below) investigations into the nature of the hippocampus have begun to focus on this aspect of any 'map" rather than its composite via some sort of little "memory" chunks to resemble a territory or space in which we find ourselves.
This kind of 'Map" that somehow mirrors "all' of our Reality would be an incredibly complex and vast map. The question of "storage" of all this information naturally comes up to those who have happened to think this way.
Recently, even the Mosers, have succumbed to this logical mis-step, based on the assumed relation between "territory" and "map" and found themselves ruminating about the 'storage" for such an infinite collection of mapped detail.
"Probing the brain's extensive capacity for storing memories
http://www.sciencedaily.com/releases/2014/…/141208152518.htm
The brain creates and stores memories in small networks of brain cells, with the memories of events and places stored in a structure called the hippocampus.
Researchers have long wondered if there is an upper limit to our capacity to store memories. Nor do they fully understand how we are able to remember so many events without mixing up events that are very similar.
"This indicates that the brain has an enormous capacity for storage. The ability to create a unique memory or map for every locale explains how we manage to distinguish between very similar memories and how the brain prevents us from mixing up events."
This issue of "storage"is a gross mis-step, and one to which the unfortunate language of neuroscience predisposes those who speak of "maps"
As we see it, the problem is not one of 'storage" but of having available a 'gas station" at which to stop and just pick up and put together the maps you need for that particular trip. Or if you're not driving but walking the streets to get another sort of mapping. The brain must do this on the fly in response to salient cues derived from the events of that moment in time and 'what is' doing" and "where it's going".
For example, we have such maps as roadmaps, or subway maps, or pedestrian street maps, or airplane flying maps, and so on. These are based on the "mode of movement" and the possibilities and limitations of how the "vehicle" or movements themselves.
Moreover, when we, or anyone, as we used to do in the good old days, takes a trip, they must decide which of many maps that are available they wish to use on that given occasion.
Similarly as with the drivers of those days, any talk of a "cognitive map cannot be limited to a depiction of an entire vast "reality" in which the user might find themselves. On the contrary, what the brain must do...as any smart travel must do is constantly make choices of just which map and what sort of map is to be relevant on a given occasion.
In the quest to try to understand the hippocampus, for example, this issue has arisen time and again where the hippocampus was found to have 'place cells" and the researchers were off and running in speaking of the map and of something called "allocentric" space.....so that for them the "outside world" or 'space" in which the animal was navigating was "represented" in some simplistic fashion in a pictorially based hippocampus
These issues were addressed by John O'Keefe and his colleagues in the 1970s through a series of studies that cumulated in an elegant theory proposed in the aptly titled book The Hippocampus as a Cognitive Map (1976).
Strikingly, the locations in which place cells fire appears fixed over repeated exposure to an environment, anchoring themselves to environmental landmarks. O'Keefe and Nadel believed that these place cells form the neurological basis of a cognitive map - a map defined by the interrelations of the different elements that compose an environment.
Does hippocampal activity embody the cognitive map? One should expect the neural instantiation of Tolman’s cognitive map to contain units (neurons) that are fully allocentric, that is, identify places in the environment independent of the subject’s perspective (egocentric direction) and ongoing behavior.
We excerpt a few points from a recent neuroscience study below, which expands on the concept we use to speak of the hippocampus in greater detail than most, tells us: Eventually, as they go through seeking to point to "place cell's as points on the map, then "time cells" (see below) and then have to rely on 'grid cells" (see below). the realization arises that a map is not a picture of a space. but is emergent from the movements and possibilities of the 'user" of the map as he navigates
Complementary Roles of Hippocampus and Medial Entorhinal Cortex in Episodic Laboratory of Neurophysiology of Memory,
http://dx.doi.org/10.1155/2008/258467
"Furthermore, one should expect that the neural ensemble composed of these units would be holistic; that is, all the neuronal representations should be tied to one another and change together between environments. And, if the map is to suit the purpose Tolman proposed in guiding behavior according to expectancies, the map should signal the locations of current goals.
Initially, hippocampal place cells seemed to satisfy key criteria for elements of Tolman’s cognitive map. The first complete study characterized place cells as signaling an animal’s location in the environment independent of egocentric direction and ongoing behavior, as would be expected of the units in an allocentric representation
An expansive literature followed on the initial observations, and many interpreted the results as support for the claim that the neural substrate for the cognitive map lies in the circuitry of the hippocampus
As they say, "In sum, place cells do identify where the animal is when important things happen. But place cells do not carry a reliable allocentric signal, and populations of place cells do not operate as a holistic representation of space or anticipate the locations of goals. Therefore, hippocampal neurons do not have the requisite properties to support Tolman's cognitive map.
By contrast, the findings indicate that hippocampal neurons represent events in the places where they occur, consistent with current views of hippocampal involvement in episodic memory .
The recent discovery of spatial firing patterns in the cortex immediately adjacent to the hippocampus has refocused the search for the cognitive map to a zone within the medial entorhinal area
A majority of the data describes the spatial firing patterns of principal neurons in the medial entorhinal cortex, and more specifically how a proportion of these neurons, the so-called “grid cells,” exhibit an intriguing and unique spatial firing pattern with several interesting properties.
First, the relative angles and densities of peaks within grids of neighboring cells remain invariant both across environments and in response to changes in local cues Second, while grid fields of medial entorhinal neurons remain stable in response to modest environmental manipulation, hippocampal CA3 neurons change their rate of firing (“rate remapping,”
The regularity observed in the firing patterns of grid cells does not appear to be derived from environmental features, or any type of sensory information.
Rather, they appear to code a spatial structure that is generated internally within the brain and use it to scaffold the external environment, much in the same manner that Kant had anticipated.
Interestingly, grid cells have been identified primarily within an area of the brain called the entorhinal cortex, one of the primary neural inputs to the hippocampus, suggesting that grid cells provide a source of the spatial framework upon which cognitive maps of environments are formed.
One of our tenets here is that the ostensible involvement of our hippocampus in two seemingly distinct functions, episodic memory and navigation in space, is really very tragically flawed. First, we believe that there have to be principles by means of which these two activities are seen as dependent on similar functionality in the hippocampal area. Secondly, these two aspects are both evidenced right there in the same tissue for more than mere coincidence because we believe that both of those functions of the hippocampus must come into play in the course of either one of them being the apparent focus function.
One of the key aspects of the use of any map is what we are told when we visit any mall and try to find our way. The informational map says, "You are Here Now"...without that we do not have any way of using that map. That too is a key aspect of any 'cognitive map' use....the awareness of the "now" in terms of its integration into the map. That is where the map use starts.
In a more recent very interesting review by the Mosers , called "Mapping Your Every Move" ( https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4087187/) they try to work their way out of the vocabulary "muddle" which they inherited via inheritance ofancient notions of "memory" and "maps" and they state:
"We were surprised to find that cells that have no role in our sense of location actually send signals to place cells, because until now, the specific kinds of brain cells found to be involved in navigation—place cells, head direction cells, and grid cells—all have specific jobs. What is the role of the cells that are not actually part of the sense of direction? They send signals to place cells, but what do they actually do? This remains a mystery."
"We also wonder," they tell us, "how the cells in the hippocampus are able to sort out the various signals they receive. Do they “listen” to all of the cells equally effectively all the time, or are there some cells that get more time than others to “talk” to place cells?""
The rather sloppily defined so called "episodic memories" of which so much is made in psychology talk are not more pictures or representations of the past events...just as the map of the hippocampus is not a picture either. In fact these "episodic memories' are inferred because the person is asked about them and then they must speak and recall what and where they were at that "TIME".
In fact, there was a failure by researchers until relatively recently to appreciate that rodents and other mammals might even have the equivalent of 'episodic memory" function in areas of their hippocampus because the poor creatures could not be asked questions and then have to report on those.
Unsurprisingly all sorts of recent research points to the importance of the lateralized specialization of the hippocampus, where the left side tends to be more involved with performance in response to the demands for 'episodic memory" and indeed in a variety of other types of language use, while the right side is more devoted to the navigation in space.
However, what is also found is that these two sides, two facets of the hippocampus must work together....just as the corpus collosum integrates left and right in general for our brains..so the two sides of the hippocampus both must come into play ..either when traveling in space or via episodic memory, traveling in time.
Any one who has ever tried to travel and avoid getting lost, whether with a map or a GPS or by their own devices, realizes that moving through space is a product of both the allowing oneself to be guided by rules of a GPS or map and simply following those AND additionally the use of landmarks or aspects that are recalled from ones experience. We don't do one or the other. IF we do we find ourselves in the typical GPS predicament where we don't verify via integration of our current spatial frame with our previous temporal frame, whether or not the instructions make sense.
This critical interplay between the lateralized aspects of the Hippocampus is discussed in more detail here, one side being prominent in sequential organization that is describable via the flow of time, and the other side being prominent in spatial organization that is describable via movements in space, with both working together….
Lateralized human hippocampal activity predicts navigation based on sequence or place memory
http://www.pnas.org/content/107/32/14466
“The hippocampus is crucial for both spatial navigation and episodic memory,” they say, “suggesting that it provides a common function to both. Here we adapt a spatial paradigm, developed for rodents, for use with functional MRI in humans to show that activation of the right hippocampus predicts the use of an allocentric spatial representation, and activation of the left hippocampus predicts the use of a sequential egocentric representation.
Both representations can be identified in hippocampal activity before their effect on behavior at subsequent choice-points.
Our findings support the idea of lateralized hippocampal involvement during spatial navigation. The right hippocampus is involved in allocentric or map-based navigation, whereas the left hippocampus is involved in the sequential organization of successive choices. Both representations are active in parallel during the training phase of the task. Overall, we suggest that involvement of the left human hippocampus in remembering narrative prose, learning novel sequences, and in supporting sequential egocentric representations in our study, could reflect a more general role in associative processing of sequential elements of an episode.
Our results suggest that, rather than providing a single common function, the two hippocampi provide complementary representations for navigation, concerning places on the right and temporal sequences on the left, both of which likely contribute to different aspects of episodic memory.”
We should note that, to the extent, that there is any occasion to talk about "the self" by current consciousness devotees, they should consider that the team work between the hippocampus and the cortex and the founding of that teamwork on the integration of left and right sides, verbal movement through time and physical movement through space, both must come into play...and form the basis of any 'self concept" before it is further shaped and massaged by other aspects of our brain.
As the Scientific American article says, " Researchers found that the hippocampus is crucial for encoding the order of visual stimuli - whether pictures on a computer screen or landmarks in an environment - and that it expresses unique patterns of activity during overlapping segments of routes through an environment.
The latter finding is particularly important, as it counters a purely place cell model of hippocampal function during navigation.
In such a model it would be expected that hippocampal activity is consistent during overlapping route segments, as a person's physical location is the same through these portions of an environment.
“Time has proven to be a much more elusive concept for both psychology and neuroscience”, they write. “Despite numerous decades of research, the majority of what we know about time representation in the brain comes from two lines of research: how overlapping events are parsed into discrete episodes and the sequential ordering of those events into a temporal framework
This suggests that the hippocampus is involved in representing more than simply the spatial layout of an environment.
A key breakthrough in identifying which types additional information the hippocampus processes was provided by Howard Eichenbaum and his colleagues at Boston University. In a 2011 paper, the authors proposed a new type of neuron population within the hippocampus which they labeled as 'time cells'.
Through a series of studies with rats, it was found that time cell activity could uniquely code successive events and were able to disambiguate overlapping sequences in temporally organized episodes.
As we believe here that final integration depends as well on the mathematical sense that we have, and many of our other species have as well and which is centered in the parietal cortex (but that will have to await another post)
It is there however that vast amounts of information from all areas of the brain are integrated and decisions made in regard to any such "maps" that we may have and how they might relate to "where we are" in our experiences during the events of daily life."
The Mosers ( "Mapping Your Every Move") are now shifting focus to this more sophisticated analysis,
' It is easy to forget,"they say, "as we move effortlessly from home to job, or from job to supermarket to home, the enormous number of processes and steps that make up our ability to navigate. We are now working our way through different aspects of the brain’s navigational system to better understand how all these pieces fit together.
At the moment we are studying what we have dubbed speed cells—cells that react exclusively to the speed of an animal’s movement—and how these types of cells factor in to the navigational equation.
We’re also looking at decision-making. As an animal moves through a labyrinth, it must choose which way to go or what turn to make next. The neurons involved in this decision-making can be found in the prefrontal cortex, which connects to the hippocampus via a small nucleus in the thalamus."
Our belief here s that there is a direct and highly active connecting path between the posterior parietal cortex, where just about every mathematical related function of our brains is centered and evident, via the retrosplenial cortex right down to that area where the still mysterious "grid cells" are located, the entorhinal cortex, which is constantly the means and mode of interface between the hippocampus and the prefrontal cortex. That deeper aspect of brain coordination will , we believe, to rooted in the math genius of the parietal cortex to integrate a wide range of inputs and allow "decisions to be made".
For those who wish to inquire into this aspect here is a good review of the role of the Parietal Cortex as it relates to this type of decision making ( and note that the Parietal is surely where mathematics gets its life and expression in our brains)
Navigating actions through the rodent parietal cortex
doi: 10.3389/fnhum.2014.00293
These decisions will not be made and could not possibly be made on point to point analysis of vast arrays of information and 'matching' of past with present, but have to be processed in a way that is characterized by enhanced speed and efficiency (that allow survival and adaptation" as the availability of any algorithm is to plodding through calculations and data points.
This means that there is a whole lot of 'putting things together" in useful ways based on the user's capabilities and destinations that takes place. It is therefore not sufficient when we speak about sleep and its consolidation, for instance, to just leave it at that, and consider the Slow Wave Sleep to be sufficient conceptually to get our 'map" or "maps' in order.
As the Mosers have recently acknowledged,
"We now know that this coding system works like your own air traffic controller—monitoring every movement you make, knowing every step you ever made, and creating links to every event and experience you have had. Essentially, while your brain is making mental maps to help you navigate, it is also overlaying memories—experiences, smells—onto those maps.
They say, "This ability of the brain to overlay recollections creates a cognitive map—a multilayered collection of memories—rather than a mere cartographic map. It also means that learning how the brain computes navigation is a step toward understanding how networks are built up in the cerebral cortex, the part of the brain that is responsible for imagination, reasoning, and planning—thought processes that make us human. "
What must happen then for the person sleeping is that the organization of that 'map library", let's call it, in terms of events in their lives...must then be enacted in such a way that the work of that night proves useful to finding one's way in the world the next day.
The conclusion (from Scientific American)here is one the share whole heartedly"
"If our experience of time and space share similar neural correlates, it begets a fundamental question: are space and time truly distinct in the mind, or are they the product of a generalized neurocognitive system that allows us to understand the world?
While Kant had much more to say about space than time, contemporary cognitive neuroscientists have begun composing theories to address this question.
One proposal by Demis Hassabis and Eleanor Maguire suggests that the primary function of the hippocampus isn't to think about past and future, or to move about through space per se.
Rather, through cooperation in a larger network spread throughout the brain, the hippocampus allows us to construct a representation of the world in a spatiotemporal context that affords the ability to simulate past experiences in order to make predictions about the future, and to ultimately use this information to direct action in the present.”
They conclude, “Specifically, it suggests that the hippocampus is able to tune its activity to both spatial and temporal aspects of an experience, depending on what type of information needs to be encoded or recalled"
Our view of this "movement' is that it requires essentially moving through two spaces at once and the integration of those 'movements": The movement of our bodies through the three dimensional space of geometry and our placement with its three dimensions and, as well, the one dimensional space normally labelled "time" and our movement through that space via the language we use.
The REM sleep and its progressively increasing dreaming that occurs after the progressively increasing Slow Wave Consolidation events of the night must be giving us not only chunks of 'map" in some generic and vague sense of the word, but "maps based on different episodes in our lives" and useful for different purposes in our lives that might just happen.
And indeed these various guides for behaving must all be indexed and related to each other so that wherever we "are" or "wherever we might be headed" the next day we will be able to call up and use the right one for that mode of movement and that purpose.
Thus what we experience as the dreams of the REM state are the combination and permutation and the "trying on for size" of the work done earlier in the night via the consolidation of the hippocampal content into the cortex.
Do they represent fantasied "wish fulfillments"? Perhaps. But more likely they represent the anticipatory schema by means of which the hippocampus always works, day or night. Do they predict the future? Not exactly, but in some way they do..because they determine what manner of map we just might be using , and how it is put together...so they do predict how we are likely to try to make our way in the world when we are awake....either tomorrow or in the future.
For now, that's a nice part of the story of our nights and dreams that we must appreciate....and indeed that is how evolution must have worked its magic hand to allow all that to happen at night.
We should not close our eyes to all the rest that transpires between Slow Wave Sleep and our Dreams. There are countless maps, in fact an infinite number of them that are made possible by these processes that occur during sleep.
We may never use many of them or most of them. Perhaps sometimes we do, however, have to dig down and find re awaken those "maps" for ourselves. That may be how some mysticism works by encouraging us to lend credence to those dreams. and that is surely how much psychotherapy seeks to bring us 'back in touch" with our dreams...since they just might be the maps we forget to use.
And they might lead us the those "roads less traveled" if we conjure up those maps to guide us if we realize that our journey is very much based on which maps we bring with us...and which bring us.
What we believe is that, while it makes good sense to finally provide a narrative of how our bodies in a three dimensional geometric space move around and find their way to new places and experiences, it also makes sense to speak of our "Selves' are traveling in one dimension, that of verbally mediated (integration of past moments) and how that Self can find its way in that one dimension related to time to new experiences.
Just as we noted occurs whenever we "go" somewhere on whichever roads we travel, there is an essential back and forth that must occur between the past "episodic" elements ordered in time and the present spatial plans and movements oriented in space.
This recent publication deals with \interactions between the prefrontal cortex and the hippocampus as they play a critical role in the modulation of goal-directed self-action and the strengthening of episodic memories
A Prefrontal-Hippocampal Comparator for Goal-Directed Behavior: The Intentional Self and Episodic Memory
10.3389/fnbeh.2015.00323
These authors write "Action plans are essential for successful goal-directed behavior, and are elaborated by the prefrontal cortex. When an action plan is initiated, the prefrontal cortex transmits an efference copy (or corollary discharge) to the hippocampus where it is stored as a working memory for the action plan (which includes the expected outcomes of the action plan).
The hippocampus then serves as a response intention-response outcome working memory comparator.
Hippocampal comparator function is enabled by the hippocampal theta rhythm allowing the hippocampus to compare expected action outcomes to actual action outcomes. If the expected and actual outcomes match, the hippocampus transmits a signal to prefrontal cortex which strengthens or consolidates the action plan.
If a mismatch occurs, the hippocampus transmits an error signal to the prefrontal cortex which facilitates a reformulation of the action plan, fostering behavioral flexibility and memory updating.
The corollary discharge provides the self-referential component to the episodic memory, affording the personal and subjective experience of what behavior was carried out, when it was carried out, and in what context (where) it occurred."
However as we noted above, the exquisite "mathematical sense of the parietal cortex" must play a role here as it does in most of our actions, although mathematics is not fully appreciated as being at the core of our Selves and of our Brain Function.
It's our central mathematical sense and capacity that allows such an "integration" and in the course of that integration we find ourselves experiencing a Self as an index of that integration and not located within either time or space data points.
Thus in "Navigating actions through the rodent parietal cortex (see the link above)
they write, "parietal neurons encoded route progress irrespective of spatial position or direction of motion, and the fact that they did so equally well in darkness or light implied a possible function in path integration.
Based on the finding that PPC firing fields, unlike hippocampal place cells, scaled flexibly to match maze segments when they were lengthened or shortened, it was concluded that PPC cells were more tightly linked to the reference frame of the animals' route than a world-based spatial reference frame
Many of the basic questions relating to cognitive motor functions, though, are not necessarily specific to one species or another—such as the time course over which a movement plan evolves relative to action initiation, the cortical representation of movement goals, or the computational contribution of common anatomical pathways.
Evolutionary date implies s that place cells and grid cells date back at least 65–100 million years to the common ancestor of placental mammals and it is quite likely that such spatial circuitry arose long before in even simpler, more ancient organisms.
The same principle applies to the parieto-frontal pathway, which is another common feature of all mammalian nervous systems.
As opposed to generating spatial maps, it enables the synthesis of efficient movements and meaningful interactions with objects within those spatial maps, computing behavioral solutions to everyday problems which terrestrial vertebrates have encountered for countless millennia."
In the end, it is not some indefinable, dualistically problematic, Self, however, which magically travels and puts together various decisions and game plans for moving through space and/or time...but it is the need to conduct those movements by an organism's brain which requires it to experiences its moments of life via a 'Self".
The "reality" of the Self leads to much, far too much, endless quibbling about issues that only beg of our understanding of that notion, many of them dependent on 'locating" a "Self" as an entity, or, as we prefer to say, "entitizing it" as existing in either/or both space and time.
That is how we put 'space and time" together to function as organisms That is how the 'self" can be considered quite "REAL" but not situated in either space or time. In fact our "self" and our "self talk" are ordered very much as are the natural numbers in one dimension as we know it is the "measure" of time just as much as our geometric "maps" of our movements and their possibilities is a measure of “space"
If, however, we consider what we believe to be the "reality" status of the "center of gravity" when we discuss natural law via Newtonian theory, we realize that this concept of “self” not outside of space and time but being a manifestation of our computation of space and time, is as "real" as anything of which we can speak, as it allows us to engage in the vary acts of speaking that describe how movement occurs in space and change arises over time.
As Anais Non wrote, "Dreams pass into the reality of action. From the actions stems the dream again; and this interdependence produces the highest form of living." -

Sunday, November 6, 2016

இதிகாசப் பெண்கள் - ராதை (கதையிலிருந்து ஒரு பகுதி )


"ராதை எனக்கு உங்கள் சம்மதம் மட்டும்தான் முக்கியம் . இந்த ஊரைப் பற்றி எனக்கு கவலையில்லை .வயதில் மூத்தவர்ளை ஒரு ஆண் திருமணம் செய்யக் கூடாது என்பதில் எனக்கு உடன்பாடு இல்லை .ஆணுக்கும், பெண்ணுக்கும் இடையேயான திருமண வயதுப் பற்றி, இந்த சமூகம் சொல்லும் விஷயம் எனக்கு ஒரு பொருட்டு இல்லை . இரண்டு மனங்கள் இணைந்தால் , இடையே வேறு ஒன்றும் தடையில்லை . வயதென்பது எண்ணிக்கை தானே தவிர , வேறில்லை ஆரோக்கியமான மனமும் , உடலும் மட்டுமே காதலுக்கு வேண்டும் .உங்கள் மனதை தொட்டு சொல்லுங்கள் ராதை உங்களுக்கு என் மேல் காதல் இல்லையென்று ." பதில் சொல்லாது ராதை மவுனித்தாள் . அவள் பார்வை எந்த பொருளும் இல்லாமல் கண்ணன் மேல் பதிந்து இருந்தது ராதையின் மவுனம் கண்ணனுக்கு அவளின் சம்மதமாக தோன்ற மிகுந்த உற்சாகத்துடன் பேச முற்பட்டான். ஆனால் ராதையோ மிகவும் உறுதியான குரலில் கண்ணனை கேட்டாள்
" கண்ணா நீ எல்லா விசயத்தையும் எல்லா பெண்களிடமும் சிரித்து பேசுகிறாய் அப்புறம் ஏன் என்னிடம் மட்டும் தொடர்ந்து ஐந்து நிமிடம் உன்னால் பேச இயலவில்லை? " ராதையின் குற்றச்சாட்டு கண்ணனுக்கு சிரிப்பாக இருந்தது .தான் பேசியதை குறித்து அவள் பெரிதாக விமர்சிக்கவில்லை என்ற ஒரு விசயமே கண்ணனுக்கு உற்சாகத்தை கொடுத்தது
." ராதை ... நீ புத்திசாலி என்று நினைத்தேன் . அது மற்ற விசயங்களில்தான் போலிருக்கிறது . ஒரு ஆண் தான் காதலிக்கும் பெண்ணிடம் காதலை சொல்லும்வரை அவனால் அவளை இலகுவாக எதிர்கொள்ள முடியாது . அதற்கு நானும் விலக்கல்ல உன் மேல் எனக்கு தீவிரமான காதல் இருப்பதால் , என்னால் உன்னுடன் சகஜமாக உரையாட முடியாமல் ஒரு தயக்கம் என்னை சூழ்ந்து இருந்தது இப்பொழுது நான் என் காதலை சொல்லிவிட்டேன் இனி நமக்குள் எந்த பேதங்களும் இருக்காது .இனி நான் இன்னொரு பெண்ணை பார்த்தால் கூட உனக்கு தாங்காது ." என்று சொல்லி சிரித்த கண்ணனைப் பார்த்து ராதை ," என்ன கண்ணா நீயே பேசினாய் .. நீயே முடிவு எடுத்து கொண்டாய் , இதில் என் சம்மதம் எதுவும் வேண்டாமா ?" என்று கோபமாக கேட்க ,' எனக்கு உன் உதடு கொடுக்கும் சம்மதம் தேவையில்லை ராதை . உன் கண்கள் எனக்கு சம்மதம் கொடுத்து விட்டது அது உன் ஆத்மா கொடுத்த சம்மதம் . அது போதும் எனக்கு . மனதை மறைத்து நீ பேசலாம் . ஆனால் என் கண்களை சந்திக்கும் உன் கண்கள் எனக்கு உன் மனதை சொல்லி விட்டது ." என்று சொல்லிக் கொண்டே ராதையை இழுத்து அந்த மகிழம் மரத்தடியில் முதன் முறையாக முத்தமிட்டான் கண்ணன் . இதுவரை அவன் எத்தனையோ பெண்களை முத்தமிட்டு இருந்தாலும் , ராதையின் முத்தம் போல் வேறு எந்த முத்தமும் இருக்கவில்லை என்று அவன் சிந்தனை சொல்லியது . இருவருக்குள்ளும் ஆத்ம பரிவர்த்தனை சங்கமத்துடன் இந்த முத்தம் அரங்கேறியதால் , அந்த சுகம் விண்ணையும் தாண்டி பெருவெளியில் மிதந்தது.

Govindarajan Vijaya Padma

Engine from a Mercedes SLR

VEHICLE TYPE: front-engine, rear-wheel-drive, 2-passenger, 2-door coupe
ESTIMATED BASE PRICE: $480,000
ENGINE TYPE: supercharged and intercooled SOHC 24-valve V-8, aluminum block and heads, port fuel injection Displacement: 332 cu in, 5439cc Power (SAE net): 641 bhp @ 6500 rpm
Torque (SAE net): 605 lb-ft @ 4000 rpm

TRANSMISSION: 5-speed automatic with manumatic shifting
DIMENSIONS: Wheelbase: 106.3 in Length: 183.3 in Width: 75.1 in Height: 49.3 in
Curb weight: 3800 lb

PERFORMANCE ( C/D EST):
Zero to 60 mph: 3.5 sec
Zero to 100 mph: 7.8 sec
Standing ¼-mile: 11.5 sec
Top speed (redline limited, mfr's claim): 209 mph

PROJECTED FUEL ECONOMY ( C/D EST):
EPA city driving: 13 mpg
EPA highway driving: 18 mpg


Rains on different worlds.