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." -

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.

The original model of the USS Enterprise in 1965.

Can you accelerate to the speed of light?

This one is easy to answer; we pretty much agree that you can’t. But when I think about reasons often given for this barrier I found a flaw in the reasoning routinely given. The same kind of error was once made by Einstein himself and later corrected it, the error is called ‘frame switching’, that is, attributing to one frame the measurement made by another.

I’m not going to dwell on the incorrect solution but move right along to the correct one.

Let us employ the popular twins of The Twin’s Paradox fame. The twins initially share the same inertial frame and then one accelerates away.

We know that, from Special Relativity, the mass of the accelerated twin increases with his speed relative to the stay at home twin. If the unaccelerated twin is providing the power to push the accelerated twin then the amount of energy will not increase linearly with increasing target speed but will rise much quicker as the inertia of the moving twin increases, eventually rising to infinity.

So we know that we can not accelerate an object to the speed of light that way.

Now we consider the other case, rockets on the accelerated twin’s vehicle. We note that each twin calculates the same speed difference between them. Assume that the accelerated twin accelerates in bursts and then coasts. Each time the accelerated twin coasts he can count himself stationary and the other twin to be the one that is moving. It takes no more energy to accelerate by 1,000kmh from any speed that the twin obtains because at any speed he can count himself stationary and there is nothing in Special Relativity or physics that can dispute this. Thus to add another 1,000kph never takes any more energy at any speed, that is, it does not take any more energy to accelerate from stationary (at rest with the other twin) or from 280,000kps

What stops the twin from reaching the speed of light is not some barrier of any kind, but the problem that he would run out of universe to accelerate in. At the speed of light the distance between any points in the direction of travel falls to zero and the interval to travel that distance falls to zero, so there simply isn’t any more universe left, even an infinite universe would not solve the problem.

We may try to argue the addition of velocities but that only applies if an object leaves our accelerated twin’s rocket at some speed in the direction of travel and only by the measure of the unaccelerated twin. As far as the accelerated twin is concerned, he is at rest before each acceleration step…

What the accelerated twin would notice is that the universe seems to be getting ever shorter in the direction of his travel, so there is some indication of motion by that measure. Eventually, the whole universe would appear to be compacted to a point, so no further acceleration is possible for that reason.

I have seen written that as the accelerated twin gains mass it becomes increasingly difficult for that twin to accelerate. This is not the case. It becomes more difficult for the unaccelerated twin to push the accelerated twin (because he measures the increase of mass, the accelerating twin does not) but not for the accelerating twin that can accelerate forever, or until he runs out of universe which will occur before he reaches the speed of light.

The key points are:
1) The accelerated twin’s inertial frame has the same mass, length, and temporal frequency (clock rate) regardless of his speed (Einstein said that all the physics remains the same);
2) At the speed of light the accelerated twin would literally leave the universe for any measurable interval on his clock.

Note also that the energy of the rocket for each acceleration will be measured differently by the two twins. The unaccelerated twin will measure each ‘burn’ as taking ever longer as the speed increases but temperature and pressure decrease (power decreases, thrust decreases), thus he measures the same energy (power * interval) for each burn.

Note also that if the amount of energy required to accelerate changed with your speed then, using a fine enough measurement you could determine when you were absolutely stationary (as this would require the minimum energy for acceleration) thus establishing a preferred or absolutely stationary inertial frame, in violation of the most basic principles of relativity theory ie there is no preferred or absolutely stationary inertial frame (from which all other frames could be compared or measured).

 To many, the speed of light being the ultimate speed limit is a fundamental law of physics. Albert Einstein believed that particles could never travel faster than the speed of light, and doing so would constitute time travel. For those that regret something in theirpast this is potentially an interesting question. For those who have led a completely perfect life, it is an interesting piece of knowledge to have nonetheless. There are also other reasons to research this question. The closest star, other than our sun, is Proxima Centauri and is about twenty five trillion miles away, which would take over ten thousand years to reach with the fastest spaceship we have today.Therefore if we ever wish to truly explore our universe we must start to explore the limitations of our transport.

To answer this question I must first define a few parameters. As the question stands it is rather ambiguous. I could say yes, but then slow light down before conducting my ‘race’, and then show that the particle did indeed travel faster than the light did. There are many ways in which this can be achieved, for example a Danish physicist named Lene Vestergaard Hau was able to slow light down to 17m/s, roughly thirty eight miles per hour, enabling my car to travel faster than light. They achieved this by cooling Bose-Einstein condensate atoms to a fraction of a degree above absolute zero, before passing the beam of light through it.Obviously this is cheating, using the the wave-particle duality of light to think of light as a particle, we know that the light is still travelling at the speed of light in a vacuum, it just has further to travel, as it interacts with all the particles in the material. I.e. the light has had the distance it needs to travel extended, in much the same way as the resistance of a metal increases when it is heated up, as the electrons collide more often with the ions in the metal and therefore take longer to travel through it.Therefore it is only fair to define the speed of light as the speed of light in a vacuum, known as c, which is 3.00×10⁸ m/s to three significant figures. We commonly slow light down in every day life, when it bends through glass for example, but does this mean we can speed it up? Can we make light travel faster than light?

This is known as Superluminal Propagation and is the first faster-than-light example I would like to talk about. It seems possible to send pulses of light faster than c over small distances, however interpreting these results has been difficult because the light pulses always get distorted in the process.In 2000 Mugnai reported the propagation of microwaves over quite large distances, tens of centimetres, at speeds 7% faster than c. Impressive as this is, research by Wang has shown a much larger superluminal effect for pulses of visible light in which the light is travelling so fast the pulse exits the medium before it enters it. The observed group velocity has been calculated as -c/310 . The easiest way to understand this negative velocity is to interpret this value as meaning the energy of the wave moved a positive distance over a negative time. In other words the pulse emerged from the medium before entering it. Although light can be considered as a particle the photon has no mass, so this is not a true example of a particle travelling faster than c.

The second thing I will talk about is special relativity andits consequence, time dilation. The theory of special relativity states that the speed of light is constant in all reference frames. As a result of this the speed of light cannot be altered, if I was driving a car at half the speed of light and I turned on the headlights, the speed of light would still be measured as c, rather than 1.5c, as might seem logical. This is perhaps counterintuitive as with much smaller speeds we would add velocities, for example driving a car at 50mph and throwing a stone at 20mph in the same direction, would result in the stone having a velocity of 70mph in that direction. To illustrate time dilation I will show the effect of moving at high speeds on two clocks.

In this situation the clock works by bouncing light between the two mirrors A and B, this represents one tick, so for the sake of argument I will say that it takes one second for the light to travel the full distance between the two mirrors or 2L. Both images depict the same clock, however the one on the right is moving close to light speed in relation to the other. The speed of light must be c in both frames, however as you can see the light has further to travel in the moving clock. As 2D is longer than 2L, the moving clock appears to be running more slowly from the frame of the stationary clock. Using these two examples it is possible to derive the change in time and thus the time dilation. The first clock gives us the simple equation   and the moving clock shows  . Using Pythagoras theorem we can show that  , this can then be substituted back into the equation and rearranged for , finally giving  .

This expresses the fact that time slows down the faster you go. The main point of this is that it is possible to travel a distance of one light year in less than a year. This statement needs explaining however because for a stationary onlooker, say a person on earth, the journey time will appear to be much longer than a year. However the traveller will have experienced less than a year. This is common at CERN where short-lived particles, such as muons, with a mean lifetime of 2.2 microseconds, are accelerated which hugely extends their lifetime. As we have no stationary point to measure the universe from, due to the Earth’s constant movements, we will never have standard time. A clock on Earth synchronized with one light years away on a distant planet will not stay in sync for very long, the mass of the planet and its velocity determine the experience of time. From here I can crudely argue that if there will never be a standard time the one that matters the most is our own. Having said that I have not proved that it would be faster than light, this is a slightly unscientific argument, however it is interesting to say that if there were no other people in the world to offer an alternative view I would say that I can travel faster than light.

My next example involves space-time distortion. After the Big Bang the universe expanded at a rate much faster than 3.00×10⁸ m/s.Special relativity does not provide a limit for distorting space-time. Miguel Alcubierre hypothesized that a spacecraft could be enclosed in a ‘bubble’ and exotic matter could be used to rapidly expand space-time at the back of the bubble, making you move further away from objects behind you, and contacting it at the front, bringing object ahead of you closer. This would be a new way of travel in which it would be space-time which is moving rather than the spaceship. In this way the ship would reach a destination much faster than a beam of light travelling outside of the bubble but without anything travelling faster than c inside the bubble.[6]This method has one important drawback, It violates the weak, dominant and strong energy conditions, both the weak and the dominant energy conditions require the energy density to be positive for all observers, therefore negative energy is needed, which may or may not exist.[7]

A particle which is always travelling faster than the speed of light is known as a Tachyon. Tachyons, if they exist, would both answer my question immediately and have very interesting properties. The equation   has often been used to show that particles with mass can never achieve the speed of light, this is because it would require infinite energy. However if the same equation was applied to tachyons, it would show two things. Firstly, a tachyon would never be able to decelerate below the speed of light, as crossing this limit from either side would require infinite energy. Secondly it would have an imaginary mass. When v is larger than c the denominator in the above equation would become imaginary, as the total energy must be real the numerator must also be imaginary. Therefore the rest mass must be imaginary, as an imaginary number divided by another imaginary number is real.The existence of tachyons would cause certain causality paradoxes. If they could be used to send signals faster than c, then if one frame is moving at 0.6c and another is moving at -0.6c there would always be one frame in which the signal was received before it was sent. Effectively the signal would have moved back in time. Special relativity claims the laws of physics work the same in every frame, if it is possible for signals to move back in one frame it must be for all of them. Therefore if A sends a signal to B which moves faster than light in A’s frame and therefore backwards in time in B’s frame. B could then reply with a signal faster than light in B’s frame but backwards in time in A’s frame, thus it could end up that A received the reply before sending the original message, challenging causality and causing paradoxes.

The mathematical case that prohibits faster than light travel uses the Equation E=MC², shows that energy and mass are the same thing, this equation implies that the more energy you inject into a rocket, the more mass it gains, and the more mass it gains, the harder it is to accelerate. Boosting it to the speed of light is impossible because in the process the rocket would become infinitely massive and would require and infinite amount of energy.

A wormhole is effectively a shortcut through space-time. A wormhole connects two places in space-time and allows a particle to travel a distance faster than a beam of light would on the outside of the wormhole. The particles inside the wormhole are not going faster than the speed of light,they are only able to beat light because theyhave a smaller distance to travel. Scientists imagine that the opening to a wormhole would look something a bubble. It is theorized that a wormhole allowing travel in both directions, known as a Lorentzian traversable wormhole, would require exotic matter. As they connect two points in both space and time they theoretically allow travel through time as well as space. This fascinated many scientists and Morris, Thorne and Yurtsever worked out how to convert a wormhole traversing space into one traversing time. This process involves accelerating one opening of the wormhole relative to the other, before bringing it back to the original location. This uses a process I have mentioned earlier, time dilation. Time dilation would cause the end of the wormhole that was accelerated to have aged less. Say there were two clocks, one at each opening of the wormhole, after this tampering, the clock on the accelerated end of the wormhole may read 2000 where as the clock at the stationary end showed 2013, so that a traveller entering one end would find himself/herself in the same region but 13 years in the past. As fantastic as this may sound there have been many who believe it would be impossible, there are predictions that say that a loop of virtual particles would circulate through the wormhole with ever-increasing intensity, destroying it before it could be of any use.

Over the course of this essay I have shown a few ways in which the speed of light can be ‘beaten’, but ultimately I have failed to produce any proven faster than light particles, and for this reason I must conclude that particles cannot travel faster than the speed of light. However the topics I have raised are still in the developing stage, I have shown that there are many diverse areas of physics which are both being explored and need exploring. Many of these areas are still heavily theoretical and are under further research, but our technology is increasing at an exponential rate and the human race is steadily getting smarter, so with time and perseverance we will know the answer to questions such as these and many more. To infinity, and beyond.

Thanks Robert Karl Stonjek

 

Eiffel Tower Structural Drawing

A Short History of Smearing

For over hundred years now young painters look at Modern Art and its  various styles,approaches and techniques and being young they get tempted almost each week in different direction  To be as tight and illusionistic as Ingres or as grotesque as Otto Dix, to be painting so magically that everything would seem to appear as if behind a mirror... That would impress anyone.
But, another demon would beckon toward particularly naughty direction, where thrill of doing something that everybody knows should not, not ever be done is tempting. Something as rebellious and defiling that even thought of it would be frightening to the civilized part of the mind. But- the part that secretly shines shoes with lacy curtains and pours ink to the aquarium wants to do it. The consequences might be very unpleasant and at the same time presenting a new you, not that flaccid ne'er-do-well but a formidable risk-taker, artistic buccaneer,almost a salto-mortale motorcyclist!

A  crowd of uncoordinated, devoid of  manual dexterity, impatient art-lurkers promote hopeful wish  that figurative art is either dead or should be dead. They sense that somehow there ought to be another way into artistic success than talent and tedium of learning.

Figurative art is not promising any "fun"[there is immense ,long lasting Joy in painting, but indeed ,no fun]. Let's declare representational art dead  and by necessity of moving forward let us try yet untried. What possibly could be more antithetic to painting as much as  smearing?

The original first smearer,as it often is with claims of originality it may be disputed but in all events among the very first brave smearers  remarkable work of Jewish émigré from Russia ,Chaim Soutin should be recognized. Everywhere in contemporary art of that time paintings still retained disciplined, tight form in drawing  and young Soutin broke that confining restrain. Not being able to draw , like not being able to play piano is something most people share.

However, not being able to play the piano and giving piano recitals would be new and untried. By this analogy not being able to draw, to reflect on canvas some disciplined ,representational forms and yet obtaining great fame as prominent painter is a feat no Pianist-Who-Can-Not-Play-The- Piano has achieved. Feats like that are astounding .In other fields golden nimbus of fame and universal admiration  is given to the very few highest achievers. We see no Polar Explorers who never went to polar regions and we do not see renown swimmers who do not know how to swim. Yet,in the difficult art of painting it has been possible to manufacture by the skillful uses of Dark Magic great fame and a lasting place in the pantheon of greatest artists for someone who could not neither draw nor paint.

Then,another triumph of promotion became visible and this time no longer in Paris but over the famed skyline of New York City.His name was Franz Kline.

It is hard to imagine how something so obviously ugly and chutzpiatic could ever find itself on public display, let alone national museums.And yet:

 ", Kline's work is distinct in itself and has been revered since the 1950s"

"says wikipedia. Reverence,no less......

 "Kline's paintings are deceptively subtle. While generally his paintings have a spontaneous, and dramatic impact, Kline often closely referred to his compositional drawings. Kline carefully rendered many of his most complex pictures from extensive studies."-
 one can see how much meticulous preparatory "studies" conducted by the Master with aid of  interns and aspirants it must have taken before the first brushstroke appeared on canvas. Franz Kline was also known for avoiding giving meaning to his paintings, In a catalog of Kline's works, art historian Carolyn Christov-Bakargiev writes that "his art both suggests and denies significance and meaning" and what a meaning it may suggest! On top of that, just to be inscrutable-he would deny any meaning or even significance -what an appropriately naughty artiste-maudit teasing coyly  the adoring historians into writing about the smears as if their meaning was as dense as a collapsed red dwarf.

When it comes to the greatest,most delightfully haphazard,deliciously emetic art of smearing the golden palm should be handed to Hans Hofmann,the very Pope of Smearing.

Through a painting, we can see the whole world" said Hans Hofmann.I am not certain he meant his painting

And one more for our edification: Frank Auerbach.

" His work is not concerned with finding a visual equivalent to an emotional or spiritual state that characterised the expressionist movement, rather it deals with the attempt to resolve the experience of being in the world in paint."-so,his paintings are some kind of psychological trial of vague angst experienced by "being in the world".The result of this unusual situation,of being "in the world" and precisely in Camden  part of London  calls for "resolving" through the means of gobbing ,pooling and scraping a greasy dump of accumulated paint.

".......results in an astonishing desire{it really must be "astonishing"] to produce an image the artist considers 'right'. This leads Auerbach to paint an image and then scrape it off the canvas at the end of each day, repeating this process time and again, not primarily to create a layering of images but because of a sense of dissatisfaction with the image leading him to try to paint it again" No  kidding,who would react differently but scrape the thing and perhaps look for the work he could succesfuly do.

"This also indicates that the thick paint in Auerbach's work, which led to some of Auerbach's paintings in the 1950s being considered difficult  to hang, partly due to their weight and according to some newspapers the paint fell off"-that quote shows how not all of it is glamour and riches : paint falls off,people are jeering...

There is a very general set of pre-existing rules of how to do something if we want a particular result. Taking part in figure skating competitions requires without exceptions very fluent skill of skating. One cannot get a job as UN translator without knowing well foreign language.

Actions taken in the process of painting are organizing paint into intense,emotional illusion of three-dimensional image, thus hiding means by which it was achieved. The degree of illusionism varies with styles and unique touch of the artist but the fundamental illusion of paint appearing as objects of the world depicted ; that fundamental  rule obtains. Clearly, subversive forces embedded in XX century culture started the perversity of definitions on all fronts and art is just one of its victims. What has always been a joke has become a rule and what humanity everywhere  and always understood to be in a certain way has been hung upside down and ridiculed .

Because I wanted to conclude this post without fury,I am including one of Meredith Frampton's paintings.Can you imagine him at an art-opening with those new giants?

Thagainstmodernart.blogspot.com.

New research suggests sleep doesn’t just help learning, it helps “relearning” as well

Sleep appears to be important for long-term potentiation, a strengthening of signals between neurons that is widely regarded as a mechanism of learning and memory. Certain memories acquired during the day appear to be reactivated and “replayed” in the brain during sleep, which may help make them longer lasting. In some instances the amount of improvement that occurs on memory tasks positively correlates with the length of time spent in certain stages of sleep.

To date, most sleep and learning research has focused on recall, which is the capacity to remember information. However, new research by Stéphanie Mazza and colleagues at the University of Lyon, recently published in the journal Psychological Science,suggests another potential benefit of sleep: improved relearning. Relearning refers to the process of re-acquiring forgotten information. Because we cannot possibly remember all of the information that we encounter, it is often necessary to go back and learn that information again. That’s when relearning occurs—such as when preparing for an exam, taking a refresher course, or simply revisiting a topic after an extended period of time. According to this new research, sleep supercharges relearning: it can enable us to relearn twice as quickly and up to three times more effectively.

Cecile G. Tamura

 

We’ve all stayed up the night before an exam to do some late-night cramming, but we might have been going about it the wrong way. It turns out that only about 20% of the potential brain function is on the go between 10pm and midnight, explaining why it’s so hard to stay on track. However a 2010 study found that a quick nap can work wonders on our brain’s ability. The study, done by Harvard University, showed that students that slept and dreamt for 90 minutes before being given a puzzle scored much higher than their peers. Scientists believe that dreaming has a positive effect on memory recall and concentration, giving you a great reason to hit the sack early tonight.

Read more at: https://www.stayathomemum.com.au/my-lifestyle/20-mind-blowing-facts-about-sleep/

 

SIM Card Sizes

 

SIM cards come in three different sizes: Standard SIM, Micro SIM and Nano SIM. The right size of SIM card to fit in your handset will depend on the manufacturer and the model of your smartphone.

As of 2015, most new smartphones are either using Micro SIM or Nano SIM.

Handsets requiring a Micro SIM include the Galaxy S5, Galaxy Note 4, LG G4 and Moto G. If you’re changing to a smartphone which requires Micro SIM, you might need to change the size of your SIM card. You can order a micro-sized SIM card directly from your mobile network.

Handsets requiring a Nano SIM include the latest flagship smartphones from Apple and Samsung (e.g. the iPhone 6s, iPhone 6s Plus, Galaxy S6 and iPhone 5s). The Xperia Z5 and HTC One M9 also use nano-sized SIM cards. You might need to change the size of your SIM card when upgrading to a handset which uses Nano SIM. You can order a nano SIM directly from your network.

All three SIM card types work in the same way from a technical perspective: they only differ in the amount of plastic housing that surrounds the metallic chip.

If you’re willing to take the risk, it’s possible to cut your Standard SIM down to Micro SIM dimensions (e.g. with a Micro SIM cutting tool). However, we’d normally advise against doing this: instead, it’s easier and safer to order a Micro SIM directly from your mobile network. It’s normally free and you won’t risk invalidating your phone’s warranty with a badly-cut Micro SIM.

It isn’t possible to cut your own Nano SIM. This is due to the differences in thickness between Nano SIM and other types of SIM card.