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Thursday, July 9, 2015

What is Problem based learning (PBL) ?



“True learning is based on discovery guided by mentoring rather than the transmission of knowledge.”

John Dewey


Introduction and History


In simple terms Problem-based learning (PBL) is a student centred education in which students learn about a subject through the experience of creating a problem. Problem- based learning or what we simply called PBL is based on research in the cognitive sciences on how we learn.

This educational strategy was developed at the McMaster University Medical School in Canada in the 1960s in medical education. Efficacy of this revolutionary learning method has made it popular among educationists and It is one of the big success stories in the education in the past few years.   But nowadays PBL is developed and implemented in a wide range of domains around the world. This approach empowers learners to conduct research, integrate theory and practice, and apply knowledge and skills to develop a viable solution to a defined problem .In simple words this simple revolutionary idea that problems should come before answers drives PBL.  Beginning with a problem puts you in the driver’s seat.  You can use your previous knowledge, your hunches, and your wildest ideas to try for a solution.  In the process you can develop an inventory of what you know and what you need to know to get to a solution.  Once you know that you can start questioning your instructor or your classmates, plundering the library, surfing the net, or bugging the many excellent experts to fill your needs. 

What is the difference between Subject based learning and Problem Based learning




What is wrong with the old teacher stand up and talk student sit and listen learning?  It doesn’t meet the needs.  It is too slow, too shallow, too inefficient and not much fun.  Students retain little of what they learn after even a few weeks.  Students rarely can apply what they have learned to the unpredictable problems of life and work. Students get little practice in developing their thinking skills and intellectuality or framing problems that interest them. As a result, students come to see learning as something grim to be avoided.

Problem based learning gives you opportunities to examine and try out what you already know; discover what you need to learn; develop your people skills for achieving higher performance in teams; improve your writing and speaking abilities, to state and defend with sound arguments and evidence your own ideas; and to become more flexible in your approach to problems that surprise and dismay others. Despite the work and effort it requires, PBL is never dull and is often fun.

Here is a diagram of the basic difference between subject based and problem based learning.






What is expected in Problem Based Learning?


According to the epistemological literature four types of knowledge can be identified.


  • 1     Explanatory knowledge-Theories
  • 2.       Descriptive Knowledge-Facts
  • 3.       Procedural Knowledge-Knowledge of how to do things
  • 4.       Subjective Knowledge- Personal convictions or attitudes of the learner

The PBL problems are in two varieties with regards to acquisition of above mentioned aspects of knowledge.

  • 1.       During the course of their study, students acquire different kinds of, or categories of knowledge about relevant aspects of their domain of study.
  • 2.       The problem types to be distinguished are meant to guide the learners towards these different knowledge categories.


In a problem based curricula four different kinds of problems have been identified.


  • ·         Explanation problems
  • ·         Fact-finding problems
  • ·         Strategy problems
  • ·         Moral dilemma resolution problems



Respectively they are effective in achieving explanatory knowledge, descriptive knowledge, procedural knowledge and subjective knowledge. Teacher, Mentor, or Guiding body has the freedom of designing the problems to drive learners to achieve the desired aspect of knowledge. Ideally it should be the combinations of all.

Characteristics of PBL


According to Barrows in 1996 there are six core characteristics of PBL are distinguished.


  • The first characteristic is that learning needs to be student-centred.
  • Second, learning has to occur in small student groups under the guidance of a tutor.
  • The third characteristic refers to the tutor as a facilitator or guide.
  • Fourth, authentic problems are primarily encountered in the learning sequence, before any preparation or study has occurred.
  • Fifth, the problems encountered are used as a tool to achieve the required knowledge and the problem-solving skills necessary to eventually solve the problem.
  • Finally, new information needs to be acquired through self-directed learning.


It is generally recognized that a seventh characteristic should be added: Essential for PBL is that students learn by analysing and solving representative problems. However authors also describes following features as essential components in PBL as well.

Students must have the responsibility for their own learning. The tutor is only a facilitator in this learning process.

The problem simulations used in problem-based learning must be ill-structured and allow for free inquiry. The real world problems are ill-structured and PBL should allow the trainers to develop their skill to identify the problem and develop realistic solutions.

Learning should be integrated from a wide range of disciplines or subjects. During PBL students should be able to access, study and integrate information from all the disciplines and reach to a more robust solution. The development of information systems and multidisciplinary approach in the present world support this task more than ever before.

Collaboration is essential. PBL provides the platform to share information and work productively with fellow people.

What students learn during their self-directed learning must be applied back to the problem with reanalysis and resolution.

A closing analysis of what has been learned from work with the problem and a discussion of what concepts and principles have been learned are essential.

Self and peer assessment should be carried out at the completion of each problem and at the end of every curricular unit.

The activities carried out in problem-based learning must be those valued in the real world.

Student examinations must measure student progress towards the goals of problem-based learning.

“Problem-based learning must be the pedagogical base in the curriculum and not part of a didactic curriculum.”

Rules in problem design



  • ·         Problem should consist of a title
  • ·         Well-formed problem consist of a concrete body text
  • ·         Each problem needs and instruction as to what to do with it
  • ·         A problem should be connected to the prior knowledge base students have
  • ·         A problem should raise students curiocity
  • ·         A problem should only introduce a limited number of issues for learning
  • ·         A problem should not take too much self-directed study time to acquire a fair understanding of the issues at hand


Advantages and Disadvantages of PBL


As in any educational theory there are advantages and limitations found in literature when creating or implementing problem based learning curriculum. Some of the advantages which were perceived by several authors are as follow.


  • ·        Students interest and benefit
  • ·        Minimizing faculty workload
  • ·        Long-term knowledge retention
  • ·        PBL provide a more challenging
  • ·        Motivating and enjoyable approach to education
  • ·        Students become actively engaged in meaningful learning rather than traditional memorization
  • ·        Increased responsibility for their learning and self-direction



Higher levels of comprehension and skill development occur than in traditional instruction and develop interpersonal collaboration and team work.


Following disadvantages has been encountered in PBL according to literature.


 Lack of systematic learning as in traditional learning in which the information is delivered in a well arranged manner


Difficulty in allocating time required in a course schedule


Students often express difficulties with self-directed learning whereas the teachers may have difficulties to break their traditional teaching habits.


Also selecting the appropriate question will be critical and challenging too.


However the traditional student assessment systems should be changed in assessing a student who was trained on PBL.

P    PBL makes a fundamental shift--from a focus on teaching to a focus on learning. The process is aimed at using the power of authentic problem solving to engage students and enhance their learning and motivation. There are several unique aspects that define the PBL approach:
  • Learning takes place within the contexts of authentic tasks, issues, and problems--that are aligned with real-world concerns.
  • In a PBL course, students and the instructor become colearners, coplanners, coproducers, and coevaluators as they design, implement, and continually refine their curricula.
  • The PBL approach is grounded in solid academic research on learning and on the best practices that promote it. This approach stimulates students to take responsibility for their own learning, since there are few lectures, no structured sequence of assigned readings, and so on.
  • PBL is unique in that it fosters collaboration among students, stresses the development of problem solving skills within the context of professional practice, promotes effective reasoning and self-directed learning, and is aimed at increasing motivation for life-long learning.
Problem-based learning begins with the introduction of an ill-structured problem on which all learning is centered. The problem is one that MBA students are likely to face as future professionals. Expertise is developed by engaging in progressive problem solving. Thus, problems drive the organization and dynamics of the course. MBA students, individually and collectively, assume major responsibility for their own learning and instruction. Most of the learning occurs in small groups rather than in lectures. As teacher, my role changes from "sage on stage" to a "guide by the side." My role is more like that of a facilitator and coach of student learning, acting at times as a resource person, rather than as knowledge-holder and disseminator. Similarly, your role, as a student, is more active, as you are engaged as a problem-solver, decision-maker, and meaning-maker, rather than being merely a passive listener and note-taker.

Where Did PBL Come From and Who Else is Using It?
PBL originated from a curriculum reform by medical faculty at Case Western Reserve University in the late 1950s. Innovative medical and health science programs continued to evolve the practice of PBL, particularly the specific small group learning and tutorial process that was developed by medical faculty at McMaster University in Canada. These innovative and forward-looking medical school programs considered the intensive pattern of basic science lectures followed by an equally exhausting clinical teaching program to be an ineffective and dehumanizing way to prepare future physicians. Given the explosion of medical information and new technology, as well as the rapidly changing demands of future medical practice, a new mode and strategy of learning was developed that would better prepare students for professional practice. PBL has spread to over 50 medical schools, and has diffused into many other professional fields including law, economics, architecture, mechanical and civil engineering, as well as in K-12 curricula. And the entire MBA program at Ohio University has been designed as an integrated curriculum using the PBL approach.

Why PBL?
Traditional education practices, starting from kindergarten through college, tend to produce students who are often disenchanted and bored with their education. They are faced with a vast amount of information to memorize, much of which seems irrelevant to the world as it exists outside of school. Students often forget much of what they learned, and that which they remember cannot often be applied to the problems and tasks they later face in the business world. Traditional classrooms also do not prepare students to work with others in collaborative team situations. The result: students tend to view MBA education as simply a "right of passage," a necessary "union card," and an imposed set of hurdles with little relevance to the real world. Education is reduced to acquiring a diploma (merely another commodity to be purchased in the marketplace), and the final grade becomes the overriding concern (rather than learning).
Research in educational psychology has found that traditional educational approaches (e.g., lectures) do not lead to a high rate of knowledge retention. Despite intense efforts on the part of both students and teachers, most material learned through lectures is soon forgotten, and natural problem solving abilities may actually be impaired. In fact, studies have shown that in 90 days students forget 90% of everything they have been told (Smilovitz, 1996). Motivation in such traditional classroom environments is also usually low.
Perhaps one of the greatest advantages of PBL is that students genuinely enjoy the process of learning. PBL is a challenging program which makes the study of organization design and change intriguing for students because they are motivated to learn by a need to understand and solve real managerial problems. The relevance of information learned is readily apparent; students become aware of a need for knowledge as they work to resolve the problems.

How Does PBL Work?
A PBL course is designed into a series of real-world, hands-on, PBL investigations. You will be working in small groups/teams with other students on problems that you are likely to encounter as a professional manager. You will begin a PBL investigation by being presented with an ill-structured organizational problem or scenario. Such a presentation may be in the form of a written statement, a video clip of a real manager at a company, or a guest speaker. Every PBL team will appoint a chairperson/leader and sometimes a recorder/secretary. Your PBL team will be guided in the use of a reiterative problem-solving process. Your team will applyy this problem solving process to find, analyze, and solve the presenting problem. Some PBL investigations may culminate in a student-created project/product, exhibitions, or other artifacts that address the driving questions. In some cases, the PBL investigation will culminate in an oral performance with managers from the business community in attendance.
As you work with each problem you can:
  1. Develop your diagnostic reasoning and analytical problem-solving skills.
  2. Determine what knowledge you need to acquire to understand the problem, and others like it.
  3. Discover the best resources for acquiring that information.
  4. Carry out your own personalized study using a wide range of resources.
  5. Apply the information you have learned back to the problem.
  6. Integrate this newly acquired knowledge with your existing understanding.
In short, you will be learning in a highly relevant and exciting manner to problem-solve and to develop self-directed study skills that build toward the skills and knowledge that you will need as a practicing manager.
The problem-solving process can be summarized according to three broad and reiterative phases.
Phase 1. First, your group will gather information and list it under a heading entitled: "What do we already know?" In this phase, you will entertain the problem in light of the knowledge that you already have from your own experience. Your group will discuss the current situation surrounding the problem as it has been presented. This analysis requires discussion and agreement on the working definitions of the problems, and sorting out which issues and aspects of the situation are worthy of further investigation. This initial analysis should yield a problem statement that serves as a starting point for the investigation, and it may be revised as assumptions are questioned and new information comes to light.
Phase 2. Next, you will engage with the problem by also identifying under a second heading, "What do we need to know (to solve this problem)?" Here you will list questions or learning issues that must be answered to address missing knowledge, or to shed light on the problem. It is in this phase that your group will be analyzing the problem into components, discussing implications, entertaining possible explanations or solutions, and developing working hypotheses. This activity is like a "brainstorming" phase with evaluation suspended while explanations or solutions are written on a flipchart or chalkboard. Your group will need to formulate learning goals, outlining what further information is needed, and how this information can best be obtained.
Phase 3. The above list should inform your group in what to do in order to solve the problem. In this phase your group will discuss, evaluate, and organize hypotheses and tentative hypotheses. Your group will make a "What should we do?" list that formulates keeps track of such issues as what resources to consult, people to interview, articles to read, and what specific actions team members need to perform. It is in this phase that your group will identify and allocate learning tasks, develop study plans to discover needed information. You will be gathering information from the classroom, resource readings, texts, library sources, videos, and from external experts on the subject. As new information is acquired, your group will need to meet to analyze and evaluate it for its reliability and usefulness in applying it to the problem.
In short, you will be spending a great deal of time discussing the problem, generating hypotheses, identifying relevant facts, searching for information, and defining their own learning issues. Unlike traditional and standard classes, learning objectives are not stated up front. Rather, you and members of your group will be responsible for generating your own learning issues or objectives based on your group's analysis of the problem.
All during this process, as a student, you will be actively defining and constructing potential solutions. As an instructor, my role is primarily to model, guide, coach--to support you and your team through the learning and assessment process.
The majority of class time will be devoted to working in self-directed, PBL small group tutorials. A portion of class time will be allocated to "Resource Sessions," which may include simulations, case studies, and brief discussions to further explore concepts and issues which arise out of the PBL projects.

Transitioning to a PBL Classroom Environment
Students who are new to a PBL classroom environment may find it initially unsettling. This is because you are being asked to take responsibility for your own learning, to work on ill-structured problems where there isn't a pre-established "right answer," and where you are expected to structure your own approach to acquiring and using information to solve problems. In many respects, this environment mimics the "real-world." In business settings, there are no standardized objective tests, lectures, or routine and well defined assignments. Entering this new type of learning environment requires you a willingness on your part to accept risk and uncertainty, and to become a self-directed learner.

Establishing an Open Climate for PBL
Establishing an open climate is essential for problem-based learning. Every student should feel free to say whatever comes to mind, any ideas or comments, no matter how unsophisticated or inappropriate they might seem, without being put down or criticized. Most students have learned in their prior educational experiences not to speak up or volunteer their thoughts unless they are absolutely sure of the answer. Any show of ignorance was held against them.
Learning can never occur unless you can bring out their ideas and thoughts, and openly admit to confusion, lack of understanding, or ignorance…"I don't know" is a powerful first step to learning. The same is true for myself as the instructor. The instructor doesn't have all the answers or know everything; no one person can be an authority in everything, and no one should be expected to have all the answers. We can ALL learn in this course.
It is your responsibility, as a student, TO SPEAK UP when you are doubtful, unsure, or uncomfortable with comments or ideas made by others in the group. You also must be willing to speak up when you feel that another member of your group is making statements that you feel are incorrect.
Students must also develop the ability to openly and constructively express their opinions about the comments or ideas of others, or about the quality of other students' performance in the group. It is your responsibility to offer opinions in a friendly and constructive manner. Every student must learn to both give and accept constructive criticism.

PBL Assessment Philosophy

To Assess. The Latin origin of this term, assidere, literally means to sit down beside. Another way of thinking of assessment is to use careful judgment based on the kind of close observation that comes from "sitting down beside."
With PBL, assessment is not separate from instruction. Rather, assessment is integral to learning. The focus and purpose of assessment is on learning, on how it is done, and how it can be better, not on normative comparisons. Assessment is a continuous process that drives instruction. Further, assessment does not bring an end to learning; it provides information about how to continue to develop your skills, knowledge and abilities with respect to the course learning objectives. Having said this, it is important for you to think of assessment as an active demonstration of your understanding and ability to apply this understanding.
Words like "tests" and "examinations" have well established connotations of evalutating a student's possession of knowledge. We need a different process, and a new language, to identify how to assess a student's capability for using and applying knowledge. Education of an individual, understood in terms of developing a capbility for using and applying one's knowledge, cannot be adequately assessed by traditional testing. Grading on a curve, which sorts students into groups for administrative purposes, says nothing about how each student is using his or her talents or growing toward their potential.
With PBL, the instructor is no longer the sole yardstick by which your progress will be measured. Rather, my role as instructor is to help students monitor themselves, to monitor your own progress, to establish criteria for learning and quality work, and to help you devise your own goals for improvement. This means that I will not be the only judge of student work; students will learn to evaluate the work of their peers, as well as their own. In addition, your work may also be monitored and evaluated by real-world assessors--managers and executives from companies in the Bay Area.
Students will codevelop with the instructor relevant and meaningful assessments, and play an active role in developing criteria and setting standards of performance for high quality work. Assessments must have meaning for the learner. For assessments to be meaningful, they must have some connection to the real world, difficult enough to be interesting but not totally frustrating, and generative, where a real product, service, or valued information is being evaluated. This concept of assessment-as-learning focuses on what learners achieve--not what teachers provide.
Therefore, in this course, student assessment is a multidimensional process, integral to learning, that involves observing performances of individual learners in action and judging them on the basis of collaboratively determined developmental criteria, with resulting feedback to that learner. Assessments may involve a performance or demonstration, usually for a real audience (i.e., managers from the business community) and useful purpose (e.g., as part of student exhibition or learning conference). Assessment must be seamless and ongoing; it must be part of the PBL process. Students must also learn during assessment; it is not simpy a "grade" that is tacked on at the end of a paper or transcript.
In general, and at minimum, students will be assessed in three broad areas:
  1. Applied Competence. Demonstrate the ability to use organizational design and change management concepts and frameworks to identify and anaylze variables that can influence an organization's overall effectiveness.
  2. Critical Thinking, Problem-Solving and Communicative Competence. Identify problems and/or opportunities in organizational contexts and make specific recommendations, supported by theory, to improve the situation. Accurately and competently using theoretical frameworks from organization design and change literature to interpret and solve business problems, and effectively communicating your analyses to others in a variety of professional contexts. Implementing your problem solving activities with a commitment to quality.
  3. Collaborative and Leadership Competence. Collaborates as a member of a project team, taking the initiative in identifying and solving problems or pursuing opportunities for learning and improvement within your group.

Assessment must also be seen as fair and equitable. In the early part of the semester, a voluntary "student assessment task force" will be formed. This task force will consists of student representatives from each of the three sections of MGMT 842 and will work with the instructor in developing an overall assessment plan for all three sections. After every PBL project, group-based assessments will be conducted. These assessments are to help facilitate reflection on what you learned during the PBL project, and to receive direct feedback from your team members on your performance, contributions, and intellectual achievements.





Summary

PBL has becoming a revolutionary method of leaning in the context of student centred learning. At the heart of PBL stands a problem. PBL process can be designed in the way the students achieve the different aspects of knowledge. As in any learning method PBL also has its own advantages and disadvantages.

ஐன்ஸ்டீனின் "எம் கோட்பாடு" - M-theory, the theory formerly known as Strings

M-theory, the theory formerly known as Strings

The Standard Model


In the standard model of particle physics, particles are considered to be points moving through space, tracing out a line called the World Line. To take into account the different interactions observed in Nature one has to provide particles with more degrees of freedom than only their position and velocity, such as mass, electric charge, color (which is the "charge" associated with the strong interaction) or spin.
The standard model was designed within a framework known as Quantum Field Theory (QFT), which gives us the tools to build theories consistent both with quantum mechanics and the special theory of relativity. With these tools, theories were built which describe with great success three of the four known interactions in Nature: Electromagnetism, and the Strong and Weak nuclear forces. Furthermore, a very successful unification between Electromagnetism and the Weak force was achieved (Electroweak Theory), and promising ideas put forward to try to include the Strong force. But unfortunately the fourth interaction, gravity, beautifully described by Einstein's General Relativity (GR), does not seem to fit into this scheme. Whenever one tries to apply the rules of QFT to GR one gets results which make no sense. For instance, the force between two gravitons (the particles that mediate gravitational interactions), becomes infinite and we do not know how to get rid of these infinities to get physically sensible results.

String Theory

In String Theory, the myriad of particle types is replaced by a single fundamental building block, a `string'. These strings can be closed, like loops, or open, like a hair. As the string moves through time it traces out a tube or a sheet, according to whether it is closed or open. Furthermore, the string is free to vibrate, and different vibrational modes of the string represent the different particle types, since different modes are seen as different masses or spins.
One mode of vibration, or `note', makes the string appear as an electron, another as a photon. There is even a mode describing the graviton, the particle carrying the force of gravity, which is an important reason why String Theory has received so much attention. The point is that we can make sense of the interaction of two gravitons in String theory in a way we could not in QFT. There are no infinities! And gravity is not something we put in by hand. It has to be there in a theory of strings. So, the first great achievement of String Theory was to give a consistent theory of quantum gravity, which resembles GR at macroscopic distances. Moreover String Theory also possesses the necessary degrees of freedom to describe the other interactions! At this point a great hope was created that String Theory would be able to unify all the known forces and particles together into a single `Theory of Everything'.

From Strings to Superstrings

The particles known in nature are classified according to their spin into bosons (integer spin) or fermions (odd half integer spin). The former are the ones that carry forces, for example, the photon, which carries electromagnetic force, the gluon, which carries the strong nuclear force, and the graviton, which carries gravitational force. The latter make up the matter we are made of, like the electron or the quark. The original String Theory only described particles that were bosons, hence Bosonic String Theory. It did not describe Fermions. So quarks and electrons, for instance, were not included in Bosonic String Theory.
By introducing Supersymmetry to Bosonic String Theory, we can obtain a new theory that describes both the forces and the matter which make up the Universe. This is the theory of superstrings. There are three different superstring theories which make sense, i.e. display no mathematical inconsistencies. In two of them the fundamental object is a closed string, while in the third, open strings are the building blocks. Furthermore, mixing the best features of the bosonic string and the superstring, we can create two other consistent theories of strings, Heterotic String Theories.
However, this abundance of theories of strings was a puzzle: If we are searching for the theory of everything, to have five of them is an embarrassment of riches! Fortunately, M-theory came to save us.

Extra dimensions...

One of the most remarkable predictions of String Theory is that space-time has ten dimensions! At first sight, this may be seen as a reason to dismiss the theory altogether, as we obviously have only three dimensions of space and one of time. However, if we assume that six of these dimensions are curled up very tightly, then we may never be aware of their existence. Furthermore, having these so-called compact dimensions is very beneficial if String Theory is to describe a Theory of Everything. The idea is that degrees of freedom like the electric charge of an electron will then arise simply as motion in the extra compact directions! The principle that compact dimensions may lead to unifying theories is not new, but dates from the 1920's, since the theory of Kaluza and Klein. In a sense, String Theory is the ultimate Kaluza-Klein theory.
For simplicity, it is usually assumed that the extra dimensions are wrapped up on six circles. For realistic results they are treated as being wrapped up on mathematical elaborations known as Calabi-Yau Manifolds and Orbifolds.

M-theory

Apart from the fact that instead of one there are five different, healthy theories of strings (three superstrings and two heterotic strings) there was another difficulty in studying these theories: we did not have tools to explore the theory over all possible values of the parameters in the theory. Each theory was like a large planet of which we only knew a small island somewhere on the planet. But over the last four years, techniques were developed to explore the theories more thoroughly, in other words, to travel around the seas in each of those planets and find new islands. And only then it was realized that those five string theories are actually islands on the same planet, not different ones! Thus there is an underlying theory of which all string theories are only different aspects. This was called M-theory. The M might stand for Mother of all theories or Mystery, because the planet we call M-theory is still largely unexplored.

There is still a third possibility for the M in M-theory. One of the islands that was found on the M-theory planet corresponds to a theory that lives not in 10 but in 11 dimensions. This seems to be telling us that M-theory should be viewed as an 11 dimensional theory that looks 10 dimensional at some points in its space of parameters. Such a theory could have as a fundamental object a Membrane, as opposed to a string. Like a drinking straw seen at a distance, the membranes would look like strings when we curl the 11th dimension into a small circle.

Black Holes in M-theory

Black Holes have been studied for many years as configurations of spacetime in General Relativity, corresponding to very strong gravitational fields. But since we cannot build a consistent quantum theory from GR, several puzzles were raised concerning the microscopic physics of black holes. One of the most intriguing was related to the entropy of Black Holes. In thermodynamics, entropy is the quantity that measures the number of states of a system that look the same. A very untidy room has a large entropy, since one can move something on the floor from one side of the room to the other and no one will notice because of the mess - they are equivalent states. In a very tidy room, if you change anything it will be noticeable, since everything has its own place. So we associate entropy to disorder. Black Holes have a huge disorder. However, no one knew what the states associated to the entropy of the black hole were. The last four years brought great excitement in this area. Similar techniques to the ones used to find the islands of M-theory, allowed us to explain exactly what states correspond to the disorder of some black holes, and to explain using fundamental theory the thermodynamic properties that had been deduced previously using less direct arguments.
Many other problems are still open, but the application of string theory to the study of Black Holes promises to be one of the most interesting topics for the next few years.
ஐன்ஸ்டைனின் ஒருங்கமைக் கோட்பாட்டின் (Theory of Everything) அடிப்படையில், அதன் நீட்சியாக
உருவாக்கப்பட்டது 'அதிர்விழைக்
கோட்பாடு' (String Theory) . இந்த
அதிர்விழைக் கோட்பாட்டின் நீட்சியாக 'எம் கோட்பாடு' (M Theory) உருவாகியது.


அதிர்விழைக் கோட்பாட்டையும், எம்
கோட்பாட்டையும் நிரூபிப்பதற்கான
வாய்ப்புகள் அதை
உருவாக்கியவர்களுக்குக்
கிடைக்கவில்லை. அந்தக் கோட்பாடுகள்
பல விஞ்ஞானிகளால்
விமர்சனத்துக்குள்ளாகியது.
கற்பனாவாதிகள் என்று சிலரால்
ஏளனமும் செய்யப்பட்டது. ஆனால், அந்தக் கோட்பாட்டைப் பலர் ஏற்றுக்
கொண்டுமிருக்கிறார்கள்.
அதிர்விழைக் கோட்பாடு, எம்
கோட்பாடுகளின்படி, நாம் வாழும்
அண்டத்திற்கு மொத்தமாகப் பனினொரு
பரிமாணங்கள் உள்ளன என்று
நிறுவப்பட்டிருக்கின்றது. மனிதர்களான
நம்மால் அதிகபட்சமாக மூன்றே மூன்று
பரிமாணங்களைத்தான் புரிந்து கொள்ள
முடியும். நீளம், அகலம், உயரம் (X,Y,Z,)
என்பவையே அந்த மூன்று
பரிமாணங்களுமாகும். நம் கண்ணால்
பார்க்கும் காட்சிகளெல்லாம்
முப்பரிமாண வடிவங்களாலானவை.
மனிதன் மூன்று பரிமாணத்தில்
வாழ்ந்து கொண்டிருக்கிறான். ஆனால்,
ஒரு பரிமாணத்தில் வாழும்
உயிரினங்களும், இரு பரிமாணங்களில்
வாழும் உயிரினங்குகளும் பூமியில்
இருக்கின்றன. உதாரணமாக நிலத்தில்
அசையாமல் இருக்கும் ஒரு சிறிய புல்
ஒரு பரிமாணத்தில் வாழ்வதாகவே நாம்
எடுத்துக் கொள்ளலாம். அதற்கு, இடம்
வலமாகவோ, முன் பின்னாகவோ
அசைவதற்கான பரிமாணம் இல்லை.
ஆனால் கீழ் மேலாக அது தன்னை
வளர்த்துக் கொள்கிறது. அதனால் அதை
ஒரு பரிமாணத்தில் வாழும்
உயிரினமாகக் கொள்ளலாம்.
இது ஒரு உதாரணத்திற்கு மட்டுமே.
அதுபோல, நிலத்தில் ஊர்ந்து செல்லும்
எறும்பொன்றை இரு பரிமாணங்களில்
வாழும் உயிரினமாகக் கொள்ளலாம்.
எறும்பு, முன் பின்னாகவும், இடம்
வலமாகவும் அசைகிறது. ஆனால்,
அதனால், மேல் கீழாக அசைய
முடிவதில்லை. ஆனால், ஒரு
பறவையால் இடம் வலம், முன் பின், மேல் கீழ் ஆகிய மூன்று பரிமாணங்களில்
பயணிக்க முடிகிறது.

ஒரு எறும்பிடம்"மூன்றாவது பரிமாணமென்ற ஒன்று

உண்டென்றும், அங்கு மனிதன்
என்பவனும், பறவைகளும் வாழ்ந்து
கொண்டிருக்கின்றன என்றும்
சொன்னால், அதனால் அதைக்
கற்பனையே செய்து பார்க்க
முடியாது. அதுபோல, நான்காவது
பரிமாணம் உண்டென்று மனிதனிடம்
சொன்னால், அவனாலும் அதை நம்ப
முடிவதில்லை. கற்பனை செய்யவும்
முடிவதில்லை.
எம் கோட்பாடு, மொத்தமாகப் பதினோரு பரிமாணங்கள் உள்ளன என்று சொல்கின்றது. இதுஉண்மையாக இருக்கும் பட்சத்தில் நான்காவது, ஐந்தாவது, ஆறாவது, ஏழாவது, எட்டாவது, ஒன்பதாவது, பத்தாவது, பதினோராவது பரிமாணங்களிலும் வெவ்வேறு வகையான உயிரினங்கள்
வாழ்ந்துகொண்டிருக்கலாம். அவையே
ஆவிகளாகவும், பேய்களாகவும்,
ஏலியன்களாகவும், அசுரர்களாகவும்,
தேவர்களாகவும், கடவுள்களாகவும்
இருக்கலாம்.
ஒவ்வொரு பரிமாணங்களாக
அதிகரிக்க அதிகரிக்க, அதில் வாழும்
உயிரினங்களின் சக்திகளும்
அதிகரித்துச் செல்லலாம். மூன்று
பரிமாணங்களைவிட அதிகப்
பரிமாணங்கள் உண்டென்று
நிரூபிக்கப்பட்டால், அதில் வேறு
வகையான உயிரினங்களும்
வாழ்வதற்குச் சாத்தியங்களும் உண்டு
என்பதும் உறுதியாகும்....

Sex differences in senescence: the role of intra-sexual competition in early adulthood


Christopher Beirne, Richard Delahay, Andrew Young
Abstract
Males and females frequently differ in their rates of ageing, but the origins of these differences are poorly understood. Sex differences in senescence have been hypothesized to arise, because investment in intra-sexual reproductive competition entails costs to somatic maintenance, leaving the sex that experiences stronger reproductive competition showing higher rates of senescence. However, evidence that sex differences in senescence are attributable to downstream effects of the intensity of intra-sexual reproductive competition experienced during the lifetime remains elusive. Here, we show using a 35 year study of wild European badgers (Meles meles), that (i) males show higher body mass senescence rates than females and (ii) this sex difference is largely attributable to sex-specific downstream effects of the intensity of intra-sexual competition experienced during early adulthood. Our findings provide rare support for the view that somatic maintenance costs arising from intra-sexual competition can cause both individual variation and sex differences in senescence.
Author Christopher Beirne from the Centre for Ecology and Conservation at the University of Exeter's Penryn Campus in Cornwall said: "The study shows that when male badgers don't have to fight for a mate, they can prioritise their health and wellbeing and as a result they age more slowly. However, when badgers fight a lot in their youth, they really pay for it by ageing rapidly in later life."
Unlike the males, female badgers appeared to be unaffected by the density of other females in the area, indicating that they don't suffer from the effects of competition in the same way as males.
Co-author Dr Andrew Young from the University of Exeter said: "The findings are particularly interesting because males age faster than females in many species, including our own, but we don't really understand why. Our findings suggest that malebadgers age faster than females because of the male-male competition that they experience during their lifetimes; males that experience strong competition age more quickly than females, while males that experience little competition do not."

Read more at: http://phys.org/news/2015-07-strain-competitive-males-age-faster.html#jCp

காணக் கிடைக்காத திருப்பதி ஏழுமலையானின் தரிசனம்


Tuesday, July 7, 2015

The Medical Model, Pathology and Pharmacology

Why, in Western psychology, have we been so focused on the dark side of human nature? Even before Freud, Western psychology was based on a medical model, and it still focuses primarily on pathology. The psychiatric profession’s Diagnostic and Statistical Manual of Mental Disorders, which orients the work of most therapists, clinics and health care providers, is a comprehensive listing of hundreds of psychological problems and diseases. Categorizing problems helps us study them and then, it is hoped, cure them in the most scientific and economically efficient way. But often we give so much attention to our protective layers of fear, depression, confusion, and aggression that we forget who we really are.
As a teacher, I see this all the time. When a middle-aged man named Marty came to see me after a painful separation and divorce, he was caught in the repetitive cycles of unworthiness and shame that he had carried since childhood. he believed that there was something terribly wrong with him. He had forgotten his original goodness. When a young woman, Jan, came to Buddhist practice after a long struggle with anxiety and depression, she had a hard time letting go of her self-image as a broken and damaged person. For years she had seen herself only through her diagnosis and the various medications that had failed to control it.
As psychology becomes more pharmacologically oriented, this medical model is reinforced. Today, most of the millions of adults seeking mental health support are quickly put on medication. Even more troubling, hundreds of thousands of children are being prescribed powerful psychiatric drugs for conditions ranging from attention-deficit/hyperactivity disorder (ADHD) to the newly popular diagnosis of childhood bipolar disorder. While these medications may be appropriate, even lifesaving, in some cases laypeople and professionals increasingly look for a pill as the answer to human confusion and suffering. It need not be so.’
Jack Kornfield