« brain specimens. . Principles of Brain Organization The human brain contains approximately 1011 nerve cells or neurons. In general ...» Document abstract
$1.95
2 word format
Language : english
psychology
research papers
date published
13/11/2007
review : not yet assessed
level : Advanced
requested 5 times
SummaryThe human brain contains approximately 1011 nerve cells or neurons. In general, neurons are composed of four morphologically identified regions: (1) the cell body or soma, which contains the nucleus and can be considered the metabolic center of the neuron; (2) the dendrites, processes that arise from the cell body, branch extensively, and serve as the major recipient zones of input from other neurons; (3) the axon, a single process that arises from a specialized portion of the cell body (the axon hillock) and conveys information to other neurons; and (4) the axon terminals, fine branches near the end of the axon that form contacts (synapses) generally with the dendrites or the cell bodies of other neurons, release neurotransmitters, and thereby provide a mechanism for interneuronal communication.
Table of Contents- The majority of neurons in the human brain are considered to be multipolar in that they give rise to a single axon and several dendritic processes.
- In addition to neurons, the brain also contains several types of glial cells, which are at least ten times more numerous than the neurons.
- Other types of histological techniques, such as silver stains, selectively label the myelin coating of axons and, consequently, reveal the myeloarchitecture of the brain.
- Within the adult brain the connections among neurons or neural circuits follow several important principles of organization.
- Third, the connections among regions may be organized in a hierarchical or parallel fashion or both.
- The expansion and the differentiation of the human brain is associated with substantial differences in the organization of certain elements of neural circuitry.
- An additional limitation to the study of the human brain concerns the changes in morphology and biochemistry that can occur during the interval between the time of death and the freezing or fixation of brain specimens.
« that inositol levels in brain are unaffected by the flexibility inherent in the organization of intraneuronal has revealed its operating principles in great ...» Document abstract
$6.95
7 word format
Language : english
biology
research papers
date published
26/11/2007
review : not yet assessed
level : Advanced
requested 0 times
SummaryPrior to delineating the organization of specific intraneuronal signaling pathways, it is important to consider, in general terms, their role in helping neurons interpret and respond to the barrage of afferent stimulation impinging on them continuously. From an evolutionary perspective, second messenger systems predate neurotransmitters and neurotrophins, examples of first messengers detected by cell surface receptors. Before the advent of neurotransmitters, prokaryotic organisms relied on cyclic adenosine monophosphate (cAMP) and other intracellular signaling pathways to coordinate diverse responses located in disparate parts of these unicellular organisms to changes in ambient nutrients or conditions. Neurotransmitters and neurotrophins have evolved subsequently to take advantage of these internal signaling pathways that have undergone a parallel growth process.
Table of Contents- Intraneuronal signaling pathways do more than merely enlarge the sphere of influence of afferent stimuli beyond the local environment of the cell surface receptor.
- Although the overwhelming majority of psychiatric drugs target extracellular receptors or uptake sites, the explosion of information on intraneuronal signaling pathways suggests that these may represent suitable drug targets.
- Psychiatrists have long been taught that a true understanding of normal and abnormal behavior requires an appreciation of the interplay of forces lurking beneath the surface.
- Neurotransmitter receptors may couple to adenylate cyclase via different classes of G proteins, referred to as Gs or Gi, depending on whether they stimulate or inhibit cyclic AMP formation.
- Cyclic GMP Besides cyclic AMP, another cyclic nucleotide, cyclic guanosine monophosphate (GMP) has been identified as a second messenger regulated by neurotransmitter receptor stimulation.
- Because the effects of cAMP are mediated to a large extent via activation of a kinase, it was generally assumed that each of these second messengers acted in a similar fashion.
- However, this view has been challenged recently in light of animal studies demonstrating that inositol levels in brain are unaffected by lithium concentrations within its therapeutic range.
- These alternate arrangements emphasize the notion that intracellular signaling cascades have evolved in ways that heighten their versatility, with each of the components having multiple signaling capacities.
- Another family of tyrosine kinases has been identified that differs from the receptor tyrosine kinases in that it contains only the cytoplasmic domain.
- Cross-Talk Among Signaling Pathways The organization of intraneuronal signaling pathways allows for a high degree of interaction or cross-talk among pathways
« compete and differentiate within the brain and create an Three principles are relevant to psychiatry and include to move the system towards self-organization. ...» Document abstract
$7.95
8 word format
Language : english
psychology
research papers
date published
13/11/2007
review : not yet assessed
level : Advanced
requested 0 times
SummaryThe vast majority of mental processes are outside of conscious awareness. These processes can impact thinking, feeling, and behavior despite the lack of conscious awareness. Consciousness can be thought to include two elements: awareness and sentience, the quality of the experience. Each form of consciousness has intrigued philosophers and scientists for many years and various theories have been proposed to explain these phenomena. Little is known about the basic mechanisms that underlie the sentient experience of consciousness. Phenomenal awareness has been the focus of active research and has yielded some basic ideas about the role of consciousness in cognition. One essential issue is that the effective processing of mental representations does not require conscious awareness. However, the intentional, strategic alteration in patterns of processing may necessitate the involvement of consciousness in order to achieve a new outcome. Thus, consciousness is not required for most processes, but its involvement allows for a qualitatively different result in representational transformations. One example of this is in memory processing in which explicit memory requires focal, conscious attention or awareness in order to encode events into explicit form. Such representations are later available for conscious retrieval when they can be examined and transformed for intentional purposes, such as the recollection of facts or autobiographical knowledge.
Table of Contents- Based on a biological assessment of brain function, Gerald Edelman's theory describes two forms of consciousness that derive from the resonant interactions between groups of neurons.
- Misidentification syndromes are other examples of subjective, conscious experience disturbances.
- Many psychiatric disturbances may thus involve alterations in the experience of conscious awareness and sentience.
- Mental models are unconscious, highly organized structural processes that are derived from past experiences, that aid in interpreting present stimuli, and that influence the direction of future behavior.
- Thought, Language, and Cognition There is no universally accepted definition of thought.
- Psycholinguistics is a complex domain that focuses on the cognitive process of language formation and semantic analysis.
- Jerome Bruner has described the distinction between the earlier mode of thought, called narrative cognition, versus the later mode, which is the scientific, logical, paradigmatic mode.
- Discourse and Narrative Discourse is communication from one person to another; it is thought to involve a sense of intention or plan.
- Cognitive Development Developmental theories and research can be divided into several views.
- Psychiatric disturbances may be conceptualized as disturbances in self-organizational processes.
« Governments' immigration policies and principles on nationality aspects related to brain drain in International Organization for Migration, World Migration ...» Document abstract
$9.95
11 word format
Language : english
social sciences
presentation
date published
31/08/2006
review : not yet assessed
level : Expert
requested 6 times
SummaryImmigration is deeply rooted in the European history. In the post-war times several West European governments – especially in big and devastated countries – resorted to immigration to cope with important needs for labour force the after-reconstruction economic boom. Immigrants, mostly from Northern Africa and the Middle East, therefore belong to the origins of the European social model and immigration doubtlessly played a crucial role in its coming of age. The existence of a common social model to European countries will not be discussed here. Rather this concept shall refer to the Welfare State as an organizational model of production and work relationships, as well as to the typical social and political arrangement in Europe after 1945. But if it is one constituent of this model, why is the role of immigration in Europe questioned today? When trying to have European-wide glance at the problem, the term immigrants will refer here to non-EU citizens. It should also be distinguished between legal and illegal immigration, which are to relate to different economic and political problems. There are two categories of factors for immigration. On the one hand “push factors”, ie factors that lead people to leave their home country, are the most crucial: family reunification as most important, asylum seeking and work. On the other hand, “pull factors” attract people to go to certain countries: it is mainly a demand for labour force which leads governments to create incentives (delivering special visas) or employers to organize recruitment networks . Finally, the level of immigrant population in a country falls back on many dimensions that need to be taken into account: while it has a strong impact on the economy, it is also related to people’s identity, societal change and therefore has a strong political and electoral dimension. This paper will argue that while there is room for immigrants in Europe, the acceptable level of immigration depends on societies’ capacity to tackle the political problems related to it. In other words, the aim will be to highlight the trade-off between economic rationality and political issues facing decision-makers. This paper will try to provide for a comprehensive overview of the issue. However, the focus will be more on legal and work-related immigration than illegal immigration. The first section will explain why immigration can be seen as a chance for Europe and enlarge on the action undertaken by the EU in this area. The second section will argue, however, that many problematic political issues should be taken into consideration which undermine the relevance of the recourse to immigration for economic purposes.
Table of Contents- Immigration: a window of opportunity for greying Europe.
- The economic impact of a rapidly ageing population.
- The contrasted picture of immigration in Europe.
- The coming of age of a European immigration policy and the economic issue.
- Beyond the economic rationale, highly sensitive political issues.
- The limitations of the European immigration policy.
- The difficult search for an efficient integration model.
- Populism and xenophobia: a European-wide trend.
- Critical reflection on the EU immigration policy.
« He postulated that the organization of speech is a and the activity of regions in the brain that are Zipf believed that `our dynamical principles of speech ...» Document abstract
$9.95
59 word format
Language : english
linguistics
presentation
date published
27/07/2006
review : not yet assessed
level : Expert
requested 15 times
SummaryThe hypothesis of Zipf concerning a universal Principle of Least Effort, manifesting itself in Zipf ’s law and modeled by Ferrer i Cancho and Sol´e in a signal-object reference matrix, gave rise to the idea that maybe the elements
in music that elicit our emotional responses can be identified. The unde- niable relation between music and emotion was the reason to consider a possible signal-emotion reference system analogous to the signal-object ref- erence in natural human language. Following Zipf ’s line of reasoning, music
as an exponent of human behaviour is subject to the Principle of Least Effort and is consequently structured in such a way that the distribution pattern
of the signals that “communicate the musical message” follows a power law.
In this thesis the possibility to deploy the characteristics of the Zipf curve to gain more insight into the relation between music and emotion was investi- gated. From the elements that, viewed in the framework of a signal-emotion reference could qualify as the signals that elicit emotion, two were investi- gated, viz. notes and intervals. Experiments were performed on 18 single classical music pieces from 18 different composers and on a larger classical music corpus. Results indicate that intervals have a distribution pattern that comes closest to a Zipf curve, but neither data type exhibits a gen- uine Zipf distribution. Further research will be needed to decide whether the method that was applied could be a useful tool in the search for the elements that elicit emotion.
in music that elicit our emotional responses can be identified. The unde- niable relation between music and emotion was the reason to consider a possible signal-emotion reference system analogous to the signal-object ref- erence in natural human language. Following Zipf ’s line of reasoning, music
as an exponent of human behaviour is subject to the Principle of Least Effort and is consequently structured in such a way that the distribution pattern
of the signals that “communicate the musical message” follows a power law.
In this thesis the possibility to deploy the characteristics of the Zipf curve to gain more insight into the relation between music and emotion was investi- gated. From the elements that, viewed in the framework of a signal-emotion reference could qualify as the signals that elicit emotion, two were investi- gated, viz. notes and intervals. Experiments were performed on 18 single classical music pieces from 18 different composers and on a larger classical music corpus. Results indicate that intervals have a distribution pattern that comes closest to a Zipf curve, but neither data type exhibits a gen- uine Zipf distribution. Further research will be needed to decide whether the method that was applied could be a useful tool in the search for the elements that elicit emotion.
Table of Contents- Quantitative linguistics
- Frequency distributions
- Entropy
- Previous research
- Balancing effort
- Data types
- Corpus size
- Music and Zipf 's law
- Music and communication
- Music and emotion
- Research question
- Experimental setup
- Results
- The rank-frequency distribution of notes and intervals
« the sun's energy, and build a self-reflective brain. We will now examine these principles in more office manufacturer among the founders of the organization. ...» Document abstract
$9.95
29 word format
Language : english
ecology & environment
term papers
date published
12/02/2007
review : not yet assessed
level : Advanced
requested 87 times
SummaryIn March 2005, the UN released its Millennium Ecosystem Assessment , the first comprehensive scientific audit of the state of the planet. Completed over four years by 2,000 experts, the survey demonstrates that economic activity has destroyed 60% of the Earth’s life-supporting ecosystems, threatening humanity’s ability to sustain its standards of living. Thus, even though the Industrial Revolution has brought about a tremendous rise in the standards of living of most in the Western World, and although globalization is spreading this wealth to an increasing number of people in the developing world, a growing number of worrisome environmental trends suggest that our current economic model is not sustainable in the medium- to short- run.
Table of Contents- Why our current economic model is unsustainable
- Why eco-efficiency alone is not the solution
- How C2C draws on nature to fix our model
- How to apply C2C to product design
- C2C in action: Herman Miller and the Mirra' Chair
- C2C: the next industrial revolution?
- Exhibits
1
knowledge network
Sort by
Subject :
Type :
Extension :
Language :
Size :