Write a detailed note on plate tectonics of the Earth. Use diagrams related to the question.
Plate tectonics, theory dealing with the dynamics of Earth’s outer shell—the lithosphere—that revolutionized Earth sciences by providing a uniform context for understanding mountain-building processes, volcanoes, and earthquakes as well as the evolution of Earth’s surface and reconstructing its past continents and oceans.
The concept of plate tectonics was formulated in the 1960s. According to the theory, Earth has a rigid outer layer, known as the lithosphere, which is typically about 100 km (60 miles) thick and overlies a plastic (moldable, partially molten) layer called the asthenosphere. The lithosphere is broken up into seven very large continental- and ocean-sized plates, six or seven medium-sized regional plates, and several small ones. These plates move relative to each other, typically at rates of 5 to 10 cm (2 to 4 inches) per year, and interact along their boundaries, where they converge, diverge, or slip past one another. Such interactions are thought to be responsible for most of Earth’s seismic and volcanic activity, although earthquakes and volcanoes can occur in plate interiors. Plate motions cause mountains to rise where plates push together, or converge, and continents to fracture and oceans to form where plates pull apart, or diverge. The continents are embedded in the plates and drift passively with them, which over millions of years results in significant changes in Earth’s geography.
The theory of plate tectonics is based on a broad synthesis of geologic and geophysical data. It is now almost universally accepted, and its adoption represents a true scientific revolution, analogous in its consequences to quantum mechanics in physics or the discovery of the genetic code in biology. Incorporating the much older idea of continental drift, as well as the concept of seafloor spreading, the theory of plate tectonics has provided an overarching framework in which to describe the past geography of continents and oceans, the processes controlling creation and destruction of landforms, and the evolution of Earth’s crust, atmosphere, biosphere, hydrosphere, and climates. During the late 20th and early 21st centuries, it became apparent that plate-tectonic processes profoundly influence the composition of Earth’s atmosphere and oceans, serve as a prime cause of long-term climate change, and make significant contributions to the chemical and physical environment in which life evolves.
For details on the specific effects of plate tectonics, see the articles earthquake and volcano. A detailed treatment of the various land and submarine relief features associated with plate motion is provided in the articles tectonic landform and ocean.
In essence, plate-tectonic theory is elegantly simple. Earth’s surface layer, 50 to 100 km (30 to 60 miles) thick, is rigid and is composed of a set of large and small plates. Together, these plates constitute the lithosphere, from the Greek lithos, meaning “rock.” The lithosphere rests on and slides over an underlying partially molten (and thus weaker but generally denser) layer of plastic partially molten rock known as the asthenosphere, from the Greek asthenos, meaning “weak.” Plate movement is possible because the lithosphere-asthenosphere boundary is a zone of detachment. As the lithospheric plates move across Earth’s surface, driven by forces as yet not fully understood, they interact along their boundaries, diverging, converging, or slipping past each other. While the interiors of the plates are presumed to remain essentially undeformed, plate boundaries are the sites of many of the principal processes that shape the terrestrial surface, including earthquakes, volcanism, and orogeny (that is, formation of mountain ranges).
A cross section of Earth’s outer layers, from the crust through the lower mantle.
A cross section of Earth’s outer layers, from the crust through the lower mantle.
Encyclopædia Britannica, Inc.
تعلیم و تعلُّم کی اہمیت کو دینِ اسلام نے بہت اُجاگر فرمایا ہے، نسلِ انسانی کے … ٭اس بات کا انتظار نہ کرے کہ استاد صاحب سبق سُنانے کافرمائیں گے تو سناؤں گا … میں وہ اپنے اسباق کی اچھی تیاری کے ساتھ ساتھ غیرنصابی مطالعہ وغیرہ بھی … link text
Question 2: How can do make a discrete event simulation in excel? 15.
I. Introduction to Discrete-Event System Simulation. Chapter 1 Introduction to Simulation … Simulation models designed for training make learning possible without the … The second rule says that simulation should not be used if the problem can … 2. 9. 1 1. I. 15. 15. 4. Table 2.5 Chronological Ordering of Events. Event Type.
Separation of nucleic acids by agarose gel electrophoresis works by harnessing the … Agarose gels are cheap and can be used to examine RNA or DNA stability. … precipitate out of solution when stored at higher concentrations (10× solution, … There are three factors that affect migration rate through a gel: size of the DNA, …
Differentiate between uterine endometrium and chorion (05)
The endometrium is the inner epithelial layer, along with its mucous membrane, of the … Vascular spaces fuse and become interconnected, forming the placenta, … These two layers occur only in the endometrium lining the cavity of the uterus, … the ovarian cycle or the uterine cycle by observing microscopic differences at …
Alina belongs to Neurobiology and developmental neurobiology (sub specialization of neurosciences); because Alina conducted some experiment to know about the hypothalamus and its activities. After conducting some experiments, she comes to know that hypothalamus plays a significant role in eating behavior of rats.
Afifa wants to know influences of hormonal secretions on behavior. She studied about all the hormonal changes of the body so according to the scenario it comes on Neuroendocrinology which is also subfield of neurosciences. In this field; we study about the human’s internal system, their work and also their effects on human behavior.
This scenario belongs to medicine which cure the mental illness of the patient that is why this scenario will discuss on the Neuropharmacology, because pharmacology is the studies of medicines either medicines of physical illness or mental illness. It is obvious thing that every medicine has some side effects with their good effects. But people should take medicines for getting good result of some serious illness.
Natural selection affects all living organisms, in keeping a species strong and fit for existence under the conditions in which it is living. Natural selection pressures can work only in the presence of genetic variability Adaptations made in one generation; if beneficial would be carried on to the next generation there is constant process of adaptation. If species do not adapt they do not survive (dogs which do not learn to watch for cars on the road, die which means the end of their genes). Primates developed extensions to help in survival/hunting (young chimps use hollow sticks for ants), as they could not compete with the stronger hunters and predators.
Azaan could recall the complete story of the cartoon. Which lobe of the brain is involved in it? Name and justify.
Recall in memory refers to the mental process of retrieval of information from the past. … He would provide participants in his study with an excerpt from a story and then … This included new theories on how to view memory, often likening it to a … This means that recall only occurs if these two brain regions (rhinal cortex and … link text
As for civil society strengthening democracy, the distinctive feature of the movements of the 1970s is that they saw sites for social change beyond the state, for example in family and personal relationships, in culture, at work, with neighbours - wherever there were relationships between people, including internationally, and even spanning relations between humans and the physical environment. The feminist movement is perhaps the classic example, but the same methodology - ‘change starts at where you are’ - permeated most of the movements, including the peace movement of that period. People refused to reproduce consciously the relationships of injustice or oppression in which they were complicit, including, in the case of women, relations which caused them to suffer, but in which they acquiesced. The actions taken to break out of daily acquiescence, whether by organising collective childcare, or by marching off to surround a missile base, or by refusing to work in unsafe conditions, became an independent base from which they tried to change government or municipal policies: to get public funding for childcare, to force a withdrawal of missiles, or to win legislation to give workers the power to veto unsafe conditions. Civil society at this point had the power to transform the state. In many situations, it used this power to ensure that elected governments implemented their election promises. In these historical examples, civil society directly strengthened democracy in the sense of its core meaning: ‘government by the people’. They made the link between the people and their representatives more direct, more actively accountable.
In central and eastern Europe, too, the thinking and the activity of the 1980s networks of dissent went beyond classical understandings (Tocqueville, 1835/1988; Kaldor and Vejvoda, 2002) of the relation between civil society and democracy. In the classic Tocquevillean view, the very existence of civil society - understood basically as social associations and relationships of all kinds independent of the state - was a protection against abuses of state power. In the thinking and language of the 1980s, central and eastern European dissident networks composing ‘civil society’ moved from this defensive role to something more proactive. Increasingly, the term was used to refer to a diffuse agency for change with an emphasis on selforganisation, mutual support and autonomy, which, not necessarily intentionally, increasingly became a de facto challenge to authority. Under almost total state domination, as Solidarity founder Lech Walensa put it, ‘to laugh is to become political’. Jazz clubs in the beer cellars of Prague, informal gatherings in the baths of Budapest and ‘networks of sympathy’ across central Europe all nurtured political revolt. Such civil society initiatives formed, partly through the repressive reaction of the state, partly through their own persistence and moral integrity, the foundations of a struggle for democracy in eastern Europe. It was an experience which, like the social movements in the West, reinforced the idea of a natural spillover from democratic initiatives in civil society to the democratisation of political power.
Both these experiences of connection between civil society and democracy depended on conditions that were taken for granted at the time and even treated with contempt in the West, but which now have been all but devastated by unregulated market economics. In western Europe, the pressure civil society could apply to bring about democratisation of the state depended on already existing social democratic institutions at national and local levels, and a powerful mainstream party publicly committed to social justice and dependent in part on the support of civil society networks, including trade unions. These social democratic institutions provided connections and wiring - sometimes tangled and blocked - through which currents of democratic energy could flow, from civil society through to political power. In eastern Europe, the idea of civil society as a source of democratic agency depended on loose forms of solidarity, values of mutual support and a subculture of social relationships that rejected both the bureaucratic collectivism of official Communism and the commercial, uncaring individualism encouraged by corporate capitalism.
In western Europe, privatisation, deregulation and a generalised onslaught on state provision has weakened the leverage of civil society on political institutions. In contexts of thoroughgoing privatisation, the absence or weakness of a partner or means of dialogue within the state has led to a separation, locally, of civil society from political power. This has led to the marginalisation of civil society as a source of power, sometimes paralleled by its elevation as a source of legitimacy for an increasingly undemocratic state. In central and eastern Europe, the rampant character of the market has made it difficult for the velvet revolution networks to sustain themselves as lasting pressures for democracy. Autonomous civil society activity continues, but with little purchase on political power.
The democratic force of civil society: a local example
A useful case study to start with is one that shows civil society strengthening popular control and achieving greater political equality, and in so doing reinvigorating corrupt representative institutions. The increasingly well-known, almost emblematic, experience of the participatory budget in Pôrto Alegre, the site of the first three WSFs, though local in origin, has become influential internationally, spreading the principles of civil society as a means of deepening democracy.
While the movements for democracy in central and eastern Europe emphasised the democratic power of civil society through autonomy from the state, the Brazilian initiatives illustrate the democratic impact of civil society as a source of power, based on this autonomy, over the state. From the late 1980s and early 1990s, when the Brazilian Workers’ Party (PT) won electoral victories in significant cities like Pôrto Alegre, the capital of the southern region of Rio Grande Do Sul, Brazilian civic movements and NGOs working closely with the PT pioneered participatory budgeting (PB), a form of municipal government through which democratically organised civil society strengthened popular control over local state institutions. Through a process of direct popular participation in determining the priorities of the city council’s budget, and then in monitoring how these priorities were carried out, direct and delegated forms of democracy provided a means of democratic control over the state apparatus, and also corporate investors, which complemented the relatively weak control of elected representatives. An open process of negotiation replaced a more hidden decision-making process, which, though accountable to the mayor, had involved public officials exclusively.
The historical origins of PT are distinctive to Brazil, though international experiences of exile and continentwide influences, such as liberation theology, have been important. Formative influences on the PT lie in the popular movements: militant trade unions from the industrial hinterland of São Paolo; radical Catholic cells, rural and urban; the landless movement; committed intellectuals and students. The end product, the Partido Trabhalidores, has been uniquely influenced by and dependent on grassroots civil society organisations. In resisting the dictatorship, these organisations created their own kinds of participatory democracy at the same time as they campaigned for liberal democratic rights and the democratic rule of law. These two kinds of democracy have been fundamental to the PT ever since. They are glued together by, among other influences, the cultural egalitarianism of Paulo Freire.
Freire’s approach illustrates what has been distinctive about the PT. Known in the West primarily as a theorist of education, he was also a theorist of power, observing the way we imitate traditional patterns of power and reproduce them when we ourselves gain any power. The goal of his approach to education was to break these patterns and so obstruct the reproduction of established power relations. The PT’s participatory methods of government carry through to politics Freire’s emphasis on cultural as well as political and economic transformation.
This leads to an unusual modesty for a political party, which could account for the longevity and selfcorrecting mechanisms of the experiment. Celso Daniel, a founder of the PT and former mayor of Santo Andre, expressed this awareness of the limitations of political office. ‘We believed in taking with us into office the principles of democracy from the movements from which we came’, he said. ‘That meant sharing political power, the management of the city, with the community.’ ‘Finance is power’, declared Daniel. So the first test of sharing power was to open up the process of setting the budget (Wainwright, 2003: 31).
The invention in Pôrto Alegre of what has since become an elaborate, law-governed, transparent process of popular negotiation across neighbourhoods and between participatory and municipal representatives began with a practical problem. When the newly elected PT mayor in 1989 looked at Pôrto Alegre’s finances, he Found the city virtually bankrupt, with evidence of rampant corruption. Instead of presuming to sort the problem out within the town hall, the PT called a meeting of residents and community organisations in the city. Together, they worked out a system not only for direct popular involvement in setting priorities but also for democratic monitoring of spending. The consequences in terms of democracy were not consciously planned, but what began as a precarious experiment produced a new kind of public institution. In practice, if not yet in theory, elements of a new paradigm of relations between civil society and political democracy came into being. There is a tendency to make an icon of Pôrto Alegre whereas, like any experiment with democracy, it is a messy, uncertain process, now with 15 years’ hindsight to learn from its mistakes. Some achievements, however, can be summarised for their wider relevance.
First, over time, it led to the creation of an autonomous, transparent and generally accountable public sphere, which acted as a permanent watchdog over state institutions, supplementing the weaker but formally more legitimate role of elected politicians. This watchdog ensured the effective delivery of the mayoral mandate, in particular the reduction of inequalities of income and access to services (Wainwright, 2003: 66) (1). Second, it established transparency and accountability over municipal state departments that had become a law, and a little empire, unto themselves, moving into orbit beyond the effective control of elected politicians, who were often preoccupied with their careers. Finally, the combination of a participatory process honed by years of experiment and self-correction, and a representative system shaken into vigilance by this new citizens’ watchdog, increased the overall legitimacy of local democracy. This, in turn, increased the city’s bargaining power with international organisations such as multinational corporations, the World Bank and the Inter-American Development Bank.
The case of Pôrto Alegre - and of the other Brazilian cities that have followed it, including parts of São Paulo - does not prove the democratic impact of civil society. Possibly, this cannot ever be proved in a general way. It does, however, illustrate the strengthening of democracy through the sharing of important decisions, often the outcome of tough negotiation between elected politicians and democratic civil society. The mayor, whose power derives from votes, has the final say, but without the effective participation of civil society, the mayor will not be able to carry through the policies for which he or she was elected. Hence the quality of life in the city will suffer and the mayor might well lose his or her position. Mutual dependence, therefore, underpins the process of negotiation, which needs two preconditions: first, that civil society mobilises sources of popular power (including knowledge) unavailable to the state and lets them speak, and second, that the political representatives of the state listen and act.
The WSF and the democratic power of civil society
From the point of view of civil society’s relationship to democracy, the WSF and the international connecting and campaigning that it has helped to stimulate raise four distinct issues. First, the WSF has strengthened the transformative power of civil society. Second, this power is being asserted in order to call governments to account for their acquiescence in the international treaties and deals of free market economics, and their support for US military and political ambitions in the Middle East. Third, these developments are producing a radical, open-ended shift in the relations between civil society and political parties. And fourth, within the WSF and the social forums, forms of organisation are being invented to fulfil the forum’s aim of facilitating a plural horizontal network of active campaigns. Many questions arise about the sustainability of this process: questions about the obstacles and legacies of more traditional, vertical traditions of the left that these innovations come up against; and questions about whether the WSF process has the depth and resilience to overcome these conflicts and tensions of emphasis and understanding (Corrêa Leite, 2004)
On the first issue of strengthening the transformative power of civil society, the social forum process has strengthened the power of civil society to bring about democratic change, in several ways. First, the forum has progressed from a predominantly Latin American affair, appealing mainly to the organised trade unions, landless movements and progressive intellectuals, to becoming a genuinely open and near-global public space for resistance and alternatives to the neo-liberal world order. The result is that it has given otherwise isolated groups - young people, unemployed, precarious workers, Dalits (the ‘untouchables’ in the Indian caste system), abandoned rural and urban communities - a boost in collective selfconfidence and experience of being part of a wide and potentially powerful movement. Just as the encounter of Chinese women with Western feminism gave independent Chinese women’s organisations access to a new language and stream of thinking about self-determination, autonomy and self-organised agency, so encounters within the WSF have enabled traditionally marginalised groups that lack obvious strategic power to move from a consciousness of injustice and oppression to an awareness of feasible connections and directions through which they can achieve change.
While extending the reach of radical civil society, the meetings of the WSF and the process of working together to prepare for them have also strengthened the cohesiveness and strategic thinking of international campaigns and action-oriented research. Although after four annual forums there is a wariness of being or becoming a ‘talk shop’, there is no doubt the forums have stimulated the growth and spread of a huge variety of campaigning, cultural, solidarity and other networks - including networks of groups working on practical alternatives in, for example, production and agriculture, or public administration. The extraordinary show of organised and politically disenfranchised public opinion seen in the anti-war demonstrations of 15 February 2003 is one sign of the increase in the international cohesiveness and density of progressive civil society. The date was suggested at the European Social Forum in Florence, echoed through innumerable networks, reinforced and spread globally at the third WSF in Pôrto Alegre in January 2003, and on 15 February became a symbol of ‘the second superpower’, which the first power, the US government, ignores at its peril.
Behind the scenes of these dramatic mobilisations, the No US Bases Campaign provides a good example of the WSF helping to initiate all kinds of sustained cross-border coordinated action. These bases are the points at which the US government becomes physically present across the world, so providing a focal point for calling it and its allies to account. The campaign draws strength from a long tradition of international peace movement collaboration, as well as established local campaigns of base-affected communities. This mixture of local campaigning experience and international networking is crucial to the campaign’s success. In particular, the work of creating a global network has been facilitated (not led) by radical NGOs with extensive experience in this area. The WSF was treated as an important part of a wider process rather than an end in itself. The No US Bases Campaign was the product of two strategic international peace conferences held in May 2003: the Hemispheric Encounter against Militarisation in Chiapas, Mexico, and the Jakarta Peace Consensus in Indonesia. An open coordinating group and email list were established after the Jakarta Conference, and related meetings were held in Cancún and Paris (Reyes and Bouteldja, 2004). This offers a valuable lesson in how the WSF can be used in conjunction with other campaigns and international encounters of the global justice and anti-war movement. Although a thorough mapping of the actions that flow from a meeting of the WSF or another social forum has yet to emerge, this kind of development is central to the potential of the WSF as a new organisational form through which to realise the transformative potential of civil society.