O-zone Depletion Research Paper Example | Topics and Well Written Essays - 1250 words

O-zone Depletion - Research Paper Example In this context the problem of ozone depletion can be explored. The ozone layer can be thought of as a giant sunshade that covers around 9 to 19 miles above Earth surface protecting the plants and animals of the earth from the harmful ultraviolet B rays (U.V B) radiated by the Sun. Stratosphere contains Ozone (O3) in the form of a layer surrounding it. The stratospheric span is around 30 miles above the surface of the earth. The harmful U.V rays are absorbed by the ozone layer that prevents it from entering the earth surface. However, if and when ozone is found on the earth surface, it can act as a very harmful pollutant. Moreover, ozone is responsible for the greenhouse effect. (Ozone Depletion  Losing Earth’s Protective Layer, n.d.) This paper attempts at discussing the underlying causes and effects of Ozone depletion and tries to make a comparative study of the various environmental policies taken to combat the problems related to ozone layer depletion and its possible so lutions.  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   Causes and Effects of Ozone Depletion: In recent years, ozone layer depletion has been a subject of concern for the scientists. Ozone layer depletion was first discovered in the 1980s with Antarctica being the earliest of the victims. Ozone depletion in stratosphere is being considered the foremost problem regarding environmental degradation, which threatens the very existence of life on the planet. A large stratospheric hole had been discovered just above Antarctica which is increasing everyday letting the harmful U.V B rays to enter the earth surface which is resulting in elevating the risk of skin cancer, immunological and genetic damages and cataracts in the eyes. It is also causing skin burns in whales and massive damage to essential food crops such as wheat, rice etc., and increase in production of harmful vitamin D. Moreover, impact of anthropocentric activities in the troposphere and stratosphere ha s been on the rise, which also results in depletion of ozone layer. This has allowed Ozone Depleting Substances (ODS) like halocarbon refrigerants (CFCs, halons, freons) emanated from man made cars and factories to reach the stratosphere and degrade it further. The halocarbons are chemically photo dissociated and enabled to release halogens, which through a series of chain reactions destabilizes ozone and converts it to oxygen (Melott & Thomas, 2011). In the past one and a half decade some measures have been undertaken in terms of international protocols and policies in order to combat this environmental threat.  To understand and improve upon these measures an evaluation of these policies and protocols might help. International protocols and their evaluation    Kyoto Protocol:   The Kyoto Protocol treaty comprises of a set of rules by United Nations Framework Convention on Climate Change (UNFCCC) negotiated at Kyoto, Japan in 19th of December 1997 agreed five years back at th e Rio Earth Summit in 1992 and have been operational since 16th of February, 2005. It is a legally binding protocol according to which the industrialized nations would have to make a cut in their collective emissions of Chlorofluorocarbon (CFC) gases by 5.2%  and were expected to reduce emissions by 29% within 2010.The aim was to reduce overall emissions of six main harmful greenhouse gases including methane, CFC and nitrous oxide, calculated over a 5- year period average of

Discuss the role of the motor cortex in movement. 1500 Words Essay

Discuss the role of the motor cortex in movement. 1500 Words - Essay Example The motor cortex plans voluntary actions – it helps in initiating, planning, controlling and maintaining voluntary movement of skeletal muscles, coordinates sequences of movements and relay commands to the appropriate sets of lower motor neurons to execute the desired actions. Diseases or traumas on this part of the brain have adverse effects on the patient. Presently, such diseases include Apraxia, which causes an inability to initiate purposeful learned movement in response to external commands despite the ability and desire to perform the movement, and Parkinson’s and Huntington’s disease – characterized by loss of the ability to initiate movement or stop it once initiated plus the occurrence of uncontrollable movement. Modern man, Homo sapiens, has an average cranial capacity of 1350cc far more than all his other earlier ancestors. This increased cranial capacity is credited for his higher intellectual ability over other animals and primates. The brain serves many functions in the body, from thought to emotions, waking and sleeping, respiration, memory, controlling actions just to mention but a few and can thus be considered as the central control for the whole body. Like all other living things, man also moves around in search for food, flight from danger or for pleasure. Movement is a function of muscular flexion and extension all which are under the control of the brain – except for reflexive movements, which are controlled by the spinal cord and mainly help maintain posture and balance without involving the conscious mind. The brain is divided into six main parts; the cerebral hemispheres, hypothalamus, thalamus, cerebellum and the brain stem – mid brain, pons and medulla oblongata, each of which has its different functions (Marieb, 2000). The cerebellum contains a region known as the motor cortex in the precentral gyrus that helps in initiating, planning and controlling voluntary movement of skeletal muscles. The motor cortex is further