Critical Review of the pathogenicity of measles, the symptoms associated with the infection and how to prevent the potentially fatal disease. The WritePass Journal

Critical Review of the pathogenicity of measles, the symptoms associated with the infection and how to prevent the potentially fatal disease. Introduction Critical Review of the pathogenicity of measles, the symptoms associated with the infection and how to prevent the potentially fatal disease. IntroductionInfection and Spread  SymptomsVaccinesConclusionRelated Introduction Measles is a contagious human disease that mainly affects children. The measles virus (MV) that causes this systemic infection is a single stranded ribonucleic acid virus belonging to the genus Morbillivirus in the Paramyxovirus family.(2,3) As transmission is via air droplets, initiation of the infection occurs in the respiratory tract, and spreads to other organs. MV affects the immune system leading to a prolonged state of immune suppression which can result in several complications involving the respiratory tract and the brain e.g. encephalitis.   Immunisation using a live attenuated vaccine is the main preventative of the infection.   In 2000, the cases of infection of measles in Europe was rare due to vaccination, however in 2008 there was a total of 7,822 (5) with Switzerland having the highest incidence rate in Europe. (6) Measles are increasing in Ireland, with 320 cases reported within 8 months in 2009. (7) The objective of this assignment it to review the pathogenicity of measles, the symptoms associated with the infection and how to prevent this infectious and potentially fatal disease. Infection and Spread Infection is initiated in the respiratory tract. (8) The virus can then spread to the local secondary lymphoid tissues via dendritic cells of the lungs or the alveolar macrophages. (8) From here it can travel to the peripheral blood and spread via epithelial and endothelial cells to multiple organs. Research has suggested that in the later stages of the infection, the virus infects the epithelial cells of the respiratory tract facilitating in the spread of the virus. (9)   But how does the virus invade its host? MV is a non – segmented negative sense strand enveloped RNA virus that encodes 8 proteins: 6 structural proteins and 2 non-structural proteins. (8) The first 3 structural proteins are combined within the RNA. The (N) nucleoprotein protects the genomic RNA by forming the ribonucleocapsid. The phosphoprotein (P) and large polymerase protein (L) are involved in viral replication. (4, 8) The non- structural proteins C and V are responsible for the regulation of viral infection by interacting with cellular proteins. (11) The F and H glycoproteins found on the surface of the virus envelope, are responsible for the initiation of infection to susceptible host cells. These transmembrane proteins allow the virus to fuse with the host cell, penetration of the virus into the host cell and haemolysis. (4) The F protein facilitates the spread of the virus from one cell to the other by inducing cell fusion. (4) Transcription occurs within the cell to create more negative sense RNA for assembly of new budding viruses (see figure 1). (10) The matrix M protein is a non-glycosylated protein found in the inner lipid bilayer of the envelope. Its function is to connect the ribonucleoprotein complex to the envelope glycoproteins during viral assembly. (8) The H protein of the virus surface is responsible for receptor binding. CD46 was the first identified receptor for MV and is present on all nucleated cells. (8)   It was later discovered that the signalling lymphocyte activation molecule (SLAM) also known as CD150 has also been identified as receptor for MV. (3, 8) In fact the receptor binding of CD46 seems to be limited to attenuated vaccine strains rather than the wild type which seems to have better affinity for the CD 150 receptor. CD150 is expressed on many immune cells including lymphocytes, dendritic cells and macrophages and is a member of the CD2 subset of the Ig superfamily. (3, 8) The structure of H protein of MV is well documented consisting of a globular head group composed of 6 anti-parallel B sheets. These are stabilised by two intra- monomeric disulphide bonds and partially covered with N-linked carbohydrates. (12) The binding regions for CD 46 and CD 150 (SLAM) are found adjacent to one another. (3) It has been widely documented that CD150 is the initial receptor targeted by the H protein of the virus but little is known on the receptors involved in the infection of epithelial cells as these cells do not express CD150. (3)   Tahara et al have resulted that â€Å"MV has the ability to infect both polarised epithelial and immune cells using distinctive receptor – binding sites on the H protein†. (3) His study used a CD150 negative human lung adenocarcinoma cell line (NCI-H358) to infect with the MV. The presence of the H protein was evident using monoclonal antibodies and suggesting that the H protein must have been using a different receptor binding site to infect the cells. (3) The pathogenesis of MV, initiates an immune response. It triggers a cell-mediated immune response which involves the activation of TH1 and release of interferon ÃŽ ± and interleukin 2 (IL-2). (13) In the later part of the infection an antibody- mediated response provides long term protection against future infections. TH2 lymphocytes are produced as well as IL-4 which favours the induction of a humoral response which is important for long life protection against re-infection. (8, 13) However MV has the ability to dominate the immune system and use it to its advantage. The suppression of the immune system results in secondary bacterial and viral infection which attributes to the number of fatalities associated with Measles infection. Moss et al suggested that there are many mechanisms that develop to immune suppression following a MV infection. (14) These include: Lymphocyte Apoptosis Impaired Lymphoproliferation Immunomodulatory Cytokines (Increased IL-10 and IL-4) IL-12 down regulation Impaired Antigen Presentation of Dendritic cells One of the clinical manifestations of MV is lymphopenia. This may be due to the reduction of CD4+ and CD8+ T lymphocytes. Increased surface expression of Fas (CD95) during acute measles suggests that unaffected T lymphocytes undergo apoptosis. (14) Abnormalities in the lymphocyte function are found during and after MV infection. The virus inhibits IL-2 dependent T lymphocyte survival and proliferation. This is in response to an impaired protein kinase B activation caused by the H and F proteins of the virus. (14) In the acute phase of infection a T helper Type 1 (TH1) response is induced which shifts to T helper type 2 (TH2) in the later stage of infection which accounts for viral clearance and development of antibodies respectively. (8) The increased production of cytokines IL-10 and IL-4 in the TH2 response may be another mechanism for viral induced immunosuppression. IL-10 is an immunosuppressive cytokine which down-regulates the synthesis of cytokines and suppresses T cell proliferation and macrophage activation. (15) This prevents macrophage activation and TH 1 response to new infections. (8) As previously mentioned CD 46 is found on many immune cells including monocytes. As a result IL-12 produced by monocytes is downregulated. (16) IL-12 is essential for TH1 immune response. (15) The reduction in production of IL-12 favours TH2 and suppresses TH1 immunity. (17) Dendritic cells play a critical role in the presentation of antigen to naà ¯ve T lymphocytes. MV infection promotes maturation of dendritic cells but also alters its function (18) and mediates Fas induced apoptosis. It is now established that the non-structural protein C and V produced by the P gene plays a role in immunosuppression by interfering with interferon ÃŽ ±/ÃŽ ² signalling pathways. (8)   These proteins of the MV inhibits phosphorylation of STAT 1 and STAT 2 which are transcription factors involved in the Interferon pathway. (14)   Symptoms Clinical symptoms associated with measles include a fever and rash but a cough, coryza or conjunctivitis can also be seen. (9) It is after 10-14 days of infection that this characteristic rash is present and seems to be due to the individuals’ immune response to the virus. (8) The rash usually begins on the face and travels down to the extremities and can last for about 5 days before disappearing (4) Two thirds of patients show a white-marked enanthema on the buccal mucosa known as Koplik’s spot. (2) Koplik spots were first identified by Koplik in 1896 and are the pathognomonic of measles. (4, 5) Generally the resolution of the rash and fever begins after 7 to 10 days however the cough may persist for longer. (4) In many cases complication can occur resulting in infections of the respiratory tract and brain. Pneumonia accompanying measles may be due to the MV or a secondary bacterial infection. (4) 60% of infants infected with measles, can die from pneumonia while older children (10 -14 years) death is associated with acute encephalitis. (4) It seems that viral infection of the CNS is a common feature of measles but only a proportion of patients will present with clinical symptoms. Mild forms of measles have been observed due to passive immunity to the virus. Infants who have passively acquired antibodies to MV from the mother will present with some of the symptoms but depends on the degree of passive immunity that is achieved. (4) A study in China determined that mothers produced low levels of antibodies due to vaccination rather than natural infection. The outcome is reduced protection to the infant which can result in measles infection before the age of receiving a vaccine. (19) Atypical measles is associated with patients who received a vaccine using a killed MV rather than live attenuated vaccine and subsequently was exposed to the wild-type measles virus. Patients present with a low or undetectable titre which drastically rises after a few days. (4) As the symptoms may vary to classic measles, it can be misdiagnosed. Atypical measles is more severe than classic measles. Research has shown that this may be due to the fact that the killed vaccine lacks the antigen to stimulate immune response by preventing the virus entering the cells. (4) It has been shown that the killed vaccine does not produces antibodies to the F proteins which facilitate cell entry and spread of the virus. Immunocompromised patients present with severe measles due to their deficient cellular immunity. Secondary infections are often seen including pneumonia and encephalitis resembling SSPE.   Malnourished children especially in the developing world can suffer from severe measles. This may be due to intense exposure due to crowding or the inability to produce a cell-mediated response due to malnutrition. (4) Measles is regarded as an infection of childhood however adults do get infected and usually develop a severe form which can have complications. During pregnancy, an infected mother is not known to cause co-genital abnormalities to the foetus but may cause abortion or preterm delivery. (4) Vaccines The use of vaccines is the main preventative of Measles. The development of the first measles vaccine was in the 1960s. (20) Immunisation began with a inactivated (killed) vaccine, but resulted in short term protection and undeveloped immune system. (20) Immunisation with a live-attenuated vaccine can be administered as a monovaccine or in combination with mumps and rubella (MMR) or mumps, rubella and varicella virus (MMRV). (2) It is derived from a wild type of the virus known as Edmonston and processed through chicken cells. (8) In 1985, the measles virus was first introduced in Ireland, with the combination vaccine (MMR) emerging in 1988. (7) When the vaccine was first introduced in Ireland 9,903 cases of measles were reported. This dropped to 201 cases in 1987. (7) A two dose vaccine is essential for long lasting protection to the virus. (21) There are occasions when passive immunisation is required using immunoglobulin which include immunocompromised patients such as HIV positive patients. (4) Successful vaccination against infectious diseases depends on the vaccines ability to induce a protective response. Successful vaccination is dependent on the individuals’ human leukocyte antigen (HLA) haplotype which regulates the immune response. (22) There are two types of HLA proteins. The first, Class I consists of A,B and C alleles.   These bind to CD8+ T lymphocytes. (23) Class II DR,DQ and DP alleles attach and present peptides to CD4+ T lymphocytes. (23) The measles vaccine results in an iatrogenic attenuated measles infection. As mentioned previously, the C46 molecule serves as the receptor for the H protein of MV where it is broken down and presented to the immune system by the HLA system. (22) Studies have shown certain HLA alleles may impact differently on the responsiveness to the measles virus.   (22) For successful herd immunity to measles, most of the population needs to be immunised. However fears of the association of the MMR vaccine and autism have stopped parents from vaccinating their children. There is no scientific evidence to suggest any link with autism. (24) Research has suggested that Vitamin A supplementation may help prevent Measles infection in infants prior to vaccination. (25) Subacute Sclerosing Panencephalitis. (SSPE) One of the persistent secondary infections of MV is subacute sclerosis panencephalitis (SSPE) which causes demyelination of the central nervous system (CNS). (13) SSPE cannot occur without the presence of a direct measles and is found to be more prevalent in males than in females. (26) Research has shown that the earlier a patient is infected with MV the greater the risk of complications such as SSPE can occur. This is due to an immature immune system. (13) Conclusion The MV invades the neurons using the CD46 receptor and using its F protein. (13) There have been studies to suggest that another receptor CD9 aids entry into the cell. Once inside the cell the virus changes the machinery of the cells to avoid an immune response. It undergoes mutations of its own proteins to go unrecognised and reproduces within the neurons. (13) The virus can live as a â€Å"parasite† within the neurons for years. Finally it will damage the cell to an extent that apoptosis will occur and the immune system is triggered. Onset of SSPE is usually 6 years after infection and clinical symptoms present as intellectual deterioration and behaviour abnormalities.   Final stages include seizures, focal paralysis and death with akinetic mutism. (13) There is no cure for this fatal disease only a preventative. Other fears related to the vaccine were that it may cause SSPE however there is no evidence to back this case.

Communication - Monroe's Motivated Sequence Assignment

Communication - Monroe's Motivated Sequence - Assignment Example what you’re doing in your communities as what we’re doing here in Washington; and it’s gonna take all of us working together.† These lines create the need in every listener living in America. It creates the realization that people should do their part too because any good outcome will also be for them. Satisfaction - The First Lady introduces the project â€Å"United We Serve† and presents how everybody can make the changes needed. She states: â€Å"With the knowledge that ordinary people can achieve extraordinary things when given the proper tools, this initiative aims to both expand the impact of existing organizations and encourage people like you and me to develop our own do-it-yourself service projects.† She presents a tangible, possible solution to the current problem. Visualization - The First Lady painted a verbal picture of how fulfilling it is to help other people achieve their goals. â€Å"The fulfillment of putting your faith into action and feeling that you’re part of something bigger than yourself, and doing your part for the greater good.† According to Price, this is an effective way to â€Å"appeal to [the listeners’] emotions and desires.† Action - As Price mentioned, â€Å"Remember, people don’t like to get outside of their comfort zones and spend their own time solving the problem you’ve presented, so be sure to make the action steps easy on them.† Thus, the First Lady’s offer to simply â€Å"Log on to serve.gov and let’s work together to build a new foundation for America† makes it easy for the people to act. It basically makes one feel that the solution is right at the tip of their fingers, and all they need to do is to click. Attention – Beiber’s opening statement of facts about being a teenager grabs the target market’s attention. â€Å"There are some things that just come with being a teenager†¦And then there’s zits...I can’t stop that.† Immediately, the target market will want to hear more of what is being

TECHNOLOGICAL CONTROVERSY Essay Example | Topics and Well Written Essays - 2000 words

TECHNOLOGICAL CONTROVERSY - Essay Example As people use cell phone regularly and as it causes radiation it can cause cancer. The cell phone causing cancer is a controversial issue because some do not accept that this statement true. The scientific world has not gathered enough evidence to prove that cell phone can cause cancer. The assumption is based on the fact that the cell phone causes radiation. And radiation is a main reason for cancer. A continuous exposure to radiation is a fact that can convince the connection of cancer with cell phone use (NCI) .In theory, children have the potential to be at greater risk than adults for developing brain cancer from cell phones. Their nervous systems are still developing and therefore more vulnerable to factors that may cause cancer. So an examination of cell phone use and its effect on human body need to be studied. Scientists have been alerting people about the adverse effect of cell phone on humans. The fact is that the cell phone emits 1000 times higher than the base stations, and it has greater likelihood of causing problems to brain and upper part of human body. The epidemiological evidence suggests that there is an association between radio frequency emitted by wireless phones and head cancer. The radio frequency is classified by International Agency for Research on cancer as possibly carcinogens to humans. According to (Burrell 23-34 ) â€Å"A Swedish study on the use of wireless phones, including cell phones and cordless phones, has uncovered a link between electromagnetic radiation exposures and the risk of malignant and non-malignant brain tumors†. The studies reveal that the people who used cell phones for more than a year is at 70% risk of cancer and those who used cell phone for more than 1640 or more has 180% risk. The risk of cancer is greater in the part of the brain where cell phone was exposed. Many scientists have claimed that

Physiology Of Sleep

Physiology Of Sleep Physiology Of Sleep Introduction Sleep is a state of reversible unconsciousness in which the brain is low responsive to external stimuli. We are functionally blind during sleep with no response to visual stimuli and a decreased threshold of response to auditory stimuli. Babies have been exposed to sound of up to 100 dB, which is above the legal limit for ear protection for employees, without waking up. In adults, the action is selective demonstrating continuing cortical function. For example, a sleeping mother is woken by her crying baby but not by other louder noises. Definition of sleep and sleeping Phases with specific EEG patterns and physiological changes. Natural sleep is separated into two distinctive states: non rapid eye movement (N.R.E.M) and rapid eye movement (REM) sleep. NREM sleep is then further seperated into 4 stages where stage 1 is the lightest and stage 4 the deepest level of sleep. REM sleep is divided into phasic and tonic phases. The two distinctive states follow a regular pattern called a sleep cycle which, in an adult, lasts about 1 and half hours and comprises a period of N.R.E.M sleep followed by REM sleep. The cycles may be separated by a period of wakefulness and are repeated 3–6 times each night and are typically displayed as an hypnogram (Fig. 1). The majority of deep (stage 4) NREM sleep occurs in the first and second cycles. As the night progresses, the proportion of REM sleep in a cycle increases and the NREM element is of lighter stage 2 sleep. Age has a major effect on the duration of sleep and the ratio of NREM/REM sleep. Neonates sleep 16–18 h. It is widely distributed throughout the day with REM sleep accounting for 50% of total sleep time (TST). This may be even greater in premature babies. By the age of 24 months, children should sleep 10 h per day, mainly at night with one or two naps during the daytime and REM sleep has declined to 20–25% of TST. Adults normally sleep 6–8 h per day with 15–20% REM sleep. With increasing age, TST changes little although sleep is more fragmented with more frequent and longer awakenings (decreased sleep efficiency) with less REM sleep and more light NREM sleep. Night-time sleep may be decreased if naps are taken during the day. Functions of sleep The functions of sleep are still poorly understood. However, the observation that sleep (or, at  least, an activity–inactivity cycle) is present in all species and has been preserved throughout evolution and that sleep deprivation leads to a drastic deterioration in cognitive  function and eventually to mental and physical morbidity proves its importance. It has been suggested that sleep might conserve energy by reducing core temperature slightly and lowering metabolic rate by 10% compared with quiet wakefulness. Sleep would prevent perpetual activity as a response to environmental stimuli leading to excessive energy consumption. However, sleep is a state of starvation and there is no evidence that sleep is important for tissue repair. Sleep has been implicated as an important factor in storage of long-term memory. Facts learned during the day are usually better remembered the next morning whereas facts learned shortly before going to sleep are often poorly recalled. Electrophysiological features of sleep The stages of sleep are characterised by typical patterns of electroencephalogram (EEG), electro-myogram (EMG) and electro oculogram (EOG) activity Wakefulness with open eyes is characterised by an EEG with dominant low amplitude, high frequency beta activity of  16–25 Hz. Muscle tone is normally high with high to moderate EMG activity. Stage 1 Sleep is usually initiated by a transition from wakefulness to a state of drowsiness with closed eyes and a shift from EEG beta activity to alpha activity of 8–12 Hz passing to Stage 1  NREM sleep with a mixed frequency EEG-pattern with low amplitude theta waves of 3–7 Hz accompanied by slow rolling eye movements. Involuntary muscle clonus occurs frequently,  resulting in jerky movement of the whole body (hypnic jerks) and EMG activity is moderate-to-low. This stage lasts typically only 5–10 min, during which time minor auditory stimuli will cause arousal. Stage 2 Stage 2 is characterised by short bursts of high frequency activity (12–15 Hz – sleep spindles) and K-complexes (large amplitude biphasic waves). Bodily movements continue and  the EMG activity is low-to-moderate. This stage is generally short (10–20 min) in the first 1–2 cycles but predominates in later cycles. It is the most abundant sleep stage in adults  accounting for up to 50% of TST. Stages 3 and 4 Deep NREM sleep stages 3 and 4, sometimes combined as slow wave sleep (SWS) are characterized by high amplitude low frequency delta waves (> 75 µV and 0.5–2 Hz) with stage  3 having between 20–50% and stage 4 more than 50% delta activity. EMG activity is low and eye movements are rare. Arousal through auditory stimuli from this stage of sleep is  difficult and, if awakened, the individual is often disorientated and slow to react. Return to sleep is easy and short arousals (< 30 sec) are rarely remembered. REM sleep NREM sleep is followed by REM sleep, the proportion increasing with each cycle. REM sleep is characterised by a fast mixed frequency low voltage EEG with saw-tooth waves and  rapid eye movements on the EOG. During the tonic phases of REM sleep, there is marked reduction of muscle tone and EMGactivity in skeletal muscles. The tonic phases of REM sleep are interrupted by short episodes of phasic REM sleep with increased EMG activity and limb twitches. The atonia of REM sleep affects all skeletal muscles, except the diaphragm and the upper airway muscles, and is associated with hyperpolarisation of the ÃŽ ±-motor neurones. The purpose of this may be to prevent the acting out of dreams. About 10% of the population have experienced sleep paralysis (i.e. wakening from sleep and finding that the atonia has  persisted into wakefulness). It can be frightening but is entirely harmless. Natural wakening usually occurs from REM sleep. Subjects woken from REM sleep are much more likely to rec all dream content than those awakened from NREM sleep. NREM dreams are generally vague and formless in contrast to REM dreams. Physiological changes during sleep Respiratory system During NREM sleep, there is a decrease in respiratory drive and a reduction in the muscle tone of the upper airway leading to a 25% decrease in minute volume and alveolar ventilation and a doubling of airway resistance accompanied by a small (0.5 kPa) increase in  PaCO2 and decrease in PaO2. Hypercarbic and hypoxic ventilator drives are reduced compared with wakefulness. The breathing pattern is regular except at the transition from wakefulness into sleep when brief central apnoeas are common. During REM sleep there is a further decrease in hypercarbic and, particularly, hypoxic ventilatory drives. The breathing pattern is irregular especially during phasic REM sleep. The loss of skeletal muscle tone in REM sleep affects the intercostal and other muscles which stabilise the chest wall during inspiration. In infants, this may be seen as paradoxical movement of the rib cage and abdomen. In adults, there may be maldistribution of ventilation and impaired ventilation–perfusion matching with consequent arterial hypoxaemia. In normal subjects, this is unimportant but it may be very important in patients with chronic lung disease or abnormalities of the thoracic (e.g. kyphoscoliosis). The great majority of patients with impaired respiratory function will be at their worst during REM sleep. Cardiovascular system Blood pressure decreases during NREM and tonic REM sleep but may increase above waking values during phasic REM sleep. Cardiac output is generally decreased during all sleep  phases. Systemic vascular resistance (SVR) and the heart rate are both reduced during NREM and tonic REM sleep and increased during phasic REM sleep. Central nervous system Cerebral blood flow (CBF) increases by 50–100% above the level of resting wakefulness during tonic REM sleep and is even greater during phasic REM sleep. Cerebral metabolic rate, oxygen consumption and neuronal discharge rate are reduced during NREM sleep but increased above resting values during REM sleep. The autonomic nervous system shows a general decrease in sympathetic tone and an increase in parasympathetic tone,  except in phasic REM sleep. Renal system The glomerular filtration speed and filtration fraction are reduced and ADH secretion is increased resulting in a less volume concentrated urine. Endocrine system The secretion of several hormones is directly linked to the sleep/wake cycle. Melatonin is released from the pineal gland under the control of the supra-chiasmatic nuclei (SCN) in a 4–5h pulse, usually beginning at the onset of darkness (~9 pm). The pulse is inhibited or delayed by exposure to bright light in the evening. It is best regarded as being permissive of sleep (‘opening the gate to sleep’) rather than as an hypnotic, as it is possible to maintain wakefulness during this period. Growth hormone is mostly secreted during the first episode of SWS, particularly  during puberty. Prolactin concentrations also increase shortly after sleep onset and decrease with wakefulness. Sleep phase delay delays secretion of both of these hormones. The secretion of cortisol decreases with the onset of sleep and reaches a trough in the early hours of the morning and a peak just after waking. Temperature control In contrast to anaesthesia, thermoregulation is maintained during sleep. However, the shivering threshold is decreased and body core temperature decreases by about 0.5 °C in humans and 2 °C  in hibernating mammals. Body temperature is linked to the circadian rhythm and reaches its nadir at about 3 am. Thermoregulation is quite good in human infants compared with  other species. Control of sleep Sleep follows a circadian (~1 day) cycle, the periodicity of which is regulated by an independent genetically determined ‘intrinsic clock’ which is entrained to a 24 h cycle by external cues (Zeitgebers) such as light, darkness, clock time, working patterns and meal times. When a human being is deprived of all external time clues and is exposed to constant levels of illumination (‘free running’), the wake/sleep cycle typically lengthens to about 24.5 h. Subjects who are born blind without any appreciation of light generally free run while those blinded in later lifeor who retain some perception of light remain entrained. All living organisms, including plants and fungi, have been found to have clock genes and to show an inactivity/activity cycle. In mammals, control of the intrinsic clock is located in the SCN on either side of the third ventricle, just above the optical chiasm. In animal experiments, its destruction leads to a change from the normal sleep cycle into several shorter sleep/activity periods during the day. As noted above, melatonin secretion is  prompted by the SCN just before the usual time of sleep onset. A mismatch of this pattern with sleeping time, as occurs in shift workers and after trans-meridian flights, leads to sleep disturbance (‘jet lag’) as the subject is trying to sleep during their circadian day. Light therapy can be helpful in re-setting the circadian clock and the interested reader is referred to the bibliography. The propensity to fall asleep varies throughout the day and depends upon both circadian factors (process C) and time since the last sleep period (process S). The longer the time since the  last sleep period, the greater will be process S. However, its propensity will be modulated by process C. The circadian pressure to sleep is greatest at ~2 am with a secondary peak at ~2 pm. It is least at ~6 am and ~6 pm. If a subject elects to stay awake throughout the night, they will feel most sleepy in the small hours of the morning but will get a ‘second wind’ as morning approaches and the circadian pressure to sleep declines. If wakefulness is maintained, a second period of sleepiness and relative alertness will follow in early afternoon and early evening, respectively. Some of the 8-h sleep debt will be recovered that night but process C will ensure that awakening will occur at or shortly after the normal waking time. Sleep is normally an actively initiated and not a passive process. Unless a subject is sleep deprived, successful initiation of sleep depends both upon the phase of the circadian clock and  external factors (recumbent position, darkness, reducing sensory input). Over the years, considerable effort has been focused on a search for: (i) a ‘sleep centre’, a nucleus or region in the brain where stimulation or ablation would lead to sleep; and (ii) a hormone or transmitter which would reliably induce sleep. Neither have been found because the mechanisms resulting in sleep are complex and diffuse. During wakefulness, the CNS is dominated by activity of the ascending reticular activating system (RAS) in the brain stem. This formation receives sensory input from all peripheral sensors and projects to the thalamus and the cortex. Its main neurotransmitters are acetylcholine, noradrenaline, dopamine and histamine which explains the sedative effect of antagonists to these  substances. A decrease in its activity permits sleep to be initiated by suppressing incoming external stimuli. The induction of SWS is associated with the secretion of ÃŽ ³-aminobutyric acid (GABA) from basal forebrain neurones. Therefore, it is not surprising that benzodiazepines and barbiturates, which act through stimulation of GABA receptors in the CNS, induce sleep or anaesthesia. Cholinergic mechanisms initiate REM sleep through stimulation of pontine neurones in the  lateral portion of the pontine tegmentum and the nucleus reticularis pontis oralis. In animal experiments, injection of carbachol (acetylcholine agonist) induces instantaneous REM sleep. Recently, orexins (hypocretin) have been isolated in the hypothalamus and appear to be important in the control of REM sleep and appetite. CSF concentrations of orexins have been found to be very low in patients with narcolepsy. Influence of surgery and anaesthesia on sleep Anaesthesia and surgery can have a profound effect upon sleep. On the first night after surgery, sleep architecture is severely disrupted with little or no SWS and REM sleep. The  light Stage 2 sleep is fragmented with frequent awakenings. The degree of disruption appears to be related to the severity of the surgical insult. The mechanism is unclear but it is probably due to a combination of the surgical stress and the effects of opioid analgesics. Recovery of lost SWS and REM sleep occurs on postoperative nights 2–5, being later after major surgery. This coincides with the nadir of postoperative pulmonary function and several  studies have demonstrated marked hypoxaemia associated with the rebound of REM sleep. It was a logical step to attribute postoperative myocardial ischaemia, myocardial infarction, pulmonary embolism and cerebral disorder (delirium and cognitive impairment) to nocturnal hypoxaemia. However, a number of studies have failed to confirm these presumed associations,  although this does not exclude the possibility that the hypoxaemia may be important in some individuals. Key references Ambrosini MV, Giuditta B. Learning and sleep: the sequential hypothesis. Sleep Med Rev2001;5: 477–90 Dijk DJ, Lockley SW. Functional genomics of sleep and circadian rhythm: integration of human sleep-wake regulation and circadian rhythmicity.J Appl Physiol 2002;92: 852–62 Douglas N.Clinician’s Guide to Sleep Medicine. Edinburgh:Arnold, 2002   Ebrahim IO et al. The hypocretin/orexin system. J R Soc Med 2002;95: 227–30 Kryger MH, Roth T, Dement WC. (eds) Principles and Practice of Sleep Medicine, 3rd edn. Philadelphia: 2000. Nicolau MC et al.Why we sleep: the evolutionary pathway to the mammalian sleep pattern.Prog Neurobiol2000;62: 379–406 Saper CB, Chou TC, Scammell TE.The sleep switch: hypothalamic control of sleep and wakefulness.Trends Neurosci2001;24: 726–31 Shneerson JM.Handbook of Sleep Medicine. Oxford: Blackwell, 2000 Williams JM, Hanning CD. Obstructive sleep apnoea,BJA CEPD Rev2003; 3: 75–78

Looking for a hotel where kids are welcome? :: Essays Papers

Looking for a hotel where kids are welcome? GRAPH The well-known comic The Family Circus by Bil Keane, which is run in over 1500 newspapers, shows the hectic life of an American family, giving meaning to the saying, "Kids will be kids." It is based on the actual life of Bil Keane’s family and his experiences as a child. The most commonly noted features of his comic are the circular shape he often encloses the pictures in, and the dotted line that follows the children around, giving away their every move. Many other cartoonists try to capture the Family Circus mood by incorporating these features into their own works. GRAPH The Wyndham Hotels & Resorts advertisement uses this technique to show the path your child may take around the room of a hotel, where there is nothing else for them to do. It describes the creative and active characteristics of children, who require near constant entertainment that keeps them busy and uses their developing mind. At Wyndham hotels, they understand that keeping your children entertained is a challenging task for you, the parent, which is why they provide an activity package for your kids. The disapproving glare from behind the desk that is sometimes given to parents as they walk into a nice hotel with their three young children is often mirrored to pet-owners, which I can relate to. This gives you a feeling of insecurity and makes you feel unwelcome. I know I appreciate when the hotel at which I am planning to stay has a special feature for pets because then I know not only am I welcome, but that they also welcome my dog. The feeling is similar with parents wanting their children to be welcome. You know from watching Nickelodeon and Nick Jr. with your kids, how much they love Spongebob Squarepants. Moreover, you know that sleepovers are fun. Wyndham Hotels & Resorts also know this, which is why they are advertising this Spongebob Squarepants sleepover party package.

Benifits of Academic Globalization Essay

2. Introduction: Globalization is one of the most discussed issues nowadays. It has several branches which vary from economic, cultural, academic, and industrial and many more. However, the one that is increasing at a very high rate is academic globalization. Since academic globalization includes the act of studying abroad, it can be defined as is the act of traveling of students to study in a country other than the mother one. Nowadays, students are getting many Academic Globalization l 3 opportunities to study abroad, in addition to other reasons, which is why they are studying outside their home countries. â€Å"He [Wiladavsky] stated that 3 million students are now studying outside their home countries, a 57% increase from 2000† (Apurvadesai, 2010, p. 1). These numbers show the tremendous increase in movement of students around the world. Academic globalization has become one of the most debatable issues. People who are against it believe that once the students graduate and see many opportunities to work abroad they would not come back. On the other hand, people who are with it believe that it provides the students with better education and higher experience. In fact, academic globalization can be beneficial in several ways. 3. Literature review: Apurvadesia (2010), comments on the discussion of the World Affairs council which focuses on the rise of academic globalization. According to Wiladavsky, who was among the speakers, there is an increase in the movement of students around the world. Moreover, he discussed the concept of global ranking that motivates students to work and study harder to reach their goals and become part of the top class. In addition to that, Apurvadesia states that the idea of brain drain is actually brain circulation. Wiladavsky (2010), argues that countries should not be afraid from globalization. On the contrary, Wiladavsky tries to shed the light on the benefits of academic globalization. He believes that it helps in expanding knowledge and in trading of minds. Moreover, Wiladavsky tries to shed the light on the opposing point of view and give reasons behind the fear of globalization. Academic Globalization l 4 Wiladavsky (2010), focuses on why colleges should support globalization. Wiladavsky argues by believing that globalization of higher education helps in identifying talents. Moreover, he believes that successful competition is achieved by higher education. Goodman(2013), argues that Americans should study abroad in order to get  international experience. Moreover, he believes that student would appreciate difference and diversity through meeting new people. In addition to that, he considers that by interacting with people from different countries, students would be trained to all sectors of leaders. 4. Better education: One of the main reasons why academic globalization is beneficial is by offering a better education for the students. This is due to the fact that more opportunities and better experience are provided. 4. 1 More opportunities: Students get better education by having a wide variety of majors to choose where they fit. Some countries lack majors which are  available in others and thus, instead of doing a major that they are not interested in, they have the opportunity to study abroad the major they always dreamt of. For example, in Lebanon, petroleum engineering is not available; however, some students are interested in such a major. So instead of looking for another major to study, they can simply apply in another country which includes such majors. Moreover, a master degree is another opportunity provided in some countries and deprived in others. In developed countries such as USA or Europe, the master degree offered provides the students with better credentials. Students  Academic Globalization l 5 would be more knowledgeable and updated to recent discoveries. A student having a BS degree has less opportunity than a student having a master degree when applying a certain job especially, if the master degree was from a country offering a higher education. 4. 2 More experience: Another reason why students are provided with a better education is the high experience they get. The concept of brain circulation applies here, where students get different degrees from different countries. † A student may leave China, go to Singapore for an undergraduate degree, then to US for a Master’s degree, then  Australia to work for a couple of years, then back to China for a job with a multi-national company†(Apurvadesai, 2010,p. 2). In this example, Apurvadesai describes how having the opportunity to study in different countries provides the student with the higher experience and characteristics required for a job in a multi-national company. Moreover, living in a different country, having different culture, language, habits and lifestyle, increase experience. When students travel, they try to accommodate with the changes around them. This process provides them with higher experience when it comes to dealing with other countries. In addition to that, students will be provided with better communication skills. They would learn to speak new languages fluently due to practice and would be familiar with the demand of other countries. In this way, if there was a foreign customer, Academic Globalization l 6 the student will directly provide him/her with the service he/she is more likely to be interested in. 5. Expands global knowledge: Another reason why academic globalization is beneficial is that it helps in expanding knowledge across the world. This is achieved by discovering new talents. Some countries are deprived from a variety of domains. On the contrary,  when students travel to encounter their education, they would be exposed to a wide selection of domains. In this way, students would be able to discover new talents in them and introduce it to their local country. Moreover, academic globalization promotes the sharing of information between countries. When students get their education in a foreign country, they would be introduced to new concepts, studies and researches. People against academic globalization argue that the country offering the higher education takes away from the learning of the native country. However, introducing new concepts is not bad to other countries. In fact, as RAND economist James Hosek told the Cronicle of Higher Education that â€Å"When new knowledge is created, it is a public good and can be used by many†(Wiladavsky, 2010, p. 3). When students return back to their countries, they would share the knowledge they acquired and help in developing their nations. 6. Conclusion: In conclusion, academic globalization is a trend that is increasing at a very high rate. It is a one of the most debatable issues in the society. Some people are with it and think it is beneficial, while others are against it and think it is harmful. However, it can be beneficial in several ways. It provides better education for Academic Globalization l 7 students through having more experiences and opportunities. Moreover, academic globalization promotes global knowledge between different countries leading to the free trade of mind. In fact, people should support academic globalization to develop the whole world. 7. References: Apurvadesai. (May 15, 2010). Academic Globalization- The Emergence of International Universities. In Reading, Writing and Reflecting. Retrieved from http://apurvadesai. com/2010/05/15/academic-globalization-the-emergence -of-international-universities/ Goodman, A. E. , Berdan, S. N. (October 17, 2013). A Year Abroad vs. a Year Wasted. In The New York Times. Retrieved from, http://www. nytimes. com/roomfordebate/2013/10/17/should-more-american s-study-abroad/every-student-should-study-abroad Wildavsky, B. (January 5, 2010). Academic Globalization Should Be Welcomed. Not Feared. In Brookings. Retrieved from, http://brookings. edu/research/articles/2010/01/15- globalization-wildavsky. Wildavsky, B. (April 4, 2010). Why Colleges Shouldn’t Fear Global Competition. In The Chronicle of Higher Education. Retrieved from, http://chronicle. com/article/The-Global-Benefits-of/64932/. Academic Globalization l 8

Queen Of Katwe A Reflection And Comparison - 1003 Words

Queen of Katwe: A Reflection and Comparison Poverty. Sickness. Poor education. The people in the movie Queen of Katwe live a hard life, yet they are still happy and hard working. This movie has many important morals in it, but the one most important to the story line would be about overcoming obstacles. â€Å"In chess, the small one can become the big one. That’s why I like it.† This quote is about chess, but it applies to our lives too. Growing up is all about overcoming obstacles, and the characters in the movie faced many difficulties. Phiona, for example, overcomes the obstacle of the children s taunts when she first goes to a chess meeting. She goes back again and again and perseveres to get the practice she needs, and eventually becomes†¦show more content†¦Another similarity would be that the children really value the opportunities available to them. I really appreciate the christian school and the sports that are an option for me, because those things aren’t accessible to everyone, just l ike how Phiona and the other kids all value the game of chess and any education they can get. Even in vastly different situations there are always ways people can relate to one another and show their worldviews. The elements of worldview all bring up differences between the worldviews and ways of life in Uganda compared to here in Canada. Geography, time, knowledge, economy, society, and beliefs and values; Each of them are important in shaping our perspectives. The danger at night, hair cut short to avoid disease, and terrible floods are examples of geographical things that could make Phiona’s worldview different from mine. An important display of time throughout the movie is Phiona’s happiness. Near the beginning of the movie, a neighbor asks how her life is going, and she replies that it is fine. But after losing one of her tournaments she comes home and lays in bed, depressed. She does not respond when asked again how she is. After introducing the game of chess to her worldview, Phiona finds she is unhappy when she does not play it anymore. Eventually she plays again, and when she wins the championship, she is overjoyed. â€Å"Losses happen to everyone. But then we reset the pieces and