Plasmodium falciparum: The Causative Agent of Malaria :: Essays Papers

Plasmodium falciparum: The Causative Agent of Malaria Introduction The protozoan Plasmodium falciparum is responsible for causing 500 million cases of malaria per year as well as 100-200 million deaths per year worldwide (Kuby, p438). The majority of these deaths occur in sub-Saharan Africa, especially among malnourished children. Malaria is endemic in 92 countries, where 40% of the world’s population is at risk of the disease (WHO). Documentation of malaria occurs as far back as 4000BC, with mentions of the disease on clay tablets. The name of the disease originates from the late 1800’s and is derived from ‘mal aria,’ meaning bad air. There are four members of Plasmodium that cause malaria along with P. falciparum, with P. vivax, P. ovale, P. malariae (Schaechter, p450). P. falciparum is considered the most important as it is by far the most deadly species. The primary vector of P. falciparum is the female anopheline mosquito, which uses humans as a host for blood meals. The male anopheline feeds only on plant juices, and is not a competent vector for the disease. Humans compromise the only suitable reservoir in the enzootic cycle of the protozoa (Schaechter, p450). Both the P. falciparum and Anopheles gambiae genomic sequences have been recently published (Gardner et al. Holt et al. 2002), thus giving rise to invaluable tools in the development of new and much needed anti-malarial drugs and vaccines, as well as new targets in mosquito control. Encounter and Entry The female Anopheles interacts with the human host by piercing the host’s epithelium and releasing Plasmodium falciparum from its salivary glands into the human bloodstream while obtaining a blood meal. The form of P. falciparum injected into the human host is the sporozoite stage in the pathogen's life cycle (Kuby, Schaechter). As humans compromise the only competent reservoir for P. falciparum, the female Anopheles must have acquired the protozoan via blood meal from another infected human 9 to 17 days prior to being able to infect a new human host. Spread and Multiplication The sporozoites enter the human host and then travel via the bloodstream to the liver, where they enter liver cells and mature into schizonts after a period of 8-14 days. Sporozoites are covered with a 45-kDa protein called circumsporozoite which mediates adhesion to hepatocytes (Kuby, p439). Schizonts are released into the bloodstream as merozoites after a week, and are capable of entering and lysing erythrocytes and thus causing disease.

CDR Engineer

I had worked as vascular support engineer to support the cardio vascular imaging systems in the region assigned to me. I had taken the responsibility to manage the overall service delivery and ensure the customer satisfaction to the optimum level. I provided expert phone and/or onsite technical support to field service and customers to minimize equipment downtime while improving customer satisfaction. I had taken additional responsibility to connect and configure all the imaging systems to the remote online centre through broad band and virtual private network connectivity.Since I was the technical support for the region, I had the responsibility to take care of the difficult technical issues which could not be solved by the field service engineers. I had taken initiative to perform the power and grounding audit for the southern region of India. I had been responsible to build the technical support team. i had reported on solid line to the regional service manager and dotted line to all India service manager. I had been assigned to handle and solve the frequent failure in mobile cardiac catheterization imaging system in one of our important end user site.This system had multiple breakdown and image quality issues. I had to solve the issue and bring back the customer confidence level in our equipment quality and service delivery. I had taken it as a challenge and started the work at the site. This Free CDR Template is brought to your courtesy of gettingdownunder. com – Free Australian Immigration advice and resources for those looking to make the move down under. Personal Workplace Activity: Prior to start the service work , i had gone through the service log books and the error log files of the system to know the root cause of the multiple  and frequent failure of the system.The data analysis from the log book and the service files, I found some serious power quality and grounding issue on the site. I had decided to conduct the preliminary power and qu ality audit in the site. I inspected the power distribution panel and found the power cable size was under rated and unable to take the load. During the imaging system usage these power feeding cables started heating up and resulted in cable insulation meltdown. So I recommended to change the power feeding cables with the correct size to withstand the load.I measured the ground impedance and found it extremely high. So I inspected the earth pit and found the bonding between the earth wire and the earth rod open. The electrical maintenance department of the hospital informed and corrective action had been taken immediately. Once the corrective action was taken, I measured the ground impedance again and found within the recommended level. I had booted up the imaging system and run the system diagnostic tests to isolate the problem. From the diagnostic test results, I suspected the problem in the High voltage and the control electronics.The high voltage circuit consists of inverter cir cuit, HV voltage tank with the filament transformer, HV cables for the anode and the cathode, and the x-ray tube. The block diagram as follows Since there was no x-ray output from the tube, I started the troubleshooting from the snubber board which feed the primary side of the HV tank. The snubber board contains four Insulated Gate Bipolar Transistors that switches the very large currents applied to the input of the large step – up transformer in the High voltage tank.This pcb is designed with very low DC resistance and inductance to minimize the voltage drops at high currents. The resistorcapacitor-diode network on the board is used to damp the IGBT switch spikes. P. E. 2. 8 Due to the absence of x-ray generation, the system displayed low MA and low KV error message on the console monitor. This is due to absence of output from the secondary side of the HV tank. So I switched off the entire system and I checked the 400v, 70amps semiconductor fuse on the snubber board and foun d it defective.This fuse might be blown due to the fault current generated from the x-ray tube spit. The x-ray tube spit is generated in the glass tube insert of the x-ray due to the formation of metallization on the glass walls. Then I checked This Free CDR Template is brought to your courtesy of gettingdownunder. com – Free Australian Immigration advice and resources for those looking to make the move down under. resistance between IGBT emitter terminal and the chassis ground with the true RMS multimeter and found short. This indicated the damage of wire insulation in the IGBT.I found both the IGBT module faulty with the emitter to chassis ground short. So I replaced the IGBT module with the new one. After the replacement of IGBT module, I removed the anode and cathode HV cable on the tube side and inspected the HV cable connector and found lot of carbon deposits due to the tube spit. The carbon deposit on the HV cable pins hamper the effective conductivity, so I cleaned th e connectors with Chemotronics Electro-wash solution. I checked the HV receptacle well on the xray tube and found it completely damaged.The insulation between the filament supply and grid was completely lost. So I found it not repairable and the entire x ray tube assembly needed the replacement. I replaced the x-ray tube assembly with the new one. Before the power on, I decided to double check the HV tank which is the main part of HV Circuit. The HV tank develops the extremely high voltage necessary to operate the x-ray tube (up to 125kv). The tank includes resonant step up transformer, high voltage rectifiers, x-ray tube filament transformers, output ma and KV sensors and connectors.I checked the rectifiers and the primary and secondary windings of the transformer for any defect and found everything ok. P. E. 2. 11 Then I decided to do the KV in Open Loop test in HV tank. So I removed the HV cables on the HV tank output and filled the HV tank output receptacle with mineral oil. Lat er I switched on the system and run the KV open loop test and it passed ok. Then I restored the HV cable connection between the tank and the x-ray tube in system off state. P. E. 2. 12 The x-ray tube and IGBT module replacement required the following calibration and adjustments for the normal and safe function of the systemIGBT Module Dead time wave form adjustments Filament Calibration KV and MA metering calibration Radiation dose calibration First I had to adjust the dead time between the KV drives signals on each of the IGBT pairs to proceed with the other calibration properly. The improper dead time adjustment might lead to damage of IGBT and the Generator driver board (which supplies the trigger pulse to the IGBT module). I connected the dual trace oscilloscope on the test points on the Generator driver board and observed the waveform of both the IGBT drive signal.I found the drive signal between the base and emitter of the IGBTs out of tolerance during the peak load. So this m ight lead to cross-conduction in the IGBT module and the destruction of IGBT module. This Free CDR Template is brought to your courtesy of gettingdownunder. com – Free Australian Immigration advice and resources for those looking to make the move down under. The Generator driver PCB’s primary job is to convert the KVP drive signal from the High Voltage Supply regulator PCB to the levels necessary to drive the IGBTs on the SNUBBER PCB.So I connected the oscilloscope in the high voltage regulator PCB test points and found the amplitude and frequency of the waveforms normal. So the root cause was isolated and identified with the Generator driver PCB. The problem was found on two of comparator’s output drives the gate transformers, which provide isolation from the high current circuitry and from high voltages present on each of the IGBT module. The defective comparator IC chips were removed and replaced with the new one. After the replacement of the comparator IC ch ips the drive signals were found normal.I had proceeded with the IGBT dead time adjustment with the scope meter connected with the generator driver PCB and set it within the safer limit. I had checked the waveforms on the scope meter during the peak load condition and found ok. I performed the filament calibration at different KV and Ma station and updated the system filament drive database. This updated database might be used by the filament driver PCB to drive the filament transformer to output correct x-ray tube current according the radiation technique.After the filament calibration, I adjusted the KV and MA metering adjustment to sense and display the correct KV and MA value of X-ray tube on the console during the time radiation exposure. Also I aligned the X-ray beam with the image intensifier in different Field of views. Subsequently I had run the collimator calibration for adjusting the collimator blades in different field of views. The camera Iris opening is adjusted to set the radiation dose at a safer limit recommended by the manufacturer. The image quality was tuned to optimum level. SummaryI had checked and tuned the imaging system for the optimum image quality. I run different exposure techniques with the Image Quality Signature Test Phantom and found the values within the specification. The customer was delighted with the performance and the This Free CDR Template is brought to your courtesy of gettingdownunder. com – Free Australian Immigration advice and resources for those looking to make the move down under. image quality of the system after the completion of the service work. It was a challenge for me to troubleshoot the system with multiple failures.During the course of trouble shooting I analyzed the circuits and isolated the problem areas with the help of the knowledge acquired from my field experience and engineering course. I had learnt and applied different troubleshooting techniques to solve this issues. In nutshell I had cons idered this project as important milestone in my learning process and in my career advancement. This Free CDR Template is brought to your courtesy of gettingdownunder. com – Free Australian Immigration advice and resources for those looking to make the move down under.

Twin Study

1. Methods and results In this study, Thomas Bouchard and David Lykken, along with their associates at the University of Minnesota, were attempting to prove if nature is the determining factor in a person’s personality or if it really is the nurturing environment. They wanted to see if twins who were separated at birth and raised in different environments would still have similar personalities, which support the theory that a person’s genes has more impact on a person’s character than the environment.In order to study their hypothesis, Bouchard and Lykken located identical twins that were separated by birth due to adoption and spent a week conducting various tests; four personality trait scales, three aptitude and occupational interest inventories as well as two intelligence tests. Through these examples and other tests, Bouchard and Lykken complied copious amounts of data on the twins. The results of the study favored the nature theory in that an overwhelming pe rcentage of the twins had similar results and personalities despite having never grown up together. . Analysis It does appear that this study’s results proved whether nature or nurture is important in the development of a person’s personality. At least this seems to have been proven in the instance of identical twins. However, there was no mention of research done involving twins raised in the same household to compare to this study’s results. I do believe that the experiment was done properly in coordination with the scientific method but that various psychologists should have replicated the experiment numerous times over time. . Criticisms As with all published findings, there were those who argued against the claims made by Bouchard and Lykken. Some members of the psychological community believed that what was published was incomplete and therefore cannot be regarded as true unless all the results are made available. In addition, some critics claim that Bouch ard and Lykken are guilty of the â€Å"equal environment assumption† which is that identical and fraternal twins are treated equally and raised in identical environments.This assumption is untrue as parents treat fraternal twins, two separately fertilized eggs versus one that split, as complete different individuals like any other siblings born at separate times. Other psychologists agreed with Bouchard and Lykken and even completed their own studies about genetic influence on people’s personalities as well as choices, and many of these studies had similar results, thus further supporting Bouchard and Lykken. 4. ConclusionThe overall meaning of this study is that the debate of nature versus nurture continues in the field of psychology and it is more a matter of interpretation of data and personal belief rather than something set in stone. Psychologists continue to follow the study’s example by investigating the impact of genetics on a person’s choices and actions such as whom they fall in love with and other complexities of human behavior. This study changed psychology in that there was a new element, genes, for psychologists to analyze for explanations about the human psyche.

ArticleS Analysis Essays - Black Sitcoms, The Cosby Show

Article'S Analysis Essays - Black Sitcoms, The Cosby Show Article'S Analysis In Jacqueline Bobo's article, The Color Purple: Black Women as Cultural Readers, it is discussed how black women create meaning out of the mainstream text of the film The Color Purple. In Leslie B Innis and Joe R. Feagin's article, The Cosby Show: The View from the Black Middle Class, they are explaining black middle-classed responses to the portrayal of Black family life on The Cosby Show. In their articles, Bobo, Innis and Feagin are investigating the representation of race, particularly African American race, in the mass media. However, these two shows are better portrayed than what was seen in the first article. This article Midnight Ramble portrays a much earlier media perception of African Americans. The information shows the first blacks in films, as well as the white actors who were painted up to portray the black characters. Midnight Ramble occurred between WWI and the 1950's. This, while not an excuse, does at least show that things have changed some. The chief concerns of the investigations of the articles, lie in how African Americans deal with the way these representations portray them individually and their social group as a whole. This paper's purpose is to compare the issues in each article and analyze the larger sociopolitical implications of these media representations. In Bobo's article, the chief concerns of the author are the savage and brutal depiction of black men in the film, black family instability, and the way that black women embrace the film and use their own reconstructed meaning of it to empower themselves and their social group(Bobo, 90-92). Film, as a medium, starts out with many potential limitations and problems when it comes to representing a whole race of people. No two people are exactly alike no matter what race they come from, so there is no one film that can represent all people. Unfortunately, many people believe that this is possible. Some believe that a certain depiction of black people characterizes all black people, which is certainly not the case. This is dangerous because it involves stereotyping and discrimination. The viewing public pays for movies, therefore, movie producers have to tailor their product so that the majority of viewers will enjoy, and agree with their product, so that the majority of viewers will enjoy, and agree with the ideas behind the film. The majority still, almost always means white America. Even African American based movies are made for white audiences. The representation of blacks in this type of environment does not always portray the real African American person. The film The Color Purple has been the center of controversy since it was made in 1985.many feel that the film is a bad portrayal of black family life, and that it is stereotypically portraying black men as evil and brutal who imprison and abuse women. The main purpose of Bobo's article was to find out why black women loved the movie so much and if they saw the film as helping or hindering their cause. Bobo did find that while many black women loved the movie, they found things inherently wrong with the way black men were portrayed. They did find the film positive, though, because it did portray black women in a more positive way than most other films. The women found power in the film and were able to identify with this search of power and their own identity. The Color Purple presented a new type of feminism to black women who were used to seeing black women characters portrayed as slaves, maids, or nannies. The women saw the film as a little bit of truth wrapped in a blanket of stereotypes (Bobo,102). They did believe that it was a story that needed to be told. The larger implications of The Color Purple are very serious. Black family life is presented as dysfunctional. Women are seen as fragile and easily abused by their men. And, even though it is suppose to be a middle classed family, it is portrayed as a lower classed family. In Innis and Feagin's article, the chief concerns of the authors are how black middle classed people are viewed on television, particularly, on The Cosby Show. Unfortunately, television presents many potential problems. This occur because

Perl Array unshift() Function Tutorial

Perl Array unshift() Function Tutorial Perls unshift() function is used to add value or values onto the beginning of an array (prepend), which increases the number of elements. The new values then become the first elements in the array. It returns the new total number of elements in the array. Its easy to confuse this function with push(), which adds elements to the end of an array. Picture a row of numbered boxes, going from left to right. The unshift() function would add the new value or values on to the left side of the array, and increase the elements. In the examples, the value of myNames becomes (Larry, Curly, Moe). The array can also be thought of as a stack- picture a stack of numbered boxes, starting with 0 on the top and increasing as it goes down. The unshift() function would add the value to the top of the stack, and increase the overall size of the stack. You can unshift() multiple values onto the array directly: Or by unshift()-ing an array:

The Dowry system in India Research Paper Example | Topics and Well Written Essays - 1250 words

The Dowry system in India - Research Paper Example Kautilya believed that there is absolutely no guilt for a wife to project such property regimes of hers in maintaining her son or even her daughter-in-law. One should not forget her own role in essence as well (Nazzari 1991). The dowry was a security that the girl would take with her into her new life in case of any adversity that may come. It was also a practice that would take place only among the wealthy families, but today it has seeped down to all levels in the Indian Society. The dowry system might have started as a sign of Good Blessings from the bride side, but today it has become a social evil which have taken the lives of many women all across India. The concept of dowry, somehow, evolved in to a practice in which the giving of dowry has become a compulsory act, which if not completed could mean that the girl is either not accepted or she is tortured after the wedding by her in-laws (Luthra 1999). The fear of â€Å"No Dowry, No Marriage† is too far spread in India. It was this social evil that resulted in the killing of Infant girls as soon as they were born, or having a low status as compared to the male siblings in the family. The birth of a girl became synonymous with the burden and cost of the dowry that she would be worth when her time for marriage would come. The concept of marriage however by the twenty first century became so commercialized that the grooms worth actually started to be determined by not only class and caste, but also by his qualifications and the prospect that he may have in the employment market. The highly prospect the groom is, higher is the expectation of the dowry. According to Leela Mullatti â€Å"the custom of dowry has taken the form of a market transition in all classes and castes irrespective of the level if education† (Shurmer-Smith 2000). The practice almost seems like that the bride’s family are suppose to keep the grooms family entice with the supply of the goods in the form of dowry and then

Stereotype paper Essay Example | Topics and Well Written Essays - 750 words

Stereotype paper - Essay Example that sometimes, maybe many times, we are actually just as guilty as the next person of making incorrect snap judgments based upon another person’s appearance alone rather than any inherent qualities. These judgments are based more upon what we understand about that type of person from what we’ve been taught or by comparing them with other elements of our experience. Many of these understandings are shaped by the media outlets we pay attention to. I never believed I was a very judgmental person and didn’t really feel I acted on stereotypes until I had an experience that opened my eyes. At the time, I was working in an auto parts store and was the only person manning the store when a new customer walked in. It was a woman and, although I didn’t really stop to think about my reaction to her, I realize that it was based mostly on what I understood of this kind of woman on how her type was portrayed in the movies. There were few facts involved in my decisions regarding the girl. The woman was blonde, skinny, young and dressed fashionably well. Her big, blue eyes seemed overwhelmed at the materials in the automotive shop and she wandered around the aisles as if lost. Without even thinking about it, I made an instant assessment of her based upon her looks that qualifies as stereotyping. Her appearance was really the only fact I had to go on before making my assessment, but this was enough to me to feel as if I had correctly identified her personality and ability. The other fact I was working on was the fact that I had very few female customers. My typical customers were men, ranging in age from teenage through old man, and they were usually dressed in oil-smeared clothes that had little resemblance to their original color or shape. The few women who came into the shop were regulars and they were usually only distinguishable from the men in the length of their hair and the higher pitch of their voice. Comparison to what I knew was also strongly