Saturday, October 5, 2019

Elevator pitch Essay Example | Topics and Well Written Essays - 250 words - 1

Elevator pitch - Essay Example The government will profit when the Americans spend more money in the country. Everything comes down to creating employment and employment can be created should the government support small scale industries. Small scale industries are more than capable of creating a plethora of jobs. This is how one initiative by the government can change the fortune of the nation. The economy of America is yet to recover from the recent setbacks, it is important for it to recover only then will more jobs be created and more Americans will get employed. Structural troubles are haunting the economy, the housing trouble for instance which was also the main reason for the recent recession impacted the economy of America severely. Americans who had borrowed money to buy houses failed to return that money to the banks as a result of which there was very little liquidity and the economy was greatly affected. â€Å"Uncertainty is natural, of course. The future is always uncertain. But there is good uncertainty and bad uncertainty, much as there is good cholesterol and bad cholesterol. Good uncertainty, for example, presents opportunities for profit. Bad uncertainty arises largely when investors and entrepreneurs have very real questions about the consequences of government policy.† (Promoting Job Creation) To conclude it is very fair to say that the government has to take initiatives and create jobs for the unemployed Americans and this will only happen when the economy of America recovers from the recent setbacks. Hopefully it will happen soon and the unemployment rate will be under control once

Friday, October 4, 2019

Annotated Bibliographies Essay Example | Topics and Well Written Essays - 750 words - 1

Annotated Bibliographies - Essay Example Onjira and Gilbert (2009) illustrate the affordances of machine-processable competency modeling. They argue that machine processing is invaluable in e-learning and assessment. They emphasize its effectiveness in e-learning. In addition, Onjira and Gilbert (2009) present the competency model’s affordances in generating questions, distractors, and adaptive query sequences. In the article, they conclude that using machine-processable competency overcomes many limitations in interoperability, reusability, and portability. They illustrate that printing of non-English characters, deploying computers in language classrooms and developing language software are now possible because of advanced technology. The article by Fischer elaborated the role of technology in language learning. Smith and Schulze (2013) discuss replication while highlighting its benefits and possible causes of misunderstanding. They argue that not all studies can be replicated, but the existence of replication connotes maturity of the field. Rabuzzi illustrates that dismissal state of STEM (science, technology, engineering, math) education is reported every week in the U.S. according to him, the risks in STEM subjects are because of the post-Cold War economic competition (Rabuzzi, 2014). Rabuzzi argues that improving STEM performance will foster talents of citizens as well as retain their world standing. He also argues that erasing the false divide that exists between scientific inquiry as well as humanistic learning will boost science education. Hughes, J. (2013). Descriptive Indicators of Future Teachers’ Technology Integration in the PK- 12 Classroom: Trends from a Laptop-Infused Teacher Education Program. J. Educational Computing Research, 48(4) 491-516. Hughes claims that integration of mobile technologies with professional teacher preparation will advance learning from one discipline approach to integrated learning approach. In connection with this claim, Hughes

Thursday, October 3, 2019

Map of the occupied Germany Essay Example for Free

Map of the occupied Germany Essay The map presented above has been reproduced from Wikimedia Commons. It shows the four zones which were occupied by Great Britain, France, the United States, and the USSR. It also shows the location of Berlin well inside the Russian zone. The inset shows how the city of Berlin was divided among the four occupiers. Just by looking at the geographical location of Berlin, one could immediately see that the carriers of supplies (like food, medicine, and fuel) which were coming from the western zone and meant for the residents of the western sectors of Berlin had to traverse through a significant portion of the Russian zone before they could reach their destination. The Berlin Blockade, therefore, threatened the very survival of the Berliners who were living in the western sectors. This was realized by Stalin who exploited the situation in order to exert pressure on the western powers into renegotiating the German problem. This was what worried Governor Clay. He was well aware that the 2. 5 million residents of the western sectors could not survive longer than five weeks without new shipments of supplies. The blockade first surprised then confused the officials of the western powers. British foreign minister Bevin declared that despite the blockade, they should go forward with the plan of creating a West German state. Military Governor Clay recommended the use of an armored convoy to transport supplies through the Russian zone. However, his recommendation was turned down for fear that it would provoke a war with the USSR. In the end, the suggestion of Bevin to airlift the supplies was favored (Wilde). The planes carrying the supplies would fly over the Russian zone using the three air corridors which were opened under an agreement with the Russians after the war. These were: the â€Å"Frankfurt/Main-Berlin air corridor, the Hannover/Bueckeburg-Berlin air corridor, and the Hamburg-Berlin air corridor† (Berlin Information Group). On July 2, 1948, British Lt. General Brian K. Robertson conferred with the leaders of the United States and France after which he demanded the lifting of the Berlin Blockade. However, on July 14, the USSR responded by saying that the United States, Great Britain, and France had lost their right to stay in Berlin. The Russian response also justified the blockade by stating that its objective was the protection of the â€Å"economy of the [S]oviet zone. † According to the Russians, the creation of a West German state and the issuance of a new currency violated the agreements of the â€Å"Big Four† with regards the occupation of Germany. Hence, by violating the agreement, Russians claimed that the United States, Great Britain, and France effectively rendered their right to take part in the occupation and administration of Berlin null and void. The Russians also emphasized that since Berlin was located inside the Russian zone, all of Berlin (including the western sectors) belonged to the Russian zone. The western powers reacted to the Russian allegations during a meeting among the delegations of the United States, Great Britain, and France which started on July 15. Their joint response stated that â€Å"Threats, pressure or other actions† could not pressure them into leaving Berlin. On July 17, William J. (Wild Bill) Donovan, a former Major General who was the director of the Office of Strategic Services (OSS) during the war, declared that â€Å"The place to make a stand against Russia is right here in Berlin. This is not a Cold War. It is Hot as Hell† (The Berlin Airlift Veterans Association).

Wednesday, October 2, 2019

History of the Barcode and Its Applications

History of the Barcode and Its Applications INTRODUCTION The innovation of barcodes has really emerged as one of the biggest innovation and it has been very influential for the inventory handlers. Especially if we look at the supermarkets it is a very tough business because it involves a lot of inventory handling. Maintaining inventory which is not too much and not too less is a very critical issue for the owners. But with the advent of this automatic readable technology things are quite easy and speedy nowadays. This paper tells us that how initially supermarkets had to manually count and keep track of their inventories and not only supermarkets but all the industries who involve handling of large amount of inventories had to come across high costs and it also took a lot of time, but the emergence of this remarkable innovation has speed up the processes which has eventually helped lowering costs, saving time and last but not the least in satisfying customers. This paper also focuses on the different types and dimensions of innovation and explains that how the innovation of barcodes fit into those dimensions. 2 BARCODES Standardized tags are the most prevalent of the programmed information passage strategies. It is an example of parallel bars and spaces of variable widths orchestrated in a particular decided example to speak to a comparing number, letter, or image. The data in a standardized tag is held in the relative thickness and relative position of the lines and spaces inside the particular information characters. Scanners change over the bars and spaces into usable data for information passage. HISTORY While it may appear as though standardized tags have been with us everlastingly, standardized tags didnt generally have an effect until the 1970s. It wasnt until 1974 that the first standardized identification scanner was utilized and the first item bar coded. Be that as it may the thought had been around for a short time. In 1932, Wallace Flint proposed that a mechanized retail checkout framework may be practical. While His idea was considered unworkable, Flint kept on supporting the thought of computerized checkout all through his vocation. Actually, Flint, who happened to turn into the VP of the relationship of evolved ways of life around 40 years after the fact, was instrumental in the improvement of the UPC (Universal Product Code). Throughout the 40s, 50s and 60s few code organizations were created including a bulls-eye code, numeral codes, and different arrangements. Retail applications drove the early innovative improvements of bar coding, yet mechanical applications soon emu lated. 3 Initial Uses of Bar Codes In 1948, a nearby natural pecking order store holder approached Drexel Institute of Technology in Philadelphia getting some information about exploration into a system for consequently perusing item data throughout checkout. Bernard Silver, a graduate understudy at Drexel Institute, alongside individual graduate learner Norman Joseph Woodland, teamed together to create an answer. Forest initially proposed utilizing ultraviolet light delicate ink. A working model was manufactured yet dismisses as being excessively unsteady and lavish. On October 20, 1949, Woodland and Silver succeeded in building a working model depicting their development as article arrangement†¦ through the medium of distinguishing examples. On October 7, 1952, they were allowed a patent for their Characterizing Apparatus and Method. Deliberations to create a working framework quickened in the 1960s.bar coding was initially utilized industrially as a part of 1966, yet to make the framework satisfactory to the b usiness overall there would need to be an industry standard. By 1970, Logicon Inc. had created the Universal Grocery Products Identification Code (UGPIC). The main organization to deliver standardized identification supplies for retail exchange (utilizing UGPIC) was the American organization Monarch Marking (1970), and for modern utilize, the British organization Plessey Telecommunications (1970).in 1972, a Kroger store in Cincinnati started utilizing a bulls-eye code. Throughout that same time period, an advisory group was structured inside the staple business to choose a standard code to be utilized as a part of the business. IBM proposed a configuration, based upon the UGPIC work and like todays UPC code. On April 3, 1973, the board chose the UPC image (focused around the IBM proposal) as the business standard. The accomplishment of the framework from that point forward has prodded on the improvement of other coding frameworks. George J. Laurer is viewed as the designer of U.p.c. alternately Uniform Product Code. In June of 1974, the first U.p.c. scanner was introduced at a Marshs general store in Troy, Ohio. The main item to have a standardized tag was Wrigleys Gum. 4 Today Today, standardized tags are all over the place. Rental auto organizations stay informed concerning their armada by method for standardized tags on the auto guard. Aerial transports track traveler gear, lessening the possibility of misfortune. NASA depends on standardized identifications to screen the many high temperature tiles that need to be supplanted after every space shuttle excursion, and the development of atomic waste is followed with a scanner tag stock framework. Standardized identifications even show up on people! Style fashioners stamp standardized tags on their models to help direction design shows. (The codes store data about what equips each one model ought to be wearing and when they are expected on the runway). New era of Bar Codes opens potential outcomes for new applications, for instance Data Matrix permits a lot of data to be put away in a little space. This is for instance is utilized within health awareness division. Scanner tags are as of now the best known a nd most generally utilized programmed ID engineering. Future The eventual fate of programmed ID, on the other hand, is likely in radio recurrence (RFID). Modest transmitters implanted in things dont oblige a viewable pathway to the scanner, nor are they subject to corruption by presentation. Effectively being used in retail locations to help forestall shoplifting and on toll streets to speed activity, the essential obstruction to more extensive utilization of RFID has been the expense of the silicon chips needed. Today, the five-penny chip is close nearby. On the off chance that the expense might be lessened to short of what one penny a chip, later on your breakfast oat box will be a radio transmitter. 5 THEORIES OF INNOVATION Developing a new product is not that easy as it may seem to be, it requires a lot of continuous effort and determination on the end of the producer. An innovative product is of great benefit not only to its users but it is of great value to the innovating firm as it generates higher value for the firm and allows the firm to enjoy a better competitive position in the market. But it should be kept in mind that developing an innovative does not means that the struggle has ended. When an innovative product enters a market it creates a lot of hype but as the time passes it may start to lose its uniqueness and its exciting features may start to fade, this might be due to competitors copying the product or the simply the users get bore of using it. Therefore, the companies have to strive continuously to maintain their innovation for a longer period of time. Similarly innovation can be in the form of better services which provide better quality and customer satisfaction at a price lower than the competitors. Financial markets involve service innovation as the try their level best to facilitate and satisfy their customers. But the innovative edge and this level of high satisfaction among the customers remains until the innovation is not imitated by the competitor. There remains a lot of pressure on the innovators to innovate continuously to maintain their strategic edge over the other firms and in order to do so some firms may look to bring some changes to the product design, some ponder over the quality, some try to wipe out their enemies by controlling and lowering the cost and some of the innovating firms look to bring changes into their processes. 6 So, the only way of maintaining your strategic advantage is to innovate continuously and there are several theories for it. S-curve The S-curve measures the adoption rate of an innovation. At x-axis we measure the time and the percentage of market penetration is measured at the y-axis. At its early stages the adoption rate of an innovation is at the lower side and only the innovators are accustomed to the product, afterwards some early adopters emerge as they try using the new product and finally the late majority and laggards come into act, all this pattern is visually shown by the S-shape curve. The process of innovation basically starts with a new idea. The stage is very crucial as there are very key questions to be answered by the innovating firm which include funding and testing of the new product as early adopters are ready to give a try to the new technology or new product or service. After the early adopters firm makes decisions on its target market and it is the point when the new product moves from specific segments to more diverse segments and the company starts shifting towards mass production which ultimately leads to standardization. Due to standardization market tends to mature. At the latter stage people who avoid risk or simply you can say late adopters join the party and start using the product. At this stage the only room left for innovation is in the form of design, quality and economies of scale which is known as incremental innovation. 7 Technology Push: A technology push is a situation when the firms are forced to carry out an innovative process due to some emerging technology or due to a new combination of existing technologies. Sometimes in order to stay in the market race and to maintain a good strategic advantage companies have to carry out an innovative process unwillingly, for instance if your competitor deploys new quality which enhances quality of the final product and increases its chances to be praised highly by the end users then you are forced to innovate and bring some new and exciting to match or surpass your competitor. On the other hand sometimes technological opportunities may provoke or push firms to innovate. Market pull: The ultimate goal of an organization is to maximize its profit and it is only possible if caters its market in an efficient manner. Sometimes need for a new product or solution to a problem may be demanded by the customers themselves. The need is identified by potential customers or market research. This situation is referred to as Market pull. Disruptive innovation The theory of disruptive innovation involves introduction of a product which is primarily aimed at providing simplicity, convenience, accessibility and affordability in an environment where 8 intricacy and high costs are the dominant factors. Initially disruptive information is applied to niche market but eventually the new concept or technology transforms the whole industry. Disruptive innovators are not regarded as breakthrough forces but they are considered a positive force they may not help in making a product or service better but they surely contribute a lot to make sure better accessibility and availability of the product or service. Breakthrough innovation As the name suggests breakthrough innovation is something like ‘’out of the box’’ solution for any problem which cannot be compared to existing technologies or methodologies. Mostly the research and development departments are responsible for this innovation and the process is carried out in the labs as it requires constant research. The innovators looking for breakthrough do not have customers in mind because this innovation is initially focused at the supply side of the supply chain and then if required the technology is pushed on to the customers. APPLICATION OF THEORIES The innovation of barcode according to me should be termed as process innovation as it totally changed the way the inventories were managed before, specially the cumbersome job of the supermarkets has seen a great relief by the advent of this automatic readable technology. Barcodes have reduced time and saved a lot of costs, initially supermarkets owners had to count all the items on their shelves to stay updates with the inventory status and they had to employ several people for this task which obviously resulted in higher costs and it suck a lot of time also. 9 This for companies has not only reduced costs or decreased the time but it has also been influential in satisfying customers, the customers do not have to wait for long for the bills on the counter, the barcode reader is flashed on the barcode which is on the product and the price of the product emerges in seconds on the cashier’s computer screen. According to S-curve initially the users of bar-coding system were limited as the early adopters of this remarkable innovation were the supermarket owners who actually initiated or felt the need for such a product but as this technology started getting recognition it was seen as a big hit and it was deployed by each and every industry which had to deal with bulks of inventory. The innovation of a barcode is a technological development as it completely revolutionized the way the inventories were handled. Barcode is a pure case of market pull as it was initiated from the market as a president of a supermarket felt the desperate need of this remarkable innovation. Apart from that it is also disruptive innovation as it has made the handling of inventory more convenient, accessible, time saving and less costly as it was ever before. Barcode can also easily be termed as breakthrough innovation because it has been a real out of the box thing, no one at the time of its introduction would have thought even for a second that something as remarkable as barcodes will come and ease up the complex lives of the inventory handlers. 10 Bibliography Brown, S. A. (April 2001). A History of the Bar Code. Herstatt, P. D. (August 2000). Management of â€Å"technology push† development projects. Ryan, V. (2013). WHAT IS MARKET PULL. Seideman, T. (n.d.). Barcodes Sweep the WorldTony Seideman. Tumati, P. (n.d.). Types of Innovations.

Earthquake Engineering :: Earthquakes Earth Geology Essays

Earthquake Engineering Earthquakes are vibrations felt at the surface of the earth which are caused by disturbances of the energy in the earth's interior. These vibrations are known as seismic waves. (Skinner Robinson McVerry 1) There are different type sof seisimc waves such as Primary (P) waves, whcih travel the fastest, Secondary (S) waves which cause the earth to vibrate vertically, Surface (L) waves. P and S waves are "affected by changes in the density and the rigidity of the materials through which they pass." (Columbia Encyclopedia) Earthquakes vary in their intensity and duration. Often times they are strong enough to cause massive destriction. Tall buildings often suffer as a result of these natural disasters. In recent years this has become a larger and larger threat with both the number of large buildings, and their number of occupants increasing. In an effort to try to minimize the damage caused by earthquakes many some engineers focus primarily on designing and constructing ea rthquake resistant buildings. Earthquake engineers have gathered much of their information from analyzing past earthquakes, and learning which buildings can and can't withstand the tremors. The goals of these engineers is to design buildings that can withstand moderate earthquakes and obtain minimal damage, and that the buildings will not collapse lowering the probability of human deaths. Authorities have attempted to implement codes or regulations, but that has proved to be very difficult tasks becasue there are many variables that effect the dynamic response of buildings. One way to try to avoid disaster is to evaluate seismic risk is to look at a buildings hazards, exposure, vulnerability, and location. Hazards are, for example, landslides ad soil type. Exposure is a building's occupancy and function. Vulnerability is the expected performance of a building's system, and location is how often earthquakes occur in the area. (Lagorio) Some other things that have become evident are that geometric simplicity and symmetry are key to constructing an earthquake resistant building. Simplicity often leads to symmetry, and in turn symmetry tends to decrease the likelihood of a concentration of mass. This idea of lighter buildings being safer can be explained mathematically using the formula F=MA. To understand how this formula works it is pertinent to recognize that earthquakes alone do not cause damage because all they provide is an acceleration.

Tuesday, October 1, 2019

Patch Adams

Patch Adams Patch Adams is very interesting to watch. From the beginning of the story, there is the willingness of the viewers to watch the movie till the end. It is simple but not on its meaning. It does not only talk about the life of patch, the doctors, patients, students but also the nurses who are always in the side of the patients. Its focus is more on personality. Meeting people that will pull you down then lift you up and changing their views is one of your amazing deeds and help.And even there are those people who helped you to build your dreams they must never be the reason to break it instead they will be the one who strengthen you to pursue it, even if they will be gone someday. It has a message that is no matter what; don’t let something to discourage you from what you love and who you are. It is not just any movie that will make you cry because of sad parts but because of the fact that even you have done good things it might followed by bad happenings. There are things that can not be prevented.It is the best example for many cases of being confused in oneself, not only in mental capacity of thinking but also the ability to know yourself. Patch was helped by this brilliant man, Arthur Mendelson, to see through problems which made me realize on simple things. Patch is not just an ordinary man. He knows the feeling when you give and help which gave him a reason to be a doctor. He might think of the wrong solution yet it led him to the corner of his way to the right direction. When Patch is treating patients in his clinic with his classmates as volunteers, he shows that we are a community that can help each other.There are these services that do not only look for payments but for the happiness and benefit they will bring to other people. He heals people in a beautiful way, more in a funny way. Breaking rules is not always a bad thing. Sometimes it will let you know that there are things not to be followed to have a better result. Maybe as a do ctor, you know everything in the book but what makes you sad is that you can’t even make an old woman to eat. You may have understood everything but how about to make someone eat? And as the main point for doctors, we should not just prevent death but also to maintain life.

Epidemiology and Communicable Diseases: HIV

Epidemiology & Communicable Diseases HIV or the Human Deficiency virus is like other viruses including the flu, but the one thing that makes this virus so different than any other is that the body is unable to clear this one out completely. Once someone is infected, there is no cure. Over time, HIV can also hide or mask itself in the body's cells. The cells within a person's body that fght off infection are called CD4 cells or T cells. HIV attacks these cells and copies or replicates itself inside these cells, then destroys them.HIV over time will estroy so many of these cells that the body is unable to fght off infection anymore. When this starts happening, AIDS or Acquired Immunodeficiency Syndrome happens which is the final stage of HIV. HIV is transmitted through someone's blood or bodily fluids which can encompass semen, breast milk, vaginal fluids, and rectal mucous (AIDS. GOV, 2013) and usually it is passed from one person to another through sexual contact; however, HIV can al so be transmitted through childbirth or IV drug use. Healthcare workers are also at risk from infected bodily fluids.Fluids from an nfected person can deliver the virus to someone else's bloodstream. Within 2-4 weeks, and up to as late as 3 months, exposure to HIV can happen with a sudden onset of flu like symptoms including fever, chills, rash, night sweats, muscle aches, sore throat, fatigue, swollen lymph nodes or ulcers in the mouth (CDC, 2013). Sometimes no signs or symptoms of infection are present in someone with HIV. Certain individuals may feel sick as HIV turns into AIDS or have occasional bouts of sickness, but not really know or feel they are infected.When HIV progresses to HIV, he flu like sign and symptoms mentioned earlier can become far more severe. Many of the complications stemming from HIV are opportunistic infections, which happen in patients with a weakened immune system (CDC, 2013). â€Å"Some of these opportunistic infections include tuberculosis, salmonellos is, cytomeglaovirus, candidiasis, cryptococcal meningitis, toxoplasmosis, cryptosporiosis, Wasting Syndrome, neurological problems, and kidney disease (Mayo Clinic, 2013). Specific skin cancers including Kaposi's Sarcoma and lymphomas also happen in patients who are HIV positive† (Mayo Clinic, 2013).Antivirals are the treatment for HIV and presently there is no known cure. Treatment most often involves combinations of different drugs to avoid creating strains of the virus that are immune to single drug treatments (Mayo Clinic, 2013). The number of CD4 or T cells monitors treatment response. The viral load should be undetectable while undergoing antiviral therapy. The count is checked when treatment starts and usually monitored every 3-6 months. Even if someone has an undetectable viral load, the spreading of HIV is still a possibility.According to estimates and numbers provided by the CDC, about one and half million people 13 years of age and younger is HIV positive. Demograph ics also show that almost 20% of people who are infected do not know they have the virus. The CDC estimates that now every year, there are about 50,000 new cases diagnosed (2013). At risk groups include gay men, bisexual people, and African Americans (CDC, ) Young Atrican American males are at greatest risk tor contracting HIV among various ethnicities and races (CDC, 2013).An individual's risk for HIV or social determinants of health related to HIV is income, education, geographic region, overty, gender orientation, early childhood experiences, and alcohol or substance abuse. The CDC states, â€Å"that by reducing the number od new HIV infections and improving the health and well-being of those already infected with HIV depends on changing the social determinants that place people at risk of infection† (CDC, 2-13). The epidemiological triangle of HIV consists of three things: the person, the causative agent, or the environment (Smith, 169).The causative agent that causes AID S is HIV or the virus itself. The host is a person in the case of HIV and the environment is the either the host or the agent, but a factor that influences interaction between the two. The epidemiological triangle consists of three things: the person, the causative agent, or the environment (Smith, 169). In the triangle for HIV, the agent that causes AIDS is HIV or the virus. The host is a person in the case of HIV. The environment is neither the host nor the agent, but something that influences interaction between the two (Smith, 169).The host factors for HIV include age, sex, ethnic background, race, sexual orientation, education, and economic status (Smith, 169). The agent actors or causative agent for HIV are the virus itself and the mode of transmission, life cycle and virulence of the virus (Smith, 169). The environmental factors for HIV include social and economic considerations including family, community, political organization, public policy, regulations, institutions, wor kplace, occupation, economic status, technology, mobility, housing population density, attitudes, customs, culture, health practices, health services (Smith 169-170).A community health nurse with an emphasis on HIV/AIDS would work in a community or public health setting, educating t risk groups about safe sex practices and the dangers of sharing needles. Ideally, the nurse would connect patients to support groups and services, teach patients or people in the community about the prevention of the spreading of the disease, and help administer treatments and medications. Some important issues that nurses are bringing to the forefront in todays world include implementing strategies to keep HIV patients engaged in routine HIV medical and nursing care, incorporating prevention research findings to help reduce transmission locally and globally, carrying out outine HIV testing in health care settings, ensuring access to antiretroviral drugs, and preparing for emerging issues in HIV care suc h as diabetes, liver disease, obesity and elder care† (Kirton, 2007, p. 8). The Global Fund to fight AIDS, Tuberculosis and Malaria is a national organization that channels a portion of its funds to the international financing for he fght against HIV and AIDS. It also gives funds to strengthening health systems, as most are inadequate to educate and inform communities and people about the prevention of HIV. Programs supported by the Global Fund give to communities with lifesaving ntiviral therapies and counseling on the prevention of the virus.