Clostridium Botulinum (Microbial form and function) Essay

Clostridium Botulinum (Microbial form and function) - Essay Example Clostridium botulinum Introduction Clostridium botulinum  is a gram positive, anaerobic, spore forming rod bacillus that produces exotoxin (protein), which paralyses the nervous system (Solomon and Lilly 2001). Botulinum spores are found distributed in mud, sewage, soil, marshy sediments in coastal areas and lakes, vegetables, fruits and in intestines of fishes and animals. Under specific condition, this bacterium may also grow in foods creating neurotoxin(s). When these toxin-containing foods are consumed, it results in a medical condition clinically referred to as botulism, which often causes death. The botulinum toxin produced by the Clostridium bacteria is the most poisonous substance found in the world, where 1 gram is potent enough to kill nearly 30 billion mice (Dilbaghi and Sharma 2007: 22). This Briefing Paper will aim to: a) present a brief background on Clostridium botulinum and nature of the toxin produced by it; b) the positive and negative aspects of the toxicity, how this toxicity acts and what is the treatment; c) review the therapeutic use of toxin produced by Clostridium botulinum (Botox) Discussion Background on Clostridium botulinum Clostridium botulinum is widely present in soil, and grows best under conditions where there is low oxygen. They can produce spores, which helps them to remain dormant until favourable conditions are available that support their growth. Clostridium botulinum is â€Å"sensitive to low pH (

Analysis paper Case Study Example | Topics and Well Written Essays - 500 words

Analysis paper - Case Study Example Jane has been motivated to undertake treatment in seeking to ensure she recovers from the condition. This changes the behaviour patterns in relation to the ability for the person to meet their expectations. According to the Freud’s theory, Jane is undergoing a subconscious minds situation. She believes that the traditional medicine can be able to cure her as opposed to the medication which people. Unconscious mind includes beliefs which people hold and which come from religious elements and they are affected by the subconscious mind. These beliefs have been fundamental in shaping the belief of the patient. The patient is being held by the religious beliefs in seeking medication and believes the traditional healers have the capability to perform better than the other medication. One of the fundamental problem which is facing the care team is the process of understanding the thoughts and perceptions of the patient. The diagnostic approaches have been made difficult by the mixed reactions of the patient as a result of religious beliefs. Various therapeutic communication techniques can be utilised in undertaking the treatment of the patient and these will be critical to overcoming the difficulties being experienced in presenting a working intervention to the patient (Dossey & Keegan, 2012). These communications therapies have a significant effect in ensuring that the patient is capable of accepting the medical interventions which will be applied by the medial team. The following approaches would be suggested for Jane Using silence – Jane normally drinks with friends and does not appear to have any issues in relation to that fact. The use of silence by the professional medical teams can enable her to provide information voluntarily which will be able to assist the medical teams to understand her behaviour. Encouraging description of

PromptDescribe your intellectual interests, their evolution, and what Essay

PromptDescribe your intellectual interests, their evolution, and what makes them exciting to you. Tell us how you will utilize the academic programs in the Col - Essay Example The phones, watches and stereos were all under my mercy. I could not get over my mesmerizing into the intricate connection of this device to that and the overall effect. Needless to say the string that followed such activity was endless circling around what is this, how and why. This was my favorite hobby. I suppose this kind of behavior is normal for kids and especially those that are destined to make great discoveries in future. It all starts with a question like why is the sky blue Of course our reaction to the response varies thereby demarcating each child's individuality and uniqueness. In my case the answer to this question was a start to what have become a resilient pursuit of greater knowledge and more answers to natural phenomenon. High school was an eye opener for me after the exposure to the topics on atoms and molecules. It is fascinating to know that here are millions of invisible elements in the atmosphere that cause such real effects in the daily life. (Schmelcher & Schweizer, 15) Physics and astronomy intrigued me and I kept myself enlightened with books such as black holes and time wraps by Kip S. Thome. My relentless questions soon became equally sophisticated to why dark matter exists. There was no turn around for me at this point.

Adult education self reflection Essay Example | Topics and Well Written Essays - 1500 words

Adult education self reflection - Essay Example These include the social, economical, and political social settings. The dispensers of knowledge are the people who we refer to as the teachers. Teachers are responsible for providing direction and highlighting the requisite elements of learning a concept. Therefore, teachers play a central role in the process of learning. The most stressed form of teaching is the child education characterizing the social and economic structures of most societies. However, learning continues into adulthood. Therefore, since teaching is a practice that can be administered to every member of the society, the learners can be categorized into two broad groups, which are the young learners and the adult learners. Recognition of these two distinct groups of learners brings us to the juncture of understanding the context of adult teaching and learning (Griff, 2008 p.120). Introduction Adult learning is a phrase describing the type of learning administered to adult members of the society. The adult learning settings could include places like institutions of higher learning, work places, and any other setting where administration of knowledge is happening. As it is understood from the basic principles that the purpose of administering knowledge is to instill some principles concerning a social, political, or economic concept into the learner, it can be understood that learning has to be carried in a systematic manner that will facilitate optimum understanding of an underlying concept by the learner. It is undeniable that adult learners require different tools and techniques in order to learn, compared to their young counterparts (Pete & Alisa, 2010 p.48). Therefore, adult teachers are expected to acknowledge this fact and develop suitable mechanisms and techniques of achieving the objectives of adult learning efficiently. During their trainings as adult teachers, these individuals will be expected to master the principles guiding adult learning. Once in the field, these teachers are exp ected to articulate the knowledge into their expertise. To check the application of these ideal principles in their duties, the adult teachers evaluate themselves by the use of self-reflective inventories. Now, it will be logical to postulate that the process of effectively dispensing knowledge to adults has to follow some formulated set of standards, which must be adhered to by the teachers in order to achieve the objectives of the exercise. Self-Assessment inventory is a tool used to evaluate or gauge someone’s adherence to some guiding or ideal principles in the course of duty. In this context, self-assessment inventories are formulated questionnaire papers used by adult teachers to gauge their professionals in their teaching duty. Since a teacher who sticks to the practice of ideal teaching principles can only attain optimal adult teaching, it is advisable for every tutor to ensure close inclination of these principles as much as possible. Therefore, teachers use the inve ntories to evaluate their position in reference to the standard teaching requirements. These inventories are usually made of open or wide range close-ended questionnaires. During evaluation exercises, a teacher is supposed to respond to the open-ended questions as honestly as possible. Upon completion of responds, the teacher will evaluate his/her position by comparing the questionnaires responses with the expected standards of teaching. Self-evaluation will unearth the teacher’s weaknesses and strengths in his/her duty. Having acquired the knowledge concerning strengths and weaknesses, a teacher will react by developing control mechanism that will ensure professional performance

Toyota Recall Essay Example for Free

Toyota Recall Essay They have concluded that a precision-cut steel reinforcement bar (Consumer FAQ, 2010) needs to be installed on the pedal for it to eliminate any unnecessary friction that is causing the pedals to stick. Toyota is ensuring that the installation of the steel reinforcement bar is a permanent fix and will eliminate the tension between the two surfaces and the pedals will no longer stick. Toyota has also done the following to reach their customers and take care of the recall issue: 1 . They have mailed letters to all owners of vehicles involved in the recall. The letter contains specific instructions on what to do to get their vehicles fixed. 2. Many Toyota dealerships have extended their service hours in order to meet the needs of the consumers. 3. Within those dealerships they are working to improve customer relations by expediting repairs, offering free car washes, oil changes and follow up maintenance service. 4. In order to support its dealerships Toyota has provided financial help to cover any additional costs related to the recalls. All with the end consumer in mind. They want their customers to be able to resolve the issue as quickly and conveniently as possible. 5. Toyota has put together informational videos, campaigns and press releases describing the problem and advising their customers of the risks associated with the recall and advising them of quick a solution. 6. They are working closely with CTS on future manufacturing processes to avoid any additional problems. Overall, yes I think Toyota is handling the problem to the best of their ability and ssues and are guaranteeing that their simple fix to their poor design is a permanent fix. They are working with CTS to improve the design and future manufacturing practices for their parts. They are supporting their dealerships, doing what they can to keep the customers involved and informed of new findings. They are putting their customers first. I do think their efforts are limited; they can only fix so many cars at a time, I believe Toyota will be more selective on who they choose to manufacture their parts from now on. Like the old saying says you live you learn Toyota was focused n becoming the number one automaker in the world and once it obtained the title it may have forgotten why they became the number one automaker in the world, which was quality. In my opinion they are handling the problem with class and integrity. Once you fall all you can do is get up and keep walking and that is exactly what Toyota is doing. This recall only affected 8 of their Toyota models, not any others or other lines such as their Lexus brand or their scion.

Fear of Crime Survey Results

Fear of Crime Survey Results Data The data set used and analysed consisted of results from residents (N=300) who participated in the 2014, Gold Coast Community Survey on fear of crime and the factors that are associated with individual perceptions of what contributes to their fear. The data gathered from the survey analyses groups of categorical variables including fear, demographic characteristics, news and information, as well as community characteristics. Fear and News and information are categorised into their own variables with multiple values, whereas demographic and community characteristics are grouped represented by individual variables and further represented through multiple values. Demographic characteristics include; gender, age, income and education level. Community characteristics include; collective efficiency and Social cohesion. A detailed description of the data set including values is shown in Table 1. In this analysis the primary focus is to determine the association between fear and various othe r factors, thus determining that fear is the categorical dependant variable and the subsequent variables are independent variables. Table 1 Sub-sample size and Frequencies of variables. (N ­=300) Methods To determine whether there was a connection between fear of crime and various factors that could possibly influence or are associated with each individual’s perceptions, a chi-square r x c test for independence was conducted on the assembled data. This test was chosen to be conducted for this analysis due to all the variables being used are categorical with multiple values. Therefore meeting two assumptions for the chi-square test for independence; all categorical variables (Nominal or Ordinal) and should consist of two or more categorical variables. The other primary assumption of the chi-test for independence, which is the expected frequency should not drop below five in more than 25% of the cells in a contingency table was also met. The results displayed only two (4.55%) cells falling below the expected frequency count of five, with the minimum being 2.08, therefore not contributing to more than 25% cells of the contingency tables. Results A chi-square r x c test for independence was performed to examine the relationship or association between fear of crime and various factors that contributed to each participants perceptions. Within this analysis there were multiple variables to be examined to determine the association with fear of crime, the significant findings will be discussed prior to results table 2. Within the age of participant variable, 48% of participants over the age of 65 were fearful of crime, compared to 2.3% of participants aged between 55 and 64, 4.7% of participants between the ages of 25 and 54 years, and 3.3% of participants aged between 15 and 24 years. The relation between the dependant variable fearful / not fearful and the variable age of participant, showed that there was a significant association (X ² (3, N=300) = 106.59, p ≠¤ .001). The Cramer’s V was 0.59, thus resulting in approximately 35% variance of frequencies of fear can be explained by the variance of age. Within the var iable news and information, 46.7% of participants perceived the television increased fear of crime compared to 3.3% due to the radio, 7.0% due to print, 1.3% due to the internet and 0% due to other sources. The relation between the dependant variable and the variable of news and information, showed that there was also a significant association (X ² (4, N=300) = 59.39, p ≠¤ .001). The Cramer’s V was .445, thus resulting in approximately 20% variance of frequencies of fear can be explained by the variable of news and information. Both the Age variable and the news and information variable showed statistically higher associations with fear of crime, representing factors from demographic characteristics and news and information; compared to alternate variables, particularly community characteristics. Further detailed results of variables shown in table 2. Table 2 Results of chi-square test on variables associated with fear on crime Conclusion The variables age and news and information both have a significant association with the fear of crime within the Gold coast community. Addressing the research questions, the preceding data demonstrates that demographic characteristics and news and information both are related to residents fear of crime thus, concluding that the answers to research question one and two are, true, there is a relation The third research question enquiring the relationship between community characteristics and residents fear of crime, although the data concluded there is a slight relationship, it is not as significant as the other variables. Therefore it is suggested that strategies address the residents fear on crime by focusing on the factor of age and the production of news and information of crime, to alter the perceptions.

Media Streaming Techniques

Media Streaming Techniques Chapter 7 : Media Streaming and Storage In this chapter, we learn about media streaming techniques and typical devices used within streaming. Streaming is the process of media delivery via computer networks, most notably the internet. Learning Outcomes To explain streaming and how media is transmitted via computer networks To give an outline of the encoding and storage of video material. Media Streaming is the process of transmitting audio and video signals via computer networks, most notably the internet. It requires three parts, a source (to encode the stream), a server (to host the streaming service), and a browser or player (to view the stream). Streaming is an increasingly important technology to learn about as content continues to be delivered to a variety of internet connected devices. Internet Protocol Television (IPTV) is effectively streaming programmes (both TV and radio) and movies over the internet instead of terrestrial broadcast. The media streamed may be live (e.g. news) or on-demand (e.g. movies, programmes etc.). IPTV is usually over a ‘closed’ or ‘subscriber’ network e.g. VirginTV (UK) with a specified minimum Quality of Service. This should not be confused with Internet TV (a.k.a. Web TV) which is transmitted using the same protocols but primarily consumed via a web-browser on the ‘open’ internet (eg. BBC iPlayer). 7.1 Stream Creation 7.1.1 Capture The media stream can be pre-recorded or a live feed that is ‘captured’ and run through an encoder. An audio live feed can be used for internet radio; it requires a sound card to capture the audio input. Sound capture devices can be internal (eg sound cards or integral computer motherboard device) or external devices (e.g. audio interface) though it would be wise to review the earlier chapter on professional versus domestic signal levels before assuming that a built-in motherboard can handle your incoming audio signal. Similarly, live video is via a camera (webcam – poor quality, or video camera – higher quality) but the capture device is typically by video capture cards, IEEE 1394 connection (aka Firewire) or for domestic quality, a USB device. Some USB plug-in devices carry both audio and video signals; it is the software in the encoder that is set to look for where the feeds are attached to the computer. Current tablet and smart-phones can be used as internet streaming devices. These, along with some cameras, are already ‘cloud connected’ for storage and sharing while IP-Cameras (viewable and controllable on streaming sites) can be used for home security etc. It is possible that these will become more ubiquitous and have greater streaming functionality in the future. 7.1.2 Encoding Encoding is performed by an encoding software package such as Adobe Flash Live Media Encoder. A ‘live’ feed or pre-recorded media must be compressed and fed into the stream at a suitable bit rate and in a format with which the media server can cope for the purposes of ingest and re-direction. It is necessary for any audio video compression process to have the right decompressor at the play-out destination. Compression (bit-rate reduction) at the transmission end can be in either one or two pass encoding and at a constant bit rate (CBR) or variable bit rate (VBR). Live encoding must be done in real-time ‘on-the-fly’ so it is a one pass encoding i.e. the image data is analysed and compressed once. Pre-recorded data can be a multi-pass (usually two-pass) process so the quality of the encoding is higher, but is not used in live stream encoding. Constant bit rate (CBR) is used for media streaming as the encoding quality and feed to the server remains at the same bit rate, so can be at the maximum level the process will allow. Variable bit rate (VBR) is controlled by the bit rate range (Minimum – Maximum) or the average bit rate (each pass is averaged, and then several averages are re-averaged) to achieve a close to uniform bit rate for the stream. Variable bit rate is used for a multi-pass encoding process. 7.2 Network Connectivity 7.2.1 IP address (Internet Protocol Address) Every computer device that can be connected to the internet requires a unique address so that it can be found, rather like a telephone number. So to host a media stream that can be found on the internet, the media server requires a static IP address. Like telephone numbers in a directory, IP addresses are convertible to meaningful names by a Domain Name Server (DNS) process running on a web-hosting server. Consequently media servers and web-servers are closely coupled, and media is capable of being found using a web-based URL (Uniform Resource Locator) such as www.youtube.com. The source device (the computer or IP enabled camera etc.) needs to be found by the media server. This means the device has to ‘join’ the media server’s network (a more permanent connection) or pass on its IP address for the session (a temporary connection lasting until the session ends). Network Router The link between the source device and the media server may not be a direct connection, but may run through other connecting devices (network servers and routers). A router is a device that redirects data to another connected device either on its own or another network. This is basically how the interconnectivity of the internet works, routing between the server acting as the source device’s internet service provider to other networks and finally being re-directed to the destination. Multiplexer (MUX) Obviously it would be inefficient if the stream of data being passed to a media server is solely dedicated to one source device. This is a poor use of bandwidth, (bandwidth being the range of frequencies available in the data stream), so multiple devices are streamed simultaneously. A multiplexer (MUX) is a device that is used to combine input streams into a single output stream which is then split back into individual streams using a de-multiplexer (DEMUX). Figure 7-1 : Multiplexer to Demultiplexer 7.2.2 Web-Host Servers For a stream to be found it must be made available to web-browsers or stand-alone players (e.g. Windows Media Centre). The web-host server handles the web-site connectivity but need not be the same computer as the media server but both need a connection between them that isn’t prone to interruption. This web site often has a web page (HTML –HyperText Markup Language) with a plug-in media player connected to the media stream being managed by the media server, and contains the web-site in which the page resides. Consequently it must link to the internet and Domain Name Server process to resolve the IP Address from the web-site name, so the routing can direct the end user’s browser to the host. Figure 7-2 : Connection diagram The browser only needs to connect to the internet via its Internet Service provider to link to the media stream’s web-host server (see figure 7-2 Connection diagram). Hence any internet device with media playing capability could view the stream including smart-phones, tablets and PCs providing it has the right decompressing codec and can manage the bit rate of the stream from the media server. This is why it is important to offer various streams of differing quality, bit rate and formats (e.g. a Windows Media Video .WMV format file may not play on an iPad without a conversion app). A further file often created at the time of the stream hosting web page is an announcement file. These are particularly important to make potential viewers aware of the content and set links to the media stream. Podcast and Vodcast Podcasts are audio files that are available for download from a web hosting service (vodcasts are video inclusive podcasts) and differ from media steaming in so much as the content is downloaded then played on the user’s device. Streamed media is viewable but not downloaded to the device. They are often announced by RSS feeds (a short web content file) to which your device has been connected. 7.3 Media Streaming Servers A Media server is additional software that runs on a typical web server (or file server with web-host server connection). It requires a static IP – so its address does not alter on each session). The media server software needs to add additional protocols to those found on a simple web-server. In addition to Hypertext Transfer Protocol (HTTP) which is inbuilt with the web server, these additional protocols differ for proprietary server software. Real Time Messaging Protocol (RTMP) is for Adobe Flash systems along with HTTP Dynamic Streaming (HDS). Microsoft Media Services (MMS) is no longer supported for windows streaming and now uses HTTP and Real time Steaming Protocol (RTSP), and finally there is an HTTP Live Streaming (HLS) protocol which is for Apple iOS based systems. Adaptive streaming (HDS, HLS and Microsoft Smooth Streaming) requires the stream to be fragmented (which is how HTTP delivers content) and may utilise the MPEG-DASH codec. Adaptive streaming is where the content is streamed as fragments in a variety of bit rates with the computer automatically selecting the next most appropriate sized fragment based on its current playback state to minimise buffering. This differs from the older method of providing different dedicated streams at constant bit rates and the client selecting one most appropriate to their computers (or routers) connection capability. 7.3.1Content Delivery Unicast In a Unicast scenario the client connects to the server on a one-to-one basis. The number of clients is limited by bandwidth considerations. Multicast In a multicast scenario the server streams to a multicast IP address (this is a special address on the client’s network). This is a one-to-many basis and is an effective means of reaching many clients with less bandwidth overhead. UDP v TCP All content (including streams) is delivered across a network in packets. In User Datagram Protocol(UDP) the stream is sent without checking the connection and no acknowledgement of receipt is made. UDP is seen as unreliable but it is simpler and quicker. Transmission Control Protocol (TCP) is bi-directional so will check for receipt and retransmit missing packets. TCP is seen as reliable but slower. A good discussion on this is at http://en.wikipedia.org/wiki/User_Datagram_Protocol#Comparison_of_UDP_and_TCP 7.3.2Live Streaming A live stream needs to be seen at the time of broadcast. A live stream needs connection to a publishing point on the media server which connects to an encoding device. This may be another computer or a camera with IP addressable capability. The publishing point provides the connection between the content (live stream or pre-recorded) and the client’s computer which links to it via a web-host request from the internet. 7.3.3 Video on Demand (VoD) If the stream is recorded then it is treatable in the same way as any pre-recorded media file. Note:, it is not advisable to record an encoded stream and then re-encode it as this would severely compromise its quality. Streams and Playlists Media streaming servers can have many pre-recorded files ready for streaming, often collected into separate playlists (one media file plays immediately after another). These playlist or file streams can be on a continuous loop, or awaiting selection by a viewer through the browser. This latter selection method is called video–on-demand, although it equally applies to audio files as well. Bandwidth considerations A media server can manage several streams and be linked to several web-hosts at the same time. This requires careful planning of the number of streams the media server can handle which is a function of its bandwidth connection. The more simultaneous streams being handled then the less the size of the bit rate is available for each of those streams. If a media server has a 1Gbit/second connection then it could only handle 1000 x 1Mbit/second streams. However, full utilization of the bandwidth like this is not normally done; there are recommended bit rates for video streams based on destination image size and aspect ratio, e.g. a 1280* 720 HD video with stereo audio will require around a 2.5 Mbit/sec rate. A good source for this is: http://www.adobe.com/devnet/adobe-media-server/articles/dynstream_live/popup.html Push Pull The relationship between the encoding source device and the media server is based on which device initiates the stream. i.e. it is PULLED from the source device by the media server (needed for video-on-demand), or it is PUSHED to the server by the source device to start the service (a broadcast need). The media server needs to know how the stream is to be initiated for it to start the service. 7.4 Storage 7.4.1 Read Write speed All devices that are used to store data (including audio and video) need to be able to write to the storage device faster than the transmitted data is fed to it, otherwise it must buffer (temporary memory store on a faster device) and then read from the buffer to maintain the data transmission sequence. Consequently if a device is used that cannot cope with the data transmission rate than it will fail or lose data e.g. using a low class SD card in a camcorder. Data is written to storage devices and stored in a binary format but unlike data transmission the Kilo/Mega/Giga/Terra sizes are based on multiples of 1024 (210) not 1000. The speed of data being read from a storage device may be slower than required to play in real-time which would result in its being prone to stutter and freeze. 7.4.2 Simple Storage Devices Considerations Tapes – early tapes (DVCAM, DV) required striping. This was to put a continuous time code on the tape before recording – however later tape devices (including mini-DV camcorders) made this unnecessary, though any discontinuities or repetitions in the timecode could cause problems when ingesting material to an editing workstation. Cards – cards such as SDHC have a class rating which will denote the read/write speed of the card in Megabits per second, and storage size in Gigabytes. Always check to ensure the card will work with the device and check to see if there is a device firmware update, particularly if the device is more than a year old. USB sticks as with cards their read write speeds differ wildly – check using an on-line speed testing application, it is usually better to transfer video files to a hard disk before using the file for playback or editing. CD and DVD disks have a read/write speed depending on the quality of the disk (recording speed), but another consideration is the data rate used in the writing process from such software as the video non-linear editor (NLE). An ‘average’ bit rate (based on Peak and minimum Variable bit rate (VBR)) or ‘constant’ bit rate (CBR) needs to be selected, that will not only write to the disk but allow the disk to be played on the output device. Computers can write to disks comfortably at 9 – 11 Megabits per sec. But this needs to be slower (around 5 Mb per sec) if writing to a DVD that is to be played on an older standard-definition DVD player. You should consider the bit rate as part of your consideration of overall file size and the storage capacity on the disk. A good explanation of data rate calculation is given in:-https://helpx.adobe.com/encore/using/project-planning.html#bit_budgeting Hard Disks – Many older hard disks (often found in laptops) spin at 5400 rpm, this is too slow for video playback and a minimum 7200 rpm disk is needed. Hard disk read write at around 50-150 Mbytes per sec. SSD Solid State Disks are now finding favour due to faster read/write speeds than traditional hard disk technology. SSD read write speed is between 200-500 Megabytes per sec. 7.4.3 Network Storage Connection speed Any network storage has to pass data via the network card (NIC network Interface Controller), this needs to be as fast as possible (preferably a fibre connection of 1Gbits per sec but a minimum of 10 Mbs for Ethernet). Unlike other storage considerations network traffic can be bandwidth throttled (i.e. the bit rate is reduced) and will affect speed. If the NIC card is under your administration always set it on maximum performance. NAS, SAN, Cloud NAS (Network Attached Storage) is what most people think of as network storage- an array of hard disks that allows for file storage remotely from your computer directly accessible via the network. SAN (Storage Area Networks) are a separate network but pretty much do the same job as NAS differing in access protocol. The Cloud is just another remote storage area (uses SAN technology) but accessed via the internet (typified by a URL connection – Uniform Resource Locator) not a local area network LAN connection (typified by a UNC connection – Universal Naming Convention). 7.4.4 Raid RAID (Redundant Array of Independent (or inexpensive) Disks) allows the disk storage to have a measure of redundancy and/or striping to create a secure method of retrieving data should there be a disk failure. For media technology only a few RAID levels (configurations) are used (i.e. Levels 0 and 5 – see figure 7-3 Raid diagram). Level 0 – usually this requires at least two disks and the data is striped across them. (Note: It can be put on one physical disk using two logical drives – but with little advantage). That essentially means data is split into blocks and distributed across the disks. Typically used in video storage applications as it is fast, there is no redundancy (no duplication) so recovery from a disk crash is almost impossible. Consequently if a disk fails then the file may not be fully recoverable. If you have RAID 0 on your disks, always be sure to keep an external copy of your original audio or video files. Level 1 – disk mirroring, requires at least 2 disks but is slow as it writes the same data twice (once to each disk). Data is easy to recover as the system has full redundancy (disk duplicated). This level is good for general data and possibly audio only files. Many video editors feel this level is too slow for working with video files. Level 5 – block striping and parity. This requires 3 disks minimum, data is striped across all the disks (except one) and the block parity is put on the excepted disk. This is done repeatedly using a different disk for parity on each block. One disk can fail and be rebuilt from the others by using the parity blocks on remaining disks. Raid 5 is also popular with video editors as long as the raid controller is fast enough. It is slower than level 0 but faster than Level 1 and has enough redundancy for disk recovery.