Bivalves, the Twin-Shelled Mollusks

Bivalves, the Twin-Shelled Mollusks Bivalves are a group of mollusks that includes clams, scallops, oysters, mussels, razor shells, cockles, venus shells, borers, trough shells and many others (some of which live in the deep sea and have yet to be identified). Bivalves are the second most diverse group of mollusks, ranking only behind  gastropods in number of species. Bivalves are so named for their paired shells. The shells of a bivalve consists of  two halves, mirror images of one another, that are joined at one edge by a flexible hinge. Each half is asymmetrical and rounded, so that when its closed against its opposite number, this forms a domed space near the hinged edge of the shell that accommodates the bulk of the bivalves body and narrows towards the edge of the shell that opens. (Bear in mind that although most bivalves have paired shells, a few species either have drastically reduced shells or no shells at all.) Bivalves live in marine and freshwater habitats; the most diverse, consisting of 80 percent of all species, live in ocean habitats. These invertebrates have four different lifestyles: epifaunal, infaunal, boring and free-moving. Epifaunal bivalves attach themselves to hard surfaces and remain in the same spot for their entire lives. Epifaunal bivalves, such as oysters, adhere to surfaces using either cementation or byssal threads (sticky chitinous threads secreted by a gland in the foot). Infaunal bivalves bury themselves in sand or sediment on the seafloor or in riverbeds; they have thin, soft shells armed with hard tips, and they bore into solid surfaces such as wood or rock. Free-moving bivalves, such as scallops, use their muscular single feet to dig into sand and soft sediments; they can also move through the water by opening and closing their valves. Most bivalves have a pair of large gills  located in their mantle cavity. These gills enable the bivalves both to extract oxygen from the water (in order to breathe) and to capture food; water rich in oxygen and microorganisms is drawn into the mantle cavity and washes through the gills. In species that burrow, a long siphon extends to the surface to take in water; mucus on the gills helps capture food and cilia transfer the food particles to the mouth.    Bivalves have mouths, hearts, intestine, gills, stomachs and siphons, but do not have heads, radulae or jaws. These mollusks possess abductor muscles that, when contracted, hold the two halves of their shells closed. Bivalves are also equipped with a muscular foot, which in many species, such as clams, is used to anchor their bodies to the substrate or to dig down into the sand. The bivalve fossils  date back to the Early Cambrian period.  During the ensuing Ordovician, bivalves diversified in terms of both number of species and the variety of ecological niches occupied. Species Diversity Approximately 9,200 species Classification Bivalves are classified within the following taxonomic hierarchy: Animals Invertebrates Mollusks Bivalves Bivalves are divided into the following taxonomic groups: ProtobranchiaPteriomorpha - This group includes animals such as scallops, oysters, pearl oysters, mussels, arcs and various other familiesAnomalodesmataRostroconchiaHeterodontaPalaeoheterodonta Edited on February 10, 2017 by Bob Strauss

How to Make a Family Photo Calendar From Scratch

How to Make a Family Photo Calendar From Scratch Looking for a personalized gift that will be enjoyed year-round? Its easy to create your own personalized photo calendar. Include images of friends, family, ancestors, or special places on your calendar to remind you of special people or events. Make your own calendar for grandma of the grandkids, or one of yourself for the special person in your life. Photo calendars are a thoughtful, inexpensive gift that can be used every day of the year. Select Your Pictures Find pictures from your collection that suit your fancy, and use your scanner to make them digital. If you dont own a scanner, then your local photo shop can scan the pictures and place them on a CD/flash drive for you or upload them to an online service. Dont be afraid to get creative and branch out from traditional photographs - scanned copies of a childs artwork or family mementoes (letters, medals, etc.) also make nice calendar photos. Prepare Your Photos Once you have your photos in digital format, use photo-editing software to add captions, or rotate, resize, crop, or enhance the pictures to best fit your calendar. Create the Calendar ​If youd like to create and print a photo calendar yourself, specialized calendar software programs make a printable calendar as easy as drag-and-drop. You may also already have software right on your computer which will do the job. Many word-processing programs, such as Microsoft Word, include basic calendar templates, as do many photo-editing programs. A number of free downloadable calendar templates can also be found online. As an alternative, there are many calendar printing services and copy shops which can create a personalized photo calendar for you using your photos and special dates. Some of the most popular and versatile include: ShutterflyMixbookPicabooSnapfish Personalize Your Calendar Once you create your calendar pages, its time to customize. Go beyond the basic calendar by adding your own custom colors and fonts. Unlike bland, mass-produced calendars, each month can have a different theme. Match photos to the months theme- a photo of your parents on the month of their wedding anniversary, or a closeup of the family Christmas tree and its treasured ornaments for the month of December.Add personal dates, including birthdays, anniversaries, holidays, and other significant events. Not sure when Thanksgiving or Mothers Day falls this year? Check out holiday calendars for a wide range of national and holiday dates.Keep family history alive by including photos of your ancestors and major events from your familys past. You may be surprised to find how many of your family members share birth dates with their ancestors. Print Your Calendar Once youve finished designing your photo calendar, its time to print. If you plan to print the calendar yourself at home, begin by printing the photo pages- one for each month- preferably on good quality photo paper. Once completed, youll need to reload the printed photo pages into your printer in order to print the monthly grids on the other side of the pages. Remember that each months picture appears on the opposite side of the previous month; for example, you should print Februarys monthly grid on the back of Marchs photo. Make sure that you understand which side and end of the paper your printer begins to print from, to avoid mistakes with page orientation. If youre using a special calendar software program, look for specific directions and tips for printing your calendar. Alternatively, many copy shops can print and assemble your finished photo calendar for you from your saved copy on disk. Be sure to check with them before starting to see what file formats they accept. Add Finishing Touches After youve printed and double-checked your finished calendar pages, you may want to take them to your local copy center to have them spiral-bound for a more professional look. Alternatively, use a paper punch and bind the pages with brads, ribbon, raffia, or other connectors. Enjoy your custom family calendar. And make sure youre prepared to repeat the project next year, because people will definitely ask!

Long term oxygen therapy in patients with chronic obstructive Essay

Long term oxygen therapy in patients with chronic obstructive pulmonary disease - Essay Example A prescription of LTOT is properly considered, because Medicare claims on LTOT prescription only if this therapy is vitally important for patient’s life. In case of such kind of strict regulations it is weird that LTOT is blamed for causing deaths or worsening patient’s quality of life or health status. Generally speaking, LTOT is a generally accepted and approved treatment for patients with COPD. With regard to the fact that there are different points of view expressed by medicals, critics and researchers concerning LTOT, this research is focused on unprejudiced consideration of this method and discusses both its benefits and negative outcomes. On the one hand, the results of the studies, which have been constantly conducted, witness that LTOT prolongs patient’s life. On the other hand, a poor diagnosis and inexact guidance for this treatment prescription and deaths of some patients prove inconsistency an inappropriateness of LTOT for individuals with COPD: In COPD patients considered for LTOT, the FEV1 should normally be less than 1.5 IV litres, or less than 40% of predicted normal values. The presence of arterial hypoxaemia with a higher FEV1 suggests that there may be another cause for the hypoxaemia, e.g. sleep apnoea, and further investigations will be required. Patients should be prescribed LTOT for at least 15 h per day, although survival improves when LTOT is used for more than 20 h per day. Thus the hours of LTOT use should not be restricted, especially in severe COPD. There is no benefit in the use of LTOT in COPD patients with a PaO2 above 8 kPa (Tiep, Barnett, Schiffman, 2002). Benefits of LTOT may be proven by improvement in patients’ lives, quality of patients’ lives, decrease of mortality levels, psychological and cognitive statuses’ perfection etc. In this frame of discussion, it is relevant to mention a study on relationship between heath and quality of life before and after LTOT. The results show that quality of life among

The Law of Comparative Advantage Essay Example | Topics and Well Written Essays - 2000 words

The Law of Comparative Advantage - Essay Example Because the theory failed to understand the laws of absolute and comparative advantage, which advocates that trade, may not necessarily be a zero-sum game, mercantilists regulations were gradually removed in Britain in the course of eighteenth century after the government has fully embraced Adam Smith's concept of laissez faire (Wikimedia Foundations, Inc). The greatest challenge to mercantilism was Adam Smith's theory of absolute advantage. It is said that Smith's publication of the book The Wealth of Nation in 1776 has ended the rule of mercantilism as an economic philosophy. In contrast to the necessity of government control in the mercantilists' philosophy, Adam Smith advocated the laissez faire system, with limited government intervention in the economy. Particularly, Smith believe that trade would be beneficial to both countries through specialization. In practical terms, when one country is more efficient than another country in the production of one commodity but is less efficient in the production of another, then both can gain by specializing in the commodity in which it has the absolute advantage. ... As trade is deemed beneficial to all, restrictions are discouraged and limited government intervention is advised. An Unchallenged Theory An enhancement and definitely a higher notch than the theory of absolute advantage is the law that says that one country can benefit from trade even if it is less efficient in the production of both commodities. It is the law of comparative advantage: an impetus for small nations to actively participate in trade as it is believed to benefit both the big and the small countries. Introduced by David Ricardo in 1817 through his book On the Principles of Political Economy and Taxation, comparative advantage posits that trade can create value for both countries even if one has the fewer resources in the production of all goods. Using the production possibilities frontier, Ricardo was able to prove this, achieving a significant breakthrough in the field of international economics. Practically, Ricardo believes that given the situation, both countries can still gain by having the less efficient country specialize in the production and exportation of the commodity in which its absolute disadvantage is smallest and import the product in which it has its greatest absolute disadvantage. The commodity in which one country has the least absolute disadvantage can be thought of as one in which it has the comparative advantage. The gains are realized as both countries specialize in the production of commodity in which it has the least opportunity cost (Mankiw). The Gains from Trade: A Simple Numerical Example To facilitate understanding of the gains from trade, we cite the example from the Principles of Macroeconomics book of N. Gregory Mankiw. Given that it takes 20 hours for farmer to produce 1 lb of meat and 10 hours to produce 1

Education Dialog Essay Example for Free

Education Dialog Essay What does it mean to be an educated person? There is no simple, out-right, correct answer to this question. Everyone will have a slightly, if not very, different answer. â€Å"†¦ ‘What does it mean to be a liberally educated person?’—is misleading, deeply so, because it suggests that one can somehow take a group of courses, or accumulate a certain number of credits, or undergo an obligatory set of learning experiences, and emerge liberally educated at the end of the process. Nothing could be further from the truth†¦Ã¢â‚¬  (William Cronon 5) To me an education is about grasping not specific facts, but concepts as a whole, to gain knowledge of things that can be applied to not just the status quo but things in the future as well. To be properly educated one must keep an open mind, be able to take all the sides of an argument into account and be able to see where they are coming from. To be educated,, is to be free of ignorance, to not let our own emotions and experiences corrupt our view, to be able to think for yourself and think critically at that, but also to comprehend what is being said to you, or what you are reading and understand that your learning will never end. No matter the amount of knowledge you have on a certain topic there will always be more to learn, either on that topic or other topics and an educated person knows that, so they are always striving to learn more. Critical thinking is a huge part of being considered educated. You don’t just listen to hear someone talk, and you don’t read to just see letters form words on a page, you do these things so you can derive meaning from the words written in a book and the words coming from a person’s mouth. How does one measure intelligence? How would you know where you stand compared to others? This is where things get a little tricky. From my own experience in the public education system we were given facts, dates, places and names to be memorized for tests. How much you could memorize directly translated to what grade you would get on a test. Students would cram right before an exam, and their minds would only retain that knowledge for a couple days at most. In my English class my teacher spent the whole year preparing us for one test at the end of the year, one test. We were actually given the test three times before the â€Å"final exam†. You were given the correct answers and all you had to do was memorize it, if you could memorize the answers you would get an A grade. I don’t get how standardized tests are used to measure intelligence since there isn’t a standardized person. I believe standardized tests should be made with essay topics to give students a chan ce to explain their thinking, their â€Å"why’s† I can understand why certain subjects become important when trying to shape a well rounded educated person, such as: math, history, writing and composition. History would be about the only subject in which there could be too much focus on dates and facts, to where they begin to dismiss the â€Å"Why did they do that?† because they’re focusing on the fact that they did do it. We are taught history so we can do our best to prevent repeating it, the facts won’t really help all too much in that, but the critical thinking will. We need to be aware of what’s going on around us, notice when things are beginning to stir. We all must be educated to advance in our world, to learn from our mistakes, to make new mistakes and set forth a course to the ideal of a perfect world or to achieve a perfect education.

Ancient Egypt Essay -- Egyptian History Essays

Ancient Egypt Ancient Egypt is located along the Nile River of Northeastern Africa. More specifically, it is the territory where ancients Egyptians lived in the valley of the delta and the Nile. It was a thriving civilization for more than 3,000 years, from about the time of 3300 BC to 30BC. The culture of Ancient Egypt is identified and very well known for many aspects of their ways of life. Considering the time period, they were very technologically advanced. This can especially be seen through the great pyramids and hieroglyphs that elaborately decorate the walls of them. Pyramids were not small structures. In fact the largest one was over fifty stories high. In addition they were also built completely by manual labor. Labor consisted of moving limestone blocks that weighed on average 2.5 metric tons and could weigh up to 15 metric tons. In addition they had to form these blocks, move them, and sculpt them into the great structures known as the Pyramids. As you can imagine they took several decades of day in and day out work to complete these massive structures. The hieroglyphs were also an important part of not only the Ancient Egyptian culture but the pyramids especially. They provided pictorial descriptions for burial chambers, temples, jewelry, and important statu es. Ways to decipher them were unknown until the discovery of what is known as the Rosetta Stone. It was a stone that showed the same text in three different languages. Then early in the 19th century a French scholar name Jean Francois Champollion was able to decipher it and later on aid in learning the language of the dead language of hieroglyphs. Hieroglyphs are still being deciphered to this day. Ancient Egypt was able to prosper for such a long perio... ... November 2003 from http://www.greatscott.com/hiero. Iversen, Erik. The Myth of Egypt and Its Hierolyphs In European Tradition. Princeton, New Jersey: Princeton Univeristy Press, 1993. Minnesota State University. "Hieroglyphs." Retrieved 21 November 2003 from http://www.mnsu.edu/emuseum/prehistory/egypt/hieroglyphics/heiroglyphics.html. Park, Rosalind.The Scientific Invention of Hieroglyphs or Hurrah for Pliny! Great Britain: Azoth Publications, 1997. Silverman, David P. Language and Writing in Ancient Egypt. Pittsburgh,Pennsylvania: The Carnegie Museum of Natural History, 1990. "The Pyramids of Ancient Egypt." Intercity Oz Inc. 1999. Retrieved 15 November 2003 from http://www.touregypt.net/featurestories/pyramids.htm. Winston, Alan. The Pyramids in Ancient Egypt. Retrieved 18 November 2003 from http://www.touregypt.net/featurestories/pyramids.htm. Ancient Egypt Essay -- Egyptian History Essays Ancient Egypt Ancient Egypt is located along the Nile River of Northeastern Africa. More specifically, it is the territory where ancients Egyptians lived in the valley of the delta and the Nile. It was a thriving civilization for more than 3,000 years, from about the time of 3300 BC to 30BC. The culture of Ancient Egypt is identified and very well known for many aspects of their ways of life. Considering the time period, they were very technologically advanced. This can especially be seen through the great pyramids and hieroglyphs that elaborately decorate the walls of them. Pyramids were not small structures. In fact the largest one was over fifty stories high. In addition they were also built completely by manual labor. Labor consisted of moving limestone blocks that weighed on average 2.5 metric tons and could weigh up to 15 metric tons. In addition they had to form these blocks, move them, and sculpt them into the great structures known as the Pyramids. As you can imagine they took several decades of day in and day out work to complete these massive structures. The hieroglyphs were also an important part of not only the Ancient Egyptian culture but the pyramids especially. They provided pictorial descriptions for burial chambers, temples, jewelry, and important statu es. Ways to decipher them were unknown until the discovery of what is known as the Rosetta Stone. It was a stone that showed the same text in three different languages. Then early in the 19th century a French scholar name Jean Francois Champollion was able to decipher it and later on aid in learning the language of the dead language of hieroglyphs. Hieroglyphs are still being deciphered to this day. Ancient Egypt was able to prosper for such a long perio... ... November 2003 from http://www.greatscott.com/hiero. Iversen, Erik. The Myth of Egypt and Its Hierolyphs In European Tradition. Princeton, New Jersey: Princeton Univeristy Press, 1993. Minnesota State University. "Hieroglyphs." Retrieved 21 November 2003 from http://www.mnsu.edu/emuseum/prehistory/egypt/hieroglyphics/heiroglyphics.html. Park, Rosalind.The Scientific Invention of Hieroglyphs or Hurrah for Pliny! Great Britain: Azoth Publications, 1997. Silverman, David P. Language and Writing in Ancient Egypt. Pittsburgh,Pennsylvania: The Carnegie Museum of Natural History, 1990. "The Pyramids of Ancient Egypt." Intercity Oz Inc. 1999. Retrieved 15 November 2003 from http://www.touregypt.net/featurestories/pyramids.htm. Winston, Alan. The Pyramids in Ancient Egypt. Retrieved 18 November 2003 from http://www.touregypt.net/featurestories/pyramids.htm.

Consider the business model Essay

The easiest way to start a design is to consider the business model that you sat down with when starting these designs. You now need to recreate that structure in Active Directory using Organizational Units as the building blocks. Create a complete Organizational Unit structure that exactly mirrors your business model as represented by that domain. In other words, if the domain you are designing is the Finance domain, implement the finance organizational structure within the Finance domain. You don’t create the entire organization’s business model within each Organizational Unit; you create only the part of the model that would actually apply to that Organizational Unit. Draw this structure out on a piece of paper. Figure 8-3 shows the Organizational Unit structure of mycorp.com’s domain. We’ve expanded only the Finance Organizational Unit here for the example. Figure 8-3. The Mycorp domain’s internal Organizational Unit structure Once you have drawn an Organizational Unit structure as a template for your Active Directory hierarchy within the domain, you can begin to tailor it to your specific requirements. The easiest way to tailor the initial Organizational Unit design is to consider the hierarchy that you wish to create for your delegation of administration. Two Tier Hierarchies A two tier hierarchy is a design that meets most company’s needs. In some ways it is a compromise between the one and Three Tier hierarchies. In this design there is a Root CA that is offline, and a subordinate issuing CA that is online. The level of security is increased because the Root CA and Issuing CA roles are separated. But more importantly the Root CA is offline, and so the private key of the Root CA is better protected from compromise. It also increases scalability and flexibility. This is due to the fact that there can be multiple Issuing CA’s that are subordinate to the Root CA. This allows you to have CA’s in different geographical location, as well as with different security levels. Manageability is slightly increased since the  Root CA has to be brought online to sign CRL’s. Cost is increased marginally. Marginally speaking, because all you need is a hard drive and Windows OS license to implement an Offline Root. Install the hard drive, install your OS, build your PKI hierarchy, and then remove the hard drive and store it in a safe. The hard drive can be attached to existing hardware when CRLs need to be re-signed. A virtual machine could be used as the Root CA, although you would still want to store it on a separate hard drive that can be stored in a safe. Three Tier Hierarchies Specifically the difference between a Two Tier Hierarchy is that second tier is placed between the Root CA and the issuing CA. The placement of this CA can be for a couple different reasons. The first reason would be to use the second tier CA as a Policy CA. In other words the Policy CA is configured to issue certificates to the Issuing CA that is restricted in what type of certificates it issues. The Policy CA can also just be used as an administrative boundary. In other words, you only issue certain certificates from subordinates of the Policy CA, and perform a certain level of verification before issuing certificates, but the policy is only enforced from an administrative not technical perspective. The other reason to have the second tier added is so that if you need to revoke a number of CAs due to a key compromise, you can perform it at the Second Tier level, leaving other â€Å"branches from the root† available. It should be noted that Second Tier CAs in this hierarchy can, like the Root, be kept offline. Following the paradigm, security increases with the addition of a Tier, and flexibility and scalability increase due to the increased design options. On the other hand, manageability increases as there are a larger number of CAs in the hierarchy to manage. And, of course, cost goes up.