Carnivores of the Kalahari Desert Free Essay Example, 2250 words

The average amount of rainfall it receives per year is estimated to be between 76 and 190 mm of rain per year (Thomas & Shaw, 2009). The area is surrounded by the Kalahari basin, which covers about 2,500,000 square kilometers extending further into Namibia, South Africa and Botswana, and intruding into sections of Zimbabwe, Angola and Zambia. The Okavango is the only permanent river that flows into the delta in the northwest, forming wetlands that are rich in wildlife (Thomas & Shaw, 2009). Primeval riverbeds known as the Omuramba pass through the Central Northern stretches of the Kalahari and supply stagnant pools during the rainy season (Ownes, 2012). In the past, the riverbeds were mostly havens for wild animals in the desert ranging from elephants to giraffes, and predators such as lion and cheetah (Ownes, 2012). Currently, the riverbeds are mainly grazing lands although some predators such as leopard and cheetah can still be found. Climate The word Kalahari is acquired from the Tswana term Kgala that can be directly translated to mean a waterless place (Owens, 2012). We will write a custom essay sample on Carnivores of the Kalahari Desert or any topic specifically for you Only $17.96 $11.86/pageorder now The Kalahari is vastly covered by red sand and does not have any permanent surface water. However, the Kalahari cannot be referred to as a true desert. Sections of the Kalahari receive 250 millimeters of erratic rainfall every year and are quite vegetated. The Kalahari is only actually arid in the southwest with less than 175 mm of rain every year, making the desert a fossil desert. The temperatures during summer ranges from 20 to 50 o C (Thomas & Shaw, 2009). The Kalahari Desert is extremely hot during the day. There are however no cloud to keep the heat on the ground at night. Therefore, it is often extremely cold at night. The desert sometimes experiences thunderstorms during the summer. Carnivores in the Kalahari Desert Spotted Hyena Spotted hyenas survive at relatively very low densities compared to other areas(Mills, 2008). They are quite specialized on gemsbok calves which are thinly and widely distributed. Their versatility enables them to travel vast distances to find them. They live in slightly larger clans of up to 80 hyenas making up one clan. Unlike other carnivores in the Kalahari, the spotted hyenas often hunt any species (Mills, 2008). The only exemption they make is on the buffalo and the giraffe, which are a bit too large for them. Unlike the brown hyena, the spotted hyena is a predator and not a scavenger. It is the only carnivore capable of coexisting in the same ecological niche as the lion, and pose as some form competition when it comes to hunting of the prey.

Project Management A Project Manager Essay - 1533 Words

In project management, there are many methods to handle how the project should be completed, how an ethical situation should be handled, what types of decisions should be made. Furthermore, how much knowledge the project manager should possess, their focus of completing the job on budget and schedule, and understand the scope, as well as, knowing how to communicate. When I completed OGL 320: Foundations of Project Management, I understood the hard work the project manager had to endure to complete a successful project. They are the individuals who are responsible, knowledgeable, and are great communicators with a mindset of completing an outstanding project. I feel that I boosted my knowledge and grew throughout the OGL 321: Project Leadership class during this Fall of 2016. Sharing our experiences regarding the simulations to the module discussion paper that are completed at the end of each module has acquired me to understand what can be accomplished with different strategies. Each module discussion paper provided me an insight of the project manager’s challenges, and what are the main important points to complete a project with success. In addition, this class assisted me in recognizing and concentrating in areas, such as, principles, practices, and leadership. Project management requires a solid management plan focusing on scope and scheduling risks, communication, good decision making, how to deal with uncertainties, ethics, and to practice the situational leadershipShow MoreRelatedProject Management Project Manager Project1011 Words   |  5 PagesProject managers cannot, and must not, do everything. They must rely on the project team to complete the project work. Project managers must find ways to motivate the project team to complete the work. There is a tendency, in many projects, for the project team to be very excited about the project at the start and then excitement wanes as the project moves toward completion. The project manager must coach and mentor to develop the project team to ensure the excitement, willingness, and dedicationRead MoreProject Management For A Project Manager Essay1460 Words   |  6 Pagesavailable to support the project manager In order to run a project, the manager needs support with different things such as resources, tools and methodologies. Project Resources In order to make a project, the project manager needs some help with the project resources. Resources like information will be useful to Feltram Solutions Inc. as current information is required in order to develop new project and features of it. With the help of old/current information, the manager can include new functionsRead MoreProject Management : A Project Manager1684 Words   |  7 Pages CT5022 Project Management ASS 1 Identify and discuss attributes that you consider to be key to the role of an IT project Manager, focusing on how these attributes combine to facilitate good project management. Jennifer Quinn s1306997 Identify and discuss attributes that you consider to be key to the role of an IT project Manager, focusing on how these attributes combine to facilitate good project management. â€Æ' Identify and discuss attributes that you consider to be key to the role ofRead MoreProject Management : A Project Manager1747 Words   |  7 PagesIntroduction Project management (PM) is the vocation of seeing that projects are completed on time, within budget, and perform to the standard that the stakeholders are expecting. There are PM degrees available at the Associate, Bachelor, Graduate, and Ph.D. levels of study; degrees are available on campus and online from many well-known and highly rated institutes. However, many employers view the Project Management Professional (PMP) certificate as even more important than a degree. Project managersRead MoreProject Management : A Project Manager1120 Words   |  5 PagesProject management involves carefully organized and planned efforts channeled towards the accomplishment of a particular task. Projects encompass activities such as implementing new computer systems or constructing a new office. Projects require careful monitoring from the start to the completion. One person mandated to take charge of projects is a project manager. Project managers experience complications from project manag ement. The challenges arise from the dynamic environment in which the managersRead MoreProject Management : The Project Manager1292 Words   |  6 PagesHowever, ethically, no person should be singled out for project failure unless it is the project manager. In the end, he or she is the one assigned the ultimate task of ensuring the project is completed. Although the project manager is in charge of ensuring the task gets completed, sometimes a task can fail despite the project manager’s best efforts. In these cases of project incompletion or failure, it should be said that the team failed. This is the most ethical result in this sense becauseRead MoreProject Management : Project Manager2272 Words   |  10 PagesIdeally, the requirement for an IS project would be specified in some detail before planning begins. If the requirement is not detailed enough, what steps can the project manager take to improve the likelihood of the project’s success? If the project manager does not know what the requirements for a project are, he can’t effectively begin to make a project plan. The level of detail required changes depending on the scope of the project. The more complicated the project (i.e. the larger the scope), theRead MoreProject Management : A Project Manager1030 Words   |  5 Pagesbetween a project manager and a project leader. This is because a good project manager really is a good project leader. He or she has gone through specific training to take them from just being a project manager to being an influential and motivational project leader. There are these additional skills a project manager has to develop to take them from simply being a project manager to a project leader who inspires people to higher achievements and accomplishments and not just managers of their workRead MoreProject Management : A Project Manager2515 Words   |  11 PagesA Project manager is the individual who has the general obligation re garding the fruitful start, arranging, outline, execution, checking and controlling. The work s title is used every bit a component of the evolution, construction planning, data innovation and a broad scope of commercial project that deliver items and giving medications. The project supervisor must take in a mix of aptitudes including a mental ability to ask entering inquiries, recognize implicit suppositions and resolution clashesRead MoreProject Management : A Project Manager2065 Words   |  9 PagesA project is managed by a project manager. It has to be managed so there will not be any mistake during the production. A project manager has to be an organized, and enthusiastic person who can lead the project to success. A good project managers make the goal by their own and they use their skills and share their purpose to the project team. Becoming a project manager is difficult. They have a lot of roles to maintain the project running fluently. They should calculate all the things needed for

Critical Analysis on the Philosophy of Education Free Essays

A philosophy of education, as a requirement for admission to any sort of education program, has within it the inherent fault that it may not be a truthful reflection of the applicant. Defining an instructor’s philosophy, in regards to any area of supposed expertise, often results in page upon page of self-platitudes, false impressions and the required buzzwords. Does such an exercise actually reflect on the true actions and intentions of the instructor in regards to his methodology, success and creativity in the classroom setting? Does it accurately reflect his relationship to his students, and vice versa? Is such a philosophy something that can be accurately described in mere words, or is it something better viewed in the physical space of learning? It appears that most philosophies beg, borrow and steal from the latest theories of what is considered to be the well-rounded educator. We will write a custom essay sample on Critical Analysis on the Philosophy of Education or any similar topic only for you Order Now The writer is forced to fill the required assignment with various educational stances and statements while often never developing their own personal mission statement. They are often afraid to say what they truly believe in, instead stating what they think those that judge the work are seeking. Such a philosophy can be seen on paper, but is it visible in the classroom setting? Can you tell how talented, or horrible, a teacher I am from this simple reading? Or would a trip into my classroom for an entire day give a more comprehensive and factual assessment of my true educational philosophy. My philosophy, or what I practice everyday in the educational setting, is simple and memorable. This philosophy, which has so far been successful in my short career, is to actually know your students and treat them as individuals. When teaching becomes difficult, always remember that they are only kids. Each one is vastly different than the next, and no two are even remotely alike. Each has varied interests, faults, problems, successes and distractions. Each has different, though not necessarily wrong, expectations, results and goals. There are no perfect students, and each must be evaluated on their own personal gains. The first step in accomplishing this philosophy of respect is focused, as everything should be, on the student. So often teachers grumble about the absence of respect aimed towards them, all the while ignoring the need for the student’s own validation of worthiness as an individual and simply not an occupied seat. Every year, six or seven students are removed from other classes and placed into mine. In each instance, demeaning remarks from an instructor orlack of communication? is the reason for the switch. I have found adapting my approach towards these students is often all that is needed to seem some educational gains. Does this mean that every student succeeds? Of course not, but those that make the effort without simply giving up do succeed, even if it is unnoticed by others. I attempt to do simple enforcement of this philosophy everyday in, and out of, the classroom. For example, I attempt to avoid being patronizing and condescending. I recommend teachers actually listen to the students when they talk, and when they do not utter a word. Treat all students the same, but also as individuals who are each unique in their own incredible way. They are just kids, so don’t expect perfection. It is fine to set reasonable and challenging goals for students in relation to their skills and talents, but to expect them to live up to unattainable standards, such as your own, dooms them to failure. Know their limitations, and your own. All of this involves the instructor to take the time, effort and interest in actually knowing each student as the individual they truly are, both in and outside of the school setting. Failure to do so limits the effectiveness of any type of learning endeavor. The only losers in such a situation are the students themselves and may be detrimental to the entire educational process. Such loss that may possibly be subtle enough to go unnoticed by all those involved. My education philosophy is not one thousand words in length, nor do I believe that any such personal mission statement should be expected to accomplish this feat. To do so would cloud its importance in vague assumptions and possibly pompous platitudes. It should be seen every day in the success, failure, effort, sacrifices, and abilities of the individual student, not in words and phrases with questionable intentions. Such a value statement can only be seen in the educational setting. How to cite Critical Analysis on the Philosophy of Education, Papers

Modern Advancements Have Made the Life Easy free essay sample

The pace of development and change has accelerated exponentially since the beginning of the 20th century and continues today, affecting many aspects of daily modern life. Good morning one and all. I, stand before you to express my supporting views on the topic that modern advancements have made the life easy. There are different fields in which modernisation has affected our lives and have helped us in saving time, cost and efforts thus making human life more enjoyable and meaningful. The areas are many but but due to time constant I have chosen only four key fields which will clearly support the topic when we will look at their past and present scenarios and advantages to mankind. These are- Advancements in Information technology, Medical field, Robotics and Transportation. Information technology It used to take weeks to pass on the information through post which is now possible within seconds with the help of Computers and internet. We will write a custom essay sample on Modern Advancements Have Made the Life Easy or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page Computers can also keep all your records safe, mobile, tidy and easily accessible which was not possible earlier. Using internet, One can work from home and learn about almost anything. Transportation One of main reasons why consumer goods are cheap and available in developed countries is because of advances in transportation. You can eat food, wear clothes and play games all made in different, far-off countries because of planes, trucks, supertankers and roads that didnt exist a century ago. You can also travel to almost anywhere in the world in a day or two, instead of months. Everything is more accessible. Robotics Robotics is the latest advancement in the field of technology and science. There are many advantages of robots such as Robots rarely make mistakes and are more precise than human workers. They can produce a greater quantity of work in a short amount of time. They can work at a constant speed with no breaks. They can do any kind of work they are programmed to. They reduce human efforts and time and can do various dangerous tasks which a man simply cannot. Medicines Advances in medicine have allowed people to live longer and healthier lives. Antibiotics and vaccines might have saved your life, and have definitely kept someone you know alive. With advancement in the medical field, the average life expectancy has gone up to 65 years which was 57 years in 1990. This fact clearly indicates that medical advancement have improved the health of masses. To conclude, we must agree from above examples that modern advancements have definitely made our lives easy. Thank you.

Employee handbook inspections and spills

Workplace accidents are a major concern to food stores’ managers and their workers. More often, accidents result from wet flows, spills, and sharp cutleries. In all grocers, managers and safety managers supervise safety responsibilities. They are supposed to ensure that the safety requirements of the employees and the clients are fulfilled.Advertising We will write a custom essay sample on Employee handbook: inspections and spills specifically for you for only $16.05 $11/page Learn More As such, managers and safety managers ensure that appropriate systems are put in place to enable employees verify safety hazards. Similarly, these officials ensure that all safety measures are upheld. Based on the above responsibilities, this article seeks to highlight how Paul’s Grocer management team should organize its routine checkups and inspections, meet its inspection standards, and handle its spills. In their inspection and spill programs, the grocer ’s management team should identify regulations and recommendations that are applicable in their jurisdiction. These requirements should aid the management team in coming up with the appropriate safety policies. Similarly, the organization’s safety manager should coordinate outside and internal inspections. When the government or regulatory agencies are conducting outside inspections, organization’s safety manager should accompany the inspectors to note down the violations and recommendations. Similarly, during the inspections the safety manager should be ready to give explanations about any cases of dubious practices or equipments within the grocer’s premises. Thereafter, the safety manager should forward the necessary recommendations to the grocer’s management team. Equally, in the recommendations the safety manager should note down features pointed out by the inspectors that may require policy change. Apart from the external inspections, Paulâ₠¬â„¢s Grocer should put in place an efficient internal inspection team. The internal inspection team can comprise of the grocer’s staff members or members of a corporate entity. Since the grocer’s safety manager cannot provide the safety of the whole business premises alone, he or she should disseminate responsibilities to the subordinates. Through this, he or she should harmonize all the employees’ efforts. To achieve this, the safety manager should set up a safety committee to oversee the implementation of these in initiatives.Advertising Looking for essay on business economics? Let's see if we can help you! Get your first paper with 15% OFF Learn More Similarly, the safety committee should hold meetings with the safety manager once in a week. During the meetings, they should review the previous weeks’ inspection reports, new safety requirements, safety suggestions, accidents, and any other violations. Similarly, during the meetings the m embers should be allowed to discuss safety suggestions. In general, the safety committee will be required to forward their inspection reports, spill reports, and recommendations from their fellow employees. Through the safety committee, the grocer’s management team should encourage all their employees to have control over their work area. As such, employees should ensure that their working place is kept organized, free from spills, and that supplies are kept on the right shelves. Usually, large retail shops announce their safety sweeps to its customers and employees in time to avoid the inconveniences. However, for Paul’s Grocer, which operates for 24 hours, the announcements would not be necessary. Instead, the grocer should ensure that their cleaning staff conducts safety sweep once in a week. This operation should be conducted when the clients’ turnover is low between 8pm and 8am. To ensure regular spills are removed, the grocer’s management team shoul d make sure their employees inspect the grocer’s pathways for spills and safety hazards every few minutes. The grocer’s safety manager should note that a client or an employee requesting for a cleaning staff to clean spills is not appropriate. Therefore, every employee in the grocer should be trained to handle the spills while the cleaning staffs are being reached for help. Despite the fact that the grocer employs cleaning staffs, all the employees should be able to handle spills and other hazards, and should be ready to clean the spills when the cleaning agents are not available. The number of individuals required to handle spills depends on the quantity of spills. Spills should be handled using appropriate equipments. When handling spills, employees should ensure that they wear protective clothing. In addition, the safety manager should ensure that spill station is set up within the grocer. The spill station should have the necessary cleaning equipments such as towel s, mops, brooms, and cleaning solutions. Equally, the spill station should be accessible to all employees. To be certain that all inspection and spill policies are met, safety manager should ensure that a log is maintained. A grocer’s log should indicate the intervals of internal inspections. During the external inspections, a log will prove to the external inspectors that regular checkups, cleanups, handling spills, and other safety hazards are conducted in accordance with the safety requirements. Since all the employees would be required to handle spills occasionally, the grocer’s management should ensure that it trains its employees on inspection requirements and spill handling techniques.Advertising We will write a custom essay sample on Employee handbook: inspections and spills specifically for you for only $16.05 $11/page Learn More The training programs should meet the standards set by the regulatory agencies. If the above proposals and policies are observed, Paul’s Grocer will not only be able to avoid accidents related to spills, but will also be able to meet safety standards required by the government and local authorities. This essay on Employee handbook: inspections and spills was written and submitted by user Bruce F. to help you with your own studies. You are free to use it for research and reference purposes in order to write your own paper; however, you must cite it accordingly. You can donate your paper here.

Syllabus - Tells You Everything You Need To Know About Your College Class

Syllabus - Tells You Everything You Need To Know About Your College Class When I first started college I had no idea what my professor meant when she said she was about to distribute the syllabus. Over the rest of that first day I came to understand that a syllabus is a guide to the course. Many students dont take advantage of the information provided in the syllabus to plan their semester. The syllabus contains all of the information you need to know regarding what is expected of you and what you need to do to prepare for each class. Heres what you will find on the syllabus distributed on the first day of class: Information about the Course Course name, number, meeting times, number of credits Contact Information The professor lists the location of his or her office, office hours (times that he or she is in the office and available for meeting with students), phone number, email, and website, if relevant. Plan to use a professors office hours to get the most out of class. Required Readings Textbook, supplemental books, and articles are listed. Books generally are available in the campus bookstore and sometimes are on reserve in library. Articles are sometimes offered for purchase in the book store, other times are on reserve in the library, and increasingly common, are available on a course or library webpage. Read before class to get the most out of class. Course Components Most syllabi list the items that compose your grade, for example, midterm, paper, and final, as well as the percent each item is worth. Additional sections often discuss each course component. You might find a section on exams, for example, that lists information about when they occur, what form they take, as well as the professors policy on making up exams. Pay particular attention to sections discussing papers and other written assignments. Look for information about the assignment. What are you expected to do? When is the final assignment due? Are you expected to consult the professor prior to beginning your paper or project? Is a first draft required? If so, when? Participation Many professors count participation as part of the grade. Often they will include a section in the syllabus describing what they mean by participation and how they assess it. If not, ask. Professors sometimes say that they simply record it and provide few details on how. If thats the case you might consider visiting during office hours in a few weeks to inquire about your participation, whether it is satisfactory, and whether the professor has any suggestions. Many times participation is used as a synonym for attendance and professors may list it in simply order to address students who do not show up for class. Class Rules/Guidelines/Policies Many professors provide guidelines for class behavior, often in the form of what not to do. Common items address the use of cell phones and laptops, tardiness, respecting others, talking in class, and attention. Sometimes guidelines for class discussions are included. In this section or sometimes a separate section, professors often will list their policies regarding late assignments and their make-up polices. Pay particular attention to these policies and use them to guide your behavior. Also recognize that you can shape professors impressions of you with appropriate class behavior. Attendance Policy Pay particular attention to the professors attendance policies. Is attendance required? How is it recorded? How many absences are permitted? Must absences be documented? What is the penalty for unexcused absences? Students who dont pay attention to attendance policies can be unexpectedly disappointed with their final grades. Course Schedule Most syllabi include a schedule listing due dates for reading and other assignments. Reading List Reading lists are particularly common in graduate classes. Professors list additional readings that are pertinent to the topic. Usually the list is exhaustive. Understand that this list is for reference. Professors likely will not tell you this, but they dont expect you to read the items on the reading list. If you have a paper assignment, however, consult these items to determine if any are of use. One of the simplest and best pieces of advice I can offer you as a student is to read the syllabus and make note of policies and deadlines. Most policy, assignment, and deadline questions I receive can be answered by, Read the syllabus - its in there. Professors dont always remind you of upcoming assignments and due dates. Its your responsibility to be aware of them and to manage your time accordingly. Take advantage of the course syllabus, an important guide to your semester.

Evaluating Arguments about consumerism Essay Example | Topics and Well Written Essays - 1000 words

Evaluating Arguments about consumerism - Essay Example The paper summarizes and analyzes the two essays that present viewpoints on consumer culture in America before evaluating their efficacy. In his essay ‘The Year Without Toilet Paper, Mr. Green analyzes the lives of three members of a family (Mr. Colin, his wife and two-year-old daughter Isabella who wears organic cotton diapers) during their one-year experimental lifestyle the named ‘No Impact. Green explains that the rule of this lifestyle keep changing though the necessary regulations include preparing and taking natural foods grown not more than a two hundred and fifty mile radius of Manhattan city. Additionally, Mr. Colins family shops for no other household goods apart from the said foods thereby producing no trash in the form of paper. The family has a home composter in which only organic and biodegradable waste is dumped and consumed by worms. The most intriguing part the familys No Impact lifestyle is the fact that no member of the family uses any form of carbon-fueled transportation (Penelope 1). Mr., Colin Beavan, who is a senior writer, decided to embark on the No Impact year after his agent discredited all other possible possibilities that would sell as a book. This is an implication that Mr. Colin was doing this not only for the hope that people will tread more lightly on the earths resources, but also for the popularity of the book he was about to write. He had to turn his family’s lifestyle upside down in order to conform to the rules and regulations of the No Impact year. As a matter of fact, the family embraced full environmentalism to an extent that a visitor would hesitate to visit the bathroom for fear of failing to get tissue paper in there; hence the title ‘The Year Without Toilet Paper’ (Penelope 1). Colin’s decision to transform the lifestyle of his family to a No Impact lifestyle was not just inspired by the urge to protect some sort of â€Å"pristine

Descartes and the Existence of Evil Demon Essay

Descartes and the Existence of Evil Demon - Essay Example Central to his argument is the fact that his knowledge of God is anchored on a distinct idea on the existence of a supreme being (Marion, 2008). As such, there must be the existence of an idea first before a given claim of body of knowledge is verified. For Descartes, this distinct idea resided in his mind. It is this idea that gave him the essence of God as a supreme being. It is an idea that could not be verified through empirical methods. The existence of an Evil Demon, in line with the thinking of Descartes, can only obtain if it is backed by a distinct idea.   There must first exist the essence of the Evil Demon that is developed into Descartes mind in order for him to make a claim about the existence of such a being. One of the central arguments upheld by Descartes is that essence relates to existence. It would follow logically that the absence of essence effectively eliminates all possibilities of existence. Without the essence of the Evil Demon in distinct form it would be vacuous to assert any claim of such an existence. Therefore, this would mean that Descartes could claim the existence of God but not make any assertions on whether or not some Evil Demon actually exists (Marion, 2008). Proof of such existence could be derived from other serious arguments, or by employing some logical claims outside the boundaries established by Descartes methods.   Descartes knowledge of God was based on the theory of ideas which people can relate with. He believed that it is possible for things to exist without their very nature of existence being confirmed by any evidence. He did not consider it necessary to seek out for measure of quantifiable evidence that would offer evidence for the existence of God. According to him, the mind can generate knowledge of its own through the power of intuition. The practice of intuition basically demands changing the mind to the essence of ideas without establishing the evidence of experience or

Omeprazole Research Paper Example | Topics and Well Written Essays - 500 words

Omeprazole - Research Paper Example They inhibit this pump and hence lead to a reduction in the production of the acid. The drug has many indications which include the ulcers of the stomach which are the primary indication. Other indications include disturbances caused by the acid in the stomach and heartburn. It may also be given to relive chronic cough. Certain medications like non-steroidal anit-inflammatory drugs cause damage to the lining of the stomach and the proximal part of the intestine. It is also considered to assist in reducing the risk of cancer of the esophagus. Omeprazole can be given to avoid this damage. It is also indicated as a pre anesthetic drug before the administration of general anesthesia. Omeprazole can be taken orally and it is also available in the form of injections. The oral form of the drug is coated to prevent damage to it in the stomach by the acid. The action of the drug lasts for approximately 24 hours and it is extremely important to be understood that for complete results, the drug needs to be taken for at least 3 to 4 days. The drug may have a few adverse effects which include headache and pain in the abdomen. It may result in other gastrointestinal problems which include nausea, vomiting, diarrhea or constipation. It is also seen that treatment with this drug for prolonged periods of time may result in increased levels of gastrin in the blood. The drug is also associated with reduction in the absorption of the vitamin B12. Also as the drug leads to reduction of acidity in the stomach, it may hinder the absorption of drugs like digoxin which require an acid medium for their absorption. The susceptibility of infections of the gastrointestinal tract and the respiratory system also increase with this drug.

Coordination Chemistry of Bidentate Ligands Research

Coordination Chemistry of Bidentate Ligands Research Elham Torabi Farkhani Mehrdad Pourayoubi Pavel V. Avdreev Katarina Introduction The coordination chemistry of bidentate ligands has been studied for over thirty years [reference]. The bidentate ligands with phosphoryl and thiophosphoryl groups have been used as effective coordinating agents in the different metal chemistry, in most cases the reports were attributed to bonding between the metal cation and specific Lewis sites on the ligand, itself has number sites with potential to bind metal ions, such as nitrogen, sulfur and oxygen. In order to recent report Hg metal ion is known to have strong affinity for nitrogen and sulfur Lewis sites [reference] which our work here is done bonding between Hg metal atom and sulfur in ligands. A search of the Cambridge Structural Database (CSD) [reference] yielded a data set of 76 purely molecular structures to be used for study of coordination of metal atom with a P(S)[N][O]2 skeleton of ligand. Thus there are a number of reports on molecular structure contain M-S=P fragments with different metal atoms [reference]. An inves tigation of the reports reveals that there isn’t any publication with Hg metal, also we haven’t found any precise study on the effect of all interactions, including coordinating linkages and intermolecular interactions on the structure of Hg(II) complexes with bisthiophosphoryl ligands. Accordingly we have carried out a study on mercury (II) chloride with two different bidentate ligand with general formula (OEt)2P(S)-X-P(S)(OEt)2 where X=1,4-NH-C6H5-NH and piperazine (scheme ). Reaction of two ligand with HgCl2 generated binuclear complex C1 and C2. All compounds were charactrized by IR and NMR (1H, 13C and 31P NMR) spectroscopy and mass analysis. The structure of ligand 1 and two complexes C1 and C2 were determined by X-ray crystallography. Experimental Materials and methods Mercuric chloride (99.5%), O,O†²-diethyl chlorothiophosphate (OCH2CH3)2P(S)Cl (97%), diethylenediamine (97%), 1,4-phenylenediamine (99%) (Aldrich), acetonitrile (99%) and methanol (99%) (Merck) were used as supplied. Acetonitrile was dried with P2O5 and distilled prior to use. The 1H, 13C and 31P NMR spectra were recorded on a Bruker Advance 400 spectrometer at 400, 101 and 162 MHz, respectively. 1H chemical shifts were determined relative to Si (CH3)4. 31P chemical shift was measured relative to 85% H3PO4 as external standard. Mass spectra were performed using a Varian Star 3400 CX mass spectrometer. Infrared (IR) spectra were recorded on KBr disk using a Buck 500 scientific spectrometer. Elemental analysis was performed using a Thermo Finnigan Flash EA 1112 apparatus. X-ray data collection was performed with a Xcalibur, Sapphire3, Gemini diffractometer with graphite monochromator. Synthesis General procedure for the preparation of ligands The ligands were synthesized from the reaction of 2 mmol (OCH2CH3)2P(S)Cl with 1 mmol of the corresponding diamine (diethylenediamine and 1,4-phenylenediamine) in presence of Et3N as HCl scavenger in CH3CN at 0ËÅ ¡ C. After stirring for 24 h, the solvent was evaporated and the residue was washed with distilled water and dried. Chemical structures are shown in scheme 1. Physical and spectroscopic data of the ligands are presented below: 1, 4 [(C2H5O)2P(S)N]2C4H8 (L1): Mp: 105ËÅ ¡ C. Anal. calc. (%) for C12H28N2O4P2S2: C: 36.88; H: 7.17; N: 7.17, S: 16.39, found: C: 37.81; H: 7.16, N: 7.26, S: 15.7. IR data (KBr, cm-1): 2990, 2903, 2864, 1449, 1387, 1339, 1264, 1151, 1098, 1029, 972, 792, 714.1H NMR (400 MHz, DMSO-d6) ÃŽ ´: 1.22 (t,3JH-H= 7.1 Hz, 12H, CH3), 3.12 (m, 8H, C4H8), 7.00 (m, 8H, CH2), 13C NMR (101 MHz, DMSO-d6) ÃŽ ´: 15.57 (d, 3JP-C = 8.08 Hz, 4C, CH3), 44.84 (s, 4C, C4H8), 62.45 (s, 4C, CH2), 31P NMR (162 MHz, DMSO-d6) ÃŽ ´: 73.64. MS (70 eV, EI): m/z (%) = 390 (28), 235 (43), 195 (100), 153 (99), 120 (96), 96 (100), 28 (66). 1, 4 [(C2H5O)2P(S)NH]2C6H4 (L2): Mp: 105ËÅ ¡ C. Anal. calc. (%) for C14H26N2O4P2S2: C: 40.73, H: 6.30, N: 6.78, S: 15.51, found: C: 41.15, H: 6.34, N: 7.01, S: 15.57. IR data (KBr, cm-1): 3268, 2980, 1515, 1479, 1380, 1278, 1218, 1168, 1023, 959, 816, 726, 646. 1H NMR (400 MHz, CD3CN) ÃŽ ´: 1.22 (t,3JH-H= 7.1 Hz, 12H, CH3), 3.12 (m, 8H, C4H8), 7.00 (m, 8H, CH2), 13C NMR (101 MHz, CD3CN) ÃŽ ´: 15.57 (d, 3JP-C = 8.08 Hz, 4C, CH3), 44.84 (s, 4C, C4H8), 62.45 (s, 4C, CH2), 31P NMR (162 MHz, CD3CN) ÃŽ ´: 73.64. MS (70 ev, EI): m/z (%) = 412 (94), 411 (100), 168 (26), 107 (89), 96 (91), 92 (39), 65 (87), 28 (88). General procedure for the preparation of complexes The complexes were prepared by a solutions of 2 eq. HgCl2 in 15 ml of methanol was added drop wise to a solution of 1 eq. the corresponding ligand in 15 ml of methanol. The clear solution was stirred under reflux for 24h. Crystals suitable for X-ray diffraction were obtained from slow evaporation of the solution at room temperature. Physical and spectroscopic data of the complexes are given below:  µ-{1, 4-[(C2H5O)2P(S)N]2C4H8}(HgCl2)2 (C1): Mp: 105ËÅ ¡ C. Anal. calc. (%) for C12H28Cl4Hg2N2O4P2S2: C: 15.41; H: 2.99; N: 2.99, S: 6.84, found: C: 15.67; H: 2.91, N: 2.99, S: 5.74. IR data (KBr, cm-1): 2976, 2895, 1444, 1383, 1344, 1266, 1121, 1037, 967, 804, 772, 702.1H NMR (400 MHz, CD3CN) ÃŽ ´: 1.22 (t,3JH-H= 7.1 Hz, 12H, CH3), 3.12 (m, 8H, C4H8), 7.00 (m, 8H, CH2), 13C NMR (101 MHz, CD3CN) ÃŽ ´: 15.57 (d, 3JP-C = 8.08 Hz, 4C, CH3), 44.84 (s, 4C, C4H8), 62.45 (s, 4C, CH2), 31P NMR (162 MHz, CD3CN) ÃŽ ´: 73.64.  µ-{1, 4 -[(C2H5O)2P(S)NH]2C6H4}(HgCl2)2 (C2): Mp: 105ËÅ ¡ C. Anal. calc. (%) for C14H26Cl4Hg2N2O4P2S2: C: 17.59; H: 2.72; N: 2.93, S: 6.70, found: C: 17.85; H: 2.69, N: 2.93, S: 6.53. IR data (KBr, cm-1): 3211, 2990, 1615, 1512, 1479, 1380, 1274, 1214, 1161, 988, 824, 633. 1H NMR (400 MHz, CD3CN) ÃŽ ´: 1.22 (t,3JH-H= 7.1 Hz, 12H, CH3), 3.12 (m, 8H, C4H8), 7.00 (m, 8H, CH2), 13C NMR (101 MHz, CD3CN) ÃŽ ´: 15.57 (d, 3JP-C = 8.08 Hz, 4C, CH3), 44.84 (s, 4C, C4H8), 62.45 (s, 4C, CH2), 31P NMR (162 MHz, CD3CN) ÃŽ ´: 73.64. Result and discussion IR and NMR spectroscopy Mass spectroscopy The nature of the fragments observed in the mass spectrum often provides as clue to the molecular structure. The fragmentation pathways of ligands 1 and 2 were studied by electron ionization at 70 eV experiment and revealed a molecular ion peak [M]+ at m/z (%) of 390 (28) and 412 (94) for 1 and 2, respectively. The formation of the [M-1] specie from the parent ion of compound 2 was shown to exclusively involve an aromatic hydrogen atom; our results were in good agreement with previously published results. [reference]. The previous paper has been shown that dialkyl alkanephosphonates ROCH2CH2P(O)(OR)2 undergo a McLafferty rearrangement in which a ÃŽ ³ hydrogen from the alkylphosphorous moiety migrates to the phosphoryl group and a molecule of olefin is eliminated from the molecular ion [reference]. The mass spectra of compound 1 and 2 with the same structure have confirmed previously reported mechanism. The peak related to the C2H4 radical-cation with m/z = 28 are shown for two struct ures. Relative peak height = relative abundance as measured from this ion in the compound 1 and 2 are 66 and 88. For the compound 1, the base peak is appeared at m/z = 153 (P(S)(OEt)2) and in the compound 2, the base peak is appeared at m/z = 411 (M-1) fragment. For 1, the main fragmentation is based cleavage of N-P bond then produced A ion and P(S)(OEt)2 with m/z 153. The ion of A following three pathways: (1): A ion can produce a stabilized ion by loss of ethylene via the McLafferty rearrangement which generate the odd mass ion m/z 181 that it operates for ion m/z 181 capable of electronic shift involving a six-membered cyclic transition state in the molecule skeleton given in scheme 1. This will then stabilize to an even mass ion m/z 180 by elimination of an H radical. (2): in this pathway produce the ion at m/z 147 that formed through a three- membered ring as transition state by loss of two molecule of ethanol. The ion of m/z 147 indicating the relatively low stability of the P-O bond to the molecule of A in comparison with that of the P-N bond. (3). The ion at m/z 84 is formed through two step, the first is cleavage of P-N bond then in second step is formed via a 1,2 hydride shift by loss of a molecule of P(S)(OEt)2 [reference]. The same kind of rearrangement is observed for 2 and the main fragmentation is based cleavage of N-P bond then produced molecule ion with m/z 107. Scheme 1. Fragmentation pathway of compound 1 X ray crystallography Complexes of 1 and 2 were crystallized in the orthorhombic space group Pbca Triclinic with space group P, respectively. Crystal data, data collection and structure refinement details are summarized in Table 1 and selected bond lengths and angles are given in Tables 2 and 3. The asymmetric unit of complexes of 1 and 2 consist of one Hg2+ ion, two Cl and one half crystallographically independent ligand (Fig 1). There are two different types of Hg-Cl bonds that included bridge Hg1-Cl2 bond (2.5904(17) Ã… in 1 and 2.4852 (7) Ã… in 2) connect the molecule into one dimensional chain extended along the c axis and terminal Hg1-Cl1 bond (2.369(2) Ã… in 1 and 2.4295 (9) Ã… in 2) linked to adjacent ones by intermolecular interaction into a chain parallel to b axis in 1 and a axis in 2. (Fig 2). So, the Hg atom adopts an Hg[Cl]3[S] coordination environment in this compound with the highly distorted tetrahedral geometry of the Hg(II) center that can be better described as a seesaw structure which two chloride atoms and Hg atom [ Hg1, Hg1, Cl2] is planar, one chloride and sulfur atoms in the pivot position. The different bond distance from the  µ-chloride atoms performed and refer to asymmetry of the halogen bonds (2.5904 (17), 2.6820 (17) Ã… in 1 an d 2.4852 (7), 2.8273 (8) Ã… in 2) and they are compared to the terminal bond of Hg-Cl slightly extended. Some selected bond angles specify the distorted tetrahedral geometry at the Hg(II) center in complex 1 are as follows: Cl1—Hg1—S1 130.91 (7) °, Cl1—Hg1—Cl2 110.98 (7) °, S1—Hg1—Cl2 104.59 (6) °, Cl1—Hg1—Cl2i 108.29 (8) °, S1—Hg1—Cl2i 105.96 (6) ° , Cl2—Hg1—Cl2i 87.47 (5) °, Hg1—Cl2—Hg1i 92.54 (5) ° and P1—S1—Hg1 98.40 (8) °. In ligand L1, the phosphorus atom has a distorted tetrahedral [N]P(S)[O]2 configuration with the bond angles in the range of 101.77 (18) ° [O2—P1—S1] to 115.80 (19) ° [O1—P1—S1]. The P=S bonds of ligand are in a trans orientation is showing respect to each other and that the sulfur atom is coordinated to the mercury center. As a result of coordination to the mercury center, as expected, the P=S bond length (P (1)–S (1) 1.97 (9) Ã…) is slightly longer than that of the free ligand The crystal structure of the complex 1 generated by the O1†¦S=P interaction along c-axis. As a result of these interactions, One-dimensional chain structure is produced. The presence of Hg-Cl and Hg-S moieties in the complex lead to the formation weaker intermolecular C-H†¦Cl-Hg , C-H†¦S-Hg interactions between the neighboring 1D chain along b-axis that create a two-dimensional array in the crystal lattice. Scheme 2. Schematic presentation of bisthiophosphoryl ligands 1 (right), 2 (left) Fig. 1 Asymmetric unit of complex 1(right) and 2 (left) are shown Fig.2 Representation of one-dimensional chain of complex 1 along the c-axis. Colour keys for the atoms: Hg †¦., P orange, O red, N blue, C light grey, H light blue Fig. 3 The title complex 1, with displacement ellipsoids drawn at the 50% probability level Fig. 4 The title complex 2, with displacement ellipsoids drawn at the 50% probability level Table 1. Crystal data, data collection and refinement for complexes 1 and 2 Table 2 Selected bond lengths (AÃÅ'Ã…  ) and angles ( °) for complex 1 Table 3 Selected bond lengths (AÃÅ'Ã…  ) and angles ( °) for complex 2

The Wisdom of Frost Exposed in The Oven Bird Essays -- Oven Bird Essay

The Wisdom of Frost Exposed in The Oven Bird  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚         These seemingly negligible birds, symbols of the lyric voice, have intuited the Oven Bird's lesson and are the signs by which one is meant to divine Frost's acceptance of the linguistic implications of the fall from innocence. The Oven Bird, who watching "That other fall we name the fall" come to cover the world with dust, "Knows in singing not to sing." Instead, "The question that he frames in all but words / Is what to make of a diminished thing." The fall, in necessitating both birth and death, imposes a continuum of identity that compromises naming. The process toward death, begun with birth, transmutes and gradually diminishes form, thus adding to the equation - words are things before they become words and things again when they do - an element of inevitable, perpetual senescence. The birds of "A Winter Eden" say "which buds are leaf and which are bloom," but the names are always premature or too late: gold goes to green, dawn to day, everything rises and falls and is tran sformed. Thus the Oven Bird says, "Midsummer is to spring as one to ten," because a season - this or any other - may only be codified analogously. "Fall" takes on a series of identities: petal fall, the fall season, the first and fortunate fall, each of which bears, at the moment of articulation, the burden of a whole complex of moral, aesthetic, and literary valuations. This bird is a "midsummer and a midwood bird" that sees things at the moment of capitulation to the imperatives of fall. Loud, he predicts the inevitable, and his "language" reflects the potential meaninglessness of a world in which one is forced to define a thing by what it departs from or approaches rather than what it "is." To... ... ice are, after all, the inextricable complementarities of one apocalyptic vision: that endlessly regenerative cycle of desire and (self) hatred that necessarily brings the productive poet to scourge his own voice as he mocks both the poetic vocation and the state to which poetry - and if poetry then all language - has come. Frost anticipates modernism's lament and, it may be said, prefigures in his dualism its dubious palliative of self-referential irony. The lyric birds and the weary speakers tell us the genuine Frostian wisdom of achieving a commonsensical accommodation with the fallen world, while inciting at another, and ineffable, level a profound disquiet.    Works Cited Robert Frost and a Poetic of Appetite. Cambridge University Press. 1994 "Robert Frost" in The Columbia History of American Poetry. Ed. Jay Parini. Columbia University Press. 1997