The Bidvest Group Limited is a services, trading, Essays

The Bidvest Group Limited is a services, trading, and distribution company. The Group was founded in 1988 by Brian Joffe and listed on the Johannesburg Stock Exchange in 1990. The Group owns or has significant holdings in over 300 companies. Stock price : BVT (JSE) 15,673.00 ZAC -658.00 (-4.03%) Feb 28, 11:48 AM GMT+2 - Disclaimer CEO : The current CEO is Lindsay Peter Ralphs (May 23, 2016-) Headquarters : Johannesburg, South Africa Founder : Brian Joffe Founded : formed in the year 1988 Number of employees : 117,000 Subsidiaries : BFS Group Ltd , Bidvest Insurance , HYPERLINK "https://www.google.com/search?q=BidAir+Cargostick=H4sIAAAAAAAAAOPgE-LSz9U3SK6yTDEoUgKzsw1y0s0KtTQzyq30k_NzclKTSzLz8_Tzi9IT8zKrEkGcYqvi0qTizJTMxKLM1GIAyQjlGEUAAAAsa=Xved=0ahUKEwjo_dH0xLLSAhXGXhoKHQc6BxUQmxMImgEoAzAU" bidAir Cargo Leadership [ HYPERLINK "https://en.wikipedia.org/w/index.php?title=Bidvest_Groupaction=editsection=2" \o "Edit section: Leadership" edit ] The Bidvest Group Limited board comprises fourteen members: six executive directors, one non-executive director, and seven independent non-executive directors. Directorate Independent non-executive chairman Lorato Phalatse (54) BA Political Science (Hons) University of Leeds UK MA Southern African Studies University of York UK Appointed: Appointed as director on April 20 2012 and as chairman during September 2012 Lorato is a non-executive director of Pick n Pay. Lorato has held various positions over the years including deputy director general in the office of the President and a number of other positions in the FMCG and retail banking sectors. Lorato was CEO and co-founder of Nozala Investments, a woman-led and controlled investment company. In 2016 Lorato was appointed independent non-executive director of Bid Corporation Limited. Group chief executive Lindsay Peter Ralphs (61) CA( SA) Qualification: B.Com, BAcc , CA( SA), Appointed: May 10 1992. Lindsay Ralphs was appointed a Director of the Bidvest Group Limited on May 10 1992. Director of numerous Bidvest subsidiaries, Chairman of the Bidvest South Africa divisions and Chairman of Bidvest Namibia. During his Bidvest career he has been Group Operations Director, Managing Director of Bidvest Steiner and was responsible for forming the Bidvest Services division in 1994. In February 2011, Lindsay was appointed CEO of Bidvest South Africa and in May 2016 was appointed CEO of the Bidvest Group Limited after the unbundling of The Bidvest Food Division. Executive directors Hans Peter Meijer (60) B. Compt , MBL Group financial director Appointed: May 23 2016 Peter joined the Bidvest Corporate office in 1990, then in 1995 moved into a subsidiary divisional financial role as financial director of Steiner, appointed as financial director of the Bidserv Division in 2001, and finally the Bidvest SA Division in 2011. Peter serves on all SA divisional boards and divisional audit committees, and was appointed to the Bidvest Group Board as Group financial director on May 23 2016. Anthony William Dawe (50) CA( SA) Chief executive of Bidvest Freight Appointed: June 28 2006 . Director of numerous Bidvest subsidiaries. Anthony has many years' experience in the freight industry with most of those years focused in the South African port environment. Prior to this, Anthony's finance experience was in London and for one of the large accounting firms in South Africa. Nompumelelo ( Mpumi ) Themekile Madisa (37) B.Comm (Hons) Economics and BSc. Economics and Mathematics, MM in Finance and Investment Masters in Finance and Investment Executive director Appointed: December 4 2013 . Mpumi was previously chief director in the Gauteng provincial government. During her ten years in the Bidvest Group, she has held various senior management and executive board director positions such as general manager business development, divisional director business development, corporate affairs director and sales and marketing director. Director of numerous Bidvest subsidiaries. Executive directors Brian Joffe | Group chief executive Age: 68 Qualification: CA(SA) Appointed: March 1 1989 Bernard Larry Berson | Chief executive, Bidvest Foodservices Age: 50 Qualification: Australian CA Appointed: October 27 2003 David Edward Cleasby | Group financial director Age: 53 Qualification: CA(SA) Appointed: July 9 2007 Anthony William Dawe | Chief executive, Bidvest Freight Age: 49 Qualification: CA(SA) Appointed: June 28 2006 Nompumelelo ( Mpumi ) Madisa | Executive director, Bidvest South Africa Age: 36 Qualification: BComm (Hons) Economics and BSc Economics and Mathematics, MM in Finance and Investment Appointed: December 4 2013 Gillian Claire McMahon | Executive director, Bidvest South Africa Age: 43 Qualification: BCom Hons Business Economics and Industrial Psychology, MCom Industrial Psychology Appointed: May 27 2015 Lindsay Peter Ralphs | Chief executive, Bidvest

Ocean Noise Pollution Essay Example

Ocean Noise Pollution Essay Example Ocean Noise Pollution Paper Ocean Noise Pollution Paper For millions of years, the oceans have been filled with sounds from natural sources such as the squeaks, moans and clicks of whales and dolphins, the snapping of shrimp, the sound caused by wind upon the surface and even the occasional rumble from earthquakes. Over millions of years, the oceans marine species have developed into what they are today, with their own specialized acute hearing abilities, communication skills and echo location abilities at natural sound levels. Hearing is generally as important to many marine creatures as sight is for humans. The oceans once referred to as the The Silent World by Jacques Southeast, has now become an increasingly noisy place since the industrial age. According to Wisped, Noise Pollution is excessive, displeasing human, animal or machine-created environmental noise that disrupts the activity or balance of human or animal life. Noise pollution could also be defined as a type of energy pollution in which distracting, irritating, or damaging sounds are freely audible. As with other forms of energy pollution (such as heat and light pollution), noise pollution contaminants are not physical particles, but rather waves that interfere with durably-occurring waves of a similar type in the same environment. Thus, the definition of noise pollution is open to debate, and there is no clear border as to which sounds may constitute noise pollution. In the narrowest sense, sounds are considered noise pollution if they adversely affect wildlife, human activity, or are capable of damaging physical structures on a regular, repeating basis. Hearing is the universal alerting sense in all vertebrates. Sound is extremely important because animals are able to hear events all around them, no matter where their attention is focused. Sound travels far greater distances than light under water. Light travels only a few hundred meters in the ocean before it is absorbed or scattered. Even where light is available, it is more difficult to see as far under water as in air, limiting vision in the marine environment It is similar to looking through fog on land. So, the best opportunity for long-range vision underwater especially in murky water is to swim beneath objects and see their silhouettes. In consequence, most marine animals rely on sound for survival and depend on unique adaptations hat enable them to communicate, protect themselves, locate food, and navigate underwater. Animals change the rate of sound production and the structure of the sounds to send different messages. Underwater sound allows marine animals to gather information and communicate at great distances and from all directions. The speed of sound determines the delay between when a sound is made and when it is heard. The speed of underwater sound is five times faster than sounds traveling in air. Sound travels much further underwater than in air. Thus marine animals can perceive sound coming from such further distances than terrestrial animals. Because the sound travels faster, they also receive the sounds after much shorter delays (for the same distance). It is no surprise that marine mammals have evolved many different uses for sounds. Marine mammals, such as whales, use sound to identify objects such as food, obstacles, and other whales. By emitting clicks, or short pulses of sound, marine mammals can listen for echoes and detect prey items, or navigate around objects. This animal sense functions just like the sonar systems on navy ships. It is clear that producing and hearing sound is ITIL to marine mammal survival. Whales and dolphins are celebrated for their sounds, but many species of fish and marine invertebrates also use sound. Fish produce various sounds, including grunt, croaks, clicks, and snaps, which are used to attract mates as well as ward off predators. For the taffies, sound production is very important in courtship rituals. Sound is produced by the male taffies to attract the female for mating and is especially important in the murky waters that taffies inhabit where sight is limited. Ashes also produce sound when feeding. When a fish eats hard food, such as coral, it will produce a sound. Fishes sometimes gnash their teeth without the presence of food, which may be a way to scare away predators. As you can see, sound is very important to its underwater inhabitants. It allows them to navigate, to hear approaching predators and prey, and is a way of communicating with other members of the same species. There are a lot of sources of noise in the marine environment. Naturally occurring noises include underwater volcanic eruptions and storms. Background noise in the ocean is produced by reeking waves, wind and rain, and by the huge number of small crustaceans and other animals. A typical background noise level is about 100 decibels (db), which is about the same in energy terms as 40 db in air. Wind and waves in storms, and choruses from fish and invertebrate can increase this level to about 1 20 db. Measurements show that the Pacific Ocean is still relatively quiet and that most of its background noise is produced by wind and by marine creatures. This is in contrast to the Atlantic Ocean, where most of the background noise is from the churning propellers of ocean-going ships. There are also several man-made (anthropogenic) sources of ocean noise, some of which are the unintended by products of human activity (e. G. Sell propulsion), while others are produced for a specific purpose (e. G. Military sonar). Whales, dolphins and porpoises today face a wealth of man-made threats including hunting, ship strikes, entanglement in fishing gear and issues arising from climate change. However, one man-made threat that is not as commonly acknowledged as others is ocean noise pollution. This is partly due to the fact that it is not a visible threat, so can be easily overlooked. The noi se becomes problematic and highly hazardous when it is man-made. In the past several years many studies have shown that man-made ocean noise emanating from such sources as are military sonar equipment, ship traffic, and underwater drilling, commercial shipping seismic surveys for Oil and gas exploration, mineral and aggregate extraction, construction (e. G. Drilling, dredging and explosions), acoustic deterrent and harassment devices(e. G. Pincers on fishing nets used to deter predators) and recreational activities(e. G. Boating). Noise pollution in the oceans has been shown to cause hysterical and behavioral changes in marine life, especially in dolphins and whales, which rely on sound for daily activities. However, low frequency sound produced by large scale, offshore activities is also suspected to have the capacity to cause harm to other marine life as well. It can also cause hemorrhage or other trauma to the marine mammals auditory system, sometimes leading to permanent hearing loss, and, indirectly, death. It also causes displacement from their natural habitat, disruption of feeding, breeding, nursing, and other behaviors vital to the species survival. Some of he sounds produced by these man-made sources can travel for hundreds of kilometers in marine environment, potentially affecting many marine animals over a huge are. The growing amount of human noise pollution in the ocean could lead fish away from good habitat and off to their death, according to new research from a KICK-led team working on the Great Barrier Reef. Noise pollution might also severely affect the distribution offish, and their ability to reproduce, communicate and avoid predators. For example, some studies have reported that Atlantic herring, cod and blue-fin tuna flee sounds and school less coherently in noisy environments. That could mean that fish distributions are being affected, as fish avoid places polluted by man-made noise. Not only can squids and octopuses sense sound, but as it turns out, these and other so-called asphodels might be harmed by growing noise pollution in our oceans?from sources such as offshore drilling, ship motors, sonar use and pile driving. Giant squid, for example, were found along the shores of Austria, Spain in 2001 and 2003 following the use of air guns by offshore vessels and examinations eliminated all known causes of lesions in Hess species, suggesting that the squid deaths could be related to excessive sound exposure. The effects of noise pollution on whales depend, among other things, on the distance the whales are from the source of the noise. If the sound is very powerful and close to the animals it could well bring about permanent ear damage, internal injuries, and even death. Even sounds less powerful can induce temporary deafness, as was shown by studies carried out on seals, dolphins and belugas in captivity. Knowing just how dependent whales are on sounds, there is much cause for concern. During March of 000, at least 17 whales stranded themselves in the Bahamas and the population of beaked whales in this region disappeared. A federal investigation identified testing of a U. S. Ana active sonar system as the cause. There are many things we can do to decrease ocean noise, Ocean Link, an organization dedicated to ocean education, says on its website. The first would be to simply recognize that there is a noise problem in the oceans, which some governments have begun to do. With formal recognition, it may be possible for national and international agencies to work together to help reduce this problem. For any new policies regarding ocean noise, scientists should follow the precautionary principal to ensure that no further harm will come to marine mammals. From this perspective, governments should adopt legislation with the habitats of marine mammals in mind, ensuring that important areas would receive the least impact possible. While these may come too late for hundreds of sea animals that have already been damaged by underwater noise, with the right and concerted action, the seas may resonate with the sounds of whale songs, not the human-produced lethal noises of engines and machinery.

Causes of school Violence Essay Example | Topics and Well Written Essays - 750 words

Causes of school Violence - Essay Example In this paper, I am going to argue that domestic abuse, anger, overcrowded schools, medical problems, and gang activities cause school violence. First, school violence is caused by domestic violence. This is because the students who face a lot of domestic violence at home become violent too. Domestic violence include insults and physical violence. The students who face this problem at home become violent and therefore become dangerous at school. Students who are abused at home carry this violent attitude to their school and start molesting the other students (â€Å"School Violence† web). Such students accept domestic violence as a way of life and thus they see it as normal to molest fellow students in school. The schools that have many students are likely to have more violence. Overcrowded schools especially the schools that are in low income areas report many cases of school violence. We can argue that overcrowding in schools makes it difficult for teachers and school management to control students. Therefore, the students get the chance to molest and beat other students since it is difficult to catch them (â€Å"Constitutional Rights Foundation† web). Maintaining discipline in overcrowded schools is also difficult and thus, many students will have discipline issues which results to school violence. It is also true that overcrowded schools get students from poor and low income families. It is claimed that â€Å"Race and ethnicity, income levels, and other measurable elements have often been singled out by public heath experts as risk factors that can contribute to anti-social behavior, from smoking and drinking to violent behavior and suicide† (â€Å"Constitutional Rights Foundation† web). For example, children from low income families and slums attend overcrowded schools. Since there is a lot of violence in low income families and slum neighborhoods, students coming from these neighborhoods bring violence

Corporate Culture and Performance Essay Example | Topics and Well Written Essays - 500 words

Corporate Culture and Performance - Essay Example While organizational values relate to employees, profit, customers, stakeholders, community, and the like, individual goals will relate to fairness, honesty, trust, respect, quality, and cooperation. These are precisely the values that are inherent in the organizational values statement. Alone, these organizational values are far too general and open to interpretation. It is easy to forget the particular and complicated nature of human moral experience (Kotter, 2003). Thinking about and discussing the ethical implications of a goal is more practical and valuable than using a list of values or ethical models. Acting on the ethical implications is even more valuable. Ethical action in modern organizations is the relentless effort to make values a part of the goal-setting equation. Where the managers go wrong, however, is in expecting more from these values than they can deliver. it s organizational culture reflects unique industry requirements and customers' expectations. Each application deals with the realities of a particular goal and how to accomplish it. It is possible to say that new changes will be influenced by old principles of work and will need a new set of principles for further change. In this case, corporate culture is the real foundation on which organizational ethics is built.

Cell Membrane Structure Phospholipid Bilayer

Cell Membrane Structure Phospholipid Bilayer A cell is the basic unit of life, and the cell membrane is an important structure present in all cells, irrespective of whether they are plant cells or animal cells. This structure is a vital component of any cell and it has a variety of important functions. Cell membrane functions include maintaining the boundaries of the cells, thus supporting the contents of the cell, maintaining proper cell to cell contact, regulating the entry and exit of molecules in and out of the cell, etc. Thus, to understand how the cell membrane manages to carry out this procedure, one needs to understand the cell membrane structure. Given below are the various components that comprise the structure of the cell membrane according to the Fluid Mosaic model. The first layer of cell membrane consists of a phosphid bilayer. The phosphate molecules are arranged in such a way that the hydrophilic heads are on the outside, while the hydrophobic fatty acid tails are on the inside, facing each other. The tails of the molecule are said to be hydrophobic and that is why they points inwardly towards each other. This specific arrangement of the lipid bilayer is for the purpose of preventing the entry of polar solutes, like amino acids, proteins, carbohydrates, etc. Thus, the phosphate lipid bilayer is one of the main factors responsible for regulating the entry and exit of molecules in and out of the cell. Integral Membrane Proteins Integral membrane proteins are those proteins that are a part of the cell membrane structure. They are present between consecutive molecules of phopholipids. These fibrous proteins present may span the entire length of the cell membrane. These molecules have important functions, as they serve as receptors for the cell. Some of the proteins of the cell membrane may also enter the cell. Sometimes, a part of the protein molecule is inside and some of it is outside. These kind of protein molecules act as carriers for active transport of substances in and out of the cell. Some of these protein molecules form pores and thus, allow fatty acids and other lipid insoluble in water molecules to pass through. Furthermore, other integral proteins serve as channel proteins as well to aid in selective transport of ions in and out of the cell. Such molecules are visible with the help of an electron microscopy. Other Elements Certain other elements may also be present along the length of the cell membrane, depending on the location and needs of the cell. These structures include globular proteins, which are peripherally placed and are only at times associated with the cell. These protein molecules may even be enzymes or glycoproteins. In such cases, either the cell will have special functions, or the location of the cell may require it to perform certain specific functions. When speaking of plant cell vs animal cell, there is one important structure that is additionally present most of the time in animal cells. These molecules are cholesterol molecules, which aid the phospholipids in making the membrane impermeable to water soluble substances. These cholesterol molecules also stabilize the membrane and provide the cell with a cushion effect, which prevents it from suffering any major injuries due to trauma and impact forces. Cell Membrane Function Cell membrane is the outer covering of a cell, which keep the ingredients of a cell intact. Apart from that, there are various other functions, that are carried out by this structure. Read on It is a common fact that cells are the fundamental building blocks of life. These structures form the basic structural and functional unit of any living thing. While some organisms, like, bacteria are single-celled, most other living things are multicellular. In case of multicellular organisms like humans (an adult human has around 100 trillion cells in the body), there are various types of cells, which are assigned different functions. Each cell is made of intricate structures, which forms an interconnected network, which strives to carry out the function of that cell. As the nature of the function of the cells differ, the functions of various parts of the cells too differ. Let us take a look at the various parts of a cell, especially, the cell membrane and cell membrane function. Cell Membrane and Other Parts of a Cell Basically there are two types of cells eukaryotic and prokaryotic. While plants, animals, fungi, protozoans, etc. possess eukaryotic cells, prokaryotic cells are found in bacteria only. The difference between the two types of cells lie in the fact that prokaryotic cells do not have nucleus (and/or some other organelles) and are comparatively smaller, as compared to eukaryotic ones. As far as eukaryotic cells are concerned, the basic structure includes parts like DNA, ribosomes, vesicle, endoplasmic reticulum (both rough and smooth), Golgi apparatus, cytoskeleton, mitochondria, vacuole, centrioles, lysosome, cytoplasm, plasma membrane and cell wall. While plant cells have a large vacuole and a definite cell wall, animal cells lack cell wall but some may have very small vacuoles. Animal cells do not have chloroplasts too. This article is about cell membrane, which is also known as plasma membrane or plasmalemma. Scroll down for information about cell membrane function. Read more on: Similarities Between Eukaryotic and Prokaryotic Cells Plant Cell vs Animal Cell Plant Cell Organelles What is a Cell Membrane? Cell membrane or plasma membrane is one of the vital parts of a cell that encloses and protects the constituents of a cell. It separates the interior of a cell from outside environment. It is like a covering that encloses the different organelles of the cell and the fluid that harbors these organelles. To be precise, cell membrane physically separates the contents of the cell from the outside environment, but, in plants, fungi and some bacteria, there is a cell wall that surrounds the cell membrane. However, the cell wall acts as a solid mechanical support only. The actual function of cell membrane is the same in both cases and it is not much altered by the mere presence of a cell wall. The cell membrane is made of two layers of phospholipids and each phospholipid molecule has a head and a tail region. The head region is called hydrophilic (attraction towards water molecules) and the tail ends are known as hydrophobic (repels water molecules). Both layers of phospholipids are arrange d so that the head regions form the outer and inner surface of the cell membrane and the tail ends come close in the center of the cell membrane. Other than phospholipids, cell membrane contains lots of protein molecules, which are embedded in the phospholipid layer. All these constituents of the cell membrane work jointly to carry out its function. The following paragraph deals with cell membrane function. Read more on cell nucleus: structure and functions and cytoplasm function in a cell. What is the Function of the Cell Membrane? As mentioned above, one of the basic functions of a cell membrane is to act like a protective outer covering for the cell. Apart from this, there are many other important cell membrane functions, that are vital for the functioning of the cell. The following are some of the cell membrane functions. Cell membrane anchors the cytoskeleton (a cellular skeleton made of protein and contained in the cytoplasm) and gives shape to the cell. Cell membrane is responsible for attaching the cell to the extracellular matrix (non living material that is found outside the cells), so that the cells group together to form tissues. Another important cell membrane function is the transportation of materials needed for the functioning of the cell organelles. Cell membrane is semi permeable and controls the in and out movements of substances. Such movement of substances may be either at the expense of cellular energy or passive, without using cellular energy. The protein molecules in the cell membrane receive signals from other cells or the outside environment and convert the signals to messages, that are passed to the organelles inside the cell. In some cells, the protein molecules in the cell membrane group together to form enzymes, which carry out metabolic reactions near the inner surface of the cell membrane. Read more on how do enzymes work. The proteins in the cell membrane also help very small molecules to get themselves transported through the cell membrane, provided, the molecules are traveling from a region with lots of molecules to a region with less number of molecules. Biological Membranes and the Cell Surface http://www.uic.edu/classes/bios/bios100/f06pm/plasmamemb.jpg Membrane Functions Form specialized compartments by selective permeability Unique environment Creation of concentration gradients pH and charge (electrical, ionic) differences Asymmetric protein distribution Cell-Cell recognition Site for receptor molecule biding for cell signaling Receptor binds ligand (such as a hormone) Induces intracellular reactions Controls and regulates reaction sequences Product of one enzyme is the substrate for the next enzyme Can line up the enzymes in the proper sequence Membrane Structure According to the Fluid Mosaic Model of Singer and Nicolson http://www.uic.edu/classes/bios/bios100/f06pm/fmm.jpg The membrane is a fluid mosaic of phospholipids and proteins Two main categories of membrane proteins integral and peripheral Peripheral proteins bound to the surface of the membrane Integral proteins permeate the surface of the membrane Membrane regions differ in protein configuration and concentration Outside vs. inside different peripheral proteins Proteins only exposed to one surface Proteins extend completely through exposed to both surfaces Membrane lipid layer fluid Proteins move laterally along membrane Membrane Lipids Phospholipids most abundant Phosphate may have additional polar groups such as choline, ethanolamine, serine, inositol These increase hydrophilicity Cholesterol a steroid Can comprise up to 50% of animal plasma membrane Hydrophilic OH groups toward surface Smaller than a phospholipid and less amphipathic (having both polar and non-polar regions of the molecule) Other molecules include ceramides and sphingolipds amino alcohols with fatty acid chains These lipids distributed asymmetrically Bilayer Formation Membrane components are Amphipathic (having both polar and non-polar regions of the molecule) Spontaneously form bilayers Hydrophilic portions face water sides Hydrophobic core Never have a free end due to cohesion Spontaneously reseal Fuse Liposome Circular bilayer surrounding water compartment Can form naturally or artificially Can be used to deliver drugs and DNA to cells Membrane Fluidity Membrane is Fluid Lipids have rapid lateral movement Lipids flip-flop extremely slowly Lipids asymmetrically distributed in membrane Different lipids in each side of bilayer Fluidity depends on lipid composition Saturated fatty acids All C-C bonds are single bonds Straight chain allows maximum interaction of fatty acid tails Make membrane less fliuid Solid at room temperature Bad Fats that clog arteries (animal fats) Unsaturated fatty acids Some C=C bond (double bonds) Bent chain keeping tails apart Make membrane more fluid Polyunsaturated fats have multiple double bonds and bends Liquid at room temperature Good Fats which do not clog arteries (vegetable fats) Cholesterol Reduces membrane fluidity by reducing phospholipid movement Hinders solidification at low (room) temperatures How Cells Regulate Membrane Fluidity Desaturate fatty acids Produce more unsaturated fatty acids Change tail length (the longer the tail, the less fluid the membrane) Membrane Carbohydrates Glycolipids and Glycoproteins Face away from cytoplasm (on outside of cell) Attached to protein or lipid Blood antigens Determine blood type bound to lipids (glycolipids) Glycoproteins Protein Receptors Provide specificity for cell-cell or cell-protein interactions (see below) Membrane Proteins Peripheral Proteins completely on membrane surface ionic and H-bond interactions with hydrophilic lipid and protein groups can be removed with high salt or alkaline Integral Proteins Possess hydrophobic domains which are anchored to hydrophobic lipids alpha helix more complex structure An Example Asymetry of Intestinal Epithelial Cell Membranes Apical surface selectively absorbs materials Contains specific transport proteins Lateral surface interacts with neighboring cells Contains junction proteins to allow cellular communication Basal surface sticks to extracellular matrix and exchanges with blood Contains proteins for anchoring The Extracellular Matrix (ECM) and Plant Cell Walls In animal cells, the ECM is a mish-mash of proteins (usually collagen) and gel-forming polysaccharides The ECM is connected to the cytoskeletin via Integrins and Fibronectins Plant Primary Cell Walls for a rigid cross-linked network of cellulose fibers and pectin a fiber composite Fiber composites resist tension and compression Plant Secondary Cell Walls are further strengthened w/ Lignin Secondary Cell Walls is basically what comprises wood Cell to Cell Attachments Tight Junctions and Desmosomes Tight Junctions are specialized proteins in the plasma membranes of adjacent animal cells they stitch together adjacent cells form a watertight cell Desmosomes are specialized connection protein complexes in animal cells they rivet cells together they are attached to the intermediate fibers of adjacent cells Cell Gaps Plasmodesmata Gap Junctions In plant cells, Plasmodesmata are gaps in the cell wall create direct connections between adjacent cells May contain proteins which regulate cell to cell exchange form a continuous cytoplasmic connection between cells called the symplast In animal cells, Gap Junctions are holes lined with specialized proteins allow cell-cell communication (this is what coordinates your heartbeat) Cell Communication In multi-cellular organism, cells can communicate via chemical messenger Three Stages of Cellular Communication Reception A chemical message (ligand) binds to a protein on the cell surfaceÂÂ   Transduction The binding of the signal molecule alters the receptor protein in some way. The signal usually starts a cascade of reactions known as a signal transduction pathway Response The transduction pathway finally triggers a response The responses can vary from turning on a gene, activating an enzyme, rearranging the cytoskeleton There is usually an amplification of the signal (one hormone can elicit the response of over 108 molecules No matter where they are located, signal receptors have several general characteristics signal receptors are specific to cell types (i.e. you wont find insulin receptors on bone cells) receptors are dynamic the number of receptors on a cell surface is variable the ability of a molecule to bind to the receptor is not fixed (i.e. it may decline w/ intense stimulation) receptors can be blocked Two Methods of Cell-Cell Communication Steroid Hormones can enter directly into a cell bind to receptors in the cytosol hormone-receptor complex binds to DNA, inducing change testosterone, estrogen, progesterone are examples of steroid hormones Signal Transduction conversion of signals from one form to another Very complicated pathways all are different! G Protein receptors G-proteins are called as such because they have GTP bound to them Receptors have inactive G-proteins associated with them When the signal binds to the receptor, the G-protein changes shape and becomes active (into the on configuration) The active G-protein binds to an enzyme which produces a secondary message Frequently, second messengers activate other messengers, creating a cascade G-protein signal transduction sequences are extremely common in animal systems embryonic development human vision and smell over 60% of all medications used today exert their effects by influencing G-protein pathways Tyrosine-Kinase Receptors Another Example of a Signal Transduction Pathway Tyrosine-Kinase Receptors often have a structure similar to the diagram below: http://www.uic.edu/classes/bios/bios100/f06pm/tyro-kin02.jpg Part of the receptor on the cytoplasmic side serves as an enzyme which catalyzes the transfer of phosphate groups from ATP to the amino acid Tyrosine on a substrate protein The activation of a Tyrosine-Kinase Receptor occurs as follows: Two signal molecule binds to two nearby Tyrosine-Kinase Receptors, causing them to aggregate, forming a dimer The formation of a dimer activated the Tyrosine-Kinase portion of each polypeptide The activated Tyrosine-Kinases phosphorylate the Tyrosine residues on the protein The activated receptor protein is now recognized by specific relay proteins They bind to the phosphorylated tyrosines, which cause, you guessed it, a conformation change. The activated relay protein can then trigger a cellular response One activated Tyrosine-Kinase dimer can activate over ten different relay proteins, each which triggers a different response The ability of one ligand binding event to elicit so many response pathways is a key difference between these receptors and G-protein-linked receptors (that, and the absence of G- proteins of course) Abnormal Tyrosine-Kinases that aggregate without the binding of a ligand have been linked with some forms of cancer Signal Transduction Shutdown Most signal-transduction/hormone systems are designed to shut down rapidly Enzymes called phosphatases remove the phosphate groups from secondary messengers in the cascade This will shut down the signal transduction pathway at least until another signal is received

Analysis of “Time Talks, with an Accent” by Robert Levine

In the article, â€Å"Time Talks, with an Accent', author Robert Levine explores a cross cultural contrasts in the idea of time, called ‘social time'. He discovers that this concept includes the components of waiting, rushing; being early or late; as well as the past, present and future. He chose to be a professor of social psychology so that he could manage his own time. While teaching in Brazil, he discovers the concept of amanha, which signifies that everything that can be postponed, should be.He observes that not one clock in the city of Niteroi is accurate and students arriving to his class are casual about when class began and ended, which contrasts with how Americans relate to time. Levine has numerous mishaps with amanha during his stay. When he consults his department chair about the issue, she arrives late for their appointment. His students come and go to appointments without reason. Levine then tries to use what he has learned about amanha when his landlord runs la te. Levine runs an errand and misses the appointment and angers the landlord for keeping him waiting.Levine concludes that the understanding of time concepts are a part of larger, cultural values. He outlines the work of Edward Hall, a social anthropologist whose work focused on what he called the †the silent language† (30) of time, which is unspoken, yet easily learned by children. Understanding this silent language is vital for the success of a foreigner living abroad. Since his time in Brazil, Levine has focused on the concept of punctuality and its effects on the health of people and society. He has found great diversity in the concept of time, among cultures and within countries.

Ethical Problems associated to Information Technology Essay

Information technology has been continuously booming with new technological products that create a more diverse information environment. There have been dramatic changes associated with the IT, and these changes create ethical problems and upheavals that usually have something to do with ethics. True, there has been technological development in the arena—one that occurs â€Å"when either the technological paradigm is elaborated in terms of improved concepts, theories, and methods, or in instances of the paradigm are improved† (Moor, 2008, p. 27), such as in terms of efficiency, effectiveness, and safety. This creates an enormous social impact, and it has led to a technological revolution that considerably takes time and is difficult to predict. Information technology has gone over the introduction stage and the permeation stage. We are on the power stage wherein the technology is readily available, affecting people directly and indirectly. This creates an impact that is superbly enormous; yet, there are always the ethical problems that springs forth in the arena. Ethical problems that surround the self-identity, anonymity, and privacy of a person are always attached when it comes to IT. The technological revolution has a large-scale effect that transforms the society, while affecting the manner in which the society functions (Moor, 2008, p. 29). It is evident that open technological revolutions in open societies still need some enhancements, so that the ethical problems would be controlled and maximized. Main Body There are a number of important issues that surround the technological paradigm of IT, especially in relation to ethics. Some of these are in the form of self-identity, anonymity, as well as privacy. There are also other unethical issues (e. g. , cheating, hacking, wardriving) that are attached to the technological paradigm of IT. Ethical problems in self-identity The self-identity is being constructed according to how the individual interacts with the society and with himself or herself. In the social landscape of modernity, there are numerous major changes in the external social environment that affects the individual during this social transformation. In the age of the IT, people get to have the capacity to reconstruct the universe through the everyday realities and circumstances that take place in their specific worlds. It is a continuous state of affairs that largely creates the self-identity and the personal feelings attached to this paradigm. This new sense of identity are being formed with the intrusion of the IT in a person’s life, and people get to have personal relationship even with people who are unknown to them—people who suddenly pop out in their computer’s screens, with names that may or may not be factual. Personal relationships help form the self-identity, offering opportunities for self-expression and the self-renewal. According to Giddens (1991), The modern world is a ‘runaway world’: not only is the pace of social change much faster than in any prior system, so also is its scope, and the profoundness with which it affects pre-existing social practices and modes of behavior. (Giddens, 1991, p. 16) With this, it is apparent that the IT becomes an active component in the continuous transformation of a person’s identity, as it creates and affects the social practices and the modes of a person’s behavior. Thus, problems that affect the personal life of the individual could affect not only the self-identity, but the social practices and the environment as a whole. Ethical problems in terms of anonymity and privacy, for example, can lead to an identity that is blemished because of unethical conduct. Despite the fact that people always carry discursive interpretations of their behavior, this practical consciousness drives the person into creating or destroying the ontological security of human activity in a culture. As an effect, people tend to write comments anonymously while hiding their true identities. Ethical problems in anonymity According to the article that Richard Perez-Pena (2010) wrote entitled ‘News Sites Rethink Anonymous Online Comments’, it says that Internet users usually make use of the digital disguise, revealing their power and their sentiments without acknowledging their true identities to the viewers. This constitutes a sort of freedom for the digital users, and this is most typical in news sites, wherein the viewers are allowed to post comments without indicating their true identities, keeping their privacy in a world that is being presented in public. As indicated in the article, â€Å"Anyone could weigh in and remain anonymous† (Perez-Pena, 2010, p. 1), and this leads to the question on whether or not viewers of Internet sites should be allowed to remain anonymous when dictating their comments and suggestions. This is a very significant ethical problem associated to IT, since it has been ethically accepted that any type of idea or sentiment should be associated to the respectful person who has formed the idea. According to Arianna Huffington, founder of The Huffington Post, Anonymity is just the way things are done. It’s an accepted part of the Internet, but there’s no question that people hide behind anonymity to make vile or controversial comments. (Perez-Pena, 2010, p. 1) It has, therefore, been advised that viewers should indicate their factual names, especially when making a significant commentary about the society. They should use their real names, and this may be done by requiring people to register first before posting their commentaries. Ethical problems in privacy According to the article that Scott Rosenberg (2010) wrote entitled ‘Online Comments Need Moderation, Not Real Names’, there is also the statement that defines how newspaper website managers have been reacting in terms of anonymity and privacy keeping. As stated, â€Å"If only they could make people sign their real names, surely the atmosphere would improve† (Rosenberg, 2010, p. 1). Online conversation spaces make media outlets turn the common software on and then leave them as it is, as if the discussions would â€Å"magically take care of themselves† (Rosenberg, 2010, p. 1). The problem, however, is that the commenters should not be faceless and should carry identities that are open for the other viewers. This problem is in the identity system, with the Web having no identity system that would ethically reconnect the idea to the person who has declared it. As stated in the article, The Web has no identity system, and though the FBI can track you down if the provocation is dire enough, and if you get editors mad enough they can track you down, too, most media companies aren’t going to waste the time and money. (Rosenberg, 2010, p. 1) Ethical privacy problems can also be in the form of ‘hacking’ or â€Å"using unauthorized access to an information system† (Floridi, 2008, p. 43). This indulges privacy and confidentiality. Conclusion There are other ethical problems associated with the IT of the modern social world, such as using the new technology in order to cheat one’s taxes, or deviating the user from his or her true name or identity. It can also be in the form of wardriving wherein people try to connect wirelessly to other people’s networks (Moor, 2008, p. 33). All these unethical conducts can create an enormous social impact that leads to technological revolution that can contract IT in its power stage. With proper management, it can develop the IT into something that is more powerful and enormous, without the ethical problems that have large-scale effects on the society. It is evident, therefore, that open societies through the IT still need some enhancements, so that the ethical problems would be controlled and maximized. References Floridi, L. (2008). Information ethics: its nature and scope. In Eds. Jeroen van den Hoven and John Weckert’s Information technology and moral philosophy. New York, NY: Cambridge University Press. Giddens, A. (1991). Modernity and self-identity: self and society in the late modern age. Stanford, CA: Stanford University Press. Moor, J. (2008). Why we need better ethics for emerging technologies. In Eds. Jeroen van den Hoven and John Weckert’s Information technology and moral philosophy. New York, NY: Cambridge University Press. Perez-Pena, R. (2010, April 11). News sites rethink anonymous online comments. Retrieved May 7, 2010, from The New York Times Company database: http://www. nytimes. com/2010/04/12/technology/12comments. html. Rosenberg, S. (2010, April 13). Online comments need moderation, not real names. Retrieved May 7, 2010, from Salon Media Group, Inc. database: http://www. salon. com/news/feature/2010/04/13/newspaper_online_comments_moderation_open2010.