Neutron Stars versus White Dwarfs an Example by

Neutron Stars versus White Dwarfs Neutron stars are extremely dense: they are only 10 kilometers or so in size, but have the mass of an average star (usually about 1.5 times more massive than our Sun). A single [neutron star] can hold the mass of up to 5 suns in a sphere about 12 kilometers across (Krieger 2006). Neutron stars were supergiant stars whose exploded ultradense cores becom[e] neutron stars the size of a small town (Kaler, Jim. Ask Astro. Astronomy, 32, Issue 1. 2004). (This phenomena can also create a black hole.) Need essay sample on "Neutron Stars versus White Dwarfs" topic? We will write a custom essay sample specifically for you Proceed Neutron stars are made of neutrons. Their superdense status is responsible for some of the most exotic phenomenon in the universe, such as pulsars. In 2006, astronomers discovered a densely packed sphere of neutrons spinning so fast that its equator may whirl at 15% the speed of light. The object breaks a 23-year-old record for fastest stellar spin by a sizeable margin (Irion 2006.) Neutron stars have consumed all of their own fuel and so tap into other sources for energy. Thanks to this efficient release of gravitational energy, the temperature at the center of a newborn neutron star can reach 500 billion kelvins Its likely that neutron stars are born magnetized A newborn neutron star is incredibly hot -- it is, after all, the surviving core of a star that has just collapsed and exploded as a supernova. Gravitational energy released during the star's collapse represents almost 10 percent of its rest-mass energy... Rotation offers another energy source for neutron stars. They spin rapidly at birth because the collapsing pre-supernova star "spins up"-- much as a spinning ice skater does when she pulls in her armsSome neutron stars do produce energy by thermonuclear fusion on their surfaces. (Sigg 2005). Both white dwarfs and neutron stars are the remnants of stars about the size of our sun. Neither are sustained via nuclear reactions at the core. The matter in both objects is compressed to extreme densities, and therefore both are useful for studying matter at high energies. White dwarfs are dim; neutron stars are invisible, but they all have masses similar to the sun. Like a neutron star, a white dwarf has no energy source other than what is left over from its birth. White dwarfs are dead stars, and, like neutron stars, are incapable of nuclear reactions. Also like neutron stars, they are incredibly dense. Neutron stars and massive white dwarfs can sometimes, as a result of a close encounter, create an x-ray-emitting binary pair (Morledge, 2002). Both neutron stars and white dwarfs are useful for studying matter at high densities. A typical white dwarf is a little larger than Earth but has 60 percent the mass of the Sun. It forms after a star that is born with less than eight times the Sun's mass expands into a red giant. The red giant eventually casts off its atmosphere, exposing the hot, dense core -- the white dwarf. A white dwarf does not burn nuclear fuel, as the Sun and other stars do; instead, it shines because it is hot. Since white dwarfs no longer generate energy, their evolution resembles the fading fortunes these stars have faced during the 20th century: They start off hot and bright but soon cool and fade (Croswell, 1996.) White dwarfs theoretically turn to black dwarfs, but no such star exists; it takes so long for the process to occur, that all white dwarfs are still evolving. References Ken Croswell, Ken. (1996). White Dwarfs confront the Universe. Astronomy 24, Issue 5. Irion, Robert. (2006). The Speediest Stellar Spinner. Science Now, 2006, Issue 112. Kaler, Jim. (2004). Ask Astro. Astronomy, 32, Issue 1. Krieger, Kim. (2006). Strange Quarks Make for Chunky Stars. Science Now, 2006, Issue 106. Morledge, Paul. (2002). Rocking the Universe. Astronomy, 30, Issue 10. Sigg, Jacob. (2005). Visible Neutron Stars. Astronomy, 33, Issue 3.

Project Vacuum Cleaner Essays

Project Vacuum Cleaner Essays Project Vacuum Cleaner Essay Project Vacuum Cleaner Essay The goal is to build a product that exceeds customers expectations of the current market and ultimately to secure more market share. You are given a fixed duration of 12 months to complete the project. Project Deliverables: 1 Develop a project charter (see the chart template) 2 Develop a project plan (see the project plan template). Complete sections a Section 1: Introduction I Org chart of your team High level was Responsibility matrix iv Resource chart b Section 2: Scope statement only I List your assumptions at a high level c Section 10: Project tracking and control d Other sections are options but highly recommended 3 MS project schedule a Define all relevant activities b Define duration for each task c Define predecessors relationships d Define milestones e Assign resources f Define cost g Identify critical path If possible 4 s-curve a Develop your S Curve using MS Excel b Graph your curve 5 Slide Presentation a You need to do a presentation and explain to the customer what you have done tit the budget and what the customer is getting for that money. Your discussion should revolve around the product not the program management methodology you used. B Make sure you have at least the following 7 slides in your presentation: I Executive summery Project Information at a high level In terms of budget, timeline, scope, resources, methodology items iv Snapshot of your MS project sch edule v Product design and features vi Issues/challenges you faced and how you resolved them vii Snapshot of your S-Curve viii Utilize tables, graphics, diagrams, videos, etc.

Nation States Essay Example | Topics and Well Written Essays - 750 words

Nation States - Essay Example processing immediate and untrammeled power over a contiguous territory occupied, in theory, by a population homogenous in speech, culture, and ethnicity. (p. 2) Simply put, capitalism relies on nation-states to maintain local conditions favourable to a culture of capitalist accumulation as well as to help it navigate the economy. The nation state holds the power which assures the creation and reproduction of the capitalist mode of production through a combination of procedures and processes. Hence, the development of capitalism is largely dependent on the progress of the nation-state and the movements within. Depending on one’s standpoint, the role of nation-state in capitalism is either viewed positively or negatively. For instance, Marxist adherents argue that capitalism was an upshot of the English feudalism and that its evolution resulted to a social malady where the sector responsible for the production of goods is protected by the state, to the disadvantage of the labor and the populace in general. There are varying factors in the development of nation-states. Experiences vary from one country to another. For some, nationhood is achieved due to internal developments while for some; it was realized as a result of some crisis which could be external in nature. In the case of the former, it is attained when a movement has succeeded in mobilizing the masses around one common conception of nationhood; while for the latter, political sovereignty is achieved under extraordinary and short-lived circumstances arising from a regional or global crisis rather than strictly internal developments. (Roshwald p. 2) The existence of nation-states has noble objectives. This is what appeals to people within its territory. Constitutions of countries cite these lofty ideals and while there might be some variations, they all bespeak of one important concept and that is identity. According to Martha Cotham et al., the concept of nationalism is similar to that of social

Global Company and Diversity and the Bottom Line Essay

Global Company and Diversity and the Bottom Line - Essay Example A concept of purpose and a sense of direction strengthen an organization’s ability to survive in changing circumstances and environment. In organizations, large numbers of people congregate under one roof in a joint pursuit of purpose. The organization then sets itself up to harness the creativity of the people for maximum effectiveness. A primary business objective is being profitable, and managers must explain and justify business performance and decisions in light of this objective (Toulmin, Rieke, & Janik, 1984). In this regard, there have been several studies which support that managing diversity in organizations contribute to profitability. diverse business situations will undoubtedly have effects on both the corporate bottom line and on one’s own career prospects†. It is in this regard that this essay is written primarily to evaluate theories and concepts surrounding diversity in organizations in terms of its effect or contribution to the corporate bottom line. Specifically, this paper aims to answer the following questions: (1) what specific aspects make an organization diverse? (2) What value does a diverse, versus a homogenous, organizational culture have to the bottom line? (3) What value does a diverse workforce offer individual workers? And finally, (4) what organizational policies and procedures need to be in place to create and support a diverse workforce? DiTomaso (1999) revealed that there are several factors which influence diversity in organizations, to wit: â€Å"(a) the changing demographic structure of the U.S., (b) the increased importance of globalization to profits and long-term survival in many companies, and (c) changes in the structure of how work gets done†. An organization, being composed of different people should take into account the following diversity attributes: race, ethnicity, gender, class, sexual orientation, physical abilities, age and generation, region, industry, occupation, function,

Smart Corporate Marketing Objectives

Smart Corporate Marketing Objectives Marketing objectives should be based on understanding strengths and weaknesses, and the business environment you operate in. They should also be linked to the overall corporate strategy and So before you start marketing, set some objectives, SMART ones. What do I mean by SMART objectives? Well, its one of those business acronyms taught in all business and marketing qualifications, but unlike many others, this one is actually worth bothering with. Specific Your SMART objectives should be specific, detailed, well defined and results orientated. They should include exactly what has to be achieved and by who. Measurable Objectives are far more effective when they have a measure. For example to increase sales has little effect, but to increase sales by 25% gives you a specific measure to work to. This measure can then be evaluated and used to help form new SMART objectives in the future. Achievable Your SMART objectives must stretch you, but at the same time be achievable. There is no point in setting objectives that you wont be able to achieve for years, as you will soon lose motivation. Realistic Closely linked to achievable, realistic relates more to resources. Do you have the man-power, money, time and opportunity to achieve the SMART objectives? Is there something else that has to happen before you can make a start on that objective Timed Perhaps most importantly set deadlines for achieving your SMART objectives time frames are great at prompting action. It is worth noting that the marketing plan objectives should always lead to actual sales revenue. If not, you need to re-examine your marketing objectives and restate them so that they relate to sales results. In simple words marketing objectives should be: Clear and specific Tangible and measurable Be time-based, with a target achievement date Linking marketing objectives to corporate strategy Your marketing objectives should also be consistent with and indicate the priorities of the organization. This means that objectives should flow from the mission statement of your business, towards the financial objectives and to the rest of the marketing plan. A linked marketing objective could be to add pre-packaged garden soil as a new complementary product line to be offered with plant sales. To grow the business as per the strategic goal and meet the financial objective of 100,000 in extra sales, it has been calculated that a total of 7,500 bags will need to be sold at their selling price of  £100 each. ACTIONS REQUIRED TO ACHIVE MARKETING OBJECTIVES To run a business successfully, today, one must consider the need for publicity, an online presence, direct marketing, advertising, brand identity, word of mouth advertising, networking, viral marketing, pay-per-click advertising, search engine optimization, positioning, market segmentation, html email campaigns, experiential marketing, etc. Many of these activities are phase I functions that need to be considered and begun from day one of marketing. Here are 5 main factors to achieve the marketing objectives: Marketing should be broken into stages. Every marketing activity should be weighted by how well it addresses business objectives, then by investment and how fast it delivers return on investment. Also, the chronology is important. For example, it would be ineffective to run an html email campaign before developing and launching your web site. Time will be in short supply early on. Working with one marketing firm will help to streamline communication, reporting and execution. Start with publicity. If you are able to achieve some quality article placements in key media, you will be able to use that publicity in coming months/years and in other marketing vehicles to build brand awareness and credibility. Set reasonable expectations for response and return on specific marketing activities. Remember that your company is an unknown entity to your marketplace until you are able to begin building brand awareness and identity. This will take time. Dont change course from a marketing plan that isnt broken, simply because youre growing impatient in other aspects of your business. Be realistic about your budget. In business, you might or might not be able to invest in simultaneous, integrated initiatives. Likewise, if your budget needs to be amended, let your marketing team know. They will adjust the plan and schedule to meet that new reality. Detailed Review of plans and programs At this stage, you will need to review your overall marketing objectives into detailed plans and program. Although these detailed plans may cover each of the 7 Ps, the focus will vary, depending upon your organizations specific strategies. A company will focus for the 7 Ps around each of its products. A market or geographically oriented company will concentrate on each market or geographical area. Each will base its plans upon the detailed needs of its customers, and on the strategies chosen to satisfy these needs. These plans therefore are: Clear They should be an unambiguous statement of exactly what is to be done. Quantified The predicted outcome of each activity should be, as far as possible, quantified; so that its performance can be monitored. Focused The temptation to proliferate activities beyond the numbers which can be realistically controlled should be avoided. Realistic They should be achievable. Agreed Those who are to implement them should be committed to them, and agree that they are achievable. The resulting plans should become a working document which will guide the campaigns taking place throughout the organization over the period of the plan Measurement of Marketing objectives Continuous monitoring of performance, against predetermined targets, represents a most important aspect of marketing. However, perhaps even more important is the enforced discipline of a regular formal review. Again, as with forecasts, in many cases the best (most realistic) planning cycle will revolve around a quarterly review. Best of all, at least in terms of the quantifiable aspects of the plans, if not the wealth of backing detail, is probably a quarterly rolling review. Performance analysis The most important elements of marketing performance, which are normally tracked, are: Sales analysis Most organizations track their sales results and marketing .The more sophisticated track them in terms of sales variance the deviation from the target figures which allows a more immediate picture of deviations to become evident. `Micro-analysis, which is a nicely pseudo-scientific term for the normal management process of investigating detailed problems, then investigates the individual elements (individual products, sales territories, customers and so on) which are failing to meet targets. Market share analysis Few organizations track market share though it is often an important metric. Though absolute sales might grow in an expanding market, share of the market can decrease for future sales when the market starts to drop. Where such market share is tracked, there may be a number of aspects which will be followed: overall market share segment share that in the specific, targeted segment relative share -in relation to the market leaders annual fluctuation rate of market share Expense analysis The key ratio to watch in this area is usually the `marketing expense to sales ratio; although this may be broken down into other elements (advertising to sales, sales administration to sales, and so on). Financial analysis The bottom line of marketing activities should at least in theory, be the net profit (for all except non-profit organizations, where the comparable emphasis may be on remaining within budgeted costs).

Creatures On My Mind :: essays research papers

â€Å"Creatures on My Mind† In the short story, â€Å"Creatures on My Mind,† by Ursula Le Guin, there were many different symbols throughout the story. The author talks about a beetle, a sparrow, and a gull to get the reader to understand what she is trying to say.   Ã‚  Ã‚  Ã‚  Ã‚  The character first starts out talking about a experience she had while sitting on her porch. While sitting their she recognized a beetle lying on it’s back twitching and suffering. She thought about ending the beetles life but couldn’t put herself through it. I think the that the beetle represents how human interaction should be looked at. Human interaction should be looked at what’s on the inside not what’s on the surface, and to take feelings into consideration. When the character doesn’t end the life of the beetle he reveals that she respects all living things, even things she can’t stand.   Ã‚  Ã‚  Ã‚  Ã‚  The second experience that the character stumbles upon is a sparrow trapped in a cage. The character finds someone with a key to open the cage and successfully lets the sparrow go. This experience shows us that we will go out of our way to help a helpless, hurting creature, but the way we go about doing it isn’t always the right way. We can relate this experience to how we help the homeless. The way I can relate the sparrow to the homeless is we help the homeless like the sparrow, but we aren’t always happy when we do it.   Ã‚  Ã‚  Ã‚  Ã‚     Ã‚  Ã‚  Ã‚  Ã‚  The third and last experience that is talked about in the story is how the character finds a gull with a broken along side the water. All the character thinks about is if a dog come by and saw the gull sitting there helpless with a broken wing.

Fractures of the Distal Tibia: Minimally Invasive Plate Osteosynthesis

Injury, Int. J. Care Injured (2004) 35, 615—620 Fractures of the distal tibia: minimally invasive plate osteosynthesis D. J. Redfern*, S. U. Syed, S. J. M. Davies Department of Orthopaedics, Frimley Park Hospital NHS Trust, Surrey, UK Accepted 9 September 2003 KEYWORDS Minimally invasive plate osteosynthesis; Plate ? xation; Fracture; Tibia; Metaphysis Summary Unstable fractures of the distal tibia that are not suitable for intramedullary nailing are commonly treated by open reduction and internal ? ation and/or external ? xation, or treated non-operatively. Treatment of these injuries using minimally invasive plate osteosynthesis (MIPO) techniques may minimise soft tissue injury and damage to the vascular integrity of the fracture fragments. We report the results of 20 patients treated by MIPO for closed fractures of the distal tibia. Their mean age was 38. 3 years (range: 17—71 years). Fractures were classi? ed according to the AO system, and intra-articular extension s according to Ruedi and ? Allgower. The mean time to full weight-bearing was 12 weeks (range: 8—20 weeks) and to union was 23 weeks (range: 18—29 weeks), without need for further surgery. There was one malunion, no deep infections and no failures of ? xation. MIPO is an effective treatment for closed, unstable fractures of the distal tibia, avoiding the complications associated with more traditional methods of internal ? xation and/or external ? xation. ? 2003 Elsevier Ltd. All rights reserved. Introduction Unstable fractures of the distal tibia with or without intra-articular fracture extension can present a management dilemma. Traditionally, there have been a variety of methods of management described and high rates of associated complications reported. Non-operative treatment can be technically demanding and may be associated with joint stiffness in up to 40% of cases as well as shortening and rotational malunion in over 30% of cases. 14,20 Traditional operative treatment of such injuries is also *Corresponding author. Present address: 16 By? eld Road, Isleworth, Middlesex TW7 7AF, UK. Tel. : ? 44-(0)20-8847-1370; fax: ? 44-(0)20-8847-1370. E-mail address: david. j. [email  protected] com (D. J. Redfern). associated with a high incidence of complications. Intramedullary nailing remains the gold standard for treatment of most diaphyseal fractures of the tibia. However, although some authors have described good results with intramedullary nailing in the treatment of distal peri-articular tibial fractures, it is generally considered unsuitable for such injuries, due to technical dif? culty and design limitations. 17,20 Traditional open reduction and internal ? ation of such injuries results in extensive soft tissue dissection and periosteal injury and may be associated with high rates of infection, delayed union, and non-union. 5,11,13,18,19,22 Similarly, external ? xation of distal tibial fractures may also be associated with a high incidence of complications, with pin infection and loosening in up to 50% of cases and malunion rates of up to 45%. 20 Minimally invasive plate osteosynthesis (MIPO) may offer biological 002 0–1383/$ — see front matter ? 2003 Elsevier Ltd. All rights reserved. oi:10. 1016/j. injury. 2003. 09. 005 616 D. J. Redfern et al. advantages. MIPO involves minimal soft tissue dissection with preservation of the vascular integrity of the fracture as well as preserving osteogenic fracture haematoma. 3 MIPO techniques have been used successfully in the treatment of distal femoral fractures. 9,10,23 Experience of the application of these techniques to fractures of the distal tibia is less extensive and opinion regarding optimal technique differs. Some authors advocate temporary external ? xation prior to de? itive MIPO and routine ? xation of associated ? bula fractures. 7 Others advocate a more selective approach to the role of external ? xation and ? bular ? xation. 2 Purpose We report our experience with minimally invasive plate osteosynthesis in the treatment of closed, unstable fractures of the distal tibia that are unsuitable for intramedullary nailing. Patients a nd methods We undertook a review of patients treated by MIPO for unstable fractures of the distal tibia in our hospital, between 1998 and 2001. Twenty-two patients were identi? d, of whom 20 had followTable 1 Patient Detailed patient data Age (years) 71 46 20 32 27 26 34 23 26 26 50 59 27 39 54 67 25 24 67 46 Mechanism of injury Fall Fall Football Motorcycle RTA Twisted Motorcycle RTA Rugby injury Rugby injury Football injury Motorcycle RTA Fall Fall Fall Fall Fell from wheelchair Fall Motorcycle RTA Motorcycle RTA Fall Fall Fracture classi? cation AO/R&A 42-A2 42-B1 42-A2 42-A2 42-B1 42-C1 42-B1/grade 42-A1/grade 42-B1 42-B2 42-A1 43-A3/grade 42-A1 42-A1 42-B1 42-A1 43-B1 42-A1 43-B1/grade 43-B1/grade up available. Their mean age was 38. 3 years (range: 17—71 years). There were 18 males and 4 females. The mechanism of injury was: fall (12); motorcycle accident (6); rugby/football injury (4) (see Table 1). Fractures were classi? ed according to the AO system12 and distal intra-articular fracture extension classi? ed according to Ruedi and Allgower18 ? ? (Table 1). All 20 fractures involved the distal onethird of the tibia and in 5 cases the fracture clearly extended distally in to the ankle joint (Ruedi and ? Allgower grade I in 3 cases and grade II in 2 cases). It ? is important to note that although 16/20 of the fractures were classi? d according to the AO system as 42 (diaphyseal), this is somewhat misleading as the ‘essence’ of these fractures was metaphyseal. Within the strict AO system12 de? nition of a metaphyseal fracture of the distal tibia (43), the centre of the fracture must lie within a square of sides equal to the widest metaphyseal distance, and the centre of many of our fractures lay just outside of the ‘metaphys eal square’ (Fig. 1a). The fracture pattern was however predominantly long oblique or long spiral and as such extended well into the distal metaphysis ? extension into the joint (Fig. 1). Indications for use of MIPO technique These included distal diaphyseal, or metaphyseal fractures of the tibia that were considered unsuitable Time to callus (weeks) 8 7 8 8 8 8 10 10 8 8 11 8 12 12 8 8 10 8 10 10 Time to FWB (weeks) 12 13 12 14 8 20 12 12 10 17 9 14 13 12 N/A 12 10 13 10 12 Time to union (weeks) 26 24 20 22 20 20 24 18 28 29 24 26 24 20 24 20 20 22 24 20 Complications 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 I I II I II — Metalwork discomfort — — — — Super? cial infection Metalwork discomfort Metalwork discomfort — — Malunion CRPS (type 1) — — — — — — — R&A: Ruedi and Allgower. ? Fractures of distal tibia 617 Figure 1 (a) AP and lateral radiographs of the distal tibia for case 8 (42-A1, R&A grade 1). (b) AP radiograph (case 8) at 10 weeks post-operatively showing callus formation (A); AP radiograph (case 8) at 18 weeks showing radiological union (B). for intram edullary nailing due to the distal nature of the fracture and/or intra-articular or peri-articular fracture extensions. gical evidence of callus. All patients were followedup for a minimum of 12 months. Operative technique Management protocol Initially, patients were managed in a plaster splint with elevation until de? itive ? xation could be undertaken. Surgery was undertaken on the next available theatre list and only delayed if soft tissue swelling or anaesthetic concerns dictated that this was necessary. Intravenous antibiotics were given at induction of anaesthesia and two doses following surgery. Post-operatively, patients were not routinely splinted unless deemed unlikely to comply with a partial weight-bearing regime. The majority of patients were encouraged to partial weight-bear on the limb (10—15 kg) from the ? rst post-operative day. Early active and passive knee and ankle motion was encouraged. In the majority of cases, patients were discharged from hospital 24 h following surgery. Clinical and radiological review took place at 6—8 weeks to assess for evidence of callus formation. Patients were allowed to proceed to full weight-bearing on the basis of clinical and radiological evaluation but not before there was radioloSurgery was performed with the patient supine on a radiolucent table. Routine preparation and draping of the injured limb was performed. Both indirect and direct techniques of fracture reduction were used depending upon the nature and pattern of the fracture. Reduction techniques employed included the use of manual traction, the AO femoral distracter, the AO articulated fracture distractor, and direct reduction with fracture reduction forceps across the fracture (via two stab incisions). A 2 cm incision was made proximal and distal to the fracture on the medial border of the tibia. An extraperiosteal, subcutaneous tunnel could then be fashioned between these two incisions using blunt dissection. A pre-measured and pre-contoured narrow 4. 5 mm DCP was then positioned in this extra-periosteal subcutaneous tunnel (Fig. 2). Accurate plate contouring and positioning was con? med by ? uoroscopy. The length of plate selected is important and should be as long as is reasonably possible given the particular fracture pattern. As the length of plate is 618 D. J. Redfern et al. Figure 2 Pre-contoured plate insertion with fracture reduction maintained by direct technique. increased, the strength of the ? xation construct is also increased. 21 A cortic al screw (4. 5 mm) was then inserted through a screw hole at one end of the plate via the incisions already made for plate insertion. At this stage, axial fracture alignment was con? rmed before inserting any further screws. Subsequent screws were inserted close to either side of the fracture via stab incisions. Further screws may be used depending upon the characteristics of the fracture. If possible, a lag screw was also inserted across the fracture (via the plate) in order to further reduce the fracture gap and add to the rigidity of the ? xation. However, because the technique employs a bridge plating principle, interfragmentary lag screws were not felt to be obligatory. It is not necessary to place screws through all of the remaining holes in the plate as this does not further increase the strength or rigidity of the ? ation construct4,21 but does require further skin incisions, providing more potential portals of entry for infection (Fig. 1b). The ? bula was not ? xed unless necessary for accurate reconstruction of length such as encountered with some severely comminuted fractures. With fractures extending into the ankle joint, careful attention was paid to restoration of the articular surface cont inuity and 3. 5 mm cortical screws inserted through stab incisions or formal open exposure as required. In only one case was it deemed necessary to ? x the ? ula in order to accurately reconstruct length before proceeding to minimally invasive plating of the tibia. The mean hospital stay was 6 days (range: 2—31 days). The mean time to radiological evidence of callus formation was 9 weeks (range: 7—12 weeks). Sixty percent of patients achieved radiological callus by 8 weeks and all by 3 months (Table 1 and Fig. 2). The mean time to full weight-bearing was 12 weeks (range: 8—20 weeks) and the mean time to union was 23 weeks (range: 18—29 weeks). There were no non-unions and one malunion in whom there was >58 of varus angulation. There were no cases of failure of ? xation. Three soldiers have subsequently had their metalwork removed due to discomfort during training, and have reported no further symptoms. One patient required exchange of a distal screw that was too long and was impinging upon the distal tibia—? bula joint. A further patient developed type I complex regional pain syndrome (CRPS). He required guanethidine blocks to control his pain. There were no deep infections (one super? cial infection which resolved on oral antibiotics). Sixteen of the 20 patients were employed at the time of their injury. Six patients were soldiers. All patients in this study have subsequently returned to their pre-injury occupations/level of activity. Discussion Results Of the 20 patients presented, 12 were operated upon within 24 h of the injury, and 16 within 72 h of the injury. Surgery was delayed in the remaining four patients due to: transfer from another hospital (1); swelling at the site of injury (1); medical problems (1); and for further imaging (1). The surgery was performed by, or supervised by, one of six consultant orthopaedic surgeons in the department. Favourable results have been described using minimally invasive plate osteosynthesis techniques for ? xation of distal femoral fractures. 9,10,23 Cadaveric and animal studies have emphasised the importance of minimising the degree of soft tissue damage in the region of long bone fractures. 3,16,24 Recently, Borrelli et al. 1 have demonstrated that the distal metaphyseal region of the tibia has a relatively rich extraosseous blood supply, provided primarily by Fractures of distal tibia 619 branches of the anterior tibial and posterior tibial arteries. They also demonstrated that open plating in this region produces signi? cantly greater disruption of this extraosseous blood supply than minimally invasive plate application. Helfet et al. 7 described their experience with MIPO in 20 closed pilon fractures and advocated routine use of external ? xation acutely, followed by de? nitive ? xation 5—7 days later once the swelling has subsided. They also advocated the routine ? xation of associated ? bula fractures. They splinted the limb post-operatively but allowed toe-touch weight-bearing (20 lb) from the ? rst post-operative day. Their patients achieved full weight-bearing at an average of 10. 7 weeks (range: 8—16 weeks). Malunion occurred in 20% of cases although all patients had a good functional outcome and none required any further surgery. Collinge et al. 2 have reported their experience using MIPO in 17 tibial shaft fractures. Twelve cases had open injuries and ? ve of these required bone grafting at a later stage such that they suggested that this should be considered at an early stage in such injuries. The ? ve patients with closed injuries had complete union after the index procedure with no cases of malunion or infection. These closed injuries all achieved a good functional outcome. They routinely splinted the limb post-operatively with weightbearing commenced at approximately 12 weeks. In this series, we con? rm that good results can be obtained with this technique in the treatment of closed tibial fractures with intra-articular or periarticular fracture extensions, which are not suitable for intramedullary nailing. However, intramedullary nailing still remains the treatment of choice for most uncomplicated diaphyseal fractures of the tibia. We would not advocate the routine use of external ? ation in the acute management of such injuries, except in some open injuries with extensive soft tissue damage. Early de? nitive surgery negates the need for any form of temporary ? xation other than a POP back-slab for closed fractures. This avoids the added risk of complications arising from the use of such devices. It is our experience that ? xation of the ? bula is not necessary except to aid in reconstructi on of length when there is extensive comminution of the tibial fracture. In the current series (and those of Collinge et al. 2 and Koury et al. ), a 4. 5 mm DCP has been used with satisfactory results. However, this is a relatively bulky implant and lower pro? le plate designs might be expected to result in a lower incidence of postoperative metalwork discomfort along this subcutaneous medial aspect of the tibia, especially in the region of the medial malleolus. This in turn may reduce the need for subsequent implant removal. Other recent developments in plate design include pre-contoured and locking plates (e. g. LCP system, Synthes), which may offer signi? cant advantages. The ‘internal ? ator’ design of locking plates has the advantage that screw insertion does not draw the bony fragments to the plate (as occurs with traditional non-locking plates) and hence, the precise contouring of the plate is less important in achieving accurate fracture reduction. 6,15 For the same reason, the footprint of the locking plates should also be signi? cantly smaller than traditional non-locking plates, hence preserving periosteal blood supply to the fracture. 6 In the majority of cases, we have found it possible to safely mobilise patients, partial weightbearing (10—15 kg), from the ? st post-operative day without external splintage of the limb. This also allows early mobilisation of the knee, ankle and subtalar joints. Conclusion Whilst intramedullary nailing still remains the treatment of choice for most uncomplicated diaphyseal fractures of the tibia, minimally invasive plate osteosynthesis offers a reliable and reproducible technique in the treatment of closed unstable fractures of the distal tibia with intra-articular or periarticular fracture extensions. This technique may avoid the signi? ant complications encountered with more commonly used techniques of internal ? xation and external ? xation in such injuries. References 1. Borrelli J, Prickett W, Song E, Becker D, Ricci W. Extraosseous blood supply of the tibia and the effects of different plating techniques: a human cadaveric study. J Orthop Trauma 2002;16:691—5. 2. Collinge C, Sanders R, DiPasquale T. Treatment of complex tibial periarticular fractures using percutaneous techniques. Clin Orthop 2000;375:69—77. 3. Farouk O, Krettek C, Miclau T, Schandelmaier P, Guy P, Tscherne H. 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