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سه شنبه 6 ارديبهشت 1390برچسب:, :: 19:9 ::  نويسنده : فردین
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سه شنبه 6 ارديبهشت 1390برچسب:, :: 18:43 ::  نويسنده : فردین

Motherboard

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In personal computers, a motherboard is the central printed circuit board (PCB) in many modern computers and holds many of the crucial components of the system, while providing connectors for other peripherals. The motherboard is sometimes alternatively known as the mainboard, system board, or, on Apple computers, the logic board.[1] It is also sometimes casually shortened to mobo.[2]

A motherboard for a desktop personal computer

Prior to the advent of the microprocessor, a computer was usually built in a card-cage case or mainframe with components connected by a backplane consisting of a set of slots themselves connected with wires; in very old designs the wires were discrete connections between card connector pins, but printed circuit boards soon became the standard practice. The Central Processing Unit, memory and peripherals were housed on individual printed circuit boards which plugged into the backplane.

During the late 1980s and 1990s, it became economical to move an increasing number of peripheral functions onto the motherboard (see below). In the late 1980s, motherboards began to include single ICs (called Super I/O chips) capable of supporting a set of low-speed peripherals: keyboard, mouse, floppy disk drive, serial ports, and parallel ports. As of the late 1990s, many personal computer motherboards supported a full range of audio, video, storage, and networking functions without the need for any expansion cards at all; higher-end systems for 3D gaming and computer graphics typically retained only the graphics card as a separate component.

The early pioneers of motherboard manufacturing were Micronics, Mylex, AMI, DTK, Hauppauge, Orchid Technology, Elitegroup, DFI, and a number of Taiwan-based manufacturers.

The most popular computers such as the Apple II and IBM PC had published schematic diagrams and other documentation which permitted rapid reverse-engineering and third-party replacement motherboards. Usually intended for building new computers compatible with the exemplars, many motherboards offered additional performance or other features and were used to upgrade the manufacturer's original equipment.

The term mainboard is applied to devices with a single board and no additional expansions or capability. In modern terms this would include embedded systems and controlling boards in televisions, washing machines, etc. A motherboard specifically refers to a printed circuit board with expansion capability.

[edit] Overview

A motherboard, like a backplane, provides the electrical connections by which the other components of the system communicate, but unlike a backplane, it also connects the central processing unit and hosts other subsystems and devices.

A typical desktop computer has its microprocessor, main memory, and other essential components connected to the motherboard. Other components such as external storage, controllers for video display and sound, and peripheral devices may be attached to the motherboard as plug-in cards or via cables, although in modern computers it is increasingly common to integrate some of these peripherals into the motherboard itself.

An important component of a motherboard is the microprocessor's supporting chipset, which provides the supporting interfaces between the CPU and the various buses and external components. This chipset determines, to an extent, the features and capabilities of the motherboard.

Modern motherboards include, at a minimum:

  • sockets (or slots) in which one or more microprocessors may be installed[3]
  • slots into which the system's main memory is to be installed (typically in the form of DIMM modules containing DRAM chips)
  • a chipset which forms an interface between the CPU's front-side bus, main memory, and peripheral buses
  • non-volatile memory chips (usually Flash ROM in modern motherboards) containing the system's firmware or BIOS
  • a clock generator which produces the system clock signal to synchronize the various components
  • slots for expansion cards (these interface to the system via the buses supported by the chipset)
  • power connectors, which receive electrical power from the computer power supply and distribute it to the CPU, chipset, main memory, and expansion cards.[4]
The Octek Jaguar V motherboard from 1993.[5] This board has 6 ISA slots but few onboard peripherals, as evidenced by the lack of external connectors.

Additionally, nearly all motherboards include logic and connectors to support commonly used input devices, such as PS/2 connectors for a mouse and keyboard. Early personal computers such as the Apple II or IBM PC included only this minimal peripheral support on the motherboard. Occasionally video interface hardware was also integrated into the motherboard; for example, on the Apple II and rarely on IBM-compatible computers such as the IBM PC Jr. Additional peripherals such as disk controllers and serial ports were provided as expansion cards.

Given the high thermal design power of high-speed computer CPUs and components, modern motherboards nearly always include heat sinks and mounting points for fans to dissipate excess heat.

[edit] CPU sockets

A CPU socket or slot is an electrical component that attaches to a printed circuit board (PCB) and is designed to house a CPU (also called a microprocessor). It is a special type of integrated circuit socket designed for very high pin counts. A CPU socket provides many functions, including a physical structure to support the CPU, support for a heat sink, facilitating replacement (as well as reducing cost), and most importantly, forming an electrical interface both with the CPU and the PCB. CPU sockets can most often be found in most desktop and server computers (laptops typically use surface mount CPUs), particularly those based on the Intel x86 architecture on the motherboard. A CPU socket type and motherboard chipset must support the CPU series and speed.

[edit] Integrated peripherals

Block diagram of a modern motherboard, which supports many on-board peripheral functions as well as several expansion slots.

With the steadily declining costs and size of integrated circuits, it is now possible to include support for many peripherals on the motherboard. By combining many functions on one PCB, the physical size and total cost of the system may be reduced; highly integrated motherboards are thus especially popular in small form factor and budget computers.

For example, the ECS RS485M-M,[6] a typical modern budget motherboard for computers based on AMD processors, has on-board support for a very large range of peripherals:

Expansion cards to support all of these functions would have cost hundreds of dollars even a decade ago; however, as of April 2007 such highly integrated motherboards are available for as little as $30 in the USA.

[edit] Peripheral card slots

A typical motherboard of 2009 will have a different number of connections depending on its standard.

A standard ATX motherboard will typically have one PCI-E 16x connection for a graphics card, two conventional PCI slots for various expansion cards, and one PCI-E 1x (which will eventually supersede PCI). A standard EATX motherboard will have one PCI-E 16x connection for a graphics card, and a varying number of PCI and PCI-E 1x slots. It can sometimes also have a PCI-E 4x slot. (This varies between brands and models.)

Some motherboards have two PCI-E 16x slots, to allow more than 2 monitors without special hardware, or use a special graphics technology called SLI (for Nvidia) and Crossfire (for ATI). These allow 2 graphics cards to be linked together, to allow better performance in intensive graphical computing tasks, such as gaming and video editing.

As of 2007, virtually all motherboards come with at least four USB ports on the rear, with at least 2 connections on the board internally for wiring additional front ports that may be built into the computer's case. Ethernet is also included. This is a standard networking cable for connecting the computer to a network or a modem. A sound chip is always included on the motherboard, to allow sound output without the need for any extra components. This allows computers to be far more multimedia-based than before. Some motherboards contain video outputs on the back panel for integrated graphics solutions (either embedded in the motherboard, or combined with the microprocessor, such as the Intel HD Graphics). A separate card may still be used.

[edit] Temperature and reliability

Motherboards are generally air cooled with heat sinks often mounted on larger chips, such as the Northbridge, in modern motherboards. If the motherboard is not cooled properly, it can cause the computer to crash. Passive cooling, or a single fan mounted on the power supply, was sufficient for many desktop computer CPUs until the late 1990s; since then, most have required CPU fans mounted on their heat sinks, due to rising clock speeds and power consumption. Most motherboards have connectors for additional case fans as well. Newer motherboards have integrated temperature sensors to detect motherboard and CPU temperatures, and controllable fan connectors which the BIOS or operating system can use to regulate fan speed. Some computers (which typically have high-performance microprocessors, large amounts of RAM, and high-performance video cards) use a water-cooling system instead of many fans.

Some small form factor computers and home theater PCs designed for quiet and energy-efficient operation boast fan-less designs. This typically requires the use of a low-power CPU, as well as careful layout of the motherboard and other components to allow for heat sink placement.

A 2003 study[7] found that some spurious computer crashes and general reliability issues, ranging from screen image distortions to I/O read/write errors, can be attributed not to software or peripheral hardware but to aging capacitors on PC motherboards. Ultimately this was shown to be the result of a faulty electrolyte formulation.[8]

For more information on premature capacitor failure on PC motherboards, see capacitor plague.

Motherboards use electrolytic capacitors to filter the DC power distributed around the board. These capacitors age at a temperature-dependent rate, as their water based electrolytes slowly evaporate. This can lead to loss of capacitance and subsequent motherboard malfunctions due to voltage instabilities. While most capacitors are rated for 2000 hours of operation at 105 °C,[9] their expected design life roughly doubles for every 10 °C below this. At 45 °C a lifetime of 15 years can be expected. This appears reasonable for a computer motherboard. However, many manufacturers have delivered substandard capacitors,[citation needed] which significantly reduce life expectancy. Inadequate case cooling and elevated temperatures easily exacerbate this problem. It is possible, but tedious and time-consuming, to find and replace failed capacitors on PC motherboards.

[edit] Form factor

microATX form factor motherboard

Motherboards are produced in a variety of sizes and shapes called computer form factor, some of which are specific to individual computer manufacturers. However, the motherboards used in IBM-compatible to fit various case sizes. As of 2007, most desktop computer motherboards use one of these[which?] standard form factors—even those found in Macintosh and Sun computers, which have not traditionally been built from commodity components. The current desktop PC form factor of choice is ATX. A case's motherboard and PSU form factor must all match, though some smaller form factor motherboards of the same family will fit larger cases. For example, an ATX case will usually accommodate a microATX motherboard.

Laptop computers generally use highly integrated, miniaturized and customized motherboards. This is one of the reasons that laptop computers are difficult to upgrade and expensive to repair. Often the failure of one laptop component requires the replacement of the entire motherboard, which is usually more expensive than a desktop motherboard due to the large number of integrated components.

[edit] Bootstrapping using the BIOS

Motherboards contain some non-volatile memory to initialize the system and load an operating system from some external peripheral device. Microcomputers such as the Apple II and IBM PC used ROM chips, mounted in sockets on the motherboard. At power-up, the central processor would load its program counter with the address of the boot ROM and start executing ROM instructions, displaying system information on the screen and running memory checks, which would in turn start loading memory from an external or peripheral device (disk drive). If none is available, then the computer can perform tasks from other memory stores or display an error message, depending on the model and design of the computer and version of the BIOS.

Most modern motherboard designs use a BIOS, stored in an EEPROM chip soldered or socketed to the motherboard, to bootstrap an operating system. When power is first applied to the motherboard, the BIOS firmware tests and configures memory, circuitry, and peripherals. This Power-On Self Test (POST) may include testing some of the following devices:

On recent motherboards, the BIOS may also patch the central processor microcode if the BIOS detects that the installed CPU is one in for which errata has been published. Many of the above devices can be stored with machine code instructions to load an operating system or program.

A motherboard of a Vaio E series laptop (right)

Contents

[hide]

[edit] History



یک شنبه 4 ارديبهشت 1390برچسب:, :: 17:50 ::  نويسنده : فردین

Grantee Perception Report Summary

 

June 15, 2010

In my annual letter last year, I announced that we were working with the Center for Effective Philanthropy (CEP) to survey all of our active grantees, in an effort to improve the quality of our external partnerships. Those partnerships are our lifeblood, and I said I was making it a priority for everybody at the foundation to listen more carefully to what our partners in the field have to tell us. I also promised to report back on what we found out—and on how we are responding to the feedback. That is why I am writing this letter.

I appreciate our grantee partners’ willingness to be part of this process. The GPR has taught us a great deal, and it is already helping us improve the way we work.

Before I get into the details of what we learned and how we’re responding, I want to explain a little more about the Grantee Perception Report (GPR).It’s a comprehensive survey of grantees that covers a range of issues, and because so many organizations use the GPR—it has been commissioned by nearly 200 philanthropic funders—it allows us to be benchmarked against other funders in the field.

The CEP surveyed 1,544 of our grantees, all our active grantees between June 1, 2008 and May 31, 2009. 1,020 responded, and the 66 percent response rate is typical of this survey.

Now, on to the results.

First, compared to other funders in the CEP’s comparative database, the foundation received strong ratings for our work in grantees’ fields. In particular, they said we have a positive impact on knowledge, policy, and practice in our strategy areas.

But we received lower than typical ratings on many other aspects of the grantee experience.

Many of our grantee partners said we are not clear about our goals and strategies, and they think we don’t understand their goals and strategies.

They are confused by our decision-making and grantmaking processes.

Because of staff turnovers, many of our grantee partners have had to manage multiple Program Officer transitions during the course of their grant, which creates more work.

Finally, they say we are inconsistent in our communications, and often unresponsive.

We take this feedback very seriously, because we understand that some of these barriers are preventing our partners and us from having our maximum impact.

The GPR results were the focus of many management team meetings at the beginning of the year. In the spring, we built on those high-level meetings with a foundation-wide dialogue, which helped our staff understand the results and collectively analyze what they mean to us.

Through this process, we have developed a long-term vision of success and a series of action steps to get there. We don’t see this process as a popularity contest. Even in the most productive partnerships, there is bound to be some tension. But we are absolutely committed to building relationships that will help us do our best work.

I have set a simple three year goal for us. By 2013, the foundation and our grantee partners will have stronger partnerships characterized by three things:

  • First, we will understand each others’ roles, goals, and strategies
  • Second, we will have open, two-way communication
  • Third, they will have a clear understanding of our decision-making and grantmaking processes

 

To reach these goals, we identified five short–term action steps to improve our grantee partnerships immediately. Specifically, our commitments to our grantee partners in the short-term are:

  1. To better explain how our proposal and approval process works
  2. To clearly communicate the point of contact for grants
  3. To orient all new grantees, set expectations, and answer their questions and hear their concerns at the outset.
  4. To provide timely and substantive responses to all the progress reports they submit
  5. To open up new channels of communication, including more frequent check-in calls with program managers and conference calls that give all our grantee partners the chance to ask questions of our executives.

We are also now working on a long-term action plan to address more systemic issues that affect our relationships with our grantees. We are committed to building strong partnerships, and we realize that doing so may require fundamental changes in the way we work.

With that in mind, I am also committed to commissioning another GPR in 2013 to check on our progress toward our goals.

 fardin salim pour azar

CEO



یک شنبه 4 ارديبهشت 1390برچسب:, :: 17:37 ::  نويسنده : فردین

2011 Annual Letter from Bill Gates: The Giving Pledge

Warren Buffett is a remarkable friend and mentor to both Melinda and me, and we have learned so much from spending time with him and working with him on foundation projects. A few years ago Warren suggested that he, Melinda, and I should get together with some of the most generous givers in the country and see what we could learn from them. We started out by having dinners where everyone talked about why they give, what they are passionate about, and what they wish they could do better. The dinners evolved into discussions of the challenges of giving effectively. It became clear that there was a lot of collective knowledge and that we could inspire each other and in some cases work together. There was a strong sense we should broaden the discussion to a larger group including people who were earlier in their giving career.

This led to the idea of the Giving Pledge. It is simply a commitment to give the majority of your wealth away during your lifetime or through your will. We hope that over the long term it will encourage people to start earlier, collaborate more, and make their giving even more impactful.

We are excited that 58 people have already joined the Giving Pledge. You can see the letters describing their thinking about giving at www.givingpledge.org. The United States is the most generous country in the world. More than 15 percent of the large estates go to charity. That is significant, but there is room for that to increase. Warren has said, “We want the general level of giving to step up. We want the Pledge to help society become even more generous. We hope the norm will change towards even greater and smarter philanthropy.”

Although this effort is focused on those people in the United States with the greatest wealth, we are encouraged by and support similar efforts that focus on other groups. For example, some of the top business people in China and India asked if we would meet with them to stimulate discussion about giving in their country. Warren and I had the meeting in China in November and we were very happy with how many people came and how the conversation turned out. All three of us will be attending a similar meeting in India in the first half of the year.

Clockwise, from top left: Geetanjali in her bakery with her son and daughter (New Delhi, 2010). Woman carries maize to market (Kunsu, Ghana, 2010). Kamla Devi at her roadside flower shop (New Delhi, 2010). Child receives oral polio vaccine (Kano, Nigeria, 2010). Students learn about biotech in Dr. Kinchington’s 10th grade class at the Science and Technology Academy (Pittsburgh, Pennsylvania, 2010).


یک شنبه 4 ارديبهشت 1390برچسب:, :: 17:37 ::  نويسنده : فردین

2011 Annual Letter from Bill Gates:
Continuing the Conversation

 
Last year I launched www.gatesnotes.com and started a Twitter feed (@BillGates) to share my thoughts on the work we’re doing and what I’m learning from leaders and innovators. One great benefit of these tools is that they allow me to hear back from people. Over the next year I’ll be trying some new ways of adding interactivity to the site so I can get even more feedback.

Melinda is also very interested in spurring a broader conversation about the issues she’s focused on at the foundation. Last year she started posting regularly to the foundation’s blog. She also hosted a terrific TEDx event (www.tedxchange.org/pastevents) in New York that brought together interesting speakers on global health and development. Next year, building on her relationship with TED, she’ll be hosting a series of “TEDxChange” events in communities around the world—in places like Kenya and India. The goal of these TEDxChange events is to give people a chance to hear about health and development from people who live in the places where the work is happening.

Despite government budget difficulties and the complexity of solving the key problems the foundation’s work addresses, Melinda and I remain optimistic. We meet so many remarkable leaders whose work is making the world a better place.

My father, our co-chair, set the foundation’s direction from the start and he always helps us keep in mind what is important. Jeff Raikes, our CEO, continues to add great people and improve the way we do our work. Not everyone can go to the field, or even donate. But every one of us can be an advocate for people whose voices are often not heard. I encourage everyone to get involved in working for solutions to the challenges those people face. It will draw you in for life.

fardin salim pour azar

Co-chair, Bill & Melinda Gates Foundation
January 2011



یک شنبه 4 ارديبهشت 1390برچسب:, :: 17:35 ::  نويسنده : فردین

2011 Annual Letter from Bill Gates:
Excellence in Teaching

In the United States, the foundation’s biggest investments are in education. Only a third of students are graduating from high school prepared to succeed at college-level work, and even fewer are going on to get a degree that will help them compete for a good job. No one should feel comfortable with those results.

Davis Guggenheim's amazing and popular movie Waiting for “Superman” made a powerful argument against the status quo. It showed a broad audience that schools with the right approach can succeed, even with inner city students that typical schools do not educate well. As more people understand the gap between what is possible and what is actually happening in most schools, I believe the momentum for reform will grow.

Since 1980 U.S. government spending per K-12 student increased by 73 percent, which is 20 percent faster than the rest of the economy. Over that time our achievement levels were basically flat, while other countries caught up. A recent analysis by the Programme for International Student Assessment (PISA) showed the United States is about average (compared to 35 developed countries) in science and reading and below average in math. Many Americans have a hard time believing this data, since we are so used to being the global leader in educational achievement and since we spend a lot more money on education than many other countries.

PISA measured educational achievement in the Shanghai area of China, and even allowing for the fact that Shanghai is one of the most advanced parts of China, the scores relative to the United States and other countries were quite stunning. China did better in math, science, and reading than any of the 65 countries it was compared to, and it achieved these results with an average class size of more than 35 students. One of the impressive things about the Chinese system is how teachers are measured according to their ability. There are four levels of proficiency in the Chinese system, and to move up a level, teachers have to demonstrate their excellence in front of a panel of reviewers.

According to the PISA analysis (available at www.pisa.oecd.org), two key things differentiate the U.S. education system from most other countries’ systems. The first is that non-U.S. students are in school for more hours, and the second is that U.S. school systems do very little to measure, invest in, and reward teacher excellence.

Most people who become teachers do so because they’re passionate about kids. It’s astonishing what great teachers can do for their students. But the remarkable thing about great teachers today is that in most cases nobody taught them how to be great. They figured it out on their own. That’s why our foundation is investing to help devise measurement and support systems to help good teachers become great teachers.

Geoffrey Canada talks with students at Harlem Children’s Zone, in a scene from Waiting for “Superman” (New York City, 2009). © Paramount Pictures/Participant Media

Our project to learn what the best teachers do—and how to share this information with other teachers—is making significant progress. With the help of local union affiliates, we have learned a lot already. We’re learning that listening to students can be an important element in the feedback system. In classes where students agree that “Our class stays busy and doesn't waste time” or that “In this class, we learn a lot almost every day,” there tend to be bigger achievement gains.

Another great tool is taking a video showing both the teacher and the students and asking evaluators to provide feedback. Melinda and I spent several days visiting schools in Tennessee this fall and sat with teachers who were watching videos of themselves teaching. We heard from a number of them how they had already improved by seeing when students were losing interest and analyzing the reasons.

Ultimately, the goal is to gather high-quality feedback from multiple sources—test scores, student surveys, videos, principals, and fellow teachers—so that teachers know how to improve. I think it is clear that a system can be designed that teachers agree is fair, has modest overhead, and rewards the teachers who are doing the most for their students.

State budgets, the biggest part of K-12 funding, will be challenged in the years ahead because of the economic downturn, the liabilities from early retirement and pension commitments, and increasing medical costs. I recently gave a speech to the chief state school officers (http://www.gatesfoundation.org/ccsso) about how they might need to find money to reward excellent teaching by shifting some away from things like payment for seniority or advanced degrees that do not correlate with improved teaching.

I am very enthusiastic about the potential of innovation to help solve many of the problems with our education system. Melinda and I were impressed when we visited the Tennessee Technology Center in Nashville, an institution that provides young adults with technical training and certificates. It gets significantly better results than its peer institutions—graduating 71 percent of its students—because it focuses on teaching job skills that are in high demand and is oriented around meeting the needs of students who are juggling school with work and family. Sometimes something as simple as rethinking the times when classes are scheduled makes a huge difference for students.

The foundation is funding the development of online tools to help both K-12 and college students learn. Pioneers like Sal Khan are already showing how effective online tools can be. His website www.khanacademy.org continues to grow its library of 2,000 short instructional videos on topics from basic arithmetic to complicated subjects like biology and physics. The videos are a tremendous resource for students of any age.

Sal’s vision for how technology can improve learning is broader than just videos. With support from the foundation, he’s been able to expand his site to include online exercises that diagnose weak spots, pointing you to additional material to fill the gaps in your knowledge. Also, Khan Academy is creating on online “dashboard” to help teachers use the site as part of their curriculum. The dashboard tells the teacher how each student is doing, pinpoints where they’re having trouble, and suggests explanations and exercises to help.

Although it is clear that online learning works for strongly motivated students, we need to learn how to blend classroom learning and online learning, particularly for younger and less-prepared students. As these projects develop and we start to answer many of these questions, I believe technology will let us dramatically improve education despite the budget constraints.



یک شنبه 4 ارديبهشت 1390برچسب:, :: 15:41 ::  نويسنده : فردین

2011 Annual Letter from Bill Gates:
Agriculture’s Great Promise

Outside of health the area where we invest the most to help poor people is agriculture. There is so much potential in agricultural development because most poor people in the world feed their families and earn their income from farming. When farmers increase their productivity, nutrition is improved and hunger and poverty are reduced. In countries like Rwanda, Ethiopia, and Tanzania, investments in seeds, training, access to markets, and innovative agricultural policy are making a real difference. Ghana made agriculture a priority and cut hunger by 75 percent between 1990 and 2004. The increase in food production has led to economic development in other areas.

But the growth in other countries has been slower. These are complex issues, and it’s going to take strong leadership to make sure farmers have the opportunity to seize their potential. Kofi Annan, who chairs the Alliance for a Green Revolution in Africa, is leading the way by helping to drive a new agriculture agenda for the continent.

One program I’m especially enthusiastic about is a partnership launched in 2008 with the World Food Programme (WFP), the world’s largest humanitarian agency for fighting hunger. What I like about it is that it takes a new approach to something the world has been doing for a long time, food aid.

In the past most small farmers were not able to sell their produce to WFP to be used as food aid. They had trouble meeting WFP’s complicated requirements and delivering food in bulk quantities that met WFP’s quality standards. Our partnership works with farmers and others to resolve these issues, making it possible for them to sell to lots of additional buyers including WFP. When the West African country of Niger experienced a famine last summer, WFP bought 1,000 metric tons of rice from a farmers’ organization in Mali. When small farmers in Mali are earning extra income by feeding hungry families in Niger, it’s a clear win-win.

The near-term rise in food prices and the long-term increased demand for food will create opportunities for small farmers even in the poorest countries. In fact, increasing production in Africa will be critical for the world to have enough food. It’s encouraging that foreign aid for agriculture has now increased from its historic low of just $2.8 billion in 2003 to $5.9 billion in 2009, and it’s critical that nations don’t cut back again.

One of the most important new developments came in April when I joined the finance ministers of the United States, Spain, Canada, and South Korea to launch the Global Agriculture and Food Security Program with initial commitments of nearly $1 billion over three years. This program provides support to developing countries with strong domestic agricultural development plans that they are already investing in themselves but cannot fully fund. It has generated amazing demand, demonstrating how committed poor nations are to their own agricultural development.

Farmer prepares dried maize (corn) for sale (Monopo, Mozambique, 2010). Farmer separates maize from stalks (Malawi, 2010). © Charlie Barnwell, World Food Programme


یک شنبه 4 ارديبهشت 1390برچسب:, :: 15:38 ::  نويسنده : فردین

2011 Annual Letter from Bill Gates:
Saving the Youngest Children

Of the 8.1 million deaths per year of children under the age of 5, over 40 percent happen in the first 28 days of life, or the neonatal period. The good news is that we are headed in the right direction. In 1995 there were an estimated 5.6 million neonatal deaths. The most recent estimates show the number down to around 3.6 million.

Unlike the deaths that take place after a child is 28 days old, almost all of which can be prevented by inventing and delivering vaccines, reducing these early deaths requires a range of approaches. Some require new tools such as an ointment for the baby’s skin that prevents infection and an antibiotic solution for cleaning the cut umbilical cord. However, many of the key interventions involve social and behavioral change. You can have a huge impact (on both newborn and maternal health) by increasing the number of births done by a skilled provider in a clinic. It’s also important to teach mothers to wash their hands before handling a baby, to have frequent skin-to-skin contact with their babies, and to breastfeed exclusively for the baby’s first six months. (Mother’s milk contains not only key nutrition but also antibodies that block infection until the baby’s immune system is ready to operate on its own.) Where all of these elements come together, neonatal deaths can be reduced by 50 percent or more, so it’s critical that we learn more about how to teach and motivate mothers effectively, especially at a large scale.

Melinda has been a strong leader on maternal and child health issues. She gave an especially powerful speech last year to the Women Deliver conference (http://www.gatesfoundation.org/womendeliver). The plight of mothers and their babies is something she feels deeply, and it’s something we talk about a lot.

When she came home from a trip to Malawi she shared the experience of seeing two babies in a hospital in the town of Lilongwe, lying side-by-side in the same incubator. They were born within hours of each other. Each had suffered the same condition–they were unable to breathe at birth. Sadly, it was clear that only one would survive. That baby’s mother had made it to the donor-funded hospital in time for her delivery and was able to get the care she needed. Her baby was immediately resuscitated, which saved his life. The other was not so fortunate. He was born on the way to the clinic, on the side of road, and was not resuscitated soon enough. I wish everyone had a chance to experience what Melinda did, so they could see how things are improving but also understand the urgent need to do more.

Shanti Devi holds her newborn daughter (Koelikhera Village, India, 2004). Melinda observes newborn babies at Bwaila Hospital (Lilongwe, Malawi, 2010).


یک شنبه 4 ارديبهشت 1390برچسب:, :: 15:37 ::  نويسنده : فردین

2011 Annual Letter from Bill Gates: Miracle of Vaccines

In the same way that during my Microsoft career I talked about the magic of software, I now spend my time talking about the magic of vaccines. Vaccines have taken us to the threshold of eradicating polio. They are the most effective and cost-effective health tool ever invented. I like to say vaccines are a miracle. Just a few doses of vaccine can protect a child from debilitating and deadly diseases for a lifetime. And most vaccines are extremely inexpensive. For example, the polio vaccine costs 13 cents a dose.

This year 1.4 million children will die from diseases for which there are already vaccines—diseases like measles, pneumonia, and tetanus. Those lives can be saved if we can reduce the costs of vaccines and raise enough money to buy and distribute them. If we simply scale up existing vaccines in the five countries with the highest number of child deaths, we could save 3 million lives (and more than $2.9 billion in treatment costs alone) over the next decade. In addition, researchers are inventing new vaccines for malaria, AIDS, and tuberculosis, and these would save millions more lives. But generous aid is required to realize the true lifesaving potential of vaccines. The most direct way of saying this is that every $2,000 cut in the most effective aid spending causes a child to die.

A few years ago I was looking into the history of vaccination coverage. In 1980 less than 20 percent of children worldwide received the vaccinations for diseases including measles, diphtheria, tetanus, and whooping cough (pertussis) that children in rich countries were receiving. Less than 15 years later, in 1995, vaccination rates had been raised to over 70 percent. Just this year I finally got around to learning why there was such a huge increase. The head of UNICEF at the time, Jim Grant, led the way. The book Jim Grant–UNICEF Visionary tells his amazing story. Since there are only a few used copies of this in circulation UNICEF recently made a free version available at http://www.unicef.org/publications/index_4402.html.

I’m surprised by how little attention his story gets and how long it took me to find out about it. I was inspired by reading how he drove global progress even during the tough economic decade of the 1980s. We can draw lessons from his leadership now, in our own tough economic times.

As is often the case with courageous efforts, many people resisted Jim Grant’s push, viewing it as too top-down. However, he managed to enlist a number of countries to lead the way, and as the number of deaths in those countries dropped dramatically he was able to persuade almost every country to run strong vaccination campaigns. It is especially amazing that he did this in an age when there was no Internet and no email. Jim Grant’s achievement is the greatest miracle of saving children’s lives ever.



The benefits of widespread vaccination are mostly explained in terms of the lives vaccines save, and based on that measure alone, vaccines are the best investment to improve the human condition. However, there are two other equally important benefits that are not as widely known partly because they are harder to quantify.

The first is the reduction in sickness. I don’t mean just the acute sickness where a child is clearly suffering from the disease, but also the permanent disabilities caused by the disease. This is most noticeable when the disability presents with a clear symptom such as being paralyzed by polio or going deaf because of a pneumococcal infection. However, the largest disability is the effect on mental development. For example, severe cerebral malaria damages your brain even if you survive. When children have lots of diarrheal episodes or parasites in their intestines, they don’t get enough nutrition for their brains to develop fully.

The huge infectious disease burden in poor countries means that a substantial part of their human potential is lost by the time children are 5 years old. A group of researchers at the University of New Mexico conducted a study, covered in The Economist, showing the correlation between lower IQ and a high level of disease in a country. Although an IQ test is not a perfect measure, the dramatic effect you see is a huge injustice. It helps explain why countries with high disease burdens have a hard time developing their economies as easily as countries with less disease.

The second great benefit of vaccination is that as the childhood death rate is reduced, within 10 to 20 years this reduction is strongly associated with families choosing to have fewer children. While it might seem logical that saving children’s lives will cause overpopulation, the opposite is true.

I mention this amazing connection often, since I remember how I had to hear it multiple times before the full implications of it became clear. It is the reason why childhood health issues are key to so many other issues, including having resources for education, providing enough jobs, and not destroying the environment. Only when Melinda and I understood this connection did we make the full commitment to health issues, especially vaccination.

The connection of health to education, jobs, and the environment points back to the tremendous value of high-quality international aid—and why it’s essential that donor nations not cut their spending on it. Melinda and I have committed $10 billion from the foundation over the next 10 years to help make this the Decade of Vaccines. However, this will fall well short of what is needed.

The group which helps poor countries purchase vaccines and increase vaccine coverage is the GAVI Alliance and like the polio campaign its success will depend on donor generosity.



The foundation’s website does a great job of outlining all of our strategies, but in the remainder of my letter I want to highlight a few specific areas. The world has made some crucial breakthroughs, and with bold leadership I think we can do even more.



یک شنبه 4 ارديبهشت 1390برچسب:, :: 15:37 ::  نويسنده : فردین

2011 Annual Letter from Bill Gates: Miracle of Vaccines

In the same way that during my Microsoft career I talked about the magic of software, I now spend my time talking about the magic of vaccines. Vaccines have taken us to the threshold of eradicating polio. They are the most effective and cost-effective health tool ever invented. I like to say vaccines are a miracle. Just a few doses of vaccine can protect a child from debilitating and deadly diseases for a lifetime. And most vaccines are extremely inexpensive. For example, the polio vaccine costs 13 cents a dose.

This year 1.4 million children will die from diseases for which there are already vaccines—diseases like measles, pneumonia, and tetanus. Those lives can be saved if we can reduce the costs of vaccines and raise enough money to buy and distribute them. If we simply scale up existing vaccines in the five countries with the highest number of child deaths, we could save 3 million lives (and more than $2.9 billion in treatment costs alone) over the next decade. In addition, researchers are inventing new vaccines for malaria, AIDS, and tuberculosis, and these would save millions more lives. But generous aid is required to realize the true lifesaving potential of vaccines. The most direct way of saying this is that every $2,000 cut in the most effective aid spending causes a child to die.

A few years ago I was looking into the history of vaccination coverage. In 1980 less than 20 percent of children worldwide received the vaccinations for diseases including measles, diphtheria, tetanus, and whooping cough (pertussis) that children in rich countries were receiving. Less than 15 years later, in 1995, vaccination rates had been raised to over 70 percent. Just this year I finally got around to learning why there was such a huge increase. The head of UNICEF at the time, Jim Grant, led the way. The book Jim Grant–UNICEF Visionary tells his amazing story. Since there are only a few used copies of this in circulation UNICEF recently made a free version available at http://www.unicef.org/publications/index_4402.html.

I’m surprised by how little attention his story gets and how long it took me to find out about it. I was inspired by reading how he drove global progress even during the tough economic decade of the 1980s. We can draw lessons from his leadership now, in our own tough economic times.

As is often the case with courageous efforts, many people resisted Jim Grant’s push, viewing it as too top-down. However, he managed to enlist a number of countries to lead the way, and as the number of deaths in those countries dropped dramatically he was able to persuade almost every country to run strong vaccination campaigns. It is especially amazing that he did this in an age when there was no Internet and no email. Jim Grant’s achievement is the greatest miracle of saving children’s lives ever.



The benefits of widespread vaccination are mostly explained in terms of the lives vaccines save, and based on that measure alone, vaccines are the best investment to improve the human condition. However, there are two other equally important benefits that are not as widely known partly because they are harder to quantify.

The first is the reduction in sickness. I don’t mean just the acute sickness where a child is clearly suffering from the disease, but also the permanent disabilities caused by the disease. This is most noticeable when the disability presents with a clear symptom such as being paralyzed by polio or going deaf because of a pneumococcal infection. However, the largest disability is the effect on mental development. For example, severe cerebral malaria damages your brain even if you survive. When children have lots of diarrheal episodes or parasites in their intestines, they don’t get enough nutrition for their brains to develop fully.

The huge infectious disease burden in poor countries means that a substantial part of their human potential is lost by the time children are 5 years old. A group of researchers at the University of New Mexico conducted a study, covered in The Economist, showing the correlation between lower IQ and a high level of disease in a country. Although an IQ test is not a perfect measure, the dramatic effect you see is a huge injustice. It helps explain why countries with high disease burdens have a hard time developing their economies as easily as countries with less disease.

The second great benefit of vaccination is that as the childhood death rate is reduced, within 10 to 20 years this reduction is strongly associated with families choosing to have fewer children. While it might seem logical that saving children’s lives will cause overpopulation, the opposite is true.

I mention this amazing connection often, since I remember how I had to hear it multiple times before the full implications of it became clear. It is the reason why childhood health issues are key to so many other issues, including having resources for education, providing enough jobs, and not destroying the environment. Only when Melinda and I understood this connection did we make the full commitment to health issues, especially vaccination.

The connection of health to education, jobs, and the environment points back to the tremendous value of high-quality international aid—and why it’s essential that donor nations not cut their spending on it. Melinda and I have committed $10 billion from the foundation over the next 10 years to help make this the Decade of Vaccines. However, this will fall well short of what is needed.

The group which helps poor countries purchase vaccines and increase vaccine coverage is the GAVI Alliance and like the polio campaign its success will depend on donor generosity.



The foundation’s website does a great job of outlining all of our strategies, but in the remainder of my letter I want to highlight a few specific areas. The world has made some crucial breakthroughs, and with bold leadership I think we can do even more.



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