Monday, 22 December 2014
People are living much longer worldwide than they were two decades ago, as death rates from infectious diseases and cardiovascular disease have fallen, according to a new, first-ever journal publication of country-specific cause-of-death data for 188 countries.
Causes of death vary widely by country, but, at the global level, drug use disorders and chronic kidney disease account for some of the largest percent increases in premature deaths since 1990. Death rates from some cancers, including pancreatic cancer and kidney cancer, also increased. At the same time, countries have made great strides in reducing mortality from diseases such as measles and diarrhea, with 83% and 51% reductions, respectively, from 1990 to 2013.
Globally, three conditions – ischemic heart disease, stroke, and chronic obstructive pulmonary disease (COPD) – claimed the most lives in 2013, accounting for nearly 32% of all deaths.
Published in The Lancet on December 18, the study, “Global, regional, and national age-sex-specific all-cause and cause-specific mortality for 240 causes of death, 1990-2013: a systematic analysis for the Global Burden of Disease Study 2013,” was conducted by an international consortium of more than 700 researchers led by the Institute for Health Metrics and Evaluation (IHME) at the University of Washington.
Compared to previous Global Burden of Disease (GBD) studies, researchers from more than 100 nations incorporated more country-level data as well as additional data on specific conditions. They also examined whether leading causes of death in lower-income countries are beginning to mirror those in higher-income countries. What they found is that even with big improvements in longevity in low-income countries, the types of health challenges faced by countries such as Bolivia, Nepal, and Niger are far different from those faced by countries such as Japan, Spain, and the United States. The health challenges of many middle-income countries such as China or Brazil are also closer to those in the US.
The average age of death increased from 46.7 in 1990 to 59.3 in 2013, as a result of declining fertility and a demographic shift in the world’s population to older ages. Partly because of global population growth, the number of deaths in both sexes for all ages combined increased from 47.5 million to 54.9 million.
The number of people dying from certain conditions, such as heart disease, has increased as population has increased, but decreases in age-specific mortality rates for these conditions is a sign of progress. Death rates from most cancers, including breast cancer, cervical cancer, and colon cancer, have decreased, but the reverse is true for pancreatic cancer, kidney cancer, and non-Hodgkin lymphoma.
“People today are less likely than their parents to die from certain conditions, but there are more people of older ages throughout the world,” said IHME Director Dr. Christopher Murray. “This is an encouraging trend as people are living longer. We just need to make sure we are making the right health policy decisions today to prepare for the health challenges and associated costs that are coming.”
Global life expectancy for both sexes increased from 65.3 years in 1990 to 71.5 years in 2013, and women made slightly greater gains than men. Female life expectancy at birth increased by 6.6 years and male life expectancy by 5.8 years. If trends seen over the past 23 years hold, by 2030 global female life expectancy will be 85.3 years and male life expectancy will be 78.1 years.
Disparities remain across age groups and countries. In all age groups except 80 and older, mortality has decreased more for women than men. Men aged 30-39 and over 80 showed some of the smallest declines in mortality. The gender gap in death rates for adults between the ages of 20 and 44 is widening, and HIV/AIDS, interpersonal violence, road injury, and maternal mortality are some of the key conditions responsible. For children under 5, diarrheal diseases, lower respiratory tract infections, neonatal disorders, and malaria are still among the leading causes of death.
Given the size of India’s population in particular, and projections that it may soon become the world’s most populous country, mortality trends there have global implications. In 2013, India accounted for 19%, or 10.2 million, of the world’s deaths. The country has made great strides in reducing both child and adult mortality since 1990. The average yearly rates of decline in mortality have been 3.7% per year for children and 1.3% per year for adults. Between 1990 and 2013, life expectancy at birth increased from 57.3 years to 64.2 years for males and from 58.2 years to 68.5 years for females.
“It’s very encouraging that adults and children in India are living longer and healthier lives,” said Dr. Jeemon Panniyammakal of the Public Health Foundation of India and a co-author of the study. “But India’s growing influence on global health means we must do more to address the diseases that kill people prematurely.”
In other parts of the world, life expectancy gains in sub-Saharan Africa were mainly driven by reductions in deaths from diarrhea, lower respiratory tract infections, and neonatal disorders. Reductions in cardiovascular disease, some cancers, transport injuries, and chronic respiratory conditions have led to the longevity gains in high-income regions.
A variety of causes contributed to life expectancy declines globally. Diabetes, other endocrine disorders, and chronic kidney disease decreased life expectancy across many regions, including central Latin America; mental disorders had a negative impact in multiple regions, especially North America; intentional injuries reduced life expectancy in South Asia, the high-income countries of the Asia Pacific region, and southern sub-Saharan Africa. In Eastern Europe and Central Asia, cirrhosis took a toll on life expectancy. HIV/AIDS was a major cause of death in Southern sub-Saharan Africa and to a smaller extent in Western and Eastern sub-Saharan Africa.
“Almost a decade after HIV/AIDS peaked globally, this remains the leading cause of premature death in more than a dozen countries in sub-Saharan Africa,” said Dr. Andre Kengne, of the South African Medical Research Council, and a co-author of the study. “As fewer young people die from childhood diseases we must do more to ensure that HIV/AIDS does not become a threat for people of all ages.”
When looking at other causes of death, progress is seen in lower death rates despite increasing numbers of deaths. Some of the biggest increases in premature mortality since 1990 were seen for diabetes, HIV/AIDS, hypertensive heart disease, chronic kidney disease, and Alzheimer’s disease. But for many disorders, including stomach cancer, Hodgkin’s lymphoma, rheumatic heart disease, peptic ulcer disease, appendicitis, and schizophrenia, death rates have fallen by more than one-third since 1990.
Death rates for some cancers have fallen (lung by 9%, breast by 18%, and leukemia by 20%). Global age-standardized death rates also have fallen by more than one-fifth for ischemic heart disease and stroke.
Overall, global mortality rates increased significantly for very few diseases between 1990 and 2013.
Leading causes of death globally, with the number of deaths
- Ischemic heart disease (8,139,900)
- Stroke (6,446,900)
- Chronic obstructive pulmonary disease (2,931,200)
- Pneumonia (2,652,600)
- Alzheimer’s disease (1,655,100)
- Lung cancer (1,639,600)
- Road injuries (1,395,800)
- HIV/AIDS (1,341,000)
- Diabetes (1,299,400)
- Tuberculosis (1,290,300)
- Ischemic heart disease (5,737,500)
- Stroke (4,584,800)
- Pneumonia (3,420,700)
- Diarrheal diseases (2,578,700)
- Chronic obstructive pulmonary disease (2,421,300)
- Tuberculosis (1,786,100)
- Neonatal preterm birth complications (1,570,500)
- Road injuries (1,058,400)
- Lung cancer (1,050,000)
- Malaria (888,100)
Download the study at: http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(14)61682-2/abstract
The Institute for Health Metrics and Evaluation (IHME) is an independent global health research organization at the University of Washington that provides rigorous and comparable measurement of the world’s most important health problems and evaluates the strategies used to address them. IHME makes this information widely available so that policymakers have the evidence they need to make informed decisions about how to allocate resources to best improve population health.
Thursday, 13 November 2014
TOUCHDOWN! ROSETTA’S PHILAE PROBE LANDS ON COMET
As of 12 November 2014:
ESA’s Rosetta mission has soft-landed its Philae probe on a comet, the first time in history that such an extraordinary feat has been achieved.
As reported by ESA, after a tense wait during the seven-hour descent to the surface of Comet 67P/Churyumov–Gerasimenko, the signal confirming the successful touchdown arrived on Earth at 16:03 GMT (17:03 CET).
The confirmation was relayed via the Rosetta orbiter to Earth and picked up simultaneously by ESA’s ground station in Malargüe, Argentina and NASA’s station in Madrid, Spain. The signal was immediately confirmed at ESA’s Space Operations Centre, ESOC, in Darmstadt, and DLR’s Lander Control Centre in Cologne, both in Germany.
The first data from the lander’s instruments were transmitted to the Philae Science, Operations and Navigation Centre at France’s CNES space agency in Toulouse.
“Our ambitious Rosetta mission has secured a place in the history books: not only is it the first to rendezvous with and orbit a comet, but it is now also the first to deliver a lander to a comet’s surface,” noted Jean-Jacques Dordain, ESA’s Director General.
“With Rosetta we are opening a door to the origin of planet Earth and fostering a better understanding of our future. ESA and its Rosetta mission partners have achieved something extraordinary today.”
“After more than 10 years travelling through space, we’re now making the best ever scientific analysis of one of the oldest remnants of our Solar System,” said Alvaro Giménez, ESA’s Director of Science and Robotic Exploration.
“Decades of preparation have paved the way for today’s success, ensuring that Rosetta continues to be a game-changer in cometary science and space exploration.”
“We are extremely relieved to be safely on the surface of the comet, especially given the extra challenges that we faced with the health of the lander,” said Stephan Ulamec, Philae Lander Manager at the DLR German Aerospace Center.
“In the next hours we’ll learn exactly where and how we’ve landed, and we’ll start getting as much science as we can from the surface of this fascinating world.”
Rosetta was launched on 2 March 2004 and travelled 6.4 billion kilometres through the Solar System before arriving at the comet on 6 August 2014.
“Rosetta’s journey has been a continuous operational challenge, requiring an innovative approach, precision and long experience,” said Thomas Reiter, ESA Director of Human Spaceflight and Operations.
“This success is testimony to the outstanding teamwork and the unique knowhow in operating spacecraft acquired at the European Space Agency over the decades.”
The landing site, named Agilkia and located on the head of the bizarre double-lobed object, was chosen just six weeks after arrival based on images and data collected at distances of 30–100 km from the comet. Those first images soon revealed the comet as a world littered with boulders, towering cliffs and daunting precipices and pits, with jets of gas and dust streaming from the surface.
Following a period spent at 10 km to allow further close-up study of the chosen landing site, Rosetta moved onto a more distant trajectory to prepare for Philae’s deployment.
Five critical go/no-go decisions were made last night and early this morning, confirming different stages of readiness ahead of separation, along with a final preseparation manoeuvre by the orbiter.
Deployment was confirmed at 09:03 GMT (10:03 CET) at a distance of 22.5km from the centre of the comet. During the seven-hour descent, which was made without propulsion or guidance, Philae took images and recorded information about the comet’s environment.
“One of the greatest uncertainties associated with the delivery of the lander was the position of Rosetta at the time of deployment, which was influenced by the activity of the comet at that specific moment, and which in turn could also have affected the lander’s descent trajectory,” said Sylvain Lodiot, ESA Rosetta Spacecraft Operations Manager.
“Furthermore, we’re performing these operations in an environment that we’ve only just started learning about, 510 million kilometres from Earth.”
Touchdown was planned to take place at a speed of around 1 m/s, with the three-legged landing gear absorbing the impact to prevent rebound, and an ice screw in each foot driving into the surface.
But during the final health checks of the lander before separation, a problem was detected with the small thruster on top that was designed to counteract the recoil of the harpoons to push the lander down onto the surface. The conditions of landing – including whether or not the thruster performed – along with the exact location of Philae on the comet are being analysed.
The first images from the surface are being downlinked to Earth and should be available within a few hours of touchdown.
Science highlights from the primary phase will include a full panoramic view of the landing site, including a section in 3D, high-resolution images of the surface immediately underneath the lander, on-the-spot analysis of the composition of the comet’s surface materials, and a drill that will take samples from a depth of 23 cm and feed them to an onboard laboratory for analysis.
The lander will also measure the electrical and mechanical characteristics of the surface. In addition, low-frequency radio signals will be beamed between Philae and the orbiter through the nucleus to probe the internal structure.
The detailed surface measurements that Philae makes at its landing site will complement and calibrate the extensive remote observations made by the orbiter covering the whole comet.
“Rosetta is trying to answer the very big questions about the history of our Solar System. What were the conditions like at its infancy and how did it evolve? What role did comets play in this evolution? How do comets work?” said Matt Taylor, ESA Rosetta project scientist.
“Today’s successful landing is undoubtedly the cherry on the icing of a 4 km-wide cake, but we’re also looking further ahead and onto the next stage of this ground-breaking mission, as we continue to follow the comet around the Sun for 13 months, watching as its activity changes and its surface evolves.”
While Philae begins its close-up study of the comet, Rosetta must manoeuvre from its post-separation path back into an orbit around the comet, eventually returning to a 20 km orbit on 6 December.
Next year, as the comet grows more active, Rosetta will need to step further back and fly unbound ‘orbits’, but dipping in briefly with daring flybys, some of which will bring it within just 8 km of the comet centre.
The comet will reach its closest distance to the Sun on 13 August 2015 at about 185 million km, roughly between the orbits of Earth and Mars. Rosetta will follow it throughout the remainder of 2015, as they head away from the Sun and activity begins to subside.
“It’s been an extremely long and hard journey to reach today’s once-in-a-lifetime event, but it was absolutely worthwhile. We look forward to the continued success of the great scientific endeavour that is the Rosetta mission as it promises to revolutionise our understanding of comets,” said Fred Jansen, ESA Rosetta mission manager.
Monday, 13 October 2014
Wednesday, 30 July 2014
Building ‘invisible’ materials with light brings science fiction cloaking devices one step closer to reality
Image Credit: Ventsislav Valev
A new method of building materials using light, developed by researchers at the University of Cambridge, could one day enable technologies that are often considered the realm of science fiction, such as invisibility cloaks and cloaking devices.This level of control opens up a wide range of potential practical applications
Although cloaked starships won’t be a reality for quite some time, the technique which researchers have developed for constructing materials with building blocks a few billionths of a metre across can be used to control the way that light flies through them, and works on large chunks all at once. Details are published in the journal Nature Communications.
The key to any sort of ‘invisibility’ effect lies in the way light interacts with a material. When light hits a surface, it is either absorbed or reflected, which is what enables us to see objects. However, by engineering materials at the nanoscale, it is possible to produce ‘metamaterials’: materials which can control the way in which light interacts with them. Light reflected by a metamaterial is refracted in the ‘wrong’ way, potentially rendering objects invisible, or making them appear as something else.
Metamaterials have a wide range of potential applications, including sensing and improving military stealth technology. However, before cloaking devices can become reality on a larger scale, researchers must determine how to make the right materials at the nanoscale, and using light is now shown to be an enormous help in such nano-construction.
The technique developed by the Cambridge team involves using unfocused laser light as billions of needles, stitching gold nanoparticles together into long strings, directly in water for the first time. These strings can then be stacked into layers one on top of the other, similar to Lego bricks. The method makes it possible to produce materials in much higher quantities than can be made through current techniques.
In order to make the strings, the researchers first used barrel-shaped molecules called cucurbiturils (CBs). The CBs act like miniature spacers, enabling a very high degree of control over the spacing between the nanoparticles, locking them in place.
In order to connect them electrically, the researchers needed to build a bridge between the nanoparticles. Conventional welding techniques would not be effective, as they cause the particles to melt. “It’s about finding a way to control that bridge between the nanoparticles,” said Dr Ventsislav Valev of the University’s Cavendish Laboratory, one of the authors of the paper. “Joining a few nanoparticles together is fine, but scaling that up is challenging.”
The key to controlling the bridges lies in the cucurbiturils: the precise spacing between the nanoparticles allows much more control over the process. When the laser is focused on the strings of particles in their CB scaffolds, it produces plasmons: ripples of electrons at the surfaces of conducting metals. These skipping electrons concentrate the light energy on atoms at the surface and join them to form bridges between the nanoparticles. Using ultrafast lasers results in billions of these bridges forming in rapid succession, threading the nanoparticles into long strings, which can be monitored in real time.
“We have controlled the dimensions in a way that hasn’t been possible before,” said Dr Valev, who worked with researchers from the Department of Chemistry, the Department of Materials Science & Metallurgy, and the Donostia International Physics Center in Spain on the project. “This level of control opens up a wide range of potential practical applications.”
- See more at: http://www.cam.ac.uk/research/news/building-invisible-materials-with-light#sthash.HbctmqrE.dpuf