Brightsurf Science News & Current Events

June 13, 2012
Pitcher plant uses power of the rain to trap prey
Carnivorous plants have developed a variety of unique mechanisms to trap their prey, and researchers have another to add to the list: a pitcher plant that uses the impact of rain drops to flick insects into the trap.

Sleep apnea linked to increased risk for carbohydrate craving among diabetics
Researchers are encouraging primary care physicians to screen for sleep apnea in patients with Type 2 diabetes after finding a high risk for sleep apnea among diabetics vs. non-diabetics in a clinic-based sample of 55 patients.

Timing, duration of biochemical bugle call critical for fighting viruses
Researchers at Washington University School of Medicine in St. Louis have identified the primary player of the biochemical bugle call that musters the body's defenders against viral infection.

Study shows people with Type 2 diabetes require ongoing and sustained clinical support
Research led by the University of Leicester concludes that people newly diagnosed with Type 2 diabetes need ongoing advice from GPs sustained over a number of years rather than a one-off session when they are first diagnosed.

Churches overlook women as donors, despite their growing wealth in US, Baylor scholar finds
Many churches are missing opportunities to involve Christian women in philanthropy, with ministry leaders too often speaking

Proposed testosterone testing of some female olympians challenged by Stanford scientists
Proposed Olympic policies for testing the testosterone levels of select female athletes could discriminate against women who may not meet traditional notions of femininity and distort the scientific evidence on the relationship between testosterone, sex and athletic performance, says a Stanford University School of Medicine bioethicist and her colleagues.

Symposium on reducing cardiovascular risks
On July 14, nationally renowned cardiovascular disease specialists will discuss the latest findings on how doctors and nurses can help their patients lower their risks of cardiac-related diseases.

Human Microbiome Project outlines powerful new methods for cataloging and analyzing microbes
New studies led by Harvard School of Public Health (HSPH) researchers have helped identify and analyze the vast human

London researchers discover novel mechanism involved in key immune response
A team of researchers at Lawson Health Research Institute and Western University have identified a novel way that a common virus, called adenovirus, causes disease.

How alert hospital employees improved hospital's MRSA infection rate
A better way to improve organizations using overlooked employee talent has taken a top award from a notable management group.

New energy source for future medical implants: Sugar
An implantable fuel cell built at MIT could power neural prosthetics that help patients regain control of limbs.

Bat bridges don't work
Wire bridges built to guide bats safely across busy roads simply do not work, University of Leeds researchers have confirmed.

Novel compounds to activate cannabinoid receptors wins award for Hebrew University researcher
Experimental work by a Hebrew University researcher involving stimulation of a cannabinoid receptor in the immune system has been shown to hold promise for the treatment of many neurological, inflammatory and other illnesses.

Inner ear may hold key to ancient primate behavior
CT scans of fossilized primate skulls or skull fragments from both the Old and New Worlds may shed light on how these extinct animals moved, especially for those species without any known remains, according to an international team of researchers.

Physical activity reduces compensatory weight gain after liposuction
Abdominal liposuction triggers a compensatory increase in visceral fat, which is correlated with cardiovascular disease, but this effect can be counteracted by physical activity, according to a recent study in the Journal of Clinical Endocrinology and Metabolism, a publication of the Endocrine Society.

1960s-era anti-cancer drug points to treatments for Lou Gehrig's disease
A long-used anti-cancer drug could be a starting point to develop new treatments for the incurable nerve disease known as Lou Gehrig's disease or amyotrophic lateral sclerosis (ALS), scientists are reporting.

Tracking MRSA in real time
Researchers have demonstrated that next-generation genome sequencing can provide clinically relevant data on bacterial transmission within a timescale that can influence infection control and patient management.

Youngest hip and thigh fracture patients heal just fine with single-leg casts
Challenging a longstanding practice of casting both legs in children with hip and thigh fractures, a new Johns Hopkins Children's Center study shows that such fractures heal just as well in single-leg casts, while giving children greater comfort and mobility.

Psychoeducational intervention changes patient attitudes on clinical trials participation
Seeking ways to change cancer patients' perceptions and negative attitudes towards clinical trials participation, researchers at Moffitt Cancer Center conducted a study offering two different kinds of intervention to two groups of adults with cancer who had not previously been asked to participate in clinical trials.

CPAP found to improve sexual function, satisfaction in men with sleep apnea
A new study found erectile dysfunction in 45 percent of men under age 60 suffering from sleep apnea.

Announcing the Human Microbiome Project Collection
The new PLoS Human Microbiome Project Collection encompasses genome sequencing research that shows, for the first time, reference data for microbes living with healthy adults.

Self-assembling nanocubes for next generation antennas and lenses
Researchers at the University of California, San Diego Jacobs School of Engineering have developed a technique that enables metallic nanocrystals to self-assemble into larger, complex materials for next-generation antennas and lenses.

Robot learns language through 'conversation' with people
A robot analogous to a child between six and 14 months old can develop rudimentary linguistic skills through interaction with a human participant, as reported June 13 in the open-access journal PLoS ONE.

Forsyth scientists define the bacteria that live in the mouth, throat and gut
For the first time, scientists have defined the bacteria that inhabit multiple sites along the healthy human digestive tract in a large number of individuals.

Mapping the healthy human microbiome
Human beings are ecosystems on two legs, each of us carrying enough microbes to outnumber our human cells by 10 to 1 and our genes by even more.

IU role in Human Microbiome Project exposes battle history between bacteria, viruses in human body
An Indiana University team of researchers has conducted the most in-depth and diverse genetic analysis of the defense systems that trillions of microorganisms in the human body use to fend off viruses.

Real-life scientific tale of the first 'electrified snail'
The latest episode in the American Chemical Society's award-winning Global Challenges/Chemistry Solutions podcast series describes the world's first

Genetic discovery will help fight diarrhea outbreaks
Researchers at the University of East Anglia have discovered unexpectedly large genetic differences between two similar species of the pathogenic Cryptosporidium parasite.

Scientists see new hope for restoring vision with stem cell help
Human-derived stem cells can spontaneously form the tissue that develops into the part of the eye that allows us to see, according to a study published by Cell Press in the fifth anniversary issue of the journal Cell Stem Cell.

Gladstone investigator Shinya Yamanaka receives Millennium Technology Award
Gladstone Institutes Senior Investigator Shinya Yamanaka, M.D., Ph.D., has won the Millennium Technology Award Grand Prize, the world's largest and most prominent technology award.

Researchers design new substances that might help fight Alzheimer's and Parkinson's disease
University of Granada researchers have tested melatonin analogues in rats that inhibit the enzyme nitric oxide synthase, which is involved in the development of the diseases referred above.

Ethics framework urged to manage conflicts of interest in medicine
A recent international study led by researchers from McGill University and the McGill University Health Centrer (MUHC) examines the complex and controversial interplay of conflicts of interest between physician experts, medicine and the pharmaceutical or medical device industry.

Berkeley Lab scientists help define the healthy human microbiome
A National Institutes of Health (NIH)-organized consortium that includes Berkeley Lab scientists has for the first time mapped the normal microbial make-up of humans.

More than 1 way to be healthy: Map of bacterial makeup of humans reveals microbial rare biosphere
Results of the NIH's Human Microbiome Project confirm concept of

Clarity begins at exome
In the June 13 issue of Science Translational Medicine, an international team led by researchers from the University of California, San Diego School of Medicine reports that the new technology of exome sequencing is not only a promising method for identifying disease-causing genes, but may also improve diagnoses and guide individual patient care.

Got mass? Princeton scientists observe electrons become both heavy and speedy
A Princeton University-led team of scientists has shown how electrons moving in certain solids can behave as though they are a thousand times more massive than free electrons, yet at the same time act as speedy superconductors.

Successful transplantation of tissue-engineered vein in a child offers hope for patients who lack suitable veins for dialysis or bypass surgery
The first biologically tissue-engineered vein grown from a patient's own stem cells has been successfully transplanted into a 10-year-old girl with portal vein obstruction, dramatically enhancing her quality of life.

Study finds Massachusetts health reform leads to increased inpatient surgical procedures
Researchers from Boston University Schools of Medicine and Public Health (BUSM, BUSPH), along with the VA Boston Healthcare System and Harvard Medical School, have found inpatient medical procedures increased more among non-elderly, lower- and medium- income populations, Hispanics and whites, after health care reform went into effect in Massachusetts.

Census of microbes in healthy humans reported
Trillions of microbes inhabit the human body, occupying virtually every nook and cranny.

NIST effort could improve high-tech medical scanners
A powerful color-based imaging technique is making the jump from remote sensing to the operating room.

'Magical state' of embryonic stem cells may help overcome hurdles to therapeutics
With their potential to treat a wide range of diseases and uncover fundamental processes that lead to those diseases, embryonic stem (ES) cells hold great promise for biomedical science.

Mindful multitasking: Meditation first can calm stress, aid concentration
Need to do some serious multitasking? Some training in meditation beforehand could make the work smoother and less stressful, new research from the UW Information School shows.

NIH Human Microbiome Project defines normal bacterial makeup of the body
For the first time, a consortium of researchers organized by the National Institutes of Health has mapped the normal microbial make-up of healthy humans, producing numerous insights and even a few surprises.

Researchers identify new group of proteins in the brains of Alzheimer's patients
Researchers from Boston University School of Medicine have identified a novel group of proteins that accumulate in the brains of patients with Alzheimer's disease.

Fruit flies reveal mechanism behind ALS-like disease
Studying how nerve cells send and receive messages, Johns Hopkins scientists have discovered new ways that genetic mutations can disrupt functions in neurons and lead to neurodegenerative disease, including amyotrophic lateral sclerosis (ALS).

Human Microbiome Project finds vast individuality in healthy human bacterial populations
In attempting to determine whether there were particular types of bacteria that were common, or

Increased use of hand held devices may call for new photo guidelines
Viewing Facebook and Flickr photos on a smart phone are becoming common practice.

NIST launches new website to educate industry about alternatives to mercury thermometers
As part of a larger effort to reduce the amount of mercury, a potent neurotoxin, in the environment, NIST has launched a new website to help industry scientists and engineers decide the best temperature measurement alternative for their purposes.

Brandeis University Heller center to manage $5 million of Walmart jobs fund
A Walmart grant will support summer employment opportunities for at-risk youth in major cities across the country.

Moffitt researcher, colleagues find success with new immune approach to fighting some cancers
A national research collaboration of senior researchers, including a researcher from Moffitt Cancer Center, has found that 20 to 25 percent of

'Hitchhiking' viral therapy deals a double blow to cancer
Scientists have shown how a promising viral therapy that delivers a double blow to cancer can sneak up on tumours undetected by hitching a ride on blood cells.

Juveniles build up physical -- but not mental -- tolerance for alcohol in Baylor study
Research into alcohol's effect on juvenile rats shows they have an ability to build up a physical, but not cognitive, tolerance over the short term -- a finding that could have implications for adolescent humans, according to Baylor University psychologists.

Obesity, depression found to be root causes of daytime sleepiness
Three new studies conclude that obesity and depression are the main culprits making Americans excessively sleepy while awake.

NASA's TRMM views forming tropical cyclone
System 94E and System 95E are low pressure areas located off the western coast of Mexico that are being watched by forecasters and by satellites.

Stanford marine biologist Barbara Block wins Rolex Award for Enterprise
Barbara Block, a professor at Stanford's Hopkins Marine Station, has been named a 2012 Rolex Laureate for her plan to monitor and protect large marine predators in the

Low energy levels could predict risk of hospitalisation for people with COPD
Reports of low energy levels or feelings of fatigue could be used to predict risk of hospitalization for people with chronic obstructive pulmonary disease, according to a new study published online ahead of print in the European Respiratory Journal.

'Extremely little' telescope discovers pair of odd planets
Though the KELT North telescope in southern Arizona carries a lens no more powerful than a high-end digital camera, it's just revealed the existence of two very unusual faraway planets.

Top cardiac electrophysiology congresses join forces
Europe's leading congresses in cardiac electrophysiology have agreed to hold a joint annual Congress during 2014-2017.

Georgia Tech startup SpherIngenics secures defense funding for cell delivery technology
Georgia Tech startup SpherIngenics is using microbead technology to produce protective capsules for the delivery of cell-based therapies.

Good news on using recycled sewage treatment plant water for irrigating crops
A new study eases concerns that irrigating crops with water released from sewage treatment plants -- an increasingly common practice in arid areas of the world -- fosters emergence of the antibiotic-resistant bacteria that cause thousands of serious infections each year.

Pitcher plant uses rain drops to capture prey
During heavy rain, the lid of Nepenthes gracilis pitchers acts like a springboard, catapulting insects that seek shelter on its underside directly into the fluid-filled pitcher, new research has found.

Bonobo genome completed
Max Planck scientists have completed the genome of the bonobo -- the final great ape to be sequenced.

Next-generation sequencing technology opens doors to discoveries
Discoveries unfathomable only a few years ago are reality today at the Texas AgriLife Genomics and Bioinformatics Service with the acquisition of next-generation sequencing technology on the Texas A&M University campus in College Station.

New software forecasts noise levels in the street
University of Granada researchers are working on the application of neural networks to develop a urban noise forecasting model, which would be very useful to people who is interested in buying a new house.

Western diet changes gut bacteria and triggers colitis in those at risk
Certain saturated fats that are common in the modern Western diet can initiate a chain of events leading to complex immune disorders in those with a genetic predisposition.

Putting parasites on the world map
Researchers have developed a new technique to identify hotspots of malaria parasite evolution and track the rise of malarial drug resistance, faster and more efficiently than ever before.

Tale of 3 segregations
Unlike most whites, blacks and Hispanics tend to have neighbors from other racial groups who are disproportionately likely to be poor.

Alien earths could form earlier than expected
Previous studies have shown that Jupiter-sized gas giants tend to form around stars containing more heavy elements than the sun.

Most older pedestrians are unable to cross the road in time
New research published in Age and Aging has compared the walking speed of the older population in the UK with the speed required to use a pedestrian crossing.

Key enzyme plays roles as both friend and foe to cancer
A molecule thought to limit cell proliferation also helps cancer cells survive during initial tumor formation and when the wayward cells spread to other organs in the body, researchers at the University of Illinois at Chicago College of Medicine have found.

New research showing how real-life exposure to violence disrupts a child's sleep habits
Violence in a child's world impacts sleep, new research shows.

ESMO 2012 Congress: A path for medical oncology innovations
More than 17,000 participants from over 120 different countries are coming to Vienna for the 37th congress of the European Society for Medical Oncology, including oncology professionals, healthcare policy makers, patient groups, pharmaceutical industry, cancer foundations and representatives of international media.

Hindcasting helps scientists improve forecasts for life on Earth
Some 70 UC Berkeley scientists have launched a unique program, the Berkeley Initiative in Global Change Biology, to use hindcasting --

The science of training and development in organizations: What really matters, what really works
Each year in the United States about $135 billion is spent in training employees -- but those billions do not always improve the workplace because the skills often do not transfer to the actual job.

Virtual sailing gives competitors the edge
Newcastle University's Yacht and Superyacht Research Group show how virtual simulation can be used to accurately predict how a yacht will behave during a race.

Epileptic seizures linked to common childhood viral infection
Investigators report that a common, treatable virus was found in a third of infants with prolonged seizures.

Forsyth Team collaborates with Human Microbiome Project
Forsyth scientists have made a significant contribution to the Human Microbiome Project, an initiative which has defined the normal bacterial makeup of the human body for the first time in history.

New research to improve protection and recovery from major floods
As parts of the UK suffer further flooding with more heavy rain forecast, three research projects funded by the Engineering and Physical Sciences Research Council could radically change the way we prepare for and respond to floods, mitigating future risks.

Good news: Fewer maternal and child deaths
Since 1990, annual maternal deaths have declined by almost one half and the deaths of young children have declined from 12 million to 7.6 million in 2010.

Early learning about spatial relationships boosts understanding of numbers
Children who are skilled in understanding how shapes fit together to make recognizable objects also have an advantage when it comes to learning the number line and solving math problems.

UMass Amherst network researchers help lay groundwork for White House's 'US Ignite'
Scientists at the University of Massachusetts Amherst are among those from nearly two dozen institutions tapped by NSF to take part.

GAVI boosts global response to measles outbreaks
Seeking to address the devastating resurgence of measles, the GAVI Alliance will provide up to an additional $162 million to control and prevent outbreaks in developing countries.

MindSpec develops Autism Quiz app
To spread public knowledge of autism research, MindSpec has created a new Autism Quiz social media app which allows the general public to test autism knowledge and share facts about autism with friends.

Is it constitutional for states to regulate pharmaceutical gifts and meals to doctors?
Marcia Boumil of Tufts University School of Medicine examines state laws regulating pharmaceutical gifts to doctors and finds that their constitutionality may be in question in light of a 2011 US Supreme Court case from Vermont concerning data mining.

No evidence for 'knots' in space
Theories of the primordial universe predict the existence of knots in the fabric of space -- known as cosmic textures -- which could be identified by looking at light from the cosmic microwave background, the relic radiation left over from the Big Bang.

Sending sexually explicit photos by cell phone -- more common among teens than you might think
A significant number of teenagers are sending and receiving sexually explicit cell phone photos, often with little awareness of the possible psychological, interpersonal, and sometimes legal consequences of doing so.

Study finds socioeconomic status linked to weight gain and risk of obesity in African-American women
Socioeconomic status across one's lifetime is related to weight gain and risk of obesity in African-American women, according to a new study led by researchers from the Slone Epidemiology Center at Boston University.

NSF Leadership in Discovery and Innovation sparks White House US Ignite Initiative
The National Science Foundation (NSF) announced that it will serve as the lead federal agency for a White House Initiative called US Ignite, which aims to realize the potential of fast, open, next-generation networks.

Predicting post-traumatic stress disorder before it happens
Using brain imaging and function techniques, Professor Talma Hendler and Prof.

New trial drug a 'Trojan Horse' attacking pancreatic cancer
An investigational drug that acts like a Trojan Horse to deliver cancer killing agents for pancreatic cancer is being studied at the Virginia G.

Anxious mice make lousy dads: study
Normally, male California mice are surprisingly doting fathers, but new research published in the journal Physiological and Biochemical Zoology suggests that high anxiety can turn these good dads bad.

Citizen scientists to document biodiversity with high-resolution imagery during summer solstice
A high-resolution image of a palm tree in Brazil, which under close examination shows bees, wasps and flies feasting on nectars and pollens, was the top jury selection among the images captured during last December's Nearby Nature GigaBlitz.

Consortium of scientists maps the human body's bacterial ecosystem
Scientists at the Gladstone Institutes today are announcing their role in an unprecedented collaboration organized by the National Institutes of Health, which used groundbreaking methods to vastly improve our understanding of bacteria that reside in and on the human body.

New technology set to 'revolutionize' the identification of disaster victims
Scientists at Queen Mary, University of London have created new software which will enable experts to be better equipped to assess people's teeth and accurately estimate their age.

Videogamers no better at talking while driving
No matter how much time you've spent training your brain to multitask by playing

UCSB scientists synthesize first genetically evolved semiconductor material
In the not-too-distant future, scientists may be able to use DNA to grow their own specialized materials, thanks to the concept of directed evolution.

Divide the Antarctic to protect native species, propose experts
An international team of scientists have published the first continent-wide assessment of the Antarctic's biogeography, and propose that the landmass should be divided into 15 distinct conservation regions to protect the continent from invasive alien species.

Clinical trial of human hookworm vaccine begins at Children's National Medical Center
Today, the Sabin Vaccine Institute, in partnership with the George Washington University and the Children's National Medical Center, began vaccinating participants for a Phase 1 clinical trial of a novel human hookworm vaccine.

New drug-screening method yields long-sought anti-HIV compounds
Scientists at the Scripps Research Institute have used a powerful new chemical-screening method to find compounds that inhibit the activity of human immunodeficiency virus (HIV), the virus that causes AIDS.

Folic acid intake during early pregnancy associated with reduced risk of autism in offspring
A new study by researchers at the UC Davis MIND Institute suggests that women who consume the recommended daily dosage of folic acid, the synthetic form of folate or vitamin B-9, during the first month of pregnancy may have a reduced risk of having a child with autism.

Bacterium signals plant to open up and let friends in
Researchers have identified the set of tools an infectious microbe uses to persuade a plant to open the windows and let the bug and all of its friends inside.

Productivity gains from health IT must await bigger health system changes
Productivity gains that can be achieved by widely adopting health information technology are likely to come from the re-engineering of health care and may require new measurement tools to accurately gauge their impact, according to a new analysis from RAND Corporation researchers.

Researchers find new cause of cardiac damage after heart attack in type 1 diabetes
Scientists have been puzzled by the fact that after people with type 1 diabetes have a heart attack, their long-term chance of suffering even more heart damage skyrockets.

Web-based tool helps parents improve on kids' asthma treatment
New study results from Seattle Children's Research Institute found that parents who used an interactive website to track their child's usage of asthma controller medications, improved compliance with asthma controller medication use.

Where we split from sharks: Common ancestor comes into focus
The common ancestor of all jawed vertebrates on Earth resembled a shark, according to a new analysis of the braincase of a 290-million-year-old fossil fish that has long puzzled paleontologists.

Studies show sleep times influenced by race, ethnicity and country of origin
Two new studies report sleep disparities among Americans based on racial and ethnic background.

Scripps research scientists show lack of single protein results in persistent viral infection
Scientists from the Scripps Research Institute have shown a single protein can make the difference between an infection clearing out of the body or persisting for life.

Global climate change: Underestimated impact of sea-level rise on habitat loss?
Global climate change is expected to cause sea-level rise of approximately 1-2 meters within this century.

Hysterectomy may lead to arterial stiffening in postmenopausal women
Estrogen-deficient, postmenopausal women who have had their uterus removed appear to have stiffer arteries compared to women who have not had hysterectomies, according to the University of Colorado School of Medicine.

Planets can form around different types of stars
It had previously been thought that planets were more likely to form around a star if the star had a high content of heavier elements.

NuSTAR opens out-of-this-world view thanks to Livermore Lab technology
NuSTAR will allow researchers to observe a new class of objects in space, called extreme objects, which have never been seen.

Psychological distress associated with division of domestic work
Women are more likely than men to be responsible for the majority of domestic work in a household, which can lead to higher psychological distress, and new research shows that this correlation is further increased by perceived socioeconomic and gender inequality in the relationship, according to a study published June 13 in the open-access journal PLoS ONE.

NTU researchers study little mighty creature for scientific breakthrough
A blueprint derived from studying the mantis shrimp's club-like appendages could lead to making ceramics -- today's preferred material for medical implants and military body armor -- many times stronger.

Big uncertainties in the global water budget
No life without water. Catastrophes like droughts or strong rains reflect our dependence on the water cycle and climate system.

$5M pledge to further research at Molly and Doug Barnes Vision Institute
University of Houston College of Optometry alumnus Dr. Doug Barnes and his wife, Molly, have made a $5 million pledge to the University of Houston.

Stanford researchers discover the African cichlid's noisy courtship ritual
Stanford researchers have found that male African cichlids vocalize during courtship, and that females' sensitivity to these sounds increases when they are ready to mate.

Caregiver's health is strong predictor of orphan's health
The health of a caregiver is the most important predictor of orphan health, according to a new Duke University study that spans five less-wealthy nations in Africa and Asia.

Ancient effect harnessed to produce electricity from waste heat
A phenomenon first observed by an ancient Greek philosopher 2,300 years ago has become the basis for a new device designed to harvest the enormous amounts of energy wasted as heat each year to produce electricity.

Advanced cancers destined to recur after treatment with single drugs that 'target' tumor cells
Targeted cancer cell therapies using man-made proteins dramatically shrink many tumors in the first few months of treatment, but new research from Johns Hopkins scientists finds why the cells all too often become resistant, the treatment stops working, and the disease returns.

North-East Passage soon free from ice again?
The North-East Passage, the sea route along the North coast of Russia, is expected to be free of ice early again this summer.

Innovations in anticoagulation for stroke prevention
New scientific findings in anticoagulation for stroke prevention are paving the way for updates to the European Society of Cardiology guidelines for the management of atrial fibrillation.

Researchers determine pathway for origin of most common form of brain and spinal cord tumor
Johns Hopkins researchers say they have discovered one of the most important cellular mechanisms driving the growth and progression of meningioma, the most common form of brain and spinal cord tumor.

Normal bacterial makeup has huge implications for health, says CU professor
For the first time a consortium of researchers organized by the National Institutes of Health, including a University of Colorado Boulder professor, has mapped the normal microbial makeup of healthy humans.

'No-sleep energy bugs' drain smartphone batteries
Researchers have proposed a method to automatically detect a new class of software glitches in smartphones called

Book a flight on 'Air Algae?'
When the smell of french fries wafts through the airplane cabin, is it from that guy in 24D scarfing down a fast-food meal -- or the jet engines? is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to