Now, a theoretical study by MIT researchers suggests that small changes in roadway paving practices could reduce that efficiency loss, potentially eliminating a half-percent of the total greenhouse gas emissions from the transportation sector, at little to no cost.

The findings are detailed in a paper in the journal Transportation Research Record, by MIT postdoc Hessam Azarijafari, research scientist Jeremy Gregory, and principal research scientist in the Materials Research Laboratory Randolph Kirchain. The study examined state-by-state data on climate conditions, road lengths, materials properties, and road usage, and modeled different scenarios for pavement resurfacing practices.

They found that that one key to improving mileage efficiency is to make pavements that are stiffer, Kirchain explains. That reduces the amount of deflection, which reduces wear on the road but also reduces the slightly uphill motion the vehicle constantly has to make to rise out of its own depression in the road.

“When we as individuals walk on pavements, they seem like perfectly rigid things. They’re not responding to us,” he says. “But for trucks, that is not the case. There is enough of a deflection in that surface that some amount of energy is expended to overcome the little divot that you create as you drive along.” He likens it to the difference between walking on a hard surface versus walking on sand, which takes more effort because you sink in with each step.

Looking to the future, Kirchain says that while projections show a slight decline in passenger car travel over coming decades, they show an increase in truck travel for freight delivery — the kind where pavement deflection could be a factor in overall efficiency.

There are several ways to make roadways stiffer, the researchers say. One way is to add a very small amount of synthetic fibers or carbon nanotubes to the mix when laying asphalt. Just a tenth of a percent of the inexpensive material could dramatically improve its stiffness, they say. Another way of increasing rigidity is simply to adjust the grading of the different sizes of aggregate used in the mix, to allow for a denser overall mix with more rock and less binder.

“If there are high quality local materials available” to use in the asphalt or concrete mix, “we can use them to improve the stiffness, or we can just adjust the grading of the aggregates that we are using for these pavements,” says Azarijafari. And adding different fibers is “very inexpensive compared to the total cost of the mixture, but it can change the stiffness properties of the mixture significantly.”

Yet another way is to switch from asphalt pavement surfaces to concrete, which has a higher initial cost but is more durable, leading to equal or lower total lifecycle costs. Many road surfaces in northern U.S. states already use concrete, but asphalt is more prevalent in the south. There, it makes even more of a difference, because asphalt is especially subject to deflection in hot weather, whereas concrete surfaces are relatively unaffected by heat. Just upgrading the road surfaces in Texas alone, the study showed, could make a significant impact because of the state’s large network of asphalt roads and its high temperatures.

Kirchain, who is co-director of MIT’s Concrete Sustainability Hub, says that in carrying out this study, the team is “trying to understand what are some of the systemic environmental and economic impacts that are associated with a change to the use of concrete in particular in the pavement system.”

Even though the effects of pavement deflection may seem tiny, he says, “when you take into account the fact that the pavement is going to be there, with thousands of cars driving over it every day, for dozens of years, so a small effect on each one of those vehicles adds up to a significant amount of emissions over the years.” For purposes of this study, they looked at total emissions over the next 50 years and considered the reductions that would be achieved by improving anywhere from 2 percent of road surfaces to 10 percent each year.

With a 10 percent improvement rate, they calculated, a total of 440 megatons of carbon dioxide-equivalent emissions would be avoided over the 50 years, which is about 0.5 percent of total transportation-related emissions for this period.

The proposal may face some challenges, because changing the mix of materials in asphalt might affect its workability in the field, perhaps requiring adjustments to the equipment used. “That change in the field processing would have some cost to it as well,” Kirchain says.

But overall, implementing such changes could in many cases be as simple as changing the specifications required by state or local highway authorities. “These kinds of effects could be considered as part of the performance that’s trying to be managed,” Kirchain says. “It largely would be a choice from the state’s perspective, that either fuel use or climate impact would be something that would be included in the management, as opposed to just the surface performance of the system.”

The international trial — known as CAPP2 — involved patients with Lynch syndrome from around the world and revealed that two aspirins a day, for an average of two and a half years, reduced the rate of bowel cancer by half.

The study, led by experts at the Universities of Newcastle and Leeds, UK, published in The Lancet today, is a planned double blind 10 year follow-up, supplemented in more than half of recruits with comprehensive national cancer registry data for up to 20 years.

Supports national guidance

The findings of the study further strengthens the National Institute for Health and Care Excellence (NICE) recommendation on taking daily aspirin for those at high risk and supports wider use of aspirin to prevent cancer.

Based on the preliminary five year data from the CAPP2 trial, NICE recommended that aspirin should be offered for the prevention of bowel cancer in adults with Lynch syndrome.

Professor Sir John Burn, from Newcastle University and Newcastle Hospitals NHS Foundation Trust, who led the research, said the new findings further support this important guidance.

He said: “I had an idea 30 years ago that people with a genetic predisposition to colon cancer could help us to test whether aspirin really could reduce the risk of cancer.

“Patients with Lynch syndrome are high risk and this offered statistical power to use cancer as an endpoint — they are like the canaries in the mine who warned the miners that there was gas.

“It took a long time to start the trial and to recruit enough people in 16 countries, but this study has finally given us an answer.

“Two aspirins a day for a couple of years gives protection that lasts more than 10 years and the statistical analysis has become much stronger with time.

“For people at high cancer risk, the benefits are clear — aspirin works. Our new international trial, CaPP3, will see if smaller doses work just as well.”

Findings showed that when all original recruits were included in the study, those on aspirin had 42% fewer colon cancers. Among those who took the aspirin for a full two years, there were 50% fewer colon cancers.

The study involved 861 patients with Lynch syndrome, which affects about one in 200 people in the population. These people have a genetic problem with DNA repair, making them at much higher risk of cancers such as bowel and womb.

A group of 427 were randomised to aspirin continuously for two years and 434 were allocated to a placebo and then they were all followed for 10 years. Out of those given two aspirins each day (600mg) there were 18 fewer colon cancers, representing a drop of 42.6%.

When all 163 Lynch syndrome cancers are included in the analysis — such as cancer of the endometrium or womb — there was an overall reduced risk of cancer of 24% in those taking aspirin, or 37% in those who took aspirin for the full two years.

Historic background

Between 1999 and 2005 participants began either taking two aspirins every day for two years or a placebo.

At the end of the treatment stage in 2007 there was no overall difference between those who had taken aspirin and those who had not. However, the research team anticipated a longer term effect and designed the study for continued follow-up.

By 2010 there had been 19 new bowel cancers among those who had received aspirin and 34 among those on placebo. The incidence of cancer among the group who had taken aspirin had halved — and the effect began to be seen five years after patients starting taking the aspirin.

Professor Sir John said: “Aspirin has a major preventative effect on cancer but this doesn’t become apparent until at least four years later. With the help of these dedicated volunteers we have learned something of value to us all.

“Before anyone begins to take aspirin on a regular basis they should consult their doctor first as aspirin is known to bring with it a risk of stomach complaints, including ulcers and bleeding.

“However, if there is a strong family history of cancer then people may want to weigh up the cost and health benefits of taking aspirin for at least two years.”

The team are now leading a new international trial, CaPP3, with more than 1,800 people with Lynch syndrome enrolled to look at whether smaller, safer doses of aspirin can be used to help reduce the cancer risk.

The research is funded by Cancer Research UK, NIHR, Bayer Pharma AG and the Barbour Foundation.

Ability to ‘inhibit’ impulses

Researchers of the study, which will be published in a forthcoming issue of the journal Personality Disorders: Theory, Research, and Treatment, separated psychotic individuals into two groups: “successful” vs. “unsuccessful”. This was based on their life trajectories (the path in life one chooses) and outcomes. 

The successful psychopath, for instance, is a CEO or lawyer, whereas an unsuccessful psychopath, who may possess the same traits, is someone who has been convicted of a crime.

Researchers incorporated a compensatory model of “successful” psychopathy into their study. This model theorises that relatively successful psychopaths develop greater conscientious traits, which ultimately leads to an inhibition of heightened antisocial impulses. 

“The compensatory model posits that people higher in certain psychopathic traits (such as grandiosity and manipulation) are able to compensate for and overcome, to some extent, their antisocial impulses via increases in trait conscientiousness, specifically impulse control,” said lead author Emily Lasko, a doctoral candidate in the Department of Psychology in the College of Humanities and Sciences.

Control and aggression

Data from around 1 354 serious juvenile offenders in Arizona and Pennsylvania in the US were collected, and the research team used this to test the model. Among the offenders who re-offended less, termed as the “successful” offenders by the researchers, an especially magnified link between steep increases in general inhibitory control, as well as the inhibition of aggression over time was observed. 

“Psychopathic individuals are very prone to engaging in antisocial behaviours, but what our findings suggest is that some may actually be better able to inhibit these impulses than others,” Lasko said, adding: “Although we don’t know exactly what precipitates this increase in conscientious impulse control over time, we do know that this does occur for individuals high in certain psychopathy traits who have been relatively more ‘successful’ than their peers.”

How the study’s findings may help

The researchers’ results, therefore, support the compensatory model of “successful” psychopathy and run contradictory to other existing psychopathy models, Lasko explained: “Our findings… focus more on the strengths or ‘surpluses’ associated with psychopathy rather than just deficits. Psychopathy is not a personality trait simply composed of deficits – there are many forms that it can take.”

Lasko further explained that the team hopes these findings could be useful within clinical and forensic settings, especially in developing effective and early intervention strategies that could potentially identify the strengths of psychopathic individuals, and ultimately deter any future antisocial behaviour.

European animal and human mammoth ivory carvings dated to 40-38 ka are our earliest examples of prehistoric humans three-dimensionally representing the world around them — though due to a lack of evidence, it’s unclear when this type of three-dimensional representation became part of the cultural repertoire of prehistoric groups around the rest of the world. In this study, Li and colleagues describe the remarkable discovery of a small standing bird carving from the Paleolithic site of Lingjing, in Henan, China, that sheds further light on humanity’s earliest three-dimensional art.

During Li’s initial excavation at Lingjing in 2005, he uncovered eleven distinct stratified layers ranging in age from 120,000 years ago to the Bronze Age — and found that most of the fifth layer had been removed during a well-digging operation in 1958. However, the refuse heap from the well’s creation was still intact and remained nearby. After sifting through the sediment in the refuse heap, the authors discovered black flint identical to (and only found in) what remained of Layer 5 at the dig site. They also uncovered several artifacts, including pottery sherds, burned animal remains, and the bird figurine, which is carved from bone and shaped like a songbird on a pedestal.

Using radiocarbon dating on the uncovered burned animal remains (including one bone with anthropogenic gouging marks also observed on the bird carving), the authors were able to estimate the age of the bird figurine and associated bone material to be approximately 13.4-13.2 ka cal BP. Based on evidence from other Northern Chinese sites of similar age, this suggests that hunter-gatherers with stone tool technologies occupied Lingjing and created the bird carving during this time.

Bird representations are a theme in Chinese Neolithic art, with the oldest example a jade songbird dated to approximately 5 ka BP. This Paleolithic bone bird figurine from Lingjing predates previously known instances from this region by almost 8,500 years, and has several technological and stylistic elements distinguishing it from contemporaneous representations of birdlike creatures from Western Europe and Siberia (such as the pedestal on which the Lingjing bird is perched). Though more examples of Paleolithic carving art are needed to confirm this possibility, the Lingjing bird figurine suggests the presence of a longstanding artistic tradition specific to East Asia, with origins much earlier in the Paleolithic.

The authors add: “This discovery identifies an original artistic tradition and pushes back by more than 8,500 years the representation of birds in Chinese art. The figurine differs technologically and stylistically from other specimens found in Western Europe and Siberia, and it could be the missing link tracing the origin of Chinese statuary back to the Palaeolithic period.”

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