From 2012 to 2019, the researchers monitored elephants’ movements through six wildlife corridors using of motion-detected camera traps in two different human-dominated landscapes: the townships of Kasane and Kazungula, and the farming villages of the Chobe Enclave, both located in the Chobe District.

The study shows that various land-use seemingly affects when elephants use wildlife corridors on an hourly basis. Elephants in agricultural areas largely moved through the corridors predominantly nocturnally, when humans are less active, compared to the urban corridors, where humans and elephants actively mostly overlap.

‘This is the first study of this type that takes an in-depth look at comparing how varying land-use affects elephant movements and their use of wildlife corridors,’ states lead author Tempe Adams of EWB. Increasing human development and changes in land-use restrict wildlife’s access to resources. It also increases competition and conflict between animals and people. This is one of the largest conservation challenges facing the future of elephants in both Africa and Asia. The designation and maintenance of wildlife corridors is a fundamental wildlife management tool to allow both development and conservation to continue.

‘This was a great opportunity to link our work on examining human pressures on biodiversity at Radboud University with the conservation work being done by Elephants Without Borders,’ says Marlee Stevens, assistant professor at the ?Department of Environmental Science of Radboud University and one of the authors of the paper. ‘Our results show that elephants alter their behaviour in human-modified landscapes, but their response varies depending on the human disturbance.’

The study highlights the need to consider wildlife daily activity patterns in and around cities, towns, and farming areas, for conservation and environmental management planning. ‘What is truly remarkable is that we found elephants do not perceive all human development the same way, but they are adjusting their behaviours to adapt to the variations and human pressure,’ says Adams. ‘It also further highlights the need for transparent documentation of human pressure within and around protected wildlife areas, which is critical to assist in the conservation of species’.

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Materials provided by Radboud University Nijmegen. Note: Content may be edited for style and length.

In their analysis researchers from the University of East Anglia (UEA), the French Centre National de la Recherche Scientifique (CNRS) and the OACIS initiative of the Prince Albert II of Monaco Foundation, challenge the widely held view that restoring areas such as mangroves, saltmarsh and seagrass can remove large amounts of carbon dioxide (CO₂) from the atmosphere.

The findings of their review, published today in the journal Frontiers in Climate, identify seven reasons why carbon accounting for coastal ecosystems is not only extremely challenging but risky.

These include the high variability in carbon burial rates, vulnerability to future climate change, and fluxes of methane and nitrous oxide. The authors, who also looked at information on restoration costs, warn that extra measurements can reduce these risks, but would mean much higher costs.

However, they stress that blue carbon habitats should still be protected and, where possible, restored, as they have benefits for climate adaptation, coastal protection, food provision and biodiversity conservation.

Lead author Dr Phil Williamson, honorary reader in UEA’s School of Environmental Sciences, said: “We have looked into the processes involved in carbon removal and there are just too many uncertainties. The expected climate benefits from blue carbon ecosystem restoration may be achieved, yet it seems more likely they will fall seriously short.

“If you want to have extra carbon removal, you need extra habitat, and the scope for restoration is limited. Many of these sites have been built on, for coastal settlement, tourism and port development.

“Nevertheless, we believe that every effort should be made to halt, and wherever possible reverse, the worldwide loss of coastal vegetation. That’s because blue carbon habitats are more than carbon stores — they also provide storm protection, support biodiversity and fisheries, and improve water quality.”

The sediments beneath mangrove forests, tidal saltmarshes and seagrass meadows are rich in organic carbon, accumulated and stored over many hundreds of years.

Many recent studies and reviews have favourably identified the potential for these coastal blue carbon ecosystems to provide a natural climate solution in two ways: by conservation, reducing the greenhouse gas emissions arising from the loss and degradation of such habitats, and by restoration, to increase carbon dioxide drawdown and its long-term storage.

This new review focuses on the latter, assessing the feasibility of achieving quantified and secure carbon removal (negative emissions) through the restoration of coastal vegetation.

Increasingly businesses and states have pledged to offset their emissions by restoring these ecosystems through carbon credits, assuming reliable knowledge on how much CO₂ they will remove in future from the atmosphere.

However, Dr Williamson and co-author Prof Jean-Pierre Gattuso, of CNRS and the OACIS initiative of the Prince Albert II of Monaco Foundation, say the policy problem is more subtle. That is, CO₂ removal using coastal blue carbon restoration has questionable cost-effectiveness when considered only as a climate mitigation action, either for carbon-offsetting or for inclusion in countries’ Nationally Determined Contributions, which set out their efforts to reduce emissions and adapt to the impacts of climate change under the Paris Agreement.

“If we use these ecosystems for carbon offsets in a major way, expecting that they would remove up to, say, 100 gigatonnes of carbon dioxide over the period 2025-2100, but find they only remove 10 or maybe just one gigatonne of CO₂, then climate tipping points could be crossed, with really serious consequences,” said Dr Williamson.

“If, however, such ecosystems are restored to protect biodiversity, and we find that they also remove several gigatonnes of CO₂, then that would be a bonus, assuming other means are used for climate mitigation.

“Restoration should therefore be in addition to, not as a substitute for, near-total emission reductions. Where coastal blue ecosystems restoration projects are carried out primarily for carbon removal, they need to include comprehensive long-term monitoring to verify that the intended climate benefits are being achieved.”

Prof Gattuso said: “Many important issues relating to the measurement of carbon fluxes and storage have yet to be resolved, affecting certification and resulting in potential over-crediting.

“The restoration of coastal blue carbon ecosystems is nevertheless highly advantageous for climate adaptation, coastal protection, food provision and biodiversity conservation. Such action can therefore be societally justified in very many circumstances, based on the multiple benefits that such habitats provide at the local level.”

Our cells are subject to mechanical forces exerted on a microscopic scale, triggering biological signals essential to many cell processes involved in the normal functioning of our body or in the development of diseases.

For example, the feeling of touch is partly conditional on the application of mechanical forces on specific cell receptors (the discovery of which was this year rewarded by the Nobel Prize in Physiology or Medicine). In addition to touch, these receptors that are sensitive to mechanical forces (known as mechanoreceptors) enable the regulation of other key biological processes such as blood vessel constriction, pain perception, breathing or even the detection of sound waves in the ear, etc.

The dysfunction of this cellular mechanosensitivity is involved in many diseases — for example, cancer: cancer cells migrate within the body by sounding and constantly adapting to the mechanical properties of their microenvironment. Such adaptation is only possible because specific forces are detected by mechanoreceptors that transmit the information to the cell cytoskeleton.

At present, our knowledge of these molecular mechanisms involved in cell mechanosensitivity is still very limited. Several technologies are already available to apply controlled forces and study these mechanisms, but they have a number of limitations. In particular, they are very costly and do not allow us to study several cell receptors at a time, which makes their use very time-consuming if we want to collect a lot of data.

DNA origami structures

In order to propose an alternative, the research team led by Inserm researcher Gaëtan Bellot at the Structural Biology Center (Inserm/CNRS/Université de Montpellier) decided to use the DNA origami method. This enables the self-assembly of 3D nanostructures in a pre-defined form using the DNA molecule as construction material. Over the last ten years, the technique has allowed major advances in the field of nanotechnology.

This enabled the researchers to design a “nano-robot” composed of three DNA origami structures. Of nanometric size, it is therefore compatible with the size of a human cell. It makes it possible for the first time to apply and control a force with a resolution of 1 piconewton, namely one trillionth of a Newton — with 1 Newton corresponding to the force of a finger clicking on a pen. This is the first time that a human-made, self-assembled DNA-based object can apply force with this accuracy.

The team began by coupling the robot with a molecule that recognizes a mechanoreceptor. This made it possible to direct the robot to some of our cells and specifically apply forces to targeted mechanoreceptors localized on the surface of the cells in order to activate them.

Such a tool is very valuable for basic research, as it could be used to better understand the molecular mechanisms involved in cell mechanosensitivity and discover new cell receptors sensitive to mechanical forces. Thanks to the robot, the scientists will also be able to study more precisely at what moment, when applying force, key signaling pathways for many biological and pathological processes are activated at cell level.

“The design of a robot enabling the in vitro and in vivo application of piconewton forces meets a growing demand in the scientific community and represents a major technological advance. However, the biocompatibility of the robot can be considered both an advantage for in vivo applications but may also represent a weakness with sensitivity to enzymes that can degrade DNA. So our next step will be to study how we can modify the surface of the robot so that it is less sensitive to the action of enzymes. We will also try to find other modes of activation of our robot using, for example, a magnetic field,” emphasizes Bellot.

[1] Also contributed to this research: the Institute of Functional Genomics (CNRS/Inserm/Université de Montpellier), the Max Mousseron Biomolecules Institute (CNRS/Université de Montpellier/ENSCM), the Paul Pascal Research Center (CNRS/Université de Bordeaux) and the Physiology and Experimental Medicine: Heart-Muscles laboratory (CNRS/Inserm/Université de Montpellier).

About 150,000 nontraumatic amputations occur annually, according to the 2021 American Heart Association policy statement: Reducing Nontraumatic Lower-Extremity Amputations by 20% by 2030: Time to Get to Our Feet. Between 8 and 10 million people in the United States have PAD. The condition disproportionately affects Black people, American Indian people and those of low socioeconomic status.

The condition occurs when the arteries that transport blood from the heart throughout the body narrow, reducing blood and oxygen flow. It usually affects the legs and feet causing symptoms while walking, such as cramping, weakness, fatigue, aching and pain or discomfort that subside within 10 minutes of rest. Previous research found that walking for exercise, particularly on a treadmill while supervised by a staff member, improves walking ability and walking distance among people with PAD. What remained unclear were the potential effects of walking at a pace that induced symptoms such as leg pain on speed, strength and balance.

This study examined the effects of home-based walking for exercise among 264 people with PAD who were participating in a randomized clinical trial, called the Low-Intensity Exercise Intervention in PAD (LITE), which included 305 people overall. From September 2015 to December 2019, participants enrolled in the LITE study at four U.S. medical centers (Northwestern University, Tulane University, University of Minnesota and University of Pittsburgh). Their average age was 69 years, 48% were women and 61% were Black adults.

Researchers randomly assigned participants to one of three groups for 12 months. The first group (38%) walked at home at a comfortable pace; the second group (41%) walked at home at a pace that induced leg symptoms; while the third group (21%) did not walk for exercise. Both walking exercise groups wore an ActiGraph, a device that monitored the intensity of their walking and the time walked.

Personalized thresholds for the ActiGraph intensity that corresponded to walking for exercise at a pace that induced leg symptoms (high intensity) and that corresponded to walking for exercise at a comfortable pace without leg symptoms (low intensity) were defined for each individual randomized to an exercise intervention. Participants randomized to exercise wore their ActiGraph device during walking exercise activity and uploaded data on exercise frequency, intensity and duration to the study website.

At the study’s start and at 6 and 12 months, participants completed three tests of leg function: walking speed over a four-meter distance (13 feet) at usual pace, walking speed over a four-meter distance at fastest pace and the short physical performance battery (SPPB) consisting of four-meter walking velocity at usual pace, a standing balance test and the time for five repeated chair rises.

The key findings were:

• At six months, participants whose walking pace induced leg pain or discomfort walked 11 feet per minute faster, and at 12 months, they walked more than 16 feet per minute faster than participants whose walking pace did not induce leg pain or discomfort. Compared to non-exercisers, participants in the group that walked for exercise at a pace inducing leg pain or discomfort walked nearly 13 feet per minute faster at six months, however, this increase was not statistically significant at 12 months.
• At 12 months, people who walked for exercise with leg pain or discomfort scored almost 1 point higher on the sum of the three leg function tests (the short physical performance battery), out of a total of 13 points (0-12), compared to people who walked at a comfortable pace with no leg pain. For those walking for exercise at a comfortable pace, there was no improvement in walking speed at six months or 12 months compared to non-exercisers.

“We were surprised by the results because walking for exercise at a pace that induces pain in the legs among people with PAD has been thought to be associated with damage to leg muscles,” said senior study author Mary M. McDermott, M.D., the Jeremiah Stamler Professor of Medicine in the division of general internal medicine and geriatric medicine and of preventive medicine at Northwestern University’s Feinberg School of Medicine in Chicago. “Based on these results, clinicians should advise patients to walk for exercise at a pace that induces leg discomfort, instead of at a comfortable pace without pain.”

This underscores the benefits of walking for exercise at a pace that induces leg pain or discomfort. “This finding is consistent with “no pain, no gain” with regard to walking exercise in PAD,” McDermott said.

“Exercise that induces leg pain is beneficial, though difficult,” McDermott said. “We now are working to identify interventions that can make the higher intensity exercise easier — and still beneficial — for people with PAD.”

It is important to note that study participants walked at home, so the results may not apply to walking on a treadmill in the presence of a health professional, which is the standard of care and first line therapy according to clinical practice guidelines. In addition, the outcomes in this report were not pre-specified outcomes for this clinical trial. Therefore, these findings must be confirmed in future research.

In May 2022, the American Heart Association and 24 collaborating organizations launched the PAD National Action Plan, a guide to assist in the prevention of PAD complications, treatment of cardiovascular risk and improvement of quality of life for those living with the disease.

“PAD is a lifelong medical condition, but people with PAD can lead active and long lives,” said American Heart Association volunteer expert and PAD National Action Plan writing group member Joshua Beckman, M.D., director of Vascular Medicine Section and professor of medicine Vanderbilt University in Nashville, Tennessee. “If you notice walking is becoming more difficult, keeping up with others is hard, or you have pain when you walk, talk with a doctor and describe when it happens and how it feels.”