Science

The pollution of the planet by microplastics is significantly cutting food supplies by damaging the ability of plants to photosynthesise, according to a new assessment.

The analysis estimates that between 4% and 14% of the world’s staple crops of wheat, rice and maize is being lost due to the pervasive particles. It could get even worse, the scientists said, as more microplastics pour into the environment.

About 700 million people were affected by hunger in 2022. The researchers estimated that microplastic pollution could increase the number at risk of starvation by another 400 million in the next two decades, calling that an “alarming scenario” for global food security.

Other scientists called the research useful and timely but cautioned that this first attempt to quantify the impact of microplastics on food production would need to be confirmed and refined by further data-gathering and research.

The annual crop losses caused by microplastics could be of a similar scale to those caused by the climate crisis in recent decades, the researchers behind the new research said. The world is already facing a challenge to produce sufficient food sustainably, with the global population expected to rise to 10 billion by around 2058.

Microplastics are broken down from the vast quantities of waste dumped into the environment. They hinder plants from harnessing sunlight to grow in multiple ways, from damaging soils to carrying toxic chemicals. The particles have infiltrated the entire planet, from the summit of Mount Everest to the deepest oceans.

“Humanity has been striving to increase food production to feed an ever-growing population [but] these ongoing efforts are now being jeopardised by plastic pollution,” said the researchers, led by Prof Huan Zhong, at Nanjing University in China. “The findings underscore the urgency [of cutting pollution] to safeguard global food supplies in the face of the growing plastic crisis.”

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The new study, published in the journal Proceedings of the National Academy of Sciences, combined more than 3,000 observations of the impact of microplastics on plants, taken from 157 studies.

Previous research has indicated that microplastics can damage plants in multiple ways. The polluting particles can block sunlight reaching leaves and damage the soils on which the plants depend. When taken up by plants, microplastics can block nutrient and water channels, induce unstable molecules that harm cells and release toxic chemicals, which can reduce the level of the photosynthetic pigment chlorophyll.

The researchers estimated that microplastics reduced the photosynthesis of terrestrial plants by about 12% and by about 7% in marine algae, which are at the base of the ocean food web. They then extrapolated this data to calculate the reduction in the growth of wheat, rice and maize and in the production of fish and seafood.

Asia was hardest hit by estimated crop losses, with reductions in all three of between 54m and 177m tonnes a year, about half the global losses. Wheat in Europe was also hit hard as was maize in the United States. Other regions, such as South America and Africa, grow less of these crops but have much less data on microplastic contamination.

In the oceans, where microplastics can coat algae, the loss of fish and seafood was estimated at between 1m and 24m tonnes a year, about 7% of the total and enough protein to feed tens of millions of people.

Childhood maltreatment exposure (CME) increases the risk of adverse long-term health consequences for the exposed individual. Animal studies suggest that CME may also influence the health and behaviour in the next generation offspring through CME-driven epigenetic changes in the germ line. Here we investigated the associated between early life stress on the epigenome of sperm in humans with history of CME. We measured paternal CME using the Trauma and Distress Scale (TADS) questionnaire and mapped sperm-borne sncRNAs expression by small RNA sequencing (small RNA-seq) and DNA methylation (DNAme) in spermatozoa by reduced-representation bisulfite sequencing (RRBS-seq) in males from the FinnBrain Birth Cohort Study. The study design was a (nested) case-control study, high-TADS (TADS ≥ 39, n = 25 for DNAme and n = 14 for small RNA-seq) and low-TADS (TADS ≤ 10, n = 30 for DNAme and n = 16 for small RNA-seq). We identified 3 genomic regions with differential methylation between low and high-TADS and 68 tRNA-derived small RNAs (tsRNAs) and miRNAs with different levels in males with high CME (False discovery rate, FDR corrected p < 0.05). Of potential interest, we identified differential expression of miRNA hsa-mir-34c-5p and differential methylation levels near the CRTC1 and GBX2 genes, which are documented to control brain development. Our results provide further evidence that early life stress influences the paternal germline epigenome and supports a possible effect in modulating the development of the central nervous system of the next generation.

Abstract Objective: To investigate whether the proportion of running-related knee injuries differed in normal-weight, overweight, and obese runners.

Design: Comparative study.

Methods: Data from 4 independent prospective studies were merged (2612 participants). The proportion of running-related knee injuries out of the total number of running-related injuries was calculated for normal-weight, overweight, and obese runners, respectively. The measure of association was absolute difference in proportion of running-related knee injuries with normal-weight runners as the reference group.

Results: A total of 571 runners sustained a running-related injury (181 running-related knee injuries and 390 running-related injuries in other anatomical locations). The proportion of running-related knee injuries was 13% lower (95% confidence interval: -22%, -5%; P = .001) among overweight runners compared with normal-weight runners. Similarly, the proportion of running-related knee injuries was 12% lower (95% confidence interval: -23%, -1%; P = .042) among obese runners compared with normal-weight runners.

Conclusion: Overweight and obese runners had a lower proportion of running-related knee injuries than normal-weight runners. J Orthop Sports Phys Ther 2020;50(7):397-401. doi:10.2519/jospt.2020.9233.

A major milestone in quantum computing has been achieved after researchers at the University of Oxford built a scalable quantum supercomputer capable of quantum teleportation.

The breakthrough centres on the so-called scalability problem of quantum computing, with the researchers claiming it will allow the next-generation technology to be realised on an industry-disrupting level.

The field of quantum computing has been around for decades, but only in recent years have significant advances been made towards realising them on a practical scale.

Utilising the properties of quantum physics, these next-generation machines replace traditional bits – the ‘ones’ and ‘zeros’ used to store and transfer digital information – with quantum bits (qubits), which can act as a one and a zero at the same time through a phenomenon known as superposition.

This give quantum computers the potential to be orders of magnitude more powerful than today’s state-of-the-art supercomputers that use conventional computing technology.

It is not the first time that scientists have achieved quantum teleportation, with teams previously transferring data from one location to another without moving qubits. However it is the first demonstration of quantum teleportation of logical gates – the minimum components of an algorithm – across a network link.

The researchers claim the quantum teleportation technique could form the foundation for a future ‘quantum internet’, which would offer an ultra-secure network for communications, computation and sensing.

“Previous demonstrations of quantum teleportation have focused on transferring quantum states between physically separated systems,” said Dougal Main, from the Department of Physics at the University of Oxford, who led the study.

“In our study, we use quantum teleportation to create interactions between these distant systems. By carefully tailoring these interactions, we can perform logical quantum gates – the fundamental operations of quantum computing – between qubits housed in separate quantum computers.

A gender specialist at the University of Genoa, in Italy, a psychologist at the University of Missouri, in the U.S., and a behavioralist at the University of Roehampton, in the U.K, have found that men are growing taller and heavier at twice the rate of women. In their study published in Biology Letters, the researchers analyzed a century's worth of data in the World Health Organization's database and found evidence of a growing sexual dimorphism in humans.

Prior research has shown that sexual size dimorphism exists in many species—in many, males are larger, due to competition for mates, or female preferences. In others, females are larger, generally for reproductive reasons. In humans, males are on average taller, more muscular and heavier than females. Prior research has shown the size difference has likely been due to males competing for females, with larger men tending to win such battles in times past.

In the modern age, such battles appear to be less of a factor, though males are still growing large. Some scientists have suggested this is because women prefer to mate with larger men. For this new study, the researchers looked at sexual size dimorphism in humans over the past century.

The researchers accessed the WHO database of information on millions of people going back to 1900. They analyzed data for approximately 135,000 people from 62 countries around the world and found that both men and women have been growing taller and heavier due to improvements in diet and health care. They were also able to compare height and weight ratios between males and females. They found that males have been growing taller and heavier at twice the rate of females.

The researchers note that such a rapid increase in size and weight by males has some drawbacks, mostly due to health issues. Taller men tend to be more prone to developing cancer, for example. They must also eat more to maintain their stature, which can lead to cardiovascular problems.