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The Independent
29-05-2025
- Health
- The Independent
Your cat may not show it – but it definitely knows your scent
Cats can tell their owners apart from strangers from the scent of their human companions, a new study reveals. Researchers from the Tokyo University of Agriculture say cats tend to spend a longer time sniffing the odour of a stranger than that of their owner, suggesting they can recognise familiar humans quickly based on smell. Previous studies have shown that cats use their sense of smell to identify other felines and communicate with each other. Whether they can also use scent to distinguish between humans has been unclear, however. The latest study, published on Wednesday in the journal PLoS, sought to find out if cats could tell familiar and unfamiliar humans apart based on smell alone. Researchers tested 30 domestic cats by presenting them with plastic tubes containing swabs rubbed under the armpit, behind the ear, and between the toes of either their owner or a human they had never met. They asked the cat owners to complete an online questionnaire to assess their pet's personality and their relationship. They observed that the study cats spent significantly longer sniffing an unknown odour than that of their owner or an empty tube. The felines tended to sniff unknown odours with their right nostril initially before switching to the left nostril as they became more familiar with the smell. Researchers found that male cats with seemingly neurotic personalities tended to sniff each tube repetitively. To the contrary, males with more agreeable personalities sniffed the tubes more calmly. No such effect of personality was seen on the behaviour of female cats during the experiment, according to the study. The findings suggest domestic cats can distinguish between familiar and unfamiliar humans based on their odour. It is still unclear, however, whether they identify specific humans based on smell alone. The research also reveals that cats have a right nostril preference for investigating new smells, indicating they may favour different hemispheres of their brain for different tasks. This phenomenon has previously been seen in other animals such as dogs, fish and birds. 'We suggest that cats use their olfaction for the recognition of humans. Also, we record characteristic rubbing behaviour occurring after sniffing, indicating that sniffing may be an exploratory behaviour preceding the rubbing of odour in cats,' the study notes. 'This relationship warrants further investigation along with the theory of whether cats are able to recognize a specific person from olfactory cues.'
BBC News
28-05-2025
- General
- BBC News
Cats distinguish their owner's scent from stranger's, study finds
Domestic cats can tell the difference between the smell of their owner and that of a stranger, a new study study by Tokyo University of Agriculture found cats spent significantly longer sniffing tubes containing the odours of unknown people compared to tubes containing their owner's suggests cats can discriminate between familiar and unfamiliar humans based on their odour, the researchers say, but that it is unclear whether they can identify specific are known to use their strong sense of smell to identify and communicate with other cats, but researchers had not yet studied whether they can also use it to distinguish between people. Previous studies of human recognition by cats have shown they are able to distinguish between voices, interpret someone's gaze to find food, and change their behaviour according to a person's emotional state that is recognised via their the study published on Wednesday, researchers presented 30 cats with plastic tubes containing either a swab containing the odour of their owner, a swab containing the odour of a person of the same sex as their owner who they had never met, or a clean swabs containing odours had been rubbed under the armpit, behind the ear, and between the toes of the owner or spent significantly more time sniffing the odours of unknown people compared to those of their owner or the empty tube, suggesting they can discriminate between the smells of familiar and unfamiliar people, the researchers idea of sniffing an unknown stimulus for longer has been shown before in cats - weaned kittens sniff unknown female cats for longer compared to their the researchers cautioned that it cannot be concluded the cats can identify specific people such as their owner."The odour stimuli used in this study were only those of known and unknown persons," said one of the study's authors, Hidehiko Uchiyama."Behavioural experiments in which cats are presented with multiple known-person odour stimuli would be needed, and we would need to find specific behavioural patterns in cats that appear only in response to the owner's odour." Serenella d'Ingeo, a researcher at the University of Bari who was not involved in this study but who has studied cat responses to human odours, also said the results demonstrated cats react differently to familiar and unfamiliar smells, but that conclusions couldn't be drawn over their motivations."We don't know how the animal felt during the sniffing... We don't know for instance whether the animal was relaxed or tense," she d'Ingeo added that the presentation of samples to cats by their own owners, who naturally added their own odour to the environment, could have increased the cats' interest in the unfamiliar ones."In that situation, owners present not only their visual presence but also their odour," she said."So of course if they present other odours that are different from their personal one, in a way they engage more the cat."The study's authors concluded that "cats use their olfaction [smell] for the recognition of humans".They also noted cats rubbed their faces against the tubes after sniffing - which cats do to mark their scent on something - indicating that sniffing may be an exploratory behaviour that precedes odour researchers cautioned that this relationship needs further investigation, along with the theory of whether cats can recognise a specific person from their smell.
Japan Times
25-05-2025
- Health
- Japan Times
Are microplastics hurting our fertility?
In February, Italian researchers announced what they claimed to be a world-first discovery: microplastic particles were found in the ovarian follicular fluid of women undergoing infertility treatment. The study adds to a growing body of research from around the world showing that tiny plastic particles have made their way into nearly every part of our body, from hair, saliva and blood to breast milk, the liver, kidneys and even the placenta. The research, published in the Ecotoxicology and Environmental Safety journal , warned of an 'emerging threat to female fertility' and called for 'further investigations to explore the possible damages that these microparticles can cause in terms of human reproduction and female fertility.' Japan, whose population is rapidly graying and dwindling, is no stranger to infertility. In 2021, 1 in 4.4 couples in the country said they had been tested or treated for conception problems, up from 1 in 8 in 2002. Could there be a worrisome connection? Experts say that more rigorous research is needed before saying that microplastics are linked to the infertility crisis. Still, scientists broadly agree that it's time for government regulators and citizens alike to rethink the approach toward plastic in order to protect our health. Hideshige Takada is one scientist who has been sounding the alarm. A professor emeritus at the Tokyo University of Agriculture and Technology and a pioneer in microplastics pollution research, he's particularly concerned about the effects of chemicals added to plastics. 'Compared with 10 years ago, we know much more about the harmful effects of microplastics,' he says. 'There's been growing evidence that many of the chemicals added to plastics to maintain or improve their functions ... are impacting human health.' Plastic pollution Plastic is part of the fabric of everyday life, from bags to bottles to synthetic clothing. And despite efforts by some countries, we keep producing more. In 2023, global production stood at 414 million tons, up from 311 million tons in 2014 and 225 million tons in 2004, according to the manufacturers group Plastics Europe. Plastic waste now litters the Earth, with much of it ending up in the oceans in the form of tiny fragments, or microplastics. Microplastics absorb toxic chemicals, get ingested by marine animals and climb back through the food chain. Hideshige Takada, a professor emeritus at the Tokyo University of Agriculture and Technology, is particularly concerned about the effects of chemicals added to plastics. | Tomoko Otake Microplastics are defined as plastic particles less than 5 millimeters in diameter, while nanoplastics are even smaller particles of less than 1 micrometer. They are produced from plastics that we use in daily life, either through litter or through products that fall through the recycling system, such as plastic waste that blows out of trash bins and winds up in rivers or oceans. When exposed to ultraviolet rays in strong sunlight, plastics decay and break into small pieces. These tiny particles are more easily carried offshore and accumulate in oceans. Synthetic clothes also shed microfibers, which are flushed from washing machines into wastewater, and into streams, rivers and oceans. Today, microplastics are everywhere in the environment, and as a result, we eat, drink and breathe them regularly. Endocrine-disrupting chemicals While there is some research saying microplastics themselves damage our body physically by causing inflammation, Takada says it is really the chemicals that do the most harm. Plastics contain a host of additives to keep them from degrading, such as antioxidants and UV absorbers. Also, they contain chemicals to add flexibility and prevent them from catching fire. Many of these chemicals have structures similar to female hormones, and they bind to hormone receptors in the cells when they enter the body, sending the wrong signals. They are known to act as endocrine disruptors, or 'environmental hormones.' 'Female hormones regulate sexual functions, reproduction and brain development, and that's why these chemicals are believed to cause problems in such functions,' Takada says. New research out of Italy is warning of an 'emerging threat to female fertility' after microplastics were discovered in the ovarian follicular fluid of women undergoing infertility treatment. | Getty Images 'We now know how these additives cause reproductive abnormalities, and we have over 1,000 studies saying additives have been found in the body. All things considered, I feel there's no room to doubt that plastic additives or monomers (the smallest unit of plastics) produced as a result of plastic breakdown affect human health.' Phthalates and bisphenol A are among the chemicals commonly used in plastics and are known to disrupt hormone functions. PFAS, also known as 'forever chemicals' because of their extreme persistence in the environment, are another group of substances that are commonly found in plastic products and are linked to a wide range of health issues, including cancer. Currently, the health ministry regulates some of the phthalates in children's toys and food containers and packaging, and sets maximum amounts for bisphenol A that can be transferred into food. Such regulations are effective in keeping the 'direct' exposure to harmful chemicals at bay, but not enough to prevent the 'indirect' exposure, through the fish we consume, the air we breathe or the water we drink, Takada argues. And regulations on specific chemicals fall short, he says. He cites a 2023 United Nations Environment Program report on chemicals in plastics, which states that over 3,200 chemicals detected in plastics have 'one or more hazardous properties of concern,' including ones that can 'mimic, block or alter the actions of hormones, reduce fertility, damage the nervous system, and/or cause cancer.' At present, only 130 of the 3,200 chemicals are regulated by international or regional treaties, according to Takada. Takada acknowledges issues raised regarding the quality of research. For example, the equipment researchers use to collect samples is rife with risks of plastic contamination. Also, there are chemicals in the human body that are very similar to plastics. Researchers may confuse the two, which could lead to the detection of unreasonably high levels of microplastics in the body, he says. In March, scientists at Irish and British institutions pointed to issues surrounding microplastics research in a commentary published by Nature , calling for 'more rigorous standards, transparency and collaboration' among researchers, policymakers and industrial stakeholders. They questioned many of the studies published so far, saying they rely on small sample sizes of typically 20 to 50 individuals. (The February ovarian study found microplastics in 14 of the 18 women checked.) 'Modern laboratories are themselves hotspots of nanoplastic and microplastic pollution, and the approaches that are being used to detect plastics make it hard to rule out the possibility of contamination, or prove definitively that plastics are in a sample,' they wrote. Male infertility The decline of semen quality, including a decrease in sperm counts and their swimming ability, has long been documented, with some researchers calling for more investigations into its link with Japan's falling birthrate . Soichiro Ogawa, associate professor of urology at the Fukushima Medical University's School of Medicine, sees many male patients with fertility issues. Based on the available evidence, however, the effects of microplastics or particular chemicals on male infertility remain unknown, he says. 'We can't draw conclusions from just one or two studies,' he says. 'There are so many studies out there, and even peer-reviewed ones are of mixed quality.' In addition to microplastics and toxic chemicals, many other environmental factors have been studied for their potential links to male infertility, ranging from heat, radiation, electromagnetic waves, pesticides and air pollution. Of all these, smoking poses the biggest risk, Ogawa says, noting that he recommends patients stop smoking to protect their health as well as their family's. A polluted beach on the banks of Guanabara Bay in Rio de Janeiro in 2022. Tiny plastic particles have made their way into nearly every part of our body, from hair, saliva and blood to breast milk, the liver, kidneys and even the placenta. | Reuters Takada argues there are limits to the evidence-based approach toward individual chemical substances. Modern plastic pollution is very different from 20th-century chemical pollution like the mercury poisoning that caused Minamata disease, where concentrations of specific chemicals were very high and it was relatively easy to identify the cause of the problem, he says. 'In the 21st century, we are dealing with numerous chemical substances or multiple factors that, on their own, may not have a health effect, but when combined, can cause harm,' Takada says. 'We're now in an era where it's increasingly difficult to pinpoint a single substance or phenomenon as the cause of a problem.' As such, reducing production and consumption of plastics as a whole, instead of regulating individual substances, is most effective to minimize exposure and risks of chemicals to humans, he argues. Policy changes Late last year, the 5th session of the U.N. Intergovernmental Negotiating Committee on plastic pollution (INC-5) was held in Busan, South Korea. But at the session, which was meant to be the last one, negotiators failed to reach a legally binding treaty to curb plastic pollution. The countries are meeting again in Geneva, Switzerland, in August. When it comes to policy changes, Japan may be able to learn from Europe, where the 'nudge' theory is used effectively, says Keita Nakayama, an environmental law expert and lecturer at Waseda University. The 'nudge,' a concept from behavioral economics, is called the fourth policy approach, after laws, taxes and subsidies. It is a tool to encourage people and businesses to make better decisions without coercing them. Used plastic bottles at a waste collection point in Tokyo. While 87% of Japan's plastic waste was recycled as of 2022, more than two-thirds of that was done through thermal recycling, which emits carbon dioxide and contributes to global warming. | Reuters Nakayama cites the case of the European strategy for plastics released by the EU in 2018, which included calling on companies and business groups to make voluntary pledges to use or produce more recycled plastics. He says it worked as a nudge even though the strategy was not legally binding on its own. The same day the strategy was announced, McDonald's said it would switch all of its packaging to renewable, recycled or certified sources in all restaurants worldwide by the end of 2025. Iceland Foods, a Wales-based supermarket chain famous for its frozen meals, also announced on the same day that it will eliminate plastic packaging from all of its brand products by 2023. Behind such corporate moves were advance coordination with businesses by authorities, which worked as a 'nudge,' Nakayama says. Japan introduced a plastic strategy of its own in 2019 and enforced a law aimed at promoting the resource circulation for plastics in 2022, but it has been criticized by environmental groups as lacking teeth and being too reliant on recycling instead of reducing the use of plastics. The introduction of a nationwide plastic bag fee for shoppers in July 2020 did work to reduce plastic waste, halving the volume of plastic bags in circulation to 100,000 tons in two years, according to the Environment Ministry. Now, well over 80% of people turn down plastic bags at retail stores, according to the latest statistics from the Japan Chain Stores Association, up from about 55% in 2019. But plastic shopping bags make up only a fraction of the country's total plastic waste. Plastic packages and containers — be it cutlery, PET bottles or bento boxes — are still everywhere, accounting for nearly half of the nation's plastic waste. Japan has been reluctant to regulate plastic production so far, refusing to join a proposal supported by about 100 countries to set a production reduction target during the INC-5 negotiations. In addition, while 87% of Japan's plastic waste was recycled as of 2022, more than two-thirds of that was done through thermal recycling, which emits carbon dioxide and contributes to global warming. So what should individuals do to reduce health risks? Takada says separating plastic from our food is key. Plastics degrade with heat, so avoiding reheating ready-made food in plastic containers and switching to glass instead of plastic for food storage is a good starting point, he says. PET bottles could also contain harmful chemicals in their caps, he adds. 'It's impossible to eliminate all sources of chemicals associated with plastics, but it would be helpful to reduce their use wherever possible,' he says. 'They don't stay long in the body, so reducing your daily exposure lowers your long-term risks.'
Tokyo Reported
10-05-2025
- Tokyo Reported
Suspect in stabbing near Tokyo University wanted to send message to 'education-conscious parents'
TOKYO (TR) – A 43-year-old man in custody over the alleged stabbing of university student on a Tokyo Metro subway line in Bunkyo Ward on Wednesday has told police that he committed the crime to send a message to his 'education-conscious parents,' reports the Yomiuri Shimbun (May 9). At just before 7:00 p.m. on Wednesday, Yoshitaka Toda, of no known occupation, allegedly used a kitchen knife to slash the head of a third-year Tokyo University student, 20, on a Namboku Line train stopped at Todai-mae Station. Three commuters apprehended Toda at the scene. One of them, a Nepalese man, suffered a cut index finger on his right hand. Police arriving at the station arrested Toda on suspicion of attempted murder. They also retrieved a butcher knife from the subway pkatform. Neither the student nor the Nepalese man suffered serious injuries, police said. Yoshitaka Toda (X) 'Crimes will occur' Police believe that he chose the station since it is named after Tokyo University and attacked passengers indiscriminately. According to a senior official with the Tokyo Metropolitan Police, Toda had remained silent during questioning after his arrest. But he started explaining his motive on Thursday. 'I wanted to show my education-conscious parents who were aiming for [me to go to] Tokyo University that if they go too far, crimes will occur,' he told police, according to an investigative source. Police found a butcher knife on the subway platform after the stabbing on Wednesday night (X) 'I didn't care if he died' Toda, who lives in the village of Ikusaka, Nagano Prefecture, said that he stopped going to school in junior high school because of his strict parents. He confessed, 'The station is named after Tokyo University, so I thought it would be easy to associate it with educational abuse.' When asked why he attacked the student, he said, 'I targeted him because he happened to be nearby. I didn't care if he died.' On Friday, police sent Toda to the Tokyo District Public Prosecutors Office on suspicion of attempted murder and violation of the Swords and Firearms Control Law.
Euronews
24-04-2025
- Health
- Euronews
Smartphones aren't just stress-inducing. They could also help boost mental health, researchers say
ADVERTISEMENT A smartphone app could equip people with the skills to overcome low-level depression, according to new research that suggests the devices often blamed for poor mental health could also be part of the solution. Globally, an estimated 11 per cent of people have 'subthreshold depression,' which is mild depression that doesn't quite meet the criteria for major depressive disorder but can still have a serious impact on a person's well-being. Cognitive behavioural therapy (CBT), which focuses on helping people change and cope with their unhealthy thoughts and behaviours, is considered the gold standard for mental health treatment. Related Paging doctor bot: Why AI therapy is providing hope in the midst of a mental health crisis In many cases, it's equally or more effective than medication. But with a shortage of psychiatrists around the world, demand for mental healthcare often outstrips supply. CBT is 'highly effective' but scale is a challenge The new study, which was published in the journal Nature Medicine , tested whether a CBT-focused smartphone app could be enough to help fill that gap. The app focused on building five key CBT skills: getting people to do mood-boosting activities, rerouting the negative thoughts behind their feelings of depression, improving their problem-solving abilities, helping them articulate themselves without hurting other people's feelings, and practicing techniques to ensure they get enough sleep. 'CBT is highly effective, but delivering it at scale has always been a challenge,' Toshiaki Furukawa, the study's lead author and a professor at Tokyo University, said in a statement. Related Popular ADHD TikTok videos often do not accurately reflect symptoms, experts say 'Our goal was to make these skills available to anyone, anywhere'. For the experiment, nearly 4,000 Japanese adults with subthreshold depression were randomly assigned to either use the app – or not use it. Those with the app had access to different combinations of the CBT skills. They tended to stop using it after six to 10 weeks, once they had finished their lessons. Those who used the app had better mental health afterward, with lower levels of depression, anxiety, and insomnia. The findings held up for six months, when the study ended. Study's noteworthy results The results are notable because the evidence is mixed on whether CBT-focused apps can actually boost mental health. Related Therapy using a digital avatar could help patients suffering from psychosis, study says In one analysis that pooled 24 studies, researchers concluded that short, phone-based interventions can help reduce symptoms of mental disorders. But in another experiment funded by the European Union , automated self-help interventions did not improve people's well-being – possibly because they focused on a low-risk group of university students with no history of major depression. In the new study, some of the CBT skills were more effective for certain conditions than others. ADVERTISEMENT For example, the mood-boosting and sleep-training elements were particularly helpful at curbing anxiety, improving sleep, and promoting positive mental well-being overall. Related Taking ChatGPT to 'therapy' for anxiety helps with bias, researchers say Meanwhile, the tools to correct people's negative thoughts didn't appear very effective. The researchers are now preparing for a longer experiment that targets people's specific mental health problems. 'We can use this knowledge to personalise and optimise which skills to administer for each individual to match their needs and characteristics,' Furukawa said. ADVERTISEMENT 'This opens the door to optimised, long-term support'.
