Drawing the line: Virtual versus physical fences

Researchers at Göttingen University show value of invisible boundaries in field trials with cattle

University of Göttingen

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Cattle are grazing within a pasture area defined by the "Nofence" virtual fencing system on Göttingen University's farming area to carry out research in Relliehausen (2021).

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Credit: Göttingen University / Natascha A. Grinnell

Virtual fences could make managing grazing livestock on farms more flexible and more efficient whilst improving animal welfare. A new study by the University of Göttingen shows that virtual fences trigger similar behaviour in cattle, in terms of how they move around in the field, to conventional electric fences. This finding clearly puts the concerns, which are commonly expressed about animal welfare, into perspective. The results were published in the journal Animal.

 

In previous research on this theme, cattle wore collars which emitted acoustic signals – and, where necessary, electrical pulses – when they approached the boundary. During the learning process, the animals associated the warning tone with the unpleasant stimulus and subsequently, mostly respected the virtually defined boundary simply as a response to the noise. As previous analyses of the experiment had not revealed any significant behavioural differences between animals in virtual and conventionally fenced enclosures, the researchers decided to take a closer look in their current study. In order to map the distance to the fence – and identify any effect on the cattle’s behaviour that might only occur in the vicinity of the virtual boundary – they used GPS to assign the movement data of the 31 cows to two different zones (peripheral zone and centre of the pasture) and compared them.

 

The key finding was that it was not the type of fence that made the difference, but the boundary itself – regardless of whether it was visible or not. Regardless of the system used, the animals were less likely to be found at the edges of the field, moved more slowly there, and tended to use the centre of the pasture. Virtual fences also led to a more even distribution of the animals across the area.

 

“Our findings show that it is not the type of fence that is the deciding factor, but rather the animals’ perception of the boundary of the pasture,” says lead author Dr Natascha Grinnell at Göttingen University’s Institute of Grassland Science. “Virtual fences are respected by cattle just as reliably as conventional electric fences and are not fundamentally more problematic from an animal welfare perspective. This opens up new opportunities for farmers to manage grazing in a modern and flexible way.”

 

Researchers from the University of Göttingen will also be presenting their findings at the ‘Virtual Fencing’ field day on Monday 6 July in Alt Madlitz, Brandenburg. Further information about the event can be found here (in German): https://shop.gutundboesel.org/products/grosser-feldtag-mit-hoftour-virtual-fencing-6-juli-2026.

Original publication: Grinnell, N.A. et al. “Drawing the line: Comparing zone-specific spatial behaviour of heifers on pasture with virtual and physical fences”. Animal (2026). DOI: 10.1016/j.animal.2026.101820.

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Journal

animal

DOI

10.1016/j.animal.2026.101820 

Method of Research

Experimental study

Subject of Research

Not applicable

Article Title

Drawing the line: Comparing zone-specific spatial behaviour of heifers on pasture with virtual and physical fences

 

Cattle are resting in the field at Göttingen University’s farming area to carry out research in Relliehausen during a trial of grazing using the "Nofence" virtual fencing system (2021).

 

Dr Natascha Grinnell and Dr Dina Hamidi in front of a cow wearing a "Nofence" collar. The photograph was taken in 2021 at Göttingen University’s farming area to carry out research in Relliehausen during a trial of grazing using the "Nofence" virtual fencing system.

Credit

Göttingen University / Natascha A. Grinnell

 

Obesity rates in the US climbed to about 40% of adults and 20% of youth in 2023

More than 20 years of data show a 37% increase in obesity, 23% in abdominal obesity, and over two-fold increase in severe obesity among both adults and youth, according to authors of a new study published in the journal Circulation

American Heart Association

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Research Highlights:

• Researchers analyzed U.S. health information from 1999 to 2023 and found that the prevalence of obesity increased from 30% to 41%, respectively.
• Severe obesity among U.S. adults rose from 5% to 10%, and abdominal obesity (the accumulation of fatty tissue in the abdominal area) increased from 48% to 61%, respectively, during the 24-year study period.
• Researchers recommended ongoing monitoring of body mass index (BMI) and waist circumference to help guide individual and population-wide prevention efforts targeting obesity as a major modifiable risk factor.

Embargoed until 4 a.m. CT/5 a.m. ET on Tuesday, July 7, 2026

DALLAS, July 7, 2026 — Obesity rates among U.S. adults and children rose sharply in recent years and by 2023, 40% of adults and 20% of youth met the criteria for obesity, according to new, independent research published today in the American Heart Association’s flagship journal Circulation.

“Obesity is a leading public health concern, linked to higher risks for cardiovascular disease and premature death,” said study author Anum Minhas, M.D., M.H.S., an assistant professor of medicine in cardiology at the Johns Hopkins School of Medicine in Baltimore. “Examining national trends in obesity can help determine which segments of the population may benefit the most from screening, how resources should be allocated for preventive efforts and the potential impact of implementing public health initiatives to reduce the burden of obesity.” Minhas said the research is believed to be the most contemporary evaluation of obesity trends among U.S. adults and youth.

In the study, researchers defined obesity as a body mass index (BMI) of 30 kg/m² or higher (except for Asian populations where distinct race-specific cutoffs were used). Obesity can increase the risks for health conditions, including Type 2 diabetes, high blood pressure, heart disease, stroke and chronic kidney disease. Severe obesity, which study researchers defined as a BMI greater than or equal to 40 kg/m², carries the highest risks for cardiovascular disease and death.

The first ever guideline from the American Heart Association on the Prevention, Detection, Evaluation and Management of Cardiovascular-Kidney-Metabolic disease, published in June 2026, states that obesity is the first stage of cardiovascular-kidney-metabolic syndrome. The guideline emphasizes obesity management in the form of diet and lifestyle modifications as essential for a longer, healthier life.

In this study, researchers examined how rates of various levels of obesity changed over more than 20 years, according to data from the National Health and Nutrition Examination Survey (NHANES). Rates and prevalence of obesity, severe obesity and abdominal obesity were analyzed, and potential trends by age, sex, race and ethnic groups were measured.

What are the key findings of the analysis?

• Among the nearly 8,700 people in the U.S. surveyed between 1999 and 2023, including youth, defined as less than 20 years old, and adults, 20 years old and over.
• Among adults, researchers found notable increases in the prevalence of obesity (30% to 41%, respectively), severe obesity (5% to 10%, respectively) and abdominal obesity (48% to 61%, respectively) in 1999 vs. 2023.
• Among youth, researchers noted about a 30% increase for overall obesity, a 50% increase for severe obesity and a three-fold increase in abdominal obesity when comparing 1999 vs. 2023.
• Disparities in obesity prevalence were also found in the analysis, with women being more likely to have severe obesity (13%) and abdominal obesity (70%) compared to men, who were less likely to have severe obesity (7%) and abdominal obesity (51%) as of the last time data was taken in 2023. The gap between women and men could be due to women having more hormonal differences and changes throughout their lives than men, researchers noted.
• Throughout the period studied, non-Hispanic Black people consistently had the highest prevalence of all obesity compared to all other demographic groups.

These findings have major implications for cardiovascular disease and mortality, according to Minhas. “We must increase the availability and use of individual and population-level initiatives to target the rising epidemic of obesity and support people with obesity,” she said. “This includes pursuing a better understanding of which patients could benefit most from weight loss medications or other treatments. There are several effective weight loss therapies, including GLP-1 receptor agonist medications, bariatric surgery and other treatment options, confirmed in recent studies to have a positive impact on metabolic risk factors (blood sugar, blood pressure and cholesterol levels) and cardiovascular health, approved by the FDA and recommended in evidence-based treatment guidelines.”

What are the study’s details, background, design and limitations?

• Between 1999 to 2023, a median of 8,687 individuals in the U.S. were surveyed through NHANES, including about 50% women. Approximately one-third of participants were youth younger than age 20 years, and two-thirds were adults ages 20 and older.
• NHANES is conducted continuously at several sites across the U.S., and the researchers analyzed participants’ health information and survey responses between 1999 and 2023, including demographic, clinical and biomarker data.
• Limitations of the analysis include that participants’ BMI measures were used to define obesity and classify different obesity levels. The study did not include body composition (fat mass versus lean mass) to classify participants’ obesity status or levels. In addition, NHANES response rates decreased over time, which increases the chance of nonresponse bias (those who didn’t respond may have had different outcomes or results from those who did continue to respond and participate in the survey, possibly skewing the results).

Co-authors, disclosures and funding sources are listed in the manuscript.

Studies published in the American Heart Association’s scientific journals are peer-reviewed. The statements and conclusions in each manuscript are solely those of the study authors and do not necessarily reflect the Association’s policy or position. The Association makes no representation or guarantee as to their accuracy or reliability. The Association receives more than 85% of its revenue from sources other than corporations. These sources include contributions from individuals, foundations and estates, as well as investment earnings and revenue from the sale of our educational materials. Corporations (including pharmaceutical, device manufacturers and other companies) also make donations to the Association. The Association has strict policies to prevent any donations from influencing its science content and policy positions. Overall financial information is available here.

Additional Resources:

• Multimedia is available on the right column of release link.
• After July 7, 2026, view the manuscript online.
• American Heart Association Guideline: First-ever guideline on cardiovascular-kidney-metabolic syndrome issued (June 2026)
• American Heart Association Scientific Statement: Role of Physical Activity in Obesity Treatment and Cardiometabolic Health (May 2026)
• American Heart Association Scientific Statement: Obesity and Cardiovascular Disease (May 2021)
• American Heart Association health information: Understanding Excess Weight and Supportive Solutions
• American Heart Association health initiative: Life’s Essential 8
• Follow American Heart Association/American Stroke Association news on X @HeartNews
• Follow news from the American Heart Association’s flagship journal Circulation on X  @CircAHA

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About the American Heart Association

The American Heart Association is a relentless force for a world of longer, healthier lives. Dedicated to ensuring equitable health in all communities, the organization has been a leading source of health information for more than one hundred years. Supported by more than 35 million volunteers globally, we fund groundbreaking research, advocate for the public’s health, and provide critical resources to save and improve lives affected by cardiovascular disease and stroke. By driving breakthroughs and implementing proven solutions in science, policy, and care, we work tirelessly to advance health and transform lives every day. Connect with us on heart.org, Facebook, X or by calling 1-800-AHA-USA1.

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Journal

Circulation

DOI

10.1161/CIRCULATIONAHA.126.080146 

Article Title

Obesity, Severe Obesity, and Abdominal Obesity in US Youth and Adults From 1999 to 2023

 

Parental Holocaust trauma linked to higher risk of schizophrenia in offspring, new study finds

The Hebrew University of Jerusalem

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Hagit Hochner

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Credit: Itai Belson

Can the trauma of a parent rewrite the mental health of a child born decades later? A new compelling study reveals that children born decades after the Holocaust to parents who were older than age five at the time of the initial Nazi persecutions faced elevated schizophrenia risk. This preconception echo underscores specific periods of vulnerability to trauma experienced in childhood and suggests that the shadows of atrocities can quietly reach across generations.

Children born decades after World War II to mothers who were older than age 5 at the time of the initiation of Nazi persecutions, face and over two-fold increase in the risk of schizophrenia, according to a study published in the American Journal of Psychiatry.

The research was led by Prof. Hagit Hochner and Dr. Iaroslav Youssim from the Braun School of Public Health and Community Medicine at the Hebrew University of Jerusalem and Prof. Dolores Malaspina from Mount Sinai School of Medicine, New York, and their colleagues. The research team investigated the long-term, intergenerational impacts of severe preconception trauma by evaluating whether the children of Holocaust survivors are at increased risk for severe psychiatric disorders.

Tracking Two Generations of Health Data

To understand this relationship, researchers utilized data from the Jerusalem Perinatal Study, which tracked births in West Jerusalem between 1964 and 1976. They linked these records to Israel's National Psychiatric Registry through December 2004 to monitor hospitalizations for schizophrenia and related disorders. The team analyzed two large data samples consisting of 14,759 children of tracked mothers and 18,085 children of tracked fathers.

Parents were classified as "exposed" if they were of Jewish ancestry, born in European countries under Nazi rule, and immigrated to Israel after anti-Jewish persecutions commenced in their home countries. The researchers further separated these parents into subgroups based on how old they were when the persecutions began: either five years old and younger, or older than five. Unexposed parents were of European descent not living under Nazi rule.

The Crucial Factor of Age and Timing

The findings revealed a stark difference based on the parent's age at the time of the trauma. Offspring of mothers who were older than age five when Nazi persecutions began demonstrated an over two-fold increase in the risk of schizophrenia. This risk remained highly pronounced and statistically robust even after the researchers adjusted for sociodemographic factors, birth weight, and the mother's own history of psychiatric hospitalization.

Conversely, no elevated risk of schizophrenia was detected in the offspring of parents who were five years old or younger when the persecutions started. The researchers suggested that very young children might have been better shielded from their immediate environment by primary caregivers, or that their developing cognitive faculties altered their perception of the danger around them.

Maternal vs. Paternal Inheritance Pathways

The study also illuminated notable differences between maternal and paternal trauma transmission. While the children of fathers who were older than five at the time of exposure initially showed an elevated risk of schizophrenia, this association diminished and became statistically non-significant once adjusted for sociodemographic variables.

The enduring strength of the maternal connection suggests that the intergenerational transmission of trauma may operate through distinct biological and environmental pathways. The researchers noted that maternal trauma might impact future generations via the intrauterine environment during pregnancy, greater maternal engagement in early childhood parenting, or epigenetic alterations in the germline that transmit stress information across generations.

While the study had limitations, such as an inability to capture subjective personal experiences of the Holocaust or tracking participants past 2005 when later-onset cases might appear, its population-based design provides substantial evidence of how historical atrocities leave an imprint on the mental health of subsequent generations. Professor Hochner and her team emphasized that ongoing research across different historical and geographical settings will remain vital to fully understand the deep-rooted legacies of trauma.

“Our work underscores that war does not only have devastating immediate consequences, but also places a profound intergenerational burden on the future,” said Prof. Hagit Hochner, joint senior author of the study. “As conflict and warfare continue to escalate and to displace and traumatize populations globally, understanding these preconception pathways is crucial for anticipating future public health burdens. It is in fact our professional duty to study these effects and to bring it to public awareness. Ending war and striving for peace is a Public Health imperative.”

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Journal

American Journal of Psychiatry

DOI

10.1176/appi.ajp.20241145 

Method of Research

Observational study

Subject of Research

People

Article Title

Schizophrenia in Offspring of Holocaust Survivors: Intergenerational Effects of Preconception Parental Trauma Within the Jerusalem Perinatal Study

 

Climate oscillations shape nature’s coral refuges in a warming ocean

New study reveals that natural cooling of coral reefs is not constant – but depends on major tropical climate patterns.

MARUM - Center for Marine Environmental Sciences, University of Bremen

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MARUM researchers Hana Camelia and Thomas Felis examining cores of tropical coral colonies. Photo: Patrick Pollmeier, University of Bremen

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Credit: Patrick Pollmeier, University of Bremen

The study focuses on a coral reef in the Andaman Sea in the northeastern Indian Ocean that regularly experiences cooling from subsurface ocean waters driven by internal waves and changes in thermocline depth – the boundary separating warm surface water from cooler deeper water. These oceanographic processes can temporarily relieve heat stress on corals, potentially reducing the impacts of marine heatwaves. However, the research shows that this natural protection is far from constant. Instead, it varies with large-scale climate oscillations that shape conditions across the tropical Indo-Pacific.

Coral skeletons reveal the ocean’s hidden history
To understand how this natural cooling has changed over time, the researchers combined long-term subsurface temperature measurements with geochemical analyses of coral skeletons. Corals act as natural environmental archives, recording changes in seawater conditions as they grow.

By analysing strontium-to-calcium (Sr/Ca) ratios preserved within the skeleton, the team reconstructed past subsurface temperatures. They complemented this with measurements of carbon isotopes, which reveal how corals adjusted their metabolism during periods of heat stress. Together, these records allowed the scientists to reconstruct both the history of cooling events and the biological responses of the corals themselves.

Climate patterns determine the strength of natural refuges
One of the study’s key findings is that the cooling experienced at this reef refuge is strongly controlled by two major modes of tropical climate variability: the El Niño–Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD). These climate phenomena influence regional wind patterns and the depth of the thermocline, ultimately determining how effectively cool subsurface water can reach shallow coral reefs.

The researchers found that the most pronounced cooling occurred during the exceptional 1997/1998 El Niño, which coincided with a strong positive Indian Ocean Dipole. During this period, the thermocline became unusually shallow, allowing internal waves to transport greater amounts of cool water onto the reef. Although this event triggered one of the most severe global coral bleaching episodes on record, the enhanced cooling substantially reduced thermal stress at the study site.

Corals change their strategy during heat stress
The chemical signatures preserved within the coral skeletons also reveal how corals cope with heat stress conditions. Under normal circumstances, reef-building corals rely primarily on microscopic algae living within their tissues for energy. During bleaching events, however, this partnership can break down.
The carbon isotope analyses suggest that, during many bleaching episodes, the corals compensated by increasing heterotrophy – that is, by capturing more food particles from the surrounding seawater. Interestingly, this shift was much less evident during the 1998 event, suggesting that the unusually strong natural cooling helped corals maintain their normal nutritional strategy despite widespread regional heat stress.

Why this matters for coral conservation
The findings highlight that coral refuges should not be viewed as permanently protected locations. Instead, their ability to buffer heat stress depends on the state of the climate system. As large-scale ocean-atmosphere circulation changes from year to year and decade to decade, so too does the effectiveness of these naturally cooled environments.
Understanding this dynamic relationship will help scientists better predict where corals are most likely to survive future marine heatwaves. It also provides valuable guidance for conservation planning, allowing managers to identify reef systems that are most likely to function as climate refuges under future warming.

A dynamic view of reef resilience
Rather than offering permanent shelter from climate change, naturally cooled reefs provide protection that waxes and wanes with tropical climate variability. By combining coral geochemistry with decades of oceanographic observations, this study demonstrates how processes operating across entire ocean basins can determine the fate of individual coral reefs.
As marine heatwaves become increasingly frequent, understanding when and where these natural refuges are most effective will be essential for protecting coral reef ecosystems in a warming world.

Research collaboration and support
This study was carried out within the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) Priority Programme “Tropical Climate Variability & Coral Reefs” (SPP 2299). Led by MARUM researchers Hana Camelia and Thomas Felis, the study was conducted in close collaboration with researchers from Thailand, bringing together expertise in coral geochemistry, coral reef ecology, oceanography, and climate science to better understand how coral reefs respond to a changing climate.

Further Information:
DFG Priority Programme “Tropical Climate Variability & Coral Reefs” (SPP 2299): https://www.spp2299.tropicalclimatecorals.de/
MARUM Coral Paleoclimatology: https://www.marum.de/en/Coral-Paleoclimatology.html

MARUM produces fundamental scientific knowledge about the role of the ocean and the ocean floor in the total Earth system. The dynamics of the ocean and the ocean floor significantly impact the entire Earth system through the interaction of geological, physical, biological and chemical processes. These influence both the climate and the global carbon cycle, and create unique biological systems. MARUM is committed to fundamental and unbiased research in the interests of society and the marine environment, and in accordance with the Sustainable Development Goals of the United Nations. It publishes its quality-assured scientific data and makes it publicly available. MARUM informs the public about new discoveries in the marine environment and provides practical knowledge through its dialogue with society. MARUM cooperates with commercial and industrial partners in accordance with its goal of protecting the marine environment.

 

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Journal

Scientific Reports

DOI

10.1038/s41598-026-52941-6 

Article Title

Tropical climate modes control strength and distribution of thermal stress mitigation in a coral reef refugia.