Thursday, August 22, 2024

 

MIT engineers’ new theory could improve the design and operation of wind farms



The first comprehensive model of rotor aerodynamics could improve the way turbine blades and wind farms are designed and how wind turbines are controlled.



Massachusetts Institute of Technology





The blades of propellers and wind turbines are designed based on aerodynamics principles that were first described mathematically more than a century ago. But engineers have long realized that these formulas don’t work in every situation. To compensate, they have added ad hoc “correction factors” based on empirical observations.

Now, for the first time, engineers at MIT have developed a comprehensive, physics-based model that accurately represents the airflow around rotors even under extreme conditions, such as when the blades are operating at high forces and speeds, or are angled in certain directions. The model could improve the way rotors themselves are designed, but also the way wind farms are laid out and operated. The new findings are described in the journal Nature Communications, in an open-access paper by MIT postdoc Jaime Liew, doctoral student Kirby Heck, and Michael Howland, the Esther and Harold E. Edgerton Assistant Professor of Civil and Environmental Engineering.

“We’ve developed a new theory for the aerodynamics of rotors,” Howland says. This theory can be used to determine the forces, flow velocities, and power of a rotor, whether that rotor is extracting energy from the airflow, as in a wind turbine, or applying energy to the flow, as in a ship or airplane propeller. “The theory works in both directions,” he says.

Because the new understanding is a fundamental mathematical model, some of its implications could potentially be applied right away. For example, operators of wind farms must constantly adjust a variety of parameters, including the orientation of each turbine as well as its rotation speed and the angle of its blades, in order to maximize power output while maintaining safety margins. The new model can provide a simple, speedy way of optimizing those factors in real time.

“This is what we’re so excited about, is that it has immediate and direct potential for impact across the value chain of wind power,” Howland says. 

Modeling the momentum

Known as momentum theory, the previous model of how rotors interact with their fluid environment — air, water, or otherwise — was initially developed late in the 19th century. With this theory, engineers can start with a given rotor design and configuration, and determine the maximum amount of power that can be derived from that rotor — or, conversely, if it’s a propeller, how much power is needed to generate a given amount of propulsive force.

Momentum theory equations “are the first thing you would read about in a wind energy textbook, and are the first thing that I talk about in my classes when I teach about wind power,” Howland says. From that theory, physicist Albert Betz calculated in 1920 the maximum amount of energy that could theoretically be extracted from wind. Known as the Betz limit, this amount is 59.3 percent of the kinetic energy of the incoming wind. 

But just a few years later, others found that the momentum theory broke down “in a pretty dramatic way” at higher forces that correspond to faster blade rotation speeds or different blade angles, Howland says. It fails to predict not only the amount, but even the direction of changes in thrust force at higher rotation speeds or different blade angles: Whereas the theory said the force should start going down above a certain rotation speed or blade angle, experiments show the opposite — that the force continues to increase. “So, it’s not just quantitatively wrong, it’s qualitatively wrong,” Howland says.

The theory also breaks down when there is any misalignment between the rotor and the airflow, which Howland says is “ubiquitous” on wind farms, where turbines are constantly adjusting to changes in wind directions. In fact, in an earlier paper in 2022, Howland and his team found that deliberately misaligning some turbines slightly relative to the incoming airflow within a wind farm significantly improves the overall power output of the wind farm by reducing wake disturbances to the downstream turbines.

In the past, when designing the profile of rotor blades, the layout of wind turbines in a farm, or the day-to-day operation of wind turbines, engineers have relied on ad hoc adjustments added to the original mathematical formulas, based on some wind tunnel tests and experience with operating wind farms, but with no theoretical underpinnings.

Instead, to arrive at the new model, the team analyzed the interaction of airflow and turbines using detailed computational modeling of the aerodynamics. They found that, for example, the original model had assumed that a drop in air pressure immediately behind the rotor would rapidly return to normal ambient pressure just a short way downstream. But it turns out, Howland says, that as the thrust force keeps increasing, “that assumption is increasingly inaccurate.”

And the inaccuracy occurs very close to the point of the Betz limit that theoretically predicts the maximum performance of a turbine — and therefore is just the desired operating regime for the turbines. “So, we have Betz’s prediction of where we should operate turbines, and within 10 percent of that operational set point that we think maximizes power, the theory completely deteriorates and doesn’t work,” Howland says.

Through their modeling, the researchers also found a way to compensate for the original formula’s reliance on a one-dimensional modeling that assumed the rotor was always precisely aligned with the airflow. To do so, they used fundamental equations that were developed to predict the lift of three-dimensional wings for aerospace applications. 

The researchers derived their new model, which they call a unified momentum model, based on theoretical analysis, and then validated it using computational fluid dynamics modeling. In follow up work not yet published, they are doing further validation using wind tunnel and field tests.

Fundamental understanding

One interesting outcome of the new formula is that it changes the calculation of the Betz limit, showing that it’s possible to extract a bit more power than the original formula predicted. Although it’s not a significant change — on the order of a few percent — “it’s interesting that now we have a new theory, and the Betz limit that’s been the rule of thumb for a hundred years is actually modified because of the new theory,” Howland says. “And that’s immediately useful.” The new model shows how to maximize power from turbines that are misaligned with the airflow, which the Betz limit cannot account for.

The aspects related to controlling both individual turbines and arrays of turbines can be implemented without requiring any modifications to existing hardware in place within wind farms. In fact, this has already happened, based on earlier work from Howland and his collaborators two years ago that dealt with the wake interactions between turbines in a wind farm, and was based on the existing, empirically based formulas.

“This breakthrough is a natural extension of our previous work on optimizing utility-scale wind farms,” he says, because in doing that analysis, they saw the shortcomings of the existing methods for analyzing the forces at work and predicting power produced by wind turbines. “Existing modeling using empiricism just wasn’t getting the job done,” he says. 

In a wind farm, individual turbines will sap some of the energy available to neighboring turbines, because of wake effects. Accurate wake modeling is important both for designing the layout of turbines in a wind farm, and also for the operation of that farm, determining moment to moment how to set the angles and speeds of each turbine in the array.

Until now, Howland says, even the operators of wind farms, the manufacturers, and the designers of the turbine blades had no way to predict how much the power output of a turbine would be affected by a given change such as its angle to the wind without using empirical corrections. “That’s because there was no theory for it. So, that’s what we worked on here. Our theory can directly tell you, without any empirical corrections, for the first time, how you should actually operate a wind turbine to maximize its power,” he says.

Because the fluid flow regimes are similar, the model also applies to propellers, whether for aircraft or ships, and also for hydrokinetic turbines such as tidal or river turbines. Although they didn’t focus on that aspect in this research, “it’s in the theoretical modeling naturally,” he says.

The new theory exists in the form of a set of mathematical formulas that a user could incorporate in their own software, or as an open-source software package that can be freely downloaded from GitHub. “It’s an engineering model developed for fast-running tools for rapid prototyping and control and optimization,” Howland says. “The goal of our modeling is to position the field of wind energy research to move more aggressively in the development of the wind capacity and reliability necessary to respond to climate change.”

The work was supported by the National Science Foundation and Siemens Gamesa Renewable Energy.

###

Written by David L. Chandler, MIT News

Breakthrough in cost-effective production of cultivated meat



The Hebrew University of Jerusalem
Prof. Koby Nahmias 

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Prof. Koby Nahmias working in his lab. 

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Credit: Nahmias Lab




A groundbreaking study demonstrates the first cost-effective method for producing cultivated meat. The study shows that continuous manufacturing addresses the key challenges of scalability and cost, potentially making cultivated meat accessible to everyday consumers and contributing to a more sustainable and ethical food system.

In an extraordinary stride for cellular agriculture, Professor Yaakov Nahmias, founder of Believer Meats, and a multidisciplinary team at the Hebrew University of Jerusalem and the cultivated meat industry unveiled a pioneering continuous manufacturing process for cultivated meat. This innovation tackles the industry's critical challenges of scalability and cost-effectiveness.

The study, "Continuous Manufacturing of Cultivated Meat: Empirical Economic Analysis," published in Nature Food, demonstrates the use of tangential flow filtration (TFF) for the continuous manufacturing of cultivated meat. The new bioreactor assembly permits biomass expansion to 130 billion cells per liter, achieving yields of 43% weight per volume. The process was carried out continuously over 20 days, enabling daily biomass harvests.  Additionally, the research introduces an animal component-free culture medium, priced at just $0.63 per liter, which supports the long-term, high-density culture of chicken cells. In other words, this continuous manufacturing method could significantly reduce the cost and complexity of cultivated meat production, potentially bringing it closer to everyday consumers.

"We were inspired by how Ford’s automated assembly line revolutionized the car industry 110 years ago,” stated Prof. Nahmias. "Our findings show that continuous manufacturing enables cultivated meat production at a fraction of current costs, without resorting to genetic modification or mega-factories. This technology brings us closer to making cultivated meat a viable and sustainable alternative to traditional animal farming."

Bruce Friedrich, President of The Good Food Institute, expressed his support, stating, “GFI applauds the spirit of openness that continues to characterize cultivated meat researchers like Dr. Koby Nahmias and his colleagues, who understand that showing the scientific potential of cultivated meat will benefit all scientists working in the field.”

This research represents a significant advance in the economic feasibility of cultivated meat, addressing previous concerns about high costs and low yields. Utilizing this empirical data, the team conducted a techno-economic analysis of a hypothetical 50,000-liter production facility. The analysis indicates that the cost of production of cultivated chicken could theoretically be reduced to $6.20 per pound, aligning with the price of organic chicken.

Dr. Elliot Swartz, Principal Scientist at Cultivated Meat, The Good Food Institute emphasized the significance of the study’s findings, stating “This important study provides numerous data points that demonstrate the economic feasibility of cultivated meat. The study confirms early theoretical calculations that serum-free media can be produced at costs well below $1/L without forfeiting productivity, which is a key factor for cultivated meat achieving cost-competitiveness.” Dr. Swartz added that “Empirical data is the bedrock for any cost model of scaled cultivated meat production, and this study is the first to provide real-world empirical evidence for key factors that influence the cost of production, such as media cost, metabolic efficiency, and achievable yields in a scalable bioprocess design.”

While the authors acknowledged that various other factors would affect the final market price of cultivated meat, this research underscores the potential of continuous manufacturing to significantly lower production costs, making cultivated meat more accessible to consumers and competitive with conventional meat products.

This study not only highlights the promise of cellular agriculture in meeting the global demand for animal products but also aligns with broader environmental and ethical objectives by reducing reliance on traditional livestock farming.

The research represents the first demonstration of cost-efficient manufacturing of cultivated meat and the first empirical economic analysis based on solid data. It is a collaborative effort involving engineers, biologists, and chemists at the Hebrew University of Jerusalem and ADM-funded Believer Meats, which is currently building the world's first large-scale industrial production facility for cultivated chicken.

As global demand for animal protein is expected to double by 2050, cellular agriculture offers a solution to meet this demand, especially as resource-intensive livestock production reaches its peak capacity. Despite recent FDA approvals for cultivated meat production, large-scale production of cultivated meat has yet to become a reality. Previous techno-economic analyses suggested economic challenges, ranging from factory to raw materials costs, casting doubt about the viability of cultivated meat production.

This work presents groundbreaking solutions, including novel filter stack perfusion that reduced factory costs, an animal component-free medium that reduced raw material costs, and continuous manufacturing that increased factory capacity, projecting an annual production of 2.14 million kg of cultivated chicken at cost parity with USDA organic chicken even for a small 50,000-liter facility.

This technological advancement could have a profound impact on animal welfare, food safety, and food security, addressing the needs of a global population increasingly affected by climate change. The study is expected to generate significant interest across multiple disciplines and resonate in popular media due to its implications for the future of humanity.

 

A new pandemic could ride in on animals we eat, researchers warn




RMIT University
Farmer and researcher with cattle on an Australian farm 

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Chris Balazs, farmer and CEO of Provenir (left), and RMIT's Professor Rajaraman Eri on an Australian farm with cattle.

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Credit: Ant Bragaglia, RMIT University




Researchers warn the animals we eat could be the gateway for a pandemic in the form of antimicrobial resistance, unleashing a wave of deadly superbugs.  

The World Health Organization estimates that drug-resistant diseases could cause up to 10 million deaths each year by 2050.

The researchers analysed this public health and food security challenge in the food animal industry in Southeast Asia for the International Journal of Food Science and Technology.

This challenge is relevant to Australia, which has strong political, economic and social ties with countries in the region. Australia marked 50 years of engagement with the Association of Southeast Asian Nations (ASEAN) at a special summit in Melbourne earlier this year.

Bioscientist Professor Rajaraman Eri and microbiologist Dr Charmaine Lloyd from RMIT University in Australia and public policy expert Dr Pushpanathan Sundram from Thailand co-wrote the journal article.

“There is a big pandemic waiting to happen in the form of antimicrobial resistance,” said Eri, who is the Associate Dean of Biosciences and Food Technology at RMIT and also a veterinarian.

“We’re going to face a situation in the world where will run out of antibiotics. That means we will not be able to treat infections.”

Asia is a hotspot of antimicrobial resistance in animals, with Southeast Asia being an epicentre, the team says.

There are more than 2.9 billion chickens, 258 million ducks, 7 million cattle, 15.4 million buffaloes, 77.5 million pigs, 13.7 million sheep and 30.6 million goats in the region, according to the Food and Agriculture Organization.

“Livestock farming, mainly for smallholders, provides employment and side income, improves household dietary components and nutritional security, and provides food and economic wellbeing for their respective nations,” said Sundram, who contributed to the research while he was at Chiang Mai University in Thailand.

The research paper highlights the Southeast Asia’s challenges associated with antimicrobial resistance and residue in animals, and points out the need to differentiate the two concepts.

Resistance occurs when microorganisms develop resistance to antimicrobial agents to which they are exposed.

“On the farm, the presence of antibiotics in food, soil, water run-off and animal waste can contribute to this resistance developing,” said Lloyd, from RMIT’s School of Science.

“The overuse and misuse of antimicrobial drugs, especially for growth promotion in healthy animals, have resulted in the increased rate of resistance.

“Since resistant bacteria in animals may be transferred to humans through the food chain or by direct contact, this transmission pathway highlights the connection between human and animal health, emphasising the need to address antimicrobial resistance in food animals.”

Food animals' residues are remnants of drugs, pesticides and other chemical substances that persist in animal tissues or products after administration or exposure to these substances.

“Veterinary drug residues commonly arise from overusing and improper use of antimicrobial agents, growth promoters and other veterinary drugs in animal husbandry practices,” Eri said.

“Efforts in the region to regulate antimicrobial use are underway, but there's growing concern over consuming products with antimicrobial residues, which can impact human health due to the presence of antibiotic-resistant microbiota and pathogens in hosts,” Sundram said.

“In Australia, we have excellent policies to take care of antimicrobial resistance, specifically, the usage of antibiotics is well regulated,” Eri said.

“But that's not the case at the global level. In many countries, anybody can buy antibiotics, whether it be for human or animal use.”

The team has six recommendations for policymakers in ASEAN countries to address antimicrobial resistance and residue in food animals:

1. Recognise the difference between residue and resistance, to tackle the resistance challenges with the right interventions in Southeast Asia's food animals.

2. Collaborate regionally and develop tailored strategies to navigate disease outbreaks, environmental concerns, residue levels and antimicrobial resistance.

3. Implement country-specific awareness campaigns, robust surveillance of residues and resistance, appropriate regulations and responsible antimicrobial use, to reduce resistance risks.

4. Foster international cooperation and initiatives to address resistance comprehensively, ensuring a united front against both residue and resistance.

5. Strengthen public health systems and preparedness.

6. Promote innovation and research in alternative antimicrobial solutions, sustainable farming practices and advanced diagnostics, to stay ahead of evolving challenges.

‘Addressing residue and resistance in food animals: a policy imperative in Southeast Asia’ is published in the International Journal of Food Science and Technology (DOI: 10.1111/ijfs.17063). Once the embargo lifts, the article will be available at this link: https://ifst.onlinelibrary.wiley.com/doi/10.1111/ijfs.17063

MULTMEDIA FOR MEDIA USE

Here’s our unlisted youtube video: https://youtu.be/I4GCG1Gl_Hs

We’ll make it public when the paper is published.

Here’s our multimedia associated with the story: https://spaces.hightail.com/space/Iq0jJui1Fs

The photos and video were taken at the farm and home of Chris Balazs, farmer and CEO of Provenir. He’s wearing the beanie in all of the photos.

The other person in the photos is RMIT University Professor Rajaraman Eri, a co-researcher of this study.

Please credit all photos and video to Ant Bragaglia, RMIT University.  

 

What really drives consumers to sign up for community-supported agriculture


Researchers show how consumers’ socio-cultural environment and expected gains and losses influence participation in community-supported agriculture



Tokyo Institute of Technology

Factors Influencing Consumers’ Decision to Participate in  Community-Supported Agriculture 

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Socio-cultural dynamics and individuals’ expectations drive CSA participation, guiding CSA promoters to increase engagement with individuals, families, peers, and the community.

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Credit: Tokyo Institute of Technology




As industrialized food markets harm the environment, sustainable food systems emerge as an effective solution. It includes reducing the distance between where the food is produced and consumed, ensuring that people eat locally produced food. One promising approach is community-supported agriculture (CSA), where consumers buy a share of the expected harvest in advance, providing farmers with financial stability and a fixed consumer base while offering consumers fresh, local food.

To expand CSA, it is crucial to understand what attracts consumers to join. Previous studies have highlighted factors like access to quality food and environmental concerns. However, these studies are limited to specific contexts and regions. So, a deeper look into diverse consumers’ complex decision-making processes is needed.

Against this backdrop, a team of researchers from Tokyo Institute of Technology, Eco-Pork Co. Ltd., and Chulalongkorn University investigated the factors influencing consumer participation in CSA. They also examined the relationship between these factors and theorized CSA participation. Led by Mr. Sota Takagi from Tokyo Institute of Technology, the team’s paper was published in Agricultural and Food Economics on 8 July 2024. 

Highlighting the motivation behind their study, Takagi says, “Socio-economical, psychological, and geographical factors influence consumers’ motivations to participate in CSA. So, a holistic understanding and systematic organization of these factors is beneficial for formulating expansion strategies, adapting the model to specific cases, and planning interventions.”

The researchers conducted a scoping review using databases like Web of Science and employed open coding to extract factors influencing consumers to participate, continue, and withdraw from CSA. They organized these factors in a diagrammatic way using the KJ method and developed a theoretical model.

According to this model, two main factors influence consumers to join CSA: the socio-cultural environment and the weighing of expected gains and losses. The socio-cultural environment, encompassing family, peers, local community, and national agricultural conditions, shapes individuals' knowledge, experience, skills, and attitudes toward food, health, and the environment. Consumers weigh expected gains (such as access to various ingredients) against expected losses, joining CSA if the expected gains outweigh the losses. This decision is also influenced by perceptions and risk tolerance shaped by the socio-cultural environment.

Previous research suggested that among expected gains, access to various ingredients was a strong motivator for CSA participation. However, intangible gains like food education, connections with people and nature, and contributions to environmental and social issues were not found to heavily sway consumers.

After joining CSA, consumers' experience, knowledge, skills, and attitudes are reshaped by the CSA community's norms. This influences their decision to stay or withdraw. So, participating in CSA is a reflexive process where consumers keep updating their decisions based on new learnings. These decisions also depend on the difference between expected and actual gains or losses and the social capital they acquire.

Takagi emphasizes, “Individuals are heavily influenced by their socio-cultural environment, where relationships with families, peers, and the community shape their attitudes and behaviors. So, CSA promoters and farmers must consider not only the individual decision-making process but also the lifestyles and values of families and peer groups and engage with them effectively.”

Let us hope these insights help local farmers promote CSA and attract consumers, thereby fostering sustainable food systems and strengthening community resilience.

As industrialized food markets harm the environment, sustainable food systems emerge as an effective solution. It includes reducing the distance between where the food is produced and consumed, ensuring that people eat locally produced food. One promising approach is community-supported agriculture (CSA), where consumers buy a share of the expected harvest in advance, providing farmers with financial stability and a fixed consumer base while offering consumers fresh, local food.

To expand CSA, it is crucial to understand what attracts consumers to join. Previous studies have highlighted factors like access to quality food and environmental concerns. However, these studies are limited to specific contexts and regions. So, a deeper look into diverse consumers’ complex decision-making processes is needed.

Against this backdrop, a team of researchers from Tokyo Institute of Technology, Eco-Pork Co. Ltd., and Chulalongkorn University investigated the factors influencing consumer participation in CSA. They also examined the relationship between these factors and theorized CSA participation. Led by Mr. Sota Takagi from Tokyo Institute of Technology, the team’s paper was published in Agricultural and Food Economics on 8 July 2024. 

Highlighting the motivation behind their study, Takagi says, “Socio-economical, psychological, and geographical factors influence consumers’ motivations to participate in CSA. So, a holistic understanding and systematic organization of these factors is beneficial for formulating expansion strategies, adapting the model to specific cases, and planning interventions.”

The researchers conducted a scoping review using databases like Web of Science and employed open coding to extract factors influencing consumers to participate, continue, and withdraw from CSA. They organized these factors in a diagrammatic way using the KJ method and developed a theoretical model.

According to this model, two main factors influence consumers to join CSA: the socio-cultural environment and the weighing of expected gains and losses. The socio-cultural environment, encompassing family, peers, local community, and national agricultural conditions, shapes individuals' knowledge, experience, skills, and attitudes toward food, health, and the environment. Consumers weigh expected gains (such as access to various ingredients) against expected losses, joining CSA if the expected gains outweigh the losses. This decision is also influenced by perceptions and risk tolerance shaped by the socio-cultural environment.

Previous research suggested that among expected gains, access to various ingredients was a strong motivator for CSA participation. However, intangible gains like food education, connections with people and nature, and contributions to environmental and social issues were not found to heavily sway consumers.

After joining CSA, consumers' experience, knowledge, skills, and attitudes are reshaped by the CSA community's norms. This influences their decision to stay or withdraw. So, participating in CSA is a reflexive process where consumers keep updating their decisions based on new learnings. These decisions also depend on the difference between expected and actual gains or losses and the social capital they acquire.

Takagi emphasizes, “Individuals are heavily influenced by their socio-cultural environment, where relationships with families, peers, and the community shape their attitudes and behaviors. So, CSA promoters and farmers must consider not only the individual decision-making process but also the lifestyles and values of families and peer groups and engage with them effectively.”

Let us hope these insights help local farmers promote CSA and attract consumers, thereby fostering sustainable food systems and strengthening community resilience.

###

About Tokyo Institute of Technology

Tokyo Tech stands at the forefront of research and higher education as the leading university for science and technology in Japan. Tokyo Tech researchers excel in fields ranging from materials science to biology, computer science, and physics. Founded in 1881, Tokyo Tech hosts over 10,000 undergraduate and graduate students per year, who develop into scientific leaders and some of the most sought-after engineers in industry. Embodying the Japanese philosophy of “monotsukuri,” meaning “technical ingenuity and innovation,” the Tokyo Tech community strives to contribute to society through high-impact research.

https://www.titech.ac.jp/english/

Institute of Science Tokyo (Science Tokyo) will be established on October 1, 2024, following the merger between Tokyo Medical and Dental University (TMDU) and Tokyo Institute of Technology (Tokyo Tech), with the mission of “Advancing science and human wellbeing to create value for and with society.”

https://www.isct.ac.jp/en

 

 

 

Habitat connectivity drives panda recovery: Study




Chinese Academy of Sciences Headquarters
A giant panda in Shaanxi Foping National Nature Reserve eating bamboo shoots 

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A giant panda in Shaanxi Foping National Nature Reserve eating bamboo shoots

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Credit: Photo by HUANG Kai




In a study published in Current Biology on Aug. 9, a research team led by Prof. WEI Fuwen from Jiangxi Agricultural University and the Institute of Zoology of the Chinese Academy of Sciences has revealed the importance of habitat connectivity in recovery of the giant panda (Ailuropoda melanoleuca).

Specifically, the study showed that conservation efforts have helped improve landscape connectivity and subsequently gene flow.

“If these processes can be sustained and improved, the panda’s path to recovery will be less encumbered by loss of genetic diversity, fostering hope that the present rate of recovery will not be stalled,” said Prof. WEI, corresponding author of the study.

In 2016, the giant panda reached a milestone rarely achieved in species conservation, i.e., downlisting by the IUCN from Endangered to Vulnerable. However, studies of ecological and population genetics mechanisms underlying population trends and conservation strategies have been lacking—making it difficult to develop next-phase conservation strategies for panda recovery.

To address this lack of information, Prof. WEI Fuwen’s team used data from China’s 3rd and 4th Giant Panda National Surveys along with DNA sampling data to better understand issues related to giant panda conservation. Their work revealed that China’s effort to mitigate anthropogenic disturbances by improving habitat quality and reducing habitat fragmentation was associated with increased panda population density.

Furthermore, the research showed that enhanced landscape connectivity overall reduced inbreeding via improved gene flow even though inbreeding increased temporarily due to high local panda density.

Findings from this study will help guide future giant panda conservation management. Specifically, it will show how a detailed examination of genetic processes can contribute to more effective strategies for recovering endangered species.

More academic freedom leads to more innovation



Study establishes link for the first time




Technical University of Munich (TUM)





The innovative strength of a society depends on the level of academic freedom. An international team involving the Technical University of Munich (TUM) has now proven this relationship for the first time. The researchers analyzed patent applications and patent citations in a sample from around 160 countries over the 1900–2015 period in relation to indicators used in the Academic Freedom Index. In view of the global decline in academic freedom over the past 10 years, the researchers predict a loss in innovative output.

In many countries scientists have experienced a loss of academic freedom in recent years. This trend has come in for criticism on the basis of fundamental principles. However, there has been no research to date on whether the degree of academic freedom also has an impact on a society’s ability to produce innovations.

For the first time an international team of researchers has studied the relationship between academic freedom and innovation output. As indicators for the quantity and quality of innovations, the researchers used patent applications and citations. Their analysis covered the 1900–2015 period in 157 countries. The team analyzed two large and respected datasets and put the results into relation: the V-Dem Dataset (Varieties of Democracy) from the V-Dem Institute at the University of Gothenburg encompasses various democracy indicators, some of which date back to 1789. They include freedom of science, which the institute, together with FAU Erlangen-Nuremberg, has also presented in the Academic Freedom Index for several years. The team obtained data on numbers of patent applications and citations from the PATSTAT database from the European Patent Office.

“Alarming signs for many countries”

The study shows that more freedom for the work of scientists results in more innovations. When the degree of academic freedom improves, this is followed by increases in the numbers of patent applications and, subsequently, in the number of patent citations.

However, the situation for academic freedom declined on a global scale during the period 2011–2021 for the first time in the last 100 years. This also applies to the group of 25 countries with the strongest science base. For that decade, the research team used the results of the study to calculate the impact of the decline. “We predict a global decline of 4–6% in innovative capability. In the leading countries, the figure is as high as 5–8%,” says study author Paul Momtaz, Professor of Entrepreneurial Finance at TUM.

“The results are an alarming sign for many countries. Those who restrict academic freedom also limit the ability to develop new technologies and processes and therefore hinder progress and prosperity,” says Paul Momtaz. “We see this trend not only in dictatorships, but also increasingly in democratic states where populist parties have gained influence.”

Numerous robustness checks confirm results

The researchers conducted several checks to confirm the robustness of the link between academic freedom and innovative output. For example they checked whether the correlation actually results from academic freedom in particular or from general freedom in a society. They also ruled out reverse causality, in other words the possibility of countries allowing more academic freedom when innovative output is too low. The results of the study were also confirmed when narrowing the perspective to countries with very high or very low numbers of patent applications, when only the post-1980 period was considered or when limiting the analysis to specific aspects of academic freedom.

Further information:

Scientists from the Technical University of Munich, Indiana University, the University of Luxembourg, the Polytechnic University of Milan and the University of Bergamo were involved in the study.

 

Study reveals the benefits and downside of fasting



Fasting helps intestinal stem cells to regenerate and heal injuries but also leads to a higher risk of cancer in mice, MIT researchers report.



Massachusetts Institute of Technology





Low-calorie diets and intermittent fasting have been shown to have numerous health benefits: They can delay the onset of some age-related diseases and lengthen lifespan, not only in humans but many other organisms.

Many complex mechanisms underlie this phenomenon. Previous work from MIT has shown that one way fasting exerts its beneficial effects is by boosting the regenerative abilities of intestinal stem cells, which helps the intestine recover from injuries or inflammation. 

In a study of mice, MIT researchers have now identified the pathway that enables this enhanced regeneration, which is activated once the mice begin “refeeding” after the fast. They also found a downside to this regeneration: When cancerous mutations occurred during the regenerative period, the mice were more likely to develop early-stage intestinal tumors.

“Having more stem cell activity is good for regeneration, but too much of a good thing over time can have less favorable consequences,” says Omer Yilmaz, an MIT associate professor of biology, a member of MIT’s Koch Institute for Integrative Cancer Research, and the senior author of the new study. 

Yilmaz adds that further studies are needed before forming any conclusion as to whether fasting has a similar effect in humans.

“We still have a lot to learn, but it is interesting that being in either the state of fasting or refeeding when exposure to mutagen occurs can have a profound impact on the likelihood of developing a cancer in these well-defined mouse models,” he says.

MIT postdocs Shinya Imada and Saleh Khawaled are the lead authors of the paper, which will appear in Nature.

Driving regeneration

For several years, Yilmaz’s lab has been investigating how fasting and low-calorie diets affect intestinal health. In a 2018 study, his team reported that during a fast, intestinal stem cells begin to use lipids as an energy source, instead of carbohydrates. They also showed that fasting led to a significant boost in stem cells’ regenerative ability.

However, unanswered questions remained: How does fasting trigger this boost in regenerative ability, and when does the regeneration begin? 

“Since that paper, we've really been focused on understanding what is it about fasting that drives regeneration,” Yilmaz says. “Is it fasting itself that's driving regeneration, or eating after the fast?”

In their new study, the researchers found that stem cell regeneration is suppressed during fasting but then surges during the refeeding period. The researchers followed three groups of mice — one that fasted for 24 hours, another one that fasted for 24 hours and then was allowed to eat whatever they wanted during a 24-hour refeeding period, and a control group that ate whatever they wanted throughout the experiment.

The researchers analyzed intestinal stem cells’ ability to proliferate at different time points and found that the stem cells showed the highest levels of proliferation at the end of the 24-hour refeeding period. These cells were also more proliferative than intestinal stem cells from mice that had not fasted at all.

“We think that fasting and refeeding represent two distinct states,” Imada says. “In the fasted state, the ability of cells to use lipids and fatty acids as an energy source enables them to survive when nutrients are low. And then it's the postfast refeeding state that really drives the regeneration. When nutrients become available, these stem cells and progenitor cells activate programs that enable them to build cellular mass and repopulate the intestinal lining.”

Further studies revealed that these cells activate a cellular signaling pathway known as mTOR, which is involved in cell growth and metabolism. One of mTOR’s roles is to regulate the translation of messenger RNA into protein, so when it’s activated, cells produce more protein. This protein synthesis is essential for stem cells to proliferate. 

The researchers showed that mTOR activation in these stem cells also led to production of large quantities of polyamines — small molecules that help cells to grow and divide.

“In the refed state, you've got more proliferation, and you need to build cellular mass. That requires more protein, to build new cells, and those stem cells go on to build more differentiated cells or specialized intestinal cell types that line the intestine,” Khawaled says. 

Too much of a good thing

The researchers also found that when stem cells are in this highly regenerative state, they are more prone to become cancerous. Intestinal stem cells are among the most actively dividing cells in the body, as they help the lining of the intestine completely turn over every five to 10 days. Because they divide so frequently, these stem cells are the most common source of precancerous cells in the intestine. 

In this study, the researchers discovered that if they turned on a cancer-causing gene in the mice during the refeeding stage, they were much more likely to develop precancerous polyps than if the gene was turned on during the fasting state. Cancer-linked mutations that occurred during the refeeding state were also much more likely to produce polyps than mutations that occurred in mice that did not undergo the cycle of fasting and refeeding.

“I want to emphasize that this was all done in mice, using very well-defined cancer mutations. In humans it's going to be a much more complex state,” Yilmaz says. “But it does lead us to the following notion: Fasting is very healthy, but if you're unlucky and you're refeeding after a fasting, and you get exposed to a mutagen, like a charred steak or something, you might actually be increasing your chances of developing a lesion that can go on to give rise to cancer.”

Yilmaz also noted that the regenerative benefits of fasting could be significant for people who undergo radiation treatment, which can damage the intestinal lining, or other types of intestinal injury. His lab is now studying whether polyamine supplements could help to stimulate this kind of regeneration, without the need to fast. 

The research was funded in part by a Pew-Stewart Trust Scholar award, the Marble Center for Cancer Nanomedicine, the Koch Institute-Dana Farber/Harvard Cancer Center Bridge Project, and the MIT Stem Cell Initiative.

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Written by Anne Trafton, MIT News