Doctor Who, Women's Tears, Gut Bacteria
Welcome to this month's edition of "Briefly Science," your go-to source for the latest and most intriguing academic research findings.
In this issue, we dive into a diverse array of topics, from the calming power of human female tears to the influence of ancient interbreeding on our circadian rhythms.
We unravel the mysteries of infant consciousness and examine the effects of maternal heat stress on birth weight.
Our journey also takes us to the unique traits of reindeer, the impact of B-vitamin and Vitamin D levels during pregnancy, and the fascinating connection between brain function, gut bacteria, and weight loss.
Each article in this newsletter has been meticulously summarised to make complex research papers easily accessible and understandable to our college student audience.
Enjoy your journey through the marvels of science!
Estimated read time: 20 minutes.
1: A Chemical Signal in Human Female Tears: A Natural Defence Against Aggression in Men
Read the full paper: A chemical signal in human female tears lowers aggression in males
Authors: Shani Agron, Claire A. de March, Reut Weissgross, Eva Mishor, Lior Gorodisky
Published: December 21st, 2023
Have you ever wondered why some women's tears have a calming effect on men?
Researchers have discovered that human female tears contain a special chemical signal that can lower aggression in males.
Similar to how rodents use their tears to block male aggression, tears from women have been found to reduce testosterone levels in men. Since reduced testosterone is associated with reduced aggression, the researchers hypothesised that human tears may act in a similar way to prevent aggressive behaviour in men.
To test this hypothesis, the researchers conducted an experiment using a well-established behavioural test. They found that when men sniffed tears from emotional women, without perceiving any odour, their aggression levels dropped by a significant 43.7%. Intrigued by this result, the researchers investigated the underlying mechanisms in the brain.
In vitro experiments were performed on human olfactory receptors, revealing that tears activate four specific receptors in a dose-dependent manner. This suggests that there are specific molecular interactions occurring between the tears and these receptors.
To further investigate the brain's response, the researchers carried out the experiment while simultaneously conducting functional brain imaging. Astonishingly, they discovered that sniffing tears increased the connectivity between the brain regions responsible for the sense of smell and those involved in aggression. This increased connectivity led to an overall decrease in the neural activity associated with aggressive behaviour.
This research seems to indicate that female tears have a remarkable power to reduce male aggression, similar to what occurs in rodents.
These findings suggest that tears might be a natural protective mechanism found in mammals, providing a chemical shield against aggression.
Our understanding of the complex relationship between tears, olfaction, and aggression has broad implications for various fields ranging from psychology to neurobiology.
2: Archaic Interbreeding Influenced Our Body Clock
Read the full paper: Archaic Introgression Shaped Human Circadian Traits
Authors: Keila Velazquez-Arcelay, Laura L Colbran, Evonne McArthur, Colin M Brand, David C Rinker
Published: December 14th, 2023
DOI: 10.1093/gbe/evad203
When our ancient ancestors left Africa and interbred with Neanderthals and Denisovans, they incorporated the DNA of these archaic hominins into their own genetic makeup.
This process may have accelerated our adaptation to life in Eurasia, where we faced different environmental conditions, such as less intense sunlight and more seasonal variations. However, we are still unsure if these archaic genetic contributions played a role in shaping our sleep and wake cycle, also known as our chronotype.
To shed light on this, researchers compared the genetic sequences and expression of circadian genes between us and our archaic relatives.
They identified several circadian genes that differed between archaic hominins and modern humans, suggesting that the archaic DNA could affect our circadian gene expression.
Further investigation revealed that some of these archaic genetic variants are associated with differences in our chronotypes.
Surprisingly, the archaic DNA seems to influence us to be more inclined towards morningness, which aligns with adaptations seen in other species living in high latitude regions.
Additionally, the researchers found evidence of genetic variants specific to certain locations, suggesting that natural selection may have favoured certain chronotypes in different geographic regions. This adds to the understanding of how our body clock has evolved in response to the changing environments we have inhabited throughout history.
These findings highlight the role of archaic interbreeding in shaping our circadian biology and provide insights into the genetic basis of our chronotypes.
Understanding how our genes influence our sleep-wake patterns can have practical implications for various aspects of our lives, including shift work schedules and personal sleep preferences.
It also reminds us that our genetic makeup is a mosaic of multiple ancient hominins, contributing to the diversity and uniqueness of the human species.
In conclusion, our body clock is not solely a product of our modern human ancestors. The interbreeding with archaic hominins has left a genetic imprint on our circadian genes, affecting our chronotype and ultimately, our daily rhythms.
3: Consciousness in Infants: Unveiling the Mysterious World of Infant Experience
Read the full paper: Consciousness in the cradle: on the emergence of infant experience
Authors: Tim Bayne, Joel Frohlich, Rhodri Cusack, Julia Moser, Lorina Naci
Published: December 1st, 2023
Understanding how infants experience the world has become a fascinating area of research in the study of consciousness.
Scientists are piecing together evidence from various studies on brain connectivity, attention, sensory integration, and responses to unfamiliar stimuli.
This growing body of research suggests that consciousness is likely to exist in the early stages of infancy, and might even emerge before a baby is born. The findings shed light on what infants might be aware of and how their understanding of the world takes shape.
Some intriguing clues have emerged regarding the content and structure of infant consciousness. Researchers have found that infants possess advanced neural networks that allow different regions of the brain to communicate and coordinate their activities. Moreover, their ability to direct their attention towards specific stimuli and integrate information from multiple senses indicates a level of conscious processing.
Surprisingly, findings also suggest that consciousness could potentially arise even prior to birth, sparking a deep curiosity about the experiences of the unborn child.
As we delve deeper into this fascinating realm, scientists are starting to unravel the mysteries of what infants perceive and recognise.
By studying their responses to unfamiliar or unexpected events, researchers gain insight into the content of their consciousness.
Additionally, the structure of their experiences is beginning to be unravelled, offering clues as to how infants form their understanding of the world around them.
Understanding the early development of consciousness in infants not only illuminates the incredible capabilities of the developing brain but also raises profound questions about the nature of human experience itself.
This research provides a window into the foundations of our conscious awareness and presents us with an opportunity to reflect on our own journey from infancy to adulthood.
By comprehending the emergence of consciousness in its earliest stages, we gain a deeper understanding of what it means to be conscious beings.
4: Critical Periods of Maternal Exposure to Heat Stress and Birth Weight in Western Australia
Read the full paper: Critical Windows of Maternal Exposure to Biothermal Stress and Birth Weight for Gestational Age in Western Australia
Authors: Sylvester Dodzi Nyadanu, Gizachew A. Tessema, Ben Mullins, Kevin Chai, Maayan Yitshak-Sade
Published: December 27th, 2023
DOI: 10.1289/EHP12660
Do you know that the temperature your mother was exposed to during pregnancy could affect your birth weight?
A group of researchers in Western Australia studied this intriguing topic and published their findings in a recent research paper. Previous studies have explored the link between the environment and birth weight, but they mainly focused on overall temperature rather than a specific measure known as the Universal Thermal Climate Index (UTCI).
The team of researchers examined over 385,000 term births in Western Australia, spanning from the year 2000 to 2015. They analysed data on maternal exposure to UTCI from 12 weeks before conception until birth. They discovered some fascinating patterns that shed light on critical periods during pregnancy when exposure to extreme biothermal stress could impact birth weight.
Their results showed that high UTCI exposures during late gestational periods had the most significant effect on birth weight. Specifically, the sixth to the tenth month of pregnancy exhibited the highest hazard for both small (SGA) and large (LGA) for gestational age babies. Even exposure throughout the entire pregnancy had an impact, with the second trimester being the riskiest for SGA and the first trimester for LGA.
But here's where it gets more interesting. The researchers also examined the vulnerability of certain groups based on sociodemographic factors. They found that male babies, mothers who were non-Caucasian, smokers, aged 35 or older, and rural residents faced a higher risk of being affected by extreme biothermal stress. This means that these groups need to be more cautious during critical periods of pregnancy to ensure the best possible birth outcomes.
Understanding how environmental factors like heat stress can impact birth weight is crucial for promoting healthier pregnancies. By shedding light on these critical periods of vulnerability, healthcare providers and policymakers can develop strategies to support pregnant women during specific times throughout their pregnancies.
Ultimately, this research contributes to our understanding of how the environment affects human health and highlights the importance of targeted interventions for at-risk populations.
5: Reindeer: Unveiling the Mysteries of their Strange Traits
Read the full paper: Reindeer and the quest for Scottish enlichenment
Authors: Nathaniel J. Dominy, Catherine Hobaiter, Julie M. Harris
Published: December 15th, 2023
Have you ever wondered what makes reindeer so unique?
These fascinating creatures possess extraordinary features that set them apart from other animals. For instance, reindeer are the only mammals with a special light-reflecting layer in their eyes, known as tapetum lucidum, that changes colours.
Additionally, they are the only ruminants with a diet primarily consisting of lichens, a peculiar type of plant.
Interestingly, the reindeer's eyes also have the ability to process a significant amount of ultraviolet (UV) light, even more than humans! But why would a daytime-dwelling Arctic mammal need such UV sensitivity?
One theory suggests that this exceptional visual capability may enhance their detection of UV-absorbing lichens against the backdrop of UV-reflecting snows, particularly in the extended twilight hours of winter.
To delve into this notion and expand our knowledge of reindeer visual ecology, researchers embarked on a mission to investigate the eating habits of reindeer residing in Scotland's breathtaking Cairngorms National Park. They studied the reflectance patterns of several types of ground-growing and shrubby lichens, which form a vital part of these reindeer's diets.
By uncovering the secrets of reindeer vision and their affinity for lichens, this research contributes to our understanding of these magnificent creatures and their environment.
It sheds light on their unique adaptations and the reasons behind their peculiar traits. Reindeer play an essential ecological role, and by comprehending their visual abilities and dietary preferences, we can better appreciate their impact on the delicate balance of their Arctic habitats.
So, the next time you spot a reindeer, take a moment to marvel at their remarkable qualities. Consider how their eyes, capable of processing UV light, help them forage for lichens in the snowy wilderness.
The mysteries of reindeer are yet to be fully unraveled, but by studying them, we gain valuable insights into the complexities of the natural world.
Let us embrace the enigmatic reindeer and appreciate their contribution to the magic of our planet.
6: Understanding the Impact of B-Vitamin and Vitamin D Levels on Pregnancy and Beyond
Authors: Keith M. Godfrey, Philip Titcombe, Sarah El-Heis, Benjamin B. Albert, Elizabeth Huiwen Tham
Published: December 5th, 2023
Maternal vitamin levels before, during, and after pregnancy play a crucial role in pregnancy outcomes and the development of offspring.
While studies have examined changes in vitamin status during pregnancy, there is a limited understanding of how vitamin levels fluctuate from preconception through pregnancy and postpartum. Additionally, the effectiveness of vitamin supplementation during pregnancy remains uncertain.
In this study, the researchers analysed data from the NiPPeR trial, a randomised controlled trial, to investigate the longitudinal patterns of maternal vitamin status and the influence of supplementation.
The NiPPeR trial involved 1,729 women from the United Kingdom, Singapore, and New Zealand, aged 18 to 38, who were planning to conceive.
The participants were randomly assigned to receive either a standard vitamin supplement (control group) or an enhanced vitamin supplement (intervention group) starting from preconception and continuing throughout pregnancy.
The primary focus of the study was to evaluate glucose tolerance at 28 weeks of gestation, while this secondary analysis focused on the reduction of maternal micronutrient insufficiency in riboflavin, vitamin B6, vitamin B12, and vitamin D before and during pregnancy.
To assess vitamin status, the researchers measured plasma concentrations of B-vitamins, vitamin D, and markers of insufficiency/deficiency at different stages: recruitment, 1 month after starting the intervention preconception, in early and late pregnancy, and postdelivery. They compared the results between the control and intervention groups.
The findings revealed that at recruitment, approximately 30% of participants had marginal or low plasma folate levels, and this proportion decreased significantly by 28 weeks of gestation in the intervention group. However, in the control group, over half of the participants developed low vitamin B6 concentrations in late pregnancy.
Overall, this study provides valuable insights into the longitudinal changes in maternal vitamin status from preconception through pregnancy to post-delivery and the impact of vitamin supplementation.
The results highlight the importance of adequate vitamin levels for a healthy pregnancy and emphasise the potential benefits of targeted supplementation.
These findings can inform healthcare professionals and individuals planning to conceive about the significance of maintaining optimal vitamin status for the well-being of both mother and child.
7: Dynamical Changes in Brain and Gut Bacteria During Weight Loss: A Fascinating Connection
Read the full paper: Dynamical alterations of brain function and gut microbiome in weight loss
Authors: Jing Zhou, Xiaoling Wu, Tianyuan Xiang, Fei Liu, Hui Gao
Published: December 20th, 2023
Losing weight has always been a challenge, but recent research sheds light on a new theory linking brain function and gut bacteria to successful weight loss.
Intermittent energy restriction (IER) is a popular weight loss strategy, but little is known about how it affects the intricate interplay between our brain, gut, and microbiome.
In this study, researchers investigated the effects of IER on 25 obese individuals who successfully lost weight over a two-month period. They used functional magnetic resonance imaging (fMRI) to observe brain activity and metagenomic sequencing to examine different microbial species in fecal samples.
The research findings were captivating.
As the participants underwent IER, specific brain regions associated with obesity showed a consistent reduction in activity over time. These regions included the inferior frontal orbital gyrus, involved in cognitive control, the putamen, related to emotions and learning, and the anterior cingulate cortex, involved in sensory processing.
Furthermore, the researchers observed an intriguing dynamic alteration in the gut bacteria composition.
Throughout the weight loss journey, the abundance of E. coli, a common gut bacterium, decreased, while the levels of obesity-related microbes such as Faecalibacterium prausnitzii, Parabacteroides distasonis, and Bacterokles uniformis increased.
The researchers went a step further and discovered a remarkable correlation between changes in gut bacteria and alterations in brain activity. This suggests a close interaction between specific gut bacteria and the brain, indicating that communication between these two integral systems influences weight loss progress.
Understanding this intricate connection between the brain, gut bacteria, and weight loss could potentially offer beneficial insights into developing more effective weight loss strategies. By targeting specific gut microbes associated with obesity and modulating brain activation in related regions, future interventions may enhance weight loss efforts.
This research opens the door to exciting possibilities for individuals struggling with excess weight. By recognising and harnessing the relationships between our brains, gut bacteria, and weight loss, we can embark on a journey towards a healthier and happier life.
8: The Impact of Doctor Who on Public Health: A Festive Study
Read the full paper: Effect of a doctor working during the festive period on population health: natural experiment using 60 years of Doctor Who episodes (the TARDIS study)
Authors: Richard D Riley
Published: December 18th, 2023
Do you believe in the power of fictional doctors?
Well, it seems like Doctor Who might just have a positive effect on population health during the festive period.
A group of researchers took on the mission to investigate this intriguing phenomenon using a unique natural experiment. They examined 60 years of Doctor Who episodes to see if the fictional doctor's adventures had any influence on mortality rates in England, Wales, and the UK.
The team carefully analysed the annual mortality rates from 1963, the year Doctor Who first hit the small screen. They used a sophisticated time series analysis method, considering various factors that could impact mortality rates. In particular, they focused on the episodes broadcast during the previous festive period, from 24 December to 1 January, when many people gather around the TV with loved ones.
Surprisingly, the researchers discovered a fascinating association between the airing of Doctor Who episodes during the festive period and decreased mortality rates. The impact was especially notable when episodes premiered on Christmas Day.
In England and Wales, these Christmas episodes were linked to 0.60 fewer deaths per 1000 person years, while the UK as a whole experienced 0.40 fewer deaths per 1000 person years. The researchers also observed a significant reduction in mortality rates starting from 2005, when Doctor Who became an annual Christmas tradition.
These findings suggest that the presence of the heroic Doctor during the festive season might just have a real-life impact on our health. It serves as a reminder that access to healthcare should never be taken for granted, even if it comes from a fictional character.
Considering the potential influence of Doctor Who on public health, the researchers propose that the BBC and Disney+ seriously consider broadcasting new episodes every festive period, ideally on Christmas Day.
So, next time you gather with family and friends on December 25th to watch the Doctor save the day, appreciate the possibility that this festive tradition may actually be making a positive difference in our lives.
9: Why Some People on a Low-Carb Diet Have Different Cholesterol Levels: New Findings
Read the full paper: Thyroid markers and body composition predict LDL-cholesterol change in lean healthy women on a ketogenic diet: experimental support for the lipid energy model
Authors: Isabella D. Cooper, Claudio Sanchez-Pizarro, Nicholas G. Norwitz, David Feldman, Yvoni Kyriakidou
Published: December 21st, 2023
Ever wondered why some people on a low-carb diet experience changes in their cholesterol levels while others don't?
Well, researchers may have cracked the code. In a recent study, scientists investigated the factors that influence LDL-cholesterol changes in lean and healthy women following a ketogenic diet.
It turns out that body composition and markers of energy metabolism play a significant role in predicting these cholesterol changes. The study involved ten premenopausal women who had been following a low-carb, high-fat ketogenic diet for at least six months.
The researchers conducted a three-phase study, where the participants went through periods of continued nutritional ketosis, reintroduction of carbohydrates to suppress ketosis, and then a return to nutritional ketosis. Each phase lasted for 21 days.
The results showed that certain factors influenced the changes in LDL-cholesterol levels. Interestingly, body composition metrics, such as the amount of lean muscle mass and fat mass, along with markers of thyroid hormone levels, were closely linked to LDL-cholesterol changes. Surprisingly, saturated fat intake, insulin resistance, and other hormone markers did not show a significant association.
The findings suggest that lean individuals following a low-carb diet may experience changes in LDL-cholesterol levels due to alterations in body composition and energy metabolism, not solely due to their consumption of saturated fats. This aligns with the lipid energy model, which suggests that carbohydrate restriction leads to an increase in systemic lipid trafficking to meet the body's energy needs.
Understanding the factors that influence cholesterol changes in individuals on a low-carb diet is crucial for providing tailored dietary recommendations and managing the potential health risks associated with such changes.
Further research in larger and more diverse populations is needed to confirm these findings and explore the underlying mechanisms.
So, if you're considering adopting a low-carb diet and want to understand how it might impact your cholesterol levels, remember that factors like your body composition and energy metabolism could potentially play a role. As always, it's essential to consult with healthcare professionals before making any significant dietary changes.
Stay curious, keep questioning, and continue exploring the fascinating realm of science. Until next time, happy reading!
Claudia.