Light Dark Matter Can Be Produced from Inflaton Decay (Astronomy / Cosmology)

A long-standing puzzle of particle physics and cosmology is the origin of dark matter (DM). The DM is known to be (very) weakly coupled to the standard model (SM) particles, stable, cold, and abundant in the present Universe. However the mass, the interactions, and the production mechanism are still not clear.

The DM mass may be small, in which case the stability (or longevity) is easily explained due to the kinematics (or suppressed decay width). From the point of view of DM direct detections, if the mass is small enough, the recoil energy of a nucleon via the DM-nucleon scattering is highly suppressed, which is consistent with the null result of the direct detection experiments for WIMP. Nevertheless a light DM can be searched for from different approaches in the near future.

A difficulty of the light DM is the production in the early Universe. If it were produced thermally, like the WIMP, the number density cannot be larger than that of the SM photons, and may be too small unless the mass is larger than eV. Moreover, it may be too hot to be consistent with structure formation. For instance a thermal relic of sterile neutrino has to be heavier than 2-5 keV from Lyman-α forest data. If it is produced from freeze-in the bound is even severer.

The production of light DM has been discussed in many studies. Like the one in which an axion/axion-like particle (ALP) can be produced via the misalignment mechanism. A light hidden photon DM can be produced gravitationally. (Gravitational effect during inflation is also important for the axion/ALP DM). The hidden photon DM can be produced from a parametric/tachyonic resonance by coupling to the QCD axion. In addition, the axion (or ALP) production from the parametric resonance of another scalar field was also discussed by Mazumdar et al. & Harigaya et al. in their paper. A light DM may be produced by the decays of heavy particles at an early epoch.

Now, Takeo Moroi and Wen Yina in their recent paper, explore new possibility of light DM production. They proposed that light DM is produced from the decay of an inflaton (or more generically, an oscillating scalar field) which reheats the Universe.

They have showed that if the inflaton coupling to the SM sector has a sizable strength, the reheating temperature (Tr) due to the inflaton decay can be comparable to or higher than the inflaton mass (mφ). If Tr ≥ mφ, then the dark matter produced by the inflaton has a momentum smaller than those of particles in the thermal bath (consisting of the standard model particles), assuming that the interaction of the DM with the SM particles or itself is negligibly weak. It can help the DM produced by the decay to be cold enough to be consistent with the Lyman-α bound on warm DMs even if the DM mass is smaller than O(1) keV.

Fig. 1: The maximal r by varying ΛG [red line]. The corresponding reheating temperature and inflaton mass are also shown in green and blue solid lines, respectively.

They have also showed that, if the DM is bosonic, the production of the DM from the inflaton decay can be enhanced due to the effect of the stimulated emission, like the LASER. The mechanism, called DASER (i.e, the DM amplification by stimulated emotion of radiation), can significantly enhance the DM abundance and can make light bosonic DM scenarios viable. In addition, if the DM is fermionic, the DM produced by the decay may form Dirac sea. The DASER and Dirac sea DMs produced by the inflaton decay may be searched for by future observations of the 21cm lines. The DMs produced by the above mentioned mechanism (i.e. from DASER) have null isocurvature perturbations.

Finally, they comment that the DMs produced in the present scenarios may have very special momentum distribution, and the information about the production mechanism discussed in their paper may be embedded in the momentum distribution of the DM. For example, the momentum of the bosonic DM produced by the DASER mechanism would have sharp peak at the IR mode. In addition, momentum distribution of the modes produced during the preheating depends on the thermal history during the preheating. One may probe the reheating phase or preheating phase if the information about the momentum distribution of the DM becomes available. For this purpose, they concluded that further study of the structure formation with non-standard momentum distribution of the DM is needed.

References: Takeo Moroi, Wen Yin, “Light Dark Matter from Inflaton Decay”, ArXiv, pp. 1-31, 2020. https://arxiv.org/abs/2011.09475v1

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Scientists Develop A Coating For Socks That Kills Bacteria And Neutralises Unpleasant Odours (Material Science)

  • Cadets in Thailand have successfully tested the anti-bacterial coatings for socks
  • They’re made from zinc oxide nanoparticles – known to inhibit bacterial growth 
  • The coating is harmless to skin and can reduce pitted keratolysis, a skin infection

Scientists in Thailand have developed a coating for socks that kills bacteria and cures smelly feet.

The coating, made from zinc oxide nanoparticles (ZnO-NPs), can prevent bromodosis, better known as foot odour, and pitted keratolysis, a bacterial infection. 

Antibacterial properties of ZnO-NPs, which are harmless to human skin, make the coating suitable to be incorporated into textiles, including socks, the scientists say. 

The coated socks were successful trialled on cadets by researchers at Siriraj Hospital, Mahidol University in Thailand.

Socks coated in zinc oxide nanoparticles (ZnO-NPs) can prevent bromodosis (foot odour) and pitted keratolysis (bacterial infection causing smelly feet). Pictured, cadets having their feet analysed for the effects of the bacteria-killing ZnO-NPs

WHAT IS PITTED KERATOLYSIS?

Pitted keratolysis is a common skin disease, caused by various gram-positive bacteria including Corynebacterium species, Kytococcus sedentarius, Dermatophilus congolensis and Actinomyces species. 

These bacteria ‘eat’ the keratin on the skin of the soles of the feet, creating small tunnels, giving a ‘pitted’ appearance and unpleasant ‘cheesy’ foot malodour. 

It is commonly found in young male adults, especially in soldiers, miners and athletes. 

The researchers were following up from a 2018 study into the prevalence of fungal foot infection in Thai naval cadets. 

‘While completing an internship as a naval officer in the medical department, I saw a high number of foot infections in military personnel,’ said lead study author Dr Punyawee Ongsri. 

‘I wanted to find a way to prevent and treat these fungal and bacterial infections and those conditions associated. 

‘Previous studies had demonstrated zinc oxide nanoparticles’s antibacterial properties therefore [we wanted] to test the efficacy of this new technology in a real-life setting.’

Researchers trailed the coated socks on 148 cadets at the Thai Naval Rating School, seeing as bromodosis and pitted keratolysis are a common complaint among military personnel. 

Foot lesions, including pitted keratosis, occurr in more than a third – 38.5 per cent – of naval cadets in Thailand, according to the 2018 study.  

Cadets were assigned to a 14-day field training course and were then randomly assigned to either a ‘ZnO-NP-coated group’ or an ‘uncoated-sock’ group, who just wore standard socks. 

Cadets self-assessed their foot odour levels and completed questionnaires evaluating behavioural risk, while dermatologists also performed foot examinations.

Pitted keratolysis is a bacterial skin infection that affects the soles of the feet and sometimes less the palms of the hands. It is one of the causes of smelly feet. It is characterised by whitish skin and clusters of punched-out pits

The cadets, who were requested to only wear their assigned socks provided, had their odour levels assessed upon completion of the training course. 

The study demonstrated that those with the ZnO-NP-coated socks had significantly fewer foot odours. 

This was compared to an uncoated-sock group who experienced more intense foot odour with a ‘greater negative effect on their daily life’, the experts report.

They also found that participants with the uncoated-socks were more likely to develop pitted keratolysis compared to those with the ZnO-NP-coated-socks.

Cadets were randomly assigned to either a ‘ZnO-NP-coated group’ or an ‘uncoated-sock’ group, who just wore standard socks

‘Our results prove the efficacy of ZnO-NP-coated socks in preventing bromodosis and inhibiting the development of pitted keratolysis,’ said Dr Ongsri. 

‘These socks could provide a new primary prevention option for both military personnel and those susceptible to these embarrassing and unpleasant conditions. 

‘We are continuing our research with other textiles and hope to treat and prevent the growth of bacterial and fungal infections.’

The findings are being presented at the 29th European Academy of Dermatology and Venereology (EADV) Congress, which has moved online due to the coronavirus pandemic.

References: Prevalence and Clinical Correlation of Superficial Fungal Foot Infection in Thai Naval Rating Cadets – PubMed

Provided by Mahidol University

Chemicals Found In Daily-use Products Could Decrease COVID-19 Vaccine’s Effectiveness (Medicine)

Researchers worry PFAS, commonly found in the bodies of Americans, will reduce the immunization’s effectiveness.

The successful uptake of any vaccine for Covid-19, a crucial step in returning a sense of normalcy after a year ravaged by the coronavirus pandemic, could be hindered by widespread contamination from a range of chemicals used in everyday products.

Small amounts of per- and polyfluoroalkyl (or PFAS) chemicals are commonly found in the bodies of people in the US, as well as several other countries. These man-made chemicals, used in everything from non-stick pans to waterproof clothes to pizza boxes, have been linked to an elevated risk of liver damage, decreased fertility and even cancer.

But scientists warn some of these chemicals can also cause another little-known but potentially significant defect by reducing the effectiveness of certain administered vaccines. This impediment could cast a shadow over efforts to roll out a Covid-19 vaccine to enough people that restrictions on day-to-day life are eased.

“At this stage we don’t know if it will impact a corona vaccination, but it’s a risk,” said Philippe Grandjean, an adjunct professor of environmental health at the Harvard School of Public Health. “We would have to cross our fingers and hope for the best.”

Research led by Grandjean has found that children exposed to PFAS had significantly reduced antibody concentrations after given tetanus and diphtheria vaccinations. A follow-up study of adult healthcare workers found similar results. Meanwhile, a certain type of PFAS, called perfluorobutyrate (or PFBA), accumulates in the lungs and can heighten the severity of illness suffered by people who are infected with Covid-19, separate research by Grandjean, yet to be peer-reviewed, has suggested.

German company BioNTech and the US pharmaceutical giant Pfizer provoked a surge of optimism over an impending Covid vaccine after announcing a contender was 90% effective in preventing people from falling ill with the disease. The scientist behind the vaccine has predicted it will “bash the virus over the head” and help lift the pandemic that has crippled much of the world since the beginning of the year.

The Pfizer vaccine is based on messenger RNA genetic material and it’s uncertain if PFAS contamination would disrupt its efficacy in patients. But there are several other vaccine contenders that are formulated around the protein spikes of the virus, similar to vaccines for tetanus and diphtheria, and they may well also have poor results in people who have ingested PFAS.

“People with high exposure to PFAS have a non-protective and very low antibody levels after four vaccinations for diphtheria and tetanus,” Grandjean said. “So if a vaccine for Covid is similar, the PFAS will likely inhibit the response from a vaccine. But it is an unknown at this stage.”

The US president-elect, Joe Biden, has promised to crack down on PFAS pollutants by classifying them as hazardous substances. It is estimated more than 200 million Americans eat food and drink water laced with PFAS, known as “forever chemicals” as they linger long in the body, with hotspots found in areas around military bases where the chemicals are used in firefighting foam.

Despite this, only a few states require drinking water to be largely free from PFAS, a situation that a Biden-controlled Environmental Protection Agency will probably intervene in with new federal limits.

Any new regulation of PFAS will now have an added urgency, with a Covid vaccine expected for the vast majority of Americans by mid-2021. “I do worry constantly about exposure for both known and unknown PFAS, and the impacts they are having on both our immune systems and on our health in general,” said David Andrews, a senior scientist at the Environmental Working Group. “PFAS exposure is an urgent public health crisis.”

References: Philippe Grandjean, Carsten Heilmann, […], and Esben Budtz-Jørgensen, “Estimated Exposures to Perfluorinated Compounds in Infancy Predict Attenuated Vaccine Antibody Concentrations at Age 5-Years”, Journal of Immunotoxicology, 2020. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6190594/

Provided by Guardian

Double Stars Tell A Story About The Evolution Of The Milky Way (Astronomy)

The orbits of double stars are a direct consequence of how the Milky Way evolved with time. This important observation will constrain the Galactic evolutionary history in new ways, Humboldt Fellow Dr. Joris Vos from the Institute of Physics and Astronomy believes.

Artists view of mass loss from a red giant star due to gravitational pull of its solar-like companion. Image credit: Joris Vos

Double star systems consisting of small hot blue stars and stars similar to our sun are the research objects of a study highlighted recently in “Astronomy & Astrophysics”. In this study, authors from the University of Potsdam, Lund University (Sweden) and Universidad de Valparaíso (Chile) report about stars orbiting a common center of mass. The small hot blue stars, called hot subdwarf B stars, are cores of red giant stars which have recently lost their outer layers due to gravitational pull of their solar-like companions and ignited helium. Our Sun will also become a red giant star once it burns up its hydrogen fuel. “The orbits of the binaries show a strong relationship between their periods and masses which has been very hard to explain with known models of stellar interactions”, says Joris Vos from the Stellar Astrophysics Group, the first author of the study, “We have found that the orbits of our binaries are a direct consequence of how our Galaxy evolved with time.”

When the Milky Way formed, the stars in it contained very little iron, whereas the presently-formed stars are more iron-rich like the Sun. The difference in iron content makes red giant stars, as well as the resulting orbits, larger by up to 30 per cent. The orbital periods of the binaries can be fully explained by a combined model of stellar interactions and the temporal evolution of the amount of iron in the Milky Way. Joris Vos points out: “This is the first time we have demonstrated that there is an observable connection between the chemical history of our Galaxy and observations and modelling of evolved binary stars.”

Both the University of Potsdam and the Lund University are involved in the 4MOST survey (ESO) that will deliver spectra, compositions and ages of twenty million stars. Lund University is further involved in the Gaia mission (ESA) that has mapped the positions of more than two billion stars in the Galaxy. “We expect that the new detailed models of our Galactic history will and should be used to make detailed predictions of the binary populations in it. This, in turn, should be connected to the various observations of Milky Way binaries. Finally, we hope to show the community that there is a lot of new information which can be gained by having more interdisciplinary communication between the different fields of astronomy”, Joris Vos sums up.

Link to Publication: J. Vos, A. Bobrick and M. Vučković (2020): Observed binary populations reflect the Galactic history – Explaining the orbital period-mass ratio relation in wide hot subdwarf binaries,
A&A, 641 (2020) A163. https://www.aanda.org/articles/aa/abs/2020/09/aa37195-19/aa37195-19.html https://doi.org/10.1051/0004-6361/201937195

Provided by University of Potsdam

Go (Over) Easy On the Eggs: ‘Egg-cess’ Consumption Linked to Diabetes (Food)

Scrambled, poached or boiled, eggs are a popular breakfast food the world over. Yet the health benefits of the humble egg might not be all they’re cracked up to be as new research from the University of South Australia shows that excess egg consumption can increase your risk of diabetes.

Eat one or more eggs per day and you increase your risk of diabetes by up to 60 per cent. ©University of South Australia

Conducted in partnership with the China Medical University, and Qatar University, the longitudinal study (1991 to 2009) is the first to assess egg consumption in a large sample of Chinese adults.

It found that people who regularly consumed one or more eggs per day (equivalent to 50 grams) increased their risk of diabetes by 60 per cent.

With the prevalence of diabetes in China now exceeding 11 per cent – above that of the global average of 8.5 per cent – diabetes has become a serious public health concern.

The economic impact of diabetes is also significant, accounting for 10 per cent of global health expenditure (USD $760 billion). In China, diabetes-related costs have exceeded USD $109 billion.

Epidemiologist and public health expert, UniSA’s Dr Ming Li, says the rise of diabetes is a growing concern, especially in China where changes to the traditional Chinese diet are impacting health.

“Diet is a known and modifiable factor that contributes to the onset Type 2 diabetes, so understanding the range of dietary factors that might impact the growing prevalence of the disease is important,” Dr Li says.

“Over the past few decades China has undergone a substantial nutritional transition that’s seen many people move away from a traditional diet comprising grains and vegetables, to a more processed diet that includes greater amounts of meat, snacks and energy-dense food.

“At the same time, egg consumption has also been steadily increasing; from 1991 to 2009, the number of people eating eggs in China nearly doubled*.

“While the association between eating eggs and diabetes is often debated, this study has aimed to assess people’s long-term egg consumption of eggs and their risk of developing diabetes, as determined by fasting blood glucose.

“What we discovered was that higher long-term egg consumption (greater than 38 grams per day) increased the risk of diabetes among Chinese adults by approximately 25 per cent.

“Furthermore, adults who regularly ate a lot of eggs (over 50 grams, or equivalent to one egg, per day) had an increased risk of diabetes by 60 per cent.”

The effect was also more pronounced in women than in men.

Dr Li says that while these results suggest that higher egg consumption is positively associated with the risk of diabetes in Chinese adults, more research is needed to explore causal relationships.

“To beat diabetes, a multi-faceted approach is needed that not only encompasses research, but also a clear set of guidelines to help inform and guide the public. This study is one step towards that long-term goal.”

Notes to Editors:

  • Between the years 1991-2009, researchers found that the average daily consumption of eggs increased continuously from 16 grams in 1991-93, to 26 grams in 2000-04, and 31 grams in 2009.
  • The study population comprised 8545 adults (average age 50 years) participating in the China Health and Nutrition Survey.
  • International egg consumption across the same period was:
    • 65 g/day in Europe
    • 43 g/day in America
    • 56 g/day in Asia
    • 45 g/day in the world
    • 20 g/day in Oceania (including Australia)
    • 93 g/day in Africa.
  • Wang, Y., Li, M. and Zumin, S. (2020) ‘Higher egg consumption associated with increased risk of diabetes in Chinese adults – China Health and Nutrition Survey’ in British Journal of Nutrition. Accessed online.

Provided by University of South Australia

Food Health Star Ratings Can Improve Diets, Study Finds (Food)

More evidence has emerged that food labelling can encourage manufacturers to improve product nutrition, but University of Melbourne experts say the star labelling system must be compulsory to make a big difference.

Researchers have analysed product nutrition labels in Sydney and Auckland supermarkets to see if the Health Star Rating system made a difference to how the food industry formulates food. Image: Unsplash

A team from the University of Melbourne, the University of Auckland, and the George Institute for Global Health analysed product nutrition labels in Sydney and Auckland supermarkets to see if the Health Star Rating system (HSR) made a difference to how the food industry formulates food.

Nutritional information is mandatory on the back of packaged Australian and New Zealand foods but HSR labels, which have appeared on the front since 2014 and rate a food from 0.5 (least healthy) to five (most healthy) stars, are voluntary.

The most comprehensive study of food industry response to the HSR system, published in PLOS Medicine, has confirmed that HSR labelling causes some products to become healthier.

The Australia and New Zealand Ministerial Forum on Food Regulation introduced the voluntary front-of-pack HSR and a published HSR calculator decides how many stars a food gets. HSR labels aim to improve diets by encouraging consumers to choose healthier products and prompting manufacturers to reformulate their products to be healthier.

This study looked at the reformulation effects of HSR labels. Researchers analysed nutrition and labelling information on packaged products in four major New Zealand supermarkets annually from 2013, and Sydney supermarkets Aldi, Coles, IGA, and Woolworths from 2014.

They tracked the nutrition information of 58,905 unique packaged food products to see if HSR labelling led to nutrient composition changes. Using the HSR calculator, they also scored unlabelled products to allow control comparisons.

Products that elected to display the HSR on-pack were 6.5 and 10.7 per cent more likely to increase their HSR score by 0.5 stars than those that didn’t display the stars in Australia and New Zealand respectively.

New Zealand products with HSR showed a four per cent decline in salt content, while Australian products fell by 1.4 per cent. The HSR was associated with a 2.3 per cent decrease in sugar content in New Zealand and a statistically insignificant 1.1 per cent decline in Australia.

The healthiest products that would have scored four to five stars showed little healthier reformulation – most reformulation occurred in less healthy products with HSR labels.

In Australia, an average product with HSR that scored 0.5 to 1.5 stars lost 14kJ of energy per 100g (1.3 per cent), compared to a product that scored four to five stars which saw almost no changes in energy. Similar patterns were observed for almost all nutrients studied in both countries.

Lead author and University of Melbourne Research Fellow Dr Laxman Bablani said while the improvements sounded small, even modest changes could lead to big health impacts at a population level.

“If the labels were compulsory the impact could be much greater, as HSR adoption by the unhealthiest products was less than half that of the healthiest products,” Dr Bablani said.

In 2019, around 15 per cent of products that scored two stars had HSR labels in both countries, compared to more than 35 per cent of those that scored four stars and above. Examples of positive reformulation included:

  • A popular flavoured cracker now has six per cent less fat and roughly 10 per cent less sodium per 100g than before it adopted HSR labels in 2016. This took it from 1.5 to two stars
  • Several instant soup varieties cut sodium and energy to increase their rating from three to 3.5 stars in the year they were labelled
  • A major supermarket branded barbecue sauce cut sugar by 4.5g per 100g (9.6 per cent) in 2017 when it adopted HSR labels.

University of Auckland Professor Cliona Ni Mhurchu said the HSR could have a much bigger impact if more unhealthy products adopted it.

“Our study suggests that the total effect of HSR on supporting healthier population diets could be markedly increased if it was adopted by many more products,” Professor Ni Mhurchu said.

“In short, it suggests that making the HSR mandatory would generate substantially greater public health benefits than the current voluntary system.”

Senior author and University of Melbourne Professor Tony Blakely agreed compulsory HSR labels could improve unhealthy foods.

“There is little incentive for manufacturers to label unhealthy foods voluntarily,” Professor Blakely said.

“If it was compulsory, the quality of packaged food would improve, and consumers may possibly make better choices about healthy and unhealthy foods.”

Provided by University of Melbourne

3D-printed Glass Enhances Optical Design Flexibility (Optics / Computer)

Lawrence Livermore National Laboratory (LLNL) researchers have used multi-material 3D printing to create tailored gradient refractive index glass optics that could make for better military specialized eyewear and virtual reality goggles.

Artistic rendering of an aspirational future automated production process for custom GRIN optics, showing multi-material 3D printing of a tailored composition optic preform, conversion to glass via heat treatment, polishing and inspection of the final optics with refractive index gradients. Image by Jacob Long and Brian Chavez. ©LLNL

The new technique could achieve a variety of conventional and unconventional optical functions in a flat glass component (with no surface curvature), offering new optical design versatility in environmentally stable glass materials.

The team was able to tailor the gradient in the material compositions by actively controlling the ratio of two different glass-forming pastes or “inks” blended together inline using the direct ink writing (DIW) method of 3D printing. After the composition-varying optical preform is built using DIW, it is then densified to glass and can be finished using conventional optical polishing.

“The change in material composition leads to a change in refractive index once we convert it to glass,” said LLNL scientist Rebecca Dylla-Spears, lead author of a paper appearing today in Science Advances.

The project started in 2016 when the team began looking at ways that additive manufacturing could be used to advance optics and optical systems. Because additive manufacturing offers the ability to control both structure and composition, it provided a new path to manufacturing of gradient refractive index glass lenses.

Gradient refractive index (GRIN) optics provide an alternative to conventionally finished optics. GRIN optics contain a spatial gradient in material composition, which provides a gradient in the material refractive index — altering how light travels through the medium. A GRIN lens can have a flat surface figure yet still perform the same optical function as an equivalent conventional lens.

GRIN optics already exist in nature because of the evolution of eye lenses. Examples can be found in most species, where the change in refractive index across the eye lens is governed by the varying concentration of structural proteins.

An array of polished, 3D printed gradient refractive index lenses made of titania-doped silica glass. Grid squares are 1 millimeter on each side. ©LLNL

The ability to fully spatially control material composition and optical functionality provides new options for GRIN optic design. For example, multiple functionalities could be designed into a single optic, such as focusing combined with correction of common optical aberrations. In addition, it has been shown that the use of optics with combined surface curvature and gradients in refractive index has the potential to reduce the size and weight of optical systems.

By tailoring the index, a curved optic can be replaced with a flat surface, which could reduce finishing costs. Surface curvature also could be added to manipulate light using both bulk and surface effects.

The new technique also can save weight in optical systems. For example, it’s critical that optics used by soldiers in the field are light and portable.

“This is the first time we have combined two different glass materials by 3D printing and demonstrated their function as an optic. Although demonstrated for GRIN, the approach could be used to tailor other material or optical properties as well,” Dylla-Spears said.

Other Livermore researchers involved in the project include Timothy Yee, Koroush Sasan, Du Nguyen, Nikola Dudukovic, Jason Ortega, Michael Johnson, Oscar Herrera, Frederick Ryerson and Lana Wong. The Laboratory Directed Research and Development program funded the work.

Provided by LLNL

Meteorites Might Have Kick-started Life on Early Earth (Planetary science)

The incorporation of the biologically vital element phosphorus into material found in living species may have formed during impact from astrophysical bodies on early Earth.

Comets contain elements such as water, ammonia, methanol, carbon dioxide and phosphorous that could have supplied the raw materials, upon impact, to jump start life on early Earth. ©NASA

NASA’s Exobiology Program has awarded Lawrence Livermore National Laboratory (LLNL) senior scientist Nir Goldman a three-year grant to research meteorite impacts on Earth. Goldman is seeking to understand the role of the mineral schreibersite, (Fe,Ni)3-P, as one possible source of phosphorylated prebiotic organics.

Schreibersite is common in iron-nickel meteorites and could have contributed as much as 10 percent of the phosphorus likely present in the Earth’s early crust. In addition, the transition metal ions within the material can act as a catalyst for organic prebiotic reactivity. Of interest is its impact synthesis of phosphorylated organics on early Earth and other icy interstellar bodies.

“It’s possible that billions of years ago both prebiotic phosphorus-containing raw materials and the energy to drive chemical reactivity may have been delivered to the Earth simultaneously by the impact of these types of meteorites,” Goldman reported.

Schreibersite has been suggested as one possible source of the addition of phosphorus into prebiotic organics. Early Earth likely experienced impact events that yielded intense thermodynamic conditions that could ultimately have driven the formation of metastable organic species. This would have had high relevance during periods of heavy bombardment, where the flux of organic matter to Earth via comets and asteroids might have been as high as tens of quadrillions of kilograms per year.

“There’s reason to believe that schreibersite acted as both a source of phosphorus as well as a catalyst for essential biological phosphate production,” Goldman said.

Phosphorus is a key element in modern biochemistry. Its oxide, called phosphate ion, forms the backbone of nucleotides, the monomer units of DNA and RNA. Phosphorous’s oxide is a key component of molecules that store energy like adenosine triphosphate. It also makes up part of biological lipids. Phosphate ions can combine with calcium to form apatite, the main mineral component of bone. However, the chemical mechanisms by which phosphate could have been produced and incorporated into biological precursors on early Earth is still largely unknown.

Goldman intends to study this issue by using molecular dynamic simulations to provide an accurate description of the chemical reactivity within shock compressed schreibersite mixtures.

Previous shock synthesis studies by Goldman and others have shown that potentially life-building molecules like amino acids and peptides can be synthesized during impact events from icy materials such as comets. Similarly, meteorites are known to contain relative abundances of organic material, including alcohols, polyether and amino acids. However, the effect of phosphorus and a metal catalyst in the mix is largely unknown. The simulations in this work will focus on prebiotic synthesis from aqueous organic mixtures in the presence of schreibersite particles. The goal is to subject materials to an entire impact cycle – shock compression due to planetary impact, followed by expansion and then cooling and equilibration.

“Our goals are to create a more complete understanding of the possible elementary phosphate chemistry steps in prebiotic synthesis over the wide range of pressure-temperature conditions that likely existed on the early planet,” Goldman said.

Provided by Lawrence Livermore National Laboratory

Bodies Of Man And His Slave Unearthed From Ashes at Pompeii (Archeology)

Skeletal remains of what are believed to have been a rich man and his male slave attempting to escape death from the eruption of Mount Vesuvius nearly 2,000 years ago have been discovered in Pompeii, officials at the archaeological park in Italy said Saturday.

The casts of what are believed to have been a rich man and his male slave fleeing the volcanic eruption of Vesuvius nearly 2,000 years ago. (AP)

Parts of the skulls and bones of the two men were found during excavation of the ruins from what was once an elegant villa with a panoramic view of the Mediterranean Sea on the outskirts of the ancient Roman city destroyed by the volcano eruption in 79 A.D. It’s the same area where a stable with the remains of three harnessed horses were excavated in 2017.

Pompeii officials said the men apparently escaped the initial fall of ash from Mount Vesuvius then succumbed to a powerful volcanic blast that took place the next morning. The later blast “apparently invaded the area from many points, surrounding and burying the victims in ash,” Pompeii officials said in a statement.

A detail of the casts of one of two bodies. One is believed to have been a rich man aged in his 30s or 40s and the other his male slave. (AP)

The remains of the two victims, lying next to each other on their backs, were found in a layer of gray ash at least 2 meters (6.5 feet) deep, they said.

As has been done when other remains have been discovered at the Pompeii site, archaeologists poured liquid chalk poured into the cavities, or void, left by the decaying bodies in the ash and pumice that rained down from the volcano near modern-day Naples and demolished the upper levels of the villa.

The technique, pioneered in the 1800s, gives the image not only of the shape and position of the victims in the throes of death, but makes the remains “seem like statues,” said Massimo Osanna, an archaeologist who is director general of the archaeological park operated under the jurisdiction of the Italian Culture Ministry.

It’s the same area where a stable with the remains of three harnessed horses were excavated in 2017. (AP)

Judging by cranial bones and teeth, one of the men was young, likely aged 18 to 25, with a spinal column with compressed discs. That finding led archaeologists to hypothesize that he was a young man who did manual labor, like that of a slave.

The other man had a robust bone structure, especially in his chest area, and died with his hands on his chest and his legs bent and spread apart. He was estimated to have been 30- to 40-years-old, Pompeii officials said. Fragments of white paint were found near the man’s face, probably remnants of a collapsed upper wall, the officials said.

Both skeletons were found in a side room along an underground corridor, or passageway, known in ancient Roman times as a cryptoporticus, which led to to the upper level of the villa.

“The victims were probably looking for shelter in the cryptoporticus, in this underground space, where they thought they were better protected,” said Osanna.

Instead, on the morning of Oct. 25, 79 A.D., a “blazing cloud (of volcanic material) arrived in Pompeii and…killed anyone it encountered on its way,” Osanna said.

Based on the impression of fabric folds left in the ash layer, it appeared the younger man was wearing a short, pleated tunic, possibly of wool. The older victim, in addition to wearing a tunic, appeared to have had a mantle over his left shoulder.

Mount Vesuvius remans an active volcano. While excavations continue at the site near Naples, tourists are currently barred from the archaeological park under national anti-COVID-19 measures.

Provided by 9News