The Icelandic walrus lived on the island of Iceland for thousands of years but died out shortly after the arrival of the first Norwegians around 870 AD. Researchers believe it was no accident: these animals were hunted and above all the ivory of their horns was marketed. Now a new study, published in Molecular Biology and Evolution, provides us with new information about it.
Icelandic, Danish and Dutch researchers have in fact analyzed the ancient DNA of some collections of bones preserved in the museum of Icelandic natural history and have performed carbon 14 dating of some remains of walruses. The study confirms first of all that this animal lived in Iceland for thousands of years and disappeared with the arrival of the first groups of Norwegians.
The researchers also compared the DNA of these walruses with contemporary walruses and confirmed that it was a single genetic progeny distinct from all other populations of both contemporary and historical walruses. According to Morten Tange Olsen, a researcher at the University of Copenhagen and one of the authors of the study, this research shows one of the first examples of extinction of a marine animal following the arrival of groups of human beings and following the exploitation carried out by the latter.
The ivory of walruses was in fact considered a luxury commodity and was in great demand both during the Viking era and during the Middle Ages in the rest of Europe. There are numerous documents describing carefully decorated walrus tusks that were marketed from Europe to the Middle East and on to India.
“More than 1000 years ago, commercial hunting, economic incentives and commercial networks were of sufficient size and intensity to cause significant and irreversible ecological impacts on the marine environment, potentially exacerbated by a hot climate and volcanism,” says Xénia Keighley, researcher at the GLOBE Institute in Copenhagen and the Arctic Centre in Groningen and principal author of the research.
A new study published in PLOS ONE, by researchers at Monash University, Australia, focused on marsupial palorchestides. It is an extinct group of Australian megafauna that has lived for most of the last 25 million years, mostly in eastern Australia.
They had large sizes, skulls similar to tapirs and large claws. The study focused in particular on the morphology of the limbs. After examining 60 fossils of marsupials of various ages, the researchers confirmed that the marsupials have undergone several evolutionary changes over millions of years.
The last specimens lived could have weighed more than 500 pounds. This weight was held up by very muscular limbs, especially the anterior ones, which, among other things, had also adapted to scrape leaves and branches. The forelimbs, in fact, had elbow joints fixed at an angle of about 100°: in this way, the legs, permanently bent, served as tools for collecting food.
“This study allowed us for the first time to appreciate how enormous these mega-marsupial palorquestids were, also providing the first complete view of a strange anatomy of the limbs unprecedented in the world of mammals. This research reveals even more the diversity of the great unique marsupials that once roamed Australia,” the authors of the study state in the press release.
A study conducted by researchers from the University of Heidelberg and the Curt Engelhorn Center for Archaeometry in Mannheim analyzed various findings made of tin dating back to the second millennium BC found at various archaeological sites in Israel, Greece and Turkey.
Following the analysis, the researchers, who published a study on PLoS ONE, were convinced that the same pond did not come, in the form of ingots, from the areas of Central Asia, as had been assumed previously in other analyses, but from deposits located in Europe.
This discovery shows that even during this era, the Bronze Age, there were fairly large trade routes between Europe and the eastern Mediterranean and that several raw materials, very important and appreciated, such as tin, amber, glass and copper, were among the first to be marketed on these routes.
“The origin of the pond has long been an enigma in archaeological research,” says Ernst Pernicka, one of the authors of the study which also explains that all the objects made with the pond found in the region of the eastern Mediterranean can not come from this same region because in this area there were virtually no deposits.
This means that this raw material was exchanged, in the form of ingots, on fairly extensive trade routes related not only to Asia but also to Europe. Through the analysis of lead and tin isotopes, researchers found that the tin in the findings they analyzed corresponds to the tin in the regions of Cornwall and Devon, Great Britain.
According to a new study conducted by researchers at the University of Toledo, United States, people who have a history of liver disease are more prone to problems that can cause toxic algae. Microbes present in toxic algae during flowering can produce a class of toxins called microcystins.
The latter can influence, more strongly than previously thought according to the researchers behind this study, people with non-alcoholic fatty liver disease (NAFLD). According to the press release presenting the research published in the journal Toxins, this toxin may, in fact, increase the effects of this disease even when it is present at low levels.
According to David Kennedy, professor of medicine at the American university and lead author of the study, this research suggests “that there are some groups of people who need to pay more attention and may be more sensitive to microcystin toxins. We may need to explore special preventive guidelines for those people in terms of how much microcystine they are exposed through drinking water or other means.”
The researchers carried out experiments on mice testing the effects of microcysstin-LR (MC-LR) on healthy mice. The latter were exposed to microcystin every 48 hours for four weeks; researchers noted early mortality and significant increases in alkaline phosphatase levels and histopathological markers of liver damage as well as overregulation of genes associated with hepatotoxicity, necrosis, nongenotoxic hepatocarcinogenicity and oxidative stress response, as reported in the study abstract (see second link below).
Some rare deaths related to the microcystin produced by toxic algae have been reported for example in a group of patients suffering from renal dialysis in Brazil while several cases of dogs dying from exposure to so-called “blue-green algae” (cyanobacteria) have been reported in different parts, especially in the United States.
Some people have theorized that cutting fossil fuel emissions too aggressively and too quickly can have an unwanted effect and even cause the same temperature to rise in the short term. Now a new study by Duke University shows that this is an implausible scenario and therefore not to be taken into consideration.
As specified in the press release Drew Shindell, professor of Earth Sciences at the Nicholas School of the Environment and one of the authors of the study, in any plausible scenario with reductions in emissions from fossil fuels among those that can be assumed, there are no significant peaks in warming or other harmful consequences for the climate.
All these scenarios show decreases in heating rates within at least two decades of the start of the phase-out. The researchers analyzed 42 plausible scenarios with a more or less gradual phase-out of fossil fuel use.
The only scenario in which there is a significant warming peak is an implausible one, i.e. one in which global emissions are stopped instantly or very quickly. This is an implausible scenario, as Shindell himself points out, as it will take decades to switch to clean energy.
The idea is that the earth’s atmosphere can in a short time free itself from the so-called “aerosol”, a compound produced by the consumption of fossil fuel that partly obscures the Sun, while greenhouse gases, such as carbon dioxide, would persist and this could lead to a short-term increase in atmospheric warming (someone has assumed about half a degree Celsius). According to Smith, these are “unfounded fears.” The same researcher adds that “any increase in the rate or level of short-term warming will be rather small compared to what we would see if we allowed emissions to remain at current levels.”
“What this work shows is that it is wrong to think that the transition to clean energy also has great environmental risks. Instead, it provides huge public health benefits and mitigates climate change,” says Shindell.
The study was published in Nature.
A study has taken into account the relationship between paracetamol in pregnancy and the possible consequences on the child. The research, published in Paediatric and Perinatal Epidemiology, examined in particular the possible correlations between the intake of paracetamol in the mid-pregnancy period and the behavior of children between six months and 17 years of age.
Paracetamol is a substance that is commonly used to calm pain during pregnancy. Researchers at the University of Bristol examined a cohort study containing data from 14,000 children. 43% of their mothers reported having taken paracetamol at about seven months of pregnancy at various levels.
Researchers also analyzed data on children’s responses to various intelligence and memory tests as well as other data on temperament and behavior. They then found an association between paracetamol intake and children’s hyperactivity and attention problems, as well as with other difficult behaviors.
However, these problems seemed to be no longer present when the children reached the end of primary school. They also found that males seemed more sensitive to these effects than females.
Jean Golding, one of the researchers involved in the study, comments on these findings in a press release published on the University of Bristol website: “Our findings are in addition to a series of findings concerning the evidence of possible adverse effects of paracetamol intake during pregnancy, such as as asthma problems or behavior in the offspring. It reinforces the advice that women should be cautious when taking medication during pregnancy and that they should seek medical advice where necessary.”
However, the same researcher admits that these findings need further investigation with other studies.
After analyzing Culicoides impunctatus, also known as “midge,” generally widespread from late spring until summer in Scotland and Wales (but can be found in all northern regions of the Palearctic), a group of researchers discovered several new viruses.
Among them, the researchers have classified an alphavirus and a chuvirus, viruses that, at least at the moment, are not considered a threat to humans. These small flying insects are in fact known because they also sting humans but all the blood they need is taken mostly from mammals such as cattle, sheep, deer, or birds, such as herons.
In rare cases, they have been found to carry arboviruses, which were found to be responsible for an emergency following the spread of the Schmallenberg virus (SBV) in Europe in 2011.
In relation to the study modalities used, the principal author of the research, Sejal Modha, states in the press release: “The technology we have used has allowed us to examine the viruses carried by midges in a way that cannot be done in the laboratory, expanding our knowledge of insect viruses in a way that could be very useful in the future.”
The other author of the study, Joseph Hughes, points out how much this discovery represents only the small tip of a huge iceberg about the millions of species of viruses that exist. Even if we consider those carried by insects, with 5.5 million species of insects classified to date, there are probably tens, if not hundreds, of millions of different species of viruses never detected by humans.
A group of scientists discovered that four substances found in Mimosa caesalpiniifolia, a plant with white flowers of the fabaceae endemic to Brazil, can be very effective against lily of the valley and candida, even more than fluconazole, so much so that the researchers themselves involved are already developing an ointment.
Lily of the Valley and candidiasis are two diseases caused by fungi of the genus Candida. If they affect people with a low level of immunity, they can also be quite serious, which is why they can be a danger in hospitals. To combat these diseases, an antifungal drug known as fluconazole is usually used, which is sufficient in most cases.
However, some varieties of fungi are becoming increasingly resistant to this type of drug. According to FAPESP researchers, the substances that they have identified in Mimosa caesalpiniifolia may be the basis for a new treatment that could decrease the side effects of antimicrobial agents that are traditionally used to combat this infection.
In addition, according to Wagner Vilegas, principal author of the study, the level of resistance of fungi could also be reduced by such a treatment but further research is needed.
A new study by researchers from the State University of Pennsylvania finds a positive aspect in eating cheese. According to the researchers, the antioxidants that this food contains can protect blood vessels from damage that can be caused by excessive use of salt in the diet.
The study was conducted by Billie Alba while she finished her PhD at that university. The researcher found in her randomized study that adults who showed a blood vessel dysfunction due to a diet rich in sodium but at the same time consumed at least four servings of cheese a day, could compensate for this damage.
The study was conducted on 11 adults who followed four different diets for eight days at a time: a diet low in sodium and without cheese, a diet low in sodium and rich in cheese, a diet rich in sodium and without cheese and a diet rich in sodium and rich in cheese. At the end of each diet week, participants returned to the laboratory for the test, which included an examination of the blood vessels.
The same researcher admits that it is difficult to push people to reduce salt in the diet and that this new discovery, perhaps, will help to counteract the damage that this ingredient can bring to the body, especially to the cardiovascular system.
Lacy Alexander, a professor of kinesiology at Penn State, also took part in the study and said in the press release: “We wanted to examine these connections more closely and explore some of the precise mechanisms by which cheese, a dairy product, can affect heart health.”
The solution to permanently beat infections such as the cold, caused by the rhinovirus, could be found within our own cells according to a new study conducted by researchers at the University of California in San Francisco.
According to experiments conducted by researchers on human cell cultures and mice, temporarily disabling a particular protein can prevent many species of enteroviruses, including rhinoviruses, from replicating within the cells. All enteroviruses seem to need this particular protein to replicate.
To understand what proteins were vital for enteroviruses, researchers first generated a culture with human cells and had them infected by rhinovirus RV-C15, which causes asthma in children, and EV-C68, which causes acute flaccid myelitis. They then used genetic editing to randomly disable individual genes in each of the cells and found that a single gene produces an enzyme called SETD3 that was clearly essential to the success of the infection.
To prove it, they created a new culture of human cells without SETD3 and tried to infect them with various enteroviruses, including two varieties of coxsackievirus, a virus that can cause myocarditis. None of these viruses could replicate in cells that no longer produced the enzyme SETD3.
Performing the same experiment but in vivo on mice, the latter, completely missing SETD3, grew up to adulthood in good health and were also fertile. The same researchers also discovered that enteroviruses do not seem to make any particular use of the enzyme SETD3; more than anything else they move around this protein that, in yet unknown ways, is almost necessary for their replication.
This latest discovery gives researchers hope that they can develop a drug with an antiviral activity similar to that of the absence of SETD3 without disturbing the latter in the cells.