More extreme El Niño, La Niña events could drive global warming, study finds INQUIRER.net
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‘Cold-adapted’ dinosaurs survived mass extinction event to achieve dominance, study finds
A new study has offered what it says is the first physical evidence showing dinosaurs from the Triassic period regularly endured freezing conditions, allowing them to survive and eventually supersede other species on the planet.
The study, published in the journal Science Advances on July 1, looks at the circumstances surrounding the Triassic-Jurassic Extinction 202 million years ago, which killed off a number of large reptiles and led to the eventual takeover of dinosaurs.
During the extinction event, researchers say cold snaps killed off many cold-blooded reptiles.
Through studying footprints and rock fragments in a remote desert of the Junggar Basin in northwest China, the researchers say Triassic dinosaurs, a relatively minor group populating Earth’s polar regions, survived the “evolutionary bottleneck and spread out.”
“Dinosaurs were there during the Triassic under the radar all the time,” Paul Olsen, a geologist at Columbia University’s Lamont-Doherty Earth Observatory and lead author of the study, said in a statement.
“The key to their eventual dominance was very simple. They were fundamentally cold-adapted animals. When it got cold everywhere, they were ready, and other animals weren’t.”
Dinosaurs are thought to have first appeared about 231 million years ago during the Triassic period in temperate southern latitudes, the researchers say.
At the time, most of Earth’s land was joined together as one giant continent known as Pangaea.
Dinosaurs made it to the far north about 214 million years ago and until the mass extinction, reptiles dominated the planet’s tropical and subtropical regions.
While atmospheric concentrations of carbon dioxide then were at or above 2,000 parts per million or five times today’s levels resulting in “intense” temperatures, the researchers say climate models suggest higher latitudes did experience seasonal temperature declines and would have received little sunlight much of the year.
By the end of the Triassic period, the researchers say massive volcanic eruptions potentially lasting hundreds of years killed more than three-quarters of all terrestrial and marine life on the planet.
The eruptions also would have caused carbon dioxide levels in the atmosphere to rise, creating deadly temperature spikes and making ocean waters too acidic for many lifeforms.
But the researchers say the eruptions also would have released sulfur aerosols, capable of deflecting sunlight and causing repeated “global volcanic winters” lasting a decade and possibly longer.
Not only were Triassic dinosaurs able to survive under these conditions, the researchers say evidence has shown many if not all non-avian dinosaurs also had primitive feathers that would have been used mainly as insulation. Many dinosaurs also are believed to have been warm blooded and possessed high metabolisms.
“There is a stereotype that dinosaurs always lived in lush tropical jungles, but this new research shows that the higher latitudes would have been freezing and even covered in ice during parts of the year,” Stephen Brusatte, a professor of paleontology and evolution at the University of Edinburgh, said.
“Dinosaurs living at high latitudes just so happened to already have winter coats [while] many of their Triassic competitors died out.”
As for the physical evidence supporting their study, the researchers looked at fine-grained sandstone and siltstone formations left behind in the sediments of shallow ancient lake bottoms in the Junggar Basin, formed 206 million years ago during the late Triassic. At the time, the basin would have been located above the Arctic Circle.
Footprints show dinosaurs were present along the shorelines, while pebbles about 1.5 centimetres wide, found far from any apparent shoreline, offered evidence of “ice-rafted debris,” they say.
Ice-rafted debris forms when ice builds against a coastal landmass and takes in bits of underlying rock, the researchers say.
The ice eventually detaches and drifts away. As it melts, the rocks fall off and mix in with the sediment.
The researchers say the pebbles were likely picked up during the winter when lake waters froze and floated away as the weather warmed.
“This shows that these areas froze regularly, and the dinosaurs did just fine,” study co-author Dennis Kent, a geologist at Lamont-Doherty, said.
The researchers say more work is needed to find fossils in former polar areas, such as the Junggar Basin.
Climate change role clear in many extreme events but social factors also key, study finds
Climate change is to blame for the majority of the heatwaves being recorded around the planet but the relation to other extreme events impacts on society is less clear, according to a study.
“I think on the one hand we overestimate climate change because it’s now quite common that every time an extreme event happens, there is a big assumption that climate change is playing a big role, which is not always the case,” said Friederike Otto, a climate change and environment professor at the Grantham Institute at Imperial College London, who was one of the lead authors of the research.
“But on the other hand, we really underestimate those events where climate change does play a role in what the costs are, especially the non-economic costs of extreme weather events to our societies.”
In the study published in the journal IOP Publishing, Otto’s team used “attribution science” to pore over available international data, literature and climate models – as well as the latest Intergovernmental Panel on Climate Change reports – and calculate how human-induced climate change is affecting the impact of five types of extreme weather events: heatwaves, heavy rainfall, drought, wildfires and tropical cyclones.
They say that in the case of heatwaves, the role of climate change is unequivocal, and that the average and extreme heat levels in every continent across the globe are increasing specifically because of human-caused climate change.
A heatwave with a one in 50 chance of happening in pre-industrial times is now almost five times more likely to happen and will be 1.2C hotter, according to an IPCC report. In the past 20 years there have been 157,000 deaths from 34 heatwaves, according to data from the EMDAT disaster database. Yet the impact of human-induced climate change on heatwaves and the repercussions are still largely underestimated.
“One big reason why we underestimate heatwaves so dramatically is because no one’s dropping dead on the street during a heatwave, or at least very few people do,” Otto said.
Most people died from pre-existing conditions suddenly becoming acute, Otto said, and this often did not show up in data. Wildfires were also one of the big climate impacts not talked about enough, Otto said.
For other events such as droughts, floods and tropical cyclones, there is a more nuanced link to climate change. For example, there are some regions of the world where droughts are becoming worse because of human-caused climate change, such as southern Africa, Otto notes, while in other droughts the climate change signal is either not there or very small.
“By focusing too much on climate change, it really takes the responsibility, but also the agency, away to address these local drivers of disasters such as high poverty rates, missing infrastructure, investment, missing healthcare system … all these aspects of exposure and vulnerability that make every drought a catastrophe,” Otto said.
“That will not go away even if we stop burning fossil fuels today. I think that that is why the overestimation of climate change – by basically blaming this all on climate change – is not very helpful for actually dealing [with] and for actually improving resilience to these threats.”
Much of the problem in figuring out exactly to what extent climate change was responsible for the impact of extreme weather events, Otto said, lay in the lack of reliable data around the globe.
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There is not enough information coming from lower- and middle-income countries, although these are the places more likely to be at risk of the repercussions of human-induced climate change.
Already there’s been substantial scientific progress in the last few years in attributing extreme events and their consequences to human-made climate change, said Frances Moore, a professor of environmental economics at the University of California, Davis, who was not involved in the study.
“But an important caveat is that the consequences of climate change do not only operate through extremes,” said Moore. Changes in “average conditions” can also have large consequences for mortality, agriculture, worker productivity and safety. “It may well be that the aggregate consequences of these changing, ‘non-extreme’ conditions constitute a large fraction of total climate change impacts.”
Otto called for a broader definition of what was considered as “risk” in climate change modelling, rather than simply sticking to hazards and impact. Other factors such as the effects that extreme weather has on individuals, labour productivity, infrastructure, agricultural systems and property should be taken into account, he said.
“We started at ‘no one was ever talking about climate change’ and now we’ve sort of moved over to ‘blaming a lot of things on climate change’,” Otto said. “[This is] a plea towards realising that reality is somewhat messy, in the middle, and that we need to disentangle these drivers better in order to actually prioritise our adaptation and resilience building to really address climate change properly.”
Analysis finds little proof that testosterone treatment increases the risk of cardiovascular events
Testosterone replacement therapy appears safe in the short-to-medium term to treat a condition caused by deficiency of the male sex hormone, according to the most comprehensive analysis of the treatment to date, published in The Lancet Healthy Longevity journal.
The findings suggest that men given testosterone to treat hypogonadism are at no greater risk of heart attack, stroke, and other cardiovascular events in the short-to-medium term than men who do not receive testosterone treatment.
Testosterone replacement therapy is the standard treatment for hypogonadism, which can cause sexual dysfunction, weakening of bones and muscles, and reduced quality of life. Risk factors for the condition include aging (as testosterone levels decline with age), obesity (BMI of 30 kg/m2 or above), and diabetes.
Despite being widely used, the cardiovascular safety of testosterone treatment has until now remained unclear due to inconsistent findings. This is because most previous clinical studies have relied on aggregate data, rather than individual participant data and have not published details of individual adverse events.
Prescribing of testosterone for hypogonadism is increasing globally, but conflicting messages about its safety may have led to many patients not receiving the treatment. Ongoing studies should help to determine the longer-term safety of testosterone but, in the meantime, our results provide much-needed reassurance about its short-to-medium term safety. Our findings could have important implications for the treatment of men with hypogonadism worldwide.”
Jemma Hudson, Study Lead Author, University of Aberdeen
The authors conducted a systematic review identifying 35 eligible clinical trials published since 1992, of which 17 provided individual participant data. A blinded analysis by two independent clinicians enabled the classification of every cardiovascular event, allowing for a more robust analysis of the cardiovascular safety of testosterone treatment.
A meta-analysis using individual participant data from 17 studies and a further meta-analysis integrating these data with the aggregate data provided by the 18 trials that did not provide individual participant data were performed.
Among the 17 trials with individual patient data, 1,750 participants received testosterone and 1,681 were given a placebo. The average length of testosterone treatment was 9.5 months. The average age of participants was 65 years, and most were white and did not smoke. Participants’ average BMI was 30 kg/m2, which is considered obese.
A meta-analysis showed there were 120/1,601 (7.5%) cardiovascular events in the testosterone group and 110/1,519 (7.2%) in the placebo group across 13 trials that provided this information. Patient age, smoking or diabetes status did not affect cardiovascular risk. Similarly, there was no significant difference in mortality rate between the testosterone group (6/1,621 deaths, 0.4%) and the placebo group (12/1,537 deaths, 0.8%) across the 14 trials that provided individual patient data on mortality, but only limited data were available.
The researchers also found that testosterone significantly reduced serum total cholesterol, high-density lipoprotein (HDL), and triglycerides compared with placebo. However, there were no significant differences in serum low-density lipoprotein (LDL), blood pressure, glycaemic parameters, diabetes incidence, and prostate adverse outcomes between the testosterone and placebo groups.
The meta-analysis that integrated individual participant data with aggregate data showed similar results.
The authors acknowledge some limitations to their study. There was little available data evaluating the cardiovascular safety of testosterone treatment beyond 12 months, and the very small number of deaths recorded during testosterone trials hampered the authors’ ability to analyze why they occurred.
However, the longer-term safety of testosterone treatment is currently being investigated in another clinical trial. While the meta-analysis of aggregate data showed similar results to the one involving individual patient data only, it cannot be ruled out with certainty that a high number of unreported cardiovascular events in the trials that did not provide individual participant data could alter the current conclusions.
Source:
Journal reference:
Hudson, J., et al. (2022) Adverse cardiovascular events and mortality in men during testosterone treatment: an individual patient and aggregate data meta-analysis. The Lancet Healthy Longevity. doi.org/10.1016/S2666-7568(22)00096-4
Clopidogrel monotherapy linked with reduced risk of net adverse clinical events, study finds
Results from a real-world study investigating safety and effectiveness of clopidogrel versus aspirin monotherapy beyond 12 months after PCI in high-risk patients during the chronic maintenance period. This study found that clopidogrel monotherapy was associated with reduced risk of net adverse clinical events (NACE; all-cause death, MI, stent thrombosis, stroke, or BARC type 2, 3, or 5 bleeding) and MACCE (death, MI, stent thrombosis, stroke), and a numerical decrease in major or clinically relevant nonmajor bleeding (BARC type 2, 3, or 5 bleeding), compared with aspirin monotherapy. The findings were presented today as late-breaking clinical research at the Society for Cardiovascular Angiography & Interventions (SCAI) 2022 Scientific Sessions.
P2Y12 inhibitor monotherapy reduces bleeding risk without increasing the risk of ischemic events compared with dual antiplatelet therapy (DAPT), especially in the first 12 months following percutaneous coronary intervention (PCI). Recent research showed that among patients who were event free for six to 18 months post-PCI and successfully received the intended duration of DAPT, clopidogrel monotherapy was superior compared with aspirin monotherapy in terms of NACE. However, optimal antiplatelet monotherapy during the chronic maintenance period beyond 12 months after PCI with drug-eluting stents in high-risk patients in real-world settings is previously unknown.
In total, 8,377 consecutive patients at high risk for both bleeding and thrombosis were identified from the prospective Fuwai PCI Registry if they satisfied one clinical and one angiographic criterion. Patients who received antiplatelet (aspirin or clopidogrel) monotherapy longer than 12 months and were free from ischemic and bleeding events at 12-month post-PCI without extended duration of DAPT were included. The primary endpoint was net adverse clinical events (NACE) from 12 to 30 months. The key secondary endpoints were major adverse cardiac or cerebral events (MACCE) and major or clinically relevant nonmajor bleeding (BARC type 2, 3 or 5).
“These findings show for the first time clopidogrel monotherapy is associated with reduced risk of long-term NACE and MACCE,” said Hao-Yu Wang, Cardiometabolic Medicine Center, Coronary Heart Disease Center, Department of Cardiology, Fuwai Hospital, State Key Laboratory of Cardiovascular Disease, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China. “Our results may have important practical implications for determining the optimal treatment for patients requiring a single antiplatelet drug, either aspirin or clopidogrel, for secondary prevention of ischemic events in high-risk PCI population.”
Of 7,392 high-risk patients that were event-free after the first year and adherent to DAPT, 5,664 patients who received antiplatelet monotherapy (clopidogrel monotherapy: n=1,974 and aspirin monotherapy: n=3690) were included in the present analysis. Researchers found that between 12 and 30 months, the net adverse clinical events were lower with clopidogrel monotherapy compared to aspirin monotherapy (Kaplan-Meier estimate: 2.5% vs. 5.0%; adjusted HR:0.566, 95% CI: 0.403-0.795). Clopidogrel monotherapy was associated with lower risk for MACCE (Kaplan-Meier estimate: 1.0% vs. 3.1%, log-rank p = 0.001 ), as well as lower incidence rates of all-cause death, MI, and stroke. The difference in risk between the groups was statistically similar for major or clinically relevant nonmajor bleeding (Kaplan-Meier estimate: 1.5% vs. 2.1%, log-rank p = 0.199).
Researchers recommended that their findings should be further investigated through a randomized clinical trial.
Female Patients More Likely Than Males to Experience Severe Adverse Events During Cancer Treatment, Study Finds
Women are known to experience more adverse events with chemotherapy, but a recent study found an increased risk across therapy types, especially immunotherapy.
Women receiving chemotherapy are likely to have more adverse events (AEs) than men undergoing the treatment, but very little research has assessed the differences between men and women’s experiences with immunotherapy or targeted therapy. A recent study explored the role of patient sex in symptomatic and objective AEs with cytotoxic, immune, and targeted therapies for cancer.
The study, published in the Journal of Clinical Oncology, used SWOG Cancer Research Network phase 2 and 3 clinical trial data from trials between 1980 and 2019. Sex-specific cancers were excluded from the analysis.
In total, 13 symptomatic AEs and 14 objective and measurable AEs were analyzed. Symptomatic AEs included those in the Patient-Reported Outcome Common Terminology Criteria for Adverse Events given past evidence that clinician reports may under-report symptomatic AEs. Objective AEs were laboratory-based or measurable and were also categorized as either hematologic or nonhematologic.
Overall, 23,296 patients including 8838 women (37.9%) from 202 trials were included in the study. Of the patients included, 17,417 received chemotherapy, 2319 received immunotherapy, and 3560 received targeted therapy. Collectively, patients experienced 274,688 AEs, with 15,051 (64.6%) experiencing AEs of grade 3 or higher. Chemotherapy was especially prevalent in trials between 1989 and 1999. Immunotherapy and targeted therapies were more common from 2010 to 2019.
“It has been understood that women have more toxicity from chemotherapy than men, but almost no research has aimed to understand whether that pattern held for novel treatments like immunotherapy or targeted therapies,” study author Joseph Unger, PhD, associate professor, biostatistician, and health sciences researcher at Fred Hutchinson Cancer Center, said in a statement. “We found similar large differences, especially for immune treatments.”
While 64.6% of all patients experienced 1 or more severe AE, women had a 34% greater risk of severe toxicity than men (odds ratio [OR], 1.34; 95% CI, 1.27 to 1.42; P < .001). Women were at an increased risk across treatment types, especially immunotherapy (OR, 1.49; 95% CI, 1.24 to 1.78; P < .001).
Women were at a 33.3% greater risk of experiencing symptomatic AEs (OR, 1.33; 95% CI, 1.26 to 1.41; P < .001) compared with men (27.9%). They also had an increased risk of hematologic AEs compared with men (45.2% vs. 39.1%) and objective nonhematologic AEs (30.9% vs 29.0%). Women treated with immunotherapy were at an especially higher risk of severe symptomatic and hematologic AEs than men who received immunotherapy (33.7% vs 25.4%). Severe objective, nonhematologic AEs occurred at similar rates in men and women across treatment types.
These findings suggest that, in addition to the typical patient and tumor characteristics considered in cancer treatment decisions, patient sex may be a key factor in maximizing treatment efficacy while limiting toxicity. This is especially relevant with immunotherapy, during which women were at the greatest risk for severe AEs in this study.
The authors presented several possible explanations for the sex-related differences in AEs. They could be related to body size differences and relative dosing, differences in medication adherence for oral therapies, bias in the interpretation and reporting of AEs, or different reporting habits in men and women. However, the authors noted that objective hematologic AEs were also more common in women in these trials.
One study limitation is the population, which is limited to clinical trials and therefore likely includes younger, healthier patients than the general patient population, study authors said. The study also only included the worst toxicity grade in each category, so there was no observation of toxicity patterns over time.
Despite limitations, these findings suggest that sex could be an important factor in individualizing cancer treatment and maximizing efficacy.
“If confirmed, our findings suggest that underlying mechanisms may result in generalized worse toxicity outcomes for women, with or without corresponding survival improvements or detriments,” the authors wrote. “Therefore, more awareness of symptom differences or reporting differences in women versus men is needed.”
Reference
Unger JM, Vaidya R, Albain KS, et al. Sex differences in risk of severe adverse events in patients receiving immunotherapy, targeted therapy, or chemotherapy in cancer clinical trials. J Clin Oncol. Published online February 4, 2022. doi:10.1200/JCO.21.02377
Cities hosting major sporting events lack communications strategy, survey finds
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