Tyler O'Neal, Staff Editor GOVERNMENT

Computational study of famous fossil reveals evolution of locomotion in 'ruling reptiles'

New modeling of ancient fossil movement reveals an important step in the evolution of posture in the ancestors of dinosaurs and crocodiles

Scientists from the University of Bristol and the Royal Veterinary College (RVC) used three-dimensional computer modeling to investigate the hindlimb of Euparkeria capensis-a small reptile that lived in the Triassic Period 245 million years ago-and inferred that it had a "mosaic" of functions in locomotion.

The study, which was published today in Scientific Reports, was led by researcher Oliver Demuth, joined by Professors Emily Rayfield (Bristol) and John Hutchinson (RVC). Their new micro-computed tomography scans of multiple specimens revealed unprecedented information about the previously hidden shape of the hip bones and structure of the foot and ankle joint. CAPTION This projection of the hip bone above the hip joint is called

Euparkeria has been known from numerous fossil specimens since the early 1900s and was found to be a close relative of the last common ancestor of both crocodiles and birds. While birds and crocodiles show different locomotion strategies, two-legged birds with an upright (erect) posture, shared with two and four-legged dinosaurs, and crocodiles having a four-legged (quadrupedal) sprawling posture, their ancestor once shared a common mode of locomotion and Euparkeria can provide vital insight into how these differences came to be.

The authors' new reconstruction of the hip structure showed that Euparkeria had a distinctive bony rim on the pelvis, called a supra-acetabular rim, covering the top of the hip joint. This feature was previously known only from later archosaurs on the line to crocodiles and often was used to infer a more erect posture for these animals; reversed in crocodiles as they became more amphibious. The hooded rim allowed the pelvis to cover the top of the thigh bone and support the body with the limbs in a columnar arrangement; hence this type of joint is called 'pillar-erect'. Euparkeria is so far the earliest reptile with this structure preserved. Could it, therefore, have assumed a more erect, rather than more sprawling, posture as well?

To test how the hindlimb could or could not have moved in life, the team estimated how far the thigh bone could have rotated until it collided with the hip bones, and their models addressed how the ankle joint could have been posed, too. The supercomputer simulations suggested that while the thigh bone could have been held in an erect posture, the foot could not have been placed steadily on the ground due to the way the foot rotates around the ankle joint, implying a more sprawling posture. However, the bony rim covering the hip joint restricted the movement of the thigh bone in a way that is unknown in any living animal capable of a more sprawling gait, hinting at a more upright posture.

The team's simulations thus revealed seemingly contradictory patterns in the hip and ankle joint. While Euparkeria is so far the earliest reptile with this peculiar hip structure, an ankle joint allowing a more erect posture appeared later on in Triassic archosaurs. Dr. John Hutchinson, Professor of Evolutionary Biomechanics at the RVC, commented:

"The mosaic of structures present in Euparkeria, then, can be seen as a central stepping-stone in the evolution of locomotion in archosaurs."

First author Oliver Demuth, a research technician at the RVC and former Masters student at the University of Bristol commented:

"The hip structure of Euparkeria was extremely surprising, especially as it functionally contradicts the ankle joint. Previously it was thought that both were linked and evolved synchronously. However, we were able to demonstrate that these traits were in fact decoupled and evolved in a step-wise fashion."

Dr. Emily Rayfield, Professor of Palaeobiology at the University of Bristol commented:

"This approach is exciting because Using CT scan datasets and computer models of how the bones and joints fitted together have allowed us to test long-standing ideas of how these ancient animals moved and how the limbs of the earliest ancestors of birds, crocodiles, and dinosaurs may have evolved"

Warwick researchers use supercomputer simulations to investigate personalised mechanical ventilation of COVID-19 patients

Tyler O'Neal, Staff Editor GOVERNMENT

Initial clinical guidelines for mechanical ventilation of COVID-19 patients suggested following standard approaches used in the treatment of acute respiratory distress syndrome (ARDS), which is characterized by rapid onset of widespread inflammation in the lungs.

However, emerging clinical experience in China, Italy, the UK, and elsewhere suggests that some patients with COVID-19 pneumonia present with a particular form of the syndrome, characterized by severe hypoxemia (inadequate oxygen in the blood) with relatively well-preserved lung mechanics. The pathophysiological basis for this particular characteristic of COVID-19 ARDS remains unclear, and is currently the subject of intense debate among clinicians, since it may have implications for ventilator management.

Engineers from the University of Warwick are leading a project, which has received funding of £342,863 from EPSRC under the UK government’s program for research on COVID-19, to work with clinicians from the University of Nottingham over the next 18 months to investigate optimal strategies for mechanical ventilation of COVID-19 patients. {module INSIDE STORY}

The first results from the project have now been published in the paper, In-silico modeling of COVID-19 ARDS: pathophysiological insights and potential management implications in the journal Critical Care Explorations, an official journal of the Society of Critical Care Medicine, which aims to rapidly communicate new ideas and innovations of relevance to clinical practice.

Researchers adapted a state-of-the-art computational simulator, which has been developed to investigate mechanical ventilation in conventional ARDS, to provide new evidence that the particular characteristics of COVID-19 ARDS may be the result of the virus disrupting blood flow through the lung – blocking blood flow to functioning areas by constricting blood vessels and/or causing tiny clots called microthrombi and diverting blood flow to damaged areas of the lung. Evaluation of some mechanical ventilation strategies using this model showed that they could be ineffective or even injurious to the lungs of certain COVID-19 patients.

“Some ventilation strategies could be ineffective or even cause damage to patients if they don’t adequately reflect their individual pathophysiology – given the heterogeneity of COVID-19 ARDS patients, a personalized approach to treatment is vital,” said Professor Declan Bates, the Principal Investigator from the School of Engineering at the University of Warwick.

“Our interdisciplinary group of engineers and clinicians is leading worldwide efforts to exploit the power of computational modeling to rapidly advance our understanding of COVID-19 pathophysiology, and develop personalized ventilation strategies for this challenging disease," said Professor Jonathan Hardman, the Principal Investigator from the School of Medicine at the University of Nottingham. “Traditional approaches to investigating the complex pathology of poorly understood diseases (such as COVID-19 critical illness) tend to yield inconclusive results due to the difficulty of clinical data collection and the inherent noise in the data.

“Our approach, using high-fidelity, deeply-validated modeling allows rapid exploration of the mechanisms of disease states, and pre-clinical testing of potential therapeutic approaches, accelerating the development of effective treatments for the devastating critical illness that can develop in COVID-19.”

0.5°C of additional warming has a huge effect on global aridity

Tyler O'Neal, Staff Editor GOVERNMENT

In a new climate modeling study, researchers from the Institute of Industrial Science, The University of Tokyo have revealed major implications for global drought and aridity when limiting warming to 1.5°C rather than 2°C above pre-industrial levels. Drought has serious negative impacts on both human society and the natural world and is generally projected to increase under global climate change. As a result, assessment of the risk of drought under climate change is a critical area of climate research.

In the 2015 Paris Agreements, the United Nations Framework Convention on Climate Change (UNFCCC) proposed that the increase in global average temperature should be limited to between 1.5°C and 2°C above pre-industrial levels to limit the effects of severe climate change. However, there have been few studies focusing on the relative importance of this 0.5°C of global average temperature rise and what effect it might have on drought and aridity around the world. 97f603f46265a3146c683830d614398ec7560d54 232e4

"We wanted to contribute to the understanding of how important that 0.5°C could be, but it such a study is not easy to conduct based on previous modeling approaches," explains corresponding author Hyungjun Kim. "This is mainly because most models look at the extreme high levels and you cannot simply take a slice out of the data while the model spins up to this maximum. Therefore, we used data from the specially designed Half a degree Additional warming Prognosis and Projected Impacts (HAPPI) project to assess the impacts on aridity based on estimations of the balance between water and energy at the Earth's surface."

The study revealed that 2°C of warming led to more frequent dry years and more severe aridification in most areas of the world compared with 1.5°C, which emphasizes that efforts should be made to limit warming to 1.5°C above pre-industrial levels.

"There is a really strong message that some parts of the world could have more frequent drought at 2°C than at 1.5°C. This situation could be especially severe in the Mediterranean, western Europe, northern South America, the Sahel region, and southern Africa," says lead author Akira Takeshima. "However, this situation is highly regional. In some parts of the world, like Australia and some of Asia, the opposite situation was simulated, with a wetter climate at 2°C than at 1.5°C."

These findings show the importance of considering the regional impacts of the additional 0.5°C of warming, especially with respect to any future relaxation of the 1.5°C target.