Approaches to date the Big Bang, which gave birth to the universe, rely on mathematics and computational modeling, using distance estimates of the oldest stars, the behavior of galaxies and the rate of the universe’s expansion. The idea is to compute how long it would take all objects to return to the beginning.

A key calculation for dating is the Hubble’s constant, named after Edwin Hubble who first calculated the universe’s expansion rate in 1929. Another recent technique uses observations of leftover radiation from the Big Bang. It maps bumps and wiggles in spacetime — the cosmic microwave background, or CMB — and reflects conditions in the early universe as set by Hubble’s constant.

However, the methods reach different conclusions, said James Schombert, a professor of physics at the UO. In a paper published July 17 in the Astronomical Journal, he and colleagues unveil a new approach that recalibrates a distance-measuring tool known as the baryonic Tully-Fisher relation independently of Hubble’s constant.

“The distance scale problem, as it is known, is incredibly difficult because the distances to galaxies are vast and the signposts for their distances are faint and hard to calibrate,” Schombert said.

Schombert’s team recalculated the Tully-Fisher approach, using accurately defined distances in a linear computation of the 50 galaxies as guides for measuring the distances of 95 other galaxies. The universe, he noted, is ruled by a series of mathematical patterns expressed in equations. The new approach more accurately accounts for the mass and rotational curves of galaxies to turn those equations into numbers like age and expansion rate.

His team’s approach determines the Hubble’s constant — the universe’s expansion rate — at 75.1 kilometers per second per megaparsec, give or take 2.3. A megaparsec, a common unit of space-related measurements, is equal to one million parsecs. A parsec is about 3.3 light years.

All Hubble’s constant values lower than 70, his team wrote, can be ruled out with 95 percent degree of confidence.

Traditionally used measuring techniques over the past 50 years, Schombert said, have set the value at 75, but CMB computes a rate of 67. The CMB technique, while using different assumptions and computer simulations, should still arrive at the same estimate, he said.

“The tension in the field occurs from the fact that it does not,” Schombert said. “This difference is well outside the observational errors and produced a great deal of friction in the cosmological community.”

Calculations drawn from observations of NASA’s Wilkinson Microwave Anisotropy Probe in 2013 put the age of the universe at 13.77 billion years, which, for the moment, represents the standard model of Big Bang cosmology. The differing Hubble’s constant values from the various techniques generally estimate the universe’s age at between 12 billion and 14.5 billion years.

The new study, based in part on observations made with the Spitzer Space Telescope, adds a new element to how calculations to reach Hubble’s constant can be set, by introducing a purely empirical method, using direct observations, to determine the distance to galaxies, Schombert said.

“Our resulting value is on the high side of the different schools of cosmology, signaling that our understanding of the physics of the universe is incomplete with the hope of new physics in the future,” he said.

Story Source:

Materials provided by University of Oregon. Original written by Jim Barlow. Note: Content may be edited for style and length.

Modern amphibians usually have four fingers on the forelimb (and never more), which is called a “four-rayed hand,” as opposed to our five-rayed hand. Of all groups of terrestrial vertebrates, amphibians show the greatest variation in the number of frontfingers Reptiles are the most conservative and usually have five. In birds, the finger bones in the wing have been lost completely. In mammals, the number of toes in the forelimb also varies greatly: Primates and raccoons have five, in horses only the third has survived, while in cattle and other even-toed ungulates fingers three and four remain. What they all have in common, however, is that this loss of toes or fingers originates from a five-ray pattern, which is why amphibians cannot be the ancestors of all these terrestrial vertebrate groups.

Exact number of toes is controversial

It has been known for some time that the earliest quadrupeds had significantly more fingers than five, such as Acanthostega, which had eight in the forelimb, or Ichthyostega with seven in the hind foot. As early as 300 million years ago, all but the five-fingered forms became extinct. The five-ray pattern was then retained in the real land animals, but was reduced again and again (see horses). The ancestors of today’s amphibians, the Temnospondyli, presented contradictory evidence of skeletons with four fingers, but also tracks that had five.

Temnospondyli is an important group of the early, very diverse quadrupeds. Some temnospondyls became as big as crocodiles, others were rather small. However, like all amphibians, they were dependent on water during their larval stage. Their most famous representatives include Eryops or Mastodonsaurus. “It’s also important to understand the evolution of modern amphibians, as this group probably evolved from the Temnospondyli,” says Dr. Dorota Konietzko-Meier from the Institute for Geosciences at the University of Bonn, who discovered and prepared the left forelimb of a Metoposaurus krasiejowensis in Krasiejów (southwest Poland).

However, despite the long history of research, the exact number of fingers in Metoposaurus and other temnospondyls is still controversial. “It’s remarkable that even in the case of the very well-researched Eryops, the skeletal reconstruction exhibited at the Muséum National d’Histoire Naturelle in Paris has five fingers, while only four fingers can be seen at the National Museum of Natural History in Washington,” says Ella Teschner, a doctoral student from Bonn and Opole. Lately, science has assumed that, similar to most modern amphibians, all Temnospondyli have only four toes in their forelimbs. This resulted in the five-toed footprints common in the Permian and Triassic periods being almost automatically assumed to not belong to Temnospondyli.

“The find from the famous Upper Triassic site Krasiejów in Poland therefore offers a new opportunity to study the architecture and development of the hand of the early quadrupeds,” says paleontologist Prof. Dr. Martin Sander from the University of Bonn. A considerably broader view of the entire group of Temnospondyli did not show a clear trend with regard to the five-ray pattern and suggested that the number of digits was not as limited in the phylogenetic context as was assumed. “Evidently, the temnospondyls were already experimenting with the four-ray pattern, and the five-ray pattern died out before the emergence of modern amphibians,” adds Sander.

Five fingers on each hand?

“Even if the ossification of five metacarpal bones described here was only a pathology, it still shows that a five-ray pattern was possible in Temnospondyli,” says Konietzko-Meier. However, it could not be assumed with certainty that the reduction in the number of fingers/digits from five to four always affected the fifth place on the hand in these fossil taxa. The possibility that some of the four-fingered taxa were caused by the loss of the first ray cannot be excluded. Sander: “The new finding of a five-fingered hand is particularly important for the interpretation of tracks, as it shows that a five-fingered forefoot print could also belong to the Temnospondyli and thus indicate a considerably wider distribution area of these animals.”

These results are also of general importance, since limb development plays an important role in evolutionary biology and medicine, and fossils may therefore provide important information for the evaluation of theories of hand development.

Story Source:

Materials provided by University of Bonn. Note: Content may be edited for style and length.

Published online by a team from Warwick Medical School in the Journal of Hypertension today (25 July), they argue that any effort to increase plant-based foods in your diet and limit animal products is likely to benefit your blood pressure and reduce your risk of heart attacks, strokes and cardiovascular disease. They conducted a systematic review of previous research from controlled clinical trials to compare seven plant-based diets, several of which included animal products in small amounts, to a standardised control diet and the impact that these had on individuals’ blood pressure.

Plant-based diets support high consumption of fruits, vegetables, whole grains, legumes, nuts and seeds, limiting the consumption of most or all animal products (mainly meat and diary).

High blood pressure is the leading risk factor globally for heart attacks, strokes and other cardiovascular diseases. A reduction in blood pressure has important health benefits both for individuals and for populations. Unhealthy diets are responsible for more deaths and disabilities globally than tobacco use, high alcohol intake, drug use and unsafe sex put together. An increased consumption of whole grains, vegetables, nuts and seeds, and fruit, as achieved in plant-based diets, could avert up to 1.7, 1.8, 2.5 and 4.9 million deaths globally respectively every year according to previous research.

Vegetarian and vegan diets with complete absence of animal products are already known to lower blood pressure compared to omnivorous diets. Their feasibility and sustainability are, however, limited. Until now, it has not been known whether a complete absence of animal products is necessary in plant-based dietary patterns to achieve a significant beneficial effect on blood pressure.

Lead author Joshua Gibbs, a student in the University of Warwick School of Life Sciences, said: “We reviewed 41 studies involving 8,416 participants, in which the effects of seven different plant-based diets (including DASH, Mediterranean, Vegetarian, Vegan, Nordic, high fibre and high fruit and vegetables) on blood pressure were studied in controlled clinical trials. A systematic review and meta-analysis of these studies showed that most of these diets lowered blood pressure. The DASH diet had the largest effect reducing blood pressure by 5.53/3.79 mmHg compared to a control diet, and by 8.74/6.05 mmHg when compared to a ‘usual’ diet.

“A blood pressure reduction of the scale caused by a higher consumption of plant-based diets, even with limited animal products would result in a 14% reduction in strokes, a 9% reduction in heart attacks and a 7% reduction in overall mortality.

“This is a significant finding as it highlights that complete eradication of animal products is not necessary to produce reductions and improvements in blood pressure. Essentially, any shift towards a plant-based diet is a good one.”

Senior author Professor Francesco Cappuccio of Warwick Medical School said: “The adoption of plant-based dietary patterns would also play a role in global food sustainability and security. They would contribute to a reduction in land use due to human activities, to global water conservation and to a significant reduction in global greenhouse gas emission.

“The study shows the efficacy of a plant-based diet on blood pressure. However, the translation of this knowledge into real benefits to people, i.e. its effectiveness, depends on a variety of factors related to both individual choices and to governments’ policy decisions. For example, for an individual, the ability to adopt a plant-based diet would be influenced by socio-economic factors (costs, availability, access), perceived benefits and difficulties, resistance to change, age, health status, low adherence due to palatability and acceptance.

“To overcome these barriers, we ought to formulate strategies to influence beliefs about plant-based diets, plant food availability and costs, multisectoral actions to foster policy changes focusing on environmental sustainability of food production, science gathering and health consequences.”

Details of the seven plant-based diets examined (Table 1 in the research paper):

Plant-based diet & principal components:

• Healthy Nordic diet — Higher content of plant foods, fish, egg, and vegetable fat, and lower content of meat products, dairy products, sweets, desserts, and alcoholic beverages
• High-fruit and vegetable diet — Increased consumption of fruit and vegetables. To further increase the polyphenolic load, some studies included regular dark chocolate content
• High-fiber diet — Fiber is found in varying levels in all plant foods and is most prevalent in whole grains and legumes. For this reason, most high-fiber diets focus on increasing wholegrain and legume consumption
• Lacto-ovo vegetarian diet — Defined as those that exclude the consumption of all meat, poultry, and fish but still include the consumption of dairy and eggs. The main components include fruit, vegetables, whole grains, legumes, and nuts and seeds
• DASH diet — Encourages the consumption of fruits, vegetables, whole grains, nuts and seeds, and low-fat dairy products and limits the intake of sweets, saturated fat, and sodium
• Mediterranean diet — The main components are daily consumption of vegetables, fruit, whole grains, olive oil, weekly consumption of legumes, nuts, fish, dairy, and eggs, and limited intake of meat
• Vegan diet — Consists of plant foods exclusively. No animal flesh or other animal-derived products (including dairy and eggs) are included. It is mostly low-fat and focuses on the consumption of whole plant foods like fruits, vegetables, whole grains, legumes, and nuts and seeds