News Article | February 15, 2017
Researchers have identified traces of what they believe is the earliest known prehistoric ancestor of humans - a microscopic, bag-like sea creature, which lived about 540 million years ago. Named Saccorhytus, after the sack-like features created by its elliptical body and large mouth, the species is new to science and was identified from microfossils found in China. It is thought to be the most primitive example of a so-called "deuterostome" - a broad biological category that encompasses a number of sub-groups, including the vertebrates. If the conclusions of the study, published in the journal Nature, are correct, then Saccorhytus was the common ancestor of a huge range of species, and the earliest step yet discovered on the evolutionary path that eventually led to humans, hundreds of millions of years later. Modern humans are, however, unlikely to perceive much by way of a family resemblance. Saccorhytus was about a millimetre in size, and probably lived between grains of sand on the seabed. Its features were spectacularly preserved in the fossil record - and intriguingly, the researchers were unable to find any evidence that the animal had an anus. The study was carried out by an international team of academics, including researchers from the University of Cambridge in the UK and Northwest University in Xi'an China, with support from other colleagues at institutions in China and Germany. Simon Conway Morris, Professor of Evolutionary Palaeobiology and a Fellow of St John's College, University of Cambridge, said: "We think that as an early deuterostome this may represent the primitive beginnings of a very diverse range of species, including ourselves. To the naked eye, the fossils we studied look like tiny black grains, but under the microscope the level of detail is jaw-dropping. All deuterostomes had a common ancestor, and we think that is what we are looking at here." Degan Shu, from Northwest University, added: "Our team has notched up some important discoveries in the past, including the earliest fish and a remarkable variety of other early deuterostomes. Saccorhytus now gives us remarkable insights into the very first stages of the evolution of a group that led to the fish, and ultimately, to us." Most other early deuterostome groups are from about 510 to 520 million years ago, when they had already begun to diversify into not just the vertebrates, but the sea squirts, echinoderms (animals such as starfish and sea urchins) and hemichordates (a group including things like acorn worms). This level of diversity has made it extremely difficult to work out what an earlier, common ancestor might have looked like. The Saccorhytus microfossils were found in Shaanxi Province, in central China, and pre-date all other known deuterostomes. By isolating the fossils from the surrounding rock, and then studying them both under an electron microscope and using a CT scan, the team were able to build up a picture of how Saccorhytus might have looked and lived. This revealed features and characteristics consistent with current assumptions about primitive deuterostomes. Dr Jian Han, of Northwest University, said: "We had to process enormous volumes of limestone - about three tonnes - to get to the fossils, but a steady stream of new finds allowed us to tackle some key questions: was this a very early echinoderm, or something even more primitive? The latter now seems to be the correct answer." In the early Cambrian period, the region would have been a shallow sea. Saccorhytus was so small that it probably lived in between individual grains of sediment on the sea bed. The study suggests that its body was bilaterally symmetrical - a characteristic inherited by many of its descendants, including humans - and was covered with a thin, relatively flexible skin. This in turn suggests that it had some sort of musculature, leading the researchers to conclude that it could have made contractile movements, and got around by wriggling. Perhaps its most striking feature, however, was its rather primitive means of eating food and then dispensing with the resulting waste. Saccorhytus had a large mouth, relative to the rest of its body, and probably ate by engulfing food particles, or even other creatures. A crucial observation are small conical structures on its body. These may have allowed the water that it swallowed to escape and so were perhaps the evolutionary precursor of the gills we now see in fish. But the researchers were unable to find any evidence that the creature had an anus. "If that was the case, then any waste material would simply have been taken out back through the mouth, which from our perspective sounds rather unappealing," Conway Morris said. The findings also provide evidence in support of a theory explaining the long-standing mismatch between fossil evidence of prehistoric life, and the record provided by biomolecular data, known as the "molecular clock". Technically, it is possible to estimate roughly when species diverged by looking at differences in their genetic information. In principle, the longer two groups have evolved separately, the greater the biomolecular difference between them should be, and there are reasons to think this process is more or less clock-like. Unfortunately, before a point corresponding roughly to the time at which Saccorhytus was wriggling in the mud, there are scarcely any fossils available to match the molecular clock's predictions. Some researchers have theorised that this is because before a certain point, many of the creatures they are searching for were simply too small to leave much of a fossil record. The microscopic scale of Saccorhytus, combined with the fact that it is probably the most primitive deuterostome yet discovered, appears to back this up. The findings are published in Nature. Reference: Jian Han, Simon Conway Morris, Qiang Ou, Degan Shu and Hai Huang. Meiofaunal deuterostomes from the basal Cambrian of Shaanxi (China). DOI: 10.1038/nature21072. Inset image: Photographs of the fossils show the spectacularly detailed levels of preservation which allowed researchers to identify and study the creature. Credit: Jian Han.
News Article | January 31, 2017
A bag-like marine creature from China could be human's earliest relative. In a study published on Jan. 30, scientists revealed that the sea creature that wriggled in seabed mud about 540 million years ago could be the earliest known animal in the evolutionary branch that eventually led to humans. Apes and monkeys are known to have evolutionary links with humans, who emerged 200,000 years ago, but paleontologist Simon Conway Morris, from the University of Cambridge, explained that humans have a series of evolutionary deeper ancestors than these primates. The creature called Saccorhytus coronaries, whose name means wrinkled sack, is an example of an ancient human relative. It lived during the Cambrian Period, the time of exceptional evolutionary experimentation when life experienced great increase in diversity. Creatures that emerged during this period include penis worms with teeth and crustacean-like animals. It was the time in history when the food chains were just beginning to assemble. "It was the beginning for the world as we know it now, a world that's dominated by active animals — things walking around, swimming around, not just sitting there," said paleobiologist Peter Van Roy, from Yale University who was not involved in the study. Saccorhytus, which has an oval body and a relatively big mouth for its size of about 1 millimeter, appears to be the most primitive member of the broad animal group known as deuterostomes, which include vertebrates such as reptiles, birds, fish, amphibians and mammals including humans. Animals known as echinoderms, which include sea urchins and starfish, as well as the hemichordates, which include acorn worms, also belong to this group. "We think that as an early deuterostome, this may represent the primitive beginnings of a very diverse range of species, including ourselves," Morris explained. Researchers used computed tomography scan and electron microscope to construct image of the ancient creature. Analysis of the creature's fossil revealed that it had a bilaterally symmetrical body, a characteristic passed down to its descendants including humans. It was also covered with a thin and flexible skin that hint it had some kind of muscles that may have helped it wriggle around in the water. The small, conical structures that encircle its mouth may have also allowed the water it swallowed to escape from its body. These structures were possibly the precursor of gill slits that are found in fish, the vanguard of vertebrates that appeared about 10 to 15 million years after the Saccorhytus. Paleontologist Degan Shu, from China's Northwest University, said that the creature, which looked like a miniscule black grain, offers scientists remarkable insight into the first stage of evolution of a group that led to fish and eventually to humans. "The bag-like body bears a prominent mouth and associated folds, and behind them up to four conical openings on either side of the body as well as possible sensory structures," researchers described the creature in a study published in the journal Nature. "An anus may have been absent, and correspondingly the lateral openings probably served to expel water and waste material." © 2017 Tech Times, All rights reserved. Do not reproduce without permission.
Wen J.,Rutgers University |
Tan R.,Rutgers University |
Liu S.,Rutgers University |
Zhao Q.,Northwest University |
Zhang X.,Rutgers University
Chemical Science | Year: 2016
Rhodium catalyzed asymmetric hydrogenation of both isoquinolines and quinolines provides a new method to synthesize chiral tetrahydroisoquinolines and tetrahydroquinolines. By introducing strong Brønsted acid HCl, anion binding between the substrate and the ligand was established to achieve high reactivity and high enantioselectivity (up to 99% conversion and 99% ee). An NMR study suggests an anion binding between the catalyst and the substrate. Deuterium labeling experiments reveal a plausible reaction pathway. © 2016 The Royal Society of Chemistry.
News Article | January 29, 2017
If you feel secure with your Android phone's lock pattern, think again. A group of researchers from the Lancaster University, Northwest University in China, and the University of Bath found out that Android's pattern lock system can be cracked in just five attempts. What's even more mind-boggling is that the more complicated the pattern used, the more it gets easier to crack, according to these security experts. The Pattern Lock is a security measure used to protect one's mobile devices. Despite the prevalence of fingerprint scanners in recently launched Android phones, many people still deem it as a greater alternative to PIN codes because it is easier to remember and easier to enter into their devices. In order to access their phones, users are given five attempts to draw a pattern over grid dots on their phone's screen before they are locked out. Using a sophisticated algorithm software, researchers were able to crack the code by filming and analyzing fingertip movements and positioning of the device. Researchers used 120 unique patterns that were collected from different users and were able to figure out more than 95% of the patterns in just 5 attempts. The researchers expressed their concern that this method could be used by thieves in order to gain access to stolen phones and obtain personal information. This algorithm can be used by attackers across the room inside a busy café or a restaurant. An attacker could pretend to be fiddling with a phone while surreptitiously filming an unsuspecting victim. "Pattern lock is a very popular protection method for Android devices. As well as for locking their devices, people tend to use complex patterns for important financial transactions such as online banking and shopping because they believe it is a secure system," says Dr. Zheng Wang of Lancaster University. "However, our findings suggest that using Pattern Lock to protect sensitive information could actually be very risky." The group also found out that the complicated patterns are the ones easier to crack because they narrow down the possible options. Guixin Ye, a researcher from Northwest University, added that it might even be safer to use shorter, simpler patterns instead of the more complex ones. The researchers also suggested that Android users cover their fingers while drawing the patterns on their phones or to change their devices' screen color and brightness to pre-empt an attack. © 2017 Tech Times, All rights reserved. Do not reproduce without permission.
Ma J.,Northwest University |
Jing G.,Northwest University |
Jing G.,NanoBiophotonics Center
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2012
The fracture mechanics was usually employed to explain the crack propagation in the deposition produced by drying colloidal suspension. However, more complex than conventional fracture, those cracks periodically distribute and make up a unique pattern. Inspired by the concept of spinodal decomposition, here we develop the theory to illustrate the possible mechanism of the spatial arrangement of the cracks. It indicates that before the cracks develop and propagate in the deposition under the law of fracture mechanics, the periodically distributed flaws are generated by the phase separation of colloidal clusters and solvent. Then the cracks originate at the sites of those flaws in terms of fracture mechanics. It concludes that the crack spacing results from the wavelength of the concentration fluctuation during the phase separation, linearly growing with the increase of the deposition thickness and initial particle concentration, which is consistent with experimental results. © 2012 American Physical Society.
Zaragoza M.S.,Kent State University |
Mitchell K.J.,Yale University |
Payment K.,Ohio Northern University |
Drivdahl S.,Northwest University
Journal of Memory and Language | Year: 2011
Relatively little attention has been paid to the potential role that reflecting on the meaning and implications of suggested events (i.e., conceptual elaboration) might play in promoting the creation of false memories. Two experiments assessed whether encouraging repeated conceptual elaboration, would, like perceptual elaboration, increase false memory for suggested events. Results showed that conceptual elaboration of suggested events more often resulted in high confidence false memories (Experiment 1) and false memories that were accompanied by the phenomenal experience of remembering them (Experiment 2) than did surface-level processing. Moreover, conceptual elaboration consistently led to higher rates of false memory than did perceptual elaboration. The false memory effects that resulted from conceptual elaboration were highly dependent on the organization of the postevent interview questions, such that conceptual elaboration only increased false memory beyond surface-level processing when participants evaluated both true and suggested information in relation to the same theme or dimension. © 2010 Elsevier Inc.
Liu X.,Northwest University |
Qiu W.S.,Northwest University
IEEE Transactions on Reliability | Year: 2011
This paper presents a method for planning multiple-step step-stress ALT (SSALT) with statistically independent competing risks. A statistical model is constructed and asymptotically c-, D-, and Ds-optimal ALT plans are developed. Because the asymptotical optimality might sometimes lead to impractical ALT plans with finite sample size, additional constraints are introduced, and the planning of ALT on the constrained design space is also studied. Finally, we provide a numerical example to illustrate the application of the proposed method. © 2011 IEEE.
Jie H.,Northwest University
Electronic Journal of Geotechnical Engineering | Year: 2016
Aiming at the reservoir characteristics of a large of micro fractures and brittle shale in Chuanxi shale gas reservoir, a new water-based drilling fluid system called strong inhibition and strong blocking polyamine imitation oil-based water-based drilling fluid system CXWBM-1 was prepared. The full Performance, inhibition property; plugging property; lubrication property; anti pollution property were evaluated through laboratory experiment. The results show that the Chuanxi shale sample second recovery rate for CXWBM-1 drilling fluid system was over 95%, and CXWBM-1 can block micro cracks or pores of 0.5-15μm and the loss of drilling fluid systems can be controlled in 2mL. CXWBM-1 system has low viscosity coefficient and friction coefficient, the system has good lubricating property. CXWBM-1 system also has salt resistance ability, calcium resistance ability and debris contamination resistance. The application of this new system in Xinye HF-1 well of Chuanxi shale gas reservoir showed that the new developed water-based drilling fluid system can prevent swelling of shale and collapse necking to ensure the safety drilling. The system has broad application prospects in the drilling of similar shale gas reservoirs. © 2016 ejge.
News Article | February 15, 2017
The ancestor of all vertebrates, including fish, reptiles and humans was a big mouth but apparently had no anus. The microscopic creature named Saccorhytus, after the sack-like features created by its elliptical body and large mouth, lived 540 million years ago. It was identified from microfossils found in China. “To the naked eye, the fossils we studied look like tiny black grains, but under the microscope the level of detail is jaw-dropping,” says team member Simon Conway Morris, of the University of Cambridge, in the UK. Researchers believe it was about a millimetre in size, lived between grains of sand on the sea bed and had a large mouth relative to the rest of its body. They also think the creature was covered with a thin, relatively flexible skin, had some sort of muscle system which could have made contractile movements and allowed it to move by wriggling. It probably ate by engulfing food particles, or even other creatures, but scientists were unable to find any evidence the animal had an anus. “If that was the case, then any waste material would simply have been taken out back through the mouth, which from our perspective sounds rather unappealing,” says Conway Morris. The creature is thought to be the most primitive example of a so-called “deuterostome” – a broad biological category that encompasses a number of sub-groups, including the vertebrates. “We think that as an early deuterostome this may represent the primitive beginnings of a very diverse range of species, including ourselves,” says Conway Morris. “All deuterostomes had a common ancestor, and we think that is what we are looking at here.” Saccorhytus gives us remarkable insights into the very first stages of the evolution of a group that led to the fish, and ultimately, to us, says team member Degan Shu, from Northwest University, in the US. The creature also had small conical structures on its body which may have been the evolutionary precursor of the gills we now see in fish. Most other early deuterostome groups are from about 510 to 520 million years ago, when they had already begun to diversify into vertebrates, sea squirts, echinoderms – animals such as starfish and sea urchins – and hemichordates, a group including things like acorn worms. Read more: Comb jelly videos are rewriting the history of your anus
News Article | September 9, 2016
G. pannuceum (from the Latin word "pannuceus," meaning "wrinkled") gets its name from the wrinkled sheath covering its midbody. Four species of parasitoid wasps have been discovered in northwest China, a new study reports. The new species belong to the genus Gasteruption. These wasps have slender bodies and inflated, club-shaped hind legs. They also have elongated necks, and keep their abdomens raised and hind legs dangling during their slow, quiet flights. Their heads have a satin-like sheen and long eyes that extend almost to their mouth, the researchers said. The four new species — G. bicoloratum, G. huangshii, G. pannuceum and G. shengi — have a body covering that resembles black leather with grooves and stitches. The bugs range in size from 0.3 inches (8 millimeters) long to 0.5 inches (13 mm) long, and females are typically larger than males. [Googly Eyes: Photos of Striking Wasp Faces] The newfound species are parasitoid wasps whose larvae are parasites that kill their hosts. Adults hover outside the nests of solitary bees. While females hover to find an opportunity to sneak their own eggs into solitary bee nests, males typically linger in search of these females. Using a long, tube-like organ, called an ovipositor, the female lays eggs inside bee nests. The emerging larvae feed on bee eggs and larvae, and the food reserves of the nest. The young wasps pupate in their hosts' nests and emerge as adults in spring. The adult wasps can be locally abundant at times, particularly when they are feeding on pollen and nectar at flowers, said Jiang-Li Tan, an entomologist in the College of Life Sciences at Northwest University in China. But, "they are not encountered frequently and, in many regions of the world, are rarely collected," she said. A total of 28 species of Gasteruption were known from China before the new finds. Tan's team discovered four new species in the mountainous region of China's Shaanxi and Ningxia provinces. Tan lives near the Qinling mountains in Shaanxi, and every weekend during spring and summer, she would drive there with her students to sample wasps. "I am not surprised to find four new species," Tan told Live Science in an email. She added that there are likely more wasp species waiting to be found. But, it is not easy to identify a new species, Tan said. A combination of characteristics such as the shape of the head and legs, length of ovipositor, skin pattern, body color, and wing pattern and color, were used. G. bicoloratum was found at an elevation of around 3,600 feet (1,100 meters) above sea level. The species gets its name from its bicoloured hind legs, which are ivory and yellowish-brown. At 0.05 inches (1.2 mm) long, the ovipositor of females is very short, the scientists note in the paper. [No Creepy Crawlies Here: Gallery of the Cutest Bugs] G. huangshii was named after Huang Shi Gong — believed to be a teacher of a Han Dynasty general — since the wasp was found near his statue. It was found at an elevation of 4,400 feet (1,350 m) above sea level. In females of this species, the ovipositor is very long, about 1.2 times the length of the body, the study finds. G. pannuceum (from the Latin word "pannuceus," meaning "wrinkled") gets its name from the wrinkled sheath covering its midbody. And, G. shengi was named after its collector, Mao-Ling Sheng, in recognition of his work on parasitoid wasps of China. The largest of the four new species, G. shengi wasps are covered in dense, silvery hair, the researchers wrote in the study. The findings were published online Aug. 23 in the journal ZooKeys. Copyright 2016 LiveScience, a Purch company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.