Tag: 上海干磨论坛

New Book Reveals China’s Cambrian Explosion

first_imgNature July 221 has a book review about the first volume in English of the Chengjiang biota of China, where tens of thousands of soft-bodied organisms are preserved in early Cambrian strata.  The book, The Cambrian Fossils of Chengjiang, China: The Flowering of Early Animal Life by Xian-Guang Hou et al., is praised by reviewer Zhe-Xi Luo, who puts a positive spin on the problem of the Cambrian explosion:These beautiful and unique fossils have inspired new scientific insights and led to the clashing of ideas.  There is a great debate on the likely positions of Chengjiang animals such as the yunnanozoans in the deuterostome family tree.  Such debates will surely redefine the phylogenetic framework for establishing the earliest evolution of key features of chordates….….it also provides an update on the fast-paced attempts to decipher the full evolutionary significance of this palaeontological treasure…..….The early animal fossil record, however incomplete, can tell us about the early diversification of major animal lineages, a hot topic for molecular evolutionary studies, especially with regard to the timing of early animal evolution.  The Chengjiang fossils are the best source of evidence about the emergence of animal body plans, and have attracted interest from students of evolutionary development….….the Early Cambrian sea of Chengjiang really is a cradle of early chordate evolution.In the film Icons of Evolution, paleontologists onsite at the Chengjiang beds demonstrate that while soft-bodied fossils appear in the early Cambrian beds, including items as delicate as sponge embryos, no fossils appear in the preCambrian beds just below them, even though conditions were suitable for preservation.  The paleontologists also explain that all the phyla appear abruptly in the Cambrian beds.  Biodiversity actually decreases in the higher layers, contrary to the predictions of Darwin’s tree of life diagram.    In the same issue, Andrew B. Smith2 comments on a fossil found in the same Chengjiang beds by D. -G. Shu and Simon Conway Morris et al.3 that they claim is a primitive echinoderm.  The phylogeny of echinoderms, which includes starfish and sea urchins, has long been a puzzle.  “If correct” about this fossil claimed to be 520 million years old, he asserts, “this links the echinoderms to an enigmatic group, the vetulicolians, remains of which are found in the same deposits of early Cambrian age.”  Making the connection with this enigmatic group poses a major difficulty, he says, “because of the difficulty of interpreting even their basic anatomical organization.”  Although echinoderms are placed within the deuterostomes (a “very diverse group” of animals with a mouth and anus which includes all the vertebrates), “in terms of morphology echinoderms have always stood apart because of their aberrant symmetry and lack of structures known as gill slits” unique to deuterostomes.  Starfish, with their five-fold symmetry radiating from a center, don’t fit the pattern of other deuterostomes.  Smith seems to remain unconvinced of the connection at this point:There is now direct fossil evidence that all of the major deuterostome groups were established by about 520 million years ago.  Fossil vertebrates (yunnanozoans), tunicates (Shankouclava) and both asymmetric and radiate echinoderms (homalozoans, helicoplacoids) have all now been discovered in early Cambrian deposits.  Phlogites, a tentacle-bearing early Cambrian fossil of uncertain affinity, might even be a hemichordate or part of the common ancestral lineage of echinoderms and hemichordates.  So, if deuterostome divergence occurred around 575 million years ago, as recent molecular-clock studies suggest, there is a 50-million-year gap in the fossil record between the origin of deuterostomes and their appearance in the fossil record.  In the jigsaw of deuterostome evolution, vetulocystids represent another piece to be fitted into a puzzle where many of the pieces are still missing.1Zhe-Xi Luo, “A window on early animal evolution,” Nature 430, 405 (22 July 2004); doi:10.1038/430405a.2Andrew B. Smith, “Paleontology: Echinoderm roots,” Nature 430, 411 – 412 (22 July 2004); doi:10.1038/430411a.3Shu, D. -G., Conway Morris, S., Han, J., Zhang, Z. -F. & Liu, J. -N. Nature 430, 422�428 (2004).The spinmeisters of the Darwin Party, like this book reviewer, sound for all the world like a Stalinist explaining the benefits of the new Five-Year Plan.  Smith seems to be saying “not so fast” as he owns up to the mystery of the Cambrian explosion: all the major groups of animals, including vertebrates, appear suddenly in the early Cambrian without ancestors.  Think of all the changes that must take place to turn an organism with bilateral symmetry into one with pentaradiate symmetry like a starfish.  The first uncontested fossil echinoderm is already a full-fledged echinoderm.  Why is this so puzzling?  It’s only a puzzle if you’re trying to draw a mythical tree between the dots that is only a figment of philosophical imagination.For an excellent overview of the Cambrian explosion and the challenge it poses to Darwinian evolution, see The Cambrian Explosion: Biology’s Big Bang by Meyer, Ross, Nelson and Chien (12/01/2003) available online at the Discovery Institute.(Visited 11 times, 1 visits today)FacebookTwitterPinterestSave分享0last_img read more

Coconut Oil Facts

first_imgBy Christian Augusto Maino Vieytes, M.S. Candidate, Division of Nutritional Sciences, University of IllinoisCoconut OilCooking with oil is a staple dietary custom across an expanse of cultures. The use of coconut oil as a mainstream cooking oil has garnered attention within the last decade and is often labeled a “functional food”. Many have advanced the idea that this plant-based oil is a healthier alternative to butter and other oils, but does the evidence back such claims?Saturated Fat: Are They All Created Equal?The evils of saturated fat have been well documented by academics and the news media. Consumption of saturated fat has been demonstrated to perpetuate cardiovascular disease by increasing levels of “bad” cholesterol, known in the scientific community as the LDL cholesterol level, at the expense of “good” cholesterol, HDL. If such a claim is true then we would expect consumption of coconut oil, which is comprised of up to 90% saturated fat, to deliver an egregious attack on your arteries. Moreover, proponents of coconut oil-use and wholesalers have claimed that the saturated fat profile of coconut oil is “healthier” than that found in animal products. Let’s take a look at what the science has to say.The ScienceNumerous studies have been carried out and arrived at the conclusion that incorporating coconut oil into the diet is associated with an increase in total cholesterol. This includes observed jumps in both “bad” (LDL) and “good” (HDL) cholesterol levels. Compared to other dietary sources of saturated fat, coconut oil was only surpassed in its LDL-raising capability by animal-derived butter. Sticking to a plant-derived oil such as safflower oil or olive oil, which unlike animal fat or coconut oil is abundant in unsaturated fats, was found to not be as damaging and has been suggested, by many studies, to have a profound LDL-lowering effect.Plant sources tend to have a higher unsaturated fat content and provide additional nutritional benefits, such as packing vitamins and antioxidants. Coconut oil provides a rich source of antioxidant compounds called phenolics despite it being very high in saturated fat. However, the same class of beneficial compounds are found in other plant-oils such as virgin olive oil, which pack only miniscule amounts of saturated fat. The methods of oil extraction also significantly affect the levels of these compounds in the oil. Cold extraction methods (you might see this labeled “cold-pressed” on products at your local grocery store) tend to retain higher levels of these chemicals.The Take-Home MessageThe source of your dietary fat is very important. Plant oils tend to be substantially healthier than animal fats and can contribute to the prevention of cardiovascular disease, given that they boast lower amounts of saturated fat. However, as a general rule of thumb, it is always best to cut down on processed foods. Coconut oil and other plant-sourced oils are calorically-dense, refined, and processed products that are easy to overconsume since they have been taken out of the context of the whole food they originate from. Incorporating whole-food fat sources, such as avocados and nuts, is an easier approach for acquiring these essential plant-derived fats and nutrients without the propensity to overconsume them. BibliographyAmarasiri, W. A., and A. S. Dissanayake. “Coconut fats.” The Ceylon medical journal 51.2 (2006): 47-51.Cox, C., et al. “Effects of dietary coconut oil, butter and safflower oil on plasma lipids, lipoproteins and lathosterol levels.” European journal of clinical nutrition 52.9 (1998): 650.Denke, Margo A. “Dietary fats, fatty acids, and their effects on lipoproteins.” Current atherosclerosis reports 8.6 (2006): 466-471.Eyres, Laurence, et al. “Coconut oil consumption and cardiovascular risk factors in humans.” Nutrition reviews 74.4 (2016): 267-280.Harris, Margaret, Andrea Hutchins, and Lisa Fryda. “The impact of virgin coconut oil and high-oleic safflower oil on body composition, lipids, and inflammatory markers in postmenopausal women.” Journal of medicinal food 20.4 (2017): 345-351.Marina, A. M., et al. “Antioxidant capacity and phenolic acids of virgin coconut oil.” International Journal of Food Sciences and Nutrition 60.sup2 (2009): 114-123.Marina, A. M., YB Che Man, and I. Amin. “Virgin coconut oil: emerging functional food oil.” Trends in Food Science & Technology 20.10 (2009): 481-487Owen, Robert W., et al. “Olive-oil consumption and health: the possible role of antioxidants.” The lancet oncology 1.2 (2000): 107-112.Willett, Walter C., et al. “Mediterranean diet pyramid: a cultural model for healthy eating.” The American journal of clinical nutrition 61.6 (1995): 1402S-1406S.last_img read more

Copa America: Messi rues draw

first_imgA frustrated Lionel Messi said a joke goal had complicated Argentina’s Copa America start as the hosts struggled to impose themselves in their 1-1 draw with Bolivia in the tournament’s first match on Friday. Argentina had to chase their Group-A opener from the 47th minute when an error by midfielder,A frustrated Lionel Messi said a joke goal had complicated Argentina’s Copa America start as the hosts struggled to impose themselves in their 1-1 draw with Bolivia in the tournament’s first match on Friday.Argentina had to chase their Group-A opener from the 47th minute when an error by midfielder Ever Banega allowed Bolivia to sneak into a shock lead before substitute Sergio Aguero equalised half an hour later.”They surprised us with a crap goal and we managed to draw thanks to Kun (Aguero), but we’re sad because we didn’t reach our objective. We did some things well but we have to keep improving,” Messi told reporters.Bolivia’s point in the match in La Plata was the first they have ever picked up in a competitive match on Argentine soil.It also denied Argentina revenge for a 6- 1 roasting under former coach Diego Maradona in a World Cup qualifier at high altitude in La Paz two years ago. ‘A night without altitude’ was the headline in the daily Clarin in a play on words on the expression in Spanish which would better translate as a night without class.Argentina played into the hands of a modest but well- organised Bolivia, failing to execute coach Sergio Batista’s passing game modelled on Messi’s club side Barcelona. “It’s very difficult to play like Barcelona, but the idea is ball possession,” Batista told reporters.”We tried to play and be a team with a lot of the ball, but Bolivia put a lot of people in the middle and clogged the spaces. It was a difficult debut.” Batista said on the eve of the match he had not recalled forward Carlos Tevez just because of popular demand. He explained that with the player of the people in his side he would get more football and less vertigo, meaning less headless running at the opposition defence.advertisementYet Tevez and Ezequiel Lavezzi, the two players flanking Messi in attack, did just that with the former earning some of the lowest match ratings in Saturday’s papers. Messi received an ovation from the crowd, but not for the reasons he would have liked, when he stood up to Bolivia’s captain Ronald Raldes after a clash.Colombia winStriker Adrian Ramos earned Colombia a 1-0 win over 10- man Costa Rica that put them top of Group-A after their first match at the Copa America on Saturday.Ramos beat the offside trap to run onto a through pass from winger Fredy Guarin, round goalkeeper Leonel Moreira and put the Colombians ahead seconds before half-time.Costa Rica had been reduced to 10 men after 27 minutes when forward Randall Brenes was shown a straight red card after a dangerous tackle on defender Luis Perea.Meanwhile, Brazil play Venezuela in their opener on Sunday and will be approaching the game with caution, after Argentina’s result.- With inputs from agencieslast_img read more

Reversal of roles

first_imgPhoto by Tristan Tamayo/INQUIRER.netAll it took was a long break and some really tough defense down the stretch.All of a sudden Magnolia has transformed from the team that was nearly pushed to the edge to the squad that is now a win from making it to the PBA Philippine Cup Finals.ADVERTISEMENT Private companies step in to help SEA Games hosting Somewhere in between, Victolero urged his team to let its defense hold sway. “They won’t beat us with outside shots,” he said during a timeout huddle.True enough Rain or Shine’s shooters began firing blanks in the fourth. Ed Daquioag buried two triples almost nine minutes apart, but in between, the Painters hit just a single field goal.Rain or Shine also missed three out of eight freethrows in that stretch and muffed three chances to take the lead there. The Hotshots forced two three-point misses from Yap and a turnover on a Painters fastbreak.After Yap’s second miss, Ian Sangalang padded Magnolia’s lead to 75-71. Norwood missed a triple and Rafi Reavis completed a three-point play that put the Hotshots up, 78-71, 1:36 remaining.Rain or Shine took 41 attempts from beyond the arc—the Painters only attempted 34 inside it—and made just 12.ADVERTISEMENT LATEST STORIES Panelo: Duterte ‘angry’ with SEA Games hosting hassles The Hotshots, brandishing a defense that reduced Rain or Shine to a three-point tossing crew, hammered out an 82-74 victory on Wednesday night at Cuneta Astrodome for a 3-2 series lead over the Elasto Painters.Magnolia can ice the series with a Game 6 victory on Friday after crawling out of a 0-2 hole in the race-to-four affair.FEATURED STORIESSPORTSPrivate companies step in to help SEA Games hostingSPORTSPalace wants Cayetano’s PHISGOC Foundation probed over corruption chargesSPORTSSingapore latest to raise issue on SEA Games food, logistics“We tried to focus more on defense and limit their score under 90. Defensively I’m proud of what we’ve done,” Magnolia coach Chito Victolero said, adding that the Lenten break helped his team find its legs in this series.The Hotshots raced to a 49-36 lead in the third period when Gabe Norwood caught fire, knocking down triples to spur a Painters rally. James Yap and Norbert Torres joined the fray with a triple each. Philippine Arena Interchange inaugurated Hontiveros presses for security audit of national power grid SEA Games hosting troubles anger Duterte Ateneo clinches twice-to-beatcenter_img DA eyes importing ‘galunggong’ anew MOST READ PH underwater hockey team aims to make waves in SEA Games PLAY LIST 02:42PH underwater hockey team aims to make waves in SEA Games01:44Philippines marks anniversary of massacre with calls for justice01:19Fire erupts in Barangay Tatalon in Quezon City01:07Trump talks impeachment while meeting NCAA athletes02:49World-class track facilities installed at NCC for SEA Games02:11Trump awards medals to Jon Voight, Alison Krauss View comments Duterte wants probe of SEA Games mess “We’re number one in points allowed in defense [in the past]. As long as our defense is in good shape, we do well,” Victolero said.Sports Related Videospowered by AdSparcRead Next Don’t miss out on the latest news and information. Cayetano: Senate, Drilon to be blamed for SEA Games messlast_img read more