The simplest group of multicellular animals, the sponges, is not so simple. “Researchers have long regarded sponges as the most primitive form of animal life,” wrote Helen Pilcher in Nature;1 “At first glance, sponges seem simple. They have no gut, no brain, no obvious front or back, left or right. Adults pump water through a system of canals and cavities to extract food.” That apparent simplicity belies some pretty advanced technologies possessed by these creatures. Pilcher mentions several (emphasis added in all quotes):They contain a diversity of cell types; one species contains “at least 11 specialized cell types arranged in a particular pattern.”They contain collar cells with whip-like tails that create currents in the body to ingest food and excrete waste.They produce sperm and egg cells.They have an epithelial layer that provides protection.They make use of a cellular adhesive, integrin, that works with collagen to provide a tether.They communicate with signals that tell developing embryonic cells where to go. “Like more complex animals,” Pilcher writes, “sponges solve this problem by using specific molecules to guide differentiation and migration as the cells develop in their embryos.”These and other characteristics of sponges suggest to evolutionary biologists that the genetic toolkit for these functions was already present in a putative unicellular ancestor before the first metazoan emerged. It seems that the unknown ancestor must have already been “a sophisticated creature.” Later, in Science,2 more marvels about the sponge called Venus Flower Basket were revealed (see 03/01/2004 entry). Not only does it know how to create high-performance, flexible fiber optic cable at low temperatures; now, says MSNBC News, it is able to “build glass cages that have biologists and materials scientists oohing, ahhing and taking notes for future bio-inspired engineering projects and materials.” Reporter Daniel B. Kane continues, “These glass cages have at least seven levels of structural organization, many of which follow basic principles of mechanical engineering,” referring to the paper by Aizenberg et al. who wrote in the abstract, “The ensuing design overcomes the brittleness of its constituent material, glass, and shows outstanding mechanical rigidity and stability. The mechanical benefits of each of seven identified hierarchical levels and their comparison with common mechanical engineering strategies are discussed.” Their opening paragraph puts this discovery in context:Nature fascinates scientists and engineers with numerous examples of exceptionally strong building materials. These materials often show complex hierarchical organization from the nanometer to the macroscopic scale. Every structural level contributes to the mechanical stability and toughness of the resulting design. For instance, the subtle interplay between the lattice structure, fibril structure, and cellulose is responsible for the remarkable properties of wood. In particular, it consists of parallel hollow tubes, the wood cells, which are reinforced by nanometer-thick cellulose fibrils wound helically around the cell to adjust the material as needed. Deformation occurs by shearing of a matrix rich in hemicelluloses and lignin, “gluing” neighboring fibrils, and allowing a stick-slip movement of the fibrils. Wood is an example that shows the wide range of mechanical performance achievable by constructing with fibers. Bone is another example of a hierarchically assembled fibrous material. Its strength critically depends on the interplay between different structural levels—from the molecular/nanoscale interaction between crystallites of calcium phosphate and an organic framework, through the micrometer-scale assembly of collagen fibrils, to the millimeter-level organization of lamellar bone. Whereas wood is fully organic material, bone is a composite, with about half organic and half mineral components tightly interconnected at the nanoscale. However, nature has also evolved almost pure mineral structures, which—despite the inherent brittleness of most minerals—are tough enough to serve as protection for the organism. In mollusk nacre, for example, the toughening effect is due to well-defined nanolayers of organics at the interfaces between microtablets of calcium carbonate. In such structures, the stiff components (usually mineral) absorb the bulk of the externally applied loads. The organic layers, in turn, provide toughness, prevent the spread of the cracks into the interior of the structure, and even confer a remarkable capacity for recovery after deformation.From here, they discuss how the Venus Flower Basket builds its glass house from the bottom up with each level of organization contributing to the high performance of the end product. Their concluding paragraph seems to contain mixed metaphors: design and evolution—The structural complexity of the glass skeleton in the sponge Euplectella sp. is an example of nature’s ability to improve inherently poor building materials [e.g., glass]. The exceptional mechanical stability of the skeleton arises from the successive hierarchical assembly of the constituent glass from the nanometer to the macroscopic scale. The resultant structure might be regarded as a textbook example in mechanical engineering, because the seven hierarchical levels in the sponge skeleton represent major fundamental construction strategies such as laminated structures, fiber-reinforced composites, bundled beams, and diagonally reinforced square-grid cells, to name a few. We conclude that the Euplectella sp. skeletal system is designed to provide structural stability at minimum cost, a common theme in biological systems where critical resources are often limited. We believe that the study of the structural complexity of unique biological materials and the underlying mechanisms of their synthesis will help us understand how organisms evolved their sophisticated structures for survival and adaptation and ultimately will offer new materials concepts and design solutions.In the same issue of Science,3 John Currey provided details on six of the levels of organization investigated by Aizenberg et al.:Euplectella is a deepwater sponge whose glassy skeleton is a hollow cylinder. On the first level of structural hierarchy, nanometer-sized particles of silica are arranged around an organic axial filament. On the second level, alternating layers of silica and organic material form spicules. On the third level, these small spicules are bundled together to form larger spicules. On the fourth level, the larger spicules are arranged in a grid, with struts in longitudinal, circumferential, and diagonal directions, resisting all load modes (see the figure). In the mature animal, these larger spicules are coated with a cementing layer of silica. On the fifth level, this grid is wrapped into a curved cylinder. Finally, on the sixth level, helical surface ridges further resist torsion and stiffen the structure. Currey was most intrigued with level four, a “most remarkable feature” with its cross-beams and struts providing load strength and protection from shear. The MSNBC article contains three photos illustrating the architecture in this “primitive” metazoan. Aizenberg told the reporter, “It puzzles me. In my wildest dreams I can’t imagine how these fibers are assembled to make the nearly perfect, highly regular square cells, diagonal supports and surface ridges of the cage.” Despite the simplicity of the sponge’s anatomy, possessing no brain or nervous system, these structures represent “some of the most complex and diverse skeletal systems known.”1Helen Pilcher, “Back to our roots,” Nature 435, 1022-1023 (23 June 2005) | doi: 10.1038/4351022a.2Aizenberg et al., “Skeleton of Euplectella sp.: Structural Hierarchy from the Nanoscale to the Macroscale,” Science, Vol 309, Issue 5732, 275-278 , 8 July 2005, [DOI: 10.1126/science.1112255]3John D. Currey, “Materials Science: Hierarchies in Biomineral Structures,” Science, Vol 309, Issue 5732, 253-254 , 8 July 2005, [DOI: 10.1126/science.1113954].Wild dreams and imagination are not science; they indicate that Aizenberg is in a philosophical slumber by attributing engineering to evolution. If evolution produced this sponge’s architecture, as assumed by faith by these investigators, each stage must have contributed to an end result. Stage four would not help unless the lower stages in the hierarchy were already conferring their benefits; it would be like trying to build struts out of crumbly styrofoam or bits of broken glass. But end results are prohibited by evolutionary theory which stresses that evolving organisms have no goal in mind. In the Nature article, Simon Conway Morris extolled Tinker Bell: “Evolution is an extremely dynamic system and paradoxically a very lazy one. It will co-opt whatever it can.” Evolutionists preach that laziness and tinkering with available parts produced wonders of engineering that are the envy of materials science. It’s time to replace Darwin’s tomb in Westminster Abbey with Kepler’s, and change the objective of science from explaining away God back to thinking God’s thoughts after Him. This will lead to productive inquiry in science. Notice that the researchers here were oohing and ahhing not over Charlie’s little outworn myth, but over the engineering design apparent in the lowly sponge.(Visited 30 times, 1 visits today)FacebookTwitterPinterestSave分享0
20 June 2014The second day of debate on President Jacob Zuma’s State of the Nation address saw heated exchanges between Members of Parliament in Cape Town on Thursday, with presiding officer Thandi Modise, chairperson of the National Council of Provinces, frequently called upon to rule on objections to MPs’ statements.“It’s the nature of parliaments,” observed one international journalist who recorded the debate from the media gallery. “You go all over the world, parliaments are like this. It’s better here. In some countries, MPs even resort to physical fights.”Zuma, seated next to Deputy President Cyril Ramaphosa, listened attentively throughout. The President will respond to the debate on Friday.As things got heated up, it was Higher Education Deputy Minister Mduduzi Manana who chose to steer away from politics and mud-slinging.“The National Development Plan requires that by 2030, at least 30 000 qualified artisans are produced per year. Our department is on a mission to champion artisanship as a career choice,” Manana said, adding that 2014 had been declared the Year of Artisans.Zuma said in his address on Tuesday that South Africa needed “engineers, electricians, plumbers, doctors, teachers and many other professionals to build our country’s economy.“Education therefore remains an apex priority for this government,” Zuma said, announcing that contractors would be moving on site in September to build South Africa’s two new universities, Sol Plaatie in the Northern Cape and the University of Mpumalanga in Nelspruit.“By January next year, the first intake of medical students will be enrolled at the new medical university in Limpopo,” he added. “In addition, 12 training and vocational education colleges will be built to expand the technical skills mix in the country.”On Thursday, Manana said the Department of Higher Education would be building skills centres in communities across the country to train people to help meet local economic needs.“We will also prioritise the areas of career guidance and dissemination of information to curb the skills mismatch that we find in the country,” he said.Deputy Communications Minister Stella Ndabeni-Abrahams used her debate slot to call on young people to help come up with solutions to the challenges the country was facing.“Today as we engage in the struggle to defeat unemployment, poverty and inequality, we count young people among the main contributors and those who stand to gain the most from this struggle,” she said.Ndabeni-Abrahams said work to professionalise the public service was continuing, with the recent introduction of the School of Government set to improve the capacity of public servants.“These interventions will assist us to forge a disciplined, people-centred, efficient and professional public service. They will help us to infuse within our public service the Batho Pele (people first) principles,” she said.Source: SAnews.gov.za
Share Facebook Twitter Google + LinkedIn Pinterest The Ohio Cattlemen’s Association Annual Meeting and Awards Banquet was held in January in Lewis Center at the Nationwide Hotel and Conference Center. More than 200 attended the event that offered educational breakout sessions, several new youth opportunities, the annual meeting, and evening banquet.“We got an update from Washington, D.C. We heard about where we stand on the electronic logging devices, which is a big issue for a lot of our members and we talked about water quality issues. We also had our first annual youth quiz bowl and we had 42 individuals participate. We are trying to get some more of the youth involved in what we are doing here,” said Sasha Rittenhouse, the new Ohio Cattlemen’s Association president. “One of the biggest things I am looking forward to as president is giving back to an association that I truly believe benefits every single beef producer in the state. The OCA does so many things that a lot of people do not realize. We go to the State House and Washington, D.C. when there are issues trying to put a face with a name. We want to make sure they realize that, though there are not many of us, we are feeding people around the world.”Meeting attendees heard from industry resource speakers including Alvaro Garcia Guerra with Ohio State University talking about pregnancy loss in beef cattle. Other featured speakers at the event included Cathann Kress, dean of the OSU College of Food Agriculture and Environmental Sciences, John Foltz, chair of the OSU Department of Animal Sciences, and Colin Woodall, with the National Cattlemen’s Beef Association, who offered insights into issues at the federal level.“The overall attitude when you look at the beef cattle industry is one where the current administration cares a little bit more about what we have to say. That has been encouraging for us with any number of issues right now. Having an administration that wants to talk with us and help to fix our problems has made 2017 a whole lot better. We look forward to more wins in 2018. With what you hear in the national media it sounds like a bunch of chaos, but from a beef cattle perspective it has been a good year,” Woodall said. “There were two huge wins for us in 2017. One was the rollback of EPA’s WOTUS rule and the other was re-opening China to U.S. beef. Both of those we had spent over a decade working on.“Of course the President has made it clear that he wants to renegotiate NAFTA. As long as we don’t touch the beef and cattle trade provisions we are fine with that. It has worked really well since that agreement has been put into place and we have to maintain our access to Canada and Mexico that are both in our top five for export markets. Our domestic herd is growing and we have to be able to move that product. Having access to Canada and Mexico is a key component of that.”Another issue is a battle over food product labeling.“We do not want the vegetable-based products or lab test tube-based products to be able to use our terminology like beef or hamburger. We don’t mind if people want to find new ways to produce protein we just don’t want them to use our nomenclature because we have worked hard to build the names around our business and we don’t want the consumer to ever be confused,” Woodall said. “We are also going to continue to work on trade access to maintain the agreements we have and open up new markets. We have some work left on the environmental side too. There are still rules and regulations left over from the Obama Administration that we have left to fix. We hope to push forward to get a farm bill done before the current one expires in September.”In addition, awards were presented including: Gerber Farms, Middletown, Ohio — Commercial Producer of the Year; J & L Cattle Service, Jeromesville — Seedstock Producer of the Year; Kyle Nickles, Sycamore — Young Cattleman of the Year; Representative Brian Hill, Zanesville — Industry Service; Gibbs Farms, Maplewood — Environmental Stewardship; and E.R. Boliantz Co., Ashland — Industry Excellence.Fourteen scholarships were presented to outstanding youth during the luncheon. Josh Dickson, Licking County; Kady Davis, Carroll County and Meredith Oglesby, Highland County, received the $1,000 Cattlemen’s Gala scholarship, funded by the 2017 inaugural event. Cole Liggett, Tuscarawas County; Emily Horst, Wayne County; McKayla Raines, Adams County and Erica Snook, Noble County were awarded $1,000 Tagged for Greatness Scholarships, which are funded with the sales of the Ohio Beef license plate.Desirae Logsdon, Fairfield County; Garret Stanfield, Adams County; Caitlyn Gaddis, Knox County and Evan Smith, Fairfield County, received a $1,000 Country Club Scholarship, which was funded by the putt-putt course at the 2017 Ohio State Fair.Hannah Frobose, Wood County, was awarded the $1,000 William Cleland Memorial scholarship. Natalie Wagner, Brown County, was awarded the Saltwell Expo scholarship, funded by the Saltwell Western Store and Ohio Beef Expo, that will be presented at the 2018 Ohio Beef Expo in March. Colin Woodall, NCBA Young Cattleman Award winner Kyle Nickles from Ashland and Wayne counties Industry Service Award winner State Rep. Brian Hill from Muskingum County Seedstock Producer of the Year winners Jeff and Lou Ellen Harr of J&L Cattle Services of Ashland County Environmental Stewardship winners Chris and Jason Gibbs from Shelby and Logan counties Commercial Producer of the Year Gary Gerber and family from Butler County Sasha Rittenhouse, the new Ohio Cattlemen’s Association president Joe Foster hands the gavel to Sasha Rittenhouse, the current Ohio Cattlemen’s Association president. Industry Excellence Award winner Bob Boliantz of E.R. Boliantz Co. packing company in Ashland.