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La Gomera giant lizard

The La Gomera giant lizard is a lacertid species that can be found on the island of La Gomera, one of the Canary Islands. It is distinguishable from any other member of Gallotia by the intense white colour that covers its neck and area around the mouth, in spectacular contrast to its dark brown back; this lizard is diurnal and herbivorous, grows up to half a metre long. The females lay a single clutch annually of three to seven eggs on average, its population trend has been increasing since 2001. Apparent La Gomera giant lizards are listed in reports on La Gomera up to the 19th century, but not thereafter; the species was described from subfossil remains in 1985 having gone extinct by then. Spanish biologists led by Juan Carlos Rando rediscovered this species in 1999; the biologists found only six living individuals. The current population of the La Gomera giant lizard consists of 90 individuals remaining in the wild, a captive stock of about 44 animals; this species is now only known from two separate inaccessible cliffs 2 km apart, close to the Valle Gran Rey.

The La Gomera giant lizard is thought to have once ranged throughout much of La Gomera and in many habitat types. Nowadays it is found in the Parque Rural de Valle Gran Rey, the present range is less than one hectare and is restricted to dry cliffs with sparse vegetation; the La Gomera Giant Lizard is listed as Critically Endangered by the IUCN Red List. The species declined through overgrazing and predation by feral cats and rats. Nowadays the main threats are predation by feral cats, rock falls within its restricted range; the species is protected by international legislation, a species recovery plan is in place. On La Gomera, a captive breeding programme has been established in order to increase the number of individuals. To ensure the survival of the remaining populations and facilitate eventual reintroductions, the feral cat population around the species' range will need to be controlled. In his scientific description, the German zoologist R. Hutterer referred the subfossil remains from La Gomera to two subspecies of Gallotia simonyi with the differences being size related.

He named these Gallotia simonyi bravoana and Gallotia simonyi gomerana. Bischoff synonymized them to a single taxon. Barbadillo et al. decided for bravoana. Nogales et al. concurred as used Gallotia gomerana. Following the ruling of the International Commission on Zoological Nomenclature, gomerana is a junior synonym or bravoana, it is not unequivocally accepted. Lacerta.de: Gallotia bravoana image gallery. Retrieved 2007-FEB-25

James E. Roberts Bridge

The James E. Roberts Memorial Bridge is a 1,400 foot two-lane highway bridge on California State Highway 120, in Tuolumne County, California; the bridge spans the Tuolumne River just north of Lake Don Pedro, near the community of Chinese Camp. It opened in 1971. Named the Tuolumne River Bridge, it was renamed in 2007 in honor of James E. Roberts by legislative resolution. Roberts was the California Department of Highways project manager, his first project management assignment as a senior bridge engineer; the cost to create new highway signs was raised by private donations. Key members of the Tuolumne River Bridge project, in addition to Mr. Roberts, were Richard "Dick" Dokken, PE, as lead design engineer. Blechinger, PE, as independent design checkers. Herbert K. Jensen, PE, was Resident Engineer for Bridge Construction, John F. Harrington, PE, was assistant resident engineer; this bridge, located west of Yosemite, was necessitated by a new highway alignment the resulted from creation of the new Don Pedro Dam reservoir.

James Roberts laid out the bridge on a horizontal curve with a 1,200 foot radius curve to meet the requests of the highway engineers. Large bridges of this size were built straight, California bridges required a detailed seismic analysis. Normal weight concrete was used for foundations or bridge piers and lightweight concrete was used for the bridge deck; the superstructure was painted steel curved girders trucked into the site. The bridge had to be completed prior to the filling of the reservoir; the tallest column is about 230 feet high, so falsework for concrete superstructure was not practicable. The highway engineers requested that the bridge have a capability to be widened from 2-lanes of traffic to 4-lanes, as planning at the time assumed that a wider highway would be necessary by 1995; the columns and foundation system were thus designed to support a second superstructure. However, as of 2016, the highway and bridge remain at two lanes width, as the majority of north-south freeway traffic in central California is on I-5 or State Highway 99 in the flat Central Valley.

The nearby Highway 49 is a winding, scenic highway that follows the contours of the foothills of the Sierra Nevada Mountain range. The top 70 feet of the bridge columns have an equilateral triangular shape to support the four lanes of proposed superstructure; the initial 2-lanes were placed on the outside radius, so eccentric loading analysis of the columns was necessary. The foundation was excavated rock and is hexagonal in shape to stabilize the column; the column is reasonably attractive. Peter Kiewit and Sons built the bridge as general contract with a gravel access road using switchbacks into the sides of the Tuolumne River canyon walls. Custom steel column forms were manufactured at an on site concrete batch plant; the San Jose Steel Company was the steel superstructure fabricator. Pieces were brought in by truck. After column completion, steel girders were erected from the canyon floor, lifted from the cantilevered tips of the north and south girders; the bridge opened to traffic in 1971.

The designers received an AISC Medium Span Steel Bridge award in 1972 and a James F. Lincoln Arc Welding Foundation Award; the AISC jurors wrote. The clean curving superstructure and the sculptured piers are pleasing." 1. Dokken Richard A. Salveson Matthew, James E. Roberts – More than an Engineer's Engineer. ASCE Structure Magazine, Feb 2009, pp 48–49 2. Roberts, James E. Dokken Richard A. Golden Gate of the Motherload, Modern Welded Structures, Volume VI, James F. Lincoln Arc Welding, Cleveland, OH, pp A-67 to A-70. 3. AISC, AISC Prize Bridges -1972, American Institute of Steel Construction pages 8 & 9, 1972 pp 33 4. Roberts, James E. Effects of curing and falsework support periods on dead load deflections of reinforced concrete slab bridges: final report / prepared in cooperation with the U. S. Dept. of transportation, Federal Highway Administration 1972 California Department of Highways Caltrans 5. Roberts, James E. Esthetics in concrete bridge design / editors, Stewart C. Watson, M. K. Hurd. American Concrete Institute 6.

Roberts, James E. Marquez, T. Huang, C, Mangus A. Dykes, B. Marlow S. Rea1igning Ca1ifornia's 1-880 Freeway. Concrete International January 2000 pp. 22–27. 7. Roberts, James E. Maroney Brian Chapter 40 Seismic Retrofit Practice, Bridge Engineering Handbook, 1St ed. Chen, Wai-Fah, Duan Lian Ed. CRC Press, Boca Raton Florida. 8. Roberts, James E. Maloney Brian, Theory of California seismic bridge design and analysis for the beginner (Division of Structures, California Dept. of Transportation. 9. Alden, Don, et al. Oral History James E Roberts, California Department of Transportation Caltrans, pp 10. Kempton, Land Richard, et al. James E. Roberts Memorial, California Department of Transportation, DVD, 59 minutes 11. Roberts, James E. 50-Years as bridge engineer History James E Roberts, California Department of Transportation, DVD, March 14, 2001 11. Wilson, Nothing Earth-Shattering –Roebling Medal, Roads & Bridges Magazine, August 2001, www. ROADSBRIDGES.com pp 24–25