A growth analysis technique for assessing habitat severity in tundra regions

first_imgThe results are reported of growth experiments carried out over three seasons on the sub-Antarctic island of South Georgia. The values obtained for relative growth rate, net assimilation rate and leaf area ratio for oats, radish and turnip are discussed and contrasted with values reported for temperate sites. A hypothesis is put forward to explain the consistent depression of Rw and FA whilst the intermittent depression of EA is linked with Warren Wilson’s theory of the inhibiting effects of sugar accumulation. The usefulness of this technique in ecological applications is examined with particular reference to tundra regions.last_img read more

A case study of lightning, whistlers, and associated ionospheric effects during a substorm particle injection event

first_imgSimultaneous ground-based observations of narrowband and broadband VLF radio waves and of cloud-to-ground lightning were made at widely spaced locations during the 1987 Wave-Induced Particle Precipitation (WIPP) campaign, conducted from Wallops Island, Virginia. Based on these observations, the first case study has been made of the relationships among located cloud-to-ground (CG) lightning flashes, whistlers, and associated ionospheric effects during a substorm particle injection event. This event took place 2 days after the strongest geomagnetic storm of 1987, during a reintensification in geomagnetic activity (Kp = 5) that did not affect the high rate of whistlers observed at Faraday Station, Antarctica (L = 2.46). At the time of the injection event, several intense nighttime thunderstorms were located over Long Island and the coast of New England, between 400 km northwest and 600 km north of the region geomagnetically conjugate to Faraday. About two thirds of the CG flashes that were detected in these thunderstorms during the hour following the injection event onset were found to be causatively associated with whistlers received at Faraday. During the same period the amplitude of the 24.0-kHz signal from the NAA transmitter in Cutler, Maine, propagating over the thunderstorm centers toward Wallops Island was repeatedly perturbed in a manner characteristic of previously reported VLF signatures of transient and localized ionization enhancements at D region altitudes. Though such enhancements may have been caused by whistler-induced burst electron precipitation from the magnetosphere, the data in this case are insufficient to establish a clear connection between the NAA amplitude perturbations and the Faraday Station whistlers. In view of the proximity of the NAA great circle path to the storm center, heating of the lower ionosphere by intense radiation from lightning may also have played a role in the observed VLF perturbations. The onset of each of the NAA signal perturbation events coincided with an intense cluster of radio atmospherics. Detailed temporal variations in the ELF (0.3–3 kHz) and VLF (3–30 kHz) power of similar “sferic clusters” correlated well with variations in the power of simultaneous “anomalous” optical events (AOEs) observed by a down-looking photodiode detector on a rocket at altitudes between 150 and 412 km.last_img read more

Tissue distribution of retinoids in common dolphins Delphinus delphis

first_imgExposure to organochlorines induces retinoid deficiency in mammals; hence, retinoids are potential biomarkers of the impact of these pollutants. Appropriate target tissues to monitor retinoids in cetaceans have not been properly identified because of a lack of information on the contribution of each tissue to total body retinoids. Therefore, we have addressed this issue by studying the contribution of the main body tissues to retinoids in 21 common dolphins obtained from incidental catches and in apparent good health and nutritive condition. Although concentrations in the liver were highest, those in blubber were also high and accounted for 43% of the total retinoid load of the compartments examined. As blubber can be obtained using non-invasive biopsy techniques, this tissue is proposed as a reliable indicator of retinoid status in cetaceans. However, blubber topographical variation in structure and composition requires standardization of sampling sites. Retinoid concentrations did not differ significantly between sexes or with body size for any of the tissues, but the lipid content of blubber strongly influenced these concentrations. Biopsies from healthy, free-ranging individuals are preferred to samples from stranded animals. Further research on the influence of factors (age, sex, reproductive condition, diet) that potentially affect retinoid levels is required to implement the use of retinoids as biomarkers of pollutant exposure in cetaceans.last_img read more

Age assignment of a diatomaceous ooze deposited in the western Amundsen Sea Embayment after the Last Glacial Maximum

first_imgReliable dating of glaciomarine sediments deposited on the Antarctic shelf since the Last Glacial Maximum (LGM) is challenging because of the rarity of calcareous (micro-) fossils and the recycling of fossil organic matter. Consequently, radiocarbon (14C) ages of the acid-insoluble organic fraction (AIO) of the sediments bear uncertainties that are difficult to quantify. Here we present theresults of three different methods to date a sedimentary unit consisting of diatomaceous ooze and diatomaceous mud that was deposited following the last deglaciation at five core sites on the inner shelf in the western Amundsen Sea (West Antarctica). In three cores conventional 14C dating of the AIO in bulk samples yielded age reversals down-core, but at all sites the AIO 14C ages obtained from diatomaceous ooze within the diatom-rich unit yielded similar uncorrected 14C ages between 13 51756 and 11 54347 years before present (a BP). Correction of these ages by subtracting the core-top ages, which probably reflect present-day deposition (as indicated by 210Pb dating of thesediment surface at one core site), yielded ages between ca. 10 500 and 8400 cal. a BP. Correction of the AIO ages of the diatomaceous ooze by only subtracting the marine reservoir effect (MRE) of 1300 a indicated deposition of the diatom-rich sediments between 14 100 and 11 900 cal. a BP. Most of these ages are consistent with age constraints between 13.0 and 8.0 ka for the diatom-rich unit, which weobtained by correlating the relative palaeomagnetic intensity (RPI) records of three of the sediment cores with global and regional reference curves. As a third dating technique we applied conventional radiocarbon dating of the AIO included in acid-cleaned diatom hard parts extracted from the diatomaceous ooze. This method yielded uncorrected 14C ages of only 511138 and 510638 a BP, respectively. We reject these young ages, because they are likely to be overprinted by the adsorption of modern atmospheric carbon dioxide onto the surfaces of the diatom hard parts prior tosample graphitisation and combustion for 14C dating. The deposition of the diatom-rich unit in the western Amundsen Sea suggests deglaciation of the inner shelf before ca. 13 ka BP. The deposition of diatomaceous oozes elsewhere on the Antarctic shelf around the same time, however, seems to be coincidental rather than directly relatedlast_img read more

New Last Glacial Maximum ice thickness constraints for the Weddell Sea Embayment, Antarctica

first_imgWe describe new Last Glacial Maximum (LGM) ice thickness constraints for three locations spanning the Weddell Sea Embayment (WSE) of Antarctica. Samples collected from the Shackleton Range, Pensacola Mountains, and the Lassiter Coast constrain the LGM thickness of the Slessor Glacier, Foundation Ice Stream, and grounded ice proximal to the modern Ronne Ice Shelf edge on the Antarctic Peninsula, respectively. Previous attempts to reconstruct LGM-to-present ice thickness changes around the WSE used measurements of long-lived cosmogenic nuclides, primarily Be-10. An absence of post-LGM apparent exposure ages at many sites led to LGM thickness reconstructions that were spatially highly variable and inconsistent with flow line modelling. Estimates for the contribution of the ice sheet occupying the WSE at the LGM to global sea level since deglaciation vary by an order of magnitude, from 1.4 to 14.1m of sea level equivalent. Here we use a short-lived cosmogenic nuclide, in situ-produced C-14, which is less susceptible to inheritance problems than Be-10 and other long-lived nuclides. We use in situ C-14 to evaluate the possibility that sites with no post-LGM exposure ages are biased by cosmogenic nuclide inheritance due to surface preservation by cold-based ice and non-deposition of LGM-aged drift. Our measurements show that the Slessor Glacier was between 310 and up to 655m thicker than present at the LGM. The Foundation Ice Stream was at least 800m thicker, and ice on the Lassiter Coast was at least 385m thicker than present at the LGM. With evidence for LGM thickening at all of our study sites, our in situ C-14 measurements indicate that the long-lived nuclide measurements of previous studies were influenced by cosmogenic nuclide inheritance. Our inferred LGM configuration, which is primarily based on minimum ice thickness constraints and thus does not constrain an upper limit, indicates a relatively modest contribution to sea level rise since the LGM of < 4.6 m, and possibly as little as < 1.5 m.last_img read more

Antarctic Ice Sheet elevation impacts on water isotope records during the Last Interglacial

first_imgChanges of the topography of the Antarctic ice sheet (AIS) can complicate the interpretation of ice core water stable isotope measurements in terms of temperature. Here, we use a set of idealised AIS elevation change scenarios to investigate this for the warm Last Interglacial (LIG). We show that LIG δ 18 O against elevation relationships are not uniform across Antarctica, and that the LIG response to elevation is lower than the preindustrial response. The effect of LIG elevation‐induced sea ice changes on δ 18 O is small, allowing us to isolate the effect of elevation change alone. Our results help to define the effect of AIS changes on the LIG δ 18 O signals, and should be invaluable to those seeking to use AIS ice core measurements for these purposes. Especially, our simulations strengthen the conclusion that ice core measurements from the Talos Dome core exclude the loss of the Wilkes Basin at around 128 ky.last_img read more

Juab Boys, Carbon Girls, win at Juab Invitational

first_img Tags: Delta/Juab/Manti/Richfield/Track and Field Written by FacebookTwitterLinkedInEmailNEPHI, Utah-Monday, Juab High School hosted the Juab Invitational, which was postponed from earlier this month because of bad weather. With this being the final tune-up before the prestigious BYU Invitational Friday and Saturday, several Mid-Utah Radio Sports Network athletes excelled.The Juab boys won the title, posting 141.5 points and edging second-place Manti, who finished with 130 points. Delta finished fourth overall with 68 points.Carbon’s girls won the title with 137 points, while Juab placed second overall with 111 points. Richfield was fourth with 55 points and Manti placed sixth overall with 51 points.The Richfield girls won the medley relay title in a time of 4:35.33 as the team consisted of Brynn Christensen, Brianna Davis-Mitchell, Passion Reitz and SeOnna Southwick.Manti’s boys won the medley relay crown, posting a time of 3:41 22 with a team comprised of Cooper Parry, Lance Fowles, Jaden Sterner and Riley Searle.Delta’s Savannah Nielson won the girls’ 110-meter hurdles title in a time of 16.84 seconds, while Juab’s Ronnie Walker swept the 100 and 200-meter dash titles in times of 12.75 and 26.29 seconds, respectively.Manti’s Lance Fowles won the boys’ 100-meter dash title in a time of 11.70 seconds and his teammate, Jordan Cheney swept the 1600 (4:43.47) and 3200 (10:20.23) meter run titles.The Manti boys also excelled in the 4 x 100 relay, posting a time of 46.77 seconds. In this event, the Templars’ team consisted of Keenan Moulton, Travis Thomson, Jaden Sterner and Lance Fowles.In the 300-meter hurdles, the girls’ champion was Delta’s Adi Nielson in a time of 47.84 seconds, while for the boys, Mcray Stevens took the title for Juab, in a time of 41.38 seconds.Delta’s Dallin Draper showcased his speed in the boys’ 200-meter dash, winning it in a time of 21.63 seconds.The girls’ 3200-meter run saw Juab’s Maura Williams take the title in a time of 12:34.79, easily outdistancing runner-up and teammate, Whitney Slater, who finished second in a time of 13:18.72.The Delta Rabbits took the boys’ 4 x 400 relay title in a time of 3:43.07. The Rabbits were represented in this event by Trey Brough, Jaymen Brough, Dax Brough and Oran Finlinson.In the girls’ long jump, Richfield’s Melissa Crane won the title with a leap of 17-00.25 feet.Juab’s Parley Kay won the boys’ high jump with a leap of 5 feet 8 inches  and his teammate, Jackson Rowley won the boys’ javelin title with a toss of 155-06 feet.Richfield’s Abigail Woolsey won the girls’ javelin crown with a toss of 110-07 feet while Reese Darrington of Juab won the boys’ shot put title, posting a toss of 43-00.50 feet.In the girls’ shot put, Kjerstin Birch of Manti won the title with a toss of 31-09 feet.Finally, the boys’ discus title was won by Juab’s Ty Durbin with a throw of 124-08 feet. April 30, 2018 /Sports News – Local Juab Boys, Carbon Girls, win at Juab Invitational Brad Jameslast_img read more

Utah Valley Men’s Basketball Hosts Western Colorado

first_img FacebookTwitterLinkedInEmailOREM, Utah-Wednesday, Utah Valley men’s basketball returns to action by hosting NCAA Division II foe Western Colorado of the Rocky Mountain Athletic Conference.The Wolverines currently own the nation’s third-longest home winning streak at 16 straight victories at the UCCU Center.The Wolverines are coming off a successful week which saw them win the MGM Main Event middleweight championship as well as a home game against North Dakota last Saturday.Utah Valley, currently at 4-3 on the season, is being outscored by opponents, 72.6-71.9. The Wolverines’ leading scorer is Jake Toolson, who averages 14.9 points per game and 3.6 rebounds per contestThe Mountaineers, of Gunnison, Colo., have taken down one Division I opponent this season already, upsetting Air Force 84-64 at Colorado Springs, Colo.  November 1.Western State is led by redshirt senior guard Quincy Harding, who averages 20 points per game. Fellow senior guard Brady Subart adds 15.6 points per game.The Mountaineers are 3-3 on the season and outscore opponents 82.3-77.8 on average this season. Brad James Written by November 28, 2018 /Sports News – Local Utah Valley Men’s Basketball Hosts Western Colorado Tags: Brady Subart/Gunnison Colorado/Jake Toolson/MGM Main Event/NCAA Division II/North Dakota/Quincy Harding/UCCU Center/UVU Men’s Basketball/Western Coloradolast_img read more

Prep Sports Roundup: 2/22

first_img2-A Girls Semifinals @ Weber State RICHFIELD, Utah-Kaylie Jenson amassed 11 points and 11 rebounds and Mackenzie Jones added 11 points and 6 boards as the South Sevier Rams overpowered Carbon 45-36 Friday at the Sevier Valley Center in the 3-A girls consolation bracket. Makenna Blanc had 9 points in the loss for the Dinos. The Rams are next in action Saturday at 10:00 am against Judge Memorial as the Rams and Bulldogs will play for 5th-6th place in the girls’ 3-A bracket. Tags: Carbon/Kaylie Jenson/Mackenzie Jones/Makenna Blanc/South Sevier RICHFIELD, Utah-Trey Miles amassed 21 points on 10-17 shooting and had a key layup to put the game away as the Morgan Trojans overpowered Manti 48-41 Friday in the 3-A semifinals at the Sevier Valley Center. Adam Huff had 16 points and 6 rebounds in the loss for the Templars. Manti will play for third-fourth place at 3:00 pm Saturday at the Sevier Valley Center. Morgan advances to the 3-A state championship game Saturday at 7:00 pm against Richfield. RICHFIELD, Utah-Joshua Thalman posted 21 points and 6 rebounds on 8-10 shooting and the Richfield Wildcats routed Emery 81-57 at the Sevier Valley Center Friday in the 3-A semifinals. Emmitt Hafen posted 17 points on 7-11 shooting for the torrid-shooting Wiildcats, who shot 61.9 percent for the game and 50 percent behind the arc. In the first half, Richfield shot 75 percent (15-20) from the field and 70 percent from range. In defeat, Brax Jensen had 12 points and 8 assists for the Spartans. Emery and Manti will play for third and fourth place Saturday at 3:00 pm. OGDEN, Utah-Brinley Cornell amassed 13 points and 9 rebounds and Sidney McDonald also posted 14 points as Kanab stunned North Summit 58-49 in overtime Friday in the 2-A girls semifinals at the Dee Events Center on the campus of Weber State University. Kennady McQueen netted 20 points and 8 rebounds in the loss for the Braves. Kanab next plays Beaver for a 2-A state title Saturday at 5:00 pm. RICHFIELD, Utah-South Sevier went on a 22-7 run in the 4th Quarter to rout Providence Hall 55-41 Friday in the 3-A boys consolation bracket at the Sevier Valley Center. Tyson Chisholm posted 14 points and 8 rebounds and Peydon Wood had 17 points on 6-9 shooting for the Rams. In defeat, Marcus Sherwood had 13 points and 9 rebounds on 5-10 shooting for the Patriots. South Sevier will play for 5th-6th place Saturday at 11:40 am in the consolation bracket. 2-A Semifinals @ Weber State 2-A Girls Consolation @ Weber State OGDEN, Utah-Sydnee Gillins led the way with 23 points and the Beaver Beavers smacked Enterprise 62-44 in the 2-A girls semifinals Friday at the Dee Events Center. Ronnie Robinson posted yet another double-double, netting 18 points and 11 rebounds in the loss for the Wolves. RICHFIELD, Utah-Ashlee Edwards made a layup in the closing seconds and Grantsville came up with the key defensive stop on the other end to down Richfield 40-39 Friday in the 3-A girls state semifinals at the Sevier Valley Center. Hannah Butler’s 13 points and 7 rebounds led Grantsville in the win. Alexa Lord posted 11 points and 6 rebounds in the loss for the Wildcats. Richfield will play for third and fourth place Saturday at 1:20 pm against Juab. Grantsville plays for a state title at 5:00 pm Saturday against Emery. RICHFIELD, Utah-Kacelyn Toomer posted 13 points and 6 rebounds and the Emery Spartans downed Juab 59-30 Friday to advance to the 3-A state girls championship game at the Sevier Valley Center Saturday. Tatum Hyatt had 7 points in defeat for the Wasps. 3-A State Semifinals @ SVC OGDEN, Utah-Porter Wood amassed 19 points and 14 rebounds as the Parowan Rams routed Kanab 51-27 at the Dee Events Center at Weber State University. Derek Houston had 8 points in the loss for the Cowboys. Parowan next meets Layton Christian Saturday at 7:00 pm for the 2-A championship game. Kanab will face Rowland Hall for third-fourth place at 3:00 pm. FacebookTwitterLinkedInEmailBoys Basketball Brad James 3-A Consolation Bracket @ SVC 2-A Consolation Bracket @ Weber State 3-A Semifinals @ SVC OGDEN, Utah-Ryan Holt posted 29 points and 9 rebounds and Enterprise downed Beaver 49-47 Friday in the 2-A boys consolation bracket at the Dee Events Center. Ky Brown had 19 points and 12 rebounds in the loss for the Beavers. February 22, 2019 /Sports News – Local Prep Sports Roundup: 2/22 OGDEN, Utah-Megan Wade posted 21 points and 10 rebounds as the Millard Eagles routed Wasatch Academy 66-46 Friday in the 2-A girls consolation bracket at Dee Events Center. Duda Raimundo had 21 points in the loss for the Tigers. Millard plays Duchesne Saturday at 10:00 am for 5th-6th place in a battle of the Eagles. Girls Basketball Written by 3-A Consolation Bracket @ SVClast_img read more

Scoreboard roundup — 3/20/19

first_img Beau Lund Written by FacebookTwitterLinkedInEmailiStock(NEW YORK) — Here are the scores from Wednesday’s sports events:NCAA MEN’S BASKETBALLFirst FourEASTN. Dakota St. 78, NC Central 74WESTArizona St. 74, St. John’s 65NIT TOURNAMENTNorfolk St. 80, Alabama 79Xavier 78, Toledo 64Harvard 71, Georgetown 68Wichita St. 76, Furman 70TCU 82, Sam Houston St. 69Nebraska 80, Butler 76CIT TOURNAMENTGreen Bay 102, ETSU 94Presbyterian 73, Seattle 68OT Texas Southern 95, New Orleans 89Rio Grande 74, Grambling St. 73CBI TOURNAMENTDePaul 100, Cent. Michigan 86Brown 83, UAB 78Coastal Carolina 81, Howard 72OT South Florida 82, Stony Brook 79Longwood 90, Southern Miss. 68West Virginia 77, Grand Canyon 63Loyola Marymount 56, California Baptist 55MAJOR LEAGUE BASEBALLINTERLEAGUEDetroit 3, Philadelphia 1Pittsburgh 6, Minnesota 5Atlanta 8, Toronto 7Arizona 11, Chi White Sox 2Cincinnati 6, Texas 1Kansas City 8, Colorado 7San Francisco 13, Cleveland 0AMERICAN LEAGUESeattle 9, Oakland 7Houston 2, NY Yankees 1Boston 6, Baltimore 4Cleveland 4, LA Angels 2NATIONAL LEAGUEMiami 6, St. Louis 0Milwaukee 10, San Diego 7LA Dodgers 4, Chi Cubs 4NATIONAL BASKETBALL ASSOCIATIONPhiladelphia 118, Boston 115Orlando 119, New Orleans 96Cleveland 107, Milwaukee 102Utah 137, NY Knicks 116OT Memphis 126, Houston 125OT Chicago 126, Washington 120Miami 110, San Antonio 105OT Toronto 123, Oklahoma City 114Portland 126, Dallas 118NATIONAL HOCKEY LEAGUEToronto 4, Buffalo 2OT Tampa Bay 5, Washington 4Vancouver 7, Ottawa 4Winnipeg 3, Anaheim 0Copyright © 2019, ABC Radio. All rights reserved.center_img March 21, 2019 /Sports News – National Scoreboard roundup — 3/20/19last_img read more