Is magnetospheric line radiation man-made?

first_imgMagnetospheric line radiation (MLR) events are relatively narrowband VLF signals (∼30 Hz) that sometimes drift in frequency and that have been observed in both ground-based and satellite data sets. We present the result of a survey undertaken on the basis of measurements made of MLR events observed at Halley station, Antarctica (75°35’S, 26°33’W, L≈4.3) during June, July, September, and December 1995, specifically to examine whether there is a link between MLR and power line harmonic radiation (PLHR). We find that (1) the diurnal variation of MLR occurrence at Halley does not resemble the expected load pattern in the industrialized conjugate hemisphere; (2) MLR does not show the pronounced east-west asymmetry in the distribution of arrival directions which would be the case if it was linked to North American electrical load; (3) MLR does not show an immediate association with geomagnetic activity, as would be expected from increases in PLHR levels produced by geomagnetically-induced currents saturating transformers; and (4) there is no evidence of a Sunday, weekend, or other 7-day cycle in the occurrence of MLR. Taken together these results strongly suggest that MLR is a natural VLF emission and is not primarily caused by PLHR. In addition, Halley data have been examined to determine whether the intensity of all types of VLF emissions are influenced by PLHR. We find that (1) there is no significant difference between weekdays and weekends over the frequency range 0.5–9.3 kHz and (2) there is no consistent change in wave intensity that is observed around any of the major North American holiday periods. It is concluded that PLHR is not a significant influence on geospace as viewed from Halley.last_img read more

Significance of lightning-generated whistlers to inner radiation belt electron lifetimes

first_imgThe behavior of high-energy electrons trapped in the Earth’s Van Allen radiation belts has been extensively studied, through both experimental and theoretical techniques. While the evidence for whistler induced electron precipitation (WEP) from the radiation belts is overwhelming, and the mechanisms behind WEP are well understood, the overall significance of WEP on radiation belt loss rates has not been clear. In this paper we investigate the L-shell variation and significance of WEP-driven loss of Van Allen belt electrons by combining in situ measurements of electron precipitation, local WEP rates determined from Trimpi perturbations, and global lightning distributions. Our modeling suggests that long-term WEP driven losses are more significant than all other inner radiation belt loss processes for electron kinetic energies in the range similar to50-150 keV in the L-shell range L=2-2.4. These calculated lifetimes are comparable to the observed decay rates of artificially injected high-energy electrons. The upper energy limit of the WEP significance range increases with decreasing L to similar to225 keV at L=2. For electron energies above this range manmade VLF transmitters and plasmaspheric hiss should dominate over all other loss processes. However, as our lifetimes are based on rather conservative parameter estimates, these conclusions should represent the lower bounds for the energy ranges over which WEP losses are significant. For lower L-shells the coupling of lightning activity to the production of WEP events rapidly decreases, such that by Lsimilar to1.7 WEP will be unimportant in the overall loss processes.last_img read more

Fractal reconnection structures on the magnetopause

first_imgSimple laminar flow models of the magnetosheath plasma lead to predictions of large-scale reconnection structures on the dayside magnetopause. There is observational evidence from the ionosphere that such structures exist. However, in situ observations of the magnetosheath plasma near the magnetopause indicate that the fluid is highly disordered, with the magnetic field orientation in particular being extremely noisy. This raises the question of how coherent large-scale reconnection structures can be created and persist. This paper shows that, if the apparent noise in the magnetosheath field has the characteristics of fractal turbulence, large-scale structures can persist even when the apparent noise levels in the draped magnetic field are very large. Furthermore, the common observation of reconnection transients is naturally explained by this model.last_img read more

Composition of wax esters is linked to diapause behavior of Calanus finmarchicus in a sea loch environment

first_imgWe studied the seasonal lipid dynamics of Calanus finmarchicus from Loch Etive, a semi-enclosed fjordicenvironment on the west coast of Scotland, in relation to the diapause behavior of this species. Levels of total lipidand triacylglycerol in individual copepodid stage V (CVs) exhibited clear seasonal trends, with highest levels inJune and progressively decreasing through late summer to winter. Wax esters in CVs were more variable, butfollowed a similar pattern. An index of the level of unsaturation of wax esters, effectively an indicator of the levelsof polyunsaturated fatty acids in the wax ester reserves, were highest in midsummer and declined progressivelythrough autumn and winter. Fatty acid analysis of total lipid in the CVs confirmed that the amounts ofpolyunsaturated fatty acids in the wax esters decreased, while amounts of saturated and monounsaturated fattyacids remained comparatively stable. Polyunsaturated wax esters are selectively catabolized by C. finmarchicusduring diapause. Previous studies have linked unsaturation of wax esters in calanoid copepods to the initiation ofdiapause and buoyancy control, and we hypothesize that selective catabolism of polyunsaturated wax esters islinked to the processes of diapause termination and ascent to surface waters.last_img read more

DNA metabarcoding uncovers fungal diversity in soils of protected and non-protected areas on Deception Island, Antarctica

first_imgWe assessed soil fungal diversity at two sites on Deception Island, South Shetland Islands, Antarctica using DNA metabarcoding analysis. The first site was a relatively undisturbed area, and the second was much more heavily impacted by research and tourism. We detected 346 fungal amplicon sequence variants dominated by the phyla Ascomycota, Basidiomycota, Mortierellomycota and Chytridiomycota. We also detected taxa belonging to the rare phyla Mucoromycota and Rozellomycota, which have been difficult to detect in Antarctica by traditional isolation methods. Cladosporium sp., Pseudogymnoascus roseus, Leotiomycetes sp. 2, Penicillium sp., Mortierella sp. 1, Mortierella sp. 2, Pseudogymnoascus appendiculatus and Pseudogymnoascus sp. were the most dominant fungi. In addition, 440,153 of the total of 1,214,875 reads detected could be classified only at the level of Fungi. In both sampling areas the DNA of opportunistic, phytopathogenic and symbiotic fungi were detected, which might have been introduced by human activities, transported by birds or wind, and/or represent resident fungi not previously reported from Antarctica. Further long-term studies are required to elucidate how biological colonization in the island may be affected by climatic changes and/or other anthropogenic influences.last_img read more

USU’s Dominik Eberle Named 2nd Team Preseason All-American By Athlon

first_img Written by FacebookTwitterLinkedInEmailLOGAN, Utah-Utah State junior placekicker Dominik Eberle has been named as a second-team preseason All-American by Athlon Sports per a Tuesday announcement.Eberle is one of only three Mountain West Conference players to be named an Athlon Sports preseason All-American as Wyoming safety Andrew Wingard was also named to the second team and Boise State punt returner Avery Williams made the third team.Eberle is a 6’2″ 190-pound kicker from Nuremberg, Germany, by way of Redondo Union High School of Redondo Beach, Calif.Last season, Eberle earned third-team All-American honors from college football expert Phil Steele’s magazine and honorable mention All-American honors from SB Nation as the Aggies’ placekicker in all 13 games as a sophomore in 2017.Eberle also became a finalist for the Lou Groza award, which is annually given to the best kicker in college football.He was a first-team All-Mountain West kicker after making all 47 PAT’s he attempted on the season and was 18-24 (75 percent) on field goal attempts.In a 61-10 win over San Jose State last September 23, Eberle set a single-game school record for points scored by a kicker with 19. He went 4-4 on field goals and 7-7 on PAT’s in that rout of the Spartans.The 19 points are also the second-most scored by a kicker in a game in Mountain West conference history June 19, 2018 /Sports News – Local USU’s Dominik Eberle Named 2nd Team Preseason All-American By Athlon Brad James Tags: Andrew Wingard/Avery Williams/Dominik Eberle/Mountain West Conference/USU Footballlast_img read more

Salt Lake City, Denver Finalists For 2030 Winter Games

first_imgNovember 13, 2018 /Sports News – Local Salt Lake City, Denver Finalists For 2030 Winter Games Tags: Salt Lake City 2030 Olympics Robert Lovell FacebookTwitterLinkedInEmail(Undated)  —  The Reno-Tahoe area is declining to bid for a future Winter Olympics, leaving Salt Lake City and Denver as the two American cities in the running the for the 2030 Winter Games bid.The US Olympic Committee is expected to choose between the two cities by the end of the year for the right to be a bid city.Salt Lake City last hosted the Winter Olympics in 2002. Written bylast_img read more

Masters changes Sunday tee times ahead of weather

first_img Beau Lund Written by FacebookTwitterLinkedInEmailKevin C. Cox/Getty Images(AUGUSTA, Ga.) —  The Masters final round tee times have been adjusted due to potential severe weather Sunday afternoon.Players will be grouped in threesomes with the first tee time scheduled to begin at 7:30 a.m ET off the No. 1 and No. 10 holes.Leader Francesco Molinari (-13) will be paired with Tiger Woods (-11) and Tony Finau (-11). They will tee off at 9:20 a.m ET.“The safety of everyone on our grounds is paramount,” said Fred Ridley, Chairman of Augusta National Golf Club and the Masters Tournament. “We also believe the earlier start will give us the best opportunity to complete the Masters on Sunday. This decision should benefit everyone – the players, our patrons and our fans watching around the world. Given the competitiveness and drama of this year’s Tournament, we look forward to an exciting conclusion tomorrow.”Copyright © 2019, ABC Radio. All rights reserved.center_img April 13, 2019 /Sports News – National Masters changes Sunday tee times ahead of weatherlast_img read more

UVU Men’s Basketball’s Brandon Averett Named 2nd-Team All-WAC Wednesday

first_img FacebookTwitterLinkedInEmailDENVER-Wednesday, Utah Valley men’s basketball transfer, guard Brandon Averett was named to the Western Athletic Conference’s all-preseason second team as the conference’s men’s basketball media day commenced.The event, hosted by the Crowne Plaza Denver International Airport Convention Center, also saw the conference’s media and coaches pick the Wolverines to finish sixth in the WAC.Averette is a junior who transferred from Big 12 power Oklahoma State. During his freshman and sophomore seasons with the Cowboys, Averette played in 69 games, most notably in the 2017-18 season.That season, the native of Richardson, Texas averaged 19.9 minutes, 6.3 points, 2.9 assists, 1.8 rebounds and 0.6 steals per game.Perennial favorite New Mexico State was slated to win the conference title by both coaches and media.The coaches poll picked Grand Canyon second, Seattle U. third, Texas-Rio Grande Valley fourth, California Baptist fifth, Cal State Bakersfield tied for sixth with the Wolverines, Kansas City eighth and Chicago State ninth.The media poll saw Grand Canyon finishing second, with Seattle U. in third place and Texas-Rio Grande Valley in fourth place. California Baptist was slated to finish fifth, Cal State Bakersfield in seventh and Kansas City and Chicago State rounding things out in eighth and ninth place respectively.California Baptist junior guard Milan Acquaah was selected as the preseason player of the year in both polls.The native of Bakersfield, Calif. averaged 19 points and 5 rebounds per game while shooting 85 percent at the foul line on the season for the Lancers in 2018-19. Written by Brad James Tags: Brandon Averett/Cal State Bakersfield/California Baptist/Grand Canyon/Milan Acquaah/Oklahoma State/Richardson/Seattle U./Texas/Texas-Rio Grande Valley/UVU Men’s Basketball/WAC October 9, 2019 /Sports News – Local UVU Men’s Basketball’s Brandon Averett Named 2nd-Team All-WAC Wednesdaylast_img read more

Scoreboard roundup — 8/26/20

first_img Written by FacebookTwitterLinkedInEmailiStockBy ABC News(NEW YORK) — Here are the scores from Wednesday’s sports events: MAJOR LEAGUE BASEBALLINTERLEAGUEChi White Sox 10, Pittsburgh 3Atlanta 5, NY Yankees 1Atlanta 2, NY Yankees 1Detroit 7, Chi Cubs 6St. Louis 6 Kansas City 5Seattle at San Diego (Postponed)AMERICAN LEAGUEToronto 9, Boston 1Tampa Bay 4, Baltimore 3Cleveland 6, Minnesota 3Oakland 3, Texas 1LA Angels at Houston (Postponed)NATIONAL LEAGUEPhiladelphia 3, Washington 2NY Mets 5, Miami 4Colorado 8, Arizona 7LA Dodgers at San Francisco (Postponed)Cincinnati at Milwaukee (Postponed)NATIONAL BASKETBALL ASSOCIATION PLAYOFFSMiami at Indiana (Unnecessary) (Miami wins 4-0)Orlando at Milwaukee (Postponed) (Milwaukee leads 3-1)Oklahoma City Houston (Postponed) (Series tied 2-2)Portland at LA Lakers (Postponed) (LA Leads 3-1)NATIONAL HOCKEY LEAGUE PLAYOFFSPhiladelphia 4, NY Islanders 3 (OT) (Series Tied 1-1)Tampa Bay 7, Boston 1 (Tampa Bay leads 2-1)Colorado 6, Dallas 4 (Dallas leads 2-1)WOMEN’S NATIONAL BASKETBALL ASSOCIATIONWashington at Atlanta (Postponed)Los Angeles at Minnesota (Postponed)Connecticut at Phoenix (Postponed)MAJOR LEAGUE SOCCEROrlando City 3, Nashville 1Atlanta at Montreal (Canceled)Atlanta at Miami (Canceled)Colorado at FC Dallas (Canceled)Los Angeles FC at Real Salt Lake (Canceled)Vancouver at Los Angeles FC (Canceled)Portland at San Jose (Canceled)Seattle at LA Galaxy (Canceled)Copyright © 2020, ABC Audio. All rights reserved. Beau Lundcenter_img August 27, 2020 /Sports News – National Scoreboard roundup — 8/26/20last_img read more