Combination of ionosonde and riometer data for absorption measurements

first_imgA method is described for combining ionosonde and riometer data which overcomes limitations in both techniques for the measurement of normal absorption in the lower ionosphere. The usefulness of these techniques is thereby considerably increased.last_img

A large-scale ionospheric depletion by intense radio wave heating

first_imgA large (100 km N/S), stable, smoothly‐structured and significant depletion (15% in number density) of the daytime Tromsø F‐region was produced inadvertently during a Heater polarisation and beam‐forming procedure. We show that the depletion coincided with the passage of an atmospheric gravity wave of natural origin which served as a large‐scale ‘seed‘ depletion for the self‐focussing instabilitylast_img

Simultaneous observations of magnetopause flux transfer events and of their associated signatures at ionospheric altitudes

first_imgAn extensive variety of instruments, including Geotail, DMSP F11, SuperDARN, and IMP-8, were monitoring the dayside magnetosphere and ionosphere between 14:00 and 18:00 UT on 18 January 1999. The location of the instruments provided an excellent opportunity to study in detail the direct coupling between the solar wind, the magnetosphere, and the ionosphere. Flux transfer events were observed by Geotail near the magnetopause in the dawn side magnetosheath at about 4 magnetic local time during exclusively northward interplanetary magnetic field conditions. Excellent coverage of the entire dayside high-latitude ionosphere was achieved by the Northern Hemisphere SuperDARN radars. On the large scale, temporally and spatially, the dayside magnetosphere convection remained directly driven by the interplanetary magnetic field, despite the highly variable interplanetary magnetic field conditions, including long periods of northward field. The SuperDARN radars in the dawn sector also measured small-scale temporally varying convection velocities, which are indicative of flux transfer event activity, in the vicinity of the magnetic footprint of Geotail. DMSP F11 in the Southern Hemisphere measured typical cusp precipitation simultaneously with and magnetically conjugate to a single flux transfer event signature detected by Geotail. A study of the characteristics of the DMSP ion spectrogram revealed that the source plasma from the reconnection site originated downstream of the subsolar point. Detailed analyses of locally optimised coordinate Systems for individual flux transfer events at Geotail are consistent with a series of flux tubes protruding from the magnetopause, and originating from a high-latitude reconnection site in the Southern Hemisphere. This high-latitude reconnection site agrees with plasma injected away from the subsolar point. This is the first simultaneous and independent determination from ionospheric and space-based data of the location of magnetic reconnection.last_img read more

Utility of geolocating light loggers to indicate at-sea movements in sea turtles

first_imgAs marine turtles traverse entire ocean basins, a number of techniques have been developed to gather information on their movements at sea. These range from basic methods, such as mark and recapture using flipper tags, to more technically advanced, expensive approaches, such as satellite tracking. Here we report the first published use of geolocation by light, using global location sensing (GLS) units, to estimate the locations of marine turtles in the Mediterranean. We attached units to 9 green Chelonia mydas and 3 loggerhead Caretta caretta turtles which had nested in Cyprus in previous years. One individual of each species was also fitted with a satellite transmitter for comparison. GLS units were retrieved on subsequent visits made by instrumented turtles during the same nesting season. In total, 28 GLS units were recovered from 12 individuals. The mean great-circle distance between the mean daily position calculated from satellite tracking and the corresponding mean light-based geolocation over the same time period was 50.3 km for green turtles and 57.6 km for loggerhead turtles. We suggest that GLS technology offers potential utility for identifying large-scale movements, migratory pathways, and over-wintering or foraging sites of adult female marine turtles.last_img read more

Wintertime ocean conditions over the southern Weddell Sea continental shelf, Antarctica

first_imgDuring the austral winter of 2007 a Weddell Seal tagged with a miniaturized conductivity-temperature-depth (CTD) instrument travelled over the central southern Weddell Sea continental shelf. The instrument yielded 750 CTD profiles, 250 of them to the sea floor. The data show a full depth flow of water onto the shelf via a sill at the shelf break (74°S 44°W). The warmth from the core of the flow was able to maintain the surface mixed layer above the freezing point, resulting in a band of reduced ice-production. An estimate of the on-shelf flux suggests that this flow accounts for most of the estimated 3 Sv of water draining from the southern Weddell Sea continental shelf.last_img

Trophic position of deep-sea fish – assessment through fatty acid and stable isotope analyses

To investigate the trophic ecology of two of the dominant families of deep-sea fish (Macrouridae and Moridae) fatty acid and stable isotope analyses were applied to liver and muscle samples of five abundant species from the NE Atlantic. In conjunction with stomach content data these methods made it possible to identify differences in feeding strategies between the five study species as well as variation in feeding in relation to increasing depth and body size. Biomarkers identified strong similarities between Coryphaenoides armatus and Antimora rostrata though differences were found associating C armatus more with the benthic food web whereas A. rostrata showed stronger links to the pelagic food web. While Lepidion eques was classified as a species linking benthic and benthopelagic food webs, both fatty acid and stable isotope data suggested that Coryphaenoides guentheri fed on an exclusively benthic diet. Coryphaenoides rupestris on the other hand were largely dependent on a copepod-based food web. Ontogenetic changes in feeding were found for both A. rostrato and C armatus with the indication of a switch from active predation to scavenging occurring with increasing body size. Biomarkers also reflected the seasonal influx from the photic zone though changes were species-specific and probably reflected the variation in prey availability and abundance in response to these inputs. Our findings have thus demonstrated that the combined use of these biomarkers can elucidate trophic specialisations in situations where conventional methods alone previously provided insufficient data. read more

Synchronous volcanic eruptions and abrupt climate change ∼17.7 ka plausibly linked by stratospheric ozone depletion

first_imgGlacial-state greenhouse gas concentrations and Southern Hemisphere climate conditions persisted until ∼17.7 ka, when a nearly synchronous acceleration in deglaciation was recorded in paleoclimate proxies in large parts of the Southern Hemisphere, with many changes ascribed to a sudden poleward shift in the Southern Hemisphere westerlies and subsequent climate impacts. We used high-resolution chemical measurements in the West Antarctic Ice Sheet Divide, Byrd, and other ice cores to document a unique, ∼192-y series of halogen-rich volcanic eruptions exactly at the start of accelerated deglaciation, with tephra identifying the nearby Mount Takahe volcano as the source. Extensive fallout from these massive eruptions has been found >2,800 km from Mount Takahe. Sulfur isotope anomalies and marked decreases in ice core bromine consistent with increased surface UV radiation indicate that the eruptions led to stratospheric ozone depletion. Rather than a highly improbable coincidence, circulation and climate changes extending from the Antarctic Peninsula to the subtropics—similar to those associated with modern stratospheric ozone depletion over Antarctica—plausibly link the Mount Takahe eruptions to the onset of accelerated Southern Hemisphere deglaciation ∼17.7 ka.last_img read more

Scoreboard roundup — 3/5/18

first_img Beau Lund March 4, 2018 /Sports News – National Scoreboard roundup — 3/5/18 Written bycenter_img FacebookTwitterLinkedInEmailiStock/Thinkstock(NEW YORK) — Here are the scores from yesterday’s sports events:  NATIONAL BASKETBALL ASSOCIATIONAtlanta 113, Phoenix 112Indiana 98, Washington 95Toronto 103, Charlotte 98New Orleans 126, Dallas 109Milwaukee 118, Philadelphia 110Sacramento 102, N.Y. Knicks 99L.A. Clippers 123, Brooklyn 120NATIONAL HOCKEY LEAGUENashville 4, Colorado 3; OT Florida 4, Philadelphia 1Anaheim 6, Chicago 3Vegas 3, New Jersey 2Minnesota 4, Detroit  1Winnipeg 3, Carolina 2Columbus 4, San Jose 2TOP-25 COLLEGE BASKETBALL(15) Michigan 75, (8) Purdue 66(10) Cincinnati 62, (11) Wichita St. 61(22) Saint Mary’s (Cal) 69, Pepperdine 66(25) Houston 81, UConn 71Copyright © 2018, ABC Radio. All rights reserved.last_img read more

Woman claims ex-NBA star raped her during her sophomore year at Duke

first_imgFebruary 12, 2019 /Sports News – National Woman claims ex-NBA star raped her during her sophomore year at Duke Written by Beau Lundcenter_img FacebookTwitterLinkedInEmailStreeter Lecka/Getty Images(NEW YORK) — The same woman who has accused Virginia Lieutenant Governor Justin Fairfax of sexual assault says that former N.B.A player Corey Maggette raped her 20 years ago when the two were both students at Duke University.Meredith Watson, the second woman to come forward with claims of sexual assault against Fairfax, says that she reported the alleged incident involving Maggette to school officials, who she says did not act on the information.An attorney for Watson, Nancy Erika Smith, confirmed the claim to ABC News in a statement. The incident and claim were first reported by the New York Times.ABC News has reached out to representatives for Maggette, who attended Duke for one year and played in the N.B.A for 14 years, but have not yet received a response.In a statement given to the New York Times, Maggette denied Watson’s claim.“It has only been through media accounts and a statement from Meredith Watson’s lawyer that I first learned or heard of anything about these sexual assault allegations,” Maggette wrote. “I have never sexually assaulted anyone in my life and I completely and categorically deny any such charge.”Fairfax has also denied the claims made against him by Watson.“I deny this latest unsubstantiated allegation. It is demonstrably false. I have never forced myself on anyone ever,” Fairfax wrote in a statement released last week after Watson’s accusation became public.Whitney Burak, a spokesperson for Fox Sports, where Maggette is now a basketball commentator, issued a statement to ABC News responding to the claims against Maggette.“FOX Sports takes allegations of misconduct seriously, and we are looking into the matter. We have no further comment at this time,” Burak said.Michael Schoenfeld, vice president for public affairs and government relations at Duke University issued a statement on Monday saying, “We are in the process of gathering information to determine what policies and procedures were in place during the time period in which these events are alleged to have occurred and whether they were activated and followed. We are not able to provide further information or comment on any individual at this time.”In Facebook messages obtained by ABC News, Watson communicated with a friend, whose identity has been redacted, about the alleged incidents involving Fairfax and Maggette. The Facebook Messenger communications are dated March 19, 2017.Watson sent a link to an article about Fairfax’s 2017 campaign for lieutenant governor of Virginia to the friend, with an accompanying message that read: “This is absolutely disgusting! This dude raped me.”When the friend questioned why she didn’t report it, she responded: “You know I didn’t report it after how the university responded when I reported Corey Maggette…but he told me he [Fairfax] did it on purpose bcuz of what Corey did and bcuz he knew I’d be too scared to do anything about it.”ABC News also reached out to R. Stanton Jones, a childhood friend of Watson’s, who confirmed that Watson told him about the alleged rape involving Maggette in the summer of 2001 when the two were home for the summer from college.While this is the first accusation to surface against Maggette, Fairfax was also accused of sexual assault by another woman, Vanessa Tyson, an associate professor of politics at Scripps College in California.Tyson, who is scheduled to speak tonight at sexual violence symposium at Stanford University on Tuesday evening, says that Fairfax sexually assaulted her in 2004 when the two of them attended the Democratic National Convention in Boston.Fairfax says the encounter was consensual.Copyright © 2019, ABC Radio. All rights reserved.last_img read more

Tailgate Guys Partner With BYU To Provide Premium Game-Day Football Hospitality

first_img Tags: BYU Athletics/BYU Football/LaVell Edwards Stadium/Tailgate Guys FacebookTwitterLinkedInEmailPROVO, Utah-Tuesday, BYU Athletics announced a partnership with Tailgate Guys, the nation’s leader in premium tailgate and event services, as confirmed during BYU football media day proceedings.This partnership will allow BYU football fans and alumni to save time and simplify the game-day experience at LaVell Edwards Stadium.Tailgate Guys provides premium locations, tents, chairs, tables, coolers and other tailgating essentials.These “turnkey” tailgate packages can serve small events and large gatherings equally well.Each package consists of setup and breakdown, game-day bellhop services, high peak tents, DISH media packages and local catering options. June 18, 2019 /Sports News – Local Tailgate Guys Partner With BYU To Provide Premium Game-Day Football Hospitality Written by Brad Jameslast_img read more