Diurnal and seasonal variation in oral glucose tolerance: Studies in the Antarctic

first_imgOral glucose tolerance tests were performed in 12 young men in the Antarctic. Tests were done in the morning and afternoon at three monthly intervals (March, June, September, December). The characteristic diurnal variation in glucose tolerance persisted throughout the year, but was greater in the warmer months (March and December). There were significant seasonal differences in glucose tolerance; blood glucose values were lowest, both morning and afternoon, in December (midsummer). In one pair of tests performed during a reversal of normal sleep/activity pattern, the direction of the normal diurnal variation of glucose tolerance was also reversed.last_img

Quasilongitudinal approximation for whistler-mode waves in the magnetospheric plasma

first_imgThe range of applicability of an improved quasilongitudinal approximation for whistler-mode waves in the equatorial magnetosphere (4 ≲ L ≲ 6.6) is specified based on the direct comparison between numerical solutions of the hot electromagnetic dispersion equation with the corresponding analytical quasilongitudinal solutions. It is pointed out that this approximation can be used at frequencies ω less than but not close to the electron gyrofrequencyΩ (ω ≲ 0.6 Ω)and wave normal angles θ less than but not close to the resonance cone angle θR. Atω = 0.8 Ωthe analytical results deviate considerably from numerical ones due to the strong damping of the waves, and so the quasilongitudinal solution becomes no longer valid.last_img

Campanian-Maastrichtian (Cretaceous) stratigraphy of the James Ross Island area, Antarctica

first_imgOne of the most important outcrops of uppermost Cretaceous (Campanian–Maastrichtian) sedimentary rocks in the southern high latitudes occurs within the James Ross Island group, northeastern Antarctic Peninsula. These rocks comprise a 1500–2000 m thick sequence of predominantly shallow marine clastic sediments that were deposited within a retro-arc basin. They are virtually undeformed and have yielded prolific invertebrate and vertebrate faunas, and a wide range of plant taxa. Campanian–Maastrichtian strata are contained within two component formations of the Upper Cretaceous-lower Tertiary Marambio Group. The lower Santa Marta Formation is approximately 1100m thick and has three constituent members. Ammonites within the Santa Marta Formation indicate an early to late Campanian age assignment. Dinoflagellates suggest that the lower levels of the formation may range into the Santonian Stage. In the northern James Ross Island to Vega Island region there is a conformable transition into the overlying López de Bertodano Formation. Here the basal Cape Lamb Member is unconformably overlain by the Sandwich Bluff Member. Although there are some lithological and fauna1 discrepancies, which are attributed to marked lateral facies changes across the basin, it is believed that the Cape Lamb Member can be correlated with the lower to middle regions of the 1200 m thick sequence of undifferentiated López de Bertodano Formation lithologies exposed on Seymour Island. Molluscan data indicate a late Campanian–Palaeocene age range for this upper formation. Dinoflagellates again suggest that the lowest beds may be slightly older. The correlation presented provides the basis for a formal subdivision of the Campanian and Maastrichtian stages in the southern high latitudes. It has also revealed two major basin shallowing events (in the late Campanian–early Maastrichtian and latest Maastrichtian, respectively) and the existence of a major fault/fault zone across southeastern James Ross Island. The improved temporal framework will aid late Cretaceous palaeoclimatic and palaeobiological studies in Antarctica.last_img read more

Genetic structure and history of populations of the deep-sea fish Helicolenus dactylopterus (Delaroche, 1809) inferred from mtDNA sequence analysis

first_imgHelicolenus dactylopterus is an Atlantic benthopelagic fish species inhabiting high-energy habitats on continental slopes, seamounts and islands. Partial sequences of the mitochondrial control region (D-loop) and cytochrome b (cyt b) were used to test the hypothesis that H. dactylopterus disperses between continental margin, island and seamount habitats on intraregional, regional and oceanic scales in the North Atlantic. Individuals were collected from five different geographical areas: Azores, Madeira, Portugal (Peniche), Cape Verde and the northwest Atlantic. D-loop (415 bp) and cyt b (423 bp) regions were partially sequenced for 208 and 212 individuals, respectively. Analysis of variation among mitochondrial DNA sequences based on pairwise F-statistics and AMOVA demonstrated marked genetic differentiation between populations in different geographical regions specifically the Mid-Atlantic Ridge (Azores)/northeast Atlantic (Portugal, Madeira) compared to populations around the Cape Verde Islands and in the northwest Atlantic. Some evidence of intraregional genetic differentiation between populations was found. Minimum-spanning network analysis revealed star-shaped patterns suggesting that populations had undergone expansion following bottlenecks and/or they have been colonized by jump dispersal events across large geographical distances along pathways of major ocean currents. Mismatch distribution analysis indicated that Azores and northwest Atlantic populations fitted a model of historical population expansion following a bottleneck/founder event estimated to be between 0.64 and 1.2 million years ago (Ma).last_img read more

The structure, biological activity and biogeochemistry of cryoconite aggregates upon an Arctic valley glacier: Longyearbreen, Svalbard

first_imgGlacier surfaces support unique microbial food webs dominated by organic and inorganic debris called ‘cryoconite’. Observations from Longyearbreen, Spitsbergen, show how these aggregate particles can develop an internal structure following the cementation of mineral grains (mostly quartz and dolomite) by filamentous microorganisms. Measurements of carbon and dissolved O2 show that these microorganisms, mostly cyanobacteria, promote significant rates of photosynthesis (average 17 μgC g−1 d−1) which assist aggregate growth by increasing the biomass and producing glue-like extracellular polymeric substances. The primary production takes place not only upon the surface of the aggregates but also just beneath, due to the translucence of the quartz particles. However, since total photosynthesis is matched by respiration (average 19 μgC g−1 d−1), primary production does not contribute directly to cryoconite accumulation upon the glacier surface. The microorganisms therefore influence the surface albedo most by cementing dark particles and organic debris together, rather than simply growing over it. Time-lapse photographs show that cryoconite is likely to reside upon the glacier for years as a result of this aggregation. These observations therefore show that a better understanding of the relationship between supraglacial debris and ablation upon glaciers requires an appreciation of the biological processes that take place during summer.last_img read more

Bayesian analysis of rapid climate change during the last glacial using Greenland δ18O data

first_imgWe present statistical methods to determine climate regimes for the last glacial period using three temperature proxy records from Greenland: measurements of δ18O from the Greenland Ice Sheet Project 2 (GISP2), the Greenland Ice Core Project (GRIP) and the North Greenland Ice Core Project (NGRIP) using different timescales. A Markov Chain Monte Carlo method is presented to infer the number of states in a latent variable model along with their associated parameters. By using Bayesian model comparison methods we find that a model with 3 states is sufficient. These states correspond to a gradual cooling during the Greenland Interstadials, more rapid temperature decrease into Greenland Stadial and to the sudden rebound temperature increase at the onset of Greenland Interstadials. We investigate the recurrence properties of the onset of Greenland Interstadials and find no evidence to reject the null hypothesis of randomly timed events.last_img read more

A review of data on abundance, trends in abundance, habitat use and diet of ice-breeding seals in the Southern Ocean

first_imgThe development of models of marine ecosystems in the Southern Ocean is becoming increasingly important as a means of understanding and managing impacts such as exploitation and climate change. Collating data from disparate sources, and understanding biases or uncertainties inherent in those data, are important first steps for improving ecosystem models. This review focuses on seals that breed in ice habitats of the Southern Ocean (i.e. crabeater seal, Lobodon carcinophaga; Ross seal, Ommatophoca rossii; leopard seal, Hydrurga leptonyx; and Weddell seal, Leptonychotes weddellii). Data on populations (abundance and trends in abundance), distribution and habitat use (movement, key habitat and environmental features) and foraging (diet) are summarised, and potential biases and uncertainties inherent in those data are identified and discussed. Spatial and temporal gaps in knowledge of the populations, habitats and diet of each species are also identified.last_img read more

Justify leads wire to wire at Belmont to win the Triple Crown

first_img Written by FacebookTwitterLinkedInEmailRob Carr/Getty Images(ELMONT, N.Y.) — Justify charged out of the gate and never gave up the lead, powering his way to victory at the Belmont Stakes to become just the 13th horse to win the Triple Crown.The colt was briefly challenged in the final turn, but down the stretch jockey Mike Smith let him use his strength to run away from the field. Gronkowski finished second, 1 3/4 lengths back, and Hofburg was third.Justify’s victory made Bob Baffert just the second trainer to win the Triple Crown twice. He previously won in 2015 with American Pharoah, the colt that ended a 37-year drought.With the win, Justify improved to 6-0 in a career that began in February, making him one of the rare Triple Crown winners not to race as a 2-year-old.Smith, at 52, is the oldest jockey to win the Triple Crown.The Kentucky Derby and Preakness winner went off a 4/5 favorite for the 1 1/2-mile Belmont, the longest and most grueling of the three-race series. He paid $3.60 for the win, $3.50 to place and $2.80 to show.He’d won the first two legs of the Triple Crown on sloppy tracks, charging to a 2 1/2-length victory in the 1 1/4-mile Kentucky Derby on May 5, and then pulling out a a half-length win in the 1 3/16-mile Preakness on May 19. Copyright © 2018, ABC Radio. All rights reserved. June 9, 2018 /Sports News – National Justify leads wire to wire at Belmont to win the Triple Crowncenter_img Beau Lundlast_img read more

Scoreboard roundup — 8/11/18

first_img FacebookTwitterLinkedInEmailiStock/Thinkstock(NEW YORK) — Here are the scores from Saturday’s sports events:INTERLEAGUESt. Louis 8, Kansas City 3AMERICAN LEAGUEBoston 5, Baltimore 0N.Y. Yankees 5, Texas 3Tampa Bay 3, Toronto 1Minnesota 4, Detroit 3Boston 6, Baltimore 4Seattle 3, Houston 2Cleveland 3, Chicago White Sox 1Oakland 7, L.A. Angels 0NATIONAL LEAGUEWashington 9, Chicago Cubs 4Cincinnati 6, Arizona 3Miami 4, N.Y. Mets 3, 11 InningsMilwaukee 4, Atlanta 2Colorado 3, L.A. Dodgers 2Philadelphia 5, San Diego 1Pittsburgh 4, San Francisco 0WOMEN’S NATIONAL BASKETBALL ASSOCIATIONAtlanta 92, Dallas 82Las Vegas 92, Indiana 74NATIONAL FOOTBALL LEAGUE PRESEASONMinnesota 42, Denver 28Arizona 24, L.A. Chargers 17MAJOR LEAGUE SOCCERPhiladelphia 3, New England 2Copyright © 2018, ABC Radio. All rights reserved. Written by August 12, 2018 /Sports News – National Scoreboard roundup — 8/11/18center_img Beau Lundlast_img read more

Sushi or shellfish? Congressmen place bets on the World Series

first_imgOctober 23, 2018 /Sports News – National Sushi or shellfish? Congressmen place bets on the World Series FacebookTwitterLinkedInEmailiStock/Thinkstock(NEW YORK) — Will it be sushi or shellfish?That’s the friendly bet Democratic Reps. Joe Kennedy III of Massachusetts and Adam Schiff of California have placed on the outcome of the World Series as the Boston Red Sox and Los Angeles Dodgers prepare to face-off in Game 1 Tuesday night at Boston’s Fenway Park.Kennedy represents the area surrounding Fenway Park, while Schiff represents the area bordering Dodger Stadium.“It’s been 30 years since the Dodgers won the series, which may not seem like that long to Sox fans, but as a point of reference, it’s almost as long as Joe has been alive,” Schiff joked in a joint statement with Kennedy.The winner of the bet, along with staff from the winner’s office, will be treated to a seafood dinner from the loser’s state: sushi from California or shellfish from Massachusetts.Friendly sports wagers are nothing new in Congress, but in recent years, they’ve shown a flair for theatrics.When the Dodgers lost to the Houston Astros in last year’s series, Rep. Jimmy Gomez, a California Democrat, flew across the country to Los Angeles with a suitcase full of the ingredients for French dip sandwiches after losing his wager. The rabid Dodgers fan who represents downtown Los Angeles used a cart decked out in Dodgers gear to deliver the sandwiches to the office of Texas Rep. Sheila Jackson Lee, a Democrat who represents the area where the Astros’ stadium is located.It has been more than a century since the Dodgers and Red Sox last met in the World Series in 1916 — Boston took the title then, and Kennedy believes history will repeat itself.“Unless Adam has shared some deeply classified information that I can’t access with Dave Roberts, my staff and I will be figuring out why LA insists on eating raw fish in a few weeks,” Kennedy said.Copyright © 2018, ABC Radio. All rights reserved. Written bycenter_img Beau Lundlast_img read more