Why Raman spectroscopy on Mars? – a case of the right tool for the right job

first_imgWe provide a scientific rationale for the astrobiological investigation of Mars. We suggest that, given practical constraints, the most promising locations for the search for former life on Mars are palaeolake craters and the evaporite deposits that may reside within them. We suggest that Raman spectroscopy offers a promising tool for the detection of evidence of former (or extant) biota on Mars. In particular, we highlight the detection of hopanoids as long-lived bacterial cell wall products and photosynthetic pigments as the most promising targets. We further suggest that Raman spectroscopy as a fibre optic-based instrument lends itself to flexible planetary deploymentlast_img

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Freshwater transport at Fimbulisen, Antarctica

The intricate near-circumpolar system of fronts and currents surrounding Antarctica isolates much of Earth’s freshwater from the saline oceans immediately north. The Antarctic Slope Front sustains bathymetrically steered flow at the shelf break, whereas the shallow Coastal Current travels rapidly alongside the ice front. A hydrographic survey of the southeastern Weddell Sea finds these two features to have merged near the narrow (<40 km wide) continental shelf at Fimbulisen. On the prime meridian, its Trolltunga ice tongue overshoots the shelf break northward into this slope current. Observations on either side of the ice tongue demonstrate its retarding effect on the westward-flowing waters it overhangs and its contribution to the poorly understood freshwater budget. From oxygen isotope ratio measurements and referenced geostrophic shears, we find the combined glacial meltwater and sea ice melt transport upstream of Trolltunga at 0.6°E to account for 18.0 ± 5.8 mSv of the total 1.6 ± 0.2 Sv westward transport (Sv = 10^6 m^3 s^−1). In Trolltunga's lee and downstream at 2.8°W, we find this figure to ultimately increase to 23.8 ± 15.5 mSv of a total 2.8 ± 0.4 Sv transport. Each of these sections was impeded by sea ice cover, so these estimates of westward transport are probably lower limits. The westward glacial ice meltwater transport of 10 ± 3 mSv at 2.8°W highlights the role that Fimbulisen plays in preconditioning shelf waters before they reach broad continental shelves in the southwestern Weddell Sea where they transform to bottom waters. read more

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Antarctic Tardigrada: a first step in understanding molecular operational taxonomic units (MOTUs) and biogeography of cryptic meiofauna

first_imgRecent studies have suggested that some resident Antarctic biota are of ancient origin and may have been isolated for millions of years. The phylum Tardigrada, which is part of the Antarctic terrestrial meiofauna, is of particular interest due to an impressive array of biochemical abilities to withstand harsh environmental conditions. Tardigrades are one of the few widespread Antarctic terrestrial animals that have the potential to be used as a model for evolution and biogeography on the Antarctic continent. We isolated 126 individual tardigrades from four geographically isolated soil samples from two remote nunataks in the Sør Rondane Mountains, Dronning Maud Land, Antarctica. We examined genetic variation among individuals utilising three gene regions: cytochrome c oxidase subunit I gene (COI), 18S rDNA (18S), and the wingless (Wg) gene. Comparison of sequences from worldwide and Antarctic tardigrades indicated long-term survival and isolation over glacially dominated periods in ice-free habitats in the Sør Rondane Mountains.last_img read more

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POES satellite observations of EMIC-wave driven relativistic electron precipitation during 1998-2010

first_img[1] Using six Polar Orbiting Environmental Satellites (POES) satellites that have carried the Space Environment Module-2 instrument package, a total of 436,422 individual half-orbits between 1998 and 2010 were inspected by an automatic detection algorithm searching for electromagnetic ion cyclotron (EMIC) driven relativistic electron precipitation (REP). The algorithm searched for one of the key characteristics of EMIC-driven REP, identified as the simultaneity between spikes in the P1 (52 keV differential proton flux channel) and P6 (>800 keV electron channel). In all, 2331 proton precipitation associated REP (PPAREP) events were identified. The majority of events were observed at L-values within the outer radiation belt (3 < L < 7) and were more common in the dusk and night sectors as determined by magnetic local time. The majority of events occurred outside the plasmasphere, at L-values ~1 Re greater than the plasmapause location determined from two different statistical models. The events make up a subset of EMIC-driven proton spikes investigated by Sandanger et al. (2009), and potentially reflect different overall characteristics compared with proton spikes, particularly when comparing their location to that of the plasmapause, i.e., EMIC-driven proton precipitation inside the plasmapause, and potentially EMIC-driven REP outside the plasmapause. There was no clear relationship between the location of plasmaspheric plumes and the locations of the PPAREP events detected. Analysis of the PPAREP event occurrence indicates that high solar wind speed and high geomagnetic activity levels increase the likelihood of an event being detected. The peak PPAREP event occurrence was during the declining phase of solar cycle 23, consistent with the 2003 maximum in the geomagnetic activity index, Ap.last_img read more

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Thick and deformed Antarctic sea ice mapped with autonomous underwater vehicles

first_imgSatellites have documented trends in Antarctic sea-ice extent and its variability for decades, but estimating sea-ice thickness in the Antarctic from remote sensing data remains challenging. In situ observations needed for validation of remote sensing data and sea-ice models are limited; most have been restricted to a few point measurements on selected ice floes, or to visual shipboard estimates. Here we present three-dimensional (3D) floe-scale maps of sea-ice draft for ten floes, compiled from two springtime expeditions by an autonomous underwater vehicle to the near-coastal regions of the Weddell, Bellingshausen, and Wilkes Land sectors of Antarctica. Mean drafts range from 1.4 to 5.5 m, with maxima up to 16 m. We also find that, on average, 76% of the ice volume is deformed ice. Our surveys indicate that the floes are much thicker and more deformed than reported by most drilling and ship-based measurements of Antarctic sea ice. We suggest that thick ice in the near-coastal and interior pack may be under-represented in existing in situ assessments of Antarctic sea ice and hence, on average, Antarctic sea ice may be thicker than previously thought.last_img read more

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Low post-glacial rebound rates in the Weddell Sea due to Late Holocene ice-sheet re-advance

first_imgMany ice-sheet reconstructions assume monotonic Holocene retreat for the West Antarctic Ice Sheet, but an increasing number of glaciological observations infer that some portions of the ice sheet may be readvancing, following retreat behind the present-day margin. A readvance in the Weddell Sea region can reconcile two outstanding problems: (i) the present-day widespread occurrence of seemingly stable ice streams grounded on beds that deepen inland; and (ii) the inability of models of glacial isostatic adjustment to match present-day uplift rates. By combining a suite of ice loading histories that include a readvance with a model of glacial isostatic adjustment we report substantial improvements to predictions of present-day uplift rates, including reconciling one problematic observation of land sinking. We suggest retreat behind present grounding lines occurred when the bed was lower, and isostatic recovery has since led to shallowing, ice sheet re-grounding and readvance. The paradoxical existence of grounding lines in apparently unstable configurations on reverse bed slopes may be resolved by invoking the process of unstable advance, in accordance with our load modelling.last_img read more

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Life in the intertidal: cellular responses, methylation and epigenetics

first_img1.Phenotypic plasticity is essential for the persistence of organisms under changing environmental conditions but the control of the relevant cellular mechanisms including which genes are involved and the regulation of those genes remains unclear. One way to address this issue is to evaluate links between gene expression, methylation and phenotype using transplantation and common garden experiments within genetically homogeneous populations.2.This approach was taken using the Antarctic limpet Nacella concinna. In this species, two distinct phenotypes are associated with the intertidal and subtidal zones. The in situ gene expression and methylation profiles of intertidal and subtidal cohorts were directly compared before and after reciprocal transplantation as well as after a common garden acclimation to aquarium conditions for 9 months.3.Expression profiles showed significant modulation of cellular metabolism to habitat zone with the intertidal profile characterised by transcription modules for antioxidant production, DNA repair and the cytoskeleton reflecting the need to cope with continually fluctuating and stressful conditions including wave action, UV irradiation and desiccation.4.Transplantation had an effect on gene expression. The subtidal animals transplanted to the intertidal zone modified their gene expression patterns towards that of an intertidal profile. In contrast, many of the antioxidant genes were still differentially expressed in the intertidal animals several weeks after transplantation into the relatively benign subtidal zone.5.Furthermore, a core of genes involved in antioxidation was still preferentially expressed in intertidal animals at the end of the common garden experiment. Thus, acclimation in an aquarium tank for 9 months did not completely erase the intertidal gene expression profile.6.Significant methylation differences were measured between intertidal and subtidal animals from the wild and after transplantation, which were reduced on common garden acclimation. This suggests that epigenetic factors play an important role in physiological flexibility associated with environmental niche.last_img read more

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SUU Football Celebrates Kid’s Day To Wrap Up Spring Football

first_img Tags: Big Sky Conference/Demario Warren/North Alabama/Southern Utah Football/Spring Game April 14, 2018 /Sports News – Local SUU Football Celebrates Kid’s Day To Wrap Up Spring Football Brad James FacebookTwitterLinkedInEmailCEDAR CITY, Utah (SUUtbirds.com)-Saturday, the Southern Utah University football team wrapped up spring football with the annual Kid’s day at Eccles Coliseum.“Kid’s day” officially serves as the Thunderbirds’ spring game as the team went head-to-head against kids from the Cedar City area in a number of series. Fans were also invited to participate in several on-field activities.SUU head coach Demario Warren thought things went well citing there were “no turnovers, no penalties, so that’s a good sign.”Warren further stated this event means a lot both to him and his team.Saturday, in one of the classrooms at the America First Events Center, the Thunderbirds’ coaching staff also presented the players with Big Sky Conference championship rings as SUU was the 2017 Big Sky champion, prior to the scrimmage.Warren stated that the Thunderbirds’ next goal is to win the FCS national championship, after having won the Big Sky two times in the past three seasons.With spring football now finished, the Thunderbirds next turn their attention to August 28, when they will host Division I newcomer North Alabama at Eccles Coliseum.SUU season ticket renewals are now available for the 2018 season by visiting tbirdtickets.com or the America First Events Center’s ticket office.Ticket renewals are due June 1, at which point they will become open to the general public. Written bylast_img read more

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France overpowers Croatia 4-2 to win 2nd World Cup

first_imgJuly 15, 2018 /Sports News – National France overpowers Croatia 4-2 to win 2nd World Cup Written by FacebookTwitterLinkedInEmailCatherine Ivill/Getty Images(MOSCOW) — France overwhelmed Croatia 4-2 in Moscow to win the world’s biggest international soccer tournament for the second time.France had been among the favorites to win the tournament from the outset and proved too much for Croatia, who dominated possession but were undone by an early own goal and a penalty given away before halftime.Croatia pulled two back, including one from a goalkeeping error, but it wasn’t enough with a French win cemented in the 65th minute by 19-year-old Kylian Mbappé.France’s win brings to a close one of the most unpredictable tournaments in recent years in which many of the sport’s giants fall by the wayside and underdogs exceed expectations.Croatia, while never a complete outsider, was nonetheless one of those, with a team of world-class but older players digging deep to get their country to its first World Cup final. Along the way, they dispatched two favorites going into the competition, beating the European champions, Portugal, and running roughshod over Argentina in a spectacular 3-1 win. They also ended the host Russia’s unlikely World Cup run, defeating them in the quarterfinals.France, by contrast, started as a favorite and have driven toward the final with a single-minded determination that’s produced results, if not always excitement. A young team flush with talent, they have turned their brilliance on and off when required — winning a stunning 4-3 victory against Argentina, coming from behind with some of the most spectacular goals of the tournament. But in the final group-state match they settled for an infuriating 0-0 draw with Denmark where both sides essentially agreed not to play, needing just 1 point each to qualify for the following round. In the semifinal, France elected to smother a creative Belgium, suffocating its attack and relying on a single goal.French President Emmanuel Macron attended the game in Moscow’s Luzhniki stadium, as did Russian President Vladimir Putin. Macron and Putin will met for talks first in the Kremlin.The final brings to an end a World Cup for Russia that has also, for a month a least, transformed the cities in which it was held, with a party atmosphere reigning and fans from a bewildering combination of countries dancing in the streets and partying every night for weeks on end. In Moscow, residents have been stunned at what has been permitted during the competition, and the light touch of police, who stood by and allowed the party to go on, including drinking that’s normally forbidden in public areas, and wild scenes right up to the Kremlin.Fears that the competition would be marred by violence from soccer hooligans — over-emphasized by some media before the tournament — never materialized thanks to an aggressive crackdown by Russia’s security services. Fans arriving in Moscow also enjoyed the city, which has received a colossal makeover in recent years, and some were surprised at the thriving restaurants and bars that have appeared to replace the post-Soviet gloom many expected.The tournament has without doubt been a boon for the Kremlin in altering the country’s perception on the world stage, temporarily competing with headlines about its bombing campaign in Syria, war in Ukraine, nerve-agent poisonings in Britain, political repression at home and election meddling in the United States and elsewhere.But few expect the spell will last far beyond Sunday’s final when the last fans begin to leave Moscow and Putin on Monday heads for Finland for his first summit with Trump.Russian Police have already said that drinking laws will be reasserted, waving flags in the Red Square will likely be ill-advised and climbing lampposts to shout probably will end in arrest. Even during the tournament, two prominent human rights activists were detained for holding signs calling for the release of Oyub Titiev, who leads the rights group Memorial in Chechnya and who is currently on trial.That case and others will remain once the tournament ends, including that of Oleg Sentsov, a Ukrainian film director who has been on hunger strike in a Russian jail for 63 days while demanding the release of three dozen other Ukrainian political prisoners.The World Cup though will perhaps leave a mark on Russia, beyond the stadiums built or refurbished in 11 cities across the European half of the country. It will also be remembered for Russia’s own team’s shocking success, reaching the semifinals for the first time since 1970 by beating Spain, having been dismissed even by their own fans as likely not to even reach the knockout stages.“Moscow will never be like this again,” one woman shouted in joyful amazement to a reporter after that match.It will perhaps also be remembered as a moment when Russia and the rest of the world could have fun together. Copyright © 2018, ABC Radio. All rights reserved.center_img Beau Lundlast_img read more

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USU Football To Have Two Conference Road Games Aired on AT&T Sports Net

first_imgAugust 15, 2018 /Sports News – Local USU Football To Have Two Conference Road Games Aired on AT&T Sports Net Brad James FacebookTwitterLinkedInEmailLOGAN, Utah-Wednesday, Utah State University football announced two of its road games in Mountain West play will be live broadcasts on AT&T SportsNet.These are the Aggies’ October 20 road game at Wyoming and the November 13 game at Colorado State.The game at Laramie, Wyo. is a 12:30 p.m. broadcast with the game at Fort Collins, Colo. kicking off at high noon. Written by Tags: AT&T SportsNet/Colorado State/USU Football/Wyominglast_img

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