9 May

Demography and distribution of the Patagonian squid (Loligo gahi d’Orbigny) during the austral winter

first_imgA bottom-trawl survey of the Falklands Interim Conservation Zone was carried out during July and August 1988. Samples of Loligo gahi were collected from depths of 50–400 m and analysed for size composition, maturity, and stomach fullness. L. gahi increased in size and maturity with depths >100 m. Immature and fully mature squid were found at depths ≤100 m. The data support the hypothesis that this species spawns in shallow water and migrates down the continental shelf and continental slope after hatching. It then returns to shallow water to spawn. Highest concentrations of squid appeared to occur at depths and in areas where the commercial fishery operates. Samples were only taken during daylight hours, and stomach fullness was at its highest in the mid-afternoon. Several of the life history features resemble closely those of other loliginid species.last_img read more

9 May

Photosynthetic response of the Antarctic moss Polytrichum alpestre Hoppe to low temperatures and freeze-thaw stress

first_imgThe effect of low temperatures and freeze-thaw stress on photosynthetic carbon exchange in an Antarctic population of the turf-forming moss species Polytrichum alpestre Hoppe was investigated using infra-red gas analysis. Photosynthetic recovery from freezing was found to depend on the absolute depth of low temperature experienced. Repeated freeze-thaw cycles caused a greater reduction in gross photosynthesis than constant freezing over the same period of time suggesting that the freeze-thaw event itself, and not just cold temperatures, causes damage. The frequency of freeze-thaw events was significant: freeze-thaw cycles every 12 h inflicted more damage than freezethaw cycles every 24 or 48 h. Most damage occurred during the first cycle; relatively little was recorded during subsequent cycles. At +10°C, gross CO2 flux was directly proportional to moss water content between 0.3 and 3.5 g·g−1 dry mass. Moss samples with a low water content withstood freeze-thaw cycles to -5, -10 and-20°C better than samples with a high water content indicating that desiccation in the field may improve survival at low temperatures. Microclimate data for field populations of Polytrichum alpestre at Signy Island suggest that sub-zero temperatures and freeze-thaw stress may act as limiting factors on the species’ distribution and viability, particularly when the insulating effect of snow cover is small.last_img read more

9 May

Shedding new light on the life cycle of mackerel icefish in the Southern Ocean

first_imgMackerel icefish have a widespread distribution in the Atlantic and Indian Ocean sectors of the low-Antarctic region. Biological characteristics differ considerably between populations in the southern Scotia Arc and those living further to the north. Fish living in the north mature 1 year earlier than in the south. They have a much shorter life span and die after they have spawned two to three times. The number of eggs produced per gram of body mass is higher in the north. Stocks have declined in most parts of the distributional range due to the impact of fishing and due to natural causes. Increases in populations of Antarctic fur seals at South Georgia and parts of the Indian Ocean appear to have led to increased predation on stocks of icefish. Shifts in hydrological regimes in the northern part of the distributional range have either started to lead or will lead to deteriorating living conditions for mackerel icefish in the near future. Fish stock assessment needs to take these constraints into consideration when providing advice on total allowable catches for fisheries management.last_img read more

9 May

One-to-one coupling of glacial climate variability in Greenland and Antarctica

first_imgPrecise knowledge of the phase relationship between climate changes in the two hemispheres is a key for understanding the Earth’s climate dynamics. For the last glacial period, ice core studies1, 2 have revealed strong coupling of the largest millennial-scale warm events in Antarctica with the longest Dansgaard–Oeschger events in Greenland3, 4, 5 through the Atlantic meridional overturning circulation6, 7, 8. It has been unclear, however, whether the shorter Dansgaard–Oeschger events have counterparts in the shorter and less prominent Antarctic temperature variations, and whether these events are linked by the same mechanism. Here we present a glacial climate record derived from an ice core from Dronning Maud Land, Antarctica, which represents South Atlantic climate at a resolution comparable with the Greenland ice core records. After methane synchronization with an ice core from North Greenland9, the oxygen isotope record from the Dronning Maud Land ice core shows a one-to-one coupling between all Antarctic warm events and Greenland Dansgaard–Oeschger events by the bipolar seesaw6. The amplitude of the Antarctic warm events is found to be linearly dependent on the duration of the concurrent stadial in the North, suggesting that they all result from a similar reduction in the meridional overturning circulation.last_img read more

9 May

Characteristics of summer airflow over the Antarctic Peninsula in response to recent strengthening of westerly circumpolar winds

first_imgSummer near-surface temperatures over the northeast coast of the Antarctic Peninsula have increased by more than 2°C over the past 40 years, a temperature increase 3 times greater than that on the northwest coast. Recent analysis has shown a strong correlation between this striking warming trend and significant change in the summer Southern Hemisphere annular mode (SAM), which has resulted in greatly increased summer westerlies across the northern peninsula. It has been proposed that the strengthening westerlies have resulted in increased vertical deflection of relatively warm maritime air over the northern peninsula, contributing significantly to the observed warming and the recent collapse of northern sections of the Larsen Ice Shelf. In this study, laboratory and numerical modeling of airflow incident to the peninsula are employed to further understand this mechanism. It is shown that the effect of the strengthening westerlies has led to a distinct transition from a “blocked” regime to a “flow-over” regime, that is, confirmation of the proposed warming mechanism. The blocked regime is dominated by flow stagnation upstream (i.e., little vertical deflection) and consequent lateral deflection of flow along the western side of the peninsula. The flow-over regime is dominated by vertical deflection of mid/upper-level air over the peninsula, with strong downslope winds following closely to the leeward slope transporting this air (which warms adiabatically as it descends) to the near-surface of the northeast peninsula. The strong rotation typical of high latitudes considerably increases the flow over the peninsula, particularly strengthening it over the southern side (verified by aircraft measurements), suggesting that the warming trend is not solely confined to the northeast. Globally, flow regime transitions such as this may be responsible for other local climate variations.last_img read more

9 May

Transcriptome of the Atlantic halibut (Hippoglossus hippoglossus)

first_imgAlthough the Atlantic halibut (Hippoglossus hippoglossus) is an important commercial species, there is still a deficit with regard to the number of transcripts in the databases, which can be accessed and exploited for targeted candidate gene and pathway studies. In this study, the RNAs from head, skin and GI tract from different developmental stages were sequenced to generate 22,272 contigs of 500 base pairs or greater as a molecular resource for this specieslast_img

9 May

The transcriptome of metamorphosing flatfish

first_imgBackground Flatfish metamorphosis denotes the extraordinary transformation of a symmetric pelagic larva into an asymmetric benthic juvenile. Metamorphosis in vertebrates is driven by thyroid hormones (THs), but how they orchestrate the cellular, morphological and functional modifications associated with maturation to juvenile/adult states in flatfish is an enigma. Since THs act via thyroid receptors that are ligand activated transcription factors, we hypothesized that the maturation of tissues during metamorphosis should be preceded by significant modifications in the transcriptome. Targeting the unique metamorphosis of flatfish and taking advantage of the large size of Atlantic halibut (Hippoglossus hippoglossus) larvae, we determined the molecular basis of TH action using RNA sequencing. Results De novo assembly of sequences for larval head, skin and gastrointestinal tract (GI-tract) yielded 90,676, 65,530 and 38,426 contigs, respectively. More than 57 % of the assembled sequences were successfully annotated using a multi-step Blast approach. A unique set of biological processes and candidate genes were identified specifically associated with changes in morphology and function of the head, skin and GI-tract. Transcriptome dynamics during metamorphosis were mapped with SOLiD sequencing of whole larvae and revealed greater than 8,000 differentially expressed (DE) genes significantly (p < 0.05) up- or down-regulated in comparison with the juvenile stage. Candidate transcripts quantified by SOLiD and qPCR analysis were significantly (r = 0.843; p < 0.05) correlated. The majority (98 %) of DE genes during metamorphosis were not TH-responsive. TH-responsive transcripts clustered into 6 groups based on their expression pattern during metamorphosis and the majority of the 145 DE TH-responsive genes were down-regulated. Conclusions A transcriptome resource has been generated for metamorphosing Atlantic halibut and over 8,000 DE transcripts per stage were identified. Unique sets of biological processes and candidate genes were associated with changes in the head, skin and GI-tract during metamorphosis. A small proportion of DE transcripts were TH-responsive, suggesting that they trigger gene networks, signalling cascades and transcription factors, leading to the overt changes in tissue occurring during metamorphosis.last_img read more

8 May

Perfect Wilson helps BYU beat W. Michigan in Potato Bowl

first_imgDecember 21, 2018 /Sports News – Local Perfect Wilson helps BYU beat W. Michigan in Potato Bowl Tags: BYU Cougars Football/Famous Idaho Potato Bowl/Western Michigan/Zach WIlson Written by FacebookTwitterLinkedInEmailBOISE, Idaho (AP) — Zach Wilson set a BYU record and tied the NCAA bowl mark with 18-for-18 passing, throwing for 317 yards and four touchdowns in the Cougars’ 49-18 victory over Western Michigan on Friday in the Famous Idaho Potato Bowl.Selected the game MVP, Wilson tied the NCAA bowl record for completion percentage set by Riley Skinner at 11 for 11 for Wake Forest in the 2008 EagleBank Bowl.Down 10-7 at halftime, BYU (7-6) scored 28 points in the third quarter. Wilson connected with Aleva Hifo for a 70-yard scoring strike, and Riley Burt had a 37-yard touchdown run in the quarter.Western Michigan (7-6) rolled up 192 yards of offense in the first half, then managed only 41 yards on 18 plays in the decisive third quarter.THE TAKEAWAYBYU: Wilson showed that the future is bright for BYU with him under center. And with seven starters returning on a unit that finished the regular season ranked 18th in total defense, BYU will have high expectations.Wilson, who has no plans to take a break to serve an LDS mission, is the cornerstone for future success. After taking over as the starter midway through the season, he finished his freshman campaign with 1,587 passing yards and 12 touchdowns while rushing for 221 more. That bodes well for BYU to build continuity on offense, which has had a revolving door at the quarterback position over the past three seasons.Western Michigan: The Broncos have plenty of work to do to get back to the zenith of their 2016 success that ended with a Cotton Bowl berth, but the building blocks are in place. Jon Wassink, who started the season at quarterback before suffering a season-ending foot injury, will return along with leading rusher LeVante Bellamy.The defense is also in good shape, returning eight starters that include defensive leaders Drake Spears and Alex Grace, who finished first and second, respectively, on the team in tackles. Associated Presslast_img read more

8 May

Tiger Woods roars at The Masters; golfter captures 5th green jacket, 1st in 14 years

first_img FacebookTwitterLinkedInEmailAndrew Redington/Getty ImagesAUGUSTA, Ga.) —  Tiger Woods, breaking an 11-year drought since his last major championship win, scored a dramatic come-from-behind victory at The Masters tournament on Sunday.Woods won shot a 70 on the final day of the premier golfing event in Augusta, Georgia, to claim his first green jacket in 14 years and his fifth overall. He won the tournament by a single stoke, sinking a foot-long putt on the 18th hole and pumping his right fist before throwing his arms up in the air as thousands of fans on hand erupted in chants of “Tiger! Tiger! Tiger!”The 43-year-old Woods teed off the day two strokes behind Italian Francesco Molinari, but by the 12th hole he was tied for the lead and jumped to the top of the leaderboard on his own on the 15th hole. He finished the tournament 13 under par.Xander Schauffele, Duston Johnson and Brooks Koepka all tied for second, just one stroke behind Woods.The victory marked Woods 15 major championship and his first since winning the 2008 U.S. Open at the Torrey Pines golf course in San Diego.Woods last won The Masters in 2005.Copyright © 2019, ABC Radio. All rights reserved. Beau Lund Written bycenter_img April 14, 2019 /Sports News – National Tiger Woods roars at The Masters; golfter captures 5th green jacket, 1st in 14 yearslast_img read more

8 May

Washington Nationals celebrate World Series win at the White House — with a political tinge

first_imgNovember 4, 2019 /Sports News – National Washington Nationals celebrate World Series win at the White House — with a political tinge FacebookTwitterLinkedInEmailOfficial White House Photo by Andrea Hanks(WASHINGTON) — The Washington Nationals continued to celebrate their triumphant World Series win before thousands at the White House on Monday — as one player donned a “Make America Great Again” hat and another skipped the ceremony for political reasons. Almost right off the bat, Trump brought up the impeachment inquiry against him, as he discussed how popular the Nationals became throughout their season.“America fell in love with the Nats baseball,” Trump said. “They just fell in love with Nats baseball. That’s all they wanted to talk about. That and impeachment. I like Nats baseball much more.”As Trump introduced players and staff one by one, he brought catcher Kurt Suzuki to the lectern. Suzuki threw on a “Make America Great Again” hat.“I love you all,” Suzuki said. “I love you all. Thank you.”Trump hugged him. “What a job he did,” he said. “I didn’t know that was gonna happen.”Trump said the crowd on the south lawn, which the White House estimated was 5,300 people, was a record. “We’ve never had this many people on the front lawn of the White House,” he told the crowd.Running through the story of the Nationals’ season, Trump congratulated the team, who he said brought the World Series trophy “back to America’s capital.” He called the team’s owners, the Lerner family, “great people,” praised general manager Mike Rizzo, manager Dave Martinez and the other coaches and players, saying, “they’re all here.”But in fact, not all were there.Reliever Sean Doolittle told The Washington Post days ago he would not attend the ceremony.“There’s a lot of things, policies that I disagree with, but at the end of the day, it has more to do with the divisive rhetoric and the enabling of conspiracy theories and widening the divide in this country,” Doolittle said.There were at least 16 other players not in attendance, based on a list of attendees released by the White House. It was unclear why the others missed the ceremony including star third baseman Anthony Rendon.When the president praised players one by one during Monday’s ceremony, he did not mention Doolittle or Rendon.The president attended Game 5 of the World Series in Washington on Oct. 27, and was booed by fans in attendance. Some chanted, “Lock him up!”“What a month,” pitcher Max Scherzer told the crowd. “What a magical month.”After pitcher Stephen Strasburg, who this weekend became a free agent, spoke, attendees chanted, “four more years!” Trump added, “I’m going to consider that four more World Series wins.”First baseman Ryan Zimmerman handed the president a personalized Nationals jersey and thanked Trump “for keeping everyone here safe in our country and continuing to America the greatest country to live in the world.”A military band played “Baby Shark” — the team’s unofficial anthem — as the players and coaches emerged from the White House at the start of the ceremony.“That turned out to be a very, very powerful little tune,” Trump saidCopyright © 2019, ABC Audio. All rights reserved. Beau Lundcenter_img Written bylast_img read more