Efficacy of δ18O data from Pliocene planktonic foraminifer calcite for spatial sea surface temperature reconstruction : comparison with a fully coupled ocean–atmosphere GCM and fossil assemblage data for the mid-Pliocene

first_imgSea surface temperature (SST) estimates using the δ18O composition of fossil planktonic foraminifer calcite, within the time slice 3.12 to 3.05 Ma (Pliocene, Kaena Subchron – C2An1r) are assessed for nine Atlantic Ocean sites. These are compared with SST estimates from fossil assemblages for the ‘Time Slab’ 3.29–2.97 Ma and with estimates from a fully coupled ocean–atmosphere General Circulation Model (GCM) for the same time interval. Most SST estimates derived from the δ18O data indicate a cooler ocean surface than at present, through the latitudinal range 69.25° N to 46.88° S. At some sites the temperature difference is greater than 5 °C (cooler than at present). This contrasts with SST estimates from fossil assemblages that give warmer than present temperatures at mid- to high latitudes, and similar temperatures in the tropics, and with the GCM, which predicts SSTs warmer than at present across all latitudes for this time interval. Difficulties interpreting the ecology of fossil foraminifer assemblages and inaccurate estimates of mid-Pliocene seawater δ18O composition (δ18Osw) at some sites may partly produce the temperature discrepancy between isotope-based and fossil-based SST estimates, but do not adequately explain the cool signal of the former. We interpret the cool SST estimates from the δ18O data to be the product of: (a) calcite formed at a level deep within or below the ocean mixed-layer during the life-cycle of the foraminifera; (b) secondary calcite with higher δ18O formed in the planktonic foraminifer tests in sea bottom pore waters. Although these effects differ between sites, secular and temporal oceanographic trends are preserved in the primary calcite formed in the mixed-layer near the ocean surface, witnessed by the latitudinal variation in estimated SSTs. Reconstructing accurate mid-Pliocene SSTs with much of the existing published oxygen isotope data probably requires a detailed re-assessment of taphonomy, particularly at tropical sites. This study also indicates that methods for estimating Atlantic Pliocene δ18Osw need to be refined.last_img read more

Comment: An End to Oxford Application Fees?

first_imgIf it walks like a duck, and it quacks like a duck, is it a duck? Yes. So if there is something that looks like a barrier to applying to Oxford, and seems to act like a barrier to applying to Oxford, is it a barrier? Not always. The £10 application fee for undergraduate admissions quacks because it is a barrier. But we should be wary of throwing out babies out with the bath water. Or, to hideously combine these already out of control metaphors, rubber ducks with the bath water. There are some extra processes built in to applying to Oxford, like aptitude tests and interviews, that look like a barrier to applying, seem to act like a barrier to applying, but aren’t a barrier to applying. So why don’t they quack?The short answer is that some perceived barriers benefit applicants: they allow Oxford to gain a much greater understanding of a student’s potential, so the University can confidently choose the very best from the brightest. Working out who is really, really good, rather than just really good, when everyone who applies has perfect grades and a treasure chest of extra curricular achievements, is a challenge to say the least. Few universities benefit from this challenge. Oxford needs different admission processes to meet this challenge.By barriers, in the context of admissions, I mean things that block the progress of students of greatest potential, whatever their background. For Oxford to admit the best from the brightest, it must invest in extra stages to get rounded pictures of applicants. After all, academic potential cannot be accurately represented by a series of past achievements printed on a piece of paper. Therefore the University invests more time and energy than other higher education bodies rigorously interviewing applicants. The interviews allow tutors to stretch potential students’ thinking, to analyse their motivations, and to assess whether they will respond successfully to tutorial teaching. Candidates will not receive adequate care and attention from tutors if there are ten people being interviewed per place. To ensure tutors can conduct meaningful interviews, aptitude tests are used in some subjects to help short-list candidates to approximately three per place during interviews. This also prevents students with no chance of getting an offer wasting time and money coming to Oxford. This guarantees that the University admits the very best from its talented pool of applicants.Charging £10 to apply to Oxford quacks, waddles and swims like a duck, and is one that should be shot. The fee is a barrier that discourages students from applying to Oxford, because they see the application as a costly gamble. By charging students to apply, this university encourages a false assumption that life here is more expensive than everywhere else. Considering the relatively small sums it raises, compared to the millions the University invests every year into its access work and bursaries, there is no reason why the University should undermine its good work on outreach by demanding that prospective applicants buy the opportunity to be considered by Oxford.It is inevitable that this fee will go – Oxford is the last remaining University to charge for this – but its demise is also desirable. I believe applications will increase as more talented students apply speculatively; after all, it won’t cost them anything to do so. This will help our work widening access and making sure Oxford University admits the best students, whatever their school, and whatever their background.James Lamming is the Vice President of OUSU.last_img read more

NHL Draft 2019: Biggest sleepers, risers and fallers to watch when your team picks

first_imgFor all the debating and back-and-forth bickering that takes place leading up to the NHL draft, which for some is a year-long endeavor, you would think we’d all have a pretty good idea how the actual draft turns out.Although guessing and prognosticating are core characteristics of the armchair general manager, you can also lump the people who do the actual drafting into this group. That’s right, NHL GM’s and the scouts they employ sit stoically at the head of the draft-day roulette table, hoping their bets on prospects change their fortunes for the better. Sure, they do their homework and treat the draft as their respective franchise’s hinge point for wheeling in an upwards trajectory. Of course, the odds are in favor of those holding the highest slots on the draft board, but even then it’s still a gamble that can have a profound impact on not only their job security but also the future success of the organizations that employ them.NHL DRAFT 2019: SN’s Mock Draft | Big boardWhich is why it is imperative for teams to make the most of every draft pick regardless of how few or late the selections are.  Although it helps to get a first or second overall pick, most contenders build a strong supporting cast on the strength of late-round draft picks. Measuring their success can vary, but point totals and games played are two acceptable barometers to justify or validate an individual draft pick.By using scoring, individual awards and team accomplishments as an approach to gauge the success of a specific draft class, what you’ll find is that the significant amount of top players in the NHL were originally selected early in the first round of the draft. There are, however, the outliers who weren’t taken within the upper tier of their respective draft-years and went on to all-star careers in the NHL.Naturally, if you asked around NHL front offices,  you’d probably be told that scouting is, in fact, an art, and player development from the post-draft period is far from a science. Go ahead and pick a random draft year, and see how none of its highest scorers were drafted in sequential order beginning with the first overall pick. For every Mario Lemieux (1984), Sidney Crosby (2005) or Connor McDavid (2015) – each of whom was the No. 1 pick in their draft year – you’ll find a Nikita Kucherov, Sebastian Aho or Jamie Benn who were drafted outside of the first round.In the last seven years, three of the NHL’s regular-season scoring champions were not first-round picks. Including Kucherov, who was the 58th overall selection in 2011 and went on to win this year’s Hart Trophy as league MVP.This phenomenon is by no means limited to forwards. If you include undrafted Mark Giordano, who won the Norris Trophy for the best defenseman, 12 of the last 18 winners were either drafted outside the first round or weren’t drafted at all and it isn’t a fluke list either. Hockey Hall of Famer Nicklas Lidstrom, a third-rounder in 1989, accounts for seven of those trophies, while Duncan Keith (2nd Round in 2002), Zdeno Chara (3rd round in 1996) and P.K. Subban (2nd round in 2007) round out the list.NHL Draft 2019: Former Rangers GM Neil Smith on the process, mistakes and pressure on Ray SheroIn goal, the run of three straight Vezina Trophy winners who were not picked in the first round ended last night when 2012 first-rounder Andrei Vasilevskiy took home the award over Ben Bishop (3rd round in 2005) and Robin Lehner (2nd round in 2009). But the league’s most prestigious trophy – The Stanley Cup – has been reserved for starting goalies who weren’t considered first-round talents on draft day. Since Marc-Andre Fleury (1st overall in 2003) took home the Cup in 2009 with Pittsburgh, every starter on the next 10 Cup winners was drafted in the second round or later, including St. Louis Blues netminder Jordan Binnington (3rd round in 2012).As you can see, late-round success can be as critical to a team’s success as the sure things in the draft’s top five. Here are some prospects to keep an eye on during this weekend’s activities in Vancouver.Stock rising1. Spencer Knight (G, U.S. U18, NTDP)The idea that a team doesn’t need a goalie who was a high draft pick to compete for the Stanley Cup is certainly a valid one. Nonetheless, goalies with Knight’s potential don’t come around very often. With stylistic comparisons to Carey Price and Henrik Lundqvist, you can see why several teams may consider him a top-10 pick.2. Robert Mastrosimone (LW, Chicago, USHL)Being one of the last cuts from a historic program like this year’s NTDP is just one of several reasons why this high-energy sniper needs to be taken seriously by NHL scouting departments. Mastrosimone was one of the USHL’s top goal scorers and tied for the lead in playoff scoring.3. Tobias Bjornfot (LHD, Djugardens J20, Superelit)Philip Broberg and Victor Soderstrom received most of the attention this year as the cream of Sweden’s deep crop of two-way defensemen. But Bjornfot has the potential to the best of them all. An on-ice leader and sound decision maker, he can go end-to-end on one shift and smother an opposing counterattack on the next.4. Premysil Svoboda (LW, Litvinov, Extraliga)A top scorer in the Czech junior league, Svoboda has nasty offensive skills and can play the role or finisher or playmaker. He can handle a bad pass in stride as well as anyone in his class, including Jack Hughes and Kaapo Kakko.5. Jordan Spence (RHD, Moncton, QMJHL)A graceful puck mover who was one of the top-scoring defensemen in the QMJHL, Spence looked as smooth and confident for Team Canada at the under-18 world championship as he did for Moncton. He’s a crisp passer and calculated risk taker in the offensive end.More: NHL rules changes focus on coaches’ challenges, video review, player safety Top 2019 NHL Draft sleepers1. Ludvig Hedstrom (LHD, Djugardens U20, Superelit)A physical two-way defenseman who was a mainstay for Team Sweden at all the key pre-draft tournaments, Hedstrom packs a wallop in his 5’11 frame but also skates extremely well.2. Marek Berka (LW, Litvinov U20, Extraliga Juniors)One of the more explosive skaters in the draft, Berka was part of the Litvinov steamroller that included Svoboda, Dan Bartos and elite 2020 draft prospect Jan Mysak. He can finish off the rush but also plays inside and competes hard in all three zones.3. Tukka Tieksola (RW, Karpat U20)A dynamic playmaker who makes as many high-end plays in the neutral zone as he does inside the opposing end, Tieksola can dazzle you with his vision and escapability. 4. Jamieson Rees (C, Sarnia, OHL) A high-energy center who was a top player on a thin Sarnia squad, Rees can scoot and intensify his team’s collective efforts by showing them what effort and hard work look like. He was one of Canada’s best players at the U18 worlds.5. G Dustin Wolf (G, Everett, WHL)As goalies shrink down to traditional height requirements, so will the desire to only draft goalies big enough to cover every angle without moving. Wolf is a master technician who uses quickness and incredible play anticipation to smother WHL attacks the same way his Everett predecessor Carter Hart did a few seasons ago.last_img read more