Episodes of Early Pleistocene West Antarctic Ice Sheet Retreat Recorded by Iceberg Alley Sediments

Ice loss in the Southern Hemisphere has been greatest over the past 30 years in West Antarctica. The high sensitivity of this region to climate change has motivated geologists to examine marine sedimentary records for evidence of past episodes of West Antarctic Ice Sheet (WAIS) instability. Sediments accumulating in the Scotia Sea are useful to examine for this purpose because they receive iceberg-rafted debris (IBRD) sourced from the Pacific- and Atlantic-facing sectors of West Antarctica. Here we report on the sedimentology and provenance of the oldest of three cm-scale coarse-grained layers recovered from this sea at International Ocean Discovery Program Site U1538. These layers are preserved in opal-rich sediments deposited ∼1.2 Ma during a relatively warm regional climate. Our microCT-based analysis of the layer's in-situ fabric confirms its ice-rafted origin. We further infer that it is the product of an intense but short-lived episode of IBRD deposition. Based on the petrography of its sand fraction and the Phanerozoic 40Ar/39Ar ages of hornblende and mica it contains, we conclude that the IBRD it contains was likely sourced from the Weddell Sea and/or Amundsen Sea embayment(s) of West Antarctica. We attribute the high concentrations of IBRD in these layers to “dirty” icebergs calved from the WAIS following its retreat inland from its modern grounding line. These layers also sit at the top of a ∼366-m thick Pliocene and early Pleistocene sequence that is much more dropstone-rich than its overlying sediments. We speculate this fact may reflect that WAIS mass-balance was highly dynamic during the ∼41-kyr (inter)glacial world.Postprin

Antiphased dust deposition and productivity in the Antarctic Zone over 1.5 million years

The Southern Ocean paleoceanography provides key insights into how iron fertilization and oceanic productivity developed through Pleistocene ice-ages and their role in influencing the carbon cycle. We report a high-resolution record of dust deposition and ocean productivity for the Antarctic Zone, close to the main dust source, Patagonia. Our deep-ocean records cover the last 1.5 Ma, thus doubling that from Antarctic ice-cores. We find a 5 to 15-fold increase in dust deposition during glacials and a 2 to 5-fold increase in biogenic silica deposition, reflecting higher ocean productivity during interglacials. This antiphasing persisted throughout the last 25 glacial cycles. Dust deposition became more pronounced across the Mid-Pleistocene Transition (MPT) in the Southern Hemisphere, with an abrupt shift suggesting more severe glaciations since ~0.9 Ma. Productivity was intermediate pre-MPT, lowest during the MPT and highest since 0.4 Ma. Generally, glacials experienced extended sea-ice cover, reduced bottom-water export and Weddell Gyre dynamics, which helped lower atmospheric CO2 levels.Postprin

Ancient marine sediment DNA reveals diatom transition in Antarctica

Antarctica is one of the most vulnerable regions to climate change on Earth and studying the past and present responses of this polar marine ecosystem to environmental change is a matter of urgency. Sedimentary ancient DNA (sedaDNA) analysis can provide such insights into past ecosystem-wide changes. Here we present authenticated (through extensive contamination control and sedaDNA damage analysis) metagenomic marine eukaryote sedaDNA from the Scotia Sea region acquired during IODP Expedition 382. We also provide a marine eukaryote sedaDNA record of ~1 Mio. years and diatom and chlorophyte sedaDNA dating back to ~540 ka (using taxonomic marker genes SSU, LSU, psbO). We find evidence of warm phases being associated with high relative diatom abundance, and a marked transition from diatoms comprising <10% of all eukaryotes prior to ~14.5 ka, to ~50% after this time, i.e., following Meltwater Pulse 1A, alongside a composition change from sea-ice to openocean species. Our study demonstrates that sedaDNA tools can be expanded to hundreds of thousands of years, opening the pathway to the study of ecosystem-wide marine shifts and paleo-productivity phases throughout multiple glacial-interglacial cycles.Antarctica is one of the most vulnerable regions to climate change on Earth and studying the past and present responses of this polar marine ecosystem to environmental change is a matter of urgency. Sedimentary ancient DNA (sedaDNA) analysis can provide such insights into past ecosystem-wide changes. Here we present authenticated (through extensive contamination control and sedaDNA damage analysis) metagenomic marine eukaryote sedaDNA from the Scotia Sea region acquired during IODP Expedition 382. We also provide a marine eukaryote sedaDNA record of ~1 Mio. years and diatom and chlorophyte sedaDNA dating back to ~540 ka (using taxonomic marker genes SSU, LSU, psbO). We find evidence of warm phases being associated with high relative diatom abundance, and a marked transition from diatoms comprising <10% of all eukaryotes prior to ~14.5 ka, to ~50% after this time, i.e., following Meltwater Pulse 1A, alongside a composition change from sea-ice to open-ocean species. Our study demonstrates that sedaDNA tools can be expanded to hundreds of thousands of years, opening the pathway to the study of ecosystem-wide marine shifts and paleo-productivity phases throughout multiple glacial-interglacial cycles.Postprin

The quest for successful Atlantic salmon restoration: perspectives, priorities, and maxims

Atlantic salmon is often a focal species of restoration efforts throughout the north Atlantic and it is therefore an excellent case study for how best to design programmes to address and mitigate threats and correct population declines. This perspective is written to promote the work that has been accomplished towards restoration of Atlantic salmon populations and synthesize how we believe the lessons can be used effectively to support efforts by management agencies to restore populations. We reviewed where restoration is needed for Atlantic salmon, agreed on definitions for three levels of successful restoration, and then applied these criteria to 49 published papers focused on Atlantic salmon restoration. We identified 16 successful examples of restoration among 49 papers reviewed and discussed what interventions led to success versus failure. We then addressed key questions about when hatchery stocking should be used as part of a restoration measure and whether local restoration efforts are enough when these wide-ranging species encounter broad-scale changes in the north Atlantic, specifically related to issues of climate change and to marine survival. We advise to avoid restoration as much as possible by protecting and managing existing populations and when restoration is necessary, problems should be identified and addressed in partnership with river users. With appropriate resources and research to resolve ongoing mysteries, restoration of lost Atlantic salmon populations is absolutely feasible

The Labour of Love: Seasonal Migration from Jharkhand to the Brick Kilns of Other States in India

Seasonal casual labour migration in India has conventionally been understood as the result of extreme poverty whereby villagers are forced to become migrants for the dry six months to subsist or merely survive. This article draws on fieldwork in a village in Jharkhand and a brick kiln in West Bengal to argue that migrants do not understand their movement in economic terms alone. Many see the brick kilns as a temporary space of freedom to escape problems back home, explore a new country, gain independence from parents or live out prohibited amorous relationships. It is suggested that Jharkhandi activists and policy-makers’ construction of such migration as a ‘problem’ is as much about their vision of how the new tribal state ought to be as about exploitation. Migration to the kilns is seen by them as a threat to the purity and regulation of the social and sexual tribal citizen. This moralising perspective creates a climate that paradoxically encourages many young people to flee to the brick kilns where they can live ‘freely’. In this way, the new puritanism at home helps to reproduce the conditions for capitalist exploitation and the extraction of surplus value

A measurement of the tau mass and the first CPT test with tau leptons

We measure the mass of the tau lepton to be 1775.1+-1.6(stat)+-1.0(syst.) MeV using tau pairs from Z0 decays. To test CPT invariance we compare the masses of the positively and negatively charged tau leptons. The relative mass difference is found to be smaller than 3.0 10^-3 at the 90% confidence level.Comment: 10 pages, 4 figures, Submitted to Phys. Letts.

Measurement of the B0 Lifetime and Oscillation Frequency using B0->D*+l-v decays

The lifetime and oscillation frequency of the B0 meson has been measured using B0->D*+l-v decays recorded on the Z0 peak with the OPAL detector at LEP. The D*+ -> D0pi+ decays were reconstructed using an inclusive technique and the production flavour of the B0 mesons was determined using a combination of tags from the rest of the event. The results t_B0 = 1.541 +- 0.028 +- 0.023 ps, Dm_d = 0.497 +- 0.024 +- 0.025 ps-1 were obtained, where in each case the first error is statistical and the second systematic.Comment: 17 pages, 4 figures, submitted to Phys. Lett.

WW Production Cross Section and W Branching Fractions in e+e- Collisions at 189 GeV

From a data sample of 183 pb^-1 recorded at a center-of-mass energy of roots = 189 GeV with the OPAL detector at LEP, 3068 W-pair candidate events are selected. Assuming Standard Model W boson decay branching fractions, the W-pair production cross section is measured to be sigmaWW = 16.30 +- 0.34(stat.) +- 0.18(syst.) pb. When combined with previous OPAL measurements, the W boson branching fraction to hadrons is determined to be 68.32 +- 0.61(stat.) +- 0.28(syst.) % assuming lepton universality. These results are consistent with Standard Model expectations.Comment: 22 pages, 5 figures, submitted to Phys. Lett.

Bringing emotion to work: Emotional intelligence, resistance, and the reinvention of character

This article centrally examines the sociological significance of emotional intelligence (EI) as a nascent managerial discourse. Through developing a three-way reading of the writers Richard Sennett, Daniel Goleman, and George Ritzer, it is contended that EI can be understood to signal ‘new rules’ for work involving demands for workers to develop moral character better attuned to the dynamics of the flexible workplace - character that is more ‘intelligent’, adaptive, and reflexive. Furthermore, it is argued that while EI appears in some important respects to open the scope for worker discretion, it might also signal diminished scope for worker resistance. However, ultimately, the case of EI is used to problematise recent discussions of worker resistance - to suggest the possibility of ‘resistant’ worker agency exercised through collusion with, as well as transgression of, corporate norms and practices

Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results