Coral Reef Island Initiation and Development Under Higher Than Present Sea Levels

Coral reef islands are considered to be among the most vulnerable environments to future sea-level rise. However, emerging data suggest that different island types, in contrasting locations, have formed under different conditions in relation to past sea level. Uniform assumptions about reef island futures under sea-level rise may thus be inappropriate. Using chronostratigraphic analysis from atoll rim islands (sand- and gravel-based) in the southern Maldives, we show that whilst island building initiated at different times around the atoll (~2,800 cal. yr. B.P. and ~4,200 cal. yr. B.P. at windward and leeward rim sites respectively), higher than present sea levels and associated high-energy wave events were actually critical to island initiation. Findings thus suggest that projected sea-level rise and increases in the magnitude of distal high-energy wave events could reactivate this process regime which, if there is an appropriate sediment supply, may facilitate further vertical reef island-building

Exploring the limits of saving a subspecies: The ethics and social dynamics of restoring northern white rhinos (Ceratotherium simum cottoni)

Abstract The northern white rhino (Ceratotherium simum cottoni) is functionally extinct with only two females left alive. However, cryopreserved material from a number of individuals represents the potential to produce additional individuals using advanced reproductive and genetic rescue technologies and perhaps eventually a population to return to their native range. If this could and were done, how should it be done responsibly and thoughtfully. What issues and questions of a technical, bioethical, and societal nature will it raise that need to be anticipated and addressed? Such issues are explored in this article by an interdisciplinary team assembled to provide context to the northern white rhino project of the San Diego Zoo Global

Bounded rationality and the Brexit negotiations:Why Britain failed to understand the EU

Research on the Brexit negotiations has linked the problems faced by Britain to flawed assumptions in the UK’s perception of EU interests. These include the idea that the EU would be open to compromise on key principles, that it would offer the UK a bespoke relationship, that national capitals would respond favourably to bilateral initiatives, and that EU unity would not hold. Yet the origins of these assumptions have been subject to little systematic scrutiny. How did such wrong-headed assumptions about the EU’s interests emerge? Drawing on insights from bounded rationality we identify three aspects of the decision-making environment linked with biased thinking: (1) ill-fitting routines and lessons, (2) a lack of decision-making openness, and (3) a lack of EU expertize and contact. We demonstrate our argument using data obtained from interviews in Brussels and London in 2017–18 and accounts of those involved in the decisions

Combining measurements and modeling/simulations analysis to assess carbon nanotube memory cell characteristics

A simulation package for CNT memory cells is developed, based on computational modeling of both the mesoscopic structure of carbon nanotube films and the electrical conductivity of inter-CNT contacts. The developed package enables the modeling of various electrical measurements and identification of a range of operation conditions delivering desirable device characteristics. This approach opens the path for optimization of the CNT fabric to meet performance requirements

Measurement of quasi-elastic 12C(p,2p) scattering at high momentum transfer

We measured the high-momentum quasi-elastic 12C(p,2p) reaction (at center of mass angle near 90 degrees) for 6 and 7.5 GeV/c incident protons. The three-momentum components of both final state protons were measured and the missing energy and momentum of the target proton in the nucleus were determined. The validity of the quasi-elastic picture was verified up to Fermi momenta of about 450 MeV/c, where it might be questionable. Transverse and longitudinal Fermi momentum distributions of the target proton were measured and compared to independent particle models which do not reproduce the large momentum tails. We also observed that the transverse Fermi distribution gets wider as the longitudinal component increases in the beam direction, in contrast to a simple Fermi gas model.Comment: 4 pages including 3 figure

Randomized double-blind phase II survival study comparing immunization with the anti-idiotypic monoclonal antibody 105AD7 against placebo in advanced colorectal cancer

The cancer vaccine 105AD7 is an anti-idiotypic monoclonal antibody that mimics the tumour-associated antigen 791T/gp72 (CD55, Decay Accelerating Factor) on colorectal cancer cells. Phase I studies in patients with advanced disease confirmed that 105AD7 is non-toxic, and that T cell responses could be generated. A prospective, randomized, double-blind, placebo-controlled survival study in patients with advanced colorectal cancer was performed. 162 patients were enrolled between April 1994 and October 1996. Patients attended at trial entry, and at 6 and 12 weeks, where they received 105AD7 or placebo. Study groups were comparable in terms of patient demographics, and time from diagnosis of advanced colorectal cancer (277.1 v 278.6 days). Baseline disease was similar, with 50% of patients having malignancy in at least 2 anatomic sites. Compliance with treatment was poor, with only 50% of patients receiving 3 planned vaccinations. Median survival from randomization date was 124 and 184 days in 105AD7 and placebo arms respectively (P = 0.38), and 456 and 486 days from the date of diagnosis of advanced disease (P = 0.82). 105AD7 vaccination does not prolong survival in patients with advanced colorectal cancer. The reasons for lack of efficacy are unclear, but may reflect the high tumour burden in the patient population, and poor compliance with immunization. Further vaccine studies should concentrate on patients with minimal residual disease. © 2001 Cancer Research Campaign http://www.bjcancer.co

Solar-like oscillations and magnetic activity of the slow rotator EK Eri

We aim to understand the interplay between non-radial oscillations and stellar magnetic activity and test the feasibility of doing asteroseismology of magnetically active stars. We analyze 30 years of photometric time-series data, 3 years of HARPS radial velocity monitoring, and 3 nights of high-cadence HARPS asteroseismic data. We construct a high-S/N HARPS spectrum that we use to determine atmospheric parameters and chemical composition. Spectra observed at different rotation phases are analyzed to search for signs of temperature or abundance variations. An upper limit on the projected rotational velocity is derived from very high-resolution CES spectra. We detect oscillations in EK Eri with a frequency of the maximum power of nu_max = 320+/-32 muHz, and we derive a peak amplitude per radial mode of ~0.15 m/s, which is a factor of ~3 lower than expected. We suggest that the magnetic field may act to suppress low-degree modes. Individual frequencies can not be extracted from the available data. We derive accurate atmospheric parameters, refining our previous analysis. We confirm that the main light variation is due to cool spots, but that other contributions may need to be taken into account. We suggest that the rotation period is twice the photometric period, i.e., P_rot = 2 P_phot = 617.6 d. We conclude from our derived parameters that v sin i < 0.40 km/s. We also link the time series of direct magnetic field measurements available in the literature to our newly derived photometric ephemeris.Comment: 11 pages, 10 figures. Accepted by A&

Mitigating switching variability in carbon nanotube memristors

Root-cause of instability in carbon nanotubes memristors is analyzed employing ultra-short pulse technique in combination with atomic-level material modeling. Separating various factors affecting switching operations allowed to identify structural features and operational conditions leading to improved cell characteristics

Towards Efficient Integrated Perovskite/Organic Bulk Heterojunction Solar Cells: Interfacial Energetic Requirement to Reduce Charge Carrier Recombination Losses

Integrated perovskite/organic bulk heterojunction (BHJ) solar cells have the potential to enhance the efficiency of perovskite solar cells by a simple one‐step deposition of an organic BHJ blend photoactive layer on top of the perovskite absorber. It is found that inverted structure integrated solar cells show significantly increased short‐circuit current (Jsc) gained from the complementary absorption of the organic BHJ layer compared to the reference perovskite‐only devices. However, this increase in Jsc is not directly reflected as an increase in power conversion efficiency of the devices due to a loss of fill factor. Herein, the origin of this efficiency loss is investigated. It is found that a significant energetic barrier (≈250 meV) exists at the perovskite/organic BHJ interface. This interfacial barrier prevents efficient transport of photogenerated charge carriers (holes) from the BHJ layer to the perovskite layer, leading to charge accumulation at the perovskite/BHJ interface. Such accumulation is found to cause undesirable recombination of charge carriers, lowering surface photovoltage of the photoactive layers and device efficiency via fill factor loss. The results highlight a critical role of the interfacial energetics in such integrated cells and provide useful guidelines for photoactive materials (both perovskite and organic semiconductors) required for high‐performance devices