Northern Sourced Water dominated the Atlantic Ocean during the Last Glacial Maximum

Increased carbon sequestration in the ocean subsurface is commonly assumed to have been one of the main causes responsible for lower glacial atmospheric CO2 concentrations. Remineralized carbon must have been stored away from the atmosphere for thousands of years, yet the water mass structure accommodating such increased carbon storage continues to be debated. Here, we present new sediment-derived bottom-water neodymium isotope records that allow fingerprinting of water masses and provide a more complete picture of the Atlantic Meridional Overturning Circulation geometry during the Last Glacial Maximum. These results suggest that the vertical and meridional structure of the Atlantic water mass distribution only experienced minor changes since the last ice age. In particular, we find no compelling evidence supporting glacial southern-sourced water substantially expanding to shallower depths and farther into the Northern Hemisphere than today, which had been previously inferred from stable carbon isotope (δ13C) reconstructions. We argue that depleted δ13C values observed in the deep Northwest Atlantic do not necessarily indicate the presence of southern-sourced water. Instead, these values may represent a northern-sourced water mass with lower than modern preformed δ13C values that were further modified downstream by increased sequestration of remineralized carbon, facilitated by a more sluggish glacial deep circulation, corroborating previous evidence

The health and social care costs of a selection of health conditions and multi-morbidities

Background Multimorbidity (MM) is the presence of 2 or more long-term health conditions in a single individual. It impacts an individual’s quality of life, mental health and wellbeing, daily function, and often results in greater healthcare utilisation the more co-existing conditions they have (1-4). MM is a big challenge facing the NHS, especially given England’s ageing population, with an estimated two-thirds of individuals aged 65 and over having 2 or more long-term conditions (5-6). Yet, little is known about the resource use of these patients despite being the group with the largest impact on the NHS and with the worst health outcomes (7). Existing evidence focuses on specific health conditions and their interactions with other conditions using different methodologies, making comparisons across different conditions difficult. This work has empirically assessed the impact of multi-morbidity on NHS and social care costs. With the aim of answering the question: is the impact of developing a condition on health and social care costs greater for someone with no prior conditions, or for someone with an existing condition. If patients have multiple conditions, there may be some economies of scale involved with treatment, for example they may be able to discuss multiple queries during a single GP appointment, or in some cases the treatment provided will address multiple conditions. However, treating patients with multi-morbidities could theoretically also be more expensive than treating 2 conditions separately, as patients may be more likely to experience complications. Methodology This work considered the individual cost of 11 health conditions with high prevalence in the English population and their most common interactions. These were: chronic obstructive pulmonary disease (COPD), diabetes (types 1 and 2), lung cancer, breast cancer, coronary heart disease (CHD), stroke, hypertension, dementia, liver disease, depression and colorectal cancer. This project had 2 components: a literature review and an empirical estimation of the costs associated with MM. The literature review was used to inform and establish the methodology used in the empirical estimation. The empirical estimation used data on primary healthcare, secondary healthcare, and prescriptions usage from 2015 to estimate annual aggregated healthcare costs per patient. We assessed the cost impact of MM in a systematic way by applying advanced econometric methods to account for the specificities of the data distribution. Our methodology allowed us to attribute healthcare costs to specific conditions. For social care costs, we calculated the estimated costs using 2 different methodologies. For the first (preferred) methodology, we used Somerset Symphony data to calculate the 2014/15 social care costs of patients in South Somerset. This is a dataset that combines primary healthcare, secondary healthcare, and social care data. We thus applied the same methodology that was used to calculate primary and secondary healthcare costs. For the second methodology, we used the estimated health-related quality of life for patients with different conditions and combinations of conditions. We then used a regression (‘line of best fit’) to estimate their probability of requiring social care. Finally, we used unit cost estimates to arrive at estimated values for the costs of social care for individuals with different diseases. What this publication adds Average ‘cost per case’ estimates for individuals with single conditions or multimorbidities, each calculated based on the average age of patients with the condition or multi-morbidity of interest. These average ‘costs per case’ figures are always higher for individuals with multimorbidities than individuals with a single condition, as individuals with multi-morbidities tend to be older and additional conditions incur additional costs. We found that the cost of treating an individual with a multimorbidity is not statistically different than the additive cost of treating 2 individuals, each with one of the conditions, controlling for age and costs unrelated to the condition. As an illustrative example, if it costs £200 to treat a patient with depression and £200 to treat a patient with CHD, we did not find any evidence that it would cost more than £400 to treat a single patient with both depression and CHD (controlling for age and unrelated disease costs). In numerous cases, when considering healthcare costs, we have found that multimorbidity is associated with a reduction of the total individual cost compared to the sum of individual costs of patients. For example, a male patient with diabetes and CHD will cost between 77% and 78% (depending on the definition of sample prevalence) of the cost of treating 2 patients, one with diabetes and one with CHD, controlling for age and unrelated costs. Applying the same methodology for social care costs as for healthcare costs, we did not find any evidence that multi-morbidity is associated with either an increase or a reduction in total individual cost compared to the sum of individual costs of patient, for social care costs. This may be due to the relatively small sample size of the South Somerset data we used to estimate social care costs. Applying the alternative methodology for social care costs, which estimated social care need based on age and quality of life, we estimated higher social care costs than we found by analysing the South Somerset data. This implies that social care need may be greater than local authority social costs in South Somerset. This may be due to the relative affluence of South Somerset, which would limit the proportion of patients eligible for local authority-funded social care

Low terrestrial carbon storage at the Last Glacial Maximum: constraints from multi-proxy data

Past changes in the inventory of carbon stored in vegetation and soils remain uncertain. Earlier studies inferred the increase in the land carbon inventory (Δland) between the Last Glacial Maximum (LGM) and the preindustrial period (PI) based on marine and atmospheric stable carbon isotope reconstructions, with recent estimates yielding 300–400&thinsp;GtC. Surprisingly, however, earlier studies considered a mass balance for the ocean–atmosphere–land biosphere system only. Notably, these studies neglect carbon exchange with marine sediments, weathering–burial flux imbalances, and the influence of the transient deglacial reorganization on the isotopic budgets. We show this simplification to significantly reduce Δland in simulations using the Bern3D Earth System Model of Intermediate Complexity v.2.0s. We constrain Δland to ∼850&thinsp;GtC (median estimate; 450 to 1250&thinsp;GtC ±1SD) by using reconstructed changes in atmospheric δ13C, marine δ13C, deep Pacific carbonate ion concentration, and atmospheric CO2 as observational targets in a Monte Carlo ensemble with half a million members. It is highly unlikely that the land carbon inventory was larger at LGM than PI. Sensitivities of the target variables to changes in individual deglacial carbon cycle processes are established from transient factorial simulations with the Bern3D model. These are used in the Monte Carlo ensemble and provide forcing–response relationships for future model–model and model–data comparisons. Our study demonstrates the importance of ocean–sediment interactions and burial as well as weathering fluxes involving marine organic matter to explain deglacial change and suggests a major upward revision of earlier isotope-based estimates of Δland.</p

Using Social Media to Promote STEM Education: Matching College Students with Role Models

STEM (Science, Technology, Engineering, and Mathematics) fields have become increasingly central to U.S. economic competitiveness and growth. The shortage in the STEM workforce has brought promoting STEM education upfront. The rapid growth of social media usage provides a unique opportunity to predict users' real-life identities and interests from online texts and photos. In this paper, we propose an innovative approach by leveraging social media to promote STEM education: matching Twitter college student users with diverse LinkedIn STEM professionals using a ranking algorithm based on the similarities of their demographics and interests. We share the belief that increasing STEM presence in the form of introducing career role models who share similar interests and demographics will inspire students to develop interests in STEM related fields and emulate their models. Our evaluation on 2,000 real college students demonstrated the accuracy of our ranking algorithm. We also design a novel implementation that recommends matched role models to the students.Comment: 16 pages, 8 figures, accepted by ECML/PKDD 2016, Industrial Trac

Probing superconductivity in MgB2 confined to magnetic field tuned cylinders by means of critical fluctuations

We report and analyze reversible magnetization measurements on a high quality MgB2 single crystal in the vicinity of the zero field transition temperature, T_c=38.83 K, at several magnetic fields up to 300 Oe, applied along the c-axis. Though MgB2 is a two gap superconductor our scaling analysis uncovers remarkable consistency with 3D-xy critical behavior, revealing that close to criticality the order parameter is a single complex scalar as in 4He. This opens up the window onto the exploration of the magnetic field induced finite size effect, whereupon the correlation length transverse to the applied magnetic field H_i applied along the i-axis cannot grow beyond the limiting magnetic length L_Hi, related to the average distance between vortex lines. We find unambiguous evidence for this finite size effect. It implies that in type II superconductors, such as MgB2, there is the 3D to 1D crossover line H_pi and xi denotes the critical amplitudes of the correlation lengths above and below T_c along the respective axis. Consequently, above H_pi(T) and T<T_c superconductivity is confined to cylinders with diameter L_Hi (1D). In contrast, above T_c the uncondensed pairs are confined to cylinders. Accordingly, there is no continuous phase transition in the (H,T)-plane along the H_c2-lines as predicted by the mean-field treatment

Kondo engineering : from single Kondo impurity to the Kondo lattice

In the first step, experiments on a single cerium or ytterbium Kondo impurity reveal the importance of the Kondo temperature by comparison to other type of couplings like the hyperfine interaction, the crystal field and the intersite coupling. The extension to a lattice is discussed. Emphasis is given on the fact that the occupation number $n_f$ of the trivalent configuration may be the implicit key variable even for the Kondo lattice. Three $(P, H, T)$ phase diagrams are discussed: CeRu$_2$Si$_2$, CeRhIn$_5$ and SmS

Two Modes of Change in Southern Ocean Productivity Over the Past Million Years

Export of organic carbon from surface waters of the Antarctic Zone of the Southern Ocean decreased during the last ice age, coinciding with declining atmospheric carbon dioxide (CO2) concentrations, signaling reduced exchange of CO2 between the ocean interior and the atmosphere. In contrast, in the Subantarctic Zone, export production increased into ice ages coinciding with rising dust fluxes, thus suggesting iron fertilization of subantarctic phytoplankton. Here, a new high-resolution productivity record from the Antarctic Zone is compiled with parallel subantarctic data over the past million years. Together, they fit the view that the combination of these two modes of Southern Ocean change determines the temporal structure of the glacial-interglacial atmospheric CO2 record, including during the interval of “lukewarm” interglacials between 450 and 800 thousand years ago

Superconducting pairing and density-wave instabilities in quasi-one-dimensional conductors

Using a renormalization group approach, we determine the phase diagram of an extended quasi-one-dimensional electron gas model that includes interchain hopping, nesting deviations and both intrachain and interchain repulsive interactions. d-wave superconductivity, which dominates over the spin-density-wave (SDW) phase at large nesting deviations, becomes unstable to the benefit of a triplet $f$-wave phase for a weak repulsive interchain backscattering term $g_1^\perp>0$, despite the persistence of dominant SDW correlations in the normal state. Antiferromagnetism becomes unstable against the formation of a charge-density-wave state when $g_1^\perp$ exceeds some critical value. While these features persist when both Umklapp processes and interchain forward scattering ($g_2^\perp$) are taken into account, the effect of $g_2^\perp$ alone is found to frustrate nearest-neighbor interchain $d$- and $f$-wave pairing and instead favor next-nearest-neighbor interchain singlet or triplet pairing. We argue that the close proximity of SDW and charge-density-wave phases, singlet d-wave and triplet $f$-wave superconducting phases in the theoretical phase diagram provides a possible explanation for recent puzzling experimental findings in the Bechgaard salts, including the coexistence of SDW and charge-density-wave phases and the possibility of a triplet pairing in the superconducting phase.Comment: 19 pages, 13 figure

Effects of Multi-Surface Modification on Curie temperature of ferroelectric films

Within the framework of mean field theory, we study the effects of multi-surface modification on Curie temperature of ferroelectric films using the transverse Ising model. The general nonlinear equations for Curie temperature of multi-surface ferroelectric films with arbitrary exchange constants and transverse fields are derived by the transfer matrix method. As an example, we consider a film consisting of top surface layers, bulk layers and bottom surface layers. Two types of surface modifications, modifications of a surface exchange constant and a surface transverse field are taken into account. The dependence of Curie temperature on the surface layer numbers, bulk layer numbers, surface exchange constants, surface transverse fields and bulk transverse fields is discussed.Comment: 11 pages, 5 figure