How overconfident are current projections of anthropogenic carbon dioxide emissions?

Analyzing the risks of anthropogenic climate change requires sound probabilistic projections of CO2 emissions. Previous projections have broken important new ground, but many rely on out-of-range projections, are limited to the 21st century, or provide only implicit probabilistic information. Here we take a step towards resolving these problems by assimilating globally aggregated observations of population size, economic output, and CO2 emissions over the last three centuries into a simple economic model. We use this model to derive probabilistic projections of business-as-usual CO2 emissions to the year 2150. We demonstrate how the common practice to limit the calibration timescale to decades can result in biased and overconfident projections. The range of several CO2 emission scenarios (e.g., from the Special Report on Emission Scenarios) misses potentially important tails of our projected probability density function. Studies that have interpreted the range of CO2 emission scenarios as an approximation for the full forcing uncertainty may well be biased towards overconfident climate change projections.economics of climate change, scenarios, data assimilation

How Overconfident are Current Projections of Anthropogenic Carbon Dioxide Emissions?

Analyzing the risks of anthropogenic climate change requires sound probabilistic projections of CO2 emissions. Previous projections have broken important new ground, but many rely on out-of-range projections, are limited to the 21st century, or provide only implicit probabilistic information. Here we take a step towards resolving these problems by assimilating globally aggregated observations of population size, economic output, and CO2 emissions over the last three centuries into a simple economic model. We use this model to derive probabilistic projections of business-as-usual CO2 emissions to the year 2150. We demonstrate how the common practice to limit the calibration timescale to decades can result in biased and overconfident projections. The range of several CO2 emission scenarios (e.g., from the Special Report on Emission Scenarios) misses potentially important tails of our projected probability density function. Studies that have interpreted the range of CO2 emission scenarios as an approximation for the full forcing uncertainty may well be biased towards overconfident climate change projections.Carbon Dioxide, Emissions, Scenarios, Data Assimilation, Markov Chain Monte Carlo

Competing structures in nuclei near closed shells. Final report, September 1, 1993--November 30, 1996

This report summarizes the progress made during this period. A series of experiments on levels in {sup 144}Nd have led to the identification of quadrupole-octupole coupled states in the nucleus. These experiments included the measurement of excited level lifetimes using the GRID technique, the measurement of transition conversion coefficients and the measurement of weak transition intensities. A fast electronic timing system has been set-up at Tennessee Tech. This system can be used to measure nuclear excited state lifetimes in the range from 5 ps upward. A new variation of the centroid shift method has been developed which eliminates the need to determine a prompt position. This centroid difference method employs both forward and reverse gating of gamma cascades to generate two timing spectra

Translational new approaches for investigating mood disorders in rodents and what they may reveal about the underlying neurobiology of major depressive disorder

Mood disorders represent one of society's most costly and challenging health burdens. The drug treatments used today were initially discovered serendipitously in the 1950s. Animal models were then developed based on the ability of these drugs to alter specific behaviours. These models have played a major role in the development of the second generation of antidepressants. However, their use has been heavily criticized, particularly in relation to whether they recapitulate similar underlying biology to the psychiatric disorder they are proposed to represent. This article considers our work in the field of affective bias and the development of a translational research programme to try to develop and validate better animal models. We discuss whether the new data that have arisen from these studies support an alternative perspective on the underlying neurobiological processes that lead to major depressive disorder (MDD). Specifically, this article will consider whether a neuropsychological mechanism involving affective biases plays a causal role in the development of MDD and its associated emotional and behavioural symptoms. These animal studies also raise the possibility that neuropsychological mechanisms involving affective biases are a precursor to, rather than a consequence of, the neurotrophic changes linked to MDD. This article is part of a discussion meeting issue ‘Of mice and mental health: facilitating dialogue between basic and clinical neuroscientists’.</jats:p

Type of milk feeding in infancy and health behaviours in adult life: findings from the Hertfordshire Cohort Study

A number of studies suggest that breast-feeding has beneficial effects on an individual's cardiovascular risk factors in adulthood, although the mechanisms involved are unknown. One possible explanation is that adults who were breastfed differ in their health behaviours. In a historical cohort, adult health behaviours were examined in relation to type of milk feeding in infancy. From 1931 to 1939, records were kept on all infants born in Hertfordshire, UK. Their type of milk feeding was summarised as breastfed only, breast and bottle-fed, or bottle-fed only. Information about adult health behaviours was collected from 3217 of these men and women when they were aged 59–73 years. Diet was assessed using an administered FFQ; the key dietary pattern was a ‘prudent’ pattern that described compliance with ‘healthy’ eating recommendations. Of the study population, 60 % of the men and women were breastfed, 31 % were breast and bottle-fed, and 9 % were bottle-fed. Type of milk feeding did not differ according to social class at birth, and was not related to social class attained in adult life. There were no differences in smoking status, alcohol intake or reported physical activity according to type of milk feeding, but there were differences in the participants' dietary patterns. In a multivariate model that included sex and infant weight gain, there were independent associations between type of feeding and prudent diet scores in adult life (P= 0·009), such that higher scores were associated with having been breastfed. These data support experimental findings which suggest that early dietary exposures can have lifelong influences on food choice

New experimental measurements of solvent induced swelling in nanofiltration membranes

The paper describes developmental apparatus for in-situ determinations of membrane swelling and shows representative examples of the data that can be acquired. The apparatus principally comprises a linear inductive probe and electronic column gauge with an overall resolution of 0.1 μm which was used in two configurations to assess the swelling propensity of polyacrylonitrile (PAN)/polydimethylsiloxane (PDMS) nanofiltration membranes in a range of alkane, aromatic and alcohol solvents. In the absence of an applied pressure on the membrane, experiments showed a maximum expansion for the PDMS layer of 169% using an n-heptane solvent whose solubility parameter (δ) was close to that of PDMS. With more polar solvents falling in the range δ = 23.6-29.2 MPa0.5, swelling of the PDMS was much reduced (<14%) and comparable shrinkage of the PAN support layer was also observed. If a mechanical pressure was applied to the membrane then swelling was reduced. For example with a xylene solvent, over the pressure range 0-10 bar a progressive decline in membrane swelling from 118% to 50% was observed. At 20 bar swelling was further reduced to 33%. When xylene or heptane solvent was mixed with methanol, ethanol or propanol, reduced swelling of the PDMS layer occurred as the concentration of alcohol increased. The extent of swelling was closely related to the value of the mixture solubility parameter (δmixture) where a higher value of δmixture led to less swelling. The results of the swelling experiments are compared to some of the authors previously published results for crossflow nanofiltration and shown to support the salient features

UV and X-Ray Monitoring of AG Draconis During the 1994/1995 Outbursts

The recent 1994-1995 active phase of AG Draconis has given us for the first time the opportunity to follow the full X-ray behaviour of a symbiotic star during two successive outbursts and to compare with its quiescence X-ray emission. With \ros observations we have discovered a remarkable decrease of the X-ray flux during both optical maxima, followed by a gradual recovering to the pre-outburst flux. In the UV the events were characterized by a large increase of the emission line and continuum fluxes, comparable to the behaviour of AG Dra during the 1980-81 active phase. The anticorrelation of X-ray/UV flux and optical brightness evolution is shown to very likely be due to a temperature decrease of the hot component. Such a temperature decrease could be produced by an increased mass transfer to the burning compact object, causing it to slowly expand to about twice its original size.Comment: 12 pages postscript incl. figures, Proc. of Workshop on Supersoft X-Ray Sources, to appear in Lecture Notes in Physics vol. 472 (1996

Flexible modeling of dependence in volatility processes

This paper proposes a novel stochastic volatility model that draws from the exist- ing literature on autoregressive stochastic volatility models, aggregation of autoregres- sive processes, and Bayesian nonparametric modelling to create a stochastic volatility model that can capture long range dependence. The volatility process is assumed to be the aggregate of autoregressive processes where the distribution of the autoregressive coefficients is modelled using a flexible Bayesian approach. The model provides insight into the dynamic properties of the volatility. An efficient algorithm is defined which uses recently proposed adaptive Monte Carlo methods. The proposed model is applied to the daily returns of stocks

Association of FCGR3A and FCGR3B haplotypes with rheumatoid arthritis and primary Sjögren's syndrome [POSTER PRESENTATION]

Background Rheumatoid arthritis (RA) is an autoimmune disease that is thought to arise from a complex interaction between multiple genetic factors and environmental triggers. We have previously demonstrated an association between a Fc gamma receptor (FcγR) haplotype and RA in a cross-sectional cohort of RA patients. We have sought to confirm this association in an inception cohort of RA patients and matched controls. We also extended our study to investigate a second autoanti-body associated rheumatic disease, primary Sjögren's syndrome (PSS). Methods The FCGR3A-158F/V and FCGR3B-NA1/NA2 functional polymorphisms were examined for association in an inception cohort of RA patients (n = 448), and a well-characterised PSS cohort (n = 83) from the United Kingdom. Pairwise disequilibrium coefficients (D') were calculated in 267 Blood Service healthy controls. The EHPlus program was used to estimate haplotype frequencies for patients and controls and to determine whether significant linkage disequilibrium was present. A likelihood ratio test is performed to test for differences between the haplotype frequencies in cases and controls. A permutation procedure implemented in this program enabled 1000 permutations to be performed on all haplotype associations to assess significance. Results There was significant linkage disequilibrium between FCGR3A and FCGR3B (D' = -0.445, P = 0.001). There was no significant difference in the FCGR3A or FCGR3B allele or genotype frequencies in the RA or PSS patients compared with controls. However, there was a significant difference in the FCGR3A-FCGR3B haplotype distributions with increased homozygosity for the FCGR3A-FCGR3B 158V-NA2 haplotype in both our inception RA cohort (odds ratio = 2.15, 95% confidence interval = 1.1–4.2 P = 0.027) and PSS (odds ratio = 2.83, 95% confidence interval = 1.0–8.2, P = 0.047) compared with controls. The reference group for these analyses comprised individuals who did not possess a copy of the FCGR3A-FCGR3B 158V-NA2 haplotype. Conclusions We have confirmed our original findings of association between the FCGR3A-FCGR3B 158V-NA2 haplotype and RA in a new inception cohort of RA patients. This suggests that there may be an RA-susceptibility gene at this locus. The significant increased frequency of an identical haplotype in PSS suggests the FcγR genetic locus may contribute to the pathogenesis of diverse autoantibody-mediated rheumatic diseases

Detection of NMR signals with a radio-frequency atomic magnetometer

We demonstrate detection of proton NMR signals with a radio frequency atomic magnetometer tuned to the NMR frequency of 62 kHz. High-frequency operation of the atomic magnetometer makes it relatively insensitive to ambient magnetic field noise. We obtain magnetic field sensitivity of 7 fT/Hz$^{1/2}$ using only a thin aluminum shield. We also derive an expression for the fundamental sensitivity limit of a surface inductive pick-up coil as a function of frequency and find that an atomic rf magnetometer is intrinsically more sensitive than a coil of comparable size for frequencies below about 50 MHz.Comment: 7 page