3,256 research outputs found
Like Father, Like Son: Justin Trudeau and Valence Voting in Canada's 2015 Federal Election
This is the author accepted manuscript. The final version is available from Cambridge University Press via the DOI in this record.Canada’s 2015 federal election was an exiting, as well as a nostalgia provoking, contest. After nine years in office, Prime Minister Stephen Harper and the governing
Conservatives were defeated by the resurgent Liberals led by Justin Trudeau. Trudeau is the son of Pierre Trudeau, perhaps Canada’s best known prime minister. Analyses of national survey data demonstrate that party leader images—a major component of the “valence politics” model of electoral choice—were important in both cases. Unlike his father, Justin Trudeau was castigated as a “lightweight” and “just not ready.” However, articulating plausible policies to jump-start Canada’s sluggish economy and espousing “sunny ways,” the younger Trudeau was warmly received by many voters. In contrast, Harper’s image of managerial competence was tarnished by bad economic news, and his attempt to refocus the campaign on emotionally charged cultural issues failed. The result was a Liberal majority government and a prime minister named Trudeau
The FRIED grid of mass-loss rates for externally irradiated protoplanetary discs
We present an open access grid of 3930 calculations of externally evaporating
protoplanetary discs. This spans a range of disc sizes (1-400AU), disc masses,
UV field strengths (10-10G) and stellar masses (0.05-1.9M). The
grid is publicly available for download, and offers a means of cheaply
including external photoevaporation in disc evolutionary calculations. It can
also be queried using an online tool for quick estimates of instantaneous mass
loss rates (e.g for convenient evaluation of real observed systems). The
`FRIED' grid itself illustrates that for discs around stars M
external photoevaporation is effective down to small radii (AU) down to UV
fields at least as weak as 10G. At the other end of the scale, in a
G environment photoevaporation is effective down to 1AU even for
stellar masses at least as high as 1.9M. We also illustrate in which
regimes CO survives in the photoevaporative outflow for significant mass loss
rates; marking a system a good candidate to detect external photoevaporation in
weak-intermediate UV environments through sub-Keplerian rotation. Finally we
make illustrative mass loss rate estimates for discs in Taurus based on the
Guilloteau et al. (2011) star-disc parameters, finding that around half are
expected to have both significant mass loss and retain CO in the
photoevaporative outflow.Comment: 16 pages, 9 figures. Accepted for publication in MNRA
The Core of the Participatory Budgeting Problem
In participatory budgeting, communities collectively decide on the allocation
of public tax dollars for local public projects. In this work, we consider the
question of fairly aggregating the preferences of community members to
determine an allocation of funds to projects. This problem is different from
standard fair resource allocation because of public goods: The allocated goods
benefit all users simultaneously. Fairness is crucial in participatory decision
making, since generating equitable outcomes is an important goal of these
processes. We argue that the classic game theoretic notion of core captures
fairness in the setting. To compute the core, we first develop a novel
characterization of a public goods market equilibrium called the Lindahl
equilibrium, which is always a core solution. We then provide the first (to our
knowledge) polynomial time algorithm for computing such an equilibrium for a
broad set of utility functions; our algorithm also generalizes (in a
non-trivial way) the well-known concept of proportional fairness. We use our
theoretical insights to perform experiments on real participatory budgeting
voting data. We empirically show that the core can be efficiently computed for
utility functions that naturally model our practical setting, and examine the
relation of the core with the familiar welfare objective. Finally, we address
concerns of incentives and mechanism design by developing a randomized
approximately dominant-strategy truthful mechanism building on the exponential
mechanism from differential privacy
Protoplanetary disc truncation mechanisms in stellar clusters: Comparing external photoevaporation and tidal encounters
Most stars form and spend their early life in regions of enhanced stellar
density. Therefore the evolution of protoplanetary discs (PPDs) hosted by such
stars are subject to the influence of other members of the cluster. Physically,
PPDs might be truncated either by photoevaporation due to ultraviolet flux from
massive stars, or tidal truncation due to close stellar encounters. Here we aim
to compare the two effects in real cluster environments. In this vein we first
review the properties of well studied stellar clusters with a focus on stellar
number density, which largely dictates the degree of tidal truncation, and far
ultraviolet (FUV) flux, which is indicative of the rate of external
photoevaporation. We then review the theoretical PPD truncation radius due to
an arbitrary encounter, additionally taking into account the role of eccentric
encounters that play a role in hot clusters with a 1D velocity dispersion
km/s. Our treatment is then applied statistically to varying
local environments to establish a canonical threshold for the local stellar
density ( pc) for which encounters can play a significant
role in shaping the distribution of PPD radii over a timescale Myr. By
combining theoretical mass loss rates due to FUV flux with viscous spreading in
a PPD we establish a similar threshold for which a massive disc is completely
destroyed by external photoevaporation. Comparing these thresholds in local
clusters we find that if either mechanism has a significant impact on the PPD
population then photoevaporation is always the dominating influence.ERC Advanced Grant grant agreement 34113
Lewis Base Passivation Mediates Charge Transfer at Perovskite Heterojunctions
Understanding interfacial charge transfer processes such as trap-mediated recombination and injection into charge transport layers (CTLs) is crucial for the improvement of perovskite solar cells. Herein, we reveal that the chemical binding of charge transport layers to CH3NH3PbI3 defect sites is an integral part of the interfacial charge injection mechanism in both n-i-p and p-i-n architectures. Specifically, we use a mixture of optical and X-ray photoelectron spectroscopy to show that binding interactions occur via Lewis base interactions between electron-donating moieties on hole transport layers and the CH3NH3PbI3 surface. We then correlate the extent of binding with an improvement in the yield and longer lifetime of injected holes with transient absorption spectroscopy. Our results show that passivation-mediated charge transfer has been occurring undetected in some of the most common perovskite configurations and elucidate a key design rule for the chemical structure of next-generation CTLs
Prevalence and correlates of physical activity across kidney disease stages: an observational multicentre study
Background:
People with chronic kidney disease (CKD) report high levels of physical inactivity, a major modifiable risk factor for morbidity and mortality. Understanding the biological, psychosocial and demographic causes of physical activity behaviour is essential for the development and improvement of potential health interventions and promotional initiatives. This study investigated the prevalence of physical inactivity and determined individual correlates of this behaviour in a large sample of patients across the spectrum of kidney disease. /
Methods:
A total of 5656 people across all stages of CKD (1–2, 3, 4–5, haemodialysis, peritoneal dialysis and renal transplant recipients) were recruited from 17 sites in England from July 2012 to October 2018. Physical activity was evaluated using the General Practice Physical Activity Questionnaire. Self-reported cardiorespiratory fitness, self-efficacy and stage of change were also assessed. Binominal generalized linear mutually adjusted models were conducted to explore the associations between physical activity and correlate variables. This cross-sectional observational multi-centre study was registered retrospectively as ISRCTN87066351 (October 2015). /
Results:
The prevalence of physical activity (6–34%) was low and worsened with disease progression. Being older, female and having a greater number of comorbidities were associated with greater odds of being physically inactive. Higher haemoglobin, cardiorespiratory fitness and self-efficacy levels were associated with increased odds of being active. Neither ethnicity nor smoking history had any effect on physical activity. /
Conclusions:
Levels of physical inactivity are high across all stages of CKD. The identification of stage-specific correlates of physical activity may help to prioritize factors in target groups of kidney patients and improve the development and improvement of public health interventions
Climate Change and invasibility of the Antarctic benthos
Benthic communities living in shallow-shelf habitats in Antarctica (<100-m depth) are archaic in their structure and function. Modern predators, including fast-moving, durophagous (skeleton-crushing) bony fish, sharks, and crabs, are rare or absent; slow-moving invertebrates are the top predators; and epifaunal suspension feeders dominate many soft substratum communities. Cooling temperatures beginning in the late Eocene excluded durophagous predators, ultimately resulting in the endemic living fauna and its unique food-web structure. Although the Southern Ocean is oceanographically isolated, the barriers to biological invasion are primarily physiological rather than geographic. Cold temperatures impose limits to performance that exclude modern predators. Global warming is now removing those physiological barriers, and crabs are reinvading Antarctica. As sea temperatures continue to rise, the invasion of durophagous predators will modernize the shelf benthos and erode the indigenous character of marine life in Antarctica
Recombinant Human Parathyroid Hormone Effect on Health-Related Quality of Life in Adults With Chronic Hypoparathyroidism
Context: Reduced health-related quality of life (HRQoL) is common in patients with hypoparathyroidism on conventional therapy with calcium and active vitamin D supplements. Objective: To examine the effects of recombinant human parathyroid hormone (rhPTH[1-84]) on HRQoL as measured by the 36-Item Short Form Health Survey (SF-36) during the multinational, randomized, placebo-controlled REPLACE study. Patients: 122 adults with chronic hypoparathyroidism. Intervention(s): Following an optimization period when calcium and/or active vitamin D supplements were adjusted to reach target serum calcium levels (8.0-9.0 mg/dL; 2.0-2.2 mmol/L), patients were randomized to receive placebo (n=39) or rhPTH(1-84) (n=83) (starting dose 50 mug/day, could be titrated up to 100 mug/day); supplement doses were adjusted to maintain target serum calcium levels. Main Outcome Measure(s): Change from baseline (post-optimization, at randomization) to Week 24 in HRQoL as assessed by the SF-36v2 health survey. Results: Overall, the between-group differences were not statistically significant. However, in the rhPTH(1-84) group, there were significant improvements in the physical component summary score (P=0.004) and in body pain (P<0.05), general health (P<0.05), and vitality (P<0.001) domains as compared with baseline values. In the placebo group, there were no significant changes for any of the domains. The magnitude of change between 0 and 24 weeks in SF-36 scores was negatively correlated with baseline scores, such that patients with lower HRQoL at baseline were more likely to experience improvement in response to treatment. Conclusions: Treatment with rhPTH(1-84) may improve HRQoL in adults with hypoparathyroidism
Induction of fibroblast senescence generates a non-fibrogenic myofibroblast phenotype that differentially impacts on cancer prognosis
Cancer-associated fibroblasts (CAF) remain a poorly characterized, heterogeneous cell population. Here we characterized two previously described tumor-promoting CAF sub-types, smooth muscle actin (SMA)-positive myofibroblasts and senescent fibroblasts, identifying a novel link between the two
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