2,415 research outputs found
Putting our money where their mouth is: alignment of charitable aims with charity investments - tensions in policy and practice
Given the values-driven nature of the mission of most charities, it might be expected that investment behaviour would be similarly values-driven. This paper documents the ethical investment policies and practices of the largest UK charities and explores how these are aligned with the charitable aims, drawing upon accountability, behavioural and managerial perspectives as theoretical lenses. The study employs two distinct research methods: responses to a postal questionnaire and follow-up semi-structured interviews with selected charities. The evidence indicates that a significant minority of large charities do not have a written ethical investment policy. Charities with larger investments, fundraising charities and religious charities were more likely to have a written ethical policy. We suggest that there is a pressing need for improved alignment between charities' aims and their investment practices and better monitoring of investment policies
Sensitivity in Multiobjective Programming by Differential Equations Methods. The Case of Homogeneous Functions
Proceedings of the Second International Conference on Multi-Objective Programming and Goal Programming, Torremolinos, Spain, May 16-18, 1996.The purpose of this paper is to characterize for convex multiobjective programming, the situations in which the sensitivity with respect to the right side vector of the constraints can be obtained as a solution of a dual program.Publicad
Categorical Dimensions of Human Odor Descriptor Space Revealed by Non-Negative Matrix Factorization
In contrast to most other sensory modalities, the basic perceptual dimensions of olfaction remain unclear. Here, we use non-negative matrix factorization (NMF) – a dimensionality reduction technique – to uncover structure in a panel of odor profiles, with each odor defined as a point in multi-dimensional descriptor space. The properties of NMF are favorable for the analysis of such lexical and perceptual data, and lead to a high-dimensional account of odor space. We further provide evidence that odor dimensions apply categorically. That is, odor space is not occupied homogenously, but rather in a discrete and intrinsically clustered manner. We discuss the potential implications of these results for the neural coding of odors, as well as for developing classifiers on larger datasets that may be useful for predicting perceptual qualities from chemical structures
Ice core measurements of 14CH4 show no evidence of methane release from methane hydrates or old permafrost carbon during a large warming event 11,600 years ago
Thawing permafrost and marine methane hydrate destabilization in the Arctic and elsewhere have been proposed as large sources of methane to the atmosphere in the future warming world. To evaluate this hypothesis it is useful to ask whether such methane releases happened during past warming events. The two major abrupt warming events of the last deglaciation, Oldest Dryas - Bølling (OD-B, ≈ 14,500 years ago) and Younger Dryas - Preboreal (YD-PB; ≈11,600 years ago), were associated with large (up to 50%) increases in atmospheric methane (CH4) concentrations. The sources of these large warming-driven CH4 increases remain incompletely understood, with possible contributions from tropical and boreal wetlands, thawing permafrost as well as marine CH4 hydrates. We present new measurements of 14C of paleoatmospheric CH4 over the YD-PB transition from ancient ice outcropping at Taylor Glacier, Antarctica. 14C can unambiguously identify CH4 emissions from "old carbon" sources, such as permafrost and CH4 hydrates. The only prior study of paleoatmospheric 14CH4 (from Greenland ice) suggested that wetlands were the main driver of the YD-PB CH4 increase, but the results were weakened by an unexpected and poorly understood 14CH4 component from in situ cosmogenic production directly in near-surface ice. In this new study, we have been able to accurately characterize and correct for the cosmogenic 14CH4 component. All samples from before, during and after the abrupt warming and associated CH4 increase yielded 14CH4 values that are consistent with 14C of atmospheric CO2 at that time, indicating a purely contemporaneous methane source. These new measurements rule out the possibility of large CH4 releases to the atmosphere from methane hydrates or old permafrost carbon in response to the large and rapid YD-PB warming. To the extent that the characteristics of the YD-PB warming are comparable to those of the current anthropogenic warming, our measurements suggest that large future atmospheric methane increases from old carbon sources in the Arctic are unlikely. Instead, our measurements indicate that global wetlands will likely respond to the warming with increased methane emissions. © European Geosciences UnionYellow Posters session, Y7
Quantitative nanoscale vortex-imaging using a cryogenic quantum magnetometer
Microscopic studies of superconductors and their vortices play a pivotal role
in our understanding of the mechanisms underlying superconductivity. Local
measurements of penetration depths or magnetic stray-fields enable access to
fundamental aspects of superconductors such as nanoscale variations of
superfluid densities or the symmetry of their order parameter. However,
experimental tools, which offer quantitative, nanoscale magnetometry and
operate over the large range of temperature and magnetic fields relevant to
address many outstanding questions in superconductivity, are still missing.
Here, we demonstrate quantitative, nanoscale magnetic imaging of Pearl vortices
in the cuprate superconductor YBCO, using a scanning quantum sensor in form of
a single Nitrogen-Vacancy (NV) electronic spin in diamond. The sensor-to-sample
distance of ~10nm we achieve allows us to observe striking deviations from the
prevalent monopole approximation in our vortex stray-field images, while we
find excellent quantitative agreement with Pearl's analytic model. Our
experiments yield a non-invasive and unambiguous determination of the system's
local London penetration depth, and are readily extended to higher temperatures
and magnetic fields. These results demonstrate the potential of quantitative
quantum sensors in benchmarking microscopic models of complex electronic
systems and open the door for further exploration of strongly correlated
electron physics using scanning NV magnetometry.Comment: Main text (5 pages, 4 figures) plus supplementary material (5 pages,
6 figures). Comments welcome. Further information under
http://www.quantum-sensing.c
An apparently normal gamma-ray burst with an unusually low luminosity
Much of progress in gamma-ray bursts has come from the studies of distant
events (redshift z~1). The brightest GRBs are the most collimated events and
seen across the Universe due to their brilliance. It has long been suspected
that nearest (and most common) events have been missed because they are not so
collimated or under-energetic or both. Here we report soft gamma-ray
observations of GRB 031203, the nearest event to date (z=0.106). This event
with a duration of 40 s and peak energy of >190 keV appears to be a typical
long duration GRB. However, the isotropic gamma-ray energy <~10^50 erg, about
three orders of magnitude smaller than the cosmological population. This event
as well as the other nearby but somewhat controversial event GRB 980425 are
clear outliers for the much discussed isotropic-energy peak-energy relation and
luminosity spectral-lag relations. Radio calorimetry shows that both these
events are under-energetic explosions. We conclude that there does indeed exist
a large population of under-energetic events.Comment: 11 pages, 3 figure
Biological effects of exposure to magnetic resonance imaging: an overview
The literature on biological effects of magnetic and electromagnetic fields commonly utilized in magnetic resonance imaging systems is surveyed here. After an introduction on the basic principles of magnetic resonance imaging and the electric and magnetic properties of biological tissues, the basic phenomena to understand the bio-effects are described in classical terms. Values of field strengths and frequencies commonly utilized in these diagnostic systems are reported in order to allow the integration of the specific literature on the bio-effects produced by magnetic resonance systems with the vast literature concerning the bio-effects produced by electromagnetic fields. This work gives an overview of the findings about the safety concerns of exposure to static magnetic fields, radio-frequency fields, and time varying magnetic field gradients, focusing primarily on the physics of the interactions between these electromagnetic fields and biological matter. The scientific literature is summarized, integrated, and critically analyzed with the help of authoritative reviews by recognized experts, international safety guidelines are also cited
Chronic psychosocial and financial burden accelerates 5-year telomere shortening: findings from the Coronary Artery Risk Development in Young Adults Study.
Leukocyte telomere length, a marker of immune system function, is sensitive to exposures such as psychosocial stressors and health-maintaining behaviors. Past research has determined that stress experienced in adulthood is associated with shorter telomere length, but is limited to mostly cross-sectional reports. We test whether repeated reports of chronic psychosocial and financial burden is associated with telomere length change over a 5-year period (years 15 and 20) from 969 participants in the Coronary Artery Risk Development in Young Adults (CARDIA) Study, a longitudinal, population-based cohort, ages 18-30 at time of recruitment in 1985. We further examine whether multisystem resiliency, comprised of social connections, health-maintaining behaviors, and psychological resources, mitigates the effects of repeated burden on telomere attrition over 5 years. Our results indicate that adults with high chronic burden do not show decreased telomere length over the 5-year period. However, these effects do vary by level of resiliency, as regression results revealed a significant interaction between chronic burden and multisystem resiliency. For individuals with high repeated chronic burden and low multisystem resiliency (1 SD below the mean), there was a significant 5-year shortening in telomere length, whereas no significant relationships between chronic burden and attrition were evident for those at moderate and higher levels of resiliency. These effects apply similarly across the three components of resiliency. Results imply that interventions should focus on establishing strong social connections, psychological resources, and health-maintaining behaviors when attempting to ameliorate stress-related decline in telomere length among at-risk individuals
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