1,395 research outputs found
Flexible insurance for long-term care: A study of stated preferences
Aging societies need efficient and flexible systems to finance care for the frail elderly. We study pre-retirees' demand for flexible insurance that can finance informal long-term care by paying income in poor health states instead of reimbursing formal care costs. We collect and analyze stated preferences for this long-term care income product, and preferences for informal care. When asked to allocate wealth to a life annuity, a liquid investment and flexible long-term care insurance, around 75% of our sample of 1008 pre-retirees choose some long-term care cover. Study participants treat long-term care income insurance as a complement to informal care from their families. Females who expect to rely exclusively on extensive care from family members prefer more cover than similar males. We also find that if long-term care income insurance were available, some healthier seniors would purchase additional longevity insurance, using liquid funds otherwise set aside to self-insure long-term care risk
Long-term carbon and nitrogen dynamics at SPRUCE revealed through stable isotopes in peat profiles
Peatlands encode information about past vegetation dynamics, climate, and microbial processes. Here, we used δ15N and δ13C patterns from 16 peat profiles to deduce how the biogeochemistry of the Marcell S1 forested bog in northern Minnesota responded to environmental and vegetation change over the past  ∼ 10000 years. In multiple regression analyses, δ15N and δ13C correlated strongly with depth, plot location, C∕N, %N, and each other. Correlations with %N, %C, C∕N, and the other isotope accounted for 80% of variance for δ15N and 38% of variance for δ13C, reflecting N and C losses. In contrast, correlations with depth and topography (hummock or hollow) reflected peatland successional history and climate. Higher δ15N in plots closer to uplands may reflect upland-derived DON inputs and accompanying shifts in N dynamics in the lagg drainage area surrounding the bog. The Suess effect (declining δ13CO2 since the Industrial Revolution) lowered δ13C in recent surficial samples. High δ15N from −35 to −55cm probably indicated the depth of ectomycorrhizal activity after tree colonization of the peatland over the last 400 years, as confirmed by the occasional presence of wood down to −35cm depth. High δ13C at  ∼ 4000 years BP (−65 to −105cm) could reflect a transition at that time to slower rates of peat accumulation, when 13C discrimination during peat decomposition may increase in importance. Low δ13C and high δ15N at −213 and −225cm ( ∼ 8500 years BP) corresponded to a warm period during a sedge-dominated rich fen stage. The above processes appear to be the primary drivers of the observed isotopic patterns, whereas there was no clear evidence for methane dynamics influencing δ13C patterns
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Using scenarios to explore UK upland futures
Uplands around the world are facing significant social, economic and environmental changes, and decision-makers need to better understand what the future may hold if they are to adapt and maintain upland goods and services. This paper draws together all major research comprising eight studies that have used scenarios to describe possible futures for UK uplands. The paper evaluates which scenarios are perceived by stakeholders to be most likely and desirable, and assesses the benefits and drawbacks of the scenario methods used in UK uplands to date. Stakeholders agreed that the most desirable and likely scenario would be a continuation of hill farming (albeit at reduced levels) based on cross-compliance with environmental measures. The least desirable scenario is a withdrawal of government financial support for hill farming. Although this was deemed by stakeholders to be the least likely scenario, the loss of government support warrants close attention due to its potential implications for the local economy. Stakeholders noted that the environmental implications of this scenario are much less clear-cut. As such, there is an urgent need to understand the full implications of this scenario, so that upland stakeholders can adequately prepare, and policy-makers can better evaluate the likely implications of different policy options. The paper concludes that in future, upland scenario research needs to: (1) better integrate in-depth and representative participation from stakeholders during both scenario development and evaluation; and (2) make more effective use of visualisation techniques and simulation models
Dynamic optimal taxation with human capital.
This paper revisits the dynamic optimal taxation results of Jones, Manuelli, and Rossi (1993, 1997). They use a growth model with human capital and find that optimal taxes on both capital income and labor income converge to zero in steady state. For one of the models under consideration, I show that the representative household's problem does not have an interior solution. This raises concerns since these corners are inconsistent with aggregate data. Interiority is restored if preferences are modified so that human capital augments the value of leisure time. With this change, the optimal tax problem is analyzed and, reassuringly, the Jones, Manuelli, and Rossi results are confirmed: neither capital income nor labor income should be taxed in steady state
Assimilating Remote Sensing Observations of Leaf Area Index and Soil Moisture for Wheat Yield Estimates: An Observing System Simulation Experiment
Observing system simulation experiments were used to investigate ensemble Bayesian state updating data assimilation of observations of leaf area index (LAI) and soil moisture (theta) for the purpose of improving single-season wheat yield estimates with the Decision Support System for Agrotechnology Transfer (DSSAT) CropSim-Ceres model. Assimilation was conducted in an energy-limited environment and a water-limited environment. Modeling uncertainty was prescribed to weather inputs, soil parameters and initial conditions, and cultivar parameters and through perturbations to model state transition equations. The ensemble Kalman filter and the sequential importance resampling filter were tested for the ability to attenuate effects of these types of uncertainty on yield estimates. LAI and theta observations were synthesized according to characteristics of existing remote sensing data, and effects of observation error were tested. Results indicate that the potential for assimilation to improve end-of-season yield estimates is low. Limitations are due to a lack of root zone soil moisture information, error in LAI observations, and a lack of correlation between leaf and grain growth
Reference systems for the determination of 10B through autoradiography images: Application to a melanoma experimental model
The amount of 10B in tissue samples may be determined by measuring the track density in the autoradiography image produced on a nuclear track detector. Different systems were evaluated as reference standards to be used for a quantitative evaluation of boron concentration. The obtained calibration curves were applied to evaluate the concentration of 10B in melanoma tumour of NIH nude mice after a biodistribution study. The histological features observed in the tissue sections were accurately reproduced by the autoradiography images.Fil: Portu, Agustina Mariana. Comisión Nacional de EnergÃa Atómica. Centro Atómico Constituyentes; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas; ArgentinaFil: Carpano, M.. Comisión Nacional de EnergÃa Atómica. Centro Atómico Constituyentes; ArgentinaFil: Dagrosa, MarÃa Alejandra. Consejo Nacional de Investigaciones CientÃficas y Técnicas; Argentina. Comisión Nacional de EnergÃa Atómica. Centro Atómico Constituyentes; ArgentinaFil: Nievas, S.. Comisión Nacional de EnergÃa Atómica. Centro Atómico Constituyentes; ArgentinaFil: Pozzi, E.. Comisión Nacional de EnergÃa Atómica. Centro Atómico Constituyentes; ArgentinaFil: Thorp, S.. Comisión Nacional de EnergÃa Atómica. Centro Atómico Constituyentes; ArgentinaFil: Cabrini, R.. Comisión Nacional de EnergÃa Atómica. Centro Atómico Constituyentes; Argentina. Universidad de Buenos Aires. Facultad de OdontologÃa; ArgentinaFil: Liberman, S.. Comisión Nacional de EnergÃa Atómica. Centro Atómico Constituyentes; ArgentinaFil: Saint Martin, MarÃa Laura Gisela. Comisión Nacional de EnergÃa Atómica. Centro Atómico Constituyentes; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas; Argentin
Characterizing the Cool KOIs. VI. H- and K-band Spectra of Kepler M Dwarf Planet-Candidate Hosts
We present H- and K-band spectra for late-type Kepler Objects of Interest
(the "Cool KOIs"): low-mass stars with transiting-planet candidates discovered
by NASA's Kepler Mission that are listed on the NASA Exoplanet Archive. We
acquired spectra of 103 Cool KOIs and used the indices and calibrations of
Rojas-Ayala et al. to determine their spectral types, stellar effective
temperatures and metallicities, significantly augmenting previously published
values. We interpolate our measured effective temperatures and metallicities
onto evolutionary isochrones to determine stellar masses, radii, luminosities
and distances, assuming the stars have settled onto the main-sequence. As a
choice of isochrones, we use a new suite of Dartmouth predictions that reliably
include mid-to-late M dwarf stars. We identify five M4V stars: KOI-961
(confirmed as Kepler 42), KOI-2704, KOI-2842, KOI-4290, and the secondary
component to visual binary KOI-1725, which we call KOI-1725 B. We also identify
a peculiar star, KOI-3497, which has a Na and Ca lines consistent with a dwarf
star but CO lines consistent with a giant. Visible-wavelength adaptive optics
imaging reveals two objects within a 1 arc second diameter; however, the
objects' colors are peculiar. The spectra and properties presented in this
paper serve as a resource for prioritizing follow-up observations and planet
validation efforts for the Cool KOIs, and are all available for download online
using the "data behind the figure" feature.Comment: Accepted for publication in the Astrophysical Journal Supplement
Series (ApJS). Data and table are available in the sourc
Riverine macrosystems ecology: sensitivity, resistance, and resilience of whole river basins with human alterations
Riverine macrosystems are described here as watershed-scale networks of connected and interacting riverine and upland habitat patches. Such systems are driven by variable responses of nutrients and organisms to a suite of global and regional factors (eg climate, human social systems) interacting with finer-scale variations in geology, topography, and human modifications. We hypothesize that spatial heterogeneity, connectivity, and asynchrony among these patches regulate ecological dynamics of whole networks, altering system sensitivity, resistance, and resilience. Long-distance connections between patches may be particularly important in riverine macrosystems, shaping fundamental system properties. Furthermore, the type, extent, intensity, and spatial configuration of human activities (eg land-use change, dam construction) influence watershed-wide ecological properties through effects on habitat heterogeneity and connectivity at multiple scales. Thus, riverine macrosystems are coupled social–ecological systems with feedbacks that influence system responses to environmental change and the sustainable delivery of ecosystem services
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