391 research outputs found
Priority for the Worse Off and the Social Cost of Carbon
The social cost of carbon (SCC) is a monetary measure of the harms from carbon emission. Specifically, it is the reduction in current consumption that produces a loss in social welfare equivalent to that caused by the emission of a ton of CO2. The standard approach is to calculate the SCC using a discounted-utilitarian social welfare function (SWF)—one that simply adds up the well-being numbers (utilities) of individuals, as discounted by a weighting factor that decreases with time. The discounted-utilitarian SWF has been criticized both for ignoring the distribution of well-being, and for including an arbitrary preference for earlier generations. Here, we use a prioritarian SWF, with no time-discount factor, to calculate the SCC in the integrated assessment model RICE. Prioritarianism is a well-developed concept in ethics and theoretical welfare economics, but has been, thus far, little used in climate scholarship. The core idea is to give greater weight to well-being changes affecting worse off individuals. We find substantial differences between the discounted-utilitarian and non-discounted prioritarian SCC
Set optimization - a rather short introduction
Recent developments in set optimization are surveyed and extended including
various set relations as well as fundamental constructions of a convex analysis
for set- and vector-valued functions, and duality for set optimization
problems. Extensive sections with bibliographical comments summarize the state
of the art. Applications to vector optimization and financial risk measures are
discussed along with algorithmic approaches to set optimization problems
Detecting controlling nodes of boolean regulatory networks
Boolean models of regulatory networks are assumed to be tolerant to perturbations. That qualitatively implies that each function can only depend on a few nodes. Biologically motivated constraints further show that functions found in Boolean regulatory networks belong to certain classes of functions, for example, the unate functions. It turns out that these classes have specific properties in the Fourier domain. That motivates us to study the problem of detecting controlling nodes in classes of Boolean networks using spectral techniques. We consider networks with unbalanced functions and functions of an average sensitivity less than 23k, where k is the number of controlling variables for a function. Further, we consider the class of 1-low networks which include unate networks, linear threshold networks, and networks with nested canalyzing functions. We show that the application of spectral learning algorithms leads to both better time and sample complexity for the detection of controlling nodes compared with algorithms based on exhaustive search. For a particular algorithm, we state analytical upper bounds on the number of samples needed to find the controlling nodes of the Boolean functions. Further, improved algorithms for detecting controlling nodes in large-scale unate networks are given and numerically studied
Determination of the size distribution of non-spherical nanoparticles by electric birefringence-based methods
The in situ determination of the size distribution of dispersed non-spherical nanoparticles is an essential
characterization tool for the investigation and use of colloidal suspensions. In this work, we test a size
characterization method based on the measurement of the transient behaviour of the birefringence
induced in the dispersions by pulsed electric fields. The specific shape of such relaxations depends on the
distribution of the rotational diffusion coefficient of the suspended particles. We analyse the measured
transient birefringence with three approaches: the stretched-exponential, Watson-Jennings, and multiexponential
methods. These are applied to six different types of rod-like and planar particles: PTFE
rods, goethite needles, single- and double-walled carbon nanotubes, sodium montmorillonite particles
and gibbsite platelets. The results are compared to electron microscopy and dynamic light scattering
measurements. The methods here considered provide good or excellent results in all cases, proving that
the analysis of the transient birefringence is a powerful tool to obtain complete size distributions of
non-spherical particles in suspension.Financial support of this investigation by Junta de Andalucía, Spain (grant No. PE2012-FQM0694) and University
of Granada (Program “Proyectos de investigación precompetitivos”) is gratefully acknowledged
Decentralization's impact on the health workforce: Perspectives of managers, workers and national leaders
Designers and implementers of decentralization and other reform measures have focused much attention on financial and structural reform measures, but ignored their human resource implications. Concern is mounting about the impact that the reallocation of roles and responsibilities has had on the health workforce and its management, but the experiences and lessons of different countries have not been widely shared. This paper examines evidence from published literature on decentralization's impact on the demand side of the human resource equation, as well as the factors that have contributed to the impact. The elements that make such an impact analysis exceptionally complex are identified. They include the mode of decentralization that a country is implementing, the level of responsibility for the salary budget and pay determination, and the civil service status of transferred health workers. The main body of the paper is devoted to examining decentralization's impact on human resource issues from three different perspectives: that of local health managers, health workers themselves, and national health leaders. These three groups have different concerns in the human resource realm, and consequently, have been differently affected by decentralization processes. The paper concludes with recommendations regarding three key concerns that national authorities and international agencies should give prompt attention to. They are (1) defining the essential human resource policy, planning and management skills for national human resource managers who work in decentralized countries, and developing training programs to equip them with such skills; (2) supporting research that focuses on improving the knowledge base of how different modes of decentralization impact on staffing equity; and (3) identifying factors that most critically influence health worker motivation and performance under decentralization, and documenting the most cost-effective best practices to improve them. Notable experiences from South Africa, Ghana, Indonesia and Mexico are shared in an annex
Allotransplanted Neurons Used to Repair Peripheral Nerve Injury Do Not Elicit Overt Immunogenicity
A major problem hindering the development of autograft alternatives for repairing peripheral nerve injuries is immunogenicity. We have previously shown successful regeneration in transected rat sciatic nerves using conduits filled with allogeneic dorsal root ganglion (DRG) cells without any immunosuppression. In this study, we re-examined the immunogenicity of our DRG neuron implanted conduits as a potential strategy to overcome transplant rejection. A biodegradable NeuraGen® tube was infused with pure DRG neurons or Schwann cells cultured from a rat strain differing from the host rats and used to repair 8 mm gaps in the sciatic nerve. We observed enhanced regeneration with allogeneic cells compared to empty conduits 16 weeks post-surgery, but morphological analyses suggest recovery comparable to the healthy nerves was not achieved. The degree of regeneration was indistinguishable between DRG and Schwann cell allografts although immunogenicity assessments revealed substantially increased presence of Interferon gamma (IFN-γ) in Schwann cell allografts compared to the DRG allografts by two weeks post-surgery. Macrophage infiltration of the regenerated nerve graft in the DRG group 16 weeks post-surgery was below the level of the empty conduit (0.56 fold change from NG; p<0.05) while the Schwann cell group revealed significantly higher counts (1.29 fold change from NG; p<0.001). Major histocompatibility complex I (MHC I) molecules were present in significantly increased levels in the DRG and Schwann cell allograft groups compared to the hollow NG conduit and the Sham healthy nerve. Our results confirmed previous studies that have reported Schwann cells as being immunogenic, likely due to MHC I expression. Nerve gap injuries are difficult to repair; our data suggest that DRG neurons are superior medium to implant inside conduit tubes due to reduced immunogenicity and represent a potential treatment strategy that could be preferable to the current gold standard of autologous nerve transplant
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