3,457 research outputs found
Retinal cone photoreceptors of the deer mouse Peromyscus maniculatus : development, topography, opsin expression and spectral tuning
A quantitative analysis of photoreceptor properties was performed in the retina of the nocturnal deer mouse, Peromyscus maniculatus, using pigmented (wildtype) and albino animals. The aim was to establish whether the deer mouse is a more suitable model species than the house mouse for photoreceptor studies, and whether oculocutaneous albinism affects its photoreceptor properties. In retinal flatmounts, cone photoreceptors were identified by opsin immunostaining, and their numbers, spectral types, and distributions across the retina were determined. Rod photoreceptors were counted using differential interference contrast microscopy. Pigmented P. maniculatus have a rod-dominated retina with rod densities of about 450.000/mm(2) and cone densities of 3000 - 6500/mm(2). Two cone opsins, shortwave sensitive (S) and middle-to-longwave sensitive (M), are present and expressed in distinct cone types. Partial sequencing of the S opsin gene strongly supports UV sensitivity of the S cone visual pigment. The S cones constitute a 5-15% minority of the cones. Different from house mouse, S and M cone distributions do not have dorsoventral gradients, and coexpression of both opsins in single cones is exceptional (<2% of the cones). In albino P. maniculatus, rod densities are reduced by approximately 40% (270.000/mm(2)). Overall, cone density and the density of cones exclusively expressing S opsin are not significantly different from pigmented P. maniculatus. However, in albino retinas S opsin is coexpressed with M opsin in 60-90% of the cones and therefore the population of cones expressing only M opsin is significantly reduced to 5-25%. In conclusion, deer mouse cone properties largely conform to the general mammalian pattern, hence the deer mouse may be better suited than the house mouse for the study of certain basic cone properties, including the effects of albinism on cone opsin expression
Adaptor of last resort? An economic perspective on the governmentâs role in adaptation to climate change
Abstract Individuals and societies have always adapted to change, whether catastrophic or slow onset. Over the last two centuries, however, governments have significantly extended their role as ultimate social manager of risk. It is as yet unclear whether, how, or to what extent governments will add adaptation to climate change to their portfolio of responsibilities. This report investigates this question on the basis of review and analysis of economic and policy thinking on the issues, and by using a new dataset on the 2011 Brisbane flood. Uncertainties about the future impacts of climate change obviate definitive conclusions about future adaptation actions and insights for specific situations cannot be generalised. Economic precepts suggest that governments should limit intervention to cases of genuine market failure, such as the provision of information on likely impacts of climate change including at the local level, or to support for people affected by uninsurable events. But any role as âinsurer of last resortâ needs to be circumscribed by rigorous social cost-benefit analysis to ensure that government intervention is beneficial, in the context of the need to adapt to climatic changes. Although the phenomenon of âgovernment failureâ is generally ignored in the adaptation literature (and often by policy makers), it too can stymie efficient adaptation. A standard justification for government intervention is market failure, including misperception of risk by individuals and businesses. We use Brisbane property prices before and after the January 2011 flood, as well as property-level flood risk information to test the hypothesis that buyers do not accurately perceive the risk of riverine flooding. The results indicate that buyers do take risk into account, and even discriminate between zones of differing flood risk. The concepts of âgovernment as insurer of last resortâ and âgovernment as insurer of first resortâ as alternative forms of intervention in markets are examined with a view to disambiguation. In contrast to much current thinking in academic and government circles, we conclude that the government should not act as an âadaptor of first or last resortâ. Rather, government can best contribute to efficient adaptation by reducing the economic costs and institutional barriers to adaptation faced by individuals and organisations.Comprehensive micro-economic reform, and the promotion of institutional flexibility are potential âno regretsâ strategies because they will also promote economic growth and welfare.Please cite as: Dobes, L, Jotzo, F, DoupĂ©, P 2013 Adaptor of last resort? An economic perspective on the Governmentâs role in adaptation to climate change, National Climate Change Adaptation Research Facility, Gold Coast, pp. 81.Individuals and societies have always adapted to change, whether catastrophic or slow onset. Over the last two centuries, however, governments have significantly extended their role as ultimate social manager of risk. It is as yet unclear whether, how, or to what extent governments will add adaptation to climate change to their portfolio of responsibilities. This report investigates this question on the basis of review and analysis of economic and policy thinking on the issues, and by using a new dataset on the 2011 Brisbane flood. Uncertainties about the future impacts of climate change obviate definitive conclusions about future adaptation actions and insights for specific situations cannot be generalised. Economic precepts suggest that governments should limit intervention to cases of genuine market failure, such as the provision of information on likely impacts of climate change including at the local level, or to support for people affected by uninsurable events. But any role as âinsurer of last resortâ needs to be circumscribed by rigorous social cost-benefit analysis to ensure that government intervention is beneficial, in the context of the need to adapt to climatic changes. Although the phenomenon of âgovernment failureâ is generally ignored in the adaptation literature (and often by policy makers), it too can stymie efficient adaptation. A standard justification for government intervention is market failure, including misperception of risk by individuals and businesses. We use Brisbane property prices before and after the January 2011 flood, as well as property-level flood risk information to test the hypothesis that buyers do not accurately perceive the risk of riverine flooding. The results indicate that buyers do take risk into account, and even discriminate between zones of differing flood risk. The concepts of âgovernment as insurer of last resortâ and âgovernment as insurer of first resortâ as alternative forms of intervention in markets are examined with a view to disambiguation. In contrast to much current thinking in academic and government circles, we conclude that the government should not act as an âadaptor of first or last resortâ. Rather, government can best contribute to efficient adaptation by reducing the economic costs and institutional barriers to adaptation faced by individuals and organisations.Comprehensive micro-economic reform, and the promotion of institutional flexibility are potential âno regretsâ strategies because they will also promote economic growth and welfare.Please cite as: Dobes, L, Jotzo, F, DoupĂ©, P 2013 Adaptor of last resort? An economic perspective on the Governmentâs role in adaptation to climate change, National Climate Change Adaptation Research Facility, Gold Coast, pp. 81. 
Coherent network analysis technique for discriminating gravitational-wave bursts from instrumental noise
Existing coherent network analysis techniques for detecting
gravitational-wave bursts simultaneously test data from multiple observatories
for consistency with the expected properties of the signals. These techniques
assume the output of the detector network to be the sum of a stationary
Gaussian noise process and a gravitational-wave signal, and they may fail in
the presence of transient non-stationarities, which are common in real
detectors. In order to address this problem we introduce a consistency test
that is robust against noise non-stationarities and allows one to distinguish
between gravitational-wave bursts and noise transients. This technique does not
require any a priori knowledge of the putative burst waveform.Comment: 18 pages, 11 figures; corrected corrupted figur
Generating synthetic load profiles of residential heat pumps: a k-means clustering approach
The creation of synthetic heat pump load profiles is essential for energy system modeling and simulations. This paper proposes a methodology to create synthetic heat pump load profiles based on the k-means algorithm and a data set from water-to-water heat pumps from Hamelin, Germany. The quality of the generated load profiles is shown according to load factors, load distribution curves and the Pearson correlation coefficient, and is also applied on two exemplary geographies in Germany. We publish our work open-source and provide a web-based heat pump load profile generator
Statistical thresholds for Tensor PCA
We study the statistical limits of testing and estimation for a rank one
deformation of a Gaussian random tensor. We compute the sharp thresholds for
hypothesis testing and estimation by maximum likelihood and show that they are
the same. Furthermore, we find that the maximum likelihood estimator achieves
the maximal correlation with the planted vector among measurable estimators
above the estimation threshold. In this setting, the maximum likelihood
estimator exhibits a discontinuous BBP-type transition: below the critical
threshold the estimator is orthogonal to the planted vector, but above the
critical threshold, it achieves positive correlation which is uniformly bounded
away from zero
Land Collateral and Labor Market Dynamics in France
The value of land in the balance sheet of French firms correlates positively with their hiring and investment flows. To explore the relationship between these variables, we develop a macroeconomic model with firms that are subject to both credit and labor market frictions. The value of collateral is driven by the forward-looking dynamics of the land price, which reacts endogenously to fundamental and non-fundamental (sunspot) shocks. We calibrate the model to French data and find that land price shocks give rise to significant amplification and hump-shaped responses of investment, vacancies and unemployment that are in line with the data. We show that both the endogenous movements in the firmâs discount factor and the sluggish response of the land price are key elements that drive the results
Structure and bargaining power in multilateral negotiations : Application to water management policies in France
Environmental policies are characterized by a growing emphasis on participation, devolution and negotiated decision making. Increasingly, centralized top down decision making systems are being replaced by new forms of local governance. In their strongest versions, these involve delegation of formal authority to local stakeholders who are expected to decide collectively upon the management rules of local common-pool resources. Devolution is particularly important in relation to the allocation and management of scarce water resources. Indeed the French water law of 1992 institutionalised the notion of [...].
Structure and Power in Multilateral Negotiations: An Application to French Water Policy
Stakeholder negotiation is an increasingly important policymaking tool. However, relatively little is understood about the relationship between the structure of the negotiating process and the effectiveness with which stakeholders can pursue their individual interests. We apply the Rausser- Simon multilateral bargaining model to a specific negotiation process involving water storage capacity and use in the upper Adour Basin in southwestern France. We focus on a coalition of three stakeholder groups with aligned but distinct interests. In addition to the standard indices of bargaining powerÔŽhe distribution of political weights (ÜĄccessĘ© and playersÙ utilities if an agreement is not reached, our analysis identifies other less obvious sources of power. First, a coalition member may benefit when his access is reduced if the redistribution increases the access of another coalition member who has a more favorable Üłtrategic location.Ę Second, the interests of the coalition as a whole will usually, but not always, be advanced if its members cede access to a pokesmanĘ representing their common interests. However, some members may be adversely affected. Third, restricting the extent to which coalition members can make proposals that further their own individual interests at the expense of other coalition members will usually, but not always, harm the coalition as a whole.water, bargaining, negotiations, Environmental Economics and Policy, Institutional and Behavioral Economics,
Ontology Summit 2008 Communiqué: Towards an open ontology repository
Each annual Ontology Summit initiative makes a statement appropriate to each Summits theme as part of our general advocacy designed to bring ontology science and engineering into the mainstream. The theme this year is "Towards an Open Ontology Repository". This communiqué represents the joint position of those who were engaged in the year's summit discourse on an Open Ontology Repository (OOR) and of those who endorse below. In this discussion, we have agreed that an "ontology repository is a facility where ontologies and related information artifacts can be stored, retrieved and managed."
We believe in the promise of semantic technologies based on logic, databases and the Semantic Web, a Web of exposed data and of interpretations of that data (i.e., of semantics), using common standards. Such technologies enable distinguishable, computable, reusable, and sharable meaning of Web and other artifacts, including data, documents, and services. We also believe that making that vision a reality requires additional supporting resources and these resources should be open, extensible, and provide common services over the ontologies
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