The Private Provision of International Impure Public Goods: the Case of Climate Policy

We discuss a tax-transfer scheme that aims at addressing the under-provision problem associated with the private supply of international public goods and at bringing about Pareto optimal allocations internationally. In particular, we consider the example of the global public good ‘climate stabilisation’, both in an analytical and a numerical simulation model. The proposed scheme levies Pigouvian taxes globally, while international sidepayments are employed in order to provide incentives to individual countries for not taking a free-ride from the international Pigouvian tax scheme. The side-payments, in turn, are financed via the environmental taxes. As a distinctive feature we take into account ancillary benefits that may be associated with local public characteristics of climate policy. We determine the positive impact that ancillary effects may exert on the scope for financing side-payments via environmental taxation. A particular attractive feature of ancillary benefits is that they arise shortly after the implementation of climate policies and therefore yield an almost immediate payback of investments in abatement efforts. Especially in times of high public debt levels, long periods of amortisation would tend to reduce political support for investments in climate policy.

The response function of a sphere in a viscoelastic two-fluid medium

In order to address basic questions of importance to microrheology, we study the dynamics of a rigid sphere embedded in a model viscoelastic medium consisting of an elastic network permeated by a viscous fluid. We calculate the complete response of a single bead in this medium to an external force and compare the result to the commonly-accepted, generalized Stokes-Einstein relation (GSER). We find that our response function is well approximated by the GSER only within a particular frequency range determined by the material parameters of both the bead and the network. We then discuss the relevance of this result to recent experiments. Finally we discuss the approximations made in our solution of the response function by comparing our results to the exact solution for the response function of a bead in a viscous (Newtonian) fluid.Comment: 12 pages, 2 figure

Anomalous Chromomagnetic Moments of Quarks and Large Transverse Energy Jets

We consider the jet cross sections for gluons coupling to quarks with an anomalous chromomagnetic moment. We then apply this to the deviation and bounds from QCD found in the CDF and D0 Fermilab data, respectively, to find a range of possible values for the anomalous moments. The quadratic and quartic terms in the anomalous moments can fit to the rise of a deviation with transverse energy. Since previous analyses have been done on the top quark total cross section, here we assume the same moment on all quarks except the top and find the range $|\kappa'| \equiv |\kappa/(2 m_q)| = 1.0\pm 0.3$ TeV$^{-1}$ for the CDF data. Assuming the anomalous moment is present only on a charm or bottom quark which is pair produced results in a range $|\kappa'_{b,c}| = 3.5 \pm 1.0$ TeV$^{-1}$. The magnitudes here are compared with anomalous magnetic moments that could account for $R_b$ and found to be in the same general range, as well as not inconsistent with LEP and SLD bounds on $\Delta \Gamma_{\text{had}}$.Comment: REVTeX, 11 pages, 2 postscript figure

Split Fermions in Extra Dimensions and Exponentially Small Cross-Sections at Future Colliders

We point out a dramatic new experimental signature for a class of theories with extra dimensions, where quarks and leptons are localized at slightly separated parallel ``walls'' whereas gauge and Higgs fields live in the bulk of the extra dimensions. The separation forbids direct local couplings between quarks and leptons, allowing for an elegant solution to the proton decay problem. We show that scattering cross sections for collisions of fermions which are separated in the extra dimensions vanish exponentially at energies high enough to probe the separation distance. This is because the separation puts a lower bound on the attainable impact parameter in the collision. We present cross sections for two body high energy scattering and estimate the power with which future colliders can probe this scenario, finding sensitivity to inverse fermion separations of order 10-70 TeV.Comment: 18 pages, 3 figure

Functional outcomes across development in offspring of parents with bipolar disorder

Objective: Whereas the risk and course of psychopathology in offspring of parents with bipolar disorder (BD) have been the primary focus of high-risk offspring studies to date, functional outcomes have not been given much attention. We present a systematic review of functional outcomes and quality of life (QoL) across development in offspring of parents with BD and aim to explore the role of offspring psychopathology in these outcomes. Method: We searched Embase, MEDLINE, PsycINFO, Web of Science, Cochrane Central, and Google Scholar from inception to June 24, 2022, for studies referring to functional outcomes (global, social, academic or occupational) or QoL in offspring of parents with BD. Results: From the 6470 records identified, 39 studies were retained (global = 17; social = 17; school = 16; occupational = 3; QoL = 5), including 13 studies that examined multiple domains. For all domains, high heterogeneity was found in study methods and quality. Only 56 % of studies adjusted for offspring psychopathology, impeding interpretation. Global and social functioning generally seemed to be impaired among older offspring (&gt;16 years). Academic performance appeared to be unaffected. School behavior, occupational functioning, and QoL showed mixed results. Offspring psychopathology is associated with social functioning, but the relationship of offspring psychopathology with other domains is less clear. Conclusion: Studies on functional outcome in offspring of parents with BD show predominantly mixed results. Inconsistent adjustment of psychopathology and age limits conclusive interpretation. Functional outcomes should be prioritized as research topics in high-risk studies and the potential associations between familial risk status, offspring psychopathology, and age may inform prevention strategies.</p

Gaugephobic Higgs Signals at the LHC

The Gaugephobic Higgs model provides an interpolation between three different models of electroweak symmetry breaking: Higgsless models, Randall-Sundrum models, and the Standard Model. At parameter points between the extremes, Standard Model Higgs signals are present at reduced rates, and Higgsless Kaluza-Klein excitations are present with shifted masses and couplings, as well as signals from exotic quarks necessary to protect the Zbb coupling. Using a new implementation of the model in SHERPA, we show the LHC signals which differentiate the generic Gaugephobic Higgs model from its limiting cases. These are all signals involving a Higgs coupling to a Kaluza-Klein gauge boson or quark. We identify the clean signal $p p \to W^(i) \to W H$ mediated by a Kaluza-Klein W, which can be present at large rates and is enhanced for even Kaluza-Klein numbers. Due to the very hard lepton coming from the W decay, this signature has little background, and provides a better discovery channel for the Higgs than any of the Standard Model modes, over its entire mass range. A Higgs radiated from new heavy quarks also has large rates, but is much less promising due to very high multiplicity final states.Comment: 16 pages, 8 figure

Predicting the optimal amount of time to spend learning before designating protected habitat for threatened species

1. Deciding when to protect threatened species habitat when complete knowledge about the habitat extent is uncertain is a common problem in conservation. More accurate habitat mapping improves conservation outcomes once that habitat is protected. However, delaying protection to improve accuracy can lead to species decline or, at worst, local extinction when threats to that habitat continue unabated before protection is implemented. Hence, there is a trade-off between gaining knowledge and taking conservation action. 2. We quantified this trade-off and determined the optimal time to spend learning about a species' habitat before protecting that habitat. We used a range of hypothetical learning curves to model improvements in the accuracy of predicted habitat over time, and receiver operating characteristic (ROC) curves to model the corresponding increase in the proportion of habitat protected. We used rates of habitat loss to model the impact of delaying habitat protection and derived analytical solutions to the problem for different types of learning curves. 3. We illustrate our approach using two threatened species, the koala Phascolarctos cinereus in Australia and northern abalone Haliotis kamtschatkana in Canada. Our approach confirms that when impacts of threatening processes are incurred rapidly, the need for timely protection is high, and the optimal time to spend learning is short for all learning curves. When the rate of habitat loss is low, we benefit from better habitat identification, and the optimal time to protect is sensitive to assumptions about how we learn and the proportion of non-habitat we are willing to protect unnecessarily. 4. Navigating the trade-off between information gain and timely action is a common problem in conservation. By optimizing the trade-off between the benefits of improving mapping accuracy and the costs of delaying protection, we provide guidelines on the effective allocation of resources between habitat identification and habitat protection. Importantly, by explicitly modelling this trade-off with a range of learning curves and estimates of the rates of habitat loss or other threatening processes, we can predict the optimal time to spend learning even when relatively little is known about a species and its habitat.Abbey E. Camaclang, Iadine Chadès, Tara G. Martin, Hugh P. Possingha