The Impact of Air Temperature on Mortality, Morbidity, and Healthcare Cost in the Medicare Population

Abstract: This paper merges weekly average temperature data from the National Oceanic Atmospheric Administration’s National Climatic Data Center (NDCC) with Medicare claims data in order to analyze the impact of high and low temperatures on mortality, onset of new chronic conditions, and hospital spending. We find a U-shaped pattern to mortality, with high and low temperature weeks exhibiting higher mortality than a 70 degree reference week. The marginal deaths in extreme weeks are healthier than the typical person who dies in the reference week, but less healthy than the population as a whole. We find some evidence of short-term mortality displacement at moderately high temperatures, but not at extremely high temperatures and not for low temperatures, where the impact tends to grow over time. High temperatures are associated with increased onset of new chronic conditions, while low temperatures are associated with lower onset, although this result may be driven by differences in the propensity to access the health care system. In the short run, high temperatures are associated with increased Medicare hospital spending and lower temperatures are associated with decreased hospital spending, although over a one month period both high- and low-temperature weeks are associated with increased hospital spending. Using conventional figures for the value of a life year lost, we find the additional healthcare spending induced by a hot week to be about 3-6% of the mortality cost

Coherent Electron-Phonon Coupling in Tailored Quantum Systems

The coupling between a two-level system and its environment leads to decoherence. Within the context of coherent manipulation of electronic or quasiparticle states in nanostructures, it is crucial to understand the sources of decoherence. Here, we study the effect of electron-phonon coupling in a graphene and an InAs nanowire double quantum dot. Our measurements reveal oscillations of the double quantum dot current periodic in energy detuning between the two levels. These periodic peaks are more pronounced in the nanowire than in graphene, and disappear when the temperature is increased. We attribute the oscillations to an interference effect between two alternative inelastic decay paths involving acoustic phonons present in these materials. This interpretation predicts the oscillations to wash out when temperature is increased, as observed experimentally.Comment: 11 pages, 4 figure

Graphene Rings in Magnetic Fields: Aharonov-Bohm Effect and Valley Splitting

We study the conductance of mesoscopic graphene rings in the presence of a perpendicular magnetic field by means of numerical calculations based on a tight-binding model. First, we consider the magnetoconductance of such rings and observe the Aharonov-Bohm effect. We investigate different regimes of the magnetic flux up to the quantum Hall regime, where the Aharonov-Bohm oscillations are suppressed. Results for both clean (ballistic) and disordered (diffusive) rings are presented. Second, we study rings with smooth mass boundary that are weakly coupled to leads. We show that the valley degeneracy of the eigenstates in closed graphene rings can be lifted by a small magnetic flux, and that this lifting can be observed in the transport properties of the system.Comment: 12 pages, 9 figure

Gate-defined graphene double quantum dot and excited state spectroscopy

A double quantum dot is formed in a graphene nanoribbon device using three top gates. These gates independently change the number of electrons on each dot and tune the inter-dot coupling. Transport through excited states is observed in the weakly coupled double dot regime. We extract from the measurements all relevant capacitances of the double dot system, as well as the quantized level spacing

A semi-parametric approach to estimate risk functions associated with multi-dimensional exposure profiles: application to smoking and lung cancer

A common characteristic of environmental epidemiology is the multi-dimensional aspect of exposure patterns, frequently reduced to a cumulative exposure for simplicity of analysis. By adopting a flexible Bayesian clustering approach, we explore the risk function linking exposure history to disease. This approach is applied here to study the relationship between different smoking characteristics and lung cancer in the framework of a population based case control study

Tunable Graphene Single Electron Transistor

We report electronic transport experiments on a graphene single electron transistor. The device consists of a graphene island connected to source and drain electrodes via two narrow graphene constrictions. It is electrostatically tunable by three lateral graphene gates and an additional back gate. The tunneling coupling is a strongly nonmonotonic function of gate voltage indicating the presence of localized states in the barriers. We investigate energy scales for the tunneling gap, the resonances in the constrictions and for the Coulomb blockade resonances. From Coulomb diamond measurements in different device configurations (i.e. barrier configurations) we extract a charging energy of 3.4 meV and estimate a characteristic energy scale for the constriction resonances of 10 meV.Comment: 6 pages and 5 figure

Quantum dots and spin qubits in graphene

This is a review on graphene quantum dots and their use as a host for spin qubits. We discuss the advantages but also the challenges to use graphene quantum dots for spin qubits as compared to the more standard materials like GaAs. We start with an overview of this young and fascinating field and will then discuss gate-tunable quantum dots in detail. We calculate the bound states for three different quantum dot architectures where a bulk gap allows for confinement via electrostatic fields: (i) graphene nanoribbons with armchair boundary, (ii) a disc in single-layer graphene, and (iii) a disc in bilayer graphene. In order for graphene quantum dots to be useful in the context of spin qubits, one needs to find reliable ways to break the valley-degeneracy. This is achieved here, either by a specific termination of graphene in (i) or in (ii) and (iii) by a magnetic field, without the need of a specific boundary. We further discuss how to manipulate spin in these quantum dots and explain the mechanism of spin decoherence and relaxation caused by spin-orbit interaction in combination with electron-phonon coupling, and by hyperfine interaction with the nuclear spin system.Comment: 23 pages, 10 figures, topical review prepared for Nanotechnolog

Compilation of results of the ICPPR non-Apis working group with a special focus on the bumblebee acute oral and contact toxicity ring test 2014 ICPPR Non-Apis Working Group

Although honeybee risk assessment for chemicals has been rigorously revised recently, methods and techniques available for non-apis pollinators are scarce. An ICPPR working group “non-apis” was established in 2013 to address these knowledge gaps. Acute contact tests were designed and performed with solitary bees Osmia sp. but still require further optimization. Ring tests on acute oral and contact toxicity for the bumblebee Bombus sp. were developed and performed in 2014. Thirteen European laboratories participated in the trials and in most cases control mortality was < 10% after 96h, indicating that the developed methodologies were feasible in a variety of laboratories. The oral exposure and the group contact exposure tests were each found to generate more variable LD50 estimates, whereas the endpoints obtained in the single contact tests were more consistent among laboratories. The difference in the two different contact test designs indicates the presence of a ‘housing’ effect, which makes the group housing less favorable. In addition, the use of Tween80 as a wetting agent was found to be unsuccessful