Border Tax Adjustments: A feasible way to address nonparticipation in Emission Trading

CO2 emission certificates internalise effects of fossil fuel consumption on global climate and sea levels. If they are only implemented in some countries, then their effectiveness is limited; Consumption, production and investment decisions do not reach the optimal allocation, production with inefficient technologies in non-participating countries can even be increased. Furthermore industry lobbying might result in limited application of CO2 emission certificates or less ambitious reduction targets. Border tax adjustment at the level of additional costs incurred for procurement of CO2 emission permits during production of processed materials using best available technology limits the distortions. We show that it can be compatible with WTO constraints. Crucial features of a practicable implementation are simplicity achieved by a focus on the CO2 emissions caused by processed materials and a separate treatment of electric energy input to take account of regionally varying fuel mixes

Dephasing and Hyperfine Interaction in Carbon Nanotubes Double Quantum Dots: Disordered Case

We study theoretically the \emph{return probability experiment}, used to measure the dephasing time $T_2^*$, in a double quantum dot (DQD) in semiconducting carbon nanotubes (CNTs) with spin-orbit coupling and disorder induced valley mixing. Dephasing is due to hyperfine interaction with the spins of the ${}^{13}$C nuclei. Due to the valley and spin degrees of freedom four bounded states exist for any given longitudinal mode in the quantum dot. At zero magnetic field the spin-orbit coupling and the valley mixing split those four states into two Kramers doublets. The valley mixing term for a given dot is determined by the intra-dot disorder and therefore the states in the Kramers doublets belonging to different dots are different. We show how nonzero single-particle interdot tunneling amplitudes between states belonging to different doublets give rise to new avoided crossings, as a function of detuning, in the relevant two particle spectrum, crossing over from the two electrons in one dot states configuration, $(0,2)$, to the one electron in each dot configuration, $(1,1)$. In contrast to the clean system, multiple Landau-Zener processes affect the separation and the joining stages of each single-shot measurement and they affect the outcome of the measurement in a way that strongly depends on the initial state. We find that a well-defined return probability experiment is realized when, at each single-shot cycle, the (0,2) ground state is prepared. In this case, valley mixing increases the saturation value of the measured return probability, whereas the probability to return to the (0,2) ground state remains unchanged. Finally, we study the effect of the valley mixing in the high magnetic field limit; for a parallel magnetic field the predictions coincide with a clean nanotube, while the disorder effect is always relevant with a magnetic field perpendicular to the nanotube axis.Comment: 22 pages, 11 figure

Cotunneling renormalization in carbon nanotube quantum dots

We determine the level-shifts induced by cotunneling in a Coulomb blockaded carbon nanotube quantum dot using leading order quasi-degenerate perturbation theory within a single nanotube quartet. It is demonstrated that otherwise degenerate and equally tunnel-coupled $K$ and $K'$ states are mixed by cotunneling and therefore split up in energy except at the particle/hole-symmetric midpoints of the Coulomb diamonds. In the presence of an external magnetic field, we show that cotunneling induces a gate-dependent $g$-factor renormalization, and we outline different scenarios which might be observed experimentally, depending on the values of both intrinsic $KK'$ splitting and spin-orbit coupling.Comment: 12 pages, 7 figure

Rectification in single molecular dimers with strong polaron effect

We study theoretically the transport properties of a molecular two level system with large electron-vibron coupling in the Coulomb blockade regime. We show that when the electron-vibron coupling induces polaron states, the current-voltage characteristic becomes strongly asymmetric because, in one current direction, one of the polaron state blocks the current through the other. This situation occurs when the coupling between the polaron states is smaller than the coupling to the leads. We discuss the relevance of our calculation for experiments on C_140 molecules.Comment: 4 pages, 4 figure

Temperature and light requirements for growth of two diatom species (Bacillariophyceae) isolated from an Arctic macroalga

In the present study, two abundant epiphyticdiatom taxa were isolated from the assimilation hairs ofthe brown macroalga Chordaria flagelliformis collected inthe Arctic Kongsfjorden (Spitsbergen, Norway), establishedas unialgal cultures and their growth rates determinedunder controlled photon fluence rate andtemperature conditions. Using morphological (light andscanning electron microscopy) and SSU rRNA gene databoth isolates (ROS D99 and ROS D125) were identifiedas members of a FragilariaSynedropsis clade. Themolecular data of ROS D99 and ROS D125 were notidentical to any other published sequence. While ROSD99 has been identified as Fragilaria barbararum mainlydue to the SEM characteristics, ROS D125 could not bedefinitely identified although morphological data speakfor Fragilaria striatula. Both diatom species showedsimilar growth rates at all temperatures and photon fluencerates tested. They grew well between 0 and 15Cwithoptimum temperatures of 1214C, but did not survive20C. Therefore, compared to Antarctic diatoms bothtaxa from Kongsfjorden can be characterised as eurythermalorganisms. Increasing photon fluence rates between2 and 15 lmol m2 s1 were accompanied with analmost twofold increase in growth rates, but photon fluencerates >15 lmol m2 s1 did not further enhancegrowth pointing to low light requirements. From thesedata optimum, minimum and maximum photon fluencerates and temperatures for growth can be assessed indicatingthat both diatoms are well acclimated to the fluctuatingenvironmental conditions in the Arctic habitat

Differential Relationship between Physical Activity and Intake of Added Sugar and Nutrient-Dense Foods: A Cross-Sectional Analysis

A curvilinear relationship exists between physical activity (PA) and dietary energy intake (EI), which is reduced in moderately active when compared to inactive and highly active individuals, but the impact of PA on eating patterns remains poorly understood. Our goal was to establish the relationship between PA and intake of foods with varying energy and nutrient density. Data from the 2009–2010 United States National Health and Nutrition Examination Survey were used to include a Dietary Screener Questionnaire for estimated intakes of added sugar, fruits and vegetables, whole grains, fiber, and dairy. Participants (n = 4766; 49.7% women) were divided into sex-specific quintiles based on their habitual PA. After adjustment for age, body mass index, household income, and education, intakes were compared between PA quartiles, using the lowest activity quintile (Q1) as reference. Women in the second to fourth quintile (Q2-Q4) consumed less added sugar from sugary foods (+2 tsp/day) and from sweetened beverages (+2 tsp/day; all p \u3c 0.05 vs. Q1). In men, added sugar intake was elevated in the highest activity quintile (Q5: +3 ± 1 tsp/day, p = 0.007 vs. Q1). Fruit and vegetable intake increased (women: Q1-Q4 +0.3 ± 0.1 cup eq/day; p \u3c 0.001; men: Q1-Q3 +0.3 ± 0.1 cup eq/day, p = 0.002) and stagnated in higher quintiles. Dairy intake increased with PA only in men (Q5: +0.3 ± 0.1 cup eq/day, p \u3c 0.001 vs. Q1). Results demonstrate a differential relationship between habitual PA and dietary intakes, whereby moderate but not necessarily highest PA levels are associated with reduced added sugar and increased nutrient-dense food consumption. Future research should examine specific mechanisms of food choices at various PA levels to ensure dietary behaviors (i.e., increased sugary food intake) do not negate positive effects of PA

Spin-orbit-induced strong coupling of a single spin to a nanomechanical resonator

We theoretically investigate the deflection-induced coupling of an electron spin to vibrational motion due to spin-orbit coupling in suspended carbon nanotube quantum dots. Our estimates indicate that, with current capabilities, a quantum dot with an odd number of electrons can serve as a realization of the Jaynes-Cummings model of quantum electrodynamics in the strong-coupling regime. A quantized flexural mode of the suspended tube plays the role of the optical mode and we identify two distinct two-level subspaces, at small and large magnetic field, which can be used as qubits in this setup. The strong intrinsic spin-mechanical coupling allows for detection, as well as manipulation of the spin qubit, and may yield enhanced performance of nanotubes in sensing applications.Comment: 5 pages, 3 figures + appendix; published versio

Naturalism and the Normative Domain: Accounting for Normativity with the Help of 18th Century Empathy-Sentimentalism

Abstract: Moral sentimentalism has seen a tremendous rise in popularity in recent years within contemporary meta-ethical theory, since it promises to delineate the normative domain in a naturalistically unobjectionable manner. After showing that both Michael Slote and Jesse Prinz’s sentimentalist positions fall short of fulfilling this promise, this essay argues that contemporary sentimentalists are advised to take their clues from Adam Smith rather than David Hume. While Hume was absolutely right in emphasizing the importance of empathy in the moral context, his official description of the mechanisms of empathy as articulated in the Treatise falls fundamentally short for this purpose. Adam Smith’s conception of empathy, a conception that in fact is closer to some of Hume’ remarks in the Enquiry rather than the Treatise, as essentially involving perspective taking and his appeal to the impartial spectator perspective proves to be more fertile. Only in this manner do sentimentalists have any hope of accounting for the intersubjective normative and obligatory dimension of moral judgments.Keywords: Moral Sentimentalism; Empathy; Adam Smith; David Hume; Michael Slote; Jesse Prinz Naturalismo e dominio normativo: affermare il normativo con l’aiuto delle teorie dell’empatia e del sentimentalismo del XVIII secolo Riassunto: Negli ultimi anni il sentimentalismo morale ha conosciuto un incredibile incremento di popolarità nel dibattito meta-etico contemporaneo, poiché promette di delineare il dominio del normativo secondo una prospettiva inequivocabilmente naturalistica. Dopo aver mostrato come le posizioni sentimentaliste di Michael Slote e Jesse Prinz non sono in grado di mantenere questa promessa, in questo lavoro si afferma che i sostenitori contemporanei del sentimentalismo sono invitati a trarre ispirazione da Adam Smith piuttosto che da David Hume. Se Hume aveva assolutamente ragione nel sottolineare l’importanza dell’empatia in ambito morale, la sua descrizione ufficiale dei meccanismi dell’empatia, così come viene presentata nel Treatise, in fin dei conti non si mostra all’altezza di questo compito. La concezione dell’empatia di Adam Smith, che nei fatti è più vicina ad alcuni tratti dello Hume dell’Enquiry piuttosto che a quello del Treatise, implicando fondamentalmente l’assunzione di prospettiva e richiamando la prospettiva dello spettatore disinteressato, dimostra di essere più feconda. Solo così i teorici del sentimentalismo possono sperare di render conto del carattere necessitante e intersoggettivamente normativo dei giudizi morali.Parole chiave: Sentimentalismo morale; Empatia; Adam Smith; David Hume; Michael Slote; Jesse Prin

Gravitino Dark Matter and the Cosmic Lithium Abundances

Supersymmetric extensions of the standard model of particle physics assuming the gravitino to be the lightest supersymmetric particle (LSP), and with the next-to-LSP decaying to the gravitino during Big Bang nucleosynthesis, are analyzed. Particular emphasis is laid on their potential to solve the "Li7 problem", an apparent factor 2-4 overproduction of Li7 in standard Big Bang nucleosynthesis (BBN), their production of cosmologically important amounts of Li6, as well as the resulting gravitino dark matter densities in these models. The study includes several improvements compared to prior studies. Heavy gravitinos in the constrained minimal supersymmetric standard model (CMMSM) are reanalyzed, whereas light gravitinos in gauge-mediated supersymmetry breaking scenarios (GMSB) are studied for the first time. It is confirmed that decays of NLSP staus to heavy gravitinos, while producing all the dark matter, may at the same time resolve the Li7 problem. For NLSP decay times ~ 1000 sec, such scenarios also lead to cosmologically important Li6 (and possibly Be9) abundances. However, as such scenarios require heavy > 1 TeV staus they are likely not testable at the LHC. It is found that decays of NLSP staus to light gravitinos may lead to significant Li6 (and Be9) abundances, whereas NLSP neutralinos decaying into light gravitinos may solve the Li7 problem. Though both scenarios are testable at the LHC they may not lead to the production of the bulk of the dark matter. A section of the paper outlines particle properties required to significantly reduce the Li7 abundance, and/or enhance the Li6 (and possibly Be9) abundances, by the decay of an arbitrary relic particle.Comment: 13 pages (revtex), 9 figures, minor changes, submitted to PR