Unusual hyperfine interaction of Dirac electrons and NMR spectroscopy in graphene

Theory of nuclear magnetic resonance (NMR) in graphene is presented. The canonical form of the electron-nucleus hyperfine interaction is strongly modified by the linear electronic dispersion. The NMR shift and spin-lattice relaxation time are calculated as function of temperature, chemical potential, and magnetic field and three distinct regimes are identified: Fermi-, Dirac-gas, and extreme quantum limit behaviors. A critical spectrometer assessment shows that NMR is within reach for fully 13C enriched graphene of reasonable size.Comment: 5 pages, 3 figure

Back In Power? Brazil\u27s Military Under Bolsonaro

It would not be an exaggeration to say that the 2018 election of Jair Bolsonaro represented the biggest shock to civil-military relations in Brazil in the last 40 years. Bolsonaro, a former Army captain who campaigned on a platform of dictatorship nostalgia amid the country’s worst-ever economic crisis, vowed to bring the generals back to the center of Brazilian politics. Indeed, the military today is exercising power not seen since Brazil concluded its decade-long “gradual transition” from dictatorship to democracy during the late 1970s and 1980s. Retired (and sometimes active-duty) senior military officers are now occupying several critical positions in the administration, including in policy areas outside the realm of defense and security – from Vice President Hamilton Mourão to ministries charged with energy, infrastructure and relations with Congress.https://digitalcommons.fiu.edu/jgi_research/1004/thumbnail.jp

Modelling the effect of the El Nino-Southern Oscillation on extreme spatial temperature events over Australia

When assessing the risk posed by high temperatures, it is necessary to consider not only the temperature at separate sites but also how many sites are expected to be hot at the same time. Hot events that cover a large area have the potential to put a great strain on health services and cause devastation to agriculture, leading to high death tolls and much economic damage. South-eastern Australia experienced a severe heatwave in early 2009; 374 people died in the state of Victoria and Melbourne recorded its highest temperature since records began in 1859 (Nairn and Fawcett, 2013). One area of particular interest in climate science is the effect of large scale climatic phenomena, such as the El Nino-Southern Oscillation (ENSO), on extreme temperatures. Here, we develop a framework based upon extreme value theory to estimate the effect of ENSO on extreme temperatures across Australia. This approach permits us to estimate the change in temperatures with ENSO at important sites, such as Melbourne, and also whether we are more likely to observe hot temperatures over a larger spatial extent during a particular phase of ENSO. To this end, we design a set of measures that can be used to effectively summarise many important spatial aspects of an extreme temperature event. These measures are estimated using our extreme value framework and we validate whether we can accurately replicate the 2009 Australian heatwave, before using the model to estimate the probability of having a more severe event than has been observed

Characterising the changing behaviour of heatwaves with climate change

Understanding the impact of future heatwaves and the development of effective adaptation strategies requires knowledge of both the changes in heatwave temperatures and their durations. We develop a framework, utilising extreme value theory, which allows for the effect of a covariate on both the marginal quantiles and the temporal dependence structure of daily maximum temperatures enabling the changes in heatwave temperatures (marginal effects) to be identified separately from duration changes (dependence effects). To characterise future heatwave changes we use global mean temperature anomalies as a covariate to provide the metric for climate change. Future daily maximum temperatures and global mean temperature changes are provided by 13 general circulation models (GCMs) from the CMIP5 archive forced with predicted future emissions of radiative forcing agents from the RCP8.5 scenario. For Orleans, central France, we find that for all GCMs temporal dependence is unaffected by greenhouse gas induced climate change indicating that durations of heatwaves that exceed time varying high thresholds (i.e., the 1 year level) will not change in the future. However, all GCMs project significant changes in the temperature margins with events similar to the 2003 European heatwave increasing by 1.3C to 2.7C and (8.0C to 18.7C) for a 1C (5C) increase in global temperature. Collectively our results indicate there could be a significant increase in heatwave risk as the world warms with heatwaves increasing in temperature significantly faster than the global mean and local average temperatures

A novel method for unambiguous ion identification in mixed ion beams extracted from an EBIT

A novel technique to identify small fluxes of mixed highly charged ion beams extracted from an Electron Beam Ion Trap (EBIT) is presented and practically demonstrated. The method exploits projectile charge state dependent potential emission of electrons as induced by ion impact on a metal surface to separate ions with identical or very similar mass-to-charge ratio.Comment: 8 pages, 5 figure

Customers’ perceptions of self-service quality

Self-service technology, SST, enables the customer to interact with a service without contact with an employee. This technology has several benefits for both customers and businesses and is a powerful tool to achieve long term success. So the quality of an SST becomes crucial for businesses in order to achieve long term success. Therefore, it becomes essential to measure the quality of an SST. The Self-service quality scale (SSTQUAL scale) purpose is to measure SST quality in several industries. The developer of this instrument, Lin and Hsieh (2011) encouraged others to do further research on the SSTQUAL scale since it is a continuous process and may change over time. Previous studies have shown that the SSTQUAL scale within the Romanian baking sector is revised. Therefore, the focus of this study will be to evaluate how service quality and the SSTQUAL scale fits in the Swedish banking sector. The study aims to identify how forest and agricultural customers in the Swedish banking sector perceive SST quality. The work is structured based on a specific case in a Swedish bank to capture how the customer perceives SST quality in these settings, and thus, the aim fulfills. The result from this study reveals that the respondents perceive five dimensions, design, functionality, security, customization, and convenience as crucial for the quality of an SST in the Swedish banking sector. The conclusions are that the customers perceive design, functionality, and convenience as the most crucial dimensions for SST quality. Further research is needed for a generalization of the result and to determine if the SSTQUAL scale is an instrument suitable for measuring SST quality in the Swedish banking sector.Självbetjäningstjänster, SST, gör det möjligt för kunden att interagera med en tjänst utan kontakt med en anställd. Denna teknik har flera fördelar för både kunder och företag och är ett kraftfullt verktyg för att uppnå långsiktig framgång. Kvaliten på en SST är avgörande för att uppnå en långsiktig framgång för företaget. Därför blir det viktigt att mäta kvaliten på en SST. Självbetjäningsteknik kvalitet skalan (SSTQUAL skalan) mäter SST-kvalitet i flera branscher. Utvecklarna av detta instrument, Lin och Hsieh uppmuntrade andra att göra ytterligare forskning på SSTQUAL skalan eftersom det är en kontinuerlig process som kan förändras över tid. Tidigare studier har visat att SSTQUAL skalan inom den Rumänska banksektorn har reviderats. Därför fokuserar denna studie att utvärdera hur servicekvalitet och SSTQUAL skalan passar i den Svenska banksektorn. Studien syftar till att identifiera hur skogs och lantbrukskunder i den Svenska banksektorn uppfattar SST-kvalitet. Arbetets struktur är baserat på ett specifikt fall i en svensk bank för att fånga hur kunden uppfattar SST-kvalitet inom dessa ramar och därmed uppnå målet med studien. Resultatet från denna studie visar att respondenterna uppfattar fem dimensioner, design, funktionalitet, säkerhet, anpassning och tillgänglighet som avgörande för kvaliten på en SST i den svenska banksektorn. Slutsatserna är att kunderna uppfattar design, funktionalitet och tillgänglighet som de mest avgörande dimensionerna för SST-kvalitet. Vidare forskning behövs för en generalisering av resultatet och för att avgöra om SSTQUAL skalan är ett instrument som passar för att mäta SST-kvalitet i den Svenska banksektorn

Austrian Social Security Database

The Austrian Social Security Database (ASSD) is a matched firm-worker data set, which records the labor market history of almost 11 million individuals from January 1972 to April 2007. Moreover, more than 2.2 million firms can be identified. The individual labor market histories are described in the follow- ing dimensions: very detailed daily labor market states and yearly earnings at the firm-worker level, together with a limited set of demographic characteris- tics. Additionally the ASSD provides some firm related information, such as geographical location and industry affiliation. This paper is a short description of this huge data base and intended for people using this data in their own empirical work.

Scattering amplitudes of massive Nambu-Goldstone bosons

Massive Nambu-Goldstone (mNG) bosons are quasiparticles whose gap is determined exactly by symmetry. They appear whenever a symmetry is broken spontaneously in the ground state of a quantum many-body system, and at the same time explicitly by the system's chemical potential. In this paper, we revisit mNG bosons and show that apart from their gap, symmetry also protects their scattering amplitudes. Just like for ordinary gapless NG bosons, the scattering amplitudes of mNG bosons vanish in the long-wavelength limit. Unlike for gapless NG bosons, this statement holds for any scattering process involving one or more external mNG states; there are no kinematic singularities associated with the radiation of a soft mNG boson from an on-shell initial or final state.Comment: 12 pages; v2: added discussion of the double-soft limit in response to the referee report; matches version published in PR

Banking on Snow: Bank Capital, Risk, and Employment

How does small-firm employment respond to exogenous labor productivity risk? We find that this depends on the capitalization of firms' local banks. The evidence comes from firms offering (quasi-) fixed employment to workers whose productivity depends on the weather. Weather risk reduces this employment, and the effect is stronger in regions where the regional banks have less equity capital. Bank capitalization also proxies for the extent to which the regional banks’ borrowers can obtain liquidity when the regions are hit by weather shocks. We argue that, as liquidity providers, well-capitalized banks support economic adaptation to climate change

Effects of power variation on cycle performance during simulated hilly time-trials

It has previously been shown that cyclists are unable to maintain a constant power output during cycle time-trials on hilly courses. The purpose of the present study is therefore to quantify these effects of power variation using a mathematical model of cycling performance. A hypothetical cyclist (body mass: 70 kg, bicycle mass: 10 kg) was studied using a mathematical model of cycling, which included the effects of acceleration. Performance was modelled over three hypothetical 40-km courses, comprising repeated 2.5-km sections of uphill and downhill with gradients of 1%, 3%, and 6%, respectively. Amplitude (5–15%) and distance (0.31–20.00 km) of variation were modelled over a range of mean power outputs (200–600 W) and compared to sustaining a constant power. Power variation was typically detrimental to performance; these effects were augmented as the amplitude of variation and severity of gradient increased. Varying power every 1.25 km was most detrimental to performance; at a mean power of 200 W, performance was impaired by 43.90 s (±15% variation, 6% gradient). However at the steepest gradients, the effect of power variation was relatively independent of the distance of variation. In contrast, varying power in parallel with changes in gradient improved performance by 188.89 s (±15% variation, 6% gradient) at 200 W. The present data demonstrate that during hilly time-trials, power variation that does not occur in parallel with changes in gradient is detrimental to performance, especially at steeper gradients. These adverse effects are substantially larger than those previously observed during flat, windless time-trials