Anisotropic intrinsic spin relaxation in graphene due to flexural distortions

We propose an intrinsic spin scattering mechanism in graphene originated by the interplay of atomic spin-orbit interaction and the local curvature induced by flexural distortions of the atomic lattice. Starting from a multiorbital tight-binding Hamiltonian with spin-orbit coupling considered nonperturbatively, we derive an effective Hamiltonian for the spin scattering of the Dirac electrons due to flexural distortions. We compute the spin lifetime due to both flexural phonons and ripples and we find values in the microsecond range at room temperature. Interestingly, this mechanism is anisotropic on two counts. First, the relaxation rate is different for off-plane and in-plane spin quantization axis. Second, the spin relaxation rate depends on the angle formed by the crystal momentum with the carbon-carbon bond. In addition, the spin lifetime is also valley dependent. The proposed mechanism sets an upper limit for spin lifetimes in graphene and will be relevant when samples of high quality can be fabricated free of extrinsic sources of spin relaxation.

Thermal decomposition of the different particles size fractions of almond shells and olive stones. Thermal behaviour changes due to the milling processes

The aim of this study is to investigate the effect of particle size on the non-isothermal pyrolysis of almond shells (AS) and olive stones (OS) and to show possible differences in the composition of the different fractions obtained after milling and sieving. The results obtained from the study of different particle size of AS and OS samples show significant differences in the solid residue obtained and in the shape and overlapping degree of the peaks, especially with the smaller particle size. These differences can be due to different factors: (a) the amount of inorganic matter, which increases as particle size decreases, (b) heat and mass transfer processes, (c) different sample composition as a consequence of the milling process which may provoke changes in the structure and the segregation of the components (in addition to the ashes) increasingly changes the composition of the sample as the particle size decreases.

Trends in mortality due to motor vehicle traffic accident injuries between 1987 and 2011 in a Spanish region (Comunitat Valenciana)

Objective: To analyse the time evolution of the rates of mortality due to motor vehicle traffic accidents (MVTA) injuries that occurred among the general population of Comunitat Valenciana between 1987 and 2011, as well as to identify trend changes by sex and age group. Methods: An observational study of annual mortality trends between 1987 and 2011. We studied all deaths due to MVTA injuries that occurred during this period of time among the non-institutionalised population residing in Comunitat Valenciana (a Spanish Mediterranean region that had a population of 5,117,190 inhabitants in 2011). The rates of mortality due to MVTA injuries were calculated for each sex and year studied. These rates were standardised by age for the total population and for specific age groups using the direct method (age-standardised rate – ASR). Joinpoint regression models were used in order to detect significant trend changes. Additionally, the annual percentage change (APC) of the ASRs was calculated for each trend segment, which is reflected in statistically significant joinpoints. Results: For all ages, ASRs decrease greatly in both men and women (70% decrease between 1990 and 2011). In 1990 and 2011, men have rates of 36.5 and 5.2 per 100,000 men/year, respectively. In the same years, women have rates of 8.0 and 0.9 per 100,000 women/year, respectively. This decrease reaches up to 90% in the age group 15–34 years in both men and women. ASR ratios for men and women increased over time for all ages: this ratio was 3.9 in 1987; 4.6 in 1990; and 5.8 in 2011. For both men and women, there is a first significant segment (p < 0.05) with an increasing trend between 1987 and 1989–1990. After 1990, there are 3 segments with a significant decreasing APC (1990–1993, 1993–2005 and 2005–2011, in the case of men; and 1989–1996, 1999–2007 and 2007–2011, in the case of women). Conclusion: The risk of death due to motor vehicle traffic accidents injuries has decreased significantly, especially in the case of women, for the last 25 years in Comunitat Valenciana, mainly as of 2006. This may be a consequence of the road-safety measures that have been implemented in Spain and in Comunitat Valenciana since 2004. The economic crisis that this country has undergone since 2008 may have also been a contributing factor to this decrease. Despite the decrease, ASR ratios for men and women increased over time and it is still a high-risk cause of death among young men. It is thus important that the measures that helped decrease the risk of death are maintained and improved over time.

Non-spectral interferences due to the presence of sulfuric acid in inductively coupled plasma mass spectrometry

Results of a systematic study concerning non-spectral interferences from sulfuric acid containing matrices on a large number of elements in inductively coupled plasma–mass spectrometry (ICP-MS) are presented in this work. The signals obtained with sulfuric acid solutions of different concentrations (up to 5% w w− 1) have been compared with the corresponding signals for a 1% w w− 1− nitric acid solution at different experimental conditions (i.e., sample uptake rates, nebulizer gas flows and r.f. powers). The signals observed for 128Te+, 78Se+ and 75As+ were significantly higher when using sulfuric acid matrices (up to 2.2-fold for 128Te+ and 78Se+ and 1.8-fold for 75As+ in the presence of 5 w w-1 sulfuric acid) for the whole range of experimental conditions tested. This is in agreement with previously reported observations. The signal for 31P+ is also higher (1.1-fold) in the presence of sulfuric acid. The signal enhancements for 128Te+, 78Se+, 75As+ and 31P+ are explained in relation to an increase in the analyte ion population as a result of charge transfer reactions involving S+ species in the plasma. Theoretical data suggest that Os, Sb, Pt, Ir, Zn and Hg could also be involved in sulfur-based charge transfer reactions, but no experimental evidence has been found. The presence of sulfuric acid gives rise to lower ion signals (about 10–20% lower) for the other nuclides tested, thus indicating the negative matrix effect caused by changes in the amount of analyte loading of the plasma. The elemental composition of a certified low-density polyethylene sample (ERM-EC681K) was determined by ICP-MS after two different sample digestion procedures, one of them including sulfuric acid. Element concentrations were in agreement with the certified values, irrespective of the acids used for the digestion. These results demonstrate that the use of matrix-matched standards allows the accurate determination of the tested elements in a sulfuric acid matrix.

Wavefront-Guided Laser Treatment Using a High-Resolution Aberrometer to Measure Irregular Corneas: A Pilot Study

PURPOSE: To evaluate in a pilot study the visual, refractive, corneal topographic, and aberrometric changes after wavefront-guided LASIK or photorefractive keratectomy (PRK) using a high-resolution aberrometer to calculate the treatment for aberrated eyes. METHODS: Twenty aberrated eyes of 18 patients undergoing wavefront-guided LASIK or PRK using the VISX STARS4IR excimer laser and the iDesign aberrometer (Abbott Medical Optics, Inc., Santa Ana, CA) were enrolled in this prospective study. Three groups were differentiated: keratoconus post-CXL group including 11 keratoconic eyes (10 patients), post-LASIK group including 5 eyes (5 patients) with previous decentered LASIK treatments, and post-RK group including 4 eyes (3 patients) with previous radial keratotomy. Visual, refractive, contrast sensitivity, corneal topographic, and ocular aberrometric changes were evaluated during a 6-month follow-up. RESULTS: An improvement in uncorrected (UDVA) and corrected visual acuity (CDVA) associated with a reduction in the spherical equivalent was observed in the three groups, but was only statistically significant in the keratoconus post-CXL and post-LASIK groups (P ≤ .04). All eyes gained one or more lines of CDVA after surgery. Improvements in contrast sensitivity were observed in the three groups, but they were only statistically significant in the keratoconus post-CXL and post-LASIK groups (P ≤ .04). Regarding aberrations, a reduction was observed in trefoil aberrations in the keratoconus post-CXL group (P = .05) and significant reductions in higher-order and primary coma aberrations in the post-LASIK group (P = .04). CONCLUSIONS: Wavefront-guided laser enhancements using the evaluated platform seem to be safe and effective to restore the visual function in aberrated eyes.

A statement of the monies which have been paid, & of the debts which are still due to Thomas Adams formerly College Butler. 15 April 1794

Statement with list of creditors paid with cash from the student accounts.

A statement of the bills due to Thomas Adams, late Butler of Harvard College and the amount of their appropriations to discharge his debts, 1794

Statement with list of creditors owed funds. Verso is dated 1797, and includes list of cash paid out to creditors.

Under the veneer of decentralisation. Ukraine's modernisation efforts stall due to lack of local government reform. OSW Commentary No. 102, 2013-02-12

President Viktor Yanukovych and his Party of Regions have been repeating the pledge to decentralise power in Ukraine and to give local government a greater decision-making role ever since the party appeared on the Ukrainian political scene. The implementation of this reform is crucial both for the economic recovery of Ukraine’s regions and the overall modernisation efforts of the Ukrainian state. At present relations between central government and the regions are regulated by Soviet-era legislation that fails to address the modern-day challenges facing Ukraine. The political elite in the country, including the opposition, appear to have reached consensus on the importance of the decentralisation reform. The first attempts to implement changes in this area were made in the late 1990s, followed by a comprehensive reform programme developed between 2007 and 2009 by Yulia Tymoshenko’s government. In 2012, the Constitutional Assembly under the President of Ukraine appointed a team of experts who drafted a document detailing the reform of local government and the territorial organisation of power1. The document envisages the implementation of what effectively are two major reforms: (1) an administrative-territorial reform, which would help consolidate the fragmented administrative structure, creating larger and more economically self-sufficient administrative units, and (2) local government reform, focusing on creating clearly defined powers for local authorities with a view to securing government funding for specific tasks delegated from central government. Nonetheless, despite these measures, and in spite of the rhetoric coming from President Yanukovych and other members of the Party of Regions, it seems unlikely that the reform will be implemented in the foreseeable future. A series of concrete political decisions taken by the president over the past three years indicate that Yanukovych has not abandoned his plan to build a highly centralised political system. This in turn limits the capacity to govern of local authorities and further restricts the sources of funding for Ukraine’s regions. This apparent resistance to change stems from the fact that by implementing the proposed reforms, the president and his political allies would be forced to relinquish much of their control over the political processes taking place in the country and would have to free up the distribution of budgetary resources between Kyiv and the regions. The implementation of the reform within the specified timeframe (i.e. by 2015) is also unlikely due to the upcoming presidential election and the deteriorating economic situation in Ukraine. Without a comprehensive reform of local government, however, Ukraine will be unable to undertake effective modernisation measures, which are key for the socio-economic development of the country’s regions.

Life Is Getting Worse in ESS Data: Is This Due to Micro or Macro Factors? Bruges European Economic Research (BEER) Papers 28/November 2013

In order to evaluate the success of a society, measuring well-being might be a fruitful avenue. For a long time, governments have trusted economic measures, Gross Domestic Product (GDP) in particular, to assess their success. However GDP is only a limited measure of economic success, which is not enough to show whether policies implemented by governments have a positive perceived impact on the people they represent. This paper belongs to the studies of the relationship between measures of well-being and economic factors. More precisely, it tries to evaluate the decrease in happiness and life satisfaction that can be observed in European countries in the 2000-2010 decade. It asks whether this deterioration is mainly due to microeconomic factors, such as income and individual characteristics, or rather to environmental (macroeconomics) factors such as unemployment, inflation or income inequality. Such aggregate factors could impact individual happiness per se because they are related to the perception of an aggregate risk of unemployment or income fall. In order to strengthen this interpretation, this paper checks whether the type of social protection regime existing in different countries mediates the impact of macroeconomic volatility on individual well-being. To go further, adopting the classification of welfare regimes proposed by Esping-Andersen (1990), it verifies whether the decreasing pattern of subjective well-being varies across these regimes. This is partly due to the aggregate social protection expenditure. Hence, this paper brings some additional evidence to the idea that macroeconomic uncertainty has a cost in terms of well-being. More protective social regimes are able to reduce this cost. It also proposes an evaluation of the welfare cost of unemployment and inflation (in terms of happiness and life satisfaction), in each of the different social protection regimes. Finally different measures of well-being, i.e. cognitive, hedonic and eudaimonic, are used to confirm the above mentioned result.