Decadal trends in aerosol chemical composition at Barrow, Alaska: 1976–2008

Aerosol measurements at Barrow, Alaska during the past 30 years have identified the long range transport of pollution associated with Arctic Haze as well as ocean-derived aerosols of more local origin. Here, we focus on measurements of aerosol chemical composition to assess (1) trends in Arctic Haze aerosol and implications for source regions, (2) the interaction between pollution-derived and ocean-derived aerosols and the resulting impacts on the chemistry of the Arctic boundary layer, and (3) the response of aerosols to a changing climate. Aerosol chemical composition measured at Barrow, AK during the Arctic haze season is compared for the years 1976–1977 and 1997–2008. Based on these two data sets, concentrations of non-sea salt (nss) sulfate (SO<sub>4</sub><sup>=</sup>) and non-crustal (nc) vanadium (V) have decreased by about 60% over this 30 year period. Consistency in the ratios of nss SO<sub>4</sub><sup>=</sup>/ncV and nc manganese (Mn)/ncV between the two data sets indicates that, although emissions have decreased in the source regions, the source regions have remained the same over this time period. The measurements from 1997–2008 indicate that, during the haze season, the nss SO<sub>4</sub><sup>=</sup> aerosol at Barrow is becoming less neutralized by ammonium (NH<sub>4</sub><sup>+</sup>) yielding an increasing sea salt aerosol chloride (Cl<sup>−</sup>) deficit. The expected consequence is an increase in the release of Cl atoms to the atmosphere and a change in the lifetime of volatile organic compounds (VOCs) including methane. In addition, summertime concentrations of biogenically-derived methanesulfonate (MSA<sup>−</sup>) and nss SO<sub>4</sub><sup>=</sup> are increasing at a rate of 12 and 8% per year, respectively. Further research is required to assess the environmental factors behind the increasing concentrations of biogenic aerosol

Evaluation of competences at the community pharmacy settings

The General Level Framework (GLF) document provides a model to be used in evaluating and upgrading of pharmacists’ competences currently used in many countries. This study has several Objectives: To show the adaptation process of the GLF document to the Serbian pharmaceutical work practices and regulations; to illustrate the implementation of the GLF document; to evaluate and monitor the development of pharmacists’ competencies. Materials and Methods: The adaptation, analysis, validation and adjustment of the GLF document were conducted using the expert panel method. The implementation was conducted on a sample of pharmacists employed in Subotica Pharmacy chain. Later, the evaluation of the pharmacists’ competencies was performed at two observation points (at the beginning of the study and after 6 months) by the team of seven GLF members. Results and Discussion: The GLF document was reviewed by 14 members of the expert panel. During the content validation performed at the expert panel meeting, all competencies stated in the GLF document were rated according to their importance with an average grade of between 8.26 and 9.80 and thus reached a consensus regarding all 26 competencies. During the evaluation of the pharmacists’ competences, the greatest improvement after the second observation was noted in the “Patient consent” competency, followed by the “Drug history”, “The prescription is legal“, “Health needs”, “Provision of written information” and “Assessing outcomes of contributions” competencies. All the competencies in the GLF document were accepted for the implementation in the Subotica Pharmacy chain. Six of the competencies there was a significant improvement observed

A critical evaluation of the electronic surgical logbook

BACKGROUND: The Association of Surgeons of Great Britain and Ireland (ASGBI) devised the electronic surgical logbook (version 2.4) for higher trainees in General Surgery enabling trainees to compile a uniform data set of their operative and training experience. This is in use by higher surgical trainees (HST) in the United Kingdom. This logbook permits trainees to submit data centrally into a Regional Analysis Database (RAD). With the implementation of the European Working Time Directive (EWTD) there is need for reliable data to assess the effects of the directive on training. In order to draw meaningful conclusions from the database the quality of data needs to be validated. We critically analysed the RAD in the Yorkshire region for a one-year period. METHODS: The RAD from the ASGBI for the Yorkshire region was analysed. Data for the period 01/10/2002–30/09/2003 was identified and interrogated using Microsoft Excel (2000 version). The RAD was compared with information obtained from the Regional Surgical Advisor for Yorkshire with respect to hospitals, surgical consultants and HST's in the region during the study period. RESULTS: There were 13,755 operations entered for the study period. 579 corrections to the data had to be made (4.2%) and a further 1140 entries were deleted (8.2%). Following corrections and deletions 12,615 operative entries were available for analysis. Overall 12.5% of the data required either correction or exclusion from the database prior to analysis. CONCLUSION: The RAD has a large dataset useful to monitor and assess training. However, the quality of the data needs to be verified prior to use. Recommendations have been made to develop the ASGBI logbook, which would eventually translate to improved data reliability of the RAD

Probing a non-biaxial behavior of infinitely thin hard platelets

We give a criterion to test a non-biaxial behavior of infinitely thin hard platelets of $D_{2h}$ symmetry based upon the components of three order parameter tensors. We investigated the nematic behavior of monodisperse infinitely thin rectangular hard platelet systems by using the criterion. Starting with a square platelet system, and we compared it with rectangular platelet systems of various aspect ratios. For each system, we performed equilibration runs by using isobaric Monte Carlo simulations. Each system did not show a biaxial nematic behavior but a uniaxial nematic one, despite of the shape anisotropy of those platelets. The relationship between effective diameters by simulations and theoretical effective diameters of the above systems was also determined.Comment: Submitted to JPS

Development of planar pixel modules for the ATLAS high luminosity LHC tracker upgrade

The high-luminosity LHC will present significant challenges for tracking systems. ATLAS is preparing to upgrade the entire tracking system, which will include a significantly larger pixel detector. This paper reports on the development of large area planar detectors for the outer pixel layers and the pixel endcaps. Large area sensors have been fabricated and mounted onto 4 FE-I4 readout ASICs, the so-called quad-modules, and their performance evaluated in the laboratory and testbeam. Results from characterisation of sensors prior to assembly, experience with module assembly, including bump-bonding and results from laboratory and testbeam studies are presented

Finite to infinite steady state solutions, bifurcations of an integro-differential equation

We consider a bistable integral equation which governs the stationary solutions of a convolution model of solid--solid phase transitions on a circle. We study the bifurcations of the set of the stationary solutions as the diffusion coefficient is varied to examine the transition from an infinite number of steady states to three for the continuum limit of the semi--discretised system. We show how the symmetry of the problem is responsible for the generation and stabilisation of equilibria and comment on the puzzling connection between continuity and stability that exists in this problem

Influence of particle size and chemistry on the cloud nucleating properties of aerosols

International audienceThe ability of an aerosol particle to act as a cloud condensation nuclei (CCN) is a function of the size of the particle, its composition and mixing state, and the supersaturation of the cloud. In-situ data from field studies provide a means to assess the relative importance of these parameters. During the 2006 Texas Air Quality ? Gulf of Mexico Atmospheric Composition and Climate Study (TexAQS-GoMACCS), the NOAA RV Ronald~H.~Brown encountered a wide variety of aerosol types ranging from marine near the Florida panhandle to urban and industrial in the Houston-Galveston area. These varied sources provided an opportunity to investigate the role of aerosol sources, chemistry, and size in the activation of particles to form cloud droplets. Measurements were made of CCN concentrations, aerosol chemical composition in the size range relevant for particle activation, and aerosol size distributions. Variability in aerosol composition was parameterized by the mass fraction of Hydrocarbon-like Organic Aerosol (HOA) for particle diameters less than 200 nm (vacuum aerodynamic). The HOA mass fraction in this size range was lowest for marine aerosol and highest for aerosol sampled close to anthropogenic sources. Combining all data from the experiment reveals that composition (defined by HOA mass fraction) explains 40% of the variance in the critical diameter for particle activation at 0.44% supersaturation (S). Correlations between HOA mass fraction and aerosol mean diameter show that these two parameters are essentially independent of one another for this data set. We conclude that, based on the variability of the HOA mass fraction observed during TexAQS-GoMACCS, composition played a significant role in determining the fraction of particles that could activate to form cloud droplets. In addition, we estimate the error that results in calculated CCN concentrations if the HOA mass fraction is neglected (i.e., a fully soluble composition of (NH4)2SO4 is assumed) for the range of mass fractions and mean diameters observed during the experiment. This error is then related to the source of the aerosol. At 0.22 and 0.44% S, the error is considerable (>50%) for anthropogenic aerosol sampled near the source region as this aerosol had, on average, a high HOA mass fraction in the sub-200 nm diameter size range (vacuum aerodynamic). The error is lower for aerosol distant from anthropogenic source regions as it had a lower HOA mass fraction. Hence, the percent error in calculated CCN concentration is larger for organic-rich aerosol sampled near the source and smaller for aerosol sampled away from sources of anthropogenic particulate organic matter (POM)

Edge pixel response studies of edgeless silicon sensor technology for pixellated imaging detectors

Silicon sensor technologies with reduced dead area at the sensor's perimeter are under development at a number of institutes. Several fabrication methods for sensors which are sensitive close to the physical edge of the device are under investigation utilising techniques such as active-edges, passivated edges and current-terminating rings. Such technologies offer the goal of a seamlessly tiled detection surface with minimum dead space between the individual modules. In order to quantify the performance of different geometries and different bulk and implant types, characterisation of several sensors fabricated using active-edge technology were performed at the B16 beam line of the Diamond Light Source. The sensors were fabricated by VTT and bump-bonded to Timepix ROICs. They were 100 and 200 μ m thick sensors, with the last pixel-to-edge distance of either 50 or 100 μ m. The sensors were fabricated as either n-on-n or n-on-p type devices. Using 15 keV monochromatic X-rays with a beam spot of 2.5 μ m, the performance at the outer edge and corners pixels of the sensors was evaluated at three bias voltages. The results indicate a significant change in the charge collection properties between the edge and 5th (up to 275 μ m) from edge pixel for the 200 μ m thick n-on-n sensor. The edge pixel performance of the 100 μ m thick n-on-p sensors is affected only for the last two pixels (up to 110 μ m) subject to biasing conditions. Imaging characteristics of all sensor types investigated are stable over time and the non-uniformities can be minimised by flat-field corrections. The results from the synchrotron tests combined with lab measurements are presented along with an explanation of the observed effects

Transitioning in higher education: An exploration of psychological and contextual factors affecting student satisfaction

© 2017 UCU. In view of recent changes in the higher education sector, such as increased tuition fees, a greater focus has been placed on widening participation initiatives and monitoring student satisfaction. The aims of the current study were twofold: (1) to explore whether pre-entry programmes foster successful transition to higher education, and (2) to examine longitudinally the factors associated with course satisfaction. Eighty-eight first-year psychology students completed a questionnaire measuring academic self-efficacy, social identity and student satisfaction at the start (Time 1, November 2015) and end (Time 2, March 2016) of the academic year. Findings indicated that students who participated in a pre-entry programme reported higher academic self-efficacy and satisfaction compared to typical route students. Moreover, academic self-efficacy predicted student satisfaction at the start of the academic year, whereas in-group affect (a facet of social identity) predicted this at the end of the academic year. The current findings indicate that pre-entry programmes may have a positive impact on students’ sense of academic self-efficacy. On a more general level, the findings also suggest that academic self-efficacy and social identity may be key indicators of student satisfaction. This highlights the complexities of the concept of ‘student satisfaction’, and demonstrates the utility of examining multiple factors relating to student satisfaction across different time points