bluuebunny/crossref_metadata_2025 huggingface dataset:
Views of the chairs of Scottish health boards on engagement with quality management and comparisons with English trusts
Authors: Bream E , Jha AK , Epstein AM , Black N
Published: October 2013

Objective: To describe the views of the chairs of Scottish health boards on the engagement of their boards with healthcare quality and to compare them with the views of the chairs of boards of English acute trusts. The focus of the Scottish Health Boards is on providing and commissioning care, while in England the acute trusts only provide care.

Methods: We mailed a questionnaire, based on one used in England, to the 14 health board chairs in NHS Scotland in January 2011. The results were compared with the results of a similar questionnaire given to English acute trust chairs in 2009.

Results: Most chairs in Scotland (67%) prioritised oversight of quality. Quality is considered at most Board meetings (92%), taking over 20% of time for 69% of chairs. Most boards have local quality targets and feedback quality data to staff. Compared with England, boards in Scotland meet less frequently and focus less on quality (shorter discussions, less frequent data review, fewer local targets) but they are more optimistic about their board’s performance.

Conclusions: Although most chairs of Scottish boards view quality as a priority, they pay less attention to it than chairs in England, possibly due to their additional role in commissioning care.
Reversible cerebral vasoconstriction syndrome
Authors: Lee R , Ramadan H , Bamford J
Published: October 2013

Reversible cerebral vasoconstriction syndrome (RCVS) is an underdiagnosed condition which usually presents as severe headache with or without neurological deficit. We report the case of a 55-year-old woman who presented with headache and multifocal intracerebral haemorrhage. We review the literature regarding the presentation, pathophysiology and management of RCVS and discuss how to differentiate it from cerebral vasculitis.
Working the night shift: a necessary time for training or a risk to health and safety?
Authors: Morrison I , Flower D , Hurley J , MacFadyen RJ
Published: October 2013

The European Working Time Directive (EWTD) limits excessive night shifts and restricts the working week to no more than 48 hours. The underlying rationale is to minimise the health risks to all workers. Here we debate the impact of night rotas for doctors-in-training on patient safety and medical education; when the EWTD was agreed these topics may not have been considered, either systematically or objectively. The impacts of diurnal rhythms on human functions affect all night workers, but the nature of rostered medical and surgical work has little precedent in other industries or even in the contracts of other healthcare staff. For example, rostered night duties need to be distinguished from permanent night shift work. On-call medical night work from training doctors is generally required for short periods and usually involves fewer patients. It is an important time in training, where clinical responsibility and decision-making can be matured in a supervised setting. To comply with the EWTD most hospitals have adopted rota patterns that aim to cover the clinical needs, while ensuring no doctor works for more than 48 hours in an average working week. To monitor this process longterm studies are necessary to evaluate effects on a doctor’s health and on patient care generally. The EWTD has also led to a loss of continuity of patient care; does this really matter?
Cutaneous allergy
Authors: McKay DA
Published: October 2013

Cutaneous allergy encompasses a broad spectrum of clinical presentations with complex underlying immunological mechanisms. Allergy may be considered to play a role in disorders that include atopic dermatitis, contact dermatitis, urticaria, angioedema, anaphylaxis and adverse drug reactions. The skin phenotypes associated with allergy are more commonly exhibited in non-allergic disease and so a high proportion of patients who consider themselves allergic in truth have other, nonallergic explanations for their presentation. Investigations may help to delineate those individuals who are more likely to have true allergy, but tests currently available have significant limitations and are open to easy misinterpretation. As a consequence, any investigations are best carried out by someone experienced in managing patients with potentially allergic disorders.
Management of hyperkalaemia
Authors: Maxwell AP , Linden K , O’Donnell S , Hamilton PK , McVeigh GE
Published: October 2013

Hyperkalaemia, an elevated extracellular fluid potassium concentration, is a common electrolyte disorder and is present in 1–10% of hospitalised patients. Elevated serum potassium concentrations are usually asymptomatic but may be associated with electrocardiogram (ECG) changes. Hyperkalaemia occasionally leads to life-threatening cardiac arrhythmias. Prompt recognition of this disorder, patient risk management and administration of appropriate treatment can prevent serious cardiac complications of hyperkalaemia. Further assessment of the underlying basis for hyperkalaemia usually reveals a problem with renal potassium excretion (rather than transcellular shift of potassium or excess potassium intake). Reduced potassium excretion is typically associated with decreased potassium secretion in the aldosterone-sensitive distal nephron of the kidney. Common causes for hyperkalaemia include kidney failure, limited delivery of sodium and water to the distal nephron and drugs that inhibit the renin-angiotensin-aldosterone system. Treatment of life-threatening hyperkalaemia (particularly those patients with ECG changes) involves administration of intravenous calcium salts to stabilise the resting cardiac membrane potential. The potassium concentration can be lowered by administration of intravenous insulin combined with an infusion of glucose to stimulate intracellular uptake of potassium. Nebulised β-2 adrenoceptor agonists can augment the effects of intravenous insulin and glucose pending more definitive management of the recurrent hyperkalaemia risk. Additional management steps include stopping further potassium intake and careful review of prescribed drugs that may be adversely affecting potassium homeostasis. Changes to prescribing systems and an agreed institutional protocol for management of hyperkalaemia can improve patient safety for this frequently encountered electrolyte disorder.
The history of osteoporosis: why do Egyptian mummies have porotic bones?
Authors: Stride PJO , Patel N , Kingston D
Published: October 2013

Paleopathologists have identified osteoporosis in ancient skeletons and modern physicians and scientists have identified risk factors for osteoporosis today, but they are not clearly linked, making it more difficult to clarify the causes of osteoporosis in the past. The evidence for osteoporosis in the remote past, its causes, and the management of this disease is reviewed in the light of evolving and improving diagnostic modalities, more precise definitions, and the recent rapid expansion of therapeutic options. While the specific effects of parity and lactation on the development of osteoporosis are still not entirely clear, duration of reproductive span and age at first pregnancy appear to be significant predisposing factors.
An explicit study of aerosol mass conversion and its parameterization in warm rain formation of cumulus clouds
Authors: Sun J. , Fen J. , Ungar R. K.
Published: October 2013

Abstract. The life time of atmospheric aerosols is highly affected by in-cloud scavenging processes. Aerosol mass conversion from aerosols embedded in cloud droplets into aerosols embedded in raindrops is a pivotal pathway for wet removal of aerosols in clouds. The aerosol mass conversion rate in the bulk microphysics parameterizations is always assumed to be linearly related to the precipitation production rate, which includes the cloud water autoconversion rate and the cloud water accretion rate. The ratio of the aerosol mass concentration conversion rate to the cloud aerosol mass concentration has typically been considered to be the same as the ratio of the precipitation production rate to the cloud droplet mass concentration. However, the mass of an aerosol embedded in a cloud droplet is not linearly proportional to the mass of the cloud droplet. A simple linear relationship cannot be drawn between the precipitation production rate and the aerosol mass concentration conversion rate. In this paper, we studied the evolution of aerosol mass concentration conversion rates in a warm rain formation process with a 1.5-dimensional non-hydrostatic convective cloud and aerosol interaction model in the bin microphysics. We found that the ratio of the aerosol mass conversion rate to the cloud aerosol mass concentration can be statistically expressed by the ratio of the precipitation production rate to the cloud droplet mass concentration with an exponential function. We further gave some regression equations to determine aerosol conversions in the warm rain formation under different threshold radii of raindrops and different aerosol size distributions.
The Greenhouse Gas Climate Change Initiative (GHG-CCI): comparative validation of GHG-CCI SCIAMACHY/ENVISAT and TANSO-FTS/GOSAT CO2 and CH4 retrieval algorithm products with measurements from the TCCON network
Authors: Dils B. , Buchwitz M. , Reuter M. , Schneising O. , Boesch H. , Parker R. , Guerlet S. , Aben I. , Blumenstock T. , Burrows J. P. , Butz A. , Deutscher N. M. , Frankenberg C. , Hase F. , Hasekamp O. P. , Heymann J. , De Mazière M. , Notholt J. , Sussmann R. , Warneke T. , Griffith D. , Sherlock V. , Wunch D.
Published: October 2013

Abstract. Column-averaged dry-air mole fractions of carbon dioxide and methane have been retrieved from spectra acquired by the TANSO-FTS and SCIAMACHY instruments on board GOSAT and ENVISAT using a range of European retrieval algorithms. These retrievals have been compared with data from ground-based high-resolution Fourier Transform Spectrometers (FTS) from the Total Carbon Column Observing Network (TCCON). The participating algorithms are the Weighting Function Modified Differential Optical Absorption Spectroscopy (DOAS) algorithm (WFMD, University of Bremen), the Bremen Optimal Estimation DOAS algorithm (BESD, University of Bremen), the Iterative Maximum A Posteriori DOAS (IMAP, Jet Propulsion Laboratory (JPL) and Netherlands Institute for Space Research algorithm (SRON)), the proxy and full-physics versions of SRON's RemoTeC algorithm (SRPR and SRFP respectively) and the proxy and full-physics versions of the University of Leicester's adaptation of the OCO (Orbiting Carbon Observatory) algorithm (OCPR and OCFP respectively). The goal of this algorithm inter-comparison was to identify strengths and weaknesses of the various so-called Round Robin data sets generated with the various algorithms so as to determine which of the competing algorithms would proceed to the next round of the European Space Agency's (ESA) Greenhouse Gas Climate Change Initiative (GHG-CCI) project, which is the generation of the so-called Climate Research Data Package (CRDP), which is the first version of the Essential Climate Variable (ECV) "Greenhouse Gases" (GHG). For CO2, all algorithms reach the precision requirements for inverse modelling (< 8 ppb), with only WFMD having a lower precision (4.7 ppm) than the other algorithm products (2.4–2.5 ppm). When looking at the seasonal relative accuracy (SRA, variability of the bias in space and time), none of the algorithms have reached the demanding < 0.5 ppm threshold. For CH4, the precision for both SCIAMACHY products (50.2 ppb for IMAP and 76.4 ppb for WFMD) fail to meet the < 34 ppb threshold, but note that this work focusses on the period after the 2005 SCIAMACHY detector degradation. The GOSAT XCH4 precision ranges between 18.1 and 14.0 ppb. Looking at the SRA, all GOSAT algorithm products reach the < 10 ppm threshold (values ranging between 5.4 and 6.2 ppb). For SCIAMACHY, IMAP and WFMD have a SRA of 17.2 ppb and 10.5 ppb respectively.
Multiple stressors of ocean ecosystems in the 21st century: projections with CMIP5 models
Authors: Bopp L. , Resplandy L. , Orr J. C. , Doney S. C. , Dunne J. P. , Gehlen M. , Halloran P. , Heinze C. , Ilyina T. , Séférian R. , Tjiputra J. , Vichi M.
Published: October 2013

Abstract. Ocean ecosystems are increasingly stressed by human-induced changes of their physical, chemical and biological environment. Among these changes, warming, acidification, deoxygenation and changes in primary productivity by marine phytoplankton can be considered as four of the major stressors of open ocean ecosystems. Due to rising atmospheric CO2 in the coming decades, these changes will be amplified. Here, we use the most recent simulations performed in the framework of the Coupled Model Intercomparison Project 5 to assess how these stressors may evolve over the course of the 21st century. The 10 Earth system models used here project similar trends in ocean warming, acidification, deoxygenation and reduced primary productivity for each of the IPCC's representative concentration pathways (RCPs) over the 21st century. For the "business-as-usual" scenario RCP8.5, the model-mean changes in the 2090s (compared to the 1990s) for sea surface temperature, sea surface pH, global O2 content and integrated primary productivity amount to +2.73 (±0.72) °C, −0.33 (±0.003) pH unit, −3.45 (±0.44)% and −8.6 (±7.9)%, respectively. For the high mitigation scenario RCP2.6, corresponding changes are +0.71 (±0.45) °C, −0.07 (±0.001) pH unit, −1.81 (±0.31)% and −2.0 (±4.1)%, respectively, illustrating the effectiveness of extreme mitigation strategies. Although these stressors operate globally, they display distinct regional patterns and thus do not change coincidentally. Large decreases in O2 and in pH are simulated in global ocean intermediate and mode waters, whereas large reductions in primary production are simulated in the tropics and in the North Atlantic. Although temperature and pH projections are robust across models, the same does not hold for projections of subsurface O2 concentrations in the tropics and global and regional changes in net primary productivity. These high uncertainties in projections of primary productivity and subsurface oxygen prompt us to continue inter-model comparisons to understand these model differences, while calling for caution when using the CMIP5 models to force regional impact models.
Influence of temperature and CO2 on the strontium and magnesium composition of coccolithophore calcite
Authors: Müller M. N. , Lebrato M. , Riebesell U. , Barcelos e Ramos J. , Schulz K. G. , Blanco-Ameijeiras S. , Sett S. , Eisenhauer A. , Stoll H. M.
Published: October 2013

Abstract. Marine calcareous sediments provide a fundamental basis for paleoceanographic studies aiming to reconstruct past oceanic conditions and understand key biogeochemical element cycles. Calcifying unicellular phytoplankton (coccolithophores) are a major contributor to both carbon and calcium cycling by photosynthesis and the production of calcite (coccoliths) in the euphotic zone and the subsequent long-term deposition and burial into marine sediments. Here we present data from controlled laboratory experiments on four coccolithophore species and elucidate the relation between the divalent cation (Sr, Mg and Ca) partitioning in coccoliths and cellular physiology (growth, calcification and photosynthesis). Coccolithophores were cultured under different seawater temperature and carbonate chemistry conditions. The partition coefficient of strontium (DSr) was positively correlated with both carbon dioxide (pCO2) and temperature but displayed no coherent relation to particulate organic and inorganic carbon production rates. Furthermore, DSr correlated positively with cellular growth rates when driven by temperature but no correlation was present when changes in growth rates were pCO2-induced. The results demonstrate the complex interaction between environmental forcing and physiological control on the strontium partitioning in coccolithophore calcite. The partition coefficient of magnesium (DMg) displayed species-specific differences and elevated values under nutrient limitation. No conclusive correlation between coccolith DMg and temperature was observed but pCO2 induced a rising trend in coccolith DMg. Interestingly, the best correlation was found between coccolith DMg and chlorophyll a production suggesting that chlorophyll a and calcite associated Mg originate from the same intracellular pool. These results give an extended insight into the driving factors that lead to variations in the coccolith Mg / Ca ratio and can be used for Sr / Ca and Mg / Ca paleoproxy calibration.
Forest NEP is significantly driven by previous year's weather
Authors: Zielis S. , Etzold S. , Zweifel R. , Eugster W. , Haeni M. , Buchmann N.
Published: October 2013

Abstract. Understanding the response of forest net ecosystem productivity (NEP) to environmental drivers under climate change is highly relevant for predictions of annual forest carbon (C) flux budgets. Modeling annual forest NEP with soil–vegetation–atmosphere transfer models (SVATs), however, remains challenging due to unknown responses of forests to weather of the previous year. In this study, we addressed the influence of previous year's weather on the inter-annual variability of NEP for a subalpine spruce forest in Switzerland. Analysis of long-term (1997–2011) eddy covariance measurements showed that the Norway spruce forest Davos Seehornwald was a consistent sink for atmospheric CO2, sequestering 210 ± 88 g C m−2 per year on average. Previous year's weather strongly affected inter-annual variability of NEP, increasing the explained variance in linear models to 53% compared to 20% without previous year's weather. Thus, our results highlight the need to consider previous year's weather in modeling annual C budgets of forests. Furthermore, soil temperature in the current year's spring played a major role controlling annual NEP, mainly by influencing gross primary productivity early in the year, with spring NEP accounting for 56% of annual NEP. Consequently, we expect an increase in net CO2 uptake with future climate warming, as long as no other resources become limiting.
Cumulated insolation: a simple explanation of Milankovitch's forcing on climate changes
Authors: Marra F.
Published: October 2013

Abstract. The occurrence of the sudden melting of the ice sheets during the glacial terminations is explained in this paper as the consequence of the combined role of the minima and the maxima of mean summer insolation on the Northern Hemisphere, providing a new contribution to understand the mechanisms ruling glacial forcing. Indeed, no satisfactory answer has been provided so far to the question why one specific maximum, after a series of consecutive maxima of insolation, has the potentiality to trigger a deglaciation. The explanation proposed in this paper accounts for a pre-conditioning factor, represented by "mild" (warmer) minimum, followed by a sufficiently warm maximum as the conditions that cause the end of a glacial cycle. These conditions are realized whenever the sum of the values of each consecutive minima and maxima ("cumulated insolation") on the curve of mean summer insolation at 65° N exceeds 742 Watt m−2. The comparison of the succession of these cumulated insolation values with the astronomically tuned Oxygen isotopes record provides a satisfactory match with the occurrence of all the glacial terminations in the last 800 ka.
Understanding the performance of the FLake model over the African Great Lakes
Authors: Thiery W. , Martynov A. , Darchambeau F. , Descy J.-P. , Plisnier P.-D. , Sushama L. , van Lipzig N. P. M.
Published: October 2013

Abstract. The ability of the one-dimensional lake model FLake to represent the mixolimnion temperatures for tropical conditions was tested for three locations in East Africa: Lake Kivu, Lake Tanganyika's northern and southern basins. Meteorological observations from surrounding Automatic Weather Stations were corrected and used to drive FLake, whereas a comprehensive set of water temperature profiles served to evaluate the model at each site. Careful forcing data correction and model configuration allowed to reproduce the observed mixed layer seasonality at Lake Kivu and Lake Tanganyika (northern and southern basins), with correct representation of both the mixed layer depth and temperature structure. At Lake Kivu, mixolimnion temperatures predicted by FLake were found sensitive both to minimal variations in the external parameters (lake depth and water transparency) as to small changes in the meteorological driving data, in particular wind velocity. In each case, small modifications may already lead to a regime switch from the correctly represented seasonal mixed layer deepening to either completely mixed (down to the model lake bottom) or permanently stratified (from ~10 m downwards) conditions. In contrast, model temperatures are found robust close to the surface, with acceptable predictions of near-surface water temperatures even when the seasonal mixing regime is not reproduced. FLake can thus be a suitable tool to parameterize tropical lake water surface temperatures within atmospheric prediction models, but may be less appropriate, in its current form, to study complex limnological processes within tropical lakes. Furthermore, a study of different initial conditions showed that for tropical lakes lacking reliable initial data, a fully mixed, artificially warm initialisation is to be preferred, but only if the model is allowed to spin up until convergence is reached. Finally, FLake was used to attribute the seasonal mixing cycle at Lake Kivu to variations in the near-surface meteorological conditions. It was found that the annual mixing down to 60 m during the main dry season is primarily due to enhanced lake evaporation and secondarily due to the decreased incoming long wave radiation, both causing a significant heat loss from the lake surface and associated mixolimnion cooling.
Ensemble initialization of the oceanic component of a coupled model through bred vectors at seasonal-to-interannual time scales
Authors: Baehr J. , Piontek R.
Published: October 2013

Abstract. We evaluate the ensemble spread at seasonal-to-interannual time scales for two perturbation techniques implemented into the ocean component of a coupled model: (1) lagged initial conditions as commonly used for decadal predictions, (2) bred vectors as commonly used for weather and seasonal forecasting. We show that relative to an uninitialized reference simulation the implementation for bred vectors can improve the ensemble spread compared to lagged initialization at time scales from one months up to three years. As bred vectors have so far mostly been used at short time scales, we initially focus on the implementation of the bred vectors into the ocean component. We introduce a depth-dependent vertical rescaling norm, accounting for the vertical dependence of the variability, and extending the commonly used upper-ocean rescaling norm to the full water column. We further show that it is sufficient for the (sub-surface) ocean to breed temperature and salinity (i.e., scalar quantities), and rely on the governing physics to carry the temperature and salinity perturbations to the flow field. Using these bred vectors with a rescaling interval of 12 months, we initialize hindcast simulations and compare them to hindcast simulations initialized with lagged initial conditions. We quantify the ensemble spread by analyzing Talagrand diagrams and spread-error ratios. For both temperature and salinity, the lagged initialized ensemble is particularly under-dispersive for the first few months of predictable lead time. The ensemble initialized with bred vectors improves the spread for temperature and salinity for the 0–700 m and 1000–3500 m means, compared to the lagged ensemble at lead times of several months to one year. As the lead time increases to years, the differences between the two ensemble initialization techniques becomes more difficult to discern. While the results need to be confirmed in an initialized framework, the present analysis represents a first step towards an improved ensemble generation at the transition from seasonal-to-interannual time scales, in particular at lead times up to one year.
Integrated hydrological modeling of the North China Plain and implications for sustainable water management
Authors: Qin H. , Cao G. , Kristensen M. , Refsgaard J. C. , Rasmussen M. O. , He X. , Liu J. , Shu Y. , Zheng C.
Published: October 2013

Abstract. Groundwater overdraft has caused fast water level decline in the North China Plain (NCP) since the 1980s. Although many hydrological models have been developed for the NCP in the past few decades, most of them deal only with the groundwater component or only at local scales. In the present study, a coupled surface water–groundwater model using the MIKE SHE code has been developed for the entire alluvial plain of the NCP. All the major processes in the land phase of the hydrological cycle are considered in the integrated modeling approach. The most important parameters of the model are first identified by a sensitivity analysis process and then calibrated for the period 2000–2005. The calibrated model is validated for the period 2006–2008 against daily observations of groundwater heads. The simulation results compare well with the observations where acceptable values of root mean square error (RMSE) (most values lie below 4 m) and correlation coefficient (R) (0.36–0.97) are obtained. The simulated evapotranspiration (ET) is then compared with the remote sensing (RS)-based ET data to further validate the model simulation. The comparison result with a R2 value of 0.93 between the monthly averaged values of simulated actual evapotranspiration (AET) and RS AET for the entire NCP shows a good performance of the model. The water balance results indicate that more than 70% of water leaving the flow system is attributed to the ET component, of which about 0.25% is taken from the saturated zone (SZ); about 29% comes from pumping, including irrigation pumping and non-irrigation pumping (net pumping). Sustainable water management analysis of the NCP is conducted using the simulation results obtained from the integrated model. An effective approach to improve water use efficiency in the NCP is by reducing the actual ET, e.g. by introducing water-saving technologies and changes in cropping.
Hydrologic impact of climate change on Murray Hotham catchment of Western Australia: a projection of rainfall-runoff for future water resources planning
Authors: Islam S. A. , Bari M. A. , Anwar A. H. M. F.
Published: October 2013

Abstract. Reduction of rainfall and runoff in recent years across South West Western Australia (SWWA) has drawn attention about climate change impact on water resources and its availability in this region. In this paper, hydrologic impact of climate change on Murray Hotham catchment in SWWA is investigated using multi-model ensemble approach. The Land Use Change Incorporated Catchment (LUCICAT) model was used for hydrologic modelling. Model calibration was performed using (5 km) grid rainfall data from Australian Water Availability Project (AWAP). Downscaled and bias corrected rainfall data from 11 General Circulation Models (GCMs) for Intergovernmental Panel on Climate Change (IPCC) emission scenarios A2 and B1 was used in LUCICAT model to derive rainfall and runoff scenarios for 2046–2065 (mid this century) and 2081–2100 (late this century). The results of climate scenarios were compared with observed past (1961–1980) climate. The mean annual rainfall averaged over the catchment during recent time (1981–2000) was reduced by 2.3% with respect to observed past (1961–1980) and resulting runoff reduction was found 14%. Compared to the past, the mean annual rainfall reductions, averaged over 11 ensembles and over the period for the catchment for A2 scenario are 13.6 and 23.6% for mid and late this century respectively while the corresponding runoff reductions are 36 and 74%. For B1 scenario, the rainfall reductions were 11.9 and 11.6% for mid and late this century and corresponding runoff reductions were 31 and 38%. Spatial distribution of rainfall and runoff changes showed that the rate of changes were higher in high rainfall part compared to the low rainfall part. Temporal distribution of rainfall and runoff indicate that high rainfall in the catchment reduced significantly and further reductions are projected resulting significant runoff reductions. A catchment scenario map has been developed through plotting decadal runoff reduction against corresponding rainfall reduction at four gauging stations for observed and projected period. This could be useful for planning future water resources in the catchment. Projection of rainfall and runoff made based on the GCMs varied significantly for the time periods and emission scenarios. Hence, considerable uncertainty involved in this study though ensemble mean was used to explain the findings.
Sulfur dioxide emissions from Papandayan and Bromo, two Indonesian volcanoes
Authors: Bani P. ,   Surono, Hendrasto M. , Gunawan H. , Primulyana S.
Published: October 2013

Abstract. Indonesia hosts 79 active volcanoes, representing 14% of all active volcanoes worldwide. However, little is known about their SO2 contribution into the atmosphere, due to isolation and access difficulties. Existing SO2 emission budgets for the Indonesian archipelago are based on extrapolations and inferences as there is a considerable lack of field assessments of degassing. Here, we present the first SO2 flux measurements using differential optical absorption spectroscopy (DOAS) for Papandayan and Bromo, two of the most active volcanoes in Indonesia. Results indicate mean SO2 emission rates of 1.4 t d−1 from the fumarolic activity of Papandayan and more than 22–32 t d−1 of SO2 released by Bromo during a declining eruptive phase. These DOAS results are very encouraging and pave the way for a better evaluation of Indonesian volcanic emissions.
3D-VAR multilayer assimilation of X-band SAR data into a detailed snowpack model
Authors: Phan X. V. , Ferro-Famil L. , Gay M. , Durand Y. , Dumont M. , Morin S. , Allain S. , D'Urso G. , Girard A.
Published: October 2013

Abstract. We introduce a variational data assimilation scheme to assimilate X-band Synthetic Aperture Radar (SAR) data into a snowpack evolution model. The structure properties of a snowpack, such as snow density and grain optical diameter of each layer, are simulated over a period of time by the snow metamorphism model Crocus, fed by the local reanalysis SAFRAN at a French alpine location. These parameters are used as inputs of an Electromagnetic Backscattering Model (EBM) based on Dense Media Radiative Transfer (DMRT) theory, which calculates the simulated total backscattering coefficient. Next, 3D-VAR data assimilation is implemented in order to minimize the discrepancies between model simulations and observations obtained from SAR acquisitions, by modifying the parameters of a multilayer snowpack calculated by Crocus. The algorithm then reinitializes Crocus with the optimized snowpack structure properties, and therefore allows it to continue the simulation of snowpack evolution where adjustments based on remote sensing data has been taken into account. Results obtained using TerraSAR-X acquisitions on Argentière Glacier (Mont-Blanc massif, French Alps) show the high potential of this method for improving snow cover simulation.
COOPERATIVE EFFECTS OF EPOXIDE FUNCTIONAL GROUPS ON NATURAL RUBBER AND SILANE COUPLING AGENTS ON REINFORCING EFFICIENCY OF SILICA
Authors: Kaewsakul W. , Sahakaro K. , Dierkes W. K. , Noordermeer J. W. M.
Published: October 2013

Polar functionality attached onto natural rubber has a significant impact on the reinforcing efficiency of silica. Parallel studies involving various levels of epoxidation on natural rubber (ENR) in the absence of bis-(triethoxysilylpropyl) tetrasulfide (TESPT) coupling agent, as well as a combination of ENRs with different loadings of TESPT, provide a better understanding of the various factors that influence the properties of silica-filled ENR compounds. Based on the overall properties, the best possible combination to optimize processability, to reduce filler–filler interaction, and improve vulcanization rate as well as vulcanizate properties, is to use ENR with an epoxide content in the range of 20–30 mol%, together with a small portion of TESPT, that is, 2–4 wt% relative to the silica content. This leads to a reduction of approximately 60–80% of TESPT when compared with the conventional NR compounds, where the optimal loading of TESPT was 9.0 wt% relative to the silica content.
PREDICTION OF ROLLING RESISTANCE FOR TRUCK BUS RADIAL TIRES WITH NANOCOMPOSITE BASED TREAD COMPOUNDS USING FINITE ELEMENT SIMULATION
Authors: Ghosh Sarat , Sengupta Ranjan A. , Kaliske Michael
Published: October 2013

Tire rolling resistance (RR) is a key performance index in the tire industry that addresses environmental concerns. Reduction of tire rolling resistance is a critical part of lowering fuel consumption, which could be achieved by changing both design and compound formulation. The major challenge is availability of a suitable software code to evaluate RR of tires using nonlinear viscoelastic properties of rubber. We developed a rolling resistance code and used it to predict rolling resistance of truck bus radial tires with nanocomposite based tread compounds. The energy dissipation in the tire is evaluated using the product of elastic strain energy and loss tangent of materials through post-processing using the rolling resistance code developed in this work. The elastic strain energy is obtained through steady state rolling simulation of tires using commercial software. The loss tangent versus strains at two reference temperatures is measured in the laboratory using a dynamic mechanical thermal analyzer. A temperature equation is developed to incorporate the effect of temperature on loss energy. Good correlation of rolling resistance is observed between simulation and experimental results. Nanocomposites used in this study are prepared based on natural rubber and polybutadiene rubber blends with either organoclay and carbon black or organoclay and silica dual filler system. Carboxylated nitrile rubber, a polar rubber, is used as a compatibilizer to facilitate the clay dispersion in the rubber matrix. Compared with general carbon black or silica tread compounds, substantial improvement of rolling resistance is predicted by finite element simulation with nanocomposite based tread compounds containing dual fillers.
The Posterior Epidural Ligaments: A Cadaveric and Histological Investigation in the Lumbar Region
Authors: Connor M. J. , Nawaz S. , Prasad V. , Mahir S. , Rattan R. , Bernard J. , Adds P. J.
Published: October 2013

Purpose. Incidental durotomy is a relatively common complication for patients undergoing posterior spinal surgery. Delineating anatomical variants in the posterior lumbar spinal canal is crucial in reducing future rates of incidental durotomy. Materials and Methods. The ligamentous attachments between the dura mater and ligamentum flavum in the lumbar region of 17 soft-fixed cadavers were investigated. The lumbar vertebral columns were removed, and cross-sectional dissection was performed at levels L1-S1. Anterior retraction of the dorsal dura mater identified attachments between the dorsal surface of the dura mater and the ligamentum flavum. Histological staining of the ligamentous attachments was carried out with hematoxylin and eosin (H&E) and elastic van Gieson (EVG). Results. Posterior epidural ligaments were present in 9 (52.9%) cadavers. Nine (9) separate ligaments were identified in these cadavers, with 3 (33.3%) at L3/L4, 5 (55.5%) at L4/L5, and 1 (11.1%) at L5/S1. Histology confirmed the presence of poorly differentiated collagen-based connective tissue, distinct from the normal anatomy. Conclusions. This study confirms the presence of multiple dorsomedial posterior epidural ligaments at the main sites for posterior spinal surgery (L3-S1). An intraoperative awareness of the variability of such connections may be an important step in reducing static rates of incidental durotomy.
Classification and Approximate Functional Separable Solutions to the Generalized Diffusion Equations with Perturbation
Authors: Ji Fei-Yu , Zhang Shun-Li
Published: October 2013

In this paper, the generalized diffusion equation with perturbation ut = A(u;ux)uII+eB(u;ux) is studied in terms of the approximate functional variable separation approach. A complete classification of these perturbed equations which admit approximate functional separable solutions is presented. Some approximate solutions to the resulting perturbed equations are obtained by examples.
Spatial and Temporal Aspects of Rurality of the Electoral Support for Slovak Political Parties in Statewide and Regional Context in the Period of 1998–2010
Authors: Plešivčák Martin
Published: October 2013

Voting preferences of electorates traditionally split along various structural cleavages in of society, including the urban-rural dimension. The intensity of both the similarity and divergence in voting decisions of inhabitants living in towns and cities on one hand, and in the countryside on the other, show varying rates of (in)stability, not only over time, but also in the spatial context, depending on the socio-economic, political, and historical predispositions of the country and its territorial units. The cardinal ambitions of this paper is both to evaluate the profile of urban-rural voter preferences of the main political parties on the Slovak political scene during the period of 1998-2010 at the national as well as at the regional level, and to reveal the socio-spatial mosaic in the electoral choices of people living in urban and rural environments in different parts of Slovakia using tools of cartographic interpretation.
Using computer-assisted learning to engage diverse learning styles in understanding business management principles
Authors: Frost Mary E. , Derby Dustin C. , Haan Andrea G.
Published: October 2013

Objective

Changes in small business and insurance present challenges for newly graduated chiropractors. Technology that reaches identified, diverse learning styles may assist the chiropractic student in business classes to meet course outcomes better. Thus, the purpose of our study is to determine if the use of technology-based instructional aids enhance students' mastery of course learning outcomes.

Methods

Using convenience sampling, 86 students completed a survey assessing course learning outcomes, learning style, and the helpfulness of lecture and computer-assisted learning related to content mastery. Quantitative analyses occurred.

Results

Although respondents reported not finding the computer-assisted learning as helpful as the lecture, significant relationships were found between pre- and post-assisted learning measures of the learning outcomes 1 and 2 for the visual and kinesthetic groups. Surprisingly, however, all learning style groups exhibited significant pre- and post-assisted learning appraisal relationships with learning outcomes 3 and 4.

Conclusion

While evidence exists within the current study of a relationship between students' learning of the course content corollary to the use of technologic instructional aids, the exact nature of the relationship remains unclear.
Diffusion‐weighted imaging and diagnosis of transient ischemic attack
Authors: Brazzelli Miriam , Chappell Francesca M. , Miranda Hector , Shuler Kirsten , Dennis Martin , Sandercock Peter A. G. , Muir Keith , Wardlaw Joanna M.
Published: October 2013

Objective

Magnetic resonance (MR) diffusion‐weighted imaging (DWI) is sensitive to small acute ischemic lesions and might help diagnose transient ischemic attack (TIA). Reclassification of patients with TIA and a DWI lesion as “stroke” is under consideration. We assessed DWI positivity in TIA and implications for reclassification as stroke.

Methods

We searched multiple sources, without language restriction, from January 1995 to July 2012. We used PRISMA guidelines, and included studies that provided data on patients presenting with suspected TIA who underwent MR DWI and reported the proportion with an acute DWI lesion. We performed univariate random effects meta‐analysis to determine DWI positive rates and influencing factors.

Results

We included 47 papers and 9,078 patients (range = 18–1,693). Diagnosis was by a stroke specialist in 26 of 47 studies (55%); all studies excluded TIA mimics. The pooled proportion of TIA patients with an acute DWI lesion was 34.3% (95% confidence interval [CI] = 30.5–38.4, range = 9–67%; I2 = 89.3%). Larger studies (n > 200) had lower DWI‐positive rates (29%; 95% CI = 23.2–34.6) than smaller (n < 50) studies (40.1%; 95% CI = 33.5–46.6%; p = 0.035), but no other testable factors, including clinician speciality and time to scanning, reduced or explained the 7‐fold DWI‐positive variation.

Interpretation

The commonest DWI finding in patients with definite TIA is a negative scan. Available data do not explain why ⅔ of patients with definite specialist‐confirmed TIA have negative DWI findings. Until these factors are better understood, reclassifying DWI‐positive TIAs as strokes is likely to increase variance in estimates of global stroke and TIA burden of disease. ANN NEUROL 2014;75:67–76
Catalytic Functionalization of C(sp2)H and C(sp3)H Bonds by Using Bidentate Directing Groups
Authors: Rouquet Guy , Chatani Naoto
Published: October 2013

CH bonds are ubiquitous in organic compounds. It would, therefore, appear that direct functionalization of substrates by activation of CH bonds would eliminate the multiple steps and limitations associated with the preparation of functionalized starting materials. Regioselectivity is an important issue because organic molecules can contain a wide variety of CH bonds. The use of a directing group can largely overcome the issue of regiocontrol by allowing the catalyst to come into proximity with the targeted CH bonds. A wide variety of functional groups have been evaluated for use as directing groups in the transformation of CH bonds. In 2005, Daugulis reported the arylation of unactivated C(sp3)H bonds by using 8‐aminoquinoline and picolinamide as bidentate directing groups, with Pd(OAc)2 as the catalyst. Encouraged by these promising results, a number of transformations of CH bonds have since been developed by using systems based on bidentate directing groups. In this Review, recent advances in this area are discussed.
Cationic, Two‐Coordinate Gold π Complexes
Authors: Brooner Rachel E. M. , Widenhoefer Ross A.
Published: October 2013

Cationic, two‐coordinate gold π complexes that contain a phosphine or N‐heterocyclic supporting ligand have attracted considerable attention recently owing to the potential relevance of these species as intermediates in the gold‐catalyzed functionalization of CC multiple bonds. Although neutral two‐coordinate gold π complexes have been known for over 40 years, examples of the cationic two‐coordinate gold(I) π complexes germane to catalysis remained undocumented prior to 2006. This situation has changed dramatically in recent years and well‐defined examples of two‐coordinate, cationic gold π complexes containing alkene, alkyne, diene, allene, and enol ether ligands have been documented. This Minireview highlights this recent work with a focus on the structure, bonding, and ligand exchange behavior of these complexes.
Transition‐Metal‐Catalyzed Laboratory‐Scale Carbon–Carbon Bond‐Forming Reactions of Ethylene
Authors: Saini Vaneet , Stokes Benjamin J. , Sigman Matthew S.
Published: October 2013

Ethylene, the simplest alkene, is the most abundantly synthesized organic molecule by volume. It is readily incorporated into transition‐metal‐catalyzed carbon–carbon bond‐forming reactions through migratory insertions into alkylmetal intermediates. Because of its D2h symmetry, only one insertion outcome is possible. This limits byproduct formation and greatly simplifies analysis. As described within this Minireview, many carbon–carbon bond‐forming reactions incorporate a molecule (or more) of ethylene at ambient pressure and temperature. In many cases, a useful substituted alkene is incorporated into the product.
A Theoretical Study on the Structure, Intramolecular Interactions, and Detonation Performance of Hydrazinium Dinitramide
Authors: Zhang Xueli , Liu Yan , Wang Fang , Gong Xuedong
Published: October 2013

The structures of hydrazinium dinitramide (HDN) in the gas phase and in aqueous solution have been studied at different levels of theory by using quantum chemistry. The intramolecular hydrogen‐bond interactions in HDN were studied by employing the quantum theory of atoms in molecules (QTAIM), as well as those in ammonium dinitramide (ADN), hydrazinium nitroformate (HNF), and ammonium nitroformate (ANF) for comparison. The results showed that HDN possessed the strongest hydrogen bonds, with the largest hydrogen‐bond energy (−47.95 kJ mol−1) and the largest total hydrogen‐bond energy (−60.29 kJ mol−1). In addition, the charge transfer between the cation and the anion, the binding energy, the energy difference between the frontier orbitals, and the second‐order perturbation energy of HDN were all the largest among the investigated compounds. These strongest intramolecular interactions accounted for the highest decomposition temperature of HDN among all four compounds. The IR spectra in the gas phase and in aqueous solution were very different and showed the significant influence of the solvent. The UV spectrum showed the strongest absorption at about 253 nm. An orbital‐interaction diagram demonstrated that the transition of electrons mainly happened inside the anion of HDN. The detonation velocity (D=8.34 km s−1) and detonation pressure (P=30.18 GPa) of HDN were both higher than those of ADN (D=7.55 km s−1 and P=24.83 GPa). The composite explosive HDN/CL‐20 with the weight ratio wCL−20/wHDN=0.388:0.612 showed the best performance (D=9.36 km s−1, P=39.82 GPa), which was close to that of CL‐20 (D=9.73 km s−1, P=45.19 GPa) and slightly better than that of the composite explosive ADN/CL‐20 (wCL−20/wADN=0.298:0.702, D=9.34 km s−1, P=39.63 GPa).
Biocatalytic Performance of pH‐Sensitive Magnetic Nanoparticles Derived from Layer‐by‐Layer Ionic Self‐Assembly of Chitosan with Glucoamylase
Authors: Wang Jian‐zhi , Zhao Guang‐hui , Li Yan‐feng , Peng Xiao‐meng , Li Yan‐tao
Published: October 2013

Based on the characteristics of polycations of chitosan and glucoamylase, which are oppositely charged, they were successfully alternatingly deposited onto the surface of aldehyde‐modified Fe3O4 nanoparticles by using a layer‐by‐layer ion exchange method to form magnetic carriers to construct multilayer films (designated as Fe3O4@(CS/GA)n). The (CS/GA)n film systems were endowed with the pH‐dependent properties of chitosan as well as the catalytic activity of glucoamylase. The changes in weight loss and surface chemistry, morphology, and magnetic sensitivity were monitored and verified by UV/Vis spectroscopy, zeta potential, TEM, and a vibrating sample magnetometer. Subsequently, the influence of the number of bilayers, storage stability, pH, temperature, and reusability of Fe3O4@(CS/GA)5 biocatalysts on catalytic activity were investigated. The results from characterization and determination remarkably indicate that Fe3O4@(CS/GA)5 presents excellent catalytic activity, storage stability, pH stability, and reusability in comparison with free enzyme. Fe3O4@(CS/GA)5 retained >60 % of its initial activity at 65 °C over 6 h; the optimum temperature and pH also increased to the ranges of 45–65 °C and 2.5–3.5, respectively, and only 27 % activity was lost after 10 cycles. This new strategy simplifies the reaction protocol and improves encapsulation efficiency and catalytic activity for new potential applications in biotechnology.