bluuebunny/crossref_metadata_2025 huggingface dataset:
Community health care workers’ risk perception of occupational exposure to HIV in Ibadan, south-west Nigeria
Authors: Akinboro Adamo A. , Adejumo Olabisi P. , Onibokun Comfort A. , Olowokere Eunice A.
Published: July 2012

Background: The ultimate goal of all healthcare workers (HCWs) is to maintain a healthy population and environment, and to adequately manage any condition that might constitute a menace to the health of the population at large. However, the central problem arising from the perception of risk of occupationally transmitted Human Immunodeficiency Virus (HIV) infection amongst HCWs is that it may distract them from giving quality healthcare. Objectives: The study aimed at addressing the following objectives: to explore the effects of level or years of experience on risk perception regarding occupational exposure to HIV, to assess HCWs’ daily work routines’ consistency in accordance with universal precaution guidelines, to determine HCWs’ perception of workplace safety climate and identify factors that may constitute constraints to HCWs in adhering to universal precaution measures.Method: A descriptive cross-sectional survey design was utilised, using a triangulation method of data collection which involved the use of a questionnaire and direct observational methods using checklists. A total of 143 HCWs were purposively selected to form the study population.Results: The study showed a very high risk-perception amongst HCWs regarding occupational exposure to HIV and AIDS but a poor compliance with universal precautions in their professional duties. HCWs perception of risk and workplace safety climate did not influence their compliance with universal precautions (Pr > F = 0.2566; Pr > F = 0.2776).Conclusion: The need for policy guidelines to manage all aspects of risk-perception and practices of HCWs regarding HIV and AIDS in the healthcare settings most especially at the primary health care level need to be considered.
Identification of Breast Cancer-Associated Lipids in Scalp Hair
Authors: Mistry Dharmica A.H. , Haklani Joseph , French Peter W.
Published: July 2012

A correlation between the presence of breast cancer and a change in the synchrotron-generated X-ray diffraction (XRD) pattern of hair has been reported in several publications by different groups, and on average XRD-based assays detect around 75% of breast cancer patients in blinded studies. To date, the molecular mechanisms leading to this alteration are largely unknown. We have determined that the alteration is likely to be due to the presence of one or more breast cancer-associated phospholipids. Further characterization of these lipids could be used to develop a novel, sensitive and specific screening test for breast cancer, based on hair initially, and potentially extendable to other biological samples.
Molecular Serum Markers of Liver Fibrosis
Authors: Liu Tianhui , Wang Xiaoming , Karsdal Morten A. , Leeming Diana J. , Genovese Federica
Published: July 2012

Fibrosis is a hallmark histologic event of chronic liver diseases and is characterized by the excessive accumulation and reorganization of the extracellular matrix (ECM). The gold standard for assessment of fibrosis is liver biopsy. As this procedure has various limitations, including risk of patient injury and sampling error, a non-invasive serum marker for liver fibrosis is desirable. The increasing understanding of the pathogenesis of hepatic fibrosis has suggested several markers which could be useful indicators of hepatic fibrogenesis and fibrosis. These markers include serum markers of liver function, ECM synthesis, fibrolytic processes, ECM degradation and fibrogenesis related cytokines. Recently, neo-epitopes, which are post-translational modifications of proteins, have been successfully used in bone and cartilage diseases which are characterized by extensive ECM remodeling. Increasing numbers of studies are being undertaken to identify neo-epitopes generated during liver fibrosis, and which ultimately might be useful for diagnosing and monitoring fibrogenesis. To date, the metalloproteinases generated fragment of collagen I, III, IV and VI have been proven to be elevated in two rat models of fibrosis. This review summarizes the recent efforts that have been made to identify potentially reliable non-invasive serum markers. We used the recently proposed BIPED (Burden of disease, Investigative, Prognostic, Efficacy and Diagnostic) system to characterize potential serum markers and neo-epitope markers that have been identified to date.
Identification and characterization of aging products in the glyoxal/ammonium sulfate system – implications for light-absorbing material in atmospheric aerosols
Authors: Kampf C. J. , Jakob R. , Hoffmann T.
Published: July 2012

Abstract. In this study we report the identification of bicyclic imidazoles in aqueous aerosol mimics using HPLC-ESI-MS/MS. 2,2'-Biimidazole was identified to be a major contributor to the 280 nm absorbance band observed in mixtures of glyoxal and ammonium sulfate, despite the fact that its production rate is two orders of magnitude lower than the previously reported production rates of imidazole or imidazole-2-carboxaldehyde. The molar absorptivity of 2,2'-biimidazole was determined to be (36 690 ± 998) M−1 cm−1. This demonstrates the necessity of molecular product identification at trace levels to enable a better understanding of relevant absorbing species. Additionally, the formation of lower polarity products including formamides of imidazoles is proposed. The role of imidazoles and other light-absorbing species in the formation of SOA and optical properties of SOA is discussed and potentially interesting fields for future investigations are outlined.
North Atlantic Oscillation and tropospheric ozone variability in Europe: model analysis and measurements intercomparison
Authors: Pausata F. S. R. , Pozzoli L. , Vignati E. , Dentener F. J.
Published: July 2012

Abstract. Ozone pollution represents a serious health and environmental problem. While ozone pollution is mostly produced by photochemistry in summer, elevated ozone concentrations can also be influenced by long range transport driven by the atmospheric circulation and stratospheric ozone intrusions. We analyze the role of large scale atmospheric circulation variability in the North Atlantic basin in determining surface ozone concentrations over Europe. Here, we show, using ground station measurements and a coupled atmosphere-chemistry model simulation for the period 1980–2005, that the North Atlantic Oscillation (NAO) does affect surface ozone concentrations – on a monthly timescale, over 10 ppbv in southwestern, central and northern Europe – during all seasons except fall. The commonly used NAO index is able to capture the link existing between atmospheric dynamics and surface ozone concentrations in winter and spring but it fails in summer. We find that the first Principal Component, computed from the time variation of the sea level pressure (SLP) field, detects the atmosphere circulation/ozone relationship not only in winter and spring but also during summer, when the atmospheric circulation weakens and regional photochemical processes peak. Given the NAO forecasting skill at intraseasonal time scale, the first Principal Component of the SLP field could be used as an indicator to identify areas more exposed to forthcoming ozone pollution events. Finally, our results suggest that the increasing baseline ozone in western and northern Europe during the 1990s could be related to the prevailing positive phase of the NAO in that period.
Dynamic recycling of gaseous elemental mercury in the boundary layer of the Antarctic Plateau
Authors: Dommergue A. , Barret M. , Courteaud J. , Cristofanelli P. , Ferrari C. P. , Gallée H.
Published: July 2012

Abstract. Gaseous elemental mercury (Hg(0)) was investigated in the troposphere and in the interstitial air extracted from the snow at Dome Concordia station (alt. 3320 m) on the Antarctic Plateau during January 2009. Measurements showed evidence of a very dynamic and daily cycling of Hg(0) inside the mixing layer with a range of values from 0.2 ng m−3 up to 2.3 ng m−3. During low solar irradiation periods, fast Hg(0) oxidation processes in a confined layer were observed leading to an enrichment of the upper snow layers in divalent Hg. Unexpectedly high Hg(0) concentrations for such a remote place were measured under higher solar irradiation due to the reemission of Hg(0) by the snowpack via photochemical reactions. Hg(0) concentrations showed a negative correlation with ozone mixing ratios, which contrasts with atmospheric mercury depletion events observed during the Arctic spring. It remains unclear whether halogens are involved in Hg(0) oxidation. We suggest that snow surfaces may play a role in promoting the heterogeneous oxidation of Hg(0). The cycling of other oxidants should be investigated together with Hg in order to clarify the complex reactivity on the Antarctic Plateau.
Field investigations of nitrogen dioxide (NO2) exchange between plants and the atmosphere
Authors: Breuninger C. , Meixner F. X. , Kesselmeier J.
Published: July 2012

Abstract. The nitrogen dioxide (NO2) exchange between the atmosphere and needles of Picea abies L. (Norway Spruce) was studied under uncontrolled field conditions using a dynamic chamber system. This system allows measurements of the flux density of the reactive NO-NO2-O3 triad and additionally of the non-reactive trace gases CO2 and H2O. For the NO2 detection a highly NO2 specific blue light converter was used, which was coupled to chemiluminescence detection of the photolysis product NO. This NO2 converter excludes known interferences with other nitrogen compounds, which occur by using more unspecific NO2 converters. Photo-chemical reactions of NO, NO2, and O3 inside the dynamic chamber were considered for the determination of NO2 flux densities, NO2 deposition velocities, as well as NO2 compensation point concentrations. The calculations based on a bi-variate weighted linear regression analysis (y- and x-errors considered). The NO2 deposition velocities for spruce, based on projected needle area, ranged between 0.07 and 0.42 mm s−1. The calculated NO2 compensation point concentrations ranged from 7.4 ± 6.40 to 29.0 ± 16.30 nmol m−3 (0.17–0.65 ppb) but the compensation point concentrations were all not significant in terms of compensation point concentration is unequal zero. These data challenge the existence of a NO2 compensation point concentration for spruce. Our study resulted in lower values of NO2 gas exchange flux densities, NO2 deposition velocities and NO2 compensation point concentrations in comparison to most previous studies. It is essential to use a more specific NO2 analyzer and to consider photo-chemical reactions between NO, NO2, and O3 inside the chamber.
Retrieval of tropospheric NO2 columns from SCIAMACHY combining measurements from limb and nadir geometries
Authors: Hilboll A. , Richter A. , Rozanov A. , Hodnebrog Ø. , Heckel A. , Solberg S. , Stordal F. , Burrows J. P.
Published: July 2012

Abstract. Satellite measurements of atmospheric trace gases have proved to be an invaluable tool for monitoring the Earth system. When these measurements are to be used for assessing tropospheric emissions and pollution, as for example in the case of nadir measurements of nitrogen dioxide (NO2), it is necessary to separate the stratospheric from the tropospheric signal. The SCIAMACHY instrument offers the unique opportunity to combine its measurements in limb and nadir viewing geometries into a tropospheric data product, using the limb measurements of the stratospheric NO2 abundances to correct the nadir measurements' total columns. In this manuscript, we present a novel approach to limb/nadir matching, calculating one stratospheric NO2 value from limb measurements for every single nadir measurement, abandoning global coverage for the sake of spatial accuracy. As a comparison, modelled stratospheric NO2 columns from the Oslo CTM2 are evaluated as stratospheric correction, and both datasets are confronted with the originally used reference sector method. Our study shows that stratospheric NO2 columns from SCIAMACHY limb measurements very well reflect stratospheric conditions. The zonal variability of stratospheric NO2 is captured by our matching algorithm, and the quality of the resulting tropospheric NO2 columns improves considerably. Modelled stratospheric NO2 columns from the Oslo CTM2 agree remarkably well with the measurements. Both datasets need to be matched to the level of the nadir measurements, however, because a time and latitude dependent bias between both stratospheric datasets and the measured nadir columns can be observed over clean regions. After accounting for this systematic bias between SCIAMACHY nadir observations and the stratospheric columns, both new stratospheric correction methods provide a significant improvement to the retrieval of tropospheric NO2 columns from the SCIAMACHY instrument.
Overlooked runaway feedback in the marine nitrogen cycle: the vicious cycle
Authors: Landolfi A. , Dietze H. , Koeve W. , Oschlies A.
Published: July 2012

Abstract. The marine nitrogen (N) inventory is controlled by the interplay of nitrogen loss processes, here referred to as denitrification, and nitrogen source processes, primarily nitrogen fixation. The apparent stability of the marine N inventory on time scales longer than the estimated N residence time, suggests some intimate balance between N sinks and sources. Such a balance may be perceived easier to achieve when N sinks and sources occur in close spatial proximity, and some studies have interpreted observational evidence for such a proximity as indication for a stabilizing feedback processes. Using a biogeochemical ocean circulation model, we here show instead that a close spatial association of N2 fixation and denitrification can, in fact, trigger destabilizing feedbacks on the N inventory and, because of stoichiometric constrains, lead to net N losses. Contrary to current notion, a balanced N inventory requires a regional separation of N sources and sinks. This can be brought about by factors that reduce the growth of diazotrophs, such as iron, or by factors that affect the fate of the fixed nitrogen remineralization, such as dissolved organic matter dynamics. In light of our findings we suggest that spatial arrangements of N sinks and sources have to be accounted for in addition to individual rate estimates for reconstructing past, evaluating present and predicting future marine N inventory imbalances.
Global ocean storage of anthropogenic carbon
Authors: Khatiwala S. , Tanhua T. , Mikaloff Fletcher S. , Gerber M. , Doney S. C. , Graven H. D. , Gruber N. , McKinley G. A. , Murata A. , Ríos A. F. , Sabine C. L. , Sarmiento J. L.
Published: July 2012

Abstract. The global ocean is a significant sink for anthropogenic carbon (Cant), absorbing roughly a third of human CO2 emitted over the industrial period. Robust estimates of the magnitude and variability of the storage and distribution of Cant in the ocean are therefore important for understanding the human impact on climate. In this synthesis we review observational and model-based estimates of the storage and transport of Cant in the ocean. We pay particular attention to the uncertainties and potential biases inherent in different inference schemes. On a global scale, three data based estimates of the distribution and inventory of Cant are now available. While the inventories are found to agree within their uncertainty, there are considerable differences in the spatial distribution. We also present a review of the progress made in the application of inverse and data-assimilation techniques which combine ocean interior estimates of Cant with numerical ocean circulation models. Such methods are especially useful for estimating the air-sea flux and interior transport of Cant, quantities that are otherwise difficult to observe directly. However, the results are found to be highly dependent on modeled circulation, with the spread due to different ocean models at least as large as that from the different observational methods used to estimate Cant. Our review also highlights the importance of repeat measurements of hydrographic and biogeochemical parameters to estimate the storage of Cant on decadal timescales in the presence of the variability in circulation that is neglected by other approaches. Data-based Cant estimates provide important constraints on ocean forward models, which exhibit both broad similarities and regional errors relative to the observational fields. A compilation of inventories of Cant gives us a "best" estimate of the global ocean inventory of anthropogenic carbon in 2010 of 155 Pg C with an uncertainty of ±20%. This estimate includes a broad range of values suggesting that a combination of approaches is necessary in order to achieve a robust quantification of the ocean sink of anthropogenic CO2.
Estimation of nitrogen budgets for contrasting catchments at the landscape scale
Authors: Vogt E. , Braban C. F. , Dragosits U. , Theobald M. R. , Billett M. F. , Dore A. J. , Tang Y. S. , van Dijk N. , Rees R. M. , McDonald C. , Murray S. , Skiba U. M. , Sutton M. A.
Published: July 2012

Abstract. A comprehensive assessment of nitrogen (N) flows at the landscape scale is fundamental to understand spatial interactions in the N cascade and to inform the development of locally optimised N management strategies. To explore this interactions, complete N budgets were estimated for two contrasting hydrological catchments (dominated by agricultural grassland vs. semi-natural peat-dominated moorland), forming part of an intensively studied landscape in southern Scotland. Local scale atmospheric dispersion modelling and detailed farm and field inventories provided high resolution estimations of input fluxes. Agricultural inputs (i.e. grazing excreta, organic and synthetic fertiliser) accounted for most of the catchment N inputs with 80% in the grassland and 57% in the moorland catchment, while atmospheric deposition made a significant contribution, particularly in the moorland catchment with 38% of the N inputs. The estimated catchment N budgets highlighted areas of key uncertainty, particularly N2 emissions from denitrification and stream N export. The resulting N balances suggest that the study catchments have a limited capacity to store N within soils, vegetation and groundwater. The "catchment N retention", i.e. the amount of N which is either stored within the catchment or lost through atmospheric emissions, was estimated to be 3% of the net anthropogenic input in the moorland and 55% in the grassland catchment. These values contrast with regional scale estimates: catchment retentions of net anthropogenic input estimated within Europe at the regional scale range from 50% to 90% with an average of 82% (Billen et al., 2011). This study emphasises the need for detailed budget analyses to identify the N status of European landscapes.
A simulation study of the ensemble-based data assimilation of satellite-borne lidar aerosol observations
Authors: Sekiyama T. T. , Tanaka T. Y. , Miyoshi T.
Published: July 2012

Abstract. A four-dimensional ensemble-based data assimilation system was assessed by observing system simulation experiments (OSSEs), in which the CALIPSO satellite was emulated via simulated satellite-borne lidar aerosol observations. Its performance over athree-month period was validated according to the Method for Object-based Diagnostic Evaluation (MODE), using aerosol optical thickness (AOT) distributions in East Asia as the objects of analysis. Consequently, this data assimilation system demonstrated the ability to produce better analyses of sulfate and dust aerosols in comparison to a free-running simulation model. For example, the mean centroid distance (from the truth) over a three-month collection period of aerosol plumes was improved from 2.15 grids (≈ 600 km) to 1.45 grids (≈ 400 km) for sulfate aerosols and from 2.59 grids (≈ 750 km) to 1.14 grids (≈ 330 km) for dust aerosols; the mean area ratio (to the truth) over a three-month collection period of aerosol plumes was improved from 0.49 to 0.76 for sulfate aerosols and from 0.51 to 0.72 for dust aerosols. The satellite-borne lidar data assimilation successfully improved the aerosol plume analysis and the dust emission estimation in the OSSEs. These results present great possibilities for the beneficial use of lidar data, whose distribution is vertically/temporally dense but horizontally sparse, when coupled with a four-dimensional data assimilation system. In addition, sensitivity tests were conducted, and their results indicated that the degree of freedom to control the aerosol variables was probably limited in the data assimilation because the meteorological field in the system was constrained to weather reanalysis using Newtonian relaxation. Further improvements to the aerosol analysis can be performed through the simultaneous assimilation of aerosol observations with meteorological observations. The OSSE results strongly suggest that the use of real CALIPSO data will have a beneficial effect on obtaining more accurate sulfate and dust aerosol analyses. Furthermore, the use of the same OSSE technique will allow us to perform a prior assessment of the next-generation lidar satellite EarthCARE, which will be launched in 2015.
Variational assimilation of streamflow into operational distributed hydrologic models: effect of spatiotemporal scale of adjustment
Authors: Lee H. , Seo D.-J. , Liu Y. , Koren V. , McKee P. , Corby R.
Published: July 2012

Abstract. State updating of distributed rainfall-runoff models via streamflow assimilation is subject to overfitting because large dimensionality of the state space of the model may render the assimilation problem seriously under-determined. To examine the issue in the context of operational hydrologic forecasting, we carried out a set of real-world experiments in which streamflow data is assimilated into the gridded Sacramento Soil Moisture Accounting (SAC-SMA) and kinematic-wave routing models of the US National Weather Service (NWS) Research Distributed Hydrologic Model (RDHM) via variational data assimilation (DA). The nine study basins include four in Oklahoma and five in Texas. To assess the sensitivity of the performance of DA to the dimensionality of the control vector, we used nine different spatiotemporal adjustment scales, with which the state variables are adjusted in a lumped, semi-distributed, or distributed fashion and biases in precipitation and PE are adjusted at hourly or 6-hourly scale, or at the scale of the fast response of the basin. For each adjustment scale, three different assimilation scenarios were carried out in which streamflow observations are assumed to be available at basin interior points only, at the basin outlet only, or at all locations. The results for the nine basins show that the optimum spatiotemporal adjustment scale varies from basin to basin and between streamflow analysis and prediction for all three streamflow assimilation scenarios. The most preferred adjustment scale for seven out of the nine basins is found to be distributed and hourly. It was found that basins with highly correlated flows between interior and outlet locations tend to be less sensitive to the adjustment scale and could benefit more from streamflow assimilation. In comparison with outlet flow assimilation, interior flow assimilation produced streamflow predictions whose spatial correlation structure is more consistent with that of observed flow for all adjustment scales. We also describe diagnosing the complexity of the assimilation problem using spatial correlation of streamflow and discuss the effect of timing errors in hydrograph simulation on the performance of the DA procedure.
Record extension for short-gauged water quality parameters using a newly proposed robust version of the Line of Organic Correlation technique
Authors: Khalil B. , Adamowski J.
Published: July 2012

Abstract. In many situations the extension of hydrological or water quality time series at short-gauged stations is required. Ordinary least squares regression (OLS) of any hydrological or water quality variable is a traditional and commonly used record extension technique. However, OLS tends to underestimate the variance in the extended records, which leads to underestimation of high percentiles and overestimation of low percentiles, given that the data are normally distributed. The development of the line of organic correlation (LOC) technique is aimed at correcting this bias. On the other hand, the Kendall-Theil robust line (KTRL) method has been proposed as an analogue of OLS with the advantage of being robust in the presence of outliers. Given that water quality data are characterised by the presence of outliers, positive skewness and non-normal distribution of data, a robust record extension technique is more appropriate. In this paper, four record-extension techniques are described, and their properties are explored. These techniques are OLS, LOC, KTRL and a new technique proposed in this paper, the robust line of organic correlation technique (RLOC). RLOC includes the advantage of the LOC in reducing the bias in estimating the variance, but at the same time it is also robust in the presence of outliers. A Monte Carlo study and empirical experiment were conducted to examine the four techniques for the accuracy and precision of the estimate of statistical moments and over the full range of percentiles. Results of the Monte Carlo study showed that the OLS and KTRL techniques have serious deficiencies as record-extension techniques, while the LOC and RLOC techniques are nearly similar. However, RLOC outperforms OLS, KTRL and LOC when using real water quality records.
Relating climate change signals and physiographic catchment properties to clustered hydrological response types
Authors: Köplin N. , Schädler B. , Viviroli D. , Weingartner R.
Published: July 2012

Abstract. We propose an approach to reduce a comprehensive set of 186 mesoscale catchments in Switzerland to fewer response types to climate change and to name sensitive regions as well as catchment characteristics that govern hydrological change. We classified the hydrological responses of our study catchments through an agglomerative-hierarchical cluster analysis, and we related the dominant explanatory variables, i.e. the determining catchment properties and climate change signals, to the catchments' hydrological responses by means of redundancy analysis. All clusters except for one exhibit clearly decreasing summer runoff and increasing winter runoff. This seasonal shift was observed for the near future period (2025–2046) but is particularly obvious in the far future period (2074–2095). Within a certain elevation range (between 1000 and 2500 m a.s.l.), the hydrological change is basically a function of elevation, because the latter governs the dominant hydro-climatological processes associated with temperature, e.g. the ratio of liquid to solid precipitation and snow melt processes. For catchments below the stated range, hydrological change is mainly a function of precipitation change, which is not as pronounced as the temperature signal is. Future impact studies in Switzerland can be conducted on a reduced sample of catchments representing the sensitive regions or covering a range of altitudes.
Impact of the sea surface temperature forcing on hindcasts of Madden-Julian Oscillation events using the ECMWF model
Authors: de Boisséson E. , Balmaseda M. A. , Vitart F. , Mogensen K.
Published: July 2012

Abstract. This paper explores the sensitivity of the prediction of Madden Julian Oscillation (MJO) events to different aspects of the sea surface temperature (SST) in the European Centre for Medium-range Weather Forecasts (ECMWF) model. The impact of temporal resolution of SST on the MJO is first evaluated via a set of monthly hindcast experiments. The experiments are conducted with an atmosphere forced by persisted SST anomalies, monthly and weekly SSTs. Skill scores are clearly degraded when weekly SSTs are replaced by monthly values or persisted anomalies. The new high resolution OSTIA SST daily reanalysis would in principle allow to establish the impact of daily versus weekly SST values on the MJO prediction. It is found however that OSTIA SSTs provide lower skill scores than the weekly product. Further experiments show that this loss of skill cannot be attributed to either the mean state or the daily frequency of OSTIA SSTs. Additional diagnostics show that the phase relationship between OSTIA SSTs and tropical convection is not optimal with repspect to observations. Such result suggests that capturing the correct SST-convection phase relationship is a major challenge for the MJO predictions.
Analysis of the snow-atmosphere energy balance during wet-snow instabilities and implications for avalanche prediction
Authors: Mitterer C. , Schweizer J.
Published: July 2012

Abstract. Wet-snow avalanches are notoriously difficult to predict, as their formation mechanism is poorly understood and in-situ measurements closely related to instability are inexistent. Instead, air temperature is commonly used as predictor variable for days with high wet-snow avalanche danger – with limited success. As melt water is a major driver of wet-snow instability and snow melt depends on the energy input into the snow cover, we computed the energy balance and study whether it is a better proxy than meteorological parameters such as air temperature for predicting periods with high wet-snow avalanche activity. The energy balance was partly measured and partly modelled for virtual slopes at different elevations for the aspects south and north using the 1-D snow cover model SNOWPACK. We used measured meteorological variables and computed energy balance and its components to compare wet-snow avalanche days to non-avalanche days for four consecutive winter seasons in the surroundings of Davos, Switzerland. Air temperature, the net shortwave radiation and the energy input integrated over 3 or 5 days showed best results in discriminating event from non-event days. Multivariate statistics, however, revealed that for better predicting avalanche days, information on the cold content of the snowpack is necessary. Wet-snow avalanche activity was closely related to periods when large parts of the snowpack reached an isothermal state (0 °C) and energy input exceeded a maximum value of 200 kJ m−2 in one day, or the 3-day sum of positive energy input was larger than 1.2 MJ m−2. Prediction accuracy with measured meteorological variables was as good as with computed energy balance parameters, but simulated energy balance variables accounted better for different aspects, slopes and elevations than meteorological data.
Technical Efficiency Measurement and Inverse 𝔹-Convexity: Moroccan Travel Agencies
Authors: Goncalves Olga , Liang Qi Bin , Peypoch Nicolas , Sbai Sara
Published: July 2012

This paper uses an innovative data envelopment analysis (DEA) model, the inverse 𝔹-convex model (Briec and Liang, 2011). This approach is used to measure the technical efficiency of Moroccan travel agencies. The travel agencies are ranked according to their efficiency over the period 2006–2008. The methodology is found to provide more accurate measurements of the travel agencies' efficiency. The paper also makes methodological and managerial contributions. Technical efficiency is analysed by using the inverse 𝔹-convexity model, comparing and contrasting it with traditional DEA methods. A key advantage of such an approach is that, on the one hand, traditional convexity assumption is relaxed and, on the other hand, it underlines potential complementarities of inputs. Finally, policy implications are derived.
Assessing the Impact of Shocks on International Tourism Demand for Portugal
Authors: Daniel Ana C.M. , Rodrigues Paulo M.M.
Published: July 2012

In this paper, a vector autoregressive (VAR) framework is used to model international tourism demand from the five main inbound tourism countries for Portugal: Germany, Spain, France, the Netherlands and the UK. Given the non-stationarity of the variables considered, vector error correction models (VECMs) are estimated. These are then used to analyse the impulse response functions in order to determine how international tourism demand for Portugal reacts to shocks to some of its important drivers, such as income, the cost of living in Portugal and the cost of living in Spain (the last as representative of the price in the main competing market with Portugal).
A Dynamic Analysis of Repeat Visitors
Authors: Moniz Ana Isabel
Published: July 2012

This paper introduces the dynamic probit model to analyse the underlying reasons behind repeat visits to the Azores Islands. The advantage of the model is that it allows investigation for lags as well as for endogeneity in the covariates, thus enabling a more accurate view of the repeat visits phenomenon in a specific tourism island destination. From the model estimation, it is clear that the number of visits to the Azores Islands is a time effect that should be analysed only with dynamic models which can identify persistent variables that attract repeat tourists. The repeat tourist is supported by multiple variables, such as overall satisfaction with the destination and specific satisfaction with destination attributes. However, the most important covariates are the destination attributes that are the persistent attractors of the repeat visitor. Related policy implications are derived.
Evaluating Operators' Attitudes to Educational Tourism in Dairy Farms: The Case of Japan
Authors: Ohe Yasuo
Published: July 2012

Although the educational function is attracting growing attention as a kind of multifunctionality in agriculture, educational services are not yet provided as a viable farm product. With regard to establishing a viable market for this service, this paper explores how the educational externality could be internalized by focusing on educational dairy farms in Japan. The author evaluates quantitatively the attitudes of operators towards establishing a viable service, as revealed by a questionnaire survey. First, a conceptual framework was devised to express their orientation towards an economically viable service by incorporating a stepwise internalization process of positive externalities with the help of a social learning network. Then, empirically, statistical tests were conducted and factors that determined this orientation, a viable service determinant function, were explored by means of the ordered logit model. The results show that, first, the higher the number of visitors to the farm the more operators are oriented towards a viable service, while no connection with ordinary dairy production is demonstrated. Second, social learning is effective for initiating the internalization process. Third, marketing skills become more important for upgrading the internalization level. Consequently, it is important to create opportunities for those farmers who want to provide consumers with educational services to learn a new role for agriculture and to establish a new income source.
Wine Tourism and Visitors' Perceptions: A Structural Equation Modelling Approach
Authors: Sampaio Ana
Published: July 2012

Wine tourism is emerging on an international level as a new product with significant economic potential and characteristics that may locate it in the paradigm of sustainable development. This paper analyses a specific wine tourism segment, Madeira wine tourism, in the global context of tourist consumer behaviour, through an examination of the perceptions of visitors to wineries. Specifically, the paper investigates the indirect influence of destination image construct on global tourist satisfaction, mediated by tourist wine involvement. A structural equation modelling (SEM) approach is used to develop and test conceptualized relationships between one exogenous and two endogenous constructs: tourist perceptions about the attractiveness of Madeira Island (destination image), tourist involvement in Madeira wine and global satisfaction constructs. The findings indicate that global tourist satisfaction is influenced directly by the tourists' level of wine involvement and indirectly by their image of Madeira Island. The policy implications of the results must be integrated into the international context of the wine tourism market segment in order to explore additional exchange profits from this economic activity, such as the impact of the country image and perceptions of the wine product on the promotion of wine tourism in Europe.
An Analysis of Visitors' Expenditures in a Tourist Destination: OLS, Quantile Regression and Instrumental Variable Estimators
Authors: Santos Carlos , Vieira José Cabral
Published: July 2012

The impact of tourism on the local economy and employment has been widely reported in the literature through the use of regional or county expenditure multipliers. Indeed, the money that visitors spend in a community is likely to be the benefit that residents probably recognize most readily. Despite this, only a few studies have focused on the determinants of tourist expenditure at the individual or household level. This paper sheds further light on this issue. For this purpose, the authors use information gathered by interviewing visitors about their levels of expenditure. The analysis focuses on total expenditure and expenditures on lodging, restaurants, shopping and car rental, and uses OLS, quantile regression and instrumental variable techniques. The results suggest that the impact of socio-demographic and trip-related characteristics on tourist expenditures goes far beyond the mean effect. Furthermore, correcting for the endogeneity of some explanatory variables might be a worthwhile exercise.
A General Equilibrium Analysis of Casino Taxation in Portugal
Authors: Schubert Stefan F. , Matias álvaro , Costa Carlos M.G.
Published: July 2012

In Portugal, casinos are taxed at a 50% rate and the tax receipts are allocated to Turismo de Portugal, which can use it in different ways – subsidizing tourism firms, advertising and so on. A recent study shows that casino demand in Portugal is originated predominantly in the domestic market. There is a debate about (i) the level of the tax levied on casinos and (ii) how the tax receipts should be used, as tourists rarely visit casinos. The paper contributes to this debate. The authors develop a dynamic general equilibrium model of a small open economy, comprising an industrial sector producing an internationally traded good, a tourism sector producing tourism services offered to both foreign tourists and residents and a casino sector supplying gambling services. Domestic residents derive utility from consuming the traded good, tourism services and gambling. The model is calibrated to the Portuguese economy. Using numerical simulations, the authors discuss the welfare effects of abandoning the taxation of casinos, as well as of different uses of casino tax receipts.
Activity of Naturally Derived Antimicrobial Peptides against Filamentous Fungi Relevant for Agriculture
Authors: Larrañaga Patricia , Díaz-Dellavalle Paola , Cabrera Andrea , Alem Diego , Leoni Carolina , Almeida-Souza André Luis , Giovanni-De-Simone Salvatore , Dalla-Rizza Marco
Published: July 2012

The search for environmentally biocompatible and cost-effective methods to control filamentous fungi in agriculture is becoming increasingly urgent. In vitro antimicrobial activity of three synthetic peptides was investigated against some filamentous fungi with agricultural relevance. The peptides were an analog of Temporin called Temporizina, a fragment from Pleurocidin termed Plc-2, and a peptide identified from sesame seeds named Pses3. Antimicrobial activity of these peptides towards filamentous fungi has not been previously reported. Seven plant pathogenic or mycotoxigenic fungal species, isolated from plant tissues were assayed: Alternaria solani, Colletotrichum gloesporioides, Fulvia fulvum, Fusarium oxisporum, Aspergillus niger, A. ochraceus and Penicillium digitatum. Values of Minimum Inhibitory Concentration (MIC) and Minimum Fungicidal Concentration (MFC) were determined and compared with the commercially available fungicide Captan as a positive control. The peptides showing greatest inhibition were Pses3 and Plc-2 and C. gloesporioides was the most sensitive of the evaluated fungi. The MIC values for Plc-2 and Pses3 peptides ranged from 0.64 µM to 10.25 µM. These values were much lower than those observed for Captan, suggesting the potential of these peptides as fungicides. In particular, Pses3 is a novel peptide derived from sesame seeds not reported in databases.
The Choices Facing Geriatrics
Authors: Patterson Christopher , Hogan David B. , Bergman Howard
Published: July 2012

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Translating Geriatric Psychiatry Research into Practice: Coping with Uncertainty
Authors: Rapoport Mark J.
Published: July 2012

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Abstracts from the 32nd Annual Scientific Meeting of the Canadian Geriatrics Society Quebec City, April 2012
Authors: Authors Various
Published: July 2012

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Letter From the Editor
Authors: Madden Ken
Published: July 2012

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Framing transparency: Crafting the utility bill to promote the real value of water
Authors: Goetz Melanie
Published: July 2012

By carefully crafting line item descriptors, utilities can use the monthly water bill as a means of educating customers.
Assessing options and costs versus benefits of a mobile work management solution
Authors: Dermody Chris , Ragsdale Phil
Published: July 2012

This first in a series of articles on a variety of real‐world utility experiences details how a metropolitan utility and its consultants worked together to arrive at an optimum work mobilization solution.
BAYWORK: The power of focused collaboration
Authors: Davis Cheryl , Curtis Catherine , Smith Jim , Weiss and Bert
Published: July 2012

Several San Francisco Bay Area water agencies realized that interagency cooperation would benefit them all; the result was BAYWORK, a sustainable collaboration model with applicability to the U.S. water utility community at large.
Strategic directions in the US water utility industry
Authors: Wallis‐Lage Cindy , Chevrette John
Published: July 2012

A survey of water utility leaders shows that financial issues, and all issues that drive investment or costs, remain front and center.
Moving From Adoption to Implementation of Numeric Nutrient Criteria
Authors: Flowers Wayne E. , Charles James E.
Published: July 2012

The overall purpose of the Clean Water Act (CWA) is “to restore and maintain the chemical, physical, and biological integrity of the Nation's Waters” (33 U.S.C. §1251(a) (1972)). This lofty goal is accomplished, in part, through setting water quality standards designed to protect designated uses for jurisdictional water bodies.
Key Properties of NiMnGa Based Single Crystals Grown with the SLARE Technique
Authors: Rolfs Katharina , Chmielus Markus , Guldbakke Jan M. , Wimpory Robert C. , Raatz Annika , Petry Winfried , Müllner Peter , Schneider Rainer
Published: July 2012

Magnetic shape memory alloys (MSMAs), exhibit large strains and hence are materials, which could substitute giant magnetostrictive and piezoelectrical materials in actuating devices. The actuation stress needed to induce the strain is much lower than in other actuator materials. Since the strain can be induced without phase transformation by a magnetic field, the development of actuators with high working frequencies is possible. However, for reasonable applications, large strains have to be induced with small magnetic fields. Up to now repeatable magnetically induced strains of 5–10% in magnetic fields of less than 500 mT have been achieved only in single crystals. The production of NiMnGa based single crystals is difficult and time consuming. The crystal quality is affected by porosity and impurities. With the Bridgeman based method called Slag Remelting and Encapsulation (SLARE) single crystalline ingots of NiMnGa, NiMnGaFe, and NiMnGaCo of high quality were grown and characterized. The results show that MSMA properties depend on the position within the single crystalline rods due to a composition gradient. The influence of surface treatment demonstrates that the decrease of surface roughness leads to a decrease of twinning stress. MSMAs with twinning stresses above 1 MPa show a magnetic field induced strain (MFIS) when tilting is not restricted by constraints. Softer samples can adapt to constraints much better and show large MFIS. Substituting Ni by Fe and Co, shifted the phase transitions successfully to higher temperatures. NiMnGa alloyed with up to 6 at.% Co showed three different martensite structures: a non‐modulated tetragonal structure, a modulated tetragonal structure, showing the same behavior as NiMnGa with identical structures and a non‐modulated orthorhombic structure with a stress–strain‐behavior explainable by the double twinning mechanism.
Photoelectric Effects in Single Domain BiFeO3 Crystals
Authors: Moubah Reda , Rousseau Olivier , Colson Dorothée , Artemenko Alla , Maglione Mario , Viret Michel
Published: July 2012

Energy harvesting from sunlight is essential in order to save fossil fuels, which are found in limited amount in the earth's crust. Photovoltaic devices converting light into electrical energy are presently made of semiconducting materials, but ferroelectrics are also natural candidates because of their internal built‐in electric field. Although they are clearly uncompetitive for mainstream applications, the possibility to output high photovoltages is making these materials reconsidered for targeted applications. However, their intrinsic properties regarding electronic transport and the origin of their internal field are poorly known. Here, it is demonstrated that under intense illumination and electric field, oxygen vacancies can be controllably generated in BiFeO3 to dramatically increase the conductance of BiFeO3 single crystals to a controllable value spanning 6 orders of magnitude while at the same time triggering light sensitivity in the form of photoconductivity, diode, and photovoltaic effects. Properties of the bulk and the Schottky interfaces with gold contacts are disentangled and it is shown that bulk effects are time dependent. The photocurrent has a direction that can be set by an applied field without changing the ferroelectric polarization direction. The self‐doping procedure is found to be essential in both the generation of electron hole pairs and the establishment of the internal field that separates them.
Building Bridges: Leveraging Interdisciplinary Collaborations in the Development of Biomaterials to Meet Clinical Needs
Authors: Fong Eliza L. S. , Watson Brendan M. , Kasper F. Kurtis , Mikos Antonios G.
Published: July 2012

Our laboratory at Rice University has forged numerous collaborations with clinicians and basic scientists over the years to advance the development of novel biomaterials and the modification of existing materials to meet clinical needs. This review highlights collaborative advances in biomaterials research from our laboratory in the areas of scaffold development, drug delivery, and gene therapy, especially as related to applications in bone and cartilage tissue engineering.