bluuebunny/crossref_metadata_2025 huggingface dataset:
Performance of Xpert® MTB/RIF among tuberculosis outpatients in Lilongwe, Malawi
Authors: Chikaonda Tarsizio , Nguluwe Nelson , Barnett Brian , Gokhale Runa H. , Krysiak Robert , Thengolose Isaac , Rosenberg Nora E. , Stanley Christopher , Mpunga James , Hoffman Irving F. , Hosseinipour Mina , Scott Lesley , Stevens Wendy
Published: April 2017

Background: Xpert® MTB/RIF is a molecular test for the detection of Mycobacterium tuberculosis and rifampicin resistance. It is considered to be a great advance over smear microscopy and culture. However, there is very little information regarding the performance characteristics of Xpert MTB/RIF in Malawi.Objective: We aimed to evaluate the performance of Xpert MTB/RIF in a Malawian setting.Methods: Stored sputum pellets were processed on Xpert MTB/RIF between June 2012 andMay 2014. Results were compared to mycobacteria growth indicator tube and Löwenstein-Jensen cultures, LED fluorescent microscopy and GenoType® MTBDRplus assay. Rifampicinresistance was confirmed by DNA sequencing.Results: Of the 348 specimens with valid Xpert MTB/RIF results, 129/348 (37%) were smearpositive and 198/348 (57%) were culture-positive. Xpert MTB/RIF demonstrated a sensitivity of 93.8% (95% CI 89.4% – 96.8%) and specificity of 97.4% (95% CI 93.5% – 99.3%), with a positive predictive value of 97.8% (95% CI 94.6% – 99.4%) and a negative predictive value of 92.6% (95% CI 87.4% – 96.1%). Xpert MTB/RIF correctly identified 185/186 (99.5%) rifampicin sensitive and 2/2 (100%) rifampicin-resistant M. tuberculosis strains. Mutations were notdetected by sequencing in one isolate which was rifampicin resistant on Xpert MTB/RIF butsensitive on MTBDRplus. Four non-tuberculous mycobacteria grew from four smear-negativespecimens, namely, M. avium (n = 1) and M. intracellulare (n = 3). No cross-reactivity wasobserved with any of the non-tuberculous mycobacteria when using Xpert MTB/RIF.Conclusion: When fully implemented, Xpert MTB/RIF may have an impact on patient care inMalawi. The increased diagnostic yield of Xpert MTB/RIF over smear microscopy can increaselaboratory-confirmed tuberculosis detection and ensure that treatment is given to appropriateindividuals or groups.
Tuberculosis diagnostic networks: Moving beyond the laboratory to end tuberculosis in Africa
Authors: Piatek Amy
Published: April 2017

No abstract available.
Diversity, variation and fairness: Equivalence in national level language assessments
Authors: Weideman Albert , Du Plessis Colleen , Steyn Sanet
Published: April 2017

The post-1994 South African constitution proudly affirms the language diversity of the country, as do subsequent laws, while ministerial policies, both at further and higher education level, similarly promote the use of all 11 official languages in education. However, such recognition of diversity presents several challenges to accommodate potential variation. In language education at secondary school, which is nationally assessed, the variety being promoted immediately raises issues of fairness and equivalence. The final high-stakes examination of learners’ ability in home language at the exit level of their pre-tertiary education is currently contentious in South Africa. It is known, for example, that in certain indigenous languages, the exit level assessments barely discriminate among learners with different abilities, while in other languages they do. For that reason, the Council for Quality Assurance in General and Further Education, Umalusi, has commissioned several reports to attempt to understand the nature of the problem. This article will deal with a discussion of a fourth attempt by Umalusi to solve the problem. That attempt, undertaken by a consortium of four universities, has already delivered six interim reports to this statutory body, and the article will consider some of their content and methodology. In their reconceptualisation of the problem, the applied linguists involved first sought to identify the theoretical roots of the current curriculum in order to articulate more sharply the construct being assessed. That provides the basis for a theoretical justification of the several solutions being proposed, as well as for the preliminary designs of modifications to current, and the introduction of new assessments. The impact of equivalence of measurement as a design requirement will be specifically discussed, with reference to the empirical analyses of results of a number of pilots of equivalent tests in different languages.
Strategies for building wordnets for under-resourced languages: The case of African languages
Authors: Bosch Sonja E. , Griesel Marissa
Published: April 2017

The African Wordnet Project (AWN) aims at building wordnets for five African languages: Setswana, isiXhosa, isiZulu, Sesotho sa Leboa (also referred to as Sepedi or Northern Sotho) and Tshivenda. Currently, the so-called expand model, based on the structure of the English Princeton WordNet (PWN), is used to continually develop the African Wordnets manually. This is a labour-intensive work that needs to be performed by linguistic experts, guided by several considerations such as the level of lexicalisation of a term in the African language. Up to now, linguists were responsible for identifying and translating appropriate synsets without much help from electronic resources because in the case of African languages even basic resources such as computer readable and electronic bilingual wordlists are usually not freely available. Methods to speed up the manual development of synsets and ease the workload of the human language experts were recently investigated. These centred around utilising the minimal amount of information available in bilingual dictionaries to identify synsets in the PWN that should be included in the AWN, transferring information from dictionaries to the wordnet and presenting the potential synsets to linguists for final approval and inclusion in the wordnets. In this article, we describe the methodology developed for building the African Wordnets, a potentially significant resource for natural language processing applications. Available resources that could be taken advantage of and resources that had to be developed are investigated, and initial results and future plans are explained.
Syferfontein, ’n plaastragedie van selfsug en woede aanmekaargesit
Authors: Van Heerden Neil
Published: April 2017

No abstract available.
Maternal complication prevention: evidence from a case-control study in southwest Nigeria
Authors: Osungbade Kayode O. , Ayinde Olubunmi O.
Published: April 2017

Background: The importance of strengthening maternal health services as a preventive intervention for morbidities and complications during pregnancy and delivery in developing countries cannot be over-emphasised, since use of prenatal health services improves maternal health outcomes.Aim: This study investigated differences in risk factors for maternal complications in booked and unbooked pregnant women in Nigeria, and provided evidence for their prevention.Setting: The study was carried out in a postnatal ward in a secondary health facility.Methods: This was a case-control study involving booked and unbooked pregnant women who had delivered. Consecutive enrolment of all unbooked pregnant women (cases) was done, and one booked pregnant woman (control) was enrolled and matched for age with each of these. Both groups were interviewed using a questionnaire, whilst records of delivery were extracted from the hospital files. Findings were subjected to logistical regression at a significance level of p < 0.05.Results: Booked women had a lower median length of labour (10 hours) compared to unbooked women (13 hours). More women in the booked control group (139; 35.1%) than in the unbooked case group (96; 23.6%) reported at least one type of morbidity during the index pregnancy (p = 0.0004). Booking status was associated with a likelihood of spontaneous vaginal delivery. Young maternal age, low education, rural residence and low socio-economic status were associated with less likelihood of using prenatal services. Young maternal age, low education and intervention in the delivery were associated with a likelihood of experiencing a complication of delivery.Conclusion: Strengthening antenatal and secondary healthcare services as short- and mediumterm measures might be cost-effective as a preventive strategy in complications of pregnancy,whilst socio-economic dimensions of health are accorded priority in the long term.
Assembly of a conduct risk regulatory model for developing market banks
Authors: Hargarter Antje , Van Vuuren Gary
Published: April 2017

Background: The substantial penalties imposed on banks in the recent past for various conduct irregularities have given rise to a new type of risk called conduct risk. Conduct risk comes about when financial services companies conduct themselves in an inappropriate way towards their customers, resulting in a negative (economic) outcome for the customer. What makes the management and mitigation of conduct risk by banks so different is that it cannot be easily integrated into a bank’s standard risk management framework. So far, the concept of conduct risk has not been formally covered by the Basel Accords.Aim: There are, however, global efforts by international organisations and local regulators to control it – with little clarity on the ‘how’. The aim of this study is to explore this ‘how’.Setting: While regulators need to protect customers, resulting in a positive outcome for the customer, they must also ensure that banks take conduct risk management and its mitigation seriously. At the same time, any regulatory model for conduct risk needs to be incorporated into the existing bank regulatory strategy and methodology and assimilated with the profile of a country.Methods: An exploratory model that regulators could use to keep conduct risk at bay is developed based on primary and secondary data and this is then applied to the South African, Kenyan and Malaysian milieus to determine what can be learnt about conduct risk in emerging economies.Results: The model investigates the interrelationships between different goals that regulators ideally need to achieve and the findings show that regulators have a difficult task balancing these goals and at the same time achieving a positive outcome.Conclusion: Based on the model, the recommendation for regulators in the developing world would be to collaborate in their approach to conduct risk, as they might face similar difficulties and operate in a comparable context.
A comparison of the value relevance of interim and annual financial statements
Authors: Zulu Mbalenhle , De Klerk Marna , Oberholster Johan G.I.
Published: April 2017

Background: This study tests the value relevance of interim accounting information. The study also explores whether the value relevance of annual and interim financial statements has changed over time.Aim: It explores whether the value relevance of interim financial statements is higher than the value relevance of annual financial statements. Finally, it investigates whether accounting information published in interim and annual financial statements has incremental value relevance.Setting: Data for the period from 1999 to 2012 were collected from a sample of non-financial companies listed on the Johannesburg Stock Exchange.Method: The Ohlson model to investigate the value relevance of accounting information was used for the study.Results: The results show that interim book value of equity is value relevant while interim earnings are not. Interim financial statements appear to have higher value relevance than annual financial statements. The value relevance of interim and annual accounting information has remained fairly constant over the sample period. Incremental comparisons provide evidence that additional book value of equity and earnings that accrue to a company between interim and annual reporting dates are value relevant.Conclusion: The study was conducted over a long sample period (1999–2012), in an era when a technology-driven economy and more timely reporting media could have had an effect on the value relevance of published accounting information. To the best of our knowledge, this is the first study to evaluate and compare the value relevance of published interim and annual financial statements.
Fractional Black–Scholes option pricing, volatility calibration and implied Hurst exponents in South African context
Authors: Flint Emlyn , Maré Eben
Published: April 2017

Background: Contingent claims on underlying assets are typically priced under a framework that assumes, inter alia, that the log returns of the underlying asset are normally distributed. However, many researchers have shown that this assumption is violated in practice. Such violations include the statistical properties of heavy tails, volatility clustering, leptokurtosis and long memory. This paper considers the pricing of contingent claims when the underlying is assumed to display long memory, an issue that has heretofore not received much attention.Aim: We address several theoretical and practical issues in option pricing and implied volatility calibration in a fractional Black–Scholes market. We introduce a novel eight-parameter fractional Black–Scholes-inspired (FBSI) model for the implied volatility surface, and consider in depth the issue of calibration. One of the main benefits of such a model is that it allows one to decompose implied volatility into an independent long-memory component – captured by an implied Hurst exponent – and a conditional implied volatility component. Such a decomposition has useful applications in the areas of derivatives trading, risk management, delta hedging and dynamic asset allocation.Setting: The proposed FBSI volatility model is calibrated to South African equity index options data as well as South African Rand/American Dollar currency options data. However, given the focus on the theoretical development of the model, the results in this paper are applicable across all financial markets.Methods: The FBSI model essentially combines a deterministic function form of the 1-year implied volatility skew with a separate deterministic function for the implied Hurst exponent, thus allowing one to model both observed implied volatility surfaces as well as decompose them into independent volatility and long-memory components respectively. Calibration of the model makes use of a quasi-explicit weighted least-squares optimisation routine.Results: It is shown that a fractional Black–Scholes model always admits a non-constant implied volatility term structure when the Hurst exponent is not 0.5, and that 1-year implied volatility is independent of the Hurst exponent and equivalent to fractional volatility. Furthermore, we show that the FBSI model fits the equity index implied volatility data very well but that a more flexible Hurst exponent parameterisation is required to fit accurately the currency implied volatility data.Conclusion: The FBSI model is an arbitrage-free deterministic volatility model that can accurately model equity index implied volatility. It also provides one with an estimate of the implied Hurst exponent, which could be very useful in derivatives trading and delta hedging.
Patients’ recommendations for a patient-centred public antiretroviral therapy programme in eThekwini, KwaZulu-Natal
Authors: Mulqueeny Delarise M. , Taylor Myra
Published: April 2017

Background: The South African antiretroviral therapy (ART) programme, which is in its second decade of existence, includes many successes and challenges. This study provides patients’ recommendations to address the challenges they currently experience at four antiretroviral (ARV) clinics based in urban public hospitals in order to provide a patient-centred service.Objectives: To use patients’ recommendations to develop intervention strategies to improve patients’ experiences of the public ART programme.Method: A three-stage, sequential, mixed-method study was implemented. Stage 1 recruited five patients from the four sites to formulate and test a structured questionnaire prior to data collection. Stage 2 recruited a stratified random sample of 400 patients (100 from each hospital) to complete the administered structured questionnaire. Stage 3 purposively selected 12 patients (three from each of the four sites) to participate in in-depth audio-recorded interviews using an interview schedule.Results: The 412 patients prioritised six recommendations, which are as follows: waiting areas should be enclosed to protect patients from the elements (rain, sun, lightening, wind and cold); patients should not have to return their files to the main hospital or ARV clinic themselves; stable patients should collect their ARV drugs every three months; pharmacy opening and closing times should be revised to suit patients’ needs; HIV-positive patient representatives should be elected at each ARV clinic to address patients’ concerns and/or challenges to ensure that the programme could be more patient-centred and ARV clinic operating times should be extended to open later during weekdays and over weekends.Conclusion: Patients living with HIV have a valuable contribution to make in assessing service delivery and making recommendations to create a patient-centred healthcare environment, which will feasibly increase their adherence to ART.
Delays in switching patients onto second-line antiretroviral treatment at a public hospital in eThekwini, KwaZulu-Natal
Authors: Narainsamy Denver , Mahomed Saajida
Published: April 2017

Background: South Africa has one of the largest antiretroviral treatment (ART) programmes globally. In addition to increasing access to ART, it is important that the health system also focuses on the appropriate management of patients who fail first-line ART. Delays in switching patients onto second-line ART can adversely affect patient outcomes.Aim: To identify the patient-related and programmatic factors that delay switching patients onto second-line ART, and to assess whether these delays contribute to subsequent virological failure.Methods: Clinical records of adult patients switched onto second-line ART between 2011 and 2014 at a public antiretroviral clinic were used to collect demographic, clinical, laboratory and programmatic data (availability of viral load results, inadequate patient follow-up, insufficient notes for effective follow-up). Data were analysed using univariate and multivariate logistic regression.Results: The median duration from the date of first and confirmatory documented high viral load (VL > 1000 copies/mL) to being switched to second-line ART was 13.2 months [interquartile range (IQR) 1.1–52.7 months] and 6.4 months (IQR 0–43.3 months), respectively. Inadequate prescriber notes for appropriate follow-up (p = 0.01) and unavailability of patients’ viral load results (p = 0.02) were significantly associated with delays in switching to second-line ART. There was no significant association between the time taken to switch to second-line ART and subsequent virological failure.Conclusion: We observed lengthy delays in switching patients to second-line ART. Modifiable programmatic factors were found to be significantly associated with delays in switching to second-line ART.
Factors affecting direct and indirect benefit exchange in the social media–based learning experience
Authors: Mkhize Peter L. , Nxumalo Lindelani S.
Published: April 2017

Background: Social media platforms are thriving on the co-creation of content, usually socially orientated content about the social interests of participants. There is also a growing trend of social media application in the human resources and marketing for business purposes. This study investigates factors that have an impact on the sharing of knowledge on social media platforms, particularly students at an Open Distance Learning (ODL) institution.Objective: This study evaluates the difference between direct and indirect benefit exchange expected by students when sharing knowledge.Method: Random and theoretical sampling were used to select the sample in this study from the population. A literature-informed questionnaire was used as an instrument to collect data from a selected sample of 315 students from the School of Computing at the University of South Africa.Results: A test of association was conducted to evaluate correlations, which revealed that only reputation and social language correlate with direct and indirect benefit exchange. Results indicate that there is a significant mean difference between direct and indirect benefit exchange and that issues concerning social identity and trust should be taken into account when developing social media instructional design.Conclusion: In this study, a survey was used to test the hypothesis. The authors concluded that instructional designer can design teaching and learning experience in the social media platform by catering for both direct and indirect benefit knowledge exchange. The results of the study further confirmed that some students share knowledge with the expectation of direct exchange benefit and, meanwhile, expect indirect exchange benefit.
The development of an evidence-based clinical checklist for the diagnosis of anterior knee pain
Authors: Leibbrandt Dominique C. , Louw Quinette
Published: April 2017

Background: Anterior knee pain (AKP) or patellofemoral pain syndrome is common and may limit an individual’s ability to perform common activities of daily living such as stair climbing and prolonged sitting. The diagnosis is difficult as there are multiple definitions for this disorder and there are no accepted criteria for diagnosis. It is therefore most commonly a diagnosis that is made once other pathologies have been excluded. Objectives: The aim of this study was to create an evidence-based checklist for researchers and clinicians to use for the diagnosis of AKP. Methods: A systematic review was conducted in July 2016, and an evidence-based checklist was created based on the subjective and objective findings most commonly used to diagnose AKP. For the subjective factors, two or more of the systematic reviews needed to identify the factor as being important in the diagnosis of AKP. Results: Two systematic reviews, consisting of nine different diagnostic studies, were identified by our search methods. Diagnosis of AKP is based on the area of pain, age, duration of symptoms, common aggravating factors, manual palpation and exclusion of other pathologies. Of the functional tests, squatting demonstrated the highest sensitivity. Other useful tests include pain during stair climbing and prolonged sitting. The cluster of two out of three positive tests for squatting, isometric quadriceps contraction and palpation of the patella borders and the patella tilt test were also recommended as useful tests to include in the clinical assessment. Conclusion: A diagnostic checklist is useful as it provides a structured method for diagnosing AKP in a clinical setting. Research is needed to establish the causes of AKP as it is difficult to diagnose a condition with unknown aetiology.
An analysis of diagnostic practices in a mammography unit in a tertiary hospital in South Africa
Authors: Surridge Clare A. , Goodier Matthew D.M.
Published: April 2017

Background: Breast cancer is the most common cancer in females in South Africa. The reporting of breast imaging has been standardised internationally using the Breast Imaging and Reporting Data System (BI-RADS), which includes guidelines for reporting of breast lesions and further management. Ultrasound-guided core-needle breast (UGCNB) biopsy is a widely used method of obtaining histological diagnoses of breast lesions to assist with planning definitive management.Objectives: To perform an audit of the UGCNB biopsies performed at the Grey’s Hospital Mammography Department and assess the accuracy of the radiologists’ use of the BI-RADS scoring system.Methods: Records of all patients who underwent UGCNB biopsy between 01 January 2014 and 31 October 2015 were reviewed. A retrospective study was performed.Results: A total of 304 UGCNB biopsies were performed on 291 patients. The mean age was 49.2 (s.d. = 15.9) years. Tissue samples from 303 lesions were adequate for histological assessment, and of these, 51% of the lesions were malignant whilst 49% were benign. The most common malignant and benign diagnoses were invasive ductal carcinoma and fibroadenoma respectively. The BI-RADS scoring of the radiologists demonstrated a positive predictive value of 61.6% for the identification of possible malignant lesions.Conclusion: This study describes the patient and lesion profile and unit practices in a tertiary hospital setting in South Africa. The radiologists’ application of the BI-RADS scoring largely conforms to the BI-RADS guidelines. The study highlights several challenges encountered by a breast imaging programme in an under-resourced setting as well as making recommendations in overcoming these challenges.
An assessment of the accuracy of contrast enema for the diagnosis of Hirschsprung disease at a South African tertiary hospital
Authors: Msomi Monica S. , Mangray Hansraj , Du Plessis Vicci
Published: April 2017

Objectives: To compare radiological findings with the histological diagnosis of Hirschsprung disease (HD) to establish the usefulness of contrast enema as an initial screening and diagnostic tool. To correlate accuracy of radiological diagnosis at Grey’s Hospital with international standards.Materials and methods: Systematic searches were conducted through the Picture Archiving and Communication System and the National Health Laboratory Service records for patients aged 0–12 years, with clinically suspected HD, for whom both contrast enemas and rectal biopsies were performed between 01 January 2011 and 31 August 2015 in a tertiary-level hospital. A total of 54 such patients were identified. Diagnostic accuracy levels were calculated by comparing radiological results with histology results, which is the gold standard.Results: Diagnostic accuracy of contrast enema was 78%, sensitivity was 94.4% and the negative predictive value was 95.7%. Specificity (68.8%) and positive predictive values (63%) were considerably lower. A lower false-negative rate of 5.6% was obtained at Grey’s Hospital as compared with the international reports of up to 30%.Conclusion: Contrast enema remains useful as an initial screening and diagnostic test for HD. Results of this South African tertiary referral hospital were consistent with the best international results for sensitivity of the contrast enema (approximately 80% – 88% in excluding the disease).
Narrative Concepts in the Study of Eighteenth-Century Literature
Authors: Steinby Liisa , Mäkikalli Aino , McKeon Michal , Richetti John , Fludernik Monika , Kukkonen Karin , Nitschke Claudia , Birke Dorothee , Prithchard Penny , Rogers Pat , Ikonen Teemu , Waldschmidt Christine
Published: April 2017

This collection of essays studies the encounter between allegedly ahistorical concepts of narrative and eighteenth-century literature from across Europe. At issue is the question of whether the theoretical concepts underpinning narratology are, despite their appearance of ahistorical generality, actually derived from the historical study of a particular period and type of literature. The essays take on aspects of eighteenth-century texts such as plot, genre, character, perspective, temporality, and more, coming at them from both a narratological and a historical perspective.
Rainfall drives atmospheric ice nucleating particles in the maritime
climate of Southern Norway
Authors: Conen Franz , Eckhardt Sabine , Gundersen Hans , Stohl Andreas , Yttri Karl Espen
Published: April 2017

Abstract. Ice nucleating particles active at warm temperatures (e.g. −8 °C; INP−8) can transform clouds from liquid to mixed-phase, even at very small number concentrations (
Effects of NOx and SO2 on the Secondary Organic Aerosol Formation from Photooxidation of α-pinene and Limonene
Authors: Zhao Defeng , Schmitt Sebastian H. , Wang Mingjin , Acir Ismail-Hakki , Tillmann Ralf , Tan Zhaofeng , Novelli Anna , Fuchs Hendrik , Pullinen Iida , Wegener Robert , Rohrer Franz , Wildt Jürgen , Kiendler-Scharr Astrid , Wahner Andreas , Mentel Thomas F.
Published: April 2017

Abstract. Anthropogenic emissions such as NOx and SO2 influence the biogenic secondary organic aerosol (SOA) formation, but detailed mechanisms and effects are still elusive. We studied the effects of NOx and SO2 on the SOA formation from photooxidation of α-pinene and limonene at ambient relevant NOx and SO2 concentrations (NOx:
Classifying aerosol type using in situ surface spectral aerosol
optical properties
Authors: Schmeisser Lauren , Andrews Elisabeth , Ogren John A. , Sheridan Patrick , Jefferson Anne , Sharma Sangeeta , Kim Jeong Eun , Sherman James P. , Sorribas Mar , Kalapov Ivo , Arsov Todor , Angelov Christo , Mayol-Bracero Olga L. , Labuschagne Casper , Kim Sang-Woo , Hoffer András , Lin Neng-Heui , Chia Hao-Ping , Bergin Michael , Sun Junying , Liu Peng , Wu Hao
Published: April 2017

Abstract. Knowledge of aerosol size and composition is important for determining radiative forcing effects of aerosols, identifying aerosol sources, and improving aerosol satellite retrieval algorithms. The ability to extrapolate aerosol size and composition, or type, from intensive aerosol optical properties can help expand the current knowledge of spatio-temporal variability of aerosol type globally, particularly where chemical composition measurements do not exist concurrently with optical property measurements. This study uses medians of scattering Ångström exponent (SAE), absorption Ångström exponent (AAE) and single scattering albedo (SSA) from 24 stations within the NOAA federated aerosol network to infer aerosol type using previously published aerosol classification schemes. Three methods are implemented to obtain a best estimate of dominant aerosol type at each station using aerosol optical properties. The first method plots station medians into an AAE vs. SAE plot space, so that a unique combination of intensive properties corresponds with an aerosol type. The second typing method expands on the first by introducing a multivariate cluster analysis, which aims to group stations with similar optical characteristics, and thus similar dominant aerosol type. The third and final classification method pairs 3-day backward air mass trajectories with median aerosol optical properties to explore the relationship between trajectory origin (proxy for likely aerosol type) and aerosol intensive parameters, while allowing for multiple dominant aerosol types at each station. The three aerosol classification methods have some common, and thus robust, results. In general, estimating dominant aerosol type using optical properties is best suited for site locations with a stable and homogenous aerosol population, particularly continental polluted (carbonaceous aerosol), marine polluted (carbonaceous aerosol mixed with sea salt), and continental dust/biomass sites (dust and carbonaceous aerosol); however, current classification schemes perform poorly when predicting dominant aerosol type at remote marine and Arctic sites, and at stations with more complex locations and topography where variable aerosol populations are not well represented by median optical properties. Although the aerosol classification methods presented here provide new ways to reduce ambiguity in typing schemes, there is more work needed to find aerosol typing methods that are useful for a larger range of geographic locations and aerosol populations.
FATES: a flexible analysis toolkit for the exploration of single-particle mass spectrometer data
Authors: Sultana Camille M. , Cornwell Gavin C. , Rodriguez Paul , Prather Kimberly A.
Published: April 2017

Abstract. Single-particle mass spectrometer (SPMS) analysis of aerosols has become increasingly popular since its invention in the 1990s. Today many iterations of commercial and lab-built SPMSs are in use worldwide. However, supporting analysis toolkits for these powerful instruments are outdated, have limited functionality, or are versions that are not available to the scientific community at large. In an effort to advance this field and allow better communication and collaboration between scientists, we have developed FATES (Flexible Analysis Toolkit for the Exploration of SPMS data), a MATLAB toolkit easily extensible to an array of SPMS designs and data formats. FATES was developed to minimize the computational demands of working with large data sets while still allowing easy maintenance, modification, and utilization by novice programmers. FATES permits scientists to explore, without constraint, complex SPMS data with simple scripts in a language popular for scientific numerical analysis. In addition FATES contains an array of data visualization graphic user interfaces (GUIs) which can aid both novice and expert users in calibration of raw data; exploration of the dependence of mass spectral characteristics on size, time, and peak intensity; and investigations of clustered data sets.
Practical field calibration of electrochemical NO2
sensors for urban air quality applications
Authors: Mijling Bas , Jiang Qijun , de Jonge Dave , Bocconi Stefano
Published: April 2017

Abstract. In many urban areas the population is exposed to elevated levels of air pollution. However, air quality is usually only measured at a few locations. These measurements provide a general picture of the state of the air, but they are unable to monitor local differences. Since a few years new low-cost sensor technology is available, which has the potential to extend the official monitoring network significantly. These sensors, however, are still in an experimental stage and suffer from various technical issues which limit their applicability. This study explores the added value of alternative air quality measurements, focusing on nitrogen dioxide (NO2) in Amsterdam, the Netherlands. 16 low-cost air quality sensor devices were built and distributed among volunteers living close to roads with high traffic volume for a two-month measurement campaign. Careful calibration of individual sensors is essential to measure ambient concentrations of NO2 significantly. Field calibration was done next to an air monitoring station during an 8-day period, resulting in R2 ranging from 0.3 to 0.7. The NO2 accuracy can be improved by including temperature and humidity measurements from an additional low-cost sensor, R2 ranging from 0.6 to 0.9. Recalibration is crucial, as all sensors show significant signal drift after the two-month measurement campaign. The measurement series between the calibration periods can be corrected in hindsight by taking a weighted average of the calibration coefficients. Validation against an independent air monitoring station shows good agreement. Using our approach, the standard deviation of a typical sensor device for NO2 measurements was found to be 7 μg m−3. This shows that, if properly treated, low-cost sensors based on the current generations of electrochemical NO2 sensors may provide useful complementary data on local air quality in an urban setting.
Temporal changes in photoreactivity of dissolved organic carbon and implications for aquatic carbon fluxes from peatlands
Authors: Pickard Amy E. , Heal Kate V. , McLeod Andrew R. , Dinsmore Kerry J.
Published: April 2017

Abstract. Aquatic systems draining peatland catchments receive a high loading of dissolved organic carbon (DOC) from the surrounding terrestrial environment. Whilst photo-processing is known to be an important process in the transformation of aquatic DOC, the drivers of temporal variability in this pathway are less well understood. In this study, 8 h laboratory irradiation experiments were conducted on water samples collected from two contrasting peatland aquatic systems in Scotland: a peatland stream and a reservoir in a catchment with high percentage peat cover. Samples were collected monthly at both sites from May 2014 to May 2015 and from the stream system during two rainfall events. DOC concentrations, absorbance properties and fluorescence characteristics were measured to investigate characteristics of the photochemically labile fraction of DOC. CO2 and CO produced by irradiation were also measured to determine gaseous photoproduction and intrinsic sample photoreactivity. Significant variation was seen in the photoreactivity of DOC between the two systems, with total irradiation-induced changes typically 2 orders of magnitude greater at the high-DOC stream site. This is attributed to longer water residence times in the reservoir rendering a higher proportion of the DOC recalcitrant to photo-processing. During the experimental irradiation, 7 % of DOC in the stream water samples was photochemically reactive and direct conversion to CO2 accounted for 46 % of the measured DOC loss. Rainfall events were identified as important in replenishing photoreactive material in the stream, with lignin phenol data indicating mobilisation of fresh DOC derived from woody vegetation in the upper catchment. This study shows that peatland catchments produce significant volumes of aromatic DOC and that photoreactivity of this DOC is greatest in headwater streams; however, an improved understanding of water residence times and DOC input–output along the source to sea aquatic pathway is required to determine the fate of peatland carbon.
Global gridded crop model evaluation: benchmarking, skills, deficiencies and implications
Authors: Müller Christoph , Elliott Joshua , Chryssanthacopoulos James , Arneth Almut , Balkovic Juraj , Ciais Philippe , Deryng Delphine , Folberth Christian , Glotter Michael , Hoek Steven , Iizumi Toshichika , Izaurralde Roberto C. , Jones Curtis , Khabarov Nikolay , Lawrence Peter , Liu Wenfeng , Olin Stefan , Pugh Thomas A. M. , Ray Deepak K. , Reddy Ashwan , Rosenzweig Cynthia , Ruane Alex C. , Sakurai Gen , Schmid Erwin , Skalsky Rastislav , Song Carol X. , Wang Xuhui , de Wit Allard , Yang Hong
Published: April 2017

Abstract. Crop models are increasingly used to simulate crop yields at the global scale, but so far there is no general framework on how to assess model performance. Here we evaluate the simulation results of 14 global gridded crop modeling groups that have contributed historic crop yield simulations for maize, wheat, rice and soybean to the Global Gridded Crop Model Intercomparison (GGCMI) of the Agricultural Model Intercomparison and Improvement Project (AgMIP). Simulation results are compared to reference data at global, national and grid cell scales and we evaluate model performance with respect to time series correlation, spatial correlation and mean bias. We find that global gridded crop models (GGCMs) show mixed skill in reproducing time series correlations or spatial patterns at the different spatial scales. Generally, maize, wheat and soybean simulations of many GGCMs are capable of reproducing larger parts of observed temporal variability (time series correlation coefficients (r) of up to 0.888 for maize, 0.673 for wheat and 0.643 for soybean at the global scale) but rice yield variability cannot be well reproduced by most models. Yield variability can be well reproduced for most major producing countries by many GGCMs and for all countries by at least some. A comparison with gridded yield data and a statistical analysis of the effects of weather variability on yield variability shows that the ensemble of GGCMs can explain more of the yield variability than an ensemble of regression models for maize and soybean, but not for wheat and rice. We identify future research needs in global gridded crop modeling and for all individual crop modeling groups. In the absence of a purely observation-based benchmark for model evaluation, we propose that the best performing crop model per crop and region establishes the benchmark for all others, and modelers are encouraged to investigate how crop model performance can be increased. We make our evaluation system accessible to all crop modelers so that other modeling groups can also test their model performance against the reference data and the GGCMI benchmark.
A systematic examination of the relationships between CDOM and DOC in inland waters in China
Authors: Song Kaishan , Zhao Ying , Wen Zhidan , Fang Chong , Shang Yingxin
Published: April 2017

Abstract. Chromophoric dissolved organic matter (CDOM) plays a vital role in the biogeochemical cycle in aquatic ecosystems. The relationship between CDOM and dissolved organic carbon (DOC) has been investigated, and the significant relationship lays the foundation for the estimation of DOC using remotely sensed imagery data. An algorithm has been developed to retrieve DOC via CDOM absorption (aCDOM) at 275 and 295 nm for coastal waters, but it is still unclear for the relationship between DOC and aCDOM in other types of waters. The current study examined the samples from freshwater lakes, saline lakes, rivers and streams, urban water bodies, and ice-covered lakes in China. The regression model slopes for DOC versus aCDOM(275) ranged from extreme low 0.33 (highly saline lakes) to 1.03 (urban waters) and 3.13 (river waters). The low values were observed in saline lake waters and waters from semi-arid or arid regions where strong photo-bleaching is expected due to thin ozone layers, less cloud cover, longer water residence time and daylight hours. In contrast, high values were found in waters developed in wetlands or forest in Northeast China, where massive organic matter was transported from catchment to waters. The study also demonstrated that stronger relationships between CDOM and DOC were revealed when aCDOM(275) were sorted by the ratio of aCDOM(250) to aCDOM(365), which is a tracer for the CDOM absorption with respect to its composition, and the determination of coefficient of the regression models ranged from 0.78 to 0.99 for different groups of waters. Our results indicated the relationships between CDOM and DOC are variable for different inland waters, and therefore remote sensing models for DOC estimation through linking with CDOM absorption need to be tailored according to water types.
The dynamics of the carbon dioxide system in the outer shelf and slope of the Eurasian Arctic Ocean
Authors: Pipko Irina I. , Pugach Svetlana P. , Semiletov Igor P. , Anderson Leif G. , Shakhova Natalia E. , Gustafsson Örjan , Repina Irina A. , Spivak Eduard A. , Charkin Alexander N. , Salyuk Anatoly N. , Shcherbakova Kseniia P. , Panova Elena V. , Dudarev Oleg V.
Published: April 2017

Abstract. The Arctic now is undergoing dramatic changes, which cover the entire range of natural processes; from extreme increases in the temperatures of air, soil, and water, to changes in the cryosphere, the biodiversity of Arctic waters, and land vegetation. Small changes in the largest marine carbon pool, the dissolved inorganic carbon pool, can have profound impact on the carbon dioxide (CO2) flux between the ocean and the atmosphere, and the feedback of this flux to climate. Knowledge of relevant processes in the Arctic seas improves the evaluation and projection of the carbon cycle dynamics under conditions of rapid climate change. Investigation of the CO2 system in the outer shelf and continental slope waters of the Eurasian Arctic seas (the Barents, Kara, Laptev, and East Siberian seas) during 2006, 2007, and 2009 revealed a general trend in the surface water pCO2 distribution, which manifested as an increase in pCO2 values eastward. Existence of this trend was determined by different oceanographic and biogeochemical regimes in the western and eastern parts of the study area; the trend is likely increasing due to a combination of factors determined by contemporary change in the Arctic climate, each change in turn evoked a series of synergistic effects. A high-resolution in situ investigation of the carbonate system parameters of the four Arctic seas was carried out in the warm season of 2007, which was characterized by the next-to-lowest historic sea ice extent in the Arctic Ocean to that date. The study showed the different responses of the seawater carbonate system to the environment changes in the western vs. the eastern Eurasian Arctic seas. The large open, highly-productive water area in the northern Barents Sea enhances atmospheric CO2 uptake. In contrast, a growing CO2 evasion occurs in the outer shelf and slope waters of the East Siberian Arctic seas as a result of the increasing influence of river runoff and degradation of terrestrial organic matter, in combination with the high surface-water temperature due to the warm air temperature and decreasing albedo during sea ice free conditions. This investigation shows the importance of processes that vary on small scales, both in time and space, for estimating the air-sea exchange of CO2. It stresses the need for high-resolution coverage of ocean observations as well as time series. Furthermore, time series must include multi-year studies in the dynamic regions of the Arctic Ocean during these times of environmental change.
Evaluation of hospital staff’s perceived quality of librarian-mediated literature searching services
Authors: McKeown Sandra , Konrad Shauna-Lee , McTavish Jill , Boyce Erin
Published: April 2017

Objective: The research evaluated the perceived quality of librarian-mediated literature searching services at one of Canada’s largest acute care teaching hospitals for the purpose of continuous quality improvement and investigation of relationships between variables that can impact user satisfaction.Methods: An online survey was constructed using evidence-based methodologies. A systematic sample of staff and physicians requesting literature searches at London Health Sciences Centre were invited to participate in the study over a one-year period. Data analyses included descriptive statistics of closed-ended questions and coding of open-ended questions.Results: A range of staff including clinicians, researchers, educators, leaders, and analysts submitted a total of 137 surveys, representing a response rate of 71%. Staff requested literature searches for the following “primary” purposes: research or publication (34%), teaching or training (20%), informing a policy or standard practice (16%), patient care (15%), and “other” purposes (15%). While the majority of staff (76%) submitted search requests using methods of written communication, including email and search request forms, staff using methods of verbal communication, including face-to-face and telephone conversations, were significantly more likely to be extremely satisfied with the librarian’s interpretation of the search request (p=0.004) and to rate the perceived quality of the search results as excellent (p=0.005). In most cases, librarians followed up with staff to clarify the details of their search requests (72%), and these staff were significantly more likely to be extremely satisfied with the librarian’s interpretation of the search request (p=0.002).Conclusions: Our results demonstrate the limitations of written communication in the context of librarian-mediated literature searching and suggest a multifaceted approach to quality improvement efforts. This article has been approved for the Medical Library Association’s Independent Reading Program.
Knowledge of journal impact factors among nursing faculty: a cross-sectional study
Authors: Kumaran Maha , Ha Chau
Published: April 2017

Objective: The research assessed nursing faculty awareness and knowledge of the journal impact factor (JIF) and its impact on their publication choices.Methods: A qualitative cross-sectional questionnaire was developed using Fluid Survey and distributed electronically to nursing faculty and instructors at three post-secondary institutions in Saskatchewan. Data were collected on place and status of employment, knowledge and awareness of JIFs, and criteria used to choose journals for publication.Results: A total of forty-four nursing faculty and instructors completed the questionnaire. The authors found that faculty lack awareness or complete understanding of JIFs and that JIFs are not the most important or only criterion used when they choose a journal for publication.Conclusions: There are various reasons for choosing a journal for publication. It is important for librarians to understand faculty views of JIFs and their criteria for choosing journals for publication, so that librarians are better equipped to guide researchers in considering their academic goals, needs, and personal values.