bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of B-2-C Social Media Communication in Germany
Authors: Linke Knut , Friedrich Torben
Published: May 2018

In this research paper, social media marketing activities of social media accounts from German business are analyzed for the social networks Facebook, Twitter, Instagram, Xing and LinkedIn. As research objects were the context of the interaction, the used and targeted social network functionalities and the behavior of the companies selected. The selection of social media accounts for the research included companies which are currently member from the stock market indices DAX and MDAX, additional online and offline retail business, successful German sports clubs, celebrities and others businesses. Also and to be sure to evaluate high-class social media marketing, the German social media award winners from 2015-2017 were analyzed. Out of the results of those two analyses, the results were derivate. The results display different usage approaches between the researched networks and the business fields. As result of the research, several contexts approaches for social media posts are defined. The results contain suggestions for the standardization of those contexts and the different approaches how functions from social networks can be used for user interactions. That includes the targeted reactions and standardized reactions of user interactions.
Dark Leadership Impact on Psychological Well-being and Work-Family Conflict: Implications for Project Success of Bahrain Companies
Authors: Abdo Saleh Hussein Ghaleb , Hu Wang , Abdo Hassan Hesham Mohammed , Khudaykulova Madina
Published: May 2018

This paper examines dark personality traits of leaders involved in management and proposes a conceptual framework for future studies. Based on the personality characteristics identified using Hogan Development survey, the influence of personality traits is hypothesized to affect the well-being of employees and consequently, business success. The study shows a negative relationship between the personality traits of leaders and the psychological well-being of employees and work-family conflict. According to the developed concept, there is a negative impact on business and project success due to the work-life conflict and psychological well-being of employees supervised by project leaders with a negative personality. Most of the studies in this area has focused on identifying the positive aspects of leadership, thus limiting the discussion on the implication of dark leadership. The originality of this paper can be described in the context of research on project leaders, whose negative traits are linked towards business and project failure. This dissertation contributes to leadership literature by identifying the significance of negative personality traits and by presenting the link to business failures.
The Global Learning Distinction: an Experiential Learning Research Project
Authors: Rego Michelle
Published: May 2018

The purpose of this paper is to demonstrate the importance of integrating global learning and culturally-responsive teaching as part of a University curriculum to prepare graduates to enter a global workforce. According to the Association of American Colleges and Universities (AAC&U), global learning programs are an important aspect of culturally responsive teaching which help students to “understand and engage the diversities and commonalities among the world’s peoples, cultures, nations, and regions” (AAC&U, 2018). The objective of this experiential learning project, implemented at the College of Business at Johnson & Wales University in Providence, RI, USA, was to research ways to engage students in active global learning both inside and outside of the classroom. Specifically, the problem being explored included needs to assess student attitudes toward global learning (1), understand perceived benefits of a Global Learning Distinction program (2), and identify an opportunity for students to get involved in the promotion of this program prior to the full launch in 2018 (3). Focus group research results are discussed and recommendations for future research in Global Learning.
Alteraciones en la superficie ocular y la película lagrimal en pacientes con conjuntivitis alérgica
Authors: Sánchez Calderón Leidy Viviana , González Díaz Luis Miguel , Rodríguez Martha Fabiola
Published: May 2018

Introducción: la conjuntivitis alérgica involucra una serie de mediadores inflamatorios e inmunológicos que afectan la estructura y fisiología de la unidad funcional lagrimal. Objetivo: Determinar las alteraciones en la superficie ocular y película lagrimal en pacientes con conjuntivitis alérgica. Materiales y métodos: se estudiaron tres grupos de 20 ojos de pacientes con conjuntivitis alérgica, 20 ojos sin patología ocular evidente, 20 ojos con ojo seco. Los pacientes y controles acudieron a la Clínica de Optometría de la Universidad de La Salle y firmaron el consentimiento informado antes de iniciar la investigación. Se realizó diagnóstico clínico y las siguientes pruebas: test de Schirmer 2, test de TBUT, biomicroscopía con tinción de fluoresceína y rosa de bengala, y citología de impresión conjuntival. Resultados: el 85% de los pacientes con conjuntivitis alérgica fue positivo para rosa de bengala, el 50% presentó metaplasia escamosa y el 5% tinción corneal positiva con fluoresceína. De estos pacientes el 82,3% presentó alteración en el TBUT y el 23,5% en el test de Schirmer. Conclusiones: la mayoría de los pacientes alérgicos presentan alteraciones en el epitelio conjuntival y disminución en la calidad de la película lagrimal. El daño del epitelio conjuntival incide en la estabilidad de la película lagrimal.
Estrabismos convergentes y divergentes en niños
Authors: Figueroa O. Luisa Fernanda , López Aguirre Yolanda
Published: May 2018

In the visual assessment of pediatric patients is essential to determine the ocular alignment, and to generate further ruled strabismus amblyopia, binocular vision loss. The esotropia is considered the most common type of strabismus in children, accounting for more than 50% of the deviations, whose management may be surgical or optical prescription according to their origin. The exotropia are rare before six months, usually starting intermittently and become constant, are associated with convergence insufficiency and abnormal sensory correspondence, depending on their size and permanence, are treated with orthoptics or surgery.
Importancia del manejo estadístico adecuado de datos refractivos
Authors: García Lozada Diana
Published: May 2018

Biostatistics is the application of statistical tools to biological and health sciences and may be descriptive or inferential; their application is essential to quantitative research. It’s important to generate optometric research in Colombia, not only descriptive but also analytical and experimental, with the appropriate application of parametric and nonparametric statistical procedures; for this purpose it’s important, since the methodology of the studies, to consider adequately the classification of the variables or characteristics under observation. This article suggests that for studies that include analysis of refractive techniques such retinoscopy, autorefraction or subjective, measurements must be taken in the traditional form (sphere, cylinder and axis) and then categorized in the most appropriate level in each case (nominal, ordinal, numeric) in order to apply statistical techniques that allow to give an adequate management of data and to reach valid and reliable conclusions. Thus, the results of research conducted in our country about refraction methods may be compared with those carried out in countries like the United States, Australia or UK.
More than the shadow of a doubt: dream theory and the impersonation of saints by angels
Authors: Krausmuller Dirk
Published: May 2018

This brief article makes the case that the
'uncritical' acceptance of the real presence of saints in dreams by the
participants of the Second Council of Nicaea did not reflect the usual attitudes
of the Byzantine elite. It shows that earlier and later writers denied such
presence through recourse to dream theory, which attributed all 'good' dreams
to the agency of angels.
Linear Algebra Continuous Dynamic Control for WMR
Authors: A Sebastian
Published: May 2018

A trajectory tracking controller for wheeled mobile robot (WMR) is presented in this paper. The approach is based on the dynamic model of a nonholonomic mobile robot. The non linear dynamic model is used to find the expression of the control actions which make the robot follow a desired trajectory. The methodology for controller design is based in Linear Algebra theory. Experimental results in a Pioneer 3DX mobile robot are presented and compared with other approach of the literature.
Fen Bilgisi Öğretmen Adaylarının E. Hubble’ın “Kırmızıya Kayma Yasası” Çerçevesinde Bilgi ve Bilişsel Süreç Yeterliklerinin İncelenmesi
Authors: AYDIN Nilgün , AYDIN Abdullah
Published: May 2018

Bu çalışmanın amacı, Hubble’ın “Kırmızıya Kayma
Yasası” çerçevesinde test oluşturularak fen bilgisi öğretmen adaylarının bilgi
ve bilişsel süreç yeterliklerinin incelenmesidir. Araştırmada nitel durum
çalışması deseni kullanılmıştır. Çalışmanın örneklemini Kırıkkale Üniversitesi,
Eğitim Fakültesi, Fen Bilgisi Eğitimi Anabilim Dalı’nda öğrenim gören 90
öğretmen adayı oluşturmaktadır. Verilerin elde edilmesinde 5 soruluk Bilişsel
Süreç Testi (BST) oluşturulmuştur. Öğretmen adaylarının verdikleri cevaplar
kodlanarak frekans ve yüzde hesaplamaları yapılmış, tablolara ve grafiklere
işlenmiştir. Elde edilen sonuçlara göre; öğretmen adaylarının, açıklanan fizik
yasasını matematiksel eşitlik olarak yazmada zorluk yaşamalarına karşın
eşitliğin grafiğini çizmede bu zorluğu yaşamadıkları, görünür ışık bölgesiyle
ilgili ön bilgilerini hatırlamada zorlandıkları, doğru olarak hatırlayanlardan
bir kısmının yorum yapmada zorlandıkları, ayrıca büyük çoğunluğunun büyük
patlama (big bang) ya da evrenin genişlemesi kuramına ulaşamadıkları
görülmüştür. Elde edilen sonuçlar, büyük oranda, örneklemdeki öğretmen
adaylarının bilgi ve bilişsel süreç yeterliklerinin istenilen seviyede
olmadığını ortaya koymuştur. Sonuçlar ışığında, durumun iyileştirilmesine katkı
sağlayacak öneriler sunulmuştur.
Acceso y graduación en la formación profesional universitaria
Authors: Espinoza Babilón José
Published: May 2018

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Annexins in Translational Research: Hidden Treasures to be Found
Authors: Schloer Sebastian , Pajonczyk Denise , Rescher Ursula
Published: May 2018

The vertebrate annexin superfamily (AnxA) consists of 12 calcium (Ca2+) and phospholipid binding proteins which share a high structural homology. In keeping with this hallmark feature, annexins have been implicated in the Ca2+-controlled regulation of membrane events. In this review, we discuss several themes of potential therapeutic value, namely the regulation of the immune response and the control of tissue homeostasis, that repeatedly surface in the annexin action profile. Our aim is to identify and discuss those annexin properties which might be exploited from a translational science and specifically clinical point of view.
Characteristics of Diablo-like Wind conditions in Northern California Based on a Climatology from Surface Observations
Authors: Smith Craig , Hatchett Benjamin , Kaplan Michael
Published: May 2018

Diablo winds are dry and gusty north-northeasterly downslope windstorms that affect the Northern California. On the evening of October 8, 2017, Diablo winds contributed to the ignitions and rapid spread of the “Northern California Firestorm”, including the Tubbs Fire, which burned 2,800 homes in Santa Rosa, resulted in 22 fatalities and $1.2B USD in damages. We analyzed 18 years of data from a network of surface meteorological stations and show that Diablo winds tend to occur overnight through early morning in Fall, Winter and Spring. Conditions similar to Diablo winds occur commonly in the Sierra Nevada Mountains in addition to the area North of the San Francisco Bay Area including the Northern Coastal Ranges. Diablo winds are characterized by high wind speeds and low relative humidity, but they tend to neither be warmer than climatology nor do they have a higher gust factor, or ratio of wind gusts to mean wind speeds, than climatology.
The Life and Death of the Hiatus Consistently Explained
Authors: Rypdal Kristoffer
Published: May 2018

The main features of the instrumental global mean surface temperature (GMST) are reasonably well described by a simple linear response model driven by anthropogenic, volcanic and solar forcing. This model acts as a linear long-memory filter of the forcing signal. The physical interpretation of this filtering is the delayed response due to the thermal inertia of the ocean. This description is considerably more accurate if El Ni\~{n}o Southern Oscillation (ENSO) and the Atlantic Multi-decadal Oscillation (AMO) are regarded as additional forcing of the global temperature and hence subject to the same filtering as the other forcing components. By considering these as predictors in a linear regression scheme, more than 92\% of the variance in the instrumental GMST over the period 1870-2017 is explained by this model, and in particular all features of the 1998 -- 2015 hiatus, including its death. While the more prominent pauses during 1870 -- 1915 and 1940 -- 1970 can be attributed to clustering in time of strong volcanic eruptions, the recent hiatus is an unremarkable phenomenon that is attributed to ENSO and a small contribution from solar activity.
ANDRAGOGI YANG HUMANIS
Authors: Widyaningrum Retno
Published: May 2018

Teaching is principally based on pedagogi and andragogi. Pedagogi is normally used to teach young learners, while andragogi is used for adults. However in practice pedagogi which tends to transfer knowledge and make passive learning is often used for adults. This article discusses how andragogi can be used to make teaching human and how to humanize learners by using andragogi. It is believed that andragogi can create active learning in which the learners can meet their needs such as esteem and self actualization. Discussing humanistic andragogi from different views this article concludes its importance and advantages in life long learning and provides some suggestion how to carry out humanistic andragogi for active, creative,innovative and joyfull learning.
Modeling and Optimization of Friction Stir Welding Parameters for Joining Dissimilar Aluminum Alloys
Authors: Abd Elnabi Mohamed Mohamed , Osman Tarek Abd Elsadek , El Mokadem Alaa Eldeen , ElshalakanyÂ Abou Bakr
Published: May 2018

The objectives of this work are to optimize the process parameters on the mechanical properties (ultimate tensile strength (UTS) and ductility) of dissimilar joints between AA5454 and AA7075 produced by friction stir welding and to determine which of them is significant by using Taguchi L16 optimization method. Seven parameters at two levels were selected in this study. The selected parameters are tool rotational speed, traverse speed, pin profile (based on taper angle), D/d ratio, tool tilt angle, plunge depth, and base metal location. Then, mathematical models are built as function of significant parameters/ interactions using Response Surface Methodology. The results of this work showed that the rotational speed, traverse speed, D/d ratio and plunge depth are significant parameters in determining UTS (Mean, Signal to noise ratio (S/N)) at different confidence levels, but pin profile, location of base metal and tool tilt angle are insignificant parameters at any confidence levels. The traverse speed has the highest contribution to the process for UTS about 18.577 % and 16.943 % for S/N ratio and mean, respectively. The accuracy of the models according to the UTS is 97.678 % and 99.56 %for mean and S/N ratio, respectively. The maximum joint efficiency, compared to the strength of the AA5454, is 85.3%.
Automatic systems for heat detection in cows as a tool for improving herd management
Authors: JAŚKOWSKI JĘDRZEJ M. , KMIECIK JULITA , KIERBIĆ ALEKSANDRA , HERUDZIŃSKA MAGDALENA , WOŹNA-WYSOCKA MAGDALENA
Published: May 2018

There are at least several ways of detecting bovine heat, which vary in accuracy, as well as in the effort and cost associated with the implementation and operation of equipment designed for this purpose. Heat in cows can be most easily detected by thorough and systematic observation of animals in the herd. Other methods include the measurements of vaginal mucosal resistance, the fitting of balloons with paint at the base of the tail or on the back, temperature measurements in the vagina, rumen and milk, and determination of progesterone levels in milk and blood. Currently, controlled breeding programmes, including timed artificial insemination (TAI) and automated estrus detection (AED) or activity monitoring system (AMS), are routinely introduced in high-performance dairy herds. Most of the commercially available heat detection devices are based on accelerometers or pedometers. These devices are capable of detecting heat in 81.4% to 91.3% of cows. The sensitivity of heat detection was 58.9% for accelerometers (Heatime), 63.3% for pedometers (SAE Afikim, Kibbutz Afikim, Israel), 56.7% for KaMaR markers and 35.9% for heat detectors (Scratchcard). When two of the three systems were combined (different combinations), the sensitivity increased to 75.9%. Similarly, after adding visual detection, sensitivity increased to 96% and specificity to 90% (for visual observation combined with AMS). Activity monitoring systems are a proven tool for improving the management of cows. They are an alternative to reproductive management based solely on traditional methods of detecting ovulation or hormone programmes (TAI) and they respect the well-being of animals. It seems, however, that further improvement in cows’ fertility on industrial cattle farms will be achieved by combining several different methods of heat detection and synchronization, rather than by using a single modern heat detection system..
Impact on the Fate of Toxic Contaminants in the Toronto Waterfront — Should the Toronto Main Sewage Treatment Plant Outfall Be Moved Farther Offshore?
Authors: Halfon Efraim
Published: May 2018

A fate model, TOXFATE, is coupled with a hydrodynamic model of the waters off the Toronto waterfront, Lake Ontario. The Toronto waterfront is here defined as a rectangular area, 48 km long by 10 km wide, of the lake delimited on the west by Etobicoke Creek and in the east by the Rouge River. Data were collected in 1987 in support of the Toronto Main Sewage Treatment Plant (STP) pilot site study, Municipal and Industrial Study for Abatement (MISA). It provides an excellent baseline database. The object of the fate-modeling study is to assess the change in organics concentration if loadings from the Main STP and other local sources were changed or the outfall location moved farther offshore. Loadings of contaminants from local sources in the Toronto waterfront area are between 0.5% to 25% of contaminants that enter Lake Ontario from other sources. Results show that if sources of local loadings were reduced, changes in water concentrations would be noticeable within 1 to 2 kilometres from shore. Only a small area of the waterfront is affected directly by local sources since waters in the Toronto waterfront area are replaced approximately every 9 days (as computed from the hydrodynamic simulation). Therefore, toxic contaminants that enter from local sources are readily dispersed in the rest of the lake. Simulations also show that the extension of the Toronto Main STP outfall to a new location farther offshore will result in a dilution of toxic contaminants 10 times greater than that obtained at the present STP outfall. A complete set of figures, including an interactive analysis of the computer simulations, is available on the Web site www.butx.com/toronto.
Removal of Taste and Odour Compounds by Conventional Granular Activated Carbon Filtration
Authors: Ridal Jeff , Brownlee Brian , McKenna Gerry , Levac Norman
Published: May 2018

In recent years, musty-earthy tastes in drinking water have become a seasonal problem (September to November) for communities that draw their water from the upper St. Lawrence River. The source of the problem is attributed to the presence of geosmin and 2-methylisoborneol (MIB) at concentrations ranging from 5 to 60 ng/L. In 1997 and 1998, the Cornwall Water Purification Plant added granular activated carbon (GAC) to conventional gravity filters to control taste and odour compounds. We report on a study to test the efficiency of these conventional GAC-capped filters to reduce geosmin and MIB concentrations in finished water as a function of filter age, initial chlorine residual and contact time. GAC–capped filters removed on average 60% of the MIB and 80% of the geosmin from the source water after 2 and 12 months of filter operation. However, testing after 24 months operation showed reduced efficiency. Amounts removed ranged between 13 and 20% (15% average) for MIB and 50 to 57% (54% average) for geosmin in these filters. Testing also suggested that filter efficiency was greater with longer contact times and with higher chlorine residuals (in the range 0.1 to 0.6 mg free Cl2/L). In addition to carbon age, chlorine residual and contact time, flow channelization and slow release of the taste and odour compound load (particularly MIB) from the GAC bed may affect apparent filter efficiency.
Evaluation of Particle Removal at Water Treatment Plants in Nova Scotia
Authors: Eisnor John D. , O'Leary Kevin C. , Gagnon Graham A.
Published: May 2018

The physical removal of colloidal particles, microorganisms and other particulate material is an important objective for drinking water utilities. Because of the low concentration of suspended material in drinking water, turbidity has traditionally been the main water quality parameter for assessing particle removal in water treatment. However, particle counting is becoming increasingly popular for process optimization in conventional plants and for monitoring membrane integrity in new microfiltration and/or ultrafiltration plants. The research describes a survey of particle removal at four water treatment plants in Nova Scotia. Turbidity and particle counts were analyzed in both raw and filtered water. The treatment processes of the four plants was compared using particle count data. The results indicate that particle counters are able to detect decreases in filter performance earlier than turbidimeters.
An Overview of Substances Present in Canadian Aquatic Environments Associated with Endocrine Disruption
Authors: Hewitt Mark , Servos Mark
Published: May 2018

Numerous environmental contaminants have been associated with the ability to affect the endocrine status of animals and with the potential to elicit effects on individuals or populations in Canadian aquatic environments. Potential endocrine disrupting substances (EDS) consist of almost every class of environmental contaminants reported to date, including industrial chemicals, historical and current use pesticides, metals, and different classes of natural products. It has been difficult to establish cause-and-effect relationships with potential EDS for several reasons: i) the diversity of ways that chemicals can influence endocrine systems challenges efforts to characterize chemicals that can cause endocrine responses, ii) many responses in aquatic biota have been associated with complex mixtures where the causative agents remain unidentified, and iii) most literature information deals with mammalian studies using pure compounds so there is considerable uncertainty regarding extrapolation to aquatic species and efficacy of environmental concentrations. An overview of the literature on EDS, specific to exposure within Canadian aquatic environments, is presented to emphasize the diversity and complexity of chemicals capable of altering endocrine function.
Sediment Management: Ecological and Ecotoxicological Effects Must Direct Actions
Authors: Krantzberg Gail , Zarull Michael A. , Hartig John H.
Published: May 2018

The need for guidance on the bioassessment and management of contaminated sediment has been articulated by Remedial Action Plan practitioners, the International Joint Commission, scientists, and managers in many jurisdictions. Encouragingly, a convergence of opinion, on what constitutes a comprehensive sediment assessment, is beginning. However, there continues to be a need for methods to interpret and integrate multiple pieces of information on sediment chemistry, biological information from field monitoring and laboratory sediment bioassessment in an ecologically meaningful way. This paper recommends an approach to comprehensive sediment bioassessment that is driven by the need to rehabilitate “beneficial uses” as described in the Great Lakes Water Quality Agreement. The paper also highlights advances in data interpretation that are facilitating he development of sediment management strategies.
Approche géomatique pour simuler l'érosion hydrique et le transport des sédiments à l'échelle des petits bassins versants
Authors: Duchemin Marc , Lachance Marius , Morin Guy , Lagacé Robert
Published: May 2018

L'existence de problèmes d'érosion hydrique à différents endroits d'un bassin versant se manifeste souvent par la présence d'une quantité excessive de sédiments en suspension dans les cours d'eau. L'évaluation indirecte de l'érosion par la mesure des sédiments en suspension transportés à l'exutoire des bassins versants permet ainsi d'avoir une bonne idée de l'impact environnemental des activités agricoles. Il s'avère toutefois essentiel, dans une perspective de gestion de la qualité de l'eau à l'échelle d'un bassin versant, de pouvoir estimer l'érosion hydrique et le transport des sédiments en suspension afin d'identifier les zones problématiques. Cette estimation implique la manipulation d'une somme considérable d'informations pour décrire l'environnement du bassin versant et l'emploi de modèles mathématiques complexes pour simuler les processus hydrologiques et sédimentologiques en jeu. Le recours aux modèles informatiques d'érosion hydrique et aux systèmes d'information géographique (SIG) est alors de mise. Cet article présente le développement et l'application d'une approche géomatique de simulation qui implique l'utilisation conjointe du modèle hydrologique CEQUEAU, du modèle d'érosion MODÉROSS et du système d'information géographique IDRISI. Plus précisément, cet article présente de quelle façon le progiciel CEQÉROSS a été utilisé pour prédire le comportement hydrosédimentologique d'un petit bassin versant agricole du Québec. Les charges sédimentaires totales simulées à l'exutoire du bassin versant de Lennoxville s'élevaient à 27,5 tonnes et 54,1 tonnes pour les années hydrologiques 1991–1992 et 1992–1993 respectivement. Ces valeurs se comparent avantageusement aux charges sédimentaires totales de 30,3 tonnes et 51,3 tonnes observées durant ces mêmes périodes. Les résultats obtenus montrent également que la nature épisodique du transport des sédiments en suspension à l'exutoire du bassin versant de Lennoxville pendant la période 1991–1993 a été bien reproduite par CEQÉROSS. L'approche géomatique proposée est suffisamment conviviale et fiable pour s'inscrire à l'intérieur d'un ensemble d'outils de gestion agroenvironnementale.
Kinetics and Activation Parameters for the Alkaline Aqueous Rearrangement of Trichorfon [O,O-Dimethyl-(2,2,2-Trichloro-1-Hydroxyethyl) Phosphonate] to Dichlorvos [O,O-Dimethyl-O-(2,2-Dichloroethenyl)Phosphate]
Authors: Dust Julian M. , Warren Christopher S.
Published: May 2018

The kinetics of the alkaline rearrangement of O,O-dimethyl-(2,2,2-trichloro-1- hydroxyethyl)phosphonate, (trichlorfon, 1), the active insecticidal component in such formulations as Dylox, was followed at 25±0.5°C by high pressure liquid chromatography (UV-vis detector, 210 nm). The rearrangement product, O,Odimethyl- O-(2,2-dichloroethenyl)phosphate (dichlorovos, 2), which is a more potent biocide than trichlorfon, undergoes further reaction, and the kinetics, consequently, cannot be treated by a standard pseudo-first-order plot. A two-point van't Hoff (initial rates) method was used to obtain pseudo-first-order rate constants (kѱ) at 25, 35 and 45°C: 2.6 × 10-6, 7.4 × 10-6 and 2.5 × 10-5 s-1, respectively. Arrhenius treatment of this data gave an activation energy (Ea) of 88 kJ·mol-1 with a pre-exponential factor (A) of 5.5 × 109 s-1. Kinetic trials at pH 8.0 using phosphate and tris buffer systems show no buffer catalysis in this reaction and indicate that the rearrangement is subject to specific base catalysis. Estimates are reported for pseudo-first-order half-lives for trichlorfon at pH 8.0 for environmental conditions in aqueous systems in the Corner Brook region of western Newfoundland, part of the site of a recent trichlorfon aerial spray program.
Prévision de l'adsorption de molécules organiques en solution aqueuse en fonctions de quelques caractéristiques physico-chimiques de charbons actifs
Authors: Baudu Michel , Guibaud Gilles , Raveau David , Lafrance Pierre
Published: May 2018

La production d'eau potable nécessite parfois une filtration sur charbon actif en vue d'éliminer des micropolluants organiques. Afin de développer un modèle prévisionnel de la durée de vie de ces filtres, il est nécessaire de bien connaître les caractéristiques des charbons influençant l'adsorption. Des caractéristiques de la structure physique (porosité et surface) et chimiques (fonction de surface), le potentiel zêta et les constantes thermodynamiques de neuf charbons actifs ont été déterminées et des essais de corrélation ont indiqué une certaine ligne de conduite pour l'utilisation de charbons de différentes origines. Des cinétiques et des isothermes d'adsorption de l'atrazine et du phénol ont été réalisées, ceci afin de mieux comprendre l'influence de la structure et des caractéristiques physico-chimiques des charbons sur les mécanismes d'adsorption. L'étude a mis en évidence les points suivants : (i) le nombre de sites primaires polaires d'adsorption augmente lorsque le nombre de fonctions acides augmente et lorsque le nombre de fonctions basiques diminue ; (ii) la capacité maximale d'eau adsorbée augmente avec la surface spécifique et diminue avec le nombre de fonctions acides du charbon ; (iii) l'adsorption de l'atrazine (molécule peu polaire) est en partie contrôlée par des paramètres physiques comme la surface spécifique ; (iv) les groupements polaires facilitent l'adsorption du phénol (molécule très polaire), et : (v) les valeurs du potentiel zêta sont difficiles à interpréter : la présence de groupements fonctionnels non déterminés pourrait intervenir sur les mécanismes d'adsorption.
Application of Faecal Sterol Ratios in Sediments and Effluents as Source Tracers
Authors: Marvin Chris , Coakley John , Mayer Tatiana , Brown Mitra , Thiessen Lina
Published: May 2018

An analytical method to determine faecal sterols was developed and applied to the analysis of samples including pig manure, sewage treatment plant sludge and combined sewer overflow effluent. Compounds including coprostanol (5β-cholestan-3β-ol), epicoprostanol (5β-cholestan-3α-ol), cholesterol (cholestan-5-en-3β-ol) and dihydrocholesterol (cholestanol, 5α-cholestan-3β-ol) were quantified in these source samples and their relative ratios calculated to investigate their potential application as source tracers. A mean coprostanol:epicoprostanol ratio of 7.6 ± 1.17 was calculated for pig manure samples from three Ontario livestock operations. This ratio was much lower (approximately 1.8) for sewage treatment plant sludge while the ratio for a combined sewer overflow effluent was very high (approximately 70). This approach, with the addition of physical measurements (e.g., current velocities) and meteorological data, may assist in determination of the influence of shore-based activities, including sewage treatment and livestock operations, on aquatic systems.
Heavy Metal Removal by the Waste Biomass of Penicillium chrysogenum
Authors: Skowroński Tadeusz , Pirszel Jacek , Skowrońska Barbara Pawlik
Published: May 2018

Metal sorption capacity of the granulated biosorbent derived from the waste biomass of Penicillium chrysogenum was examined. The potential metal sorption abilities of the biosorbent were estimated as the cation-exchange capacity, using a potentiometric titration. The total binding capacity, calculated for the pH range 3 to 8 was about 511 µeq/g dry weight. The granular biosorbent was capable of Cd, Zn, Cu and Pb binding. The kinetics of the heavy metal sorption were typical of the microbial dead biomass; metals were bound in the first few minutes. Sorption was a saturable process and the maximum sorption capacity, calculated from the Langmuir equation for the particular heavy metals was: 96 mg Pb; 21.5 mg Cd; 13 mg Zn and 11.7 mg Cu (per g dry weight). Optimum pH values for Cd, Zn and Cu sorption were about 7, while for Pb about 6. Heavy metal removal from different solutions was examined using the biosorption columns packed with P. chrysogenum, which efficiently removed Cd from 1 mM Cd solution, or Cd and Zn from the industrial wastewater. The studied biosorbent was capable of accumulating Cd and Zn even at the high Ca concentration.
Impact of Bleached Kraft Pulp Mill Effluent on the Nearshore Benthic Community of Jackfish Bay, Lake Superior
Authors: Sibley Paul K. , Dixon D. George , Barton David R.
Published: May 2018

We assessed the impact of bleached kraft pulp mill effluent on benthic invertebrate community structure in the shallow (1 m) nearshore waters of Jackfish Bay, Lake Superior. Duplicate benthic samples were collected from 0.5 m2 quadrats at twenty-three stations along two shorelines of Jackfish Bay up to 1800 m from the point of effluent discharge, and from a reference station located within the Jackfish Bay study area. Detrended correspondence analysis (DCA) revealed a gradient of stations on both shorelines which was strongly correlated with distance from effluent outfall and hence exposure to the effluent plume. Within this gradient were two distinct clusters of stations. The first cluster contained all but one station on both shores <300 m from the outfall; these stations receive constant exposure to the effluent and were dominated (>90%) by tubificids (Limnodrilus hoffmeisteri, Tubifex tubifex, T. ignotus and Spirosperma ferox) and the naidid Chaetogaster diaphanus. The second cluster contained all stations on both shores >300 m from the outfall; community structure at these stations was generally comparable to that at the reference site and was characterized by several species of Chironomidae, C. diaphanus and Nais barbata, and low numbers of several insect taxa. The results of this study show that benthic community structure in nearshore environments can be significantly impacted by pulp mill effluent and should be considered in monitoring assessments. At Jackfish Bay, such impacts appear to be restricted primarily to within the first 500 m of effluent discharge.
Natural and Constructed Wetlands in Canada: An Overview
Authors: Kennedy Gavin , Mayer Tatiana
Published: May 2018

A review of freshwater wetland research in Canada was conducted to highlight the importance of these ecosystems and to identify wetland research needs. Both natural and constructed wetland systems are discussed. Natural wetlands are an important part of the Canadian landscape. They provide the habitat for a broad variety of flora and fauna and contribute significantly to the Canadian economy. It is estimated that the total value derived from consumptive and non-consumptive activities exceeds $10 billion annually. The past decades have witnessed the continued loss and degradation of wetlands in Canada. In spite of recent protection, Canadian wetlands remain threatened by anthropogenic activities. This review shows that more research on fate and transport of pollutants from urban and agricultural sources in wetland systems is needed to better protect the health and to assure the sustainability of wetlands in Canada. Furthermore, improved knowledge of hydrology and hydrogeochemistry of wetlands will assure more effective management of these ecosystems. Lastly, better understanding of the effect of climate change on wetlands will result in better protection of these important ecosystems.

Constructed wetlands are man-made wetlands used to treat non-point source pollution. The wetland treatment technology capitalizes on the intrinsic water quality amelioration function of wetlands and is emerging as a cost-effective, environmentally friendly method of treating a variety of wastewaters. The use of wetland technology in Canada is, however, less common than in the U.S.A. A number of research needs has to be addressed before the wetland treatment technology can gain widespread acceptance in Canada. This includes research pertaining to cold weather performance, including more monitoring, research on design adaptation and investigation of the effects of constructed wetlands on wildlife.
Wastewater Sludge as a New Medium for Rhizobial Growth
Authors: Rebah Faouzi Ben , Tyagi Rajeshwar D. , Prévost Danielle , Surampalli Rao Y.
Published: May 2018

The objective of this study was to demonstrate that municipal and industrial wastewater sludges could be used as a sole raw material to sustain growth of rhizobia. Growth of two different groups of rhizobium (fast growing: Sinorhizobium meliloti, Rhizobium leguminosarum bv viciae; and slow growing: Bradyrhizobium japonicum and Bradyrhizobium elkanii) was tested on primary, secondary and mixed sludges obtained from different wastewater treatment plants. The results obtained in Erlenmeyer flasks indicated that slow- and fast-growing rhizobia grew well in sludge. Generally, the number of cells of rhizobia exceeds 1 × 109 cfu/mL in 72 h. The composition of sludges varies with the sludge type and origin. The sludge composition affected the generation time, cell yield and nodulation index. Higher solids concentration tended to give higher generation time. The high sludge metals concentration did not affect the growth kinetics of rhizobia. However, primary sludge could inhibit cell growth. Acid, alkaline and oxidative pre-treatments increased the primary sludge biodegradability and consequently the cell count of S. meliloti. Pre-treatment of pulp and paper sludge with NaOH enhanced the bacterial cell concentration to a maximum 1 × 1010 cfu/mL. Sludge pre-treatment decreased the generation time and reduced the process time.
Flow Rates Through Alum Coagulation and Activated Sludge Flocs
Authors: Gorczyca Beata , Ganczarczyk Jerzy
Published: May 2018

The liquid velocity inside alum and activated sludge flocs was calculated using the size, settling velocity and permeability of activated sludge flocs. The permeability of activated sludge flocs has been determined experimentally. The permeability of alum coagulation flocs was assumed to be half of the permeability of activated sludge flocs based on the size of the pores in these flocs. The average flow velocity inside an activated sludge floc was calculated to be 1575 µm/s, which is in the range of the flow experimentally measured inside biofilms at a distance of about 100 µm from the substratum by Beer et al. (1995). The flow inside an alum coagulation floc was calculated to be 318 µm/s. The flow velocity inside the same flocs estimated with Davies permeability model were 0.7 µm/s for activated sludge flocs and 20 µm/s for alum coagulation flocs. Therefore, the flow velocities estimated on the basis of experimentally determined permeability were much higher than the velocities calculated with Davies permeability model.

Davies permeability model assumes homogeneous distribution of porosity inside an aggregate. Direct observations made during the analysis of floc sections have proven this assumption to be wrong. Flocs have fractal structure and the models predicting their permeability should be based on this feature. Flow rates through alum and activated sludge flocs predicted on the basis of the fractal model of a floc compared well with experimental results.
A Comparison of Methods for Normalizing Residues of Organic Contaminants in Zebra Mussels (Dreissena polymorpha), with Implications for Biomonitoring Programs
Authors: Metcalfe-Smith Janice L. , Comba Michael E. , Kaiser Klaus L.E. , Solla Shane R. De
Published: May 2018

There has been little consistency to date in the method used to express concentrations of organic contaminants in zebra mussels collected from the Great Lakes. Concentrations have been reported on a wet whole (with shells), dry whole, wet soft tissue, dry soft tissue, and lipid weight basis. This study examined residues of organic contaminants in samples of zebra mussels collected from 24 sites in the lower Great Lakes and St. Lawrence River, to determine if the way in which the residues were normalized could affect the precision of estimated concentrations or the spatial trends observed. Variation in the moisture content of soft tissues was minimal, so normalizing to wet or dry soft tissue weight would yield consistent results. Moisture content of whole mussels was more variable, and relative proportions of soft tissues and shell vary with size, season and location—potentially confounding spatial trends. Lipid content also varies greatly among locations, seasons and years, and lipid-normalized residues were much more variable than residues normalized to whole or soft tissue weight. Furthermore, site-to-site trends based on lipid-normalized data did not always agree with those based on other components of the organism, and thus should not be interpreted in isolation.
Modelling Air-Water Exchange Process of Pentachlorophenol in the Aquatic Environment
Authors: Chi Jie , Huang Guo-Lan
Published: May 2018

To study the effects of the surface microlayer (SM) on the air-water exchange process of pentachlorophenol (PCP), simulated experiments were carried out in a microcosm containing air, water and sediment. A four-compartment (i.e., air, SM, water and sediment) fugacity model was successfully applied to the simulated experiments in the microcosm. Data obtained from the four-compartment model calculation yielded a more satisfactory fit with experimental results than the use of a model that does not address the effects of the SM compartment. Results of model calculation show that 97.8% of PCP is distributed to the water phase in the aquatic environment, and 82.2% PCP is removed by the advective outflow and biodegradation in the water phase. The results obtained demonstrate that the higher photodegradation rate of PCP in the SM reduces the concentration of PCP in the air phase.
Effectiveness of Isolated Pipeline Crossing Techniques to Mitigate Sediment Impacts on Brook Trout Streams
Authors: Reid Scott M. , Stoklosar Scott , Metikosh Serge , Evans Jim
Published: May 2018

Stream populations of brook trout (Salvelinus fontinalis) are sensitive to sediment-caused changes to habitat, i.e., increased embeddedness of bed material. The use of watercourse crossing techniques (dam and pump, and flume methods) that isolate the construction site by diverting flow around the crossing has often been promoted as a means of controlling the amount of sediment released, particularly for those watercourses with sensitive fish species or habitats. However, few case studies have evaluated the effectiveness of isolated crossing construction techniques to mitigate the effects of instream construction activities. We measured suspended sediment concentrations during six isolated pipeline crossings of brook trout streams in Minnesota, Nova Scotia and Ontario. In addition, sediment deposition rates, riffle habitats and fish abundance were monitored upstream and downstream of four of the crossings. Results of our monitoring studies indicate that isolated techniques can be very effective at: (1) minimizing increases to downstream suspended sediment concentrations during instream construction; and, (2) preventing sediment-induced effects on habitat and fish abundance downstream of pipeline water crossings. For sensitive watercourses, isolated crossing techniques are an effective alternative to trenchless crossing techniques (e.g., horizontal directional drilling).
Herbicides in Alberta Rainfall as Affected by Location, Use and Season: 1999 to 2000
Authors: Hill Bernard D. , Harker K. Neil , Hasselback Paul , Inaba Dan J. , Byers Susan D. , Moyer Jim R.
Published: May 2018

A study of herbicides in Alberta rainfall was conducted at 17 locations in 1999 and 18 locations in 2000. Rainfall samples (bulk deposition) were collected using a funnel and glass bottle at weekly to biweekly intervals from April to September. Samples were analyzed for 13 herbicides in 1999 and 19 herbicides in 2000 using a MSD-GC method. Herbicides were detected in the rainfall on most sample dates at every location. The herbicides detected in the highest amounts (in order) were: 2,4-D, MCPA, bromoxynil, dicamba and mecoprop. Detections were quite consistent between years. Herbicide amounts over the season were lowest at the remote locations (21–96 µg/m2 2,4-D), intermediate in the City of Lethbridge (82–109 µg/m2 2,4-D) and highest in the farming areas (44–315 µg/m2 2,4-D). The highest herbicide concentrations (17–53 µg/L 2,4-D) occurred when there was a small rainfall (0.1-0.2 mm) during the agricultural spraying season. Herbicide concentrations occasionally exceeded the Canadian Drinking Water Guidelines and frequently exceeded the Aquatic Life Guidelines. In general, herbicide levels in rainfall reflected agricultural use (sales) patterns. The highest 2,4-D detections occurred in southern Alberta, the highest MCPA detections were in central Alberta. In a side-by-side test, our funnel method of collecting rainfall yielded herbicide amounts that were nine times higher than a wet-only automated MIC sampler. Most previous Canadian studies used the MIC sampler and therefore may have underestimated levels of herbicides in rainfall. A more expansive study is needed to determine the levels of herbicides in rainfall across the Canadian Prairies.