bluuebunny/crossref_metadata_2025 huggingface dataset:
Human interface with safety instrumented systems in the chemical, petrochemical, oil and gas industries
Authors: Silva Elisio Carvalho
Published: December 2014

Industrial processes became safer with automation. However, when these systems fail, it can cause major accidents. Thus, it is fundamental for these systems to be installed and maintained to avoid failures that can be transformed into accidents. Random and systematic failures are failures of automation systems. The first are predictable, however the second are caused by human factors, hence, it is impossible to foresee them. Thus, it becomes necessary to have good human factor management to avoid these dangerous failures. This paper briefly discusses human errors and comes up with a management to avoid systematic failures, taking in consideration the types and behavior of the errors. Applying this management, it will reduce human errors and, therefore, systematic failures. These actions will enhance the safety of industrial processes.Keywords: Human errors. Automation. Safety. Management.
Indicadores de desempenho utilizados em beneficiadores de arroz: um estudo na região da Campanha-RS
Authors: Sonaglio Albano Claudio , Wohlenberg Janaina , Garcia Vitor Pires
Published: December 2014

A busca por maior competitividade está presente em todos os mercados. No setor do agronegócio, fortemente impactado por novas tendências globais (produtos e formas de produção), este fato é ainda mais importante. O setor orizicola é um importante segmento do agronegócio brasileiro, especialmente no estado do Rio Grande do Sul (RS). De outra parte a utilização de indicadores é recomendada como um importante aliado para o monitoramento dos fatores de produção, de forma a permitir que a organização alcance seus objetivos. Assim, o objetivo deste trabalho foi o de verificar como as organizações do setor orizicola da região da campanha do estado do RS utilizam os fatores de produção como forma de monitorar seus processos.Palavras-chave: Arroz. Indicadores. Monitoramento de produção.
Modelo conceitual para a introdução das práticas de sustentabilidade nas operações da indústria gráfica
Authors: Kai Dalton Alexandre , Pinheiro de Lima Edson , Gouvea da Costa Sergio Eduardo
Published: December 2014

Há uma preocupação mundial com o desenvolvimento global e isso tem obrigado as organizações a modificarem sua gestão e operações a fim de se manterem competitivas, até pela própria sobrevivência. Passar a desenvolver-se de forma sustentável significa ser economicamente viável, mudar cada operação com o propósito de diminuir ou mesmo não gerar resíduos, conservar energia e os recursos naturais, ser segura e não maléfica aos trabalhadores, comunidade e consumidores. Percebe-se que as empresas que compõem o setor gráfico brasileiro ainda não têm essa compreensão. O objetivo geral da pesquisa é propor um modelo conceitual, apoiado no Triple Bottom Line (3BL), para as práticas de sustentabilidade nas operações da indústria gráfica. Por meio de um processo de revisão bibliográfica, buscou-se examinar as particularidades das operações desta indústria, diversas visões sobre questões econômicas, ambientais e sociais envolvendo diretamente as operações. Com base no do modelo apresentado espera-se que possa ser aplicado, e que venha a tornar-se ser um ponto de partida, permitindo as empresas gráficas a adequarem seus modos de operação, adotando as melhores praticas sustentáveis, em favor do desenvolvimento sustentável.Palavras-chave: Indústria Gráfica. Gestão de Operações. Sustentabilidade. Desenvolvimento Sustentável.
TRIZ - inwentyczna metoda rozwiązywania problemów
Authors: Gajewski Andrzej
Published: December 2014

TRIZ is the theory of inventive problem solving (TIPS). It was elaborated by a research team led by H. S. Altszuller after a statistical analysis of more than 40,000 patents that sought to identify patterns of innovative solutions. In contrast to the trial-and-error method, TRIZ, thanks to its ability to bypass faulty concepts, allows for the optimal solution to be found in a more effective way. TRIZ's main feature is that it overcomes psychological inertia ("inertia's vector") resulting from habits, education and experience. Commonly considered an engineering method, TRIZ is becoming more and more popular among researchers in nearly all scientific fields, including representatives of the social sciences and economy.
Szacowanie wielkości krystalitów i udziału faz w austenitycznej stali nierdzewnej 1.4307 po walcowaniu za pomocą dyfrakcji promieni X
Authors: Sarnek Maciej
Published: December 2014

The material under investigation was a commercial austenitic stainless steel SS 1.4307 (EN) equivalent to AISI 304L. The samples of SS 1.4307 were rolled, achieving a 56, 60 and 62% reduction in thickness. The plastic deformation reduced austenite phase at the expense of the newly formed martensite phase. The volume fraction of austenite phase, crystallite size and lattice strain were calculated from X-ray line broadening. The X-ray diffraction measurements were carried out in a Philips X-Pert diffractometer using KαCu radiation.
Zmiany udziału defektów sieci krystalicznej dla austenitycznej stali nierdzewnej
Authors: Sarnek Maciej
Published: December 2014

Samples were plastically deformed using a hydraulic press, achieving a reduced thickness of from 2 to 16%. Isochronal cumulative annealing for 1 h at a temperature range from room temperature to 725°C was then performed. After each annealing, the positron measurement was performed using a Doppler broadening spectrometer with a coaxial high purity germanium detector. The 68Ge/ 68Ga positron source was used for Doppler broadening measurements. The aim of the presented investigations is to study the annealing behaviour of deformed stainless steel 1.4301 (EN) in terms of defects detected by positron annihilation methods while closely observing the influence of the reverse transformation of deformation induced martensite on the obtained dependencies.
Adaptation of Relationship Assessment Scale to Turkish Culture: Study of Validity and Reliability
Authors: Çelik Eyüp
Published: December 2014

The aim of this research is to examine validity and reliability of Turkish version of Relationship Assessment Scale. The results of exploratory factor analysis demonstrated that seven items loaded on single-factors and that the factor structure was harmonized with the factor structure of the original scale. Confirmatory factor analysis, chi-square (x²=52.87, sd=13, p=0.00) significantly, while indices of fit RMSEA=.097, GFI=.98, AGFI=.97, CFI=.96, IFI=.96, NFI=.95 and RFI=.92 was found. The scale’s internal consistency is .87 and Split-half is .82 and result of t-test was significant. The scale’s corrected item-total correlations is ranked from .52 to .74. Results show that the scale is a valid and reliable instrument.
An assessment of boiling as a method of household water treatment in South India
Authors: Juran Luke , MacDonald Morgan C.
Published: December 2014

This article scrutinizes the boiling of water in Tamil Nadu and Puducherry, India. Boiling, as it is commonly practiced, improves water quality, but its full potential is not being realized. Thus, the objective is to refine the method in practice, promote acceptability, and foster the scalability of boiling and household water treatment (HWT) writ large. The study is based on bacteriological samples from 300 households and 80 public standposts, 14 focus group discussions (FGDs), and 74 household interviews. Collectively, the data fashion both an empirical and ethnographic understanding of boiling. The rate and efficacy of boiling, barriers to and caveats of its adoption, and recommendations for augmenting its practice are detailed. While boiling is scientifically proven to eliminate bacteria, data demonstrate that pragmatics inhibit their total destruction. Furthermore, data and the literature indicate that a range of cultural, economic, and ancillary health factors challenge the uptake of boiling. Fieldwork and resultant knowledge arrive at strategies for overcoming these impediments. The article concludes with recommendations for selecting, introducing, and scaling up HWT mechanisms. A place-based approach that can be sustained over the long-term is espoused, and prolonged exposure by the interveners coupled with meaningful participation of the target population is essential.
Fluoride adsorption properties of three modified forms of activated alumina in drinking water
Authors: Duan Ying , Wang Chenchen , Li Xuede , Xu Wei
Published: December 2014

The study describes the removal of fluoride from drinking water using activated alumina (AA). AA was modified with H2SO4, FeCl3 and a combination of the two to enhance fluoride adsorption. The AA adsorbents were characterized using Brunauer–Emmett–Teller surface area analysis and X-ray fluorescence. The maximum adsorption capacity of H2SO4- and FeCl3-modified AA adsorbents was 4.98 mg/g, which is 3.4 times higher compared with that of normal AA. The results showed that the surface area of AA increased when modified with H2SO4. AA modified with FeCl3 enhanced fluoride adsorption ability through ion-exchange between chlorine ions and fluoride ions. The fluoride adsorption properties of AA modified with both H2SO4 and FeCl3 were consistent with the Langmuir model. The fluoride adsorption kinetics of the adsorbents were well described by the pseudo-second-order kinetic model.
Removal of the cyanotoxin anatoxin-a by drinking water treatment processes: a review
Authors: Vlad Silvia , Anderson William B. , Peldszus Sigrid , Huck Peter M.
Published: December 2014

Anatoxin-a (ANTX-a) is a potent alkaloid neurotoxin, produced by several species of cyanobacteria and detected throughout the world. The presence of cyanotoxins, including ANTX-a, in drinking water sources is a potential risk to public health. This article presents a thorough examination of the cumulative body of research on the use of drinking water treatment technologies for extracellular ANTX-a removal, focusing on providing an analysis of the specific operating parameters required for effective treatment and on compiling a series of best-practice recommendations for owners and operators of systems impacted by this cyanotoxin. Of the oxidants used in drinking water treatment, chlorine-based processes (chlorine, chloramines and chlorine dioxide) have been shown to be ineffective for ANTX-a treatment, while ozone, advanced oxidation processes and permanganate can be successful. High-pressure membrane filtration (nanofiltration and reverse osmosis) is likely effective, while adsorption and biofiltration may be effective but further investigation into the implementation of these processes is necessary. Given the lack of full-scale verification, a multiple-barrier approach is recommended, employing a combination of chemical and non-chemical processes.
Development of a novel bag-mediated filtration system for environmental recovery of poliovirus
Authors: Fagnant Christine Susan , Beck Nicola Koren , Yang Ming-Fong , Barnes Kilala Sayisha , Boyle David S. , Meschke John Scott
Published: December 2014

Poliovirus (PV) is on the verge of global eradication. Due to asymptomatic shedding, eradication certification requires environmental and clinical surveillance. Current environmental surveillance methods involve collection and processing of 400-mL to 1-L grab samples by a two-phase separation method, where sample volume limits detection sensitivity. Filtration of larger sample volumes facilitates increased detection sensitivity. This study describes development of a pumpless in-field filtration system for poliovirus recovery from environmental waters. Recovery of PV types 1, 2, and 3 were compared for glass wool, ViroCap, and NanoCeram (PV1 only) filters. Seeded experiments were performed using 105 plaque forming units of PV inoculated into 10-L volumes of secondary effluent, surface water, or a 50:50 mixture of each at pH 7.0. Filter eluates were plated onto buffalo green monkey kidney cells for virus enumeration by plaque assay. Across all water types, recovery from glass wool filters for PV1, PV2, and PV3 averaged 17%, 28%, and 6%, respectively. Recovery from ViroCaps for PV1, PV2, and PV3 averaged 44%, 70%, and 81%, respectively. 10-L samples of moderate turbidity water were processed through ViroCap filters in less than 30 minutes using a pumpless, bag-mediated filtration system. Bag-mediated filtration offers a simple, compact, and efficient method for enhanced environmental PV surveillance.
Sensitivity of quantitative microbial risk assessments to assumptions about exposure to multiple consumption events per day
Authors: Van Abel N. , Blokker E. J. M. , Smeets P. W. M. H. , Meschke J. S. , Medema G. J.
Published: December 2014

Quantitative microbial risk assessments (QMRAs) of contaminated drinking water usually assume the daily intake volume is consumed once a day. However, individuals could consume water at multiple time points over 1 day, so the objective was to determine if the number of consumption events per day impacted the risk of infection from Campylobacter jejuni during short-term contamination events. A probabilistic hydraulic and risk model was used to evaluate the impact of multiple consumption events as compared to one consumption event on the health risk from the intake of contaminated tap water. The fraction of the population that experiences greater than 10−4 risk of infection per event at the median dose was 6.8% (5th–95th percentile: 6.5–7.2%) for one consumption event per day, 18.2% (5th–95th: 17.6–18.7%) for three consumption events per day, and 19.8% (5th–95th: 14.0–24.4%) when the number of consumption events varied around 3.49 events/day. While the daily intake volume remained consistent across scenarios, the results suggest that multiple consumption events per day increases the probability of infection during short-term, high level contamination events due to the increased coincidence of a consumption event during the contamination peak. Therefore, it will be important to accurately characterize this parameter in drinking water QMRAs.
Relationship between organic precursors and N-nitrosodimethylamine (NDMA) formation in tropical water sources
Authors: Qi Wang , Fang Yee Lim , Jiangyong Hu
Published: December 2014

The presence of organic compounds in water sources is one of the concerns in water treatment. They are potential precursors of disinfection byproducts (DBPs) and thus induce health problems in humans. Among the emerging DBPs, carcinogenic compound N-nitrosodimethylamine (NDMA) has been receiving attention during the last decade. This study examined the characteristics of organic components in various water sources and investigated their relationships with NDMA formation. Experiments were carried out on selected water samples from both natural water and wastewater. Results showed similar NDMA formation kinetics for both water sources. However, more contribution of NDMA precursors was found to be from the wastewater due to its higher organic nitrogen content. NDMA formation potential (NDMAFP) of secondary effluent ranged from 264 to 530 ng/L. A correlation study between organic compound characteristics and NDMAFP indicated that the majority of NDMA precursors came from dissolved organic nitrogen (DON) compound with small molecular weight (smaller than 500 Da), with correlation R2 = 0.898. Although secondary treatment removed more than 90% of NDMA precursors, the remaining precursors in secondary effluent would still pose a challenge for water quality.
Water used to moisten vegetables is a source of Escherichia coli and protozoan parasite contamination at markets in Hanoi, Vietnam
Authors: Tram Nguyen Thuy , Dalsgaard Anders
Published: December 2014

The study was done to assess the level of fecal (Escherichia coli) and protozoan parasite (Cryptosporidium spp. and Giardia spp.) contamination in water used by traders to moisten vegetables at markets in Hanoi, Vietnam. A total of 200 splashing water samples from markets located within eight districts were analyzed for E. coli and Cryptosporidium spp. and Giardia spp. (oo)cysts. Giardia cysts were found in 17 splashing water samples and Cryptosporidium oocysts in nine samples, with median values of 20 cysts ml−1 and 10 oocysts ml−1, respectively. E. coli was found with a median concentration of 636 cfu ml−1 and its occurrence was negatively correlated with the numbers of protozoan parasites. The splashing water was kept in buckets that were rarely cleaned and often used for handwashing. The finding of these pathogens in splashing water is likely to represent real food safety hazards.
Experience, training and confidence among small, non-community drinking water system operators in Ontario, Canada
Authors: Pons Wendy , McEwen Scott A. , Pintar Katarina , Jones-Bitton Andria , Young Ian , Papadopoulos Andrew
Published: December 2014

The water operator plays an important role in water safety; however, little published research exists that has examined this role. The purpose of this study was to develop a greater understanding of the experience, existing knowledge, confidence and future training needs of the small, non-community drinking water operator in Ontario in order to help guide future outreach and training opportunities. A cross-sectional telephone survey of 332 small, non-community drinking water operators in Ontario was conducted in July and August 2011. Survey questions pertained to respondents' experience as operators, formal training, perceived importance of water safety issues, confidence in handling water safety issues, and future training needs. Approximately 16% (54/330) of respondents had one year or less experience as a water operator, and 60% (199/332) reported that being a water operator was not a chosen profession. Only 37% (124/332) of operators reported completing operator training. Respondents reported a preference for online training courses or on-site training (compared with a classroom setting). Low training rates, inexperience, and in certain situations, low confidence, among many small water system operators highlight a need to provide continued support to the development of ongoing training opportunities in this population.
Minimum inhibitory concentration distribution in environmental Legionella spp. isolates
Authors: Sandalakis Vassilios , Chochlakis Dimosthenis , Goniotakis Ioannis , Tselentis Yannis , Psaroulaki Anna
Published: December 2014

In Greece standard tests are performed in the watering and cooling systems of hotels’ units either as part of the surveillance scheme or following human infection. The purpose of this study was to establish the minimum inhibitory concentration (MIC) distributions of environmental Legionella isolates for six antimicrobials commonly used for the treatment of Legionella infections, by MIC-test methodology. Water samples were collected from 2004 to 2011 from 124 hotels from the four prefectures of Crete (Greece). Sixty-eight (68) Legionella isolates, comprising L. pneumophila serogroups 1, 2, 3, 5, 6, 8, 12, 13, 15, L. anisa, L. rubrilucens, L. maceachernii, L. quinlivanii, L. oakridgensis, and L. taurinensis, were included in the study. MIC-tests were performed on buffered charcoal yeast extract with α-ketoglutarate, L-cysteine, and ferric pyrophosphate. The MICs were read after 2 days of incubation at 36 ± 1 °C at 2.5% CO2. A large distribution in MICs was recorded for each species and each antibiotic tested. Rifampicin proved to be the most potent antibiotic regardless of the Legionella spp.; tetracycline appeared to have the least activity on our environmental isolates. The MIC-test approach is an easy, although not so cost-effective, way to determine MICs in Legionella spp. These data should be kept in mind especially since these Legionella species may cause human disease.
Assessing point-of-use ultraviolet disinfection for safe water in urban developing communities
Authors: Barstow Christina K. , Dotson Aaron D. , Linden Karl G.
Published: December 2014

Residents of urban developing communities often have a tap in their home providing treated and sometimes filtered water but its microbial quality cannot be guaranteed. Point-of-use (POU) disinfection systems can provide safe drinking water to the millions who lack access to clean water in urban communities. While many POU systems exist, there are several concerns that can lead to low user acceptability, including low flow rate, taste and odor issues, high cost, recontamination, and ineffectiveness at treating common pathogens. An ultraviolet (UV) POU system was constructed utilizing developing community-appropriate materials and simple construction techniques based around an inexpensive low-wattage, low pressure UV bulb. The system was tested at the bench scale to characterize its hydrodynamic properties and microbial disinfection efficacy. Hydraulically the system most closely resembled a plug flow reactor with minor short-circuiting. The system was challenge tested and validated for a UV fluence of 50 mJ/cm2 and greater, over varying flow rates and UV transmittances, corresponding to a greater than 4 log reduction of most pathogenic bacteria, viruses, and protozoa of public health concern. This study presents the designed system and testing results to demonstrate the potential architecture of a low-cost, open-source UV system for further prototyping and field-testing.
Estimating microbial risk in treated wastewater for reuse: a case study in Lund, Sweden
Authors: Liu Shuang , Persson Kenneth M.
Published: December 2014

The potential microbial risk from using treated wastewater is a burning issue to be studied. In Sweden, only a small part of treated wastewater is reused directly, although water reuse could be beneficial. Disinfection is virtually never practised and no protective guidelines for water reuse are found in Sweden. Based on a 1 year monitoring programme of water quality, this paper estimates the microbial risk of Escherichia coli and rotavirus in treated wastewater for different applications of irrigation, landscape, industry, unban non-potable water. A Quantitative Microbial Risk Assessment model is used and the samples were collected from the pond system of Källby wastewater treatment plant in Lund, Sweden. The results are used to evaluate if the treated wastewater after tertiary treatment process combined with pond system can be reused for different applications from a microbial point of view. The risk assessment results show that the studied water is only suitable for agriculture irrigation, while additional treatment or disinfection are needed for other applications since the potential risks are higher than the value that can be accepted. The protective guidelines are discussed based on the process and results of risk assessment and suggestions for establishing a structure of guidelines in Sweden are presented.
Retinal Nerve Fiber Layer Alterations After Photocoagulation: A Prospective Spectral-Domain OCT Study
Authors: Eren Sıtkı , Ozturk Taylan , Yaman Aylin , Oner Hakan , A Osman Saatci
Published: December 2014

Purpose :

To evaluate the effect of panretinal photocoagulation (PRP) on retinal nerve fiber layer thickness (RNFLT) in treatment-naive patients with proliferative diabetic retinopathy (PDR).

Methods :

Fifty eight previously untreated eyes of 30 patients with PDR who underwent PRP treatment were enrolled prospectively. All patients had at least six months of follow-up. Detailed ophthalmologic examinations including macular thickness and RNFLT assessments with spectral-domain type optic coherence tomography were performed at baseline as well as the third and sixth posttreatment months. Initial RNFLT and macular thickness of laser administered patients were compared with two separate control groups that were consisted of either nondiabetic patients or diabetics without PDR.

Results :

The mean age of study patients was 52.4±7.1 years (Range, 32-66 years) and 16 of them (53.3%) were female. At the sixth post-PRP month, visual stabilization or improvement was achieved in 54 eyes (93.1%). No significant difference was demonstrated in initial RNFLT measurements between the study patients and two control groups (p=0.478). Mean RNFLT was measured as 108.5±17.5µm, 115.8±17.6µm, and 103.0±16.4µm at baseline, third and sixth months of the follow-up, respectively. Although RNFLT increase noted at the third post-laser month was statistically significant compared to its baseline values (p<0.001), there was a significant reduction in RNFLT at the sixth post-laser month compared to its baseline values (p<0.001).

Conclusion :

RNFLT increase in the third month of follow-up may be related to ensuing axonal edema. Significant RNLFT decrease at the sixth month of follow-up may be attributed to axonal loss secondary to the laser treatment.
Irish Physical Education Cooperating Teachers’ Experiences of Learning to Become a ‘Teacher of Teachers’
Authors: Young Ann-Marie , MacPhail Ann
Published: December 2014

This article presents case studies detailing the learning trajectories of two physical education (cooperating)
teachers as they strive to establish and maintain their identity as competent and confident supervisors to pre-service
teachers on school placement. The cooperating teachers who participated in the study share their experiences in
attempting to construct a professional identity within the school placement triad. Lave and Wenger’s (1991) theory of
situated learning and the concept of legitimate peripheral participation were employed to investigate each of the
cooperating teacher’s journeys in their attempt to shape their professional identity through participation in a variety of
professional learning communities. The data revealed that the cooperating teachers experienced various forms of
legitimate peripheral participation and, as a result, their learning trajectories and attempts to construct professional
identities were diverse. The cooperating teachers’ learning did not always follow a positive trajectory, often meeting
obstacles, resulting in the teachers experiencing both highs and lows during the supervision process.
Pre-Service Physical Education Teachers’ Discourses on Learning How to Become a Teacher: [Re]Constructing a Professional Identity Based on
Visual Evidence
Authors: A. da Cunha Mariana , Batista Paula , Graça Amândio
Published: December 2014

Identity has been used as an analytical tool to capture how teachers work, learn and develop professionally.
This paper takes chiefly Gee’s [1] discursive notion of identity to examine the discourses that pre-service physical
education teachers used about themselves and others in discussing their teaching practices in the context of their
practicum training in school. More specifically, this study aims to identify and characterize the situations of concern
[roles, individuals, groups, events, meanings] to the pre-service teachers when learning to be a physical education teacher
and when [re]constructing their professional identity through a dialogic relation between talk and images. Nine preservice
teachers from the Faculty of Sport, University of Porto participated in this study. Data were gathered using photo
elicitation interview technique: photographs and videos, produced by the participants, were used as prompts for discussion
in two focus group sessions [2, 3]. We adopted an inductive approach to thematic analysis based on the Grounded Theory
coding principles [4, 5], supplemented by a situational analysis [6] to map visual discourses and construct photo-essays
[7] upon them. The images portrayed the participants in situations of classroom practice, learning-to-teach resources,
social recognition and teachers’ mission. Their discourses upon those photographs and videos recognized the physical
education teacher as a type of teacher who: [i] cares for planning duties, carefully prepares their lesson and complies with
institutional roles, as planning and teaching; [ii] constantly searches for professional excellence and updates their
knowledge [e.g. transferring pedagogical strategies fromother contexts]; [iii] individually/collectively reflects upon their
practice, learns and shares knowledge with their colleagues, is in constant development, and builds their identity in
allegiance with others [e.g. class observations and mentoring meetings]; and [iv] extends their school practice beyond the
instruction tasks and has the power to project and exercise higher roles [e.g. extracurricular roles].
Engagement Partner Identification: A Theoretical Analysis
Authors: Carcello Joseph V. , Santore Rudy
Published: December 2014

SYNOPSIS

We examine the likely effects of a regulatory requirement for the engagement partner to be personally identified in the audit report. We develop a model in which the engagement partner determines the level of resources devoted to the audit and whether to report aggressively. As long as the partner does not personally suffer reputation damages arising from aggressive reporting, the partner makes decisions that are optimal from the firm's perspective. However, the identification of the partner misaligns the incentives between the partner and the firm. We find that audit report accuracy should increase because engagement partners will find it optimal to gather more evidence. However, engagement partners may report more conservatively than the firm would prefer, as a result of misaligned incentives between the partner and the firm. Interestingly, the effects of a partner identification requirement are predicted to be more pronounced for large firms than for small firms, possibly affecting audit market competition and concentration. Overall, a partner identification requirement is likely to decrease the welfare of partners and firms and will not necessarily be socially optimal.
Twitter-Based Dissemination of Corporate Disclosure and the Intervening Effects of Firms' Visibility: Evidence from Australian-Listed Companies
Authors: Prokofieva Maria
Published: December 2014

This paper investigates the effect of dissemination of corporate disclosure via Twitter. In particular, the study is focused on listed companies in Australia that employed Twitter as a secondary dissemination channel for corporate announcements in 2008–2013. Based on a sample of 3,516 announcements at the Australian Stock Exchange (ASX) related to 109 listed companies, the research employs the Investor Recognition Hypothesis to investigate the effect of Twitter activity on the information asymmetry proxied by abnormal spread (SpreadAbn). The findings show that there is a negative association between SpreadAbn and tweets posted by a firm during the announcement period. Further analysis shows that this association is stronger for firms less visible through business press or financial analyst coverage. The study concludes that while corporate announcements are publicly available through the ASX platform, dissemination of corporate announcements through Twitter allows companies to attract investors' attention and decrease information asymmetry.
Do Social Media Matter? Initial Empirical Evidence
Authors: Du Hui , Jiang Wei
Published: December 2014

This paper examines the association between firm performance and social media. Based on a sample of S&P 1500 firms, the study finds that firms with a social media presence are more highly valued by the market and have higher future financial performance. Further analysis indicates that the impact of social media on firm performance varies depending on the social media platform involved. Finally, using a restricted sample of Global 100 firms, the study finds some evidence that a higher level of social media engagement is associated with higher firm performance. Overall, these findings provide consistent evidence of the positive impact of social media technologies on firm performance.

Data Availability: All data are available from public sources.
Structural Characteristics of New Continuous Arch Bridges
Authors: Miyachi Kazuhiro , Nakamura Shunichi , Usui Masayuki
Published: December 2014

Three new types of continuous steel arch bridges are proposed and the structural characteristics are studied: the continuous arch bridge (model-A), the S-shaped arch bridge (model-B), and the double arch bridge (model-C). The continuous arch bridge has upward arch ribs. The S-shaped arch bridge has upward and downward arch robs. The double arch bridge has both upward and downward arch ribs. The arch ribs and the girders are all continuous on these bridges, which improves seismic resistance. It also eliminates expansion joints which improves drivability and reduces noises and vibrations. These three continuous arch bridges are studied in two stages. First, the member cross sections are determined for the dead and design live loads by the allowable stress method, and then the structural characteristics are studied. The S-shaped arch bridge has a larger vertical displacement than the other bridges. The vertical displacement and bending moment of the arch ribs and the girder of the double arch bridge are smaller than the others. Second, elastic plastic large deformation analysis is conducted to find the ultimate strength of the new arch bridges. It is found that the lateral buckling is critical in all the models. The initial imperfection is also considered by inclining the arch planes. This non-linear analysis shows that the proposed bridges have sufficient ultimate strength. Finally, the construction cost of these new arch bridges is estimated, finding that model-C requires more steel by 15% than model-A and model-B. In conclusion, the proposed new bridges are found to be feasible.
Evaluation of Secondary Stress at Main Cable in Suspension Bridge
Authors: Lee Minjae , Choi Jinhyuk , Yoon Jahgeol , Kim Ho-Kyung
Published: December 2014

The evaluation method of the secondary stress of the main cable in suspension bridge is suggested briefly. The secondary stress of the main cable in Yi Sun-sin Bridge is estimated by the suggested method considering the actual residual tension of the wrapping wires measured in construction site. The secondary stress considering both the construction stage and service stage exceeds 10% of the tensile strength of wires in the main cable.
Balance of nature and engineering requirements on existing arch bridges
Authors: Mandić Ivanković Ana , Gleđ Niko , Franetović Marin
Published: December 2014

In order to sustain the equilibrium between the nature and requirements on structures based on contemporary standards, research on development of assessment procedures for existing arch bridges exposed to wind load and located in seismic active areas is developing through last few years in Croatia as a part of an extensive project to develop their appropriate maintenance strategy. In this paper an overview of assessment results for Adriatic arch bridges with spans ranging from 200 m to almost 400 m will be presented. More detailed assessment of the Krk Bridge spanning 244 m and exposed to severe wind load will be presented.
Multiscale Analysis of the Arch Feet Zone for CFST Arch Bridges with Steel Truss and Tie-Beams
Authors: Zhou Meng , Ning Xiao-Xv , Nie Jian-Guo , Fan Jian-Sheng
Published: December 2014

As the key sub-structure of this kind of bridges, the arch feet play an important role securing the safety and good serviceability of the entire bridge, and consequently the study on the mechanical behavior of the arch feet is essential for both the analysis and design of the whole bridge. However, the traditional local-elaborate modelling method for the study is enslaved to the strong dependence of the Saint-Venant Principle and significant influence of the Fuzzy Region, leading to unreliable analysis results. To solve this problem, the multiscale modelling method is introduced in this paper, employing the flexible boundary conditions (BCs) for the simulation of the complex BCs of the arch feet. A multiscale model of the arch feet is then established according to the prototype of an actual CFST arch bridge project, Dalian 1# Bridge in Dalian, China. Simultaneously, a local- elaborate model is built for comparison, and a global-elaborate model, which denotes an elaborate model of the entire bridge using shell and solid elements, is built for further validation. Intensive comparison study of the three finite element models shows that the result of the multiscale model is reliable without the influence of the Fuzzy Region. It is also demonstrated that the multiscale modeling method is accurate, efficient and well applicable for the study on the arch feet of CFST arch bridges. It is concluded that the multiscale modelling method may offer a more reasonable and reliable approach for the analysis of the arch feet zone, persisting high efficiency and well applicability
Transfer zone cracking research of a new type of prestressed floor slab
Authors: Rueda-Contreras Jorge , González-Valle Enrique , Díaz-Heredia Elena , Ley-Urzaiz Jorge
Published: December 2014

This paper discusses a new typology of precast concrete slab designed for one-way floors. The members, without transverse reinforcement, are prestressed with pretensioned wires or strands. Due of the unusual cross-section geometry of these slabs, and the closely related spread of the prestressing forces, the design is highly susceptible to appear cracking at prestress release. This cracking is related to the existence of high tensile stresses. This explains the documented existence of brittle failure in these members during building construction. Different analytical models have been used to calculate the end zone tensile stress, and the results are disparate. Due to these circumstances, authors are currently performing a research at Technical University of Madrid, whose aim is to find an analytical model to resolve the aforementioned problems.
Design Expressions for the Effective Width of Composite Steel-Concrete Members
Authors: Gara Fabrizio , Ranzi Gianluca , Leoni Graziano
Published: December 2014

This paper presents a new approach for the evaluation of the effective width for the analysis of composite steel-concrete members. The proposed method is based on the use of simple expressions which enable the calculation of the effective width of the slab accounting for shear-lag effects. Its particularity relies on its ability to utilize the results of a global analysis carried out specifying the real width of the slab along the whole bridge length and to port-process these by means of a cross- sectional analysis using simple design equations to define the geometry of the concrete slab. The expressions for the effective widths have been derived for different loading conditions including constant uniformly distributed loads, envelopes of transverse actions due to traffic loads, support settlements, thermal effects and shrinkage. Several applications are then presented to outline the ability of the proposed method to accurately predict the stress state in the concrete slab while accounting for shear-lag effects. These results are also compared against those obtained based on available design guidelines and calculated by means of the finite element method using line and shell elements.
Numerical and experimental evaluation of concrete cracking in timber concrete composite bridge beams
Authors: Schanack Frank , Ramos Óscar Ramón , Reyes Juan Patricio , Alvarado Andrés
Published: December 2014

TCC bridges are a more durable alternative to the very high number of conventional timber bridges en Chile´s road network. In a research project, numerical analyses and laboratory tests were conducted in order to obtain the influence of concrete cracking in TCC beams. The results from the FEM simulations and from the shear tests indicate that the influence of the concrete cracking is not limited to a stiffness reduction of the concrete slab, but it the stiffness of the shear connectors is reduced, too. No other parameter was found to significantly improve the correlation between simulations and real tests. Laboratory tests validate that small concrete cracks can cause significant connector stiffness reductions. Good correlations on the safe side between numeric simulation and test results is obtained, if the connectors’ slip modulus is reduced by 60%, in addition to the theoretic concrete cracking.
Vibration Behaviour and Seismic Performance of a Steel Cable-Stayed Bridge with Low-Rise Pylons
Authors: An Tongxiang , Kiyomiya Osamu , Hoang Vu
Published: December 2014

In this study, the vibration behaviour and seismic performance of a cable-stayed bridge with a centre span of 575 m in length and pylons of 95.5 m in height were verified. The height of the pylon and the connection condition between the stiffness girder and pylons were assumed to be parameters. As a result, the parameters studied in this work greatly affected the vibration behaviour and seismic performance of the bridge.
Exploring the Effect of Expansion Joints Spacing in Concrete Multistory Buildings
Authors: Nafie Amr M.
Published: December 2014

Temperature and shrinkage effects may cause cracks and additional stresses in the structural components of concrete buildings. In order to limit the undesirable effects of temperature and shrinkage, it is recommended by many building codes to use expansion joints in long buildings. In this study the effect of temperature and shrinkage on multistory buildings was explored. 3D finite element models were constructed for multistory buildings with different lengths and heights, and analyzed using various temperature loads. A factor termed in this study the temperature design ratio was developed to evaluate the maximum spacing between expansion joints that can be used with out including temperature effects in the analysis. This factor was calculated by comparing the design obtained using temperature and vertical loads to that obtained using vertical loads alone. Different factors affecting the response of the structure to temperature strains were also studied.
Strength and Plastic Deformation Capacity of H-shaped Beam-Columns
Authors: Hasegawa Ryuta , Ikarashi Kikuo
Published: December 2014

One of the authors has proposedWF, the new limitation of plate slenderness ratio, which considers stress distribution within H-shaped beams and coupled instability of web and flanges and has succeeded in evaluation for ultimate strength and plastic deformation capacity of H-shaped beams withWF. This study is intended to examine whetherWFcan also be adapted for evaluating the performance of H-shaped beam-columns and to develop evaluation method of it. As a result, this study found that ultimate strength and plastic deformation capacity of H-shaped beam-columns can be evaluated with equation (2) and equation (4) , (5) , respectively.
Behaviour of Webs of Box-Girder Span during Launching
Authors: Timofeev Michael
Published: December 2014

Observation data of web deformations of the box-section continuous span of River Kama Bridge in Perm, Russia, when in use of longitudinal launching are presented. The purpose of this work is analysis of influence the span assemblage technology on changing of primordial web cambers depending on web thickness.
Genetic analysis of a Bison bison herd derived from the Yellowstone National Park population
Authors: Herman Julia A. , Piaggio Antoinette J. , Halbert Natalie D. , Rhyan Jack C. , Salman M. D.
Published: December 2014

The objective of this study is to inventory the current genetic diversity of the bison quarantine feasibility study (BQFS) herd originating from Yellowstone National Park (YNP) using previously described microsatellite, mitochondrial and nuclear DNA markers with the aim to determine the degree, if any, of cattle DNA introgression in this herd. This work can provide an important tool in monitoring and managing bison genetic diversity as brucellosis‐free reintroduced herds are re‐established throughout the US for conservation purposes. The BQFS composed of 89 Bison bison from YNP that were quarantined and tested to qualify as free of brucellosis in 2006–2007. Understanding genetic diversity of the herd is important to determine if any genetic characteristics such as cattle DNA introgression or low genetic diversity may threaten the herd's protected status. We evaluated genetic diversity at 42 microsatellite loci representing each of the nuclear chromosomes in the bison genome. We found no detectable evidence of cattle DNA introgression in this herd through nuclear markers and mitochondrial DNA analysis. Parentage analysis of the BQFS herd indicated that the majority of mature adults were actively breeding and contributing offspring. Genetic diversity levels in the quarantined herd were high and comparable to the YNP parent herd, suggesting a low risk of genetic loss in the near future. Based on these findings, the genetic diversity currently available within the BQFS herd will provide a strong foundation for bison reintroduced herds and for the preservation of the species.
Infant Feeding Practices Among the Mothers of Selected Different Socio-economic Groups in Dhaka City
Authors: Sumon MYA , Haque MM , Islam K
Published: December 2014

This study was conducted to understand the infant (0-12 month) feeding practices among different classes' mothers in Dhaka city. The study was carried out among the 183 mother-infant pair of the upper, middle and lower socio-economic classes in Dhaka city and purposive sampling method was applied. The study was conducted at following areas in Dhaka city which were selected purposively. The mean age of upper class, middle class and lower class were 35±4, 25±3 and 21±7 in years. Regarding first feeding it was observed that upper (75%), middle (85%) and lower class (48%) first gave colostrum. It also observed that 18% of upper class mother first gave powder milk, while in case of middle class it was 5%. In lower class preference of giving honey and sugar water were 21% and 12% respectively. The starting time of breast feeding indicated that in upper classes (74%) breast feeding initiated within one hour, while in middle (75%) and lower classes (84%) it was given within 12 hours. It was highlighted that 44% upper and 36% lower class mothers started complementary feeding at 3 month of the baby respectively, while in middle class 61% mother started complementary foods at 5 month of their baby. In case of duration of breast feeding practices, middle and lower classes breast-feed continued longer time than upper class. Majorities of the upper class prefered egg, soup, fruit juice while middle class liked meat-fish, egg, khichuri, fruits. On complementary feeding the lower class choiced mainly rice-potato, dal, khichuri or vegetables. The study result should not be generalise and need further large scale research. DOI: http://dx.doi.org/10.3329/akmmcj.v5i2.21124 Anwer Khan Modern Medical College Journal Vol. 5, No. 2: July 2014, Pages 5-8
Maternal Risk Factors Associated With Autistic Children
Authors: Riya S , Begum M , Begum N , Majid F , Jahan S , Rahman A
Published: December 2014

The present study has been carried out to find out the distribution of prenatal, perinatal and postnatal factors associated with autistic children. The study was conducted on 270 autistic children with age ranges of 3-10 years attending special schools in Dhaka city exclusively for autistic children during July ,2001 to July ,2012 .Mean age of mother was 31.78 SD± 5.94 years .Socio demographic characteristics showed 84% housewives, 37% educated up to masters level. Mean family monthly income was Tk.24,596 SD±11,464.Antenatal factors showed 42.2% mothers anemic,44.4% had H/O pre eclampsia,40% threatened abortion, 38.1% had gestational diabetes. Perinatal factors showed obstructed labor to be 64.4%.Post natal factors showed birth asphyxia to be 47.0% and neonatal jaundice 72.6% . The study showed a higher maternal age is significantly associated with autism.(p=0.007, RR=1.18,95% CI, 0.87- 1.60) and birth asphyxia is strongly associated with autism (p=0.001,OR=8.86 , 95% CI, 1.91-41.04) .The increasing prevalence of ASD`s indicates that it is multifactorial in which genetic, prenatal, social, developmental, nutritional and environmental factors play major roles. DOI: http://dx.doi.org/10.3329/akmmcj.v5i2.21126 Anwer Khan Modern Medical College Journal Vol. 5, No. 2: July 2014, Pages 14-17