bluuebunny/crossref_metadata_2025 huggingface dataset:
The fouling characterization and control in the high concentration PAC membrane bioreactor HCPAC-MBR
Authors: Seo G.T. , Jang S.W. , Lee S.H. , Yoon C.H.
Published: May 2018

This study focuses on the experimental investigation to identify the effect of PAC at high concentrations on the fouling of membranes. A pilot-scale experimental apparatus was installed at a water treatment plant located downstream of Nakdong river basin, Korea. Effluent of rapid sand filter was used as influent of the system, which consists of PAC bio-reactor, submerged membrane module (hollow fiber with pore size 0.1 μm) and air supply facility. PAC was dosed at 40 g/L initially and it was not replaced during the operation period. Suction type filtration was carried out at intervals of 12 min. suction and 3 min. idling. At the initial flux 0.36 m/d, the system could be operated stably for around 90 days at target trans-membrane pressure (TMP) of 40 kPa. Among total resistance of membrane filtration, cake and gel layer resistance, Rc+Rg, was the dominant fraction (more than 90% of the total) to increase the filtration pressure, which means that the filtration resistance could be controlled by the PAC cake layer and then irreversible membrane fouling could be prevented. Three minutes air backwashing every 3 days could extend the operation period to 127 days. Organics were analyzed in terms of molecular weight structure. The influent of the system consists of 15.0% and 74.4% of hydrophobic and hydrophilic natural organic matter (NOM), respectively. Hydrophobic and hydrophilic (electrostatic) interaction was the main factor on fouling of the membrane in the reactor. Hydrophobic fraction decreased slightly in the effluent, which means hydrophobic NOM removal in the reactor by adsorption. Organics accumulated in the membrane were extracted for analysis after a certain period of operation. The fraction of hydrophobic and hydrophilic organics was 41.4% and 38.9%, respectively. On the basis of the experimental results, the hydrophobic organics were the major materials causing the fouling of the membrane, which should be changed to other types of material.
The relationship between critical flux and fibre movement induced by bubbling in a submerged hollow fibre system
Authors: Wicaksana F. , Fan A.G. , Chen V.
Published: May 2018

Bubbling has been used to enhance various processes. In this paper we deal with the effect of bubbling on submerged hollow fibre membranes, where bubbling is applied to prevent severe membrane fouling. Previous work with submerged hollow fibres has observed that significant fibre movement can be induced by bubbling and that there is a qualitative relationship between fibre movement and filtration performance. Therefore, the aim of the present research has been to analyse the link between bubbling, fibre movement and critical flux, identified as the flux at which the transmembrane pressure (TMP) starts to rise. Tests were performed on vertical isolated fibres with a model feed of yeast suspension. The fibres were subject to steady bubbling from below. The parameters of interest were the fibre characteristics, such as tightness, diameter and length, as well as feed concentration. The results confirmed that the critical fluxes are affected by the fibre characteristics and feed concentration. Higher critical flux values can be achieved by using loose fibres, smaller diameters and longer fibres. The enhancement is partially linked to fibre movement and this is confirmed by improved performance when fibres are subject to mechanical movement in the absence of bubbling.
Influence of module configuration and hydrodynamics in water clarification by immersed membrane systems
Authors: Sridang P. Choksuchart , Heran M. , Grasmick A.
Published: May 2018

Different immersed membrane systems were compared according to the module configuration. Filtering concentrated aqueous suspensions under constant permeate flux, the hydraulic performances of the systems were evaluated and compared through parameters such as critical permeate flux notion and trans-membrane pressure variation rates. Operational variables were membrane size and module fibre density, aeration inside or outside the fibre network, suspension concentration and physico-chemical conditioning. When using hollow fibres including a possible air injection inside the fibre network, results pointed out the positive role of the aeration on the fouling control. But too high a fibre density did not allow an optimal control when the aqueous suspension was very concentrated. On the other hand, when working with capillary membranes showing sufficient space between fibres, the major parameters were the transversal suspension flow circulation through the fibre network and the FeCl3 conditioning of the suspension. Experimental results show a possible working at a 0.07 m3.m2.h1 permeate flow rate under low TMP evolutions, 0.02 Pa/s, even if the filtration was operated under high concentrated suspension, 5 kgSS/m3.
Influence of floc structure on membrane permeability in the coagulation-MF process
Authors: Cho M.-H. , Lee C.-H. , Lee S.
Published: May 2018

The relation between floc structure and membrane permeability was studied in a coagulation-MF hybrid process. The floc structure changed with operating parameters in the coagulation process and was quantified with fractal dimension (dF). The concentration ratio between suspended colloids and injected coagulant had an essential effect on dF of coagulated flocs. Larger flocs with low fractal dimension were produced for ALT (aluminum ion concentration dosed/suspended particle concentration) between 0.4 and 0.8. Flocs maintained stable characteristics at the coagulation period of over 20 minutes.

Membrane permeability was improved with coagulated flocs of lower fractal dimension, which tend to have higher porosity and aggregate relatively loosely. These more porous flocs reduce specific resistance of coagulated flocs. The relation between membrane filterability and fractal dimension of flocs was explored in a submerged MF hybrid system as well as in a batch unstirred cell filtration.
Modeling the influence of temperature on degree of concentration polarization in reverse osmosis systems
Authors: Agashichev S.P.
Published: May 2018

A model describing the influence of temperature on degree of concentration polarization is proposed. The model is based on the following assumptions: (1) membrane morphology is temperature-independent; (2) transport characteristics of membrane are invariant with coordinate; (3) specific water permeability of the membrane is based on exponential dependence of viscosity vs. temperature; (4) temperature-dependence of membrane rejection is assumed to be linear. Proposed models permit quantitative correlations of longitudinal mass flow and degree of concentration polarization at different operating temperatures. It enables analysis of the influence of temperature, mass flow, bulk concentration, axial velocity, channel geometry, physical properties and membrane rejection on longitudinal distribution of concentration polarization degree. The submitted model does not contain digital integration and can be segmented into optimization algorithms.
Rejection of trace organic compounds by high-pressure membranes
Authors: Kim T.-U. , Amy G. , Drewes J.E.
Published: May 2018

High-pressure membranes, encompassing reverse osmosis (RO), nanofiltration (NF), and low-pressure RO, may provide an effective treatment barrier for trace organic compounds including disinfection by-products (DBPs), pesticides, solvents, endocrine disrupting compounds (EDCs) and pharmaceutically active compounds (PhACs). The objective is to develop a mechanistic understanding of the rejection of trace organic compounds by high-pressure membranes, based on an integrated framework of compound properties, membrane properties, and operational conditions. Eight trace organic compounds, four DBPs and four chlorinated (halogenated) solvents, are being emphasized during an initial study, based on considerations of compound properties, occurrence, and health effects (regulations). Four polyamide FilmTec membranes; three reverse osmosis/RO (BW-400, LE-440, XLE-440) and one nanofiltration/NF (NF-90); are being characterized according to pure water permeability (PWP), molecular weight cutoff (MWCO), hydrophobicity (contact angle), and surface charge (zeta potential). It is noteworthy that rejections of compounds of intermediate hydrophobicity by the candidate membranes were observed to be less than salt rejections reported for these membranes, suggesting that transport of these solutes through these membranes is facilitated by solute-membrane interactions. We are continuing with diffusion cell measurements to describe solute-membrane interactions by estimation of diffusion coefficients through membranes pores, either hindered or facilitated.
Processes of particle deposition in membrane operation and fabrication
Authors: Wiesner M.R. , Tarabara V. , Cortalezzi M.
Published: May 2018

The processes that control particle deposition on surfaces that are of interest in understanding operational aspects of membrane filtration, also hold significance in controlling the morphology of particle deposits as intermediate steps in membrane fabrication. This paper summarizes processes controlling particle deposit morphology. The implications of these processes for understanding membrane fouling by particles and in fabricating membranes are then considered.
Incorporating membrane gas diffusion into a membrane bioreactor for hydrogenotrophic denitrification of groundwater
Authors: Mo H. , Oleszkiewicz J.A. , Cicek N. , Rezania B.
Published: May 2018

A hydrogenotrophic denitrification system, comprising a suspended growth membrane bioreactor (MBR) with membrane hydrogen gas diffusion, was developed to remove nitrate from groundwater. A hollow fiber gas permeable membrane module was designed for hydrogen delivery and a commercially available hollow fiber membrane module was used for solid/liquid separation. The MBR was operated at an SRT of 20 days and at room temperature. Four nitrate loading rates of 24, 48, 96 and 192 NO3−-N mg l−1 d−1 were applied to the system. As the nitrate loading was raised, pH increased due to increased denitrification and release of OH− ions. The oxidation reduction potential (ORP) remained fairly stable when full denitrification was achieved, but increased when nitrate loading rates reached 192 NO3−-N mg l−1 d−1 and residual nitrate was present in the reactor. Nitrate removal was complete (100%) in the first three nitrate loadings and 72% in the system with 192 NO3−-N mg l−1 d−1. Nitrate utilization rates of 30.6, 23.4, and 37.7 g NO3−-N m−3 d−1 were achieved in the first three loadings. Average effluent dissolved organic carbon (DOC) concentration of approximately 8 mg l−1 was observed in all four nitrate loading regimes, possibly owing to the generation and release of soluble microbial bi-products (SMP).
Nutrients removal in MBRs for municipal wastewater treatment
Authors: Kraume M. , Bracklow U. , Vocks M. , Drews A.
Published: May 2018

Owing to increasingly stringent effluent quality requirements, intensifications of the conventional activated sludge process (ASP) are required. Due to high biomass concentrations employed, higher metabolic rates and better nutrient removal are possible in membrane bioreactors (MBRs). Decoupling of hydraulic and solids residence times offers additional possibilities for process design and optimisation. Recently, unconventional concepts like post-denitrification and enhanced biological phosphorus removal in MBRs have emerged. The objective of this paper is to present current knowledge on nutrients removal in MBRs and trends in process optimisation in comparison with conventional ASP.
Anaerobic digestion: a new model for plant-wide wastewater treatment process modelling
Authors: Copp J.B. , Belia E. , Snowling S. , Schraa O.
Published: May 2018

This paper describes a new anaerobic digestion model for wastewater treatment systems (MantisAD). The model has been developed specifically for plant-wide wastewater treatment modelling. That is, rather than modelling nitrogen as a series of fractions of other carbonaceous state variables, this new model includes six dedicated nitrogen state variables. This structure makes this new anaerobic model easier to incorporate into plant-wide models by simplifying the aerobic/anaerobic model interfaces. The model is complete and initial success with the model has been achieved. A comprehensive description of the model including a Petersen Matrix representation of the model is included as is a case study in which the model is applied to full-scale anaerobic digesters.
Performance comparison of a continuous-flow stirred-tank reactor and an anaerobic sequencing batch reactor for fermentative hydrogen production depending on substrate concentration
Authors: Kim S.-H. , Han S.-K. , Shin H.-S.
Published: May 2018

This study was conducted to compare the performance of a continuous-flow stirred-tank reactor (CSTR) and an anaerobic sequencing batch reactor (ASBR) for fermentative hydrogen production at various substrate concentrations. Heat-treated anaerobic sludge was utilized as an inoculum, and hydraulic retention time (HRT) for each reactor was maintained at 12h. At the influent sucrose concentration of 5g COD/L, start-up was not successful in both reactors. The CSTR, which was started-up at 10g COD/L, showed stable hydrogen production at the influent sucrose concentrations of 10–60g COD/L during 203 days. Hydrogen production was dependent on substrate concentration, resulting in the highest performance at 30g COD/L. At the lower substrate concentration, the hydrogen yield (based on hexose consumed) decreased with biomass reduction and changes in fermentation products. At the higher substrate concentration, substrate inhibition on biomass growth caused the decrease of carbohydrate degradation and hydrogen yield (based on hexose added). The ASBR showed higher biomass concentration and carbohydrate degradation efficiency than the CSTR, but hydrogen production in the ASBR was less effective than that in the CSTR at all the substrate concentrations.
Evaluation of wastewater characterization methods
Authors: Choi E.-H. , Klapwijk B. , Mels A. , Brouwer H.
Published: May 2018

Wastewater contains various organic components with different physical and biochemical characteristics. ASM No. 1 distinguishes two categories of biodegradable organic matter in wastewater, rapidly and slowly biodegradable. In general there are two methods for wastewater characterization: based on filtration in combination with a long-term BOD test or based on a respirogram. By comparing both approaches, we showed that in wastewater three categories of organic compounds with different biodegradation rates can be distinguished. These categories are referred to as readily biodegradable, rapidly hydrolysable and slowly hydrolysable organic matter. The total biodegradable COD can be found from a long-term BOD-test combined with a curve-fit and the readily biodegradable and rapidly hydrolysable from a respirogram. The slowly hydrolysable is the difference between total biodegradable COD and the sum of readily biodegradable and rapidly hydrolysable COD. Simulation with characterization based on filtration for a pre-anoxic reactor with a certain N-removal compared with the N-removal of the same plant with wastewater according to the modified characterization shows different results of each wastewater, especially with regard to the effluent nitrate concentration.
Effects of surfactants originating from reuse of greywater on capillary rise in the soil
Authors: Shafran A.W. , Gross A. , Ronen Z. , Weisbrod N. , Adar E.
Published: May 2018

Greywater is all domestic wastewater excluding toilet effluents. Detergents contain surfactants, which account for the highest concentration of organic chemicals in average domestic wastewater. Accumulation of surfactants in greywater-irrigated soils was determined in three household gardens. The effect of surfactants on capillary rise in loess and sand was then tested in the range of concentrations found in the garden soils. The capillary rise of freshwater in sieved oven-dried soil mixed with different concentrations of laundry detergent solution (10% w/w moisture content) was determined. In a second setup, the soil was mixed with freshwater and the rising solution contained different concentrations of detergent solution. The introduction of laundry solution to the soils caused a significant decrease in the capillary rise over the range of concentrations that is found in greywater-irrigated soils. The effect was more noticeable in the sand than in the loess. Interestingly, in the second setup, the capillary rise of the laundry solutions in the sand was almost similar to that of freshwater, whereas in the loess the capillary rise was significantly reduced. It is suggested that accumulation of surfactants in the soil might form water repellent soils that have a significant effect on agricultural productivity and environmental sustainability.
Improvement of the thickening and dewatering characteristics of activated sludge by electroflotation (EF)
Authors: Choi Y.G. , Kim H.S. , Park Y.H. , Jeong S.H. , Son D.H. , Oh Y.K. , Yeom I.T.
Published: May 2018

The performances of electroflotation (EF) on the thickening of activated sludge were investigated using laboratory scale batch flotation reactors. Four activated sludges including bulking sludges were tested. After 30minutes of EF operation, 57–84% of sludge volume reduction could be achieved by EF, while only about 1.5–14% could be obtained by gravity thickening for the same period. After thickening the effluent water quality in terms of TCOD, SS, and turbidity was improved by EF operation for all sludge samples. In addition, the EF thickened sludge showed much better dewaterability both in SRF and cake solid content. It is induced that the air bubbles entrapped in the thickened sludge play a key role in the observed dewaterbility improvement.
Integrated biological (anaerobic–aerobic) and physico-chemical treatment of baker's yeast wastewater
Authors: Kalyuzhnyi S. , Gladchenko M. , Starostina E. , Shcherbakov S. , Versprille B.
Published: May 2018

The UASB reactor (35°C) was quite efficient for removal of bulk COD (52–74%) from simulated (on the basis of cultivation medium from the first separation process) general effluent of baker's yeast production (the average organic loading rates varied from 8.1 to 16g COD/l/d). The aerobic-anoxic biofilter (19–23°C) can be used for removal of remaining BOD and ammonia from anaerobic effluents; however, it suffered from COD-deficiency to fulfil denitrification requirements. To balance COD/N ratio, some bypass (∼10%) of anaerobically untreated general effluent should be added to the biofilter feed. The application of iron (III)-, aluminium- or calcium-induced coagulation for post-treatment of aerobic-anoxic effluents can fulfil the limits for discharge to sewerage (even for colour mainly exerted by hardly biodegradable melanoidins), however, the required amounts of coagulants were relatively high.
Characterization of sludge structure and activity in submerged membrane bioreactor
Authors: Spérandio M. , Masse A. , Espinosa-Bouchot M.C. , Cabassud C.
Published: May 2018

Sludge characteristics of a submerged membrane bioreactor (MBR) and an activated sludge process (AS) were compared, during a first phase at the same operating conditions (low MLSS and conventional SRT) and in a second phase with a high sludge retention time (SRT) in the membrane bioreactor. During the first phase, a bimodal flocs size distribution was observed in the MBR with simultaneously a macro-flocs population (240μm) bigger than the flocs of activated sludge due to the absence of recirculating pump, and also more microflocs (1 to 15μm) and free suspended cells retained by the membrane. It is shown that the membrane leads to an accumulation of proteins and polysaccharides in the sludge supernatant which is probably responsible for the high fouling propensity of the sludge during the starting period of MBR. These compounds are partially degraded after 50 to 60 days of operation. In the first phase respirometric experiments didn't demonstrate a significant difference in the maximal removal rates of either MBR or AS biomass (with excess substrate), except in the dynamic period during which the membrane retention gave an advantage by increasing the biomass activity. On the other hand, the respirometry shows that the half saturation constant for nitrification was significantly higher in the MBR process, suggesting higher substrate transfer limitation. During the last phase, it is shown that an increase of SRT from 9 to 106 days leads to a diminution of average macro-flocs size in the MBR from about 240 to 70μm. With the SRT increase, modification in the organic compounds is also observed (proteins, polysaccharides and COD) in the sludge supernatant. Increasing the SRT from 9 to 40 days seems to slightly reduce the level of organic compounds (probable biodegradation), but the concentrations increased when SRT changes from 40 days to 106 days (probable accumulation of non biodegradable compounds).
Membrane bioreactor versus conventional activated sludge system: population dynamics of nitrifiers
Authors: Manser R. , Gujer W. , Siegrist H.
Published: May 2018

Although membrane bioreactors have attracted increasing attention in recent years, little research has been undertaken on the influence of the membrane separation on the microbial community composition. This paper compares the startup behaviour and the performance of the subsequent eight months of a membrane bioreactor with a conventional activated sludge pilot plant. Both plants were operated in parallel at the same sludge age and treated the same domestic wastewater. The identification of the nitrifying community composition using fluorescent in situ hybridization revealed only minor differences between the two reactors for both ammonia-oxidizing bacteria and nitrite-oxidizing bacteria. Accordingly, both systems exhibited the same maximum nitrification rates. Confocal laser scanning microscopy showed that the aggregates formed by nitrifying bacteria were located mostly in the inner part of the flocs and were overgrown by heterotrophic bacteria. It is concluded that the membrane separation itself does affect neither the nitrifying community composition nor the nitrification performance. However, impacts on kinetic parameters are emphasized.
Nitrification parameter measurement for plant design: experience and experimental issues with new methods
Authors: Jones R.M. , Bye C.M. , Dold P.L.
Published: May 2018

Nitrification kinetics are important for process design, optimization, and capacity rating of activated sludge wastewater treatment plants. A Water Environment Research Foundation (WERF) project on Methods for Wastewater Characterization in Activated Sludge Modeling (WERF, 2003) focused significantly on the development of procedures for measuring the nitrifier maximum specific growth rate, μAUT. In addition, the importance of (and lack of data for) the nitrifier decay rate, bAUT, was identified. This paper describes three bench-scale methods for measuring μAUT: the Low F/M SBR, Washout and High F/M methods. During the WERF project, the importance of pH and temperature control was investigated briefly; this paper summarizes further experimental work performed to address these issues. A summary of μAUT measurements in a number of locations and using the different measurement techniques is provided.
Chemical denitrification for nitrogen removal from landfill leachate
Authors: Nikolić A. , Hultman B.
Published: May 2018

A new system that removes nitrogen from landfill leachate and other waste waters with similar properties has been proposed with nitritation (i.e. oxidation of ammonium to nitrite) of half of the influent ammonium followed by chemical denitrification with a reaction between equal amounts of ammonium and nitrite to form nitrogen gas. Chemical denitrification occurs at high concentrations and the reactions were studied in combination with a concentration step. Studied concentration methods were freezing/thawing and evaporation/drying. Chemical denitrification is well-known in inorganic chemistry and has been observed in natural systems.

Studies in laboratory were focused on chemical denitrification and showed that nearly complete removal of soluble nitrogen can be obtained in evaporation/drying of water solutions or leachate with equal amounts of ammonium and nitrite. Freezing/drying was less efficient with a removal of about 50–60% at high initial concentrations. Chemical denitrification is much influenced by concentration, pH-value, temperature and some compounds in leachate have an inhibiting effect on the reaction. Factors as safety (ammonium nitrite as a salt is explosive above 60°C) and possible side-reactions as formation of ammonia and nitrogen oxides must be carefully evaluated before use in full-scale. Conductivity is a suitable parameter to follow-up the chemical denitrification process.
Phosphorus recycling in sewage treatment plants with biological phosphorus removal
Authors: Heinzmann B.
Published: May 2018

In this paper, phosphorus balances are calculated for the wastewater purification and sludge treatment stages for wastewater treatment plants (WWTPs) applying Enhanced Biological Phosphorus Removal (EBPR). The possible P-recovery potential is then estimated and evaluated regarding different locations along the process of wastewater purification and sludge treatment, taking the different phosphorus bonding forms into account. Caused by the more favourable bonding forms in the excess sludge as well as possibly also in the sludge ash a recovery of the phosphorus seems especially favoured for WWTPs with EBPR.

The processes available for a P recycling are named, and special regard is given to the Phostrip-process, which is a possible recycling process already tested in practice. Further R&D demand consists in basic research regarding disintegration, fermentation or acidic total digestion of excess sludge followed by phosphorus precipitation including separation of the precipitates, MAP-precipitation and separation from digested sludge and on the ability to extract phosphorus and heavy metals from sewage sludge ash. These investigations are a precondition to enable purposeful process developments.

At the present state the cost of recycled phosphorus earned from wastewater, sludge and ash, respectively, are a multiple higher than the costs for raw phosphate taking into account the suitable processes. Thus, up to now no phosphorus recycling with a defrayal of costs is possible. The future importance of phosphorus recycling will depend on the market price for raw phosphate, the recycling costs and, furthermore, on the general political framework.
Effect of heating temperature and time on the phosphate adsorption capacity of thermally modified copper tailings
Authors: Zhou Runjuan , Wang Youbao , Zhang Ming , Li Jing , Gui Yanan , Tang Yingying , Yu Beixin , Yang Yaru
Published: May 2018

In the present study, copper tailings were treated at different temperatures (50–650 °C) and for various times (0.5–6 hours) and their phosphate adsorption capacity was investigated. The results showed that heating temperature significantly affected adsorption capacity. The highest capacity was observed in treatments at 310–350 °C. Heating time did not influence phosphate adsorption ability of copper tailings. Scanning electron microscopy, Barrett–Joyner–Halenda (BJH), and Fourier transform infrared spectroscopy (FTIR) were employed to characterize untreated copper tailings (raw CT) and copper tailings heated at 340 °C (CT340). The results showed that CT340 had a rougher surface, more and smaller pores, a larger surface area and higher FTIR transmittance than raw CT. These changes in texture might explain the increased phosphate adsorption of thermally modified copper tailings. Mathematical modeling showed that the Langmuir nonlinear model was the best fit to the current data. The maximum adsorption capacities of raw CT and CT340 were predicted as 2.08 mg/g and 14.25 mg/g at 298 K, pH 6.0, respectively.
Análise espacial e mapeamento da ocorrência de corais nos recifes de Picãozinho, João Pessoa-PB, comparativo entre 2001 e 2015/2016
Authors: Souza Maria Cecilia Silva , Vianna Pedro Guedes Costa , Massei Karina , Lima Raoni da Costa , Eloy Christinne Costa
Published: May 2018

Os ecossistemas recifais estão distribuídos em mais de 100 países, sendo reconhecidos como uma das comunidades naturais com maior biodiversidade do Planeta. O litoral do nordeste brasileiro destaca-se por sua exuberância natural, evidenciada principalmente por seus ambientes recifais, atraindo turistas do Brasil e de outros países. Entre os nove estados do Nordeste brasileiro, a Paraíba possui como um grande atrativo os seus ambientes recifais, destacando-se a sua capital João Pessoa, pela grande extensão de recifes de fácil acesso, localizados próximos à costa em suas praias urbanas. Picãozinho, recife costeiro localizado na praia de Tambaú, reune todas essas características, resultando em uma área de fluxo intenso de turismo, o que alerta para a importância de estudos sobre o seu estado de conservação. Este artigo descreve uma análise quantitativa dos corais de Picãozinho comparando dados de 2001 (Costa 2001), com um novo mapeamento realizado entre novembro de 2015 e janeiro de 2016, que objetiva avaliar o ambiente quanto a sua real situação, a partir da distribuição das espécies de corais. Este é o primeiro passo para a criação de uma base de dados espaciais dos ambientes recifais, montados em uma plataforma SIG, viabilizando as condições mínimas para o seu monitoramento. A flexibilidade da metodologia de analise espacial aplicada permite correções e um controle mais eficiente sobre a espacialização das espécies. Isso possibilita que um novo olhar seja posto sobre o ambiente em busca de uma manutenção dos diferentes tipos de corais, além das outras espécies que possuem ligação direta com o ambiente recifal. Os resultados apontam para uma diminuição das espécies quanto à sua diversidade e distribuição nas áreas de intensa visitação. Estes dados nos levam não apenas a refletir sobre o aspecto ambiental, mas também levantam a necessidade de se analisar as questões sociais, econômicas e políticas, para chegarmos no futuro a um modelo de monitoramento e uso que vise a conservação e a sustentabilidade dos recifes do Picãozinho.
Sistema de avaliação espacial do processo de desertificação no semiárido brasileiro
Authors: Lima Ricardo da Cunha Correia , Curi Wilson Fadlo , Santos Ana Paula Silva dos , Peixoto Gabriela Marques , Costa Talita Stael Pimenta da Silva
Published: May 2018

A desertificação é um processo complexo para o qual concorrem fatores de ordem ambiental, social, econômica e institucional. Sua modelagem através de indicadores permanece um desafio para pesquisadores em todo o mundo, em função das múltiplas relações entre a sociedade, o meio ambiente e o desenvolvimento desejado. O presente estudo procurou estruturar um sistema de avaliação da desertificação através de 27 indicadores, sugeridos na literatura relacionada e para os quais foi possível obter dados confiáveis e acessíveis, e organizados segundo o modelo conceitual DPSIR - Força Motriz, Pressão, Estado, Impacto e Resposta. A capacidade dos indicadores descreverem os diversos aspectos da desertificação foi avaliada por um grupo de especialistas de modo a estabelecer um peso para cada um deles. Os indicadores foram calculados e transformados em planos de informação do tipo raster para serem processados através de técnicas de análise de decisão multicritério integradas a sistemas de informações geográficas. Desta maneira, índices multicriteriais de desertificação foram desenvolvidos para cada categoria DPSIR, como instrumentos de avaliação das causas estruturais, causas diretas, susceptibilidade, consequências e respostas da sociedade. Para exemplificar a aplicação da metodologia, um Índice Multicriterial de Desertificação das Pressões (IMD-P) foi calculado para uma porção da região semiárida brasileira, indicando as áreas onde o desmatamento e o manejo inadequado da terra contribuem significativamente para a degradação das terras e, consequentemente, para a desertificação. Palavras-Chave: Indicadores. Análise de Decisão Multicritério. Sistema de informações Geográficas. GIS-MCDA. DPSIR.
Cyclic Peptides that Govern Signal Transduction Pathways: From Prokaryotes to Multi-Cellular Organisms
Authors: Mull Ryan W. , Harrington Anthony , Sanchez Lucia A. , Tal-Gan Yftah
Published: May 2018

Cyclic peptide scaffolds are key components of signal transduction pathways in both prokaryotic
and eukaryotic organisms since they act as chemical messengers that activate or inhibit specific
cognate receptors. In prokaryotic organisms these peptides are utilized in non-essential pathways, such
as quorum sensing, that are responsible for virulence and pathogenicity. In the more evolved eukaryotic
systems, cyclic peptide hormones play a key role in the regulation of the overall function of multicellular
organisms, mainly through the endocrine system. This review will highlight several prokaryote and
eukaryote systems that use cyclic peptides as their primary signals and the potential associated with utilizing
these scaffolds for the discovery of novel therapeutics for a wide range of diseases and illnesses.
Type of Treatment Supporters in Successful Completion of Tuberculosis Treatment: A Retrospective Cohort Study in Pakistan
Authors: Hussain Sana , Hasnain Jamshed , Hussain Zareen , Badshah Masroor , Siddique Hafeez , Fiske Christina , Pettit April
Published: May 2018

Background:

The World Health Organization has recommended a patient-centered approach to tuberculosis drug administration. A central element of the patient-centered strategy is the use of treatment supporters to evaluate and elevate adherence to the treatment regimen and to address poor adherence when it occurs. This study was led to determine the part of various treatment supporters in the successful completion of treatment.

Method:

This study was conducted in two locales of Sindh, Hyderabad and Mirpurkhas. Information gathered included age, gender, regions, sort of treatment supporters (relatives, community and health facility workers) and treatment outcomes.

Results:

Of the 773 patients incorporated into the study, 86.8% picked a family supporter, 7.63% selected community worker and 5.56% chose health facility worker as their treatment supporter. Women and younger patients were more likely to prefer that family members supervise their treatment. Treatment achievement rates among the patients regulated by the three kinds of treatment supporters, were not altogether unique in relation to each other (p=0.23 Chi square).

Conclusion::

The study demonstrates that TB patients ought to be urged to pick the supporter of their inclination as selection of treatment supporter outside the health system does not adversely affect TB treatment outcomes in limited resource settings.
Causation does not explain contextuality
Authors: Shrapnel Sally , Costa Fabio
Published: May 2018

Realist interpretations of quantum mechanics presuppose the existence of elements of reality that are independent of the actions used to reveal them. Such a view is challenged by several no-go theorems that show quantum correlations cannot be explained by non-contextual ontological models, where physical properties are assumed to exist prior to and independently of the act of measurement. However, all such contextuality proofs assume a traditional notion of causal structure, where causal influence flows from past to future according to ordinary dynamical laws. This leaves open the question of whether the apparent contextuality of quantum mechanics is simply the signature of some exotic causal structure, where the future might affect the past or distant systems might get correlated due to non-local constraints. Here we show that quantum predictions require a deeper form of contextuality: even allowing for arbitrary causal structure, no model can explain quantum correlations from non-contextual ontological properties of the world, be they initial states, dynamical laws, or global constraints.
Microfabrication of position reference patterns onto glass microscope slides for high-accurate analysis of dynamic cellular events
Authors: Galeano July A. , Sandoz Patrick , Zarzycki Artur , Robert Laurent , Jaramillo Juan M.
Published: May 2018

Glass microscopes slides are widely used as in situ base-substrates carrying diverse micro-fabricated systems or elements. For such purposes, the micro-fabrication process consists in transferring a pre-defined design onto the substrate made of a glass microscope slide. This is known as patterning, which is a technique that can also be used in transferring specific designs that allows region of interest (ROI) recovery under the microscope. In those cases, two main challenges appear: 1) Disturbances in light transmission should remain minimum to keep the high quality of observation of the object of interest under the microscope. 2) The pattern-size should then be small enough but, however, larger than the diffraction limit to be observable satisfactorily for positioning purposes. In this article, we present the procedures involved in the microfabrication of Pseudo-Periodic Patterns (PPP) encrypting the absolute position of an extended area. Those patterns are embedded in Pétri dishes in order to allow the highaccurate retrieval of absolute position and orientation. The presented microfabrication is based in a technique known as lift-off, which after parameter adjustment, allows the obtaining of PPP fulfilling the two previously mentioned requirements. The results report on PPP realized on glass microscope slides and composed by 2µm side dots made of aluminum with a thickness of 30nm.
Development and implementation of technologies for physical telerehabilitation in Latin America:
Authors: Narváez Fabián , Marín-Castrillón Diana M. , Cuenca Ma. Cisne , Latta Ma. Augusta
Published: May 2018

Telerehabilitation has arised by the inclusion of emerging technologies for capturing, transmitting, analyzing and visualizing movement patterns associated to musculoskeletal disorders. This therapeutic strategy enables to carry out diagnosis processes and provide rehabilitation treatments. This paper presents a systematic review of the current development and implementation of telerehabilitation technologies in Latin America. The main goal is to explore the scientific literature and dissemination sources to establish if such technologies have been introduced in this region. Likewise, this work highlights existing prototypes or systems that are to being used or that are still under development. A systematic search strategy was conducted by two different searches: the first one involves a rigorous literature search from the most relevant scientific digital repositories; the second one included telerehabilitation projects and programs retrieved by an advanced Google search. A total of 53 documents from six countries (Colombia, Brazil, Mexico, Ecuador, Chile and Argentina) were found. Most of them were focused on academic and research initiatives to develop in-home telerehabilitation technologies for pediatric and elderly populations affected by motor and functional impairment, cerebral palsy, neurocognitive disorders and stroke. The analysis of the findings revealed the need for a comprehensive approach that integrates health care and the social system to increase the current availability of telerehabilitation initiatives in Latin America.
Multi-atlas label fusion by using supervised local weighting for brain image segmentation
Authors: Cárdenas-Peña David , Fernández Eduardo , Ferrández-Vicente José M. , Castellanos-Domínguez German
Published: May 2018

The automatic segmentation of interest structures is devoted to the morphological analysis of brain magnetic resonance imaging volumes. It demands significant efforts due to its complicated shapes and since it lacks contrast between tissues and intersubject anatomical variability. One aspect that reduces the accuracy of the multi-atlasbased segmentation is the label fusion assumption of one-to-one correspondences between targets and atlas voxels. To improve the performance of brain image segmentation, label fusion approaches include spatial and intensity information by using voxel-wise weighted voting strategies. Although the weights are assessed for a predefined atlas set, they are not very efficient for labeling intricate structures since most tissue shapes are not uniformly distributed in the images. This paper proposes a methodology of voxel-wise feature extraction based on the linear combination of patch intensities. As far as we are concerned, this is the first attempt to locally learn the features by maximizing the centered kernel alignment function. Our methodology aims to build discriminative representations, deal with complex structures, and reduce the image artifacts. The result is an enhanced patch-based segmentation of brain images. For validation, the proposed brain image segmentation approach is compared against Bayesian-based and patch-wise label fusion on three different brain image datasets. In terms of the determined Dice similarity index, our proposal shows the highest segmentation accuracy (90.3% on average); it presents sufficient artifact robustness, and provides suitable repeatability of the segmentation results.
Advances in biomedical engineering: a call for enhancing empirical research
Authors: Orozco-Duque Andrés , Novák Daniel
Published: May 2018

Advances in biomedical engineering (BME) imply the existence of research groups working in multidisciplinary teams to understand physiological processes and develop methods and tools for diagnostics and therapeutics. Multidisciplinary teams include physicians, biologists, physicists, mathematicians and engineers from different disciplines: electrical and electronics, computer sciences, materials, mechanical, chemical, among others. Lately, BME has become a bridge joining these disciplines. Therefore, successful BME projects involve not only a deep knowledge of the specific discipline, but also an understanding of the physiological phenomena under study.
The effects of cultural dimensions on the internal audit function – A worldwide comparison of internal audit characteristics.
Authors: Eulerich Marc , Ratzinger-Sakel Nicole
Published: May 2018

This study seeks to analyze if the national culture has an effect on different characteristics of the internal audit function (IAF). Using an international sample of companies from different industries together with the five cultural dimensions of Hofstede (2001) as proxies for national culture, this study analyzes how cultural differences across countries affect the structure and work of the internal audit function (IAF). In doing so, we estimate linear, logistic and ordered logistic regressions to test the effects of the different country-level cultural variables on our dependent IAF variables. While our research focus is unique, a recent paper by Bik and Hooghiemstra (2017), which has a different purpose and examines the effect of national culture on auditor-in-charge involvement, uses a similar regression approach. The results show a positive association between the different cultural dimensions, e.g. long-term orientation and uncertainty avoidance, and an objective and independent IAF. In contrast, other dimensions do not seem to be supportive for an objective and independent IAF. This exploratory study contributes to the literature in at least two ways. First, a new research approach and dimension of IAF research is used. Second, the findings indicate that different cultural dimensions have significant effects on specific IAF characteristics. The findings can help internal audit practitioners and their stakeholders to double-check if specific dimensions of national culture have an impact on IAFs’ characteristics. This study uses a unique research focus and an international dataset to examine the influence of national culture on IAF in multiple dimensions. All five Hofstede’s cultural dimensions are used to obtain a holistic of view on the effects of national and they are linked to relevant proxies which describe the culture and work of the IAF. Our results should open new research streams on internationalization and effects of culture on the IAF.
Mini-Dose Glucagon as a Novel Approach to Prevent Exercise-Induced Hypoglycemia in Type 1 Diabetes
Authors: Rickels Michael R. , DuBose Stephanie N. , Toschi Elena , Beck Roy W. , Verdejo Alandra S. , Wolpert Howard , Cummins Martin J. , Newswanger Brett , Riddell Michael C. ,   T1D Exchange Mini-Dose Glucagon Exercise Study Group, Rickels Michael , Peleckis Amy , Evangelisti Margaret , Dalton-Bakes Cornelia , Fuller Carissa , Toschi Elena , Wolpsert Howard , Middelbeek Roeland , Cherng Jye Louis Seow , Shahar Jacqueline , Slyne Christine , Edwards Stephanie , Castillo Astrid Atakov , DuBose Stephanie N. , Beck Roy W. , Verdejo Alandra S. , Cummins Martin , Newswanger Brett , Prestrelski Steve
Published: May 2018

OBJECTIVE

Patients with type 1 diabetes who do aerobic exercise often experience a drop in blood glucose concentration that can result in hypoglycemia. Current approaches to prevent exercise-induced hypoglycemia include reduction in insulin dose or ingestion of carbohydrates, but these strategies may still result in hypoglycemia or hyperglycemia. We sought to determine whether mini-dose glucagon (MDG) given subcutaneously before exercise could prevent subsequent glucose lowering and to compare the glycemic response to current approaches for mitigating exercise-associated hypoglycemia.

RESEARCH DESIGN AND METHODS

We conducted a four-session, randomized crossover trial involving 15 adults with type 1 diabetes treated with continuous subcutaneous insulin infusion who exercised fasting in the morning at ∼55% VO2max for 45 min under conditions of no intervention (control), 50% basal insulin reduction, 40-g oral glucose tablets, or 150-μg subcutaneous glucagon (MDG).

RESULTS

During exercise and early recovery from exercise, plasma glucose increased slightly with MDG compared with a decrease with control and insulin reduction and a greater increase with glucose tablets (P < 0.001). Insulin levels were not different among sessions, whereas glucagon increased with MDG administration (P < 0.001). Hypoglycemia (plasma glucose <70 mg/dL) was experienced by six subjects during control, five subjects during insulin reduction, and none with glucose tablets or MDG; five subjects experienced hyperglycemia (plasma glucose ≥250 mg/dL) with glucose tablets and one with MDG.

CONCLUSIONS

MDG may be more effective than insulin reduction for preventing exercise-induced hypoglycemia and may result in less postintervention hyperglycemia than ingestion of carbohydrate.