bluuebunny/crossref_metadata_2025 huggingface dataset:
Culture experiments with a freshwater cladoceran, Ceriodaphnia quadrangula (O. F. Müller, 1785), as suitable live food for Mayan cichlid (Cichlasoma urophthalmus) larvae
Authors: Farhadian Omidvar , Khanjani Mohammad Hossein , Keivany Yazdan , Ebrahimi Eisa
Published: November 2013

Effects of five different diets of green microalgae, Scenedesmus quadricauda (S), poultry manure (P), cattle manure (C), and two mixed diet of P+C (PC) and S+P+C (SPC); and interaction effects of water temperature (20, 25, 30°C) and photoperiod (24:0, 0:24, and 12:12, hours light: hours dark) on production and growth of Ceriodaphnia quadrangula were examined separately. Then, mass cultivation of C. quadrangula and its application for rearing of an ornamental fish larva, Mayan cichlid (Cichlasoma urophthalmus) were carried out. Results showed that mean population density and specific growth rate (SGR) of C. quadrangula obtained 0.15-3.70 ind. mL-1 (150-3700 ind. mL-1) and 0.019-0.18 day-1, respectively, maximum with S diet and minimum with C diet. The better mean population density and SGR for C. quadrangula determined at interactions 25 ºC with 24:0 and 12: 12, L:D, respectively, which was significantly higher than that at interactions 20 ºC and 30 ºC. Nutritional analyses showed that protein and lipid contents of C. quadrangula were 54% and 12.3% dry weight, respectively. The fatty acid contents of C. quadrangula were 27.3% and 63.7% of saturated and unsaturated fatty acids, respectively. Among PUFAs (Polyunsaturated Fatty Acids) content, 18:2n-6 and 18:3n-3 were in highest level. Early cichlid larvae (5-weeks-old, 15.8 mm length and 110 mg weight) and advanced larvae (10-weeks-old, 25.6 mm length and 240 mg weight) consumed C. quadrangula at range 220–584 ind. day-1 larvae-1 and 528–1956 ind. day-1 larvae-1, respectively, as well as suitable growth and survival rate. This study demonstrated that C. quadrangula could be used as live feed purposes for larval rearing in aquaculture.
Efeito de um evento extremo de enchente sobre os decápodos infralitorais do estuário do Itajaí-Açu, SC, Brasil
Authors: Leite Isabel do Prado , Pezzuto Paulo Ricardo
Published: November 2013

Estuaries are coastal water bodies with great economic and biological importance. The benthic organisms play a significant role in these environments as regulators or modifiers of physical, chemical and biological processes. This study aimed to evaluate the spatial and temporal distribution of the infralittoral decapods in the Itajaí-Açu estuary, investigating factors that influence their distribution and possible effects of a flood event on the benthic community. Six sampling points were established along the longitudinal gradient of the estuary. Monthly samples were taken with otter trawls between May 2008 and July 2010. Crustaceans were separated, packed in labeled plastic bags and kept frozen until processing. Physicochemical data of the water column were also collected with the aid of a multianalyser. In the laboratory the organisms were identified, measured and weighed individually. The analysis of variations in relative abundance and biomass of the species and the analysis of the environmental variables were conducted by using descriptive statistics. The relationship of environmental variables with the biotic variables was examined by Spearman correlation coefficient (p < 0.05). Box-plot graphics of environmental variables in which the main species occurred were generated to identify ranges of environmental conditions under which each species occurred. The results showed that pH, salinity and dissolved oxygen are related to the penetration of the salt wedge, while temperature shows a seasonal pattern. The estuary showed a low richness (14 species), mainly in the two months after the flood of November 2008, and high dominance. It was possible to realize that many factors act on the estuary which make difficult to establish relationships between the biota and environmental variables in particular. There was an increase in abundance and biomass between February and July 2009, which suggest that the fauna was able to recover from the flood.
First report of Linguadactyloides brinkmanni (Monogenoidea: Linguadactyloidinae) on hybrids of Colossoma macropomum x Piaractus mesopotamicus (Characidae) from South America
Authors: Dias Márcia Kelly Reis , Tavares-Dias Marcos , Marchiori Natalia
Published: November 2013

This study presents the first report of infection by Linguadactyloides brinkmanni Thatcher & Krytsky, 1983 (Monogenoidea, Dactylogyridae, Linguadactyloidinae) on the gills of the hybrid tambatinga (Colossoma macropomum x Piaractus brachypomus) from fish farms from the city of Macapá, state of Amapá, eastern Amazonia, Brazil. Out of 201 hybrid tambatinga examined, ten had their gills infested by L. brinkmanni (prevalence= 4.9%). From these hosts, 21 specimens of L. brinkmanni were collected and the mean intensity of infestation was 2.1 (1-4 parasites). This study expands the distribution of this monogenoidean for a new host.
Dualizing complexes and homomorphisms vanishing in Koszul homology
Authors: Majadas Javier
Published: November 2013

Let C be a semidualizing complex over a noetherian local ring A. If there exists a local homomorphism

A
→
B

${A \rightarrow B}$

vanishing at the level of the first Koszul homology modules (e.g. the Frobenius endomorphism in positive characteristic, or any homomorphism factorizing through a regular local ring) and of finite Gorenstein dimension relative to C, then C is dualizing.
Analysis of the effect of molecular weight and testing rate on shear strength of epoxidized natural rubber-based adhesives with a statistical model
Authors: Poh Beng Teik , Khan Imran
Published: November 2013

The effect of the molecular weight and testing rate on shear strength of epoxidized natural rubber (ENR 25)-based adhesives with statistical model was investigated using gum rosin as the tackifying resin. Toluene and polyethylene terephthalate (PET) were used as the solvent and substrate, respectively, throughout the study. A SHEEN hand coater was used to coat the adhesive on the substrate at a coating thickness of 120 μm. All the adhesion properties were determined by a Lloyd Adhesion Tester operating at different rates of testing. Result shows that shear strength increases up to an optimum molecular weight of 6.5×104 ENR 25. Shear strength increases with coating thickness, an observation that is ascribed to the increasing amount of adhesive present in the coating layer, which enhances the shear resistance of the adhesive. It also increases with increase in rate of testing, a phenomenon that is associated with the viscoelastic response of the adhesive.
On Calling the Gods by the Right Names
Authors: Rowett Catherine
Published: November 2013

Do you need to know the name of the god you’re praying to? If you get the name wrong what happens to the prayer? What if the god has more than one name? Who gets to decide whether the name works (you or the god or neither)? What are names anyway? Are the names of the gods any different in how they work from any other names? Is there a way of fixing the reference without using the name so as to avoid the problems of optional names? There is a type of formula used in prayer in ancient Greece which I call (in this paper) a “precautionary formula”. The person praying uses expressions like “whether you want to be called [x] or [y]”, and “if this is the name by which you would like to be called”. I also include here the practice of adding definite descriptions that identify the god by means other than the name (e.g. their place of birth or residence, their deeds etc). In this paper I ask what these formulae were for, why so many occur in philosophical work, particularly Plato, and whether the puzzles about the names of the gods go back to the Presocratics.
The prevalence and predictors of active brown adipose tissue in Chinese adults
Authors: Zhang Zhaoyun , Cypess Aaron M , Miao Qing , Ye Hongying , Liew Chong Wee , Zhang Qiongyue , Xue Ruidan , Zhang Shuo , Zuo Chuantao , Xu Zhensheng , Tang Qiqun , Hu Renming , Guan Yihui , Li Yiming
Published: November 2013

Objective

Previous studies have shown that active brown adipose tissue (BAT) is present in adults and may play important roles in the regulation of energy homeostasis. However, nearly every study has been carried out in patients undergoing scanning for cancer surveillance (CS), whose metabolism and BAT activity may not reflect those of healthy individuals. The objective of this study was to investigate the prevalence and predictors of active BAT in Chinese adults, particularly in healthy individuals.

Design

A total of 31 088 consecutive subjects aged ≥18 years who had undergone positron emission tomography/computed tomography (PET/CT) scanning of BAT were evaluated in this study.

Methods

We measured BAT activity via18F-fluorodeoxyglucose PET/CT in subjects who had undergone scanning for either a routine medical checkup (MC) or CS in Shanghai. Then, we investigated the predictors of active BAT, particularly in healthy individuals.

Results

In both groups, the prevalence of BAT was higher in women than in men. Using a multivariate logistic analysis, we found age, sex, BMI, and high thyroid glucose uptake to be significant predictors of BAT activity in the MC group. Similarly, we found age, sex, and BMI to be significant predictors of BAT activity, but not thyroid high glucose uptake, in the CS group.

Conclusions

In Chinese adults, BAT activity inversely correlates with BMI and thyroid high glucose uptake, which reinforces the central role of brown fat in adult metabolism and provides clues to a potential means for treating the metabolic syndrome.
TNFRSF14 deficiency protects against ovariectomy-induced adipose tissue inflammation
Authors: Choi Eun-Kyung , Kim Woon-Ki , Sul Ok-Joo , Park Yun-Kyung , Kim Eun-Sook , Suh Jae-Hee , Yu Rina , Choi Hye-Seon
Published: November 2013

To elucidate the role of tumor necrosis factor receptor superfamily member 14 (TNFRSF14) in metabolic disturbance due to loss of ovarian function, ovariectomy (OVX) was performed in TNFRSF 14-knockout mice. OVX increased fat mass and infiltration of highly inflammatory CD11c cells in the adipose tissue (AT), which was analyzed by flow cytometry, and resulted in disturbance of glucose metabolism, whereas TNFRSF14 deficiency attenuated these effects. TNFRSF14 deficiency decreased recruitment of CD11c-expressing cells in AT and reduced the polarization of bone marrow-derived macrophages to M1. Upon engagement of LIGHT, a TNFRSF14 ligand, TNFRSF14 enhanced the expression of CD11c via generation of reactive oxygen species, suggesting a role of TNFRSF14 as a redox modulator. TNFRSF14 participated in OVX-induced AT inflammation via upregulation of CD11c, resulting in metabolic perturbation. TNFRSF14 could be used as a therapeutic target for the treatment of postmenopausal syndrome by reducing AT inflammation.
Absence of glucocorticoids augments stress-induced Mkp1 mRNA expression within the hypothalamic–pituitary–adrenal axis
Authors: Osterlund Chad D , Thompson Vanessa , Hinds Laura , Spencer Robert L
Published: November 2013

Stress-induced activation of hypothalamic paraventricular nucleus (PVN) corticotropin-releasing hormone (CRH) neurons trigger CRH release and synthesis. Recent findings have suggested that this process depends on the intracellular activation (phosphorylation) of ERK1/2 within CRH neurons. We have recently shown that the presence of glucocorticoids constrains stress-stimulated phosphorylation of PVN ERK1/2. In some peripheral cell types, dephosphorylation of ERK has been shown to be promoted by direct glucocorticoid upregulation of the MAP kinase phosphatase 1 (Mkp1) gene. In this study, we tested the hypothesis that glucocorticoids regulateMkp1mRNA expression in the neural forebrain (medial prefrontal cortex, mPFC, and PVN) and endocrine tissue (anterior pituitary) by subjecting young adult male Sprague–Dawley rats to various glucocorticoid manipulations with or without acute psychological stress (restraint). Restraint led to a rapid increase inMkp1mRNA within the mPFC, PVN, and anterior pituitary, and this increase did not require glucocorticoid activity. In contrast to glucocorticoid upregulation ofMkp1gene expression in the peripheral tissues, we found that the absence of glucocorticoids (as a result of adrenalectomy) augmented basal mPFC and stress-induced PVN and anterior pituitaryMkp1gene expression. Taken together, this study indicates that the presence of glucocorticoids may constrainMkp1gene expression in the neural forebrain and endocrine tissues. This possible constraint may be an indirect consequence of the inhibitory influence of glucocorticoids on stress-induced activation of ERK1/2, a known upstream positive regulator ofMkp1gene transcription.
Late-life effects on rat reproductive system after developmental exposure to mixtures of endocrine disrupters
Authors: Isling Louise Krag , Boberg Julie , Jacobsen Pernille Rosenskjold , Mandrup Karen Riiber , Axelstad Marta , Christiansen Sofie , Vinggaard Anne Marie , Taxvig Camilla , Kortenkamp Andreas , Hass Ulla
Published: November 2013

This study examined late-life effects of perinatal exposure of rats to a mixture of endocrine-disrupting contaminants. Four groups of 14 time-mated Wistar rats were exposed by gavage from gestation day 7 to pup day 22 to a mixture of 13 anti-androgenic and estrogenic chemicals including phthalates, pesticides, u.v.-filters, bisphenol A, parabens, and the drug paracetamol. The groups received vehicle (control), a mixture of all 13 chemicals at 150-times (TotalMix150) or 450-times (TotalMix450) high-end human exposure, or 450-times a mixture of nine predominantly anti-androgenic chemicals (AAMix450). Onset of puberty and estrous cyclicity at 9 and 12 months of age were assessed. Few female offspring showed significantly regular estrus cyclicity at 12 months of age in the TotalMix450 and AAMix450 groups compared with controls. In 19-month-old male offspring, epididymal sperm counts were lower than controls, and in ventral prostate an overrepresentation of findings related to hyperplasia was observed in exposed groups compared with controls, particularly in the group dosed with anti-androgens. A higher incidence of pituitary adenoma at 19 months of age was found in males and females in the AAMix450 group. Developmental exposure of rats to the highest dose of a human-relevant mixture of endocrine disrupters induced adverse effects late in life, manifested as earlier female reproductive senescence, reduced sperm counts, higher score for prostate atypical hyperplasia, and higher incidence of pituitary tumors. These delayed effects highlight the need for further studies on the role of endocrine disrupters in hormone-related disorders in aging humans.
Considerations for estimating daily intake values of nonpersistent environmental endocrine disruptors based on urinary biomonitoring data
Authors: Søeborg Tue , Frederiksen Hanne , Andersson Anna-Maria
Published: November 2013

Human exposure to chemicals may be estimated by back-calculating urinary concentrations resulting from biomonitoring studies if knowledge of the chemical's toxicokinetic properties is available. In this paper, available toxicokinetic data for back-calculating urinary concentrations into daily intake values for bisphenol A (BPA), phthalates, parabens, and triclosan (TCS) are reviewed and knowledge gaps are identified. Human data is evaluated and presented with relevant animal data. Focus is on the recovery of the administered dose, the route of administration, and differences between humans and animals. Two human toxicokinetic studies are currently used to conclude that an oral dose of BPA is recoverable in urine and that no free BPA is present in plasma in spite of several contradicting biominotoring studies. Urinary recovery of an oral dose of phthalates in humans is complicated to assess due to extensive metabolism. In animals using14C-marked phthalates, near-complete recovery is observed. An oral dose of14C-marked parabens is also almost completely recovered in animals. In both humans and animals, however, two unspecific metabolites are formed, which complicates the back-calculation of parabens in humans. The recovery of both oral and dermal TCS in humans has been studied, but due to background levels of TCS, the back-calculation is difficult to perform. In conclusion, due to limited data, reasonable estimates of daily intake values based on urinary data are often not possible to obtain. Several knowledge gaps are identified and new studies are suggested. The route of administration used in toxicokinetic studies often does not match realistic scenarios.
Life-cycle impact ‘cradle to cradle’ of building assemblies
Authors: Silvestre José Dinis , de Brito Jorge , Pinheiro Manuel Duarte
Published: November 2013

This paper proposes an integrated approach for the evaluation of the equivalent cradle-to-cradle life-cycle impact of building assemblies, including the energy, environmental and economic impacts. The application of this approach is exemplified with external walls of buildings. This integrated approach follows European standards: environmental performance is evaluated following a life-cycle assessment methodology; energy performance is gauged by the consumption of energy for heating and cooling; and the economic module is based on the whole-life costing methodology. The use of an environmental impact assessment method that converts the results of impact categories into an economic unit allows the comparison and selection of alternatives through the addition of the energy, environmental and economic life-cycle costs. The main advantage of this approach is the simultaneous comparison of the energy, environmental and economic life-cycle performance of alternatives (that do not have to be functionally equivalent) without the need to change their characteristics to make them comparable.
Experimental study of sediment trapping by geotextile mattress installed with sloping curtain
Authors: Xie L. , Huang W. , Yu Y.
Published: November 2013

ABSTRACT: Geosynthetic structures created for channel erosion protection offer environmental friendly benefits and have demonstrably lower construction and lifetime costs than similar hard structures. A geotextile mattress with a sloping curtain (GMSC) offers an alternative countermeasure against channel erosion. In the present study, experiments were conducted to investigate the working mechanism and effectiveness of GMSCs which were installed on movable beds in a rectangular flume. The bathymetry of the plastic sand beds was measured before and after the tests. The results showed that the presence of the GMSC led to sediment deposition and dune formation at both upstream and downstream edges of the GMSC structure. This will prevent bottom erosion near the structure and increase its stability against flow-induced sediment scour, so that the erodible beds will be protected.
A formula to predict the effect of the variable discharge capacity of prefabricated vertical drains
Authors: Venda Oliveira P.J.
Published: November 2013

ABSTRACT: An empirical formula that relates the discharge capacity of prefabricated vertical drains to the consolidation time and the confining pressure around the drains is proposed in this paper. Firstly, the performance of the formula is analysed based on laboratory and field data published previously. The proposed formula is included in a three-dimensional code, which is used to analyse the behaviour of an embankment built on a soft soil improved with prefabricated vertical drains and to consider the hypotheses of infinite, reduced and variable discharge capacity of the vertical drains. The results of the numerical predictions are compared with field data, in terms of settlement, horizontal displacement and excess pore pressure. In general, the results show that the use of the formula proposed (with suitable parameters) improves the numerical predictions of the settlement and the excess pore pressure during the intermediate phases of consolidation. In terms of the horizontal displacement, the effect of the discharge capacity of the vertical drains appears negligible. The results also reveal some consistency of the parameters in the formula, as the parameters evaluated from experimental data provide the best numerical predictions.
Urban drainage models – simplifying uncertainty analysis for practitioners
Authors: Vezzaro Luca , Mikkelsen Peter Steen , Deletic Ana , McCarthy David
Published: November 2013

There is increasing awareness about uncertainties in the modelling of urban drainage systems and, as such, many new methods for uncertainty analyses have been developed. Despite this, all available methods have limitations which restrict their widespread application among practitioners. Here, a modified Monte-Carlo based method is presented that reduces the subjectivity inherent in typical uncertainty approaches (e.g. cut-off thresholds), while using tangible concepts and providing practical outcomes for practitioners. The method compares the model's uncertainty bands to the uncertainty inherent in each measured/observed datapoint; an issue that is commonly overlooked in the uncertainty analysis of urban drainage models. This comparison allows the user to intuitively estimate the optimum number of simulations required to conduct uncertainty analyses. The output of the method includes parameter probability distributions (often used for sensitivity analyses) and prediction intervals. To demonstrate the new method, it is applied to a conceptual rainfall-runoff model (MOPUS) using a dataset collected from Melbourne, Australia.
Modelling of percolation rate of stormwater from underground infiltration systems
Authors: Burszta-Adamiak Ewa , Łomotowski Janusz
Published: November 2013

Underground or surface stormwater storage tank systems that enable the infiltration of water into the ground are basic elements used in Sustainable Urban Drainage Systems (SUDS). So far, the design methods for such facilities have not taken into account the phenomenon of ground clogging during stormwater infiltration. Top layer sealing of the filter bed influences the infiltration rate of water into the ground. This study presents an original mathematical model describing changes in the infiltration rate variability in the phases of filling and emptying the storage and infiltration tank systems, which enables the determination of the degree of top ground layer clogging. The input data for modelling were obtained from studies conducted on experimental sites on objects constructed on a semi-technological scale. The experiment conducted has proven that the application of the model developed for the phase of water infiltration enables us to estimate the degree of module clogging. However, this method is more suitable for reservoirs embedded in more permeable soils than for those located in cohesive soils.
Visible light-degradation of azo dye methyl orange using TiO2/β-FeOOH as a heterogeneous photo-Fenton-like catalyst
Authors: Xu Zhihui , Zhang Ming , Wu Jingyu , Liang Jianru , Zhou Lixiang , Lǚ Bo
Published: November 2013

In this study, a novel TiO2/β-FeOOH composite photocatalyst was synthesized by a hydrothermal method. X-ray diffraction, Fourier transform infrared spectrum, UV-vis diffuse reflectance spectra and scanning electron microscopy (SEM) were used to characterize the composite photocatalyst. The photocatalytic activity of the prepared composite photocatalyst was evaluated in a heterogeneous photo-Fenton-like process using methyl orange (MO) as target pollutant. The TiO2/β-FeOOH composites exhibited higher photocatalytic activity than pure β-FeOOH and TiO2 under visible-light irradiation. The enhanced photocatalytic activity can be ascribed to the formation of TiO2/β-FeOOH heterostructure, which plays an important role in expanding the photoactivity to the visible light region and in effectively prolonging the lifetime of photoinduced electrons and holes. Further investigation revealed that the 25TiO2/β-FeOOH composite synthesized with the TiO2/Fe3+ in a mole ratio of 25:75 showed the highest catalytic activity.
Sorption of thallium(I) ions by peat
Authors: Robalds Artis , Klavins Maris , Dreijalte Liga
Published: November 2013

The increasing industrial use of thallium has raised the need for removal of this highly toxic element from wastewater. Thallium is more toxic than cadmium, copper, zinc, lead and mercury and as it is easily accumulated in humans, animals and plants, it poses a threat to both the environment and human health. Peat has been used as an effective, relatively cheap and easily available sorbent to treat waters containing heavy metals. In this study, peat was characterized and used as sorbent for the removal of Tl(I) ions from aqueous solution. The effect of initial Tl(I) concentration, pH, contact time, temperature and ionic strength was studied in batch mode. The maximum sorption capacity of peat reached 24.14 mg/g at 20 °C and initial Tl(I) concentration of 500 mg/L. Sorption capacity was found to be pH dependent and maximum uptake occurred at pH 10. Kinetic data revealed that sorption was relatively rapid – 82.8% of Tl(I) ions were sorbed in the first 10 min. The kinetics of sorption was analyzed using pseudo-first order and pseudo-second order models. Results show that peat can be used as an effective sorbent to remove Tl(I) ions from aqueous solutions.
Biological Cr(VI) removal using bio-filters and constructed wetlands
Authors: Michailides Michail K. , Sultana Mar-Yam , Tekerlekopoulou Athanasia G. , Akratos Christos S. , Vayenas Dimitrios V.
Published: November 2013

The bioreduction of hexavalent chromium from aqueous solution was carried out using suspended growth and packed-bed reactors under a draw-fill operating mode, and horizontal subsurface constructed wetlands. Reactors were inoculated with industrial sludge from the Hellenic Aerospace Industry using sugar as substrate. In the suspended growth reactors, the maximum Cr(VI) reduction rate (about 2 mg/L h) was achieved for an initial concentration of 12.85 mg/L, while in the attached growth reactors, a similar reduction rate was achieved even with high initial concentrations (109 mg/L), thus confirming the advantage of these systems. Two horizontal subsurface constructed wetlands (CWs) pilot-scale units were also built and operated. The units contained fine gravel. One unit was planted with common reeds and one was kept unplanted. The mean influent concentrations of Cr(VI) were 5.61 and 5.47 mg/L for the planted and unplanted units, respectively. The performance of the planted CW units was very effective as mean Cr(VI) removal efficiency was 85% and efficiency maximum reached 100%. On the contrary, the unplanted CW achieved very low Cr(VI) removal with a mean value of 26%. Both attached growth reactors and CWs proved efficient and viable means for Cr(VI) reduction.
Performance assessment of pilot horizontal sub-surface flow constructed wetlands for removal of diesel from wastewater by Scirpus grossus
Authors: Al-Baldawi Israa Abdulwahab , Sheikh Abdullah Siti Rozaimah , Anuar Nurina , Suja Fatihah , Idris Mushrifah
Published: November 2013

One of the appropriate development technology options for the treatment of wastewater contaminated with diesel is constructed wetlands (CWs). Throughout 72 days of exposure, sampling was carried out for monitoring of physical parameters, plant growth and the efficiency of total petroleum hydrocarbon (TPH) removal, as an indication for diesel contamination, to assess the pilot-scale performance. Four pilot CWs with a horizontal sub-surface flow system were applied using the bulrush of Scirpus grossus. The CWs were loaded with different diesel concentrations of 0, 0.1, 0.2 and 0.25% (Vdiesel/Vwater). The TPH removal efficiencies were 82, 71, and 67% at the end of 72 days for diesel concentrations of 0.1, 0.2, and 0.25% respectively. In addition, the high removal efficiency of total suspended solids and chemical oxygen demand (COD) were 100 and 75.4% respectively, for a diesel concentration of 0.1%. It was concluded that S. grossus is a potential plant that can be used in a well-operated CW for restoring 0.1% diesel-contaminated water.
Adsorption of methylene blue and Congo red from aqueous solution by activated carbon and carbon nanotubes
Authors: Szlachta M. , Wójtowicz P.
Published: November 2013

This study was conducted to determine the adsorption removal of dyes by powdered activated carbon (PAC, Norit) and multi-walled carbon nanotubes (MWCNTs, Chinese Academy of Science) from an aqueous solution. Methylene blue (MB) and Congo red (CR) were selected as model compounds. The adsorbents tested have a high surface area (PAC 835 m2/g, MWCNTs 358 m2/g) and a well-developed porous structure which enabled the effective treatment of dye-contaminated waters and wastewaters. To evaluate the capacity of PAC and MWCNTs to adsorb dyes, a series of batch adsorption experiments was performed. Both adsorbents exhibited a high adsorptive capacity for MB and CR, and equilibrium data fitted well with the Langmuir model, with the maximum adsorption capacity up to 400 mg/g for MB and 500 mg/g for CR. The separation factor, RL, revealed the favorable nature of the adsorption process under experimental conditions. The kinetics of adsorption was studied at various initial dye concentrations and solution temperatures. The pseudo-second-order model was used for determining the adsorption kinetics of MB and CR. The data obtained show that adsorption of both dyes was rapid in the initial stage and followed by slower processing to reach the plateau. The uptake of dyes increased with contact time, irrespective of their initial concentration and solution temperature. However, changes in the solution temperature did not significantly influence dye removal.
Surface coating with Ca(OH)2 for improvement of the transport of nanoscale zero-valent iron (nZVI) in porous media
Authors: Wei Cai-jie , Li Xiao-yan
Published: November 2013

A novel thermal deposition method was developed to coat Ca(OH)2 on the surface of nanoscale zero-valent iron (nZVI). The nZVI particles with the Ca(OH)2 coating layer, nZVI/Ca(OH)2, had a clear core-shell structure based on the transmission electron microscopy observations, and the Ca(OH)2 shell was identified as an amorphous phase. The Ca(OH)2 coating shell would not only function as an effective protection layer for nZVI but also improve the mobility of nZVI in porous media for its use in environmental decontamination. A 10% Ca/Fe mass ratio was found to result in a proper thickness of the Ca(OH)2 shell on the nZVI surface. Based on the filtration tests in sand columns, the Ca(OH)2-based surface coating could greatly improve the mobility and transport of nZVI particles in porous media. In addition, batch experiments were conducted to evaluate the reactivity of Ca(OH)2-coated nZVI particles for the reduction of Cr(VI) and its removal from water.
The effect of several parameters on catalytic denitrification of water by the use of H2 in the presence of O2 over metal supported catalysts
Authors: Theologides C. P. , Savva P. G. , Olympiou G. G. , Pantelidou N. A. , Constantinou B. K. , Chatziiona V. K. , Valanidou L. Y. , Piskopianou C. T. , Costa C. N.
Published: November 2013

The present paper involves a detailed study of the selective catalytic reduction of nitrates in aqueous mediums by the use of H2 in the presence of O2 over monometallic and bimetallic supported catalysts. In this study, an attempt has been made to improve the denitrification efficiency (XNO3−, SN2) of several catalysts by regulating some experimental parameters that are involved in the process. Therefore, the effects of the type of reactor (semi-batch reactor vs continuous flow reactor), the nature of the active phase (Pd, Cu, and Pd-Cu) and the particle size of γ-Al2O3 spheres (particle diameter = 1.8 mm and 3 mm) on catalytic activity and reaction selectivity, as well as the adsorption capacity of γ-Al2O3 spheres for nitrates, were examined. As the review indicates, most of the research has so far been conducted on batch or semi-batch reactors. This study successfully demonstrates the benefits of using a continuous flow reactor in terms of catalytic activity (XNO3−, %) and reaction selectivity (SN2, %). Another important aspect of this study is the crucial role of bimetallic Pd-Cu clusters for the prevention of NH4+ formation. Moreover, the use of 1.8 mm diameter γ-Al2O3 spheres as a support was proved to significantly enhance the catalytic performance of bimetallic Pd-Cu catalysts towards nitrate reduction compared to 3 mm diameter γ-Al2O3 spheres. This difference may be attributed to mass (NO3−, OH−) transfer effects (external mass transfer phenomena).
On logical hierarchies within FO^2-definable languages
Authors: Kufleitner Manfred , Weil Pascal
Published: November 2013

We consider the class of languages defined in the 2-variable fragment of the
first-order logic of the linear order. Many interesting characterizations of
this class are known, as well as the fact that restricting the number of
quantifier alternations yields an infinite hierarchy whose levels are varieties
of languages (and hence admit an algebraic characterization). Using this
algebraic approach, we show that the quantifier alternation hierarchy inside
FO^{2}[<] is decidable within one unit. For this purpose, we relate each level
of the hierarchy with decidable varieties of languages, which can be defined in
terms of iterated deterministic and co-deterministic products. A crucial notion
in this process is that of condensed rankers, a refinement of the rankers of
Weis and Immerman and the turtle languages of Schwentick, Th\'erien and
Vollmer.
Strongly Complete Logics for Coalgebras
Authors: Kurz Alexander , Rosicky Jiri
Published: November 2013

Coalgebras for a functor model different types of transition systems in a
uniform way. This paper focuses on a uniform account of finitary logics for
set-based coalgebras. In particular, a general construction of a logic from an
arbitrary set-functor is given and proven to be strongly complete under
additional assumptions. We proceed in three parts. Part I argues that sifted
colimit preserving functors are those functors that preserve universal
algebraic structure. Our main theorem here states that a functor preserves
sifted colimits if and only if it has a finitary presentation by operations and
equations. Moreover, the presentation of the category of algebras for the
functor is obtained compositionally from the presentations of the underlying
category and of the functor. Part II investigates algebras for a functor over
ind-completions and extends the theorem of J{\'o}nsson and Tarski on canonical
extensions of Boolean algebras with operators to this setting. Part III shows,
based on Part I, how to associate a finitary logic to any finite-sets
preserving functor T. Based on Part II we prove the logic to be strongly
complete under a reasonable condition on T.
Wreath Products of Forest Algebras, with Applications to Tree Logics
Authors: Bojanczyk Mikolaj , Walukiewicz Igor , Straubing Howard
Published: November 2013

We use the recently developed theory of forest algebras to find algebraic
characterizations of the languages of unranked trees and forests definable in
various logics. These include the temporal logics CTL and EF, and first-order
logic over the ancestor relation. While the characterizations are in general
non-effective, we are able to use them to formulate necessary conditions for
definability and provide new proofs that a number of languages are not
definable in these logics.
Completeness for the coalgebraic cover modality
Authors: Kupke Clemens , Kurz Alexander , Venema Yde
Published: November 2013

We study the finitary version of the coalgebraic logic introduced by L. Moss.
The syntax of this logic, which is introduced uniformly with respect to a
coalgebraic type functor, required to preserve weak pullbacks, extends that of
classical propositional logic with a so-called coalgebraic cover modality
depending on the type functor. Its semantics is defined in terms of a
categorically defined relation lifting operation. As the main contributions of
our paper we introduce a derivation system, and prove that it provides a sound
and complete axiomatization for the collection of coalgebraically valid
inequalities. Our soundness and completeness proof is algebraic, and we employ
Pattinson's stratification method, showing that our derivation system can be
stratified in countably many layers, corresponding to the modal depth of the
formulas involved. In the proof of our main result we identify some new
concepts and obtain some auxiliary results of independent interest. We survey
properties of the notion of relation lifting, induced by an arbitrary but fixed
set functor. We introduce a category of Boolean algebra presentations, and
establish an adjunction between it and the category of Boolean algebras. Given
the fact that our derivation system involves only formulas of depth one, it can
be encoded as a endo-functor on Boolean algebras. We show that this functor is
finitary and preserves embeddings, and we prove that the Lindenbaum-Tarski
algebra of our logic can be identified with the initial algebra for this
functor.
Two for the Price of One: Lifting Separation Logic Assertions
Authors: Thamsborg Jacob , Birkedal Lars , Yang Hongseok
Published: November 2013

Recently, data abstraction has been studied in the context of separation
logic, with noticeable practical successes: the developed logics have enabled
clean proofs of tricky challenging programs, such as subject-observer patterns,
and they have become the basis of efficient verification tools for Java
(jStar), C (VeriFast) and Hoare Type Theory (Ynot). In this paper, we give a
new semantic analysis of such logic-based approaches using Reynolds's
relational parametricity. The core of the analysis is our lifting theorems,
which give a sound and complete condition for when a true implication between
assertions in the standard interpretation entails that the same implication
holds in a relational interpretation. Using these theorems, we provide an
algorithm for identifying abstraction-respecting client-side proofs; the proofs
ensure that clients cannot distinguish two appropriately-related module
implementations.
Predicate Generation for Learning-Based Quantifier-Free Loop Invariant Inference
Authors: Lee Wonchan , Jung Yungbum , Wang Bow-yaw , Yi Kwangkuen
Published: November 2013

We address the predicate generation problem in the context of loop invariant
inference. Motivated by the interpolation-based abstraction refinement
technique, we apply the interpolation theorem to synthesize predicates
implicitly implied by program texts. Our technique is able to improve the
effectiveness and efficiency of the learning-based loop invariant inference
algorithm in [14]. We report experiment results of examples from Linux,
SPEC2000, and Tar utility.
Efficient Interpolant Generation in Satisfiability Modulo Linear Integer Arithmetic
Authors: Griggio Alberto , Le Thi Thieu Hoa , Sebastiani Roberto
Published: November 2013

The problem of computing Craig interpolants in SAT and SMT has recently
received a lot of interest, mainly for its applications in formal verification.
Efficient algorithms for interpolant generation have been presented for some
theories of interest ---including that of equality and uninterpreted functions,
linear arithmetic over the rationals, and their combination--- and they are
successfully used within model checking tools. For the theory of linear
arithmetic over the integers (LA(Z)), however, the problem of finding an
interpolant is more challenging, and the task of developing efficient
interpolant generators for the full theory LA(Z) is still the objective of
ongoing research. In this paper we try to close this gap. We build on previous
work and present a novel interpolation algorithm for SMT(LA(Z)), which exploits
the full power of current state-of-the-art SMT(LA(Z)) solvers. We demonstrate
the potential of our approach with an extensive experimental evaluation of our
implementation of the proposed algorithm in the MathSAT SMT solver.
Complexity classifications for different equivalence and audit problems for Boolean circuits
Authors: BÃ¶hler Elmar , Creignou Nadia , Galota Matthias , Reith Steffen , Schnoor Henning , Vollmer Heribert
Published: November 2013

We study Boolean circuits as a representation of Boolean functions and
consider different equivalence, audit, and enumeration problems. For a number
of restricted sets of gate types (bases) we obtain efficient algorithms, while
for all other gate types we show these problems are at least NP-hard.
Soundness of Unravelings for Conditional Term Rewriting Systems via Ultra-Properties Related to Linearity
Authors: Nishida Naoki , Sakai Masahiko , Sakabe Toshiki
Published: November 2013

Unravelings are transformations from a conditional term rewriting system
(CTRS, for short) over an original signature into an unconditional term
rewriting systems (TRS, for short) over an extended signature. They are not
sound w.r.t. reduction for every CTRS, while they are complete w.r.t.
reduction. Here, soundness w.r.t. reduction means that every reduction sequence
of the corresponding unraveled TRS, of which the initial and end terms are over
the original signature, can be simulated by the reduction of the original CTRS.
In this paper, we show that an optimized variant of Ohlebusch's unraveling for
a deterministic CTRS is sound w.r.t. reduction if the corresponding unraveled
TRS is left-linear or both right-linear and non-erasing. We also show that
soundness of the variant implies that of Ohlebusch's unraveling. Finally, we
show that soundness of Ohlebusch's unraveling is the weakest in soundness of
the other unravelings and a transformation, proposed by Serbanuta and Rosu, for
(normal) deterministic CTRSs, i.e., soundness of them respectively implies that
of Ohlebusch's unraveling.
Finite dimensional Hilbert spaces are complete for dagger compact closed categories
Authors: Selinger Peter
Published: November 2013

We show that an equation follows from the axioms of dagger compact closed
categories if and only if it holds in finite dimensional Hilbert spaces.
Isomorphisms of types in the presence of higher-order references (extended version)
Authors: Clairambault Pierre
Published: November 2013

We investigate the problem of type isomorphisms in the presence of
higher-order references. We first introduce a finitary programming language
with sum types and higher-order references, for which we build a fully abstract
games model following the work of Abramsky, Honda and McCusker. Solving an open
problem by Laurent, we show that two finitely branching arenas are isomorphic
if and only if they are geometrically the same, up to renaming of moves
(Laurent's forest isomorphism). We deduce from this an equational theory
characterizing isomorphisms of types in our language. We show however that
Laurent's conjecture does not hold on infinitely branching arenas, yielding new
non-trivial type isomorphisms in a variant of our language with natural
numbers.
Pseudo-finite hard instances for a student-teacher game with a Nisan-Wigderson generator
Authors: Krajíček Jan
Published: November 2013

For an NP intersect coNP function g of the Nisan-Wigderson type and a string
b outside its range we consider a two player game on a common input a to the
function. One player, a computationally limited Student, tries to find a bit of
g(a) that differs from the corresponding bit of b. He can query a
computationally unlimited Teacher for the witnesses of the values of constantly
many bits of g(a). The Student computes the queries from a and from Teacher's
answers to his previous queries. It was proved by Krajicek (2011) that if g is
based on a hard bit of a one-way permutation then no Student computed by a
polynomial size circuit can succeed on all a. In this paper we give a lower
bound on the number of inputs a any such Student must fail on. Using that we
show that there is a pseudo-finite set of hard instances on which all uniform
students must fail. The hard-core set is defined in a non-standard model of
true arithmetic and has applications in a forcing construction relevant to
proof complexity.
Efficient Parallel Path Checking for Linear-Time Temporal Logic With Past and Bounds
Authors: Kuhtz Lars , Finkbeiner Bernd
Published: November 2013

Path checking, the special case of the model checking problem where the model
under consideration is a single path, plays an important role in monitoring,
testing, and verification. We prove that for linear-time temporal logic (LTL),
path checking can be efficiently parallelized. In addition to the core logic,
we consider the extensions of LTL with bounded-future (BLTL) and past-time
(LTL+Past) operators. Even though both extensions improve the succinctness of
the logic exponentially, path checking remains efficiently parallelizable: Our
algorithm for LTL, LTL+Past, and BLTL+Past is in AC^1(logDCFL) \subseteq NC.
Linear Dependent Types and Relative Completeness
Authors: Lago Ugo Dal , Gaboardi Marco
Published: November 2013

A system of linear dependent types for the lambda calculus with full
higher-order recursion, called dlPCF, is introduced and proved sound and
relatively complete. Completeness holds in a strong sense: dlPCF is not only
able to precisely capture the functional behaviour of PCF programs (i.e. how
the output relates to the input) but also some of their intensional properties,
namely the complexity of evaluating them with Krivine's Machine. dlPCF is
designed around dependent types and linear logic and is parametrized on the
underlying language of index terms, which can be tuned so as to sacrifice
completeness for tractability.
On computable approximations of Landau's constant
Authors: Rettinger Robert
Published: November 2013

We present an algorithm which computes the Landau constant up to any given
precision.
The Structure of Differential Invariants and Differential Cut Elimination
Authors: Platzer Andre
Published: November 2013

The biggest challenge in hybrid systems verification is the handling of
differential equations. Because computable closed-form solutions only exist for
very simple differential equations, proof certificates have been proposed for
more scalable verification. Search procedures for these proof certificates are
still rather ad-hoc, though, because the problem structure is only understood
poorly. We investigate differential invariants, which define an induction
principle for differential equations and which can be checked for invariance
along a differential equation just by using their differential structure,
without having to solve them. We study the structural properties of
differential invariants. To analyze trade-offs for proof search complexity, we
identify more than a dozen relations between several classes of differential
invariants and compare their deductive power. As our main results, we analyze
the deductive power of differential cuts and the deductive power of
differential invariants with auxiliary differential variables. We refute the
differential cut elimination hypothesis and show that, unlike standard cuts,
differential cuts are fundamental proof principles that strictly increase the
deductive power. We also prove that the deductive power increases further when
adding auxiliary differential variables to the dynamics.
On streams that are finitely red
Authors: Bezem Marc , Nakata Keiko , Uustalu Tarmo
Published: November 2013

Mixing induction and coinduction, we study alternative definitions of streams
being finitely red. We organize our definitions into a hierarchy including also
some well-known alternatives in intuitionistic analysis. The hierarchy
collapses classically, but is intuitionistically of strictly decreasing
strength. We characterize the differences in strength in a precise way by weak
instances of the Law of Excluded Middle.