Pattern Formation on Trees

Networks having the geometry and the connectivity of trees are considered as the spatial support of spatiotemporal dynamical processes. A tree is characterized by two parameters: its ramification and its depth. The local dynamics at the nodes of a tree is described by a nonlinear map, given rise to a coupled map lattice system. The coupling is expressed by a matrix whose eigenvectors constitute a basis on which spatial patterns on trees can be expressed by linear combination. The spectrum of eigenvalues of the coupling matrix exhibit a nonuniform distribution which manifest itself in the bifurcation structure of the spatially synchronized modes. These models may describe reaction-diffusion processes and several other phenomena occurring on heterogeneous media with hierarchical structure.Comment: Submitted to Phys. Rev. E, 15 pages, 9 fig

Phase separation in coupled chaotic maps on fractal networks

The phase ordering dynamics of coupled chaotic maps on fractal networks are investigated. The statistical properties of the systems are characterized by means of the persistence probability of equivalent spin variables that define the phases. The persistence saturates and phase domains freeze for all values of the coupling parameter as a consequence of the fractal structure of the networks, in contrast to the phase transition behavior previously observed in regular Euclidean lattices. Several discontinuities and other features found in the saturation persistence curve as a function of the coupling are explained in terms of changes of stability of local phase configurations on the fractals.Comment: (4 pages, 4 Figs, Submitted to PRE

A SspI PCR-RFLP detecting a silent allele at the goat CSN2 locus

The comparison between the cDNA sequence obtained and the published sequences of the goat CSN2 alleles showed a new single nucleotide polymorphism (SNP) (transition C-T) at the 180th nucleotide of the ninth exon. This mutation, which took place at 124 nt from the polyadenylation site, identifies a silent allele at the CSN2 locus named CSN2 A1. Since the 9th exon C-T transition creates a SspI endonuclease restriction site, the SspI digestion of a PCR product of 360 bp spanning the 9th exon and flanking regions, would allow carriers for the presence of thymine to be identified. The allelic frequency of the CSN2 A1 allele, determined in 170 goats belonging to an undefined genetic type reared in the province of Naples (Italy), was 0.23 It has been observed that the sequences in the 3’ untranslated regions (UTR), proximal to the polyadenylation site, can affect the mechanism of mRNA deadenylation and degradation. Therefore, it is reasonable to hypothesize that the C-T transition might, directly or indirectly, influence the stability of the mRNA and, consequently, the amount of protein produced

The influence of solid retention time on IFAS-MBR systems: Assessment of nitrous oxide emission

The aim of the present study was to investigate the nitrous oxide (N2O) emissions from a moving bed based Integrated Fixed Film Activated Sludge (IFAS) - membrane bioreactor (MBR) pilot plant, designed according to the University of Cape Town (UCT) layout. The experimental campaign had a duration of 110 days and was characterized by three different sludge retention time (SRT) values (\ue2\u88\u9e, 30 d and 15 d). Results highlighted that N2O concentrations decreased when the biofilm concentrations increased within the aerobic reactor. Results have shown an increase of N2O with the decrease of SRT. Specifically, an increase of N2O-N emission factor occurred with the decrease of the SRT (0.13%, 0.21% and 0.76% of influent nitrogen for SRT = \ue2\u88\u9e, SRT = 30 d and SRT = 15 d, respectively). Moreover, the MBR tank resulted the key emission source (up to 70% of the total N2O emission during SRT = \ue2\u88\u9e period) whereas the highest N2O production occurred in the anoxic reactor. Moreover, N2O concentrations measured in the permeate flow were not negligible, thus highlighting its potential detrimental contribution for the receiving water body. The role of each plant reactor as N2O-N producer/consumer varies with the SRT variation, indeed the aerobic reactor was a N2O consumer at SRT = \ue2\u88\u9e and a producer at SRT = 30 d

Sequential batch membrane bio-reactor for wastewater treatment: The effect of increased salinity

In this work, a sequential batch membrane bioreactor pilot plant is investigated to analyze the effect of a gradual increase in salinity on carbon and nutrient removal, membrane fouling and biomass kinetic parameters. The salinity was increased by 2 g NaCl L-1 per week up to 10 g NaCl L-1. The total COD removal efficiency was quite high (93%) throughout the experiment. A gradual biomass acclimation to the salinity level was observed during the experiment, highlighting the good recovery capabilities of the system. Nitrification was also influenced by the increase in salinity, with a slight decrease in nitrification efficiency (the lowest value was obtained at 10 g NaCl L-1 due to lower nitrifier activity). Irreversible cake deposition was the predominant fouling mechanism observed during the experiment. Respirometric tests exhibited a stress effect due to salinity, with a reduction in the respiration rates observed (from 8.85 mgO2 L-1 h-1 to 4 mgO2 L-1 h-1)

Periodic Neural Activity Induced by Network Complexity

We study a model for neural activity on the small-world topology of Watts and Strogatz and on the scale-free topology of Barab\'asi and Albert. We find that the topology of the network connections may spontaneously induce periodic neural activity, contrasting with chaotic neural activities exhibited by regular topologies. Periodic activity exists only for relatively small networks and occurs with higher probability when the rewiring probability is larger. The average length of the periods increases with the square root of the network size.Comment: 4 pages, 5 figure

Molecular cloning, promoter analysis and SNP identification of Italian Nicastrese and Saanen lactoferrin gene

Lactoferrin (Lf) is an iron-binding glycoprotein found in exocrine secretions including milk. High levels of lactoferrin may have a role in the prevention of microbial infection of the mammary gland. In this report we sequenced and characterized goat lactoferrin cDNA and its promoter region in two different breeds of goat. The complete cDNA comprised 2356 nucleotides, including 38bp at the 5'-UTR and 194bp at the 3'-UTR. The open reading frame is 2127bp long and it encodes a mature protein of 689 aminoacids. A total of 19 nucleotide differences, 11 of them being responsible for 8 aminoacid changes, were identified through the comparison with French, Korean and Tibetan goat lactoferrin cDNAs. About 1700bp of the lactoferrin gene promoter were sequenced. Sequence analysis revealed a non-canonical TATA box, multiple SP1/GC elements, and other putative binding sites for transcription factors, such as NF-kappaB, STAT3 and AP2. Two SNPs were identified, one of which would seem to create a new putative AP2 consensus sequence. The presence of an additional AP2 binding site could be associated with quantitative differences of such protein fraction, which could enhance all the activities related to such protein, and improve mammary gland defence against bacterial infections

Greenhouse gas emissions from wastewater treatment plants on a plantwide scale: Sensitivity and uncertainty analysis

This paper presents the sensitivity and uncertainty analysis of a mathematical model for greenhouse gas emission (GHG) and energy consumption assessment in wastewater treatment plants. A sensitivity analysis was carried out (using two different methods) to determine which model factors have the greatest effect on the predicted values of the GHG production. Further, an uncertainty analysis was carried out to quantify the uncertainty of the key model outputs, such as carbon dioxide production from activated sludge treatment. The results show that influent fractionation factors, which characterize influent composition, have an important role on direct and indirect GHGs production and emission. Moreover, model factors related to the aerobic biomass growth show a relevant influence on GHGs in terms of emission from off-site power generation (mCO2eq,PG). Further, model factors related to the autotrophic biomass growth were found to strongly interact with other factors especially in modeling mCO2eq,PG. Finally, nitrous oxide (N2O) emission associated with the effluent has the highest uncertainty, suggesting the need for a mechanistic model for N2O production in biological treatment

Comparison between two MBR pilot plants treating synthetic shipboard slops: the effect of salinity increase on biological performance, biomass activity and fouling tendency

The paper reports the main results of an experimental campaign carried out on two bench scale pilot plants for the treatment of synthetic shipboard slops. In particular, two membrane bioreactors (MBRs) with submerged configuration were analyzed. One MBR pilot plant (namely, Line A) was fed with synthetic shipboard slop and was subjected to a gradual increase of salinity. Conversely, the second MBR pilot plant (namely, Line B) was fed with the same synthetic shipboard slop but without salt addition, therefore operating as a \ue2\u80\u9ccontrol\ue2\u80\u9d unit. Organic carbon, hydrocarbons and ammonium removal, kinetic constants, extracellular polymeric substances (EPSs) production and membranes fouling rates have been assessed. The observed results highlighted a stress effect exerted by salinity on the biological performances, with lower removal efficiencies in the Line A compared to Line B. Significant releases of soluble EPS in Line A promoted an increase of the resistance related to particle deposition into membrane pores (pore fouling tendency), likely due to a worsening of the mixed liquor features. Such a condition enhanced the reduction of the \ue2\u80\u9cpre-filter\ue2\u80\u9d effect of the cake layer

Treatment of oily wastewater with membrane bioreactor systems

The aim of the present work was to investigate the behavior of a membrane bioreactor (MBR) system for the treatment of oily wastewater. A bench scale MBR was fed with synthetic wastewater containing diesel fuel. Organic carbon, hydrocarbon and ammonium removal, kinetic constants, extracellular polymeric substances production, and membrane fouling rates were monitored. The MBR plant was operated for more than 200 days, and the results highlighted good carbon removal and nitrification, suggesting a sort of biomass adaptation to hydrocarbons. Membrane fouling analysis showed an increase in total resistance, likely due to hydrocarbons, which caused an irreversible fouling (pore blocking) mainly due to oil deposition