The taxonomic relationship of Rhinosporidium seeberi with other organisms remained controversial for over a century. Recently, molecular studies have shown R. seeberi to be a protistal microbe in the newly described class Mesomycetozoea at the animal-fungal boundary. Phylogenetic analyses of R. seeberi using 18S small-subunit (SSU) rRNA genes from several hosts suggested Rhinosporidium as a monotypic genus. To test this hypothesis, the internal transcribed spacer 1 (ITS1), 5.8S, and ITS2 from eight humans, two swans, and a dog with rhinosporidiosis were sequenced. The ITS regions were amplified by PCR using a primer designed from a unique region of R. seeberi's 18S SSU rRNA genes in combination with the ITS4 universal primer. In addition, the universal ITS4 and ITS5 primers were also used. R. seeberi's ITS sequences showed differences in the numbers of nucleotides among strains. For instance, the eight human ITS sequences were uniformly similar with only a few mismatches and similar to 1,060 bp long. In contrast, sequences from one of the swans and the dog were 1,356 bp and similar to 1,147 bp long, respectively. Clustal analysis of all of the ITS sequences showed multiple 50- to 60-bp gaps and several mismatches among them. Parsimony analysis placed the Rhinosporidium ITS sequences in three well-supported sister groups according to the hosts' identities. This analysis strongly suggests that the genus Rhinosporidium may possess multiple host-specific strains. No correlation was found between this finding and the phenotypic features of R. seeberi in the studied samples.
A general approach to the nonexpansive M band decomposition of finite length signals is presented. The technique is based on linear signal extensions and can be applied to all types of linear- and nonlinear phase M-band perfect-reconstruction filter banks. The signal expansion is described by a linear transformation on the input signal, and the extended subband samples can be easily found using simple matrix computations.
Where a-Si:H pin devices are concerned, one of the main obstacles regarding improved performance is device stability, usually attributed to adverse behaviour at various interfaces within the device. Several attempts have been made to overcome this problem, such as the use of blocking layers at the interfaces. Although these have led to some improvements in device performance, most of the problems associated with device stability remain. This is mainly due to the defects at the interfaces, since the blocking layers (silicon alloys with carbon, nitrogen or oxygen) usually have a high density of bulk states, in comparison to intrinsic a-Si:H films. In this paper, we present a method that seems to be capable of improving device stability. It consists of performing a controlled removal of oxide interlayers at the interfaces, by an appropriate etching process. This enables the production of highly smoothed interfaces, and reduces possible cross-contamination of the i-layer from the adjacent doped layers. This amounts to a new design of typical pin devices, in which thin absorber layers are placed at the p/i and i/n interfaces. Their purpose is to trap most of the impurity atoms diffused from the doped layers, after which they are removed by appropriate etching. The fabrication of the absorbers (sacrificial layers), the nature of the etching and the tailoring of the defect profile at the interfaces will be discussed, including the performance exhibited by the resulting devices
This study presents a seismic vulnerability and risk assessment of the residential building stock in Costa Rica. It proposes a new exposure model using housing census data, public construction statistics, and private construction information to quantify and characterize the residential building portfolio. A complete vulnerability catalogue is established by developing fragility functions for the most common building classes and combining them with existing models derived for risk assessment in South America. An existing probabilistic seismic hazard model was implemented within the OpenQuake-engine, and complemented with a simplified site model to account for site effects. Earthquake risk assessment is achieved by means of a probabilistic event-based analysis, which allowed the estimation of several risk metrics. These include average annualized losses at a national scale, disaggregated per building class and administrative regions. The probable maximum losses and exceedance probability curves were generated using a stochastic event set with 100,000years of events per logic tree branch.
The transducer consists of a semiconductor device based on two stacked -i-n heterostructures that were designed to detect the emissions of the fluorescence resonance energy transfer between fluorophores in the cyan (470 nm) and yellow (588 nm) range of the spectrum. This research represents a preliminary study on the use of such wavelength-sensitive devices as photodetectors for this kind of application. The device was characterized through optoelectronic measurements concerning spectral response measurements under different electrical and optical biasing conditions. To simulate the fluorescence resonance energy transfer (FRET) pairs, a chromatic time-dependent combination of cyan and yellow wavelengths was applied to the device. The generated photocurrent was measured under reverse and forward bias to read out the output photocurrent signal. A different wavelength-biasing light was also superimposed. Results show that under reverse bias, the photocurrent signal presents four separate levels, each one assigned to the different wavelength combinations of the FRET pairs. If a blue background is superimposed, the yellow channel is enhanced and the cyan suppressed, while under red irradiation, the opposite behavior occurs. So, under suitable biasing light, the transducer is able to detect separately the cyan and yellow fluorescence pairs. An electrical model, supported by a numerical simulation, supports the transduction mechanism of the device.
A new and efficient video coding algorithm is described. It is based on the wavelet decomposition of video signals using orthonormal and biorthogonal filter banks. The motion compensated error images are represented by variable size blocks. To improve the coding efficiency and to minimize the border effects associated to the wavelet transform, a new quadtree based merging algorithm was developed. The results of two coding scenarios are discussed.
Alves, A. M. Brites
This work presents experimental observations on the permeation of multi-ionic solutions through a commercial DESAL-HL nanofiltration membrane. Two types of mixed-salt solutions have been analysed with a common co-ion (NaCl + Na(2)SO(4)) and with a common counter-ion ((NaCl + MgCl(2))). The NaCl concentrations have been similar to those of seawater with divalent ions with lower concentrations up to a tenth of that of the monovalent salt. In this study. SEDE-VCh model that includes the variation of the charge inside the membrane pores has been used to model the system and structural, electrical and dielectrical membrane parameters for such systems have been obtained. We show that accurate enough predictions can be achieved for the retention of monovalent ions in the presence of counter or co-ion divalent ions from the single NaCl salt results. While correct predictions for the retention of the divalent ions require membrane charges and dielectric constants dependent of the ionic composition of the solutions filtered. (C) 2011 Elsevier B.V. All rights reserved.
In nanofiltration it is important for predictive purposes to obtain retentions and/or reflection coefficients from known sizes of the pores and the molecules of uncharged solutes. This correlation is also needed in order to model the mass transport of salts or other charged species. To complete these model and predictive needs, the hindrance factors have to be correlated with the ratio between the pore and the molecule sizes, lambda. There are several correlations proposed in the literature. Moreover, the effect of the applied pressure was not accounted for in these correlations until recent revisions of the transport model. In some cases the action of the pore-wall friction has been also neglected. Here we make a revision of these different assumptions on the hindrance factors, we discuss their effect on the transport and we show some conditions that a correct correlation should accomplish. It is shown that it is important to consider both the pressure and the pore-wall friction because the corresponding terms have important contributions to both retention and reflection. It is, nevertheless, less relevant an accurate choice of a relationship for the pore hindrance factors in terms of lambda, as far as, both retention and reflection are mainly controlled by partitioning in the ranges where the different proposed correlations differ, what leads to the same transport predictions. In any case a theoretically correct correlation can be chosen attending to the conditions that the pore reflection must accomplish.
Photoacoustic generation is an attractive alternative to generate ultrasound due to its broad bandwidth and high frequency capabilities. However, the challenges in low generation efficiency need to be addressed. In order to address this issue, a one-pot synthesized polydimethylsiloxane-gold nanoparticle (PDMS/Auu NP) nanocomposite was utilized to generate ultrasonic pulses excited by a nanosecond laser. The enhanced efficiency of the photoacoustic signal was investigated by varying the concentration and the thickness of the nanocomposite film. The optimal peak-to-peak amplitude of the acoustic signal was observed to be 189.49 kPa under the laser energy density of 13 mJ/cm 2 at 1.8 mm away from the nanocomposite film, when the thickness and the concentration of the film were 450 mum and 1.79 wt. %, respectively. Furthermore, the efficiency of the photoacoustic generation was increased 3 orders of magnitude compared to the aluminum thin film. The results indicate that high photoacoustic generation efficiency could be achieved through the PDMS/Au NPs nanocomposite.