SAS Method Research Articles

Characterization of growth traits of Greenland and Silver coypus under captivity conditions

Brody, Gompertz, Logistic, Richards and von Bertalanffy functions were compared as descriptors of growth in 319 coypus (Myocastor coypus) of Greenland and Silver varieties, from birth to 10–19 months of age. Several criteria were considered for the selection of the model: (a) bias in the asymptotic weight; (b) bias in birth weight; (c) error sum of squares; (d) error mean squares weighted by the number of animals converging in all functions; (e) determination coefficient. To adjust the curves NLIN procedure from SAS and iterative method of Marquardt were applied. A mixed model was used to analyse the parameters of the selected growth curve (asymptotic weight, A; constant of integration, B; and maturation rate, k) which included effects of farm, variety, sex, sire within farm and variety, reproductive status within sex, birth season and first order interactions. The effect of sire was considered as random. The von Bertalanffy function was selected and mean values for the parameters of this function were 8016 g and 0·008 g/g per day, for A and k respectively. There were differences in the estimated parameters between sexes; males had larger values of A and k than females.Weights at fixed ages (birth, weaning, 6–7 months) were analysed, as well as the final recorded weight and average postweaning gain. The model of analysis was similar to the previous one. There were no differences between varieties. Significant differences between sexes for almost all studied traits were detected. With age, weight difference between males and females increased. At 6 months of age, males were 37% heavier than females. Male average daily gain was higher than that of females, sexual dimorphism being evident in all analysed traits.

Oligosaccharide Synthesis by Affinity Separation Based on Molecular Recognition between Podand Ether and Ammonium Ion

We previously reported a new synthetic methodology termed 'synthesis based on affinity separation' (SAS) in which the desired tagged compound was separated from the reaction mixture by solid-phase extraction using specific molecular recognition of the tag. The interaction between a crown ether tag and polymer-supported ammonium ion was initially employed for SAS. In the present study, a new SAS method using a podand-type tag, a pseudo-benzo-31-crown-10 structure, was elaborated for oligosaccharide synthesis. The podand tag was much easier to synthesize than the corresponding crown ether. The podand moiety was attached to the monosaccharide residue via appropriate linkers. After glycosylation of the tagged monosaccharide with a glycosyl donor, the reaction mixture was subjected to the affinity separation. The desired compounds possessing the podand tag were effectively separated by the affinity between the podand and the ammonium ion. Continuous flow synthesis by integration of a microreactor and the present SAS system was applied for high throughput oligosaccharide synthesis.

Use of two spatially explicit models to determine the effect of injury geometry on natural resource recovery

Abstract Disturbance to sessile communities has been evaluated in a wide variety of terrestrial and marine settings, but, to our knowledge, recovery has not explicitly considered the effects of injury shape, except in an exploratory fashion. Therefore, we have developed a simple, but spatially explicit relationship between the geometry of a disturbance and the recovery rate in the context of natural resource damage assessment. Here, grounding of motor vessels in shoalgrass (Halodule wrightii), manatee grass (Syringodium filiforme), and turtlegrass (Thalassia testudinum) habitats results in a variety of injury shapes whose recovery must be evaluated to assign penalties and restoration costs to the party responsible. We developed two spatially explicit, cellular automata modelling techniques to evaluate injury recovery trajectory. Techniques in both SAS® and ArcINFO® were developed and applied to injuries of varying perimeter but fixed area. The SAS method utilized either a simple Boolean or probabalistic interrogation of the status of adjacent pixels using the matrix language component of the software. ArcINFO utilized a cost/distance module to evaluate proximity of unfilled to filled (colonized) pixels and then applied a decision rule that governed conversion from unfilled to a filled state. As expected, the greater the perimeter/area ratio, the faster the recovery; and modelling approaches yielded almost identical results. A case study involving ∼1200 m2 of almost monotypic T. testudinum revealed that both models predicted that 100% recovery of above‐ground components of the injury would not occur for approximately 60 years. This model is now being used routinely in the assessment of vessel groundings in seagrass beds within the Florida Keys National Marine Sanctuary and has been used successfully by the Government to prevail in US Federal Court challenges. Both methods have substantial, untapped capabilities to explore the effect of numerous ecological effects on the processes influencing recovery from disturbance. Published in 2004 by John Wiley & Sons, Ltd.

Potential of mean force calculation of solute molecules in water by a modified solvent-accessible surface method

We propose an empirical method for evaluating the potential of . mean force pmf of solute molecules in water by modifying the solvent- . accessible surface SAS method described by Eisenberg et al. We re-evaluated the SAS energy for each united atom composing the solute. We took into account the energy required to generate a void between adjacent solute molecules and the Coulombic interactions between atom-centered point charges of solute molecules containing C, O, P, K q ,N a q , and Cl y atoms in water. The modified SAS method well reproduced the various pmfs given by MD calculations or the integral equation method. The large activation energy of K q )18-crown-6 complexation can be explained mostly by the void energy. The computational time required for the modified SAS method is approximately three to four orders of magnitude less than that by MD calculations. Q 1997 John Wiley & Sons, Inc. J Comput Chem 18: 1656)1663, 1997

Formation of monolayer of molybdena over alumina by unconventional slurry impregnation or solvent assisted spreading method

Alumina supported molybdenum catalysts with variable loading and support particle size were prepared by the unconventional equilibrium adsorption in slurry MoO 3/water. The method can be named either slurry impregnation method, SIM (when compared with impregnation in ammonium molybdate solution) or solvent assisted spreading, SAS (when compared with thermal spreading of MoO 3). The maximum saturated adsorption loading achieved with alumina of surface area 172 m 2 g −1 and particle size 0.16–0.32 mm was 14.4 wt% MoO 3. No other crystalline phase beside γ-Al 2O 3 was found in XRD spectra of the catalysts. The XPS surface ratio Mo Al in oxide form and the thiophene hydrodesulphurization activity in sulphide form increased linearly with the overall composition up to saturated adsorption loading. The hydrodesulphurization activity of the SIM SAS catalysts of corresponding loading was comparable or better than the activity of conventional commercial MoO 3 Al 2O 3 catalyst. All this indicated that the monolayer type catalysts are obtained by SIM SAS method. The electron probe micro analysis of the SIM SAS catalyst prepared from extrudates (1.5 mm) confirmed uniform cross sectional distribution of molybdena. This proved that the SIM SAS method can be used not only for small support particles but also for usual extrudates or tablets. The relation and advantage of the SIM SAS method as compared with other methods of preparation of monolayer molybdena catalysts were discussed.

Reproduction of the Potential of Mean Force by a Modified Solvent-Accessible Surface Method

Calculation of the potential of mean force of solute molecules in a solvent is a basic task for understanding many phenomena in solutions. Protein−protein interactions in water are, however, far from fully understood even with the latest supercomputers. In this paper we propose an empirical method to obtain the potential of mean force of solute molecules by means of a modified solvent-accessible-surface (modified SAS) method which is based on the molecular dynamics simulations. We took into account the energy contribution of generating an excluded volume between adjacent solute molecules in the SAS method proposed by Eisenberg et al. The proposed method was examined on the potentials of mean force (pmf's) of methane−methane, octane−octane, carbon−oxygen (methane−water) and oxygen−oxygen (water−water) in water and successfully reproduced the pmf's. This method is basically applicable to general molecular interactions, such as protein−protein interactions in water.

Phase-derivative imaging. II: Effects of beam diffraction and scatterer density.

The potential of using the phase derivative (PD) of the radio-frequency echograms for producing 2-dimensional grey scale images was further investigated. The PD images were produced by five different algorithms, which according to the results described in the companion paper yield PD images dominated by the amplitude (envelope, ENV), mixed PD-AM images and pure PD images. These images are termed according to their algorithms: ZCS, zero crossing counter with squelch; ASS, analytic signal with squelch; ASW, analytic signal with Wiener kernel; UNP, unwrapped phase; and SAS, smoothed analytic signal. The rf data were obtained from simulations and from experiments with a tissue mimicking phantom. PD images were analysed by calculation of the first and second order grey level statistics: mean level, signal-to-noise ratio (SNR) and the full width at half maximum (FWHM) of the autocovariance functions (ACVF). These parameters were systematically investigated for a range of depths with respect to the transducer and a range of scatterer densities of the insonated medium. The UNP and SAS images do not suffer much from the diffraction effect but do not display much information about the scatterer density either. The ASW and ASS images qualitatively display beam diffraction effects similar to those of the AM images, with the exception of the mean value which is at the minimum in the focus, where the AM yields a sharp maximum at that depth. The mean and the SNR of the ASW and ASS images increase with increasing scatterer density and saturate at a density of 5000 cm-3. The mean value of the envelope, however, displays a square root dependency over the whole range. The axial and lateral FWHM of the ACVF of the UNP and SAS methods are not significantly dependent on the scatterer density and decrease with increasing density for the ASW and ASS images, as was observed in the envelope images. It may be concluded that ASW and ASS methods produce PD grey scale images which are equally well suited for the diagnosis of diffuse diseases of parenchymal tissues as conventional AM images. The smaller "speckle" size of the ASW images might be advantageous, for the detection of focal lesions, but the lesion contrast is found to be much lower than for the ENV.

Phase-derivative imaging II: Effects of beam diffraction and scatterer density

The potential of using the phase derivative (PD) of the radio-frequency echograms for producing 2-dimensional grey scale images was further investigated. The PD images were produced by five different algorithms, which according to the results described in the companion paper yield PD images dominated by the amplitude (envelope, ENV), mixed PD-AM images and pure PD images. These images are termed according to their algorithms: ZCS, zero crossing counter with squelch; ASS, analytic signal with squelch; ASW, analytic signal with Wiener kernel; UNP, unwrapped phase; and SAS, smoothed analytic signal. The rf data were obtained from simulations and from experiments with a tissue mimicking phantom. PD images were analysed by calculation of the first and second order grey level statistics: mean level, signal-to-noise ratio (SNR) and the full width at half maximum (FWHM) of the autocovariance functions (ACVF). These parameters were systematically investigated for a range of depths with respect to the transducer and a range of scatterer densities of the insonated medium. The UNP and SAS images do not suffer much from the diffraction effect but do not display much information about the scatterer density either. The ASW and ASS images qualitatively display beam diffraction effects similar to those of the AM images, with the exception of the mean value which is at the minimum in the focus, where the AM yields a sharp maximum at that depth. The mean and the SNR of the ASW and ASS images increase with increasing scatterer density and saturate at a density of 5000 cm −3. The mean value of the envelope, however, displays a square root dependency over the whole range. The axial and lateral FWHM of the ACVF of the UNP and SAS methods are not significantly dependent on the scatterer density and decrease with increasing density for the ASW and ASS images, as was observed in the envelope images. It may be concluded that ASW and ASS methods produce PD grey scale images which are equally well suited for the diagnosis of diffuse diseases of parenchymal tissues as conventional AM images. The smaller “speckle” size of the ASW images might be advantageous, for the detection of focal lesions, but the lesion contrast is found to be much lower than for the ENV.

Déterminations des températures et des pressions par spectrométrie Raman au cours de la CVT du nickel

Nickel CVT, based on the following chemical equilibrium: Ni (s) + 4CO (g) ⇌ Ni(CO) 4(g), has been studied by Raman spectroscopy. The temperature of the gaseous mixture can be calculated from the experimental intensities of CO rotational Raman-Stokes lines. The simulation of CO spectrum has been made from the theoretical intensities of lines convoluted with functions taking account of the incident band shape (Gaussian function) slit geometry (apparatus function). Simulated and experimental spectra are in a good agreement and the calculated temperature is found with a precision of one Celsius degree compared with the temperature measured at 1/10°C precisely. From the Ni(CO) 4 vibration V S (Al) at 370.6 cm −1 available both in Stokes and anti-Stokes fields, we have another method of temperature calculation (SAS method). At a known temperature, the same vibration can be used to compute the partial pressure of Ni(CO) 4. Results obtained are compared with those directly measured with a tensimeter. The temperature and the pressure respectively determined from the CO rotation lines and the NiC symmetric stretching vibration at 370.6 cm −1 permit us to follow the nickel CVT in a transparent furnace (SnO 2 technology).