A method for setting the size of plant conservation target areas

Realistic time frames in which management decisions are made often preclude the completion of the detailed analyses necessary for conservation planning. Under these circumstances, efficient alternatives may assist in approximating the results of more thorough studies that require extensive resources and time. We outline a set of concepts and formulas that may be used in lieu of detailed population viability analyses and habitat modeling exercises to estimate the protected areas required to provide desirable conservation outcomes for a suite of threatened plant species. We used expert judgment of parameters and assessment of a population size that results in a specified quasiextinction risk based on simple dynamic models The area required to support a population of this size is adjusted to take into account deterministic and stochastic human influences, including small-scale disturbance deterministic trends such as habitat loss, and changes in population density through processes such as predation and competition. We set targets for different disturbance regimes and geographic regions. We applied our methods to Banksia cuneata, Boronia keysii, and Parsonsia dorrigoensis, resulting in target areas for conservation of 1102, 733, and 1084 ha, respectively. These results provide guidance on target areas and priorities for conservation strategies.

Determining complicated winding patterns for shim coils using stream functions and the target-field method

In a magnetic resonance imaging equipment, gradient and shim coils are needed to produce a spatially varying magnetic field throughout the sample being imaged. Such coils consist of turns of wire wound on the surface of a cylindrical tube. Shim coils in particular, must sometimes be designed to produce complicated magnetic fields to correct for impurities. Streamline patterns for shim coils are much more complicated than those for gradient coils, In this work we present a detailed analysis of streamline methods and their application to shim coil design, A method is presented for determining the winding patterns to generate these complicated fields. (C) 2002 John Wiley & Sons, Inc.

A method for the design of MRI radiofrequency coils based on triangular and pulse basis functions

This paper presents a numerical technique for the design of an RF coil for asymmetric magnetic resonance imaging (MRI) systems. The formulation is based on an inverse approach where the cylindrical surface currents are expressed in terms of a combination of sub-domain basis functions: triangular and pulse functions. With the homogeneous transverse magnetic field specified in a spherical region, a functional method is applied to obtain the unknown current coefficients. The current distribution is then transformed to a conductor pattern by use of a stream function technique. Preliminary MR images acquired using a prototype RF coil are presented and validate the design method. (C) 2002 Elsevier Science B.V. All rights reserved.

NMR shim coil design utilising a rapid spherical harmonic calculation method

A rapid spherical harmonic calculation method is used for the design of Nuclear Magnetic Resonance shim coils. The aim is to design each shim such that it generates a field described purely by a single spherical harmonic. By applying simulated annealing techniques, coil arrangements are produced through the optimal positioning of current-carrying circular arc conductors of rectangular cross-section. This involves minimizing the undesirable harmonies in relation to a target harmonic. The design method is flexible enough to be applied for the production of coil arrangements that generate fields consisting significantly of either zonal or tesseral harmonics. Results are presented for several coil designs which generate tesseral harmonics of degree one.

Methods for prediction of peptide binding to MHC molecules: A comparative study

Background: A variety of methods for prediction of peptide binding to major histocompatibility complex (MHC) have been proposed. These methods are based on binding motifs, binding matrices, hidden Markov models (HMM), or artificial neural networks (ANN). There has been little prior work on the comparative analysis of these methods. Materials and Methods: We performed a comparison of the performance of six methods applied to the prediction of two human MHC class I molecules, including binding matrices and motifs, ANNs, and HMMs. Results: The selection of the optimal prediction method depends on the amount of available data (the number of peptides of known binding affinity to the MHC molecule of interest), the biases in the data set and the intended purpose of the prediction (screening of a single protein versus mass screening). When little or no peptide data are available, binding motifs are the most useful alternative to random guessing or use of a complete overlapping set of peptides for selection of candidate binders. As the number of known peptide binders increases, binding matrices and HMM become more useful predictors. ANN and HMM are the predictive methods of choice for MHC alleles with more than 100 known binding peptides. Conclusion: The ability of bioinformatic methods to reliably predict MHC binding peptides, and thereby potential T-cell epitopes, has major implications for clinical immunology, particularly in the area of vaccine design.

Content and context of monocular regions determine perceived depth in random dot, unpaired background and phantom stereograms

Perceived depth was measured for three-types of stereograms with the colour/texture of half-occluded (monocular) regions either similar to or dissimilar to that of binocular regions or background. In a two-panel random dot stereogram the monocular region was filled with texture either similar or different to the far panel or left blank. In unpaired background stereograms the monocular region either matched the background or was different in colour or texture and in phantom stereograms the monocular region matched the partially occluded object or was a different colour or texture. In all three cases depth was considerably impaired when the monocular texture did not match either the background or the more distant surface. The content and context of monocular regions as well as their position are important in determining their role as occlusion cues and thus in three-dimensional layout. We compare coincidence and accidental view accounts of these effects. (C) 2002 Elsevier Science Ltd. All rights reserved.

Genetic algorithms for design of liquid retaining structure

In this paper, genetic algorithm (GA) is applied to the optimum design of reinforced concrete liquid retaining structures, which comprise three discrete design variables, including slab thickness, reinforcement diameter and reinforcement spacing. GA, being a search technique based on the mechanics of natural genetics, couples a Darwinian survival-of-the-fittest principle with a random yet structured information exchange amongst a population of artificial chromosomes. As a first step, a penalty-based strategy is entailed to transform the constrained design problem into an unconstrained problem, which is appropriate for GA application. A numerical example is then used to demonstrate strength and capability of the GA in this domain problem. It is shown that, only after the exploration of a minute portion of the search space, near-optimal solutions are obtained at an extremely converging speed. The method can be extended to application of even more complex optimization problems in other domains.

Is your vision consistent? A method for checking, based on scenario concepts

Common sense tells us that the future is an essential element in any strategy. In addition, there is a good deal of literature on scenario planning, which is an important tool in considering the future in terms of strategy. However, in many organizations there is serious resistance to the development of scenarios, and they are not broadly implemented by companies. But even organizations that do not rely heavily on the development of scenarios do, in fact, construct visions to guide their strategies. But it might be asked, what happens when this vision is not consistent with the future? To address this problem, the present article proposes a method for checking the content and consistency of an organization`s vision of the future, no matter how it was conceived. The proposed method is grounded on theoretical concepts from the field of future studies, which are described in this article. This study was motivated by the search for developing new ways of improving and using scenario techniques as a method for making strategic decisions. The method was then tested on a company in the field of information technology in order to check its operational feasibility. The test showed that the proposed method is, in fact, operationally feasible and was capable of analyzing the vision of the company being studied, indicating both its shortcomings and points of inconsistency. (C) 2007 Elsevier Ltd. All rights reserved.

Modelling the Distribution of Ischaemic Stroke-Specific Survival Time Using an EM-based Mixture Approach with Random Effects Adjustment

A two-component survival mixture model is proposed to analyse a set of ischaemic stroke-specific mortality data. The survival experience of stroke patients after index stroke may be described by a subpopulation of patients in the acute condition and another subpopulation of patients in the chronic phase. To adjust for the inherent correlation of observations due to random hospital effects, a mixture model of two survival functions with random effects is formulated. Assuming a Weibull hazard in both components, an EM algorithm is developed for the estimation of fixed effect parameters and variance components. A simulation study is conducted to assess the performance of the two-component survival mixture model estimators. Simulation results confirm the applicability of the proposed model in a small sample setting. Copyright (C) 2004 John Wiley Sons, Ltd.

A non-invasive method for silencing gene transcription in honeybees maintained under natural conditions

in the Apis mellifera post-genomic era, RNAi protocols have been used in functional approaches. However, sample manipulation and invasive methods such as injection of double-stranded RNA (dsRNA) can compromise physiology and survival. To circumvent these problems, we developed a non-invasive method for honeybee gene knockdown, using a well-established vitellogenin RNAi system as a model. Second instar larvae received dsRNA for vitellogenin (dsVg-RNA) in their natural diet. For exogenous control, larvae received dsRNA for GFP (dsGFP-RNA). Untreated larvae formed another control group. Around 60% of the treated larvae naturally developed until adult emergence when 0.5 mu g of dsVg-RNA or dsGFP-RNA was offered while no larvae that received 3.0 mu g of dsRNA reached pupal stages. Diet dilution did not affect the removal rates. Viability depends not only on the delivered doses but also on the internal conditions of colonies. The weight of treated and untreated groups showed no statistical differences. This showed that RNAi ingestion did not elicit drastic collateral effects. Approximately 90% of vitellogenin transcripts from 7-day-old workers were silenced compared to controls. A large number of samples are handled in a relatively short time and smaller quantities of RNAi molecules are used compared to invasive methods. These advantages culminate in a versatile and a cost-effective approach. (c) 2008 Elsevier Ltd. All rights reserved.

Activity of platinum-tin catalysts prepared by the Pechini-Adams method for the electrooxidation of ethanol

Pt-Sn electrocatalysts of different compositions were prepared and dispersed on carbon Vulcan XC-72 using the Pechini-Adams method. The catalysts were characterized by energy dispersive X-ray analysis and X-ray diffraction. The electrochemical properties of these electrode materials were also examined by cyclic voltammetry and chronoamperometric experiments in acid medium. The results showed that the presence of Sn greatly enhances the activity of Pt towards the electrooxidation of ethanol. Moreover, it contributes to reduce the amount of noble metal in the anode of direct alcohol fuel cells, which remains one of the challenges to make the technology of direct alcohol fuel cells possible. Electrolysis of ethanol solutions at 0.55 V vs. RHE allowed to determine by liquid chromatography acetaldehyde and acetic acid as the main reaction products. CO(2) was also analyzed after trapping it in a NaOH solution indicating that the cleavage of the C-C bond in the ethanol molecule did occur during the adsorption process. In situ IR reflectance spectroscopy helped to investigate in more details the reaction mechanism through the identification of the reaction products as well as the presence of some intermediate adsorbed species, such as linearly bonded carbon monoxide. (C) 2009 Elsevier B.V. All rights reserved.

Disposition of MDMA and Metabolites in Human Sweat Following Controlled MDMA Administration

BACKGROUND: Understanding the excretion of 3,4-methylenedioxymethamphetamine (MDMA) and metabolites in sweat is vital for interpretation of sweat tests in drug treatment, criminal justice, and workplace programs. METHODS: Placebo, low (1.0 mg/kg), and high (1.6 mg/kg) doses of oral MDMA were given double-blind in random order to healthy volunteers (n = 15) with histories of MDMA use. Participants resided on the closed clinical research unit for up to 7 days after each dose. Volunteers wore PharmChek (R) sweat patches (n = 640) before, during, and after controlled dosing. Patches were analyzed by solid phase extraction and GC-MS for MDMA, methylenedioxyamphetamine (MDA), 4-hydroxy-3-methoxyamphetamine (HMA), and 4hydroxy-3-methoxymethamphetamine (HMMA). Limits of quantification (LOQ) were 2.5 ng/patch for MDMA and 5 ng/patch for HMA, HMMA, and MDA. RESULTS: MDMA was the primary analyte detected in 382 patches (59.7%), with concentrations up to 3007 ng/patch. MDA was detected in 188 patches (29.4%) at <172 ng/patch, whereas no HMMA or HMA was detected; 224 patches (35.0%) and 60 patches (9.4%) were positive for MDMA and MDA, respectively, at the 25-ng/patch threshold proposed by the Substance Abuse and Mental Health Services Administration. CONCLUSIONS: Sweat testing was shown to be an effective and reliable method for monitoring MDMA use in this controlled MDMA administration study. However, variability in sweat excretion suggests that results should be interpreted qualitatively rather than quantitatively. These data provide a scientific database for interpretation of MDMA sweat test results. (C) 2008 American Association for Clinical Chemistry

Operational regimes for a simplified one-step artificial chaperone refolding method

The artificial chaperone method for protein refolding developed by Rozema et al. (Rozema, D.; Gellman, S. H. J. Am. Chem. Soc. 1995, 117 (8), 2373-2374) involves the sequential dilution of denatured protein into a buffer containing detergent (cetyltrimethylammonium bromide, CTAB) and then into a refolding buffer containing cyclodextrin WD). In this paper a simplified one-step artificial chaperone method is reported, whereby CTAB is added directly to the denatured solution, which is then diluted directly into a refolding buffer containing P-cyclodextrin (P-CD). This new method can be applied at high protein concentrations, resulting in smaller processing volumes and a more concentrated protein solution following refolding. The increase in achievable protein concentration results from the enhanced solubility of CTAB at elevated temperatures in concentrated denaturant. The refolding yields obtained for the new method were significantly higher than for control experiments lacking additives and were comparable to the yields obtained with the classical two-step approach. A study of the effect of beta-CD and CTAB concentrations on refolding yield suggested two operational regimes: slow stripping ( beta-CDXTABsimilar to1), most suited for higher protein concentrations, and fast stripping (beta-CD/CTABsimilar to2.7), best suited for lower protein concentrations. An increased chaotrope concentration resulted in higher refolding yields and an enlarged operational regime.