Secondary Electron Yield Measurements of Fermilab's Main Injector Vacuum Vessel

We discuss the progress made on a new installation in Fermilab's Main Injector that will help investigate the electron cloud phenomenon by making direct measurements of the secondary electron yield (SEY) of samples irradiated in the accelerator. In the Project X upgrade the Main Injector will have its beam intensity increased by a factor of three compared to current operations. This may result in the beam being subject to instabilities from the electron cloud. Measured SEY values can be used to further constrain simulations and aid our extrapolation to Project X intensities. The SEY test-stand, developed in conjunction with Cornell and SLAC, is capable of measuring the SEY from samples using an incident electron beam when the samples are biased at different voltages. We present the design and manufacture of the test-stand and the results of initial laboratory tests on samples prior to installation.Comment: 3 pp. 3rd International Particle Accelerator Conference (IPAC 2012) 20-25 May 2012, New Orleans, Louisian

Current and projected global distribution of Phytophthora cinnamomi, one of the world's worst plant pathogens

Globally, Phytophthora cinnamomi is listed as one of the 100 worst invasive alien species and active management is required to reduce impact and prevent spread in both horticulture and natural ecosystems. Conversely, there are regions thought to be suitable for the pathogen where no disease is observed. We developed a climex model for the global distribution of P. cinnamomi based on the pathogen's response to temperature and moisture and by incorporating extensive empirical evidence on the presence and absence of the pathogen. The climex model captured areas of climatic suitability where P. cinnamomi occurs that is congruent with all available records. The model was validated by the collection of soil samples from asymptomatic vegetation in areas projected to be suitable by the model for which there were few records. DNA was extracted, and the presence or absence of P. cinnamomi was determined by high-throughput sequencing (HTS). While not detected using traditional isolation methods, HTS detected P. cinnamomi at higher elevations in eastern Australia and central Tasmania as projected by the climex model. Further support for the climex model was obtained using the large data set from south-west Australia where the proportion of positive records in an area is related to the Ecoclimatic Index value for the same area. We provide for the first time a comprehensive global map of the current P. cinnamomi distribution, an improved climex model of the distribution, and a projection to 2080 of the distribution with predicted climate change. This information provides the basis for more detailed regional-scale modelling and supports risk assessment for governments to plan management of this important soil-borne plant pathogen

Effect of Antigonon leptopus extract in corn starch-glycerol based film as colourimetric indicator film for monitoring fish freshness

A colourimetric indicator can be used to test the freshness of fish in a rapid, straightforward and non-destructive manner. Anthocyanin, a natural dye found in Antigonon leptopus flowers, has a sensitive colour reactivity to a wide range of pH levels and can be made into colourimetric indicator films on a laboratory scale, making it a viable replacement for artificial dyes. The study's purpose was to see how the concentration of A. leptopus extract affected the colourimetric assessment of fish freshness. Ethanol was used to extract anthocyanin from A. leptopus. FTIR and pHrespond spectroscopies were used to characterise the extracts. Colourimetric indicator films were developed to assess fish freshness by incorporating A. leptopus extract into a corn starch-glycerol matrix via the solution casting method, with concentrations of 10%, 30% and 50%, respectively. The effect of A. leptopus extract on visual aspects, thickness, morphology, FTIR spectra, UV-Vis spectra and colour responses was analysed. Microbial analysis, TVB-N contents, firmness, and pH of the fish samples were analysed after storage. The colour of the original films became darker as the extracted content increased. There was no significant (p>0.05) effect of A. leptopus extract on film thickness. SEM micrographs revealed that the composite films had homogeneous and whitish granules on the surface and that increasing the A. leptopus extract concentration caused the films to become rougher. FTIR and UV-Vis spectroscopies showed successful binding between A. leptopus extracts and corn starch-glycerol film. With increasing pH, the colour change of the films exposed to pH = 3-11 solutions was no significant difference due to improper storage. An increase in the microbial population, TVB-N content and pH was observed over the storage period as a result of fish deterioration. Colour changes were also identified in the film which became darker. Overall, colourimetric indicator film with 50% A. leptopus extract was found to be the optimal formulation since it had the highest values in ∆E* during progressive spoilage of fish

Finite Element Convergence for the Joule Heating Problem with Mixed Boundary Conditions

We prove strong convergence of conforming finite element approximations to the stationary Joule heating problem with mixed boundary conditions on Lipschitz domains in three spatial dimensions. We show optimal global regularity estimates on creased domains and prove a priori and a posteriori bounds for shape regular meshes.Comment: Keywords: Joule heating problem, thermistors, a posteriori error analysis, a priori error analysis, finite element metho

The Five Factor Model of personality and evaluation of drug consumption risk

The problem of evaluating an individual's risk of drug consumption and misuse is highly important. An online survey methodology was employed to collect data including Big Five personality traits (NEO-FFI-R), impulsivity (BIS-11), sensation seeking (ImpSS), and demographic information. The data set contained information on the consumption of 18 central nervous system psychoactive drugs. Correlation analysis demonstrated the existence of groups of drugs with strongly correlated consumption patterns. Three correlation pleiades were identified, named by the central drug in the pleiade: ecstasy, heroin, and benzodiazepines pleiades. An exhaustive search was performed to select the most effective subset of input features and data mining methods to classify users and non-users for each drug and pleiad. A number of classification methods were employed (decision tree, random forest, $k$-nearest neighbors, linear discriminant analysis, Gaussian mixture, probability density function estimation, logistic regression and na{\"i}ve Bayes) and the most effective classifier was selected for each drug. The quality of classification was surprisingly high with sensitivity and specificity (evaluated by leave-one-out cross-validation) being greater than 70\% for almost all classification tasks. The best results with sensitivity and specificity being greater than 75\% were achieved for cannabis, crack, ecstasy, legal highs, LSD, and volatile substance abuse (VSA).Comment: Significantly extended report with 67 pages, 27 tables, 21 figure

Branch-and-lift algorithm for deterministic global optimization in nonlinear optimal control

This paper presents a branch-and-lift algorithm for solving optimal control problems with smooth nonlinear dynamics and potentially nonconvex objective and constraint functionals to guaranteed global optimality. This algorithm features a direct sequential method and builds upon a generic, spatial branch-and-bound algorithm. A new operation, called lifting, is introduced, which refines the control parameterization via a Gram-Schmidt orthogonalization process, while simultaneously eliminating control subregions that are either infeasible or that provably cannot contain any global optima. Conditions are given under which the image of the control parameterization error in the state space contracts exponentially as the parameterization order is increased, thereby making the lifting operation efficient. A computational technique based on ellipsoidal calculus is also developed that satisfies these conditions. The practical applicability of branch-and-lift is illustrated in a numerical example. © 2013 Springer Science+Business Media New York

Current status of Phytophthora in Australia

Among the most economically relevant and environmentally devastating diseases globally are those caused by Phytophthora species. In Australia, production losses in agriculture and forestry results from several well-known cosmopolitan Phytophthora species and infestation of natural ecosystems by Phytophthora cinnamomi have caused irretrievable loss to biodiversity, especially in proteaceous dominated heathlands. For this review, all available records of Phytophthora in Australia were collated and curated, resulting in a database of 7 869 records, of which 2 957 have associated molecular data. Australian databases hold records for 99 species, of which 20 are undescribed. Eight species have no records linked to molecular data, and their presence in Australia is considered doubtful. The 99 species reside in 10 of the 12 clades recognised within the complete phylogeny of Phytophthora. The review includes discussion on each of these species’ status and additional information provided for another 29 species of concern. The first species reported in Australia in 1900 was Phytophthora infestans. By 2000, 27 species were known, predominantly from agriculture. The significant increase in species reported in the subsequent 20 years has coincided with extensive surveys in natural ecosystems coupled with molecular taxonomy and the recognition of numerous new phylogenetically distinct but morphologically similar species. Routine and targeted surveys within Australian natural ecosystems have resulted in the description of 27 species since 2009. Due to the new species descriptions over the last 20 years, many older records have been reclassified based on molecular identification. The distribution of records is skewed toward regions with considerable activity in high productivity agriculture, horticulture and forestry, and native vegetation at risk from P. cinnamomi. Native and exotic hosts of different Phytophthora species are found throughout the phylogeny; however, species from clades 1, 7 and 8 are more likely to be associated with exotic hosts. One of the most difficult challenges to overcome when establishing a pest status is a lack of reliable data on the current state of a species in any given country or location. The database compiled here for Australia and the information provided for each species overcomes this challenge. This review will aid federal and state governments in risk assessments and trade negotiations by providing a comprehensive resource on the current status of Phytophthora species in Australia

Reionization by active sources and its effects on the cosmic microwave background

We investigate the possible effects of reionization by active sources on the cosmic microwave background. We concentrate on the sources themselves as the origin of reionization, rather than early object formation, introducing an extra period of heating motivated by the active character of the perturbations. Using reasonable parameters, this leads to four possibilities depending on the time and duration of the energy input: delayed last scattering, double last scattering, shifted last scattering and total reionization. We show that these possibilities are only very weakly constrained by the limits on spectral distortions from the COBE FIRAS measurements. We illustrate the effects of these reionization possibilities on the angular power spectrum of temperature anisotropies and polarization for simple passive isocurvature models and simple coherent sources, observing the difference between passive and active models. Finally, we comment on the implications of this work for more realistic active sources, such as causal white noise and topological defect models. We show for these models that non-standard ionization histories can shift the peak in the CMB power to larger angular scales.Comment: 21 pages LaTeX with 11 eps figures; replaced with final version accepted for publication in Phys. Rev.

Partial-wave analysis of the eta pi+ pi- system produced in the reaction pi-p --> eta pi+ pi- n at 18 GeV/c

A partial-wave analysis of 9082 eta pi+ pi- n events produced in the reaction pi- p --> eta pi+ pi- n at 18.3 GeV/c has been carried out using data from experiment 852 at Brookhaven National Laboratory. The data are dominated by J^{PC} = 0^{-+} partial waves consistent with observation of the eta(1295) and the eta(1440). The mass and width of the eta(1295) were determined to be 1282 +- 5 MeV and 66 +- 13 Mev respectively while the eta(1440) was observed with a mass of 1404 +- 6 MeV and width of 80 +- 21 MeV. Other partial waves of importance include the 1++ and the 1+- waves. Results of the partial wave analysis are combined with results of other experiments to estimate f1(1285) branching fractions. These values are considerably different from current values determined without the aid of amplitude analyses.Comment: 22 pages, 8 figure

A partial wave analysis of the π0π0\pi ^0\pi ^0 system produced in π−p\pi ^-p charge exchange collisions

A partial wave analysis of the of the $\pi ^0\pi ^0$ system produced in the charge exchange reaction: $\pi ^-p\to \pi ^0\pi ^0n$ at an incident momentum of $18.3 GeV/c$ is presented as a function of ${\pi ^0\pi ^0}$ invariant mass, $m_{\pi^0\pi^0}$, and momentum transfer squared, $| {t} |$, from the incident $\pi^-$ to the outgoing ${\pi ^0\pi ^0}$ system.Comment: 24 pages total,8 pages text, 14 figures, 1 table. Submitted to Phys Rev