3,895 research outputs found
A Finite-Size Scaling Study of a Model of Globular Proteins
Grand canonical Monte Carlo simulations are used to explore the metastable
fluid-fluid coexistence curve of the modified Lennard-Jones model of globular
proteins of ten Wolde and Frenkel (Science, v277, 1975 (1997)). Using both
mixed-field finite-size scaling and histogram reweighting methods, the joint
distribution of density and energy fluctuations is analyzed at coexistence to
accurately determine the critical-point parameters. The subcritical coexistence
region is explored using the recently developed hyper-parallel tempering Monte
Carlo simulation method along with histogram reweighting to obtain the density
distributions. The phase diagram for the metastable fluid-fluid coexistence
curve is calculated in close proximity to the critical point, a region
previously unattained by simulation.Comment: 17 pages, 10 figures, 2 Table
Genetic Variants and Phenotypic Characteristics ofSalmonellaTyphimurium-Resistant Mutants after Exposure to Carvacrol
The emergence of antimicrobial resistance has raised questions about the safety of essential oils and their individual constituents as food preservatives and as disinfection agents. Further research is required to understand how and under what conditions stable genotypic resistance might occur in food pathogens. Evolution experiments onSalmonellaTyphimurium cyclically exposed to sublethal and lethal doses of carvacrol permitted the isolation of SeSCar and SeLCar strains, respectively. Both evolved strains showed a significant increase in carvacrol resistance, assessed by minimum inhibitory and bactericidal concentrations, the study of growth kinetics in the presence of carvacrol, and the evaluation of survival under lethal conditions. Moreover, antibiotic susceptibility tests revealed a development of SeLCar resistance to a wide range of antibiotics. Whole genome sequencing allowed the identification of single nucleotide variations in transcriptional regulators of oxidative stress-response:yfhPin SeSCar andsoxRin SeLCar, which could be responsible for the increased resistance by improving the response to carvacrol and preventing its accumulation inside the cell. This study demonstrates the emergence of S. Typhimurium-resistant mutants against carvacrol, which might pose a risk to food safety and should therefore be considered in the design of food preservation strategies, or of cleaning and disinfection treatments
Water loss in horticultural products. Modelling, data analysis and theoretical considerations
The water loss of individual fruit (melon, plum and mandarin) was analysed using the traditional diffusion based approach and a kinetic approach. Applying simple non linear regression, both approaches are the same, resulting in a quite acceptable analysis. However, by applying mixed effects non linear regression analysis, explicitly including the variation over the individuals, the kinetic approach was found to reflect the processes occurring during mass loss better than the diffusion approach. All the variation between the individuals in a batch could be attributed to the initial mass or size of the individuals. The fraction of the fruit mass that is available for transpiration is the key item in the water loss process, rather than the skin resistance and fruit area. Obtained explained parts are well over 99%
Automated Grain Yield Behavior Classification
A method for classifying grain stress evolution behaviors using unsupervised learning techniques is presented. The method is applied to analyze grain stress histories measured in-situ using high-energy X-ray diffraction microscopy (HEDM) from the aluminum-lithium alloy Al-Li 2099 at the elastic-plastic transition (yield). The unsupervised learning process automatically classified the grain stress histories into four groups: major softening, no work-hardening or softening, moderate work-hardening, and major work-hardening. The orientation and spatial dependence of these four groups are discussed. In addition, the generality of the classification process to other samples is explored
Evidence for self-sustained MoSi2 formation during room-temperature high-energy ball milling of elemental powders
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/83393/1/Ma_JMR.pd
Integrating Social Justice Practices into Graduate Training: Collaborating with Stakeholders to Adapt Professional Development in Puerto Rico
Treating trauma has become an international social justice concern, with increasing numbers of graduate training programs prioritizing how to conceptualize needs and interventions within a trauma-informed framework. Minimal research and guidelines exist for adapting these trauma-informed practices for the local community context. Additionally, trauma-informed practices often fail to consider ongoing structural issues faced by oppressed communities such as poverty and racism. Social work, psychology, and counseling graduate training programs often rely on a cultural competency framework instead of a social justice framework that addresses racism and Whiteness. During our graduate Counseling and School Psychology training program at the University of Massachusetts Boston, we collaborated with stakeholders at a school and community center in San Juan, Puerto Rico to culturally adapt and deliver trainings in trauma-informed practices for staff using an ecological validity framework. Using our work in Puerto Rico as a case study, this paper addresses the cultural adaptation of trauma-informed practices and factors to consider when implementing trauma-informed practices, emphasizing the need for creating safety. Strategies for embedding this trauma-informed work into mental health graduate training programs and recommendations for working with individuals from marginalized groups in school settings are discussed
On pricing of interest rate derivatives
At present, there is an explosion of practical interest in the pricing of
interest rate (IR) derivatives. Textbook pricing methods do not take into
account the leptokurticity of the underlying IR process. In this paper, such a
leptokurtic behaviour is illustrated using LIBOR data, and a possible
martingale pricing scheme is discussed.Comment: 9 pages, 13 figure
Objective evaluation of two deworming regimens in young Thoroughbreds using average daily gain, body condition score, and parasitological parameters
Experimental study of turbulence past thin tabs
The turbulence past thin tabs of rectangular, triangular, and ellipsoidal geometries is experimentally investigated using particle image velocimetry at Reynolds number Re=2000 and Re=12900 based on the tabs height and freestream velocity. Turbulence statistics including streamwise velocity, turbulent kinetic energy (TKE), and vortex swirling strength are obtained in the symmetry plane of each tab. The results show a strong dependency of the tab geometry on the strength of the induced vortical structures at the low Re. The turbulent flow regime at high Re promotes high shear stress and TKE production right past the tabs, where the rectangular tab induces greater mixing. The spanwise vortices from the rectangular tab have an average vortex cores radius 20% larger and nearly 30% greater circulation as compared to those from the ellipsoidal tab. Compared to the ones produced by the triangular tab, the core radius is 25% larger and the circulation is almost 50% higher. Our results also show, for the rst time, that hairpin structures are possible in triangular tabs. Finally, we conclude that geometrical singularity plays an important role in the strength of the primary vortical structures shed by the tabs
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