A model colloidal fluid with competing interactions: bulk and interfacial properties

Using a simple mean-field density functional theory theory (DFT), we investigate the structure and phase behaviour of a model colloidal fluid composed of particles interacting via a pair potential which has a hard core of diameter $\sigma$, is attractive Yukawa at intermediate separations and repulsive Yukawa at large separations. We analyse the form of the asymptotic decay of the bulk fluid correlation functions, comparing results from our DFT with those from the self consistent Ornstein-Zernike approximation (SCOZA). In both theories we find rich crossover behaviour, whereby the ultimate decay of correlation functions changes from monotonic to long-wavelength damped oscillatory decay on crossing certain lines in the phase diagram, or sometimes from oscillatory to oscillatory with a longer wavelength. For some choices of potential parameters we find, within the DFT, a $\lambda$-line at which the fluid becomes unstable with respect to periodic density fluctuations. SCOZA fails to yield solutions for state points near such a $\lambda$-line. The propensity to clustering of particles, which is reflected by the presence of a long wavelength $\gg \sigma$, slowly decaying oscillatory pair correlation function, and a structure factor that exhibits a very sharp maximum at small but non zero wavenumbers, is enhanced in states near the $\lambda$-line. We present density profiles for the planar liquid-gas interface and for fluids adsorbed at a planar hard wall. The presence of a nearby $\lambda$-transition gives rise to pronounced long-wavelength oscillations in the one-body densities at both types of interface.Comment: 14 pages, 11 figure

In vitro toxin production by fusarium solani f. sp. piperis.

Fusarium solani f. sp. piperis (teleomórfico: Nectria haematococca f. sp. piperis) agente causal da podridão-das-raízes e do secamento-dos-ramos da pimenteira-do-reino (Piper nigrum) produz metabólitos secundários com propriedades tóxicas capazes de induzir descoloração das nervuras em folhas destacadas e murcha em micro-estacas. A produção de metabólitos tóxicos alcançou o pico após 25 dias de incubação, sob iluminação. Variações no pH do filtrado da cultura não aumentaram o efeito tóxico, entretanto, quando o pH foi ajustado antes da esterilização do meio de cultura, uma resposta biológica mais intensa foi observada, atingindo o máximo em pH 6,0. Isolados que produziram pigmentos vermelhos no meio de cultura foram mais eficientes em produzir filtrados biologicamente ativos do que aqueles que produziram filtrados de coloração rósea ou branca sugerindo que estes pigmentos podem estar relacionados com atividade toxigênica. Folhas destacadas de sete cultivares de pimenta-do-reino e Piper betle exibiram sintomas de descoloração das nervuras após imersão em filtrados autoclavado e não autoclavado indicando a natureza termoestável destes metabólitos tóxicos

Phase separation in fluids exposed to spatially periodic external fields

We consider the liquid-vapor type phase transition for fluids confined within spatially periodic external fields. For a fluid in d=3 dimensions, the periodic field induces an additional phase, characterized by large density modulations along the field direction. At the triple point, all three phases (modulated, vapor, and liquid) coexist. At temperatures slightly above the triple point and for low (high) values of the chemical potential, two-phase coexistence between the modulated phase and the vapor (liquid) is observed. We study this phenomenon using computer simulations and mean-field theory for the Ising model. The theory shows that, in order for the modulated phase to arise, the field wavelength must exceed a threshold value. We also find an extremely low tension of the interface between the modulated phase and the vapor/liquid phases. The tension is of the order 10^{-4} kB T per squared lattice spacing, where kB is the Boltzmann constant, and T the temperature. In order to detect such low tensions, a new simulation method is proposed. We also consider the case of d=2 dimensions. The modulated phase then does not survive, leading to a radically different phase diagram.Comment: 11 pages, 14 figure

X-Ray Diffraction and Reflectance Spectroscopy of Murchison Powders (CM2) After Thermal Analysis Under Reducing Conditions to Final Temperatures Between 300 and 1300c

The asteroids Ryugu and Bennu have spectral characteristics in common with CI/CM type carbonaceous chondrites and are target bodies for JAXAs Hayabusa2 and NASAs OSIRIS-Rex missions, respectively. Analog studies, based primarily on the Murchison CM2 chondrite, provide a pathway to separate spectral properties resulting space weathering from those inherent to parent-body, mineralogy, chemistry, and processes. Ryugu shares spectral properties with thermally metamorphosed and partly dehydrated CI/CM chondrites. We have undertaken a multidisciplinary study of the thermal decomposition of Murchison powder samples as an analog to metamorphic process that may have occurred on Ryugu. Bulk analyses include thermal And evolved gas analysis, X-ray diffraction (XRD), and VIS-NIR and Mssbauer spectroscopy; micro- to nanoscale analyses included scanning and transmission electron microscopy and electron probe micro analysisWe report here XRD and VIS-NIR analyses of pre- and post-heated Murchison powders, and in a companion paper report results from multiple electron beam techniques

Higher education, mature students and employment goals: policies and practices in the UK

This article considers recent policies of Higher Education in the UK, which are aimed at widening participation and meeting the needs of employers. The focus is on the growing population of part-time students, and the implications of policies for this group. The article takes a critical perspective on government policies, using data from a major study of mature part-time students, conducted in two specialist institutions in the UK, a London University college and a distance learning university. Findings from this study throw doubt on the feasibility of determining a priori what kind of study pathway is most conducive for the individual in terms of employment gains and opportunities for upward social mobility. In conclusion, doubts are raised as to whether policies such as those of the present UK government are likely to achieve its aims. Such policies are not unique to the UK, and lessons from this country are relevant to most of the developed world

Light emitting diode (LED) color and broiler growth: effect of supplementing blue/green LED to white LED light on broiler growth, stress, and welfare

Light emitting diode (LED) lighting provides an affordable lighting option for use in commercial poultry production. However, more information is needed to understand the effects of LED color on broiler welfare and growth. Five consecutive flocks (1 in summer, 1 in fall, 2 in winter, and 1 in spring) of straight run Ross 708 × Ross 708 broilers were reared in commercial type barns for 45 D. For white only (WO) treatment, birds were reared under white LED only (Agrishift MLB). For white supplemented (WS) treatment, birds were reared under white LED (Agrishift MLB) in the center aisle, with supplemental blue/green LED lighting (Agrishift MLBg) above the feed and water lines on either side of the barn. Each barn housed 26,200 chicks, and there were 2 barns in each treatment (n = 52,400/treatment). Treatments were rotated among barns between each flock. On day 45, blood samples were collected from 20 birds/barn (n = 40/treatment) to assess the plasma corticosterone (CORT) level and heterophil/lymphocyte ratio. On day 45, 100 birds/barn (n = 200/treatment) were weighed individually and assigned scores for hock burn and foot pad dermatitis. All measures were affected by trial (P \u3c 0.001). Plasma CORT and body weight were affected by the treatment × trial interaction (P ≤ 0.001). Overall, birds in the WS treatment had higher day 45 live body weight (P \u3c 0.001) and lower hock burn scores (P = 0.032) than birds in the WO treatment. Birds in the WS treatment had higher day 45 body weight overall (P \u3c 0.001) and in trials 1, 3, and 5, although the overall body weight was lower in trials 1, 3, and 5 than in trials 2 and 4. Supplemental blue/green LED improved hock burn scores and increased overall day 45 body weight. However, trial differences suggest that more data are needed to determine whether supplementing blue/green LED to white LED improves body weight gain in mixed sex broiler chickens

Comparison of an intermittent, short-dawn/dusk photoperiod with an increasing, long-dawn/dusk photoperiod on broiler growth, stress, and welfare

Photoperiod has been shown to significantly affect broiler performance. However, the effects of the traditional 1-min dimming period on broiler growth and welfare are unclear. In this study, 4 consecutive trials were conducted to compare the effects of an intermittent, short-dawn/dusk photoperiod (ISD) to an increasing, long-dawn/dusk photoperiod (ILD) on broiler growth, stress, and welfare. Straight run day-of-hatch Ross 708 × Ross 708 broilers were placed in 1 of 4 commercial broiler barns (2 b of 26,200 birds each per treatment) and grown to 45 D of age. The photoperiod in the ISD treatment consisted of 24L:0D day 0 to 6, 16L:8D day 7 to 13, 12L:4D:2L:6D day 14 to 20, 12L:4D:3L:5D day 21 to 27, 12L:4D:4L:4D day 28 to 41, and 13L:3D:5L:3D day 42 to 45, with a 1-min transition between light and dark periods. The photoperiod in the ILD treatment consisted of 23L:1D day 0 to 7, 16L:8D day 8 to 21, 18L:6D day 22 to 32, and 20L:4D day 33 to 45, with a 1-min light/dark transition period day 0 to 7 and a 30-min transition period day 8 to 45. Treatments were rotated among the barns between trials. On day 45, blood samples were collected from 20 birds/barn (n = 40/treatment) to assess plasma corticosterone (CORT) and heterophil/lymphocyte (H/L) ratio. One hundred birds per barn (n = 200/treatment) were weighed individually and assigned scores for hock burn, foot pad dermatitis, and feather condition on day 45. Trial differences were observed for all measures (P ≤ 0.001). Birds in the ISD treatment were heavier on day 45 (P \u3c 0.001) and had lower hock burn (P = 0.044) and foot pad dermatitis (P \u3c 0.001) scores. Birds in the ILD treatment had lower plasma CORT (P \u3c 0.001) and H/L ratio (P \u3c 0.001). No treatment differences were observed for feather condition (P \u3e 0.05). Overall, birds reared under the intermittent, short-dawn/dusk photoperiod had higher day 45 live body weights and lower hock burn and foot pad dermatitis scores, whereas those reared under the increasing, long-dawn/dusk photoperiod had reduced measures of short-term and long-term stress

A systematic review of Patient Safety in Mental Health: a protocol based on the Inpatient Setting

Background Despite the growing international interest in patient safety as a discipline, there has been a lack of exploration of its application to mental health. It cannot be assumed that findings based upon physical health in acute care hospitals can be applied to mental health patients, disorders and settings. To the authors’ knowledge, there has only been one review of the literature that focuses on patient safety research in mental health settings, conducted in Canada in 2008. We have identified a need to update this review and develop the methodology in order to strengthen the findings and disseminate internationally for advancement in the field. This systematic review will explore the existing research base on patient safety in mental health within the inpatient setting. Methods To conduct this systematic review, a thorough search across multiple databases will be undertaken, based upon four search facets (“mental health”, “patient safety”, “research” and “inpatient setting”). The search strategy has been developed based upon the Canadian review accompanied with input from the National Reporting and Learning System (NRLS) taxonomy of patient safety incidents and the Diagnostic and Statistical Manual of Mental Disorders (5th edition). The screening process will involve perspectives from at least two researchers at all stages with a third researcher invited to review when discrepancies require resolution. Initial inclusion and exclusion criteria have been developed and will be refined iteratively throughout the process. Quality assessment and data extraction of included articles will be conducted by at least two researchers. A data extraction form will be developed, piloted and iterated as necessary in accordance with the research question. Extracted information will be analysed thematically. Discussion We believe that this systematic review will make a significant contribution to the advancement of patient safety in mental health inpatient settings. The findings will enable the development and implementation of interventions to improve the quality of care experienced by patients and support the identification of future research priorities. Registration This systematic review was registered to the PROSPERO database on the 15th February 2016 (registration number CRD42016034057) and updated on 26th April 2016

Phase separation dynamics in a two-dimensional magnetic mixture

Based on classical density functional theory (DFT), we investigate the demixing phase transition of a two-dimensional, binary Heisenberg fluid mixture. The particles in the mixture are modeled as Gaussian soft spheres, where one component is characterized by an additional classical spin-spin interaction of Heisenberg type. Within the DFT we treat the particle interactions using a mean-field approximation. For certain magnetic coupling strengths we calculate phase diagrams in the density-concentration plane. For sufficiently large coupling strengths and densities, we find a demixing phase transition driven by the ferromagnetic interactions of the magnetic species. We also provide a microscopic description (i.e., density profiles) of the resulting non-magnetic/magnetic fluid-fluid interface. Finally, we investigate the phase separation using dynamical density functional theory (DDFT), considering both nucleation processes and spinodal demixing.Comment: 15 pages, 10 figure