Ice supersaturation and the potential for contrail formation in a changing climate

Ice supersaturation (ISS) in the upper troposphere and lower stratosphere is important for the formation of cirrus clouds and long-lived contrails. Cold ISS (CISS) regions (taken here to be ice-supersaturated regions with temperature below 233 K) are most relevant for contrail formation.We analyse projected changes to the 250 hPa distribution and frequency of CISS regions over the 21st century using data from the Representative Concentration Pathway 8.5 simulations for a selection of Coupled Model Intercomparison Project Phase 5 models. The models show a global-mean, annual-mean decrease in CISS frequency by about one-third, from 11 to 7% by the end of the 21st century, relative to the present-day period 1979–2005. Changes are analysed in further detail for three subregions where air traffic is already high and increasing (Northern Hemisphere mid-latitudes) or expected to increase (tropics and Northern Hemisphere polar regions). The largest change is seen in the tropics, where a reduction of around 9 percentage points in CISS frequency by the end of the century is driven by the strong warming of the upper troposphere. In the Northern Hemisphere mid-latitudes the multi-model-mean change is an increase in CISS frequency of 1 percentage point; however the sign of the change is dependent not only on the model but also on latitude and season. In the Northern Hemisphere polar regions there is an increase in CISS frequency of 5 percentage points in the annual mean. These results suggest that, over the 21st century, climate change may have large impacts on the potential for contrail formation; actual changes to contrail cover will also depend on changes to the volume of air traffic, aircraft technology and flight routing.

Decimal growth stages for precision wheat production in changing environments?

The utility of the decimal growth stage (DGS) scoring system for cereals is reviewed. The DGS is the most widely used scale in academic and commercial applications because of its comprehensive coverage of cereal developmental stages, the ease of use and definition provided and adoption by official agencies. The DGS has demonstrable and established value in helping to optimise the timing of agronomic inputs, particularly with regard to plant growth regulators, herbicides, fungicides and soluble nitrogen fertilisers. In addition, the DGS is used to help parameterise crop models, and also in understanding the response and adaptation of crops to the environment. The value of the DGS for increasing precision relies on it indicating, to some degree, the various stages in the development of the stem apex and spike. Coincidence of specific growth stage scores with the transition of the apical meristem from a vegetative to a reproductive state, and also with the period of meiosis, is unreliable. Nonetheless, in pot experiments it is shown that the broad period of booting (DGS 41–49) appears adequate for covering the duration when the vulnerability of meiosis to drought and heat stress is exposed. Similarly, the duration of anthesis (61–69) is particularly susceptible to abiotic stresses: initially from a fertility perspective, but increasingly from a mean grain weight perspective as flowering progresses to DGS 69 and then milk development. These associations with DGS can have value at the crop level of organisation: for interpreting environmental effects, and in crop modelling. However, genetic, biochemical and physiological analysis to develop greater understanding of stress acclimation during the vegetative state, and tolerance at meiosis, does require more precision than DGS can provide. Similarly, individual floret analysis is needed to further understand the genetic basis of stress tolerance during anthesis.

Mixture of changing uniaxial micellar forms in lyotropic biaxial nematics

Lyotropic nematics consisting of surfactant-cosurfactant water solutions may present a biaxial phase or direct U(+) <-> U(-) transitions, in different regions of the temperature-relative concentration phase diagram, for different systems and compositions. We propose that these may be related to changes of uniaxial micellar form, which may occur either smoothly or abruptly. Smooth change of cylinder-like into disc-like shapes requires a distribution of Maier-Saupe interaction constants and we consider two limiting cases for the distribution of forms: a single Gaussian and a double Gaussian. Alternatively, an abrupt change of form is described by a discontinuous distribution of interaction constants. Our results show that the dispersive distributions yield a biaxial phase, while an abrupt change of shape leads to coexistence of uniaxial phases. Fitting the theory to the experiment for the ternary system KL/decanol/D2O leads to transition lines in very good agreement with experimental results. In order to rationalise the results of the comparison, we analyse temperature and concentration form dependence, which connects micellar and experimental macroscopic parameters. Physically consistent variations of micellar asymmetry, amphiphile partitioning and volume are obtained. To the best of the authors` knowledge, this is the first truly statistical microscopic approach that is able to model experimentally observed lyotropic biaxial nematic phases.

Enhanced visualization of histological samples with an adjustable RGB contrast system with application for tissue used in photodynamic therapy

The analysis of histological sections has long been a valuable tool in the pathological studies. The interpretation of tissue conditions, however, relies directly on visual evaluation of tissue slides, which may be difficult to interpret because of poor contrast or poor color differentiation. The Chromatic Contrast Visualization System (CCV) combines an optical microscope with electronically controlled light-emitting diodes (LEDs) in order to generate adjustable intensities of RGB channels for sample illumination. While most image enhancement techniques rely on software post-processing of an image acquired under standard illumination conditions, CCV produces real-time variations in the color composition of the light source itself. The possibility of covering the entire RGB chromatic range, combined with the optical properties of the different tissues, allows for a substantial enhancement in image details. Traditional image acquisition methods do not exploit these visual enhancements which results in poorer visual distinction among tissue structures. Photodynamic therapy (PDT) procedures are of increasing interest in the treatment of several forms of cancer. This study uses histological slides of rat liver samples that were induced to necrosis after being exposed to PDT. Results show that visualization of tissue structures could be improved by changing colors and intensities of the microscope light source. PDT-necrosed tissue samples are better differentiated when illuminated with different color wavelengths, leading to an improved differentiation of cells in the necrosis area. Due to the potential benefits it can bring to interpretation and diagnosis, further research in this field could make CCV an attractive technique for medical applications.

Creating meanings, changing contexts: contested sustainability in the Brazilian beef industry

O objetivo desta pesquisa é compreender de que forma as organizações moldam seu ambiente, analisando por que algumas práticas tornam-se reconhecidas como ‘sustentáveis’ na indústria de carne bovina brasileira. O estudo dialoga com a literatura de institucionalismo organizacional ao apontar a necessidade de considerar a política (i.e. as negociações entre atores) e significados, a fim de entender como a estabilidade e a mudança institucional ocorrem em um contexto situado (i.e. em um tempo e espaço específicos). A pesquisa conclui que os entendimentos sobre o que poderia ser reconhecido como ‘sustentabilidade’ são o resultado de atores moldando o seu ambiente por meio de ações e interações que produzem significados. Seguindo uma abordagem de hegemonia, essas disputas não são apenas entre os atores que procuram vantagens recursivas, mas também procuram defender ou atacar as lógicas sociais que apoiam a posição dominante dos atores. Além disso, os atores exercem sua agência sobre as condições no presente (i.e. contexto situado), com base em um passado herdado e com o objetivo de produzir um futuro que eles imaginam. Para analisar tais processos uma abordagem de hegemonia entre atores e lógicas sociais foi desenvolvida para destacar a ordem de negociação, uma arena em que os atores lutam pela hegemonia. Como resultado de tais negociações, uma questão focal emerge, influenciando o discurso e interesses dos atores, bem como justificando as iniciativas, programas e tecnologias sobre tal questão; construindo, portanto, o consenso. Baseando-se em Realismo Crítico e Análise Crítica do Discurso, a pesquisa desenvolveu um estudo de caso longitudinal suportado por documentos públicos e confidenciais e entrevistas com especialistas, para examinar o caminho da sustentabilidade na indústria de carne bovina brasileira. Identificou-se três contextos diferentes para agência em relação à sustentabilidade. Enquanto no primeiro verifica-se um silêncio sobre práticas de sustentabilidade, o segundo enfatiza a emergência do desmatamento da Amazônia como uma questão focal, devido à agência do Greenpeace e MPF que força a indústria a desenvolver um sistema de monitoramento que rastreie seus fornecedores de gado de modo a evitar compra de suprimentos associadas ao desmatamento da Amazônia, dentre outras atividades ilegais. Finalmente, durante o terceiro contexto, o sistema de monitoramento permite que indústria de carne bovina se aproprie da sustentabilidade, assim o setor da carne passa a construir a sua legitimidade para influenciar sobre os riscos e oportunidades associadas ao contexto da sustentabilidade. Em termos de lógicas sociais, o desmatamento na Amazônia foi denunciado como um problema ambiental, nesta indústria, ancorado em algumas características da lógica do capitalismo, como a gestão de riscos, inovação e aumento da produtividade, cadeia de fornecimento global e governança. Embora este ataque questione a racionalidade da maximização racional lucro, impondo restrições ambientais para o comportamento das empresas, a solução desenvolvida é também ancorada sobre as mesmas características do capitalismo empregadas para atacá-lo. Como consequência, uma mudança gradual é ilustrada por uma transformação na ‘eficiência quantitativa’ do capitalismo, o aumento da produtividade devido à mudança da proporção de recursos consumidos para produção e à preocupação em evitar o desmatamento da Amazônia. No entanto, a ‘eficiência qualitativa’ do capitalismo é preservada uma vez que os grupos dominantes no poder ainda estão controlando os meios de produção e os recursos a eles associados (i.e. dinheiro, poder e legitimidade). Uma vez que estes processos de negociações são mediados pela racionalidade de se evitar risco aos negócios, consequentemente, a maximização do lucro, o núcleo duro da lógica do capitalismo é preservado. Portanto, os grupos dominantes mantêm sua hegemonia.

Analysis of cardiovascular system responses to forced vital capacity in COPD

CONTEXTUALIZAÇÃO: O teste de capacidade vital forçada (CVF) é rotineiramente realizado na avaliação da função pulmonar de pacientes com doença pulmonar obstrutiva crônica (DPOC). Entretanto, permanece pouco compreendida a influência do teste de CVF sobre o sistema cardiovascular de pacientes com DPOC. OBJETIVOS: Analisar o comportamento da frequência cardíaca (FC), pressão arterial (PA) e variabilidade da frequência cardíaca (VFC) no teste de CVF na DPOC. MÉTODOS: Dezenove homens com DPOC (72 ± 7 anos, no estágio de gravidade GOLD I=3, II=5, III=7 e IV=4 pacientes) realizaram a manobra de CVF e tiveram sua FC monitorada durante todo o exame, e a VFC analisada nos domínios do tempo (rMSSD) e da frequência (BF, AF e BF/AF) durante o repouso, antes e após a melhor manobra de CVF. A PA foi analisada no repouso, imediatamente ao final da manobra de CVF e 10 minutos após o término de todos os testes. RESULTADOS: Ao início da manobra de CVF, a FC reduziu (p<0,001) e, em seguida, aumentou progressivamente até o final do teste (p<0,001). Após término da manobra, a FC continuou a aumentar até atingir um pico (p<0,001) e depois caiu rapidamente a valores inferiores aos de repouso (p<0,001) e retornou ao seu valor basal. A PA e os índices da VFC não sofreram alterações nos períodos analisados. CONCLUSÃO: O teste de CVF influencia o comportamento da FC, sem alterar o seu controle autonômico, bem como a PA em pacientes com DPOC nos períodos analisados.

On the global dynamics of the Rabinovich system

In this paper by using the Poincare compactification in R(3) make a global analysis of the Rabinovich system(x) over dot = hy - v(1)x + yz, (y) over dot = hx - v(2)y - xz, (z) over dot = -v(3)z + xy,with (x, y, z) is an element of R(3) and ( h, v(1), v(2), v(3)) is an element of R(4). We give the complete description of its dynamics on the sphere at infinity. For ten sets of the parameter values the system has either first integrals or invariants. For these ten sets we provide the global phase portrait of the Rabinovich system in the Poincare ball (i.e. in the compactification of R(3) with the sphere S(2) of the infinity). We prove that for convenient values of the parameters the system has two families of singularly degenerate heteroclinic cycles. Then changing slightly the parameters we numerically found a four wings butterfly shaped strange attractor.

Effect of electron magnetic trapping in a plasma immersion ion implantation system

In this work we describe a two-dimensional computer simulation of magnetic field enhanced plasma immersion implantation system. Negative bias voltage of 10.0 kV is applied to a cylindrical target located on the axis of a grounded vacuum chamber filled with uniform nitrogen plasma. A pair of external coils creates a static magnetic field with main vector component along the axial direction. Thus, a system of crossed ExB field is generated inside the vessel forcing plasma electrons to rotate in azimuthal direction. In addition, the axial variation of the magnetic field intensity produces magnetic mirror effect that enables axial particle confinement. It is found that high-density plasma regions are formed around the target due to intense background gas ionization by the trapped electrons. Effect of the magnetic field on the sheath dynamics and the implantation current density of the PIII system is investigated. By changing the magnetic field axial profile (varying coils separation) an enhancement of about 30% of the retained dose can be achieved. The results of the simulation show that the magnetic mirror configuration brings additional benefits to the PIII process, permitting more precise control of the implanted dose.

Ecological modeling and pest population management: a possible and necessary connection in a changing world

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Interaction between areas of the central nervous system in the control of water intake and arterial pressure in rats

1. Water intake induced by injection of 0.2 M-NaCl into the lateral preoptic area was increased by the injection of angiotensin II into the subfornical organ of rats. The injection of hypertonic saline solution into the subfornical organ increased water intake. However, the increase was lower than when the solution was injected into the lateral preoptic area. The injection of 4 μg angiotensin II into the lateral preoptic area further augmented this effect. 2. Injection of angiotensin II into the subfornical organ caused a rise in blood pressure which preceded the thirst-inducing effect. The injection of 0.2 M NaCl into the subfornical organ caused no changes in blood pressure, whereas the injection of angiotensin II into the lateral preoptic area caused some increase. 3. Dehydration of the lateral preoptic area by means of 0.2 M NaCl in combination with intravenous infusion of angiotensin II caused a summation of effects in terms of the water intake, without changing cardiovascular alterations induced by the infusion of angiotensin II. A summation of effects in the water intake, but not in blood pressure, was also observed when 0.5 M NaCl was infused intravenously in combination with the injection of angiotensin II into the subfornical organ and into the lateral preoptic area. 4. The results indicate that there are interactions between the subfornical organ and lateral preoptic area in the regulation of cardiovascular and thirst mechanisms.

On numerical simulations of a nonlinear self-excited system with two non-ideal sources

In this work, the dynamic behavior of self-synchronization and synchronization through mechanical interactions between the nonlinear self-excited oscillating system and two non-ideal sources are examined by numerical simulations. The physical model of the system vibrating consists of a non-linear spring of Duffing type and a nonlinear damping described by Rayleigh's term. This system is additional forced by two unbalanced identical direct current motors with limited power (non-ideal excitations). The present work mathematically implements the parametric excitation described by two periodically changing stiffness of Mathieu type that are switched on/off. Copyright © 2005 by ASME.

Automatic system for thermal damage detection in manufacturing process with Internet monitoring

This work involved the development of a smart system dedicated to surface burning detection in the grinding process through constant monitoring of the process by acoustic emission and electrical power signals. A program in Visual Basic® for Windows® was developed, which collects the signals through an analog-digital converter and further processes them using burning detection algorithms already known. Three other parameters are proposed here and a comparative study carried out. When burning occurs, the newly developed software program sends a control signal warning the operator or interrupting the process, and delivers process information via the Internet. Parallel to this, the user can also interfere in the process via Internet, changing parameters and/or monitoring the grinding process. The findings of a comparative study of the various parameters are also discussed here. Copyright © 2006 by ABCM.

Education and knowledge: basic pillars of changing production patterns with social equity

Includes bibliography

Impacts of enemy-mediated effects and the additivity of interactions in an insect trophic system

In this study, we used data from both experiments and mathematical simulations to analyze the consequences of the interacting effects of intraguild predation (IGP), cannibalism and parasitism occurring in isolation and simultaneously in trophic interactions involving two blowfly species under shared parasitism. We conducted experiments to determine the short-term response of two blowfly species to these interactions with respect to their persistence. A mathematical model was employed to extend the results obtained from these experiments to the long-term consequences of these interactions for the persistence of the blowfly species. Our experimental results revealed that IGP attenuated the strength of the effects of cannibalism and parasitism between blowfly host species, increasing the probability of persistence of both populations. The simulations obtained from the mathematical model indicated that IGP is a key interaction for the long-term dynamics of this system. The presence of different species interacting in a tri-trophic system relaxed the severity of the effects of a particular interaction between two species, changing species abundances and promoting persistence through time. This pattern was related to indirect interactions with a third species, the parasitoid species included in this study. © 2012 The Society of Population Ecology and Springer Japan.

Pervasive transition of the Brazilian land-use system

Agriculture, deforestation, greenhouse gas emissions and local/regional climate change have been closely intertwined in Brazil. Recent studies show that this relationship has been changing since the mid 2000s, with the burgeoning intensification and commoditization of Brazilian agriculture. On one hand, this accrues considerable environmental dividends including a pronounced reduction in deforestation (which is becoming decoupled from agricultural production), resulting in a decrease of similar to 40% in nationwide greenhouse gas emissions since 2005, and a potential cooling of the climate at the local scale. On the other hand, these changes in the land-use system further reinforce the long-established inequality in land ownership, contributing to rural-urban migration that ultimately fuels haphazard expansion of urban areas. We argue that strong enforcement of sector-oriented policies and solving long-standing land tenure problems, rather than simply waiting for market self-regulation, are key steps to buffer the detrimental effects of agricultural intensification at the forefront of a sustainable pathway for land use in Brazil.