Current status of turbulent dynamo theory: From large-scale to small-scale dynamos

Several recent advances in turbulent dynamo theory are reviewed. High resolution simulations of small-scale and large-scale dynamo action in periodic domains are compared with each other and contrasted with similar results at low magnetic Prandtl numbers. It is argued that all the different cases show similarities at intermediate length scales. On the other hand, in the presence of helicity of the turbulence, power develops on large scales, which is not present in non-helical small-scale turbulent dynamos. At small length scales, differences occur in connection with the dissipation cutoff scales associated with the respective value of the magnetic Prandtl number. These differences are found to be independent of whether or not there is large-scale dynamo action. However, large-scale dynamos in homogeneous systems are shown to suffer from resistive slow-down even at intermediate length scales. The results from simulations are connected to mean field theory and its applications. Recent work on helicity fluxes to alleviate large-scale dynamo quenching, shear dynamos, nonlocal effects and magnetic structures from strong density stratification are highlighted. Several insights which arise from analytic considerations of small-scale dynamos are discussed.Comment: 36 pages, 11 figures, Spa. Sci. Rev., submitted to the special issue "Magnetism in the Universe" (ed. A. Balogh

Quantum Griffiths effects and smeared phase transitions in metals: theory and experiment

In this paper, we review theoretical and experimental research on rare region effects at quantum phase transitions in disordered itinerant electron systems. After summarizing a few basic concepts about phase transitions in the presence of quenched randomness, we introduce the idea of rare regions and discuss their importance. We then analyze in detail the different phenomena that can arise at magnetic quantum phase transitions in disordered metals, including quantum Griffiths singularities, smeared phase transitions, and cluster-glass formation. For each scenario, we discuss the resulting phase diagram and summarize the behavior of various observables. We then review several recent experiments that provide examples of these rare region phenomena. We conclude by discussing limitations of current approaches and open questions.Comment: 31 pages, 7 eps figures included, v2: discussion of the dissipative Ising chain fixed, references added, v3: final version as publishe

GoalD: A Goal-Driven Deployment Framework for Dynamic and Heterogeneous Computing Environments

Context: Emerging paradigms like Internet of Things and Smart Cities utilize advanced sensing and communication infrastructures, where heterogeneity is an inherited feature. Applications targeting such environments require adaptability and context-sensitivity to uncertain availability and failures in resources and their ad-hoc networks. Such heterogeneity is often hard to predict, making the deployment process a challenging task. Objective: This paper proposes GoalD as a goal-driven framework to support autonomous deployment of heterogeneous computational resources to fulfill requirements, seen as goals, and their correlated components on one hand, and the variability space of the hosting computing and sensing environment on the other hand. Method: GoalD comprises an offline and an online stage to fulfill autonomous deployment by leveraging the use of goals. Deployment configuration strategies arise from the variability structure of the Contextual Goal Model as an underlying structure to guide autonomous planning by selecting available as well as suitable resources at runtime. Results: We evaluate GoalD on an existing exemplar from the selfadaptive systems community – the Tele Assistance Service provided by Weyns and Calinescu [1]. Furthermore, we evaluate the scalability of GoalD on a repository consisting of 430,500 artifacts. The evaluation results demonstrate the usefulness and scalability of GoalD in planning the deployment of a system with thousands of components in a few milliseconds

Analysis of environmental conditions and management in a compost-bedded pack barn with tunnel ventilation

Received: January 5th, 2021 ; Accepted: March 27th, 2021 ; Published: April 16th, 2021 ; Correspondence: [email protected] housing system based on compost-bedded pack for dairy cows is spreading rapidly in Brazil. Completely open buildings without curtains and simple roofs are usually provided. However, in the last years some new completely closed barns have been realized. This study aims to analyse one of these closed barns, located in the State of Minas Gerais. The two main sides of the facility are provided with polyethylene curtains of blue colour and five deflectors. The barn is equipped with an evaporative adiabatic cooling system, associated with the tunnel-style ventilation, realized with exhaust fans, continuously operating 24 hours a day. 85 lactating Holstein cows were housed in the barn during the trials carried out in the winter season 2019. Microclimatic data were collected continuously. Air speed, illuminance and bedding temperature were measured during the farm visits. Pack moisture was calculated. The results state the importance of bedding management and climatic conditions inside the barn. It emerges that the cows housed in this kind of closed barn, with forced ventilation, are in good thermal conditions, which are fairly constant. The average illumination of the barn can be considered acceptable (55.06 lx), even if some areas of the barn present values below the minimum ones reported in literature. The bedding temperature varies between a maximum of 36.33 °C and a minimum of 25.44 °C with an average of 31.26 °C. The values of bedding moisture are between a maximum of 64.36% and a minimum of 60.81% with an average of 62.48%

Laparotomy

Celiotomia, que significa precisamente incisão da parede abdominal em qualquer região, é considerado sinônimo de laparotomia, cuja acepção exata é "secção do flanco".  A abertura da cavidade abdominal para fins diagnósticos e terapêuticos remonta a antiguidade, mas tornou-se rotineira a partir dosmeados do século XX com o advento da anestesia geral, utilizando drogas curarizantes e entubaçãoorotraqueal.  Serão discutidos a classificação das laparotomias quanto a finalidade, direção, a complexidade e a relação com estruturas da parede abdominal.Celiotomy, which precisely means incision of any region of the abdominal wall, is considered a synonymof laparotomy, whose exact definition is 'section of the flank'. Opening of the abdominal cavity for diagnostic and therapeutic purposes dates back to ancient times, but it became a routine procedure in the midtwentieth century with the advent of general anesthesia, by means of curaric agents and orotrachealintubation. We will discuss the classification of laparotomies according to their purposes, direction,complexity, and relation with abdominal wall structures

Willingness to pay for quality traits and implications for sweetpotato variety breeding: case of Mozambique

Despite decades of research and dissemination of improved sweetpotato varieties, uptake at scale remains low and envisaged development goals of food security and livelihoods remain elusive. This is despite demonstrated impacts of such technologies in combating food and nutrition insecurity, amidst global challenges like climate change. Growing evidence show that end-user acceptance of improved varieties is critical in the widespread adoption of such varieties, and inclusion of the heterogenous preferences of diverse sets of end-users in the variety development process is therefore critical. With global changes in weather and consumption patterns, end-users are now demanding varieties that are more suitable to their unique consumption needs, production environments, new market demands and have desired processing characteristics. Such dynamics in demand have necessitated rethinking of breeding programs from the traditional focus on agronomic gains such as increase in yields and yield protection, to consideration of more nuanced quality-related traits that appeal to targeted populations. Against this background, this study sets out to explore the decision-making behavior of Mozambican sweetpotato producers in variety selection, and the implicit value placed on different sweetpotato traits, including the often ignored but crucial quality traits. The aim of the study is to identify the economic valuation of such traits and how they are traded off in variety selection decisions, to allow for prioritization in breeding efforts. To achieve this, an exploratory sequential design in a predominantly quantitative mixed-method design was adopted for the study. First, based on the insights from a gender disaggregated qualitative assessment among sweetpotato growers and consumers and in consultation with breeding experts from Mozambique, the most preferred sweetpotato variety traits in the regions of study were established. These traits were then utilized in the design of a choice experiment, implemented among 860 sweetpotato producers spread across four sweetpotato growing regions in the country. Finally, a generalized multinomial logit model was used to estimate implicit economic valuation of each of the considered trait, as well as heterogenous valuation of such traits across gender, education and age of respondent groups. Results from the study show that producers have a high preference for quality-related traits, with preference for Vitamin A being higher than that for drought tolerance, while dry matter content is valued about the same as drought tolerance. While scoring significantly lower than Vitamin A, drought tolerance and dry matter content, other quality-related traits like root size and sweet taste also have significant positive values implying their importance in informing sweetpotato variety choice. In terms of gender heterogeneity, flesh color is highly valued among the women sub-sample. The study identifies Vitamin A, dry matter content, sweet taste, and medium to big root size, as the key preferred quality traits in Mozambique, in that order. The results imply that these quality traits should be pursued as a suite in breeding objectives, in combination with essential agronomic traits such as high yields and drought tolerance, for higher acceptance and demand of improved sweetpotato varieties across the country