Survey Of Experiments Research Articles

A Survey of Universal Basic Income Experiments

Abstract Interest in universal basic income has risen recently as an alternative to existing exchequer-sourced social security methods, such as conditional cash transfers. This article presents a survey of multiple experiments investigating the impact of basic income cash transfers on recipients while presenting a meta-analysis of the results across nine categories. Many findings indicate successful outcomes across financial security, health, and educational dimensions. Children were amongst the strongest beneficiaries of the trials and observed a 4.5 % reduction in obesity, a 19.5 % increase in their normal weight-for-age, a 30 % increase in female secondary school attendance, and an increase in the educational attainment of one year in response to the cash transfers.

Revisiting aliasing noise to build more robust sparsity in nonuniform sampling 2D-NMR.

A continuing priority is to better understand and resolve the barriers to using nonuniform sampling (NUS) in challenging small molecule 2D NMR with subsampling of the Nyquist grid (a.k.a. coverage) below 50%. Possible causes for artifacts, often termed sampling noise, in 1D-NUS of 2D-NMR are revisited here, where weak aliasing artifacts are a growing concern as NUS becomes sparser. As NUS schedules become sparser, repeat sequences are shown to occur in the dense sampling regions early in the sampling schedule, causing aliasing artifacts in resulting spectra. An intuitive screening approach that detects patterns in sampling schedules based on a convolutional filter was implemented. Sampling schedules that have low proportions of repeat sequences show significantly reduced artifacts. Another route to remediate early repeat sequences is a short period of uniform sampling at the beginning of the schedule, which also leads to a significant suppression of unwanted sampling noise. Combining the repeat sequence filter with a survey of HSQC and LR-HSQMBC experiments, it is shown that very short initial uniform regions of about 2%-4% of the sampling space can ameliorate repeat sequences in sparser NUS and lead to robust spectral reconstructions by iterative soft thresholding (IST), even when the point spread function is unchanged. Using the principles developed here, a suite of 'one-click' schedules was developed for broader use.

Redox Switches in Noise-Induced Cardiovascular and Neuronal Dysregulation.

Environmental exposures represent a significant health hazard, which cumulatively may be responsible for up to 2/3 of all chronic non-communicable disease and associated mortality (Global Burden of Disease Study and The Lancet Commission on Pollution and Health), which has given rise to a new concept of the exposome: the sum of environmental factors in every individual’s experience. Noise is part of the exposome and is increasingly being investigated as a health risk factor impacting neurological, cardiometabolic, endocrine, and immune health. Beyond the well-characterized effects of high-intensity noise on cochlear damage, noise is relatively well-studied in the cardiovascular field, where evidence is emerging from both human and translational experiments that noise from traffic-related sources could represent a risk factor for hypertension, ischemic heart disease, diabetes, and atherosclerosis. In the present review, we comprehensively discuss the current state of knowledge in the field of noise research. We give a brief survey of the literature documenting experiments in noise exposure in both humans and animals with a focus on cardiovascular disease. We also discuss the mechanisms that have been uncovered in recent years that describe how exposure to noise affects physiological homeostasis, leading to aberrant redox signaling resulting in metabolic and immune consequences, both of which have considerable impact on cardiovascular health. Additionally, we discuss the molecular pathways of redox involvement in the stress responses to noise and how they manifest in disruptions of the circadian rhythm, inflammatory signaling, gut microbiome composition, epigenetic landscape and vessel function.

Effects of Synonymous Mutations beyond Codon Bias: The Evidence for Adaptive Synonymous Substitutions from Microbial Evolution Experiments.

Synonymous mutations are often assumed to be neutral with respect to fitness because they do not alter the encoded amino acid and so cannot be “seen” by natural selection. Yet a growing body of evidence suggests that synonymous mutations can have fitness effects that drive adaptive evolution through their impacts on gene expression and protein folding. Here, we review what microbial experiments have taught us about the contribution of synonymous mutations to adaptation. A survey of site-directed mutagenesis experiments reveals the distributions of fitness effects for nonsynonymous and synonymous mutations are more similar, especially for beneficial mutations, than expected if all synonymous mutations were neutral, suggesting they should drive adaptive evolution more often than is typically observed. A review of experimental evolution studies where synonymous mutations have contributed to adaptation shows they can impact fitness through a range of mechanisms including the creation of illicit RNA polymerase binding sites impacting transcription and changes to mRNA folding stability that modulate translation. We suggest that clonal interference in evolving microbial populations may be the reason synonymous mutations play a smaller role in adaptive evolution than expected based on their observed fitness effects. We finish by discussing the impacts of falsely assuming synonymous mutations are neutral and discuss directions for future work exploring the role of synonymous mutations in adaptive evolution.

Designing chemical micromotors that communicate-A survey of experiments

Micromotors that communicate with their neighbors or with the environment are useful in a wide variety of applications, especially those involving complicated tasks that require coordination. A biomimetic strategy for achieving this goal is via chemical communication, where chemical signals released from one motor is transmitted through the medium and induce a specific response from a second motor. In this article, we review the recent experimental progress on this front. We first introduce three common strategies for releasing chemicals from a microscopic object, via diffusion, physical/chemical stimuli, or gated control, that form the cornerstone for designing communicating micromotors. We then review three levels of chemical communication of micromotors in order of ascending complexity, starting with cases where micromotors attract or repel inert tracers, to the unidirectional signal transmission between two motors of different types, and finally to the reciprocal (bidirectional) communication between two motors that often lead to higher-order assemblies. This review article ends with a perspective of the challenges and opportunities with communicating micromotors, which could inspire more sophisticated designs of in-depth communication between motors with different functions.

Adaptation to elevation but limited local adaptation in an amphibian.

We performed a reciprocal transplant experiment to estimate "parallel" adaptation to elevation and "unique" adaptation to local sites at the same elevation, using the frog Rana temporaria in the Swiss Alps. It is important to distinguish these two processes because they have different implications for population structure and ecological specialization. Larvae were reared from hatching to metamorphosis within enclosures installed in their pond of origin, in three foreign ponds at the same elevation, and in four ponds at different elevation (1500-2000 m higher or lower). There were two source populations from each elevation, and adults were held in a common environment for 1 year before they were crossed to produce offspring for the experiment. Fitness was a measure that integrated larval survival, development rate, and body size. Parallel adaptation to elevation was indicated by an advantage at the home elevation (11.5% fitness difference at low elevation and 47% at high elevation). This effect was stronger than that observed in most other studies, according to a survey of previous transplant experiments across elevation (N = 8 animal species and 71 plants). Unique local adaptation within elevational zones was only 0.3-0.7 times as strong as parallel adaptation, probably because gene flow is comparatively high among nearby wetlands at the same elevation. The home-elevation advantage may reduce gene flow across the elevational gradient and enable the evolution of habitat races specialized on elevation.

(RE)SIGNIFICADOS DAS CIÊNCIAS BIOLÓGICAS: ANÁLISE DO PROCESSO DE SEMIOSE DO CONCEITO DE CAMUFLAGEM EM DESENHOS ANIMADOS

Este trabalho busca responder como ocorre a (re)significação de conceitos e termos relacionados a ciência na linguagem da animação, com intuito de evidenciar quais elementos simbólicos os desenhos animados utilizam para representar os conceitos científicos das ciências biológicas. Para tanto, desenvolveu-se uma pesquisa qualitativa em que se realizou análise semiótica de desenhos animados, tais como “Show da Luna”, “Aventuras com os Kratts” e “Natugato”, ancorada na teoria Peirciana. Conjectura-se que a relevância deste estudo provém da possibilidade de compreensão do processo de semiose que ocorre entre os signos analisados (desenhos animados e material acadêmico). Considera-se a possibilidade da utilização dos desenhos animados com temáticas científicas como recurso não formal para a popularização das ciências, que ao receber um olhar crítico, pode ser utilizado como ferramenta pedagógica. De acordo com os resultados, percebeu-se que os episódios analisados podem ser considerados como recurso que apresenta aspectos próprios da ciência, de maneira simples e clara.Observou-se uma ressignifiação da linguagem científica para a do entretenimento, o uso e a presença de alguns símbolos característicos da Biologia em todos os episódios. Além disso, verificou-se que os elementos caracteríticos da animação (som, música, repetição e transição de imagens, zoom-in e zoom-out) são utilizados tanto para marcar as etapas do trabalho científico (elaboração do problema, levantamento de hipoteses, testes e experimentos, possível explicação/solução do problema, conclusão e divulgação das conclusões), quanto na apresentação dos conceitos e fenômenos da Biologia. Em geral os conceitos de Biologia abordados nesses episódios estão em consonância com o material acadêmico comparado.

Hunt for sub-GeV dark matter at neutrino facilities: A survey of past and present experiments

We survey the sensitivity of past and present neutrino experiments to MeV-GeV scale dark matter, and find that these experiments possess novel sensitivity that has not yet fully explored. NO$\nu$A and BEBC are found to rule out the scalar thermal target for dark matter masses between 10 MeV to 100 MeV with existing data, while CHARM-II and MINER$\nu$A place somewhat weaker limits. These limits can be dramatically improved by off-axis searches using the NuMI beamline and the MicroBooNE, MiniBooNE or ICARUS detectors, and can even begin to probe the Majorana thermal target. We conclude that past and present neutrino facilities can search for light dark matter concurrently with their neutrino program and reach a competitive sensitivity to proposed future experiments.

From signals to knowledge: A conceptual model for multimodal learning analytics

AbstractMultimodality in learning analytics and learning science is under the spotlight. The landscape of sensors and wearable trackers that can be used for learning support is evolving rapidly, as well as data collection and analysis methods. Multimodal data can now be collected and processed in real time at an unprecedented scale. With sensors, it is possible to capture observable events of the learning process such as learner's behaviour and the learning context. The learning process, however, consists also of latent attributes, such as the learner's cognitions or emotions. These attributes are unobservable to sensors and need to be elicited by human‐driven interpretations. We conducted a literature survey of experiments using multimodal data to frame the young research field of multimodal learning analytics. The survey explored the multimodal data used in related studies (the input space) and the learning theories selected (the hypothesis space). The survey led to the formulation of the Multimodal Learning Analytics Model whose main objectives are of (O1) mapping the use of multimodal data to enhance the feedback in a learning context; (O2) showing how to combine machine learning with multimodal data; and (O3) aligning the terminology used in the field of machine learning and learning science.

Comparison of runaway electron generation parameters in small, medium-sized and large tokamaks—A survey of experiments in COMPASS, TCV, ASDEX-Upgrade and JET

This paper presents a survey of the experiments on runaway electrons (RE) carried out recently in frames of EUROFusion Consortium in different tokamaks: COMPASS, ASDEX-Upgrade, TCV and JET. Massive gas injection (MGI) has been used in different scenarios for RE generation in small and medium-sized tokamaks to elaborate the most efficient and reliable ones for future RE experiments. New data on RE generated at disruptions in COMPASS and ASDEX-Upgrade was collected and added to the JET database. Different accessible parameters of disruptions, such as current quench rate, conversion rate of plasma current into runaways, etc have been analysed for each tokamak and compared to JET data. It was shown, that tokamaks with larger geometrical sizes provide the wider limits for spatial and temporal variation of plasma parameters during disruptions, thus extending the parameter space for RE generation. The second part of experiments was dedicated to study of RE generation in stationary discharges in COMPASS, TCV and JET. Injection of Ne/Ar have been used to mock-up the JET MGI runaway suppression experiments. Secondary RE avalanching was identified and quantified for the first time in the TCV tokamak in RE generating discharges after massive Ne injection. Simulations of the primary RE generation and secondary avalanching dynamics in stationary discharges has demonstrated that RE current fraction created via avalanching could achieve up to 70–75% of the total plasma current in TCV. Relaxations which are reminiscent the phenomena associated to the kinetic instability driven by RE have been detected in RE discharges in TCV. Macroscopic parameters of RE dominating discharges in TCV before and after onset of the instability fit well to the empirical instability criterion, which was established in the early tokamaks and examined by results of recent numerical simulations.

The Economics of Credence Goods – a Survey of Recent Lab and Field Experiments*

Many important markets, such as those for health care or repair services, are characterized by pronounced informational asymmetries between buyers and sellers – because the buyer cannot identify the quality of the product that fits her needs best, while the seller can do so by performing a diagnosis. The seller can then recommend the appropriate or an inappropriate quality. Since the buyer has no means to verify the correctness of the recommendation but has to rely on the honesty of the seller, such goods are called credence goods. Markets for credence goods are typically plagued by incentives for fraudulent behavior and by inefficiencies caused by actual or expected fraud, covering overprovision and overcharging. Although highly policy relevant, a carefully controlled analysis of the provision of credence goods through the use of experiments has only recently taken off. Here, we provide an overview about recent laboratory and field experiments on the economics of credence goods and discuss important implications and directions for future research.

Synthesis of superheavy elements at the Dubna gas-filled recoil separator

A survey of experiments at the Dubna gas-filled recoil separator (Laboratory of Nuclear Reactions, JINR, Dubna) aimed at the detection and study of the “island of stability” of superheavy nuclei produced in complete fusion reactions of 48Са ions and 238U–249Cf target nuclei is given. The problems of synthesis of superheavy nuclei, methods for their identification, and investigation of their decay properties, including the results of recent experiments at other separators (SHIP, BGS, TASCA) and chemical setups, are discussed. The studied properties of the new nuclei, the isotopes of elements 112–118, as well as the properties of their decay products, indicate substantial growth of stability of the heaviest nuclei with increasing number of neutrons in the nucleus as the magic number of neutrons N = 184 is approached.

On the interest of microgravity experimentation for studying convective effects during the directional solidification of metal alloys

Under terrestrial conditions, solidification processes are often affected by gravity effects, which can significantly influence the final characteristics of the grown solid. The low-gravity environment of space offers a unique and efficient way to eliminate these effects, providing valuable benchmark data for the validation of models and numerical simulations. Moreover, a comparative study of solidification experiments on earth and in low-gravity conditions can significantly enlighten gravity effects. The aim of this paper is to give a survey of solidification experiments conducted in low-gravity environment on metal alloys, with advanced post-mortem analysis and eventually by in situ and real-time characterization.

Communicative and Artistic Machines: A Survey of Models and Experiments on Artificial Agents

Communicative and Artistic Machines: A Survey of Models and Experiments on Artificial Agents

Emergent gauge fields and the high-temperature superconductors.

The quantum entanglement of many states of matter can be represented by electric and magnetic fields, much like those found in Maxwell's theory. These fields 'emerge' from the quantum structure of the many-electron state, rather than being fundamental degrees of freedom of the vacuum. I review basic aspects of the theory of emergent gauge fields in insulators in an intuitive manner. In metals, Fermi liquid (FL) theory relies on adiabatic continuity from the free electron state, and its central consequence is the existence of long-lived electron-like quasi-particles around a Fermi surface enclosing a volume determined by the total density of electrons, via the Luttinger theorem. However, long-range entanglement and emergent gauge fields can also be present in metals. I focus on the 'fractionalized Fermi liquid' (FL*) state, which also has long-lived electron-like quasi-particles around a Fermi surface; however, the Luttinger theorem on the Fermi volume is violated, and this requires the presence of emergent gauge fields, and the associated loss of adiabatic continuity with the free electron state. Finally, I present a brief survey of some recent experiments in the hole-doped cuprate superconductors, and interpret the properties of the pseudogap regime in the framework of the FL* theory.This article is part of the themed issue 'Unifying physics and technology in light of Maxwell's equations'.

The Impact of Behavioral Science Experiments on Energy Policy

One of the most exciting areas of research today is the use of experiments informed by behavioral science to understand how to change energy consumption decisions of consumers. This article provides a survey and synthesis of experiments and focuses on general principles that can be gleaned from these experiments to date. We identify four general insights from the literature. First, the law of demand is typically satisfied in experimental settings, but responsiveness to energy price changes can vary dramatically in different contexts. Second, information provision can help promote reductions in energy use, but it does not always work. Third, the use of social norms can change energy use. Finally, the economic welfare impacts of behavioral interventions aimed at promoting either energy conservation or energy efficiency are not well understood, but initial research suggests that some people want nudges and some do not. The essay also identifies a number of areas for future research.

Aluminum particle combustion in turbulent flames

Predictive mechanisms for particle ignition and combustion rates are required in order to develop optimized propellant and energetic formulations using micron-sized metal powders, such as aluminum. Most current descriptions are based on laboratory experiments performed in stationary or laminar combustion configurations. However, turbulent environments exist in most applications and validity of the present descriptions for such environments has not been established. This experimental study is aimed to measure burn times for aluminum particles burning in environments with different levels of turbulence. A laminar air-acetylene flame is produced, and auxiliary tangential jets of air with adjustable flow rates are used to achieve different controlled levels of turbulence. Fine spherical aluminum powder is injected in the flame axially using a flow of nitrogen. The streaks of burning particles are photographed using a camera placed behind a mechanical chopper interrupting the photo-exposure with a pre-set frequency. The obtained dashed streaks are used to measure the particle burn times for different flow conditions. The particle burn times are correlated with the particle size distribution to obtain the burn time as a function of the particle size. The results are processed to obtain a correction for the Al particle burn rate as a function of the turbulence intensity, I. The measured burn times are longer than predicted for the micron-sized Al particles using a correlation based on survey of earlier experiments, mostly with coarser Al powders. Increased turbulence intensity results in substantial reduction of the particle burn time. Present data suggest that the burn rate for particle combustion in a laminar environment should be multiplied by 1+18.2I, to estimate the acceleration of aluminum combustion in turbulent environments.

A survey of urban climate change experiments in 100 cities

Cities are key sites where climate change is being addressed. Previous research has largely overlooked the multiplicity of climate change responses emerging outside formal contexts of decision-making and led by actors other than municipal governments. Moreover, existing research has largely focused on case studies of climate change mitigation in developed economies. The objective of this paper is to uncover the heterogeneous mix of actors, settings, governance arrangements and technologies involved in the governance of climate change in cities in different parts of the world.The paper focuses on urban climate change governance as a process of experimentation. Climate change experiments are presented here as interventions to try out new ideas and methods in the context of future uncertainties. They serve to understand how interventions work in practice, in new contexts where they are thought of as innovative. To study experimentation, the paper presents evidence from the analysis of a database of 627 urban climate change experiments in a sample of 100 global cities.The analysis suggests that, since 2005, experimentation is a feature of urban responses to climate change across different world regions and multiple sectors. Although experimentation does not appear to be related to particular kinds of urban economic and social conditions, some of its core features are visible. For example, experimentation tends to focus on energy. Also, both social and technical forms of experimentation are visible, but technical experimentation is more common in urban infrastructure systems. While municipal governments have a critical role in climate change experimentation, they often act alongside other actors and in a variety of forms of partnership. These findings point at experimentation as a key tool to open up new political spaces for governing climate change in the city.

Deposition ofCryptosporidium parvumOocysts in Porous Media: A Synthesis of Attachment Efficiencies Measured under Varying Environmental Conditions

An extensive set of column experiments was performed with freshly harvested Cryptosporidium parvum oocysts to evaluate the effects of solution chemistry, surface coatings, interactions with other suspended particles, and pore fluid velocity on the fate and transport of this widely occurring waterborne pathogen in sandy porous media. We synthesized our data set with a comprehensive literature survey of similar experiments, to compute attachment (collision) efficiencies (α) used in colloid filtration theory (CFT) using three models for the single collector efficiency (η) across a wide range of experimental conditions. Most prior experiments have observed the transport of surface-treated, sterile C. parvum oocyst in porous media. Our column data confirm for freshly harvested oocysts that the presence of iron coatings on the sand medium and the presence of suspended illite clay drastically enhance oocyst deposition. Increasing ionic strength and decreasing pH also systematically enhance the attachment efficiency. Attachment efficiency decreases only at a very high ionic strength, most likely as a result of steric repulsion and possibly other changes in oocyst surface properties. Attachment efficiencies vary with fluid flow rate but without showing specific trends. We found that the computed attachment efficiency across all reported experiments could be reliably estimated using a regression model based on parameters related to ionic strength and pH. The regression model performed better with the Nelson-Ginn η model and Tufenkji-Elimelech η model than with the Rajagopalan-Tien η model. When CFT is used in environmental assessments, the proposed regression model provides a practical estimator for attachment efficiencies of C. parvum oocyst deposition in porous media for a variety of environmental conditions unfavorable to attachment.

Who Eats Whom in a Pool? A Comparative Study of Prey Selectivity by Predatory Aquatic Insects

Predatory aquatic insects are a diverse group comprising top predators in small fishless water bodies. Knowledge of their diet composition is fragmentary, which hinders the understanding of mechanisms maintaining their high local diversity and of their impacts on local food web structure and dynamics. We conducted multiple-choice predation experiments using nine common species of predatory aquatic insects, including adult and larval Coleoptera, adult Heteroptera and larval Odonata, and complemented them with literature survey of similar experiments. All predators in our experiments fed selectively on the seven prey species offered, and vulnerability to predation varied strongly between the prey. The predators most often preferred dipteran larvae; previous studies further reported preferences for cladocerans. Diet overlaps between all predator pairs and predator overlaps between all prey pairs were non-zero. Modularity analysis separated all primarily nectonic predator and prey species from two groups of large and small benthic predators and their prey. These results, together with limited evidence from the literature, suggest a highly interconnected food web with several modules, in which similarly sized predators from the same microhabitat are likely to compete strongly for resources in the field (observed Pianka’s diet overlap indices >0.85). Our experiments further imply that ontogenetic diet shifts are common in predatory aquatic insects, although we observed higher diet overlaps than previously reported. Hence, individuals may or may not shift between food web modules during ontogeny.