Unique Regime Research Articles

Development of an inertial confinement fusion platform to study charged-particle-producing nuclear reactions relevant to nuclear astrophysics

This paper describes the development of a platform to study astrophysically relevant nuclear reactions using inertial-confinement fusion implosions on the OMEGA and National Ignition Facility laser facilities, with a particular focus on optimizing the implosions to study charged-particle-producing reactions. Primary requirements on the platform are high yield, for high statistics in the fusion product measurements, combined with low areal density, to allow the charged fusion products to escape. This is optimally achieved with direct-drive exploding pusher implosions using thin-glass-shell capsules. Mitigation strategies to eliminate a possible target sheath potential which would accelerate the emitted ions are discussed. The potential impact of kinetic effects on the implosions is also considered. The platform is initially employed to study the complementary T(t,2n)α, T(3He,np)α and 3He(3He,2p)α reactions. Proof-of-principle results from the first experiments demonstrating the ability to accurately measure the energy and yields of charged particles are presented. Lessons learned from these experiments will be used in studies of other reactions. The goals are to explore thermonuclear reaction rates and fundamental nuclear physics in stellar-like plasma environments, and to push this new frontier of nuclear astrophysics into unique regimes not reachable through existing platforms, with thermal ion velocity distributions, plasma screening, and low reactant energies.

Spatiotemporal patterns of paralytic shellfish toxins and their relationships with environmental variables in British Columbia, Canada from 2002 to 2012

BackgroundHarmful algal blooms produce paralytic shellfish toxins that accumulate in the tissues of filter feeding shellfish. Ingestion of these toxic shellfish can cause a serious and potentially fatal condition known as paralytic shellfish poisoning (PSP). The coast of British Columbia is routinely monitored for shellfish toxicity, and this study uses data from the monitoring program to identify spatiotemporal patterns in shellfish toxicity events and their relationships with environmental variables. MethodsThe dinoflagellate genus Alexandrium produces the most potent paralytic shellfish toxin, saxitoxin (STX). Data on all STX measurements were obtained from 49 different shellfish monitoring sites along the coast of British Columbia for 2002–2012, and monthly toxicity events were identified. We performed hierarchical cluster analysis to group sites that had events in similar areas with similar timing. Machine learning techniques were used to model the complex relationships between toxicity events and environmental variables in each group. ResultsThe Strait of Georgia and the west coast of Vancouver Island had unique toxicity regimes. Out of the seven environmental variables used, toxicity in each cluster could be described by multivariable models including monthly sea surface temperature, air temperature, sea surface salinity, freshwater discharge, upwelling, and photosynthetically active radiation. The sea surface salinity and freshwater discharge variables produced the strongest univariate models for both geographic areas. ConclusionsApplying these methods in coastal regions could allow for the prediction of shellfish toxicity events by environmental conditions. This has the potential to optimize biotoxin monitoring, improve public health surveillance, and engage the shellfish industry in helping to reduce the risk of PSP.

Trust or Legal Person: A Brief Review of the Organizational Features of Western Political Thoughts

Trust law as a unique legal regime in common law world has deeply influenced the legal and political practices in Anglo-American legal system. By contrast, the regime of legal person formed a series of distinctive legal theories and political practices in Continental jurisdictions. From the perspective of organizational law, this essay explores the different governance mechanisms of Anglo-American constitutionalism and Continental political traditions, and re-explains why historically the common law countries have advantages in democratic politics.

A gyrokinetic perspective on the JET-ILW pedestal

JET has been unable to recover historical confinement levels when operating with an ITER-like wall (ILW) due largely to the inaccessibility of high pedestal temperatures. Finding a path to overcome this challenge is of utmost importance for both a prospective JET DT campaign and for future ITER operation. Gyrokinetic simulations (using the Gene code) quantitatively capture experimental transport levels for a representative experimental discharge and qualitatively recover the major experimental trends. Microtearing turbulence is a major transport mechanisms for the low-temperature pedestals characteristic of unseeded JET-ILW discharges. At higher temperatures and/or lower , we identify electrostatic ITG transport of a type that is strongly shear-suppressed on smaller machines. Consistent with observations, this transport mechanism is strongly reduced by the presence of a low-Z impurity (e.g. carbon or nitrogen at the level of ), recovering the accessibility of high pedestal temperatures. Notably, simulations based on dimensionless scans recover historical scaling behavior except in the unique JET-ILW parameter regime where ITG turbulence becomes important. Our simulations also elucidate the observed degradation of confinement caused by gas puffing, emphasizing the important role of the density pedestal structure. This study maps out important regions of parameter space, providing insights that may point to optimal physical regimes that can enable the recovery of high pedestal temperatures on JET.

Do remittances not promote growth? A finite mixture-of-regressions approach

This paper re-examines the impact of remittance inflows on growth using data for developing countries over the period 1970–2010. We relax the hypothesis that all countries follow the same unique growth regime in favor of multiple regimes, and test whether the impact of remittances on growth depends on the growth regime to which an economy belongs. We follow the recent literature that has applied the finite-mixture-of-regressions method in other circumstances to endogenously identify growth regimes, correcting for unobserved heterogeneity. We find that our data are best described by an econometric model with two different growth regimes: one in which remittances have a positive and significant marginal impact on growth; and another in which the impact of remittances is insignificant. The analysis of the determinants of the probability of being in the remittances growth-enhancing regime shows that being a Sub-Saharan African country increases significantly this probability, while financial development moderately reduces this probability but with strong reservations on the statistical significance of the estimates on the different indicators of financial development.

Migration and regional inequality: changing characteristics of China’s economic inequality

Scholars studying economic inequality in China have maintained that regional inequality and economic divergence across provinces have steadily increased over the past 30 years. New studies have shown that this trend is a statistical aberration; calculations show that instead of quickly and sharply rising, regional inequality has actually decreased, and most recently, remained stable. Our study suggests that China’s unique migratory regime is crucial to understanding these findings. We conduct a counterfactual simulation to demonstrate how migration and remittances have mitigated income inequality across provinces in order to show that without these processes, we would have seen more of a rise in interprovincial income inequality. We conclude by arguing that inequality in China is still increasing, but it is changing and becoming less place-based. As regional inequality decreases, there are signs that point to the increasing importance of interpersonal inequality.

Do prior diel thermal cycles influence the physiological response of Atlantic salmon (Salmo salar) to subsequent heat stress?

We designed two environmentally relevant thermal cycling regimes using monitoring data from an Atlantic salmon (Salmo salar) river to determine whether exposure to prior diel cycles stimulated protective mechanisms (e.g., heat hardening) and (or) resulted in physiological and cellular stress. Wild fish were exposed to 3 days of diel cycling in the lab and then exposed to an acute thermal challenge near their upper reported critical temperature. We measured routine metabolic rate across the time course as well as indicators of physiological status (e.g., plasma glucose and osmolality) and cellular stress (e.g., heat shock protein 70). We observed that thermal cycling altered physiological and cellular responses, compared with an acute heat shock, but saw no differences between cycling regimes. Unique temperature regime and tissue-specific responses were observed in heat shock protein induction, metabolites, haematology, and osmotic indicators. Routine metabolic rate was not affected by the thermal cycling and increased according to Q10predictions. While we report unique physiological and cellular responses among all treatment groups, we did not observe a clear indication of a heat hardening response.

Gross--Pitaevskii Vortex Motion with Critically Scaled Inhomogeneities

We study the dynamics of vortices in an inhomogeneous Gross-Pitaevskii equation $i \partial_t u = \Delta u + {1\over \varepsilon^2} (p_\varepsilon^2(x) - |u|^2)$. For a unique scaling regime $|p_\varepsilon(x) - 1 | = O(|\log \varepsilon|^{-1})$, it is shown that vortices can interact both with the background perturbation and with each other. Results for associated parabolic and elliptic problems are discussed.

Gross--Pitaevskii Vortex Motion with Critically Scaled Inhomogeneities

We study the dynamics of vortices in an inhomogeneous Gross--Pitaevskii equation $i \partial_t u = \Delta u + {1\over \varepsilon^2} (\rho_\varepsilon^2(x) - |u|^2)$. For a unique scaling regime $|\rho_\varepsilon(x) - 1 | = O(\log\varepsilon^{-1})$, it is shown that vortices can interact both with the background perturbation and with each other. Results for associated parabolic and elliptic problems are discussed.

水位变化对三峡库区消落带落羽杉营养特征的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 水位变化对三峡库区消落带落羽杉营养特征的影响 DOI: 10.5846/stxb201606211213 作者: 作者单位: 西南大学生命科学学院,西南大学生命科学学院,西南大学生命科学学院,西南大学生命科学学院,西南大学生命科学学院 作者简介: 通讯作者: 中图分类号: 基金项目: 国家国际科技合作专项（2015DFA90900）；三峡后续工作库区生态与生物多样性保护专项项目（5000002013BB5200002）；重庆市林业重点科技攻关项目（渝林科研2015-6）；中央财政林业科技推广示范项目（渝林科推[2014-10]）；重庆市研究生科研创新项目（CYB16066） Effect of water-level change on nutritional characteristics of Taxodium distichum in the hydro-fluctuation belt of the Three Gorges Reservoir Author: Affiliation: College of Life Science,Southwest University,College of Life Science,Southwest University,College of Life Science,Southwest University,College of Life Science,Southwest University,College of Life SCience, Southwest University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:三峡大坝建成蓄水后，其独特的水位调度节律对水库消落带植物的生境造成巨大干扰。为了解落羽杉在消落带特殊生境下的生理生态过程，探究其水淹耐受机制，在三峡库区消落带植被修复忠县示范基地建立3 a后，对试验样地内种植于消落带海拔175-165 m范围的落羽杉进行叶片、根系样品采集，并调查其生长情况，测定分析落羽杉营养元素含量及其与植株生长和土壤养分间的关系。结果表明：（1）水位变化对适生树种落羽杉营养元素吸收造成了明显影响。随着淹水深度和淹水时间的延长，落羽杉根系能量代谢受阻，根系功能紊乱，营养元素吸收与运输受到抑制，落羽杉N、P、K、Ca、Zn吸收减少；水淹导致土壤中Fe2+、Mn2+含量升高，落羽杉Fe、Mn吸收增加。（2）相关性分析表明，落羽杉株高与N、K、Mg含量呈极显著正相关关系，与P含量呈显著正相关关系，而与Fe、Cu含量呈极显著负相关关系，与Mn含量呈显著负相关关系；落羽杉冠幅与植株N、P、K、Mg含量呈极显著正相关关系，而与Fe、Cu含量呈极显著负相关关系；落羽杉营养元素含量与土壤元素含量无显著相关性。（3）消落带不同海拔落羽杉营养元素的积累量均不低于植物正常生长水平，未见严重的缺素状况。研究结果表明，落羽杉对三峡库区消落带水位变化具有很好的适应能力，能够对水位变化做出积极的响应，平衡各元素的积累量，维持植株正常生长。 Abstract:The construction of the Three Gorges Dam reservoir spans the Yangtze River, China, forming a hydro-fluctuation belt with a water level drop of nearly 30 m and an area of 300 km2. The unique anthropogenic hydrological regime of the Three Gorges Dam has had significant negative impacts on the reservoir's riparian ecosystem. Some flooding-intolerant plants living within the belt gradually died off, which exacerbated vegetation habitat fragmentation and deleteriously affected the biological diversity, ecosystem structures, and functions of the water-fluctuation zone. Therefore, a pressing scientific challenge is to recover and restore the vegetation there and ensure proper ecological function. Previous studies have shown that Taxodium distichum is a flooding-tolerant plant and has been used for vegetation reconstruction. The nutritional characteristics of plants in a particular area can reflect the eco-physiological processes of plants, and can serve as crucial indicators of the structure and function of the local ecosystem. The nutritional characteristics play a key role in adaptation to anti-seasonal flooding, and might reveal clues about the adaptation mechanisms of plants in the hydro-fluctuation belt of the Three Gorges reservoir area. To contribute to this understanding, the nutritional characteristics of T. distichum growing in the reservoir riparian region of Zhongxian county, which had been planted in 2012, were studied. Element contents of three sample zones in low water elevation (165 m)-SD, high water elevation (170 m)-SL, and the control-CK(175 m) were determined in 2015. The macroelement, secondary element, and micronutrient contents in root and leaves of plants were measured. The results showed that:(1) Concentrations of N, P, K, Ca, and Zn in leaves and roots of T. distichum under flooding significantly decreased compared to CK, whereas Fe and Mn contents significantly increased. (2) Some nutrient concentrations of T. distichum under flooding decreased, but still maintained their normal performance. (3) Correlation analysis showed that plant heights were positively correlated with the concentrations of N, P, K, and Mg; plant heights were negatively correlated with the concentrations of Fe, Cu, and Mn; canopies of plants were positively correlated with the concentrations of N, P, K, and Mg, but negatively correlated with Fe and Mn. This investigation indicates that water level change had significantly influenced the nutritional characteristics of T. distichum in water-level-fluctuating zone of the Three Gorges Reservoir. T. distichum had good adaptability to the changed water habitat. 参考文献 相似文献 引证文献

Nonlinear optics in the mid-infrared: new morning

Recent breakthroughs in ultrafast photonics in the mid-IR help understand complex interactions of high-intensity mid-IR field waveforms with matter, offer new approaches for x-ray generation, enable mid-IR laser filamentation in the atmosphere, facilitate lasing in filaments, give rise to unique regimes of laser-matter interactions, and reveal unexpected properties of materials in the mid-IR range.

Thrust Calculation for Low-Reynolds-Number Micronozzles

Micronozzles represent a unique flow regime defined by low Reynolds numbers () and supersonic Mach numbers. Currently, the classic method of calculating thrust is used by the micropropulsion community to determine nozzle performance from simulation data. This approach accounts for momentum flux and pressure imbalance at the nozzle exit, and it assumes that the viscous stress tensor’s contribution to thrust is negligible. This assumption, however, can break down at low Reynolds numbers, where viscous forces play a significant role in the flow dynamics. In this paper, an extended method of calculating thrust, which accounts for the force due to the viscous stress tensor, is derived from the Navier–Stokes equation. Computational fluid dynamic simulations are then used to assess and quantify the error produced by the classic method at low Reynolds numbers (). Two micronozzle geometries are used as test cases: 1) an truncated planar plug nozzle, and 2) a 30 deg linear-walled planar de Laval nozzle. Results indicate that the accuracy of the classic method begins to break down at , below which there is a significant risk that the classic method will produce erroneous results. Moreover, for , the classic method has the potential to misrepresent the thrust of a simulated micronozzle by 50%.

UNVEILING THE ROLE OF GALACTIC ROTATION ON STAR FORMATION

ABSTRACT We study the star formation process at galactic scales and the role of rotation through numerical simulations of spiral and starburst galaxies using the adaptive mesh refinement code Enzo. We focus on the study of three integrated star formation laws found in the literature: the Kennicutt–Schmidt (KS) and Silk–Elmegreen (SE) laws, and the dimensionally homogeneous equation proposed by Escala . We show that using the last we take into account the effects of the integration along the line of sight and find a unique regime of star formation for both types of galaxies, suppressing the observed bi-modality of the KS law. We find that the efficiencies displayed by our simulations are anti-correlated with the angular velocity of the disk Ω for the three laws studied in this work. Finally, we show that the dimensionless efficiency of star formation is well represented by an exponentially decreasing function of , where is the initial free-fall time. This leads to a unique galactic star formation relation which reduces the scatter of the bi-modal KS, SE, and Escala relations by 43%, 43%, and 35%, respectively.

The ABACC experience: continuity and credibility in the nuclear programs of Brazil and Argentina

ABSTRACTThe Brazilian-Argentine Agency for Accounting and Control of Nuclear Materials (ABACC) is a unique bilateral nonproliferation regime created by Brazil and Argentina after a long process of negotiations and confidence building. The creation of the agency in July 1991 marked a paradigmatic shift in the Brazilian-Argentine relationship, converting their long rivalry into a profound strategic partnership. This article presents a historical overview of the creation of ABACC and discusses how it paved the way for the integration of Brazil and Argentina into the nonproliferation regime. The article also shows how ABACC tackled nonproliferation challenges in the twenty-first century, helping Brazil and Argentina continue their nuclear programs with fewer risks to the autonomy and development goals traditionally defended in their foreign policies.

Theory of driven nonequilibrium critical phenomena

A system driven in the vicinity of its critical point by varying a relevant field in an arbitrary function of time is a generic system that possesses a long relaxation time compared with the driving time scale and thus represents a large class of nonequilibrium systems. For such a manifestly nonlinear nonequilibrium strongly fluctuating system, we show that there exists universal nonequilibrium critical behavior that is well described incredibly by its equilibrium critical properties. A dynamic renormalization-group theory is developed to account for the behavior. The weak driving may give rise to several time scales depending on its form and thus rich nonequilibrium phenomena of various regimes and their crossovers, negative susceptibilities, as well as violation of fluctuation-dissipation theorem. An initial condition that can be in either equilibrium or nonequilibrium but has longer correlations than the driving scales also results in a unique regime and complicates the situation. Implication of the results on measurement is also discussed. The theory may shed light on study of other nonequilibrium systems and even nonlinear science.

Interplay between evanescence and disorder in deep subwavelength photonic structures.

Deep subwavelength features are expected to have minimal impact on wave transport. Here we show that in contrast to this common understanding, disorder can have a dramatic effect in a one-dimensional disordered optical system with spatial features a thousand times smaller than the wavelength. We examine a unique regime of Anderson localization where the localization length is shown to scale linearly with the wavelength instead of diverging, because of the role of evanescent waves. In addition, we demonstrate an unusual order of magnitude enhancement of transmission induced due to localization. These results are described for electromagnetic waves, but are directly relevant to other wave systems such as electrons in multi-quantum-well structures.

Reconsidering China’s South China Sea Claims: Compromising an Operationally Closed System of the Law of the Sea?

The uniqueness of China’s approach in the China–Philippine arbitration is demonstrated in its explication of the dash-line claim. A trend of territorialization in the dash-line claim is discernible since China deems the dash line to be one means for delineating maritime limits and for drawing a maritime boundary, namely maritime delimitation. This position and its connotation not only worry the Philippines but also all stakeholder countries. One explanation is China’s reading of the relations between the law of sea and public international law, which implies that the law of the sea has been established as a unique legal regime and, thus, can be operated in an exclusive manner. This approach, which has also been dubbed ‘the-land-prioritizes-the-sea’ approach runs the risk of isolating the law of the sea regime from the terrain of general international law. The key lies in treating the law of the sea as a regime characterized with conditioned operational closure, so that the spirit of ‘land-dominates-the-sea’ can be meaningfully honoured and implemented.

Magnetic activity of interacting binaries

AbstractInteracting binaries provide unique parameter regimes, both rapid rotation and tidal distortion, in which to test stellar dynamo theories and study the resulting magnetic activity. Close binaries such as cataclysmic variables (CVs) have been found to differentially rotate, and so can provide testbeds for tidal dissipation efficiency in stellar convective envelopes, with implications for both CV and planet-star evolution. Furthermore, CVs show evidence of preferential emergence of magnetic flux tubes towards the companion star, as well as large, long-lived prominences that form preferentially within the binary geometry. Moreover, RS CVn binaries also show clear magnetic interactions between the two components in the form of coronal X-ray emission. Here, we review several examples of magnetic interactions in different types of close binaries.

Characteristics of Nanosecond Pulsed Discharges in Atmospheric Helium Microplasmas**supported by the Natural Sciences and Engineering Research Council of Canada (NSERC) — Discovery Grant (No. 342369)

Microplasmas are very interesting due to their unique properties and achievable regimes maintained at atmospheric pressures. Due to the small scales, numerical modeling could contribute to the understanding of underlying phenomena as it provides access to local parameters—and complements experimental global characteristics. A self-consistent formalism, applied to nanosecond pulsed atmospheric non-equilibrium helium plasmas, reveals that several successive discharges can persist as a result of a combined volume and dielectric surface effects. The valuable insights provided by the spatiotemporal simulation results show the critical importance of coupled gas and plasma dynamics—namely gas heating and electric field reversals.

He Paid, She Paid: Exploiting Israeli Courts' Rulings on Litigation Costs to Explore Gender Biases

This study documents gender disparities in litigation‐cost rulings in Israel. It expands on the existing literature on judicial bias in at least two important ways: by controlling for the merits of the cases and by focusing on civil litigation. The first improvement is methodological. The unique Israeli regime of litigation costs allows us to control for the merit of the cases, as well as for other typically unobservable variables, and thus to isolate and observe judicial bias. The second improvement on the existing literature on judicial bias involves focusing on outcome disparities in the civil (rather than criminal) justice system. Although numerous studies explore gender‐based disparities in the criminal justice sphere, only a very small number of studies explore such disparities in the civil arena. We found clear disparities in the allocation of litigation costs between men and women. Male plaintiffs who lost were ordered to pay the winners' legal fees more often than were losing women as sole plaintiffs or as part of all‐women plaintiff groups. Likewise, the fees women plaintiffs who lost a case were obliged to pay were less than those required of losing men, and women defendants who won cases received higher fee awards than similarly situated men.