Temporal Boundary Research Articles

Direct determinations of the nucleon and pionσterms at nearly physical quark masses

We present a high statistics study of the pion and nucleon light and strange quark sigma terms using ${N}_{f}=2$ dynamical nonperturbatively improved clover fermions with a range of pion masses down to ${m}_{\ensuremath{\pi}}\ensuremath{\sim}150\text{ }\text{ }\mathrm{MeV}$ and several volumes, $L{m}_{\ensuremath{\pi}}=3.4$ up to 6.7, and lattice spacings, $a=0.06--0.08\text{ }\text{ }\mathrm{fm}$, enabling a study of finite volume and discretization effects for ${m}_{\ensuremath{\pi}}\ensuremath{\gtrsim}260\text{ }\text{ }\mathrm{MeV}$. Systematics are found to be reasonably under control. For the nucleon we obtain ${\ensuremath{\sigma}}_{\ensuremath{\pi}N}=35(6)\text{ }\text{ }\text{MeV}$ and ${\ensuremath{\sigma}}_{s}=35(12)\text{ }\text{ }\mathrm{MeV}$, or equivalently in terms of the quark fractions, ${f}_{{T}_{u}}=0.021(4)$, ${f}_{{T}_{d}}=0.016(4)$ and ${f}_{{T}_{s}}=0.037(13)$, where the errors include estimates of both the systematic and statistical uncertainties. These values, together with perturbative matching in the heavy quark limit, lead to ${f}_{{T}_{c}}=0.075(4)$, ${f}_{{T}_{b}}=0.072(2)$ and ${f}_{{T}_{t}}=0.070(1)$. In addition, through the use of the (inverse) Feynman-Hellmann theorem our results for ${\ensuremath{\sigma}}_{\ensuremath{\pi}N}$ are shown to be consistent with the nucleon masses determined in the analysis. For the pion we implement a method which greatly reduces excited state contamination to the scalar matrix elements from states traveling across the temporal boundary. This enables us to demonstrate the Gell-Mann-Oakes-Renner expectation ${\ensuremath{\sigma}}_{\ensuremath{\pi}}={m}_{\ensuremath{\pi}}/2$ over our range of pion masses.

Direct numerical simulation of the incompressible temporally developing turbulent boundary layer

We perform a direct numerical simulation (DNS) investigation of the incompressible temporally developing turbulent boundary layer. The approach is inspired by temporal simulations of flows which are generally thought of as developing in space, such as wakes and mixing layers. Compressible boundary layers have previously been studied in this manner yet the temporal approach appears to be under-exploited in the literature concerning incompressible boundary layers. The flow is the turbulent counterpart to the laminar Rayleigh problem or Stokes’ first problem, in which a fluid at rest is set into motion by a wall moving at constant velocity. An initial profile that models the effect of a wall-mounted trip wire is implemented and allows the characterisation of initial conditions by a trip Reynolds number. For the current set-up, a trip Reynolds number of 500 based on the trip-wire diameter successfully triggers transition yet only mildly perturbs the flow so it assumes a natural development at the lowest possible Reynolds number based on momentum thickness. A systematic trip study reveals that as the ratio of momentum thickness to trip-wire diameter approaches unity, our flow approaches a state free from the effects of its starting trip Reynolds number. The transport of a passive scalar by this flow is also simulated. The role played by domain size is investigated with two boxes, sized to accommodate two chosen final Reynolds numbers. Comparisons of the skin friction coefficient, velocity and scalar statistics demonstrate that the temporally developing boundary layer is a good model for the spatially developing boundary layer once initial conditions can be neglected. Analysis of similarity solutions suggests such a rapprochement of the spatial and temporal boundary layers may be expected at high Reynolds numbers given that the only terms that asymptotically persist are those common to both cases. If one seeks statistics for the turbulent boundary layer, the temporal boundary layer is therefore a viable method if modest convergence is sufficient. We suggest that such a temporal set-up could prove useful in the study of turbulence dynamics.

Dyons near the transition temperature in lattice QCD

We study the topological structure of QCD by cluster analysis. The fermionic topological charge density is constructed from low lying modes of overlap Dirac operator for three types of temporal boundary conditions for fermion field. This gives the possibility to mark all three dyon constitutents of KvBLL caloron in gluonic fields. The gluonic topological charge density is appearing in the process of overimproved gradient flow process stopped at the moment when it maximally matches the fermionic topological charge density. This corresponds to the smearing of gluonic fields up to the scale set by dyon size. The time-like Abelian monopoles and specific KvBLL pattern of Polyakov line correlate with topological clusters.

Large volumes and spectroscopy of walking theories

A detailed investigation of finite size effects is performed for SU(2) gauge theory with two fermions in the adjoint representation, which previous lattice studies have shown to be inside the conformal window. The system is investigated with different spatial and temporal boundary conditions on lattices of various spatial and temporal extensions, for two values of the bare fermion mass representing a {\em heavy} and {\em light} fermion regime. Our study shows that the infinite volume limit of masses and decay constants in the mesonic sector is reached only when the mass of the pseudoscalar particle $M_\mathrm{PS}$ and the spatial lattice size $L$ satisfy the relation $L M_\mathrm{PS} \ge 15$. This bound, which is at least a factor of three higher than what observed in QCD, is a likely consequence of the different spectral signatures of the two theories, with the scalar isosinglet ($0^{++}$ glueball) being the lightest particle in our model. In addition to stressing the importance of simulating large lattice sizes, our analysis emphasises the need to understand quantitatively the {\em full} spectrum of the theory rather than just the spectrum in the mesonic isotriplet sector. While for the lightest fermion measuring masses from gluonic operators proves to be still challenging, reliable results for glueball states are obtained at the largest fermion mass and, in the mesonic sector, for both fermion masses. As a byproduct of our investigation, we perform a finite size scaling of the pseudoscalar mass and decay constant. The data presented in this work support the conformal behaviour of this theory with an anomalous dimension $\gamma_* \simeq 0.37$.

Venus: Scalable Real-Time Spatial Queries on Microblogs with Adaptive Load Shedding

Microblogging services have become among the most popular services on the web in the last few years. This led to significant increase in data size, speed, and applications. This paper presents Venus ; a system that supports real-time spatial queries on microblogs. Venus supports its queries on a spatial boundary $R$ and a temporal boundary $T$ , from which only the top- $k$ microblogs are returned in the query answer based on a spatio-temporal ranking function. Supporting such queries requires Venus to digest hundreds of millions of real-time microblogs in main-memory with high rates, yet, it provides low query responses and efficient memory utilization. To this end, Venus employs: (1) an efficient in-memory spatio-temporal index that digests high rates of incoming microblogs in real time, (2) a scalable query processor that prune the search space, $R$ and $T$ , effectively to provide low query latency on millions of items in real time, and (3) a group of memory optimization techniques that provide system administrators with different options to save significant memory resources while keeping the query accuracy almost perfect. Venus memory optimization techniques make use of the local arrival rates of microblogs to smartly shed microblogs that are old enough not to contribute to any query answer. In addition, Venus can adaptively, in real time, adjust its load shedding based on both the spatial distribution and the parameters of incoming query loads. All Venus components can accommodate different spatial and temporal ranking functions that are able to capture the importance of each dimension differently depending on the applications requirements. Extensive experimental results based on real Twitter data and actual locations of Bing search queries show that Venus supports high arrival rates of up to 64 K microblogs/second and average query latency of 4 msec.

Analysis of interconnecting energy systems over a synchronized life cycle

Life cycle analysis (LCA) using the process chain analysis (PCA) approach has been widely applied to energy systems. When applied to an individual energy system, such as coal or nuclear electricity generation, an LCA–PCA methodology can yield relatively accurate results with its detailed process representation based on engineering data. However, there are fundamental issues when applying conventional LCA–PCA methodology to a more complex life cycle, namely, a synchronized life cycle of interconnected energy systems. A synchronized life cycle of interconnected energy systems is established through direct interconnections among the processes of different energy systems, and all interconnecting systems are bounded within the same timeframe. Under such a life cycle formation, there are some major complications when applying conventional LCA–PCA methodology to evaluate the interconnecting energy systems. Essentially, the conventional system and boundary formulations developed for a life cycle of individual energy system cannot be directly applied to a life cycle of interconnected energy systems. To address these inherent issues, a new LCA–PCA methodology is presented in this paper, in which a new concept of partial temporal boundary is introduced to synchronize the interconnecting energy systems. The importance and advantages of these new developments are demonstrated through a case study on the life cycle of the coal–uranium system.

Dual condensates at finite isospin chemical potential

The dual observables as order parameters for center symmetry are tested at finite isospin chemical potential μI in a Polyakov-loop enhanced chiral model of QCD with physical quark masses. As a counterpart of the dressed Polyakov-loop, the first Fourier moment of pion condensate is introduced for μI>mπ/2 under the temporal twisted boundary conditions for quarks. We demonstrate that this dual condensate exhibits the similar temperature dependence as the conventional Polyakov-loop. We confirm that its rapid increase with T is driven by the evaporating of pion condensation. On the other hand, the dressed Polyakov-loop shows abnormal thermal behavior, which even decreases with T at low temperatures due to the influence of pion condensate. We also find that the dressed Polyakov-loop always rises most steeply at the chiral transition temperature, which is consistent with the previous results in Nambu–Jona-Lasinio (NJL) model and its variants without considering the center symmetry. Since both quantities are strongly affected by the chiral symmetry and pion condensation, we conclude that it is difficult to clarify the deconfinement transition from the dual condensates in this situation within this model.

Greening the roadway: an assimilated planning approach and techniques based on spatiality

The special attribute of environmental parameters having no spatial or temporal boundary is what caters to the inter-relationship between various kinds and patterns of adjoining land uses. Understanding of the magnitude and directional flow of impact has given rise to an interlinked conceptual base to plan for a greener roadway in an Indian perspective. The inter-linkages as established in this study are between road runoff and liquid waste from adjacent settlements; vehicular emission of greenhouse gas, air pollutants and noise and exposure of road side dwellers to the same due to lack of adequate sink or abatement measures; huge amount of ground water extraction for road construction at a time and conflicts with local users, etc. These parallel moving issues have been addressed through simultaneous multi-approach (SMA) solution. It involves meticulous spatial arrangement of paved and unpaved surface within the right of way (RoW) and use of integrated management system for tapping road runoff and creating emission sink; utilisation of special material combination for reduction in air pollutants; innovative techniques and simultaneous approaches to manage liquid and solid waste generated in the vicinity; devise reparation activities to compensate for usage of natural resources, etc.

Zircon geochronology and geochemistry to constrain the youngest eruption events and magma evolution of the Mid-Miocene ignimbrite flare-up in the Pannonian Basin, eastern central Europe

A silicic ignimbrite flare-up episode occurred in the Pannonian Basin during the Miocene, coeval with the syn-extensional period in the region. It produced important correlation horizons in the regional stratigraphy; however, they lacked precise and accurate geochronology. Here, we used U–Pb (LA-ICP-MS and ID-TIMS) and (U–Th)/He dating of zircons to determine the eruption ages of the youngest stage of this volcanic activity and constrain the longevity of the magma storage in crustal reservoirs. Reliability of the U–Pb data is supported by (U–Th)/He zircon dating and magnetostratigraphic constraints. We distinguish four eruptive phases from 15.9 ± 0.3 to 14.1 ± 0.3 Ma, each of which possibly includes multiple eruptive events. Among these, at least two large volume eruptions (>10 km3) occurred at 14.8 ± 0.3 Ma (Demjen ignimbrite) and 14.1 ± 0.3 Ma (Harsany ignimbrite). The in situ U–Pb zircon dating shows wide age ranges (up to 700 kyr) in most of the crystal-poor pyroclastic units, containing few to no xenocrysts, which implies efficient recycling of antecrysts. We propose that long-lived silicic magma reservoirs, mostly kept as high-crystallinity mushes, have existed in the Pannonian Basin during the 16–14 Ma period. Small but significant differences in zircon, bulk rock and glass shard composition among units suggest the presence of spatially separated reservoirs, sometimes existing contemporaneously. Our results also better constrain the time frame of the main tectonic events that occurred in the Northern Pannonian Basin: We refined the upper temporal boundary (15 Ma) of the youngest counterclockwise block rotation and the beginning of a new deformation phase, which structurally characterized the onset of the youngest volcanic and sedimentary phase.

What is the Temporal Analog of Reflection and Refraction of Optical Beams?

It is shown numerically and analytically that when an optical pulse approaches a moving temporal boundary across which the refractive index changes, it undergoes a temporal equivalent of reflection and refraction of optical beams at a spatial boundary. The main difference is that the role of angles is played by changes in the frequency. The frequency dependence of the dispersion of the material in which the pulse is propagating plays a fundamental role in determining the frequency shifts experienced by the reflected and refracted pulses. Our analytic expressions for these frequency shifts allow us to find the condition under which an analog of total internal reflection may occur at the temporal boundary.

TemporalClassifier

Users issuing query on search engine, expect results to more relevant to query topic rather than just the textual match with text in query. Studies conducted by few researchers shows that user want the search engine to understand the implicit intent of query rather than looking the textual match in hypertext structure of document or web page. In this paper the authors will be addressing queries that have any temporal intent and help the web search engines to classify them in certain categories. These classes or categories will help search engine to understand and cater the need of query. The authors will consider temporal expression (e.g. 1943) in document and categories them on the basis of temporal boundary of that query. Their experiment classifies the query and tries to suggest further course of action for search engines. Results shows that classifying the query to these classes will help user to reach his/her seeking information faster.

Korean Speakers' Knowledge of the Semantics and Pragmatics of Viewpoint Aspect in English

Semantically, viewpoint aspect encodes boundedness, the specification (or lack thereof) of a temporal boundary. Perfective viewpoint is bounded and situations presented in the perfective have reached the temporal boundary, whereas imperfective viewpoint is unbounded and situations presented in the imperfective have not. This semantic difference is reflected through the imperfective paradox interaction: telic predicates in the imperfective, but not those in the perfective, lose their completion entailments. Pragmatically, viewpoint aspect serves different discourse functions; the imperfective provides background information and it suspends the plot, whereas the perfective provides foreground information and it moves the plot along. This study examines Korean speakers understanding of the aforementioned semantic and pragmatic properties of viewpoint aspect in English. Results showed successful acquisition of the pragmatics but delayed acquisition of the semantics. It is argued that this disparity is accounted for by transfer of partial completion construals of perfectives in Korean. It also addresses implications of the results in light of the Interface Vulnerability Hypothesis arguing for the vulnerability of the syntax-pragmatics interface as compared to the syntax-semantics interface.

Wind turbine radiated acoustic signals—Propagation in a temporally and spatial variable marine meteorological boundary layer

The temporal and spatial properties of an acoustic field radiated from a wind turbine operating in a marine meteorological boundary layer and a spatial temporal variable impedance boundary will be quantified using paraxial equation based numerical simulations. A sound speed field will be constructed using wind field measurements made with a 915 MHZ radar wind speed sensor and local temperature and humidity measurements obtained from a meteorological tower. Temporally variable impedance boundary conditions for a tidal marine marsh will be included in the simulations.

The Reciprocal Relationship between Counterproductive Work Behavior and Workplace Mistreatment: Its Temporal Dynamics and Boundary Conditions

This research examines how employees’ behaviors shape their work environments and vice-versa. We identify and quantify the reciprocal relationship between three forms of workplace mistreatment (i.e., abusive supervision, ostracism, discrimination) and employees’ counterproductive work behavior (CWB) in a twelve-wave longitudinal study with a cross-lagged panel design. We show that employees’ bad behaviors at work (e.g., sabotage, theft, abuse of coworkers) are both a cause and a consequence of experiencing mistreatment from colleagues and supervisors. We investigate the temporal aspects of this reciprocal relationship and find that CWB-to-mistreatment and mistreatment-to-CWB effects both occur over a one-week time-span. Moreover, this reciprocal relationship continued across the twelve weeks of the study, and its magnitude neither intensified nor diminished over this time period. The CWB-to-mistreatment effect was roughly twice as large as the mistreatment-to-CWB effect, demonstrating the powerful influence of individuals’ behaviors on their work environments. Employees’ Conscientiousness moderated the reciprocal relationship by decreasing the frequency of CWB committed in response to mistreatment experienced the previous week, and to a lesser degree, by decreasing the frequency with which colleagues and supervisors mistreated employees who engaged in CWB the previous week. Surprisingly, no moderating influences were observed for individual differences in Honesty-Humility and Agreeableness, nor for organizational differences in procedural justice and the enforcement of an ethics code.

Cumulative Overall Resource Efficiency Assessment (COREA) for comparing bio-based products with their fossil-derived counterparts

Bio-based products potentially decrease consumption of non-renewable fossil resources compared to their fossil-derived counterparts, but are more demanding for bio-productive land use. Although thermodynamics-based resource accounting methods are available for calculating overall resource efficiency from a life cycle perspective, their accounting for bio-productive land resources as an input during quantification of efficiencies is unclear. This paper aims to fill the gap in scientific literature about how to calculate a cumulative overall resource efficiency indicator by developing a framework, called Cumulative Overall Resource Efficiency Assessment (COREA). COREA (i) takes into account bio-productive land resources and (ii) addresses the non-renewable character of fossil resources. To account for bio-productive land resources, two methodological questions need to be addressed: (1) “how to define the system boundary of the solar energy input in the primary biomass production system?” and (2) “how to choose the temporal system boundary of this system?”. Resource efficiencies are calculated for three cases at crop level and two cases at bio-based product level. To account for the non-renewable character of fossil resources, we propose an accounting approach that includes the ancient solar energy consumption of fossil resources. This methodological choice is illustrated through comparing the resource efficiencies of the two bio-based products with their fossil-based counterparts. The results showed that the bio-based products only had a higher resource efficiency than their fossil-derived counterparts if fossil resources were considered as ancient consumers of solar energy.

The sensory timecourses associated with conscious visual item memory and source memory

Previous event-related potential (ERP) findings have suggested that during visual item and source memory, nonconscious and conscious sensory (occipital–temporal) activity onsets may be restricted to early (0–800ms) and late (800–1600ms) temporal epochs, respectively. In an ERP experiment, we tested this hypothesis by separately assessing whether the onset of conscious sensory activity was restricted to the late epoch during source (location) memory and item (shape) memory. We found that conscious sensory activity had a late (>800ms) onset during source memory and an early (<200ms) onset during item memory. In a follow-up fMRI experiment, conscious sensory activity was localized to BA17, BA18, and BA19. Of primary importance, the distinct source memory and item memory ERP onsets contradict the hypothesis that there is a fixed temporal boundary separating nonconscious and conscious processing during all forms of visual conscious retrieval.

The Nature of Total War: Grasping the Global Environmental Dimensions of World War II

AbstractThe past decade has seen a proliferation of studies examining the environmental dimensions of World War II. This article analyses this literature by engaging with relevant parallel historiographical streams on the war and on non‐military environmental history. It suggests that scholars working with a non‐European focus have been innovative in their use of global and transnational approaches. Studies of Axis‐occupied Europe, on the other hand, have uncovered the nuanced dynamics behind the fascist regimes' efforts to manipulate nature. This article outlines the potential contributions of bringing these bodies of literature in dialogue. Moreover, this article contends that the impact of the Second World War on socio‐environmental dimensions can only be fully appreciated through studies that transcend a traditional temporal boundary.

Dyon structures in the deconfinement phase of lattice gluodynamics: Topological clusters, holonomies, and Abelian monopoles

The topological structure of lattice gluodynamics is studied at intermediate resolution scale in the deconfining phase with the help of a cluster analysis. UV filtered topological charge densities are determined from a fixed number of low-lying eigenmodes of the overlap Dirac operator with three types of temporal boundary conditions applied to the valence quark fields. This method usually allows to find all three distinguished (anti)dyon constituents in the gauge field of Kraan-van Baal-Lee-Lu (anti)caloron solutions. The clustering of the three topological charge densities in Monte Carlo generated configurations is then used to mark the positions of anticipated (anti)dyons of the corresponding type. In order to support this interpretation, inside these clusters, we search also for time-like Abelian monopole currents (defined in the maximally Abelian gauge) as well as for local holonomies with at least two approximately degenerated eigenvalues. Our results support the view that light dyon-antidyon pairs - in contrast to the heavy (anti)caloron dyon constituents - contribute dominantly to thermal Yang-Mills fields in the deconfinement phase. This paper is dedicated to the memory of Pierre van Baal and Dmitri Igorevich Diakonov who have influenced our work very much.

The Glasgow consensus on the delineation between pesticide emission inventory and impact assessment for LCA

Abstract Purpose Pesticides are applied to agricultural fields to optimise crop yield and their global use is substantial. Their consideration in life cycle assessment (LCA) is affected by important inconsistencies between the emission inventory and impact assessment phases of LCA. A clear definition of the delineation between the product system model (life cycle inventory—LCI, technosphere) and the natural environment (life cycle impact assessment—LCIA, ecosphere) is missing and could be established via consensus building. Methods A workshop held in 2013 in Glasgow, UK, had the goal of establishing consensus and creating clear guidelines in the following topics: (1) boundary between emission inventory and impact characterisation model, (2) spatial dimensions and the time periods assumed for the application of substances to open agricultural fields or in greenhouses and (3) emissions to the natural environment and their potential impacts. More than 30 specialists in agrifood LCI, LCIA, risk assessment and ecotoxicology, representing industry, government and academia from 15 countries and four continents, met to discuss and reach consensus. The resulting guidelines target LCA practitioners, data (base) and characterisation method developers, and decision makers. Results and discussion The focus was on defining a clear interface between LCI and LCIA, capable of supporting any goal and scope requirements while avoiding double counting or exclusion of important emission flows/impacts. Consensus was reached accordingly on distinct sets of recommendations for LCI and LCIA, respectively, recommending, for example, that buffer zones should be considered as part of the crop production system and the change in yield be considered. While the spatial dimensions of the field were not fixed, the temporal boundary between dynamic LCI fate modelling and steady-state LCIA fate modelling needs to be defined. Conclusions and recommendations For pesticide application, the inventory should report pesticide identification, crop, mass applied per active ingredient, application method or formulation type, presence of buffer zones, location/country, application time before harvest and crop growth stage during application, adherence with Good Agricultural Practice, and whether the field is considered part of the technosphere or the ecosphere. Additionally, emission fractions to environmental media on-field and off-field should be reported. For LCIA, the directly concerned impact categories and a list of relevant fate and exposure processes were identified. Next steps were identified: (1) establishing default emission fractions to environmental media for integration into LCI databases and (2) interaction among impact model developers to extend current methods with new elements/processes mentioned in the recommendations.

Speech repetition as a window on the neurobiology of auditory–motor integration for speech: A voxel-based lesion symptom mapping study

For more than a century, speech repetition has been used as an assay for gauging the integrity of the auditory–motor pathway in aphasia, thought classically to involve a linkage between Wernicke's area and Broca's area via the arcuate fasciculus. During the last decade, evidence primarily from functional imaging in healthy individuals has refined this picture both computationally and anatomically, suggesting the existence of a cortical hub located at the parietal–temporal boundary (area Spt) that functions to integrate auditory and motor speech networks for both repetition and spontaneous speech production. While functional imaging research can pinpoint the regions activated in repetition/auditory–motor integration, lesion-based studies are needed to infer causal involvement. Previous lesion studies of repetition have yielded mixed results with respect to Spt's critical involvement in speech repetition. The present study used voxel-based lesion symptom mapping (VLSM) to investigate the neuroanatomy of repetition of both real words and non-words in a sample of 47 patients with focal left hemisphere brain damage. VLSMs identified a large voxel cluster spanning gray and white matter in the left temporal–parietal junction, including area Spt, where damage was significantly related to poor non-word repetition. Repetition of real words implicated a very similar dorsal network including area Spt. Cortical regions including Spt were implicated in repetition performance even when white matter damage was factored out. In addition, removing variance associated with speech perception abilities did not alter the overall lesion pattern for either task. Together with past functional imaging work, our results suggest that area Spt is integral in both word and non-word repetition, that its contribution is above and beyond that made by white matter pathways, and is not driven by perceptual processes alone. These findings are highly consistent with the claim that Spt is an area of sensory-motor translation in speech processing.