String fragmentation with a time-dependent tension

AbstractMotivated by recent theoretical arguments that expanding strings can be regarded as having a temperature that is inversely proportional to the proper time, $$\tau $$ τ , we investigate the consequences of adding a term $$\propto 1/\tau $$ ∝ 1 / τ to the string tension in the Lund string-hadronization model. The lattice value for the tension, $$\kappa _0 \sim 0.18\,{\mathrm {GeV}}^2\sim 0.9\,{\mathrm {GeV}}/{\mathrm {fm}}$$ κ 0 ∼ 0.18 GeV 2 ∼ 0.9 GeV / fm , is then interpreted as the late-time/equilibrium limit. A generic prediction of this type of model is that early string breaks should be associated with higher strangeness (and baryon) fractions and higher fragmentation $$\langle p_\perp \rangle $$ ⟨ p ⊥ ⟩ values. It should be possible to use archival ee data sets to provide model-independent constraints on this type of scenario, and we propose a few simple key measurements to do so.

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DARK ENERGY, WITH SIGNATURES

International Journal of Modern Physics D ◽

10.1142/s0218271810018372 ◽

2010 ◽

Vol 19 (14) ◽

pp. 2325-2330

Author(s):

SOURISH DUTTA ◽

ROBERT J. SCHERRER ◽

STEPHEN D. H. HSU

Keyword(s):

Dark Energy ◽

Equation Of State ◽

Energy Scale ◽

Fine Tuning ◽

Time Dependent ◽

Late Time ◽

Particle Content ◽

Energy Field ◽

Energy Models ◽

New Energy

We propose a class of simple dark energy models which predict a late-time dark radiation component and a distinctive time-dependent equation of state w(z) for redshift z < 3. The dark energy field can be coupled strongly enough to standard model particles to be detected in colliders, and the model requires only modest additional particle content and little or no fine-tuning other than a new energy scale of order milli-electron volts.

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Averaging generalized scalar field cosmologies II: locally rotationally symmetric Bianchi I and flat Friedmann–Lemaître–Robertson–Walker models

The European Physical Journal C ◽

10.1140/epjc/s10052-021-09230-5 ◽

2021 ◽

Vol 81 (6) ◽

Author(s):

Genly Leon ◽

Sebastián Cuéllar ◽

Esteban González ◽

Samuel Lepe ◽

Claudio Michea ◽

...

Keyword(s):

Scalar Field ◽

Nonlinear Dynamical Systems ◽

Perturbation Parameter ◽

Time Dependent ◽

Late Time ◽

De Sitter ◽

Time Dynamics ◽

Locally Rotationally Symmetric ◽

Bianchi I ◽

Rotationally Symmetric

AbstractScalar field cosmologies with a generalized harmonic potential and a matter fluid with a barotropic equation of state (EoS) with barotropic index $$\gamma $$ γ for the locally rotationally symmetric (LRS) Bianchi I and flat Friedmann–Lemaître–Robertson–Walker (FLRW) metrics are investigated. Methods from the theory of averaging of nonlinear dynamical systems are used to prove that time-dependent systems and their corresponding time-averaged versions have the same late-time dynamics. Therefore, the simplest time-averaged system determines the future asymptotic behavior. Depending on the values of $$\gamma $$ γ , the late-time attractors of physical interests are flat quintessence dominated FLRW universe and Einstein-de Sitter solution. With this approach, the oscillations entering the system through the Klein–Gordon (KG) equation can be controlled and smoothed out as the Hubble parameter H – acting as time-dependent perturbation parameter – tends monotonically to zero. Numerical simulations are presented as evidence of such behavior.

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The Effect of Anticipatory Repudiation: Principle and Policy

The Cambridge Law Journal ◽

10.1017/s0008197300010552 ◽

1962 ◽

Vol 20 (2) ◽

pp. 213-233 ◽

Cited By ~ 1

Author(s):

P. M. Nienaber

Keyword(s):

Proper Time ◽

Common Knowledge ◽

The Other ◽

Entire Period ◽

Sales Manager ◽

Local Authorities ◽

Contract Price ◽

House Of Lords ◽

Pertinent Question ◽

Do So

IThe facts of the recent House of Lords decision, White and Carter (Councils), Ltd. v. McGregor, were so simple and have been canvassed so thoroughly as to be now practically a matter of common knowledge. The appellants' business consisted in the placing of advertisements, for a fee, on litter bins which were then distributed to various local authorities. They agreed to run the respondents' advertisement for a period of three years. The respondents repudiated on the ground that their sales manager who had concluded the contract had no authority to do so. The appellants refused to accept the repudiation and duly displayed the advertisements for the entire period, bringing at the proper time a suit for the full amount owing under the contract. The pertinent question was: were the appellants entitled to dismiss the repudiation and give effect to the contract on their side in order to secure performance on the other side; or rather were they obliged to adopt the repudiation as the end of the contract and the beginning of a suit for damages subject to mitigation? The latter view prevailed in all but the House of Lords where a majority of three to two preferred the former.In coming to this conclusion the House of Lords in effect overruled an earlier decision, viz., Langford and Co., Ltd. v. Dutch, the facts of which were virtually on all fours with those of the present case. In Langford's case the appellant was unsuccessful in recovering the contract price for exhibiting an advertisement film which he persisted in showing despite the respondent's repudiation of the contract.

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Simulation and prediction of dengue outbreaks based on an SIR model with a time-dependent transmission rate including meteorological data. An example for Colombo and Jakarta

International Journal of Biomathematics ◽

10.1142/s179352452150073x ◽

2021 ◽

pp. 2150073

Author(s):

Peter Heidrich ◽

Thomas Götz

Keyword(s):

Transmission Rate ◽

Meteorological Data ◽

Weather Conditions ◽

Time Dependent ◽

Data Sets ◽

Vector Borne Diseases ◽

Dengue Outbreaks ◽

Vector Borne ◽

Text Model ◽

Periodic Transmission

Vector-borne diseases can usually be examined with a vector–host model like the [Formula: see text] model. This, however, depends on parameters that contain detailed information about the mosquito population that we usually do not know. For this reason, in this article, we reduce the [Formula: see text] model to an [Formula: see text] model with a time-dependent and periodic transmission rate [Formula: see text]. Since the living conditions of the mosquitos depend on the local weather conditions, meteorological data sets flow into the model in order to achieve a more realistic behavior. The developed [Formula: see text] model is adapted to existing data sets of hospitalized dengue cases in Jakarta (Indonesia) and Colombo (Sri Lanka) using numerical optimization based on Pontryagin’s maximum principle. A previous data analysis shows that the results of this parameter fit are within a realistic range and thus allow further investigations. Based on this, various simulations are carried out and the prediction quality of the model is examined.

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Large-Scale Estimates of LGBQ-Heterosexual Disparities in the Presence of Potentially Mischievous Responders: A Preregistered Replication and Comparison of Methods

AERA Open ◽

10.1177/2332858419888892 ◽

2019 ◽

Vol 5 (4) ◽

pp. 233285841988889 ◽

Cited By ~ 1

Author(s):

Joseph R. Cimpian ◽

Jennifer D. Timmer

Keyword(s):

Large Scale ◽

Minority Groups ◽

Survey Development ◽

Data Sets ◽

The Past ◽

Development Methodology ◽

Data Validity ◽

Regression Adjustment ◽

Better Than ◽

Do So

Although numerous survey-based studies have found that students who identify as lesbian, gay, bisexual, or questioning (LGBQ) have elevated risk for many negative academic, disciplinary, psychological, and health outcomes, the validity of the types of data on which these results rest have come under increased scrutiny. Over the past several years, a variety of data-validity screening techniques have been used in attempts to scrub data sets of “mischievous responders,” youth who systematically provide extreme and untrue responses to outcome items and who tend to falsely report being LGBQ. We conducted a preregistered replication of Cimpian et al. with the 2017 Youth Risk Behavior Survey to (1) estimate new LGBQ-heterosexual disparities on 20 outcomes; (2) test a broader, mechanistic theory relating mischievousness effects with a feature of items (i.e., item response-option extremity); and (3) compare four techniques used to address mischievous responders. Our results are consistent with Cimpian et al.’s findings that potentially mischievous responders inflate LGBQ-heterosexual disparities, do so more among boys than girls, and affect outcomes differentially. For example, we find that removing students suspected of being mischievous responders can cut male LGBQ-heterosexual disparities in half overall and can completely or mostly eliminate disparities in outcomes including fighting at school, driving drunk, and using cocaine, heroin, and ecstasy. Methodologically, we find that some methods are better than others at addressing the issue of data integrity, with boosted regressions coupled with data removal leading to potentially very large decreases in the estimates of LGBQ-heterosexual disparities, but regression adjustment having almost no effect. While the empirical focus of this article is on LGBQ youth, the issues discussed are relevant to research on other minority groups and youth generally, and speak to survey development, methodology, and the robustness and transparency of research.

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De-noising of transient electromagnetic data based on the long short-term memory-autoencoder

Geophysical Journal International ◽

10.1093/gji/ggaa424 ◽

2020 ◽

Vol 224 (1) ◽

pp. 669-681

Author(s):

Sihong Wu ◽

Qinghua Huang ◽

Li Zhao

Keyword(s):

Field Data ◽

Short Term Memory ◽

Noise Removal ◽

Data Sets ◽

Late Time ◽

Short Term ◽

Term Memory ◽

Transient Electromagnetic ◽

Long Short Term Memory

SUMMARY Late-time transient electromagnetic (TEM) data contain deep subsurface information and are important for resolving deeper electrical structures. However, due to their relatively small signal amplitudes, TEM responses later in time are often dominated by ambient noises. Therefore, noise removal is critical to the application of TEM data in imaging electrical structures at depth. De-noising techniques for TEM data have been developed rapidly in recent years. Although strong efforts have been made to improving the quality of the TEM responses, it is still a challenge to effectively extract the signals due to unpredictable and irregular noises. In this study, we develop a new type of neural network architecture by combining the long short-term memory (LSTM) network with the autoencoder structure to suppress noise in TEM signals. The resulting LSTM-autoencoders yield excellent performance on synthetic data sets including horizontal components of the electric field and vertical component of the magnetic field generated by different sources such as dipole, loop and grounded line sources. The relative errors between the de-noised data sets and the corresponding noise-free transients are below 1% for most of the sampling points. Notable improvement in the resistivity structure inversion result is achieved using the TEM data de-noised by the LSTM-autoencoder in comparison with several widely-used neural networks, especially for later-arriving signals that are important for constraining deeper structures. We demonstrate the effectiveness and general applicability of the LSTM-autoencoder by de-noising experiments using synthetic 1-D and 3-D TEM signals as well as field data sets. The field data from a fixed loop survey using multiple receivers are greatly improved after de-noising by the LSTM-autoencoder, resulting in more consistent inversion models with significantly increased exploration depth. The LSTM-autoencoder is capable of enhancing the quality of the TEM signals at later times, which enables us to better resolve deeper electrical structures.

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On the Characterization and Forecasting of Ground Displacements of Ocean-Reclaimed Lands

Remote Sensing ◽

10.3390/rs12182971 ◽

2020 ◽

Vol 12 (18) ◽

pp. 2971

Author(s):

Jingzhao Ding ◽

Qing Zhao ◽

Maochuan Tang ◽

Fabiana Calò ◽

Virginia Zamparelli ◽

...

Keyword(s):

Time Series ◽

Ground Deformation ◽

Proper Time ◽

Global Climate ◽

Time Dependent ◽

Ground Displacement ◽

Data Set ◽

Future Evolution ◽

Adopted Model ◽

Sar Data

In this work, we study ground deformation of ocean-reclaimed platforms as retrieved from interferometric synthetic aperture radar (InSAR) analyses. We investigate, in particular, the suitability and accuracy of some time-dependent models used to characterize and foresee the present and future evolution of ground deformation of the coastal lands. Previous investigations, carried out by the authors of this paper and other scholars, related to the zone of the ocean-reclaimed lands of Shanghai, have already shown that ocean-reclaimed lands are subject to subside (i.e., the ground is subject to settling down due to soil consolidation and compression), and the temporal evolution of that deformation follows a certain predictable model. Specifically, two time-gapped SAR datasets composed of the images collected by the ENVISAT ASAR (ENV) from 2007 to 2010 and the COSMO-SkyMed (CSK) sensors, available from 2013 to 2016, were used to generate long-term ground displacement time-series using a proper time-dependent geotechnical model. In this work, we use a third SAR data set consisting of Radarsat-2 (RST-2) acquisitions collected from 2012 to 2016 to further corroborate the validity of that model. As a result, we verified with the new RST-2 data, partially covering the gap between the ENV and CSK acquisitions, that the adopted model fits the data and that the model is suitable to perform future projections. Furthermore, we extended these analyses to the area of Pearl River Delta (PRD) and the city of Shenzhen, China. Our study aims to investigate the suitability of different time-dependent ground deformation models relying on the different geophysical conditions in the two areas of Shanghai and Shenzhen, China. To this aim, three sets of SAR data, collected by the ENV platform (from both ascending and descending orbits) and the Sentinel-1A (S1A) sensor (on ascending orbits), were used to obtain the ground displacement time-series of the Shenzhen city and its surrounding region. Multi-orbit InSAR data products were also combined to discriminate the up–down (subsidence) ground deformation time-series of the coherent points, which are then used to estimate the parameters of the models adopted to foresee the future evolution of the land-reclaimed ground consolidation procedure. The exploitation of the obtained geospatial data and products are helpful for the continuous monitoring of coastal environments and the evaluation of the socio-economical impacts of human activities and global climate change.

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Radiocarbon and Protein Analyses Indicate an Early Holocene Age for the Osseous Rod from Grenfell, Saskatchewan, Canada

American Antiquity ◽

10.7183/0002-7316.79.4.782 ◽

2014 ◽

Vol 79 (4) ◽

pp. 782-793 ◽

Cited By ~ 6

Author(s):

John W. Ives ◽

Duane Froese ◽

Matthew Collins ◽

Fiona Brock

Keyword(s):

Mass Spectrometry ◽

North America ◽

Accelerator Mass Spectrometry ◽

Early Holocene ◽

Raw Material ◽

Long Bone ◽

Data Sets ◽

Additional Information ◽

Made In ◽

Do So

AbstractThe Grenfell bone rod resembles other instances of Clovis-era organic or osseous technology and has on a number of occasions been considered with other Clovis bone, antler, and ivory rods or beveled artifacts. It had been suspected of being constructed from proboscidean long bone. As an early discovery (made in 1883), the Grenfell artifact had somewhat obscure provenience details and a lengthy curatorial history. We describe accelerator mass spectrometry and zooarchaeology by mass spectrometry methods that allow rapid, minimally destructive determinations of both the age and the raw material composition of osseous artifacts. Our analysis reveals that the Grenfell artifact is actually a terminal Paleoindian-era manifestation made of bison bone. Similar methods could be more widely applied in North America in order to build more refined data sets for osseous technologies. These results also reveal the ease with which archaeologists can secure additional information from existing collections, highlighting our ethical obligations to do so.

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