Miracle-dz/UniFAR-FTUs huggingface dataset:
The Impacts of Climate Change on Coastal Georgia Heritage Tourism Sites

abstract:Climate change is a global issue that will impact the preservation of historic heritage sites. However, much of the research on the impacts of climate change on historic heritage sites has focused on Europe and in the United States, studies have largely centered on National Park Service (NPS) sites. In the state of Georgia, a number of heritage tourism destinations central to the state's vibrant tourism economy occur in its coastal zone, a zone navigating the impacts of sea-level rise, flooding, coastal erosion, and hurricanes. Given the limited understanding of the impacts on heritage tourism sites specifically within the state of Georgia—which has yet to develop a statewide adaptation plan—this study seeks to understand the impacts of climate change on heritage tourism sites from the perspective of site managers and staff. This study takes a multi-methodological approach utilizing surveys and archival research to understand site-specific impacts, management protocols, and management and staff views on climate change. The study focused on six sites in Georgia falling under different ownership structures and found that managers and staff at all sites reported damage from hurricanes and flooding and were concerned about the impacts of climate change and the long-term survival of their site.
Electromigration effect of Ni electrodes on the resistive switching characteristics of NiO thin films

The effects of Ni and Ni0.83Pt0. 17 alloy electrodes on the resistance switching of the dc-sputtered polycrystalline NiO thin films were investigated. The initial off-state resistances of the films were similar to that of Pt∕NiO∕Pt film. However, after the first cycle of switching, the off-state resistance significantly decreased in the films with Ni in the electrode. It can be attributed to the migration of Ni from electrodes to the NiO films. The improvement in data dispersion of switching parameters is explained in terms of the decrease of the effective thickness of the films resulting from the migration of Ni.
Friction of Teflon Sliding on Teflon

The low coefficient of friction for Teflon sliding on Teflon, as observed previously by others, has been found in this study to hold only if low sliding speeds and newly prepared surfaces are used. At high sliding speed, the nature of the surface is irreversibly changed such that subsequent sliding at low speed reveals a two‐ to threefold increase in the friction coefficient. In addition to the effect of high speed sliding, there are reversible changes in the friction of Teflon on Teflon dependent in part on temperature. As the temperature of Teflon is increased from below room temperature, a sharp and pronounced increase in the coefficient of friction is observed in the vicinity of 20°C. The existence of a phase transition in Teflon at this temperature indicates a close correlation between the frictional and the structural properties of this material.
Liftoff characteristics of turbulent jet diffusion flames

A theoretical analysis of turbulent jet diffusion flames is developed in which the flame is regarded as an ensemble of laminar diffusion flamelets that are highly distorted. The flow inhomogeneities are considered to be sufficiently strong to produce local quenching events for flamelets as a consequence of excessive flame stretch. The condition for flamelet extinction is derived in terms of the instantaneous scalar dissipation rate, which is ascribed a log-normal distribution. Percolation theory for a random network of stoichiometri c sheets is used to predict quenching thresholds that define liftoff heights. Predictions are shown to be in reasonably satisfactory agreement with experimentally measured liftoff heights of methane jet diffusion flames, within experimental uncertainties. UEL issuing from a tube or duct into an oxidizing atmosphere forms a jet in which combustion may occur. The associated combustion process is the most classical example of a diffusion flame. At sufficiently high velocities of fuel flow (fundamentally, at sufficiently large Reynolds numbers) the entire diffusion flame is turbulent. The turbulent jet diffusion flame begins at the mouth of the duct for a range of values of the exit velocity. When a critical exit velocity is exceeded, the flame abruptly is detached from the duct and acquires a new configuration of stabilization in which combustion begins a number of duct diameters downstream. Flames in this state, stabilized in the mixing region, are termed lifted diffusion flames, and the critical exit velocity at which they appear is called the liftoff velocity. The liftoff height is the centerline distance from the duct exit to the plane of flame stabilization. A further increase in the exit velocity increases the liftoff height without significantly modifying the turbulent flame height (the centerline distance from the duct exit to the plane at which, on the average, combustion ceases). There is a second critical value of the exit velocity, called the blowoff velocity, beyond which the flame cannot be stabilized in the mixing region. The present study addresses questions of the structure of lifted turbulent diffusion flames at exit velocities between liftoff and blowoff values. Attention is focused especially on the calculation of liftoff heights. Liftoff characteristics for turbulent jet diffusion flames are of practical importance in connection with flame stabilization. Conditions for liftoff and blowoff must be known in developing rational designs of burners, e.g., in diffusion-flame combustors for power production or in flaring applications for the petroleum industry. They are also of interest in connection with extinguishment of certain fires that may occur in oil or gas rigs. The present work is directed toward developing an improved fundamental understanding of liftoff phenomena that may later prove useful for these applications.
Structure and ferroelectric properties of P(VDF-TrFE) copolymers

Abstract P(VDF-TrFE) copolymers with approximately 30 mol% of TrFE content exhibit above room temperature a ferroelectric transition of first order type with a large thermal hysteresis. We present recent investigations of the ferroelectric phase and of the phase transition using several techniques: second harmonic generation of light, high resolution X-ray diffraction, quasi-elastic neutron scattering, small angle X-ray scattering, Brillouin scattering, far infrared absorption and submillimeter dielectric spectroscopy. These results provide information on both the small crystallites and the amorphous inter-crystalline regions and show that temperature cycling throughout the Curie transition is able to modify the superstructure and to enhance the degree of crystallinity of the polymer. Accordingly, low frequency dielectric measurements, thermal expansion results and Brillouin spectroscopic investigations can be discussed in taking into account the composite structure of the semi-crystalline material.
Low-energy collective dynamics of charge stripes in the doped nickelateLa2−xSrxNiO4+δobserved with optical conductivity measurements

We have investigated charge dynamics in the static stripe ordered phase of ${\mathrm{La}}_{2\ensuremath{-}x}{\mathrm{Sr}}_{x}\mathrm{Ni}{\mathrm{O}}_{4+\ensuremath{\delta}}$ at lattice temperatures below the charge ordering transition, via optical conductivity measurements at low energies $(1\char21{}10\phantom{\rule{0.3em}{0ex}}\mathrm{meV})$. The thermally activated dynamic response of the charge stripes is found to be characteristic of a collective mode such as a pinned charge density wave. At incommensurate doping levels, the pinning energy is reduced, owing to the presence of real-space defects in the stripe order, and a pronounced increase in the oscillator strength is seen. The results provide compelling evidence for the existence of low-energy collective modes of the charge stripes.
The Search for Interstellar C60

The optical region of a number of reddened O-type stars has been examined on Keck I HIRES spectrograms (R = 45,000) for evidence of interstellar C60. No absorption features were detected near the laboratory C60 wavelengths 3857 and 3980 Å. An interstellar feature is present at 6220.8 Å, but it is unacceptably far from the laboratory gas-phase wavelength of 6217.5 Å. It is probably just another of the weak diffuse interstellar bands (DIBs), which are numerous in that spectral region. The most astronomically promising C60 feature was measured in the laboratory at 3284 Å in liquid or solid matrices. Its gas-phase wavelength can be inferred either from matrix shifts of C60 features at longer wavelengths or from high-temperature gas-phase measurements. On that evidence, the interstellar feature could fall anywhere between about 3244 and 3306 Å. Its width is uncertain but here is taken to be about 1 Å . No interstellar absorption fitting these specifications and as strong as 16 mÅ has been detected in the stars observed, including Cyg OB2/8A of E(B-V) = 1.60. It follows that in that particular line of sight and for the assumed FWHM of 1 Å , N(C60) < 4.5 × 1011 cm-2. However, some recent laboratory spectroscopy suggests that its width may be very much larger, in which case this limit would be invalid. At this upper limit, the corresponding number of carbon atoms contained in neutral C60 indicates that that molecule would be only a minor contributor to the total amount of C in that direction, and would be less than 1% of the amount that may be tied up in the DIBs. Stronger C60 bands are known in the laboratory at approximately 2110 and 2566 Å, but the upper limit on 3284 Å suggests that they will not be easy to detect without high resolution, high signal-to-noise ratio (S/N) satellite spectroscopy and better laboratory gas-phase wavelengths. An estimate of the column density of C, under the assumption that the 9577, 9632 Å bands are indeed due to C and that the laboratory f-value is correct, indicates that the C/C60 abundance in that line of sight is greater than 100.
Transcription Factor Dynamics in Cross-Regulation of Plant Hormone Signaling Pathways

Cross-regulation between hormone signaling pathways is indispensable for plant growth and development. However, the molecular mechanisms by which multiple hormones interact and co-ordinate activity need to be understood. Here, we generated a cross-regulation network explaining how hormone signals are integrated from multiple pathways in etiolated Arabidopsis (Arabidopsis thaliana) seedlings. To do so we comprehensively characterized transcription factor activity during plant hormone responses and reconstructed dynamic transcriptional regulatory models for six hormones; abscisic acid, brassinosteroid, ethylene, jasmonic acid, salicylic acid and strigolactone/karrikin. These models incorporated target data for hundreds of transcription factors and thousands of protein-protein interactions. Each hormone recruited different combinations of transcription factors, a subset of which were shared between hormones. Hub target genes existed within hormone transcriptional networks, exhibiting transcription factor activity themselves. In addition, a group of MITOGEN-ACTIVATED PROTEIN KINASES (MPKs) were identified as potential key points of cross-regulation between multiple hormones. Accordingly, the loss of function of one of these (MPK6) disrupted the global proteome, phosphoproteome and transcriptome during hormone responses. Lastly, we determined that all hormones drive substantial alternative splicing that has distinct effects on the transcriptome compared with differential gene expression, acting in early hormone responses. These results provide a comprehensive understanding of the common features of plant transcriptional regulatory pathways and how cross-regulation between hormones acts upon gene expression.
Deficits in neuronal architecture but not over-inhibition are main determinants of reduced neuronal network activity in a mouse model of overexpression of Dyrk1A

Abnormal dendritic arbors, dendritic spine “dysgenesis” and excitation inhibition imbalance are main traits assumed to underlie impaired cognition and behavioral adaptation in intellectual disability. However, how these modifications actually contribute to functional properties of neuronal networks, such as signal integration or storage capacity is unknown. Here, we used a mouse model overexpressing Dyrk1A (Dual-specificity tyrosine [Y]-regulated kinase), one of the most relevant Down syndrome (DS) candidate genes, to gather quantitative data regarding hippocampal neuronal deficits produced by the overexpression of Dyrk1A in mice (TgDyrk1A; TG). TG mice showed impaired hippocampal recognition memory, altered excitation-inhibition balance and deficits in hippocampal CA1 LTP. We also detected for the first time that deficits in dendritic arborization in TG CA1 pyramidal neurons are layer-specific, with a reduction in the width of the stratum radiatum, the postsynaptic target site of CA3 excitatory neurons, but not in the stratum lacunosum-moleculare, which receives temporo-ammonic projections. To interrogate about the functional impact of layer-specific TG dendritic deficits we developed tailored computational multicompartmental models. Computational modelling revealed that neuronal microarchitecture alterations in TG mice lead to deficits in storage capacity, altered the integration of inputs from entorhinal cortex and hippocampal CA3 region onto CA1 pyramidal cells, important for coding place and temporal context and on connectivity and activity dynamics, with impaired the ability to reach high γ oscillations. Contrary to what is assumed in the field, the reduced network activity in TG is mainly contributed by the deficits in neuronal architecture and to a lesser extent by over-inhibition. Finally, given that therapies aimed at improving cognition have also been tested for their capability to recover dendritic spine deficits and excitation-inhibition imbalance, we also tested the short- and long-term changes produced by exposure to environmental enrichment (EE). Exposure to EE normalized the excitation inhibition imbalance and LTP, and had beneficial effects on short-term recognition memory. Importantly, it produced massive but transient dendritic remodeling of hippocampal CA1, that led to recovery of high γ oscillations, the main readout of synchronization of CA1 neurons, in our simulations. However, those effects where not stable and were lost after EE discontinuation. We conclude that layer-specific neuromorphological disturbances produced by Dyrk1A overexpression impair coding place and temporal context. Our results also suggest that treatments targeting structural plasticity, such as EE, even though hold promise towards improved treatment of intellectual disabilities, only produce temporary recovery, due to transient dendritic remodeling.
Irony detection engages the Precuneus and Inferior Frontal Gyrus and relies on integration of contextual cues and inferential skills

It has been suggested that irony is one of the most challenging forms of communication, consequently, it can be a valuable indicator of communication abilities. An ironic statement transmits the opposite meaning of its literal counterpart. The cognitive processes that may support the interpretation of irony include the Theory of Mind (ToM), executive functions, and processing style. The brain areas associated with irony detection are the medial prefrontal cortex, inferior frontal gyrus (IFG), posterior superior temporal gyrus (pSTG), precuneus, and inferior parietal lobule, among others. This study aims to analyze the cognitive processes and neural correlates involved in irony detection in Mexican adults. Forty-five participants underwent a cognitive assessment and performed a contextual discrepancy task during fMRI acquisition. The behavioral results showed that the detection of nonliteral statements (irony, unrelated, and white lies) requires ToM and verbal abilities. In addition, white lies detection seemed to involve inhibitory control. Ironic statements were the hardest intention to detect, having the lowest percentage of classification and the slowest latency of classification. Irony detection involved brain areas associated with the ToM (i.e., precuneus) and language (i.e., IFG and pSTG) as was expected based on the results of previous studies. The detection of literal and unrelated statements recruited motor areas. No differential activation pattern was found for detection of white lies. Finally, a global perceptual processing style predicted the percent change in the BOLD signal in the IFG for all the nonliteral and literal statements.
Kirchhoff‐Helmholtz downward extrapolation in a layered medium with curved interfaces

SUMMARY In modelling applications, recursive Kirchhoff-Helmholtz extrapolation through a layered medium requires plane-wave decomposition and synthesis at the layer interfaces in order to take transmission effects into account. For inverse applications (downward extrapolation of the measured data into the subsurface), this plane-wave decomposition and synthesis is superfluous: transmission effects are automatically taken into account, since the extrapolated two-way (downgoing and upgoing) wavefield is continuous at layer interfaces. Two-way wavefield extrapolation, however, is very sensitive to errors in the model of the layered medium. Therefore, in practice one-way extrapolation schemes are preferred. It appears that for backward extrapolation of the primary upgoing wavefield, the recursive Kirchhoff-Helmholtz approach again accounts automatically for transmission effects at the layer interfaces. This approach is particularly attractive for situations where the contrasts at the layer interfaces are high.
A robust and new simple control strategy for a class of nonlinear power systems: induction and servomotors

In this paper, a robust backstepping controller is presented for position tracking of a class of servomotors. It has been shown by mathematical proof that the closed-loop system with the proposed controller has global asymptotic stability in the presence of structured and unstructured uncertainties, and external disturbances. In the following sections of this paper, to remove the undesirable phenomenon of chattering in the proposed control input, using a Takagi-Sugeno-Kang fuzzy system a robust fuzzy backstepping controller is designed that does not suffer from the undesirable phenomenon of chattering. To investigate the performance of the proposed controller, an induction motor and a DC motor with uncertainties are used as case studies. In the simulation phase, to provide essential challenges for the proposed controllers, simulations have been implemented in two steps. The results of these simulations show that the proposed approaches are very robust in the presence of parametric uncertainties, especially in the presence of external disturbances. In the design of a robust fuzzy controller, practical implementation considerations are taken into account in a way where the control input has a low computational burden.
NUCLEATION OF CARBON NANOTUBES WITHOUT PENTAGONAL RINGS

The unique one-dimensional structure of single-walled and multiwalled carbon nanotubes [1] depends critically upon a nucleation mechanism which somehow restricts graphitic growth to a single axis. The transient and extreme growth conditions of carbon nanotubes have obscured the mechanism of nucleation. Most hypothetical nucleation mechanisms invoke pentagon formation to produce a hemispherical graphitic cap, with the cap’s edges either open [2–4], attached to a substrate via a tubular segment [5–7], or mated with a second cap into a closed fullerene [8–10]. These models all require an abrupt transition from a regime favoring pentagon formation (when the cap is forming) to one that favors exclusively hexagon formation (when the tube is lengthening) once exactly six pentagons have formed [11]. Other models nucleate a nanotube from a 40-atom polyyne ring [12,13]. Unfortunately, such a large carbon ring is unlikely: carbon clusters change from simple rings to double rings and cages above 20 atoms [14]. Very recently, Bandow et al. have discovered that the temperature during synthesis controls the diameter of the nanotubes [15]. Since the diameter of a nanotube is fixed by its size at nucleation, these results provide rare experimental insight into nucleation itself. Here we propose a new nucleation model for carbon nanotubes which (1) contains only hexagonal rings within the tube nucleus and therefore does not require a transition from pentagon to exclusively hexagon formation, (2) can explain the temperature dependence of the nanotube diameter distribution, (3) accounts for the narrow diameter distribution of single-walled nanotubes, and (4) can explain the wider diameter distribution of multiwalled nanotubes. Carbon nanotube synthesis apparently requires a surface on either an electrode or a metallic particle [16]. Surfaces favor the growth of small flat graphitic patches. (Such graphitic patches can form even in much higher density environments [17].) Although it may be difficult to imagine a means by which a single graphitic patch could curl into the nucleus of a nanotube without the incorporation of pentagons to produce the needed curvature [18], we herein describe a natural kinetic pathway by which a two-layered graphitic patch can transform into the nucleus of a nanotube.
Improving the parallaxes of OH bearing Miras

Abstract We have carried out observations with the Very Long Baseline Array (VLBA) to measure the parallaxes of Mira variables and are able to improve the distance estimates significantly for a fraction of our sample (U Her, S CrB and RR Aql). This is predominantly because we have enhanced our technique by making use of nearby, in-beam calibrators. Additionally, the observing conditions have improved during the current solar minimum. The distances of these stars are of fundamental importance for studying the physical properties of Asymptotic Giant Branch (AGB) stars with high mass loss.
Linear programming relaxations, approximation algorithms and randomization: A unified view of covering problems

Our goal is to propose a unified method of approximation of integer programming problems. We show that the use of randomized rounding of linear programming relaxations of discrete optimization problems, but with nonlinear rounding functions and the use of dual information leads to a unified way of approximating NP-hard problems matching or improving upon the best known performance guarantees. We illustrate our methods using several examples: the set covering problem, facility location problems, network connectivity problems, survivable network design, the minimum multi-cut problem to name a few. In this way we illustrate a deeper connection between LP relaxations and approximation algorithms through the use of randomization.