Miracle-dz/UniFAR-FTUs huggingface dataset:
Variational assimilation of radar reflectivities in a cirrus model. II: Optimal initialization and model bias estimation

In this paper the microphysical model of cirrus clouds introduced in a related study is used to assimilate radar data. A variational approach is developed, based on a method of optimal estimation which makes use of the gradient information provided by the adjoint of the model to minimize a quadratic cost function. Multiple experiments to probe different solutions to the assimilation problem are conducted using both synthetic reflectivities and real observations. Various model and environment parameters are tested as control variables. Results indicate that specific humidity is a viable control variable at cloud levels. Even though this field is only indirectly related to the radar signal, information about the ambient humidity in which the cloud formed may be extracted from the radar reflectivities by using the cloud model in conjunction with the observations. The adjustment of the specific‐humidity profile brings the model solution closer to the observed values by increasing the crystal number concentration. Systematic errors in the prognostic variables are also estimated as part of the optimization process by including a model bias term in the cost function. This is equivalent to relaxing the assumption of ‘perfect’ model, and allows for better assimilation results when both model bias evaluation and optimal initialization are performed. Copyright © 2003 Royal Meteorological Society
The optimal smoothing estimators based on the Wiener-Hopf theory

Abstract It is well known that the Wiener-Hopf theory plays a fundamental role in estimation problems. In this paper, we derive the basic equations for the optimal smoothing estimators by using the Wiener-Hopf theory. The interrelation between the Wiener-Hopf theory and the innovation theory is also considered. Finally based on the basic equations three kinds of the smoothing estimators, that is, the fixed-point, fixed-interval, and fixed-lag smoothing estimators are derived.
Tornado Probability of Detection and Lead Time as a Function of Convective Mode and Environmental Parameters

AbstractThe ability to provide advanced warning on tornadoes can be impacted by variations in storm mode. This research evaluates 2 yr of National Weather Service (NWS) tornado warnings, verification reports, and radar-derived convective modes to appraise the ability of the NWS to warn across a variety of convective modes and environmental conditions. Several specific hypotheses are considered: (i) supercell morphologies are the easiest convective modes to warn for tornadoes and yield the greatest lead times, while tornadoes from more linear, nonsupercell convective modes, such as quasi-linear convective systems, are more difficult to warn for; (ii) parameters such as tornado distance from radar, population density, and tornado intensity (F scale) introduce significant and complex variability into warning statistics as a function of storm mode; and (iii) tornadoes from stronger storms, as measured by their mesocyclone strength (when present), convective available potential energy (CAPE), vertical wind she.
The Stefan problem with surface tension in the three dimensional case with spherical symmetry: nonexistence of the classical solution

The Stefan problem with surface tension in the three-dimensional case with spherical symmetry is considered. We first establish the existence and uniqueness of the classical solution with surface tension and kinetic undercooling effects for all time, and then pass to the limit as the kinetic undercooling tends to zero. The limiting solution is the global-in-time weak solution and the local-in-time classical solution for the Stefan problem with surface tension. This solution cannot be the global-in-time classical solution. If S(t) is the radius of a solid ball in a supercooled liquid, then (1) there exists at least one point t* of discontinuity of the function S(t): or (2) the continuous function S(t) cannot be absolutely continuous, and it maps some zero-measure set of (t*, T*) onto some set of Ω with a strictly positive measure.
Thalamocortical functional connectivity in youth with attention-deficit/hyperactivity disorder

Background: Few studies have empirically tested the relationships between anatomically defined thalamic nuclei and functionally defined cortical networks, and little is known about their implications in attention-deficit/hyperactivity disorder (ADHD). This study aimed to investigate the functional connectivity of the thalamus in youth with ADHD, using both anatomically and functionally defined thalamic seed regions. Methods: Resting-state functional MRIs obtained from the publicly available ADHD-200 database were analyzed. Thalamic seed regions were defined functionally and anatomically based on Yeo’s 7 resting-state-network parcellation atlas and the AAL3 atlas, respectively. Functional connectivity maps of the thalamus were extracted, and thalamocortical functional connectivity was compared between youth with and without ADHD. Results: Using the functionally defined seeds, significant group differences in thalamocortical functional connectivity and significant negative correlations between thalamocortical connectivity and ADHD symptom severity were observed within the boundaries of corresponding large-scale networks. However, in the analysis using the anatomically defined thalamic seeds, significant group differences in connectivity and significant positive correlations were observed outside the expected boundaries of major anatomic projections. The thalamocortical connectivity originating from the lateral geniculate nuclei of the thalamus was significantly correlated with age in youth with ADHD. Limitations: The small sample size and smaller proportion of girls were limiting factors. Conclusion: Thalamocortical functional connectivity based on the intrinsic network architecture of the brain appears to be clinically relevant in ADHD. The positive association between thalamocortical functional connectivity and ADHD symptom severity may represent a compensatory process recruiting an alternative neural network.
Optical polarization observations in Hogg 22 and NGC 6204

We present new ( UBVRI ) multicolor linear polarimetric data for 22 of the brightest stars in the area of the open clusters Hogg 22 and NGC 6204 to study the properties of the ISM (interstellar medium) toward these clusters and between them. The new data were incorporated in our data set of previous observations (Waldhausen et al. [CITE]), resulting in 28 observed stars in the region. Our data yield for NGC 6204 a mean polarization percentage of $P_{\lambda_{{\rm max}}}\sim1.8\%$, close to the polarization value produced by the ISM with normal efficiency ($P_{\lambda_{{\rm max}}} \sim 5 E_{B-V}$) with a color excess of $E_{B-V} =0.51$. Meanwhile for Hogg 22, located behind NGC 6204, the mean polarization is $P_{\lambda_{{\rm max}}}\sim 2.15\%$, lower than the expected value for the observed color excess of $E_{B-V} =0.68$ (Forbes et al. 1996) and the average efficiency of polarization for the interstellar dust. The mean angle of the polarization vectors of Hogg 22 is $\theta=44\fdg9$, which agrees with the expected angle produce by dust particles aligned in the direction of the Galactic Plane ($\theta=48^{\circ}$), while for NGC 6204 a lower value, $\theta=33\fdg7$, was found. Therefore, we believe that Hogg 22 is depolarized by the same dust that is polarizing NGC 6204, due to different orientations of the dust particles (and magnetic fields) that polarize the starlight.
NLRP3 inflammasome activation, metabolic danger signals and protein binding partners.

The NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome is an oligomeric complex that assembles in response to exogenous signals of pathogen infection and endogenous danger signals of non-microbial origin. When NLRP3 inflammasome assembly activates caspase-1, it promotes the maturation and release of the inflammatory cytokines interleukin-1B and IL-18. Aberrant activation of the NLRP3 inflammasome has been implicated in various diseases, including chronic inflammatory, metabolic, and cardiovascular diseases. The NLRP3 inflammasome can be activated through several principal mechanisms, including K+ efflux, lysosomal damage, and the production of mitochondrial reactive oxygen species. Interestingly, metabolic danger signals activate the NLRP3 inflammasome to induce metabolic diseases. NLRP3 contains three crucial domains: an N-terminal pyrin domain, a central nucleotide-binding domain, and a C-terminal leucine-rich-repeat domain. Protein-protein interactions act as a "pedal or brake" to control the activation of the NLRP3 inflammasome. In this review, we present the mechanisms underlying NLRP3 inflammasome activation after induction by metabolic danger signals or via the protein-protein interactions with NLRP3 that likely occur in metabolic diseases. Understanding these mechanisms will enable the development of specific inhibitors to treat NLRP3-related metabolic diseases.
Selecting relevant moderators with Bayesian regularized meta‐regression

When meta‐analyzing heterogeneous bodies of literature, meta‐regression can be used to account for potentially relevant between‐studies differences. A key challenge is that the number of candidate moderators is often high relative to the number of studies. This introduces risks of overfitting, spurious results, and model non‐convergence. To overcome these challenges, we introduce Bayesian Regularized Meta‐Analysis (BRMA), which selects relevant moderators from a larger set of candidates by shrinking small regression coefficients towards zero with regularizing (LASSO or horseshoe) priors. This method is suitable when there are many potential moderators, but it is not known beforehand which of them are relevant. A simulation study compared BRMA against state‐of‐the‐art random effects meta‐regression using restricted maximum likelihood (RMA). Results indicated that BRMA outperformed RMA on three metrics: BRMA had superior predictive performance, which means that the results generalized better; BRMA was better at rejecting irrelevant moderators, and worse at detecting true effects of relevant moderators, while the overall proportion of Type I and Type II errors was equivalent to RMA. BRMA regression coefficients were slightly biased towards zero (by design), but its residual heterogeneity estimates were less biased than those of RMA. BRMA performed well with as few as 20 studies, suggesting its suitability as a small sample solution. We present free open source software implementations in the R‐package pema (for penalized meta‐analysis) and in the stand‐alone statistical program JASP. An applied example demonstrates the use of the R‐package.
On the interdependence of ketone body oxidation, glycogen content, glycolysis and energy metabolism in the heart

In heart, glucose and glycolysis are important for anaplerosis and potentially therefore for d‐β‐hydroxybutyrate (βHB) oxidation. As a glucose store, glycogen may also furnish anaplerosis. We determined the effects of glycogen content on βHB oxidation and glycolytic rates, and their downstream effects on energetics, in the isolated rat heart. High glycogen (HG) and low glycogen (LG) containing hearts were perfused with 11 mM [5‐3H]glucose and/or 4 mM [14C]βHB to measure glycolytic rates or βHB oxidation, respectively, then freeze‐clamped for glycogen and metabolomic analyses. Free cytosolic [NAD+]/[NADH] and mitochondrial [Q+]/[QH2] ratios were estimated using the lactate dehydrogenase and succinate dehydrogenase reaction, respectively. Phosphocreatine (PCr) and inorganic phosphate (Pi) concentrations were measured using 31P‐nuclear magnetic resonance spectroscopy. Rates of βHB oxidation in LG hearts were half that in HG hearts, with βHB oxidation directly proportional to glycogen content. βHB oxidation decreased glycolysis in all hearts. Glycogenolysis in glycogen‐replete hearts perfused with βHB alone was twice that of hearts perfused with βHB and glucose, which had significantly higher levels of the glycolytic intermediates fructose 1,6‐bisphosphate and 3‐phosphoglycerate, and higher free cytosolic [NAD+]/[NADH]. βHB oxidation increased the Krebs cycle intermediates citrate, 2‐oxoglutarate and succinate, the total NADP/H pool, reduced mitochondrial [Q+]/[QH2], and increased the calculated free energy of ATP hydrolysis (∆GATP). Although βHB oxidation inhibited glycolysis, glycolytic intermediates were not depleted, and cytosolic free NAD remained oxidised. βHB oxidation alone increased Krebs cycle intermediates, reduced mitochondrial Q and increased ∆GATP. We conclude that glycogen facilitates cardiac βHB oxidation by anaplerosis.
Machine learning estimation of crude oil viscosity as function of API, temperature, and oil composition: Model optimization and design space

Measurement of viscosity of crude oil is critical for reservoir simulators. Computational modeling is a useful tool for correlation of crude oil viscosity to reservoir conditions such as pressure, temperature, and fluid compositions. In this work, multiple distinct models are applied to the available dataset to predict heavy-oil viscosity as function of a variety of process parameters and oil properties. The computational techniques utilized in this work are Decision Tree (DT), MLP, and GRNN which were utilized in estimation of heavy crude oil samples collected from middle eastern oil fields. For the estimation of viscosity, the firefly algorithm (FA) was employed to optimize the hyper-parameters of the machine learning models. The RMSE error rates for the final models of DT, MLP, and GRNN are 40.52, 25.08, and 30.83, respectively. Also, the R2-scores are 0.921, 0. 978, and 0.933, respectively. Based on this and other criteria, MLP is chosen as the best model for this study in estimating the values of crude oil viscosity.
Structural optimization by multilevel decomposition

A method for decomposing an optimization problem into a set of subproblems and a coordination problem that preserves coupling between the subproblems is described. The decomposition is achieved by separating the structural element optimization subproblems from the assembled structural optimization problem. Each element optimization and optimum sensitivity analysis yields the cross-sectional dimensions that minimize a cumulative measure of the element constraint violation as a function of the elemental forces and stiffness. The assembled structural optimization produces the overall mass and stiffness distributions optimized for minimum total mass subject to constraints that include the cumulative measures of the element constraint violations extrapolated linearly with respect to the element forces and stiffnesses. The method is introduced as a special case of a multilevel, multidisciplinary system optimization and its algorithm is fully described for two-level optimization for structures assembled of finite elements of arbitrary type. Numerical results are given as an example of a framework to show that the decomposition method converges and yields results comparable to those obtained without decomposition. It is pointed out that optimization by decomposition should reduce the design time by allowing groups of engineers using different computers to work concurrently on the same large problem.
Thermoelectric properties of rapid hot pressed polycrystalline Ag1−xPb18SbTe20 synthesized from doping PbTe nanocrystals

Polycrystalline thermoelectric (TE) materials of n‐type and with compositions of Ag1−xPb18SbTe20 (x = 0, 0.1, 0.2) were prepared by rapid hot pressing from alloy powders, which were obtained by ball milling crystalline ingots. The ingots were synthesized from PbTe nanoparticles, made by solvothermal reactions, and Ag, Sb and Te powders via vacuum‐sealed melting in quartz ampoules. Through rapid hot pressing at 748 K for 15 min under 80 MPa, the polycrystalline samples possessed 95% relative densities with the average grain size of 5 µm. The electrical resistivity, Seebeck coefficient and thermal conductivity of the Ag1−xPb18SbTe20 (x = 0, 0.1, 0.2) samples were measured in the range from room temperature (RT) to 673 K. The thermal conductivity was dramatically decreased, caused by scattering of phonons from grain boundaries and interfaces. By optimizing the values of carrier concentration and carrier transference, the Ag1−xPb18SbTe20 (x = 0.2) sample achieved a maximum ZT value of 1.019 at 673 K.
Distribution of sonic plesio‐velocity in a compact bone sample

Since compact bone is demonstrably anisotropic and inhomogeneous, the measured quantities yield a plesio‐velocity rather than a true sonic velocity, which makes it difficult to compare velocity measurements among several bone samples. Distribution of the plesio‐velocity for 11 pairs of 2 mm thick specimens from a single mature bovine compact bone sample using 100‐ns well‐damped sonic pulses emitted by a 10‐mHz transducer show that anisotropy exists in both axial and transverse directions and must be associated with the local structure and composition. Changes in the same specimens when wet, dry, and rehydrated show an increase in velocity and anisotropy of the dry over the wet state. The plesio‐velocity is greater in the axial direction, along the bone axis, than in the transverse plane. The change in plesio‐velocity from wet to dry bone is greatest along the bone axis and least in the transverse plane. Changes in dimension, when the bone specimens were dried, show the bone sample to be anisotropic in thi.
Nonequilibrium volume plasma chemical processing

A review is presented of plasma chemical processes occurring in the volume part of electrical nonequilibrium discharges. The role of energetic electrons as initiators of chemical reactions in a cold background gas is discussed. Different discharge types of (glow, corona, silent, RF, and microwave discharges) are investigated with respect to their suitability for plasma processing. Emphasis is placed on the requirements of initiating and maintaining the discharge and, at the same time, optimizing plasma parameters for the desired chemical process. Using large-scale industrial ozone production as an example, the detailed process of discharge optimization is described. Other applications of volume plasma processing include other plasma chemical syntheses as well as decomposition processes such as flue gas treatment and hazardous waste disposal. The author only deals with plasmas which are not in equilibrium. >
Completely Spectral Collocation Solution of Radiative Heat Transfer in an Anisotropic Scattering Slab With a Graded Index Medium

A completely spectral collocation method (CSCM) is developed to solve radiative transfer equation in anisotropic scattering medium with graded index. Different from the Chebyshev collocation spectral method based on the discrete ordinates method (SP-DOM), the CSCM is used to discretize both the angular domain and the spatial domain of radiative transfer equation. In this approach, the angular derivative term and the integral term are approximated by the high order spectral collocation scheme instead of the low order finite difference approximations. Compared with those available data in literature, the CSCM has a good accuracy for a wide range of the extinction coefficient, the scattering albedo, the scattering phase function, the gradient of refractive index and the boundary emissivity. The CSCM can provide exponential convergence for the present problem. Meanwhile, the CSCM is much more economical than the SP-DOM. Moreover, for nonlinear anisotropic scattering and graded index medium with space-dependent albedo, the CSCM can provide smoother results and mitigate the ray effect. [DOI: 10.1115/1.4024990]
Length-of-Day Changes and Mountain Torque during El Nifio

Abstract Values of mountain pressure torque are calculated for the Rocky and Andes Mountains and for the Tibetan Plateau in order to evaluate their conuibufion to the observed anomalous length-of-day (LOD) and atmospheric angular momentum (AAM) change during the period from late January to mid-February 1983. A period of rapid increase in AAM and LOD is found to coincide with unusually high values of mountain torque on the Rocky Mountains, associated with a midcontinent high-pressure event and a sequence of Pacific frontal cyclone lows hitting California. A subsequent decrease in AAM is not correlated with mountain pressure torquesover the three regions tested, thus implicating other regions or other transfer mechanisms.
Environmental impacts of PV systems-ground-based vs. BIPV

This study is part of the ExternE programme of the European Commission on the external costs of the photovoltaic (PV) fuel cycle. The objective of this paper is the quantitative evaluation of the main environmental impacts of two selected PV power systems-a ground-based 1 MWp system in Toledo, Spain and a 40 kWp building integrated facade in Newcastle upon Tyne, NE England-using the methodology of life cycle analysis (LCA). Both systems use silicon wafer technology at present, but the Newcastle facade was also studied with the incorporation CdTe modules. The results of the LCA show that atmospheric emissions are the priority impacts with respect to the assessed PV power systems. Comparing Si wafer systems, the CO/sub 2/ emissions were 88 t/GWh for the Toledo PV plant and 143 t/GWh for the BIPV facade. If the facade had used electrodeposited CdTe, the CO/sub 2/ emissions would fall to about 50 t/GWh.
Angular momentum in general relativity I. Definition and asymptotic behaviour

Angular momentum in axisymmetric space-times is investigated. The conclusions lead to a general definition suitable for all asymptoticallyflat spaces which is valid both at infinity and on the event horizon of a black hole. This first paper restricts attention to considerations at infinity. Working in terms of the spin coefficient formalism, the field equations are solved asymptotically at large distances and the definition is evaluated. A conservation law is derived and finally the effect on the angular momentum of a supertranslation of the coordinates is discussed.