Miracle-dz/UniFAR-FTUs huggingface dataset:
A parametric acoustic instability in premixed flames

We present an experimental and theoretical investigation of some aspects of the coupling between a premixed laminar quasi-planar flame front and acoustic standing waves in tubes. A multidimensional instability of the front arises from its interaction with the oscillating field of acceleration. This instability can be described by the Clavin–Williams laminar wrinkled flame theory in which the periodic acceleration created by the acoustic field is added to the acceleration due to gravity. As first suggested by Markstein, the resulting equation can be reduced to the Mathieu equation for a parametric oscillator. A cellular instability appears with a finite excitation threshold. This instability is responsible for the spontaneous generation of intense acoustic oscillations observed elsewhere. The value of the acoustic field at the threshold of instability and the wavelength of the cellular structures are measured experimentally for propane flames and are found to be in good agreement with the calculated values. It is also seen, both experimentally and theoretically, that for certain amplitudes of pumping, the parametric mechanism can also stabilize an initially unstable system.
The structure and dynamics of the molecular envelope of M 2 56

M2 56 is a protoplanetary nebula (PPN) in which strong shocks are taking place, therefore, useful to study the post AGB wind interaction. It is well known that molecular observations allow studying the mass distribution of PPNe, even in those regions that have been recently shocked. We present high resolution maps of the emission of 12 CO J =2 1a ndJ =1 0i n M 2 56. Such maps show a bipolar, molecular nebula that extends 28 00 along the symmetry axis. The nebula is composed of two contiguous, incomplete shells located along the symmetry axis, which has an inclination of17 o with respect to the plane of the sky. Those empty lobes intersect in the center of the nebula, where there is a small and dense ring perpendicular to the axis. This central ring expands radially at about 8 km s 1 and seems to be the remnant of the circumstellar envelope of the AGB star, that has not been accelerated by the interaction with the fast post AGB jets. The radius of the central ring is of 4 10 16 cm, for a distance of 2.1 kpc (deduced from an analysis of the main properties of the object). At 4 10 17 cm from the nebular center, the tips of the lobes reach axial expansion velocities of200 km s 1 . W e have developed a model for the spatio kinematical distribution and the excitation conditions of the molecular gas in M 2 56. From the best tting of the observations with the predictions of the model for both lines, we have estimated the physical conditions of the molecular nebula. It is found that the density varies from 5 10 3 to 0:6 10 3 cm 3 from the nebular center to the lobe tips, and that the part of the lobes that has not been detected is probably composed of photodissociated gas, due to the eect of interstellar photons on low density regions. The rotational temperature is estimated to be approximately constant, 13 16 K. For the assumed geometry, a velocity eld composed by a dominant radial component plus an axial contribution has been deduced. The emission of both lines is found to be optically thin, and therefore probes the whole molecular gas, which has am ass of0.05M. The \scalar" momentum and the kinetic energy of the dierent regions of the molecular nebula have been calculated, nding that the high momentum won by the gas in the post AGB phase cannot have been supplied by the radiation pressure mechanism. Although the central star of M 2 56 is not very hot yet (20 000 K), this PPN has a large kinematical age, between 1000 yr and 1700 yr, in comparison with other PPNe that have hotter central stars. M 2 56 may not be a typical PPN, but an intermediate object between the known low mass post AGB nebulae and the standard PPNe.
A maximum-entropy approach to fuzzy clustering

In this paper, we propose a new approach to fuzzy clustering by means of a maximum-entropy inference (MEI) method. The resulting formulas have a better form and clearer physical meaning than those obtained by means of the fuzzy c-means (FCM) method. In order to solve the cluster validity problem, we introduce a structure strength function as clustering criterion, which is valid for any membership assignments, thereby being capable of determining the plausible number of clusters according to our subjective requisition. With the proposed structure strength function, we also discuss global minimum problem in terms of simulated annealing. Finally, we simulate a numerical example to demonstrate the approach discussed, and compare our results with those obtained by the traditional approaches. <<ETX>>
MATISSE-v2.0: new functionalities and comparison with MODIS satellite images

MATISSE (Advanced Modeling of the Earth for Environment and Scenes Simulation) is an infrared background scene generator developed for computing natural background spectral radiance images. The code also provides atmospheric radiatives quantities along lines of sight. Spectral bandwidth ranges from 0.4 to 14 μm. Natural backgrounds include atmosphere, sea, land and high and low altitude clouds. The new version MATISSE-v2.0, released this year, has been designed to treat spatial multi resolution in the generated images in order to be able to reach metric spatial variability in pixels footprints. Moreover, MATISSE-v2.0 includes a new sea surface radiance model (water waves and surface optical properties) which depends on wind speed, wind direction and fetch value. Preliminary validations using radiometric measurements have been conducted concerning sea radiances and give promising results. In order to go further in the validation process of MATISSE-v2.0, comparisons with MODIS satellite images have been led. The results of comparing the simulated MATISSE images radiances with the MODIS observations show that the code is performing well. This paper gives a description of MATISSE-v2.0 new functionalities and focus on first results on comparison between MATISSE/MODIS images radiances.
Post-Buckling of Geometrically Imperfect Plates

Explicit expressions are derived for the collapse and elastic post-buckling of simply supported, geometrically imperfect plates with stress-free edges. For the purposes of design, such plates can be taken as representative of the stiffened compression elements of thin-walled structural sections. Different generalized geometric imperfection parameters are studied and the effects compared to established test data obtained from cold-formed steel sections subjected to either bending or compression. For these sections a suitable and completely general parameter describing the imperfection amplitude, e\d0t, of a plate of thickness t is shown to be e\d0=0. 2σ\dy/σ\Dcr\N in which σ\dy is the yield strength of the plate material; σ\Dcr\N is the theoretical local buckling stress of the equivalent ideal plate and is a direct function of its width to thickness ratio. This parameter is recommended for the design of cold-formed steel sections against local buckling.
Interest Rates, Money, and Fed Monetary Policy in a Markov-Switching Bayesian VAR

Abstract This paper evaluates the roles of short- and long-term private and government interest rates and inside and outside money in the monetary transmission mechanism. With money and credit markets present, changes in monetary policy set off a chain of relative price and portfolio adjustments affecting output and prices. I study interest rate and money supply rules within this monetary transmission mechanism by estimating several Markov-switching Bayesian vector autoregressions (MS-BVARs) on a quarterly U.S. sample from 1960 to 2018. The best-fit MS-BVAR restricts MS to the impact and lag coefficients of the monetary policy and money demand regressions as well as to the stochastic volatilities (SVs) of the structural shocks. Estimates of this MS-BVAR yield evidence of a SV regime which coincides with NBER-dated recessions. This MS-BVAR also identifies a regime switch in the Fed’s interest rate rule and banks’ demand for outside money around the dot-com bust of 2000 and again from the 2007–2009 recession and financial crisis to the end of the sample. Counterfactual simulations show the 2007–2009 recession and financial crisis would have not been as deep and long-lasting if the fed funds rate had been as low as −8 % in 2009 and remained negative from 2010 through 2016.
Anomalous dissipation for 1/5-Hölder Euler flows

Recently the second and fourth authors developed an iterative scheme for obtaining rough solutions of the 3D incompressible Euler equations in Holder spaces. The motivation comes from Onsager's conjecture. The construction involves a superposition of weakly interacting perturbed Beltrami flows on infinitely many scales. An obstruction to better regularity arises from the errors in the linear transport of a fast periodic flow by a slow velocity field. In a recent paper the third author has improved upon the methods, introducing some novel ideas on how to deal with this obstruction, thereby reaching a better Holder exponent-albeit weaker than the one conjectured by Onsager. In this paper we give a shorter proof of this final result, adhering more to the original scheme of the second and fourth authors and introducing some new devices. More precisely we show that for any positive e, there exist periodic solutions of the 3D incompressible Euler equations that dissipate the total kinetic energy and belong to the Holder class $C^{1/5-\epsilon}$.
International Journal of Data and Network Science

Small and Medium Enterprises (SMEs) have a central role in the Indonesian economy. SMEs are a driver of the Indonesian economy and non-oil exports and have a significant role in absorbing labor. The SME sector in Indonesia generally has several obstacles, one of which is marketing constraints. The ability to build and communicate brands to customers tends to be low, so it has not been able to bind customers and affect the marketing performance of SMEs. This ability during the pandemic has worsened, as can be seen from the deteriorating marketing performance of SMEs. This study attempts to fill the research gap between digital marketing and marketing performance. This study offers the concept of Brand Articulating Capability to bridge the gap between Digital Marketing in increasing Marketing Performance. Three hypotheses were developed and tested in a sample frame of 230 SMEs in South Sulawesi, Indonesia. The analysis was carried out using Structural Equation Modelling to test the research. The study's findings support the model using the following variables: Digital Marketing has a significant effect on Marketing Performance, Digital Marketing has a significant impact on Brand Articulating Capability, and the Brand Articulating Capability variable has a mediating and strategic role in improving marketing performance.
Intraseasonal and Interannual Variations of Tropical Convection: A Possible Link between the 40–50 Day Oscillation and ENSO?

Abstract Intraseasonal and interannual variations of tropical convection are studied using 12 years of NOAA outgoing longwave radiation (OLR) data. The spatial patterns of OLR variance in the 1–5 day, 20–70 day and longer-than-180 day bands am examined separately for the northern summer (May–October) and winter (November&ndash April). In the 1–5 day band, the most prominent features are the Pacific and Atlantic ITCZs during the northern summer and the large variability over the western Pacific and the tropical continents during the northern winter. For the time scales beyond 10 days, it was found that the maximum variance shifts north and south of the equator from summer to winter but is generally located between 20°S and 20°N in the longitudinal sector between the Indian and Pacific oceans. Over the Indian Ocean and the western Pacific, variations with 30–60 day period are most pronounced. In the central and eastern Pacific variations with periods over one year are more prevalent. The natural variability.
Gut microbiota alterations after switching from a protease inhibitor or efavirenz to raltegravir in a randomized, controlled study

Objective: To study gut microbiota before and 24 weeks after a single antiretroviral agent switch. Design: HIV-positive patients with efavirenz (EFV) or a protease inhibitor (PI)-based antiretroviral therapy (ART) were randomized to switch EFV or PI to raltegravir (RAL group, n = 19) or to continue unchanged ART (EFV/PI group, n = 22). Age and weight-matched HIV-negative participants (n = 10) were included for comparison. Methods: Microbiota was analyzed using 16S rRNA sequencing. Serum intestinal fatty acid-binding protein (I-FABP) and serum lipopolysaccharide-binding protein (LBP) were measured as gut permeability markers. Three-day food diaries were collected. Results: At week 24, microbiota diversity (Chao1 index) was higher in RAL than the EFV/PI group (P = 0.014), and RAL group did not differ from HIV-negative participants. In subgroup analysis switching from EFV (P = 0.043), but not from a PI to RAL increased Chao1. At week 24, RAL and EFV/PI group differed in the relative abundance of Prevotella 9 (higher in RAL, P = 0.01), Phascolarctobacterium and Bacteroides (lower in RAL, P = 0.01 and P = 0.03). Dietary intakes did not change during the study and do not explain microbiota differences. Also, I-FABP and LBP remained unchanged. Conclusion: Here we demonstrate that a single ART agent switch caused microbiota alterations, most importantly, an increase in diversity with EFV to RAL switch. Previously, we reported weight gain, yet reduced inflammation in this cohort. The observed microbiota differences between RAL and EFV/PI groups may be associated with reduced inflammation and/or increase in weight. Further studies are needed to evaluate inflammatory and metabolic capacity of microbiota with ART switches.
Clinically meaningful changes in efficacy outcomes in chronic rhinosinusitis with nasal polyposis

Purpose of review Chronic rhinosinusitis with nasal polyps (CRSwNP) carries a high disease burden, and many studies have been done investigating the efficacy of various medical and surgical therapies. However, outcome metrics have varied across these studies, making it difficult to compare therapeutic efficacy on a large scale. In this article, we discuss various outcome metrics used across prior studies as well as the relationship between these measures. Recent findings Outcome metrics in CRSwNP studies include both clinically assessed and patient-reported outcome measures (PROMs). The former includes olfaction testing, scoring systems based on imaging and endoscopic evaluation, and histopathological and immunohistochemical evaluation of sinus tissue, and the latter includes quality-of-life instruments, symptom severity scales, and disease-control instruments. Recent studies evaluating the efficacy of new biologics have used a combination of both types of metrics. Summary Both clinical metrics and patient-reported outcomes provide utility in evaluating disease severity and control in patients with CRSwNP, although there are nuances when comparing therapies in this population as patients with CRSwNP are heterogeneous and may have symptoms across several domains. However, PROMs in conjunction with clinical metrics provide useful information to assess patient symptoms and response to interventions.
Persistence of envelopes in different CD4+ T-cell subsets in antiretroviral therapy-suppressed people with HIV

Objectives: Despite suppressive antiretroviral therapy (ART), HIV can persist in a diverse range of CD4+ T-cell subsets. Through longitudinal env sampling from people with HIV (PWH) on ART, we characterized the persistence and phenotypic properties of HIV envs over two time-points (T1 and T2). Methods: Longitudinal blood and lymphoid tissue samples were obtained from eight PWH on suppressive ART. Single genome amplification (SGA) was performed on env to understand the genetic diversity and degree of clonal expansions over time. A subset of envs were used to generate pseudovirus particles to assess sensitivity to autologous plasma IgG and broadly neutralizing antibodies (bNAbs). Results: Identical env sequences indicating clonal expansion persisted between T1 and T2 and within multiple T-cell subsets. At both time-points, CXCR4-tropic (X4) Envs were more prevalent in naive and central memory cells; the proportion of X4 Envs did not significantly change in each subset between T1 and T2. Autologous purified plasma IgG showed variable neutralization of Envs, with no significant difference in neutralization between R5 and X4 Envs. X4 Envs were more sensitive to neutralization with clinical bNAbs, with CD4-binding site bNAbs demonstrating high breadth and potency against Envs. Conclusion: Our data suggest the viral reservoir in PWH on ART was predominantly maintained over time through proliferation and potentially differentiation of infected cells. We found the humoral immune response to Envs within the latent reservoir was variable between PWH. Finally, we identified coreceptor usage can influence bNAb sensitivity and may need to be considered for future bNAb immunotherapy approaches.
SATBench: A Benchmark of the Human Speed-Accuracy Tradeoff in Recognizing Objects

People take a variable amount of time, 0.1 to 10 s, to recognize an object. The 1 reaction time depends on the stimulus and task, and people can trade off speed 2 for accuracy. That tradeoff is a crucial human skill. Neural networks exhibit high 3 accuracy in object recognition, but most current models cannot dynamically adapt 4 to respond with less computation, which is a problem in time-sensitive applications 5 like driving. Towards the goal of using networks to model how people recognize 6 objects, we here present a benchmark dataset (with model ﬁts) of the human speed-7 accuracy tradeoff (SAT) in recognizing CIFAR-10 [1] and STL-10 [2] images. In 8 each trial, a beep, indicating the desired reaction time, sounds at a ﬁxed delay after 9 the target onset, and the observer’s response counts only if it occurs near the time 10 of the beep. With practice, observers quickly learn to respond at the time of the 11 beep. In a series of blocks, we test many beep latencies, i.e., reaction times. We 12 observe that human accuracy increases with reaction time, and we compare its 13 characteristics with the behavior of several dynamic neural networks that can trade 14 off speed and accuracy. After limiting the network resources and adding image 15 perturbations (grayscale conversion, noise, blur) to bring the two observers (human 16 and network) into the same accuracy range, we show that humans and networks
THE LEGEND OF THERMO GAME BASED COMPUTER AS LEARNING MEDIA ON THERMOCHEMISTRY FOR IMPROVING CURIOSITY ATTITUDE

This research aims to obtain the learning media as a game that feasible for Thermochemistry matter. This study used Research and Development type with Borg and Gall model. This model has ten stages which are useful for producing a viable learning media. Feasible learning media require validity, practicality, and effectiveness. The validity score average on content and construct obtained 95.14% which very valid category. The media practicality assessment by students' responses using a questionnaire and obtained 86.26% which very practical category. The results of the effectiveness based on curiosity assessment of learning students obtained 90.33% which very effective category. The significant value of the pretest results obtained 0.200 and posttest results obtained 0.128 which is more than 0.05 so the data are normally distributed. In the Paired Sample t-Test obtained a significant value of 0,000 which is less than 0.05 so there is a significant difference between the pretest and posttest scores. Based on the explanation above, it is obtained a learning media as a game that feasible for Thermochemistry matter.
Optical Limiting via Plasmonic Parametric Absorbers

Optical sensors are increasingly prevalent devices whose costs tend to increase with their sensitivity. A hike in sensitivity is typically associated with fragility, rendering expensive devices vulnerable to threats of high intensity illumination. These potential costs and even security risks have generated interest in devices that maintain linear transparency under tolerable levels of illumination, but can quickly convert to opaque when a threshold is exceeded. Such a device is deemed an optical limiter. Copious amounts of research have been performed over the last few decades on optical nonlinearities and their efficacy in limiting. This work provides an overview of the existing literature and evaluates the applicability of known limiting materials to threats that vary in both temporal and spectral width. Additionally, we introduce the concept of plasmonic parametric resonance (PPR) and its potential for devising a new limiting material, the plasmonic parametric absorber (PPA). We show that this novel material exhibits a reverse saturable absorption behavior and promises to be an effective tool in the kit of optical limiter design.
Space Telescope Imaging Spectrograph Ultraviolet Spectroscopy of Early B Supergiants in M31

We analyze Space Telescope Imaging Spectrograph (STIS) spectra in the 1150-1700 Å wavelength range obtained for six early B supergiants in the neighboring galaxy M31. Because of their likely high (nearly solar) abundance, these stars were originally chosen to be directly comparable to their Galactic counterparts and represent a much needed addition to our current sample of B-type supergiants, in our efforts to study the dependence of the wind momentum-luminosity relationship on spectral type and metallicity. As a first step to determine wind momenta we fit the P Cygni profiles of the resonance lines of N V, Si IV, and C IV with standard methods and derive terminal velocities for all of the STIS targets. From these lines we also derive ionic stellar wind column densities. Our results are compared with those obtained previously in Galactic supergiants and confirm earlier claims of "normal" wind line intensities and terminal velocities in M31. For one-half of the sample we find evidence for an enhanced maximum turbulent velocity when compared to Galactic counterparts.
Self-similarity in piecewise isometric systems

This paper deals with piecewise isometries and their scaling properties. We aim to present a general framework in which piecewise isometric dynamical systems can be fully or partially renormalized. We precisely describe the dynamics on fractal invariant sets by means of a conjugacy with substitution dynamical systems and Bratteli diagrams. We describe their geometrical properties in terms of graph-directed constructions and we compute their Hausdorff dimension. We also present an example of application to a continuous family of piecewise rotations.
The prospective mathematics teachers’ thought processes and views about using problem-based learning in statistics education

The purpose of this study is to determine prospective mathematics teachers’ views about using problem-based learning (PBL) in statistics teaching and to examine their thought processes. It is a qualitative study conducted with 15 prospective mathematics teachers from a state university in Turkey. The data were collected via participant observation and semi-structured interviews. To determine their thought processes, all PBL sessions and interviews were audio-taped. The analysis of the data suggests that the participants liked the PBL application. They had overall positive views regarding PBL, although there were some stated concerns regarding the applicability of PBL in Turkish schools due to insufficient means. The findings also suggest that PBL sessions enhanced their self-expressions; hence, their thought processes had developed in the course of PBL application. We hope that this study will contribute to future studies about the use of PBL method in statistics teaching.