Miracle-dz/UniFAR-FTUs huggingface dataset:
L/sub 2/ disturbance attenuation and performance bounds for linear non-minimum phase square invertible systems

A complete solution, including explicit performance bounds, is provided, to the problem of finding a state feedback that asymptotically stabilizes the system and achieves disturbance attenuation (in the sense of the L/sub 2/ gain), for square invertible linear systems. The solution exposes the intimate relationship between the unstable forced zero dynamics of the system and the ability to disturbance attenuate. Further, we derive, using relatively simple techniques a sufficient condition for almost disturbance decoupling with a stability margin. The condition thus found actually coincides with the condition given by Willems (1981) and Weiland and Willems (1989), which was proven to be necessary and sufficient.
Experimental investigation of domain expansion speeds in MAMMOS

Summary form only given. Since high data rates are critical to the success of MAMMOS (magnetically amplified magneto-optical disc system) technology, expansion and collapse speeds of magnetic domains have become a topic of recent interest. To date, the expansion speed in a MAMMOS system has not been directly measured. One way to measure the speed, is by observing the rise and fall times of the magneto-optic readback signal and inferring wall velocities from these times. To measure the rise and fall times experimentally, a MAMMOS system with a 658 nm laser and 0.6 NA lens was equipped with a high-speed photo detector recently developed at Philips. Using this system, MAMMOS readout signals were collected for various laser powers and readout fields using a LaCroy DDA-110 to sample the photo detector output at 2 GHz.
Cusp field‐aligned currents and ion outflows

On September 24 and 25, 1998, the Polar spacecraft observed intense outflows of terrestrial ions in association with the passage of an interplanetary shock and coronal mass ejection. The orbit of the Fast Auroral Snapshot (FAST) Explorer was in the noon-midnight meridian during this ion outflow event, and FAST passed through the day side cusp region at ∼4000 km altitude every 2.2 hours. FAST was therefore able to monitor the ion outflows subsequently observed by Polar. We show that while the outflows were more intense after the shock passage, the overall particle and field signatures within the cusp region were qualitatively similar both before and after the shock passage. FAST observations show that the cusp particle precipitation marks the lower latitude leg of a pair of field-aligned currents and further, that both field-aligned current sheets appear to be on open field lines. Moreover, the polarity of the cusp currents is controlled by the polarity of the interplanetary magnetic field (IMF) y-component, such that the magnetic field perturbation associated with the pair of cusp currents is in the same direction as the IMF By. This is a consequence of the reconnection of cusp-region field lines at the magnetopause, with the flux transport resulting in electromagnetic energy being transmitted along field lines to the ionosphere as Poynting flux. We show that this Poynting flux can be as high as 120 mW m−2 (120 ergs cm−2 s−1) at FAST altitudes (∼500 mW m−2 at ionospheric altitudes), presumably because of the strong IMF By (∼40 nT), and is the dominant energy input to the cusp-region ionosphere. Furthermore, we find that the peak ion outflow flux is correlated with the peak downward Poynting flux, although only a few passes through the cusp centered around the time of the shock passage were used to determine this correlation. The energy carried by Poynting flux is dissipated as heat within the ionosphere, through Joule dissipation. The heating will tend to increase the ionospheric scale height, allowing greater access of ionospheric ions to the altitudes where transverse ion heating via ELF waves can occur. Thus electromagnetic energy supplied by the transport of reconnected magnetic flux is the essential first step in a multistep process that enhances the outflow of ionospheric plasma in the dayside cusp.
Thermodynamic Analysis of Al 2 O 3 –Water Nanoﬂuid Flow in an Open Cavity Under Pulsating Inlet Condition

This paper is meant to investigate the entropy generation for mixed convective pulsating nanoﬂuid ﬂow in a channel with an open cavity, heated from left side (assisting ﬂow) with uniform temperature distribution. The Navier–Stokes and energy equations are numerically solved by the Finite Volume Method. The effects of parameters such as Reynolds number ( Re ), volume fraction of solid nanoparticles ( ϕ ) and frequency ( St ) and amplitude ( A ) of the pulsation on the ﬂow and temperature ﬁelds as well as heat transfer and entropy generation rates are examined. Results show that the ﬂuid ﬂow, the temperature distribution, the heat transfer characteristics and the entropy generation are considerably affected by variations of these parameters. The pulsation enhances the heat transfer rates. The maximum enhancement is obtained with an optimum pulsation frequency which depends on the studied case. An enhancement of heat transfer rate with minimum entropy generation is obtained in the range of Strouhal number [0.6,1] for Re = 100; [0.4,1] for Re = 200 and [0.3,1] for Re = 300.
Sensitivity of Tropical West Pacific Oceanic Squall Lines to Tropospheric Wind and Moisture Profiles

Abstract Two-dimensional experiments using the Goddard Cumulus Ensemble model are performed in order to examine the influence of environmental profiles of wind and humidity on the dynamical and microphysical structure of mesoscale convective systems (MCSs) over the tropical oceans. The initial environments used in this study are derived from the results of a cluster analysis of the TOGA COARE sounding data. The model data are analyzed with methods and measurements similar to those used in observational studies. Experiments to test the sensitivity of MCSs to the thermodynamic profile focus on the role of humidity in the free troposphere. In the experiments, a constant amount of relative humidity is added to every level above the boundary layer. As humidity is increased, model storms transition from weak, unsteady systems with little precipitation to strong, upshear-tilted systems with copious rainfall. This behavior is hypothesized to be the result of the entrainment of environmental air into the updraft c.
Vortex dynamics in patterned ferromagnetic ellipses

The dynamics of individual magnetic vortices and vortex pairs confined in lithographically defined ferromagnetic ellipses were measured using a microwave reflection technique. Resonance frequencies were detected in the subgigahertz range for Ni80Fe20 (Permalloy) ellipses ranging in size from 3 by 1. 5μm to 1 by 0. 5μm, 40nm in thickness. Micromagnetic simulations indicate that the single mode observed for one vortex is a translational mode and that the two eigenmodes associated with a vortex pair correspond to coupled translational modes of vortices with parallel or antiparallel core polarizations. The single-vortex resonance scales inversely with the ellipse size, in agreement with the simulations and analytical theory.
Driving Forces of Extreme Updrafts Associated With Convective Bursts in the Eyewall of a Simulated Tropical Cyclone

Many studies have indicated that convective bursts (CBs) are closely related to tropical cyclone (TC) intensification, but few studies have been conducted on the mechanisms that control the formation and evolution of CBs. In this study, the 1‐min output data of a simulated TC are used to understand the convective extreme updrafts of CBs in the TC eyewall. Three different reference states including the local square‐area mean (LAM), the lower wavenumber‐components mean (WNM), and the arc‐area mean (ArcM) are used to calculate the driving forces of convective extreme updrafts. Contrary to the WNM and ArcM reference states, the LAM reference state struggles to capture realistic basic state structures. The LAM reference state can be modified through the inclusion of the mean hydrometeor mixing ratio in the basic state to produce physically consistent forcing in relation to the simulated convective extreme updrafts. The simulated convective extreme updrafts in the TC eyewall exhibit two peaks at middle and upper levels, respectively, since the effect of hydrometeor loading, decelerates the air parcels between the updraft maxima. While the positive buoyancy makes air parcels in the CBs accelerate at middle levels, in agreement with previous studies, it is found that, at the upper levels, both the positive buoyancy and the upward vertical perturbation pressure gradient force accelerate the air parcels. This study suggests that the vertical perturbation pressure gradient force also plays an important role in the formation of CBs in the TC eyewall.
Heater-induced cavities as optical tracers of plasma drifts

A new technique is used to measure F region plasma drifts at night. The technique involves observing the motion of density cavities generated by high-power radio waves in the ionosphere. The airglow signature of the cavities is recorded and analyzed with a ground-based, low-light-level imaging system. The heater-induced cavity optical tracer method is capable of providing velocity information with an error less than 1 m/s and a time resolution better than 60 s.
Existence and Stabilization of Solutions to the Phase-Field Model with Memory

A phase field model is considered when the classical Fourier law is replaced by the linearized GurtinPipkin constitutive assumption for the heat flux. The resulting system of partial differential equations consists in a Volterra integro-differential equation coupled with a nonlinear parabolic inclusion. The initial and boundary value problem with homogeneous Neumann boundary conditions is investigated for a kernel of positive type. Results on the long-time behavior of solutions are obtained in a quite general setting.
Statistical ring current of Saturn

[1] The statistical ring current of Saturn has been determined from the curl of the median magnetic field derived from over 5 years of observations of the Cassini magnetometer. The main issue addressed here is the calculation of the statistical ring current of Saturn by directly computing, for the first time, the symmetrical part of the ring current J from the Maxwell equation ∇ × B = μ0J from assembling the perturbation magnetic field B from 2004 through 2010. This study validates previous studies, based on fewer data and not using ∇ × B, and shows that the ring current flows eastward (in the +ϕ or corotation direction) and extends from ∼3 RS to at least ∼20 RS (1 RS = 60,268 km), which is the vicinity of the dayside magnetopause; that the ring current has a peak strength of ∼75 pA/m2 at ∼9.5 RS; and that the ring current has a half-width of ∼1.5 RS. Two outcomes of this study are that the ring current bends northward, as suggested by the “bowl” model of Saturn's plasma sheet, and that the total ring current is 9.2 ± 1.0 MA. In the context of future endeavors, the statistical ring current presented here can be used for calculations of the magnetic field of Saturn for particle drifts, field line mapping, and J × B force.
Non-Dexamethasone Corticosteroid Therapy’s Effect on COVID-19 Prognosis in Cancer Patients: A Retrospective Study

Background: Anti-inflammatory corticosteroids are used in cancer treatment and COVID-19 infections. Data on the impact of non-dexamethasone corticosteroids on COVID-19 infection severity in cancer patients are minimal. This study investigates if corticosteroid treatment affects the disease severity in adult cancer patients. Methods: A total of 116 COVID-19-infected cancer patients on hydrocortisone (H) or prednisone (P) were compared to 343 untreated patients. The study included patients who received corticosteroids before (B), after (A), or both before and after (B and A) COVID-19 infections. Ventilation support, hospitalization and mortality were investigated. Results: Our data showed that a significantly greater number of patients taking H or P required ventilation support and hospitalization and that mortality rates were higher than the control group. Patients who received H or P after COVID-19 infection had a significantly worse prognosis than the other sub-groups and the control group. Conclusion: Corticosteroids impacted cancer patients’ COVID-19 prognosis. Despite the limited sample size, H- and P-treated patients’ corticosteroids performed worse than the control, especially if treatments were received after COVID-19 infection. Hence, when a cancer patient already on H or P treatment is diagnosed with COVID-19, we recommend switching to a steroid treatment as suggested by international guidelines.
Vibration of a Bimodulus Thick Plate According to a Higher-Order Shear Deformation Theory

Equations of motion of a simply supported rectangular bimodulus thick plate in which the higher-order shear deformation terms are included are derived. The governing equations obtained using the average stress method are solved in exact form. The natural frequencies are compared with the previous results obtained for ordinary thick plates, and with the neutral surface locations and natural frequencies of bimodular plates. From those comparisons, the effects of higher-order shear deformation terms on the neutral surface locations and the natural frequencies can be observed. Also, the percentage error sense improvement by higher-order deformation terms can be reduced from 1.4 to 0.09%.
Discriminating different scenarios to account for the PAMELA and ATIC data by synchrotron and IC radiation

The excesses of the cosmic positron fraction recently measured by PAMELA and the electron spectra by ATIC, PPB-BETS, Fermi and H.E. S.S. indicate the existence of primary electron and positron sources. The possible explanations including dark matter annihilation, decay, and astrophysical origin like pulsars. In this work we show that these three scenarios can all explain the experimental results of the cosmic $e^\pm$ excess. However, it may be difficult to discriminate these different scenarios by the local measurements of electrons and positrons. We propose possible discriminations among these scenarios through the synchrotron and inverse Compton radiation of the primary electrons/positrons from the region close to the Galactic center. Taking typical configurations, we find the three scenarios predict quite different spectra and skymaps of the synchrotron and inverse Compton radiation, though there are relatively large uncertainties. The most prominent differences come from the energy band $10^4\sim 10^9$ MHz for synchrotron emission and $\gtrsim 10$ GeV for inverse Compton emission. It might be able to discriminate at least the annihilating dark matter scenario from the other two given the high precision synchrotron and diffuse $\gamma$-ray skymaps in the future.
Acoustic Irritation Threshold of Peking Ducks and Other Domestic and Wild Fowl

When exposed to sounds of sufficient intensity Peking ducks respond in a characteristic manner combining head shaking and tail twitching. The response rate (number of responses per unit‐time) increases with intensity up to a certain level, but falls with further increase in intensity. There is no response at intensities lower than a certain critical value which may therefore be described as the irritation threshold. Prolonged exposure to sound leads to a more or less exponential drop in response rate but recovery is rapid during rest periods. Measurements on about thirty ducks indicate that the threshold has a broad minimum at about 500 cps and the average value at this frequency is about 70 db [all sound pressure levels are given with respect to 0.0002 d/cm2] with a range of 65–85 db. There is some indication that the threshold is slightly lower for warble tones. At 15 and 18 kc no consistent responses have been obtained up to 115 and 120 db, respectively. Similar experiments with chickens and geese show.
Complexity results for some classes of strategic games

Game theory is a branch of applied mathematics studying the interaction of self-interested entities, so-called agents. Its central objects of study are games, mathematical models of real-world interaction, and solution concepts that single out certain outcomes of a game that are meaningful in some way. The solutions thus produced can then be viewed both from a descriptive and from a normative perspective. The rise of the Internet as a computational platform where a substantial part of today's strategic interaction takes place has spurred additional interest in game theory as an analytical tool, and has brought it to the attention of a wider audience in computer science. An important aspect of real-world decision-making, and one that has received only little attention in the early days of game theory, is that agents may be subject to resource constraints. The young field of algorithmic game theory has set out to address this shortcoming using techniques from computer science, and in particular from computational complexity theory. One of the defining problems of algorithmic game theory concerns the computation of solution concepts. Finding a Nash equilibrium, for example, i.e., an outcome where no single agent can gain by changing his strategy, was considered one of the most important problems on the boundary of P, the complexity class commonly associated with efficient computation, until it was recently shown complete for the class PPAD. This rather negative result for general games has not settled the question, however, but immediately raises several new ones: First, can Nash equilibria be approximated, i.e., is it possible to efficiently find a solution such that the potential gain from a unilateral deviation is small? Second, are there interesting classes of games that do allow for an exact solution to be computed efficiently? Third, are there alternative solution concepts that are computationally tractable, and how does the value of solutions selected by these concepts compare to those selected by established solution concepts? The work reported in this thesis is part of the effort to answer the latter two questions. We study the complexity of well-known solution concepts, like Nash equilibrium and iterated dominance, in various classes of games that are both natural and practically relevant: ranking games, where outcomes are rankings of the players; anonymous games, where players do not distinguish between the other players in the game; and graphical games, where the well-being of any particular player depends only on the actions of a small group other players. In ranking games, we further compare the payoffs obtainable in Nash equilibrium outcomes with those of alternative solution concepts that are easy to compute. We finally study, in general games, solution concepts that try to remedy some of the shortcomings associated with Nash equilibrium, like the need for randomization to achieve a stable outcome.
Endoscopic and histological characteristics of small bowel tumors diagnosed by double-balloon enteroscopy

Background/Aims Double-balloon enteroscopy (DBE) allows for the diagnoses and treatment of small bowel tumors (SBTs). This study aimed to evaluate the utility of DBE for the diagnosis and treatment of SBTs. Methods Patients diagnosed with SBTs who underwent DBE were included in this study. According to their endoscopic appearances, they were categorized as polyps or masses, and according to their histological characteristics, they were categorized as benign or malignant SBTs. Results A total of 704 patients were retrospectively analyzed, and 90 (12.8%) were diagnosed with SBTs. According to their endoscopic appearance, 48 (53.3%) had polyps and 42 (46.7%) had masses. Additionally, 53 (58.9%) and 37 (41.1%) patients had malignant and benign SBTs, respectively, depending on their histological characteristics. Patients diagnosed with polyps were younger than those diagnosed with masses (p<0.001). Patients diagnosed with benign SBTs were younger than those diagnosed with malignant SBT (p<0.001). Overall, histological diagnosis was determined using DBE in 73 (81.1%) patients. Conclusions DBE is a useful method for diagnosing SBTs. Additionally, the histological type of the lesion can be determined using DBE.
The Effects of Modified Atmosphere Packaging on the Quality Properties of Water Buffalo Milk’s Concentrated Cream

Concentrated cream (CC) is a dairy product containing more than 60% milk fat. CC has a very short shelf life because it is made from unripe cream. The present study aims to determine how packaging with reducing gas (H2) and nitrogen (N2) affects the quality properties and shelf life of CC. For this purpose, lipolysis, oxidation, color, microbiological, and free fatty acid development and the fatty acid composition of modified atmosphere packaged (MAP) CC samples were studied for 28 days. For MAP1, 96% N2 + 4% H2 was used, and for MAP2, 100% N2 and air was used for the control group. During storage, MAP1 samples remained at lower lipolysis (ADV and FFA) and oxidation levels than MAP2 and the control group. The MAP1 and MAP2 methods preserved the color of the samples and reduced the microbial growth rate. A lower formation of free fatty acids was observed in the samples packed with MAP1 and MAP2 than in the control group. The results showed that hydrogen gas positively affected the quality and storage time of samples.
The Analysis and Prediction of the 8–9 May 2007 Oklahoma Tornadic Mesoscale Convective System by Assimilating WSR-88D and CASA Radar Data Using 3DVAR

Abstract The Advanced Regional Prediction System (ARPS) model is employed to perform high-resolution numerical simulations of a mesoscale convective system and associated cyclonic line-end vortex (LEV) that spawned several tornadoes in central Oklahoma on 8–9 May 2007. The simulation uses a 1000 km × 1000 km domain with 2-km horizontal grid spacing. The ARPS three-dimensional variational data assimilation (3DVAR) is used to assimilate a variety of data types. All experiments assimilate routine surface and upper-air observations as well as wind profiler and Oklahoma Mesonet data over a 1-h assimilation window. A subset of experiments assimilates radar data. Cloud and hydrometeor fields as well as in-cloud temperature are adjusted based on radar reflectivity data through the ARPS complex cloud analysis procedure. Radar data are assimilated from the Weather Surveillance Radar-1988 Doppler (WSR-88D) network as well as from the Engineering Research Center for Collaborative and Adaptive Sensing of the Atmospher.
A Systematic Survey of H I Lyα and O VI Doublet Profiles Observed in Polar Coronal Holes at Solar Minimum

A systematic, comprehensive survey of H I Lyα and O VI doublet profiles in polar coronal holes is performed using spectroscopic observation by the SOHO Ultraviolet Coronagraph Spectrometer (UVCS) at solar minimum in 1996-1997. By decomposing coronal hole profiles into component Gaussians, we determine detailed height distributions of profile parameters for respective components. In particular, we show that for each of the O VI λλ103.2, 103.8 doublet lines, the narrow and broad components have competing intensities within heliocentric height 1.3-2.1 R☉, and that the considerable profile change occurring in this height range is due to changes not only of the widths of individual components but also of the mutual proportion between the narrow- and the broad-component intensities. We also show that the ratios between the O VI doublet intensities, Iλ 103.2/Iλ 103.8, for the narrow-narrow and the broad-broad component pairs have contrasting values and exhibit opposing radial dependences; the O VI ratio between the former pair increases with height from 2 at height 1 R☉ to 4 at 1.7 R☉, while that between the latter decreases with height from 2-3 at <1.8 R☉ to less than 1 at 2.5 R☉. We discuss implications of our results for the interpretation of the observed broad widths of the O VI doublet.