gebhart/patrepeval huggingface dataset:
How do the structure and the parameters of Gaussian tree models affect structure learning? (2009)

The problem of learning tree-structured Gaussian graphical models from i.i.d. samples is considered. The influence of the tree structure and the parameters of the Gaussian distribution on the learning rate as the number of samples increases is discussed. Specifically, the error exponent corresponding to the event that the estimated tree structure differs from the actual unknown tree structure of the distribution is analyzed. Finding the error exponent reduces to a least-squares problem in the very noisy learning regime. In this regime, it is shown that universally, the extremal tree structures which maximize and minimize the error exponent are the star and the Markov chain for any fixed set of correlation coefficients on the edges of the tree. In other words, the star and the chain graphs represent the hardest and the easiest structures to learn in the class of tree-structured Gaussian graphical models. This result can also be intuitively explained by correlation decay: pairs of nodes which are far apart, in terms of graph distance, are unlikely to be mistaken as edges by the maximum-likelihood estimator in the asymptotic regime.
Morphology and molecular dynamics of polyethylene by 1 H solid state NMR (2012)

A correlation study on the characterization of polyethylene was carried out between DSC and solid-state NMR. Both methods define the crystallinity of polyethylene precisely, and the benefit of solid-state NMR is its ability to describe the three-component phase composition based on the different molecular dynamics. The results provided by NMR-MOUSE are highly in agreement with those determined by DSC or high-field NMR in a wide crystallinity range. Besides, with the advantages of an open senor, nondestructive investigation on polyethylene pipes was carried out by NMR-MOUSE which has potential applications in the quality control of plastic pipe productions. Aging of polyethylene pipes due to the hydrostatic pressure and elevated temperature was investigated by spin-diffusion NMR. Morphological and molecular dynamical changes induced by physical aging were observed. Depending on the fracture types, the changes behave differently which are in turn decided by the applied pressures as well as the failure stages. The fundamental phenomenon of pipe aging is the embrittlement of molecular chains in the amorphous phase which, subsequently, reduces the mechanical resistance of the material against slow crack growth. Therefore, as a consequence, the long term performance of the pipes deteriorates. The current study also indicates that PE100 is an excellent candidate for piping solutions which is able to meet a wide range of end-user specifications. Morphological and molecular dynamical changes of polyethylene due to the presence of carbon nanotubes were investigated by 1H high-field NMR. The crystallinity and lamella thickness of polyethylene decreases with increasing amount of nanotubes. This is induced by a chain confinement effect which influences the crystallization kinetics of polyethylene when cooling from the melt. The change of residual dipolar coupling determined by the modified phase selectable double-quantum pulse sequence indicates that interactions between polymer matrix and nanotubes influence the amorphous phase most remarkably. They increase the chain restrictions and reduce the conformation diversities in this region. Both the above aspects influence the mechanical strength and the thermal stability of carbon nanotube polyethylene composite.
Exudate detection for diabetic retinopathy with convolutional neural networks (2017)

Exudate detection is an essential task for computer-aid diagnosis of diabetic retinopathy (DR), so as to monitor the progress of DR. In this paper, deep convolutional neural network (CNN) is adopted to achieve pixel-wise exudate identification. The CNN model is first trained with expert labeled exudates image patches and then saved as off-line classifier. In order to achieve pixel-level accuracy meanwhile reduce computational time, potential exudate candidate points are first extracted with morphological ultimate opening algorithm. Then the local region (64 × 64) surrounding the candidate points are forwarded to the trained CNN model for classification/identification. A pixel-wise accuracy of 91.92%, sensitivity of 88.85% and specificity of 96% is achieved with the proposed CNN architecture on the test database.
Learning to rank images using semantic and aesthetic labels (2012)

Most works on image retrieval from text queries have addressed the problem of retrieving semantically relevant images. However, the ability to assess the aesthetic quality of an image is an increasingly important differentiating factor for search engines. In this work, given a semantic query, we are interested in retrieving images which are semantically relevant and score highly in terms of aesthetics/visual quality. We use large-margin classifiers and rankers to learn statistical models capable of ordering images based on the aesthetic and semantic information. In particular, we compare two families of approaches: while the first one attempts to learn a single ranker which takes into account both semantic and aesthetic information, the second one learns separate semantic and aesthetic models. We carry out a quantitative and qualitative evaluation on a recentlypublished large-scale dataset and we show that the second family of techniques significantly outperforms the first one.
Influence of Si—OH groups on properties and avoidance for SiCOH films prepared by decamethylcyclopentasiloxane electron cyclotron resonance plasma (2006)

This paper investigates the effect of Si—OH groups on dielectric property and leakage current of the SiCOH low dielectric constant films deposited by decamethylcyclopentasioxane (D5) electron cyclotron resonance plasma. The results show that the increasing of Si—OH content in the films can lead to the increasing of dielectric constant k, decreasing of leakage current and rise in dielectric dispersion. The increasing of k value is the result of compensation of the decreasing of k value originated from cage by the strong polarization of Si—OH groups. The decreasing of leakage current at high Si—OH content is due to the low connecting probability p of networks because the networks break at the terminal Si—OH groups. In the case of high ionization degree of D5 plasma, more Si—OH groups break and form Si—O—Si linkages by chemical condensation occurring between proximal Si—OH groups. As a result, the k value of SiCOH films can be further reduced.
Photonic Microwave and RF Channelizers using CMOS Compatible Kerr Micro-combs (2021)

Abstract We report broadband RF channelizers based on integrated optical frequency Kerr micro-combs combined with passive micro-ring resonator filters, with microcombs having channel spacings of 200GHz and 49GHz. This approach to realizing RF channelizers offers reduced complexity, size, and potential cost for a wide range of applications to microwave signal detection.
First-order statistics of pulsed-sinusoid backscatter from random media: basic elements of an exact treatment (1997)

In ultrasonic imaging systems, the instantaneous pressure at the transducer face during echo reception is typically comprised of many superimposed reflections of a pulse resembling an amplitude-modulated sinusoid. Generally, these reflections are randomly shifted in phase and randomly scaled in amplitude. Moreover, each reflected pulse may have been distorted by passage through a nonuniform medium. The first-order amplitude statistics of such a waveform have long been considered of interest. The backscatter formation process has often been modeled as a random walk in two dimensions. For simplicity, the effects of amplitude-phase dependence and scatterer size distribution have not been fully included in previous work. In most cases of interest this is physically justified; but, given a strongly non-Rayleigh random medium, experience has shown that more accurate expressions may be required. This paper points to the essentials of such an improved analysis. The effects of pulse structure and scatterer size distribution on the statistical properties of the individual step of the random walk are considered de novo. Simulation results are described.
Impact of charged ionic species (NaCl and KCl) on the generation of color and volatile aroma compounds during caramelization (2022)

During the process of caramelization, volatile and non-volatile flavor and color are generated via the degradation of carbohydrates. This research investigated the effect of the types and concentrations of salts including NaCl and KCl on the generation of volatile aromas and color during caramelization. The solid phase microextraction-gas chromatograph-mass spectrometry (SPME-GC-MS) was used to measure the volatile compounds generated in caramelization. The results demonstrated that increasing content of salt (NaCl or KCl) could significantly improve (P<0.05) the generation of some essential volatile compounds during caramelization such as furfural, 5-methylfurfural, 5-hydroxymethyl-furfural (HMF), propionic acid and butyric acid. However, the ascending amount of salt (NaCl or KCl) had no significant impact (P<0.05) on the color generation of caramel. In conclusion, the usage of salt was beneficial to the generation of more aromatic compounds during caramelization.
Position-Specified Formation of Epitaxial Si Grains on Thermally Oxidized Si(001) Surfaces via Isolated Nanodots (2004)

We report position-specified fabrication of epitaxial Si grains on an amorphous thermal oxide layer on Si(001) substrates. This process takes advantage of unique features of surface-sensitive deposition chemistry and nanoscale oxidation phenomena. To make the grown grains epitaxial with respect to the Si substrate, growth was initiated from Si nanodots that had been isolated from the substrate by the oxidation of mushroom-shaped overgrown structures. The position of each grain is controlled by the use of a lithographically patterned mask layer. Mechanisms of the oxidation-induced nanodot isolation, which is a key step in this fabrication process, are discussed. The present technique is applicable to the integration of various single-crystal materials onto Si substrates.
Pseudocoloring encoding of depth information using Talbot effect (1980)

When an object is placed in the Fresnel diffraction field of a grating, the Talbot or self images of the grating delineate constant range contours on the object. If the image of the object with the superimposed Talbot images is bandpass filtered and normalized, an image is generated with bright regions corresponding to the range contours. If several such images are made with different illumination wavelengths so as to produce several contours, each filtered image can be assigned a different color to produce a pseudocolor display of depth information.
Modulation of antibody-mediated glomerular injury in vivo by bacterial lipopolysaccharide, tumor necrosis factor, and IL-1. (1989)

We have investigated the effects of LPS, human rTNF (hrTNF) and human rIL-1 beta (hrIL-1 beta) pretreatment on the intensity of antibody-mediated injury in vivo by using a passive model of anti-glomerular basement membrane (GBM) antibody-mediated nephritis in rats. The experiments show that all three pretreatments exacerbate injury in this model whether judged by albuminuria or the prevalence of glomerular capillary thrombi. The effect on albuminuria was dose dependent with all three treatments. The lowest effective dose of LPS was 0.025 microgram while those for hrTNF and hrIL-1 beta were 0.4 microgram and 0.5 microgram, respectively. All three pretreatments also increased the prevalence of glomerular capillary thrombi which were rare in rats injected with anti-GBM antibodies without pretreatment. LPS pretreatment appeared to be more effective in causing glomerular capillary thrombi than hrTNF or hrIL-1 beta and this was reflected in the correlations between albuminuria and the proportion of glomeruli with capillary thrombi. This relation was linear for all three pretreatments but the slope was appreciably greater for rats pretreated with LPS (0.37) when compared with results from rats given either hrTNF (0.22) or hrIL-1 beta (0.29). Pretreatment of nephritic rats with both cytokines increased the slope to 0.42 demonstrating a synergistic effect. The synergism of hrTNF with hrIL-1 beta was also demonstrated by the effective doses needed to induce albuminuria which was evident in rats treated with 0.05 microgram of IL-1 beta and 0.4 microgram of TNF. Neither the cytokines nor LPS caused clinical, morphologic, or biochemical evidence of renal toxicity when given alone in the dose used here but they did cause a transient increase in the number of neutrophils marginated in glomerular capillaries. Pretreatment of rats with LPS or cytokines increased the glomerular neutrophil influx after anti-GBM antibodies by roughly sixfold. Our experiments show that TNF and IL-1 can increase the severity of glomerular injury in nephritis; they may be important in modulating glomerular injury clinically.
Rectifying transport of a mixture of Brownian particles on an asymmetric periodic optical potential (2004)

Optical micro-manipulation has seen a resurgence of interest in recent years, which has been due in part to new application areas and the use of tailored forms of light beam. In this paper, experimental observations of fluctuation-driven transport of silica microspheres within a two-dimensional optical potential of circular symmetry are observed. The potential is created by a Bessel light beam. The optical field is tailored to break the symmetry and create a static tilted periodic (washboard) potential. Transitions between locked and running modes may be observed. The running mode manifests itself by rapid accumulation of particles at the beam centre. We discuss what happens with mixtures of particles in such an optical potential.
Performance Evaluation of Combined Photovoltaic Thermal Water Cooling System for Hot Climate Regions (2019)

Solar electric power generation utilizing photovoltaic (PV) modules is associated with low electrical efficiency that substantially decreases as its surface temperature exceeds an appropriate limit, particularly in hot climate regions. Consequently, it is required to keep PV modules relatively under a condition of low temperature using a cooling system as possible. The present experimental study evaluates the performance of the combined photovoltaic thermal (PV/T) module employing a water cooling system attached to the back surface during June for the city of Sohag in Egypt. The experimental results show that utilizing a water cooling system decreases the average surface temperature of the PV module from 44.8 °C to 30.3 °C on the back side and from 46.6 °C to 36.9 °C on the front side. The maximum value of the thermal heat gain of the PV/T module that is maintained at noon equals 230 W, and the corresponding value of the electrical power output is 34.4 W. Furthermore, the electrical efficiency of the PV/T module is 8% higher than that of the PV module without a water cooling system. Finally, the maximum and average values of the overall efficiency of PV/T module are 76.4% and 68.9%, respectively.
Design Method for a Low-Profile Dual-Shaped Reflector Antenna with an Elliptical Aperture by the Suppression of Undesired Scattering (2008)

A design method is proposed for a low-profile dual-shaped reflector antenna for the mobile satellite communications. The antenna is required to be low-profile because of mount restrictions. However, reduction of its height generally causes degradation of antenna performance. Firstly, an initial low-profile reflector antenna with an elliptical aperture is designed by using Geometrical Optics (GO) shaping. Then a Physical Optics (PO) shaping technique is applied to optimize the gain and sidelobes including mitigation of undesired scattering. The developed design method provides highly accurate design procedure for electrically small reflector antennas. Fabrication and measurement of a prototype antenna support the theory.
Biologic Adjuvants for Rotator Cuff Augmentation (2023)

Rotator cuff tears are a common injury in adults, and many patients will subsequently require surgical repair. While advancements in surgical technique have allowed for excellent time-zero mechanical repair of rotator cuff tears, retears remain a significant issue for patients and surgeons. Biologic adjuvants have been under investigation with the hope of reducing retears by enhancing the healing milieu following mechanical repair. Some of these adjuvants, which include platelet-rich plasma (PRP) products and pluripotent cell populations derived from bone marrow and subacromial bursa tissue can be harvested from the patient and administered intraoperatively. Our aim is to highlight the features of these adjuvants and review how they are implemented, including clinical outcomes when possible. Despite a significant amount of randomized controlled trials , inconsistent characterization of PRP products and lack of standardization regarding the production and implementation of PRP have led to heterogenous studies. Bone marrow aspirate concentrate and subacromial bursa tissue have shown the potential to enhance cellular regeneration but currently lack substantial clinical evidence. While standardization of methods may be impractical due to the numerous options for implementation, more consistent characterization of biologics may expedite progress toward consensus. Newer adjuvants in the setting of rotator cuff repair include exogenous pluripotent cells from human amnion , as well as bio-inductive scaffolds, and conditioned medium. As research on these burgeoning adjuvants grows, efforts to increase transparency through improved reporting and detailed methods may help to push this field forwards.
Development of an Atom Interferometer Gravity Gradiometer for Earth Sciences (2017)

We report progress towards a prototype atom interferometer gravity gradiometer for Earth science studies from a satellite in low Earth orbit.The terrestrial prototype has a target sensitivity of 8 x 10(exp -2) E/Hz(sup 1/2) and consists of two atom sources running simultaneous interferometers with interrogation time T = 300 ms and 12 hk photon recoils, separated by a baseline of 2 m. By employing Raman side band cooling and magnetic lensing, we will generate atomic ensembles with N = 10(exp 6) atoms at a temperature of 3 nK. The sensitivity extrapolates to 7 x 10(exp -5) E/Hz(sup 1/2) in microgravity on board a satellite. Simulations derived from this sensitivity demonstrate a monthly time-variable gravity accuracy of 1 cm equivalent water height at 200 km resolution, yielding an improvement over GRACE by 1-2 orders of magnitude. A gravity gradiometer with this sensitivity would also benefit future planetary, lunar, and asteroidal missions.
Electronic transport characteristics in a one-dimensional constriction defined by a triple-gate structure (2006)

We investigate the electronic transport characteristics of a one-dimensional (1D) narrow constriction defined in a GaAs∕AlxGa1−xAs heterostructure by a simple triple-gate structure consisting of a pair of split gates and an additional surface Schottky gate (center gate) between them. Comparison between devices with and without a center gate reveals that the center gate, even when zero biased (VCG=0V), significantly modifies the surface potential and facilitates the 1D confinement in a deep two-dimensional electron system. The pinch-off voltages at VCG=0V for various channel widths W (=0.4–0.8μm) and lengths L (=0.2–2μm) are well described by the analytical formula based on the pinned-surface model [J. H. Davies et al., J. Appl. Phys. 77, 4504 (1995)]. Nonlinear transport spectroscopy with an additional dc bias shows that the lowest 1D subband energy separation (ΔE1,2) changes linearly with VCG and can be enhanced by 70% for VCG=0.8V. A simple model assuming an infinitely long channel and no self-consistent potential well reproduces the overall behavior of the measured ΔE1,2. In addition, effects of impurities, occasionally found for long-channel devices (L⩾1μm), are found to be greatly reduced by applying positive VCG and thereby enhancing ΔE1,2. Data are also presented for the transport anomaly below the first conductance plateau, the so-called “0.7 anomaly,” demonstrating that the triple-gate structure is useful for the study of density-dependent phenomena in a 1D system.
Rotary motors sliding along surfaces (2009)

We introduce a family of molecular rotors that may convert light or chemical energy into directed translational motion along surfaces. The dependencies of diffusion coefficient and drift velocity of the rotating molecule on the magnitude of external torque, symmetry of surface potential, and temperature have been investigated. Our simulations show that the rotation-translation coupling could be very effective, and the molecule may move by approximately one surface lattice spacing per complete rotation. We have found that the unidirectionality of the rotary motion is not required to produce efficient directed sliding; this effect can be achieved by applying a time-periodic, or even randomly, oscillating torque which induces alternating molecular reorientations but does not generate complete rotations.
Methods for Estimating Parameters in the Mark-Houwink Equation from Measurement of Single Sample (1962)

Three methods are given for estimating the parameters Km and a in the so-called Mark-Houwink equationfrom measurement of single polymer-solvent system.The method 1; the parameters are calculated from intrinsic viscosity [η] and molecular weight M, the method 2; from [η], Mand second virial coefficient A2, the method 3; from A2 and M.These methods depend upon the theories which take account of the partly draining effect as well as the excluded volume effect.It is concluded that these methods are generally applicable for the practical purposes
Mental Fatigue Measurement Based on the Changes in Flicker Perception Threshold using Consumer Mobile Devices (2013)

We developed a technique to evaluate mental fatigue quantitatively by measuring perceptual performance of visually presented flicker;namely, the flicker-perception threshold (FPT), on consumer devices. Frequency domain flicker-perception threshold (FD-FPT) or critical fusion frequency (CFF), defined as a frequency at which intermittency of light disappears into a steady state for a human observer, is known to decrease as mental fatigue increases. Although FD-FPT has a long history as a reliable index of mental fatigue in the laboratory setting, it requires a dedicated device to measure, which impedes the use of this method by the general public. Additionally, arbitrariness and subjectivity of subject responses in the conventional flicker test present a significant problem for robust measurements of mental fatigue in everyday situations. This issue is especially important under such conditions where there is no supervision for users on how to respond to the ongoing flicker stimuli. We developed (a) a new method to control the subjective flickering sensation by changing the contrast of the visual stimuli instead of changing the temporal frequency, and (b) a new paradigm in which forced-choice task performance is used to determine FPT to eliminate arbitrariness of subject responses. The proposed techniques were implemented as application software, which enables persons to measure mental fatigue quantitatively using consumer mobile devices such as smart phones and PCs.