Miracle-dz/UniFAR-FTUs huggingface dataset:
Maximum Likelihood Estimation and Computation in a Random Effect Factor Model

Title of dissertation: MAXIMUM LIKELIHOOD ESTIMATION AND COMPUTATION IN A RANDOM EFFECT FACTOR MODEL Yang Cheng, Doctor of Philosophy, 2004 Dissertation directed by: Professor Eric V. Slud Department of Mathematics (STAT) We first briefly review some multivariate statistical models such as Principal Component Analysis (PCA), Factor Analysis (FA), and Probabilistic PCA (PPCA). Alternatively, we approach PCA from the least-squares point of view. We introduce a Random Effect Factor Model I (REFM1), which expresses the observed vectors up to random errors as a linear combination of a relatively small number of axis directions in a new coordinate system with random effect coefficients. Then, we characterize the maximum likelihood estimators (MLE) under REFM1 by a profile likelihood method, that is, by maximizing the likelihood over mean and variance parameters θ1 first with the coordinate direction parameters component θ2 fixed, we have a restricted MLE â, B̂, σ̂ in terms of the factor directions, and substituting the estimates θ̂1(θ2) into the likelihood, finally maximizing the profile likelihood over the factor directions θ2. We show that the maximizer of the profile likelihood function lp(θ2) over the factor directions combined with the restricted MLE for other parameters when the factor directions are fixed is the joint MLE of the likelihood function. Some asymptotic properties of the MLE such as consistency and asymptotic normal distribution are established. In order to analyze the multivariate data from s groups (s > 1), we briefly review the Common Principal Components (CPC) model. Other Random Effect Factor Models are introduced. The model REFM2 assumes all s groups have a common factor space but differing mean and variance parameters for factor loadings and error terms, and REFM3 is a new model which has not only a common factor space but also an additional individual space belonging to each group only. We discuss the identifiability of parameters, and again use the profile likelihood method to find the MLE. We develop an EM algorithm to compute the MLE for REFM1, and indicate extensions of the algorithm to REFM2 and REFM3. The performance of the algorithm on simulated data is described. Quasi-Newton methods are also used to calculate the MLE of the profile likelihood lp(θ2) and they yield the same results as the EM algorithm. Finally, we apply the EM algorithm for REFM1 estimation to a real data set on ultrasound cross-sectional images of the tongue during speech. MAXIMUM LIKELIHOOD ESTIMATION AND COMPUTATION IN A RANDOM EFFECT FACTOR MODEL
Magnetic moments of the low-lying 12 − octet baryon resonances

The magnetic moments of the negative-parity octet resonances with spin 12 : N ∗ (1535), N ∗ (1650), Σ ∗ (1620), and Ξ ∗ (1690) have been calculated within the framework of the chiral constituent quark model. In this approach, the presence of the polarized q ¯ q pairs (or the meson cloud, in other words) is considered by using the Lagrangian for Goldstone boson emission from the constituent quarks. Further, the explicit contributions coming from the spin and orbital angular momentum, including the eﬀects of the conﬁgurations mixing between the states with diﬀerent spins, are obtained. The motivation for these calculations comes from the recent interest in the experimental measurement of the magnetic moment of the S 11 (1535) resonance and of similar calculations being done within lattice quantum chromodynamics approaches. Our results can be compared with those expected to come from these sources.
Extended model of the electron in general relativity

A classical model of the spinning electron is proposed in which this particle is the source of the Kerr-Newman field. The electron is regarded as a charged rotating shell endowed with surface tension. It is the boundary where the exterior Kerr-Newman solution is matched to the interior flat spacetime metric. The shell is the surface of an oblate ellipsoid of revolution having a minor axis equal to the classical electron radius and a focal distance of the order of the corresponding Compton wavelength. This surface is undergoing rigid rotation with its equator at a velocity almost equal to the velocity of light. The arrangement of charges gives rise to a quadrupole electric moment, in addition to the magnetic dipole moment of the current distribution. The whole spacetime of this model is shown to be causally well behaved.
The effect of flood experience on public preferences for land preservation: evidence from referendum votes

In response to losses of open space, local open space referenda have become a popular means for land preservation in the U.S. This study is the first to empirically examine the relationship between flood experience and voter support for open space referenda. We collect data on open space referenda between 2001 to 2015 from the Trust for Public Land’s (TPL) LandVote database. Flood occurrence and damage data are derived from the Spatial Hazard Events and Losses Database for the United States (SHELDUS) database. Our findings suggest that voters become less supportive of subsequent open space ballot measures if their communities recently experienced a flood event. Our preferred specification indicates that a flood would decrease the odds of a ‘yes’ vote by about 7.5%. If we use flood damage data to measure disaster impacts, our results show that a 10% increase in flood damage is expected to decrease the odds of a ‘yes’ vote by about 6%. These findings are consistent with recent experimental research showing that disaster exposure has a negative effect on preferences for local public good investments.
Complexity of the Upper Solar Atmosphere Revealed from Spectropolarimetry during a Solar Eclipse

We analyze linear polarimetric spectrum data of solar emission lines with different formation temperatures in a visible light band from 516.3–532.6 nm, obtained during the 2013 Gabon solar eclipse using the prototype Fiber Arrayed Solar Optical Telescope. Complexities are found from the chromosphere through the transition zone to the corona at the spatial resolution limit of 2″ and temporal resolution of seconds. The observations show irregular spatial and spectral variations in linear polarization amplitudes, directions, and profile shapes. Within the observational band, spectral lines with different formation temperatures can have comparable polarization amplitudes in one spatial volume but one order difference in another, and at the same spatial volume, the amplitudes can differ by one order at different lines. The polarization amplitudes do not consistently increase with elongation in local regions. The variation in the direction of the polarization along the elongation is found from the green coronal line and the transition zone line more frequently than from the chromospheric lines. Such a variation in orientation is not synchronous for the different lines. Finally, Stokes Q/I profiles of the broad lines, such as the magnesium triplet and the green coronal line, show very diverse and complicated patterns. After pixel binning, we show that some of the complexity may be caused by the integration over different polarization sources at subresolution scales and/or along the line of sight in the optically thin layers with complex geometric corrugations.
Validation of the CFD-DPM solver DPMFoam in OpenFOAM (cid:2) through analytical, numerical and experimental comparisons

Multiphase ﬂows are relevant in several industrial processes mainly because they are present in the production of a large diversity of products. Hence, the availability of accurate numerical modeling tools, able to cope with this type of ﬂows, is of major signiﬁcance to provide detailed information about the system characteristics, in order to guide the design activity. This study presents a detailed assessment of a multiphase ﬂow solver able to couple Eulerian and Lagrangian phases, the last modeled through the discrete particle method. The numerical code is already implemented in the open source computational ﬂuid dynamics software package OpenFOAM (cid:2) . The solver ( DPMFoam ) is ﬁrstly used to simulate the collision between two particles, for which a good correlation was obtained with the theoretical impulse force value. Subsequently, the solver is employed in the simulation of a pseudo 2D gas-solid ﬂow in a ﬂuidized bed. In this case study, the results obtained for the bubble patterns, time-average ﬂow patterns, bed expansion dynamics and particle phase energy analysis are in agreement with the experimental and numerical results available in the literature. In addition, the numerical pressure drop for the ﬂuidized bed is computed and compared with the analytical Ergun’s pressure drop equation. The accuracy of the numerical results was found to be sensitive to the solid fraction estimation.
The Λ( 1405 ) resonance as a genuine three-quark or molecular state

The mechanism for the formation of the Λ( 1405 ) resonance is studied in a chiral quark model that includes quark-meson as well as contact (four point) interactions. The negative-parity S -wave scattering amplitudes for strangeness − 1 and 1 are calculated within a uniﬁed coupled-channel framework that includes the K N , ¯ K N , πΣ , ηΛ , K Ξ , πΛ , and ηΣ channels and possible genuine three-quark bare singlet and octet states corresponding to 12 − resonances. It is found that in order to reproduce the scattering amplitudes in the S 01 partial wave it is important to include the pertinent three-quark octet states as well as the singlet state, while the inclusion of the contact term is not mandatory. The Laurent-Pietarinen expansion is used to determine the S -matrix poles. Following their evolution as a function of increasing interaction strength, the mass of the singlet state is strongly reduced due to the attractive self-energy in the πΣ and ¯ K N channels; when it drops below the K N threshold, the state acquires a dominant ¯ K N component which can be identiﬁed with a molecular state. The attraction between the kaon and
EECS 182/282A Lecture 20: Pretraining and Fine-Tuning

Aside: For NLP, the byte pair encoding scheme is typically used for this step, which entails repeatedly grouping the most common occurring pair of characters together until the desired “token budget” is reached (similar to the grouping in Huffman encoding but in reverse). This process addresses the issue of encountering out-of-vocabulary words since they will just be broken down into common character sub-groups (read more here).
Optical bistability in mesoporous silicon microcavity resonators

We report on the observation of significant optical bistability in the transmission and reflection properties of mesoporous silicon microcavities when illuminated with a 150 ns pulsed laser at 532 nm. The observed optical hysteresis is shown to be transient in nature and the properties are strongly dependent on the porosity of the cavity layer. The onset and damage threshold intensity are also shown to be porosity dependent. Our modeling suggests that the observed effects are due to changes in the nonlinear refractive index where the transient lifetime increases with increasing porosity. We investigate the role of surface states on influencing the bistable process by passivating the internal porous surface with hydrosilylation chemistry.
Making a match: combining theory and evidence in policy-oriented macroeconomic modelling

A persistent question arising in the development of models for the analysis of macroeconomic policy has been the relative role of economic theory and evidence (data) in their construction. This paper looks at some strategies for transforming a Conceptual Model to become a Data-Adjusted Model, and how to adjust further to an Operational Model for policy analysis. Using a typical dynamic GE small open economy calibrated to UK data, we examine how some simple but formal econometric tests can be applied to test the match of the CM to the data. We also use the CM as a laboratory to assess model-building strategies. Our example suggests that, since one will never be sure that the choice of variables is appropriate, it is better to start with a CM and work towards making it match the data than attempting the converse
DIFFERENTIAL DIAGNOSIS BETWEEN BILIARY AND NONBILIARY ACUTE PANCREATITIS: WHAT IS THE IMPORTANCE OF LABORATORY TESTS?

ABSTRACT BACKGROUND: The differential diagnosis of the causal factors of acute pancreatitis is fundamental for its clinical follow-up, becoming relevant to establishing laboratory criteria that elucidate the difference between biliary and nonbiliary causes. AIM: The aim of this study was to establish criteria based on laboratory tests for the differential diagnosis between acute pancreatitis of biliary and nonbiliary causes and to identify laboratory tests with sufficient sensitivity to propose the creation of an algorithm for differential diagnosis between the causes. METHODS: The research consisted of observational analysis, with a cross-sectional design of laboratory tests of two groups of patients with acute pancreatitis: group A: nonbiliary cause and group B: biliary cause. Hematocrit, white blood cell count, lactate dehydrogenase, glucose, lipase, amylase, total bilirubin, oxalacetic transaminase, pyruvic transaminase, gamma-glutamyltransferase, and alkaline phosphatase were investigated. Data were submitted to nonparametric tests and receiver operating characteristics. RESULTS: Hematocrit values, number of leukocytes, lactate dehydrogenase, and glucose showed no significant difference between the groups (p>0.1). Lipase, amylase, total bilirubin, oxalacetic transaminase, pyruvic transaminase, gamma-glutamyltransferase, and alkaline phosphatase values showed a significant difference between groups (p<0.05). The oxalacetic transaminase, pyruvic transaminase, and alkaline phosphatase tests were most sensitive in determining the biliary cause, allowing the establishment of a cutoff point by the receiver operating characteristic test: pyruvic transaminase: 123.0 U/L (sensitivity: 69.2%; specificity: 81.5%), oxalacetic transaminase: 123.5 U/L (sensitivity: 57.3%; specificity: 78.8%), and alkaline phosphatase: 126.5 U/L (sensitivity: 66.1%; specificity: 69.4%), from which the probability of a correct answer increases. CONCLUSION: It was possible to establish criteria based on laboratory tests for the differential diagnosis between acute pancreatitis of biliary and nonbiliary origin; however, the tests did not show enough sensitivity to propose the creation of an algorithm for differential diagnosis between the same causes.
Multiscale modeling of sea clutter to facilitate detection of low observable targets within sea clutter

Sea clutter, the radar backscatter from the ocean surface, is highly complicated and non-stationary, due to multipath propagation of the radar returns and multiscale interactions at the air-sea interface. To facilitate robust detection of low observable targets within sea clutter, which is an important issue in coastal security, navigation safety and environmental monitoring, we propose a systematic multiscale approach to the modeling of sea clutter. Specifically, we (i) develop new methods to better fit non-stationary and non-Gaussian sea clutter, (ii) fully characterize the correlation structure of sea clutter on multiple time scales, (iii) develop a highly accurate cascade model for sea clutter, and (iv) develop accurate and readily implementable methods to detect low observable targets within sea clutter.
Esophagogastric Junction Outflow Obstruction and Hiatal Hernia: Is Hernia Repair Alone Sufficient?

Introduction: Esophagogastric junction outflow obstruction (EGJOO) is attributed to primary/idiopathic causes or secondary/mechanical causes, including hiatal hernias (HH). While patients with HH and EGJOO (HH+EGJOO) may undergo HH repair without myotomy, it is unclear if an underlying motility disorder is missed by therapy which addresses only the secondary EGJOO cause. The goal of this study was to determine if HH repair alone is sufficient management for HH+EGJOO patients. Methods: A retrospective review of patients who underwent HH repair between January 1, 2016 and January 31, 2020 was performed. Patients who underwent high-resolution esophageal manometry (HREM) within one year before HH repair were included. Patients with and without EGJOO on pre-operative HREM were compared. Results: Sixty-three patients were identified. Pre-operative HREM findings included: 43 (68.3%) normal, 13 (20.6%) EGJOO, 4 (6.3%) minor disorder or peristalsis, 2 (3.2%) achalasia, and 1 (1.6%) major disorder of peristalsis. No differences between patients with EGJOO or normal findings on pre-operative manometry were found in pre-operative demographics/risk factors, pre-operative symptoms, and pre-operative HREM, except higher integrated relaxation pressure in EGJOO patients. No differences were noted in length of stay, 30-day complications, long-term persistent symptoms, or recurrence with mean follow-up of 26-months. Of the 3 (23.1%) EGJOO patients with persistent symptoms, 2 underwent HREM demonstrating persistent EGJOO and none required endoscopic/surgical myotomy. Conclusion: Most HH+EGJOO patients experienced symptom resolution following HH repair alone and none required additional intervention to address a missed primary motility disorder. Further study is required to determine optimal management of patients with persistent EGJOO following HH repair.
A comparative investigator-initiated pilot study on the efficacy and safety of biodegradable microneedle acupuncture and conventional intradermal acupuncture for dry eye patient: A superiority, assessor-blinded, randomized controlled trial

Background: The prevalence of dry eye, which is a common lacrimal disease, is steadily increasing in modern society. However, fundamental treatment for it has not yet been established. This study aims to assess the efficacy and safety of a novel medical device, the biodegradable microneedle acupuncture (BMA), using a traditional intradermal acupuncture needle as the control acupuncture for dry eye. Method: This study will be an investigator-initiated, assessor-blinded, comparative, superiority pilot randomized controlled trial. A total of 30 patients with dry eye will be randomly assigned to the experimental or the control group in equal proportion. For the experimental group, the BMA will be applied to both sides of 5 acupoints including BL2, GB14, TE23, EX-HN5, and ST1. For the control group, conventional intradermal acupuncture will be applied to the same acupoints. The needles will be attached for 4 hours. Over 4 weeks, both the interventions will be performed 12 times in total. The primary outcome would be the ocular surface disease index. The secondary outcomes would be the visual analog scale for subjective symptoms, quality of life, Schirmer I test, and general assessment. Discussion: The findings of this study on the efficacy and safety of the BMA would be helpful for patients with dry eye in clinical practice. Further, these results would provide for the foundation of a large-scale BMA study.
Relationship between K-line distance and surgical outcome in cases of laminoplasty for cervical ossification of the posterior longitudinal ligament

Although previous studies indicate that changes in cervical alignment after laminoplasty and dynamic factors influence surgical outcomes of cervical ossification of the posterior longitudinal ligament (OPLL), the relationship between the surgical outcomes, the distance between the kyphosis-line (K-line) and OPLL, and dynamic factors have not yet been quantitatively evaluated. The purpose of the present study was to analyze the relationship between ΔK-line distance and surgical outcomes in cases of laminoplasty for OPLL of the cervical spine. We retrospectively reviewed 46 consecutive patients (33 men and 13 women) with cervical OPLL who underwent laminoplasty. “K-line distance” was measured as the minimum interval between the K-line and OPLL on lateral radiographs. The following factors were analyzed: K-line distance in neutral, flexion, and extension neck positions, ΔK-line distance, preoperative C2-7 range of motion (ROM), preoperative segmental ROM, preoperative C2-7 lordotic angle, occupying ratio of the OPLL, disease duration, preoperative and postoperative Japanese Orthopaedic Association (JOA) score, and recovery rate. Patients were divided into flexion K-line (+) and flexion K-line (−) groups. We then analyzed the influence of the K-line distance on surgical outcomes and conducted multivariate analysis to analyze the factors affecting surgical outcomes. The JOA score recovery rate in the flexion K-line (−) group was significantly lower than that in the flexion K-line (+) group (P = .024). The ΔK-line distance was significantly negatively correlated with the JOA score recovery rate (r = −0.531, P < .001). Additionally, multivariate analysis showed that ΔK-line distance (OR = −2.143, P = .015) was negatively correlated with the JOA score recovery rate. The ΔK-line distance is considered useful for the quantitative evaluation of dynamic factors and static compression factors due to OPLL through the measurement of dynamic radiographic images.
Layer-number-dependent work function of MoS2 nanoflakes

We investigated the layer-number-dependent work function of MoS2 nanoflakes by using Kelvin probe force microscopy (KPFM) to measure the surface potential. The work functions of as-prepared 1- to 6-layer MoS2 nanoflakes were 5.15–5.39 eV and increased with increasing layer number. After annealing, the work functions of the nanoflakes decreased to 0.1–0.2 eV due to elimination of absorbed molecules on the surface. However, the work function of the edge region of the annealed flakes was relatively larger than that of the internal region. The charge carrier trapping by adsorbed molecules due to the polarity and the hydrophilicity of MoS2 may cause a reduction in the work function of the annealed flakes compared with that for MoS2 exposed to air. The dependence of the obtained work function of MoS2 nanoflakes on the number of layers is essential to the formation of metal contacts for fabricating future MoS2-based devices.
Is “Trigonum sacrale” a real equilateral triangle? Anatomic consideration of sacral hiatus in adult: A three-dimensional CT study for reliable caudal access

This study is the first attempt to examine anatomical characteristics using three-dimensional computed tomography (3DCT) bone images with some parameters, in order to achieve correct and uncomplicated accesses. In addition, the study addresses a long-standing problem in the field and evaluates whether the trigonum sacrale forms an equilateral triangle or not. A detailed anatomic study of the sacral region was carried out on 91 patient 3DCT images. The CT data, in DICOM format, was read into VINCENT software from Fuji Film, with a slice thickness of 0.5 mm. The average length of sacral hiatus was 28.6 ± 8.4 (range 13.8–45.2 mm). The average width of sacral hiatus at the level of sacral cornua was 10.9 ± 2.7 (range 3.8–16.5 mm). The ratio between the length of the oblique and base line formed by the sacral triangle was 0.81 ± 0.12 (range 0.54–1.00). Using 3DCT images translated by the volume rendering technique, we can remove soft tissue from bones virtually. A slice thickness of 0.5 mm makes it a fine image, and permits meticulous measurement, which is different from previous cadaveric studies. Interestingly, our data showed that the ratio between oblique and base line on sacral triangle was <1.0, average 0.81. Findings demonstrated that the trigonum sacrale is not an equilateral triangle. This is useful information for the identification of the sacral hiatus when the landmark-based technique is employed.