cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Least-squares Solutions of Eighth-order Boundary Value Problems using the Theory of Functional Connections
Creators: name: Johnston, Hunter
name: Leake, Carl
name: Mortari, Daniele
Publisher: name: arXiv
Year: 2020
Subjects: subject: Numerical Analysis (math.NA)
subject: FOS: Mathematics
subject: 34K10, 34K28, 65D05, 65L10, 65L60

description: This paper shows how to obtain highly accurate solutions of eighth-order boundary-value problems of linear and nonlinear ordinary differential equations. The presented method is based on the Theory of Functional Connections, and is solved in two steps. First, the Theory of Functional Connections analytically embeds the differential equation constraints into a candidate function (called a $constrained \, expression$) that contains a function that the user is free to choose. This expression always satisfies the constraints, no matter what the free function is. Second, the free-function is expanded as a linear combination of orthogonal basis functions with unknown coefficients. The constrained expression (and its derivatives) are then substituted into the eighth-order differential equation, transforming the problem into an unconstrained optimization problem where the coefficients in the linear combination of orthogonal basis functions are the optimization parameters. These parameters are then found by linear/nonlinear least-squares. The solution obtained from this method is a highly accurate analytical approximation of the true solution. Comparisons with alternative methods appearing in literature validate the proposed approach.
description: 14 pages, 1 figure, 8 tables
Distributing excess cash : The role of specially designated dividends
Creators: name: Baker, H
name: Mukherjee, Tarun K.
name: Powell, Gary E.
Publisher: name: American University
Year: 2023

description: This study explores why firms distribute excess cash as specially designated dividends (SDDs) instead of using regular dividends or repurchasing shares. We survey top managers of NASDAQ, AMEX, and NYSE firms issuing at least one SDD between 1994 and 2001. The results show that firms tend to pay SDDs when they experience strong earnings and cash flows and want to increase at least temporarily the yield to shareholders. Having strong earnings and cash flows also provide an impetus for regular dividend increases, but paying regular dividends is part of a firm’s standard dividend policy. The primary motives for repurchasing shares are to take advantage of perceived market undervaluation of the firm’s shares and to improve performance measures, especially. Overall, the results lend support to the signaling explanation for the disbursement of excess funds, but not the free cash flow or wealth transfer explanations.
VENOUS GANGRENE: REMINDING A VASCULAR CATASTROPHE
Creators: name: Novais Lima, Pedro
name: Cruz Silva, Joana
name: Gonçalves, Anabela
name: Fonseca, Manuel
Publisher: name: Portuguese Journal of Cardiac Thoracic and Vascular Surgery
Year: 2022

description: A 85 year-old, female patient, with an active colon neoplasm, was diagnosed with extensive ilio-femoro-popliteal deep vein thrombosis. She presented with severe oedema of the left lower limb and a cyanotic foot. Pedal pulses were palpable. Despite immediate anticoagulation, the patient expired at 72h.
description: Portuguese Journal of Cardiac Thoracic and Vascular Surgery, Vol. 28 No. 4 (2021): October - December
Self-Explanatory Information on COVID-19 (SARS-CoV-2)
Creators: name: Surendra Neupane
Publisher: name: figshare
Year: 2020
Subjects: subject: 111706 Epidemiology
subject: FOS: Health sciences
subject: Health Care

description: Self-Explanatory Information on COVID-19 (SARS-CoV-2)
The minimal of geometric deformation of Yang-Mills-Dirac stellar configurations
Creators: name: da Rocha, Roldao
Publisher: name: arXiv
Year: 2020
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: The method of minimal geometric deformation (MGD) is used to derive static, strongly gravitating, spherically symmetric, compact stellar distributions that are solutions of the Yang-Mills-Einstein-Dirac coupled field equations, on fluid membranes with finite tension. Their solutions characterize MGD Yang-Mills-Dirac stars, whose mass has order of the Chandrasekhar mass, once the range of both the fermionic self-interaction and the Yang-Mills coupling constants is suitably chosen. Physical features of MGD Yang-Mills-Dirac stars are then discussed, and their ADM mass are derived, as a function of the fermion coupling constant, the finite brane tension, and the Yang-Mills running parameter as well.
description: 9 pages, 5 figures
A research design and methodology for assessing the sustainability of the UBC Food System : indicators of sustainability of the UBC Food System
Creators: name: Allard, Ben
name: Gilliland, Alison
name: Hanacek, Blake
name: Kolb, Elliot
name: Miyazoe, Takeshi
name: Plaxton, Andrea
Publisher: name: The University of British Columbia
Year: 2014

description: While the University of British Columbia and its Campus Sustainability Office are at the forefront of sustainable development projects, they have yet to assess the sustainability of the UBC Food System. In this paper we map the current state of the UBC food system and present a continuum model of seven indicators of food system sustainability that we think adequately address the social, environmental and economic issues that arise in the development of a more sustainable food system. These seven indicators are the affordability of food, the presence of an effective consumer advocacy group, consumer satisfaction, the percentage of UBC Food Services and AMS Food and Beverage employees and management that are UBC students, the percentage of food waste composted and recycled, the percentage of locally-produced food entering the UBC food system, and a cost-benefit analysis of UBC Food Services and AMS Food Beverage. As these seven indicators overlap and conflict with one another, we stress that it is necessary for all indicators to be valued equally in order to move forward on the continuum from a stage of low sustainability to a stage of high sustainability. We propose a methodology that requires close communication between food providers, local suppliers, and consumers on campus. The implementation of the food system sustainability indicators needs to be carried out on a continuous basis over the next five years. It is therefore essential that one long-standing food system sustainability committee be established to work on this project. Disclaimer: “UBC SEEDS provides students with the opportunity to share the findings of their studies, as well as their opinions, conclusions and recommendations with the UBC community. The reader should bear in mind that this is a student project/report and is not an official document of UBC. Furthermore readers should bear in mind that these reports may not reflect the current status of activities at UBC. We urge you to contact the research persons mentioned in a report or the SEEDS Coordinator about the current status of the subject matter of a project/report.”
DESCENDING NECROTIZING MEDIASTINITIS - A MULTIDISCIPLINARY PATHOLOGY
Creators: name: Nicolau Fernandes, António
name: Santos, Ana Rita
name: Félix, Francisco
name: Luís, Leonel
Publisher: name: Portuguese Journal of Cardiac Thoracic and Vascular Surgery
Year: 2022

description: A 23-year-old man presented with fever and cervical swelling. Contrast-enhanced CT-scan with oblique sagittal planes reconstructions with extensive collection with gaseous areas, involving multiple cervical and mediastinal spaces is shown, reflecting a cervical-mediastinal necrotizing fasciitis. Note the circumference to the laryngotracheal axis. He underwent combined surgery by ENT and thoracic surgery and was discharged without sequelae after long hospitalization. This case demonstrates the importance of working in a multidisci- plinary team to treat complex pathologies.
description: Portuguese Journal of Cardiac Thoracic and Vascular Surgery, Vol. 28 No. 4 (2021): October - December
Distributing excess cash : The role of specially designated dividends
Creators: name: Baker, H
name: Mukherjee, Tarun K.
name: Powell, Gary E.
Publisher: name: American University (Washington, D.C.)
Year: 2023
Subjects: classificationCode: 35
subject: Commerce, management, tourism and services

description: This study explores why firms distribute excess cash as specially designated dividends (SDDs) instead of using regular dividends or repurchasing shares. We survey top managers of NASDAQ, AMEX, and NYSE firms issuing at least one SDD between 1994 and 2001. The results show that firms tend to pay SDDs when they experience strong earnings and cash flows and want to increase at least temporarily the yield to shareholders. Having strong earnings and cash flows also provide an impetus for regular dividend increases, but paying regular dividends is part of a firm’s standard dividend policy. The primary motives for repurchasing shares are to take advantage of perceived market undervaluation of the firm’s shares and to improve performance measures, especially. Overall, the results lend support to the signaling explanation for the disbursement of excess funds, but not the free cash flow or wealth transfer explanations.
THE MALIGNANCY OF A BENIGN TUMOR
Creators: name: L. Antunes, André
name: Prieto, David
name: Antunes, Pedro
Publisher: name: Portuguese Journal of Cardiac Thoracic and Vascular Surgery
Year: 2022

description: A 67-year-old man with fatigue and dyspnea, in NYHA class IV, was admitted to our hospital. His evaluation, physical examination, and other investigations were carried out. An atypical finding was found and he was referred for cardiac surgery.
description: Portuguese Journal of Cardiac Thoracic and Vascular Surgery, Vol. 28 No. 4 (2021): October - December
CORONARY ARTERIES - WHEN CALCIFICATION POPS UP
Creators: name: Monteiro, Joana Raquel
name: Salgueiro, Sónia
name: Pinhal, Fernanda
Publisher: name: Portuguese Journal of Cardiac Thoracic and Vascular Surgery
Year: 2022

description: An 84-year-old woman, with background history of atrial fibrillation, cerebral vascular disease, ischemic heart failure by coronary disease with several stent implantation, presented in the emergency room with syncope. The chest radiograph evidenced the coronary trajectory by their calcification.
description: Portuguese Journal of Cardiac Thoracic and Vascular Surgery, Vol. 28 No. 4 (2021): October - December
Low-lying spectrum for lattice Dirac operators with twisted mass
Creators: name: Gattringer, Christof
name: Solbrig, Stefan
Publisher: name: arXiv
Year: 2005
Subjects: subject: High Energy Physics - Lattice (hep-lat)
subject: FOS: Physical sciences

description: We analyze the low-lying spectrum and eigenmodes of lattice Dirac operators with a twisted mass term. The twist term expels the eigenvalues from a strip in the complex plane and all eigenmodes obtain a non-vanishing matrix element with gamma-5. For a twisted Ginsparg-Wilson operator the spectrum is located on two arcs in the complex plane. Modes due to non-trivial topological charge of the underlying gauge field have their eigenvalues at the edges of these arcs and obey a remnant index theorem. For configurations in the confined phase we find that the twist mainly affects the zero modes, while the bulk of the spectrum is essentially unchanged.
description: Contribution to Lattice 2005, 6 pages
Naked Singularities in Higher Dimensional Szekeres Space-time
Creators: name: Debnath, Ujjal
name: Chakraborty, Subenoy
Publisher: name: arXiv
Year: 2003
Subjects: subject: Mathematical Physics (math-ph)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: In this paper we study the quasi-spherical gravitational collapse of (n+2) dimensional Szekeres space-time. The nature of the central shell focusing singularity so formed is analyzed by studying both the radial null and time-like geodesic originated from it. We follow the approach of Barve et al to analyze the null geodesic and find naked singularity in different situations.
description: 11 Latex Pages, 4 figures, RevTex style
DUPLICITY OF THE FEMORAL VEIN AS A RISK FACTOR FOR DEEP VENOUS THROMBOSIS - DIAGNOSIS BY ULTRASONOGRAPHY
Creators: name: Campagnolo, Maria Thereza
name: De Queiroz Pereira Da Silva, André
name: Duarte, Márcio Luís
name: Ribeiro Dos Santos, Lucas
name: Alves Urzeda, Márcio
Publisher: name: Portuguese Journal of Cardiac Thoracic and Vascular Surgery
Year: 2022

description: Femoral vein duplication is an anatomical abnormality with high prevalence in general population. Its diagnosis is through imaging exams, with greater emphasis on Doppler ultrasonography. The identification is crucial because it masks the clinical symptoms of deep vein thrombosis. Besides being an important anatomical pathway and, while in duplicity, it can be used as a possible vascular substitute, therefore making the knowledge of the anatomical path and its variants essential. Ultrasonography has attractive advantages over other methods, collecting data from patients in physiological conditions with- out the need of contrast, or exposure to ionizing radiation, providing anatomical details of the venous system and anatomical variations. When thrombus is suspected in a duplicated segment, examination of the lower limb with anatomical variation should not be used to justify the presence of duplication in the contralateral limb.
description: Portuguese Journal of Cardiac Thoracic and Vascular Surgery, Vol. 28 No. 4 (2021): October - December
Atomic-scale perspective on the origin of attractive step interactions on Si(113)
Creators: name: Ciobanu, C. V.
name: Tambe, D. T.
name: Shenoy, V. B.
name: Wang, C. Z.
name: Ho, K. M.
Publisher: name: arXiv
Year: 2003
Subjects: subject: Condensed Matter (cond-mat)
subject: FOS: Physical sciences

description: Recent experiments have shown that steps on Si(113) surfaces self-organize into bunches due to a competition between long-range repulsive and short-range attractive interactions. Using empirical and tight-binding interatomic potentials, we investigate the physical origin of the short-range attraction, and report the formation and interaction energies of steps. We find that the short-range attraction between steps is due to the annihilation of force monopoles at their edges as they combine to form bunches. Our results for the strengths of the attractive interactions are consistent with the values determined from experimental studies on kinetics of faceting.
description: 4 pages, 3 figures, to appear in Phys. Rev B, Rapid Communications
PERCUTANEOUS MECHANICAL THROMBECTOMY IN PHLEGMASIA CERULEA DOLENS: CASE REPORT AND LITERATURE REVIEW
Creators: name: Vinha, André
name: Pimenta, Joana
name: Vasconcelos, João
name: Maia, Miguel
name: Vidoedo, José
name: Almeida Pinto, João
Publisher: name: Portuguese Journal of Cardiac Thoracic and Vascular Surgery
Year: 2022

description: Introduction: Phlegmasia cerulea dolens is a potentially life-threatening complication of deep venous thrombosis, causing marked swelling and sudden severe pain in the limb, associated with cyanosis, edema and compartment syndrome that together compromise arterial supply. There is no consensus on its treatment. Case Report: A 36-year-old woman, with a history of cosmetic surgery 8 days before admission (abdominal liposuction), was admitted to the emergency department with edema, cyanosis, severe pain, decreased temperature and tenderness of the left lower limb. At physical exam, no distal pulses on the left lower limb were found. Angio-CT was performed, showing occlusion of left femoral vein, external and common iliac veins. The patient started treatment with enoxaparin (80 mg, subcutaneous, bid) and percutaneous mechanical thrombectomy (PMT) of the left iliac vein sector was performed, followed by balloon angioplasty and stenting of the left iliac vein sector. It was also deployed a temporary filter in the inferior vena cava. Thrombophilic workup was negative. The patient presented thorough clinical remission after the procedure (Villalta score 0). Two years after surgery, the patient is asymptomatic, and the Doppler ultrasound is unremarkable concerning morphologic changes throughout the left iliac vein sector. Conclusion: The treatment of phlegmasia cerulea dolens is challenging due to its severity and poor prognosis. Minimally invasive procedures, such as PMT can be an alternative to open surgery. It can also avoid the use of thrombolytics in patients with relative / absolute contraindications to its use.
description: Portuguese Journal of Cardiac Thoracic and Vascular Surgery, Vol. 28 No. 4 (2021): October - December
How Norwegian managers view dividend policy
Creators: name: Baker, H
name: Mukherjee, Tarun K.
name: Paskelian, Ohannes George
Publisher: name: American University
Year: 2023

description: We report the results of a 2004 survey from managers of dividend-paying Norwegian firms listed on the Oslo Stock Exchange about their views on dividend policy. Specifically, we identify the most important factors in making dividend policy decisions and managers’ views about various dividend-related issues. The most important determinants of a firm’s dividend policy are the level of current and expected future earnings, stability of earnings, current degree of financial leverage, and liquidity constraints. No significant correlation exists between the overall rankings of factors influencing dividend policy between Norwegian and U.S. managers. Norwegian managers express mixed views about whether a firm’s dividend policy affects firm value. Respondents point to the possible role of dividend policy as a signaling mechanism. No support exists for the tax-preference explanation for paying dividends.
Machine-Learning-Based Diagnostics of EEG Pathology
Creators: name: Gemein, Lukas Alexander Wilhelm
name: Schirrmeister, Robin Tibor
name: Chrabąszcz, Patryk
name: Wilson, Daniel
name: Boedecker, Joschka
name: Schulze-Bonhage, Andreas
name: Hutter, Frank
name: Ball, Tonio
Publisher: name: arXiv
Year: 2020
Subjects: subject: Image and Video Processing (eess.IV)
subject: Machine Learning (cs.LG)
subject: Signal Processing (eess.SP)
subject: Machine Learning (stat.ML)
subject: FOS: Electrical engineering, electronic engineering, information engineering
subject: FOS: Computer and information sciences

description: Machine learning (ML) methods have the potential to automate clinical EEG analysis. They can be categorized into feature-based (with handcrafted features), and end-to-end approaches (with learned features). Previous studies on EEG pathology decoding have typically analyzed a limited number of features, decoders, or both. For a I) more elaborate feature-based EEG analysis, and II) in-depth comparisons of both approaches, here we first develop a comprehensive feature-based framework, and then compare this framework to state-of-the-art end-to-end methods. To this aim, we apply the proposed feature-based framework and deep neural networks including an EEG-optimized temporal convolutional network (TCN) to the task of pathological versus non-pathological EEG classification. For a robust comparison, we chose the Temple University Hospital (TUH) Abnormal EEG Corpus (v2.0.0), which contains approximately 3000 EEG recordings. The results demonstrate that the proposed feature-based decoding framework can achieve accuracies on the same level as state-of-the-art deep neural networks. We find accuracies across both approaches in an astonishingly narrow range from 81--86\%. Moreover, visualizations and analyses indicated that both approaches used similar aspects of the data, e.g., delta and theta band power at temporal electrode locations. We argue that the accuracies of current binary EEG pathology decoders could saturate near 90\% due to the imperfect inter-rater agreement of the clinical labels, and that such decoders are already clinically useful, such as in areas where clinical EEG experts are rare. We make the proposed feature-based framework available open source and thus offer a new tool for EEG machine learning research.
PLEURAL METASTASIS OF A PEDIATRIC OSTEOSARCOMA
Creators: name: Marinho, Ana Sofia
name: Barbosa-Sequeira, Joana
name: Carvalho, Catarina
name: Carvalho, Fátima
name: Paupério, Gonçalo
Publisher: name: Portuguese Journal of Cardiac Thoracic and Vascular Surgery
Year: 2022

description: Introduction: Osteosarcoma is the most common primary bone tumor in children and young adults. Although osteosarcoma is a tumor with a great metastatic potential, mainly to the lung; pleural metastasis in patients with osteosarcoma are rarely reported. We present a case of 16 years-old male with a pleural metastasis of a tibial osteosarcoma diagnosed 4years earlier. He was submitted to a left thoracotomy and intra-operatively a pleural mass and a left upper lobe lesion was identified. Video-assisted resection of the extra-pulmonary mass and a wedge resection of the left upper lobe lesion was performed. The surgery was uneventful. The patient is clinically well, asymptomatic, maintains active surveillance.
description: Portuguese Journal of Cardiac Thoracic and Vascular Surgery, Vol. 28 No. 4 (2021): October - December
How Norwegian managers view dividend policy
Creators: name: Baker, H
name: Mukherjee, Tarun K.
name: Paskelian, Ohannes George
Publisher: name: American University (Washington, D.C.)
Year: 2023
Subjects: classificationCode: 3502
subject: Banking, finance and investment
classificationCode: 4407
subject: Policy and administration

description: We report the results of a 2004 survey from managers of dividend-paying Norwegian firms listed on the Oslo Stock Exchange about their views on dividend policy. Specifically, we identify the most important factors in making dividend policy decisions and managers’ views about various dividend-related issues. The most important determinants of a firm’s dividend policy are the level of current and expected future earnings, stability of earnings, current degree of financial leverage, and liquidity constraints. No significant correlation exists between the overall rankings of factors influencing dividend policy between Norwegian and U.S. managers. Norwegian managers express mixed views about whether a firm’s dividend policy affects firm value. Respondents point to the possible role of dividend policy as a signaling mechanism. No support exists for the tax-preference explanation for paying dividends.
Direct measurement of molecular stiffness and damping in confined water layers
Creators: name: Jeffery, Steve
name: Hoffmann, Peter M.
name: Pethica, John B.
name: Ramanujan, Chandra
name: Özer, H. Özgür
name: Oral, Ahmet
Publisher: name: arXiv
Year: 2003
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We present {\em direct} and {\em linear} measurements of the normal stiffness and damping of a confined, few molecule thick water layer. The measurements were obtained by use of a small amplitude (0.36 $\textrmÅ$), off-resonance Atomic Force Microscopy (AFM) technique. We measured stiffness and damping oscillations revealing up to 7 layers separated by 2.56 $\pm$ 0.20 $\textrmÅ$. Relaxation times could also be calculated and were found to indicate a significant slow-down of the dynamics of the system as the confining separation was reduced. We found that the dynamics of the system is determined not only by the interfacial pressure, but more significantly by solvation effects which depend on the exact separation of tip and surface. Thus ` solidification\rq seems to not be merely a result of pressure and confinement, but depends strongly on how commensurate the confining cavity is with the molecule size. We were able to model the results by starting from the simple assumption that the relaxation time depends linearly on the film stiffness.
description: 7 pages, 6 figures, will be submitted to PRB
Aliphatic hydrocarbon content of the interstellar dust
Creators: name: Günay, B.
name: Schmidt, T. W.
name: Burton, M. G.
name: Afşar, M.
name: Krechkivska, O.
name: Nauta, K.
name: Kable, S. H.
name: Rawal, A.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: In the interstellar medium, carbon is distributed between the gas and solid phases. However, while about half of the expected carbon abundance can be accounted for in the gas phase, there is considerable uncertainty as to the amount incorporated in interstellar dust. The aliphatic component of the carbonaceous dust is of particular interest because it produces a significant 3.4 $μ$m absorption feature when viewed against a background radiation source. The optical depth of the 3.4 $μ$m absorption feature is related to the number of aliphatic carbon C-H bonds along the line of sight. It is possible to estimate the column density of carbon locked up in the aliphatic hydrocarbon component of interstellar dust from quantitative analysis of the 3.4 $μ$m interstellar absorption feature providing that the absorption coefficient of aliphatic hydrocarbons incorporated in the interstellar dust is known. We generated laboratory analogues of interstellar dust by experimentally mimicking interstellar/circumstellar conditions. The resultant spectra of these dust analogues closely match those from astronomical observations. The measurements of the absorption coefficient of aliphatic hydrocarbons incorporated in the analogues were carried out by a procedure which combined FTIR and $^{13}$C NMR spectroscopies. The absorption coefficients obtained for both interstellar analogues were found to be in close agreement (4.76(8) $\times$ 10$^{-18}$ cm group$^{-1}$ and 4.69(14) $\times$ 10$^{-18}$ cm group$^{-1}$), less than half those obtained in studies using small aliphatic molecules. The results thus obtained permit direct calibration of the astronomical observations, providing rigorous estimates of the amount of aliphatic carbon in the interstellar medium.
Impact of financial and multinational operations on manager perceptions of dividends
Creators: name: Baker, H
name: Dutta, Shantanu
name: Saadi, Samir
Publisher: name: American University
Year: 2023

description: We survey managers of firms listed on the Toronto Stock Exchange about their views on dividends. We find the perceptions of factors that influence dividend policy differ between managers of financial and non-financial firms. Industry classification also affects how managers view statements about the dividend pattern, dividend setting process, dividend policy and firm value, residual dividend theory, and explanations for paying dividends. However, we find weak, if any, multinational operations effect on manager perception of dividends. We conclude that researchers investigating dividends should partition the data by industry type and perhaps other firm characteristics to better understand the dividend puzzle.
Impact of financial and multinational operations on manager perceptions of dividends
Creators: name: Baker, H
name: Dutta, Shantanu
name: Saadi, Samir
Publisher: name: American University (Washington, D.C.)
Year: 2023
Subjects: classificationCode: 3502
subject: Banking, finance and investment

description: We survey managers of firms listed on the Toronto Stock Exchange about their views on dividends. We find the perceptions of factors that influence dividend policy differ between managers of financial and non-financial firms. Industry classification also affects how managers view statements about the dividend pattern, dividend setting process, dividend policy and firm value, residual dividend theory, and explanations for paying dividends. However, we find weak, if any, multinational operations effect on manager perception of dividends. We conclude that researchers investigating dividends should partition the data by industry type and perhaps other firm characteristics to better understand the dividend puzzle.
Boosting Monte Carlo simulations of spin glasses using autoregressive neural networks
Creators: name: McNaughton, B.
name: Milošević, M. V.
name: Perali, A.
name: Pilati, S.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Computational Physics (physics.comp-ph)
subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: The autoregressive neural networks are emerging as a powerful computational tool to solve relevant problems in classical and quantum mechanics. One of their appealing functionalities is that, after they have learned a probability distribution from a dataset, they allow exact and efficient sampling of typical system configurations. Here we employ a neural autoregressive distribution estimator (NADE) to boost Markov chain Monte Carlo (MCMC) simulations of a paradigmatic classical model of spin-glass theory, namely the two-dimensional Edwards-Anderson Hamiltonian. We show that a NADE can be trained to accurately mimic the Boltzmann distribution using unsupervised learning from system configurations generated using standard MCMC algorithms. The trained NADE is then employed as smart proposal distribution for the Metropolis-Hastings algorithm. This allows us to perform efficient MCMC simulations, which provide unbiased results even if the expectation value corresponding to the probability distribution learned by the NADE is not exact. Notably, we implement a sequential tempering procedure, whereby a NADE trained at a higher temperature is iteratively employed as proposal distribution in a MCMC simulation run at a slightly lower temperature. This allows one to efficiently simulate the spin-glass model even in the low-temperature regime, avoiding the divergent correlation times that plague MCMC simulations driven by local-update algorithms. Furthermore, we show that the NADE-driven simulations quickly sample ground-state configurations, paving the way to their future utilization to tackle binary optimization problems.
description: 13 pages, 14 figures
The new record holder for the most iron-poor star: HE 1327-2326, a dwarf or subgiant with [Fe/H]=-5.4
Creators: name: Frebel, A.
name: Aoki, W.
name: Christlieb, N.
name: Ando, H.
name: Asplund, M.
name: Barklem, P. S.
name: Beers, T. C.
name: Eriksson, K.
name: Fechner, C.
name: Fujimoto, M. Y.
name: Honda, S.
name: Kajino, T.
name: Minezaki, T.
name: Nomoto, K.
name: Norris, J. E.
name: Ryan, S. G.
name: Takada-Hidai, M.
name: Tsangarides, S.
name: Yoshii, Y.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We describe the discovery of HE 1327-2326, a dwarf or subgiant with [Fe/H]}=-5.4. The star was found in a sample of bright metal-poor stars selected from the Hamburg/ESO survey. Its abundance pattern is characterized by very high C and N abundances. The detection of Sr which is overabundant by a factor of 10 as compared to iron and the Sun, suggests that neutron-capture elements had already been produced in the very early Galaxy. A puzzling Li depletion is observed in this unevolved star which contradicts the value of the primordial Li derived from WMAP and other Li studies. Possible scenarios for the origin of the abundance pattern (Pop. II or Pop. III) are presented as well as an outlook on future observations.
description: 6 pages, 2 figures, contributed paper to appear in "From Lithium to Uranium: Elemental Tracers of Early Cosmic Evolution", IAU Symposium 228, V. Hill, P. Francois & F. Primas, eds
DOEGE-POTTER SYNDROME BY PLEURAL SOLITARY FIBROUS TUMOR
Creators: name: Alves, Ana Sofia
name: Antunes, Natalie
name: Santos, Joana
name: Reis, João Eurico
name: Calvinho, Paulo
Publisher: name: Portuguese Journal of Cardiac Thoracic and Vascular Surgery
Year: 2022

description: Introduction: Solitary fibrous tumor of the pleura (SFTP) is a rare neoplasm that accounts for less than 5% of all pleural tumors. We present the case of a 73-year-old man with a history of recurrent episodes of severe hypoglycemia secondary to a large malignant SFTP. This paraneoplastic manifestation of SFTP occurs in less than 5% of cases and is referred to as Doege-Potter syndrome. Although rare, this is an important and reversible cause of hypoglycemia, which is resolved by complete surgical resection of the tumor. We describe the pathogenesis, diagnosis, and treatment of Doege-Potter syndrome. Key imaging findings and pathologic correlation are shown.
description: Portuguese Journal of Cardiac Thoracic and Vascular Surgery, Vol. 28 No. 4 (2021): October - December
Hadron Blind Cherenkov Counters
Creators: name: Tserruya, I.
name: Aokia, K.
name: Woody, C.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Instrumentation and Detectors (physics.ins-det)
subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: In this paper, we present some of the most prominent realizations of the HBD concept in real experiments. We describe the first implementation of an HBD that was made in the CERES experiment at CERN using a spectrometer based on a doublet of hadron blind RICH detectors for the measurement of low-mass electron pairs in pA and AA collisions at the SPS. We next present a detailed account of a more extensive realization of the HBD that was made in the PHENIX experiment for the measurement of low-mass electron pairs in central heavy-ion collisions at RHIC, followed by a description of a very similar detector that is currently under construction at J-PARC for the measurement of vector mesons though their $e^+e^-$ decay in pA collisions. We conclude with a brief discussion of possible evolutions of the HBD concept as well as possible developments and uses of HBDs in experiments at the future Electron Ion Collider.
description: Contribution to the Special Issue of Nuclear Instruments and Methods in Physics Research, "A RICH Legacy"
Constraining Z' From Supersymmetry Breaking
Creators: name: Anoka, O. C.
name: Babu, K. S.
name: Gogoladze, I.
Publisher: name: arXiv
Year: 2004
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We suggest and analyze a class of supersymmetric Z' models based on the gauge symmetry U(1)_x = x Y - (B-L), where Y is the Standard Model hypercharge. For 1 < x < 2, the U(1)_x D-term generates positive contributions to the slepton masses, which is shown to solve the tachyonic slepton problem of anomaly mediated supersymmetry breaking (AMSB). The resulting models are very predictive, both in the SUSY breaking sector and in the Z' sector. We find M_Z' = (2-4) TeV and the Z-Z' mixing angle ξ= 0.001. Consistency with symmetry breaking and AMSB phenomenology renders the Z' "leptophobic", with Br(Z' -> e^+ e^-) = (1-1.6)% and Br(Z' -> q q-bar) = 44%. The lightest SUSY particle is either the neutral Wino or the sneutrino in these models.
description: 34 pages in LaTeX
Circulant Singular Spectrum Analysis: A new automated procedure for signal extraction
Creators: name: Bógalo, Juan
name: Poncela, Pilar
name: Senra, Eva
Publisher: name: arXiv
Year: 2020
Subjects: subject: Signal Processing (eess.SP)
subject: Applications (stat.AP)
subject: FOS: Electrical engineering, electronic engineering, information engineering
subject: FOS: Computer and information sciences

description: Sometimes, it is of interest to single out the fluctuations associated to a given frequency. We propose a new variant of SSA, Circulant SSA (CiSSA), that allows to extract the signal associated to any frequency specified beforehand. This is a novelty when compared with other procedures that need to identify ex-post the frequencies associated to extracted signals. We prove that CiSSA is asymptotically equivalent to these alternative procedures although with the advantage of avoiding the need of the subsequent frequency identification. We check its good performance and compare it to alternative SSA methods through several simulations for linear and nonlinear time series. We also prove its validity in the nonstationary case. To show how it works with real data, we apply CiSSA to extract the business cycle and deseasonalize the Industrial Production Index of six countries. Economists follow this indicator in order to assess the state of the economy in real time. We find that the estimated cycles match the dated recessions from the OECD showing its reliability for business cycle analysis. Finally, we analyze the strong separability of the estimated components. In particular, we check that the deseasonalized time series do not show any evidence of residual seasonality.
Assessing the sustainability of the University of British Columbia Food System
Creators: name: Au-Yeung, Mary
name: Coosemans, Johan
name: Hanna, Mike
name: Kung, Marisa
name: Nam, Ji Hee (Jessica)
name: Ramadan, Maysoon
name: Tronson, Jyoti
Publisher: name: The University of British Columbia
Year: 2014

description: The UBC community is made up of over thirty thousand people with an elaborate food system made up of four sub-systems. Each sub-system of the UBC Food System is made up of many components. In order to assess the sustainability of the UBC Food System, the UBC Food System was mapped, underlying value assumptions were defined, indicators were proposed, and a model was designed. Assessing the sustainability of the UBC Food System is complex and involves not only the sub-systems of the UBC Food System, but the Sustainability Office of UBC and the whole UBC community as well. Disclaimer: “UBC SEEDS provides students with the opportunity to share the findings of their studies, as well as their opinions, conclusions and recommendations with the UBC community. The reader should bear in mind that this is a student project/report and is not an official document of UBC. Furthermore readers should bear in mind that these reports may not reflect the current status of activities at UBC. We urge you to contact the research persons mentioned in a report or the SEEDS Coordinator about the current status of the subject matter of a project/report.”
THE USE OF NEAR INFRARED SPECTROSCOPY IN ALKAPTONURIA - THE MISLEADING OCHRONOSIS - A CASE REPORT AND LITERATURE REVIEW
Creators: name: Mateus, Carolina
name: Carvalho, Ana Filipa
name: Fonte Boa, Ana
Publisher: name: Portuguese Journal of Cardiac Thoracic and Vascular Surgery
Year: 2022

description: Introduction: Near infrared spectroscopy is a non-invasive method to assess regional oxygenation and is being used in transcatheter aortic valve implantation to document periods of cerebral hypoperfusion, where cerebrovascular events are one of the most feared complications. Alkaptonuria is a rare metabolic disease characterized by accumulation of homogentisic acid in tissues and body fluids. The accumulation of pigment might interfere with the absorption of near infrared light, used in near infrared spectroscopy monitoring. We present a case of near infrared spectroscopy failing to accurately monitor cerebral oximetry in a woman, with alkaptonuria, undergoing a transcatheter aortic valve implantation.
description: Portuguese Journal of Cardiac Thoracic and Vascular Surgery, Vol. 28 No. 4 (2021): October - December
title: Constraining the formation conditions of the ancient martian ALH 84001 carbonates
Creators: name: Tomkinson, Tim Oscar Roland
Publisher: name: The Open University
Year: 2013

description: The martian meteorite ALH 84001 contains carbonates that provide information about the past aqueous conditions on Mars 3.9 Ga, and have been suggested to display signatures of martian organics. Determining the conditions under which the carbonates formed is crucial for addressing whether there was once life on Mars and the history of martian hydrosphere and atmosphere. This study has combined new sample preparation techniques with fresh isotopic analyses of ALH 84001 carbonates and analogue materials, geochemical modelling and the testing of future equipment (WatSen) suitable for carbonate detection on Mars. The results from these lnvestigations have provided quantitative constraints on the formation environment for the ALH 84001 carbonates and an instrument capable of detecting carbonates on Mars. The microscale carbon and oxygen analyses of ALH 84001 carbonates provide the first combined transient study across the carbonates with δ13C and δ18O values correlated ,with chemical compositions. The δ13C values range from -18.6% to +23.2% extending and lowering the previous ion microprobe δ13C range found and suggests that reduced carbon is present in the carbonates. This component exists as either macromolecular carbon introduced through subsequent alteration, terrestrial contamination or martian organics. The δ18O range -0.1% +27.1% is consistent with previous authors and displays a clear correlation with δ18O enrichment with distance from the carbonates core to edge. An 18.6% range in δ18O values was measured across analogue carbonates similar in size, shape and chemical variation which formed in a hydrothermal environment
Individual and collective behavior of dust particles in a protoplanetary nebula
Creators: name: Garaud, P.
name: Barrière-Fouchet, L.
name: Lin, D. N. C.
Publisher: name: arXiv
Year: 2003
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We study the interaction between gas and dust particles in a protoplanetary disk, comparing analytical and numerical results. We first calculate analytically the trajectories of individual particles undergoing gas drag in the disk, in the asymptotic cases of very small particles (Epstein regime) and very large particles (Stokes regime). Using a Boltzmann averaging method, we then infer their collective behavior. We compare the results of this analytical formulation against numerical computations of a large number of particles. Using successive moments of the Boltzmann equation, we derive the equivalent fluid equations for the average motion of the particles; these are intrinsically different in the Epstein and Stokes regimes. We are also able to study analytically the temporal evolution of a collection of particles with a given initial size-distribution provided collisions are ignored.
description: 15 pages, 9 figures, submitted to ApJ
FLUORO-CT GUIDED BIOPSY OF LUNG NODULES: A STEP BY STEP REVISION
Creators: name: Vieites Branco, Inês
name: Martins, Sara
name: Monteiro, João Pedro
name: Rocha, Diogo
name: Pereira, Tiago
Publisher: name: Portuguese Journal of Cardiac Thoracic and Vascular Surgery
Year: 2022

description: Introduction: Transthoracic biopsies under fluoro-computer tomography (CT) guidance play an important role on the diagnosis and management of lung nodules, permitting histological examination and differentiation between benign and malignant lesions(1). Furthermore, with recent advances in target therapy, it is increasingly necessary to obtain tumor tissue for the analysis of molecular fingerprints allowing personalized treatment(1). Although many studies report low complication rates for this procedure, they are not negligible, urging the need for a structured and reproducible guide to reduce technique-related complications(1,2).
description: Portuguese Journal of Cardiac Thoracic and Vascular Surgery, Vol. 28 No. 4 (2021): October - December
Monte Carlo study of linear chain submonolayer structures.Application to Li/W(112)
Creators: name: Oleksy, Cz.
Publisher: name: arXiv
Year: 2003
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: The lattice gas model for adsorption of alkaline elements on W(112) surface is studied by Monte Carlo simulations. The model includes dipole--dipole interaction as well as long-range indirect interaction. The numerical results show that truncation of the indirect interaction even at 200$Å$ may change a phase diagram, i.e., new phases containing domain walls might occur. It is demonstrated that a defected phase can exist at high temperatures even if it is not stable at T=0. The phase diagram for Li/W(112) is constructed and long periodic chain structures (9*1), (6*1), (4*1), (3*1), and (2*1) are found to be stable at low temperatures. Role of thermal fluctuation is discussed by comparison of Monte Carlo results with mean field approximation results.
description: 7 pages, 7 figures, REVTeX
title: Differential effect of grassland mowing on arthropod taxa
Creators: name: Künast, Robert
name: Weisser, Wolfgang W.
name: Seibold, Sebastian
name: Mayr, David
name: Siegmüller, Nils
name: Schneider, Iris
name: Westenrieder, Martin
name: Blüthgen, Nico
name: Staab, Michael
name: Meyer, Sebastian T.
name: Achury, Rafael
Publisher: name: Wiley-Blackwell
Year: 2025

description: 1. Arthropods face a global decline attributed to habitat loss, climate change, pesticide use, and an intensification of land‐use practices such as mowing. Studies on the effects of mowing on arthropod abundance showed conflicting results potentially due to multiple factors, including study design, grassland management, sampling method, and arthropod taxon studied.
 
2. We conducted four studies in different grasslands, including intensively and extensively used agricultural and urban grasslands, utilising sweep netting, suction sampling, and pitfall traps. We compared the mowing responses of arthropod taxa between those studies at three different taxonomic resolutions (first‐level overall arthropods, second‐level orders, and third‐level families and suborders).
 
3. First, we discovered that mowing had a negative effect on overall arthropod abundance in all our studies (first level). Second, our four studies found that seven second‐ and third‐level taxa showed only negative, four only positive, and four mixed positive and negative responses. Third, regarding taxonomic resolution, no third‐level taxon reacted differently to mowing compared to the second‐level taxon it belongs to.
 
4. Our results indicate that for some taxa, mowing has a consistent negative (e.g. Diptera) or positive effects (e.g. Coleoptera). We suggest those groups have uniform phenological traits that make them especially vulnerable to mowing. For taxa showing mixed responses, we expect that study‐dependent factors such as region, sampling method, and grassland management affect their response to mowing.
Chiral effective model with the Polyakov loop
Creators: name: Fukushima, Kenji
Publisher: name: arXiv
Year: 2003
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We discuss how the simultaneous crossovers of deconfinement and chiral restoration can be realized. We propose a dynamical mechanism assuming that the effective potential gives a finite value of the chiral condensate if the Polyakov loop vanishes. Using a simple model, we demonstrate that our idea works well for small quark mass, though there should be further constraints to reach the perfect locking of two phenomena.
description: 6 pages, 6 figures; minor corrections (explanations brushed up)