cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
The disturbing "rise" of global income inequality
Creators: name: Sala-I-Martin, Xavier
Publisher: name: Columbia University
Year: 2002
Subjects: Economics

description: We use aggregate GDP data and within-country income shares for the period 1970-1998 to assign a level of income to each person in the world. We then estimate the gaussian kernel density function for the worldwide distribution of income. We compute world poverty rates by integrating the density function below the poverty lines. The $1/day poverty rate has fallen from 20% to 5% over the last twenty five years. The $2/day rate has fallen from 44% to 18%. There are between 300 and 500 million less poor people in 1998 than there were in the 70s. We estimate global income inequality using seven different popular indexes: the Gini coefficient, the variance of log-income, two of Atkinson's indexes, the Mean Logarithmic Deviation, the Theil index and the coefficient of variation. All indexes show a reduction in global income inequality between 1980 and 1998. We also find that most global disparities can be accounted for by across-country, not within-country, inequalities. Within-country disparities have increased slightly during the sample period, but not nearly enough to offset the substantial reduction in across-country disparities. The across-country reductions in inequality are driven mainly, but not fully, by the large growth rate of the incomes of the 1.2 billion Chinese citizens. Unless Africa starts growing in the near future, we project that income inequalities will start rising again. If Africa does not start growing, then China, India, the OECD and the rest of middle-income and rich countries diverge away from it, and global inequality will rise. Thus, the aggregate GDP growth of the African continent should be the priority of anyone concerned with increasing global income inequality.
Exploiting plaintiffs through settlement: Divide and conquer
Creators: name: Che, Yeon-Koo
name: Spier, Kathryn E.
Publisher: name: Columbia University
Year: 2007
Subjects: subject: Law
subject: FOS: Law

description: This paper considers settlement negotiations between a single defendant and N plaintiffs when there are fixed costs of litigation. When making simultaneous take-it-or-leave-it offers to the plaintiffs, the defendant adopts a divide and conquer strategy. Plaintiffs settle their claims for less than they are jointly worth. The problem is worse when N is larger, the offers are sequential, and the plaintiffs make offers instead. Although divide and conquer strategies dilute the defendant's incentives, they increase the settlement rate and reduce litigation spending. Plaintiffs can raise their joint payoff through transfer payments, voting rules, and covenants not to accept discriminatory offers.
Constraining Scale-Dependent Non-Gaussianity with Future Large-Scale Structure and the CMB
Creators: name: Becker, Adam
name: Huterer, Dragan
name: Kadota, Kenji
Publisher: name: arXiv
Year: 2012
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We forecast combined future constraints from the cosmic microwave background and large-scale structure on the models of primordial non-Gaussianity. We study the generalized local model of non-Gaussianity, where the parameter f_NL is promoted to a function of scale, and present the principal component analysis applicable to an arbitrary form of f_NL(k). We emphasize the complementarity between the CMB and LSS by using Planck, DES and BigBOSS surveys as examples, forecast constraints on the power-law f_NL(k) model, and introduce the figure of merit for measurements of scale-dependent non-Gaussianity.
description: 28 pages, 8 figures, 2 tables; v2: references updated
Coddling Fatalistic Criminals: A Dynamic Stochastic Analysis of Criminal Decision-Making
Creators: name: O'Flaherty, Brendan Andrew
Publisher: name: Columbia University
Year: 1997
Subjects: subject: Economics
subject: Criminology
subject: FOS: Law
subject: Criminal behavior
subject: Decision making

description: Decision makers who confront a long sequence of criminal opportunities act differently from those who confront a single opportunity. If the sequence is long enough, people will take big chances in return for very small gains, even if the provability of detection is very great and the scale of punishment very large. Risk neutral people will appear to love risk. For long enough sequences of future opportunities, raising the probability of detection increases the amount of crime committed, rather than lowering it. Constitutional safeguards are an important deterrent to crime.
Average Case ϵ-Complexity in Computer Science: A Bayesian View
Creators: name: Kadane, Joseph B.
name: Wasilkowski, Grzegorz W.
Publisher: name: Columbia University
Year: 1983
Subjects: subject: Computer science
subject: Mathematics
subject: FOS: Mathematics
subject: Bayesian statistical decision theory

description: Relations between average case ϵ-complexity and Bayesian statistics are discussed. An algorithm corresponds to a decision function, and the choice of information to the choice of an experiment. Adaptive information in ϵ-complexity theory corresponds to the concept of sequential experiment. Some results are reported, giving ϵ-complexity and minimax-Bayesian interpretations for factor analysis. Results from ϵ-complexity are used to establish that the optimal sequential design is no better than optimal nonsequential design for that problem.
Supersymmetry With Prejudice: Fitting the Wrong Model to LHC Data
Creators: name: Allanach, B. C.
name: Dolan, Matthew J.
Publisher: name: arXiv
Year: 2011
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: We critically examine interpretations of hypothetical supersymmetric LHC signals, fitting to alternative wrong models of supersymmetry breaking. The signals we consider are some of the most constraining on the sparticle spectrum: invariant mass distributions with edges and end-points from the golden cascade decay chain \tilde{q}_L -> q χ_2^0 (-> \tilde{l}^{\pm} l^{\mp} q) -> χ_1^0 l^+ l^- q. We assume a CMSSM point to be the `correct' one, and fit the signals instead to minimal gauge mediated supersymmetry breaking models (mGMSB) with a neutralino quasi-stable lightest supersymmetric particle, minimal anomaly mediation (mAMSB) and large volume string compactification models (LVS). mAMSB and LVS can be unambiguously discriminated against the CMSSM for the parameter point assumed and 1 inverse femtobarn of LHC data at 14 TeV. However, mGMSB would not be discriminated on the basis of the kinematic end-points alone, and would require further, more detailed investigation. The best-fit points of mGMSB and CMSSM look remarkably similar, making experimental discrimination at the LHC appear unlikely by any means.
description: 24 pages, 6 figures, v4: new discussion, clarification, 1 plot added
Frailty in older adults (≥50 years) living with Human Immunodeficiency Virus (HIV)
Creators: name: McMillan, Jacqueline Mary
Publisher: name: Cumming School of Medicine
Year: 2018
Subjects: subject: Older adult
subject: Frailty
subject: Human Immunodeficiency Virus
subject: HIV
subject: Geriatric Medicine
subject: Geriatrics
subject: Aging
subject: Education--Health
subject: Biophysics--Medical
subject: Health Sciences
subject: Health Care Management
subject: Psychology--Clinical

description: Antiretroviral therapy (ART) has increased the life expectancy of persons living with HIV/AIDS (PLWHA). Fifty percent of PLWHA are ≥ 50 years of age, and age-related comorbidities are an increasing concern. The prevalence of frailty in HIV is greater than in age-matched controls. We investigated a cohort of older (≥ 50 years) PLWHA at the Southern Alberta Clinic (SAC) in Calgary, Alberta, and screened for frailty. Patients were screened using three frailty measures: a Modified Frailty Phenotype, Clinical Frailty Scale and the Frailty Index. Patients identified as frail were offered a Comprehensive Geriatric Assessment performed by a Geriatrician and the results were shared with the HIV provider and the family physician. Over three hundred patients were screened using the MFP and CFS, and over 700 patients had a FI calculated. Frailty was associated with duration of ART, but not with known duration of HIV infection, CD4 cell count, viral load, or age.
Managing Homeless Shelters
Creators: name: O'Flaherty, Brendan Andrew
Publisher: name: Columbia University
Year: 2009
Subjects: Economics
Homelessness
Shelters for the homeless

description: This is a formal analysis of how homeless shelters should operate: in particular, what quality of accommodations they should provide and how they should help their residents in securing conventional housing. I also examine timing. The results extend to cover optimal police response to street homelessness as well. I draw heavily on the unemployment insurance literature.
The Economics of Repeated Extortion
Creators: name: Choi, Jay Pil
name: Thum, Marcel
Publisher: name: Columbia University
Year: 1998
Subjects: Economics

description: This paper provides a simple model of repeated extortion. In particular, we ask whether corrupt government officials' ex post opportunism to demand more once entrepreneurs have made sunk investments entails further distortion in resource allocations. We show that the inability of government officials to commit to future demands does not distort entry decisions any further if technology is not a choice variable for the entrepreneurs. The government official can properly discount the initial demand in order to induce the appropriate amount of entry. If, however, the choice of technology is left to the entrepreneurs, the dynamic path of demand schedules will induce entrepreneurs to pursue a "fly-by-night" strategy by adopting a technology with an inefficiently low sunk cost component. In this case, we show that the unique equilibrium is characterized by a mixed strategy of the government official on future demand. Our model thus explains why arbitrariness is such an inseparable feature of corruption. We also investigate implications of the stability of the corrupt regime for the dynamic extortion and discuss how our framework can be applied to other investment contexts involving the risk of expropriation.
Astronomical tuning, astronomical forcing and environmental conditions of the Lower Triassic Montney Formation, northeastern British Columbia, Canada
Creators: name: Shen, Chen
Publisher: name: Graduate Studies
Year: 2018
Subjects: subject: Geology
subject: FOS: Earth and related environmental sciences

description: Astronomical cyclicity calculated from a X-ray fluorescence (XRF) dataset from the biostratigraphically-constrained cyclic lithology of the distal Montney Formation at the c-65-F/94-B-8 core in northeastern British Columbia, generated a new astronomical time scale (ATS) for the entire Early Triassic. This ATS for the Lower Triassic Montney Formation provides dates for substages and stages (base-Dienerian at 251.1 Ma; base-Olenekian at 250.0 Ma; base-Spathian at 248.8 Ma; base-Anisian at 247.0 Ma) as well as an independent time calibration for the durations and rates of Early Triassic sedimentation and biotic recovery after the end-Permian mass extinction. This ATS compares closely with similar time-series analyses from South China demonstrating its potential for future global correlation. Moreover, two ecologically significant intervals (mid-late Dienerian and early Spathian), which show regular high frequency cyclicity in carbonate content, revealed a dominant obliquity signal that affected environmental and biotic changes. Lastly, this project has economic impact since the Montney Formation is a major natural gas play in Canada. A better understanding of environmental controls on cyclicity and of sedimentation rates will contribute to correlation and aspects of mechanical properties of the rocks.
Understanding β-Sheets in Alzheimer’s Disease to Confront it
Creators: name: Mehrazma, Banafsheh
Publisher: name: Graduate Studies
Year: 2018
Subjects: subject: Alzheimer's disease
subject: Molecular Dynamics
subject: Amyloid-β Peptide
subject: Structural Analysis
subject: Energy Analysis
subject: Biology--Molecular
subject: Biochemistry
subject: Chemistry--Pharmaceutical
subject: Chemistry--Physical

description: Based on the β-amyloid peptide (Aβ) hypothesis, Alzheimer’s disease develops when generation and clearance of Aβ become imbalanced. As a result, the peptide goes through structural changes, and establishes aggregates with high β-sheet content. In this thesis, the core hydrophobic region of the peptide, Aβ13-23, designated as “R”, is under investigation. The potency of a series of pseudo-peptides (PP) to block the aggregation of R, as a model of full-length Aβ42, are benchmarked by applying molecular dynamics (MD) and umbrella sampling calculations (MD-US). The effective binding free energy, ΔGeff, is used as a criterion to estimate the inhibitory ability of PPs. The all-L-amino acid PP, SGC1 and the all-D-amino acid SGB1 were predicted to have the highest anti-Aβ aggregation effect. The results are supported by experimental studies. The Electrospray ionization mass spectroscopy on R and one of PPs, named as SGA1, yielded a free energy of dissociation similar to MD-US. The PPs with the highest estimated inhibitory efficacy were further investigated against full-length Aβ42. All the PPs influence the overall structure of the monomeric Aβ. Two methods were exploited to examine the free energy of binding: i) a combination of GROMOS96 53a5 force field gas-phase energies and the Poisson-Boltzmann solvent accessible (PBSA) method, and ii) an improved linear interaction energy (LIE-D) technique. The ranking for PP-Aβ complexes for both methods were almost always consistent with MD-US results on PP-R complexes. The best PPs predicted to inhibit Aβ aggregation are the all-L amino acid inverso SGC1 and the all-D amino acids SGB1 and SGD1. Finally, the Aβ42 dimer conformations were investigated by a total of 9.5 μs MD simulations. The results from cluster analysis and energy calculations suggests that besides the Aβ13-23 (R) region, the C-terminal region of Aβ42 peptide plays an important role in β-sheet formation.
Essays on Distance Functions and Inefficiency Measurement
Creators: name: Esheba, Muna
Publisher: name: Arts
Year: 2018
Subjects: subject: Distance Functions
subject: Inefficiency Measurement
subject: Banking
subject: Economics
subject: Sociology--Theory and Methods

description: This dissertation includes three essays on distance functions and inefficiency measurement. The main focus of the three essays is the measurement and determinants of technical inefficiency theoretically and empirically. Essay 1 provides an up-to-date review that focuses on research methods, including different approaches to measuring technical inefficiency using distance functions, the development of modeling technical inefficiency, and the most common econometric estimation techniques. It also provides a useful guide on when these methods can be used and how to implement them. Regarding estimation issues, I address the important issues that should be managed in future applications while estimating technical inefficiency, including violation of theoretical and econometric regularity, the inaccurate choice of functional form, ignoring the possibility of heterogeneity and heteroskedasticity, and suffering from the endogeneity problem. I also discuss different approaches to deal with these issues, as well as potentially productive areas for future research. Essay 2 derives the interactive effect between input and output technical inefficiencies theoretically using directional distance functions. This derivation solves the arbitrary decomposition of overall technical inefficiency into input and output components in previous studies. I argue that overall technical inefficiency equals the sum of input and output technical inefficiencies plus an interactive effect component which captures the interactions between them. I prove the results theoretically using exogenous and endogenous directional vectors. Essay 3 investigates the relationships among input, output, and overall technical inefficiencies empirically using US banking data set. Using Bayesian estimation with the monotonicity conditions imposed at each observation, I estimate these inefficiencies separately using directional input, output, and technology distance functions. I model the overall technical inefficiency as a linear function of input and output technical inefficiencies, and a term capturing the interactions between them. These determinants of overall technical inefficiency are estimated simultaneously with the variables that determine the frontier. I find significant evidence of the interactive effect between input and output technical inefficiencies which has a negative effect on the overall technical inefficiency. This result is robust to alternative directional vectors and model specifications, suggesting that the adjustability of both inputs and outputs is required for the improvement of efficiency.
SOPHIE velocimetry of Kepler transit candidates. V. The three hot Jupiters KOI-135b, KOI-204b and KOI-203b (alias Kepler-17b)
Creators: name: Bonomo, A. S.
name: Hébrard, G.
name: Santerne, A.
name: Santos, N. C.
name: Deleuil, M.
name: Almenara, J.
name: Bouchy, F.
name: Díaz, R. F.
name: Moutou, C.
name: Vanhuysse, M.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: We report the discovery of two new transiting hot Jupiters, KOI-135b and KOI-204b, that were previously identified as planetary candidates by Borucki et al. 2011, and, independently of the Kepler team, confirm the planetary nature of Kepler-17b, recently announced by Desert et al. 2011. Radial-velocity measurements, taken with the SOPHIE spectrograph at the OHP, and Kepler photometry (Q1 and Q2 data) were used to derive the orbital, stellar and planetary parameters. KOI-135b and KOI-204b orbit their parent stars in 3.02 and 3.25 days, respectively. They have approximately the same radius, Rp=1.20+/-0.06 R_jup and 1.24+/-0.07 R_jup, but different masses Mp=3.23+/-0.19 M_jup and 1.02+/-0.07 M_jup. As a consequence, their bulk densities differ by a factor of four, rho_p=2.33+/-0.36 g.cm^-3 (KOI-135b) and 0.65+/-0.12 g.cm-3 (KOI-204b). Our SOPHIE spectra of Kepler-17b, used both to measure the radial-velocity variations and determine the atmospheric parameters of the host star, allow us to refine the characterisation of the planetary system. In particular we found the radial-velocity semi-amplitude and the stellar mass to be respectively slightly smaller and larger than Desert et al. These two quantities, however, compensate and lead to a planetary mass fully consistent with Desert et al.: our analysis gives Mp=2.47+/-0.10 M_jup and Rp=1.33+/-0.04 R_jup. We found evidence for a younger age of this planetary system, t<1.8 Gyr, which is supported by both evolutionary tracks and gyrochronology. Finally, we confirm the detection of the optical secondary eclipse and found also the brightness phase variation with the Q1 and Q2 Kepler data. The latter indicates a low redistribution of stellar heat to the night side (<16% at 1-sigma), if the optical planetary occultation comes entirely from thermal flux. The geometric albedo is A_g<0.12 (1-sigma).
description: submitted to Astronomy and Astrophysics
Theory of highly excited semiconductor nanostructures including Auger coupling: exciton-bi-exciton mixing in CdSe nanocrystals
Creators: name: Korkusinski, Marek
name: Voznyy, Oleksandr
name: Hawrylak, Pawel
Publisher: name: arXiv
Year: 2011
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We present a theory of highly excited interacting carriers confined in a semiconductor nanostructure, incorporating Auger coupling between excited states with different number of excitations. The Coulomb matrix elements connecting exciton, bi-exciton and tri-exciton complexes are derived and an intuitive picture of breaking neutral multi-exction complexes into positively and negatively charged multi-exciton complexes is given. The general approach is illustrated by analyzing the coupling of biexciton and exciton in CdSe spherical nanocrystals. The electron and hole states are computed using atomistic $sp^3d^5s^*$ tight binding Hamiltonian including an effective crystal field splitting and surface passivation. For each number of electron-hole pairs the many-body spectrum is computed in the configuration-interaction approach. The low-energy correlated biexciton levels are broken into charged complexes: a hole and a negatively charged trion and an electron and a positively charged trion. Out of a highly excited exciton spectrum a subspace coupled to bi-exciton levels via Auger processes is identified. The interaction between correlated bi-exciton and exciton states is treated using exact diagonalization techniques. This allows to extract the spectral function of the biexciton and relate its characteristic width and amplitude to the characteristic amplitude and timescale of the coherent time evolution of the coupled system. It is shown that this process can be described by the Fermi's Golden Rule only if a fast relaxation of the excitonic subsystem is accounted for.
description: 9 figures
Acoustic communication and vocal learning in belugas (Delphinapterus leucas)
Creators: name: Vergara, Valeria
Publisher: name: University of British Columbia
Year: 2011

description: Belugas (Delphinapterus leucas) are highly vocal cetaceans, but the function of their calls, repertoire ontogeny, and role of learning in vocal behavior are poorly understood. This dissertation examines these issues, focusing on a captive beluga group at the Vancouver Aquarium. First, I investigated vocal development in a beluga calf, longitudinally throughout his first year of life, and later opportunistically. The first sounds after birth were low energy, broadband pulse-trains, which increased in pulse repetition rate with age. He incorporated rudimentary whistles at two weeks. His mixed calls, which became consistent at four months, became progressively stereotyped, increasingly like his mother’s “Type-A” call, a presumed contact call. Six months after he was first exposed to his father’s calls, he developed a call type similar to one of his father’s. I discuss these findings in light of theories of sound production mechanisms, developmental stages of vocal acquisition, and vocal learning. Secondly, I examined context-specific use of call types recorded from the beluga group, with particular focus on the Type-A call. This signal constituted 24-97% of the vocalizations during isolation, births, deaths, presence of external stressors, and re-union of animals after separation. In contrast, it represented 4.4% of the vocalizations during regular sessions. I identified five Type-A variants subjectively and quantitatively. I used these findings to generate hypotheses about the usage of these signals by wild belugas, verified the existence of A-calls in the repertoire of St. Lawrence herds, and documented their usage by two wild individuals from different populations in contexts that supported their contact function. Finally, I investigated contextual vocal learning in trained tasks in adult belugas, focusing on the ability of a female beluga to respond to playbacks of two categories of beluga calls with matching vocalizations; pulse-trains are a natural category, and screams an artificial class shaped by training. The subject successfully matched only pulse-trains, the class that is part of this species’ natural repertoire. Her poor performance on matching screams might be partly explained by a difficulty to perceive categorically a signal that lacks a function in the natural repertoire of belugas.
An Almost Tight Lower Bound for Abortable Leader Election
Creators: name: Eghbali, Aryaz
Publisher: name: Graduate Studies
Year: 2018
Subjects: subject: Remote Memory Reference
subject: Distributed Algorithms
subject: Shared Memory
subject: Computer Science

description: This thesis introduces a general definition of abortability for object types with concurrent specifications. The main result discussed here is a lower bound of Ω(log n/ log log n) remote memory references (RMR) of abortable leader election in both cache coherent (CC) and distributed shared memory (DSM) models. Hence, showing a gap in the RMR complexity of abortable and non-abortable leader election, as leader election has O(1) RMR complexity [30]. Further, a small modification to the implementation of name-consensus and compare-and-swap [33] provides abortable name-consensus and abortable compare-and-swap in the CC model, given an abortable or atomic test-and-set object.
Dendrocoris reticulatus Barber 1911
Creators: name: Thomas, D. B. Jr.
name: H. Brailovsky
Publisher: name: Zenodo
Year: 1999
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hemiptera
Pentatomidae
Dendrocoris
Dendrocoris reticulatus

description: Dendrocoris reticulatus Barber 1911
Diagnosis. Vertex of head flat. Hemelytral membrane reticulate. Dorsal color uniformly tan, cicatrices concolorous with pronotal disk. Juga contiguous before tylus. Anterolateral pronotal margins subrectilinear in dorsal view, humeral angles prominent. Legs immaculate.Abdominal tubercle present in both sexes but smaller in males. Male pygophore with a pair of tiny black teeth on posterior aspect attending the medial emargination.
Distribution. USA: Arizona, Utah. MEXICO: Chihuahua.
Remarks. The reticulate venation is unique in the genus. The senior author has collected the species in numbers on oak trees in both countries.
description: Published as part of Thomas, D. B. Jr. & H. Brailovsky, 1999, Review of the genus Dendrocoris Bergroth with descriptions of new species (Pentatomidae: Heteroptera), pp. 1-9 in Insecta Mundi 13 on page 5
Design of Image Cryptosystem by Simultaneous VQ-Compression and Shuffling of Codebook and Index Matrix
Creators: name: Pal, Arup Kumar
name: Biswas, G. P.
name: Mukhopadhyay, S.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Cryptography and Security (cs.CR)
subject: FOS: Computer and information sciences

description: The popularity of Internet usage although increases exponentially, it is incapable of providing the security for exchange of confidential data between the users. As a result, several cryptosystems for encryption of data and images have been developed for secured transmission over Internet. In this work, a scheme for Image encryption/decryption based on Vector Quantization (VQ) has been proposed that concurrently encodes the images for compression and shuffles the codebook and the index matrix using pseudorandom sequences for encryption. The processing time of the proposed scheme is much less than the other cryptosystems, because it does not use any traditional cryptographic operations, and instead it performs swapping between the contents of the codebook with respect to a random sequence, which resulted an indirect shuffling of the contents of the index matrix. It may be noted that the security of the proposed cryptosystem depends on the generation and the exchange of the random sequences used. Since the generation of truly random sequences are not practically feasible, we simulate the proposed scheme using MATLAB, where its operators like rand(method, seed), randperm(n) has been used to generate pseudorandom sequences and it has been seen that the proposed cryptosystem shows the expected performance.
Higher Order Improvements for Approximate Estimators
Creators: name: Kristensen, Dennis
name: Salanie, Bernard
Publisher: name: Columbia University
Year: 2010
Subjects: Economics

description: Many modern estimation methods in econometrics approximate an objective function, through simulation or discretization for instance. The resulting "approximate" estimator is often biased; and it always incurs an efficiency loss. We here propose three methods to improve the properties of such approximate estimators at a low computational cost. The first two methods correct the objective function so as to remove the leading term of the bias due to the approximation. One variant provides an analytical bias adjustment, but it only works for estimators based on stochastic approximators, such as simulation-based estimators. Our second bias correction is based on ideas from the resampling literature; it eliminates the leading bias term for non-stochastic as well as stochastic approximators. Finally, we propose an iterative procedure where we use Newton-Raphson (NR) iterations based on a much finer degree of approximation. The NR step removes some or all of the additional bias and variance of the initial approximate estimator. A Monte Carlo simulation on the mixed logit model shows that noticeable improvements can be obtained rather cheaply.
Measurements of the Cosmic Ray Composition with Air Shower Experiments
Creators: name: Kampert, Karl-Heinz
name: Unger, Michael
Publisher: name: arXiv
Year: 2012
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: In this paper we review air shower data related to the mass composition of cosmic rays above 10$^{15}$ eV. After explaining the basic relations between air shower observables and the primary mass and energy of cosmic rays, we present different approaches and results of composition studies with surface detectors. Furthermore, we discuss measurements of the longitudinal development of air showers from non-imaging Cherenkov detectors and fluorescence telescopes. The interpretation of these experimental results in terms of primary mass is highly susceptible to the theoretical uncertainties of hadronic interactions in air showers. We nevertheless attempt to calculate the logarithmic mass from the data using different hadronic interaction models and to study its energy dependence from 10$^{15}$ to 10$^{20}$ eV.
description: 21 pages, invited review accepted for publication in Astroparticle Physics, Topical Issue on Cosmic Rays
Time-lapse rock physics inversion of thermal heavy oil production
Creators: name: Mutual, Evan Peter
Publisher: name: Graduate Studies
Year: 2018
Subjects: subject: Geophysics
subject: FOS: Earth and related environmental sciences
subject: Physics
subject: Applied Sciences

description: Time-lapse (4D) seismic monitoring of thermal heavy oil production represents a simple, robust and cost-effective method of characterizing changes in reservoir conditions. Conventional 4D seismic monitoring techniques track changes in a reservoir by comparing differences in seismic amplitudes and traveltimes over calendar time. These amplitude differences offer insight into the spatial extent of production and injection effects, but the physical cause of the observed amplitude differences is ambiguous. In order to properly distinguish between the effects of heated oil, steam, pressure, and temperature more information must be extracted from the seismic data. In this study, I combine AVO analysis and rock physics modeling in a rock physics inversion to quantify petrophysical changes in the reservoir thereby offering a more complete description of subsurface conditions during SAGD operations. With the resulting estimates for change in steam and heated oil saturations, the differentiation between varied fluid responses is possible. The heterogeneity of the SAGD operation is clearly observed. Areas surrounding the western well pairs with little to no steam or heated oil present contrast significantly with the large changes observed along the well pairs to the east. This leads to opportunities for improved production efficiency through the identification of zones with significant steam baffles and barriers, which significantly increase steam and energy requirement and prioritizing production of more efficient zones. Heated oil maps can also aid in identifying the most efficient zones and help track the mobilized bitumen to ensure it is not escaping or situated beyond the reach of the production wells. Together, results of this kind give operators valuable feedback that helps reduce both costs and environmental footprint for SAGD operations.
Quantum criticality in spin chains with non-ohmic dissipation
Creators: name: Sperstad, Iver Bakken
name: Stiansen, Einar B.
name: Sudbø, Asle
Publisher: name: arXiv
Year: 2012
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Other Condensed Matter (cond-mat.other)
subject: FOS: Physical sciences

description: We investigate the critical behavior of a spin chain coupled to bosonic baths characterized by a spectral density proportional to $ω^s$, with $s>1$. Varying $s$ changes the effective dimension $d_\text{eff} = d + z$ of the system, where $z$ is the dynamical critical exponent and the number of spatial dimensions $d$ is set to one. We consider two extreme cases of clock models, namely Ising-like and U(1)-symmetric ones, and find the critical exponents using Monte Carlo methods. The dynamical critical exponent and the anomalous scaling dimension $η$ are independent of the order parameter symmetry for all values of $s$. The dynamical critical exponent varies continuously from $z \approx 2$ for $s=1$ to $z=1$ for $s=2$, and the anomalous scaling dimension evolves correspondingly from $η\gtrsim 0$ to $η= 1/4$. The latter exponent values are readily understood from the effective dimensionality of the system being $d_\text{eff} \approx 3$ for $s=1$, while for $s=2$ the anomalous dimension takes the well-known exact value for the 2D Ising and XY models, since then $d_{\rm{eff}}=2$. A noteworthy feature is, however, that $z$ approaches unity and $η$ approaches 1/4 for values of $s < 2$, while naive scaling would predict the dissipation to become irrelevant for $s=2$. Instead, we find that $z=1,η=1/4$ for $s \approx 1.75$ for both Ising-like and U(1) order parameter symmetry. These results lead us to conjecture that for all site-dissipative $Z_q$ chains, these two exponents are related by the scaling relation $z = \text{max} {(2-η)/s, 1}$. We also connect our results to quantum criticality in nondissipative spin chains with long-range spatial interactions.
description: 8 pages, 6 figures
Legislative Alternatives to the Google Book Settlement
Creators: name: Samuelson, Pamela
Publisher: name: Columbia University
Year: 2011
Subjects: Copyright clearinghouses
Booksellers and bookselling--Colportage, subscription trade, etc.
Intellectual property

description: The audacity of the Google Book Search ("GBS") initiative, under which Google has scanned millions of in-copyright books from the collections of major research libraries in order to index their contents and serve up snippets in response to search queries, was surpassed only by the audacity of the proposed settlement of the class action lawsuit that challenged this scanning. Approval of the settlement would, among other things, have given Google the right to commercialize virtually every out-of-print book in the corpus (unless rights holders came forward to say no).
An MCMC approach to extracting the global 21-cm signal during the cosmic dawn from sky-averaged radio observations
Creators: name: Harker, Geraint J. A.
name: Pritchard, Jonathan R.
name: Burns, Jack O.
name: Bowman, Judd D.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: Efforts are being made to observe the 21-cm signal from the 'cosmic dawn' using sky-averaged observations with individual radio dipoles. In this paper, we develop a model of the observations accounting for the 21-cm signal, foregrounds, and several major instrumental effects. Given this model, we apply Markov Chain Monte Carlo techniques to demonstrate the ability of these instruments to separate the 21-cm signal from foregrounds and quantify their ability to constrain properties of the first galaxies. For concreteness, we investigate observations between 40 and 120 MHz with the proposed DARE mission in lunar orbit, showing its potential for science return.
description: 16 pages, 14 figures; accepted by MNRAS; minor edits to match accepted version
Some Nonlinear Operators Are as Easy to Approximate as the Identity Operator
Creators: name: Wasilkowski, Grzegorz W.
Publisher: name: Columbia University
Year: 1983
Subjects: subject: Computer science
subject: Mathematics
subject: FOS: Mathematics

description: In this paper we study the following problem. Given an operator S and a subset FO of some linear space, approximate S(f) for any f E FO possessing only partial information on f. Although all operators S considered here are nonlinear (e.g. minf(x), minlf(x), 1/f or lI f lI), we prove that these problems are "equivalent" to the problem of approximating S(f) = f, i.e., S = I. This equivalence provides optimal (or nearly optimal) information and algorithms.
Lattice Vibrational Modes and their Frequency Shifts in Semiconductor Nanowires
Creators: name: Yang, Li
name: Chou, M. Y.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Materials Science (cond-mat.mtrl-sci)
subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences

description: We have performed first-principles calculations to study the lattice vibrational modes and their Raman activities in silicon nanowires (SiNWs). Two types of characteristic vibrational modes are examined: high-frequency optical modes and low-frequency confined modes. Their frequencies have opposite size dependence with a red shift for the optical modes and a blue shift for the confined modes as the diameter of SiNWs decreases. In addition, our calculations show that these vibrational modes can be detected by Raman scattering measurements, providing an efficient way to estimate the size of SiNWs.
description: 12 pages, 5 figures
Information and Computation
Creators: name: Traub, Joseph F.
name: Wozniakowski, Henryk
Publisher: name: Columbia University
Year: 1983
Subjects: subject: Computer science
subject: Problem solving--Methodology
subject: Mathematics
subject: FOS: Mathematics
subject: Mathematics--Philosophy

description: Our work is based on two theses: (1) most problems are approximately solved; that is, we live with uncertainty; (2) for problems with partial or approximate information, the usual algorithm-centered approach can be supplemented, and sometimes replaced, by the information-centered approach. We briefly discuss these two theses here. Much of this article will be devoted to their expansion, illustrated by numerous examples.
Exercising the NON-VON Primary Processing Subsystem
Creators: name: Hillyer, Bruce K.
name: Shaw, David Elliot
Publisher: name: Columbia University
Year: 1983
Subjects: Computer science

description: The Primary Processing Subsystem of the NON-VON supercomputer potentially may comprise thousands of custom nMOS integrated circuits. It is vital that faulty components be detected and located. This paper provides a collection of algorithms to exercise the Primary Processing Subsystem so that the manifestation of latent faults may be observed.
Effects of fear factors in disease propagation
Creators: name: Wang, Yubo
name: Xiao, Gaoxi
name: Wong, Limsoon
name: Fu, Xiuju
name: Ma, Stefan
name: Cheng, Tee Hiang
Publisher: name: arXiv
Year: 2011
Subjects: subject: Physics and Society (physics.soc-ph)
subject: FOS: Physical sciences

description: Upon an outbreak of a dangerous infectious disease, people generally tend to reduce their contacts with others in fear of getting infected. Such typical actions apparently help slow down the spreading of infection. Thanks to today's broad public media coverage, the fear factor may even contribute to prevent an outbreak from happening. We are motivated to study such effects by adopting a complex network approach. Firstly we evaluate the simple case where connections between individuals are randomly removed due to fear factor. Then we consider a different case where each individual keeps at least a few connections after contact reduction. Such a case is arguably more realistic since people may choose to keep a few social contacts, e.g., with their family members and closest friends, at any cost. Finally a study is conducted on the case where connection removals are carried out dynamically while the infection is spreading out. Analytical and simulation results show that the fear factor may not easily prevent an epidemic outbreak from happening in scale-free networks. However, it significantly reduces the fraction of the nodes ever getting infected during the outbreak.
description: 19 pages, 10 figures
Fertility Intention and Family Planning Use among People Living with HIV/AIDS in Follow up Care Western Shoa Zone
Creators: name: Abebe, Mitsiwat
name: Endazenaw, Getabalew
Publisher: name: Journal of Science and Sustainable Development
Year: 2015

description: Human Immune Deficiency Virus (HIV) positive individuals may or may not have intention to have children. They could also have different degrees of utilization and demand for family planning. The desire of HIV infected persons to have children in the future has significant implication for the transmission of HIV to sexual partners or newborns. The study was designed to determine the fertility desire and contraceptive utilization among People Living with HIV in antiretroviral treatment (ART) follow up care in West Shoa Zone. An institution based cross sectional study design supplemented with qualitative in-depth interview was carried out between December 2011 and May 2012. The result showed that 78 (50.3%) male and 112 (36.5%) female respondents had expressed the desire for children, making a total of 190 (41.13%) of all the respondents. One hundred ninety-nine (43.1%) of the respondents were on family planning during the study period. Majority of the respondents 150(71.8%) were using condom. Respondents who showed desire for children were those who have no children, married and whose partners have desire to have children (P< 0.01). Those who were using family planning were educated (secondary and post secondary education), married, having three or more children and having knowledge on Mother To Child Transmission of HIV (P<0.05). The study also indicates that a number of women had no information on emergency contraceptive and had shown interest to use if unplanned sex has been practiced. Couples or individuals in need of children should be supported by availing adequate information on Prevention of Mother To Child Transmission service since high number of participants were in need of children
description: Journal of Science and Sustainable Development, Vol. 3 No. 1 (2015)
How to divide the possession of a football?
Creators: name: Che, Yeon-Koo
name: Hendershott, Terry
Publisher: name: Columbia University
Year: 2007
Subjects: Economics

description: In an National Football League overtime, a coin is tossed to determine which team will receive the kick off. In the sudden death format starting on offense has a significantly higher chance of winning. We examine two proposals to improve the ex post fairness: auctions and divide-and-choose. We find the auction to provide a better outcome than the divide-and-choose rule in general when the teams have asymmetric assessments about how the overtime game may unfold. The result has broad implications for resource division when individuals do not have complete information about the objects being divided.
MPEC 2025-F195 : 2025 FV11
Creators: name: Minor Planet Center Staff
Publisher: name: The Minor Planet Center
Year: 2025
Subjects: subject: Small Solar System bodies
valueUri: http://astrothesaurus.org/uat/1469
subject: 2025 FV11

description: The Minor Planet Electronic Circulars contain information on unusual minor planets, routine data on comets and natural satellites, and occasional editorial announcements.  They are published on behalf of Division F of the International Astronomical Union by the Minor Planet Center, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
Limit of three-point Green functions : the degenerate case
Creators: name: Thomas, Pascal J.
name: Hai, Duong Quang
Publisher: name: arXiv
Year: 2012
Subjects: subject: Complex Variables (math.CV)
subject: Algebraic Geometry (math.AG)
subject: FOS: Mathematics
subject: 32U35, 32A27

description: We investigate the limits of the ideals of holomorphic functions vanishing on three points in $\C^2$ when all three points tend to the origin, and what happens to the associated pluricomplex Green functions. This is a continuation of the work of Magnusson, Rashkovskii, Sigurdsson and Thomas, where those questions were settled in a generic case.
description: 15 pages
Revenue comparisons for auctions when bidders have arbitrary types
Creators: name: Che, Yeon-Koo
name: Gale, Ian
Publisher: name: Columbia University
Year: 2005
Subjects: Economics

description: This paper develops a methodology for characterizing expected revenue from auctions when bidders' types come from an arbitrary distribution. In particular, types may be multidimensional, and there may be mass points in the distribution. One application extends existing revenue equivalence results. Another application shows that first-price auctions yield higher expected revenue than second-price auctions when bidders are risk averse and face financial constraints. This revenue ranking extends to risk-averse bidders with general forms of non-expected utility preferences.
Demonstration of Jarzynski's Equality in Open Quantum Systems Using a Step-Wise Pulling Protocol
Creators: name: Ngo, Van A.
name: Haas, Stephan
Publisher: name: arXiv
Year: 2012
Subjects: subject: Quantum Physics (quant-ph)
subject: Chemical Physics (physics.chem-ph)
subject: Computational Physics (physics.comp-ph)
subject: Data Analysis, Statistics and Probability (physics.data-an)
subject: FOS: Physical sciences
subject: 82B03, 82B10, 82B30, 81Q93, 81-08

description: We present a generalization of Jarzynski's Equality, applicable to quantum systems, relating discretized mechanical work and free-energy changes. The theory is based on a step-wise pulling protocol. We find that work distribution functions can be constructed from fluctuations of a reaction coordinate along a reaction pathway in the step-wise pulling protocol. We also propose two sets of equations to determine the two possible optimal pathways that provide the most significant contributions to free-energy changes. We find that the transitions along these most optimal pathways, satisfying both sets of equations, follow the principle of detailed balance. We then test the theory by explicitly computing the free-energy changes for a one-dimensional quantum harmonic oscillator. This approach suggests a feasible way of measuring the fluctuations to experimentally test Jarzynski's Equality in many-body systems, such as Bose-Einstein condensates.
description: 9 pages, 5 figures