Physical Sciences and Mathematics | Open Access Articles

The Effects Of Item Parceling On Goodness-Of-Fit And Parameter Estimate Bias In Structural Equation Modeling, Deborah L. Bandalos

Deborah L Bandalos

No abstract provided.

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Badanie Zmienności Wartości Wskaźników Roślinności Na Podstawie Zdjęć Satelitarnych, Przemysław Kupidura

Przemysław Kupidura

No abstract provided.

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Smoke And Mirrors Or Science? Teaching Law With Computers - A Reply To Cass Sunstein On Artificial Intelligence And Legal Science, Eric A. Engle

Eric A. Engle

The article explores the possibilities and limits of AI for teaching and modeling law.

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On The Approximation Properties Of Partial Sums Of Trigonometric Fourier Series, Ushangi Goginava

Ushangi Goginava

No abstract provided.

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On The Approximation Properties Of Cesàro Means Of Negative Order Of Walsh-Fourier Series, Ushangi Goginava

Ushangi Goginava

No abstract provided.

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Detection Of Iapetan Rifting (Rome Trough Tectonism) By Quaternary Karstification: Pulaski County, Kentucky, Lee J. Florea

Lee J Florea, PhD, P.G.

No abstract provided.

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The Importance Of The Normality Assumption In Large Public Health Data Sets, Paula Diehr, Thomas Lumley

Paula Diehr

It is widely but incorrectly believed that the t-test and linear regression are valid only for Normally distributed outcomes. The t-test and linear regression compare the mean of an outcome variable for different subjects. While these are valid even in very small samples if the outcome variable is Normally distributed, their major usefulness comes from the fact that in large samples they are valid for any distribution. We demonstrate this validity by simulation in extremely non-Normal data. We discuss situations in which in other methods such as the Wilcoxon rank sum test and ordinal logistic regression (proportional odds model) have …

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Weight-Modification Trials In Older Adults: What Should The Outcome Measure Be?, Paula Diehr

Paula Diehr

BACKGROUND: Overweight older adults are often counseled to lose weight, even though there is little evidence of excess mortality in that age group. Overweight and underweight may be more associated with health status than with mortality, but few clinical trials of any kind have been based on maximizing years of healthy life (YHL), as opposed to years of life (YOL). OBJECTIVE: This paper examines the relationship of body mass index (BMI) to both YHL and YOL. Results were used to determine whether clinical trials of weight-modification based on improving YHL would be more powerful than studies based on survival. DESIGN: …

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A Comparison Of Haloe V19 With Sage Ii V6.00 Ozone Observations Using Trajectory Mapping, Gary A. Morris, James F. Gleason, James M. Russell Iii, Mark R. Schoeberl, M. Patrick Mccormick

Gary A. Morris

We apply trajectory mapping to an 8-year intercomparison of ozone observations from the Halogen Occultation Experiment (HALOE) (V19) and Stratospheric Aerosol and Gas Experiment (SAGE) II (V6.00) for the months March, May, June, September, October, and December from the period December 1991 to October 1999. Our results, which represent the most extensive such intercomparison of these two data sets to date, suggest a root-mean-square difference between the two data sets of >15% below 22 km in the tropics and of 4–12% throughout most of the rest of the stratosphere. In addition, we find a bias with HALOE ozone low relative …

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Unemployment Scarring In High Unemployment Regions, Claudio Lupi, Patrizia Ordine

Claudio Lupi

This paper investigates the effect of individual unemployment experiences on re-employment wages. The empirical analysis is carried out on a panel of Italian individuals. The main result is that while in the northern regions the effect is similar to the one estimated for the UK, in the southern area of the country the impact is not significant. We link this result to the particular socio-economic environment in which the unemployment spells are experienced. We argue that this might be due to the fact that in a high unemployment environment individual unemployment experiences are perceived as "normal" and do not necessarily …

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Rockets And Feathers Revisited: An International Comparison On European Gasoline Markets, Marzio Galeotti, Alessandro Lanza, Matteo Manera

Matteo Manera

This paper re-examines the issue of asymmetries in the transmission of shocks to crude oil prices onto the retail price of gasoline. Relative to the previous literature, the distinguishing features of the present paper are: i) use of updated and comparable data to carry out an international comparison of gasoline markets; ii) two-stage modeling of the transmission of oil price shocks to gasoline prices (first refinery stage and second distribution stage), in order to assess possible asymmetries at either one or both stages; iii) use of asymmetric error correction models to distinguish between asymmetries that arise from short-run deviations in …

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Characterization Of Different Reactive Lysines In Bovine Heart Mitochondrial Porin. Al Jamal Ja, Philadelphia University

Philadelphia University, Jordan

No abstract provided.

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Learning From The President’S Council On Sustainable Development: The Need For A Real National Strategy, John C. Dernbach

John C. Dernbach

This is a review of United States sustainable development efforts at the national level from 1992-2002. At the United Nations Conference on Environment and Development in 1992, the United States and other countries agreed to develop and implement a national sustainable development strategy in order to fully integrate environmental matters into national decision making. In this period, the United States did not have such a strategy. Through much of the Clinton Administration, the President's Council on Sustainable Development (PCSD) (1993-1999) provided the basis for such a strategy through a rich variety of policy recommendations, but relatively little effort was made …

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Growing Correlation Length On Cooling Below The Onset Of Caging In A Simulated Glass-Forming Liquid, N. Lacevic, Francis W. Starr, T. B. Schrøder, V. N. Novikov, S. C. Glotzer

Francis Starr

No abstract provided.

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Molecular Dynamics Simulation Of A Polymer Melt With A Nanoscopic Particle, Francis W. Starr, T. B. Schroder, S. C. Glotzer

Francis Starr

No abstract provided.

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Transitions Between Inherent Structures In Water, Nicolas Giovambattista, Francis W. Starr, Francesco Sciortino, Sergey V. Buldyrev, H. Eugene Stanley

Francis Starr

No abstract provided.

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Regression Analysis Of Recurrent Gap Times With Time-Dependent Covariates, Ying Qing Chen, Mei-Cheng Wang, Yijian Huang

U.C. Berkeley Division of Biostatistics Working Paper Series

Individual subjects may experience recurrent events of same type over a relatively long period of time in a longitudinal study. Researchers are often interested in the distributional pattern of gaps between the successive recurrent events and their association with certain concomitant covariates as well. In this article, their probability structure is investigated in presence of censoring. According to the identified structure, we introduce the proportional reverse-time hazards models that allow arbitrary baseline function for every individual in the study, when the time-dependent covariates effect is of main interest. Appropriate inference procedures are proposed and studied to estimate the parameters of …

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Estimating Causal Parameters In Marginal Structural Models With Unmeasured Confounders Using Instrumental Variables, Tanya A. Henneman, Mark Johannes Van Der Laan, Alan E. Hubbard

U.C. Berkeley Division of Biostatistics Working Paper Series

For statisticians analyzing medical data, a significant problem in determining the causal effect of a treatment on a particular outcome of interest, is how to control for unmeasured confounders. Techniques using instrumental variables (IV) have been developed to estimate causal parameters in the presence of unmeasured confounders. In this paper we apply IV methods to both linear and non-linear marginal structural models. We study a specific class of generalized estimating equations that is appropriate to these data, and compare the performance of the resulting estimator to the standard IV method, a two-stage least squares procedure. Our results are applied to …

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Reactivity Profiles Of Ligands Of Mammalian Retinoic Acid Receptors: A Preliminary Corepa Analysis, Steven P. Bradbury, G. T. Ankley, O. G. Mekenyan, V. . Kamenska, P. K. Schmieder

Steven P. Bradbury

Retinoic acid and associated derivatives comprise a class of endogenous hormones that bind to and activate different families of retinoic acid receptors (RARs, RXRs), and control many aspects of vertebrate development. Identification of potential RAR and RXR ligands is of interest both from a pharmaceutical and toxicological perspective. The recently developed COREPA (COmmon REactivity PAttern) algorithm was used to establish reactivity profiles for a limited data set of retinoid receptor ligands in terms of activation of three RARs (a, b, g) and an RXR (a). Conformational analysis of a training set of retinoids and related analogues in terms of thermodynamic …

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Narrowing Historical Uncertainty: Probabilistic Classification Of Ambiguously Identified Tree Species In Historical Forest Survey Data, David J. Mladenoff, Sally E. Dahir, Eric V. Nordheim, Lisa A. Schulte, Glenn G. Guntenspergen

Lisa A. Schulte Moore

Historical data have increasingly become appreciated for insight into the past conditions of ecosystems. Uses of such data include assessing the extent of ecosystem change; deriving ecological baselines for management, restoration, and modeling; and assessing the importance of past conditions on the composition and function of current systems. One historical data set of this type is the Public Land Survey (PLS) of the United States General Land Office, which contains data on multiple tree species, sizes, and distances recorded at each survey point, located at half-mile (0.8-km) intervals on a 1-mi (1.6 km) grid. This survey method was begun in …

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Inclusive Gluon Production In Deep Inelastic Scattering At High Parton Density, Yuri V. Kovchegov, Kirill Tuchin

Kirill Tuchin

We calculate the cross section of single inclusive gluon production in deep inelastic scattering at very high energies in the saturation regime, where the parton densities inside hadrons and nuclei are large and the evolution of structure functions with energy is nonlinear. The expression we obtain for the inclusive gluon production cross section is generated by this nonlinear evolution. We analyze the rapidity distribution of the produced gluons as well as their transverse momentum spectrum given by the derived expression for the inclusive cross section. We propose an ansatz for the multiplicity distribution of gluons produced in nuclear collisions which …

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Three-Dimensional Landau Theory For Multivariant Stress-Induced Martensitic Phase Transformations. Ii. Multivariant Phase Transformations And Stress Space Analysis, Valery I. Levitas, Dean L. Preston

Valery I. Levitas

In this paper, the three-dimensional Landau model of austenite-martensite transformations constructed in Part I is generalized to include transformations between an arbitrary number of martensitic variants. The model can incorporate all temperature-dependent thermomechanical properties of both phases for arbitrary crystal symmetries, including higher-order elastic constants, and it correctly describes the characteristic features of stress-strain curves for shape-memory alloys and steels, namely, constant transformation strain tensors, constant or weakly temperature dependent stress hysteresis, and transformation at nonzero tangent moduli. Geometric representations of the conditions for phase equilibrium and phase transformations in six-dimensional stress space are developed. For the cubic-tetragonal phase transformation, …

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Three-Dimensional Landau Theory For Multivariant Stress-Induced Martensitic Phase Transformations. I. Austenite↔Martensite, Valery I. Levitas, Dean L. Preston

Valery I. Levitas

A three-dimensional Landau theory of stress-induced martensitic phase transformations is presented. It describes transformations between austenite and martensitic variants and transformations between martensitic variants. The Landau free energy incorporates all temperature-dependent thermomechanical properties of both phases. The theory accounts for the principal features of martensitic transformations in shape memory alloys and steels, namely, stress-strain curves with constant transformation strain and constant, or weakly temperature dependent, stress hysteresis, as well as nonzero tangent elastic moduli at the phase transformation point. In part I, the austenite↔martensite phase transformation is treated, while transformations between martensitic variants are considered in part II.

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Low-Cost Manufacturing Process For Nanostructured Metals And Alloys, Travis L. Brown, Srinivasan Swaminathan, Srinivasan Chandrasekar, W. Dale Compton, Alexander H. King, Kevin P. Trumble

Alexander H. King

In spite of their interesting properties, nanostructured materials have found limited uses because of the cost of preparation and the limited range of materials that can be synthesized. It has been shown that most of these limitations can be overcome by subjecting a material to large-scale deformation, as occurs during common machining operations. The chips produced during lathe machining of a variety of pure metals, steels, and other alloys are shown to be nanostructured with grain (crystal) sizes between 100 and 800 nm. The hardness of the chips is found to be significantly greater than that of the bulk material.

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Climate Change: National Interests Or A Global Regime?, Maria Ivanova, Christiana Figueres

Maria Ivanova

No abstract provided.

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Altitude Dependence Of Middleand Low-Latitude Thermospheric Disturbance Winds Measured By Windii, J. T. Emmert, Bela G. Fejer, G. G. Shepard, B. H. Solheim

Bela G. Fejer

[1] Thermospheric neutral winds exhibit strong altitudinal and latitudinal variation during geomagnetically quiet and active times. We use daytime middle and low-latitude neutral winds measured by the Wind Imaging Interferometer (WINDII) instrument on board the Upper Atmosphere Research Satellite (UARS) over the 90–275 km height range to study the altitude and season dependent climatology of disturbance winds (i.e., with quiet time patterns removed) in magnetic coordinates. The daytime perturbations winds are generally equatorward and westward and decrease toward the magnetic equator. Both the zonal and meridional components decrease sharply below 120 km and are essentially insignificant below 100 km. The …

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Ultra-Dense Phosphorous Delta-Layer Grown Into Silicon From Ph3 Molecular Precursors, T. -C. Shen, J. -Y. Ji, M. A. Zudov, R. -R. Du, J. S. Kline, J. R. Tucker

T. -C. Shen

Phosphorous δ-doping layers were fabricated in silicon by PH₃ deposition at room temperature, followed by low-temperature Si epitaxy.Scanning tunneling microscope images indicate large H coverage, and regions of c(2×2) structure. Hall data imply full carrier activation with mobility<40 cm²/V s when the surface coverage is ≲0.2 ML. Conductivity measurements show a ln(T) behavior at low temperatures, characteristic of a high-density two-dimensional conductor. Possible future applications to atom-scale electronics and quantum computation are briefly discussed.

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Star Formation In Bright Rimmed Clouds. I. Millimeter And Submillimeter Molecular Line Surveys, Christopher H. De Vries, Gopal Narayanan, Ronald L. Snell

Gopal Narayanan

We present the results of the first detailed millimeter and submillimeter molecular line survey of bright-rimmed clouds, observed at FCRAO in the CO (J = 1 ? 0), C18O (J = 1 ? 0), HCO+ (J = 1 ? 0), H13CO+ (J = 1 ? 0), and N2H+ (J = 1 ? 0) transitions, and at the Heinrich Hertz Telescope in the CO (J = 2 ? 1), HCO+ (J = 3 ? 2), HCO+ (J = 4 ? 3), H13CO+ (J = 3 ? 2), and H13CO+ (J = 4 ? 3) molecular line transitions. The source list is …

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Detection Of Infall Signatures Towards Serpens Smm4, Gopal Narayanan, G. Moriarty-Schieven, C.K. Walker, H.M. Butner

Gopal Narayanan

We present the detection of kinematic infall signatures toward the Class 0 protostellar system SMM4 in the Serpens cloud core. We have observed the dense molecular gas toward the embedded source using millimeter and submillimeter line transitions of density sensitive molecular tracers. High signal-to-noise ratio maps obtained in HCO+ J = 1 → 0, J = 3 → 2, and J = 4 → 3, and CS J = 2 → 1 show the blue-bulge infall signature. The blue-bulge infall signature can be observed in the centroid velocity maps of protostellar objects when infall dominates over rotation. The line profiles …

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Low Latitude Ice Cores Record Pacific Sea Surface Temperatures, Raymond S. Bradley, M. Vuille, D. R. Hardy, L. G. Thompson

Raymond S Bradley

Oxygen isotope variations in ice cores from Bolivia and Peru are highly correlated with sea surface temperatures (SSTs) across the equatorial Pacific Ocean, which are closely linked to ENSO variability. Circulation anomalies associated with this variability control moisture flux from the equatorial and tropical Atlantic Ocean and Amazon Basin to the ice core sites. Below average SSTs lead to higher accumulation rates and isotopically lighter snow; such conditions are also associated with lower atmospheric freezing levels. During warm events, opposite conditions prevail. Oxygen isotope variations in an ice core from the Himalayas also reflect SST variations in the equatorial Pacific …

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Full-Text Articles in Physical Sciences and Mathematics

The Effects Of Item Parceling On Goodness-Of-Fit And Parameter Estimate Bias In Structural Equation Modeling, Deborah L. Bandalos

Deborah L Bandalos

Badanie Zmienności Wartości Wskaźników Roślinności Na Podstawie Zdjęć Satelitarnych, Przemysław Kupidura

Przemysław Kupidura

Smoke And Mirrors Or Science? Teaching Law With Computers - A Reply To Cass Sunstein On Artificial Intelligence And Legal Science, Eric A. Engle

Eric A. Engle

On The Approximation Properties Of Partial Sums Of Trigonometric Fourier Series, Ushangi Goginava

Ushangi Goginava

On The Approximation Properties Of Cesàro Means Of Negative Order Of Walsh-Fourier Series, Ushangi Goginava

Ushangi Goginava

Detection Of Iapetan Rifting (Rome Trough Tectonism) By Quaternary Karstification: Pulaski County, Kentucky, Lee J. Florea

Lee J Florea, PhD, P.G.

The Importance Of The Normality Assumption In Large Public Health Data Sets, Paula Diehr, Thomas Lumley

Paula Diehr

Weight-Modification Trials In Older Adults: What Should The Outcome Measure Be?, Paula Diehr

Paula Diehr

A Comparison Of Haloe V19 With Sage Ii V6.00 Ozone Observations Using Trajectory Mapping, Gary A. Morris, James F. Gleason, James M. Russell Iii, Mark R. Schoeberl, M. Patrick Mccormick

Gary A. Morris

Unemployment Scarring In High Unemployment Regions, Claudio Lupi, Patrizia Ordine

Claudio Lupi

Rockets And Feathers Revisited: An International Comparison On European Gasoline Markets, Marzio Galeotti, Alessandro Lanza, Matteo Manera

Matteo Manera

Characterization Of Different Reactive Lysines In Bovine Heart Mitochondrial Porin. Al Jamal Ja, Philadelphia University

Philadelphia University, Jordan

Learning From The President’S Council On Sustainable Development: The Need For A Real National Strategy, John C. Dernbach

John C. Dernbach

Growing Correlation Length On Cooling Below The Onset Of Caging In A Simulated Glass-Forming Liquid, N. Lacevic, Francis W. Starr, T. B. Schrøder, V. N. Novikov, S. C. Glotzer

Francis Starr

Molecular Dynamics Simulation Of A Polymer Melt With A Nanoscopic Particle, Francis W. Starr, T. B. Schroder, S. C. Glotzer

Francis Starr

Transitions Between Inherent Structures In Water, Nicolas Giovambattista, Francis W. Starr, Francesco Sciortino, Sergey V. Buldyrev, H. Eugene Stanley

Francis Starr

Regression Analysis Of Recurrent Gap Times With Time-Dependent Covariates, Ying Qing Chen, Mei-Cheng Wang, Yijian Huang

U.C. Berkeley Division of Biostatistics Working Paper Series

Estimating Causal Parameters In Marginal Structural Models With Unmeasured Confounders Using Instrumental Variables, Tanya A. Henneman, Mark Johannes Van Der Laan, Alan E. Hubbard

U.C. Berkeley Division of Biostatistics Working Paper Series

Reactivity Profiles Of Ligands Of Mammalian Retinoic Acid Receptors: A Preliminary Corepa Analysis, Steven P. Bradbury, G. T. Ankley, O. G. Mekenyan, V. . Kamenska, P. K. Schmieder

Steven P. Bradbury

Narrowing Historical Uncertainty: Probabilistic Classification Of Ambiguously Identified Tree Species In Historical Forest Survey Data, David J. Mladenoff, Sally E. Dahir, Eric V. Nordheim, Lisa A. Schulte, Glenn G. Guntenspergen

Lisa A. Schulte Moore

Inclusive Gluon Production In Deep Inelastic Scattering At High Parton Density, Yuri V. Kovchegov, Kirill Tuchin

Kirill Tuchin

Three-Dimensional Landau Theory For Multivariant Stress-Induced Martensitic Phase Transformations. Ii. Multivariant Phase Transformations And Stress Space Analysis, Valery I. Levitas, Dean L. Preston

Valery I. Levitas

Three-Dimensional Landau Theory For Multivariant Stress-Induced Martensitic Phase Transformations. I. Austenite↔Martensite, Valery I. Levitas, Dean L. Preston

Valery I. Levitas

Low-Cost Manufacturing Process For Nanostructured Metals And Alloys, Travis L. Brown, Srinivasan Swaminathan, Srinivasan Chandrasekar, W. Dale Compton, Alexander H. King, Kevin P. Trumble

Alexander H. King

Climate Change: National Interests Or A Global Regime?, Maria Ivanova, Christiana Figueres

Maria Ivanova

Altitude Dependence Of Middleand Low-Latitude Thermospheric Disturbance Winds Measured By Windii, J. T. Emmert, Bela G. Fejer, G. G. Shepard, B. H. Solheim

Bela G. Fejer

Ultra-Dense Phosphorous Delta-Layer Grown Into Silicon From Ph3 Molecular Precursors, T. -C. Shen, J. -Y. Ji, M. A. Zudov, R. -R. Du, J. S. Kline, J. R. Tucker

T. -C. Shen

Star Formation In Bright Rimmed Clouds. I. Millimeter And Submillimeter Molecular Line Surveys, Christopher H. De Vries, Gopal Narayanan, Ronald L. Snell

Gopal Narayanan

Detection Of Infall Signatures Towards Serpens Smm4, Gopal Narayanan, G. Moriarty-Schieven, C.K. Walker, H.M. Butner

Gopal Narayanan

Low Latitude Ice Cores Record Pacific Sea Surface Temperatures, Raymond S. Bradley, M. Vuille, D. R. Hardy, L. G. Thompson

Raymond S Bradley