Miracle-dz/UniFAR-FTUs huggingface dataset:
Seasonal to Decadal Prediction of Southern African Climate and Its Links with Variability of the Atlantic Ocean

A review of the interannual to interdecadal variability of the southern African region and its links with the Atlantic is given. Emphasis is placed on modes such as the Benguela Nĩno that develop within the Atlantic and may have some predictability. Seasonal forecasting and climate prediction efforts within the region are discussed. Most southern African countries rely on a combination of products obtained overseas and simple statistical methods. GCM based forecasts and statistical downscaling of their outputs are used operationally in South Africa and also applied to some neighboring countries. A review of these downscaling efforts and their various applications is given. Research is also taking place into the predictability of quantities such as the onset of the rainy season (which appears to be associated with anomalous South Atlantic anticyclonic ridging) and dry spell frequencies within it. These parameters are often more useful to farmers in the region than forecasting above- or belowaverage seasona.
Depolarization of light in biological tissues: affect the polarization state by flow and estimation of flow rates

Recently in phototherapy the use of diodes and broadband light devices instead of lasers was suggested for economical and practical reasons. It has been argued that lasers have no preference over diodes since they lose their coherency and polarization once penetrating into biological tissues. In this talk we have for the first time experimentally validated the conditions that affect the polarization state of light when laser illumination is propagated through a biological tissue with and without a flow. In additional we will present physical modeling showing that illuminating a flow in a medium with linear polarized light can be highly correlated to the direction and rate of the flow through that medium.
Development of precision double corner cubes for the Space Interferometer Mission

NASA's Space Interferometer Mission (SIM) PlanetQuest requires, among other things, very precise retroreflectors. The CSIRO Australian Centre for Precision Optics (ACPO) has developed Double Corner Cubes (DCCs) to meet the requirements. The DCC consists of an assembly of three 30o wedged prisms optically contacted to a 132 mm diameter flat base plate. The material for all components was Zerodur. The specifications for the DCC were extremely challenging and posed considerable difficulties in the fabrication, coating, assembly, alignment and metrology. Some of the key specifications included: flatness of all reflecting surfaces to be ~ 10 nm peak to valley (P-V); dihedral angle errors < 0.5 arc seconds; collocation of the vertices of the two corner cubes within a circle of 5 um radius; all reflecting surfaces to be gold coated for a final microroughness < 0.5 nm rms; the clear or working aperture extended to within 0.2 mm of all physical edges; and the assembly had to withstand large vibrational forces. CSIRO delivered to JPL a DCC that was used as the primary unit in the so-called Kite testbed to satisfactorily meet the demonstration requirements of the SIM Milestone 8. This paper will discuss some of the procedures used to realize the DCCs and will show examples of results achieved.
Midinfrared quantum cascade detector with a spectrally broad response

A midinfrared quantum cascade detector with a spectrally broad (ΔE∕E=27.3%) response is designed, fabricated, and tested. This detector consists of 26 differently designed active region stages in order to cover a wavelength region from 4.7to7. 4μm. The device could be operated above room temperature and showed peak responsivities of 13mA∕W at 10K and 1.25mA∕W at room temperature. A background limited detectivity of 1.55×1010 Jones was seen up to a temperature TBLIP of 110K.
Diffusion-Assisted Aggregation and Synchronization in Dictyostelium discoideum

In biological pattern formation, chemotaxis and cell adhesion are essential. However, we lack quantitative data and a theory to understand their coordination. The cellular dynamics theory presented can clarify how Dictyostelium discoideum amoebae use diffusible cyclic adenosine ${3}^{\ensuremath{'}},{5}^{\ensuremath{'}}\ensuremath{-}\mathrm{monophosphate}$, and coordinate chemotaxis and cell adhesion during aggregation.
Comparative study of 1D and 2D flow simulations at open-channel junctions

In this paper, a comparison between the 1D and 2D approaches for simulating combining flows at open-channel junctions is presented. The two approaches are described allowing for a full comprehension of flow modelling. For flows in an open-channel network, mutual effects exist among the channel branches at a junction. Therefore, the 1D Saint-Venant equations for the branch flows are supplemented by various junction models. The existing models are of empirical nature and depend on the flow regime and thus are not practical in all cases. The numerical approximation of the two approaches is performed by the Runge–Kutta discontinuous Galerkin scheme and tested using defined flow problems to illustrate the results of the two approaches. Comparisons are conducted for supercritical, transitional and subcritical flows, indicating the validity range of the 1D approach and the advantages of the 2D approach.
A class of utility functions containing all the common utility functions

This paper presents a class of utility functions (class A \infty ) that contains all of the utility functions commonly used for mathematical modeling: the class consisting of those utility functions whose derivatives alternate in sign. A simple representation via mixtures of exponential utilities is provided for this class which is both mathematically convenient and conducive to functional operations. A connection with Laplace transforms and the resultant implications for preference relations, aggregation and utility assessment are discussed.
Effect of channel asymmetry on the behavior of flow passing through the glottis

A method for analyzing the behavior of flow passing through an asymmetrical glottal channel is presented. The method assumes the formation of a thin boundary layer near the glottal wall and an interaction between the boundary layer and the core flow. The core flow velocity is estimated in two dimensions employing a method of potential flow analysis, while the characteristic quantities of the boundary layer are determined by solving the integral momentum relation on the basis of the similarity of the velocity profiles within the layer. Estimation results for the volume flow rate, effective flow velocity, pressure distribution, driving force of the vocal folds, and flow separation point are presented for a total of 315 glottal configurations obtained by varying the angle of each vocal fold and the minimum glottal height. The results indicate that the boundary layer tends to reduce the effect of channel asymmetry, and the imbalance of the aerodynamic quantities between the two vocal folds is small unless the glottis widely opens and the angular difference of the vocal folds is considerable.
Variability of Monthly Diurnal Cycle Composites of TOA Radiative Fluxes in the Tropics

AbstractEarth system variability is generated by a number of different sources and time scales. Understanding sources of atmospheric variability is critical to reducing the uncertainty in climate models and to understanding the impacts of sampling on observational datasets. The diurnal cycle is a fundamental variability evident in many geophysical variables—including top-of-the-atmosphere (TOA) radiative fluxes. This study considers aspects of the TOA flux diurnal cycle not previously analyzed: namely, deseasonalized variations in the monthly diurnal cycle composites, termed monthly diurnal cycle variability. Significant variability in the monthly diurnal cycle composites is found in both outgoing longwave radiation (OLR) and reflected shortwave (RSW). OLR and RSW monthly diurnal cycle variability exhibits a regional structure that follows traditional, climatological diurnal cycle categorization by prevailing cloud and surface types. The results attribute monthly TOA flux diurnal cycle variability to vari.
Optical gain and collector current characteristics of resonant-cavity phototransistors

An analytic model for current gain as a function of optical input power in heterojunction bipolar phototransistors is developed. The model provides excellent agreement with the dc measurements of a resonant-cavity-enhanced heterojunction bipolar phototransistor. The model is extended to explain small-signal results.
Optimal experimental design for systems with bivariate failures under a bivariate Weibull function

In manufacturing industry, it may be important to study the relationship between machine component failures under stress. Examples include the failures of integrated circuits and memory chips in electronic merchandise given various levels of electronic shock. Such studies are important for the development of new products and for the improvement of existing products. We assume two‐component systems for simplicity and we assume that the joint probability of failures increases with stress as a cumulative bivariate Weibull function. Optimal designs have been developed for two correlated binary responses by using the Gumbel model, the bivariate binary Cox model and the bivariate probit model. In all these models, the amount of damage ranges from −∞ to ∞. In the Weibull model, the amount of damage is positive, which is natural for experimental factors such as voltage, tension or pressure. We describe locally optimal designs under bivariate Weibull assumptions. Since locally optimal designs with non‐linear models depend on predetermined parameter values, misspecified parameter values may lead to inefficient designs. However, we find that optimal designs under the Weibull model are surprisingly efficient over a wide range of misspecified parameter values. To improve the efficiency, we recommend a multistage procedure. We show how using a two‐stage procedure can provide a substantial improvement over a design that was optimal for misspecified parameters.
Waves at the electron plasma frequency associated with solar wind magnetic holes: STEREO/Cluster observations

[1] Magnetic depressions are common structures of the interplanetary medium. These magnetic holes can be just isolated dips of the amplitude of the field or they can be associated with discontinuities in the field orientation (tangential or rotational). Electrostatic waves at the plasma frequency (Langmuir waves) are often observed in these magnetic structures. The aim of the present paper is to provide the main characteristics of these waves and to propose a mechanism to explain their formation. The study is based on a statistical analysis of observations performed by STEREO (between March 2007 and August 2009) and Cluster (between 2002 and 2005) when each mission was in the free solar wind. Complementary information is provided by the two missions through the different instrumental configurations. We first provide new characteristics of the waves (polarization, energy, spectrum, occurrence). We then show that the occurrence of Langmuir waves activity inside a hole is closely linked to the presence of a significant electron strahl outside the hole. Finally, we propose a scenario for the generation of the Langmuir waves inside the holes.
LIMITATIONS IMPOSED ON STATISTICAL STUDIES OF GALACTIC SUPERNOVA REMNANTS BY OBSERVATIONAL SELECTION EFFECTS

The selection effects that apply to the identification of Galactic supernova remnants are reviewed together with the limitations that they impose on statistical studies. Emphasis is given to problems with recent discussions of the number, birthrate, and distribution of remnants within the Galaxy. The distribution of high-surface-brightness remnants is concentrated in a nuclear disk that is even more well-defined than that noted by van den Bergh 1988a,b. Also presented, as an appendix, are revisions to the catalog of Galactic supernova remnants presented in Green 1988. The revised catalog contains 174 remnants.
Analytic model for the runaway distribution function in the presence of spatial diffusion

A steady‐state kinetic model for runaway electrons in the presence of radial diffusion in a stochastic magnetic field is adopted and solved for a constant magnetic diffusivity. The model is constructed to recover the correct runaway production rate in the absence of spatial diffusion. The parallel energetic electron distribution function f is found by matching the solutions from three regions in parallel velocity space and is employed to form moments of f. Upper and lower bounds on the spatial diffusion are obtained by using these moments and the model exhibits the strong sensitivity to collisionality needed to explain the difference between similar plasmas with little or no hard x‐ray signal and those with significant hard x‐ray signals.
A General Approach to the Limiting Distribution for Estimators in Time Series Regression with Nonstable Autoregressive Errors

The authors consider the time series regression model where the error term follows a nonstable autoregressive process and present a general approach for delivering the limiting distribution of a normalized estimator for the autoregressive parameter. The present approach is quite straightforward and leads them to an accurate evaluation of the distribution function, unlike the other approaches suggested in the literature. The authors' methodology is illustrated and percent points are tabulated. The present approach produces a good approximation method for the finite sample distribution and also provides an accurate evaluation of the limiting powers of some unit root tests under a sequence of local alternatives. Copyright 1990 by The Econometric Society.
INVERSION FORMULAS FOR TRIDIAGONAL MATRICES WITH APPLICATIONS TO BOUNDARY VALUE PROBLEMS*

This paper first reviews some results on the structure of inverses of nonsingular and irreducible tridiagonal matrices. Next, explicit inversion formulas are given for certain, not necessarily symmetric, tridiagonal matrices. The results are then applied to matrices arising from discretization of two-point boundary value problems of the Sturm-Liouville type. The results show harmonic relations between the Green functions and the discrete Green functions for the problems. Finally the results are extended to block tridiagonal matrices. This work was supported by Scientific Research Grant-in-Aid from JSPS.
Theory and fluid simulations of boundary-plasma fluctuations

Theoretical and computational investigations of boundary-plasma microturbulence which take into account important effects of the geometry of diverted tokamaks—in particular, the effect of X-point magnetic shear and the termination of field lines on divertor plates—are presented. We first generalize our previous ‘heuristic boundary condition’ which describes, in a lumped model, the closure of currents in the vicinity of the X-point region to encompass three current-closure mechanisms. We then use this boundary condition to derive the dispersion relation for low-beta flute-like modes in the divertor-leg region under the combined drives of curvature, sheath impedance and divertor tilt effects. The results indicate the possibility of strongly growing instabilities, driven by sheath boundary conditions, and localized in either the private or common flux region of the divertor leg depending on the radial tilt of divertor plates. We revisit the issue of X-point effects on blobs, examining the transition from blobs terminated by X-point shear to blobs that extend over both the main SOL and divertor legs. We find that, for a main-SOL blob, this transition occurs without a free-acceleration period as previously thought, with X-point termination conditions applying until the blob has expanded to reach the divertor plate. We also derive propagation speeds for divertor-leg blobs. Finally, we present fluid simulations of the C-Mod tokamak from the BOUT edge fluid turbulence code, which show main-SOL blob structures with similar spatial characteristics to those observed in the experiment, and also simulations which illustrate the possibility of fluctuations confined to divertor legs.
Callisto plasma interactions: Hybrid modeling including induction by a subsurface ocean

By using a hybrid plasma solver (ions as particles and electrons as a fluid), we have modeled the interaction between Callisto and Jupiter's magnetosphere for variable ambient plasma parameters. We compared the results with the magnetometer data from flybys (C3, C9, and C10) by the Galileo spacecraft. Modeling the interaction between Callisto and Jupiter's magnetosphere is important to establish the origin of the magnetic field perturbations observed by Galileo and thought to be related to a subsurface ocean. Using typical upstream magnetospheric plasma parameters and a magnetic dipole corresponding to the inductive response inside the moon, we show that the model results agree well with observations for the C3 and C9 flybys, but agrees poorly with the C10 flyby close to Callisto. The study does support the existence of a subsurface ocean at Callisto.
MEASUREMENT OF THE VELOCITY‐FIELD CHARACTERISTIC OF GALLIUM ARSENIDE

The electron velocity‐field characteristic of insulating GaAs has been measured by injecting electrons with an electron beam. The measured low field mobility is 7500 cm2/V‐sec with an initial negative differential mobility of −2400 cm2/V‐sec at a threshold field of 3.2 kV/cm.
Detonating Failed Deflagration Model of Thermonuclear Supernovae. I. Explosion Dynamics

We present a detonating failed deflagration model of Type Ia supernovae. In this model, the thermonuclear explosion of a massive white dwarf follows an off-center deflagration. We conduct a survey of asymmetric ignition configurations initiated at various distances from the stellar center. In all cases studied, we find that only a small amount of stellar fuel is consumed during deflagration phase, no explosion is obtained, and the released energy is mostly wasted on expanding the progenitor. Products of the failed deflagration quickly reach the stellar surface, polluting and strongly disturbing it. These disturbances eventually evolve into small and isolated shock-dominated regions that are rich in fuel. We consider these regions as seeds capable of forming self-sustained detonations that, ultimately, result in the thermonuclear supernova explosion. Preliminary nucleosynthesis results indicate that the model supernova ejecta are typically composed of about 0.1-0.25 M☉ of silicon group elements and 0.9-1.2 M☉ of iron group elements and are essentially carbon-free. The ejecta have a composite morphology, are chemically stratified, and display a modest amount of intrinsic asymmetry. The innermost layers are slightly egg shaped with the axis ratio ≈1.2-1.3 and dominated by the products of silicon burning. This central region is surrounded by a shell of silicon group elements. The outermost layers of ejecta are highly inhomogeneous and contain products of incomplete oxygen burning with only small admixture of unburned stellar material. The explosion energies are ≈(1.3-1.5) × 1051 ergs.
Radiative–convective equilibrium in a three‐dimensional cloud‐ensemble model

A knowledge of radiative convective interactions is key to an understanding of the tropical climate. In an attempt to address this a cloud‐resolving model has been run to a radiative‐convective equilibrium state in three dimensions. The model includes a three‐phase bulk microphysical scheme and a fully interactive two‐stream broadband radiative‐transfer scheme for both the infrared and solar radiation. The simulation is performed using a fixed sea surface temperature, and cyclic lateral boundary conditions. No ‘large‐scale’ convergence, mean wind shear or background vorticity was imposed.
Ab initio study of helium in α-Fe : Dissolution, migration, and clustering with vacancies

Density functional theory calculations have been performed to study the dissolution and migration of helium in $\ensuremath{\alpha}$-iron, and the stability of small helium-vacancy clusters ${\mathrm{He}}_{n}{V}_{m}$ ($n$,$m=0$ to 4). Substitutional and interstitial configurations of helium are found to have similar stabilities. The tetrahedral configuration is more stable than the octahedral by 0.2 eV. Interstitial helium atoms are predicted to have attractive interactions and a very low migration energy (0.06 eV), suggesting that He bubbles can form at low temperatures in initially vacancy-free lattices. The migration of substitutional helium by the vacancy mechanism is governed by the migration of the ${\mathrm{HeV}}_{2}$ complex, with an energy barrier of 1.1 eV. The activation energies for helium diffusion by the dissociation and vacancy mechanisms are estimated for the limiting cases of thermal-vacancy regime and of high supersaturation of vacancies. The trends of the binding energies of vacancy and helium to helium-vacancy clusters are discussed in terms of providing additional knowledge on the behavior of He in irradiated iron, necessary for the interpretation of complex experimental data such as thermal He desorption spectra.
Perturbation Analysis for Blood Flow in Stenosed Arteries under Body Acceleration

In this theoretical study, the pulsatile flow of a two-fluid model for blood in narrow arteries with mild stenosis under periodic body acceleration is analyzed. The suspension of all the erythrocytes in the core region is assumed as Herschel-Bulkley fluid and the plasma in the peripheral layer region is treated as Newtonian fluid. Perturbation method is used to solve the resulting system of nonlinear partial differential equations. The expressions for the physiologically important flow quantities such as velocity, wall shear stress, plug core radius, flow rate and longitudinal impedance to flow are obtained. The effects of the parameters( body acceleration, depth of the stenosis, yield stress, width of the peripheral layer, pulsatility and lead angle) on these flow quantities are analyzed through appropriate graphs. It is observed that the plug core radius, wall shear stress and longitudinal impedance to flow increase with the increase of the yield stress, lead angle and stenosis depth. It is found that the velocity and flow rate increase with the increase of the pulsatile Reynolds number, body acceleration, pressure gradient and width of the peripheral layer thickness. It is also noted that the wall shear stress and longitudinal impedance to flow are considerably lower for the two-fluid Herschel-Bulkley model than that of the single-fluid Herschel-Bulkley model. Also, it is noticed that the estimates of the mean flow rate and mean velocity increase significantly with the increase of body acceleration and peripheral layer. K e y w o r d s : Mathematical modeling; Perturbation method; Nonlinear model; Pulsatile blood flow; Effect of body acceleration
A Tool for Computing Confidence Regions on the Stationary Point of a Response Surface

This article describes a software tool for the computation and display of confidence regions on the location of the stationary point of a quadratic response surface. The algebraic complexity of the computation and plotting of these regions makes such a task ideally suited for a computer algebra system. The program, coded in the computer algebra package MAPLE, has been used in a graduate level class in response surface methodology (RSM). Three examples taken from the literature illustrate the use and features of the program.