bluuebunny/crossref_metadata_2025 huggingface dataset:
PCCHUA — A LABORATORY SETUP FOR REAL-TIME CONTROL AND SYNCHRONIZATION OF CHAOTIC OSCILLATIONS
Authors: TÔRRES LEONARDO A. B. , AGUIRRE LUIS ANTONIO
Published: September 2005

This paper describes a laboratory setup suitable for implementing low cost real-time solutions in the fields of control, synchronization and information transmission based on chaotic oscillators. The setup has the following features: (a) it is composed of a Chua oscillator furnished with three actuators thus permitting mono- and multi-variable control; (b) the actuators can be driven by the analog outputs of a standard I/O-board; in order to be able to actuate fast enough (c) the I/O-board is driven by a real time program written for Linux and (d) an inductorless implementation of Chua's circuit permits to slow down the original dynamics to just a few hertz. This enables implementing sophisticated control schemes without severe time restrictions. The paper concludes with a sample of experiments performed using the new setup.
ENUMERATION OF HOMOGENEOUS COUPLED CELL NETWORKS
Authors: ALDOSRAY FALIH , STEWART IAN
Published: September 2005

A coupled cell network is a schematic diagram employed to define a class of differential equations, and can be thought of as a directed graph whose nodes (cells) represent dynamical systems and whose edges (arrows) represent couplings. Often the nodes and edges are labeled to distinguish different types of system and coupling. The associated differential equations reflect this structure in a natural manner. The network is homogeneous if there is one type of cell and one type of arrow, and moreover, every cell lies at the head end of the same number r of arrows. This number is the valency of the network. We use a group-theoretic formula usually but incorrectly attributed to William Burnside to enumerate homogeneous coupled cell networks with N cells and valency r, in both the disconnected and connected cases. We compute these numbers explicitly when N, r ≤ 6.
NEURAL NETWORK-BASED DIGITAL REDESIGN APPROACH FOR CONTROL OF UNKNOWN CONTINUOUS-TIME CHAOTIC SYSTEMS
Authors: CANELON JOSE I. , SHIEH LEANG S. , GUO SHU M. , MALKI HEIDAR A.
Published: September 2005

This paper presents a neural network-based digital redesign approach for digital control of continuous-time chaotic systems with unknown structures and parameters. Important features of the method are that: (i) it generalizes the existing optimal linearization approach for the class of state-space models which are nonlinear in the state but linear in the input, to models which are nonlinear in both the state and the input; (ii) it develops a neural network-based universal optimal linear state-space model for unknown chaotic systems; (iii) it develops an anti-digital redesign approach for indirectly estimating an analog control law from a fast-rate digital control law without utilizing the analog models. The estimated analog control law is then converted to a slow-rate digital control law via the prediction-based digital redesign method; (iv) it develops a linear time-varying piecewise-constant low-gain tracker which can be implemented using microprocessors. Illustrative examples are presented to demonstrate the effectiveness of the proposed methodology.
FREQUENCY DOMAIN METHOD FOR THE DICHOTOMY OF MODIFIED CHUA'S EQUATIONS
Authors: DUAN ZHISHENG , WANG JIN-ZHI , HUANG LIN
Published: September 2005

On condition of dichotomy, it is pointed out that in Lorenz and a kind of Rössler-like system chaotic attractors or limit cycles will disappear if nonlinearity of the product of two variables is replaced by some single variable nonlinearity, for example, nonlinearity of Chua's circuit. Furthermore, an extended Chua's circuit with two nonlinear functions is presented. By computer simulation it is shown that oscillating phenomena in the extended Chua's circuit are richer than the single Chua's circuit. The corresponding extension for smooth Chua's equations is also considered. The effects of input and output coupling are analyzed for the extended Chua's circuit.
ON THE APPROXIMATE ONE-D MAP IN CHUA'S OSCILLATOR
Authors: FORBES PEADAR , BOYLE SARAH , O'DONOGHUE KEITH , KENNEDY MICHAEL PETER
Published: September 2005

Due to strong contraction in the outer regions of Chua's circuit with piecewise-linear dynamics, the system can be described by an approximate one-dimensional map. We confirm by simulation and experiment that the initial slope of this map is defined by [Formula: see text].
AN EXPERIMENTAL STUDY ON CHAOTIC DYNAMICS OF CFOA-BASED SC-CNN CIRCUIT
Authors: GÜNAY ENIS , ALÇI MUSTAFA , YILDIRIM FATMA
Published: September 2005

In this paper, an experimental implementation of State Controlled Cellular Neural Network (SC-CNN) circuit using Current Feedback Op Amp (CFOA) is presented and its chaotic dynamics including high frequency performance are investigated by laboratory experiments. Depending on its significant advantages over the conventional voltage op amps (VOAs), without imposing any restrictions, the CFOAs have been used instead of the VOAs in SC-CNN circuit. Experimental results have shown that the proposed implementation has a capacity of higher frequency operation.
A SYSTEM INVERSION APPROACH TO CHAOS-BASED SECURE SPEECH COMMUNICATION
Authors: ZHENG YUFAN , CHEN GUANRONG , ZHU CANYAN
Published: September 2005

A new approach to real-time secure speech communication is proposed based on the inversion theory of nonlinear discrete-time dynamical systems. The proposed approach uses an observable minimal-phase nonlinear discrete-time dynamical system, particularly with chaotic zero-dynamics, as the drive system to generate encrypted speech signals for transmission. The receiver is the minimal left-inverse system of the drive system. The receiver decrypts the received signal and recovers the original message in real-time. The effectiveness of the proposed approach and design is demonstrated via examples for secure speech signal transmission. Performance evaluation of the designed secure communication system is discussed. Both analysis and simulation show that the new scheme is relatively secure but simple, accurate and robust, suitable for some civil and commercial voice-communication applications.
NORMALIZED HISTOGRAM OF THE STATE VARIABLE OF FIRST-ORDER DIGITAL FILTERS WITH TWO'S COMPLEMENT ARITHMETIC
Authors: LING BINGO WING-KUEN , HO CHARLOTTE YUK-FAN , TAM PETER KWONG-SHUN
Published: September 2005

In this Letter, the normalized histogram of the state variable of first-order digital filters with two's complement arithmetic is investigated. When the pole of the digital filter is between 1 and 2, it is found that the possibility of occurrence of state variable in certain regions is close to zero no matter what is the initial condition. Some analytic results are given to account for this phenomenon.
RESHAPING-INDUCED CHAOTIC ESCAPE FROM A POTENTIAL WELL
Authors: CHACÓN R. , MARTÍNEZ J. A.
Published: September 2005

The chaotic escape of a damped oscillator excited by a periodic string of symmetric pulses of finite width and amplitude from a cubic potential well that typically models a metastable system close to a fold is investigated. Analytical (Melnikov analysis) and numerical results show that chaotic escapes are typically induced over a wide range of parameters by hump-doubling of an external excitation which is initially formed by a periodic string of single-humped symmetric pulses. The analysis reveals that the threshold amplitude for chaotic escape when altering solely the pulse shape presents a minimum as a single-humped pulse transforms into a double-humped pulse, the remaining parameters being held constant. We discuss a physical mechanism concerning the impulse transmitted by the pulse which explains the aforementioned results.
CHAOTIFYING FUZZY HYPERBOLIC MODEL USING IMPULSIVE AND NONLINEAR FEEDBACK CONTROL APPROACHES
Authors: ZHANG HUAGUANG , WANG ZHILIANG , LIU DERONG
Published: September 2005

In this paper, the problem of chaotifying the continuous-time fuzzy hyperbolic model (FHM) is considered. We use impulsive and nonlinear feedback control methods to chaotify the FHM and show that chaos produced by the present methods satisfy the three criteria of Devaney. Computer simulations will be used to verify the present results.
HOPF BIFURCATION CONTROL FOR AN INTERNET CONGESTION MODEL
Authors: CHEN Z. , YU P.
Published: September 2005

In this note, we consider Hopf bifurcation control for an Internet congestion model with a single route accessed by a single source. It has been shown that the system without control cannot guarantee a stationary sending rate. As the positive gain parameter of the system passes a critical point, Hopf bifurcation occurs. To control the Hopf bifurcation, a time-delayed feedback controller using polynomial function is proposed to delay the onset of undesirable Hopf bifurcation. Numerical simulation results confirm that the new feedback controller using time delay is efficient in controlling Hopf bifurcation. This approach can be extended to study higher dimensional delay differential equations.
BIFURCATION OF LIMIT CYCLES FROM A FOUR-DIMENSIONAL CENTER IN CONTROL SYSTEMS
Authors: BUICĂ ADRIANA , LLIBRE JAUME
Published: September 2005

We study the bifurcation of limit cycles from the periodic orbits of a four-dimensional center in a class of piecewise linear differential systems, which appears in a natural way in control theory. Our main result shows that three is an upper bound for the number of limit cycles, up to first-order expansion of the displacement function with respect to the small parameter. Moreover, this upper bound is reached. For proving this result we use the averaging method in a form where the differentiability of the system is not needed.
BIFURCATION FROM ZERO OF A COMPLETE TRAJECTORY FOR NONAUTONOMOUS LOGISTIC PDES
Authors: LANGA JOSÉ A. , ROBINSON JAMES C. , SUÁREZ ANTONIO
Published: September 2005

In this paper we extend the well-known bifurcation theory for autonomous logistic equations to the nonautonomous equation [Formula: see text]0 < b0 < B0 < 2b0. In particular, we prove the existence of a unique uniformly bounded trajectory that bifurcates from zero as λ passes through the first eigenvalue of the Laplacian, which attracts all other trajectories. Although it is this relatively simple equation that we analyze in detail, other more involved models can be treated using similar techniques.
NUMERICAL INVESTIGATION OF PERIODIC MOTION IN THE THREE-DIMENSIONAL RING PROBLEM OF N BODIES
Authors: HADJIFOTINOU K. G. , KALVOURIDIS T. J.
Published: September 2005

We study numerically the three-dimensional periodic motion of a massless particle in an annular configuration of N bodies. This ring model can approximate the dynamics of celestial systems like clusters and planetary rings. After calculating numerically the families of x-symmetric periodic orbits in the planar case for a certain N, we investigate the families' vertical stability and locate those members that present critical instability in the eigenvalues corresponding to the z-axis. These orbits are the points of bifurcation of the planar families of periodic orbits to three-dimensional families. By means of differentially correcting the vertically critical orbits we extend our numerical investigation in the three-dimensional space and locate several families of three-dimensional periodic orbits symmetric to the xz-plane. The evolution of the families and the significant features of their members are subsequently presented.
GENERALIZED KINK WAVES IN A GENERAL COMPRESSIBLE HYPERELASTIC ROD
Authors: LIU ZHENGRONG , LONG YAO
Published: September 2005

In this paper, we employ both qualitative analysis and numerical simulation to investigate bounded traveling waves in a general compressible hyperelastic rod. Some new bounded traveling waves are found. Their implicit expressions are obtained. Also, their planar graphs are simulated. Since they possess some properties of kink waves, we call them generalized kink waves.
ENaC proteins are required for NGF-induced neurite growth
Authors: Drummond Heather A. , Furtado Marise M. , Myers Samuel , Grifoni Samira , Parker Kimberly A. , Hoover Angela , Stec David E.
Published: September 2005

Neurite growth is required for nervous system development and repair. Multiple signals, including neurotrophic factors and intact mechanosensing mechanisms, interact to regulate neurite growth. Degenerin/epithelial Na+ channel (DEG/ENaC) proteins have been identified as putative mechanosensors in sensory neurons. Recently, others have shown that the neurotrophic factor NGF stimulates expression of acid-sensing ion channel molecules, which are members of the DEG/ENaC family. However, it is unknown whether NGF regulates ENaC expression or whether ENaC expression is required for neurite formation. Therefore, the aims of the present study were to determine whether ENaC expression is 1) regulated by NGF and 2) required for NGF-induced neurite growth in pheochromocytoma PC-12 cells. We found NGF-induced expression of β- and γ-subunits of ENaC, but not α-ENaC. Tyrosine kinase A (TrkA) receptor blockade abolished NGF-induced β- and γ-ENaC expression and neurite formation. NGF-induced neurite formation was inhibited by disruption of ENaC expression using 1) pharmacological blockade with benzamil, a specific ENaC inhibitor; 2) small interfering RNA; and 3) dominant-negative ENaC molecules. These data indicate NGF-TrkA regulation of ENaC expression may be required for neurite growth and may suggest a novel role for DEG/ENaC proteins in neuronal remodeling and differentiation.
Age-associated decrease in muscle precursor cell differentiation
Authors: Lees Simon J. , Rathbone Christopher R. , Booth Frank W.
Published: September 2005

Muscle precursor cells (MPCs) are required for the regrowth, regeneration, and/or hypertrophy of skeletal muscle, which are deficient in sarcopenia. In the present investigation, we have addressed the issue of age-associated changes in MPC differentiation. MPCs, including satellite cells, were isolated from both young and old rat skeletal muscle with a high degree of myogenic purity (>90% MyoD and desmin positive). MPCs isolated from skeletal muscle of 32-mo-old rats exhibited decreased differentiation into myotubes and demonstrated decreased myosin heavy chain (MHC) and muscle creatine kinase (CK-M) expression compared with MPCs isolated from 3-mo-old rats. p27Kip1 is a cyclin-dependent kinase inhibitor that has been shown to enhance muscle differentiation in culture. Herein we describe our finding that p27Kip1 protein was lower in differentiating MPCs from skeletal muscle of 32-mo-old rats than in 3-mo-old rat skeletal muscle. Although MHC and CK-M expression were ∼50% lower in differentiating MPCs isolated from 32-mo-old rats, MyoD protein content was not different and myogenin protein concentration was twofold higher. These data suggest that there are inherent differences in cell signaling during the transition from cell cycle arrest to the formation of myotubes in MPCs isolated from sarcopenic muscle. Furthermore, there is an age-associated decrease in muscle-specific protein expression in differentiating MPCs despite normal MyoD and elevated myogenin levels.
De novo myofibrillogenesis in C2C12 cells: evidence for the independent assembly of M bands and Z disks
Authors: Kontrogianni-Konstantopoulos Aikaterini , Catino Dawn H. , Strong John C. , Bloch Robert J.
Published: October 2005

We studied the distribution of the giant sarcomeric protein obscurin during de novo myofibrillogenesis in C2C12 myotubes to learn when it is integrated into developing sarcomeres. Obscurin becomes organized first at the developing M band and later at the mature Z disk. Primordial M bands consisting of obscurin, myomesin, and M band epitopes of titin assemble before adult fast-twitch sarcomeric myosin is organized periodically and nearly concurrently with primitive Z disks, which are composed of α-actinin and Z disk epitopes of titin. Z disks and M bands can assemble independently at spatially distant sites. As sarcomerogenesis proceeds, these structures interdigitate to produce a more mature organization. Fast-twitch muscle myosin accumulates in the myoplasm and assembles into A bands only after Z disks and M bands assume their typical interdigitated striations. The periodicities of M bands remain constant at ∼1.8 μm throughout sarcomerogenesis, whereas distances between Z disks increase from ∼1.1 μm in early sarcomeres to ∼1.8 μm in more mature structures. Our findings indicate for the first time that primitive M bands self-assemble independently of Z disks, that obscurin is a component of these primitive M bands in skeletal muscle cells, and that A bands assemble only after M bands and Z disks integrate into maturing sarcomeres.
Neuronal activity within the ventrolateral periaqueductal gray during simulated hemorrhage in conscious rabbits
Authors: Schadt James C. , Shafford Heidi L. , McKown Michael D.
Published: September 2005

The ventrolateral (vl) periaqueductal gray (PAG) has been proposed as a site responsible for the active process triggering the onset of hypotension (i.e., phase 2) during blood loss in conscious animals (Cavun S and Millington WR. Am J Physiol Regul Integr Comp Physiol 281: R747–R752, 2001). We recorded the extracellular activity of PAG neurons in conscious rabbits to test the hypothesis that vlPAG neurons change their firing frequency before the onset of hypotension during simulated hemorrhage. Arterial and venous catheters, an intrathoracic vena caval occluder, and midbrain microelectrodes on a microdrive were implanted in 10 rabbits. During simulated hemorrhage, the occluder was inflated until arterial pressure ≤40 mmHg. We compared changes in neuronal activity during simulated hemorrhage with those during a similar length control period for 64 vlPAG and 29 dorsolateral (dl) PAG neurons. Arterial pressure pulse modulation of neuronal activity was present in 45 and 76% of vlPAG and dlPAG neurons, respectively. When we evaluated the absolute change in activity, thus accounting for both increases and decreases, simulated hemorrhage had a significant effect on activity of vlPAG but not dlPAG neurons. The majority (56%) of vlPAG neurons did not appear to respond to simulated hemorrhage. Of the 28 responsive vlPAG neurons, 11 showed an abrupt change in firing frequency during the time interval preceding the onset of hypotension; 13 responded after the onset of hypotension; and 4 showed a consistent direction of change across the entire simulated hemorrhage. Thus 24 (38%) of the vlPAG neurons recorded responded at a time consistent with a contribution to the hypotension associated with simulated hemorrhage.
Different Neural Correlates of Reward Expectation and Reward Expectation Error in the Putamen and Caudate Nucleus During Stimulus-Action-Reward Association Learning
Authors: Haruno Masahiko , Kawato Mitsuo
Published: September 2005

To select appropriate behaviors leading to rewards, the brain needs to learn associations among sensory stimuli, selected behaviors, and rewards. Recent imaging and neural-recording studies have revealed that the dorsal striatum plays an important role in learning such stimulus-action-reward associations. However, the putamen and caudate nucleus are embedded in distinct cortico-striatal loop circuits, predominantly connected to motor-related cerebral cortical areas and frontal association areas, respectively. This difference in their cortical connections suggests that the putamen and caudate nucleus are engaged in different functional aspects of stimulus-action-reward association learning. To determine whether this is the case, we conducted an event-related and computational model–based functional MRI (fMRI) study with a stochastic decision-making task in which a stimulus-action-reward association must be learned. A simple reinforcement learning model not only reproduced the subject's action selections reasonably well but also allowed us to quantitatively estimate each subject's temporal profiles of stimulus-action-reward association and reward-prediction error during learning trials. These two internal representations were used in the fMRI correlation analysis. The results revealed that neural correlates of the stimulus-action-reward association reside in the putamen, whereas a correlation with reward-prediction error was found largely in the caudate nucleus and ventral striatum. These nonuniform spatiotemporal distributions of neural correlates within the dorsal striatum were maintained consistently at various levels of task difficulty, suggesting a functional difference in the dorsal striatum between the putamen and caudate nucleus during stimulus-action-reward association learning.
Duration Selective Neurons in the Inferior Colliculus of the Rat: Topographic Distribution and Relation of Duration Sensitivity to Other Response Properties
Authors: Pérez-González D. , Malmierca M. S. , Moore J. M. , Hernández O. , Covey E.
Published: September 2005

Many animals use duration to help them identify the source and meaning of a sound. Duration-sensitive neurons have been found in the auditory midbrain of mammals and amphibians, where their selectivity seems to correspond to the lengths of species-specific vocalizations. In this study, single neurons in the rat inferior colliculus (IC) were tested for sensitivity to sound duration. About one-half (54%) of the units sampled showed some form of duration selectivity. The majority of these (76%) were long-pass neurons that responded to sounds exceeding some duration threshold (range: 5–60 ms). Band-pass neurons, which only responded to a restricted range of durations, made up 13% of duration-sensitive neurons (best durations: 15–120 ms). Other units displayed short-pass (2%) or mixed (9%) response patterns. The majority of duration-sensitive neurons were localized outside the central nucleus of the IC, especially in the dorsal cortex, where more than one-half of the neurons sampled had long-pass selectivity for duration. Band-pass duration tuned neurons were only found outside the central nucleus. Characteristics of duration-sensitive neurons in the rat support the idea that this filtering arises through an interaction of excitatory and inhibitory inputs that converge in the IC. Band-pass neurons typically responded at sound offset, suggesting that their tuning is created through the same mechanisms that have been described in echolocating bats. The finding that the first-spike latencies of all long-pass neurons were longer than the shortest duration to which they responded supports the idea that they receive transient inhibition before, or simultaneously with, a sustained excitatory input. The ranges of selectivity in rat IC neurons are within the range of durations of rat vocalizations. These data suggest that a population of neurons in the rat IC have evolved to transmit information about behaviorally relevant sound durations using mechanisms that are common to all mammals, with an emphasis on long-pass tuning characteristics.
Psychophysical Elements of Place and Modality Specificity in the Thalamic Somatic Sensory Nucleus (Ventral Caudal, Vc) of Awake Humans
Authors: Patel S. , Ohara S. , Dougherty P. M. , Gracely R. H. , Lenz F. A.
Published: September 2005

Discrete anatomic structures in the monkey somatic sensory thalamus may segregate input arising from different peripheral receptors and from different parts of the body. It has been proposed that these structures serve as components of modality- and place-specific pathways from the periphery to the cortex. We now test this hypothesis by examining the modality- and place-specific segregation of sensations at sites where microstimulation (μA currents) within the region of ventral caudal (Vc; human principal somatic sensory nucleus) evokes somatic sensations. Microstimulation was delivered in an ascending staircase protocol consisting of different numbers of pulses (4–100) presented at different frequencies (10–200 Hz) during awake thalamic surgery for movement disorders. The results demonstrate that the part of the body where microstimulation evoked sensation (projected field) and the descriptors of nonpainful sensations were usually uniform across the staircase. These results strongly support the existence of psychophysical elements of place and modality specificity in the Vc thalamus. The proportion of sites at which the sensation included more than one part of the body almost always stayed constant over current intervals (plateaus) of 10 μA. Similar plateaus were not found for sites with more than one descriptor, suggesting that elements of modality-specificity are smaller than and located within those for place-specificity. The intensity of sensations varied with the number of stimulation pulses for mechanical/tingle and cool sensations. The results provide strong evidence for psychophysically defined elements that are responsible for modality specificity of nonpainful sensations, place specificity, and intensity coding of somatic sensation in the human thalamus.
Virtual Vocalization Stimuli for Investigating Neural Representations of Species-Specific Vocalizations
Authors: DiMattina Christopher , Wang Xiaoqin
Published: October 2005

Most studies investigating neural representations of species-specific vocalizations in non-human primates and other species have involved studying neural responses to vocalization tokens. One limitation of such approaches is the difficulty in determining which acoustical features of vocalizations evoke neural responses. Traditionally used filtering techniques are often inadequate in manipulating features of complex vocalizations. Furthermore, the use of vocalization tokens cannot fully account for intrinsic stochastic variations of vocalizations that are crucial in understanding the neural codes for categorizing and discriminating vocalizations differing along multiple feature dimensions. In this work, we have taken a rigorous and novel approach to the study of species-specific vocalization processing by creating parametric “virtual vocalization” models of major call types produced by the common marmoset ( Callithrix jacchus). The main findings are as follows. 1) Acoustical parameters were measured from a database of the four major call types of the common marmoset. This database was obtained from eight different individuals, and for each individual, we typically obtained hundreds of samples of each major call type. 2) These feature measurements were employed to parameterize models defining representative virtual vocalizations of each call type for each of the eight animals as well as an overall species-representative virtual vocalization averaged across individuals for each call type. 3) Using the same feature-measurement that was applied to the vocalization samples, we measured acoustical features of the virtual vocalizations, including features not explicitly modeled and found the virtual vocalizations to be statistically representative of the callers and call types. 4) The accuracy of the virtual vocalizations was further confirmed by comparing neural responses to real and synthetic virtual vocalizations recorded from awake marmoset auditory cortex. We found a strong agreement between the responses to token vocalizations and their synthetic counterparts. 5) We demonstrated how these virtual vocalization stimuli could be employed to precisely and quantitatively define the notion of vocalization “selectivity” by using stimuli with parameter values both within and outside the naturally occurring ranges. We also showed the potential of the virtual vocalization stimuli in studying issues related to vocalization categorizations by morphing between different call types and individual callers.
Slow Dynamics of Postural Sway Are in the Feedback Loop
Authors: Kiemel Tim , Oie Kelvin S. , Jeka John J.
Published: September 2005

Postural sway is considered to have two fundamental stochastic components, a slow nonoscillatory component and a faster damped-oscillatory component. The slow component has been shown to account for the majority of sway variance during quiet stance. Postural control is generally viewed as a feedback loop in which sway is detected by sensory systems and appropriate motor commands are generated to stabilize the body's orientation. Whereas the mechanistic source for the damped-oscillatory sway component is most likely feedback control of an inverted pendulum, the underlying basis for the slow component is less clear. We investigated whether the slow process was inside or outside the feedback loop by providing standing subjects with sum-of-sines visual motion. Linear stochastic models were fit to the experimental sway trajectories to determine the stochastic structure of sway as well as the transfer function from visual motion to sway. The results supported a fifth-order stochastic model, consisting of a slow process and two damped-oscillatory components. Importantly, the slow process was determined to be inside the feedback loop. This supports the hypothesis that the slow component is due to errors in state estimation because state estimation is inside the feedback loop rather than a moving reference point or an exploratory process outside the feedback loop.
Ground Heat Flux Determination according to Land Skin Temperature Observations from In Situ Stations and Satellites
Authors: Tsuang Ben-Jei
Published: September 2005

Due to rapid progress in the development of remote sensing techniques, skin temperature can now be observed with global coverage from satellites. This study derives an equation for utilizing skin temperature measurements to determine ground heat flux. This equation is verified at the First International Satellite Land Surface Climatology Project (ISLSCP) Field Experiment (FIFE) campaign site and four Fluxnet sites. A preliminary monthly global dataset of ground heat flux with 1° resolution, covering the years 1984–95, is derived based on skin temperature observations obtained via satellite. It shows that the seasonal variation of ground heat flux over land can be determined at 1.5 months ahead by observing the increasing rate of skin temperature, and that the variation increases from ±2 W m−2 at the equator to ±20 W m−2 at the poles. Over land, the resulting ground heat flux can be compared with that of the ERA-15 reanalysis, showing rms differences of about 4 W m−2.
Evaluation of Soil Moisture in the NCEP–NCAR and NCEP–DOE Global Reanalyses
Authors: Lu Cheng-Hsuan , Kanamitsu Masao , Roads John O. , Ebisuzaki Wesley , Mitchell Kenneth E. , Lohmann Dag
Published: September 2005

This study compares soil moisture analyses from the National Centers for Environmental Prediction–National Center for Atmospheric Research (NCEP–NCAR) global reanalysis (R-1) and the later NCEP– Department of Energy (DOE) Atmospheric Model Intercomparison Project (AMIP) global reanalysis (R-2). The R-1 soil moisture is strongly controlled by nudging it to a prescribed climatology, whereas the R-2 soil moisture is adjusted according to differences between model-generated and observed precipitation. While mean soil moisture fields from R-1 and R-2 show many geographic similarities, there are some major differences. This study uses in situ observations from the Global Soil Moisture Data Bank to evaluate the two global reanalysis products. In general, R-2 does a better job of simulating interannual variations, the mean seasonal cycle, and the persistence of soil moisture, when compared to observations. However, the R-2 reanalysis does not necessarily represent observed soil moisture characteristics well in all aspects. Sometimes R-1 provides a better soil moisture analysis on monthly time scales, which is likely a consequence of the deficiencies in the R-2 surface water balance.
Transport of Atmospheric Moisture during Three Extreme Rainfall Events over the Mackenzie River Basin
Authors: Brimelow Julian C. , Reuter Gerhard W.
Published: September 2005

Lagrangian trajectories were computed for three extreme summer rainfall events (with rainfall exceeding 100 mm) over the southern Mackenzie River basin to test the hypothesis that the low-level moisture feeding these rainstorms can be traced back to the Gulf of Mexico. The three-dimensional trajectories were computed using the Hybrid Single-Particle Lagrangian Integrated Trajectory model (HYSPLIT).

For all three events, parcel trajectories were identified that originated near the Gulf of Mexico and terminated over the southern Mackenzie River basin. Specifically, the transport of low-level moisture was found to occur along either quasi-continuous or stepwise trajectories. The time required to complete the journey varied between 6 and 10 days.

Closer examination of the data suggests that, for the three cases in question, the transport of modified Gulf of Mexico moisture to high latitudes was realized when the northward extension of the Great Plains low-level jet to the Dakotas occurred in synch with rapid cyclogenesis over Alberta, Canada. In this way, modified low-level moisture from the Gulf of Mexico arrived over the northern Great Plains at the same time as a strong southerly flow developed over the Dakotas and Saskatchewan, Canada, in advance of the deepening cutoff low over Alberta. This moist air was then transported northward over Saskatchewan and finally westward over the southern Mackenzie River basin, where strong ascent occurred.
Seasonal Variations of Precipitation Properties Associated with the Monsoon over Palau in the Western Pacific
Authors: Kubota Hisayuki , Shirooka Ryuichi , Ushiyama Tomoki , Chuda Takashi , Iwasaki Suginori , Takeuchi Kensuke
Published: September 2005

In this study, the authors focused on the seasonal variations of precipitation properties over the western Pacific, particularly those associated with the wind direction of the monsoon. An observational project over Peleliu Island in the Republic of Palau was carried out, and data on precipitation, equivalent cloud amount, and precipitable water were collected from 28 June 2001 to 30 April 2002. First, the monsoon season over Palau was defined as a period with 850-hPa zonal-wind sounding data with sustained winds exceeding 5 m s−1. The westerly wind regime continued until 25 November 2001, and the next westerly wind regime began on 18 May 2002. The equivalent cloud amount increased during the period when the westerly wind intensified. The precipitation had a diurnal variation in the active phase of the westerly wind regime, increasing from nighttime to early morning and decreasing in the afternoon. The diurnal variation was weak in the inactive phase and had a lesser afternoon maximum. Precipitation intensity was high and its duration was short during the westerly wind regime.

The precipitable water decreased during the easterly wind regime when a dry period appeared, and precipitation was also suppressed during those days. However, there was little difference between the precipitation amounts of the westerly and easterly wind regimes. The equivalent cloud amount did not decrease as the zonal-wind direction changed to easterlies during the easterly wind regime. The authors noticed no diurnal variation of precipitation during the easterly wind regime. These differences in the precipitation properties during westerlies and easterlies may be related to the seasonal variation of humidity in the environment.
Hydrological Validation of a Radar-Based Nowcasting Technique
Authors: Berenguer Marc , Corral Carles , Sánchez-Diezma Rafael , Sempere-Torres Daniel
Published: September 2005

Nowcasting precipitation is a key element in the anticipation of floods in warning systems. In this framework, weather radars are very useful because of the high resolution of their measurements both in time and space. The aim of this study is to assess the performance of a recently proposed nowcasting technique (S-PROG) from a hydrological point of view in a Mediterranean environment. S-PROG is based on the advection of weather radar fields according to the motion field derived with an algorithm based on tracking radar echoes by correlation (TREC), and it has the ability of filtering out the most unpredictable scales of these fields as the forecasting time increases. Validation of this nowcasting technique was done from two different perspectives: (i) comparing forecasted precipitation fields against radar measurements, and (ii) by means of a distributed rainfall runoff model, comparing hydrographs simulated with a hydrological model using rainfall fields forecasted by S-PROG against hydrographs generated with the model using the entire series of radar measurements. In both cases, results obtained by a simpler nowcasting technique are used as a reference to evaluate improvements. Validation showed that precipitation fields forecasted with S-PROG seem to be better than fields forecasted using simpler techniques. Additionally, hydrological validation led the authors to point out that the use of radar-based nowcasting techniques allows the anticipation window in which flow estimates are forecasted with enough quality to be sensibly extended.
Explaining the Rise and Fall of Military Regimes: Civil-Military Relations in the Congo
Authors: Emizet Kisangani N. F.
Published: October 2005

The primary argument of this article is that the disintegration of the military is a function of circumstances generated within civil-military relations. This argument seems to undermine Samuel Huntington's military subordination through either subjective or objective controls. In looking at the Congolese situation, this analysis relies on Morris Janowitz's idea of a politicized military corps to understand the rise and fall of General Mobutu Sese Seko. Janowitz's suggestion that the military is becoming more politicized, regardless of its level of professionalism, properly represents events in the Congo under General Mobutu. In fact, it was this high level of politicization that over time led to Mobutu's downfall. Using Janowitz's typology of the military in developing countries, this article focuses on several factors that explain why the military might fail to perform effectively in its mission of defending the state. Among these conditions are colonial legacy, economic survival, frequent military purges and reshuffling of top officers, regimental segmentation, poor recruiting and training programs, promotion of officers on the basis of subnational loyalty rather than combat experience, and the withdrawal of support from powerful patron states.
Psychological Propaganda: The War of Ideas on Ideas During the First Half of the Twentieth Century
Authors: Finch Lyneyve
Published: October 2005

Explaining why propaganda has become such an important feature of modem warfare is the main task of this article. It explores a shift, dating from the late nineteenth century, when wars fought by mercenary armies were replaced by total warfare, fought by entire populations, and explains why this shift made propaganda a crucial component of modem warfare. The necessity of enlisting the entire civilian population, along with the quest to have that population react to what Walter Lippmann called the "pseudo-environment" of a propaganda war, is similarly outlined. By exploring the origins of psychological warfare up to, and including, the Second World War, the article provides the background for contemporary wars, in which propaganda dominates war reporting. The psychological significance of reporting and attributing blame for atrocities is also explained, and suggests connections to contemporary war reporting, which prioritizes, not war tactics and loss of military equipment and life, but reports of outrages against civilians.
General John Shalikashvili and the Civil-Military Relations of Peacekeeping
Authors: Goldstein Lyle J.
Published: October 2005

The American officer corps has adopted the post-Cold War peacekeeping mission with considerable reluctance. This reluctance was clearly manifested in the person of General Colin Powell, who overstepped traditional American civil-military norms in leveraging his extensive political clout against U.S. involvement in peacekeeping efforts. This and other factors led many observers to conclude that American civil-military relations were in crisis.

Powell's successor, General John Shalikashvili, who retired in September 1997, did much to restore a working balance to American civil-military relations. He understood that Powell's sweeping skepticism about peacekeeping exceeded the profesional competence of the military officer. Shalikashvili did not take the position that peacekeeping was either wholly worthy or wholly worthless, but examined each case from Rwanda to Bosnia on its own merits. No yes-man for the Clinton administration, he frequently injected caution into deliberations. His professional demeanor helped make American foreign policy more effective by improving the quality of military advice given to the president.
Why Don't Minorities Join Special Operations Forces?
Authors: Kirby Sheila Nataraj , Harrell Margaret C. , Sloan Jennifer
Published: October 2005

Following the Cold War, regional instability and lower-level conflict have increased, bringing with them enhanced roles and responsibilities for the U.S. Special Operations Forces (SOF). As a result, ensuring and maintaining the personnel readiness of the SOF is critical. One of the major issues facing SOF is recruiting and ensuring ethnic diversity among its members. This study examines the racial and ethnic composition of SOF operators, and the barriers that stand in the way of recruiting minorities. It identifies both structural and perceptual barriers to minority participation and also examines the question of minorities' lack of interest in SOF as a career. Its methodology and findings should be of interest to other agencies and firms dealing with issues of minority representation.
Nationalism, National Security, and Amazônia: Military Perceptions and Attitudes in Contemporary Brazil
Authors: Filho João R. Martins , Zirker Daniel
Published: October 2005

The end of the Cold War had profoundly affected Brazilian military thought, and, consequently, military planning and development, by the late 1990s. Recent evidence suggests that the Brazilian military is increasingly concerned with threats to national sovereignty putatively posed by international organizations, nongovernmental organizations (NGOs), and the most industrialized countries. Moreover, the Brazilian military sees such threats as likely to be clothed in the guise of "idealistic" concerns, including the protection of aboriginal (and other human) rights, and the protection of the environment.

The traditional military preoccupation with the Brazilian Amaz6nia has clearly been intensified by these perceptions. While low-intensity conflict with traffickers in contraband and with guerrillas remains a central concern in military planning for the region, there is increasing discussion by key military officers of larger threats. Reinforced by NATO's attack on Yugoslavia, a new, post-Cold War era in Brazilian military thought appears to be taking shape, one in which defense against direct threats to national sovereignty, principally in the vast Amazon region, has become a central tenet. Brazil's new "Policy for National Defense," and its creation of a civilian-led Ministry of Defense, should be seen in this new context.
Army Officers' Spouses: Have the White Gloves Been Mothballed?
Authors: Harrell Margaret C.
Published: October 2005

This article is an in-depth ethnographic assessment of the role expectations for military spouses. In the late 1980s, the Department of Defense acknowledged the rights of military spouses to pursue their own careers and ruled that the attitudes and behaviors of officers' spouses would not be considered a factor in officer promotions or assignments. Given this policy and the increasing societal acceptance of female participation in the paid labor force, as well as increased diversity among military families, the present study hypothesized a decrease in formal expectations for officers' wives. The article discusses evidence that formal expectations for some officers' wives have actually increased, and that wives' performance and adherence to expected military role behavior is once again a feature of the officer evaluation process. The conclusions and policy implications indicate that the pressures placed upon officer spouses negatively impact readiness and retention.
Post-Communist Civil-Military Reform in Poland and Hungary: Progress and Problems
Authors: Yaniszewski Mark
Published: October 2005

This article critically analyzes post-Communist Polish and Hungarian civil-military reforms in the context of five issues: (1) the dismantling of Communist-era control mechanisms; (2) the establishment of clear and constitutionally-guaranteed lines of civilian authority; (3) the enactment of necessary legislation, rules, and regulations to put into effect a system of democratic oversight; (4) the reorganization of military structures; and (5) the provision of sufficient resources for military reform and operations. Although both states were sufficiently reformed to allow for their ascension to the NATO alliance in early 1999, this study comes to a more positive overall assessment of Poland's reform efforts because most key civil-military reforms have either been completed or are moving (albeit sometimes quite slowly) in a positive direction. In the case of Hungary, significant progress has also occurred, but the reform program-which got off to a fast start has slowed considerably and may be threatened with reverses by a severe budgetary and procurement crisis that shows few (if any) signs of improving.
How Not to Institutionalize Civilian Control: Kenya's Coup Prevention Strategies, 1964-1997
Authors: N'Diaye Boubacar
Published: October 2005

Kenya is on the short list of African states that have not experienced military rule. In a continent known for rampant praetorianism, this means only that the coup prevention strategies implemented by its civilian rulers have been successful...so far. The unscrupulous ethnic manipulation, politicization, bribery into the military's "circles of power," and the set-up of a powerful paramilitary as a counterweight to the army have done little to institutionalize civilian control. These strategies, inaugurated by President Jomo Kenyatta and taken to new heights by his successor Daniel Arap Moi, entailed neither military professionalization, military autonomy and political insulation, nor regime-legitimizing policies. The evidence of the case study suggests that the adverse effects of Kenya's civilian control strategies support Samuel Huntington's and Claude Welch Jr.'s hypothesis that only the professionalization and political insulation of the military are more likely to ensure its continued subordination to civilian control. The strategies implemented since independence epitomize the model of civil-military relations that Africa's fledgling democracies should avoid if democratic civilian control of the military is to take root on the continent.
Warfare and Welfare: Military Service, Combat, and Marital Dissolution
Authors: Ruger William , Wilson Sven E. , Waddoups Shawn L.
Published: October 2005

This article investigates the impact of military service on the duration of a veteran's first marriage, a topic in the literature with both scant and highly contradictory conclusions. Our sample consisted of 3,800 males from the National Survey of Families and Households (1987-1994). Using hazard rate analysis, we estimate the impact of both combat and noncombat assignments on marital duration. Our statistical results imply: (1) self-reported participation in combat increases the hazard rate for marital dissolution by over 60 percent; (2) time of marriage (whether before, during, or after the war) does not affect dissolution, except for wartime marriages during WWII, where the effect is strong; and (3) the effects of war differ significantly across the major U.S. wars; surprisingly, the strongest negative impact on duration occurs with the neglected Korean War veterans.