State dependence

Although several studies have assessed the relationships between the temperament dimensions of the Cloninger model of personality and depression\ little is known about the role played by the character dimensions proposed by the seven!factor model of Cloninger in depression[ In this study\ the relationships between the Temperament and Character Inventory "TCI# and depression were examined in a sample of 39 major depressive patients and 39 healthy controls[ Depressed patients exhibit higher harm avoidance and self!transcendence scores as well as lower self!directedness and cooperativeness scores as compared to healthy controls[ However\ the three other dimensions do not di}er between depressive patients and controls[ Among the depressive group\ harm avoidance\ self!directedness and cooperativeness dimensions are related to the severity of depression as assessed by the Hamilton scale[ This study con_rms the state dependence of the harm avoidance dimension and suggests a relationship between the character dimensions of the Cloninger model and depression[ Þ 0888 Elsevier Science Ltd[ All rights reserved[

This article describes the development and reliability and validity testing of the Addiction Severity Assessment Tool (ASAT), a brief, 27-item multidimensional self-report measure of problem severity in daily functioning, relational functioning, dysphoric states, dependence severity, recovery skill/self-efficacy, and existential factors for adult substance abuse clients. Items generated for an Alpha version were conceptually and empirically evaluated. A Beta version underwent further empirical evaluation and item selection. Cross validation of the final version examined internal consistency, test-retest reliability, factor structure, and convergent/discriminant and known groups validity. Sensitivity to change was evaluated in a 3-month outcome study. Clients were recruited from inpatient, outpatient and residential substance abuse treatment centers, and a sample of 238 nonpatients were also recruited from community groups. The Beta version was tested with 201 clients, and cross validation involved 242 clients. Well-known standardized, self-report and interview-based comparison measures were used to test convergent/discriminant validity of the ASAT. Reliability coefficients for the six ASAT domains were acceptable. Reasonable convergent/discriminant and known groups, construct validity were demonstrated, along with sensitivity to change of the domain scale scores. The ASAT appears to comprise a useful new tool for assessing clinical outcomes of adult clients in substance abuse treatment.

We use a discrete-time dynamic multinomial logit model with …xed e¤ects to study the port of entry versus trap hypotheses of temporary contracts in Italy. The WHIP data allows us to observe several kinds of temporary contracts and to distinguish between contract transformations occurring within the same …rm and job changes across di¤erent employers. After controlling for contract sorting due to workers' unobserved heterogeneity, we …nd evidence of state dependence in the form of: (i) contract persistence: whatever the initial state of a worker, retaining the same contract is always the most likely outcome; (ii) port of entry: the transition to open ended employment is more likely for individuals holding any type of temporary contracts than for the unemployed; (iii) yet, not all temporary contracts are the same: training contracts are the best port of entry, while quasi-subordinate work is the worst. (iv) When controlling for transitions within or between …rms it emerges that the port of entry is observed mainly within the same …rm, where a long cursus honorum from temporary to open ended contracts comes to light. Long-lasting open ended jobs are the only port of entry across …rms.

Background: To determine whether significant symptoms of inattention were present among the offspring of wellcharacterized bipolar parents. Methods: We included 53 offspring of 30 parents meeting DSM-IV criteria for bipolar disorder diagnosed by consensus on the basis of a SADS-L interview and a wealth of longitudinal clinical data. The unaffected parent had no lifetime history of a major psychiatric illness. Offspring, prospectively followed for up to 5 years, completed psychometric measures of attention and mood when judged to be at a good level of functioning (well, remitted or treated). Results: Those offspring with any lifetime psychiatric diagnosis endorsed more subjective problems with attention. However, there was no measurable difference on tasks of sustained attention between those with and those without a lifetime psychiatric illness including affective disorder. There was a significant association between self-reported symptoms of depression and inattention, but no association between either self-report measure and an objective measure of sustained attention. Limitations: This study was not intended to be a comprehensive neuropsychological investigation of at risk offspring. Conclusions: In this high-risk population, subjective difficulty with attention appeared to be state-dependent, associated with the degree of subjective distress related to an underlying psychiatric illness.

The effects on the structural and functional properties of the Kv1.2 voltage-gated ion channel, caused by selective mutation of voltage sensor domain residues, have been investigated using classical molecular dynamics simulations. Following experiments that have identified mutations of voltage-gated ion channels involved in state-dependent omega currents, we observe for both the open and closed conformations of the Kv1.2 that specific mutations of S4 gating-charge residues destabilize the electrostatic network between helices of the voltage sensor domain, resulting in the formation of hydrophilic pathways linking the intra-and extracellular media. When such mutant channels are subject to transmembrane potentials, they conduct cations via these so-called ''omega pores.'' This study provides therefore further insight into the molecular mechanisms that lead to omega currents, which have been linked to certain channelopathies.

GDP-4-keto-6-deoxy-D-mannose epimerase/reductase is a bifunctional enzyme responsible for the last step in the biosynthesis of GDP-L-fucose, the substrate of fucosyl transferases. Several cell-surface antigens, including the leukocyte Lewis system and cell-surface antigens in pathogenic bacteria, depend on the availability of GDP-L-fucose for their expression. Therefore, the enzyme is a potential target for therapy in pathological states depending on selectin-mediated cell-to-cell interactions. Previous crystallographic investigations have shown that GDP-4-keto-6-deoxy-Dmannose epimerase/reductase belongs to the short-chain dehydrogenase/reductase protein homology family. The enzyme active-site region is at the interface of an N-terminal NADPH-binding domain and a C-terminal domain, held to bind the substrate. The design, expression and functional characterization of seven site-speci®c mutant forms of GDP-4-keto-6-deoxy-D-mannose epimerase/reductase are reported here. In parallel, the crystal structures of the native holoenzyme and of three mutants (Ser107Ala, Tyr136Glu and Lys140Arg) have been investigated and re®ned at 1.45-1.60 A Ê resolution, based on synchrotron data (R-factors range between 12.6 % and 13.9 %). The re®ned protein models show that besides the active-site residues Ser107, Tyr136 and Lys140, whose mutations impair the overall enzymatic activity and may affect the coenzyme binding mode, side-chains capable of proton exchange, located around the expected substrate (GDP-4-keto-6-deoxy-D-mannose) binding pocket, are selectively required during the epimerization and reduction steps. Among these, Cys109 and His179 may play a primary role in proton exchange between the enzyme and the epimerization catalytic intermediates. Finally, the additional role of mutated active-site residues involved in substrate recognition and in enzyme stability has been analyzed.

This paper is devoted to the design and construction of a novel technique for ferrite tuning of dielectric loaded, dual-mode cavity filters. This is dealt with in two specific areas: i) Improving the technique to realize a high -Q , low loss, dielectric-loaded, dual-mode cavity band-pass filter, using the hybrid 11 HEM δ mode, ii) Developing techniques to obtain a wide range tuning mechanism, using ferrite materials. The designed dual-mode filters offer unloaded u Q of more than 10,000 with an insertion loss less than 1 dB. It is shown that ferrite tuning is possible either at below resonance or at the above resonance state, depending upon the strength of the applied DC magnetic field. Experimental results showed that due to its lower saturation magnetization YIG offers a wider tuning range compared with Nickel ferrite.

In this paper we develop a framework for the study of financial equilibrium in the case of sectors in the economy, each of which is faced with two objectives/criteria in his portfolio selection decision making. In particular, we first present the bicriteria decision model of an individual financial sector, who seeks an optimal portfolio composition, given that the wishes to

Event-related brain potentials (ERPs) were used to examine whether the processing of food pictures is selectively modulated by changes in the motivational state of the observer. Sixteen healthy male volunteers were tested twice 1 week apart, either after 24 hr of food deprivation or after normal food intake. ERPs were measured while participants viewed appetitive food pictures as well as standard emotional and neutral control pictures. Results show that the ERPs to food pictures in a hungry, rather than satiated, state were associated with enlarged positive potentials over posterior sensor sites in a time window of 170 -310 ms poststimulus. Minimum-norm analysis suggests the enhanced processing of food cues primarily in occipito-temporo-parietal regions. In contrast, processing of standard emotional and neutral pictures was not modulated by food deprivation. Considered from the perspective of motivated attention, the selective change of food cue processing may reflect a state-dependent change in stimulus salience.

In this paper we consider a one-warehouse N-retailer inventory system characterized by access to realtime point-of-sale data, and a time based dispatching and shipment consolidation policy at the warehouse. More precisely, inventory is reviewed continuously, while a consolidated shipment (for example, a truck) to all retailers is dispatched from the warehouse at regular time intervals. The focus is on investigating the cost benefits of using state-dependent myopic allocation policies instead of a simple FCFS (First-Come-First-Serve) rule to allocate shipped goods to the retailers. The analysis aims to shed some light on when, if ever, FCFS is a reasonable policy to use in this type of system? The FCFS allocations of items to retailers are determined by the sequence in which retailer orders (or equivalently customer demands) arrive to the warehouse. Applying the myopic policy enables the warehouse to postpone the allocation decision to the moment of shipment (from the warehouse) or the moments of delivery (to the different retailers), and to base it on the inventory information available at those times. The myopic allocation method we study is often used in the literature on periodic review systems.

We propose a new scheme for a flux/phase qubit, based on a double-SQUID modified to achieve a direct readout of the flux state. The readout is performed by inserting a large Josephson junction in the SQUID loop; the junction is biased by an external current and switches from the zero-voltage to the running state depending on the flux state of the qubit. We report recent results concerning the theoretical behavior and the experimental characterization at 4.2 K of the device, which has been realized with Nb/AlOx/Nb trilayer technology.

Diagnosis classifies the present state of operation of the equipment, and prognosis predicts the next state of operation and its remaining useful life. In this paper, a prognosis method for the gear faults in dc machines is presented. The proposed method uses the time-frequency features extracted from the motor current as machine health indicators and predicts the future state of fault severity using hidden Markov models (HMMs). Parameter training of HMMs generally needs huge historical data, which are often not available in the case of electrical machines. Methods for computing the parameters from limited data are presented. The proposed prognosis method uses matching pursuit decomposition for estimating state-transition probabilities and experimental observations for computing state-dependent observation probability distributions. The proposed method is illustrated by examples using data collected from the experimental setup.

This paper develops a framework for analysing and calculating system optimizing flow and externalities in time-dependent road networks. The externalities are derived by using a novel sensitivity analysis of traffic models. The optimal network flow is determined by solving a state-dependent optimal control problem, which assigns traffic such that the total system cost of the network system is minimized. This control theoretic formulation can work with general travel time models and cost functions. Deterministic queue is predominantly used in dynamic network models. The analysis in this paper is more general and is applied to calculate the system optimizing flow for Friesz's whole link traffic model. Numerical examples are provided for illustration and discussion. Finally, some concluding remarks are given.

In this paper we consider the infinite dimensional variational inequality (VI) formulation of dynamic user equilibrium (DUE) put forward by Friesz et al [1] as well as the differential variational inequality (DVI) version reported in Friesz et al . We show how the theory of optimal control and the theory of infinite dimensional variational inequalities may be combined to create a simple and effective fixed point algorithm for calculating DUE network flows that are solutions of both formulations. A numerical example is provided.

This paper advocates a strict compositional and hybrid approach for obtaining key (performance) metrics of embedded systems. At its core the developed methodology abstracts system components by either flow-oriented and purely analytic descriptions or by state-based models in the form of timed automata. The interaction among the heterogeneous components is modeled by streams of discrete activitytriggers. In total this yields a hybrid framework for the compositional analysis of embedded systems. It supplements contemporary techniques for the following reasons: (a) state space explosion as intrinsic to formal verification is limited to the level of isolated components; (b) computed performance metrics such as buffer sizes, delays and utilization rates are not overly pessimistic, because coarse-grained purely analytic models are used for components only which conform to the stateless model of computation. For demonstrating the usefulness of the presented ideas we implemented a corresponding tool-chain and investigated the performance of a two-staged computing system, where one stage exhibits state-dependent behavior only coarsely coverable by a purely analytic and stateless component abstraction.

Pressure-electric ͑hydrostatic piezoelectric͒ measurements are reported on bookshelf textures of a ferroelectric smectic-C (Sm C*) liquid crystal with a glass transition. The continuous variation of a partially fluid state to the solid glass enables one to trace how the piezoelectric effect depends on the consistency of the material. It was observed that in the Sm C* samples with poled glass the piezoelectric constants are comparable to conventional piezoelectric crystals and poled piezoelectric polymers. This implies their application possibilities. The magnitude of the piezoelectric constant in the glassy state depends very much on the poling conditions. The studies indicate that there are two counteracting effects, which cancel each other out in the Sm C* phase near the glass transition. Our analysis indicates that the pressure-induced director tilt change has a dominating effect both in the fluid and the glassy Sm C* states.

The importance of parental education and living conditions on children's educational attainment is quantified. Two estimation strategies are followed: the least squares estimation uses number of years of education as the dependent variable, and the "double probit"-model with endogenous selection uses a two class categorisation of education. It is found, that parents' education, and especially mother's education, matters for children's

In today's tight, competitive, and volatile market in semiconductor manufacturing, a successful semiconductor manufacturer has to look into multiple performance indices such as cycle time and on-time delivery. Effective dispatching mechanism is a widely used strategy to achieve these performance indices simultaneously. In the past, dispatching studies in semiconductor manufacturing have primarily focused on the level of tool dispatching. This

We consider stochastic discrete-time systems with multiplicative noise which are controlled by dynamic output feedback and subjected to blockdiagonal stochastic parameter perturbations. Stability radii for these systems are characterized via scaling techniques and it is shown that for real data, the real and the complex stability radii coincide. In a second part of the paper we investigate the problem of maximizing the stability radii by dynamic output feedback. Necessary and su cient conditions are derived for the existence of a stabilizing compensator which ensures that the stability radius is above a prespeci ed level. These conditions consist of parametrized matrix inequalities and a coupling condition.

A state-dependent learning paradigm was used in which subjects encoded and recalled equivalent lists of conceptually categorized words m each of the following conditions: (a) encode following administration of a marijuana placebo-recaU placebo, (b) encode placebo-recall following administration of active marijuana, (c) encode marijuana-recall marijuana, and (d) encode marijuana-recall placebo. Free recall of both words and categories was more complete in the encode marijuana-recall marijuana condition than in the encode marijuana-recall placebo condition, a finding indicative of asymmetric state-dependent learning. However, these differences were not apparent when recall was prompted with appropriate extralist retrieval cues. It was concluded that the accesslbihty of retrieval cues which provide access to higher-order memory umts which have been encoded in the dissociated state depends on restoration of that state at the time of attempted recall. Several implications of this reasoning for future stu&es of the cognitive mechanism underlying human state-dependence were considered. Special thanks are due Dr. Endel Tulving for his helpful comments on numerous theoretical and methodological issues The assistance provided by Drs.

We consider a fluid queue driven by a discouraged arrivals queue and obtain explicit expressions for the stationary distribution function of the buffer content in terms of confluent hypergeometric functions. We compare it with a fluid queue driven by an infinite server queue. Numerical results are presented to compare the behaviour of the buffer content distributions for both these models.

The state-dependent theory of the relationship between affective states and memory holds that recall will be best when the affective state at recall matches that during learning. Sequential happy, neutral, and sad affective states that were either consistent (e.g., Happy-Happy) or inconsistent (e.g., Sad-Neutral) were experimentally induced in preschool children prior to encoding and then again prior to retrieval (free

We have considered a wide array of scenarios for Europa's chemical evolution in an attempt to explain the presence of ice and hydrated materials on its surface and to understand the physical and chemical nature of any ocean that may lie below. We postulate that, following formation of the jovian system, the europan evolutionary sequence has as its major links: (a) initial carbonaceous chondrite rock, (b) global primordial aqueous differentiation and formation of an impure primordial hydrous crust, (c) brine evolution and intracrustal differentiation, (d) degassing of Europa's mantle and gas venting, (e) hydrothermal processes, and (f) chemical surface alteration. Our models were developed in the context of constraints provided by Galileo imaging, near infrared reflectance spectroscopy, and gravity and magnetometer data. Low-temperature aqueous differentiation from a carbonaceous CI or CM chondrite precursor, without further chemical processing, would result in a crust/ocean enriched in magnesium sulfate and sodium sulfate, consistent with Galileo spectroscopy. Within the bounds of this simple model, a wide range of possible layered structures may result; the final state depends on the details of intracrustal differentiation. Devolatilization of the rocky mantle and hydrothermal brine reactions could have produced very different ocean/crust compositions, e.g., an ocean/crust of sodium carbonate or sulfuric acid, or a crust containing abundant clathrate hydrates. Realistic chemical-physical evolution scenarios differ greatly in detailed predictions, but they generally call for a highly impure and chemically layered crust. Some of these models could lead also to lateral chemical heterogeneities by diapiric upwellings and/or cryovolcanism. We describe some plausible geological consequences of the physical-chemical structures predicted from these scenarios. These predicted consequences and observed aspects of Europa's geology may serve as a basis for further analys is and discrimination among several alternative scenarios. Most chemical pathways could support viable ecosystems based on analogy with the metabolic and physiological versatility of terrestrial microorganisms.

AbstractÐAnalyses of scalp-recorded sleep spindles have demonstrated topographically distinct slow and fast spindle waves. In the present paper, the electrical activity in the brain corresponding to different types of sleep spindles was estimated by means of low-resolution electromagnetic tomography. In its new implementation, this method is based on realistic head geometry and solution space is restricted to the cortical gray matter and hippocampus. In multichannel allnight electroencephalographic recordings, 10±20 artifact-free 1.25-s epochs with frontally, parietally and approximately equally distributed spindles were marked visually in 10 normal healthy subjects aged 20±35 years. As a control condition, artifact-free non-spindle epochs 1±3 s before or after the corresponding spindle episodes were marked. Low-resolution electromagnetic tomography demonstrated, independent of the scalp distribution, a distributed spindle source in the prefrontal cortex (Brodmann areas 9 and 10), oscillating with a frequency below 13 Hz, and in the precuneus (Brodmann area 7), oscillating with a frequency above 13 Hz. In extremely rare cases only the prefrontal or the parietal source was active. Brodmann areas 9 and 10 have principal connections to the dorsomedial thalamic nucleus; Brodmann area 7 is connected to the lateroposterior, laterodorsal and rostral intralaminar centrolateral thalamic nuclei. Thus, the localized cortical brain regions are directly connected with adjacent parts of the dorsal thalamus, where sleep spindles are generated.

Among the factors which could explain avoidance behavior toward dental care, the typical clinging odor of the dental office, due to eugenol, is investigated in this study. The hypothesis is supported by the well-known effects of odorants which may influence cognition, emotion, and behavior. The aisociation between the odor of eugenol and dental fear and anxiety could be explained by the fact that eugenates (eugenol-containing cements) are often used in potentially painful restorative dentistry on vital teeth. The emotional impact of the odors of eugenol and two other dental products (menthol and methyl methacrylate) was evaluated on volunteer subjects through autonomic nervous system (ANS) analysis by recording the variations of six ANS parameters (two electrodermal, two thermovascular, and two cardiorespiratory) induced by the inhalation of the odorants. After the experiment, subjects were asked to fill out an 11-point hedonic scale to rate the pleasantness vs. unpleasantness for each odorant. Results were compared between two groups of subjects divided according to their own dental experience (fearful and non-fearful dental-care subjects). These showed that, in both groups, menthol was rated as pleasant and methyl methacrylate as very unpleasant, whereas eugenol was judged pleasant by nonfearful subjects but unpleasant by fearful subjects. Concerning autonomic analysis, only eugenol induced significantly different patterns of ANS responses between the two groups, with stronger variations for dentally fearful subjects, mainly observed through the electrodermal channel. These results suggest that eugenol can be responsible for different emotional states, depending on the unpleasantness of the subjects' dental experience. This seems to confirm the role of odors as elicitors of emotional memories and to support the possible influence of eugenol odor on the avoidance behavior of some subjects toward dental care.

Steady state absorption and uorescence as well as the time resolved absorption studies in the pico and subpicosecond time domain have been performed to characterize the excited singlet and triplet states of Michler's ketone (MK). The nature of the lowest excited singlet (S 1 ) and triplet (T 1 ) states depends on the polarity of the solvent -in nonpolar solvents they have either pure n¼ ¤ character or mixed character of n¼ ¤ and ¼ ¼ ¤ states but in more polar solvents the states have CT character. Concentration dependence of the shapes of the uorescence as well the excited singlet and triplet absorption spectra provide the evidence for the association of the MK molecules in the ground state.

The loss of submerged macrophytes during eutrophication of shallow lakes is a commonly observed phenomenon. The proximate reason for this decline is a reduction of available light due to increasing phytoplankton and/or epiphyton biomass. Here we argue that the ultimate cause for the transition from a macrophyte-dominated state to a phytoplankton-dominated state is a change in fish community structure. A catastrophic disturbance event (e.g. winterkill) acting selectively on piscivores, cascades down food chains, eventually reducing macrophyte growth through shading by epiphyton, an effect that is reinforced by increasing phytoplankton biomass. The transition back from the phytoplankton to the macrophyte state depends on an increase in piscivore standing stock and a reduction of planktivores. A conceptual model of these mechanisms is presented and supported by literature data and preliminary observations from a field experiment.

Type R (Pt-13 %Rh versus Pt) and type S (Pt-10 %Rh versus Pt) thermocouples are widely used as reference and working standards for temperature measurements both in calibration laboratories and in industry for temperatures up to 1600 • C. Many laboratories claim that the best achievable uncertainty is 0.1 • C up to 1000 • C and 0.3 • C up to 1550 • C, and international comparisons confirm that this is achievable practically. However, due to (i) preferential Rh oxidation of the Pt-Rh alloy thermoelement and (ii) defect quenching effects, these thermocouples suffer from reversible hysteresis in their calibration. As a result, calibration laboratories usually perform some heat treatment of the wire prior to calibration to attain a specific 'annealing state', at which the calibration is performed. Internationally, there are two commonly used annealing states for these thermocouples: the '450 • C annealed state' and the '1100 • C quenched state'. High-level comparisons between laboratories in the calibration of type R or type S thermocouples will rigorously specify the annealing state in the protocol, so any systematic differences due to the choice of annealing state will be masked. This article compares the calibration of several thermocouples using the two common annealing states, finding that the difference can be as large as 0.2 • C at 961 • C, larger than the best calibration uncertainties reported. The article examines the advantages and disadvantages to the user of calibrations performed in each state, and the implications for the uncertainty analysis for calibration and use of type R and type S thermocouples.

Information flow in a telecommunication network is accomplished through the interaction of mechanisms at various design layers with the end goal of supporting the information exchange needs of the applications. In wireless networks in particular, the different layers interact in a nontrivial manner in order to support information transfer. In this text we will present abstract models that capture the cross-layer interaction from the physical to transport layer in wireless network architectures including cellular, ad-hoc and sensor networks as well as hybrid wireless-wireline. The model allows for arbitrary network topologies as well as traffic forwarding modes, including datagrams and virtual circuits. Furthermore the time varying nature of a wireless network, due either to fading channels or to changing connectivity due to mobility, is adequately captured in our model to allow for state dependent network control policies. Quantitative performance measures that capture the quality of service requirements in these systems depending on the supported applications are discussed, including throughput maximization, energy consumption minimization, rate utility function maximization as well as general performance functionals. Cross-layer control algorithms with optimal or suboptimal performance with respect to the above measures are presented and analyzed. A detailed exposition of the related analysis and design techniques is provided.

Transcranial magnetic stimulation (TMS) has become a mainstay of cognitive neuroscience, thus facing new challenges due to its widespread application on behaviorally silent areas. In this review we will summarize the main technical and methodological considerations that are necessary when using TMS in cognitive neuroscience, based on a corpus of studies and technical improvements that has become available in most recent years. Although TMS has been applied only relatively recently on a large scale to the study of higher functions, a range of protocols that elucidate how this technique can be used to investigate a variety of issues is already available, such as single pulse, paired pulse, dual-site, repetitive and theta burst TMS. Finally, we will touch on recent promising approaches that provide powerful new insights about causal interactions among brain regions (i.e., TMS with other neuroimaging techniques) and will enable researchers to enhance the functional resolution of TMS (i....

Although several studies have assessed the relationships between the temperament dimensions of the Cloninger model of personality and depression, little is known about the role played by the character dimensions proposed by the seven-factor model of Cloninger in depression. In this study, the relationships between the Temperament and Character Inventory (TCI) and depression were examined in a sample of 40 major depressive patients and 40 healthy controls. Depressed patients exhibit higher harm avoidance and self-transcendence scores as well as lower self-directedness and cooperativeness scores as compared to healthy controls. However, the three other dimensions do not differ between depressive patients and controls. Among the depressive group, harm avoidance, self-directedness and cooperativeness dimensions are related to the severity of depression as assessed by the Hamilton scale. This study confirms the state dependence of the harm avoidance dimension and suggests a relationship between the character dimensions of the Cloninger model and depression.

Criminological research has consistently uncovered a positive correlationbetween past and current criminal behavior. Continuity in offending overtime can be attributed to at least two processes—populationheterogeneity and state dependence. A population heterogeneity processattributes stability in offending over time to differences in ananti-social characteristic (self-control, impulsivity, psychopathicpersonality) across persons that is established early in life andtime-stable thereafter. An implication of a population heterogeneityexplanation for continuity in offending over time is that the anti-socialcharacteristic is likely to have reverberations throughout life, takingmany manifestations later in life (unemployment, drug addiction, maritalinstability). Any observed correlation between these later life events andcriminality, therefore, is spurious rather than causal, due to the factthat they are all the effects of a common cause. A state dependenceexplanation, in contrast, attributes observed stability in criminaloffending to a process of contagion. That is, criminal behavior has agenuine causal effect on subsequent criminality by eroding constraintsand strengthening incentives to crime. The implication of a statedependence process is that criminal conduct may be influenced by laterlife events. In this paper, we draw a connection between populationheterogeneity and state dependence processes and extant criminologicaltheory. We also review the literature that has investigated theplausibility of these two processes. Finally, concluding that weknow very little about them we make recommendations for future researchon population heterogeneity and state dependence.

The defining characteristic of addiction is compulsive, out-of-control drug use despite serious negative consequences. The life of an addicted person becomes progressively focused on obtaining, using and recovering from the effects of drugs, despite illness, disrupted relationships and failures in life roles 1,2 . For example, we know of a physician who, despite extensive vascular surgery and threatened amputations, continues to smoke cigarettes; many clinicians have seen individuals who attempt to smoke through a tracheotomy tube after a laryngectomy for cancer; and, despite loss of employment and life-threatening complications of cirrhosis, many people continue to drink alcohol even when drinking yields depression rather than pleasure. These examples highlight the central question of addiction: what happens in the brain to cause an addicted person to lose control of drug-taking behaviour even when experiencing serious drug-related harm?

Cr catalysts supported on silica, zeolite NaY, and charcoal were prepared with two different methods. They were characterized and examined in the polymerization of ethene. Cyclic voltammetry, electron spin resonance, X-ray photoelectron spectroscopy and silicon-29 magic-angle spinning nuclear magnetic resonance spectroscopy were used to characterize them, demonstrating that Cr is not in a single oxidation state, that the distribution among the various oxidation states depends on the history of the sample, and that even for a single oxidation state a variety of different environments can occur. In the polymerization of ethene, the supported Cr catalysts exhibited activity values varying from 10 3 to 10 5 gPE ⅐ molCr Ϫ1 ⅐ [M] Ϫ1 ⅐ h Ϫ1 , depending on the choice of the support and on the method by which the Cr is placed on it. Silica seemed to be the most efficient support for Cr for this reaction. However, the zeolite-supported catalysts also showed reasonable activity values (A p Х 10 4 units) and presented the advantage of having a strong interaction between the Cr and the support, which may prevent leaching of the cation into the surrounding environment.

Burning embers, commonly called firebrands, are lofted by a fire's buoyant plume and transported downwind to ignite new fires (spot fires) ahead of the main fire. In the present work, transport and combustion of firebrands from burning trees are numerically investigated. A three-dimensional physics-based model is used to precompute the steady-state gas flow and thermal fields induced by a crown fire into which firebrands will be injected. Another preliminary study of the thermal degradation and combustion of woody fuel particles is conducted to determine the burning characteristics of firebrands. Then the trajectories and burning rates of disk-shaped firebrands lofted by the crown fire plume and transported downwind are calculated for various values of the wind speed, U wind , and of the fire intensity, I . Firebrands of different sizes and densities are first launched from a specified location at the top of the canopy. Firebrands that fall on the ground are in a flaming or a glowing state depending on the product ρ w 0 f × τ (ρ w 0 f : initial firebrand density, τ : firebrand thickness). Results show that for firebrands that remain longer in the thermal plume, the distance covered upon landing is independent of the initial particle diameter and correlates well with I 0.1 U 0.9 wind (ρ w 0 f × τ ) −0.2 . The normalized brand mass fraction at landing also correlates with the flight time normalized by the product ρ w 0 f × τ for flaming firebrands or by the product ρ w 0 f × D 5/3 0 (D 0 : initial firebrand diameter) for glowing firebrands. For firebrands released from random locations within the canopy, the above correlations remain unchanged, thereby demonstrating the generality of the developed approach.

This article describes experiments in which happy or sad moods were induced in subjects by hypnotic suggestion to investigate the influence of emotions on memory and thinking. One result was that subjects exhibited mood-state-dependent memory in recall of word lists, personal experiences recorded in a daily diary, and childhood experiences; people recalled a greater percentage of those experiences that were affectively congruent with the mood they were in during recall. Second, emotion powerfully influenced such cognitive processes as free associations, imaginative fantasies, social perceptions, and snap judgments about others' personalities (e.g., angry subjects generated angry associates, told hostile stories, and were prone to find fault with others). Third, when the feeling-tone of a narrative agreed with the reader's emotion, the salience and memorability of events in that narrative were increased. Thus, sad readers attended more to sad material, identified with a sad character from a story, and recalled more about that character. An associative network theory is proposed to account for these several results. In this theory, an emotion serves as a memory unit that can enter into associations with coincident events. Activation of this emotion unit aids retrieval of events associated with it; it also primes emotional themata for use in free association, fantasies, and perceptual categorization.

Using a Spanish database, we have explored the role of persistence in the decision of firms to implement product and process innovations and to develop those innovations. We assume that a company that is continuously engaged in some type of innovation activity will be encouraged to innovate, either for investment reasons or to enhance its market image. Because of the effects of persistence (state dependence) could be contaminated by unobserved heterogeneity, we use panel data, and make an effort to separate these effects. We demonstrate that persistence is important in both innovation decisions. Persistence in innovation increases at least 15% the probability to develop more innovations. A second important result is that the introduction of the alternative innovation increases the probability to innovate in a range from 2 to 4%; it implies that complementarities between innovations are also important in the decision to continue innovating in terms of absorbed synergies and capacities generated by the firm.

The hypothalamo-pituitary-adrenal (HPA) axis is the critical mediator of the vertebrate stress response system, responding to environmental stressors by maintaining internal homeostasis and coupling the needs of the body to the wants of the mind. The HPA axis has numerous complex drivers and highly flexible operating characterisitics. Major drivers include two circadian drivers, two extra-hypothalamic networks controlling top-down (psychogenic) and bottom-up (systemic) threats, and two intra-hypothalamic networks coordinating behavioral, autonomic, and neuroendocrine outflows. These various networks jointly and flexibly control HPA axis output of periodic (oscillatory) functions and a range of adventitious systemic or psychological threats, including predictable daily cycles of energy flow, actual metabolic deficits over many time scales, www.elsevier.com/locate/pneurobio

Background: Utilization of maternal health services is associated with improved maternal and neonatal health outcomes. Considering global and national interests in the Millennium Development Goal and Nigeria's high level of maternal mortality, understanding the factors affecting maternal health use is crucial. Studies on the use of maternal care services have largely overlooked community and other contextual factors. This study examined the determinants of maternal services utilization in Nigeria, with a focus on individual, household, community and state-level factors.

Background: Utilization of maternal health services is associated with improved maternal and neonatal health outcomes. Considering global and national interests in the Millennium Development Goal and Nigeria's high level of maternal mortality, understanding the factors affecting maternal health use is crucial. Studies on the use of maternal care services have largely overlooked community and other contextual factors. This study examined the determinants of maternal services utilization in Nigeria, with a focus on individual, household, community and state-level factors.

The purpose of this tutorial is to survey queueing networks, a class of stochastic models extensively applied to represent and analyze resource sharing systems such as communication and computer systems. Queueing networks (QNs) have been proved to be a powerful and versatile tool for system performance evaluation and prediction. First we briefly survey QNs that consist of a single service center, i.e., the basic queueing systems defined under various hypotheses, and we discuss their analysis to evaluate a set of performance indices, such as resource utilization and throughput and customer response time. Their solution is based on the introduction of an underlying stochastic Markov process. Then, we introduce QNs that consist of a set of service centers representing the system resources that provide service to a collection of customers that represent the users. Various types of customers define the customers classes in the network that are gathered in chains. We consider various analytical methods to analyze QNs with single-class and multiple-class. We mostly focus on product-form QNs that have a simple closed form expression of the stationary state distribution that allows to define efficient algorithms to evaluate average performance measures. We review the basic results, stating from the BCMP theorem that defines a large class of product-form QNs, and we present the main solution algorithms for single-class e multiple-class QNs. We discuss some interesting properties of QNs including the arrival theorem, exact aggregation and insensitivity. Finally, we discuss some particular models of product-form QNs that allow to represent special system features such as state-dependent routing, negative customers, customers batch arrivals and departures and finite capacity queues. The class of QN models is illustrated through some application examples of to analyze computer and communication systems.

In the present study, the multidimensional Trait and State Food Cravings Questionnaires (FCQ-T and FCQ-S), as developed by The development and validation of the State and Trait Food Cravings Questionnaires. Behavior Therapy, 31, 151-173], were modified in order to construct an index of general food craving instead of specific food craving. The factor structure, validity and reliability of the modified questionnaires, renamed as the Trait and State General Food Cravings Questionnaires (G-FCQ-T and G-FCQ-S), were investigated in three separate studies. Firstly, exploratory factor analyses were conducted, which yielded a G-FCQ-T with a four-factor structure, that was considerably shorter as compared to the original (nine-factor) FCQ-T, and a G-FCQ-S of which the factor structure was highly comparable to the original FCQ-S. Secondly, in an attempt to replicate the factor structures of the G-FCQ-T and the G-FCQ-S as found in Study 1, confirmative factor analyses were performed. Results indicated adequate fits for both questionnaires. In addition, the test-retest reliability of both versions was satisfactory and an analysis of the construct validity generally revealed the expected results. In Study 3, the validity of the state version of the G-FCQ was further investigated by relating scores on this questionnaire to indices of food deprivation and satiation. Results indicated that the G-FCQ-S indeed measures food craving as a variable state, which is influenced by situational and temporal variables. Altogether, it can be concluded that the G-FCQ-T and G-FCQ-S are both reliable and valid measures of general trait-like and state-dependent food craving. r