Classical frustrated XY model: Continuity of the ground-state energy as a function of the frustration.
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OBJECTIVE: To identify differences between patients viewed as frustrating by their physicians and those considered typical and satisfying. DESIGN: This cross-sectional observational study focused on psychologically distressed high users of medical services. Frustrating patients were compared with typical and satisfying patients, using data from patient questionnaires, physician assessments, structured psychiatric interviews, and computerized utilization records. SETTING: Group Health Cooperative of Puget Sound, a large health maintenance organization. PATIENTS/PARTICIPANTS: Study patients were in the top decile for ambulatory visits, and bad elevated scores for anxiety, depression, and somatization. Among the 339 patients invited to participate in the study, 251 agreed, and 228 were rated by their physicians. MAIN RESULTS: A substantial proportion (37%) of the high users were viewed as frustrating by their physicians. Physicians' ratings of physical disease severity did not differ among the groups, but frustrating patients rated their own health status less favorably and reported more somatic symptoms and disabilities. The frustrating group utilized more medical services than did other distressed high utilizers. All three groups had a high prevalence of mental disorders. However, frustrating patients had higher rates of somatization and generalized anxiety disorder. CONCLUSIONS: Physicians and their frustrating patients had contrasting views of the patients' illnesses. The best predictors of physician frustration were somatization and increased medical service utilization. There is need for further research and clinical attention concerning optimal clinical management for patients with somatization.
BACKGROUND: Literature on difficult doctor-patient relationships has focused on the "difficult patient." Our objective was to determine physician and practice characteristics associated with greater physician-reported frustration with patients. METHODS: We conducted a secondary analysis of the Physicians Worklife Survey, which surveyed a random national sample of physicians. Participants were 1391 family medicine, general internal medicine, and medicine subspecialty physicians. The survey assessed physician and practice characteristics, including stress, depression and anxiety symptoms, practice setting, work hours, case-mix, and control over administrative and clinical practice. Physicians estimated the percentage of their patients who were "generally frustrating to deal with." We categorized physicians by quartile of reported frustrating patients and compared characteristics of physicians in the top quartile to those in the other three quartiles. We used logistic regression to model physician characteristics associated with greater frustration. RESULTS: In unadjusted analyses, physicians who reported high frustration with patients were younger (p < 0.001); worked more hours per week (p = 0.041); and had more symptoms of depression, stress, and anxiety (p < 0.004 for all). In the final model, factors independently associated with high frustration included age < 40 years, work hours > 55 per week, higher stress, practice in a medicine subspeciality, and greater number of patients with psychosocial problems or substance abuse. CONCLUSION: Personal and practice characteristics of physicians who report high frustration with patients differ from those of other physicians. Understanding factors contributing to physician frustration with patients may allow us to improve the quality of patient-physician relationships.
The behaviour of three biologically inspired networks is investigated: Immune Idiotypic Network (IIN), Hopfield Network (HN) and Coupled Map Lattice (CML), mainly the effect on the dynamics induced by connecting the network in a frustrated way. Frustration occurs when the global structure is such that local connectivity patterns responsible for stable behaviour are intertwined, leading to mutually competing attractors and chaotic itinerancy among brief appearance of these attractors. Frustration destabilizes the network and provokes an unpredictable "wavering" among the stable dynamic regimes which characterize the same network when it is interconnected in a non-frustrated way. As the main contribution of this paper, an immune idiotypic network in which the prevailing behaviour is oscillatory is studied in detail. It is shown how connecting an elementary three-clone network in a frustrating way transforms the oscillatory regime into a chaotic one. This chaotic regime is further analysed and several interesting aspects are discussed such as the variable homogeneity, the intrinsic chaotic itinerancy among brief oscillatory regimes and the strong unpredictability. In addition, dynamical regimes obtained by frustrating the connectivity of HN and CML are presented and the similarities as well as the differences with the IIN dynamics are emphasized. Common to all these networks is the description of the frustrated chaos as a succession of attempts to relax the network into one of the oscillatory regimes given by a weaker and non-frustrated connectivity, an impossible achievement making the dynamics rambling over brief but repelling orbits.
BACKGROUND: A surgeon's level of frustration when performing an operation and level of satisfaction at completion may be correlated with patients' outcomes. We evaluated the relationship between the attending surgeons' frustration and satisfaction and recurrence and complications of open and laparoscopic inguinal hernia repair. STUDY DESIGN: Men with detectable inguinal hernias were randomized to undergo open or laparoscopic herniorrhaphy at 14 Veterans Affairs hospitals. After completion of the procedure, surgeons were asked to assess their level of frustration during the operation and their overall satisfaction with the operative result. Two subjective scales ranging from 1 (not frustrated/not satisfied) to 5 (very frustrated/very satisfied) were used to independently assess both parameters. Reasons for surgeon frustration were evaluated. Patients were followed for 2 years for recurrence and complications. RESULTS: Of 1,983 patients who underwent hernia repair, 1,622 were available for analysis; 808 had open repair and 813 had laparoscopic repair. Surgeons reported less frustration and more satisfaction with open than with laparoscopic repair (p = 0.0001 and 0.0001, respectively). Frustration was associated with a higher rate of hernia recurrence at 2 years (adjusted odds ratio, 2.01, 95% CI, 1.15-3.51) in open repair, and a higher overall rate of postoperative complications (adjusted odds ratio, 1.27, 95% CI, 1.03-1.56) in both open and laparoscopic hernia repair. Satisfaction was not correlated with recurrence or complications. CONCLUSIONS: The level of a surgeon's frustration during performance of an inguinal herniorrhaphy was a better predictor of outcomes of the operation than was satisfaction with the procedure. Sources of intraoperative frustration should be controlled to improve outcomes.
Frustration, defined as a competition between interactions such that not all of them can be satisfied, is important in systems ranging from neural networks to structural glasses. Geometrical frustration, which arises from the topology of a well-ordered structure rather than from disorder, has recently become a topic of considerable interest. In particular, geometrical frustration among spins in magnetic materials can lead to exotic low-temperature states, including 'spin ice', in which the local moments mimic the frustration of hydrogen ion positions in frozen water. Here we report an artificial geometrically frustrated magnet based on an array of lithographically fabricated single-domain ferromagnetic islands. The islands are arranged such that the dipole interactions create a two-dimensional analogue to spin ice. Images of the magnetic moments of individual elements in this correlated system allow us to study the local accommodation of frustration. We see both ice-like short-range correlations and an absence of long-range correlations, behaviour which is strikingly similar to the low-temperature state of spin ice. These results demonstrate that artificial frustrated magnets can provide an uncharted arena in which the physics of frustration can be directly visualized.
We used three studies to examine the validity of hostility scores from the Children's Form of the Picture-Frustration (P-F) Study in the context of Dodge's (1986) social information-processing model of aggression. Dodge's theory states that frustration results in retaliatory aggression only if the frustrated individual attributes hostile intent to the frustrator. Further, differences between aggressive and nonaggressive children in retaliatory aggression are more likely when the frustrator's intent is ambiguous than when the frustrator's intent is clear. In Study 1, items on the Children's P-F Study were rated by 237 children according to how mean they believed the frustrator in each item was. Results showed that items varied significantly in the amount of hostility portrayed. On the basis of these ratings, items were divided into those in which the intent was hostile, nonhostile, or ambiguous. In Studies 2 and 3, we tested Dodge's theory that differences between aggressive and nonaggressive children would be revealed on those items in which the frustrator's intention is ambiguous. In both studies, teacher's ratings of children's retaliatory aggression correlated significantly with the scale comprised of the ambiguous items but not with the scales comprised of the hostile or nonhostile items. The results provide further support to Dodge's theory of aggression and to the use of the Children's P-F Study within a social-cognitive perspective.
Recent studies of the doctor-patient relationship have shown that certain patients are perceived as frustrating or difficult by their doctors; however, little is known about the characteristics of these patients that elicit this dissatisfaction. As part of a larger study of rheumatology clinic patients with fibromyalgia or rheumatoid arthritis (N = 68) we used stepwise multiple regression to select the factors most associated with physician frustration while controlling for the effects of other variables. Variable domains included demographics, psychiatric diagnoses, personality factors, functional disability, disease state, and trauma history. These domains as well as individual variables within these domains were systematically evaluated for their unique contribution to the prediction of physician frustration as measured by the Difficult Doctor-Patient Relationship Questionnaire (DDPRQ). Initial bivariate correlates of physician frustration included marital status, current dysthymia and agoraphobia, lifetime panic disorder and obsessive-compulsive disorder, adult rape and physical abuse, somatization disorder, physical and social disability, the presence of fibromyalgia, as well as neuroticism, illness impact, and perceived loss of control. The best multivariable model for estimating frustration magnitude included somatization disorder, perception of lack of control over illness, and a lifetime history of obsessive-compulsive disorder. These factors explained 48% of the variance in DDPRQ score. Physicians in this study were most frustrated with patients who had ongoing preoccupation with multiple medically unexplained physical symptoms as well as the perception of greater impact and lack of control over their illness. These findings suggest that treatment of somatization in patients with chronic symptoms may decrease physician frustration.
Effects of anger induction procedures such as frustration and harassment on cardiovascular reactivity have been demonstrated in a wide range of experimental situations. Similarly, heightened cardiovascular reactivity has been associated with a diverse range of tasks involving active coping, competition and interpersonal interaction. The present study sought to directly compare the relative effects of these two important ways of inducing cardiovascular changes. One hundred and five university students performed two tasks that differed in the degree of active coping and interpersonal competition: a competitive psychomotor task and a problem-solving task. States of anger were induced during both tasks by means of harassment, frustration or frustration+harassment. Task-related changes in heart rate, systolic blood pressure, diastolic blood pressure, pulse volume amplitude and respiratory sinus arrhythmia amplitude were monitored. The competitive psychomotor task produced greater cardiovascular reactivity than did the problem-solving task. Harassment and frustration+harassment provoked more cardiovascular reactivity than did frustration alone. However, harassment and frustration+harassment had the greatest cardiovascular effects in the competitive task, whereas frustration had the greatest cardiovascular effects in the problem-solving task. In this sense, the increases on cardiovascular reactivity seem to depend on the interaction between anger induction procedures and the context in which anger is provoked.
Three related experiments were performed to examine trial-to-trial differences in production of frustration odor during runway extinction by rats that had received 0, 2, 4, or 6 prior rewards. Differences in odor production were indexed by the subsequent speed of escape from the runway goal box by conspecifics. The results indicated that (a) subjects will perform a hurdle-jump response to escape from frustration odor; (b) escape performance even after several prior escape trials accurately reflects trial-to-trial changes in production of frustration odor; and (c) production of frustration odor requires only 4 prior rewards. Implications of the present data for frustration analyses of the limited-trial partial reinforcement effect and future investigations of frustration odor are discussed.
This study reports 1-year follow-up data on the children originally observed by Goldberg and Lewis in a barrier frustration situation. Changes in reactions to frustration over a 2-year time span were examined for age and sex differences. Regardless of sex, over the first 2 years of life, barrier frustration was responded to with a decrease in stress and an increase in problem-solving behavior. The data suggest that sex differences in success at coping with the frustration may change with age and may be dependent on what behaviors are considered to be more instrumental in solving the frustration. Sex differences related to behavior in the barrier frustration were highly age specific. As previously reported in Goldberg and Lewis, at 1 year of age boys cried less and made more active attempts to get around the barrier than girls. However, at 2 years of age, girls vocalized more for help from the mother and made more attempts at problem solving than boys.
Thwarting of feeding behaviour in the laying hen results in an increase in stereotyped pacing, displacement preening, and the gakel-call. These behaviours therefore reflect the frustration arousal caused by the thwarting of feeding behaviour. This raises the question whether the level of frustration also varies with the intensity of the motivation to perform the thwarted behaviour. This study investigated the relationship between the intensity of the motivation and level of frustration on the one hand and the gakel-call on the other hand. In Experiment 1, the strength of the motivation to feed was varied by thwarting hens in their feeding behaviour in an operant procedure after different durations of food deprivation (0, 8, 23 and 47 h). Trend analysis showed that with increasing hunger state, an increasing number of gakel-calls was given. No effect of treatments on temporal characteristics of the gakel-call was found. In Experiment 2, the level of frustration was varied by reducing or increasing the duration of access to food for food-deprived hens compared to the duration of access during training. It was assumed that a shorter duration of access to food compared to training would elicit frustration, which in turn would affect the performance of behaviours indicative of thwarting. However, we found neither a relation between the number of gakel-calls nor the temporal features of the gakel-call and the duration of access to food. Possibly, the differences between treatments were not large enough to induce differences in frustration level. Also, other factors that might have influenced the motivation are discussed.
In a previous paper we introduced the notion of frustrated chaos occurring in Hopfield networks [Neural Networks 11 (1998) 1017]. It is a dynamical regime which appears in a network when the global structure is such that local connectivity patterns responsible for stable oscillatory behaviors are intertwined, leading to mutually competing attractors and unpredictable itinerancy among brief appearance of these attractors. Frustration destabilizes the network and provokes an erratic 'wavering' among the orbits that characterize the same network when it is connected in a non-frustrated way. In this paper, through a detailed study of the bifurcation diagram given for some connection weights, we will show that this frustrated chaos belongs to the family of intermittency type of chaos, first described by Berge et al. [Order within chaos (1984)] and Pomeau and Manneville [Commun. Math. Phys. 74 (1980) 189]. Indeed, the transition to chaos is a critical one, and all along the bifurcation diagram, in any chaotic window, the duration of the intermittent cycles, between two chaotic bursts, grows as an invert ratio of the connection weight. Specific to this regime are the intermittent cycles easily identifiable as the non-frustrated regimes obtained by altering the values of these same connection weights. We will more specifically show that anywhere in the bifurcation diagram, a chaotic window always lies between two oscillatory regimes, and that the resulting chaos is a merging of, among others, the cycles at both ends. The strength (i.e. the duration of its oscillatory phase before the chaotic burst) of the first cycle decreases while the regime tends to stabilize into the second cycle (with the strength of this second cycle increasing) that will finally get the control. Since in our study, the bifurcation diagram concerns the same connection weights responsible for the learning mechanism of the Hopfield network, we will discuss the relations existing between bifurcation, learning and control of chaos. We will show that, in some cases, the addition of a slower Hebbian learning mechanism onto the Hopfield networks makes the resulting global dynamics to drive the network into a stable oscillatory regime, through a succession of intermittent and quasiperiodic regimes. Finally, we will present a series of possible logical steps to manually construct a frustrated network.
Frustration in a network described by a set of ordinary differential equations induces chaos when the global structure is such that local connectivity patterns responsible for stable oscillatory behaviours are intertwined, leading to mutually competing attractors and unpredictable itinerancy among brief appearance of these attractors. Frustration destabilizes the network and provokes an erratic 'wavering' among the periodic saddle orbits which characterize the same network when it is connected in a non-frustrated way. The characterization of chaos as some form of unpredictable 'wavering' among repelling oscillators is rather classical but the originality here lies in the identification of these oscillators as the stable regimes of the 'non-frustrated' network. In this paper, a simple and small 6-neuron Hopfield network is treated, observed and analyzed in its chaotic regime. Given a certain choice of the network parameters, chaos occurs when connecting the network in a specific way (said to be 'frustrated') and gives place to oscillatory regimes by suppressing whatever connection between two neurons. The compositional nature of the chaotic attractor as a succession of brief appearances of orbits (or parts of orbits) associated with the non-frustrated networks is evidenced by relying on symbolic dynamics, through the computation of Lyapunov exponents, and by computing the autocorrelation coefficients and the spectrum.
Magnetic ground states in solids often arise as a result of a delicate balance between competing factors. One currently active area of research in magnetic materials involves compounds in which long-range magnetic ordering at low temperatures is frustrated by the geometry of the crystalline lattice, a situation known as geometrical magnetic frustration. The number of systems known to display the effects of such frustration is growing, but those that are sufficiently simple from theoretical, chemical, and physical perspectives to allow for detailed understanding remain very few. A search for model compounds in this family has led us to the double perovskites Ba2LnSbO6 and Sr2LnSbO6 (Ln = Dy, Ho, and Gd) reported here. Ba2DySbO6,Ba2HoSbO6,Sr2DySbO6, and Sr2HoSbO6 are structurally characterized by powder neutron diffraction at ambient temperature. The trivalent lanthanides and pentavalent antimony are found to be fully ordered in the double-perovskite arrangement of alternating octahedra sharing corner oxygens. In such a structure, the lanthanide sublattice displays a classical fcc arrangement, an edge-shared network of tetrahedra known to result in geometric magnetic frustration. No magnetic ordering is observed in any of these compounds down to temperatures of 2 K, and in the case of the Dy-based compounds in particular, frustration of the magnetic ordering is clearly present. Lanthanide-based double perovskites are proposed to be excellent model systems for the detailed study of geometric magnetic frustration.
The ultrastructural appearance of axons regenerating after crush injury was examined in rat sciatic nerves in which proximodistal growth was interrupted (frustrated regeneration) by placement of a tight ligature 1 cm distal to the original crush injury, and in nerves lacking a distal tie (unimpeded regeneration). Examination of unimpeded regenerating axons four and seven days after injury showed minute axonal sprouts as well as scattered dilated (2-10 microns) axonal profiles containing large numbers of anastomosing tubulovesicular elements and vacuoles. These dilated profiles were consistent with the appearance of growth cones, the motile tips of regenerating axons, as described in various in vivo and in vitro systems. The ultrastructural appearance of regenerating axons accumulating proximal to a frustrating tie was a function of time after arrival at the ligature. At the earliest time examined (one week) large numbers of axonal profiles accumulated at the ligature which were qualitatively similar to growth cones seen in unimpeded regeneration, although slightly larger in diameter. With time, the uniform population of growth cones proximal to the frustrating ligature was replaced by dilated axons containing large numbers of neurofilaments, dense collections of heterogeneous membranous organelles, or delicate to coarse tubulovesicular elements admixed with a variety of subcellular organelles. Rare examples of axonal dystrophy were demonstrated after chronic frustration of regeneration; however, they represented only a small percentage (less than 1%) of frustrated axons. Frustrated regeneration was accompanied by scattered examples of demyelination/remyelination of large axons proximal to the ligature as well as transperineurial growth of axons as microfascicles to escape the site of ligation.
To understand the origin of the dynamical transition, between high-temperature exponential relaxation and low-temperature nonexponential relaxation, that occurs well above the static transition in glassy systems, a frustrated spin model, with and without disorder, is considered. The model has two phase transitions, the lower being a standard spin glass transition (in the presence of disorder) or fully frustrated Ising (in the absence of disorder), and the higher being a Potts transition. Monte Carlo results clarify that in the model with (or without) disorder the precursor phenomena are related to the Griffiths (or Potts) transition. The Griffiths transition is a vanishing transition which occurs above the Potts transition and is present only when disorder is present, while the Potts transition which signals the effect due to frustration is always present. These results suggest that precursor phenomena in frustrated systems are due either to disorder and/or to frustration, giving a consistent interpretation also for the limiting cases of Ising spin glass and of Ising fully frustrated model, where also the Potts transition is vanishing. This interpretation could play a relevant role in glassy systems beyond the spin systems case.