Experimental study of the fluctuation theorem in a nonequilibrium steady state.

The fluctuation theorem (FT) quantifies the probability of second law violations in small systems over short time scales. While this theorem has been experimentally demonstrated for systems that are perturbed from an initial equilibrium state, there are a number of studies suggesting that the theorem applies asymptotically in the long time limit to systems in a nonequilibrium steady state. The asymptotic application of the FT to such nonequilibrium steady states has been referred to in the literature as the steady-state fluctuation theorem (or SSFT). In this paper, we demonstrate experimentally the application of the FT to nonequilibrium steady states, using a colloidal particle localized in a translating optical trap. Furthermore, we show, for this colloidal system, that the FT holds under nonequilibrium steady states for all time, and not just in the long time limit, as in the SSFT.

Reversibility in nonequilibrium trajectories of an optically trapped particle.

The fluctuation theorem (FT) describes how a system's thermodynamic irreversibility develops in time from a completely thermodynamically reversible system at short observation times, to a thermodynamically irreversible one at infinitely long times. In this paper, we present a general definition of the dissipation function Omega(t), the quantitative argument in the fluctuation theorem (FT), that is a measure of a system's irreversibility. Originally cast for deterministic systems, we demonstrate, through the example of two recent experiments, that the dissipation function can be defined for stochastic systems. While the ensemble average of Omega(t) is positive definite irrespective of the system for which it is constructed, different expressions for Omega(t) can arise in stochastic and deterministic systems. Moreover, within the stochastic framework, Omega(t) is not unique. Nevertheless, each of these expressions for Omega(t) satisfies the FT.

Fluctuations and irreversibility: an experimental demonstration of a second-law-like theorem using a colloidal particle held in an optical trap.

The puzzle of how time-reversible microscopic equations of mechanics lead to the time-irreversible macroscopic equations of thermodynamics has been a paradox since the days of Boltzmann. Boltzmann simply sidestepped this enigma by stating "as soon as one looks at bodies of such small dimension that they contain only very few molecules, the validity of this theorem [the second law of thermodynamics and its description of irreversibility] must cease." Today we can state that the transient fluctuation theorem (TFT) of Evans and Searles is a generalized, second-law-like theorem that bridges the microscopic and macroscopic domains and links the time-reversible and irreversible descriptions. We apply this theorem to a colloidal particle in an optical trap. For the first time, we demonstrate the TFT in an experiment and show quantitative agreement with Langevin dynamics.

A neural network approach to identifying adolescent adjustment.

This study examined the relationship between the quality of adjustment in adolescents and a set of psychiatric diagnoses, personality traits, parental bonding, and social support variables. One hundred fifty adolescents were administered the Millon Adolescent Personality Inventory, the Parental Bonding Questionnaire, the Social Support Questionnaire, and the Diagnostic Interview for Children and Adolescents. A neural network approach was then utilized, and it was found that several of the variables (e.g., Major Depressive Disorder, Conduct Disorder, and Societal Conformity) had a significant role in classifying adolescents into three groups: maladjusted, nominally adjusted, and well-adjusted.

Individual characteristics and peer relations of psychiatrically hospitalized aggressive youths: implications for treatment.

OBJECTIVE: This study identified individual and peer-relations problems of inpatient youths who are aggressive, and whether youths who are aggressive in two settings have greater treatment needs than youths who are aggressive in one setting only. METHODS: 85 youths aged 10 to 16 years who were consecutively admitted to a psychiatric facility served as participants. Based on ratings by parents and hospital staff, youths were identified as aggressive in the community only, aggressive in the hospital only, aggressive in both settings, or nonaggressive. Dependent measures consisted of youth self-reports and ratings by parents and hospital staff. RESULTS: Youths who demonstrate aggressive behavior in two settings have more nonaggressive behavior problems, more disturbed peer relations, and more hostile thinking than do nonaggressive youths, and some youths, although they may behave aggressively during hospitalization, have similar treatment needs as nonaggressive youths. CONCLUSIONS: Mental health professionals who work with youths in psychiatric settings need to develop treatment plans that directly address the more severe externalizing problems, hostile thinking, and peer problems of aggressive youths over and above that of nonaggressive youths, and should be aware that youths who behave aggressively during hospitalization may not have problems more severe than those of nonaggressive youths.

Panic disorder in hospitalized cancer patients.

Cancer is commonly complicated by psychiatric comorbidity, particularly depression. However, the effects of panic on cancer treatment and cancer patients' quality of life are not well understood. To examine more closely the occurrence of panic attacks and panic disorder in cancer patients, we retrospectively reviewed charts of 106 consecutive psychosomatic consultations of inpatients with cancer at a regional cancer center. Approximately one-fifth of the patient sample presented with panic attacks or panic disorder at the time of the consultation. We present four case examples to demonstrate the potential effect of panic on cancer patients, including requests for cancer treatment discontinuation. We report resolution of panic with benzodiazepine and selective serotonin reuptake inhibitors.

Perceived family characteristic differences between depressed and anxious children and adolescents.

BACKGROUND: The present study compared anxious vs. depressed children's and adolescents' perceptions about their family environment. METHODS: One hundred inpatient youngsters were interviewed for the study. Of these participants, 21 who met criteria for a depressive disorder without an anxiety disorder and 18 who met criteria for an anxiety disorder without a depressive disorder were compared on several self-report family measures. These measures included the Family Adaptability and Cohesion Evaluation Scales-II (FACES-II), Family Strengths, and Social Support Questionnaire-Revised (SSQS-R). RESULTS: Youngsters with depressive disorders reported having less pride in their families and perceived their families as being less adaptable to problems than did anxious children. Also, depressed children expressed lower levels of satisfaction with their social network than did anxious children. LIMITATIONS: The fact that our study only included reports from inpatient youngsters, families of anxious and depressed children may differ in the way family members relate to one another and in the way they deal with everyday problems. CONCLUSIONS: Based on the evidence obtained in this study, anxiety and depression may be two distinct internalizing disorders with specific family characteristics.

Digital images in the diagnosis of wound healing problems.

The use of digital wound images could allow remote consultation among patients, physicians, or other care-givers located at quite distant sites by means of the Internet. To evaluate the efficacy and validity of digital images for the evaluation of wounds, the ability and reliability of surgeons to diagnose and make treatment suggestions using digital images of several types of wounds were compared. Twenty-four wound images on 35-mm slides were selected for use in this study. Each slide image was digitized at 24-bit color with a resolution of 640 pixels horizontal by 425 pixels vertical and stored as a JPEG file. These images were then presented as a slide show on a video monitor, with resolution set at 640 x 480. Six physicians examined the images, first in digital format and later in the original slide form. Each observer assessed each wound and possible treatment options by filling out a questionnaire using a series of yes/no questions. For all observers, there was an 87 percent agreement between digital and slide images (p = 0.004). The agreement between the digital and slide images was measured for each individual observer using a kappa coefficient. The agreement level corresponded to the experience of the observer, with the kappa values ranging from greater than 0.8 (almost perfect agreement) for the attending plastic surgeon to just greater than 0.5 (moderate agreement) for the intern. With this study, the feasibility of distance wound consultation using digital images of a quality consistent with consumer-grade digital photography was demonstrated.

Stress reactions of children and adolescents in war and siege conditions.

OBJECTIVE: This was a study of posttraumatic stress symptoms in children and adolescents during siege conditions in Sarajevo. METHOD: Seven hundred ninety-one students aged 7-15 years were surveyed to assess symptoms of posttraumatic stress and level of deprivation. RESULTS: Girls reported more stress than boys. Loss of family members and deprivation of basic needs were associated with more symptoms. CONCLUSIONS: Personal experiences of siege are related to increased stress.

"Anxious suicidality": a new subtype of childhood suicide ideation?

The current study examined the presence of anxiety in children with suicide ideation. From a sample of 100 inpatients, children who displayed suicide ideation (n = 27) were selected and divided into two groups, high and low anxiety. Findings indicated that children with suicide ideation and anxiety were less happy and satisfied, experienced more negative life events, and were more distractible and intense than children with suicide ideation only. Additionally, according to their self-reports, parents of children with high anxiety reported more obsessive-compulsive and anxiety symptoms as well as greater hostility than parents of children with low anxiety. The authors have identified a subgroup of children with suicide ideation who are highly anxious and can be termed as experiencing "anxious suicidality."

Family characteristics and behavior problems of suicidal and non-suicidal children and adolescents.

The present study examined familial and individual variables in youngsters at high risk for suicide and non-suicidal youngsters. One hundred inpatient children and adolescents completed a battery of questionnaires including, FACES II, Family Strengths, and Problem Behavior Scales, to assess family dysfunction and individual behavior problems. The results indicated that suicidal youngsters have lower pride in their families and perceived them as less adaptable than non-suicidal youngsters as indicated by scores on the Family Strengths and FACES II, respectively. Scores on the Problem Behavior Scales indicated that suicidal youngsters also exhibited self-inflicted behaviors, withdrawal from others, little interest in activities, poor concentration, and difficulties with sleeping. In addition, youths at risk for suicide were more likely to be diagnosed with a mood disorder, including major depressive disorder and dysthymia, as well as substance abuse and phobias. These findings suggest that suicidal youngsters' negative perceptions of their families and their maladaptive behaviors should be given special attention in designing appropriate interventions. In this way, treatment would likely be effective by providing appropriate coping skills and preventing future suicidal attempts in high risk youngsters.

Parental hostility: impact on the family.

This study examined the effects of parental hostility on the families of 100 psychiatrically hospitalized children. Parents and their children were administered an assessment battery. The results for families who scored high on parental hostility were compared to families with low parental hostility. Parents who exhibited high hostility scored differently on a variety of temperament constructs (e.g., lower adaptability, worse mood, and lower rhythmicity) than parents who scored low in hostility. High parental hostility was also associated with an elevated level of family relation problems, which includes family effectiveness and cohesion.

Development and validation of an exercise performance support system for people with lower extremity impairment.

OBJECTIVE: To identify innovative strategies to support appropriate, self-directed exercise that increase physical activity levels of people with arthritis. This article reports on one interactive, multimedia exercise performance support system (PSS) for people with lower extremity impairments in strength or flexibility. METHODS: An interdisciplinary team developed the PSS using self-report of lower extremity musculoskeletal impairments (flexibility and strength) to produce an individualized exercise program with video and print educational materials. Initial evaluation has investigated the validity and reliability of program assessments and recommendations. RESULTS: PSS self-report and professional assessments were similar, with more impairments indicated by self-report. PSS exercise recommendations were similar to those made by 3 expert physical therapists using the same exercise data base. Results of PSS impairment assessments were stable over a 1-week period. CONCLUSION: PSS exercise recommendations appear to be reliable and a valid reflection of current exercise knowledge in rheumatology. Furthermore, users were able to complete the computer-based program with minimal assistance and reported it to be enjoyable and informative.

Diagnostic quality of low resolution images for tele-woundcare.

The use of digital wound images would allow remote consultation between patients, physicians, or other caregivers over the Internet. To evaluate the efficacy and validity of digital images for assessment of wounds, we compared the ability and reliability of surgeons to diagnose and make treatment suggestions using either digital or slide images of several types of wounds. Twenty-four wound images on 35-mm slides were selected for use in this study. Each slide image was digitized at 24-bit color with a resolution of 640 pixels horizontal by 425 pixels vertical, and stored as a JPEG file. Six physicians, of varying experience, examined the images, first in digital format and then later in the original slide form. Each observer assessed each wound for condition and possible treatment options by filling out a questionnaire using a series of yes/no questions. For all observers, there was an 87% agreement of answers between digital and slide images (p = 0.004). The agreement between the digital and slide images was also measured for each individual observer using a kappa coefficient. The agreement kappa correlated with the experience of the observer, with the kappa values ranging from greater than 0.8 (almost perfect agreement) for an experienced woundcare professional to just greater than 0.5 (moderate agreement) for a surgical intern. With this study, we have demonstrated the feasibility of distance wound consultation using digital images of a quality consistent with consumer-grade digital photography.

Hopelessness in inpatient youths: a closer look at behavior, emotional expression, and social support.

OBJECTIVE: To examine the individual and family characteristics of children and adolescents with high levels of hopelessness. METHOD: One hundred inpatient youngsters participated in the study. Several measures, including the Hopelessness Scale for Children, Problem Behavior Scale of the Scales of Independent Behavior, Social Support Questionnaire-Revised, Pediatric Anger Expression Scale, and Differential Emotions Scale, were used to compare differences between youngsters who scored high or low on hopelessness. RESULTS: The results indicated that youngsters with high hopelessness scores tended to perceive their families and peers as providing little support, to express their anger overtly and aggressively, and to demonstrate more negative emotions than youngsters with low hopelessness scores. CONCLUSIONS: Hopelessness in youths appears to be associated with a specific pattern of behavioral and emotional problems. Clinical implications of the findings include integrating anger management, emotional expression interventions, and involving the family in treatment to enhance the social support network of youngsters with high levels of hopelessness.

Dysthymic disorder in clinically referred preschool children.

OBJECTIVE: This clinical and descriptive study examined the existence, phenomenology, and frequency of dysthymic disorder in a sample of clinically referred preschool children. In addition, the frequency of DSM-IV symptoms and the alternative research criterion for dysthymic disorder were investigated. METHOD: Three hundred consecutive preschool admissions (aged 2 to 6 years) to a child development unit were given a comprehensive evaluation by a treatment team. Data were collected from multiple informants based on the suitability of each source. RESULTS: The findings indicated that eight children met criteria for dysthymic disorder according to the DSM-IV criteria and the alternative research criterion for dysthymic disorder. CONCLUSIONS: The results support the existence of dysthymic disorder in preschool-age children. Recommendations are made for future versions of DSM as well as the appropriateness and significance of various sources of information, such as the child, parents, teachers, and clinician observations, for the evaluation of symptoms of dysthymic disorder in preschoolers.

Intrafamilial homicide committed by juveniles: examination of a sample with recommendations for prevention.

The current study examines a sample of 112 adolescents convicted of murder. From this sample, 11 adolescents who murdered a member of their family were chosen for in-depth examination. All participants were convicted as an adult for murder and received a prison sentence. Characteristics of the crimes were explored, including demographic information, relationship to victim, motive, and weapon used in the commission of the crime. Additionally, DSM diagnosis information was available for some participants. A majority of the homicides (N = 8) were committed with a gun that was available in the home. More than half of the subjects murdered a parent or parental figure and the most salient characteristic was the presence of a chaotic family life prior to the homicide. No single motive was dominant, indicating that intrafamilial homicide is the culmination of a number of factors, including abuse and psychopathology. Based on the findings, recommendations are provided to address the needs of youth who are at risk for committing violent crimes such as intrafamilial homicide.