Auroral ionospheric plasma flow extraction using subsonic retarding potential analyzers.

Thermal ion retarding potential analyzers (RPAs) are used to measure in situ auroral ionospheric plasma parameters. This article analyzes data from a low-resource RPA in order to quantify the capability of the sensor. The RPA collects a sigmoidal current-voltage (I-V) curve, which depends on a non-linear combination of Maxwellian plasma parameters, so a forward-modeling procedure is used to match the best choice plasma parameters for each I-V curve. First, the procedure is used, given constraining information about the flow moment, to find scalar plasma parameters-ion temperature, ion density, and spacecraft sheath potential-for a single I-V curve interpreted in the context of a Maxwellian plasma distribution. Second, two azimuthally separated I-V curves from a single sensor on the spinning spacecraft are matched, given constraining information on density and sheath potential, to determine the bulk plasma flow components. These flows are compared to a high-fidelity, high-resource flow diagnostic. In both cases, the procedure's sensitivity to variations in constraining diagnostics is tested to ensure that the matching procedure is robust. Finally, a standalone analysis is shown, providing plasma scalar and flow parameters using known payload velocity and International Reference Ionosphere density as input information. The results show that the sensor can determine scalar plasma measurements as designed, as well as determine plasma DC flows to within hundreds of m/s error compared to a high-fidelity metric, thus showing their capability to replace higher-resource methods for determining DC plasma flows when coarse-resolution measurements at in situ spatial scales are suitable.

Low energy stable plasma calibration facility.

We have designed and fabricated a low energy plasma calibration facility for testing and calibration of rocket-borne charged-particle detectors and for the investigation of plasma sheath formation in an environment with ionospheric plasma energies, densities, and Debye lengths. We describe the vacuum system and associated plasma source, which was modified from a Naval Research Laboratory design [Bowles et al. Rev. Sci. Instrum. 67, 455 (1996)]. Mechanical and electrical modifications to this cylindrical microwave resonant source are outlined together with a different method of operating the magnetron that achieves a stable discharge. This facility produces unmagnetized plasmas with densities from 1x10(3)/cm(3) to 6x10(5)/cm(3), electron temperatures from 0.1 to 1.7 eV, and plasma potentials from 0.5 to 8 V depending on varying input microwave power and neutral gas flow. For the range of input microwave power explored (350-600 W), the energy density of the plasma remains constant because of an inverse relationship between density and temperature. This relationship allows a wide range of Debye lengths (0.3-8.4 cm) to be investigated, which is ideal for simulating the ionospheric plasma sheaths we explore.

A small spacecraft for multipoint measurement of ionospheric plasma.

Measurement of ionospheric plasma is often performed by a single in situ device or remotely using cameras and radar. This article describes a small, low-resource, deployed spacecraft used as part of a local, multipoint measurement network. A B-field aligned sounding rocket ejects four of these spin-stabilized spacecraft in a cross pattern. In this application, each spacecraft carries two retarding potential analyzers which are used to determine plasma density, flow, and ion temperature. An inertial measurement unit and a light-emitting diode array are used to determine the position and orientation of the devices after deployment. The design of this spacecraft is first described, and then results from a recent test flight are discussed. This flight demonstrated the successful operation of the deployment mechanism and telemetry systems, provided some preliminary plasma measurements in a simple mid-latitude environment, and revealed several design issues.

Including sheath effects in the interpretation of planar retarding potential analyzer's low-energy ion data.

The interpretation of planar retarding potential analyzers (RPA) during ionospheric sounding rocket missions requires modeling the thick 3D plasma sheath. This paper overviews the theory of RPAs with an emphasis placed on the impact of the sheath on current-voltage (I-V) curves. It then describes the Petite Ion Probe (PIP) which has been designed to function in this difficult regime. The data analysis procedure for this instrument is discussed in detail. Data analysis begins by modeling the sheath with the Spacecraft Plasma Interaction System (SPIS), a particle-in-cell code. Test particles are traced through the sheath and detector to determine the detector's response. A training set is constructed from these simulated curves for a support vector regression analysis which relates the properties of the I-V curve to the properties of the plasma. The first in situ use of the PIPs occurred during the MICA sounding rocket mission which launched from Poker Flat, Alaska in February of 2012. These data are presented as a case study, providing valuable cross-instrument comparisons. A heritage top-hat thermal ion electrostatic analyzer, called the HT, and a multi-needle Langmuir probe have been used to validate both the PIPs and the data analysis method. Compared to the HT, the PIP ion temperature measurements agree with a root-mean-square error of 0.023 eV. These two instruments agree on the parallel-to-B plasma flow velocity with a root-mean-square error of 130 m/s. The PIP with its field of view aligned perpendicular-to-B provided a density measurement with an 11% error compared to the multi-needle Langmuir Probe. Higher error in the other PIP's density measurement is likely due to simplifications in the SPIS model geometry.

Mesalazine (Mesasal/Claversal) 1.5 g b.d. vs. placebo in the maintenance of remission of patients with Crohn's disease.

UNLABELLED: INVESTIGATORS: This multicentre study was conducted by 29 principal investigators in 11 countries. AIMS: To compare the safety and efficacy of oral mesalazine (Mesasal/Claversal, 5-ASA) 1.5 g b.d. in comparison with placebo in the maintenance of remission in 286 patients with Crohn's disease. MATERIALS AND METHODS: Patients had to score less than 150 in their Crohn's Disease Activity Index (CDAI), and had to have had one period of clinical activity (CDAI > 150) within 18 months of the study start. Patients were randomized to receive 5-ASA 1.5 g b.d. daily or matching placebo for 12 months. Study visits were scheduled for months 1, 3, 6, 9 and 12, or when symptoms suggested a relapse of the disease. Relapse was defined as a CDAI score greater than 150, with at least a 60-point increase from the baseline index score. None of the patients used glucocorticoids or immunosuppressants during the trial. RESULTS: In the first group, 207 patients with Crohn's colitis or ileocolitis were randomized: there were 101 females and 106 males, in age range 18-71 years. A total of 106 patients (51 in the 5-ASA group and 55 in the placebo group) were withdrawn from the study due to adverse events, insufficient therapeutic effect, or for other reasons. This left 101 patients (51 in the 5-ASA group and 50 in the placebo group) who completed the 12-month trial. In the second group, 79 patients with Crohn's ileitis were randomized to treatment. There were 53 females and 26 males, age range 18-66 years. A total of 41 patients (19 in the 5-ASA group and 22 in the placebo group) were withdrawn from the study. This left 38 patients (17 in the 5-ASA group and 21 in the placebo group) who completed the 12-month trial. The primary efficacy variable was the CDAI. A protocol-eligible analysis and an intent-to-treat analysis were performed. No statistical differences were noted between the two analyses. In patients with Crohn's colitis or ileocolitis, or in those with ileitis, no statistically significant differences were noted with respect to the relapse rates between the 5-ASA and the placebo treatment groups. Adverse events in the gastrointestinal system were the most frequently reported in both treatment groups. Many of the events such as diarrhoea or abdominal pain are symptoms of Crohn's disease. The majority of the events reported were mild or moderate in severity. In neither study was the prevalence of adverse events or the proportion of drop-outs different between patients in the treatment or in the placebo groups. The site of the Crohn's disease had no effect on the frequency of adverse events. CONCLUSION: The relapse rates of Crohn's disease were similar for up to 12 months in both the 5-ASA 1.5 g b.d. and the placebo treatment groups.

Guanfacine treatment of comorbid attention-deficit hyperactivity disorder and Tourette's syndrome: preliminary clinical experience.

OBJECTIVE: Many children with Tourette's syndrome (TS) are handicapped more by difficulties with inattention, impulsivity, and hyperactivity than by their tics. However, stimulant medications used to treat attention-deficit hyperactivity disorder (ADHD) can exacerbate tics. Guanfacine is an alpha 2-adrenergic agonist that may have beneficial effects on attention, without the hypotensive or sedative effects of clonidine, which is often used as an alternative to stimulants. METHOD: An open-label study of guanfacine was performed in 10 children with TS+ADHD, aged 8 to 16 years. The duration of follow-up was 4 to 20 weeks, and the majority of subjects were treated with 1.5 mg/day. Ratings of tic severity and ADHD symptoms were obtained using the Yale Global Tic Severity Scale (YGTSS), the Tic Symptom Self Report (TSSR), and the Conners Parent Rating Scale. In addition, blind Continuous Performance Tests (CPTs) were performed at baseline and at two follow-up intervals in eight subjects. RESULTS: Guanfacine was associated with significant decreases in both commission errors (p < .02) and omission errors (p < .01) on the CPT. In addition, guanfacine caused a significant decrease in severity of motor (p < .02) and phonic (p < .02) tics as measured by the TSSR and the YGTSS, respectively. The most common side effects were transient sedation and headaches. CONCLUSION: Guanfacine may provide a safe alternative therapy for children with ADHD in the presence of tics. Future double-blind, controlled trials should be undertaken.

Risperidone treatment of children and adolescents with chronic tic disorders: a preliminary report.

OBJECTIVE: The purpose of this trial was to investigate the short-term safety and efficacy of risperidone in the treatment of chronic tic disorders in children and adolescents. METHOD: This was an 11-week open-label trial and included seven subjects (five boys and two girls) with a mean age of 12.9 +/- 1.9 years. The sample included five patients with Tourette's syndrome and two with chronic motor tic disorder. The children were seen at baseline and for two follow-up visits. Three children had a comorbid diagnosis of obsessive-compulsive disorder (OCD). RESULTS: Clinical response, as measured by the Yale Global Tic Severity Scale and the Children's version of the Yale-Brown Obsessive Compulsive Scale, revealed a statistically significant reduction in tic scores ranging from 26% [corrected] to 66%. One of three children with comorbid OCD showed substantial improvement; the other two subjects showed no change. The most frequent side effect was weight gain, which ranged from 8 to 14 lb. CONCLUSIONS: Risperidone, a neuroleptic with both serotonin- and dopamine-blocking properties, appears to be effective in reducing tic frequency and intensity in children and adolescents with chronic tic disorders.

Behavioral therapy in children and adolescents with obsessive-compulsive disorder: a pilot study.

Despite advances in pharmacotherapy for obsessive-compulsive disorder (OCD), medication treatments are not always effective. This pilot project examined the feasibility of a structured behavioral therapy program in the treatment of children and adolescents with OCD. Ten subjects with a primary diagnosis of OCD were invited to participate in the treatment program. Seven youngsters, 5 boys and 2 girls (age range 10.8-15.8, mean 13.0 years), participated and were treated for a mean of 14 sessions. These 7 subjects showed a broad range of OCD severity, as measured by the Children's Yale-Brown Obsessive Compulsive Scale (CYBOCS score range 12-29). Five subjects were also receiving antiobsessional medication (dose was not changed during the trial), and 2 subjects were treated without medication. All 7 youngsters showed a clinically significant reduction in the CYBOCS score at treatment endpoint (mean change 61%, range 30%-90%, effect size 2.04, p < 0.05), and the therapeutic gains were stable for at least 3 months after treatment. One of 5 children who had been receiving concurrent antiobsessional medication was able to tolerate a dose reduction following behavioral treatment. Two to three booster sessions within 6 months posttreatment were effective in preventing relapse in 4 of 6 subjects. The 3 children who declined behavioral treatment showed no improvement at 3-month and 6-month follow-up. Behavioral treatment appeared to be a useful adjunct to medication in children and adolescents with OCD. Further research could evaluate whether behavioral treatment would lower the dose requirements for children receiving antiobsessional medications. Randomized clinical trials are also needed to confirm the effectiveness of behavioral therapy alone or in combination with medication.

Clomipramine and obsessive-compulsive disorder.

Clomipramine is a tricyclic antidepressant that was the first effective agent in the treatment of OCD. Its capacity to block serotonin reuptake appears to be essential to reducing the primary symptoms of OCD. Like other tricyclic agents, CMI has an array of possible side effects including gastrointestinal, autonomic, hepatic, and cardiac problems that need to be considered in the clinical management of children and adolescents treated with CMI. Evaluation of clinical response begins with the identification of target symptoms and monitoring the change in these target symptoms over time. This effort can be aided by the use of clinical rating instruments such as the Children's Yale-Brown Obsessive Compulsive Scales and, to a limited degree, drug plasma levels. Although many OCD patients manifest a positive response to CMI, some patients do not. This variation suggests that other neurochemical systems may be implicated in OCD.

Environmental exposures and respiratory morbidity among very low birth weight infants at 1 year of life.

INTRODUCTION: Preterm infants have a substantially increased risk of developing respiratory illnesses. The goal of this study was to consider the impact of modifiable postnatal exposures on respiratory morbidity among a cohort of very low birth weight (VLBW) infants. OBJECTIVES: (1) Assess the rates of respiratory morbidity and exposure to indoor respiratory triggers in a population of VLBW infants at 1 year; (2) determine the association between exposures and respiratory morbidity. METHODS: We enrolled 124 VLBW infants into a prospective cohort study. Parents were called at 1 year to assess respiratory outcomes and environmental exposures. We used bivariate and multivariate analyses to assess the relationship between environmental exposures and acute care for respiratory illnesses. RESULTS: At 1 year, 9% of infants had physician-diagnosed asthma, 47% required >or=1 acute visit and 11% required hospitalisation for respiratory illness. The majority of infants (82%) were exposed to at least one indoor respiratory trigger. Infants living with a smoker (61% vs 40%) and infants exposed to pests (62% vs 39%) were more likely than unexposed infants to require acute care for respiratory problems. In a multivariate regression controlling for demographics, birth weight, bronchopulmonary dysplasia, and family history of asthma or allergies, both living with a smoker (OR 2.62; CI 1.09 to 6.29) and exposure to pests (OR 4.41; CI 1.22 to 15.94) were independently associated with the need for acute care for respiratory illnesses. CONCLUSIONS: In this sample, respiratory morbidity and exposure to triggers were common. VLBW infants may benefit from interventions that decrease exposure to respiratory triggers.

Tourette syndrome: update and review.

Tourette Syndrome is a movement disorder of childhood onset, characterized by multiple motor and phonic tics. In addition to tics, some children exhibit repetitive habits and recurring thoughts, and others may manifest problems of inattention, impulsiveness, and hyperactivity. Over the past two decades there has been increased interest in Tourette Syndrome, because it provides a useful model for examining the interaction of genes and environment, as well as neurobiology and behavior. This article provides school nurses and nurses working in school-based clinics with a general review of Tourette Syndrome and associated disorders.