A Pluto-like radius and a high albedo for the dwarf planet Eris from an occultation.

The dwarf planet Eris is a trans-Neptunian object with an orbital eccentricity of 0.44, an inclination of 44 degrees and a surface composition very similar to that of Pluto. It resides at present at 95.7 astronomical units (1 AU is the Earth-Sun distance) from Earth, near its aphelion and more than three times farther than Pluto. Owing to this great distance, measuring its size or detecting a putative atmosphere is difficult. Here we report the observation of a multi-chord stellar occultation by Eris on 6 November 2010 UT. The event is consistent with a spherical shape for Eris, with radius 1,163 ± 6 kilometres, density 2.52 ± 0.05 grams per cm(3) and a high visible geometric albedo, Pv = 0.96(+0.09)(-0.04). No nitrogen, argon or methane atmospheres are detected with surface pressure larger than ∼1 nanobar, about 10,000 times more tenuous than Pluto's present atmosphere. As Pluto's radius is estimated to be between 1,150 and 1,200 kilometres, Eris appears as a Pluto twin, with a bright surface possibly caused by a collapsed atmosphere, owing to its cold environment. We anticipate that this atmosphere may periodically sublimate as Eris approaches its perihelion, at 37.8 astronomical units from the Sun.

Supervisory control strategies for the new WWTP of Galindo-Bilbao: the long run from the conceptual design to the full-scale experimental validation.

This paper presents the theoretical basis and the main results obtained during the development and full-scale experimental validation of the new supervisory control strategy designed for the Galindo-Bilbao wastewater treatment plant (WWTP). The different phases of the project have been carried out over the last 8 years, combining model simulations, pilot-plant experimentation and full-scale validation. The final control strategy combines three complementary control loops to optimise the nitrogen removal in pre-denitrifying activated sludge plants. The first controller was designed to maintain the average concentration of the ammonia in the effluent via the automatic selection of the most appropriate DO set point in the aerobic reactors. The second control loop optimises the use of the denitrification potential and finally, the third control loop maintains the selected amount of biomass in the biological reactors by automatic manipulation of the wastage rate. Mobile-averaged windows have been implemented to incorporate commonly used averaged values in the control objectives. The performance of the controllers has been successfully assessed through the full-scale experimental validation in one of the lines of the WWTP.

A comparison of five rapid direct toxicity assessment methods to determine toxicity of pollutants to activated sludge.

Five rapid direct toxicity assessment methods were used in three European partner countries to determine the toxicity of single toxicants, mixed toxicants and real industrial wastes. The final aim was to protect microbial degradation of organic wastes in biological treatment processes and hence enhance the quality of treated effluents to be discharged to the environment. Nitrification inhibition, Respirometry, Adenosine triphosphate luminescence and Enzyme inhibition were tested utilising activated sludge as the testing matrix. The Vibrio fischeri toxicity test was used as a surrogate to compare the various microbial bioassays. The IC50 (toxicant concentration eliciting a 50% inhibitory effect) was determined for a number of pollutants including single toxicants Cd, Cr, Cu, Zn, 3,5-dichlorophenol, toluene and linear alkylbenzenesulphonate (LAS); a standard mixture of metals and LAS; a standard mixture of organics and LAS, and 16 industrial effluents. The V. fischeri bioassay was also chosen in order to assess quality control of toxicant preparation during testing in the different laboratories of the partner countries. Comparisons of sensitivity, cost of implementation, cost per test, relevance, and ease of use were made. The most sensitive bioassays were V. fischeri and Nitrification inhibition, however, this depended in the main on the pollutant and mixtures tested. It is recommended that during assessment of wastewater toxicity a suite of tests be used rather than reliance on one particular test.

Evaluation of nitrification-inhibition measurements.

A screening method for nitrification-inhibition determination has been evaluated at two laboratories, one in Sweden and one in Spain. Allyl-thiourea (ATU), methanol, chromium and zinc were used as reference toxicants in combination with different kinds of full-scale sludge and sludge produced in the laboratory. Different results were obtained with different combinations of activated sludge and toxicants. It was found that activated sludge often exposed to small amounts of a variety of toxic substances may build up a general resistance to toxic substances. Specific adaptation to certain substances was also observed. Domestic activated sludge responded in the same way to ATU regardless of whether it originated from Sweden or Spain. Synthetic sludge and domestic sludge exhibited the same inhibition of nitrification when tested with ATU as a toxicant. Synthetic activated sludge from two laboratory-scale plants run in parallel did not exhibit exactly the same sensitivity to certain toxicants. The variation in repeated tests with the synthetic sludges was about the same as for repeated tests with full-scale sludge and for other biological toxicity tests. Limits of detection were calculated to be about 5% for a single sample with three blanks as references at both the laboratories.

Learned activation of thoracic inspiratory muscles in tetraplegics.

The aim of this study was to determine whether tetraplegics can learn to activate accessory inspiratory muscles of the upper rib cage, and how this learning affects respiratory motion. Ten tetraplegics with lesional levels ranging from C5 to C7 were trained to increase the upper rib cage expansion during nine 20-min sessions. They were shown an electromyogram (EMG) feedback of the inspiratory muscles of the upper thorax and a signal indicating their current breathing phase (inspiration or expiration). The subjects were instructed to increase EMG during inspiration and to decrease it during expiration. Analysis of variance with session and respiratory phase as factors showed that the subjects progressively learned to increase inspiratory EMG. Thoracic motion, tidal volume and minute ventilation were correlated with inspiratory EMG and tended to increase as a function of practice. These preliminary results lend some support to the clinical use of EMG feedback in breathing therapy aimed at increasing thoracic motion and preventing or reducing paradoxical breathing in tetraplegics.

Electromyographic feedback for learning to activate thoracic inspiratory muscles.

The utility of EMG feedback for modifying the muscular pattern of breathing was investigated in twenty-four subjects divided into two groups (feedback, no feedback. Each took part in three 20-min training sessions, 24 h apart. All the subjects were instructed to increase the thoracic contribution of inspired gas. The feedback subjects were shown an EMG signal of the inspiratory muscles of the upper thorax and a signal indicating their current breathing phase (inspiration or expiration). The no feedback subjects only saw the breathing phase signal. The subjects' ability to control muscular activity was assessed as the relative increase in EMG from expiration to the subsequent inspiration. Analysis of variance with group and session as factors showed that feedback subjects performed significantly better, although the improvement in performance over the sessions by the two groups was not significantly different. These results lend some support to the clinical use of EMG feedback in breathing therapy aimed at changing the thoracoabdominal distribution of ventilation. However, further research for improving learning is necessary.

Randomized trial of a program to enhance the competencies of children with epilepsy.

A randomized, controlled trial was conducted in Santiago, Chile to test the impact of a child-centered, family-focused educational program for children aged 7-14 years with epilepsy and for their parents. The objectives of the program developed and pilot-tested in Los Angeles, California were to increase the children's knowledge, perceptions of competency, and skills related to dealing with seizures. Children in the experimental group (n = 123) and their parents separately attended four 1 1/2-h sessions and then met together at the end of each session to share learning experiences. Control children (n = 113) and their parents attended three 2-h sessions with a traditional lecture followed by question-and-answer format. All participants were pretested and then retested 5 months after completion of the educational intervention. Although there was some knowledge increase among children in the control group, the knowledge of children in the experimental group was significantly enhanced in a variety of areas related to management of their seizures and unnecessary restriction of their social and play activities. There was a significant increase in the self-perceptions of social competency of children in the experimental group. Children in the experimental group without serious behavioral problems also reported significantly better behavior after the intervention than did control children. There was no impact on children's disclosure of their diagnosis to friends and others.

ACT-asthma control y tratamiento para niños: a progress report.

A randomized clinical trial is in progress to evaluate an asthma educational program for Latino children and their parents. The intervention, "ACT-Asma Control y Tratamiento Para Niños," was adapted from ACT for Kids, an asthma self-management program for English-speaking families. Results of a pilot study indicated that socioeconomic status was a critical variable to be considered in the design of such programs. Latino children and parents encounter significant barriers to access and continuity of medical care. Therefore, the intervention was redesigned to include "linkages" using a nurse to reduce barriers and to coordinate care. The lesson plans emphasize concrete, experimental learning experiences, with repetition of key points in each session.

A randomized trial of A.C.T. (asthma care training) for kids.

A randomized control trial of a curriculum, A.C.T. (Asthma Care Training) for Kids, was conducted. Seventy-six children between the ages of 8 and 12 years, whose asthma required treatment with medications at least 25% of the days per month, were randomly assigned to control and experimental groups. The control group received 4 1/2 hours of lecture presentations on asthma and its management. The experimental groups (consisting of four to seven children and their parents) received five 1-hour sessions comprising "the treatment." Children and their parents were interviewed before the sessions and 3, 6, and 12 months after the completion of the experimental treatment. Use of emergency rooms and hospitals was determined by reviewing the records of these patients (all members of the Los Angeles Kaiser Permanente health care system) for the period of 1 year before and 1 year after the treatment. Results include (1) equivalent increases in knowledge and changes in beliefs in both groups, (2) significant changes in the self-reported compliance behaviors of the experimental group only, and (3) significant reductions in emergency room visits and days of hospitalization among those receiving the experimental treatment, compared with the control group. These changes represent an estimated savings of approximately $180 per child per year for those in the experimental group.