Compassion fatigue and anxiety in critical care emergency nurses: In between efficiency and humanity.

OBJECTIVES: To determine the emotional impact of permanent proximity to trauma and death in the Emergency and ICU's nurses establishing prevalence of Compassionate Fatigue (burnout and Secondary Traumatic Stress) and anxiety. Analyze its relationship with sociodemographic, training, workplace and psychological variables. METHODS: Descriptive, cross-sectional and multicentre study. The validated ProQOL v. IV and STAI scales and an ad-hoc questionnaire with the variables of the second objective were used in 710 nurses from nine highly complex hospitals in Catalonia (Spain). RESULTS: In both units, the prevalence of professionals affected with high scores of burnout was higher than 20%, on Secondary Traumatic Stress was 30% and, 12% on anxiety. Each subscale was significantly associated with the intention to leave units and the career. 97% of participants stated that they needed to be trained in emotional management. CONCLUSION: The prevalence of burnout and Secondary Traumatic Stress were higher in our study than those offered in the reference literature in emergency and ICU nurses. The prevalence of each construct was individually related to the desire to leave work units and career. This fact, together with the participants' desire to be better trained in emotional management exposes the need to establish educational plans, as well as institutional measures to prevent and support nurses for Compassion Fatigue.

Fatiga por compasión y ansiedad en enfermeras de cuidados críticos y emergencias. Entre eficiencia y humanidad / Compassion fatigue and anxiety in critical care emergency nurses: In between efficiency and humanity

Objetivos: Determinar el impacto emocional de la proximidad al trauma y la muerte en enfermeras de urgencias y de UCI mediante las prevalencias de fatiga de compasión (burnout y estrés traumático secundario) y ansiedad. Analizar su relación con variables de tipo sociodemográfico, formativas, laborales y psicológicas. Método: Estudio descriptivo, transversal y multicéntrico. Se utilizaron las escalas validadas ProQOL v.IV y STAI y un cuestionario ad-hoc con las variables del segundo objetivo, en 710 enfermeras de nueve hospitales de alta complejidad de Cataluña (España). Resultados: En ambas unidades, la proporción de profesionales afectados en alto grado de burnout fue superior al 20%, al 30% en estrés traumático secundario y al 12% en ansiedad. Cada subescala se asoció con la intención de abandonar la unidad y la profesión. El 97% de participantes manifestaron que era necesario recibir formación en gestión emocional. Conclusiones: Las prevalencias de burnout y de estrés traumático secundario fueron superiores en nuestro estudio respecto a la literatura de referencia en las enfermeras de urgencias y en las de UCI. La prevalencia de cada constructo se relacionó individualmente con el deseo de abandono de las enfermeras de sus unidades y de su profesión. Este hecho, junto al deseo de recibir formación de los participantes, expone la necesidad de establecer planes formativos, así como medidas institucionales de prevención y apoyo para la fatiga por compasión.(AU)

Objectives: To determine the emotional impact of permanent proximity to trauma and death in the Emergency and ICU's nurses establishing prevalence of Compassionate Fatigue (burnout and secondary traumatic stress) and anxiety. Analyze its relationship with sociodemographic, training, workplace and psychological variables. Methods: Descriptive, cross-sectional and multicentre study. The validated ProQOL v.IV and STAI scales and an ad-hoc questionnaire with the variables of the second objective were used in 710 nurses from nine highly complex hospitals in Catalonia (Spain). Results: In both units, the prevalence of professionals affected with high scores of burnout was higher than 20%, on secondary traumatic stress was 30%, and 12% on anxiety. Each subscale was significantly associated with the intention to leave units and the career. 97% of participants stated that they needed to be trained in emotional management. Conclusion: The prevalence of burnout and secondary traumatic stress were higher in our study than those offered in the reference literature in emergency and ICU nurses. The prevalence of each construct was individually related to the desire to leave work units and career. This fact, together with the participants’ desire to be better trained in emotional management exposes the need to establish educational plans, as well as institutional measures to prevent and support nurses for Compassion Fatigue.(AU)

Alteraciones del olfato en el Covid-19, revisión de la evidencia e implicaciones en el manejo de la pandemia / Olfactory dysfunction in covid-19, a review of the evidence and implications for pandemic management

Existe debate sobre si las alteraciones en el olfato deberían considerarse un síntoma de infección por COVID-19, dadas las implicaciones en el manejo del propio síntoma, en la realización de pruebas diagnósticas y en la aplicación de medidas de aislamiento. Se realizó una revisión sistemática bibliográfica de los artículos indexados en PubMed sobre alteraciones del olfato en cuadros virales de vías respiratorias, con especial énfasis en el COVID-19. El objetivo principal fue encontrar evidencia de interés clínico que apoye la relación entre ansomia y COVID-19. Las alteraciones del olfato en procesos infecciosos de vías altas son frecuentes, en su mayoría responden a una causa obstructiva por edema de la mucosa nasal. Ocasionalmente aparece una disfunción olfatoria post-viral de tipo neurosensorial, de pronóstico variable. La evidencia acerca de la anosmia en pacientes con COVID-19 es muy limitada, correspondiente a un grado 5 o D del Centre for Evidence-Based Medicine. En acuerdo con las distintas sociedades médicas que han emitido comunicados al respecto, parece razonable aplicar medidas de aislamiento, higiene y distanciamiento social a los pacientes con alteraciones del olfato de reciente aparición como único síntoma, aunque se debería estudiar la utilidad de la realización de pruebas diagnósticas a este tipo de pacientes

There is debate as to whether olfactory dysfunction should be considered a symptom of COVID-19 infection, given the implications for managing thesymptom itself, for diagnostic testing, and for implementing isolation measures. We undertook a systematic literature review of the articles indexed in PubMed on olfactory disorders in viral respiratory tract conditions, with special emphasis on COVID-19. The main objective was to find evidence of clinical interest to support the relationship between anosmia and COVID-19. Olfactory disorders in upper respiratory tract infections are frequent, most caused by obstruction due to oedema of the nasal mucosa. Occasionally, post-viral sensorineural olfactory dysfunction occurs, with a variable prognosis. The evidence on anosmia in COVID-19 patients is extremely limited, corresponding to a level 5 or D of the Centre for Evidence-Based Medicine. According to the various medical societies that have issued reports on the subject, it seems reasonable to apply isolation, higiene and social distancing measures in patients with recent olfactory disorders as the only symptom, although the usefulness of diagnostic tests for this type of patient should be studied

Lossy chaotic electromagnetic reverberation chambers: Universal statistical behavior of the vectorial field.

The effective Hamiltonian formalism is extended to vectorial electromagnetic waves in order to describe statistical properties of the field in reverberation chambers. The latter are commonly used in electromagnetic compatibility tests. As a first step, the distribution of wave intensities in chaotic systems with varying opening in the weak coupling limit for scalar quantum waves is derived by means of random matrix theory. In this limit the only parameters are the modal overlap and the number of open channels. Using the extended effective Hamiltonian, we describe the intensity statistics of the vectorial electromagnetic eigenmodes of lossy reverberation chambers. Finally, the typical quantity of interest in such chambers, namely, the distribution of the electromagnetic response, is discussed. By determining the distribution of the phase rigidity, describing the coupling to the environment, using random matrix numerical data, we find good agreement between the theoretical prediction and numerical calculations of the response.

Experimental Width Shift Distribution: A Test of Nonorthogonality for Local and Global Perturbations.

The change of resonance widths in an open system under a perturbation of its interior has been recently introduced by Fyodorov and Savin [Phys. Rev. Lett. 108, 184101 (2012)] as a sensitive indicator of the nonorthogonality of resonance states. We experimentally study universal statistics of this quantity in weakly open two-dimensional microwave cavities and reverberation chambers realizing scalar and electromagnetic vector fields, respectively. We consider global as well as local perturbations, and also extend the theory to treat the latter case. The influence of the perturbation type on the width shift distribution is more pronounced for many-channel systems. We compare the theory to experimental results for one and two attached antennas and to numerical simulations with higher channel numbers, observing a good agreement in all cases.

Evaluation of a visual biofeedback on the postural control in Parkinson's disease.

OBJECTIVES: Both stabilization and orientation components of postural control are affected in Parkinson's disease (PD). These deficits are partly due to proprioceptive impairments, which frequently coexist with a visual dependence. This study aimed to evaluate if a visual biofeedback - i.e. real time anteroposterior trunk and head orientations indicated with a simplified avatar and represented in a head-mounted display - could improve the postural control of PD patients in response to a postural disturbance. The influence of focusing on one specific component of the postural control (stabilization or orientation) was also examined. METHODS: Seventeen medicated PD patients performed sequences of pull-tests, either with eyes open, eyes closed or visual biofeedback, crossed with the verbal instruction to focus either on the stabilization or on the vertical body orientation. Kinematics data were collected. RESULTS: Backward trunk tilts consequent to the pulls were unchanged across the different conditions. With eyes open and eyes closed, patients did not recover their initial vertical orientation by adopting a slightly tilted backward position. This bias disappeared with the visual biofeedback. Moreover, falls consecutive to the test were significantly less frequent with the visual biofeedback than in the two other visual conditions. These different orientation and stabilization parameters were not affected by the instruction. CONCLUSION: Unlike a verbal instruction, visualizing in real time their own body's geometry improved both components of postural control of PD patients. This provides evidences in PD about links between impaired vertical orientation, deficits in balance control, and contribution of supplementary sensory cues.

Comparative next-generation mapping of the Phytophthora infestans resistance gene Rpi-dlc2 in a European accession of Solanum dulcamara.

Phytophthora infestans, the causal agent of late blight, remains the main threat to potato production worldwide. Screening of 19 accessions of Solanum dulcamara with P. infestans isolate Ipo82001 in detached leaf assays revealed strong resistance in an individual belonging to accession A54750069-1. This plant was crossed with a susceptible genotype, and an F(1) population consisting of 63 individuals was obtained. This population segregated for resistance in 1:1 ratio, both in detached leaf assays and in an open-field experiment. Presence of the formerly mapped Rpi-dlc1 gene as the cause of the observed segregating resistance could be excluded. Subsequently, AFLP analyses using 128 primer combinations enabled identification of five markers linked to a novel resistance gene named Rpi-dlc2. AFLP markers did not show sequence similarity to the tomato and potato genomes, hampering comparative genetic positioning of the gene. For this reason we used next-generation mapping (NGM), an approach that exploits direct sequencing of DNA (in our case: cDNA) pools from bulked segregants to calculate the genetic distance between SNPs and the locus of interest. Plotting of these genetic distances on the tomato and potato genetic map and subsequent PCR-based marker analysis positioned the gene on chromosome 10, in a region overlapping with the Rpi-ber/ber1 and -ber2 loci from S. berthaultii. Pyramiding of Rpi-dlc2 and Rpi-dlc1 significantly increased resistance to P. infestans, compared with individuals containing only one of the genes, showing the usefulness of this strategy to enhance resistance against Phytophthora.

Block matching 3D random noise filtering for absorption optical projection tomography.

Absorption and emission optical projection tomography (OPT), alternatively referred to as optical computed tomography (optical-CT) and optical-emission computed tomography (optical-ECT), are recently developed three-dimensional imaging techniques with value for developmental biology and ex vivo gene expression studies. The techniques' principles are similar to the ones used for x-ray computed tomography and are based on the approximation of negligible light scattering in optically cleared samples. The optical clearing is achieved by a chemical procedure which aims at substituting the cellular fluids within the sample with a cell membranes' index matching solution. Once cleared the sample presents very low scattering and is then illuminated with a light collimated beam whose intensity is captured in transillumination mode by a CCD camera. Different projection images of the sample are subsequently obtained over a 360 degrees full rotation, and a standard backprojection algorithm can be used in a similar fashion as for x-ray tomography in order to obtain absorption maps. Because not all biological samples present significant absorption contrast, it is not always possible to obtain projections with a good signal-to-noise ratio, a condition necessary to achieve high-quality tomographic reconstructions. Such is the case for example, for early stage's embryos. In this work we demonstrate how, through the use of a random noise removal algorithm, the image quality of the reconstructions can be considerably improved even when the noise is strongly present in the acquired projections. Specifically, we implemented a block matching 3D (BM3D) filter applying it separately on each acquired transillumination projection before performing a complete three-dimensional tomographical reconstruction. To test the efficiency of the adopted filtering scheme, a phantom and a real biological sample were processed. In both cases, the BM3D filter led to a signal-to-noise ratio increment of over 30 dB on severe noise-affected reconstructions revealing original-noise-hidden-image details. These results show the utility of the BM3D approach for OPT under typical conditions of very low light absorption, suggesting its implementation as an efficient alternative to other filtering schemes such as for example the median filter.

Factores asociados a desnutrición en las personas mayores que acudena centros sanitarios y sociosanitarios / Factors associated to hyponutrition in elderly people attending health care and social-health care centers

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Some methods for human liquid and solid waste utilization in bioregenerative life-support systems.

Bioregenerative life-support systems (BLSS) are studied for developing the technology for a future biological life-support system for long-term manned space missions. Ways to utilize human liquid and solid wastes to increase the closure degree of BLSS were investigated. First, urine and faeces underwent oxidation by Kudenko's physicochemical method. The products were then used for root nutrition of wheat grown by the soil-like substrate culture method. Two means of eliminating sodium chloride, introduced into the irrigation solution together with the products of urine oxidation, were investigated. The first was based on routine electrodialysis of irrigation water at the end of wheat vegetation. Dialysis eliminated about 50% of Na from the solution. This desalinization was performed for nine vegetations. The second method was new: after wheat cultivation, the irrigation solution and the solution obtained by washing the substrate containing mineral elements not absorbed by the plants were used to grow salt-tolerant Salicornia europaea L. plants (saltwort). The above-ground biomass of this plant can be used as a food, and roots can be added to the soil-like substrate. Four consecutive wheat and Salicornia vegetations were cultivated. As a result of this wheat and Salicornia cultivation process, the soil-like substrate salinization by NaCl were considerably decreased.

[The effectiveness of training schemes in the treatment of acute coronary syndrome at health centers]. / Mejoría en la asistencia al síndrome coronario agudo en los centros de asistencia primaria mediante un plan de formación.

OBJECTIVE: A preliminary evaluation of the impact of a training program on pre-hospitalization care of acute coronary syndrome (ACS). DESIGN: A cross-sectional study. SETTING: Lleida Health Service area. PATIENTS: A total of 661 ACS cases were observed in the Intensive Medical Care Unit from January 1st 2002 to December 31st 2004. INTERVENTIONS: A training program for primary health care medical staff on the pre-hospitalization management of ACS from July 2003 to December 2006 in 29 health care centers was conducted. MAIN ENDPOINTS OF INTEREST: The evolution of 5 pre-hospitalization interventions, (acetylsalicylic acid, nitroglycerine, electrocardiogram, intravenous tube and intravenous morphine) throughout the study period was measured. RESULTS: It was noted during the study that those centers in which training programs were held had a clear increase in the use of the 5 pre-hospitalization interventions. Insertion of an intravenous line, administration of intravenous morphine and administration of acetylsalicylic acid were all observed to have multiplied their use 10, 8 and 3 times, respectively. CONCLUSIONS: A training scheme for general practitioners (GP) is essential to ensure appropriate care of patients with this condition.

Mejoría en la asistencia al síndrome coronario agudo en los centros de asistencia primaria mediante un plan de formación / The effectiveness of training schemes in the treatment of acute coronary syndrome at health centers

Objetivo. Evaluar preliminarmente el impacto de un programa de formación en la atención prehospitalaria al síndrome coronario agudo (SCA). Diseño. Estudio transversal. Ámbito. Área de Salud de Lleida. Pacientes. Seiscientos sesenta y un casos de SCA atendidos en un Servicio de Medicina Intensiva (SMI) del 1 de enero de 2002 al 31 de diciembre de 2004. Intervenciones. Se realizó un plan de formación para médicos de asistencia primaria sobre manejo prehospitalario del SCA entre julio de 2003 y diciembre de 2006 en 29 centros de salud. Principales variables de interés. Se midió la evolución de la prevalencia de aplicación de 5 medidas prehospitalarias (ácido acetilsalicílico, nitroglicerina, electrocardiograma, vía venosa y cloruro mórfico endovenoso) a lo largo del período de estudio. Resultados. En los centros con plan de formación finalizado se observó un incremento evidente en la aplicación de las 5 medidas prehospitalarias a lo largo del período de estudio. La apertura de una vía intravenosa, la administración de cloruro mórfico intravenoso y la administración de ácido acetilsalicílico multiplican su aplicación por 10, 8 y 3 respectivamente. Conclusiones. Un adecuado plan de formación permite mejorar la asistencia de estos pacientes por parte de los médicos de cabecera

Objective. A preliminary evaluation of the impact of a training program on pre-hospitalization care of acute coronary syndrome (ACS). Design. A cross-sectional study. Setting. Lleida Health Service area. Patients. A total of 661 ACS cases were observed in the Intensive Medical Care Unit from January 1st 2002 to December 31th 2004. Interventions. A training program for primary health care medical staff on the pre-hospitalization management of ACS from July 2003 to December 2006 in 29 health care centers was conducted. Main endpoints of interest. The evolution of 5 pre-hospitalization interventions, (acetylsalicylic acid, nitroglycerine, electrocardiogram, intravenous tube and intravenous morphine) throughout the study period was measured. Results. It was noted during the study that those centers in which training programs were held had a clear increase in the use of the 5 pre-hospitalization interventions. Insertion of an intravenous line, administration of intravenous morphine and administration of acetylsalicylic acid were all observed to have multiplied their use 10, 8 and 3 times, respectively. Conclusions. A training scheme for general practitioners (GP) is essential to ensure appropriate care of patients with this condition

[Total prosthetic knee and hip joint infection. Descriptive epidemiology, therapeutics and evolution in a secondary hospital during ten years]. / Infección de prótesis total de rodilla y cadera. Epidemiología descriptiva, terapéutica y evolución en un hospital de segundo nivel durante 10 años.

OBJECTIVE: Epidemiological description, retrospective in its classification, evolution and therapeutics of total prosthesis knee and hip infected among the arthoplasties made between 1st of January 1994 and 31st of December 2003 in our hospital. RESULTS: The global infection rate was 2.4% (confidence interval of 95% [CI 95%], 1.6%-3.2%) over 40 cases in 1,666 joint implants. The average age +/- standard deviation (SD) was 69.5 years old +/- 5.1 years, mainly in women (67.5%). The most common location was the knee, 31 cases (77.5%). In 90.0% of the patients the aetiology was identified: 64,0% were gram-positive cocci (plasmacoagulase-negative staphylococci, and Staphylococcus aureus); 14.0% were gram-negative bacilli and mixed flora (11.0%). Acute infections were found in most of the cases (45,0%). The joint replacement had a healing rate of 66.7% in the first replacement and of 83.3% in the second replacement. CONCLUSIONS: The gram-positive cocci are the main microorganisms in these infections. More extensive studies about multiple aspects are necessary to evaluate the effectiveness of the different surgical techniques, the new antibiotics and the combined antibiotic therapies.

Infección de prótesis total de rodilla y cadera. Epidemiología descriptiva, terapéutica y evolución en un hospital de segundo nivel durante 10 años / Total prosthetic knee and hip joint infection. Descriptive epidemiology, therapeutics and evolution in a secondary hospital during ten years

Objetivo: Descripción epidemiológica retrospectiva en su clasificación,evolución y terapéuticas de las prótesis totales de cadera y rodilla infectadas entre las artroplastias realizadas desde el 1 de enero de 1994 al 31 de diciembre del 2003 en nuestro hospital. Resultados: La tasa de infección global de artroplastias fue 2,4% (intervalo de confianza del 95% [IC 95%], 1,6% -3,2%) sobre 40 casos de 1666 implantes articulares. La media de edad ± desviación estándar (DE) fue de 69,5 ± 5,1 años, en su mayoría mujeres (67,5%). La localización más frecuente fue rodilla, 31 casos (77,5%). En un 90,0% de los enfermos se filió la etiología, siendo un 64,0% cocos grampositivos (Staphylococcus plasmocoagulasa negativos y S. aureus), un 13,0% bacilos gramnegativos y flora mixta (11,0%). Predominaron las infecciones agudas (45,0%). El recambio articular en un tiempo tuvo una curación del 66,7% frente a un 83,3% en recambio en 2 tiempos. Conclusiones: Los cocos gram positivos son los principales microrganismos en estas infecciones. Son necesarios estudios amplios multicéntricos para valorar la eficacia de las distintas técnicas quirúrgicas, los nuevos antibióticos y las terapias antibióticas combinadas

Objective: Epidemiological description, retrospective in its classification, evolution and therapeutics of total prosthesis knee and hip infected among the arthoplasties made between 1st of January 1994 and 31st of December 2003 in our hospital. Results: The global infection rate was 2.4% (confidence interval of 95% [CI 95%], 1.6%-3.2%) over 40 cases in 1,666 joint implants. The average age +/- standard deviation (SD) was 69.5 years old +/- 5.1 years, mainly in women (67.5%). The most common location was the knee, 31 cases (77.5%). In 90.0% of the patients the aetiology was identified: 64,0% were gram-positive cocci (plasmacoagulase-negative staphylococci, and Staphylococcus aureus); 14.0% were gram-negative bacilli and mixed flora (11.0%). Acute infections were found in most of the cases (45,0%). The joint replacement had a healing rate of 66.7% in the first replacement and of 83.3% in the second replacement. Conclusions: The gram-positive cocci are the main microorganisms in these infections. More extensive studies about multiple aspects are necessary to evaluate the effectiveness of the different surgical techniques, the new antibiotics and the combined antibiotic therapies

Synthesis of biomass and utilization of plants wastes in a physical model of biological life-support system.

The paper considers problems of biosynthesis of higher plants' biomass and "biological incineration" of plant wastes in a working physical model of biological LSS. The plant wastes are "biologically incinerated" in a special heterotrophic block involving Californian worms, mushrooms and straw. The block processes plant wastes (straw, haulms) to produce soil-like substrate (SLS) on which plants (wheat, radish) are grown. Gas exchange in such a system consists of respiratory gas exchange of SLS and photosynthesis and respiration of plants. Specifics of gas exchange dynamics of high plants--SLS complex has been considered. Relationship between such a gas exchange and PAR irradiance and age of plants has been established. Nitrogen and iron were found to the first to limit plants' growth on SLS when process conditions are deranged. The SLS microflora has been found to have different kinds of ammonifying and denitrifying bacteria which is indicative of intensive transformation of nitrogen-containing compounds. The number of physiological groups of microorganisms in SLS was, on the whole, steady. As a result, organic substances--products of exchange of plants and microorganisms were not accumulated in the medium, but mineralized and assimilated by the biocenosis. Experiments showed that the developed model of a man-made ecosystem realized complete utilization of plant wastes and involved them into the intrasystem turnover.

Identification of a metabolic network structure representative of Arthrospira (spirulina) platensis metabolism.

A comprehensive network structure for the autotrophic growth of Arthrospira platensis is proposed. The metabolic network was built up with 121 reactions and 134 metabolites including biomass synthesis, production of a growth-associated exopolysaccharide, and energy aspects. The model supports the existence of a metabolic shunt of PEP to pyruvate through PEP carboxylase, NAD(+)-dependent malate dehydrogenase and malic enzyme to convert NADH,H(+) into NADPH,H(+). A limit in Arthrospira growth metabolism due to NADH,H(+) balancing is evidenced, explaining why the maximal light-dependent mass yield of the growth-associated exopolysaccharide was 0.51 kg EPS kg(-1) biomass, consistent with experimental results.

Mass exchange in an experimental new-generation life support system model based on biological regeneration of environment.

An experimental model of a biological life support system was used to evaluate qualitative and quantitative parameters of the internal mass exchange. The photosynthesizing unit included the higher plant component (wheat and radish), and the heterotrophic unit consisted of a soil-like substrate, California worms, mushrooms and microbial microflora. The gas mass exchange involved evolution of oxygen by the photosynthesizing component and its uptake by the heterotroph component along with the formation and maintaining of the SLS structure, growth of mushrooms and California worms, human respiration, and some other processes. Human presence in the system in the form of "virtual human" that at regular intervals took part in the respirative gas exchange during the experiment. Experimental data demonstrated good oxygen/carbon dioxide balance, and the closure of the cycles of these gases was almost complete. The water cycle was nearly 100% closed. The main components in the water mass exchange were transpiration water and the watering solution with mineral elements. Human consumption of the edible plant biomass (grains and roots) was simulated by processing these products by a unique physicochemical method of oxidizing them to inorganic mineral compounds, which were then returned into the system and fully assimilated by the plants. The oxidation was achieved by "wet combustion" of organic biomass, using hydrogen peroxide following a special procedure, which does not require high temperature and pressure. Hydrogen peroxide is produced from the water inside the system. The closure of the cycle was estimated for individual elements and compounds. Stoichiometric proportions are given for the main components included in the experimental model of the system. Approaches to the mathematical modeling of the cycling processes are discussed, using the data of the experimental model. Nitrogen, as a representative of biogenic elements, shows an almost 100% closure of the cycle inside the system. The proposed experimental model of a biological system is discussed as a candidate for potential application in the investigations aimed at creating ecosystems with largely closed cycles of the internal mass exchange. The formation and maintenance of sustainable cycling of vitally important chemical elements and compounds in biological life support systems (BLSS) is an extremely pressing problem. To attain the stable functioning of biological life support systems (BLSS) and to maintain a high degree of closure of material cycles in than, it is essential to understand the character of mass exchange processes and stoichiometnc proportions of the initial and synthesized components of the system.

Light intensity and production parameters of phytocenoses cultivated on soil-like substrate under controlled [correction of controled] environment conditions.

To increase the degree of closure of biological life support systems of a new generation, we used vermicomposting to involve inedible phytomass in the intra-system mass exchange. The resulting product was a soil-like substrate, which was quite suitable for growing plants (Manukovsky et al. 1996, 1997). However, the soil like substrate can be regarded as a candidate for inclusion in a system only after a comprehensive examination of its physical, chemical, and other characteristics. An important criterion is the ability of the soil-like substrate to supply the necessary mineral elements to the photosynthesizing component under the chosen cultivation conditions. Thus, the purpose of this work was to study the feasibility of enhancing the production activity of wheat and radish crops by varying the intensity of photosynthetically active radiation, without decreasing the harvest index. The increase of light intensity from 920 to 1150 micromoles m-2 s-1 decreased the intensity of apparent photosynthesis of the wheat crops and slightly increased the apparent photosynthesis of the radish crops The maximum total and grain productivity (kg/m2) of the wheat crops was attained at the irradiance of 920 micromoles m-2 s-1. Light intensity of 1150 micromoles m-2 s-1 decreased the productivity of wheat plants and had no significant effect on the productivity of the radish crops (kg/m2) as compared to 920 micromoles m-2 s-1. The qualitative and quantitative composition of microflora of the watering solution and substrate was determined by the condition of plants, developmental phase and light intensity. By the end of wheat growth under 1150 micromoles m-2 s-1 the numbers of bacteria of the coliform family and phytopathogenic bacteria in the watering solution and substrate were an order of magnitude larger than under other illumination conditions. The obtained data suggest that the cultivation of plants in a life support system on soil-like substrate from composts has a number of advantages over the cultivation on neutral substrates, which require continual replenishment of the plant nutrient solution from the system's store to complement the macro- and micro-elements. Yet, a number of problems arise, including those related to the controlling of the production activity of the plants by the intensity of photosynthetically active radiation. It is essential to understand why the intensity of production processes is limited at higher irradiation levels and to overcome the factors responsible for this, so that the soil-like substrate could have an even better chance in the competition for the best plant cultivation technology to be used in biological life support systems.

Recycling efficiencies of C, H, O, N, S, and P elements in a Biological Life Support System based on microorganisms and higher plants.

MELiSSA is a microorganism based artificial ecosystem conceived as a tool for understanding the behavior of ecosystems and developing the technology for future Manned Space Missions. MELiSSA is composed of four compartments colonized by the microorganisms required by the function of this ecosystem : breakdown of waste produced by men, regeneration of atmosphere and biosynthesis of edible biomass. This paper reports the mass balance description of a Biological Life Support System composed of the MELiSSA loop and of a Higher Plant Compartment working in parallel with the photosynthetic Spirulina compartment producing edible biomass. The recycling efficiencies of the system are determined and compared for various working conditions of the MELiSSA loop with or without the HPC.