Eleketroencefalografski pokazatelji za vrijeme anestezije propofolom i ksilazin-ketaminom u koza

The use of intravenous anaesthesia for short term surgical procedures in animal husbandry practices is increasing. However, information on the quality of an anaesthetic regime in goats has remained inadequate. Therefore, electroencephalographic studies were conducted on twelve apparently healthy adult female Barbari crossbred goats, aged 2 to 4 years, to assess the anaesthetic quality of a propofol and xylazine-ketamine combination. Quantitative analysis of EEG parameters [Total power, Median Frequency, Spectral Edge Frequency 90 (SEF-90) and Relative Power (RP) of different frequency bands delta (δ), theta (θ), alpha (α) and beta (β)] were assessed pre-experimentally (control), and at one, five, 10, 30 min, one hr, and two hr after intravenous propofol (4 mg/kg) and xylazine (0.05 mg/kg)-ketamine (4 mg/kg) administration. After propofol and xylazine-ketamine administration total power, RP-δ and θ increased significantly (P<0.05) while SEF 90, MF, RP-α and RP-β decreased. Most of the EEG changes were adequately depicted in vertex and parietal channels. Spectral analysis of EEG tracings suggested that propofol produced minimum anaesthetic stress and is a safer and better choice for short term anaesthesia in goats.U stočarskoj praksi se za kratkotrajne kirurške zahvate sve više primjenjuje intravenska anestezija. Nedostaju međutim podaci na temelju kojih bi se ustanovila kvaliteta anestezijskog protokola u koza. Kako bi se procijenila kvaliteta kombinacije anestetika propofola i ksilazin-ketamina, provedena je analiza elektoencefalografskih pokazatelja u 12 zdravih odraslih koza. Koze su bili križanci barbari pasmine u dobi od 2 do 4 godine. Kvantitativna analiza EEG pokazatelja (total power, median frequency, SEF-90, relative power delta-δ, theta-θ, alfa-α i beta-β frekvencijskih pojaseva) procijenjeni su prije pokusa (kontrolna skupina), te 1, 5, 10, 30 minuta, jedan sat i dva sata nakon intravenske primjene propofola (4 mg/kg) i ksilazin (0,05 mg/kg)-ketamina (4 mg/kg). Nakon primjene propofola i ksilazin-ketamina total power, te relative power-δ i relative power-θ znakovito su porasli (P < 0,05), dok su se SEF 90, median frequency, relative power-α i relative power-β snizili. Većina EEG promjena odgovarajuće je prikazana u verteksu i parijetalnim kanalima. Spektralna analiza EEG-a upućuje na to da propofol u anestezijskom protokolu uzrokuje minimalan stres te je, u usporedbi sa ksilazin-ketaminom, za kratkotrajnu anesteziju koza sigurniji i bolji izbor

Observatories of the Solar Corona and Active Regions (OSCAR)

Coronal Mass Ejections (CMEs) and Corotating Interaction Regions (CIRs) are major sources of magnetic storms on Earth and are therefore considered to be the most dangerous space weather events. The Observatories of Solar Corona and Active Regions (OSCAR) mission is designed to identify the 3D structure of coronal loops and to study the trigger mechanisms of CMEs in solar Active Regions (ARs) as well as their evolution and propagation processes in the inner heliosphere. It also aims to provide monitoring and forecasting of geo- effective CMEs and CIRs. OSCAR would contribute to significant advancements in the field of solar physics, improvements of the current CME prediction models, and provide data for reliable space weather forecasting. These objectives are achieved by utilising two spacecraft with identical instrumentation, located at a heliocentric orbital distance of 1 AU from the Sun. The spacecraft will be separated by an angle of 68° to provide optimum stereoscopic view of the solar corona. We study the feasibility of such a mission and propose a preliminary design for OSCAR

Erratum: A space weather mission concept: Observatories of the solar corona and active regions (oscar) (Journal of Space Weather and Space Climate (2015) 5 (A4) DOI: 10.1051/swsc/2015003)

In this erratum we acknowledge EASCO as one of the inspirational mission concepts that helped the development of our original mission concept OSCAR

Study and test of micro-channel plates used in the dual ion spectrometer of the MMS mission by NASA

The Magnetospheric Multiscale mission led by NASA has been designed to study the micro-physics of Magnetic Reconnection in Earth's magnetosphere by using four identical spacecrafts with instruments with high temporal and spatial resolutions. Among these instruments are the Dual Ion Spectrometers (DIS) engineered to measure the 3D distribution of ion flux in space. The detector assembly of the DIS consists of Micro-Channel Plates (MCP) mounted in Chevron configuration. Centre d'Etude Spatiale des Rayonnements (CESR), Toulouse is responsible for the provision and testing of all fifty MCP pairs for this mission. The goal of the work was to participate in the testing and characterization of the first prototype of the MCPs. It was achieved by understanding the working and characteristics of the MCPs in general and getting familiar with the detector assembly of the DIS i.e. the MCP pair and the detector circuit board in particular. To perform the testing, it was necessary to understand the testing system as well. These topics are described in this report along with the testing procedure and the data analysis. The testing procedure was developed eventually after facing several problems during the testing. MCP pair characteristics like pulse height distributions, gain, resistance and the MCP operating voltages for the mission were determined on analyzing the data. Crosstalk was found in the circuit board of the detector assembly and has also been discussed.Validerat; 20101217 (root

Galactic Cosmic Ray Exposure of Humans in Space - Influence of galactic cosmic ray models and shielding on dose calculations for low-Earth orbit and near-Earth interplanetary space

The radiation environment in space is one of the primary concerns for human spaceflight as it poses potential risk to astronauts’ health. Galactic Cosmic Rays (GCR), consisting of high-energy nuclei, are a major source of radiation exposure in space. As the number of people visiting space in low-Earth orbit is increasing and mankind prepares to go beyond, the issue of radiation protection against GCR thus becomes vitally important. The pre-flight assessment of radiation-related health risks is achieved by performing numerical simulations of the mission scenario to estimate the necessary radiation-dose quantities. This technique requires models describing the radiation spectra, the target and shield configurations, and additionally transport codes to simulate the passage of radiation through matter. The reliability of the calculated dose therefore depends on the accuracy of all these models. During the course of this PhD work, commonly used models describing the GCR spectra are evaluated for their accuracy for various time periods. The model spectra of nuclei, most relevant for space dosimetry, are compared with measurements from high-altitude balloon flights and space missions. The GCR models included in this work are CREME96, CREME2009, Burger-Usoskin, Badhwar-O’Neill2010, Badhwar-O’Neill2011, Matthiä-ACE/OULU and SPENVIS/ISO15390. The influence of using these different GCR models on the dose calculations is studied for a time period ranging over the last four decades. This is achieved by calculating the absorbed dose and dose equivalent rates in a spherical water phantom using the GEANT4 Monte-Carlo framework. Additionally, the influence of aluminium shielding of varying thicknesses (0.3 g/cm², 10 g/cm² and 40 g/cm²) on the dose is investigated for a time period ranging from 1997 to 2012. All these investigations are performed for near-Earth interplanetary space and the orbit of the International Space Station (ISS). Apart from examining these parameters the effective dose, being the baseline quantity for radiation-risk assessment, is estimated. The quantity is calculated for the end of the year 2009 when the highest GCR intensity since the dawn of human spaceflight era was observed. Further studies presented in the thesis include the relative contribution of particles with different energies to the total exposure and the comparison of calculated dose with the measurements conducted inside the ISS and in-transit to Mars by the MSL/RAD instrument

A ready-to-use galactic cosmic ray model

Galactic cosmic ray nuclei close to Earth are of great importance in different fields of research. By studying their intensity in near-Earth interplanetary space and modeling their modulation in the heliosphere it is possible to gain knowledge both about the structure of the heliosphere and the transport processes within. Additionally, secondary phenomena like cloud formation, ionization processes in the atmosphere, cosmogenic nuclide production and radiation exposure in space and at aviation altitudes are related to the intensity of the galactic cosmic rays and their modulation in the heliosphere. In order to improve the knowledge about these processes and underlying mechanisms it is often beneficial to perform numerical simulations. A necessary prerequisite for such simulations is a model describing the galactic cosmic ray intensities for all particle types and energies of importance. Several of these models exist in the literature. However, many of these do not provide essential characteristics like the description of heavier nuclei or it is difficult to associate them to recent or actual solar modulation conditions. In this work a model is presented which describes the galactic cosmic ray spectra of nuclei based on a single parameter. The values of this parameter for different solar modulation conditions are derived from measurements of the Advanced Composition Explorer (ACE) spacecraft and Oulu neutron monitor count rates. Comparing the galactic cosmic ray spectra predicted by the model to a comprehensive set of experimental data from literature shows very good agreement

Estimation of Galactic Cosmic Ray exposure inside and outside the Earth’s magnetosphere during the recent solar minimum between solar cycles 23 and 24

The evidently low solar activity observed between solar cycles 23 and 24 during the years 2008–2010 led to a substantial increase in the Galactic Cosmic Ray (GCR) intensity in comparison with preceding solar minima. As the GCRs consist of highly-ionizing charged particles having the potential to cause biological damage, they are a subject of concern for manned missions to space. With the enhanced particle fluxes observed between 2008 and 2010, it is reasonable to assume that the radiation exposure from GCR must have also increased to unusually high levels. In this paper, the GCR exposure outside and inside the Earth’s magnetosphere is numerically calculated for time periods starting from 1970 to the end of 2011 in order to investigate the increase in dose levels during the years 2008–2010 in comparison with the last three solar minima. The dose rates were calculated in a water sphere, used as a surrogate for the human body, either unshielded or surrounded by aluminium shielding of 0.3, 10 or 40 g/cm². By performing such a long-term analysis, it was estimated that the GCR exposure during the recent solar minimum was indeed the largest in comparison with previous minima and that the increase was more pronounced for locations outside the magnetosphere