Inelastic and reactive scattering of hyperthermal atomic oxygen from amorphous carbon

The reaction of hyperthermal oxygen atoms with an amorphous carbon-13 surface was studied using a modified universal crossed molecular beams apparatus. Time-of-flight distributions of inelastically scattered O-atoms and reactively scattered CO-13 and CO2-13 were measured with a rotatable mass spectrometer detector. Two inelastic scattering channels were observed, corresponding to a direct inelastic process in which the scattered O-atoms retain 20 to 30 percent of their initial kinetic energy and to a trapping desorption process whereby O-atoms emerge from the surface at thermal velocities. Reactive scattering data imply the formation of two kinds of CO products, slow products whose translational energies are determined by the surface temperature and hyperthermal (Approx. 3 eV) products with translational energies comprising roughly 30 percent of the total available energy (E sub avl), where E sub avl is the sum of the collision energy and the reaction exothermicity. Angular data show that the hyperthermal CO is scattered preferentially in the specular direction. CO2 product was also observed, but at much lower intensities than CO and with only thermal velocities

Dependence of the Martian radiation environment on atmospheric depth: Modeling and measurement

The energetic particle environment on the Martian surface is influenced by solar and heliospheric modulation and changes in the local atmospheric pressure (or column depth). The Radiation Assessment Detector (RAD) on board the Mars Science Laboratory rover Curiosity on the surface of Mars has been measuring this effect for over four Earth years (about two Martian years). The anticorrelation between the recorded surface Galactic Cosmic Ray-induced dose rates and pressure changes has been investigated by Rafkin et al. (2014) and the long-term solar modulation has also been empirically analyzed and modeled by Guo et al. (2015). This paper employs the newly updated HZETRN2015 code to model the Martian atmospheric shielding effect on the accumulated dose rates and the change of this effect under different solar modulation and atmospheric conditions. The modeled results are compared with the most up-to-date (from 14 August 2012 to 29 June 2016) observations of the RAD instrument on the surface of Mars. Both model and measurements agree reasonably well and show the atmospheric shielding effect under weak solar modulation conditions and the decline of this effect as solar modulation becomes stronger. This result is important for better risk estimations of future human explorations to Mars under different heliospheric and Martian atmospheric conditions

Efectul fiziologic al tioureei asupra performanţelor biologice a plantelor în condiţii de secetă: I. Majorarea protecţiei antioxidante

The greenhouse experiments were conducted to evaluate the effect of grain presoaking and foliar application of cytokinin (CK), thiourea (TU) and combination (TU+C) - thiourea with Composite preparation (pat. MD 813) containing micronutrient, on the changes of antioxidant enzymes activities, photosynthesis and grain yield of maize plants under normal water content and drought stress conditions. Treated with TU and TU+C plants resulted in great increases in the activity of SOD, CAT, APX, GR. The higher antioxidant enzyme activity in pre-treated plants was associated with the lesser MDA. Positive physiological effects of TU and TU+C were confirmed by the higher level of assimilating pigments and photosynthesis. Concentration of carotenoids was affected by drought, but spraying with TU and TU+C alleviated drought effects. It was concluded that combined application of TU+C as seed treatment and foliar spray was more effective than cytokinin in improving the Zea mays performance

Experimental and simulation results of the adsorption of Mo and V onto ferrihydrite.

This study aims to highlight discrepancies between experimental and simulation linked to the mechanisms of Mo and V adsorption onto ferrihydrite (FHY) nanoparticles. We have measured adsorption capacities and uptake efficiencies and then fitted and compared these with outputs from various geochemical and adsorption models that were run as a function of pH, surface area (SA) and ferrihydrite particles size distributions. Our results revealed that the experimental data for the Mo system could be fitted very well, but this was not the case for the V system, when a model default value for the SA of FHY of 600 m2 g-1 was used. The discrepancy in the results for the V system can be explained by the lack of specific V species and/or associated constants in databases and variation in software versions, which change the outputted chemical species. Our comparative results also confirm that any experimental variables used as modelling inputs need to be checked carefully prior to any modelling exercises

Modeling the variations of Dose Rate measured by RAD during the first MSL Martian year: 2012-2014

The Radiation Assessment Detector (RAD), on board Mars Science Laboratory's (MSL) rover Curiosity, measures the {energy spectra} of both energetic charged and neutral particles along with the radiation dose rate at the surface of Mars. With these first-ever measurements on the Martian surface, RAD observed several effects influencing the galactic cosmic ray (GCR) induced surface radiation dose concurrently: [a] short-term diurnal variations of the Martian atmospheric pressure caused by daily thermal tides, [b] long-term seasonal pressure changes in the Martian atmosphere, and [c] the modulation of the primary GCR flux by the heliospheric magnetic field, which correlates with long-term solar activity and the rotation of the Sun. The RAD surface dose measurements, along with the surface pressure data and the solar modulation factor, are analysed and fitted to empirical models which quantitatively demonstrate} how the long-term influences ([b] and [c]) are related to the measured dose rates. {Correspondingly we can estimate dose rate and dose equivalents under different solar modulations and different atmospheric conditions, thus allowing empirical predictions of the Martian surface radiation environment

Laparoscopic management of associated abdominal complications of ventriculoperitoneal shunt

Catedra de chirurgie nr. 1 „Nicolae Anestiadi”, Laboratorul de chirurgie hepato-pancreato-biliară, USMF „Nicolae Testemițanu”, IMSP Institutul de Medicină Urgentă, Chișinău, Republica Moldova, Conferința stiințifică „Nicolae Anestiadi – nume etern al chirurgiei basarabene” consacrată centenarului de la nașterea profesorului Nicolae Anestiadi 26 august 2016Introducere. Complicaţiile abdominale ale şuntării ventriculoperitoneale (VP) sunt descrise în 5–47% cazuri. Pseudochistul abdominal cu lichid cerebrospinal este o complicaţie rară a şuntului VP, majoritatea fiind descrise la copii. Pseudochistul abdominal şi migrarea intraabdominală a cateterului sunt rare la pacienţii adulţi. Ocluzia şuntului VP sau nefuncţionarea acestuia induc presiune intracraniană sporită, fiind o indicaţie pentru intervenţie de urgenţă. Metode. Prezentare de caz clinic. Rezultate. Autorii prezintă un caz de tratament reuşit al unui pseudochist abdominal cu lichid cerebrospinal combinat cu migrarea cateterului intraabdominal rupt, la 9 ani după instalarea şuntului VP pentru hidrocefalie la o pacientă de 20 ani. Concluzii. Abordul laparoscopic este sigur şi util pentru tratamentul complicaţiilor combinate ale şuntului VP.Introduction. Abdominal complications after ventriculoperitoneal (VP) shunt placement are reported in 5–47% of cases. Abdominal cerebrospinal fluid (CSF) pseudocyst is an uncommon complication of a VP shunt, the majority being reported in children. Abdominal pseudocysts and intra-abdominal catheter migration are rare in adult patients. Ventriculoperitoneal shunt obstruction or malfunction results in elevated intracranial pressure, representing an indication for immediate intervention. Methods. Case report. Results. The authors report a case of successful laparoscopic management in a 20-year-old female patient who developed CSF pseudocyst combined with migration of the fractured catheter in the abdominal cavity nine years after VP shunting for hydrocephalus. Conclusions. Laparoscopic approach is a safe and useful treatment modality for combined peritoneal complications of VP shunt

Association testing by haplotype-sharing methods applicable to whole-genome analysis

We propose two new haplotype-sharing methods for identifying disease loci: the haplotype sharing statistic (HSS), which compares length of shared haplotypes between cases and controls, and the CROSS test, which tests whether a case and a control haplotype show less sharing than two random haplotypes. The significance of the HSS is determined using a variance estimate from the theory of U-statistics, whereas the significance of the CROSS test is estimated from a sequential randomization procedure. Both methods are fast and hence practical, even for whole-genome screens with high marker densities. We analyzed data sets of Problems 2 and 3 of Genetic Analysis Workshop 15 and compared HSS and CROSS to conventional association methods. Problem 2 provided a data set of 2300 single-nucleotide polymorphisms (SNPs) in a 10-Mb region of chromosome 18q, which had shown linkage evidence for rheumatoid arthritis. The CROSS test detected a significant association at approximately position 4407 kb. This was supported by single-marker association and HSS. The CROSS test outperformed them both with respect to significance level and signal-to-noise ratio. A 20-kb candidate region could be identified. Problem 3 provided a simulated 10 k SNP data set covering the whole genome. Three known candidate regions for rheumatoid arthritis were detected. Again, the CROSS test gave the most significant results. Furthermore, both the HSS and the CROSS showed better fine-mapping accuracy than straightforward haplotype association. In conclusion, haplotype sharing methods, particularly the CROSS test, show great promise for identifying disease gene loci