Modelling physiology of haemodynamic adaptation in short-term microgravity exposure and orthostatic stress on Earth

Cardiovascular haemodynamics alters during posture changes and exposure to microgravity. Vascular auto-remodelling observed in subjects living in space environment causes them orthostatic intolerance when they return on Earth. In this study we modelled the human haemodynamics with focus on head and neck exposed to different hydrostatic pressures in supine, upright (head-up tilt), head-down tilt position, and microgravity environment by using a well-developed 1D-0D haemodynamic model. The model consists of two parts that simulates the arterial (1D) and brain-venous (0D) vascular tree. The cardiovascular system is built as a network of hydraulic resistances and capacitances to properly model physiological parameters like total peripheral resistance, and to calculate vascular pressure and the related flow rate at any branch of the tree. The model calculated 30.0 mmHg (30%), 7.1 mmHg (78%), 1.7 mmHg (38%) reduction in mean blood pressure, intracranial pressure and central venous pressure after posture change from supine to upright, respectively. The modelled brain drainage outflow percentage from internal jugular veins is 67% and 26% for supine and upright posture, while for head-down tilt and microgravity is 65% and 72%, respectively. The model confirmed the role of peripheral veins in regional blood redistribution during posture change from supine to upright and microgravity environment as hypothesized in literature. The model is able to reproduce the known haemodynamic effects of hydraulic pressure change and weightlessness. It also provides a virtual laboratory to examine the consequence of a wide range of orthostatic stresses on human haemodynamics

Hydrologic responses of the Zwalm catchment using the REW model: incorporating uncertainty of soil properties

International audienceThe research presented in this paper focuses on an application of a newly developed physically-based watershed model approach, which is called Representative Elementary Watershed (REW) approach. The study stressed the effects of uncertainty of input parameters on the watershed responses (i.e. simulated discharges). The approach was applied to the Zwalm catchment, which is an agriculture dominated watershed with a drainage area of 114.3 km2 located in East-Flanders, Belgium. Uncertainty analysis of the model parameters is limited to the saturated hydraulic conductivity because of its high influence on the watershed hydrologic behavior. The assessment of outputs uncertainty is performed using the Monte Carlo method. The ensemble statistical watershed responses and their uncertainties are calculated and compared with the measurements. The results show that the measured discharges are falling within the 95% confidence interval of the modeled discharge

A Gaia DR 2 and VLT/FLAMES search for new satellites of the LMC

A wealth of tiny galaxies populates the surroundings of the Milky Way. Some of these objects might have their origin as former satellites of the Large Magellanic Cloud. Examples of the importance of understanding how many systems are genuine satellites of the MW or the LMC are the implications that the number and mass function of satellites have for dark matter theories and the treatment of baryonic physics in simulations of structure formation. Here we aim at deriving the bulk motions and estimates of the internal velocity dispersion and metallicity properties in four recently discovered distant southern dwarf galaxy candidates, Columba I, Reticulum III, Phoenix II and Horologium II. We combine Gaia DR2 astrometric measurements, photometry and new FLAMES spectroscopic data in the region of the CaII triplet lines; such combination is essential for finding potential member stars in these low luminosity systems. We find very likely member stars in all four satellites and are able to determine (or place limits on) the systems bulk motions and average internal properties. The systems are found to be very metal-poor, in agreement with dwarf galaxies and dwarf galaxy candidates of similar luminosity. The only system that we can place firmly in the category of dwarf galaxies is Phx II, given its resolved large velocity dispersion ($9.5_{-4.4}^{+6.8}$ km/s) and intrinsic metallicity spread (0.33 dex). Also for Col I we measure a clear metallicity spread. The orbital pole of Phx II is well constrained and close to that of the LMC, suggesting a prior association. The uncertainty on the orbital poles of the other systems are presently very large, so that an association cannot be excluded, apart from Col I. Using the numbers of potential former satellites of the LMC identified here and in the literature, we obtain for the LMC a dark matter mass of M$_{200}=1.9_{-0.9}^{+1.3}\times10^{11}$ M$_\odot$.Comment: 16 pages, 11 figures, 4 tables, accepted for publication in A&

In vitro efficacy of fungal endophytes and silver pyrazolate against Raffaelea lauricola, causal agent of laurel wilt of avocado

The South Florida avocado industry is being severely impacted by laurel wilt disease. Laurel wilt disease of avocado is caused by the fungal pathogen, Raffaelea lauricola (RL) and is vectored by ambrosia beetle, Xyleborus glabratus. Treatments options are limited, economically not sustainable, and require reapplication fungicides every couple of years. There is a crucial need for developing multiple modes of control using novel biological and chemical agents. The ambrosia beetle associated pathogenic fungi are known to outcompete other microorganisms by taking advantage of ethanol produced by the pathogen and the stressed tree. Endophytes, which reside inside the host plant tissue are part of the plant microbiome represent source of new potential biological control agents. In this study, three ethanol tolerant endophytic fungal species, isolated from avocado bark, were evaluated using in vitro dual culture assay and colonization tube (packed with bark/sapwood shaving) against RL. The endophytic isolates Tricoderma crissum, Tricoderma simmonsii, Lasiodiplodia theobromae were found to be highly capable of suppressing the mycelial colony growth of RL. The results suggest that combined abilities of ethanol tolerance and competitive colonization can provide useful criteria for identifying potential biocontrol agents. In vitro anti-RL activity of silver pyrazolate compound was assessed in both agar and liquid medium. Silver pyrazolate at levels of 30 and 45 ppm were found to be highly effective against RL. Further in planta research is needed to study the effects of endophytic fungal isolates and silver pyrazolate to assess their potential as additional tools for management of laurel wilt

Plethysmography system to monitor the jugular venous pulse: A feasibility study

Cerebral venous outflow is investigated in the diagnosis of heart failure through the monitoring of jugular venous pulse, an indicator to assess cardiovascular diseases. The jugular venous pulse is a weak signal stemming from the lying internal jugular vein and often invasive methodolo-gies requiring surgery are mandatory to detect it. Jugular venous pulse can also be extrapolated via the ultrasound technique, but it requires a qualified healthcare operator to perform the exami-nation. In this work, a wireless, user-friendly, wearable device for plethysmography is developed to investigate the possibility of monitoring the jugular venous pulse non-invasively. The proposed device can monitor the jugular venous pulse and the electrocardiogram synchronously. To study the feasibility of using the proposed device to detect physiological variables, several measurements were carried out on healthy subjects by considering three different postures: supine, sitting, and upright. Data acquired in the experiment were properly filtered to highlight the cardiac oscillation and remove the breathing contribution, which causes a considerable shift in the amplitude of signals. To evaluate the proper functioning of the wearable device for plethysmography, a comparison with the ultrasound technique was carried out. As a satisfactory result, the acquired signals resemble the typical jugular venous pulse waveforms found in literature

Airspace effects on the yield and quality of ewe milk.

Abstract Three groups of 12 midlactating Comisana ewes were housed in separate rooms of the same building and assigned to treatments of low (LV, 4.1m 3 ), medium (MV, 5.6m 3 ), or high (HV, 7.3m 3 ) airspace/animal. The concentrations of airborne microorganisms in the experimental rooms were measured twice weekly at 0930 and 1630. Ewe milk yield was recorded daily. Individual milk samples were analyzed weekly for milk composition, coagulating properties, somatic cell concentration (SCC), and polymorphonuclear neutrophil leukocyte count (PMNLC), and fortnightly for bacteriological characteristics; samples with more than 10 6 somatic cells/ml were cultured for mastitis-related pathogens. The LV and MV treatments resulted in higher relative humidity and air concentrations of staphylococci than the HV treatment. Greater amounts of air mesophilic bacteria were also found in the LV than in the HV room. Ewes in the HV group gave greater yields of milk than those in the LV and MV groups. LV milk also had a lower casein content than HV milk. Significant interactions of treatment x time were found for milk protein and fat content as well as for clotting time and clot firmness, with LV milk having the poorest composition and deteriorated renneting ability during the last 3 wk of the trial. The HV ewes had lower SCC and PMNLC and psychrotroph counts in their milk than LV and MV ewes and smaller amounts of mesophilic bacteria and fecal coliforms than LV animals. Subclinical mastitis occurred in two ewes of the LV and one of the MV groups, while no cases were recorded in the HV group. Results suggest that airspace is a critical factor in dairy sheep housing and indicate that a volume allocation of less than 7m 3 /animal may adversely affect the performance and health of the lactating ewe

Metallicity profiles of Ultra Diffuse Galaxies in NIHAO simulations

Supernovae feedback driven expansion has proven to be a viable mechanism to explain the average properties of Ultra Diffuse Galaxies (UDGs) such as the sizes, colors, mass and internal kinematics. Here, we explore the origin of stellar metallicity gradients in feedback driven simulated UDGs from the NIHAO project and compare them with the observed distribution of metallicity gradients of both Local Group dwarfs as well as of the recently observed UDG DF44. Simulated UDGs display a large variety of metallicity profiles, showing flat to negative gradients, similarly to what is observed in LG dwarfs, while DF44 data suggest a flat to positive gradient. The variety of metallicity gradients in simulations is set by the interplay between the radius at which star formation occurs and the subsequent supernovae feedback driven stellar redistribution: rotation supported systems tend to have flat metallicity profiles while dispersion supported galaxies show negative and steep profiles. Our results suggest that UDGs are not peculiar in what regards their metallicity gradients, when compared to regular dwarfs. Desirably, a larger observational sample of UDGs' gradients shall be available in the future, in order to test our predictions.Comment: 13 pages, 6+3 figure

188W/188Re Generator System and Its Therapeutic Applications

The188Re radioisotope represents a useful radioisotope for the preparation of radiopharmaceuticals for therapeutic applications, particularly because of its favorable nuclear properties. The nuclide decay pattern is through the emission of a principle beta particle having 2.12 MeV maximum energy, which is enough to penetrate and destroy abnormal tissues, and principle gamma rays (Eγ=155 keV), which can efficiently be used for imaging and calculations of radiation dose.188Re may be conveniently produced by188W/188Re generator systems. The challenges related to the double neutron capture reaction route to provide only modest yield of the parent188W radionuclide indeed have been one of the major issues about the use of188Re in nuclear medicine. Since the specific activity of188W used in the generator is relatively low (<185 GBq/g), the elutedRe188O4-can have a low radioactive concentration, often ineffective for radiopharmaceutical preparation. However, several efficient postelution concentration techniques have been developed, which yield clinically usefulRe188O4-solutions. This review summarizes the technologies developed for the preparation of188W/188Re generators, postelution concentration of the188Re perrhenate eluate, and a brief discussion of new chemical strategies available for the very high yield preparation of188Re radiopharmaceuticals