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We present the first observations of short large-amplitude magnetic structures (denoted SLAMS) at Mercury. We have investigated approximately 4 years of MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) data to identify SLAMS in the Mercury foreshock. Defining SLAMS as magnetic field compressional structures, with an increase in magnetic field strength of at least twice the background magnetic field strength, when MESSENGER is located in the solar wind, we find 435 SLAMS. The SLAMS are found either in regions of a general ultra-low frequency (ULF) wave field, at the boundary of such a ULF wave field, or in a few cases isolated from the wave field. We present statistics on several properties of the SLAMS, such as temporal scale size, amplitude, and the presence of whistler-like wave emissions. We find that SLAMS are mostly found during periods of low interplanetary magnetic field strength, indicating that they are more common for higher solar wind Alfvénic Mach number (MA). We use the Tao solar wind model to estimate solar wind parameters to verify that MA is indeed larger during SLAMS observations than otherwise. Finally, we also investigate how SLAMS observations are related to foreshock geometry. [ABSTRACT FROM AUTHOR]

Background: Prehospital anesthesia may lead to circulatory collapse after severe hemorrhage. It is possible that permissive hypoventilation, refraining from tracheal intubation and accepting spontaneous ventilation, decreases this risk, but it is not known if oxygen delivery can be maintained. We investigated the feasibility of permissive hypoventilation after class III hemorrhage and whole blood resuscitation in three prehospital phases: 15 min on‐scene, 30 min whole blood resuscitation, and 45 min after. Study Design and Methods: 19 crossbred swine, mean weight 58.5 kg, were anesthetized with ketamine/midazolam and hemorrhaged to a mean (SD) 1298 (220) mL (33%) and randomized to permissive hypoventilation (n = 9) or positive pressure ventilation with FiO2 21% (n = 10). Results: In permissive hypoventilation versus positive pressure ventilation, indexed oxygen delivery (DO2I) decreased to mean (SD) 4.73 (1.06) versus 3.70 (1.13) mL min−1 kg−1 after hemorrhage and increased to 8.62 (2.09) versus 6.70 (1.56) mL min−1 kg−1 at completion of resuscitation. DO2I, indexed oxygen consumption (VO2I), and arterial saturation (SaO2) did not differ. Permissive hypoventilation increased the respiratory rate and increased pCO2. Positive pressure ventilation did not deteriorate circulation. Cardiac index (CI), systolic arterial pressure (SAP), hemoglobin (Hb), and heart rate did not differ. Discussion: Permissive hypoventilation and positive pressure ventilation were equally effective to maintain oxygen delivery in all phases. A respiratory rate of 40 was feasible, showing no signs of respiratory fatigue for 90 min, indicating that whole blood resuscitation may be prioritized in select patients with severe hemorrhage and spontaneous breathing. [ABSTRACT FROM AUTHOR]

Background: Prehospital anesthesia may lead to circulatory collapse after severe hemorrhage. It is possible that permissive hypoventilation, refraining from tracheal intubation and accepting spontaneous ventilation, decreases this risk, but it is not known if oxygen delivery can be maintained. We investigated the feasibility of permissive hypoventilation after class III hemorrhage and whole blood resuscitation in three prehospital phases: 15 min on‐scene, 30 min whole blood resuscitation, and 45 min after. Study Design and Methods: 19 crossbred swine, mean weight 58.5 kg, were anesthetized with ketamine/midazolam and hemorrhaged to a mean (SD) 1298 (220) mL (33%) and randomized to permissive hypoventilation (n = 9) or positive pressure ventilation with FiO2 21% (n = 10). Results: In permissive hypoventilation versus positive pressure ventilation, indexed oxygen delivery (DO2I) decreased to mean (SD) 4.73 (1.06) versus 3.70 (1.13) mL min−1 kg−1 after hemorrhage and increased to 8.62 (2.09) versus 6.70 (1.56) mL min−1 kg−1 at completion of resuscitation. DO2I, indexed oxygen consumption (VO2I), and arterial saturation (SaO2) did not differ. Permissive hypoventilation increased the respiratory rate and increased pCO2. Positive pressure ventilation did not deteriorate circulation. Cardiac index (CI), systolic arterial pressure (SAP), hemoglobin (Hb), and heart rate did not differ. Discussion: Permissive hypoventilation and positive pressure ventilation were equally effective to maintain oxygen delivery in all phases. A respiratory rate of 40 was feasible, showing no signs of respiratory fatigue for 90 min, indicating that whole blood resuscitation may be prioritized in select patients with severe hemorrhage and spontaneous breathing. [ABSTRACT FROM AUTHOR]

We present the first statistical study on the velocity of magnetic holes (MHs) in the solar wind. Magnetic holes are localized depressions of the magnetic field, often divided into two classes: rotational and linear MHs. We have conducted a timing analysis of observations of MHs from the Cluster mission in the first quarter of 2005. In total, 69 events were used; out of these, there were 40 linear and 29 rotational MHs, where the limit of magnetic field rotation was set to 50 ∘. The resulting median velocity was 7.4 ± 45 and 25 ± 42 km s -1 for linear and rotational MHs, respectively. For both classes, around 70% of the events had a velocity in the solar wind frame that was lower than the Alfvén velocity. Therefore, we conclude that within the observational uncertainties, both linear and rotational MHs are convected with the solar wind. [ABSTRACT FROM AUTHOR]

High‐speed plasma jets downstream of Earth's bow shock are high velocity streams associated with a variety of shock and magnetospheric phenomena. In this work, using the Magnetosphere Multiscale mission, we study the properties of a jet found downstream of the Quasi‐parallel bow shock using high‐resolution (burst) data. By doing so, we demonstrate how the jet is an inherently kinetic structure described by highly variable velocity distributions. The observed distributions show the presence of two plasma population, a cold/fast jet and a hotter/slower background population. We derive partial moments for the jet population to isolate its properties. The resulting partial moments appear different from the full ones which are typically used in similar studies. These discrepancies show how jets are more similar to upstream solar wind beams compared to what was previously believed. Finally, we explore the consequences of our results and methodology regarding the characterization, origin, and evolution of jets. Plain Language Summary: Typically, particles from the Sun get strongly decelerated when they interact with the magnetic field of Earth, forming a shock wave. Magnetosheath (MSH) jets are fast streams of particles appearing downstream of this shock, with typically higher velocities and densities than the background population. In this work, we show how jets behave after they are created at the shock wave. We describe the variability of their properties and how this is connected to the background MSH population they interact with. Through that, we reveal new insights regarding their origin, evolution, and motivate on a new approach to study jets and similar phenomena in the future. Key Points: Ions in an observed jet exhibit complex distribution functions, with a cold/fast jet beam and hotter/slower background populationJet interaction with the background magnetosheath is studied by comparing partial moments of the jet population with the full ion momentsThe derived properties of the cold/fast population connect the jet's origin to upstream solar wind and foreshock structures [ABSTRACT FROM AUTHOR]

Solar wind magnetic holes are localized depressions of the magnetic field strength, on timescales of seconds to minutes. We use Cluster multipoint measurements to identify 26 magnetic holes which are observed just upstream of the bow shock and, a short time later, downstream in the magnetosheath, thus showing that they can penetrate the bow shock and enter the magnetosheath. For two magnetic holes, we show that the relation between upstream and downstream properties of the magnetic holes are well described by the MHD (magnetohydrodynamic) Rankine–Hugoniot (RH) jump conditions. We also present a small statistical investigation of the correlation between upstream and downstream observations of some properties of the magnetic holes. The temporal scale size and magnetic field rotation across the magnetic holes are very similar for the upstream and downstream observations, while the depth of the magnetic holes varies more. The results are consistent with the interpretation that magnetic holes in Earth's and Mercury's magnetosheath are of solar wind origin, as has previously been suggested. Since the solar wind magnetic holes can enter the magnetosheath, they may also interact with the magnetopause, representing a new type of localized solar wind–magnetosphere interaction. [ABSTRACT FROM AUTHOR]

We use Magnetosphere Multiscale (MMS) mission data to investigate a small number of magnetosheath jets, which are localized and transient increases in dynamic pressure, typically due to a combined increase in plasma velocity and density. For two approximately hour-long intervals in November, 2015 we found six jets, which are of two distinct types. (a) Two of the jets are associated with the magnetic field discontinuities at the boundary between the quasi-parallel and quasi-perpendicular magnetosheath. Straddling the boundary, the leading part of these jets contains an ion population similar to the quasi-parallel magnetosheath, while the trailing part contains ion populations similar to the quasi-perpendicular magnetosheath. Both populations are, however, cooler than the surrounding ion populations. These two jets also have clear increases in plasma density and magnetic field strength, correlated with a velocity increase. (b) Three of the jets are found embedded within the quasi-parallel magnetosheath. They contain ion populations similar to the surrounding quasi-parallel magnetosheath, but with a lower temperature. Out of these three jets, two have a simple structure. For these two jets, the increases in density and magnetic field strength are correlated with the dynamic pressure increases. The other jet has a more complicated structure, and no clear correlations between density, magnetic field strength and dynamic pressure. This jet has likely interacted with the magnetosphere, and contains ions similar to the jets inside the quasi-parallel magnetosheath, but shows signs of adiabatic heating. All jets are associated with emissions of whistler, lower hybrid, and broadband electrostatic waves, as well as approximately 10 s period electromagnetic waves with a compressional component. The latter have a Poynting flux of up to 40μWm-2 and may be energetically important for the evolution of the jets, depending on the wave excitation mechanism. Only one of the jets is likely to have modified the surrounding magnetic field into a stretched configuration, as has recently been reported in other studies. None of the jets are associated with clear signatures of either magnetic or thermal pressure gradient forces acting on them. The different properties of the two types also point to different generation mechanisms, which are discussed here. Their different properties and origins suggest that the two types of jets need to be separated in future statistical and simulation studies. [ABSTRACT FROM AUTHOR]

Ultra-low-frequency (ULF) waves in the ∼20-40 mHz range are frequently observed in the Mercury magnetosphere using Mercury Surface Space Environment Geochemistry, and Ranging (MESSENGER) magnetic field data. The majority of these waves have very similar characteristics to the waves likely driven by Kelvin-Helmholtz (KH) ULF waves (which are retained as a subset of the wave events studied in this paper) identified in a previous study. Significant ULF wave activity is observed in the dawn sector of the magnetosphere. This indicates that Mercury KH waves may be more common between 6 and 12 magnetic local time than previously predicted and that magnetospheric ULF waves in the frequency band ∼ 20-40 mHz can be used as a detection tool for Hermean KH waves. [ABSTRACT FROM AUTHOR]

We have investigated MESSENGER magnetic field data from the Mercury magnetosheath and near solar wind, to identify isolated magnetic field structures (defined as clear, isolated changes in the field magnitude). Their properties are studied in order to determine if they may be considered as analogues to plasmoids and jets known to exist in Earth's magnetosheath. Both isolated decreases of the magnetic field absolute value (‘negative magnetic field structures’) and increases (‘positive structures’) are found in the magnetosheath, whereas only negative structures are found in the solar wind. The similar properties of the solar wind and magnetosheath negative magnetic field structures suggests that they are analogous to diamagnetic plasmoids found in Earth's magnetosheath and near solar wind. The latter have earlier been identified with solar wind magnetic holes. Positive magnetic field structures are only found in the magnetosheath, concentrated to a region relatively close to the magnetopause. Their proximity to the magnetopause, their scale sizes, and the association of a majority of the structures with bipolar magnetic field signatures identify them as flux transfer events (which generally are associated with a decrease of plasma density in the magnetosheath). The positive magnetic field structures are therefore not likely to be analogous to terrestrial paramagnetic plasmoids but possibly to a sub-population of magnetosheath jets. At Earth, a majority of magnetosheath jets are associated with the quasi-parallel bow shock. We discuss some consequences of the findings of the present investigation pertaining to the different nature of the quasi-parallel bow shock at Mercury and Earth. [ABSTRACT FROM AUTHOR]

In Europe, willow (Salix spp.) trees have been used commercially since the 1980s at a large scale to produce renewable energy. While reducing fossil fuel needs, growing short rotation coppices (SRCs), such as poplar or willow, may have a high impact on local air quality as these species are known to produce high amounts of isoprene, which can lead to the production of tropospheric ozone (O3). Here, we present a long-term leaf-scale study of biogenic volatile organic compound (BVOC) emissions from a Swedish managed willow site with the aim of providing information on the seasonal variability in BVOC emissions during two growing seasons, 2015–2016. Total BVOC emissions during these two seasons were dominated by isoprene (>96% by mass) and the monoterpene (MT) ocimene. The average standardized (STD, temperature of 30 °C and photosynthetically active radiation of 1000 µmol m−2 s−1) emission rate for isoprene was 45.2 (±42.9, standard deviation (SD)) μg gdw−1 h−1. Isoprene varied through the season, mainly depending on the prevailing temperature and light, where the measured emissions peaked in July 2015 and August 2016. The average STD emission for MTs was 0.301 (±0.201) μg gdw−1 h−1 and the MT emissions decreased from spring to autumn. The average STD emission for sesquiterpenes (SQTs) was 0.103 (±0.249) μg gdw−1 h−1, where caryophyllene was the most abundant SQT. The measured emissions of SQTs peaked in August both in 2015 and 2016. Non-terpenoid compounds were grouped as other VOCs (0.751 ± 0.159 μg gdw−1 h−1), containing alkanes, aldehydes, ketones, and other compounds. Emissions from all the BVOC groups decreased towards the end of the growing season. The more sun-adapted leaves in the upper part of the plantation canopy emitted higher rates of isoprene, MTs, and SQTs compared with more shade-adapted leaves in the lower canopy. On the other hand, emissions of other VOCs were lower from the upper part of the canopy compared with the lower part. Light response curves showed that ocimene and α-farnesene increased with light but only for the sun-adapted leaves, since the shade-adapted leaves did not emit ocimene and α-farnesene. An infestation with Melampsora spp. likely induced high emissions of, e.g., hexanal and nonanal in August 2015. The results from this study imply that upscaling BVOC emissions with model approaches should account for seasonality and also include the canopy position of leaves as a parameter to allow for better estimates for the regional and global budgets of ecosystem emissions. [ABSTRACT FROM AUTHOR]

Evaluates the extent of muscle sympathetic activity (MSA) coherence between sympathetic muscles of different human limbs. Separation of cardiac- and noncardiac-related components of MSA; Regional differences between MSA in upper and lower extremities; Methodological considerations regarding the analysis technique.

Evaluates the extent to which coherence between resting muscle sympathetic activity (MSA) in different pairs of limbs in humans is explained by the common baroreceptor input and by other noncardiac-related factors. Indication that nonuniform relationship exists between resting sympathetic outflow to muscles in close and distant extremities.

The nociceptive withdrawal reflex (NWR) is used to probe spinal cord excitability in chronic pain states. Here, we used an automated and unbiased procedure for determining the NWR threshold and compared the reflex thresholds and corresponding pain ratings in a well-characterized cohort of fibromyalgia (n = 29) and matched healthy controls (n = 21). Surface electrical stimuli were delivered to the foot in a stepwise incremental and decremental manner. The surface electromyographic activity was recorded from the ipsilateral tibialis anterior muscle. Fibromyalgia patients reported significantly higher scores for psychological distress and pain-related disability and a significantly lower score for perceived state of health compared to the matched controls. The subjective pain ratings were significantly higher in patients. The NWR thresholds were similar to the controls. In the patients, but not in controls, the NWR thresholds and subjective pain ratings were significantly correlated. Our results showed an increased subjective pain sensitivity in fibromyalgia, but we found no evidence for spinal sensitization based on the reflex measures. [ABSTRACT FROM AUTHOR]

Willow (Salix spp.) trees are commonly used in short rotation coppices (SRC) to produce renewable energy. However, these plants are also known to emit high concentrations of biogenic volatile organic compounds (BVOCs), which have a large influence on air quality. Many different clones of commercially used Salix varieties exist today, but only a few studies have focused on BVOC emissions from these newer varieties. In this study, four varieties commercially propagated for biofuel production have been studied on a leaf-scale in the southern part of Sweden. The trees had either their first or second growing season, and measurements on BVOC emissions were done during the growing season in 2017 from the end of May to the beginning of September. Isoprene was the dominant emitted compound for all varieties but the average emission amongst varieties varied from 4.00 to 12.66 µg gdw−1 h−1. Average monoterpene (MT) (0.78–1.87 µg gdw−1 h−1) and sesquiterpene (SQT) emission rates (0.22–0.57 µg gdw−1 h−1) differed as well among the varieties. Besides isoprene, other compounds like ocimene, linalool and caryophyllene also showed a response to light but not for all varieties. Younger plants had several times higher emissions of non-isoprenoids (other VOCs) than the corresponding 1-year-old trees. The conclusions from this study show that the choice of variety can have a large impact on the regional BVOC emission budget. Genetics, together with stand age, should be taken into account when modelling BVOC emissions on a regional scale, for example, for air quality assessments. [ABSTRACT FROM AUTHOR]

Magnetosheath jets are high dynamic pressure structures extending from the bow shock towards the magnetopause, where they can cause different effects. They have been suggested to originate either by shock rippling or by interactions of short large-amplitude magnetic structures (SLAMS) interaction with the bow shock. Recent modelling efforts, limited to a single set of upstream conditions, have provided the first size and shape distributions of the jets that are in quantitative agreement with previous spacecraft observations. This newly established methodology makes it possible to identify several jets from different simulation runs. Here we use the Vlasiator global hybrid-Vlasov simulation to identify several jets from different runs having a variety of upstream conditions. We also identify jets from MMS spacecraft data, and gather a database of more than a thousand simulated individual jets with an identity and a lifetime and more than a thousand observed jets. We investigate the jet dimensions and physical parameters as a function of driving conditions, location and as a function of a lifetime of the jet, and compare the simulation results with observations where applicable. We find that the jets in the simulation are in good agreement with the observations, confirming earlier findings from Vlasiator. As a separate note, we also find that many jets are closely associated with SLAMS penetrating the bow shock. [ABSTRACT FROM AUTHOR]

Magnetosheath jets are flows that manifest as localized, large amplitude and transient increases of dynamic pressure. They are a vital component in the coupled system consisting of Earth's magnetosphere and the solar wind. Jets can contribute to various phenomena when they interact with the magnetopause. Surface waves, radiation belt and ionospheric flow enhancements, magnetic field fluctuations, and even auroral features are a few of the phenomena linked to magnetosheath jets.In this work, we investigate a subset of magnetosheath jets that occur in clearly identified quasi-parallel and quasi-perpendicular bow shock configuration. Magnetosheath jets can occur in either quasi-parallel or quasi-perpendicular magnetosheath or at the boundary between these regions. We here attempt to separate, analyze and quantify the differences of these jet subsets.We show the first statistical results on the separation of magnetosheath jets in four distinct subsets through analyzing the in-situ observations of the Magnetospheric Multiscale Mission (MMS) from 2015 to 2018. We will investigate the properties of the different jets to search for similarities and difference between each group. A better quantification of these properties will ideally provide a clearer picture regarding the formation mechanism of each jet subset and how this is connected to their properties. Finally, this analysis aims to contribute in answering several open questions regarding magnetosheath jets, such as their exact origin mechanism. We discuss how suggested generation mechanisms such as bow shock ripples" and "solar wind discontinuities" may or may not be consistent with the different types of jets. [ABSTRACT FROM AUTHOR]

Solar wind magnetic holes are distinct, isolated depressions of the interplanetary magnetic field. We present observations of such holes by the Rosetta spacecraft deep within the coma of comet 67P/Churyumov-Gerasimenko, between April and May 2015. During these months, the increasing cometary activity facilitated the appearance of the solar wind cavity around the cometary nucleus: Solar wind protons were increasingly excluded from the inner coma and replaced by heavy cometary ions. Even under these conditions, magnetic holes can penetrate the coma. However, they appear processed with respect to their solar wind counterparts, resembling rather magnetic holes downstream of the Earth's bow shock: They may feature bipolar instead of unipolar magnetic field signatures, as well as shifted instead of anti-correlated density enhancements with respect to the magnetic field depressions. Furthermore, magnetic holes are compressed and change their shape due to magnetic field pile-up at the comet. Their scale sizes are large when compared to the solar wind cavity, but comparable to the gyro radii of cometary heavy ions. Hence, they are of kinetic relevance, yet global structures with respect to the cometary environment. This is totally different to magnetic holes at Earth, where they are entirely magnetohydrodynamic, yet local structures with respect to magnetospheric scale sizes. [ABSTRACT FROM AUTHOR]

Cluster data from ten years' worth of aurora oval crossings are used to quantify the temporal variations of magnetic field signatures of field-aligned currents (FAC), and associated electric fields. The method is based on the cross-correlation between pairs of spacecraft as a function of the temporal separation of the auroral crossings by the respective spacecraft. When the method is applied to the large-scale variations of magnetic fields associated with whole auroral passes, it gives results consistent with those of earlier studies using smaller data sets. The electric field is shown to have lower correlations, indicating that the electric field is less temporally stable. We then apply the method to study the temporal stability of the fields as a function of latitude, local time, and the scale size of the field variations. The use of a variation of this method to discriminate between temporal and spatial variations is discussed. [ABSTRACT FROM AUTHOR]

Transient enhancements in the dynamic pressure, so-called magnetosheath jets or simply jets, are abundantly found in the magnetosheath. They travel from the bow shock through the magnetosheath towards the magnetopause. On their way through the magnetosheath, jets disturb the ambient plasma. Multiple studies already investigated their scale size perpendicular to their propagation direction, and almost exclusively in a statistical manner. In this paper, we use multi-point measurements from the Time History of Events and Macroscale Interactions during Substorms (THEMIS) mission to study the passage of a single jet. The method described here allows us to estimate the spatial distribution of the dynamic pressure within the jet. Furthermore, the size perpendicular to the propagation direction can be estimated for different cross sections. In the jet event investigated here, both the dynamic pressure and the perpendicular size increase along the propagation axis from the front part towards the center of the jet and decrease again towards the rear part, but neither monotonically nor symmetrically. We obtain a maximum diameter in the perpendicular direction of about 1 RE and a dynamic pressure of about 6 nPa at the jet center. [ABSTRACT FROM AUTHOR]

Shocklets and short large‐amplitude magnetic structures (SLAMS) are steepened magnetic fluctuations commonly found in Earth's upstream foreshock. Here we present Venus Express observations from the 26th of February 2009 establishing their existence in the steady‐state foreshock of Venus, building on a past study which found SLAMS during a substantial disturbance of the induced magnetosphere. The Venusian structures were comparable to those reported near Earth. The 2 Shocklets had magnetic compression ratios of 1.23 and 1.34 with linear polarization in the spacecraft frame. The 3 SLAMS had ratios between 3.22 and 4.03, two of which with elliptical polarization in the spacecraft frame. Statistical analysis suggests SLAMS coincide with unusually high solar wind Alfvén mach‐number at Venus (12.5, this event). Thus, while we establish Shocklets and SLAMS can form in the stable Venusian foreshock, they may be rarer than at Earth. We estimate a lower limit of their occurrence rate of ≳14%. Plain Language Summary: We discover that Venus, like Earth, also has magnetic structures called Shocklets and short large‐amplitude magnetic structures (SLAMS) in its foreshock region, which is the area upstream of the planet where the interplanetary magnetic field is connected to its bow shock. Shocklets and SLAMS are common in the foreshock of Earth. However, Shocklets have not been observed at Venus before, and SLAMS have only been seen once, and then only during a large disturbance of the space near Venus. Thus it is unknown if SLAMS and Shocklets can form in the foreshock of a planet as close to its star as Venus. We used observations from the European Space Agency's Venus Express orbiter (2006–2014) to identify these structures in the Venusian foreshock. The structures were found to be present during periods of high solar wind activity, and a lower limit on how often they occur is at least 14% of the time. These findings provide new insights into the space environment around Venus and may help us understand the differences in the space environments of different planets. Key Points: Shocklets and short large‐amplitude magnetic structures (SLAMS) can form in the steady‐state foreshock of Venus despite the magnetosphere being 1/10th the size of EarthsThe Venusian Shocklets and SLAMS had comparable magnetic signatures to those reported near Earth, but may be rarerAnalysis of the solar wind at 0.72AU suggests Shocklets and SLAMS occur during high Alfvén mach‐numbers with a lower limit on occurrence rate of ≳14% [ABSTRACT FROM AUTHOR]

Sudden, unexpected stimuli can induce a transient inhibition of sympathetic vasoconstriction to skeletal muscle, indicating a link to defense reactions. This phenomenon is relatively stable within, but differs between, individuals. It correlates with blood pressure reactivity which is associated with cardiovascular risk. Inhibition of muscle sympathetic nerve activity (MSNA) is currently characterized through invasive microneurography in peripheral nerves. We recently reported that brain neural oscillatory power in the beta spectrum (beta rebound) recorded with magnetoencephalography (MEG) correlated closely with stimulus-induced MSNA inhibition. Aiming for a clinically more available surrogate variable reflecting MSNA inhibition, we investigated whether a similar approach with electroencephalography (EEG) can accurately gauge stimulus-induced beta rebound. We found that beta rebound shows similar tendencies to correlate with MSNA inhibition, but these EEG data lack the robustness of previous MEG results, although a correlation in the low beta band (13–20 Hz) to MSNA inhibition was found (p = 0.021). The predictive power is summarized in a receiver-operating-characteristics curve. The optimum threshold yielded sensitivity and false-positive rate of 0.74 and 0.33 respectively. A plausible confounder is myogenic noise. A more complicated experimental and/or analysis approach is required for differentiating MSNA-inhibitors from non-inhibitors based on EEG, as compared to MEG. [ABSTRACT FROM AUTHOR]

Norway spruce ( Picea abies ) is one of the dominant tree species in the European boreal zone with the capacity to grow over large areas within Europe. It is an important emitter of biogenic volatile organic compounds (BVOCs), which can act as precursors of photochemical smog and ozone and contribute to the formation and growth of secondary organic aerosols (SOA) in the atmosphere. Isoprenoid emissions were measured from Norway spruce trees at seven different sites, distributed from Ljubljana in Slovenia to Piikkiö in Finland. Four of the sites were part of a network of genetically identical spruce trees and contained two separate provenances. The remaining three sites were part of other networks which have been used to conduct studies in the European boreal zone. There were minimal differences in the standardized emission rates between sites and across latitudes. The emission profile differed between provenances and sites, but there were not any distinct patterns which could be connected to a change in latitude. By using genetically identical trees and comparing the emission rates between sites and with genetically different trees, it was observed that the emission patterns were mostly influenced by genetics. But in order to confirm this possible stability of the relative emission profile based on genetics, more studies need to be performed. The effects of branch height, season and variation between years on observed emission pattern variations were also investigated. There were indications of potential influences of all three factors. However, due to different experimental setups between measurement campaigns, it is difficult to draw any robust conclusions. [ABSTRACT FROM AUTHOR]

Background: Sepsis is associated with substantial mortality rates. Antibiotic treatment is crucial, but global antibiotic resistance is now classified as one of the top ten global public health risks facing humanity. Ozone (O3) is an inorganic molecule with no evident function in the body. We investigated the bactericide properties of ozone, using a novel system of extracorporeal ozone blood treatment. We hypothesized that ozone would decrease the concentration of viable Escherichia coli (E. coli) in human whole blood and that the system would be technically feasible and physiologically tolerable in a clinically relevant model of E. coli sepsis in swine. Methods: The E. coli strain B09-11822, a clinical isolate from a patient with septic shock was used. The in vitro study treated E. coli infected human whole blood (n = 6) with ozone. The in vivo 3.5-h sepsis model randomized swine to E. coli infusion and ozone treatment (n = 5) or E. coli infusion and no ozone treatment (n = 5). Live E. coli, 5 × 107 colony-forming units (CFU/mL) was infused in a peripheral vein. Ozone treatment was initiated with a duration of 30 min after 1.5 h. Results: The single pass in vitro treatment decreased E. coli by 27%, mean 1941 to 1422 CFU/mL, mean of differences − 519.0 (95% CI − 955.0 to − 82.98, P = 0.0281). pO2 increased (95% CI 31.35 to 48.80, P = 0.0007), pCO2 decreased (95% CI − 3.203 to − 1.134, P = 0.0069), oxyhemoglobin increased (95% CI 1.010 to 3.669, P = 0.0113). Methemoglobin was not affected. In the sepsis model, 9/10 swine survived. One swine randomized to ozone treatment died from septic shock before initiation of the treatment. Circulatory, respiratory, and metabolic parameters were not affected by the ozone treatment. E. coli in arterial blood, in organs and in aerobic and anaerobic blood cultures did not differ. Hemoglobin, leucocytes, and methemoglobin were not affected by the treatment. Conclusions: Ozone decreased the concentration of viable E. coli in human whole blood. The system was technically feasible and physiologically tolerable in porcine sepsis/septic shock and should be considered for further studies towards clinical applications. [ABSTRACT FROM AUTHOR]

An individual's blood pressure (BP) reactivity to stress is linked to increased risk of hypertension and cardiovascular disease. However, inter- and intra-individual BP variability makes understanding the coupling between stress, BP reactivity, and long-term outcomes challenging. Previous microneurographic studies of sympathetic signaling to muscle vasculature (i.e. muscle sympathetic nerve activity, MSNA) have established a neural predictor for an individual's BP reactivity during short-lasting stress. Unfortunately, this method is invasive, technically demanding, and time-consuming and thus not optimal for widespread use. Potential central nervous system correlates have not been investigated. We used MagnetoEncephaloGraphy and Magnetic Resonance Imaging to search for neural correlates to sympathetic response profiles within the central autonomic network and sensorimotor (Rolandic) regions in 20 healthy young males. The main correlates include (a) Rolandic beta rebound and an anterior cingulate cortex (ACC) response elicited by sudden stimulation and (b) cortical thickness in the ACC. Our findings highlight the involvement of the ACC in reactions to stress entailing peripheral sympathetic responses to environmental stimuli. The Rolandic response furthermore indicates a surprisingly strong link between somatosensory and autonomic processes. Our results thus demonstrate the potential in using non-invasive neuroimaging-based measures of stress-related MSNA reactions, previously assessed only using invasive microneurography. [ABSTRACT FROM AUTHOR]

Magnetosheath jets are currently an important topic in the field of magnetosheath physics. It is thought that 97% of the jets are produced by the shock rippling at quasi‐parallel shocks. Recently, large statistical studies of magnetosheath jets have been performed, however, it is not clear whether rippling also produces jets found downstream of quasi‐perpendicular shocks. We analyze four types of events in the quasi‐perpendicular magnetosheath with signatures characteristic of magnetosheath jets, namely increased density and/or dynamic pressure that were not produced by the shock rippling: (a) magnetic flux tubes connected to the quasi‐parallel bow‐shock, (b) nonreconnecting current sheets, (c) reconnection exhausts, and (d) mirror‐mode waves. The flux tubes are downstream equivalents of the upstream traveling foreshocks. Magnetosheath jets can impact the magnetopause, so knowing the conditions under which they form may enable us to understand their signatures in the magnetosphere. Plain Language Summary: Magnetosheath jets have been identified as strong local enhancements of dynamic pressure or similar quantity in the magnetosheath associated to velocity and/or density enhancements. It is currently thought that ∼97% of magnetosheath jets form due to rippling of the quasi‐parallel bow‐shock. However shock rippling at the quasi‐perpendicular shock occurs on much smaller spatial scales (∼5 di, upstream ion inertial scales) than at the quasi‐parallel shock (several tens of di). It is thus not clear whether the rippling produces magnetosheath jets at the quasi‐perpendicular shock. Here, we show for the first time four different phenomena, not associated to shock rippling, that can produce magnetosheath jets in the quasi‐perpendicular magnetosheath. Three of them are already known types of events: current sheets, reconnection exhausts, and mirror‐mode waves. The fourth phenomena are magnetic flux tubes that are embedded in the quasi‐perpendicular magnetosheath but are connected to the quasi‐parallel bow‐shock. Key Points: Jets in the quasi‐perpendicular (Qper) magnetosheath may be of different origin than those in the quasi‐parallel magnetosheathSome causes of jets in the Qper magnetosheath are known phenomena, such as mirror‐mode waves, current sheets, and reconnection exhaustsSome jets in the Qper magnetosheath are due to passing magnetic flux tubes, which are downstream equivalents of traveling foreshocks [ABSTRACT FROM AUTHOR]

Magnetosheath jets are currently an important topic in the field of magnetosheath physics. It is thought that 97% of the jets are produced by the shock rippling at quasi‐parallel shocks. Recently, large statistical studies of magnetosheath jets have been performed, however, it is not clear whether rippling also produces jets found downstream of quasi‐perpendicular shocks. We analyze four types of events in the quasi‐perpendicular magnetosheath with signatures characteristic of magnetosheath jets, namely increased density and/or dynamic pressure that were not produced by the shock rippling: (a) magnetic flux tubes connected to the quasi‐parallel bow‐shock, (b) nonreconnecting current sheets, (c) reconnection exhausts, and (d) mirror‐mode waves. The flux tubes are downstream equivalents of the upstream traveling foreshocks. Magnetosheath jets can impact the magnetopause, so knowing the conditions under which they form may enable us to understand their signatures in the magnetosphere. Plain Language Summary: Magnetosheath jets have been identified as strong local enhancements of dynamic pressure or similar quantity in the magnetosheath associated to velocity and/or density enhancements. It is currently thought that ∼97% of magnetosheath jets form due to rippling of the quasi‐parallel bow‐shock. However shock rippling at the quasi‐perpendicular shock occurs on much smaller spatial scales (∼5 di, upstream ion inertial scales) than at the quasi‐parallel shock (several tens of di). It is thus not clear whether the rippling produces magnetosheath jets at the quasi‐perpendicular shock. Here, we show for the first time four different phenomena, not associated to shock rippling, that can produce magnetosheath jets in the quasi‐perpendicular magnetosheath. Three of them are already known types of events: current sheets, reconnection exhausts, and mirror‐mode waves. The fourth phenomena are magnetic flux tubes that are embedded in the quasi‐perpendicular magnetosheath but are connected to the quasi‐parallel bow‐shock. Key Points: Jets in the quasi‐perpendicular (Qper) magnetosheath may be of different origin than those in the quasi‐parallel magnetosheathSome causes of jets in the Qper magnetosheath are known phenomena, such as mirror‐mode waves, current sheets, and reconnection exhaustsSome jets in the Qper magnetosheath are due to passing magnetic flux tubes, which are downstream equivalents of traveling foreshocks [ABSTRACT FROM AUTHOR]

Magnetosheath jets are regions of high dynamic pressure, which can traverse from the bow shock towards the magnetopause. Recent modelling efforts, limited to a single jet and a single set of upstream conditions, have provided the first estimations about how the jet parameters behave as a function of position within the magnetosheath. Here we expand the earlier results by doing the first statistical investigation of the jet dimensions and parameters as a function of their lifetime within the magnetosheath. To verify the simulation behaviour, we first identify jets from Magnetosphere Multiscale (MMS) spacecraft data (6142 in total) and confirm the Vlasiator jet general behaviour using statistics of 924 simulated individual jets. We find that the jets in the simulation are in quantitative agreement with the observations, confirming earlier findings related to jets using Vlasiator. The jet density, dynamic pressure, and magnetic field intensity show a sharp jump at the bow shock, which decreases towards the magnetopause. The jets appear compressive and cooler than the magnetosheath at the bow shock, while during their propagation towards the magnetopause they thermalise. Further, the shape of the jets flatten as they progress through the magnetosheath. They are able to maintain their flow velocity and direction within the magnetosheath flow, and they end up preferentially to the side of the magnetosheath behind the quasi-parallel shock. Finally, we find that Vlasiator jets during low solar wind Alfvén Mach number MA are shorter in duration, smaller in their extent, and weaker in terms of dynamic pressure and magnetic field intensity as compared to the jets during high MA. [ABSTRACT FROM AUTHOR]

The Magnetospheric Multiscale mission (MMS1) data for 8 months in the winter periods of 2017–2018 and 2018–2019, when MMS had its apogee in the upstream solar wind of the Earth's bow shock, are used to study linear magnetic holes (LMHs). These LMHs are characterized by a magnetic depression of more than 50 % and a rotation of the background magnetic field of less then 10∘. A total of 406 LMHs are found and, based on their magnetoplasma characteristics, are split into three categories: cold (increase in density, little change in ion temperature), hot (increase in ion temperature, decrease in density) and sign change (at least one magnetic field component changes sign). The occurrence rate of LMHs is 2.3 per day. All LMHs are basically in pressure balance with the ambient plasma. Most of the linear magnetic holes are found in ambient plasmas that are stable against the mirror-mode generation, but only half of the holes are mirror-mode-stable inside. [ABSTRACT FROM AUTHOR]

The foreshock is a region of space upstream of the Earth's bow shock extending along the interplanetary magnetic field (IMF). It is permeated by shock-reflected ions and electrons, low-frequency waves, and various plasma transients. We investigate the extent of the He2+ foreshock using Vlasiator, a global hybrid-Vlasov simulation. We perform the first numerical global survey of the helium foreshock and interpret some historical foreshock observations in a global context. The foreshock edge is populated by both proton and helium field-aligned beams, with the proton foreshock extending slightly further into the solar wind than the helium foreshock and both extending well beyond the ultra-low frequency (ULF) wave foreshock. We compare our simulation results with Magnetosphere Multiscale (MMS) Hot Plasma Composition Analyzer (HPCA) measurements, showing how the gradient of suprathermal ion densities at the foreshock crossing can vary between events. Our analysis suggests that the IMF cone angle and the associated shock obliquity gradient can play a role in explaining this differing behaviour. We also investigate wave–ion interactions with wavelet analysis and show that the dynamics and heating of He2+ must result from proton-driven ULF waves. Enhancements in ion agyrotropy are found in relation to, for example, the ion foreshock boundary, the ULF foreshock boundary, and specular reflection of ions at the bow shock. We show that specular reflection can describe many of the foreshock ion velocity distribution function (VDF) enhancements. Wave–wave interactions deep in the foreshock cause de-coherence of wavefronts, allowing He2+ to be scattered less than protons. [ABSTRACT FROM AUTHOR]

We used a stepwise process to develop a new paradigm for preoperative cortical mapping of receptive language in children, using temporary functional blocking with transcranial magnetic stimulation (TMS). The method combines short sentences with a lexical decision task in which children are asked to point at a picture that fits a short sentence delivered aurally. This was first tested with 24 healthy children aged 4–16 years. Next, 75 sentences and 25 slides were presented to five healthy children in a clinical setting without TMS. Responses were registered on a separate computer, and facial expressions and hand movements were filmed for later offline review. Technical adjustments were made to combine these elements with the existing TMS equipment. The audio-recorded sentences were presented before the visual stimuli. Sentence lists were constructed to avoid similar stimuli in a row. Two different baseline lists were used before the TMS registration; the second baseline resulted in faster responses and was chosen as the reference for possible response delays induced by TMS. Protocols for offline reviews were constructed. No response, incorrect response, self-correction, delayed response, and perseveration were considered clear stimulation effects, while poor attention, discomfort, and other events were regarded as unclear. Finally, three children (6:2, 14:0, 14:10 years) with epilepsy and expected to undergo neurosurgery were assessed using TMS (left hemisphere in one; both hemispheres in the other two). In the two assessed bilaterally, TMS effects indicated bilateral language processing. Delayed response was the most common error. This is a first attempt to develop a new TMS paradigm for receptive language mapping, and further evaluation is suggested. • A first attempt to develop a new TMS paradigm for receptive language mapping • The method was tried out in healthy children and in children with epilepsy. • This procedure was developed for children from 6 years of age. [ABSTRACT FROM AUTHOR]

We used a stepwise process to develop a new paradigm for preoperative cortical mapping of receptive language in children, using temporary functional blocking with transcranial magnetic stimulation (TMS). The method combines short sentences with a lexical decision task in which children are asked to point at a picture that fits a short sentence delivered aurally. This was first tested with 24 healthy children aged 4–16 years. Next, 75 sentences and 25 slides were presented to five healthy children in a clinical setting without TMS. Responses were registered on a separate computer, and facial expressions and hand movements were filmed for later offline review. Technical adjustments were made to combine these elements with the existing TMS equipment. The audio-recorded sentences were presented before the visual stimuli. Sentence lists were constructed to avoid similar stimuli in a row. Two different baseline lists were used before the TMS registration; the second baseline resulted in faster responses and was chosen as the reference for possible response delays induced by TMS. Protocols for offline reviews were constructed. No response, incorrect response, self-correction, delayed response, and perseveration were considered clear stimulation effects, while poor attention, discomfort, and other events were regarded as unclear. Finally, three children (6:2, 14:0, 14:10 years) with epilepsy and expected to undergo neurosurgery were assessed using TMS (left hemisphere in one; both hemispheres in the other two). In the two assessed bilaterally, TMS effects indicated bilateral language processing. Delayed response was the most common error. This is a first attempt to develop a new TMS paradigm for receptive language mapping, and further evaluation is suggested. • A first attempt to develop a new TMS paradigm for receptive language mapping • The method was tried out in healthy children and in children with epilepsy. • This procedure was developed for children from 6 years of age. [ABSTRACT FROM AUTHOR]

The Plasma Wave Investigation (PWI) aboard the BepiColombo Mio (Mercury Magnetospheric Orbiter, MMO) will enable the first observations of electric fields, plasma waves, and radio waves in and around the Hermean magnetosphere and exosphere. The PWI has two sets of receivers (EWO with AM2P, SORBET) connected to two electric field sensors (MEFISTO and WPT) and two magnetic field sensors (SCM: LF-SC and DB-SC). After the launch on October 20, 2018, we began initial operations, confirmed that all receivers were functioning properly, and released the launch locks on the sensors. Those sensors are not deployed during the cruising phase, but the PWI is still capable performing magnetic field observations. After full deployment of all sensors following insertion into Mercury orbit, the PWI will start its measurements of the electric field from DC to 10 MHz using two dipole antennae with a 32-m tip-to-tip length in the spin plane and the magnetic field from 0.3 Hz to 20 kHz using a three-axis sensor and from 2.5 kHz to 640 kHz using a single-axis sensor at the tip of a 4.5-m solid boom extended from the spacecraft's side panel. Those receivers and sensors will provide (1) in-situ measurements of electron density and temperature that can be used to determine the structure and dynamics of the Hermean plasma environment; (2) in-situ measurements of the electron and ion scale waves that characterize the energetic processes governed by wave–particle interactions and non-MHD interactions; (3) information on radio waves, which can be used to remotely probe solar activity in the heliocentric sector facing Mercury, to study electromagnetic-energy transport to and from Mercury, and to obtain crustal information from reflected electromagnetic waves; and (4) information concerning dust impacts on the spacecraft body detected via potential disturbances. This paper summarizes the characteristics of the overall PWI, including its significance, its objectives, its expected performance specifications, and onboard and ground data processing. This paper also presents the detailed design of the receiver components installed in a unified chassis. The PWI in the cruise phase will observe magnetic-field turbulence during multiple flybys of Earth, Venus, and Mercury. After the Mercury-orbit insertion planned at the end of 2025, we will deploy all sensors and commence full operation while coordinating with all payloads onboard the Mio and MPO spacecraft. [ABSTRACT FROM AUTHOR]

The occurrence rate of linear and pseudo magnetic holes has been determined during MESSENGER's cruise phase starting from Venus (2007) and arriving at Mercury (2011). It is shown that the occurrence rate of linear magnetic holes, defined as a maximum of 10 ∘ rotation of the magnetic field over the hole, slowly decreases from Mercury to Venus. The pseudo magnetic holes, defined as a rotation between 10 and 45 ∘ over the hole, have mostly a constant occurrence rate. [ABSTRACT FROM AUTHOR]

This flux transfer event (FTE) study is based on 989 FTEs, originally identified by Wang et al. (2005) in Cluster data. Due to Cluster's orbit the FTE list exclusively contains events detected at the high-latitude dayside magnetopause and low-latitude flanks. The focus of the present study is on FTE separation time. Our results show significant differences between FTE cascades and isolated FTE events regarding IMF conditions and distribution along the magnetopause. Most FTE cascades are observed during strongly negative IMF By. They appear mainly in the northern dusk and southern dawn region of the magnetopause, which in agreement with the expected rapid azimuthal motion of FTEs that form during dominant IMF By. In contrast, isolated FTEs appear typically during IMF conditions with average IMF By close to zero. As could be expected for near zero IMF By conditions, isolated FTEs are nearly uniformly spread over the entire magnetopause region that is covered by Cluster crossings. A subset of isolated FTEs appears during IMF conditions with low cone angles suggesting that these may form as a result of magnetosheath jets impacting on the magnetopause. A detailed examination of Cluster magnetic field and particle data reveals further differences between isolated and FTE cascades that may explain why certain FTEs to appear only as isolated events. This is discussed in detail in the present work. [ABSTRACT FROM AUTHOR]

We use a global hybrid-Vlasov simulation for the magnetosphere, Vlasiator, to investigate magnetosheath high-speed jets. Unlike many other hybrid-kinetic simulations, Vlasiator includes an unscaled geomagnetic dipole, indicating that the simulation spatial and temporal dimensions can be given in SI units without scaling. Thus, for the first time, this allows investigating the magnetosheath jet properties and comparing them directly with the observed jets within the Earth's magnetosheath. In the run shown in this paper, the interplanetary magnetic field (IMF) cone angle is 30°, and a foreshock develops upstream of the quasi-parallel magnetosheath. We visually detect a structure with high dynamic pressure propagating from the bow shock through the magnetosheath. The structure is confirmed as a jet using three different criteria, which have been adopted in previous observational studies. We compare these criteria against the simulation results. We find that the magnetosheath jet is an elongated structure extending earthward from the bow shock by ~ 2:6RE, while its size perpendicular to the direction of propagation is ~ 0:5RE. We also investigate the jet evolution and find that the jet originates due to the interaction of the bow shock with a high-dynamic-pressure structure that reproduces observational features associated with a short, large-amplitude magnetic structure (SLAMS). The simulation shows that magnetosheath jets can develop also under steady IMF, as inferred by observational studies. To our knowledge, this paper therefore shows the first global kinetic simulation of a magnetosheath jet, which is in accordance with three observational jet criteria and is caused by a SLAMS advecting towards the bow shock. [ABSTRACT FROM AUTHOR]

Recent studies strongly suggest that a majority of the observed O+ cusp outflows will eventually escape into the solar wind, rather than be transported to the plasma sheet. Therefore, an investigation of plasma sheet flows will add to these studies and give a more complete picture of magnetospheric ion dynamics. Specifically, it will provide a greater understanding of atmospheric loss. We have used Cluster spacecraft 4 to quantify the H+ and O+ total transports in the near-Earth plasma sheet, using data covering 2001-2005. The results show that both H+ and O+ have earthward net fluxes of the orders of 1026 and 1024 s-1, respectively. The OC plasma sheet return flux is 1 order of magnitude smaller than the O+ outflows observed in the cusps, strengthening the view that most ionospheric O+ outflows do escape. The H+ return flux is approximately the same as the ionospheric outflow, suggesting a stable budget of H+ in the magnetosphere. However, low-energy H+, not detectable by the ion spectrometer, is not considered in our study, leaving the complete magnetospheric H+ circulation an open question. Studying tailward flows separately reveals a total tailward O+ flux of about 0:5×1025 s-1, which can be considered as a lower limit of the nightside auroral region O+ outflow. Lower velocity flows (< 100 km s-1) contribute most to the total transports, whereas the high-velocity flows contribute very little, suggesting that bursty bulk flows are not dominant in plasma sheet mass transport. [ABSTRACT FROM AUTHOR]

The article focuses on a study on whether baseline muscle sympathetic nerve activity (MSNA) is related to the differences in sympathetic baroreflex responsiveness to rising and falling diastolic blood pressure (DBP) in young and older men and women. It notes the use of peroneal microneurography and the spontaneous baroreflex threshold technique to measure MSNA and baroreflex sensitivity (BRS), respectively. According to the findings, sympathetic BRS is dependent upon the level of sympathetic activity at rest.

The sensitivity of baroreflex control of sympathetic nerve activity (SNA) represents the responsiveness of SNA to changes in blood pressure. In a slightly different analysis, the baroreflex threshold measures the probability of whether a sympathetic burst will occur at a given diastolic blood pressure. We hypothesized that baroreflex threshold analysis could be used to estimate the sensitivity of the sympathetic baroreflex measured by the pharmacological modified Oxford test. We compared four measures of sympathetic baroreflex sensitivity in 25 young healthy participants: the "gold standard" modified Oxford analysis (nitroprusside and phenylephrine), nonbinned spontaneous baroreflex analysis, binned spontaneous baroreflex analysis, and threshold analysis. The latter three were performed during a quiet baseline period before pharmacological intervention. The modified Oxford baroreflex sensitivity was significantly related to the threshold slope (r = 0.71, P < 0.05) but not to the binned (1 mmHg bins) and the nonbinned spontaneous baroreflex sensitivity (r = 0.22 and 0.36, respectively, P > 0.05), which included burst area. The threshold analysis was also performed during the modified Oxford manipulation. Interestingly, we found that the threshold analysis results were not altered by the vasoactive drugs infused for the modified Oxford. We conclude that the noninvasive threshold analysis technique can be used as an indicator of muscle SNA baroreflex sensitivity as assessed by the modified Oxford technique. Furthermore, the modified Oxford method does not appear to alter the properties of the baroreflex. [ABSTRACT FROM AUTHOR]

Autonomic nervous system activity changes have been described during cataplexy as playing a role in triggering it. To confirm these previous findings, we investigated the time course of sympathetic and cardiovascular activities during cataplexy. We made for the first time microneurographic recordings of 10 cataplectic episodes in three patients with hypocretin-deficient narcolepsy. During microneurography, muscle sympathetic nerve activity (MSNA) was recorded simultaneously with heart rate (HR), respiratory movements, arterial finger blood pressure (BP), electroencephalography, electro-oculogram and superficial electromyogram. Results showed no significant autonomic changes before the onset of the cataplectic episodes. Cataplexy was associated with a significant increase in MSNA and BP compared with baseline, whereas HR was markedly decreased. An irregular breathing pattern mainly characterized by apnea typically occurred during the attacks. In conclusion, our findings did not show significant changes in autonomic activity prior to cataplexy onset, ruling out a triggering role of the autonomic system. However, cataplexy was associated with co-activation of sympathetic and parasympathetic autonomic systems, a pattern reminiscent of that reported during the vigilance reaction in animals. [ABSTRACT FROM AUTHOR]

Abstract: The anti-migraine drug sumatriptan often induces unpleasant somatosensory side effects, including a dislike of being touched. With a double-blind cross-over design, we studied the effects of sumatriptan and saline on perception (visual analogue scale) and cortical processing (functional magnetic resonance imaging) of tactile stimulation in healthy subjects. Soft brush stroking on the calf (n =6) was less pleasant (p <0.04) and evoked less activation of posterior insular cortex in the sumatriptan compared to the saline condition. Soft brushing activated pain processing regions (anterior insular, lateral orbitofrontal, and anterior cingulate cortices, and medial thalamus) only in the sumatriptan condition, whereas activation of somatosensory cortices was similar in both conditions. Soft brush stroking on the palm (n =6) was equally pleasant in both conditions. One possible mechanism for the activation of pain processing regions by brush stroking is sensitization of nociceptors by sumatriptan. Another possibility is inhibition of a recently discovered system of low-threshold unmyelinated tactile (CT) afferents that are present in hairy skin only, project to posterior insular cortex, and serve affective aspects of tactile sensation. An inhibition of impulse transmission in the CT system by sumatriptan could disinhibit nociceptive signalling and make light touch less pleasant. This latter alternative is consistent with the observed reduction in posterior insular cortex activation and the selective effects of stimulation on hairy compared to glabrous skin, which are not explained by the nociceptor sensitization account. [Copyright &y& Elsevier]

The aim of this study was to investigate the relationships among sympathetic hyperactivity, excessive daytime sleepiness (EDS) and hypertension in obstructive sleep apnoea syndrome (OSAS). Ten newly diagnosed OSAS patients with untreated EDS and daytime hypertension underwent polysomnography (PSG) and daytime measurements of plasma noradrenaline (NA), ambulatory blood pressure (BP), muscle sympathetic nerve activity (MSNA) by microneurography and objective assessment of EDS before and during 6 months of compliance-monitored continuous positive airway pressure (CPAP) treatment. One month after the start of CPAP, BP, MSNA and NA were significantly lowered, remaining lower than baseline also after 3 and 6 months of treatment. CPAP use caused a significant improvement of sleep structures, and reduced EDS. A statistical correlation analysis demonstrated that EDS was not correlated with sleep measures obtained from baseline PSG (% sleep stages, apnoea and arousal index, mean oxygen saturation value), whereas daytime sleepiness was significantly correlated with MSNA. Furthermore, MSNA and BP showed no correlation. Our data obtained from selected patients suggest that the mechanisms inducing EDS in OSAS are related to the degree of daytime sympathetic hyperactivity. Additionally, resting MSNA was unrelated to BP suggesting that factors other than adrenergic neural tone make a major contribution to OSAS-related hypertension. The results obtained in this pilot study need, however, to be confirmed in a larger study involving more patients. [ABSTRACT FROM AUTHOR]

A large portion of atmospheric aerosol particles consists of secondary material produced by oxidation reactions. The relative importance of secondary organic aerosol (SOA) can increase with improved emission regulations. A relatively simple way to study potential particle formation in the atmosphere is by using oxidation flow reactors (OFRs) which simulate atmospheric ageing. Here we report on the first ambient OFR ageing experiment in Europe, coupled with scanning mobility particle sizer (SMPS), aerosol mass spectrometer (AMS) and proton transfer reaction (PTR)-MS measurements. We found that the simulated ageing did not produce any measurable increases in particle mass or number concentrations during the two months of the campaign due to low concentrations of precursors. Losses in the reactor increased with hydroxyl radical (OH) exposure and with increasing difference between ambient and reactor temperatures, indicating fragmentation and evaporation of semivolatile material. [ABSTRACT FROM AUTHOR]

Plasmoids, defined as plasma entities with a higher anti-sunward velocity component than the surrounding plasma, have been observed in the magnetosheath in recent years. Among other denominations, plasmoids are also called "magnetosheath jets" and can be classified by transient localized enhancements in dynamic pressure. Using measurements by the Magnetospheric Multiscale (MMS) spacecraft and criteria proposed by Gunell et al. (2014), Karlsson et al. (2012), Archer and Horbury (2013) and Plaschke et al. (2013), were identified several thousand events in distance up to 3 Earth radii from the bow shock. Based on our statistical analysis and previous studies, we discuss features of the "plasmoids" and "jets", their properties, occurrence, relation to solar wind and foreshock conditions, and their sources. [ABSTRACT FROM AUTHOR]

We report the detection of large-amplitude, quasi-harmonic density-fluctuations withassociated magnetic field oscillations in the region surrounding the diamagnetic cavity ofcomet 67P. Typical frequencies are ∼0.1 Hz, corresponding to ∼10 times the water and ≲0.5times the proton gyro-frequencies, respectively. Magnetic field oscillations are not alwaysclearly observed in association to these density fluctuations, but when they are, theyconsistently have wave vectors perpendicular to the background magnetic field, with theprincipal axis of polarization close to field-aligned and with a ∼90∘ phase lag w.r.t. thedensity fluctuations. The fluctuations are observed in association with asymmetric plasma andmagnetic field enhancements previously found in the region surrounding the diamagneticcavity, occurring predominantly on their descending slopes. We speculate that they are IonBernstein waves (IBWs) excited by the drift-cyclotron instability resulting fromstrong plasma inhomogeneities in the region surrounding the diamagnetic cavity. [ABSTRACT FROM AUTHOR]

The magnetosheath flow may take the form of large amplitude, yet spatially localized, transient increases in dynamic pressure, known as “magnetosheath jets” or “plasmoids” among other denominations. Here, we describe the present state of knowledge with respect to such jets, which are a very common phenomenon downstream of the quasi-parallel bow shock. We discuss their properties as determined by satellite observations (based on both case and statistical studies), their occurrence, their relation to solar wind and foreshock conditions, and their interaction with and impact on the magnetosphere. As carriers of plasma and corresponding momentum, energy, and magnetic flux, jets bear some similarities to bursty bulk flows, which they are compared to. Based on our knowledge of jets in the near Earth environment, we discuss the expectations for jets occurring in other planetary and astrophysical environments. We conclude with an outlook, in which a number of open questions are posed and future challenges in jet research are discussed. [ABSTRACT FROM AUTHOR]