Smartphone-interrogated test supports for the enzymatic determination of putrescine and cadaverine in food

Diamino-oxidase (DAO), horseradish peroxidase (HRP), and tetramethylbenzidine (TMB) have been immobilized into cellulose to obtain circular cellulose test supports (CCTSs) for the determination of cadaverine (Cad) and putrescine (Put). During the enzymatic reaction, TMB is oxidized and a blue spot is obtained. This color (RGB coordinates) is measured with a smartphone and a commercial application. The highest sensitivity is provided by the component R and a linear response is observed for low biogenic amine (BA) concentrations, but a second-order polynomial response better fits the experimental results for a wider concentration range. This has been successfully explained with a model developed to explain the RGB values obtained in this type of analytical system. Optimization studies enable CCTSs to be obtained for Put and Cad determination, which could be used (kept at 4 °C) for at least 45 days if a stabilizer (StabilCoat™ or StabilGuard™) is added during its synthesis. In these conditions, the R coordinate follows the model up to at least 4 × 10-4 M Put and/or Cad (both analytes give the same response). The method permits the Put and Cad determination from 5 × 10-5 M up to 4 × 10-4 M (RSD = 3%, n = 3). The CCTSs have been applied to Put + Cad determination in a tuna sample without any interference by other biogenic amines. The concentration found statistically agrees with that obtained using a HPLC-MS-validated method

Winds at the Mars 2020 Landing Site. 2. Wind Variability and Turbulence

Wind speeds measured by the Mars 2020 Perseverance rover in Jezero crater were fitted as a Weibull distribution. InSight wind data acquired in Elysium Planitia were also used to contextualize observations. Jezero winds were found to be much calmer on average than in previous landing sites, despite the intense aeolian activity observed. However, a great influence of turbulence and wave activity was observed in the wind speed variations, thus driving the probability of reaching the highest wind speeds at Jezero, instead of sustained winds driven by local, regional, or large-scale circulation. The power spectral density of wind speed fluctuations follows a power-law, whose slope deviates depending on the time of day from that predicted considering homogeneous and isotropic turbulence. Daytime wave activity is related to convection cells and smaller eddies in the boundary layer, advected over the crater. The signature of convection cells was also found during dust storm conditions, when prevailing winds were consistent with a tidal drive. Nighttime fluctuations were also intense, suggesting strong mechanical turbulence. Convective vortices were usually involved in rapid wind fluctuations and extreme winds, with variations peaking at 9.2 times the background winds. Transient high wind events by vortex-passages, turbulence, and wave activity could be driving aeolian activity at Jezero. We report the detection of a strong dust cloud of 0.75–1.5 km in length passing over the rover. The observed aeolian activity had major implications for instrumentation, with the wind sensor suffering damage throughout the mission, probably due to flying debris advected by winds.The authors acknowledge and thank the Mars 2020 team. The authors would like to thank Editors and two anonymous reviewers for their constructive reviews, which greatly improved this manuscript. This work is supported by the Spanish Ministry of Science and Innovation, under project RTI2018-098728-B-C31. The derived data presented in this work were processed in the DPS24PA system, which is supported by project no. DV2020-ATM-A01. Part of the research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (80NM0018D0004). The UPV/EHU team is supported by Grant PID2019-109467GB-I00 funded by 1042 MCIN/AEI/10.13039/501100011033/ and by Grupos Gobierno Vasco IT1742-22

Mars 2020 Perseverance Rover Studies of the Martian Atmosphere Over Jezero From Pressure Measurements

The pressure sensors on Mars rover Perseverance measure the pressure field in the Jezero crater on regular hourly basis starting in sol 15 after landing. The present study extends up to sol 460 encompassing the range of solar longitudes from Ls ∼ 13°–241° (Martian Year (MY) 36). The data show the changing daily pressure cycle, the sol-to-sol seasonal evolution of the mean pressure field driven by the CO2 sublimation and deposition cycle at the poles, the characterization of up to six components of the atmospheric tides and their relationship to dust content in the atmosphere. They also show the presence of wave disturbances with periods 2–5 sols, exploring their baroclinic nature, short period oscillations (mainly at night-time) in the range 8–24 min that we interpret as internal gravity waves, transient pressure drops with duration ∼1–150 s produced by vortices, and rapid turbulent fluctuations. We also analyze the effects on pressure measurements produced by a regional dust storm over Jezero at Ls ∼ 155°.The UPV/EHU team (Spain) is supported by Grant PID2019-109467GB-I00 funded by 1042 MCIN/AEI/10.13039/501100011033/ and by Groups Gobierno Vasco IT1742-22. GM wants to acknowledge JPL funding from USRA Contract Number 1638782. A. Vicente-Retortillo is supported by the Spanish State Research Agency (AEI) Project No. MDM-2017-0737 Unidad de Excelencia “María de Maeztu”- Centro de Astrobiología (INTA-CSIC). Part of the research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (80NM0018D0004). GM wants to acknowledge JPL funding from USRA Contract Number 1638782

Convective Vortices and Dust Devils Detected and Characterized by Mars 2020

We characterize vortex and dust devils (DDs) at Jezero from pressure and winds obtained with the Mars Environmental Dynamics Analyzer (MEDA) instrument on Mars 2020 over 415 Martian days (sols) (Ls = 6°–213°). Vortices are abundant (4.9 per sol with pressure drops >0.5 Pa correcting from gaps in coverage) and they peak at noon. At least one in every five vortices carries dust, and 75% of all vortices with Δp > 2.0 Pa are dusty. Seasonal variability was small but DDs were abundant during a dust storm (Ls = 152°–156°). Vortices are more frequent and intense over terrains with lower thermal inertia favoring high daytime surface-to-air temperature gradients. We fit measurements of winds and pressure during DD encounters to models of vortices. We obtain vortex diameters that range from 5 to 135 m with a mean of 20 m, and from the frequency of close encounters we estimate a DD activity of 2.0–3.0 DDs km−2 sol−1. A comparison of MEDA observations with a Large Eddy Simulation of Jezero at Ls = 45° produces a similar result. Three 100-m size DDs passed within 30 m of the rover from what we estimate that the activity of DDs with diameters >100 m is 0.1 DDs km−2sol−1, implying that dust lifting is dominated by the largest vortices in Jezero. At least one vortex had a central pressure drop of 9.0 Pa and internal winds of 25 ms−1. The MEDA wind sensors were partially damaged during two DD encounters whose characteristics we elaborate in detail.The authors are very grateful to the entire Mars 2020 science operations team. The authors would also like to thank Lori Fenton and an anonymous reviewer for many suggestions that greatly improved the manuscript. This work was supported by Grant PID2019-109467GB-I00 funded by MCIN/AEI/10.13039/501100011033/ and by Grupos Gobierno Vasco IT1742-22 and by the Spanish National Research, Development and Innovation Program, through the Grants RTI2018-099825-B-C31, ESP2016-80320-C2-1-R, and ESP2014-54256-C4-3-R. Baptiste Chide is supported by the Director's Postdoctoral Fellowship from the Los Alamos National Laboratory. M. Lemmon is supported by contract 15-712 from Arizona State University and 1607215 from Caltech-JPL. R. Lorenz was supported by JPL contract 1655893. Germán Martínez acknowledges JPL funding from USRA Contract Number 1638782. A. Munguira was supported by Grant PRE2020-092562 funded by MCIN/AEI and by “ESF Investing in your future.” A. Vicente-Retortillo is supported by the Spanish State Research Agency (AEI) Project No. MDM-2017-0737 Unidad de Excelencia “María de Maeztu”-Centro de Astrobiología (INTA-CSIC), and by the Comunidad de Madrid Project S2018/NMT-4291 (TEC2SPACE-CM). Part of the research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (80NM0018D0004). Finnish researchers acknowledge the Academy of Finland Grant 328 310529. Researchers based in France acknowledge support from the CNES for their work on Perseverance

The Mars Environmental Dynamics Analyzer, MEDA. A Suite of Environmental Sensors for the Mars 2020 Mission

86 pags., 49 figs., 24 tabs.NASA’s Mars 2020 (M2020) rover mission includes a suite of sensors to monitor current environmental conditions near the surface of Mars and to constrain bulk aerosol properties from changes in atmospheric radiation at the surface. The Mars Environmental Dynamics Analyzer (MEDA) consists of a set of meteorological sensors including wind sensor, a barometer, a relative humidity sensor, a set of 5 thermocouples to measure atmospheric temperature at ∼1.5 m and ∼0.5 m above the surface, a set of thermopiles to characterize the thermal IR brightness temperatures of the surface and the lower atmosphere. MEDA adds a radiation and dust sensor to monitor the optical atmospheric properties that can be used to infer bulk aerosol physical properties such as particle size distribution, non-sphericity, and concentration. The MEDA package and its scientific purpose are described in this document as well as how it responded to the calibration tests and how it helps prepare for the human exploration of Mars. A comparison is also presented to previous environmental monitoring payloads landed on Mars on the Viking, Pathfinder, Phoenix, MSL, and InSight spacecraft.This work has been funded by the Spanish Ministry of Economy and Competitiveness, through the projects No. ESP2014-54256-C4-1-R (also -2-R, -3-R and -4-R) and AYA2015-65041-P; Ministry of Science, Innovation and Universities, projects No. ESP2016-79612-C3-1-R (also -2-R and -3-R), ESP2016-80320-C2-1-R, RTI2018-098728-B-C31 (also -C32 and -C33) and RTI2018-099825-B-C31; Instituto Nacional de Técnica Aeroespacial; Ministry of Science and Innovation’s Centre for the Development of Industrial Technology; Grupos Gobierno Vasco IT1366-19; and European Research Council Consolidator Grant no 818602. The US co-authors performed their work under sponsorship from NASA’s Mars 2020 project, from the Game Changing Development program within the Space Technology Mission Directorate and from the Human Exploration and Operations Directorate

Dust Devil Frequency of Occurrence and Radiative Effects at Jezero Crater, Mars, as Measured by MEDA Radiation and Dust Sensor (RDS)

The Mars Environmental Dynamics Analyzer, onboard the Perseverance rover, is a meteorological station that is operating on Mars and includes, among other sensors, the radiometer Radiation and Dust Sensor (RDS). From RDS irradiance observations, a total of 374 dust devils (DDs) were detected for the first 365 sols of the mission (Ls = 6°–182°), which along with wind and pressure measurements, we estimated a DD frequency of formation at Jezero between 1.3 and 3.4 DD km −2 sol −1 (increasing as we move from spring into summer). This frequency is found to be smaller than that estimated at the Spirit or Pathfinder landing sites but much greater than that derived at InSight landing site. The maximum in DD frequency occurs between 12:00 and 13:00 local true solar time, which is when the convective heat flux and lower planetary boundary layer IR heating are both predicted to peak in Jezero crater. DD diameter, minimum height, and trajectory were studied showing (a) an average diameter of 29 m (or a median of 25 m) and a maximum and minimum diameter of 132 ± 63.4 and 5.6 ± 5.5 m; (b) an average minimum DD height of 231 m and a maximum minimum-height of 872 m; and (c) the DD migration direction is in agreement with wind measurements. For all the cases, DDs decreased the UV irradiance, while at visible or near-IR wavelengths both increases and decreases were observed. Contrary to the frequency of formation, these results indicate similar DD characteristics in average for the studied period

The diverse meteorology of Jezero crater over the first 250 sols of Perseverance on Mars

ASA’s Perseverance rover’s Mars Environmental Dynamics Analyzer is collecting data at Jezero crater, characterizing the physical processes in the lowest layer of the Martian atmosphere. Here we present measurements from the instrument’s first 250 sols of operation, revealing a spatially and temporally variable meteorology at Jezero. We find that temperature measurements at four heights capture the response of the atmospheric surface layer to multiple phenomena. We observe the transition from a stable night-time thermal inversion to a daytime, highly turbulent convective regime, with large vertical thermal gradients. Measurement of multiple daily optical depths suggests aerosol concentrations are higher in the morning than in the afternoon. Measured wind patterns are driven mainly by local topography, with a small contribution from regional winds. Daily and seasonal variability of relative humidity shows a complex hydrologic cycle. These observations suggest that changes in some local surface properties, such as surface albedo and thermal inertia, play an influential role. On a larger scale, surface pressure measurements show typical signatures of gravity waves and baroclinic eddies in a part of the seasonal cycle previously characterized as low wave activity. These observations, both combined and simultaneous, unveil the diversity of processes driving change on today’s Martian surface at Jezero crater

The Mars Environmental Dynamics Analyzer, MEDA. A Suite of Environmental Sensors for the Mars 2020 Mission

86 pags, 49 figs, 24 tabsNASA's Mars 2020 (M2020) rover mission includes a suite of sensors to monitor current environmental conditions near the surface of Mars and to constrain bulk aerosol properties from changes in atmospheric radiation at the surface. The Mars Environmental Dynamics Analyzer (MEDA) consists of a set of meteorological sensors including wind sensor, a barometer, a relative humidity sensor, a set of 5 thermocouples to measure atmospheric temperature at ∼1.5 m and ∼0.5 m above the surface, a set of thermopiles to characterize the thermal IR brightness temperatures of the surface and the lower atmosphere. MEDA adds a radiation and dust sensor to monitor the optical atmospheric properties that can be used to infer bulk aerosol physical properties such as particle size distribution, non-sphericity, and concentration. The MEDA package and its scientific purpose are described in this document as well as how it responded to the calibration tests and how it helps prepare for the human exploration of Mars. A comparison is also presented to previous environmental monitoring payloads landed on Mars on the Viking, Pathfinder, Phoenix, MSL, and InSight spacecraft.This work has been funded by the Spanish Ministry of Economy and Competitiveness, through the projects No. ESP2014-54256-C4-1-R (also -2-R, -3-R and -4-R) and AYA2015-65041-P; Ministry of Science, Innovation and Universities, projects No. ESP2016-79612-C3-1-R (also -2-R and -3-R), ESP2016-80320-C2-1-R, RTI2018-098728-B-C31 (also -C32 and -C33) and RTI2018-099825-B-C31; Instituto Nacional de Tecnica Aeroespacial; Ministry of Science and Innovation's Centre for the Development of Industrial Technology; Grupos Gobierno Vasco IT1366-19; and European Research Council Consolidator Grant no 818602.Peer reviewe