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Laser-Induced Breakdown Spectroscopy, as utilized by the ChemCam instrument onboard the Curiosity rover, detected enhanced abundances of the element copper. Since landing in Gale crater (August 6, 2012) 10 enhancements in copper abundance were observed during 3007 Martian days (sols) of rover operations and 24 km of driving (as of January 20, 2021). The most prominent ones were found in the Kimberley area on the crater floor (Aeolis Palus) and in Glen Torridon on the lower flanks of Aeolis Mons (Mt. Sharp). Enhancements in copper record the former existence of modestly acidic and oxidizing fluids, which were more oxidizing in Kimberley than in Glen Torridon. Of the two main types of bedrock in the lowest part of Glen Torridon, Mg-rich ‘coherent’ and K-rich ‘rubbly’ (named based on their outcrop expression), copper was only detected in coherent, not in rubbly bedrock. The difference between these two types of bedrock may be due to difference in provenance. Alternatively, based on a recently developed lacustrine-groundwater mixing model, we suggest that rubbly bedrock was altered by modestly acidic, shallow-subsurface lake water that leached out both copper and manganese, while coherent bedrock was affected by dominantly alkaline fluids which would be consistent with its mineralogical composition (including siderite) as returned by the CheMin instrument onboard the rover. Higher up in Glen Torridon, ChemCam data indicated significant gradients in copper concentration in coherent bedrock on a local scale of only few meters, which suggests a different alteration style and possibly different types of diagenetic fluids.

International audience; Several factors can contribute to the difficulty of aligning the sensors of tracking detectors, including a large number of modules, multiple types of detector technologies, and non-linear strip patterns on the sensors. The latter two of these three factors apply to the CLAS12 CVT, which is a hybrid detector consisting of planar silicon sensors with non-parallel strips, and cylindrical micromegas sensors with longitudinal and arc-shaped strips located within a 5 T superconducting solenoid. To align this detector, we used the Kalman Alignment Algorithm, which accounts for correlations between the alignment parameters without requiring the time-consuming inversion of large matrices. This is the first time that this algorithm has been adapted for use with hybrid technologies, non-parallel strips, and curved sensors. We present the results for the first alignment of the CLAS12 CVT using straight tracks from cosmic rays and from a target with the magnetic field turned off. After running this procedure, we achieved alignment at the level of l. 967 10μm, and the widths of the residual spectra were greatly reduced. These results attest to the flexibility of this algorithm and its applicability to future use in the CLAS12 CVT and other hybrid or curved trackers, such as those proposed for the future Electron-Ion Collider.

During the first 2934 sols of the Curiosity rover’s mission 33,468 passive visible/near-infrared reflectance spectra were taken of the surface by the mast-mounted ChemCam instrument on a range of target types. ChemCam spectra of bedrock targets from the Murray and Carolyn Shoemaker formations on Mt. Sharp were investigated using principal component analysis (PCA) and various spectral parameters including the band depth at 535 nm and the slope between 840 nm and 750 nm. Four endmember spectra were identified. Passive spectra were compared to Laser Induced Breakdown Spectroscopy (LIBS) data to search for correlations between spectral properties and elemental abundances. The correlation coefficient between FeOT reported by LIBS and BD535 from passive spectra was used to search for regions where iron may have been added to the bedrock through oxidation of ferrous-bearing fluids, but no correlations were found. Rocks in the Blunts Point-Sutton Island transition that have unique spectral properties compared to surrounding rocks, that is flat near-infrared (NIR) slopes and weak 535 nm absorptions, are associated with higher Mn and Mg in the LIBS spectra of bedrock. Additionally, calcium-sulfate cements, previously identified by Ca and S enrichments in the LIBS spectra of bedrock, were also shown to be associated with spectral trends seen in Blunts Point. A shift towards steeper near-infrared slope is seen in the Hutton interval, indicative of changing depositional conditions or increased diagenesis.

The Curiosity rover of the Mars Science Laboratory has been exploring since mid-2021 the lower sulfate unit of Mount Sharp in the Gale crater. This unit, first described from orbital observations as showing spectral signatures of hydrated sulfate minerals [1], has recently been revealed to record a major paleoenvironmental and climatic transition during the Hesperian-Noachian transition, with the onset of alternating wet and dry conditions before a complete aridification of Martian conditions [2]. Before the current campaign, this unit was mainly studied using remote observations (e.g., [2, 3]), but Curiosity has now entered this major interval allowing to precisely study the rock record leading to this major climatic event.Since the rover left the Glen Torridon area (aka the clay-bearing unit, Fig. 1), the Curiosity rover entered the sulfate-bearing unit (~Sol 3100, mid-2021; Fig. 1) and traversed sedimentary series mainly composed of fine to coarse sandstones. While no clear facies change or sharp contact has been observed when entering the sulfate-bearing unit, these levels differ from the previously observed terrains in Gale by an increased occurrence of nodular features with a strong sulfate geochemical signature [4, 5], polygonal ridges [4], or even halite detections [6]. Otherwise, the sedimentary structures and grain-size are continuous across the upper members of the Carolyn Shoemaker formation and into the overlying Mirador formation, indicating a likely continuity in the continental settings for most of these deposits.Such structures are notably well visible at the Prow locality, a major outcrop situated in the Contigo member of the Mirador formation, just below the Greenheugh pediment (Fig. 1). This outcrop has been reached and studied in January and February 2022, between sols 3349 and 3379. Using ~3200 mid- and close-range images from the Navigation and Mast cameras (Navcam, Mastcam), we used structure-from-motion photogrammetry to reconstruct a Digital Outcrop Model (following the method described in [7]) of the Prow locality and its vicinity (Fig. 2). This DOM covers an area of about 1000m². Two small excerpts of this DOM are explorable online on the Sketchfab platform at https://skfb.ly/o8DJZ and https://skfb.ly/otpLW. The DOM allows us to visualize and characterize several sets of meter- to centimeter-scale sedimentary structures, over about 30 meters of lateral continuity, either using on-screen visualization, or integrated within a Virtual Reality environment.The DOM reconstruction has been helpful in determining the targets of interest during the Prow exploration by Curiosity. One particular benefit has been to identify the Toron block (Fig. 2) as a fallen piece of the main outcrop, allowing us to perform very close-range observations of the outcrop’s cliff-face (e.g., Fig. 3a) without actually putting the rover too close to the actual rock-face. The interest of using such 3D reconstruction notably lies in the ability to characterize the spatial distribution of the multi-scale structures observed at the Prow, but also to study the spatial distribution (and potential variations) of the geochemical composition of these layered sandstones as seen by the ChemCam instrument. We also take advantage of the high-resolution micro-images provided by the Remote Micro-Imager subsystem of the ChemCam instrument (with a field of view of 20 mrad per frame, resolving grains under the silt at close range) to study the facies (grain-size, micro-structures) of the different sandstone beds cropping out at this locality (Fig. 3).At the Prow, we characterize several sets of sedimentary structures such as (but not limited to) meter-scale cross-stratifications, cm-scale symmetric ripples but also probable climbing ripples (Fig. 3a). These structures, mostly indicating a direction of transport toward the NW (similar to what is observed in underlying Glen Torridon area), denotates sustained aqueous conditions compatible with a fluvial setting. We also observe in some place at the Prow, and notably in the upper layers, mm-scale fine-grained draping (Fig. 3b) deposited at the surface of (cross-)stratifications, reminiscent of flaser bedding on Earth. These fine muddy levels indicate recurrent intervals of low-energy deposition in-between higher-energy periods. Put together, these elements help us to characterize sustained aqueous conditions in a dynamic setting of combined flow and wave action at the time the sediments were deposited (e.g., [8]), helping us to determine probable mixed fluvio-aeolian settings around the critical climatic transition observed within this sulfate-bearing unit characterized by alternating wet and dry conditions.References: [1] Miliken et al., 2010, Geophys. Res. Lett. 37, L04201; [2] Rapin et al., 2021, Geology 49; [3] Caravaca et al., 2021, Remote Sensing, 13(20), 4068; [4] Rapin et al., 2022, EPSC, this meeting; [5] Schieber et al., 2022, LPSC, Abstract #1304; [6] Meslin et al., 2022, LPSC, Abstract #2492; [7] Caravaca et al., 2020, Planet. Space Science 182, 104808 ; [8] Gupta et al., 2022, ESPC, this meeting.

The goal of the uRANIA-V (μ-RWELL Advanced Neutron Imaging Apparatus) project is the development of an innovative thermal neutron detector based on micro-Resistive WELL (μ-RWELL) technology and surface Resistive Plate Counter (sRPC) technology. A thin layer of 10B4C on the cathode surface allows the thermal neutron conversion into 7Li and α ions to be easily detected in the active volume of the device. These charged particles ionize the gas in the detectors and the readout measures the signal. Test results with different converter layouts show that a thermal neutron (25meV) detection efficiency between 5 ÷ 10 % can be achieved with a single detector. A detailed comparison between the experimental data and the full simulation of the neutron physics and the detector behavior has been performed. Future applications of these technologies range from neutron diffraction imaging to radioactive waste monitor or radiation portal monitoring for homeland security. In this proceeding, the results of the neutron conversion optimization of the Boron thickness and the converted geometry will be discussed together with the development of new electronics integrated with μ-RWELL and sRPC. Experimental results and simulation measurements will be compared.

Bacteriocins are peptides of ribosomal synthesis that are active against bacteria related to the producing strain. They have been widely used in the food industry as biopreservatives. The generation of hybrid peptides by combining the genes that encode two different bacteriocins has made it possible to study the mechanisms of action of the bacteriocins that compose them and also develop new peptides with improved biotechnological applications. Hybrid bacteriocins may be obtained in several ways. In our laboratory, by combining enterocin CRL35 and microcin V (Ent35-MccV), we obtained a broad-spectrum peptide that is active against both Gram-positive and Gram-negative bacteria. Ent35-MccV is sensitive to the action of intestinal proteases and is heat resistant, which makes it a good candidate for use as a biopreservative. For this reason, the peptide was tested in skim milk and beef burgers as food models. We also obtained more potent variants of the hybrid by modifying the central amino acid of the hinge region that connects the two bacteriocins. This review also discusses future applications and perspectives regarding the Ent35-MccV and other hybrid peptides.Key Points• Ent35-MccV is a new broad-spectrum bacteriocin.• The mechanism of action of bacteriocins can be studied using hybrid peptides.• Genetic engineering allows obtaining improved bacteriocin derivatives.• Hybrid peptides can be used in the food, pharmaceutical, and veterinary applications.

We present the first measurement of di-hadron angular correlations in electron-nucleus scattering. The data were taken with the CLAS detector and a 5.0 GeV electron beam incident on deuterium, carbon, iron, and lead targets. Relative to deuterium, the nuclear yields of charged-pion pairs show a strong suppression for azimuthally opposite pairs, no suppression for azimuthally nearby pairs, and an enhancement of pairs with large invariant mass. These effects grow with increased nuclear size. The data are qualitatively described by the GiBUU model, which suggests that hadrons form near the nuclear surface and undergo multiple-scattering in nuclei. These results show that angular correlation studies can open a new way to elucidate how hadrons form and interact inside nuclei, Comment: 6 pages, 4 figures

International audience; Glen Torridon is a topographic trough located on the slope of Aeolis Mons, Gale crater, Mars. It corresponds to what was previously referred to as the “clay-bearing unit”, due to the relatively strong spectral signatures of clay minerals (mainly ferric smectites) detected from orbit. Starting in January 2019, the Curiosity rover explored Glen Torridon for more than 700 sols (Martian days). The objectives of this campaign included acquiring a detailed understanding of the geologic context in which the clay minerals were formed, and determining the intensity of aqueous alteration experienced by the sediments. Here, we present the major-element geochemistry of the bedrock as analyzed by the ChemCam instrument. Our results reveal that the two main types of bedrock exposures identified in the lower part of Glen Torridon are associated with distinct chemical compositions (K-rich and Mg-rich), for which we are able to propose mineralogical interpretations. Moreover, the topmost stratigraphic member exposed in the region displays a stronger diagenetic overprint, especially at two locations close to the unconformable contact with the overlying Stimson formation, where the bedrock composition significantly deviates from the rest of Glen Torridon. Overall, the values of the Chemical Index of Alteration determined with ChemCam are elevated by Martian standards, suggesting the formation of clay minerals through open-system weathering. However, there is no indication that the alteration was stronger than in some terrains previously visited by Curiosity, which in turn implies that the enhanced orbital signatures are mostly controlled by non-compositional factors.

International audience; The clay-rich Glen Torridon region of Gale crater, Mars, was explored between sols 2300 and 3007. Here, we analyzed the diagenetic features observed by Curiosity, including veins, cements, nodules, and nodular bedrock, using the ChemCam, Mastcam, and Mars Hand Lens Imager instruments. We discovered many diagenetic features in Glen Torridon, including dark-toned iron- and manganese-rich veins, magnesium- and fluorine-rich linear features, Ca-sulfate cemented bedrock, manganese-rich nodules, and iron-rich strata. We have characterized the chemistry and morphology of these features, which are most widespread in the higher stratigraphic members in Glen Torridon, and exhibit a wide range of chemistries. These discoveries are strong evidence for multiple generations of fluids from multiple chemical endmembers that likely underwent redox reactions to form some of these features. In a few cases, we may be able to use mineralogy and chemistry to constrain formation conditions of the diagenetic features. For example, the dark-toned veins likely formed in warmer, highly alkaline, and highly reducing conditions, while manganese-rich nodules likely formed in oxidizing and circumneutral conditions. We also hypothesize that an initial enrichment of soluble elements, including fluorine, occurred during hydrothermal alteration early in Gale crater history to account for elemental enrichment in nodules and veins. The presence of redox-active elements, including Fe and Mn, and elements required for life, including P and S, in these fluids is strong evidence for habitability of Gale crater groundwater. Hydrothermal alteration also has interesting implications for prebiotic chemistry during the earliest stages of the crater’s evolution and early Mars.

Before the Perseverance rover landing, the acoustic environment of Mars was unknown. Models predicted that: (1) atmospheric turbulence changes at centimetre scales or smaller at the point where molecular viscosity converts kinetic energy into heat

Introduction In January 2019, the Mars Science Laboratory (MSL) rover Curiosity started exploring the Glen Torridon (GT) region of Gale crater, which corresponds to the topographic trough between the Vera Rubin ridge and the Greenheugh pediment (Fig. 1). From orbit, this region stands out due to the rela­tively strong near-infrared signatures of clay minerals [1,2]. The in-situ data collected so far by Curiosity have allowed the MSL team to confirm and quantify the presence of these clay minerals [3], to characterize their organic content [4], and to document in detail their geochemical and sedimentological settings [5]. In particular, the bedrock chemistry measured by ChemCam shows elevated values of the Chemical Index of Alteration (CIA) throughout most of Glen Torridon [6,7], which indicates an open-system type of alteration [8]. In addition, the ChemCam observations suggest the presence of illite in the fine-grained rocks [9] and reveal a possible relationship between grain size and geochemical variations [10]. Finally, they show that the light-toned rocks located just below the uncon­formity at the base of the Greenheugh pediment (Fig. 1) are associated with “anoma­lous” bedrock compositions that may be related to a late-stage diagenetic event at Gale [7]. Here, we report the findings of the ChemCam instrument along a ~2-km eastward traverse within the upper member – named Glasgow – of the Glen Torridon region (Fig. 1). This traverse allowed Curiosity to investigate the lateral variability of this member, while also getting gradually closer to the transition into the overlying sulfate-bearing unit [11]. Dataset ChemCam measures the chemical composition of targeted rocks and soils within a few meters of the rover using laser-induced breakdown spectro­scopy (LIBS). Quantification of eight major rock-forming oxides is performed routinely [12]. Each Chem­Cam analysis consists of a raster of several points a few millimeters apart from each other, and each point itself consists of a series of laser shots (typically 30). For bedrock targets, this approach allows removal of unwanted contributions from Ca-sulfate veins or soil material by discarding the corresponding points [e.g., 8]. On sol 3007, ChemCam experienced a technical issue, which required halting the use of the laser during the time of the investigation, while imaging and passive spectroscopy activities continued. LIBS analyses on Mars targets resumed on sol 3107, in the Mont Mercou area (Fig. 1), ~600 m to the east and ~19 m higher in elevation. In addition, data acquired between sols 2816 and 2956 are not used here, since they correspond to a downsection excursion into the underlying Knockfarril Hill member [13]. Results Variations in MgO, K2O and FeOT abun­dances along the rover path within the Glasgow member are shown in Figures 2, 3 and 4 (respectively). The bedrock composition is overall homogeneous, although small variations are observed for some oxides. In particular, the mean MgO abundance was well below 5 wt% in the western part of the traverse, but reached nearly 6 wt% after the downsection excursion (Fig. 2). This increase in MgO is accompanied by slightly lower Al2O3 abundances (not shown here). In contrast, the K2O content does not show a clear change after the excursion (Fig. 3); however, it decreases slightly during the exploration of an area with rougher terrain (previously mapped as “fIU rubbly” [14]), between sols 2973 and 3000. Regarding FeOT, large variations have been observed at small scale (i.e., within a given LIBS raster) in a group of targets characterized by the presence of dark nodules, likely of diagenetic origin [15,16]. These nodules have high FeOT (up to ~50 wt%), whereas the points in between the nodules show low FeOT (down to ~12.5 wt%). However, at the scale of the whole Glasgow member, the mean FeOT content is quite stable, with only a subtle increase in the eastern part of the traverse (Fig. 4). As mentioned above, the most recent data (last bin in Fig. 2-4) were acquired after a gap of ~600 m laterally and ~19 m vertically. Despite this gap, the bedrock compositions appear remarkably similar to those measured earlier in the Glasgow member, especially after the downsection excursion. This suggests that no major change of environment occurred during the time when LIBS was unavailable. Discussion and conclusion Curiosity’s eastward traverse within the Glasgow member is a rare opportunity to investigate the lateral variability of Gale sedimentary strata at the kilometer scale. The compositions appear overall homogeneous, but some variations are observed. As previously seen in Glen Torridon [6,7,10], Mg and K are the two most varying elements; however, their variations are not always well correlated, as illustrated by the trends observed after the downsection excursion (Fig. 2-3). In addition, while FeOT displays significant variations within some LIBS rasters due to the presence of dark nodules in the bedrock, it is stable at the scale of the whole Glasgow member, which suggests that diagenetic remobilization of iron occurred at small scale only. Finally, the latest data acquired in the Mont Mercou area show that the bedrock compositions are still remarkably similar to those measured ~2 km to the west, when Curiosity first encountered the Glasgow member. As the rover continues to progress uphill, ChemCam will continue surveying the bedrock in search of the first chemical indications of the clay-to-sulfate transition. References: [1] Milliken et al. (2010) GRL, 37. [2] Fraeman et al. (2016) JGR-Planets, 121. [3] Thorpe et al. (2021) LPSC, abstract #1519. [4] Millan et al. (2021) LPSC, abstract #2039. [5] Fedo et al. (2020) LPSC, abstract #2345. [6] Dehouck et al. (2020) LPSC, abstract #2770. [7] Dehouck et al. (2020) AGU Fall Meeting, abstract #P070-06. [8] Mangold et al. (2019) Icarus, 321. [9] Cousin et al. (2021) LPSC, abstract #2127. [10] Caravaca et al. (2021) LPSC, abstract #1455. [11] Rapin et al. (2021) Geology, 49. [12] Clegg et al. (2017) Spectrochim. Acta B, 129. [13] Dehouck et al. (2021) LPSC, abstract #1858. [14] Hughes et al. (2021) LPSC, abstract #1586. [15] David et al. (2021) LPSC, abstract #1433. [16] Gasda et al. (2021) LPSC, abstract #1271.

We discuss two complementary strategies to search for light dark matter (LDM) exploiting the positron beam possibly available in the future at Jefferson Laboratory. LDM is a new compelling hypothesis that identifies dark matter with new sub-GeV "hidden sector" states, neutral under standard model interactions and interacting with our world through a new force. Accelerator-based searches at the intensity frontier are uniquely suited to explore it. Thanks to the high intensity and the high energy of the CEBAF (Continuous Electron Beam Accelerator Facility) beam, and relying on a novel LDM production mechanism via positron annihilation on target atomic electrons, the proposed strategies will allow us to explore new regions in the LDM parameters space, thoroughly probing the LDM hypothesis as well as more general hidden sector scenarios., 11 pages, 8 figures. Prepared for submission in EPJA. This work supersedes the corresponding contribution in arXiv:2007.15081. Added aknowledgement to Jefferson Lab

Gale crater on Mars records a large section of sedimentary rocks, mainly represented by the 5-km-thick sequence of Mount Sharp (Aeolis Mons). The lower part of this sequence has been explored by the Curiosity rover of the Mars Science Laboratory (MSL) mission, revealing lacustrine to fluvial depositional sequences [e.g., 1] bearing clay minerals [2]. Orbital observations highlighted the presence of clay minerals at the base of Mt Sharp but also hint at a major wet to dry environmental change with clay-bearing rocks giving way to several hundred of meters of sulfate-bearing strata [3, 4]. Orbital data coupled with rover-based observations revealed that the sulfate-bearing unit record coincides with a major change of depositional environment followed by alternation of wetter and drier conditions rather than a monotonous aridification during the Hesperian epoch [5]. Before Curiosity reached this part of Gale crater, those observations were supported using long-distance imaging capabilities of the Remote Micro-Imager (RMI) sub-system of the ChemCam instrument [6]. With a focal length of 700 mm, the RMI telescope complements the color Mastcam imagers with higher spatial resolution views of sedimentary structures and textures of rocks outcropping several hundred meters up to a few kilometers away from the rover (a ~60 km-record observation having recently been achieved, [7]). This capacity is therefore used by the MSL team both to plan future guidance of the rover and to observe geologic features from a distance. These long-distance observations pointed at the sulfate-bearing unit reveal the presence of sub-metric-scale cross-stratifications and deflation surfaces as well as diagenetic features (e.g., “satin spar”; Fig. 1). While their size allows for long-range remote observation (i.e., several hundred meters away using imagers onboard the rover, Mastcam and RMI), the resulting images lacks depth due to the distance. Yet, such 3D information can be critical in characterizing and understanding the sedimentary processes behind the setting of these structures. To improve our observations, we are conducting an imaging experiment to reconstruct the 3D shape of the sulfate-bearing unit outcrops with Structure-from-Motion photogrammetry using ChemCam’s RMI frames. This method is usually performed on close-range geologic features observed with other imagers onboard the rover (MAHLI, Mastcam, Navcam, [8]), but such an approach had never been applied to long-distance RMI frames. Here, we apply photogrammetric treatment to specific sets of repeated long-distance observations on the sulfate-bearing unit. To cope with the high distance of the target, we use a several-hundred meters “virtual baseline” represented by successive positions of the rover along its traverse. Figure 1 shows one of the two long-distance (1x12) RMI mosaics (ccam04947, taken on Sol 2947, cf. Fig. 2) which served as input in the stereoscopic test. This mosaic illustrates an outcrop of the sulfate-bearing unit situated ~650 meters away from the rover at that time (Fig. 2). A second similar mosaic pointed at the same target was taken on Sol 2962 (2x16 RMI mosaic, ccam04962) after the rover drove about 200 meters southeastwards (Fig. 2). By combining the individual frames of these two mosaics in the photogrammetric chain, we were able to reconstruct the shape of the outcrop. The resulting 3D model presented in Figure 3 reveals the actual 3D shape of the imaged outcrop situated several hundred meters away from the rover, as well as displaying with improved accuracy the spatial distribution of the sedimentary and/or diagenetic structures. The use of this technique to produce long-distance 3D models will have critical implication in helping to assess and to characterize the depositional conditions related to the sulfate-bearing unit, a key objective of the Curiosity rover. The use of these models could also serve to help planning the upcoming exploration of this interval by designating high-interest targets. We also look forward to applying this method to long-distance color images obtained with the more advanced color RMI subsystem of the SuperCam instrument onboard the Perseverance rover currently operating in Jezero crater [9, 10]. References:[1] Caravaca et al., 2021 LSPC, abstract #1455; [2] Thorpe M. T. et al., 2021, LPSC, Abstract #1519; [3] Miliken et al., 2010, Geophys. Res. Lett. 37, L04201; [4] Fraeman A. A. et al., 2016, J. Geophys. Res. Planets 121, 1713–1736; [5] Rapin et al., 2021, Geology 49; [6] Le Mouélic et al., 2015, Icarus 249, 93-107; [7] Le Mouélic et al., 2021, LPSC Abstract #1408; [8] Caravaca et al., 2020, Planet. Space Science 182, 104808; [9] Gasnault et al., 2021, LPSC Abstract #2248; [10] Gasnault et al., 2021, EGU Abstract #EGU21-16461.

Resumen Objetivo La medicion de la osmolaridad lagrimal en pacientes con ojo seco ha sido cuestionada debido a su alta variabilidad. El entendimiento del origen de dicha variabilidad ayudaria a la interpretacion clinica de los valores obtenidos. Esta investigacion evalua la medicion de la variabilidad lagrimal en la practica clinica. Material y metodos Veinte pacientes con ojo seco y 20 controles fueron evaluados. Fueron realizadas 3 mediciones consecutivas de osmolaridad a intervalos de 5 min. La variabilidad fue definida como la diferencia entre las mediciones mas extremas obtenidas en cada ojo. Se utilizaron tecnicas de aprendizaje de maquinas para evaluar la capacidad discriminadora de la osmolaridad lagrimal. Resultados La osmolaridad promedio en el grupo control y ojo seco fueron 295,1 ± 7,3 mOsm/L y 300,6 ± 11,2 mOsm/L, respectivamente (p = 0,004). La variabilidad de la osmolaridad lagrimal fue 7,5 ± 3,6 mOsm/L en el grupo control y 16,7 ± 11,9 mOsm/L en los pacientes con ojo seco (p Conclusiones La osmolaridad promedio y la variabilidad fueron significativamente mas altas en pacientes con ojo seco. Por otra parte, las tecnicas de aprendizaje de maquina demostraron buena precision para clasificar a los pacientes. Por tanto, la alta variabilidad parece ser caracteristica propia de la enfermedad de ojo seco.

The beam spin asymmetry of the exclusive pseudoscalar channel e → p → e ′ p ′ η was measured for the first time in the deep-inelastic regime ( W > 2 GeV / c 2 and Q 2 > 1 GeV 2 / c 2 ) using a longitudinally polarized 5.78 GeV electron beam at Jefferson Lab with the CEBAF Large Acceptance Spectrometer. The data were accumulated in 144 four-dimensional bins of Q 2 , x B , − t and ϕ over a wide kinematic range, where ϕ is the azimuthal angle between the lepton and hadron scattering planes, The measured azimuthal dependence with large amplitudes of the sin ⁡ ϕ moments is a clear indication of a substantial contribution to the polarized cross-section from transversely polarized virtual photons. In the framework of generalized parton distributions (GPDs) this contribution is expressed via longitudinal-transverse interference between chiral-even and chiral-odd GPDs. The experimental results are compared to the existing theoretical models demonstrating the sensitivity to the product of chiral-odd and chiral-even GPDs and provide new constraints to the existing GPD parameterizations.

The observation of beam spin asymmetries in two-pion production in semi-inclusive deep inelastic scattering off an unpolarized proton target is reported for the first time. The data presented here were taken in the fall of 2018 with the CLAS12 spectrometer using a 10.6 GeV longitudinally spin-polarized electron beam delivered by CEBAF at JLab. The measured asymmetries provide the first observation of a signal that can be used to extract the PDF $e(x)$ in a collinear framework and the helicity-dependent two-pion fragmentation function $G_1^\perp$.

Background The quality of care in labor and delivery is traditionally measured through the Hospital Consumer Assessment of Healthcare Providers and Systems but less is known about the experiences of care reported by patients and caregivers on online sites that are more easily accessed by the public. Objective The aim of this study was to generate insight into the labor and delivery experience using hospital reviews on Yelp. Methods We identified all Yelp reviews of US hospitals posted online from May 2005 to March 2017. We used a machine learning tool, latent Dirichlet allocation, to identify 100 topics or themes within these reviews and used Pearson r to identify statistically significant correlations between topics and high (5-star) and low (1-star) ratings. Results A total of 1569 hospitals listed in the American Hospital Association directory had at least one Yelp posting, contributing a total of 41,095 Yelp reviews. Among those hospitals, 919 (59%) had at least one Yelp rating for labor and delivery services (median of 9 reviews), contributing a total of 6523 labor and delivery reviews. Reviews concentrated among 5-star (n=2643, 41%) and 1-star reviews (n=1934, 30%). Themes strongly associated with favorable ratings included the following: top-notch care (r=0.45, P Conclusions Online review content about labor and delivery can provide meaningful information about patient satisfaction and experiences. Narratives from these reviews that are not otherwise captured in traditional surveys can direct efforts to improve the experience of obstetrical care.

BACKGROUND The quality of care in labor and delivery is traditionally measured through the Hospital Consumer Assessment of Healthcare Providers and Systems but less is known about the experiences of care reported by patients and caregivers on online sites that are more easily accessed by the public. OBJECTIVE The aim of this study was to generate insight into the labor and delivery experience using hospital reviews on Yelp. METHODS We identified all Yelp reviews of US hospitals posted online from May 2005 to March 2017. We used a machine learning tool, latent Dirichlet allocation, to identify 100 topics or themes within these reviews and used Pearson r to identify statistically significant correlations between topics and high (5-star) and low (1-star) ratings. RESULTS A total of 1569 hospitals listed in the American Hospital Association directory had at least one Yelp posting, contributing a total of 41,095 Yelp reviews. Among those hospitals, 919 (59%) had at least one Yelp rating for labor and delivery services (median of 9 reviews), contributing a total of 6523 labor and delivery reviews. Reviews concentrated among 5-star (n=2643, 41%) and 1-star reviews (n=1934, 30%). Themes strongly associated with favorable ratings included the following: top-notch care (r=0.45, Pr=0.52, Pr=0.46, Pr=0.44, Pr=0.38, Pr=0.30, Pr=0.47, Pr=0.32, P CONCLUSIONS Online review content about labor and delivery can provide meaningful information about patient satisfaction and experiences. Narratives from these reviews that are not otherwise captured in traditional surveys can direct efforts to improve the experience of obstetrical care.

The quark structure of the f2(1270) meson has, for many years, been assumed to be a pure quark-antiquark (qq¯) resonance with quantum numbers JPC=2++. Recently, it was proposed that the f2(1270) is a molecular state made from the attractive interaction of two ρ mesons. Such a state would be expected to decay strongly to final states with charged pions due to the dominant decay ρ→π+π-, whereas decay to two neutral pions would likely be suppressed. Here, we measure for the first time the reaction γp→π0π0p, using the CEBAF Large Acceptance Spectrometer detector at Jefferson Lab for incident beam energies between 3.6 and 5.4 GeV. Differential cross sections, dσ/dt, for f2(1270) photoproduction are extracted with good precision due to low backgrounds and are compared to theoretical calculations.