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The boundary between the thermosphere and exosphere is often given the simplified description of being a separation between highly collisional continuum mechanics and a collisionless domain. The realistic smooth transition through this space has historically presented a challenge to model as the assumptions used to simplify the Boltzmann equation in fluid models are invalidated at higher altitudes. A lack of rigorous modeling of the region limits the ability to understand the dynamics of light atmospheric species. This manuscript describes the dynamics present in a two‐way coupled fluid‐particle atmospheric model extending from the mesosphere through the exosphere with a smooth transition between fluid and particle domains. This model is used to examine the coupled nature of the thermosphere and exosphere using the fluid simulation TIME‐GCM and the direct simulation Monte Carlo simulation Monaco. The coupled model allows for examination of the thermosphere circulation and exosphere transport mechanisms, as well as their impacts on the distribution of hydrogen. In this analysis, upper transport regions in the exosphere are revealed and distinguished from lower transport regions during June solstice. Furthermore, coupling allows TIME‐GCM to account for effects of lateral exospheric transport of hydrogen, altering its upper boundary condition and consequentially the spatial distribution of hydrogen throughout the thermosphere. Finally, it is asserted that a self‐consistent hydrogen exobase distribution is necessary to constrain other analytical extrapolation techniques used to predict the vertical hydrogen profile in the exosphere. Plasma interactions are excluded from this study to isolate neutral dynamics. Plain Language Summary: With increasing altitude, the density of the atmosphere decreases. High above the ground, the gas can no longer be described as a continuous fluid. Instead, the motion of individual atoms is important. This transition occurs near 350–500 km (220–310 miles) in altitude, between the thermosphere and exosphere, making this region difficult to simulate. A common solution is to use a direct simulation Monte Carlo model to describe the motion of atoms in the exosphere and a fluid model to describe gas circulation in the thermosphere. However, previous studies have imposed unrealistic conditions on such combined models and not allowed the thermosphere to react to exospheric gas motion. This study describes the results of allowing a simulation of each region to be informed by the other. A focus is placed on neutral hydrogen, which comprises an increasing fraction of the gas at high altitudes, influences Earth's reaction to solar events, and undergoes atmospheric escape. With the new model, hydrogen motion in the exosphere can be fully realized. This motion affects the upper boundary of the thermospheric model and its hydrogen distribution. Finally, simplified methods for finding hydrogen density in the exosphere are compared to examine what type of errors may result. Key Points: A two‐way coupled thermosphere‐exosphere model permits analysis of hydrogen's competing thermospheric circulation and exospheric transportCoupling alters TIME‐GCM's hydrogen density distribution through transport between exosphere and thermosphere modelsA self‐consistent exobase hydrogen density is needed to constrain extrapolation methods predicting exospheric densities above fluid models [ABSTRACT FROM AUTHOR]

In this paper, the equatorial thermosphere anomaly (ETA) is investigated using accelerometer measurements to determine whether the feature is density‐dominated, wind‐dominated, or some combination of the two. An ascending‐descending accelerometry (ADA) technique is introduced to address the density‐wind ambiguity that appears when interpreting the ETA in atmospheric drag acceleration analyses. This technique separates ascending and descending acceleration measurements to determine if a wind's directionality influences the interpretation of the observed ETA feature. The ADA technique is applied to accelerometer measurements taken from the Challenging Minisatellite Payload mission and has revealed that the ETA is primarily density‐dominated from 9:00 to 16:00 local time (LT) near 400 km altitude, with the acceleration perturbations behaving similarly between 2003 and 2004 across all seasons. This finding suggests that the perturbations in the acceleration due to in‐track wind perturbations are small compared to the perturbations due to mass density, while indicating that the formation mechanisms across these local times are similar and persistent. The results also revealed that in the terminator region at 18:00 LT the acceleration perturbations deviate appreciably between ascending and descending passes, indicating different or multiple processes occurring at this local time compared to the 9:00–16:00 LT ascribed to the ETA. These results help constrain ETA formation theories to specific local times and thermospheric property responses without the use of supplemental wind measurements, while also indicating regions where in‐track winds cannot always be neglected. Plain Language Summary: Earth's thermosphere, a layer in the upper atmosphere, is a highly variable region that contributes to satellite drag in low Earth orbit. The equatorial thermosphere anomaly (ETA) is a perturbation feature that produces increases and decreases in drag accelerations across the lower latitudes of the thermosphere. Direct measurements of the thermosphere are often limited, so satellite instruments, such as accelerometers, have been used to analyze the acceleration that a satellite experiences due to atmospheric drag to indirectly measure thermospheric properties. However, the measured drag acceleration is dependent on both mass density and wind, making it difficult to determine whether a change in drag across the ETA is due to either property. This has implications on what mechanisms are responsible for its formation. This work introduces an ascending‐descending accelerometry technique to exploit the fact that while acceleration perturbations produced by mass density are independent of satellite direction, those arising from winds can either be positive or negative depending on the relative spacecraft motion. By separating satellite orbits into ascending (south‐to‐north) and descending (north‐to‐south) passes, it can be determined whether drag acceleration perturbations are due to mass density, wind, or a mixture of the two, helping constrain possible formation mechanisms. Key Points: Accelerometer observations of the Equatorial Thermosphere Anomaly (ETA) cannot distinguish between in‐track density and wind perturbationsA new technique is applied to observations determining that the ETA, occurring between 9 and 16 LT, is a density‐dominated featureThe ETA demonstrates repeatable annual behavior for each season, suggesting a common and persistent formation mechanism [ABSTRACT FROM AUTHOR]

This study focuses on utilizing the increasing availability of satellite trajectory data from global navigation satellite system‐enabled low‐Earth orbiting satellites and their precision orbit determination (POD) solutions to expand and refine thermospheric model validation capabilities. The research introduces an updated interface for the GEODYN‐II POD software, leveraging high‐precision space geodetic POD to investigate satellite drag and assess density models. This work presents a case study to examine five models (NRLMSIS2.0, DTM2020, JB2008, TIEGCM, and CTIPe) using precise science orbit (PSO) solutions of the Ice, Cloud, and Land Elevation Satellite‐2 (ICESat‐2). The PSO is used as tracking measurements to construct orbit fits, enabling an evaluation according to each model's ability to redetermine the orbit. Relative in‐track deviations, quantified by in‐track residuals and root‐mean‐square errors (RMSe), are treated as proxies for model densities that differ from an unknown true density. The study investigates assumptions related to the treatment of the drag coefficient and leverages them to eliminate bias and effectively scale model density. Assessment results and interpretations are dictated by the timescale at which the scaling occurs. DTM2020 requires the least scaling (∼−7%) to achieve orbit fits closely matching the PSO within an in‐track RMSe of 7 m when scaled over 2 weeks and 2 m when scaled daily. The remaining models require substantial scaling of the mean density offset (∼30 − 75%) to construct orbit fits that meet the aforementioned RMSe criteria. All models exhibit slight over or under‐sensitivity to geomagnetic activity according to trends in their 24‐hr scaling factors. Plain Language Summary: This research aims to make use of data from well‐tracked satellites that orbit close to Earth where they still interact with the atmosphere via satellite drag. The goal is to use high‐quality orbit solutions of satellites to provide additional means of testing density models of the Earth's upper atmosphere. By updating a precise orbit software tool called GEODYN‐II, we demonstrate how a satellite's orbit is affected by the drag forces from different density models of the upper atmosphere, and how those orbits can be used to assess the accuracy of the models. Each density model produces an orbit fit that deviates from the precise orbit of a satellite, and these deviations are used as proxies for model error relative to the unknown true density. We tested five different models using precise orbit solutions from the ICESat‐2 satellite. Various assumptions related to the drag force are investigated and used to scale the model densities at different timescales. We find that all models benefit from scaling to produce orbit fits that more closely match the ICESat‐2 precise orbit. Key Points: Precision orbit determination solutions are expanded to study satellite drag and assess upper atmospheric density models using GEODYNA proof‐of‐concept case study assessment of density models is presented using ICESat‐2 precise science orbits and orbit fitsAssessment results are provided for empirical (MSIS2, DTM2020, JB2008) and physics‐based (TIEGCM, CTIPe) models for 14‐days in November 2018 [ABSTRACT FROM AUTHOR]

Themospheric conditions during a minor geomagnetic event of 3 and 4 February 2022 has been investigated using disk temperature (Tdisk) observations from Global‐scale Observations of the Limb and Disk (GOLD) mission and model simulations. GOLD observed that the Tdisk increases by more than 60 K during the storm event when compared with pre‐storm quiet days. A comparison of the Tdisk with effective temperatures (Teff, i.e., a weighted average based on airglow emission layer) from Mass Spectrometer Incoherent Scatter radar version 2 (MSIS2) and Multiscale Atmosphere‐Geospace Environment (MAGE) models shows that MAGE outperforms MSIS2 during this particular event. MAGE underestimates the Teff by about 2%, whereas MSIS2 underestimates it by 7%. As temperature enhancements lead to an expansion of the thermosphere and resulting density changes, the value of the temperature enhancement observed by GOLD can be utilized to find a GOLD equivalent MSIS2 (GOLD‐MSIS) simulation—from a set of MSIS2 runs obtained by varying geomagnetic ap index values. From the MSIS‐GOLD run we found that the thermospheric density enhancement varies with altitude from 15% (at 150) to 80% (at 500 km). Independent simulations from the MAGE model also show a comparable enhancement in neutral density. These results suggest that even a modest storm could impact the thermospheric densities significantly and GOLD data can be used to improve the empirical and assimilative models of the thermosphere. Plain Language Summary: High speed plasma from the sun can bring energy, momentum, and particles into the Earth's upper atmosphere triggering a geomagnetic storm, which disturbs the thermosphere‐ionosphere (TI) system. It is observed that even minor geomagnetic events can have a significant impact on the TI system. In this work we have investigated the neutral properties of the thermosphere during a minor geomagnetic event using NASA‐Global‐scale Observations of the Limb and Disk (GOLD) mission observations. By calibrating the Mass Spectrometer Incoherent Scatter radar version 2 empirical model based on the temperature change observed by GOLD, we have found that the thermospheric density increased by 15% (at 150) to 80% (at 500 km). These results demonstrates that the GOLD data can help in improving thermospheric empirical models. Also, they can help satellite‐drag and space weather forecasters to find ways to improve their products. Key Points: Global‐scale Observations of the Limb and Disk (GOLD) observed a ∼60 K rise in lower‐to‐middle thermospheric temperature during a minor geomagnetic storm on 3–4 February 2022GOLD‐informed MSIS calculations indicate an increase in density by 15% (at 150) to 80% (500 km), which agrees with Multiscale Atmosphere‐Geospace Environment estimationGOLD Tdisk can be used in empirical and data assimilative forecasting models to improve thermospheric specifications [ABSTRACT FROM AUTHOR]

Objective: Systemic sclerosis (SSc) is an autoimmune disease characterized by progressive organ damage, which can be measured using the Scleroderma Clinical Trials Consortium Damage Index (SCTC‐DI). We aimed to identify whether distinct trajectories of damage accrual exist and to determine which variables are associated with different trajectory groups. Methods: Incident cases of SSc (<2 years) were identified in the Australian Scleroderma Interest Group and Canadian Scleroderma Research Group prospective registries. Group‐based trajectory modeling was used to identify SCTC‐DI trajectories over the cohort's first 5 annual visits. Baseline variables associated with trajectory membership in a univariate analysis were examined in multivariable models. Results: A total of 410 patients were included. Three trajectory groups were identified: low (54.6%), medium (36.2%), and high (10.3%) damage. Patients with faster damage accrual had higher baseline SCTC‐DI scores. Older age (odds ratio [OR] 1.57 [95% confidence interval (95% CI) 1.18–2.10]), male sex (OR 2.55 [95% CI 1.10–5.88]), diffuse disease (OR 6.7 [95% CI 2.57–17.48]), tendon friction rubs (OR 5.4 [95% CI 1.86–15.66]), and elevated C‐reactive protein level (OR 1.98 [95% CI 1.49–2.63]) increased the odds of being in the high‐damage group versus the reference (low damage), whereas White ethnicity (OR 0.31 [95% CI 0.12–0.75]) and anticentromere antibodies (OR 0.24 [95% CI 0.07–0.77]) decreased the odds. Conclusion: We identified 3 trajectories of damage accrual in a combined incident SSc cohort. Several characteristics increased the odds of belonging to worse trajectories. These findings may be helpful in recognizing patients in whom early aggressive treatment is necessary. [ABSTRACT FROM AUTHOR]

On 03 February 2022, SpaceX launched 49 Starlink satellites, 38 of which re‐entered the atmosphere on or about 07 February 2022 due to unexpectedly high atmospheric drag. We use empirical model (NRLMSIS, JB08, and HASDM) outputs as well as solar extreme ultraviolet occultation and high‐fidelity accelerometer data to show that thermospheric density was at least 20%–30% higher at 210 km relative to the 9 days prior to the launch due to consecutive geomagnetic storms related to solar eruptions from NOAA AR12936 on 29 January 2022. We model the orbital altitude and in‐track position of a Starlink‐like satellite in a low‐drag configuration at 200 km during minor (G1) and extreme (G5) geomagnetic storms to show that an extreme storm would have at least a factor of two higher impact, with cumulative in‐track errors on the order of 10,000 km after a 5‐day duration extreme storm. Comparison of the JB08 and NRL MSIS models relative to the HASDM model during modeled historical minor and extreme geomagnetic storms shows that in‐track errors on the order of 100 km per day at 250 km, decreasing to cumulative errors on the order of 1 km per day at 550 km during geomagnetic storms. We conclude that full‐physics, data assimilative, coupled models of the magnetosphere and upper atmosphere, as well as new operational satellite missions providing "nowcasting" data to launch controllers, space traffic coordinators, and satellite operators, are needed to prevent similar—or worse—orbital system impacts during future geomagnetic storms. Plain Language Summary: On 03 February 2022, SpaceX launched 49 Starlink satellites into staging orbits at 210 km above sea level prior to raising them to their operational altitudes of 550 km. The pre‐launch space weather briefing included no information about an ongoing geomagnetic storm. Excessive atmospheric drag due to the geomagnetic storm resulted in 38 of the satellites re‐entering the atmosphere on or about 07 February 2022. We use both models and direct measurements of the atmospheric density during the event to show that density values were enhanced by 20%–30% at the 210 km staging altitude relative to values prior to the geomagnetic storm onset, while they were enhanced 90%–160% at higher altitudes. We recommend improving our ability to model the upper atmospheric response to geomagnetic storms to provide accurate forecasts and actionable "nowcasts" of conditions in low Earth orbit to launch controllers, space traffic managers, and satellite operators. Key Points: Geomagnetic storms can cause large variations in neutral density and satellite drag, especially at Very Low Earth Orbit altitudesData assimilative empirical model results and observations during the Starlink event show 20%–30% neutral density enhancements at 210 kmFull‐physics data assimilative models and real‐time measurements of thermospheric conditions can mitigate impacts on low Earth orbit operations [ABSTRACT FROM AUTHOR]

This study quantifies mesosphere/lower thermosphere (MLT) oxygen chemical contributions to the global thermosphere-ionosphere (T-I) semiannual oscillation (SAO) using a series of numerical experiments from the National Center for Atmospheric Research (NCAR) thermosphereionosphere-mesosphere-electrodynamics general circulation model (TIME-GCM) that isolate essential chemical processes affecting O and O2 in the MLT region. We track the vertical dynamical, diffusive, and chemical fluxes of O and O2 in and out of two control volumes between ∼80 and 130 km using a finite volume approach to the individual species continuity equation to investigate their relative importance on the global T-I SAO. TIME-GCM results indicate that the global T-I SAO amplitude and phase is fairly insensitive to significant changes in odd oxygen chemical reaction rates in the MLT. While chemistry has an appreciable effect on O in the MLT region, sensitivity to changes in odd oxygen and odd hydrogen chemical rates appear to be offset by a consequent adjustment in the vertical bulk wind and eddy diffusive transport of O locally, rendering their effects inconsequential to the global T-I SAO aloft. The implications of our findings for reproducing a self-consistent global T-I SAO in the NCAR thermosphereionosphere-electrodynamics general circulation model (TIE-GCM) with a lower boundary near ∼100 km are discussed. Specifically, including latitude-season variations in O, O2, and N2 from NRLMSIS® 2.0 at the lower boundary of the TIE-GCM near ∼100 km improves its representation of the climatological T-I SAO. However, reformulating the TIE-GCM temperature lower boundary condition could further improve its ability to simulate the T-I SAO from first-principles. [ABSTRACT FROM AUTHOR]

Background: Malignant bowel obstruction is a common complication of ovarian cancer, resulting in limited oral intake. Home parenteral nutrition (HPN) may be offered to patients in this condition to meet nutritional requirements. However, it is not known how they experience being unable to eat. The present study reports how patients related to food when receiving HPN. Methods: The investigation was a qualitative study underpinned by phenomenology with women with advanced ovarian cancer in bowel obstruction receiving parenteral nutrition. Interview transcripts were analysed thematically guided by the techniques of Van Manen. Results: We recruited 20 women to the study. Participants were interviewed a maximum of four times and a total of 39 in‐depth longitudinal interviews were conducted. Participants could tolerate minimal amounts of food, if they had a venting gastrostomy. Not being able to eat engendered a sense of sadness and loss, and most women found it challenging to be in the presence of others eating. They adopted strategies to cope, which included fantasising about food and watching cookery programmes. These approaches were not a long‐term solution; either participants came to terms with their loss or the strategies became less effective in providing relief. Conclusions: Home parenteral nutrition meets the nutritional requirements of patients with malignant bowel obstruction but cannot replace the non‐nutritive functions of food. Healthcare professionals can offer a patient‐centred approach by acknowledging the difficulties that patients may face and, wherever possible, encourage them to focus on the positive benefits of interacting with people rather than the loss of eating on social occasions. [ABSTRACT FROM AUTHOR]

Accurate determination of thermospheric neutral density holds crucial importance for satellite drag calculations. The problem is twofold and involves the correct estimation of the quiet time climatology and storm time variations. In this work, neutral density estimations from two empirical and three physics‐based models of the ionosphere‐thermosphere are compared with the neutral densities along the Challenging Micro‐Satellite Payload satellite track for six geomagnetic storms. Storm time variations are extracted from neutral density by (1) subtracting the mean difference between model and observation (bias), (2) setting climatological variations to zero, and (3) multiplying model data with the quiet time ratio between the model and observation. Several metrics are employed to evaluate the model performances. We find that the removal of bias or climatology reveals actual performance of the model in simulating the storm time variations. When bias is removed, depending on event and model, storm time errors in neutral density can decrease by an amount of 113% or can increase by an amount of 12% with respect to error in models with quiet time bias. It is shown that using only average and maximum values of neutral density to determine the model performances can be misleading since a model can estimate the averages fairly well but may not capture the maximum value or vice versa. Since each of the metrics used for determining model performances provides different aspects of the error, among these, we suggest employing mean absolute error, prediction efficiency, and normalized root mean square error together as a standard set of metrics for the neutral density. Plain Language Summary: Thermospheric neutral density is the largest source of uncertainty in atmospheric drag calculations. Consequently, mission and maneuver planning, satellite lifetime predictions, collision avoidance, and orbit determination depend on the accurate estimation of the thermospheric neutral density. Thermospheric neutral density varies in different timescales. In short timescales, the largest variations occur due to the geomagnetic storms. Several empirical and physics‐based models of the ionosphere‐thermosphere system are used for estimating the variations in the neutral density. However, the storm time responses from the models are clouded by the climatology (background variations), upon which the effect of geomagnetic storms is superimposed. In this work, we show that it is critical to use reference levels for the neutral density to extract the true performance of the models for the evaluation of the storm time performances. We demonstrate that mean absolute error, prediction efficiency, and normalized root mean square error should be considered together for the performance evaluations, since each of them provides different aspects of the error. Key Points: Using the average and maximum values of neutral densities to determine the model performances can be misleadingRemoving the quiet time trend from the neutral density reveals the actual performance of the model in simulating the storm time variationsMean absolute error, prediction efficiency, and normalized root mean square error should be considered together for the evaluations [ABSTRACT FROM AUTHOR]

The specification and prediction of density changes in the thermosphere is a key challenge for space weather observations and modeling, because it is one result of complex interactions between the Sun and the terrestrial atmosphere and also because it is of operational importance for tracking objects orbiting in near‐Earth space. For low Earth orbit, neutral density variation is the most important uncertainty for propagation and prediction of orbital elements. A recent international conference conducted under the auspices of the National Aeronautics and Space Administration Community Coordinated Modeling Center included a workshop on neutral density modeling, using both empirical and numerical methods, and resulted in organization of an initial effort in model comparison and evaluation. Here we report on the exploitable density data sets available, the selected years and storm events, and the metrics for complete model assessment. Comparisons between five models (three empirical and two numerical) and neutral density data sets that include measurements by the CHAMP, GRACE, and GOCE satellites are presented as examples of the assessment procedure that will be implemented at Community Coordinated Modeling Center. The models in general performed reasonably well, although seasonal errors sometimes are present, and impulsive geomagnetic storm events remain challenging. Numerical models are still catching up to empirical methods on a statistical basis, but hold great potential for describing these short‐term variations. Key Points: We present density data, periods and events, and metrics for comprehensive and standardized thermosphere model assessmentA short description is given for the models evaluated in this studyExamples of the assessment are given for TIE‐GCM, CTIPe, NRLMSISE‐00, JB2008 and DTM2013 [ABSTRACT FROM AUTHOR]

Background: Previous studies have concluded that certain titanium oxide (TiO2) surface properties promote bone‐forming cell attachment. However, no comprehensive studies have investigated the effects of TiO2 surface and film morphology on hard and soft tissues. Purpose: The aim of this study is to understand the effects of TiO2 morphology on the proliferation and differentiation of murine preosteoblasts (MC3T3‐E1) and proliferation of human gingival fibroblasts (HGF‐1) using in vitro experiments. Materials and Methods: Samples were fabricated with several TiO2 thickness and crystalline structure to mimic various dental implant surfaces. in vitro analysis was performed for 1, 3, and 7 days on these samples to assess the viability of MC3T3‐E1 and HGF‐1 cells in contact with the modified oxide surfaces. Results: Results showed that HGF‐1 cells exhibited no significant difference in viability on modified oxide surfaces versus a titanium control across experiments. MC3T3‐E1 cells exhibited a significantly higher viability for the modified oxide surface in 1 day experiments, but not in 3 or 7 day experiments. Alkaline phosphatase expression in MC3T3‐E1 was not significantly different on modified oxide surfaces versus the control across all experiments. A slight positive trend in viability was observed for cells in contact with rougher modified oxide surfaces versus a titanium control in both cell types. Conclusions: These observations suggest that crystallinity and thickness do not affect the long‐term viability of hard or soft tissue cells when compared to a cpTi surface. Therefore, treatments like anodization on implant components may not directly affect the attachment of hard or soft tissue cells in vivo. [ABSTRACT FROM AUTHOR]

This paper presents measurements of the amplitudes and timings of the combined, annual, and semiannual variations of thermospheric neutral density, and a comparison of these density variations with measurements of the infrared emissions from carbon dioxide and nitric oxide in the thermosphere. The density values were obtained from measurements of the atmospheric drag experienced by the Challenging Minisatellite Payload, Gravity Recovery and Climate Experiment A, Gravity field and Ocean Circulation Explorer, and three Swarm satellites, while the optical emissions were measured with the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on the Thermosphere Ionosphere Mesosphere Energetics and Dynamics satellite. These data span a time period of 16 years. A database containing global average densities that were derived from the orbits of about 5,000 objects (Emmert, 2009, https://doi.org/10.1029/2009JA014102, 2015b, https://doi.org/10.1002/2015JA021047) was employed for calibrating these density data. A comparison with the NRLMSISE‐00 model was used to derive measurements of how much the density changes over time due to these seasonal variations. It is found that the seasonal density oscillations have significant variations in amplitude and timing. In order to test the practicality of using optical emissions as a monitoring tool, the SABER data were fit to the measured variations. Even the most simple fit that used only filtered carbon dioxide emissions had good correlations with the measured oscillations. However, the density oscillations were also well predicted by a simple Fourier series, contrary to original expectations. Nevertheless, measurements of the optical emissions from the thermosphere are expected to have a role in future understanding and prediction of the semiannual variations. Plain Language Summary: The uppermost atmosphere, known as the thermosphere, undergoes oscillations in the density of the neutral atoms and molecules, producing two peaks and valleys in the density in each year. The timing of of these "semiannual" variations or oscillations, as well as their amplitudes, tends to vary. Their unpredictability makes it harder to accurately model the amount of drag experienced by orbiting satellites. It had been noticed that the infrared light emitted by carbon dioxide molecules in the thermosphere has a tendency to follow the semiannual oscillations. Such emissions have been measured by an instrument on a NASA satellite for the past 16 years. We have compared these emissions with the variations in the semiannual oscillations that were derived from measurements of the drag seen by six different satellites flown by both NASA and the European Space Agency during the same time period, though not at the same time. The results of the comparison show how well the infrared emissions match the density oscillations, due to changes in both the composition and temperature of the thermosphere that influence both. Results show that further study will be needed to be able to accurately predict the density oscillations. Key Points: Four satellite missions are used to derive thermosphere density variations caused by annual and semiannual oscillations over a 16‐year periodVariations in thermospheric density are compared with emissions from carbon dioxide and nitric oxide measured with the SABER instrumentThe carbon dioxide emissions and simple Fourier series fits have good correlations with thermosphere density oscillations [ABSTRACT FROM AUTHOR]

Abstract: Background: Implant healing abutments (IHA) have a vital role in soft tissue healing after implant placement. Although there is thorough investigation on the implant surface, little is known about the effects potentially damaging oral conditions impose on healing abutments. Purpose: To characterize the surface of titanium healing abutments before and after clinical placement to understand the effects of the oral environment and time on the device surface. Materials and Methods: Ten regular Straumann IHA were subjected to characterization pre and postplacement to elucidate the effects of the oral environment on device surfaces. Changes in surface crystallinity, morphology, and elemental composition were monitored with Raman spectroscopy, scanning electron microscopy, optical microscopy, and x‐ray photoelectron spectroscopy, respectively. In addition, corrosion rate and polarization resistance were obtained to assess electrochemical device stability after placement. Results: Control analysis indicated the titanium oxide of IHAs was thicker than natural commercially pure titanium and had the structure of crystalline anatase. After removal, the abutments possessed large amounts of biological debris, visible scratches, and discoloration sparsely on the surface. Spectroscopic analysis revealed the titanium oxide on the surface of IHAs was structurally unchanged, with crystalline titanium dioxide still present on the surface. Electrochemical results revealed that implanted healing abutments possessed a significantly higher corrosion rate than controls (change in corrosion rate = 2.34 ± 0.58 nm/year). Conclusions: Healing abutments were stable in the oral environment due to the chemical stability of the oxide, and were likely subjected to abrasions from unintentional loading and oral hygiene techniques. [ABSTRACT FROM AUTHOR]

Abstract: Polar cap neutral density anomaly (PCNDA) with large mass density enhancements over the background has been frequently observed in the polar cap during magnetic storms. By tracing field lines to the magnetosphere from the polar ionosphere, we divide the polar cap into two regions, an open field line (OFL) region with field lines connecting to the magnetopause boundary and a distant tail field line (TFL) region threaded with magnetotail lobe field lines. A statistical study of neutral density observed by the Challenging Minisatellite Payload satellite during major magnetic storms with Dst < −100 from July 2001 to 2006 indicates that over 85% of density anomalies were detected in the TFL region, at about 18° to 25° equatorward the center of the OFL region. PCNDAs were frequently accompanied by plasma clouds with peak density greater than 105 #/cm3. Modeling of plasma cloud drift paths suggests that plasma clouds originating in the dayside ionosphere could convect through the OFL region following the zero‐potential line and reach the PCNDA locations. Plasma clouds could become stagnate in the TFL region, allowing a long duration of collisions with the neutral gas and possibly contributing to heating of PCNDAs. The PCNDA observations are interpreted as evidence that traveling atmospheric disturbance could be generated in the nightside polar cap. From the PCNDA size and speed of sound at 400 km, we derive an initial energy deposition duration for producing traveling atmospheric disturbance in the range from 0.5 to 2.5 hr. [ABSTRACT FROM AUTHOR]

We examine the response of the thermosphere to the impact of solar wind dynamic pressure enhancements using observations and global magneto-hydrodynamics (MHD) simulations by the OpenGGCM model. Combining neutral density observations from the Challenging Minisatellite Payload (CHAMP) and the Gravity Recovery and Climate Experiment (GRACE) satellites with simultaneous Poynting flux measurements from the Defense Meteorological Satellite Program (DMSP) F16, we find that thermospheric density as well as downward Poynting flux intensified shortly after a sudden enhancement of the solar wind dynamic pressure. The intensification manifested mostly on the dayside high-latitude region with peak intensity in the vicinity of the noon and prenoon cusp. OpenGGCM modeling results show that the ionospheric Joule heating increased abruptly in response to the sudden enhancement of the dynamic pressure in the same region as the observed Poynting flux and neutral density enhancements. The modeling results show that the enhanced Joule heating coincides, both in time and location, with the appearance of a pair of high-latitude localized field-aligned currents (FACs) in the cusp region. The FACs intensified and extended azimuthally. Coincidental with the solar wind dynamic pressure enhancement, the y component of the interplanetary magnetic field (IMF) B y became strongly positive and, in addition, had some large fluctuations. We explore the separate and combined effects of the dynamic pressure and IMF B y perturbations, with specifically designed simulation experiments that isolate the effect of each solar wind parameter. We find that the dynamic pressure enhancement is the primary source for the Joule heating and neutral density enhancements, but the IMF B y modulates the level of enhancement. [ABSTRACT FROM AUTHOR]

Recent studies have reported that thermospheric effects due to solar wind driving can be observed poleward of auroral latitudes. In these papers, the measured neutral mass density perturbations appear as narrow, localized maxima in the cusp and polar cap. They conclude that Joule heating below the spacecraft is the cause of the mass density increases, which are sometimes associated with local field-aligned current structures, but not always. In this paper we investigate neutral mass densities measured by accelerometers on the CHAllenging Minisatellite Payload (CHAMP) and Gravity Recovery and Climate Experiment (GRACE) spacecraft from launch until years 2010 (CHAMP) and 2012 (GRACE), approximately 10 years of observations from each satellite. We extract local maxima in neutral mass densities over the background using a smoothing window with size of one quarter of the orbit. The maxima have been analyzed for each year and also for the duration of each set of satellite observations. We show where they occur, under what solar wind conditions, and their relation to magnetic activity. The region with the highest frequency of occurrence coincides approximately with the cusp and mantle, with little direct evidence of an auroral zone source. Our conclusions agree with the 'hot polar cap' observations that have been reported and studied in the past. [ABSTRACT FROM AUTHOR]

Aim To investigate the impact of treatments used to detoxify dental implants on the oxide layer morphology and to infer how changes in morphology created by these treatments may impact re-osseointegration of an implant. Materials and methods Pure titanium (cpTi) and the alloy Ti6Al4V were subjected to a series of chemical treatments and mechanical abrasion simulating surface decontamination of dental implants. The morphology and roughness of the surface layer before and after treatment with these solutions were investigated with optical and atomic force microscopy (OM, AFM). The solutions employed are typically used for detoxification of dental implants. These included citric acid, 15% hydrogen peroxide, chlorhexidine gluconate, tetracycline, doxycycline, sodium fluoride, peroxyacetic acid, and treatment with carbon dioxide laser. The treatments consisted of both immersions of samples in solution and rubbing with cotton swabs soaked in solution for 1, 2, and 5 min. Cotton swabs used were analyzed with energy dispersive spectroscopy ( EDS). Results The microscopy investigation showed that corrosion and pitting of the samples were present in both metal grades with immersion and rubbing methods when employing more acidic solutions, which had pH <3. Mildly acidic solutions caused surface discoloration when coupled with rubbing but did not cause corrosion with immersion. Neutral or basic treatments resulted in no signs of corrosion with both methods. EDS results revealed the presence of titanium particles on all rubbing samples. Conclusion It was demonstrated in this study that acidic environments coupled with rubbing are able to introduce noticeable morphological changes and corrosion on the surface of both titanium grades. [ABSTRACT FROM AUTHOR]

Aim Nutrition is an important element of the Enhanced Recovery After Surgery ( ERAS) programme. Patients have previously indicated that nutrition is a key component of ERAS that requires improvement. Our aim was to explore the perioperative nutrition experiences of colorectal surgical patients to identify barriers and facilitators to the integration of nutrition within ERAS. Method Sixteen individuals undergoing colorectal surgery participated in a semi-structured interview between postoperative day three and hospital discharge. The topic guide was developed iteratively throughout the study; topics included preoperative counselling, carbohydrate loading, fasting and postoperative nutrition. A constant comparison technique was employed during coding, and an inductive thematic analysis was used. Validity was ensured by double coding a sample of transcripts. Results Findings are presented in the context of the following clinical themes: preoperative information, preoperative fasting, carbohydrate loading and nutritional drinks, postoperative diet and discharge. Individuals received too much general information which was repetitive, contradictory and not disease specific; this formed a key barrier affecting nutrition. Other barriers were negative experiences of nutritional drinks, stoma management, nausea and vomiting, and challenges from the hospital environment. Facilitators included interactions with staff, food accessibility and choice, and motivation for discharge. Conclusion The key barrier to adherence of perioperative nutrition protocols was poor provision of information. Targeted information regarding postoperative diet, stoma management and coping with nausea and vomiting would be beneficial for colorectal surgical patients. Easily accessible food provided by ward staff was considered a facilitator. [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate the reasons physicians provided when the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7) guidelines recommending a thiazide diuretic as a first line treatment for hypertension were not followed. A subsample of patients from a randomized controlled study who had uncontrolled blood pressure at an index visit and were not prescribed a thiazide were evaluated. Differences in groups that received any medication change or therapeutic lifestyle changes counseling and those that did not were compared. Differences in treatment were also compared for patients who received educational materials with or without telephone calls and financial incentive with a control group. The authors examined whether patients achieved blood pressure control in 12 months. The results show providers are not aggressive enough with getting blood pressure to goal and patients who are more educated about hypertension may be less likely to experience clinical inertia. [ABSTRACT FROM AUTHOR]

Focuses on the participation of African American college students, with emphasis on men, in leadership programs. Identification of some factors which affect black men; Information on minority group leadership; Reference to a study conducted on leadership perceptions among African American men.

Space weather is the main source of uncertainty in the position of all objects in low Earth orbit (LEO) below about 1,000 km. The main impact is strong variation in the neutral density of the thermosphere as it responds to radiative inputs from the Sun in the extreme ultraviolet wavelength range, energetic particle precipitation in the high‐latitude auroral zones, and global‐scale electrical currents generated during geomagnetic storms. Waves and instabilities from the lower atmosphere can also influence thermospheric density in complex ways. The variation in neutral density leads to variable drag forces on satellites flying through the thermosphere, which in turn causes orbital track changes. We currently lack the ability to accurately model and predict the neutral density changes in the thermosphere in response to space weather inputs. Operational empirical models of thermospheric density are inaccurate during space weather events, and mandate that LEO orbital tracks carry large "error ellipsoids" around all objects to account for positional uncertainty. This leads to many more "conjunction" warnings than necessary as large error ellipsoids are frequently calculated to intersect in orbit. As the LEO domain becomes more crowded with the advent of commercial "megaconstellations" we face a growing challenge to reduce orbital uncertainties by developing whole atmosphere models to enable timely and accurate forecasts of thermospheric conditions. We recommend that researchers, forecasters, and policy makers coordinate to ensure that space weather research and forecasting is tightly integrated into upcoming changes to the operational Space Traffic Management system. Key Points: Space weather is the main source of uncertainty in the position of objects in Low Earth Orbit (LEO) due to its impact on atmospheric dragLEO is increasingly crowded with active satellites and debris; many thousands of additional satellites are planned for the near futureResearchers and policy makers must advance our ability to predict and manage the growing satellite and debris environment in LEO [ABSTRACT FROM AUTHOR]

We investigate, for the first time with a spatial superposed epoch analysis study, the thermosphere global time response to 159 geomagnetic storms caused by coronal mass ejections (CMEs) observed in the solar wind at Earth's orbit during the period of September 2001 to September 2011. The thermosphere neutral mass density is obtained from the CHAMP (CHAllenge Mini-Satellite Payload) and GRACE (Gravity Recovery Climate Experiment) spacecraft. All density measurements are intercalibrated against densities computed by the Jacchia-Bowman 2008 empirical model under the regime of very low geomagnetic activity. We explore both the effects of the pre-CME shock impact on the thermosphere and of the storm main phase onset by taking their times of occurrence as zero epoch times (CME impact and interplanetary magnetic field B z southward turning) for each storm. We find that the shock impact produces quick and transient responses at the two high-latitude regions with minimal propagation toward lower latitudes. In both cases, thermosphere is heated in very high latitude regions within several minutes. The B z southward turning of the storm onset has a fast heating manifestation at the two high-latitude regions, and it takes approximately 3 h for that heating to propagate down to equatorial latitudes and to globalize in the thermosphere. This heating propagation is presumably accomplished, at least in part, with traveling atmospheric disturbances and complex meridional wind structures. Current models use longer lag times in computing thermosphere density dynamics during storms. Our results suggest that the thermosphere response time scales are shorter and should be accordingly adjusted in thermospheric empirical models. [ABSTRACT FROM AUTHOR]

Purpose: Interprofessional collaboration (IPC) among health professionals is well-recognised to enhance care delivery and patient outcomes. Emerging evidence suggests that the early socialisation of students in health professional programmes to teamwork may have a positive impact on their future as collaborative practitioners. With a purpose of contributing to growing evidence on the processes of professional identity construction, and to explore how early expectations and perceptions of IPC develop during professional socialisation and pre-licensure education, our study examined the early professional socialisation experiences among five groups of health professional students., Method: A qualitative, narrative approach was used to examine early professional socialisation among five programmes of health professional students (dentistry, medicine, nursing, pharmacy, physiotherapy) at an Atlantic Canadian University. In March and October 2016, students participated in interviews after first term (n = 44) and first year of study (n = 39). Interviews focused on participants' professional identify formation, as well as their perceptions and experiences of IPC. The authors analysed interview transcripts using narrative analysis., Results: Findings identify that despite the espoused importance of IPC within health professional training, students have a limited understanding of their professional roles and are largely focused on developing a uniprofessional, vs. interprofessional identity. Clinical experiences, role models and exposure to teamwork are critical to contextualise collaborative practice and enhance the development of an interprofessional identity., Conclusions: Findings can be used to guide the development of curricula that promote interprofessional identity development and IPC during early professional socialisation., (© 2020 Association for the Study of Medical Education and John Wiley & Sons Ltd.)

Finding ways to cope with social stigmatization is an important aspect of achieving adaptation for people living with visible genetic differences. This study describes the way individuals with craniofacial differences use an innovative photography and video experience with Positive Exposure (PE), a non-profit organization based in New York City, as a way to cope with their conditions. Thirty-five individuals between 12 and 61 years of age participated in this study. We administered surveys comprised of open-ended qualitative questions and quantitative measures designed to assess self-esteem, perceived stigma, and hopefulness. Data for this analysis was generated from the written questionnaires and interview transcripts. Most participants reported high levels of self-esteem and hopefulness, suggesting that they were relatively well adapted to their condition. Almost all participants described experiences of stigmatization throughout their lives. However, participants demonstrated their ability to implement a variety of coping strategies to manage stigma. "Helping others" emerged as a prominent strategy among participants, aiding in the often lifelong process of adapting to their genetic difference. PE was described as an avenue through which participants could reach out to individuals and society at large, helping them adapt further to their condition. "Helping others" may also benefit individuals with craniofacial differences who do not consider themselves to be well adapted to their condition. Health care providers can collaborate with PE, advocacy groups and other community or support groups to identify additional ways individuals with craniofacial differences can help themselves by reaching out to others., (2008 Wiley-Liss, Inc.)